Schoeniger, E. | Search bioRxiv

bioRxiv2022

Identification of a unique transcriptomic signature associated with islet amyloidosis

AimsThis cross-sectional study aims to identify potential transcriptomic changes conveyed by presence of amyloid deposits in islets from pancreatic tissue obtained from metabolically profiled living donors. MethodsAfter establishing Thioflavin S as the most sensitive approach to detect islet amyloid plaques, we utilized RNA sequencing data obtained from laser capture microdissected islets to define transcriptomic effects of this pathological entity. The RNA sequencing data was used to identify differentially expressed genes by linear modeling. Further analyses included functional enrichment analysis of KEGG and Hallmark gene sets as well as a weighted gene correlation network analysis. ResultsEleven differentially expressed genes were identified in islets affected by amyloidosis. Enrichment analyses pointed to signatures related to protein aggregation diseases, energy metabolism and inflammatory response. A gene co-expression module was identified that correlated to islet amyloidosis. ConclusionAlthough the influence of underlying Type 2 diabetes could not be entirely excluded, this study presents a valuable insight into the biology of islet amyloidosis, particularly providing hints into the potential relationship between islet amyloid deposition and structural and functional proteins involved in insulin secretion. Research in contextO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LIIslet amyloidosis is the only histological marker of Type 2 diabetes in the pancreas C_LIO_LIIndividuals not suffering from Type 2 diabetes can also be affected by islet amyloidosis C_LIO_LIThe clinicopathological significance of this phenomenon is still unclear C_LI What is the key question?O_LIDoes the islet transcriptome of individuals with islet amyloidosis provide explanations for the onset of this phenomenon and its pathophysiological value? C_LI What are the new findings?O_LIIslet transcriptomes of affected subjects exhibit only limited transcriptomic differences compared to unaffected ones. C_LIO_LIStructural and functional proteins involved in insulin secretion machinery may be involved in the pathophysiological sequence of amyloid formation C_LI

systems biology↗

bioRxiv2020

Multi-omics profiling of living human pancreatic islet donors reveals heterogeneous beta cell trajectories toward type 2 diabetes

Existing studies do not sufficiently describe the molecular changes of pancreatic islet beta cells leading to their deficient insulin secretion in type 2 diabetes (T2D). Here we address this deficiency with a comprehensive multi-omics analysis of metabolically profiled pancreatectomized living human donors stratified along the glycemic continuum from normoglycemia to T2D. Islet pools isolated from surgical samples by laser-capture microdissection had remarkably heterogeneous transcriptomic and proteomic profiles in diabetics, but not in non-diabetic controls. Transcriptomics analysis of this unique cohort revealed islet genes already dysregulated in prediabetic individuals with impaired glucose tolerance. Our findings demonstrate a progressive but disharmonic remodeling of mature beta cells, challenging current hypotheses of linear trajectories toward precursor or trans-differentiation stages in T2D. Further, integration of islet transcriptomics and pre-operative blood plasma lipidomics data enabled us to define the relative importance of gene co-expression modules and lipids positively or negatively associated with HbA1c levels, pointing to potential prognostic markers.

bioinformatics↗