Project description:Type 1 diabetes (T1D) is characterized by immune mediated destruction of insulin producing β cells. Biomarkers capable of identifying T1D risk and dissecting disease-related heterogeneity represent an unmet clinical need. Aims: Towards the goal of informing T1D biomarker strategies, we profiled different classes of RNAs in human islet-derived exosomes and identified RNAs that were differentially expressed under cytokine stress conditions. Human pancreatic islets were obtained from cadaveric donors and treated with/without IL-1β and IFN-γ to mimic the pro-inflammatory T1D milieu. Total RNA and small RNA sequencing were performed to identify long (mRNA and long non-coding RNAs) and different classes of small non-coding RNAs. RNAs with fold change ≥ 1.3 and p-value < 0.05 were considered as differentially expressed. mRNAs and miRNAs species represented the most abundant long and small RNA species, respectively. Expression patterns of each class of RNA were changed with cytokine treatment. Differentially expressed long RNAs and targets of small non-coding RNAs were predicted to be involved in insulin secretion, calcium signaling, necrosis and apoptosis. Our data provides the first comprehensive catalog of protein coding and non-coding RNAs in human islet-derived exosomes and identifies RNAs that are dysregulated under cytokine stress.
Project description:Androgen receptor (AR) plays an essential role in normal prostate development and prostate cancer (PCa) progression. To understand the role of AR at the single-cell level, we performed single-cell transcriptome analysis on PCa cells stimulated with androgen and antiandrogen to reconstruct the dynamic and direct AR transcriptional network. Our work reveals that androgen stimulates the ER and Golgi stress response , promoting secreting protein trafficking, and inhibiting cell apoptosis. Moreover, we identify an ER-to-Golgi protein vesicle-mediated transport gene signature essential for maximal androgen-mediated ER-Golgi trafficking, cell proliferation, and association with PCa prognosis and progression. Notably, we show that AR collaborates with CREB3L2, XXX, to coordinately promote ER-Golgi trafficking of Golgi enzyme Mannosidase II and PCa cell survival. Finally, we show the inhibition of the ER-Golgi transport process with Brefeldin A leads to tumor regression. Our study collectively reveals the heterogeneity of PCa cell transcriptional response to androgen stimulation, demonstrates a functional role for increased ER-Golgi trafficking process, and provides a mechanism for how the process is augmented in PCa as well as the potential of targeting may provide novel treatment strategies.
Project description:We explore the transcriptional response of mammalian cells undergoing various insults to Golgi homeostasis. HEK293 cells (Flp-In T-REx 293 cells) stably containing a doxycycline-inducible Golgi-localized HaloTag2 construct (GA-HT2) were treated with the ionophore nigericin, the glycosylation inhibitor xyloside, or were induced by doxycycline and treated with the hydrophobic tag HyT36 to induce destabilization of GA-HT2. We found that while nigericin and xyloside induce global transcriptional changes, destabilization of GA-HT2 induces a Golgi-specific response.
Project description:Impaired proinsulin processing is observed in both type 1 and type 2 diabetes. We have previously shown that reductions in endoplasmic reticulum (ER) calcium (Ca2+) in the pancreatic β cell arising from impaired activity of the Sarcoendoplasmic Reticulum Ca2+ ATPase (SERCA) pump are associated with increased proinsulin secretion. However, the mechanisms responsible for reduced proinsulin processing in the context of SERCA2 deficiency remain incompletely understood. To test this, we developed mice with β cell specific SERCA2 deletion (βS2KO mice) and S2KO INS1 cells. βS2KO mice exhibited age-dependent glucose intolerance and reduced glucose-stimulated insulin secretion without evidence of impaired insulin sensitivity. ER Ca2+ levels in islets from βS2KO mice were significantly reduced, while serum proinsulin/insulin (PI/I) ratios and whole pancreas PI/I content were elevated. Immunoblot analysis of βS2KO islets and S2KO INS-1 cells revealed reduced active forms of the proinsulin processing enzymes, PC1/3, PC2 and CPE. Restoration of SERCA2b via adenoviral transduction in S2KO INS1 cells was sufficient to restore PC1/3 and PC2 maturation and enzyme activity. Brefeldin A treatment in INS1 cells recapitulated the impairments in PC1/3 and PC2 maturation observed in S2KO cells, suggesting a disturbance in protein trafficking between the ER and Golgi. Consistent with this, trafficking assays were performed using a vesicular stomatitis virus G (VSVG) protein construct and revealed a significantly slower rate of VSVG movement from the ER to the Golgi in S2KO INS1 cells. Moreover, pancreas sections from βS2KO mice showed increased co-localization of proinsulin and ProPC2 in the early compartments of the secretory pathway. Taken together, these data suggest that loss of SERCA2 activity and ER Ca2+ loss in the pancreatic β cell leads to impaired proinsulin processing via reduced maturation and trafficking of proinsulin processing enzymes.
Project description:We report the application of RNA-seq for profiling gene transcription upon treatment of methyl bestatin (MeBs, aminopeptidase inhibitor) or brefeldin A (BFA, ER-to-Golgi transport inhibitor), compared to DMSO control. We found MeBs and BFA similarly upregulated genes pertinent to proteotoxic stress.
Project description:To investigate the effects of the Golgi disruptor on liver cancer cells, we explored a global gene expression of HepG2 cells after treatment with Brefeldin A.
Project description:Purpose: To gain further mechanistic insight into phenotypic differences between wild type pancreatic islets and islets with loss of function of 4 Box C/D snoRNAs from the Rpl13a locus (U32a, U33, U34 and U35a). Methods:High quality total RNA (RIN ≥ 8.5) was prepared from hand-picked islets (n = 4 mice/genotype) using TRIZOL reagent, treated with Turbo DNAse (Thermo Fisher), and used to prepare SeqPlex RNAseq libraries (Sigma). Sequencing was performed by the Washington University Genome Technology Access Center using two lanes of Illumina HiSeq 2500, 1x50. Reads were demultiplexed and trimmed, and STAR alignment and quantification analysis was carried out using the Partek Flow platform. Uniquely aligned reads were quantified to identify genes with at least a two-fold change between genotypes with p < 0.05 and FDR step-up of 0.05. Results:We observed 2-fold or greater differences in the expression of only six genes. Conclusions: Our data indicate that loss-of-function of snoRNAs from the Rpl13a locus is associated with modest changes in mRNA abundance.
Project description:The pancreas islets RNA expressions were compared between WT (exon2 floxed) mice and Cdh13 KO (exon2 deleted) mice. The islets were isolated from the mice at 8wks old, 14wks old under normal chow diet, and 14wks old under HFD conditions.