👤 T A Glass

Type 1 diabetes (T1D) is an autoimmune disease resulting in the destruction of pancreatic β-cells leading to insulin deficiency and hyperglycemia. Single cell transcriptomic analysis of human islets demonstrated profound β-cell changes and revealed heterogeneity in endocrine and exocrine cells in T1D. Pancreatic stellate cells (PSCs), the resident mesenchymal cells of the pancreas, regulate extracellular matrix homeostasis and drive fibrosis in aging, pancreatitis, and pancreatic cancer. By secreting cytokines and growth factors, PSCs contribute to local immunity and inflammation that affect pancreatic exocrine and endocrine functions. However, cell-cell communication from single cell transcriptomics analyzing the role of PSCs in T1D has not been explored. We analyzed single-cell RNA sequencing data from human pancreatic islets of 20 donors with and without T1D from the Human Pancreas Analysis Program database using the CellChat R package, focusing on activated-PSCs (aPSCs) signaling pathways. In addition, we performed aPSCs differential expression gene and gene set enrichment analyses. CellChat analysis revealed aPSCs demonstrated major changes increasing the number and strength of cellular communications in T1D compared to control pancreata. Signaling pathways upregulated in cell-to-cell communication involving aPSCs include TGFB, FGF, CXCL, ANGPTL, and NGF, and their respective ligands TGFB1/3, FGF7, CXCL12, ANGPTL4 and NGF. In contrast, PTN signaling from aPSCs was blunted in T1D. Our study revealed novel intercellular communication signatures involving aPSCs in T1D. Identification of the changes in cellular communication between aPSCs and other cells in T1D suggest a role in T1D pathogenesis or progression which might lead to the development of novel therapeutics. Show less

White adipose tissue (WAT) expansion occurs through generation of new adipocytes from adipose progenitor cells (APC). The objective of this study was to characterize and validate a new transcriptional profile of APC. Single-cell (sc)/nuclei (sn) RNA-Seq was performed on nuclei from whole WAT (n = 20), cells from WAT stromal vascular fraction (n = 5), and cultured APC in vitro (n = 8) using ICELL8 smart-Seq technology. Additional snRNA-Seq was performed on WAT using 10x genomic platform. Pseudotime analyses and differentiation of hiPSCs was used to track the temporal patterns of novel gene signatures. Immunohistochemistry was performed to validate a new marker. A pre-adipocyte population was found across the four independent datasets that expressed known pre-adipocyte markers (ZNF423 and DLK1) in addition to genes typically associated with neurogenes (DPP10, PTRPT, CTNNA2, NRXN3, CTNNA2, PTPRD, CNTNAP2 and RBFOX1). The expression of these genes were temporally regulated with adipocyte differentiation. Immunohistochemistry analyses confirmed these pre-adipocytes are located in the neurovascular niche of WAT but are not neurons or endothelial cells. This work has defined a new transcriptional signature of pre-adipocytes in human subcutaneuous WAT that are distinct from mesencyhmal stem cell populations and represent novel targets for WAT expansion. Show less

Liver X receptor (LXR) agonism has theoretical potential for treating NAFLD/NASH, but synthetic agonists induce hyperlipidemia in preclinical models. Desmosterol, which is converted by Δ24-dehydrocholesterol reductase (DHCR24) into cholesterol, is a potent endogenous LXR agonist with anti-inflammatory properties. We aimed to investigate the effects of DHCR24 inhibition on NAFLD/NASH development. Here, by using APOE*3-Leiden. CETP mice, a well-established translational model that develops diet-induced human-like NAFLD/NASH characteristics, we report that SH42, a published DHCR24 inhibitor, markedly increases desmosterol levels in liver and plasma, reduces hepatic lipid content and the steatosis score, and decreases plasma fatty acid and cholesteryl ester concentrations. Flow cytometry showed that SH42 decreases liver inflammation by preventing Kupffer cell activation and monocyte infiltration. LXRα deficiency completely abolishes these beneficial effects of SH42. Together, the inhibition of DHCR24 by SH42 prevents diet-induced hepatic steatosis and inflammation in a strictly LXRα-dependent manner without causing hyperlipidemia. Finally, we also showed that SH42 treatment decreased liver collagen content and plasma alanine transaminase levels in an established NAFLD model. In conclusion, we anticipate that pharmacological DHCR24 inhibition may represent a novel therapeutic strategy for treatment of NAFLD/NASH. Show less

VPS13 protein family members VPS13A through VPS13C have been associated with various recessive movement disorders. We describe the first disease association of rare recessive VPS13D variants including frameshift, missense, and partial duplication mutations with a novel complex, hyperkinetic neurological disorder. The clinical features include developmental delay, a childhood onset movement disorder (chorea, dystonia, or tremor), and progressive spastic ataxia or paraparesis. Characteristic brain magnetic resonance imaging shows basal ganglia or diffuse white matter T2 hyperintensities as seen in Leigh syndrome and choreoacanthocytosis. Muscle biopsy in 1 case showed mitochondrial aggregates and lipidosis, suggesting mitochondrial dysfunction. These findings underline the importance of the VPS13 complex in neurological diseases and a possible role in mitochondrial function. Ann Neurol 2018;83:1089-1095. Show less

Metachondromatosis (MC) and hereditary multiple osteochondromas (HMO) are thought to be distinct disorders, each with characteristic x-ray and clinical features. Radiographic differences are the current mainstay of differential diagnosis. Both disorders are autosomal dominant, but the majority of patients with HMO have mutations in EXT-1 or EXT 2 genes. The genetic defect in MC is unknown, although recent studies indicate a possible identifiable mutation. The cancer risk in HMO is thought to be greater than in MC, although the small number of cases make such conjecture imprecise. The purpose of this report is to review existing literature and examine whether radiographic findings in HMO and MC can be reliable as a stand-alone means of differential diagnosis. Three members of a multi-generational family with an autosomal dominant exostosis syndrome were studied by clinical examination and complete skeletal survey. The roentgenographic characteristics of all osteochondromas were analyzed. The father underwent gene sequencing for EXT-1 and EXT-2, which revealed a novel EXT-2 mutation. Typical radiographic and clinical findings of both HMO and MC were seen throughout the family as well as in individuals. These family study findings contradict many of the long-standing clinical and x-ray diagnostic criteria for differentiating MC from HMO. The phenotypic crossover between the two conditions in this family, and results of genetic analysis, suggest that in the absence of a definitive genetic diagnosis, radiographic and clinical diagnosis of past and future cases HMO and MC may not be as reliable as previously assumed. Show less

In a genome-wide association study of Caucasian patients with juvenile idiopathic arthritis (JIA), we have previously described findings limited to autoimmunity loci shared by JIA and other diseases. The present study was undertaken to identify novel JIA-predisposing loci using genome-wide approaches. The discovery cohort consisted of Caucasian JIA cases (n = 814) and local controls (n = 658) genotyped on the Affymetrix Genome-Wide SNP 6.0 Array, along with 2,400 out-of-study controls. In a replication study, we genotyped 10 single-nucleotide polymorphisms (SNPs) in 1,744 cases and 7,010 controls from the US and Europe. Analysis within the discovery cohort provided evidence of associations at 3q13 within C3orf1 and near CD80 (rs4688011) (odds ratio [OR] 1.37, P = 1.88 × 10(-6) ) and at 10q21 near JMJD1C (rs647989 [OR 1.59, P = 6.1 × 10(-8) ], rs12411988 [OR 1.57, P = 1.16 × 10(-7) ], and rs10995450 [OR 1.31, P = 6.74 × 10(-5) ]). Meta-analysis provided further evidence of association for these 4 SNPs (P = 3.6 × 10(-7) for rs4688011, P = 4.33 × 10(-5) for rs6479891, P = 2.71 × 10(-5) for rs12411988, and P = 5.39 × 10(-5) for rs10995450). Gene expression data on 68 JIA cases and 23 local controls showed cis expression quantitative trait locus associations for C3orf1 SNP rs4688011 (P = 0.024 or P = 0.034, depending on the probe set) and JMJD1C SNPs rs6479891 and rs12411988 (P = 0.01 or P = 0.04, depending on the probe set and P = 0.008, respectively). Using a variance component liability model, it was estimated that common SNP variation accounts for approximately one-third of JIA susceptibility. Genetic association results and correlated gene expression findings provide evidence of JIA association at 3q13 and suggest novel genes as plausible candidates in disease pathology. Show less

A family-focused psychosocial intervention for stroke survivors is described and illustrated with case studies. It is designed to improve functional recovery through four specific pathways: increased knowledge, efficacy, and control through stroke education; optimized social support; increased network cohesion; and improved problem-solving abilities. Rationales for these pathways are presented and methods of implementing them discussed. Show less