Basic/Translational Science/Team Science
3367 A Mouse Model of APOE Genotype in Chemotherapy Related Cognitive Impairment
- Tamar Demby, G. William Rebeck, Christopher Albanese, Olga C. Rodriguez, Yichien Lee, Jeanne Mandelblatt
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- 26 March 2019, p. 1
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OBJECTIVES/SPECIFIC AIMS: Chemotherapy-related cognitive impairment (CRCI) affects 15-35% of breast cancer survivors and constitutes a significant challenge for survivor quality of life. Among older breast cancer survivors who received chemotherapy treatment, carriers of at least one ɛ4 allele of the APOE gene, which encodes apolipoprotein E, are at higher risk for developing CRCI than non-carriers. APOE4 is well characterized as the strongest genetic risk factor for Alzheimer’s disease, but how it contributes to CRCI is not yet understood, and no animal models of APOE genotype and CRCI have yet been established. To better understand how APOE4 acts as a risk factor for CRCI, we used APOE targeted replacement (TR) mice to develop a model of its effects on cognition following treatment with doxorubicin, a chemotherapy drug commonly used in breast cancer treatment. METHODS/STUDY POPULATION: Twelve-to-thirteen month old APOE3 and APOE4 targeted replacement mice expressing human APOE3 or human APOE4 under control of the endogenous murine promoter were treated with 10 mg/kg doxorubicin or equivolume saline given via two IP injections spaced one week apart. One week post-treatment, mice were tested using Open Field and Elevated Zero apparatuses to assess baseline locomotive activity and anxiety and exploratory behaviors. Five weeks post-treatment, mice were assessed using the Barnes Maze over four days of training trials and one 72 hour memory probe. RESULTS/ANTICIPATED RESULTS: We found no differences in Open Field and Elevated Zero behavior, indicating limited influence of doxorubicin treatment on locomotive and anxiety behaviors in both genotypes. During Barnes Maze training, APOE4 mice treated with doxorubicin showed increased latency compared to untreated APOE4 mice as well as treated and untreated APOE3 mice, indicating deficiencies in spatial learning. In APOE3 mice, no differences in performance were seen between doxorubicin-treated and untreated mice (n = 15-16/group, p <.0001). DISCUSSION/SIGNIFICANCE OF IMPACT: These results indicate that APOE4 targeted replacement mice have specific cognitive vulnerabilities to doxorubicin treatment that can be reliably detected using the Barnes Maze assessment. Future directions include experiments to determine how other chemotherapy drugs or drug combinations impact cognition of APOE4 mice. Ultimately this model may be used to assess preventive measures or therapies for CRCI in the vulnerable APOE4 carrier population with the ability to validate cognitive impacts of these interventions.
3552 Advancing Glioblastoma (GBM) drug regimen development to support combination therapy through integrated PKPD modeling and simulation-based predictions
- Saugat Adhikari, Harlan E. Shannon, Karen E. Pollok, Robert E. Stratford
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- 26 March 2019, pp. 1-2
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OBJECTIVES/SPECIFIC AIMS: Despite advancements in therapies, such as surgery, irradiation (IR) and chemotherapy, outcome for patients suffering from glioblastoma remains fatal; the median survival rate is only about 15 months. Even with novel therapeutic targets, networks and signaling pathways being discovered, monotherapy with such agents targeting such pathways has been disappointing in clinical trials. Poor prognosis for GBM can be attributed to several factors, including failure of drugs to cross the blood-brain-barrier (BBB), tumor heterogeneity, metastasis and angiogenesis. Development of tumor resistance, particularly to temozolomide (TMZ), creates a substantial clinical challenge.The primary focus of our work is to rationally develop novel combination therapies and dose regimens that mitigate resistance development. Specifically, our aim is to combine TMZ with small molecule inhibitors that are either currently in clinical trials or are approved drugs for other cancer types, and which target the disease at various resistance signaling pathways that are induced in response to TMZ monotherapy. METHODS/STUDY POPULATION: To accomplish this objective, an integrated PKPD modeling approach is used. The approach is largely based on the work of Cardilin, et al, 2018. A PK model for each drug is first defined. This is subsequently linked to a PD model description of tumor growth dynamics in the presence of a single drug or combinations of drugs. A key outcome of these combined PKPD models are tumor static concentration (TSC) curves of dual or triple combination drug regimens that identify combination drug exposures predicted to arrest tumor growth. This approach has been applied to TMZ in combination with abemaciclib (a dual CDK4/6 small molecule inhibitor) based on data from a published study evaluating abemaciclib efficacy in combination with TMZ in a glioblastoma xenograft model (Raub, et al, 2015). RESULTS/ANTICIPATED RESULTS: A PKPD model was developed to predict tumor growth kinetics for TMZ and abemaciclib monotherapy, as well as combination therapy. Population PK models in immune deficient NSG mice for temozolomide and abemaciclib were developed based on data obtained from original and published studies. Subsequently, the PK model was linked to tumor volume data obtained from U87-MG GBM subcutaneous xenografts, again using both original data as well as data from the Raub, et al, 2015 study. Model parameters quantifying tumor volume dynamics were precisely estimated (coefficient of variation < 30%). The developed PKPD model was used to calculate plasma concentrations of TMZ and abemaciclib that would arrest tumor growth, as well as combinations of concentrations of the two drugs that would accomplish the same endpoint. This so-called TSC curve for the TMZ and abemaciclib combination pair evidenced an additive effect of the two agents when administered together. These results will be presented. In addition, results from on-going PKPD studies of TMZ in combination with two other small molecule inhibitors, RG7388, an MDM2 inhibitor, and GDC0068, an AKT inhibitor, will also be presented. DISCUSSION/SIGNIFICANCE OF IMPACT: Our long-term goals are to further elucidate SOC-induced responses in GBM and establish combination treatment regimens that are safe and significantly improve therapeutic efficacy. Collectively, our studies will broadly influence chemotherapy of GBM by establishing a process to rationally design combination approaches that mitigate resistance development. These studies will ultimately provide opportunities to study other targeted agents tailored to individual molecular signatures of GBM, as well as other tumor types.
3145 An Evaluation of Machine Learning and Traditional Statistical Methods for Discovery in Large-Scale Translational Data
- Megan C Hollister, Jeffrey D. Blume
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- 26 March 2019, p. 2
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OBJECTIVES/SPECIFIC AIMS: To examine and compare the claims in Bzdok, Altman, and Brzywinski under a broader set of conditions by using unbiased methods of comparison. To explore how to accurately use various machine learning and traditional statistical methods in large-scale translational research by estimating their accuracy statistics. Then we will identify the methods with the best performance characteristics. METHODS/STUDY POPULATION: We conducted a simulation study with a microarray of gene expression data. We maintained the original structure proposed by Bzdok, Altman, and Brzywinski. The structure for gene expression data includes a total of 40 genes from 20 people, in which 10 people are phenotype positive and 10 are phenotype negative. In order to find a statistical difference 25% of the genes were set to be dysregulated across phenotype. This dysregulation forced the positive and negative phenotypes to have different mean population expressions. Additional variance was included to simulate genetic variation across the population. We also allowed for within person correlation across genes, which was not done in the original simulations. The following methods were used to determine the number of dysregulated genes in simulated data set: unadjusted p-values, Benjamini-Hochberg adjusted p-values, Bonferroni adjusted p-values, random forest importance levels, neural net prediction weights, and second-generation p-values. RESULTS/ANTICIPATED RESULTS: Results vary depending on whether a pre-specified significance level is used or the top 10 ranked values are taken. When all methods are given the same prior information of 10 dysregulated genes, the Benjamini-Hochberg adjusted p-values and the second-generation p-values generally outperform all other methods. We were not able to reproduce or validate the finding that random forest importance levels via a machine learning algorithm outperform classical methods. Almost uniformly, the machine learning methods did not yield improved accuracy statistics and they depend heavily on the a priori chosen number of dysregulated genes. DISCUSSION/SIGNIFICANCE OF IMPACT: In this context, machine learning methods do not outperform standard methods. Because of this and their additional complexity, machine learning approaches would not be preferable. Of all the approaches the second-generation p-value appears to offer significant benefit for the cost of a priori defining a region of trivially null effect sizes. The choice of an analysis method for large-scale translational data is critical to the success of any statistical investigation, and our simulations clearly highlight the various tradeoffs among the available methods.
3395 An Injectable Sulfonated Reversible Thermal Gel for Controlled and Localized Delivery of Vascular Endothelial Growth Factor to Promote Cardiac Protection After a Myocardial Infarction
- Adam J Rocker, David Lee, Maria Cavasin, Daewon Park
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- 26 March 2019, pp. 2-3
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OBJECTIVES/SPECIFIC AIMS: This study aims to evaluate an injectable sulfonated reserve thermal gel (SPSHU-PNIPAM) for angiogenic growth factor delivery by examining the vascularization and cardioprotective properties of the polymer system. This study could lead to clinical translation by moving into larger animal studies and eventually clinical trials. The success of this study was determined by analyzing the results of echocardiography data on cardiac function (ejection fraction, fractional shortening, and left ventricle inner diameter) and assessment of histological staining on cardiac tissue (fibrotic tissue formation, infarct size, wall thinning, blood vessel cell counts, and vessel size quantification) after MI. Five groups were compared for this study: saline, VEGF, SPSHU-PNIPAM, SPSHU-PNIPAM loaded with VEGF, and no injection (sham). Significant statistical differences between control groups and polymer injection groups, when p < 0.05, indicates successful outcomes from this study. METHODS/STUDY POPULATION: SPSHU-PNIPAM Polymer Synthesis: SPSHU-PNIPAM was synthesized as previously described. Briefly, PSHU was synthesized with N-BOC serinol, urea, and HDI at 90 °C for 7 days. PSHU was deprotected in DCM and TFA at room temperature for 45 min. PNIPAM was conjugated to the deprotected PSHU using EDC and NHS at room temperature for 24 h. PSHU-PNIPAM was sulfonated with 1,3-propanesultone and potassium tert-butoxide at 60 °C for 3 days. Surgical Procedure: Male C57BL/6 mice weighing 24-28 g were anaesthetized using isoflurane and artificial ventilation provided. A small left thoracotomy incision was made at the left fourth intercostal space to expose the heart, and the proximal left anterior descending coronary artery was ligated for 45 min. The coronary artery was then released and 30 μl injections of saline, SPSHU-PNIPAM (1% w/v), bolus VEGF (200 ng), or SPSHU-PNIPAM + VEGF (1%, 200 ng) were injected intramyocardially at the infarcted site and the incision closed. Echocardiography and Histological Staining: Standard serial transthoracic echocardiography was performed while simultaneously recording ECG to assess cardiac morphology and left ventricular function. Immunohistochemistry and histology staining procedures were used to identify: fibrotic tissue formation, infarct size, wall thinning, blood vessel cell counts, and vessel size quantification. These were performed according to manufacturer instructions or by previously published criteria. Statistical Analysis: Two-tailed t-test assuming unequal variances was used to determine significant differences between two groups. Analysis of variance (ANOVA) was used to determine significant differences between three or more groups followed by Tukey-Kramer to determine significant differences between two groups as appropriate. Statistical significance was considered when p < 0.05. References: Lee, D. J., Rocker, A. J., Bardill, J. R., Shandas, R. and Park, D. (2018), A sulfonated reversible thermal gel for the spatiotemporal control of VEGF delivery to promote therapeutic angiogenesis. J Biomed Mater Res. doi:10.1002/jbm.a.36496. RESULTS/ANTICIPATED RESULTS: Echocardiography results: Ejection fraction improved for the SPSHU-PNIPAM groups compared to the saline, VEGF, and no injection controls (Figure 1). SPSHU-PNIPAM either loaded with or without VEGF seemed to have very similar treatment effects for ejection fraction and fractional shortening. This indicates that the more significant component of the cardioprotective effects of the hydrogel system is the biomaterial itself rather than the release of VEGF (Figure 1). However, the only statistically significant improvement for ejection fraction, fractional shortening, and left ventricular inner diameter that was observed compared to the saline, VEGF, and no injection controls was the SPSHU-PNIPAM + VEGF group (Figure 1). Histology Results: After analyzing Masson trichrome staining, SPSHU-PNIPAM + VEGF demonstrated the smallest infarct size after MI reperfusion injury and was statistically reduced compared to the saline, VEGF, and no injection controls (Figure 2). Furthermore, left ventricular wall thickness showed that the SPSHU-PNIPAM + VEGF treatment group reduced the wall thinning resulting from MI. The SPSHU-PNIPAM group without VEGF displayed a thicker ventricular wall as well, which may be attributed to the increased mechanical stability with the intramyocardial injection of the biomaterial (Figure 2). The immunohistochemical results for vascularization show that the SPSHU-PNIPAM + VEGF group significantly increased the number of functional vascular endothelial cells compared to the saline, VEGF, SPSHU-PNIPAM, and no injection controls (Figure 3). Additionally, the SPSHU-PNIPAM + VEGF group showed a significant increase in total vessel formation compared to the control groups, although there was no significant difference compared to SPSHU-PNIPAM without VEGF (Figure 3). The promotion of angiogenesis, without the delivery of VEGF, may be attributed to inflammation induced vascularization, including VEGF dependent vascularization that is initiated via signal transducer and activator of transcription 3 (STAT3) pathway that is induced by the pro-inflammatory cytokine interleukin 6. DISCUSSION/SIGNIFICANCE OF IMPACT: The SPSHU-PNIPAM loaded with VEGF was evaluated for therapeutic angiogenesis to protect cardiac function after MI. Treatment with SPSHU-PNIPAM showed improved cardiac function and vascularization; however, the additional delivery of VEGF showed inadequate additional therapeutic benefits. Further investigation will include optimizing VEGF release characteristics including both loading amount and release rate. The decline of ejection fraction and fractional shortening after MI were reduced, while left ventricular internal diameter showed reduced ventricular dilation. Both infarct size and left ventricular wall thinning decreased while an increase in the vessel formation was observed. These results demonstrate the SPSHU-PNIPAM biomaterial has cardioprotective and increased vascularization properties for the treatment of MI.
3265 Analysis of High-Dimensional Patient Data in Characterizing Alzheimer’s Disease Progression
- Daniel Baer, Andrew B. Lawson, Brandon Vaughan, Jane E. Joseph
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- 26 March 2019, p. 3
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OBJECTIVES/SPECIFIC AIMS: Our research hypothesis is that resting state fMRI (rsfMRI) data can be used to identify regions of the brain which are associated with cognitive decline in patients – thereby providing a tool by which to characterize AD progression in patients. METHODS/STUDY POPULATION: We used data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to analyze Mini-Mental State Examination (MMSE) questionnaire scores from 14 patients diagnosed with AD at two measurement occasions. RsfMRI data was available at the first of these occasions for these patients. These rsfMRI data were summarized into 264 node-based graph theory measures of clustering coefficient and eigenvector centrality. To address our research hypothesis, we modeled changes in patient MMSE scores over time as a function of these rsfMRI data, controlling for relevant confounding factors. This model accounted for the high-dimensionality of our predictor data, the longitudinal nature of the outcome, and our desire to identify a subset of regions in the brain most associated with the MMSE outcome. RESULTS/ANTICIPATED RESULTS: The use of either the clustering coefficient or eigenvector centrality rsfMRI predictors in modeling MMSE scores for patients over time resulted in the identification of different subsets of brain regions associated with cognitive decline. This suggests that these predictors capture different information on patient propensity for cognitive decline. Further work is warranted to validate these results on a larger sample of ADNI patients. DISCUSSION/SIGNIFICANCE OF IMPACT: We conclude that different rsfMRI graph theory measures capture different aspects of cognitive function and decline in patients, which could be a future consideration in clinical practice.
3449 Bacterial biotransformation of chemotherapeutics may promote diversity among the intestinal microbiota
- Ryan Andrew Blaustein, Patrick Casey Seed, Erica Marie Hartmann
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- 26 March 2019, p. 3
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OBJECTIVES/SPECIFIC AIMS: This study aims to test the hypothesis that bacterial biotransformation of chemotherapeutics promotes gut microbial diversity by enhancing persistence of drug-sensitive taxa. METHODS/STUDY POPULATION: The impacts of doxorubicin on a model community of gut bacteria was investigated in vitro in anaerobic batch culture. The synthetic community was composed of specific members predicted by genomic analysis to be sensitive to the therapeutic (i.e., Clostridium innocuum, Lactobacillus sp.), resistant via putative biotransformation (i.e., Escherichia coli, Klebsiella pneumoniae), or resistant via putative efflux (i.e., Enterococcus faecalis). Bacterial growth was monitored in monocultures by measuring OD600 and standard plate counts, and in mixed cultures by strain-targeted qPCR. Doxorubicin concentration was detected via absorbance assay. RESULTS/ANTICIPATED RESULTS: Strains with predicted resistance to doxorubicin by drug biotransformation significantly lowered concentrations of the drug in culture media. In contrast, E. faecalis proved resistant without evidence of drug transformation. Predicted sensitive strains were growth-repressed by the doxorubicin, but able to grow in spent media where biotransformation had occurred. However, they remained growth-repressed in spent media from E. faecalis where drug transformation had not been observed. Bacterial growth kinetics in mixed batch culture were dependent on starting bacterial concentrations and timing of drug exposure. DISCUSSION/SIGNIFICANCE OF IMPACT: This work will be extended to model microbial community responses to doxorubicin as a factor of microbial interactions and extent of drug transformation prior its exposure to sensitive strains. The resulting model will have translational implications for mitigating health risks during pediatric cancer treatment.
3071 Cell Survival in Corneal Endothelial Dystrophies
- Rajalekshmy Shyam, Diego Ogando, Moonjung Choi, Joseph Bonanno
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- 26 March 2019, p. 4
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OBJECTIVES/SPECIFIC AIMS: Purpose - The goal of this study is to understand how loss of the membrane protein SLC4A11 alters endothelial cell metabolism thereby producing Corneal Endothelial Dystrophy. Studies from our lab indicated that glutamine-dependent mitochondrial dysfunction is one of the outcomes of SLC4a11 loss. In the current study, we ask if autophagy and mitophagy pathways and the signaling pathways that regulate these processes are altered in SLC4a11 KO cells. METHODS/STUDY POPULATION: Methods – Immortalized mouse WT and SLC4a11 KO cell lines were incubated in DMEM with and without 0.5mM glutamine for 6 hours. In order to assess mitophagy, cells were stained using Lysotracker Red and Mitotracker Green. Colocalization co-efficients of red and green channels were obtained for at least 35 cells using Zeiss-Zen Pro software. Student’s t-test was used to determine statistical significance. For Western Blots, antibodies against LC3b, AMPK, pAMPK, and b-actin were used to examine autophagy flux and potential signaling pathways that regulate autophagy. RESULTS/ANTICIPATED RESULTS: Results – In the presence of glutamine, the colocalization co-efficient of Lysotracker Red and Mitotracker Green channels was significantly increased in KO cells (0.74 ±0.18) relative to WT (0.58±0.20) with a p-value ≤0.0024. In the absence of glutamine, the colocalization co-efficient was reversed, for KO cells 0.54 ±0.14 and for WT cells 0.77±0.0.16 with a p-value ≤0.0001, suggesting increased mitophagy by glutamine in KO cells. Western Blots indicated that glutamine increased autophagy flux, as indicated by increased levels of LC3b following bafilomycin A treatment in KO cells. Concomitantly, there was an increase in pAMPK/AMPK levels suggesting a potential mechanism for increased mitophagy. DISCUSSION/SIGNIFICANCE OF IMPACT: Conclusion and Future studies –Our data indicates enhanced mitophagy as well as autophagy in SLC4a11 KO cells. Future studies will determine whether these processes regulate cell survival in mouse models of corneal endothelial dystrophies.
3069 Characterizing the Neural Signature of Metabolic Syndrome
- Eithan Kotkowski, Larry R. Price, Crystal G. Franklin, Maximino Salazar, Ralph A. DeFronzo, David Glahn, John Blangero, Peter T. Fox
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- 26 March 2019, p. 4
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OBJECTIVES/SPECIFIC AIMS: Our objective is to understand the influence of the features comprising metabolic syndrome (central obesity, raised fasting plasma glucose, triglycerides, blood pressure, and decreased HDL cholesterol) on brain structure in men and women. With the understanding that MetS is a strong predictor of gray matter volume loss in specific brain regions, in this study we sought to quantify the influence of each of the metabolic syndrome biometric variables on the structures involved in the neural signature of metabolic syndrome. METHODS/STUDY POPULATION: We conducted multiple linear regression analyses on a cross-sectional sample of 800 individuals from the Genetics of Brian Structure (GOBS) image archive (352 men and 448 women). GOBS is an offshoot of the San Antonio Heart Study involving an extended pedigree of Mexican Americans from the greater San Antonio area. Its goal is to localize, identify, and characterize genes/quantitative trait loci associated with variations in brain structure and function (Winkler, 2010). The archive has continuously added participants from approximately 40 families since 2006. Neuroanatomic (T1-weighted MRI scans obtained on a Siemens 3T scanner and processed using FSL), neurocognitive, and biometric phenotypes have been obtained for each subject (including blood lipids). Linear regressions were run using SPSS and incorporated biometric and gray matter volume values obtained from 800 GOBS participants. RESULTS/ANTICIPATED RESULTS: Linear regressions incorporating metabolic syndrome variables as dependent variables and gray matter volume from regions involved in the neural signature of metabolic syndrome as predictors show significant predictive patterns that are largely similar between men and women, with some differences. Another linear regression conducted with gray matter volume from the neural signature of metabolic syndrome as the dependent variable and metabolic syndrome variables as predictors show that waist circumference and triglycerides are the greatest predictors of gray matter volume loss in men, and fasting plasma glucose and waist circumference are the greatest predictors of gray matter volume loss in women. DISCUSSION/SIGNIFICANCE OF IMPACT: Significant sex differences in the relationships between metabolic syndrome variables and gray matter volume changes between brain regions comprising the neural signature of metabolic syndrome were identified. waist circumference, fasting plasma glucose, and triglycerides are the most reliable predictors of gray matter volume loss. The variance in gray matter volume of the neural signature of metabolic syndrome in men is more significantly explained by waist circumference and triglycerides (when accounting for age) and in women is more significantly explained by waist circumference and fasting plasma glucose (when accounting for age). A model of metabolic syndrome that emphasizes a risk of neurodegeneration should focus on waist circumference for both men and women and weigh the remaining variables accordingly by sex (triglycerides in men and fasting plasma glucose in women).
3375 Chronic inflammation promotes intestinal macrophages to become modulators of the Notch pathway
- Eliseo Castillo
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- 26 March 2019, pp. 4-5
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OBJECTIVES/SPECIFIC AIMS: The purpose of this research was to investigate how chronic inflammation promotes the generation of proinflammatory intestinal macrophages and if macrophages contribute to intestinal inflammation through Notch activation. METHODS/STUDY POPULATION: We utilized two animal models of chronic colitis, the chronic DSS-induced colitis mouse model and the spontaneous enterocolitis development in IL-10-deficient mice to investigate the role of chronic inflammation in the generation of proinflammatory intestinal macrophages and its influence in notch signaling. Bone marrow-derived monocytes were collected from each group and differentiated into macrophages (BMM) for gene and protein analysis. Ex vivo phenotypical and functional analysis of colonic macrophages was assessed as was the presence of goblet cells and mucosal T cells. In addition, we analyzed the development of goblet cell differentiation in colonoids in a co-culture system with proinflammatory macrophages. RESULTS/ANTICIPATED RESULTS: Our chronic inflammation models revealed an increase in proinflammatory macrophages present in the lamina propria and that these cells expressed significantly higher levels of notch ligand, Jagged1. Jagged 1 has been shown to enhance TH1 differentiation and T cells isolated from the mucosa of both chronic colitis models display strong TH1 skewing compared to controls. Chronic inflammation also contributes to intestinal barrier defects, enhanced permeability and bacterial translocation. We believe this enhanced intestinal permeability and subsequent bacterial translocation promote Jagged1 expression in intestinal macrophages. To support this concept, we show TLR stimulation induces the upregulation of Jagged1 in BMM. Additionally, the generation of BMM from our chronic DSS-induced colitis mice or age matched controls, revealed BMM derived from a host of chronic inflammation were skewed to a proinflammatory state prior to stimulation showing increased gene expression of several proinflammatory molecules including IL-1α, IL-1β, IL-12 and TNF-α. This would suggest monocytes migrating to the intestinal mucosa have more potential to become proinflammatory instead of traditional anti-inflammatory macrophages. Furthermore, proinflammatory notch ligand-positive macrophages co-cultured with colonoids, derived from unperturbed mice, significantly decreased the number of mucus producing goblet cells. In support of this observation, notch activation in intestinal stem cells promote absorptive (i.e. colonocytes) cell differentiation and prevents secretory cell (i.e. goblet cells) differentiation. DISCUSSION/SIGNIFICANCE OF IMPACT: Taken together, our results strongly suggest chronic inflammation modulates macrophages role in maintaining intestinal homeostasis through possible notch activation in both T cells and the intestinal epithelial barrier.
3508 Ciclopirox Olamine Demonstrates Inhibitory Effects on Esophageal Tumor Cells
- Randi Ryan, Shrikant Anant, Prabhu Ramamoorthy, Dharmalingam Subramaniam, Scott Weir
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- 26 March 2019, p. 5
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OBJECTIVES/SPECIFIC AIMS: Drug repositioning has the potential to accelerate translation of novel cancer chemotherapeutics from bench to bedside. The goal of this study was to determine the effects of ciclopirox olamine (CPX) on esophageal tumor cells. METHODS/STUDY POPULATION: We tested the effect of CPX on four esophageal cancer cell lines, assessing cell proliferation and viability by hexosaminidase and clonogenicity assay, respectively. We analyzed the effects of CPX on three-dimensional (3D) esophageal tumor cell spheroids. We also analyzed effects on cell cycle by flow cytometry. For mechanism, we performed western blots for proteins involved in cell cycle regulation, apoptosis and the Wnt/β-catenin pathway. For in vivo effects, we performed a murine xenograft model with intraperitoneal administration of CPX (100 mg/Kg body weight daily). RESULTS/ANTICIPATED RESULTS: CPX inhibited growth of all cell lines in a time and concentration-dependent manner. CPX also inhibited growth of esophageal spheroids. Cell cycle analysis demonstrated G0/G1 arrest in cells treated with CPX. Western blot analyses demonstrated decreased expression of cyclinD1, CDK4, CDK6, and transcriptionally active β-catenin, supporting the role of CPX in cell cycle inhibition and decreased β-catenin activity. Finally, treatment of nude mice with CPX significantly decreased tumor xenograft volume. DISCUSSION/SIGNIFICANCE OF IMPACT: CPX demonstrates anti-tumor properties in esophageal cancer cell lines. The current results justify further research into the mechanism of this inhibition. Additionally, given its established safety in humans, CPX is a potential candidate for repositioning as an adjunct treatment for esophageal cancer.
3389 Coagulation Factor Xll-mediated contact system and its role in adaptive and innate immune cell movement
- Emily Beltran, Tukisa Smith, Beth Graczyk, Jan Breslow, Manish Ponda
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- 26 March 2019, pp. 5-6
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OBJECTIVES/SPECIFIC AIMS: The objectives of this study are to 1) expand upon the paradigm of HK-D5 accelerated immune cell chemotaxis; 2) characterize the role of FXII in murine models of immune-mediated disease using FXII KO mice and a small molecule inhibitor of FXIIa. METHODS/STUDY POPULATION: To test whether the addition of HK-D5 peptide would accelerate C-C chemokine receptor type 2 (CCR2)-mediated chemotaxis in vitro, a real-time transwell chemotaxis assay was developed utilizing human THP-1 monocyte cell line (Fig 1). For in vivo studies, both pharmacologic FXIIa antagonism and FXll KO mice were used. Genotyping, histopathological review, FXll protein expression, and active partial thromboplastin time (aPTT) measurements were used to phenotypically characterize FXII KO mice compared to C57BL/6 wild type mice (Fig 2). Subsequently, the FXll KO mice were studied in varied models of immune-mediated disease, including LPS-induced sepsis and experimental autoimmune encephalitis (EAE), to see if and how the absence of FXll can mitigate disease severity. The EAE model involved active immunization with myelin oligodendrocyte glycoprotein (MOG) and measurement of established clinical disease severity scores. The LPS sepsis model involved an intraperitoneal injection of LPS followed by 48-hour monitoring of core body temperature using subdermal temperature transponders as a proxy for inflammatory events related to septic shock (Fig 3). RESULTS/ANTICIPATED RESULTS: HK-D5 significantly accelerates CCR2-mediated chemotaxis compared to chemokine alone (p = 0.001) similar to HK-D5’s ability to accelerate CCR7-mediated chemotaxis as previously established. The FXll KO mice were backcrossed to the C57BL/6J background and confirmed by genotyping and complete absence of FXII protein in plasma. Compared to the control, FXII KO mice have a significantly prolonged aPTT without evidence of bleeding abnormalities, which confirms the expected phenotype previously described and recapitulates what is observed in Factor XII deficiency in humans. KO mice showed no significant gross or histopathological differences in secondary lymphoid structures compared to the control. Immunohistochemistry confirmed well-organized lymphoid structures with intact B- and T-cell populations. FXll KO mice are protected in LPS-induced septic shock and EAE models. Regarding the EAE model, FXIIa inhibition significantly reduced disease severity compared to control. In the LPS model, FXll KO mice recover within 24 hours after LPS-challenge measured subjectively and objectively by core body temperature measurement. DISCUSSION/SIGNIFICANCE OF IMPACT: The current study and previous findings suggest a novel immune signaling mechanism by which a peptide fragment of high molecular-weight kininogen (HK-D5) acts as an accelerant of both innate and adaptive immune cell chemotaxis in multiple immune contexts. This has broad implications regarding a mechanism of immune-mediated inflammation in a variety of disease states, which might be amenable to the targeting this pathway for therapeutic intent.
3013 Combined Annulus Fibrosus and Nucleus Pulposus Repair Prevents Degeneration in the Ovine Lumbar Spine
- Stephen Sloan, Christoph Wipplinger, Sirtac Kirnaz, Rodrigo Navarro-Ramirez, Antonella Schivinato, Roger Härtl, Lawrence Bonassar
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- 26 March 2019, p. 6
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OBJECTIVES/SPECIFIC AIMS: The objective of this study is to assess the efficacy of combined AF and NP repairs to prevent degenerative changes and restore native disc morphology in an in vivo large animal model. We hypothesize that combined repairs will prevent disc degeneration following injury to a greater extent than the individual repairs after 6 weeks in vivo, as demonstrated through disc height measurements and disc morphology. METHODS/STUDY POPULATION: A total of 8 skeletally mature female Finn sheep were used in this study. Following a previously described method, IVDs from L1 to L6 of the lumbar spine were exposed using a lateral access, extraperitoneal approach5. IVDs were randomized into 5 treatment groups: 1) intact discs, 2) discs injured via a 3 cm x 1 cm box annulotomy and partial nucleotomy, 3) injury followed by a high density collagen (HDC) AF patch, 4) injury followed by injection of a modified hyaluronic acid (HA) into the NP, and 5) injury followed by both the HDC AF patch and HA NP injection. The HDC treatment was 15 mg/mL type-I collagen mixed with 0.06mM riboflavin, injected at the defect site and crosslinked in situ with blue light. The NP injection was HA modified with C16 side chains to increase the viscosity of the hydrogel (HYADD 4®)6. At 6 weeks post-operatively, sheep were sacrificed and had 3T magnetic resonance images (MRI) taken of their lumbar spine. Disc height analysis and Pfirrmann grading were performed on each segment using MR images. Additionally, quantitative MRI analyses were performed using a custom MATLAB algorithm that segments NP from the surrounding tissue and directly measures the NP volume. ANOVA with Tukey’s HSD was used to determine statistical significance between groups for disc height and quantitative MRI analyses, and the Kruskal-Wallis test with Mann-Whitney tests was used to statistically analyze Pfirrmann Grades. All animal use followed approved IACUC protocol. RESULTS/ANTICIPATED RESULTS: As shown in axial MR images (Figure 1A), intact discs had hyperintense NP with a distinct border to the AF. The discs receiving injury with no treatment had hypointense NP with no distinct border between the AF and NP. Individual and combined treatment with the HA NP injection and HDC AF patch appeared to preserve the hyperintense NP signal and AF/NP border. Intact control discs were not degenerated and had an average Pfirrmann grade of 1 (Figure 1B), while injured, untreated discs had significant degeneration with an average Pfirrmann grade of 3. Discs receiving the HA NP injection and collagen AF patch individually showed fewer signs of degeneration than the injured alone, and the combined treatment resulted in the least amount of degeneration with Pfirrmann grades not significantly different than the intact controls. Disc height index confirmed the trends seen in the Pfirrmann grades (Figure 1C), where injured discs lost 20% of the intact disc height, the individual NP and AF repairs restored 5-10% of intact disc height, and the combined repairs preserved 90% of the intact disc height. The NP voxel count of all treatment groups were similar to the intact controls (Figure 1D). DISCUSSION/SIGNIFICANCE OF IMPACT: The objective of this study was to determine how combined AF and NP can prevent degenerative changes to the disc in a large animal in vivo model. Pfirrmann grading and disc height index results show that the greatest preservation of disc morphology was seen with combined AF and NP repairs, while the individual strategies prevented degenerative changes better than injury with no treatment. It appears the HA NP injection restores lost water content to the disc following injury, and the AF collagen patch plays a role in maintaining the NP repair within the disc. This is the first study to our knowledge to attempt combined AF and NP repairs in an in vivo large animal model. Combining NP and AF repairs leads to significantly improved outcomes following disc injury, which warrants the translation of combined repairs into the clinic to improve patient outcomes with degenerative disc disease involving NP and AF.
3528 Common Mechanisms Underlying Epilepsy and Tauopathy
- Ryan Adam Cloyd, Joe Abisambra, Bret Smith
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- 26 March 2019, p. 6
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OBJECTIVES/SPECIFIC AIMS: Neurologic disorders are among the most significant health challenges facing society today. Although different neurologic disorders are often thought to be distinct from one another, evidence suggests similar processes may contribute to pathology in different diseases. Previous studies suggest that common disease mechanisms contribute to the development of epilepsy and tauopathy. The purpose of this study is to better characterize this relationship and explore potential therapeutic avenues to slow disease progress. METHODS/STUDY POPULATION: This study uses the pilocarpine-induced status epilepticus model of temporal lobe epilepsy to explore the effect of severe seizures on tau pathology. Brains were collected from mice at 6 or 24 hours after induced status epilepticus. Homogenates were analyzed via Western blot to look for changes in tau phosphorylation or activity of two major regulators of tau phosphorylation, GSK3β and PP2A. These data show that changes in tau phosphorylation dynamics occur at a much earlier time point after status epilepticus than has previously been described. RESULTS/ANTICIPATED RESULTS: GSK3β activity increased within 6 hours and remained elevated by 24 hours. PP2A activity initially decreased but returned to normal by 24 hours. These data show that changes in tau phosphorylation dynamics occur at a much earlier time point after status epilepticus than has previously been described. DISCUSSION/SIGNIFICANCE OF IMPACT: The current project supports previous observations that seizures promote tau phosphorylation in vivo, but suggests that changes begin much earlier than previously thought. Further work is needed to understand how post-seizure changes in tau phosphorylation develop over longer periods of time. Additionally, future work will characterize the effect of tauopathy on electrical activity in vivo and in vivo.
3128 Copula-Based Regression Models for Correlated Bivariate Binary Outcomes: Application to Ophthalmologic Data Structures
- Haifa Alqahtani, John Kwagyan
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- 26 March 2019, p. 7
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OBJECTIVES/SPECIFIC AIMS: To account for association between the pair of binary outcomes, we adopt the Clayton and Frank copulas to indirectly specify their joint distributions. METHODS/STUDY POPULATION: We propose a regression model for the joint modelling of correlated bivariate outcomes using copulas. RESULTS/ANTICIPATED RESULTS: develop full maximum likelihood inference.
3249 Defining the Extracellular Vesicle Content of Interstitial Fluid for Blood-Free Diagnostics; Extraction Methods and Initial Characterization
- Justin Baca Robert Taylor, Srinivasa Rao Gadam, Lauren Perez
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- 26 March 2019, p. 7
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OBJECTIVES/SPECIFIC AIMS: Recent advances in microneedle technology have enabled practical, in vivo dermal interstitial fluid (ISF) sampling. These minimally-invasive techniques allow for collection of ISF without damage to adjacent tissues and do not rely on blister formation. Initial reports of extracellular vesicle (EV) isolation from dermal ISF and paired blood samples suggest that EVs may be more abundant in ISF. Analysis of ISF-derived EVs may allow for more detailed study of intercellular communication at the tissue level, particularly in acute inflammatory conditions. The objective of this study is to describe the isolation and initial characterization of interstitial fluid-derived exosomes. METHODS/STUDY POPULATION: We apply electron microscopy, nanoparticle tracking analysis (NTA), immuochemical, and sequencing methods to describe and distinguish the EV content of interstitial fluid. We include apparently healthy adult human subjects with no active skin disease. We also study immunocompetent, CD-hairless rats to demonstrate the generalizability of the methods. RESULTS/ANTICIPATED RESULTS: We successfully isolated EVs from human and rat interstitial fluid using commercially available precipitation methods. The EVs were initially characterized using UV/Vis spectroscopy, electron microscopy, and NTA. While the study is ongoing, initial results suggest that the concentration and size distribution of EVs differs significantly between blood fractions and ISF. Further immunochemical and sequencing characterization is ongoing. DISCUSSION/SIGNIFICANCE OF IMPACT: We present here the initial characterization of EVs isolated from dermal interstitial fluid. This appears to be the first report of EV characterization using ISF collection methods that do not perturb adjacent tissues (such as with blister or microdialysis methods). The present study lays a foundation for further examination of ISF-derived EVs in acute inflammatory disease such as cellulitis or infectious neuritis. This may enable minimally invasive diagnostics and new research tools to understand intercellular communication in living organisms with increased spatial and temporal resolution.
3533 Delayed Administration Of Angiotensin Receptor (AT2R) Agonist C21 Downregulates Diabetes Induced Pro-Inflammatory Microglia Activation To Improve Cognitive & Functional Recovery Post Stroke: Therapeutic Indications For The Treatment Of Vascular Cognitive
- Ladonya Jackson, Guangkuo Dong, Susan Fagan, Adviye Ergul
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- 26 March 2019, p. 7
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OBJECTIVES/SPECIFIC AIMS: The study aim was to 1) elucidate mechanisms contributing to the evolution of PSCI using a clinically relevant model of diabetes, a major risk factor for stroke and cognitive impairment, and 2) develop angiotensin type 2 receptor (AT2R) agonism as a therapeutic target. METHODS/STUDY POPULATION: Diabetes was induced in male Wistar rats by a HFD & low dose streptozotocin combination. At 12-14 weeks of age a total of 69 control & diabetic rats were subjected to 1 hr middle cerebral artery occlusion (MCAO) or Sham surgery. 3 days post-MCAO, rats that met the pre-set inclusion criteria were administered C21 or saline in drinking water at a dose of 0.12 mg/kg/day Adhesive removal task (ART) & 2-trial Ymaze were utilized to test sensorimotor & cognitive function at baseline as well as 1, 2, 4 and 8 weeks post-stroke. At week 8 post-stroke cell suspensions from freshly harvested brains were analyzed by flow cytometry utilizing antibodies against cell surface markers for M1 (CD11b+/CD45 low/ CD86+/TNFa+), M2 (CD11b+/CD45 low/ CD206+/IL-10+), and residential microglia (CD11b+/CD45+/ TMEM119+). RESULTS/ANTICIPATED RESULTS: Control rats progressively recovered from stroke-induced functional deficits by week 8, while diabetics still remained impaired (P< 0.05). 8 weeks post-MCAO only diabetic rats exhibited a decline in sensorimotor (P< 0.05) and cognitive function (P< 0.05) compared to Shams. Delayed administration of C21 on D2 post-stroke halted the decline and improved sensorimotor (P< 0.05) and cognitive function (P< 0.01). Flow cytometric analyses indicate that 8 post-stroke vehicle diabetics had an elevated M1/M2 ratio within the ipsilateral prefrontal cortex and hippocampus (P< 0.01, 0.01). They also had a larger percentage of non-residential microglia/macrophages, indicative of compromised blood brain barrier (BBB) integrity. Treatment with C21 significantly lowered the M1/M2 ratio (P< 0.05) and improved the BBB integrity. DISCUSSION/SIGNIFICANCE OF IMPACT: Taken together this study suggests that the use of comorbid disease models such as diabetes, may allow for more translational evaluations of PSCI. Higher translational relevance may also lead to a higher number of successful clinical trials and more FDA approved stroke therapies. It also suggests that C21 may serve as a potential therapeutic to modulate the development of PSCI.
3212 Development of a Contractile Fontan Circuit to Decrease Central Venous Pressures in Single Ventricle Patients
- Margaret Rose Ferrari, Jeffrey Jacot, Michael Di Maria, Damon Pool, Mallory Lennon, Dillon Jarrell
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- 26 March 2019, pp. 7-8
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OBJECTIVES/SPECIFIC AIMS: Children born with a single ventricle congenital heart defect requires three invasive open-heart surgeries in the first three years of life. The third operation, the Fontan procedure, includes connection of the vena cava (VC) to the pulmonary artery (PA) using a bio-inert conduit to reduce work required by the right ventricle (RV). While this operation greatly extends the lives of HLHS patients, the Fontan circuit eventually fails, and the only solution is a scarcely available donor heart. This failed circuit is explained by the “Fontan paradox” where central venous pressures build up over time, causing increased systemic resistance and congestion. The absence of the sub-pulmonary ventricle leads to abnormal hemodynamics associated with life-threatening complications. We believe that decreasing central venous pressures through the use of a tissue engineered contractile, patient specific conduit will decrease the amount and severity of complications caused by the “Fontan paradox.” We will use amniotic fluid derived induced pluripotent stem cells (AF-iPSCs) differentiated into cardiomyocytes (CMs) to generate flow within a biodegradable conduit. Additionally, AF-iPSC will be differentiated into structural support cells (SSCs), including cardiac fibroblasts and epicardium. Several studies suggest advanced contraction and structure of CMs in specific ratios with SSCs, particularly mouse and human fetal fibroblasts. In combination, these cells have shown advanced tissue organization and function through mechanically and electrically aligned junctions. This allows them to have a magnitude higher contractile force than CMs alone, making them ideal for increasing pressure within a tissue engineered construct. This poster focuses on the differentiation and selection of SSCs. METHODS/STUDY POPULATION: AF-iPSCs differentiation began at roughly 80% confluency. Mesoderm formation occurred via WNT pathway modulation by supplementing RPMI+insulin media with 0.5 ng/mL BMP4 at day 0, followed by 3 ng/mL BMP4, 2 ng/mL Activin A, and 5 ng/mL BFGF for four days. Then, RPMI+insulin media was supplemented with 10 ng/mL of BMP4 until day fifteen for epicardial formation. Cells were lifted to induce epithelial-to-mesenchymal transition (EMT) and RPMI-insulin media was supplemented with 10 ng/mL BFGF for cardiac fibroblasts. They were then harvested and characterized using immunofluorescence. Planned experiments include RT-qPCR for further characterization of cardiac fibroblasts. Additionally, a fibroblast isolation plating technique will be utilized to obtain cardiac fibroblast from AF-iPSC CMs and AF-iPSC epicardium. Commercially obtained human cardiac fibroblasts will be utilized as a control for all studies. RESULTS/ANTICIPATED RESULTS: Immunofluorescence (IF) revealed positive expression of vimentin and α-SMA indicating a fibroblast and vascular smooth muscle phenotype after supplementation with 10 ng/mL of BMP4 after EMT induction. It is expected that IF of epicardial formation at day 15 will show positive expression of WT1, a well-known epicardial marker. We also suspect RT-qPCR will reveal high expression of cardiac fibroblast specific markers COL1A1, PDGFA, TCF21, and THSB1. We expect to yield a higher number of cardiac fibroblast from the small molecule AF-iPSC differentiation compared to a timed plating technique of AF-iPSC CMs and AF-iPSC epicardium (separately plated). Results will be quantified and compared using the aforementioned techniques. DISCUSSION/SIGNIFICANCE OF IMPACT: Discussion/significance of impact: Although fibroblasts make up a large portion of cells in the heart and greatly enhance CM function, they are poorly characterized in the literature and not easily obtained. This study will provide an efficiency comparison on the best method for acquiring cardiac fibroblast for cardiac tissue engineering applications as we move forward with translational cardiac pediatric research.
3444 Development of human engineered cardiac tissue (hECT)-based screening assay to explore cardiac contractile properties in response to pharmacological challenge with proarrhythmic drugs
- Francesca Stillitano, Irene C. Turnbull, Jaydev Dave, Jean-Sébastien Hulot, Roger J. Hajjar
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- Published online by Cambridge University Press:
- 26 March 2019, p. 8
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OBJECTIVES/SPECIFIC AIMS: The goals of this study were (1) to evaluate the effect of proarrhythmic drugs on calcium transient and (2) to use three-dimensional human engineered cardiac tissue (hECT) technology to evaluate cardiac contractile properties in response to pharmacological challenge with proarrhythmic drugs. METHODS/STUDY POPULATION: Calcium transient was measured in subject-specific iPSC-CMs by using the IonOptix system in Sotalol treated vs. untreated conditions. We fabricated human engineered cardiac tissues (hECT) in a custom designed bioreactor using low- and high-sentitive subject-specific iPSC-CMs. Contractile function of the hECT was evaluated at baseline and after Sotalol [300 µM] administration. The change in beat rate was recorded under spontaneous beating conditions; changes in other twitch parameters, including time to relaxation, were recorded under electrical stimulation. Time to relaxation served as an indicator of action potential duration (APD), which has a temporal correlation with the QT interval. RESULTS/ANTICIPATED RESULTS: The low-sensitive iPSC-CM showed a considerable drop in overall peak height of the calcium transient, in the presence of 100 µM Sotalol. The high-sensitive line, however, showed a more pronounced drop in peak height. Sotalol treatment also induced a more pronounced increase in the exponential decay time constant (tau) in the high-sensitive line compared to the low-sensitive line. The hECT fabricated with high sensitive hiPSC-CM showed a larger decrease in spontaneous beat rate in response to Sotalol (0.41 vs 0.23 fold decrease), with a higher increase in time to relaxation (1.8 vs 1.3 fold increase), compared to hECT from low sensitive hiPSC-CM. Moreover, while the low-sensitive hECT showed a positive correlation between time to relaxation and developed force, as expected after Sotalol stimulation; the high-sensitive hECT failed to show a positive inotropic response. DISCUSSION/SIGNIFICANCE OF IMPACT: Our findings suggest subject-specific iPSC-CMs and hECT, can be used to model functional abnormalities observed in diLQTS in response to Sotalol, and offer novel insights into human-based screening assays for toxic drug reactions. Success of this study may help identify key components underlying diLQT susceptibility to ultimately develop novel therapeutic agents.
3521 Distinct single cell gene expression in peripheral blood monocytes correlates with treatment response groups to TNF-alpha inhibition in rheumatoid arthritis
- Theresa Wampler Muskardin, Zhongbo Jin, Jessica M. Dorschner, Yogita Ghodke-Puranik, Timothy Niewold
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- Published online by Cambridge University Press:
- 26 March 2019, pp. 8-9
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OBJECTIVES/SPECIFIC AIMS: The cellular mechanisms that underlie the IFNβ/α ratio that predicts response are not known. Effects of IFN on single immune cells may be masked in whole blood or mixed cell populations. By studying the effect of IFNβ/α activity ratio on individual monocytes, we can determine the functional impact of the IFN ratio and suggest the cellular mechanisms that underlie response/non-response to TNFi therapy in RA. METHODS/STUDY POPULATION: We used single cell analysis to investigate whether monocyte gene expression differs significantly between RA patients according to their pre-TNFi serum IFN-β/α ratio. Single classical (CL) and non-classical (NC) blood-derived monocytes were isolated from 15 seropositive RA subjects prior to biologic therapy. Subjects were grouped by pre-TNFi serum IFN-β/α ratio into two groups, those with a high IFN-β/α ratio (≥1.3, n = 6) and those with a low IFN-β/α ratio (<1.3, n = 9). 87 target genes were analyzed. Genes that varied significantly between the groups by categorical analyses were tested in multivariate logistic regression models. RESULTS/ANTICIPATED RESULTS: Every participant was seropositive for rheumatoid factor and antibodies to cyclic citrullinated peptide. Among the participants in the groups, there were no significant differences in age or DAS scores (P>0.05). The treatments were comparable and none were being treated with biologic therapy. There were striking differences in monocyte gene expression between patients with pre-treatment blood IFNβ/α activity <1.3 and ≥1.3. Expression of (1) key type I IFN pathway genes (JAK1, STAT2, IFIT2, IFIH1, PRDM1); (2) IL12; (3) CD36; and (4) CTLA4 were the strongest differentiators between groups (p<0.0001 for each, corrected for multiple comparisons). DISCUSSION/SIGNIFICANCE OF IMPACT: In this study we were able to measure gene expression in single monocytes from seropositive RA patients prior to biologic treatment. Within-cell co-expression patterns demonstrate biological differences in monocytes of RA patients with an IFNβ/α ≥1.3, the ratio of type I IFNs which predicts non-response to TNFi. The data suggest that there may be differential IFN production and pathway activation in patients who do not respond to TNFi. The increased expression of CD36 in monocytes from RA patients with high IFN β/α activity may be a reflection of increased “foam cells” in the inflamed tissue of patients who do not respond to TNFi. Enrichment of CTLA4 in those with high serum IFNβ/α suggests that CTLA4-Ig may be less likely to be an effective alternative for someone who is not likely to respond to TNFi. Current work includes determining whether the peripheral blood findings reflect altered cellular composition, type I IFN production and signaling in the synovium. Significance: This work will help to develop a more individualized approach to therapy in RA and determine an immunological basis of response/non-response to TNFi.
3299 Dynamic Afterload Cardiac Microtissue Model To Examine Molecular Pathways of Heart Failure
- Abhinay Ramachandran, Carissa Livingston, Elise Corbin, Alexia Vite, Alex Bennett, Kenneth Margulies
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- 26 March 2019, p. 9
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OBJECTIVES/SPECIFIC AIMS: This project aims to determine the key molecular pathways that link increased myocardial wall stress to cardiomyocyte hypertrophy and subsequent heart failure. We will use a cardiac microtissue (CMT) model with dynamically tunable cantilever stiffness to examine changes in CMT hypertrophy and electro-mechanical properties in response to increased afterload (cantilever stiffness). Subsequently, we will determine if inhibition of pro-hypertrophic or anti-hypertrophic pathways alter the hypertrophic response to increased afterload. Primary outcomes for this study are static/dynamic force, minimum electric field strength (VT), maximum capture rate (MCR), average cell area, and tissue cross-sectional thickness, and secondary outcomes are degree of myoblast activation and apoptosis. METHODS/STUDY POPULATION: CMT platforms will be fabricated using iron-doped polydimethylsiloxane (PDMS) to create magnetically tunable cantilevers. Cantilever stiffness will be increased with the application of an external magnetic field. Cantilever stiffness will be measured using a capacitance probe, where the force required to deflect both the cantilever and calibration probe is in accordance with Hooke’s Law. Human induced pluripotent stem cell cardiomyocyte (hiPSC-CMs) will be cultured and matured as 3D CMTs. In-vitro static/dynamic force generation will also be calculated by measuring the deflection of the cantilevers and applying Hooke’s law. CMTs will be paced using carbon electrodes to obtain VT and MCR. Structural data will be obtained using immunostaining and confocal microscopy. Finally, we will use pharmacologic inhibitors to inhibit molecular pathways that we identified in prior genetic screens such as ABCC8 (anti-hypertrophic mediator) and C1QTNF9 (pro-hypertrophic mediator). We will examine each of these pathways in low- and high-stiffness conditions. RESULTS/ANTICIPATED RESULTS: We believe increased afterload will cause significant hypertrophy, measured by increases in CMT cross-sectional thickness, cardiac myocyte area, myofibroblast activation, and myocyte apoptosis. In addition, we expect to see increases in static/dynamic force, increased voltage threshold, and decreased maximum capture rate. Preliminary results show a 64.3% increase in force generation when stiffness is increased by approximately 30%, and a 44.4% decrease in force generation when stiffness is decreased by approximately 30%. Finally, we expect that inhibiting a pro- or anti-hypertrophic molecular pathway will weaken or strengthen the hypertrophic response to increased afterload, respectively. DISCUSSION/SIGNIFICANCE OF IMPACT: To our knowledge, our lab is the first to create a dynamically tunable afterload system in the cantilever CMT model. This advance provides us with a robust platform to determine the molecular pathways that cause increased myocardial wall stress to result in cardiomyocyte hypertrophy and heart failure, which remain a critical knowledge gap in our understanding of cardiovascular disease. With more precise understanding of these pathways, we will equip ourselves with the knowledge to develop novel therapeutic agents to prevent the development or progression of heart failure.