Etiopathological Study of Type 2 Diabetes Patient from India

Type 2 Diabetes (T2DM) is an endocrine disorder characterized by high blood glucose level arising from combination of insufficient insulin secretion from pancreatic β cell and insulin resistance in peripheral tissues. High dipeptidyl peptidase 4 (DPP4) activity attenuates insulin secretion from pancreatic cells by inactivating gut derived incretin hormones and interestingly incretin based therapy is one of the central treatment tools available for clinicians today. DPP4 is a type II transmembrane protein and it is released from the membrane through unknown mechanisms. Plasma DPP4 activity is often increased in metabolic diseases and associated with hyperglycaemia. We show that plasma DPP4 activity is significantly high in Indian T2DM patients. However, mechanism of DPP4 shedding in T2DM is largely unknown. This thesis shows an unknown cellular source and mechanism behind the enhance plasma DPP4 in T2DM patients. It uncovered that kallikrein-related peptidase 5 (KLK5) is the enzyme responsible for cleaving DPP4 from the surface of circulating CD4+ Th17 cells and shedding them into the plasma of T2DM patients. Similar cleavage and shedding activities were not seen in controls. Thus our study could be a potential approach for developing novel therapeutic strategies for hyperglycaemia. Increased DPP4 activity was shown to be independently associated with diabetes as well as obesity. As obesity is among the most important risk factors for the pathogenesis of T2DM, the relative contribution of obesity in T2DM with respect to DPP4 activity remains unclear. Using two different cohorts of non-diabetic and T2DM patients, this thesis shows that DPP4 activity is preferentially related with glycaemic control rather than obesity in T2DM patients. Hence, the research work underlying this thesis aims to examine the scope of therapeutic opportunities of DPP4 inhibitor in precision medicine

Neck height ratio is an important predictor of metabolic syndrome among Asian Indians

Background and Aims: The predictive potential of neck circumference (NC) based indices (a measure of upper body fat distribution) for predicting metabolic syndrome (MetS) and its components among Indians is not known. This study aimed to evaluate the role of NC and neck height ratio (NHtR) as independent predictors of MetS and its components as compared to traditional anthropometric indices. Materials and Methods: A total of 451 individuals from 867 screened individuals, 30–80 years age, without any co-morbid state who gave informed written consent underwent clinical, anthropometric, and biochemical assessment. Results: Patients with MetS in both the sexes had significantly higher NC, NHtR, glycated hemoglobin, fasting glucose, and dyslipidemia (higher triglycerides, total cholesterol/high-density lipoprotein cholesterol (HDL-C) ratio, low-density lipoprotein cholesterol/HDL-C ratio, and lower HDL-C). In both sexes, individuals in the highest tertile of NC had significantly greater central and generalized obesity, lower HDL-C, and significantly higher MetS. Receiver operating characteristic analysis revealed waist circumference (WC) to have the largest area under the curve for predicting MetS in both sexes, followed by NHtR, NC, and body mass index. NC and NHtR of >34.9 cm (sensitivity 78.6%; specificity 59.3%) and >21.17 cm/m (sensitivity 80.7% and specificity 64.6%) respectively for men and >31.25 cm (sensitivity 72.3%; specificity 64.4%) and >20.48 cm/m (sensitivity 80.4% and specificity 60%) respectively for women were the best values for identifying MetS. Increased NC and NHtR had odds ratio of 1.52 (95% confidence interval [CI]: 1.37–1.68; P< 0.001) and 1.96 (95% CI: 1.67–2.29; P< 0.001) respectively in identifying MetS. Conclusion: NC and NHtR are good predictors of MetS and cardiovascular risk factors in Asian Indians. NHtR is reliable and perhaps an even better index than NC with regards to cardiovascular risk prediction

Protocol to isolate immune cells from mouse pancreatic lymph nodes and whole pancreas for mass cytometric analyses

Summary: Investigating the immune attack on β cells is critical to understanding autoimmune diabetes. Here, we present a protocol to isolate immune cells from mouse pancreatic lymph nodes and whole pancreas, followed by mass cytometric analyses. This protocol can be used to analyze subsets of innate and adaptive immune cells that play critical roles in autoimmune diabetes, with as few as 5 × 105 cells. This protocol can also be adapted to study resident immune cells from other tissues.For complete details on the use and execution of this protocol, please refer to Piñeros et al. (2022).1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

KLK5 induces shedding of DPP4 from circulatory Th17 cells in type 2 diabetes

Objective Increasing plasma levels and activity of dipeptidyl peptidase-4 (DPP4 or CD26) are associated with rapid progression of metabolic syndrome to overt type 2 diabetes mellitus (T2DM). While DPP4 inhibitors are increasingly used as anti-hyperglycemic agents, the reason for the increase in plasma DPP4 activity in T2DM patients remains elusive. Methods We looked into the source of plasma DPP4 activity in a cohort of 135 treatment naive nonobese (BMI < 30) T2DM patients. A wide array of ex vivo, in vitro, and in silico methods were employed to study enzyme activity, gene expression, subcellular localization, protease identification, surface expression, and protein–protein interactions. Results We show that circulating immune cells, particularly CD4+ T cells, served as an important source for the increase in plasma DPP4 activity in T2DM. Moreover, we found kallikrein-related peptidase 5 (KLK5) as the enzyme responsible for cleaving DPP4 from the cell surface by directly interacting with the extracellular loop. Expression and secretion of KLK5 is induced in CD4+ T cells of T2DM patients. In addition, KLK5 shed DPP4 from circulating CD4+ T helper (Th)17 cells and shed it into the plasma of T2DM patients. Similar cleavage and shedding activities were not seen in controls. Conclusions Our study provides mechanistic insights into the molecular interaction between KLK5 and DPP4 as well as CD4+ T cell derived KLK5 mediated enzymatic cleavage of DPP4 from cell surface. Thus, our study uncovers a hitherto unknown cellular source and mechanism behind enhanced plasma DPP4 activity in T2DM. © 2017 The Author. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).1441sciescopu

Adipose recruitment and activation of plasmacytoid dendritic cells fuel metaflammation

In obese individuals the visceral adipose tissue (VAT) becomes seat of chronic low grade inflammation (metaflammation). But the mechanistic link between increased adiposity and metaflammation remains largely unclear. We report here that in obese individuals deregulation of a specific adipokine, chemerin, contributes to innate initiation of metaflammation, by recruiting circulating plasmacytoid dendritic cells (pDCs) into visceral adipose tissue via chemokine-like receptor 1 (CMKLR1). Adipose tissue-derived high mobility group B1 (HMGB1) protein, activates toll-like receptor 9 (TLR9) in the adiposerecruited pDCs by transporting extracellular DNA via receptor for advanced glycation endproducts (RAGE) and induces production of type I interferons. Type I interferons in turn help in proinflammatory polarization of adipose-resident macrophages. Interferon signature gene expression in VAT correlates with both adipose tissue and systemic insulin resistance in obese individuals, represented by ADIPO-IR and HOMA2-IR respectively, and defines two subgroups with different susceptibility to insulin resistance. Thus our study reveals a hitherto unknown pathway that drives adipose tissue inflammation and consequent insulin resistance in obesity

Inhibition of the Eukaryotic Initiation Factor-2-α Kinase PERK Decreases Risk of Autoimmune Diabetes in Mice

Disclosures: VC, MES, DS, and MJM are employees of HiberCell, Inc. SAT, RGM, and HiberCell have filed a provisional patent on compounds to inhibit PERK in type 1 diabetes. SAT and RGM received an investigator-initiated award from HiberCell, Inc. for use of PERK inhibitors in this study. KAS is a consultant for and has received research support from HiberCell, Inc. SAO is a co-founder, equity holder, and consultant for OptiKIRA, LLC.SCOPUS: ar.jinfo:eu-repo/semantics/publishe