Retinoic Acid Pathway Inhibition to Expand Human Hematopoietic Progenitor Cells with Islet Regenerative Capacity

Cellular therapy to induce islet regeneration is emerging as a novel treatment strategy for diabetes. Umbilical cord blood (UCB)-derived hematopoietic stem/progenitor cells (HSPC) isolated by high aldehyde dehydrogenase activity (ALDHhi) reduce hyperglycemia after transplantation into streptozotocin (STZ)-treated NOD/SCID mice. However, UCB-derived ALDHhi cells are rare and expansion without the loss of regenerative function is required. We hypothesized that BMS 493, an inverse retinoic acid receptor agonist, will prevent HSPC differentiation of HSPC during expansion, generating more ALDHhi cells for therapy. ALDHhi cells expanded for 6 days with BMS 493 showed a 2.70-fold-increase in ALDHhi cells compared to untreated cells. Conditioned media from BMS 493-treated cells also increased human ß-cell proliferation in vitro. However, intrapancreatic transplantation of BMS 493-treated cells did not reduce hyperglycemia in STZ-treated NOD/SCID mice. Further characterization of HSPC expansion without differentiation is required for islet regenerative therapies

Human Multipotent Stromal Cell Secreted Effectors Accelerate Islet Regeneration

Human multipotent stromal cells (hMSC) can induce islet regeneration after transplantation via the secretion of proteins that establish an islet regenerative niche. However, the identity of hMSC-secreted signals and the mechanisms by which pancreatic islet regeneration is induced remain unknown. Recently, mammalian pancreatic α-cells have been shown to possess considerable plasticity, and differentiate into β-like cells after near complete β-cell loss or overexpression of key transcriptional regulators. These studies have generated new excitement that islet regeneration during diabetes may be possible if we can identify clinically applicable stimuli to modulate these key regulatory pathways. Herein, we demonstrate that intrapancreatic-injection of concentrated hMSC-conditioned media (CM) stimulated islet regeneration without requiring cell transfer. hMSC CM-injection significantly reduced hyperglycemia, increased circulating serum insulin concentration, and improved glucose tolerance in streptozotocin-treated mice. The rate and extent of endogenous β-cell mass recovery was dependent on total protein dose administered and was further augmented by the activation of Wnt-signaling using GSK3-inhibition during CM generation. Intrapancreatic hMSC CM-injection immediately set in motion a cascade of regenerative events that included the emergence of proliferating insulin + clusters adjacent to ducts, NKX6.1 expression in glucagon + cells at days 1–4 suggesting the acquisition of β-cell phenotype by α-cells, and accelerated β-cell maturation with increased MAFA-expression for \u3e1 month postinjection. Discovery and validation of islet regenerative hMSC-secreted protein may lead to the development of cell-free regenerative therapies able to tip the balance in favor of β-cell regeneration versus destruction during diabetes. Stem Cells 2019;37:516–528

Identification of plasma lipid biomarkers for prostate cancer by lipidomics and bioinformatics

Background: Lipids have critical functions in cellular energy storage, structure and signaling. Many individual lipid molecules have been associated with the evolution of prostate cancer; however, none of them has been approved to be used as a biomarker. The aim of this study is to identify lipid molecules from hundreds plasma apparent lipid species as biomarkers for diagnosis of prostate cancer. Methodology/Principal Findings: Using lipidomics, lipid profiling of 390 individual apparent lipid species was performed on 141 plasma samples from 105 patients with prostate cancer and 36 male controls. High throughput data generated from lipidomics were analyzed using bioinformatic and statistical methods. From 390 apparent lipid species, 35 species were demonstrated to have potential in differentiation of prostate cancer. Within the 35 species, 12 were identified as individual plasma lipid biomarkers for diagnosis of prostate cancer with a sensitivity above 80%, specificity above 50% and accuracy above 80%. Using top 15 of 35 potential biomarkers together increased predictive power dramatically in diagnosis of prostate cancer with a sensitivity of 93.6%, specificity of 90.1% and accuracy of 97.3%. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) demonstrated that patient and control populations were visually separated by identified lipid biomarkers. RandomForest and 10-fold cross validation analyses demonstrated that the identified lipid biomarkers were able to predict unknown populations accurately, and this was not influenced by patient's age and race. Three out of 13 lipid classes, phosphatidylethanolamine (PE), ether-linked phosphatidylethanolamine (ePE) and ether-linked phosphatidylcholine (ePC) could be considered as biomarkers in diagnosis of prostate cancer. Conclusions/Significance: Using lipidomics and bioinformatic and statistical methods, we have identified a few out of hundreds plasma apparent lipid molecular species as biomarkers for diagnosis of prostate cancer with a high sensitivity, specificity and accuracy

Type 1 diabetes risk genes mediate pancreatic beta cell survival in response to proinflammatory cytokines

Publisher Copyright: © 2022We combined functional genomics and human genetics to investigate processes that affect type 1 diabetes (T1D) risk by mediating beta cell survival in response to proinflammatory cytokines. We mapped 38,931 cytokine-responsive candidate cis-regulatory elements (cCREs) in beta cells using ATAC-seq and snATAC-seq and linked them to target genes using co-accessibility and HiChIP. Using a genome-wide CRISPR screen in EndoC-βH1 cells, we identified 867 genes affecting cytokine-induced survival, and genes promoting survival and up-regulated in cytokines were enriched at T1D risk loci. Using SNP-SELEX, we identified 2,229 variants in cytokine-responsive cCREs altering transcription factor (TF) binding, and variants altering binding of TFs regulating stress, inflammation, and apoptosis were enriched for T1D risk. At the 16p13 locus, a fine-mapped T1D variant altering TF binding in a cytokine-induced cCRE interacted with SOCS1, which promoted survival in cytokine exposure. Our findings reveal processes and genes acting in beta cells during inflammation that modulate T1D risk.Peer reviewe

An Integrated Map of Cell Type-Specific Gene Expression in Pancreatic Islets.

Pancreatic islets consist of multiple cell types that produce hormones required for glucose homeostasis, and islet dysfunction is a major factor in type 1 and type 2 diabetes. Numerous studies have assessed transcription across individual cell types using single-cell assays; however, there is no canonical reference of gene expression in islet cell types that is also easily accessible for researchers to query and use in bioinformatics pipelines. Here we present an integrated map of islet cell type-specific gene expression from 192,203 cells from single-cell RNA sequencing of 65 donors without diabetes, donors who were type 1 diabetes autoantibody positive, donors with type 1 diabetes, and donors with type 2 diabetes from the Human Pancreas Analysis Program. We identified 10 distinct cell types, annotated subpopulations of several cell types, and defined cell type-specific marker genes. We tested differential expression within each cell type across disease states and identified 1,701 genes with significant changes in expression, with most changes observed in β-cells from donors with type 1 diabetes. To facilitate user interaction, we provide several single-cell visualization and reference mapping tools, as well as the open-access analytical pipelines used to create this reference. The results will serve as a valuable resource to investigators studying islet biology

Type 1 diabetes risk genes mediate pancreatic beta cell survival in response to proinflammatory cytokines

Publisher Copyright: © 2022We combined functional genomics and human genetics to investigate processes that affect type 1 diabetes (T1D) risk by mediating beta cell survival in response to proinflammatory cytokines. We mapped 38,931 cytokine-responsive candidate cis-regulatory elements (cCREs) in beta cells using ATAC-seq and snATAC-seq and linked them to target genes using co-accessibility and HiChIP. Using a genome-wide CRISPR screen in EndoC-βH1 cells, we identified 867 genes affecting cytokine-induced survival, and genes promoting survival and up-regulated in cytokines were enriched at T1D risk loci. Using SNP-SELEX, we identified 2,229 variants in cytokine-responsive cCREs altering transcription factor (TF) binding, and variants altering binding of TFs regulating stress, inflammation, and apoptosis were enriched for T1D risk. At the 16p13 locus, a fine-mapped T1D variant altering TF binding in a cytokine-induced cCRE interacted with SOCS1, which promoted survival in cytokine exposure. Our findings reveal processes and genes acting in beta cells during inflammation that modulate T1D risk.Peer reviewe

The Tissue Kallikrein Family of Serine Proteases: Functional Roles in Human Disease and Potential as Clinical Biomarkers

Prostate specific antigen (PSA) or human kallikrein 3 (hK3) has long been an effective biomarker for prostate cancer. Now, other members of the tissue kallikrein (KLK) gene family are fast becoming of clinical interest due to their potential as prognostic biomarkers, particularly for hormone dependent cancers. The tissue kallikreins are serine proteases that are encoded by highly conserved multi-gene family clusters in rodents and humans. The rat and mouse loci contain 10 and 25 functional genes, respectively, while the human locus at 19q 13.4 contains 15 genes. The structural organization and size of these genes are similar across species; all genes have 5 coding exons that encode a prepro-enzyme. Although the physiological activators of these zymogens have not been described, in vitro biochemical studies show that some kallikreins can auto-activate and others can activate each other, suggesting that the kallikreins may participate in an enzymatic cascade similar to that of the coagulation cascade. These genes are expressed, to varying degrees, in a wide range of tissues suggesting a functional involvement in a diverse range of physiological and pathophysiological processes. These include roles in normal skin desquamation and psoriatic lesions, tooth development, neural plasticity, and Alzheimer's disease (AD). Of particular interest is the expression of many kallikreins in prostate, ovarian, and breast cancers where they are emerging as useful prognostic indicators of disease progression