RESUMO
Clonal hematopoiesis of indeterminate potential (CHIP) arises from aging-associated acquired mutations in hematopoietic progenitors, which display clonal expansion and produce phenotypically altered leukocytes. We associated CHIP-DNMT3A mutations with a higher prevalence of periodontitis and gingival inflammation among 4,946 community-dwelling adults. To model DNMT3A-driven CHIP, we used mice with the heterozygous loss-of-function mutation R878H, equivalent to the human hotspot mutation R882H. Partial transplantation with Dnmt3aR878H/+ bone marrow (BM) cells resulted in clonal expansion of mutant cells into both myeloid and lymphoid lineages and an elevated abundance of osteoclast precursors in the BM and osteoclastogenic macrophages in the periphery. DNMT3A-driven clonal hematopoiesis in recipient mice promoted naturally occurring periodontitis and aggravated experimentally induced periodontitis and arthritis, associated with enhanced osteoclastogenesis, IL-17-dependent inflammation and neutrophil responses, and impaired regulatory T cell immunosuppressive activity. DNMT3A-driven clonal hematopoiesis and, subsequently, periodontitis were suppressed by rapamycin treatment. DNMT3A-driven CHIP represents a treatable state of maladaptive hematopoiesis promoting inflammatory bone loss.
Assuntos
Hematopoiese Clonal , DNA (Citosina-5-)-Metiltransferases , DNA Metiltransferase 3A , Periodontite , Animais , DNA (Citosina-5-)-Metiltransferases/metabolismo , DNA (Citosina-5-)-Metiltransferases/genética , Camundongos , Hematopoiese Clonal/genética , Humanos , Periodontite/genética , Periodontite/patologia , Mutação , Masculino , Feminino , Inflamação/genética , Inflamação/patologia , Osteoclastos/metabolismo , Camundongos Endogâmicos C57BL , Adulto , Interleucina-17/metabolismo , Interleucina-17/genética , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Hematopoese/genética , Osteogênese/genética , Células-Tronco Hematopoéticas/metabolismo , Reabsorção Óssea/genética , Reabsorção Óssea/patologia , Pessoa de Meia-IdadeRESUMO
We identify biomarkers for disease progression in three type 2 diabetes cohorts encompassing 2,973 individuals across three molecular classes, metabolites, lipids and proteins. Homocitrulline, isoleucine and 2-aminoadipic acid, eight triacylglycerol species, and lowered sphingomyelin 42:2;2 levels are predictive of faster progression towards insulin requirement. Of ~1,300 proteins examined in two cohorts, levels of GDF15/MIC-1, IL-18Ra, CRELD1, NogoR, FAS, and ENPP7 are associated with faster progression, whilst SMAC/DIABLO, SPOCK1 and HEMK2 predict lower progression rates. In an external replication, proteins and lipids are associated with diabetes incidence and prevalence. NogoR/RTN4R injection improved glucose tolerance in high fat-fed male mice but impaired it in male db/db mice. High NogoR levels led to islet cell apoptosis, and IL-18R antagonised inflammatory IL-18 signalling towards nuclear factor kappa-B in vitro. This comprehensive, multi-disciplinary approach thus identifies biomarkers with potential prognostic utility, provides evidence for possible disease mechanisms, and identifies potential therapeutic avenues to slow diabetes progression.
Assuntos
Diabetes Mellitus Tipo 2 , Ilhotas Pancreáticas , Camundongos , Animais , Masculino , Diabetes Mellitus Tipo 2/metabolismo , Glicemia/metabolismo , Ilhotas Pancreáticas/metabolismo , Insulina/metabolismo , Lipídeos , Biomarcadores/metabolismo , Moléculas de Adesão Celular/metabolismo , Proteínas da Matriz Extracelular/metabolismoRESUMO
OBJECTIVES: To find plasma biomarkers prognostic of type 2 diabetes, which could also inform on pancreatic ß-cell deregulations or defects in the function of insulin target tissues. METHODS: We conducted a systems biology approach to characterize the plasma lipidomes of C57Bl/6J, DBA/2J, and BALB/cJ mice under different nutritional conditions, as well as their pancreatic islet and liver transcriptomes. We searched for correlations between plasma lipids and tissue gene expression modules. RESULTS: We identified strong correlation between plasma triacylglycerols (TAGs) and islet gene modules that comprise key regulators of glucose- and lipid-regulated insulin secretion and of the insulin signaling pathway, the two top hits were Gck and Abhd6 for negative and positive correlations, respectively. Correlations were also found between sphingomyelins and islet gene modules that overlapped in part with the gene modules correlated with TAGs. In the liver, the gene module most strongly correlated with plasma TAGs was enriched in mRNAs encoding fatty acid and carnitine transporters as well as multiple enzymes of the ß-oxidation pathway. In humans, plasma TAGs also correlated with the expression of several of the same key regulators of insulin secretion and the insulin signaling pathway identified in mice. This cross-species comparative analysis further led to the identification of PITPNC1 as a candidate regulator of glucose-stimulated insulin secretion. CONCLUSION: TAGs emerge as biomarkers of a liver-to-ß-cell axis that links hepatic ß-oxidation to ß-cell functional mass and insulin secretion.
Assuntos
Células Secretoras de Insulina/metabolismo , Triglicerídeos/metabolismo , Animais , Biomarcadores/sangue , Biomarcadores/metabolismo , Células Cultivadas , Glucose/metabolismo , Humanos , Secreção de Insulina , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Triglicerídeos/sangueRESUMO
Metabolic diseases are associated with an increased risk of severe COVID-19 and conversely, new-onset hyperglycemia and complications of preexisting diabetes have been observed in COVID-19 patients. Here, we performed a comprehensive analysis of pancreatic autopsy tissue from COVID-19 patients using immunofluorescence, immunohistochemistry, RNA scope and electron microscopy and detected SARS-CoV-2 viral infiltration of beta-cells in all patients. Using SARS-CoV-2 pseudoviruses, we confirmed that isolated human islet cells are permissive to infection. In eleven COVID-19 patients, we examined the expression of ACE2, TMPRSS and other receptors and factors, such as DPP4, HMBG1 and NRP1, that might facilitate virus entry. Whereas 70% of the COVID-19 patients expressed ACE2 in the vasculature, only 30% displayed ACE2-expression in beta-cells. Even in the absence of manifest new-onset diabetes, necroptotic cell death, immune cell infiltration and SARS-CoV-2 viral infection of pancreatic beta-cells may contribute to varying degrees of metabolic dysregulation in patients with COVID-19.
Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/patologia , Células Secretoras de Insulina/virologia , Receptores de Coronavírus/metabolismo , SARS-CoV-2/isolamento & purificação , Serina Endopeptidases/metabolismo , Adulto , Idoso , Autopsia , Complicações do Diabetes/patologia , Complicações do Diabetes/virologia , Diabetes Mellitus/patologia , Dipeptidil Peptidase 4/metabolismo , Feminino , Proteínas HMGN/metabolismo , Humanos , Células Secretoras de Insulina/metabolismo , Masculino , Pessoa de Meia-Idade , Neuropilina-1/metabolismo , Especificidade de Órgãos/fisiologiaRESUMO
Most research on human pancreatic islets is conducted on samples obtained from normoglycaemic or diseased brain-dead donors and thus cannot accurately describe the molecular changes of pancreatic islet beta cells as they progress towards a state of deficient insulin secretion in type 2 diabetes (T2D). Here, we conduct a comprehensive multi-omics analysis of pancreatic islets obtained from metabolically profiled pancreatectomized living human donors stratified along the glycemic continuum, from normoglycemia to T2D. We find that islet pools isolated from surgical samples by laser-capture microdissection display remarkably more heterogeneous transcriptomic and proteomic profiles in patients with diabetes than in non-diabetic controls. The differential regulation of islet gene expression is already observed in prediabetic individuals with impaired glucose tolerance. Our findings demonstrate a progressive, but disharmonic, remodelling of mature beta cells, challenging current hypotheses of linear trajectories toward precursor or transdifferentiation stages in T2D. Furthermore, through integration of islet transcriptomics with preoperative blood plasma lipidomics, we define the relative importance of gene coexpression modules and lipids that are positively or negatively associated with HbA1c levels, pointing to potential prognostic markers.
Assuntos
Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Biomarcadores , Glicemia , Suscetibilidade a Doenças , Metabolismo Energético , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Insulina/metabolismo , Doadores Vivos , Metabolômica , ProteômicaRESUMO
BACKGROUND: The availability of human pancreatic islets with characteristics closely resembling those present in vivo is instrumental for ex vivo studies in diabetes research. SCOPE OF REVIEW: In this review we propose metabolically phenotyped surgical patients as a novel source of pancreatic tissue for islet research. Laser Capture Microdissection from snap frozen surgical specimens is a relatively simple, reproducible and scalable method to isolate islets of highest purity for many types of "omics" analyses. Fresh pancreatic tissue slices enable the functional characterization of living islet cells in situ through dynamic experiments. Access to complete medical history and laboratory values for each donor offers the opportunity of direct correlations with different "omics" data and detailed metabolic profiling prior to pancreas surgery. Peripheral blood samples complete the picture of each patient and represent a platform for pursuit of biomarkers with uniquely comprehensive background information in regard to the donor's islet cells. MAJOR CONCLUSIONS: Living donors provide the scientific community with a steady and abundant supply of excellent material to study islets closest to their in situ environment, thus advancing our understanding of their physiology in health and diseases.