Project description:The decreasing numbers of Donation after Brain Death (DBD) donors necessitates the comprehensive evaluation of Donation after Cardiac Death Donors (DCD) as a source of pancreata. The aim of this study was to characterize pancreata and islets from DCD and DBD donors with respect to markers of cellular stress that may indicate compromised islet quality. Immunohistochemical staining of pre-isolation pancreas biopsies found increased numbers of caspase 3 positive islets in DBD, while markers of oxidative stress (nitrotyrosine, CML, and HNE) were elevated in DCD. Assessment of islet quality by standard (yield, morphology, fluorescence microscopy, and glucose stimulated insulin secretion) and novel methods (flow cytometry, HPLC quantification of ATP) did not reveal significant differences. However, the post culture loss of DCD islets was increased compared to DBD, and DCD islets showed delayed functional potency when transplanted into diabetic NOD.scid mice. Microarray analysis of cultured islets showed increased expression of multiple stress pathway related genes in DCD compared to DBD. Together these data indicate that the current standard donor management, pancreas recovery and preservation practices are insufficient to quench the oxidative stress injury suffered by DCD islets which leads to loss in culture and may complicate their use in clinical transplant. Keywords: cell type comparison
Project description:Expression profiling using the UPenn Mouse PancChip 5.0 was used to elucidate the genetic mechanisms of PANDER-induced cell death in pancreatic islets. Murine islets were treated with PANDER (PANcreatic DERived factor) for 48 or 72 h (n=4 and n=3 respectively). Following linear amplification, the RNA was matched for purity using Quantitative PCR.
Project description:Ex vivo lung perfusion restores normothermia, ventilation and circulation to donor lungs, typically after a period of cold ischemia. This allows donor lungs to be evaluated prior to transplantation. We used microarrays to study the biological response of human lungs to Ex Vivo Lung Perfusion. Samples were collected from donor lungs at Toronto General Hospital. Lungs were donation after brain death (DBD)
Project description:Purpose: Myt3 is a putative pro-survival factor in pancreatic islets and is expressed from E18.5 onwards. The genes that Myt3 regulates and its role in islet-cell development, function and survival are not fully known. The purpose of this study was to determine the changes in gene expression following the suppression or over-expression of Myt3 to identify possible pathways that may be regulated by Myt3. Methods: Pancreatic islets were isolated from both male and female C57/B6 mice by collagenase digestion and were picked by hand. Hand-picked islets were plated onto 804G, a complete extracellular-matrix (ECM) produced by a rat bladder carcinoma cell line, treated tissue culture dishes and transduced with 1x106 pfu virus overnight. The next day media was changed to fresh RPMI and islets were cultured for 7 days. At the end of the culture period islets were dispersed and FACs sorted for GFP+ cells. Sorted cells from at least 5 experiments were pooled and RNA was isolated using Trizol reagent. 800ng of RNA was used in the Illumina TruSeq kit for library preparation. Results: Comparison of gene expression levels between control-transduced islets and either shMyt3- or Myt3-transduced islets resulted in the identification of 51 and 89 significantly altered genes respectively. Conclusions: Our study represents the first comprehensive analysis of genes that are potentially regulated by Myt3 and highlight potential pathways that are likely important for mediating Myt3's effects of islet development, function and survival. Isolated islets were transduced with adenoviruses, cultured for 7 days on ECM and FACS sorted. Cells from up to 5 experiments were pooled and sequenced.
Project description:We have used RNA-seq to identify transcripts expressed in human islets harboring beta cells transduced to overexpress STX4 and induce chemokine ligand by adenoviral transduction
Project description:Purpose: Myt3 is a putative pro-survival factor in pancreatic islets and is expressed from E18.5 onwards. The genes that Myt3 regulates and its role in islet-cell development, function and survival are not fully known. The purpose of this study was to determine the changes in gene expression following the suppression or over-expression of Myt3 to identify possible pathways that may be regulated by Myt3. Methods: Pancreatic islets were isolated from both male and female C57/B6 mice by collagenase digestion and were picked by hand. Hand-picked islets were plated onto 804G, a complete extracellular-matrix (ECM) produced by a rat bladder carcinoma cell line, treated tissue culture dishes and transduced with 1x106 pfu virus overnight. The next day media was changed to fresh RPMI and islets were cultured for 7 days. At the end of the culture period islets were dispersed and FACs sorted for GFP+ cells. Sorted cells from at least 5 experiments were pooled and RNA was isolated using Trizol reagent. 800ng of RNA was used in the Illumina TruSeq kit for library preparation. Results: Comparison of gene expression levels between control-transduced islets and either shMyt3- or Myt3-transduced islets resulted in the identification of 51 and 89 significantly altered genes respectively. Conclusions: Our study represents the first comprehensive analysis of genes that are potentially regulated by Myt3 and highlight potential pathways that are likely important for mediating Myt3's effects of islet development, function and survival.
Project description:Biomarkers capable of monitoring β cell stress during the evolution of type 1 diabetes (T1D) are currently lacking. MicroRNAs (miRNAs) are a class of small non-coding RNAs ~22 nucleotides in length that modulate gene expression by binding to the 3’untranslated region of target mRNAs. Given their stability in biological fluids and enrichment in cell-derived EVs, we hypothesized that miRNAs from human islet and islet-derived EVs could identify β-cell stress/death and be leveraged in T1D biomarker strategies. To test this, human islets were obtained from 10 cadaveric donors (5 male/5 female) and treated with or without cytokines (IL-1β and IFN-γ) for 24 hrs, as an ex vivo model of T1D. Small RNA sequencing was performed and identified 1110 and 890 miRNAs in total and 20 and 14 differentially expressed (DE) miRNAs (fold change≥1.5 and p<0.05) from islets and EVs, respectively. These findings were validated in an independent set of cytokine-treated islets and islet-derived EVs (7M and 5F donors). Interestingly, miRNA expression pattern was strikingly different between male and female donors at baseline and under cytokine stress with < 10% overlap among the DE miRNAs. miR-155-5p and miR-146a-5p were the only two miRNAs that were upregulated in cytokine-treated islets and EVs in both the sexes. Functional enrichment analysis of DE miRNAs identified pathways such as insulin signaling, ER stress and apoptosis. Taken together, these data suggest that miRNA expression patterns change dynamically in both human islets and islet-derived EVs in response to pro-inflammatory cytokine stress. EV miRNAs were largely distinct from those in the islet fraction, suggesting that miRNAs are selectively packaged into EVs in response to extrinsic cues. Finally, these data highlight the importance of considering sex as a biological variable when defining T1D biomarkers.
Project description:We single cell sequenced multiplexed primary human islets treated ex vivo with ER and inflammatory chemicals, indexed cell type specific stress responses, found genes to regulate in SC-islets to reduce apoptosis. We conducted multiomic ATAC+RNA sequencing on human islets treated with BFA, DMSO, IL1B+IFNG+TNFa, or PBS