Genome-wide association studies in human type 2 diabetes (T2D) have renewed interest in the pancreatic islet as a contributor to T2D risk. Chronic low-grade inflammation resulting from obesity is a risk factor for T2D and a possible trigger of β-cell failure. In this study, microarray data were collected from mouse islets after overnight treatment with cytokines at concentrations consistent with the chronic low-grade inflammation in T2D. Genes with a cytokine-induced change of >2-fold were then examined for associations between single nucleotide polymorphisms and the acute insulin response to glucose (AIRg) using data from the Genetics Underlying Diabetes in Hispanics (GUARDIAN) Consortium. Significant evidence of association was found between AIRg and single nucleotide polymorphisms in Arap3 (5q31.3), F13a1 (6p25.3), Klhl6 (3q27.1), Nid1 (1q42.3), Pamr1 (11p13), Ripk2 (8q21.3), and Steap4 (7q21.12). To assess the potential relevance to islet function, mouse islets were exposed to conditions modeling low-grade inflammation, mitochondrial stress, endoplasmic reticulum (ER) stress, glucotoxicity, and lipotoxicity. RT-PCR revealed that one or more forms of stress significantly altered expression levels of all genes except Arap3. Thapsigargin-induced ER stress up-regulated both Pamr1 and Klhl6. Three genes confirmed microarray predictions of significant cytokine sensitivity: F13a1 was down-regulated 3.3-fold by cytokines, Ripk2 was up-regulated 1.5- to 3-fold by all stressors, and Steap4 was profoundly cytokine sensitive (167-fold up-regulation). Three genes were thus closely associated with low-grade inflammation in murine islets and also with a marker for islet function (AIRg) in a diabetes-prone human population. This islet-targeted genome-wide association scan identified several previously unrecognized candidate genes related to islet dysfunction during the development of T2D.

Activation of oncogenic KRAS is the most common driving event in lung adenocarcinoma development. Despite the existing rationale for targeting activated KRAS and its downstream effectors, the failure of clinical trials to date indicates that the mechanism of KRAS-driven malignancy remains poorly understood. Here we report that histone deacetylase 10 (HDAC10) might function as a putative tumor suppressor in mice carrying a spontaneously activated oncogenic Kras allele. Hdac10 deletion accelerated KRAS-driven early-onset lung adenocarcinomas, increased macrophage infiltration in the tumor microenvironment, and shortened survival time in mice. Highly tumorigenic and stem-like lung adenocarcinoma cells were increased in Hdac10-deleted tumors compared with Hdac10 wild-type tumors. HDAC10 regulated the stem-like properties of KRAS-expressing tumor cells by targeting SOX9. Expression of SOX9 was significantly increased in Hdac10-deleted tumor cells and depletion of SOX9 in Hdac10 knockout (KO) lung adenocarcinoma cells inhibited growth of tumorspheres. The genes associated with TGFb pathway were enriched in Hdac10 KO tumor cells, and activation of TGFb signaling contributed to SOX9 induction in Hdac10 KO lung adenocarcinoma cells. Overall, our study evaluates the functions and mechanisms of action of HDAC10 in lung carcinogenesis that will inform the rationale for targeting its related regulatory signaling as an anticancer strategy.Significance: These findings linking HDAC10 and lung tumorigenesis identify potential novel strategies for targeting HDAC10 as a treatment for lung cancer.

In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca2+]i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca2+]i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48-hours to a variety of stressors: cytokines (low-grade inflammation), 28mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca2+]i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca2+]i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3-to-11mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca2+]i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11mM:3mM glucose) observed for FFAs and also for 28G. We also clamped [Ca2+]i using 30mM KCl + 250uM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3-to-11mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca2+]i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca2+]i but not conventional insulin secretion and ‘metabolic’ stressors (FFAs, 28G, rotenone) impacted insulin secretion.

Poly(A)-specific ribonuclease (PARN) is a 3’ exoribonuclease that plays an important role in regulating the stability and maturation of RNAs. Recently, PARN has been found to regulate the maturation of the human telomerase RNA component (hTR), a non-coding RNA required for telomere elongation. Specifically, PARN cleaves the 3’ end of immature, polyadenylated hTR to form the mature, non-polyadenylated template. Despite PARN’s critical role in mediating telomere maintenance, little is known about how PARN’s function is regulated by post-translational modifications. In this study, using shRNA- and CRISPR/Cas9-mediated gene silencing and knockout approaches, along with 3′ exoribonuclease activity assays and additional biochemical methods, we examined whether PARN is post-translationally modified by acetylation and what effect acetylation has on PARN’s activity. We found PARN is primarily acetylated by the acetyltransferase p300 at Lys-566 and deacetylated by sirtuin1 (SIRT1). We also revealed how acetylation of PARN can decrease its enzymatic activity both in vitro, using a synthetic RNA probe, and in vivo, by quantifying endogenous levels of adenylated hTR. Furthermore, we also found that SIRT1 can regulate levels of adenylated hTR through PARN. The findings of our study uncover a mechanism by which PARN acetylation and deacetylation regulate its enzymatic activity as well as levels of mature hTR. Thus, PARN’s acetylation status may play a role in regulating telomere length.

Objectives To evaluate the pharmacokinetics and microbiodistribution of 64Cu-labeled collagen binding peptides. Method The affinity constant (KD), association (ka) and dissociation rate constant (kd) for the peptide collagelin or its analogue (named CRPA) binding to collagen were measured by bio-layer interferometric analysis. Rats (n = 4–5) with myocardial infarction or normal were injected IV with the 64Cu-labeled peptides or 64Cu-DOTA as a control. Dynamic PET imaging was performed for 60 min at 7- to 8-week post-infarct. [18F]FDG PET imaging was performed to identify the viable myocardium. To validate the PET images, slices of heart samples from the base to the apex were analyzed using autoradiography and histology. Result The peptides bound to collagen with KD of ~ 0.9 μM. The 64Cu-peptides and 64Cu-DOTA accumulated in the infarct area (confirmed by autoradiography and histology images) within 1 minute of injection and were excreted rapidly via the renal system. The blood clearance curves were bi-phasic with the elimination half-lives, 21.9 ± 2.4, 26.2 ± 4.6 and 21.2 ± 2.1 min for 64Cu-CRPA, 64Cu-collagelin and the control 64Cu-DOTA, respectively. The clearance half-lives from the focal fibrotic tissue (24.1 ± 1.5, 25.6 ± 8.0 and 21.4 ± 1.3 min, respectively) and remote myocardium (20.8 ± 0.7, 21.0 ± 5.5 and 19.1 ± 2.4 min, respectively) were not significantly different. The uptake ratios of infarct-to-remote myocardium (1.93 ± 0.18, 2.15 ± 0.38 and 1.88 ± 0.08, respectively) for 64Cu-CRPA, 64Cu-collagelin and 64Cu-DOTA remained stable for the time period between 10 to 60 min. Conclusion The distribution of the 64Cu-collagelin probes corresponds to the heterogeneous distribution of expanded extracellular space in the setting of myocardial infarction. The overall washout rate from the fibrous tissue was determined by the slow washout rate (t1/2, ≥ 20 min) of the peptides from the extracellular space to the vasculature, not by the dissociation rate (t1/2, ≤ 2 min) of the 64Cu-peptides from collagen.