Human islets expressing HNF1A variant have defective beta cell transcriptional regulatory networks

Using an integrated approach to characterize the pancreatic tissue and isolated islets from a 33-year-old with 17 years of type 1 diabetes (T1D), we found that donor islets contained beta cells without insulitis and lacked glucose-stimulated insulin secretion despite a normal insulin response to cAMP-evoked stimulation. With these unexpected findings for T1D, we sequenced the donor DNA and found a pathogenic heterozygous variant in the gene encoding hepatocyte nuclear factor-1alpha (HNF1A). In one of the first studies of human pancreatic islets with a disease-causing HNF1A variant associated with the most common form of monogenic diabetes, we found that HNF1A dysfunction leads to insulin-insufficient diabetes reminiscent of T1D by impacting the regulatory processes critical for glucose-stimulated insulin secretion and suggest a rationale for a therapeutic alternative to current treatment

Broad Repertoire of T Cell Autoreactivity Directly from Islets of Donors with Type 1 Diabetes (T1D)

Type 1 diabetes (T1D) is an autoimmune disease characterized by the infiltration of lymphocytes into the insulin-producing β-cells in the pancreas. We have isolated live T cells sorted or grown directly from the isolated, handpicked islets of human donors with T1D. We received ~500 islet equivalent EQ of variable purity (10-90%) from 12 donors with T1D (disease duration 0.42-20 years) and from seven control donors and two donors with type 2 diabetes (T2D). A total of 321 T cell lines and clones were derived from the islets of donors with T1D (3 lines from the 9 control donors). These are 131 CD4+ lines and clones, 47 CD8+ lines and 143 lines that contain both CD4+ and CD8+ T cells. From 50 lines and clones examined to date, we have determined the autoreactivity of 19 and have seen a broad repertoire of T cell autoreactivity in the islets, including characterized targets and post-translationally modified targets. Autoreactivity of CD4+ T cell lines was to three different peptides from glutamic acid decarboxylase 65 (GAD; GAD115-127, GAD274-286, GAD555-567), proinsulin76-90, and to chromogranin A or proinsulin expressed by DR4+DQ8+ B cells transduced with lentivirus containing constructs with the open reading frames corresponding to whole autoantigens. Reactivity to modified peptides included the glucose-regulated protein 78 and islet amyloid polypeptide with arginine to citrulline modifications (GRP78292-305(Arg-Cit297) and IAPP65-84(Arg-Cit 73, 81)), deaminations (IA-2545-562(Gln-Glu 548, 551, 556), and to several insulin hybrid peptides. These autoreactive CD4+ T cell lines and clones secreted only pro-inflammatory cytokines (IFN-γ, TNFα) upon peptide stimulation. For CD8+ T cells from islets, from one donor with T1D, we saw binding of a pool of HLA-A2 pentamers loaded with insulin B10-18, IA-2797-805 and insulin specific glucose-6-phosphatase catalytic subunit related protein, IGRP265-273. These results have implications for the development of successful prevention and reversal therapeutic strategies in T1D

α Cell Function and Gene Expression Are Compromised in Type 1 Diabetes.

Many patients with type 1 diabetes (T1D) have residual β cells producing small amounts of C-peptide long after disease onset but develop an inadequate glucagon response to hypoglycemia following T1D diagnosis. The features of these residual β cells and α cells in the islet endocrine compartment are largely unknown, due to the difficulty of comprehensive investigation. By studying the T1D pancreas and isolated islets, we show that remnant β cells appeared to maintain several aspects of regulated insulin secretion. However, the function of T1D α cells was markedly reduced, and these cells had alterations in transcription factors constituting α and β cell identity. In the native pancreas and after placing the T1D islets into a non-autoimmune, normoglycemic in vivo environment, there was no evidence of α-to-β cell conversion. These results suggest an explanation for the disordered T1D counterregulatory glucagon response to hypoglycemia. Cell Rep 2018 Mar 6; 22(10):2667-2676

Luxury brands consumption: The segment of “Chandlers”

The purpose of this paper is to introduce the segment of “chandlers” to the Russian academic society and to describe the specifics of their contemporary consumer behavior. The term “chandler” for this study was borrowed from American classical literature and applied to marketing. The study was conducted in April 2016 and comprised of two stages. The first stage was a series of in-depth interviews with seven representatives of the target audience from Moscow. It allowed to formulate the hypotheses which were proved/disproved by these hypotheses during the online survey. 117 relevant respondents were chosen for the study (72 — from Moscow, 45 — from regional city Ufa). The results allowed to formulate a preliminary conclusion there are no сhandlers in Ufa now. The most popular luxury brands for the Moscow сhandlers and specifics of their consumption were determined. This research is the first descriptive step to understanding the specifics of contemporary сhandlers — how they manage to consume luxury in the form of material artefacts and services, while being kept on a shoestring budget. The research entails a few limitations. The investigation comprised only a limited numbers of the respondents from Russian cities as Moscow and Ufa. In future, more consumers will be involved in the sample to cover more cities in Russia and respondents from other countries will be included. Upon the research completion a range of the recommendations has been provided to the luxury producers whose brands are already presented in Moscow and also for those who are planning to open their stores there. The results may serve as a guide for marketing tools development in the luxury industry. The originality of the paper lies in the term “chandlers’ segment” which is introduced in marketing theory for the first time

Uveo-Meningeal Syndromes: Vogt-Koyanagi-Harada (VKH) Disease

Ocular inflammatory symptoms with concurrent neuro-ophthalmologic manifestations can be diagnostically challenging. We provide a general overview of uveo-meningeal syndromes, which comprises a heterogeneous group of disorders that involve inflammation of the uveal tract, retina, and meninges. The presentation focuses on the uveomeningeal syndrome of Vogt-Koyanagi-Harada (VKH) Disease by providing a comprehensive overview of diagnostic criteria, pathogenesis, clinical course, and management. To demonstrate the heterogeneous clinical presentations and possible neuro-ophthalmological manifestations that can challenge diagnosis, we chronicle three cases of VKH seen at our institution and highlight the diagnostic work-up, management, and outcomes. This presentation summarizes a practical strategy for approaching the clinical heterogeneity of VKH.[1] Brazis PW, Stewart M, Lee A. The Uveo-Meningeal Syndromes. The Neurologist 2004, 10(4):171-184; [2] Tsuboyama M, Chandler JV, Scharf E, et al. Neurologic Complications of Acute Posterior Multifocal Placoid Pigment Epitheliopathy: A Case Series of 4 Patients. Neurohospitalist 2018; 8(3):146-151.; [3] Allegri P, Risotto R, Herbort CP, Murialdo U. CNS Disease and Uveitis. J Ophthalmic Vis Res. 2011; 6(4): 284-308.; [4] Lavezzo MM, Sakata VM, et al. Vogt-Koyanagi-Harada disease: review of a rare autoimmune disease targeting antigens of melanocytes. Ophanet Journal of Rare Diseases. 2016; 11: 29; [5] Read RW, Rao NA: Utility of existing Vogt-Koyanagi-Harada syndrome diagnostic criteria at initial evaluation of the individual patient: a retrospective analysis. Ocul Immunol Inflamm 2000; 8: pp. 227-234.; [6] Read RW, Rao NA, Cunningham ET. Vogt-Koyanagi-Harada Disease. Curr Opin Ophthal. 2000; 11(6):437-442; [7] Read RW, Holland GN, Rao NA, et. al.: Revised diagnostic criteria for Vogt-Koyanagi-Harada disease: report of an international committee on nomenclature. Am J Ophthalmol 2001; 131: pp. 647-652.; [8] Goto, Rao, and Rao. Ryan's Retina 7th Edition 2022; 76, 1577-1589; [9] Feldman BH, O'Keefe GD, Salcedo HR, et al. Vogt-Koyanagi-Harada Disease. Eyewiki 2023. https://eyewiki.aao.org/Vogt-Koyanagi-Harada_Disease; [10] Dogan B, Erol MK, Cengiz A. Vogt-Koyanagi-Harada disease following BCG vaccination and tuberculosis. Springerplus. 2016; 5: 603; [11] Ferriera FT, Araujo DC, et al. Possible Association between Vogt-Koyanagi-Harada Disease and Coronavirus Disease Vaccine: A report for Four Cases. Ocul Immunol Inflamm. 2022; 1-7; [12] Rao NA, Gupta A, Dustin L, et al. Frequency of distinguishing clinical features in Vogt-Koyanagi-Harada disease. Ophthalmology 2010;117:591-9; [13] Weisz JM, Holland GN, Roer LN, et. al.: Association between Vogt-Koyanagi-Harada syndrome and HLA-DR1 and DR4 in Hispanic patients living in Southern California. Ophthalmology 1995; 102: pp. 1012-1015.; [14] Shi T, Lv W, Zhang L, Chen J, Chen H. Association of HLA-DR4/HLA-DRB1*04 with Vogt-Koyanagi-Harada disease: a systematic review and meta-analysis. Sci Rep. 2014 Nov 10;4:6887

A workshop on leadership for senior MD–PhD students

Leadership skills are essential for a successful career as a physician-scientist, yet many MD–PhD training programs do not offer formal training in leadership. The Vanderbilt Medical Scientist Training Program (MSTP) previously established a 2-day leadership workshop that has been held biennially since 2006 for students in the first and second years of the graduate school portion of combined MD and PhD training (G1/G2 students). Workshop attendees have consistently rated this workshop as a highly effective experience. However, opportunities for structured training in leadership competencies during the subsequent 3–5 years of MD–PhD training are limited. Given the success of the G1/G2 leadership workshop and the need for continuity in this model of leadership training, we developed a half-day workshop for MSTP students in the clinical years of medical school (M3/M4 students) to foster continued training in leadership. Our workshop curriculum, based in part on original cases drafted by Vanderbilt MSTP students, provides concrete strategies to manage conflict and navigate leadership transitions in the physician-scientist career path. The curriculum emphasizes both short-term competencies, such as effective participation as a member of a clinical team, and long-term competencies, such as leadership of a research team, division, or department. Our inaugural senior leadership workshop, held in August, 2015, was judged by student participants to be well organized and highly relevant to leadership concepts and skills. It will be offered biennially in our training curriculum for M3 and M4 MSTP students

“Examining How the MAFB Transcription Factor Affects Islet β Cell Function Postnatally”

The sustained expression of the MAFB transcription factor in human islet β-cells represents a distinct difference in mice. Moreover, mRNA expression of closely related and islet β-cell-enriched MAFA does not peak in humans until after 9 years of age. We show that the MAFA protein also is weakly produced within the juvenile human islet β-cell population and that MafB expression is postnatally restricted in mouse β-cells by de novo DNA methylation. To gain insight into how MAFB affects human β-cells, we developed a mouse model to ectopically express MafB in adult mouse β-cells using MafA transcriptional control sequences. Coexpression of MafB with MafA had no overt impact on mouse β-cells, suggesting that the human adult β-cell MAFA/MAFB heterodimer is functionally equivalent to the mouse MafA homodimer. However, MafB alone was unable to rescue the islet β-cell defects in a mouse mutant lacking MafA in β-cells. Of note, transgenic production of MafB in β-cells elevated tryptophan hydroxylase 1 mRNA production during pregnancy, which drives the serotonin biosynthesis critical for adaptive maternal β-cell responses. Together, these studies provide novel insight into the role of MAFB in human islet β-cells

Human pseudoislet system enables detection of differences in G-protein-coupled-receptor signaling pathways between α and β cells

SUMMARY G-protein-coupled-receptors (GPCRs) modulate insulin secretion from β cells and glucagon secretion from α cells. Here, we developed an integrated approach to study the function of primary human islet cells using genetically modified pseudoislets that resemble native islets across multiple parameters. We studied the G i and G q GPCR pathways by expressing the designer receptors exclusively activated by designer drugs (DREADDs) hM4Di or hM3Dq. Activation of G i signaling reduced insulin and glucagon secretion, while activation of G q signaling stimulated glucagon secretion but had both stimulatory and inhibitory effects on insulin secretion. Further, we developed a microperifusion system that allowed synchronous acquisition of GCaMP6f biosensor signal and hormone secretory profiles and showed that the dual effects for G q signaling occur through changes in intracellular Ca 2+ . By combining pseudoislets with a microfluidic system, we co-registered intracellular signaling dynamics and hormone secretion and demonstrated differences in GPCR signaling pathways between human β and α cells