Biology subjects

Aiello, E.

Publications and source records attributed to Aiello, E..

4 recordsLinked to original sources

bioRxiv2025

Small non-coding RNA profiling reveals inflammatory and mitochondrial related changes in aging β-cells and islet macrophages

Aging is accompanied by functional decline and increased senescence of pancreatic {beta}-cells. These changes may be influenced by islet-resident macrophages (iMACs) that remodel tissue in response to environmental cues. To explore the molecular mechanisms underlying {beta}-cell aging and senescence, we profiled small non-coding RNAs (sncRNAs) in FACS-sorted {beta}-cells and iMACs from 3-, 12-, and 22-month-old mouse islets or from senescence-associated {beta}gal (SA-{beta}gal) positive {beta}-cells of 8-month-old mice. Overall, senescent {beta}-cells displayed distinct sncRNA signatures that only partially overlapped with those of aging. However, several miRNAs previously found to be deregulated in obese or diabetic conditions were modulated in both aging and senescent {beta}-cells, including upregulation of miRNAs linked to inflammation. In vitro exposure to pro-inflammatory cytokines partially reproduced these profiles. Aging also reshaped the {beta}-cell tRNA-derived fragment (tRF) pool, enhancing global mitochondrial tRF levels. Interestingly, some changes in miRNAs and tRFs were {beta}-cell specific, whereas others occurred also in other aged metabolic tissues. iMACs also showed age-related sncRNA remodeling, including upregulation of anti-inflammatory miRNAs and mitochondrial tRFs, suggesting adaptive immune reprogramming. Together, these data reveal a profound, coordinated reshaping of the sncRNA landscape in {beta}-cells and iMACs during aging, offering new insights into molecular mechanisms driving age-related islet dysfunction.

molecular biology↗

bioRxiv2025

5'tRNA-derived fragments modulate β-cell homeostasis and islet macrophage activation in type 2 diabetes

During obesity and type 2 diabetes, pancreatic {beta}-cells face chronic environmental stress, while islet-resident macrophages (iMACs) undergo metabolic reprogramming that exacerbates {beta}-cell dysfunction. Stress-induced cleavage of transfer RNAs (tRNAs) generates tRNA-derived fragments (tRFs), whose role in this context is not fully understood. We identify elevated levels of 5tRFGlu(CTC) and 5tRFGly(GCC) in {beta}-cells and iMACs from db/db mice and in islets from type 2 diabetic patients. Notably, 5tRFGlu(CTC) is also induced under prediabetic conditions and inversely correlates with insulin secretion. Lipotoxic stress triggers their production via Angiogenin-mediated cleavage. Blocking 5tRFGlu(CTC) in islets protects against {beta}-cell apoptosis and restores insulin secretion under palmitate stress. Using a {beta}-cell/macrophage co-culture system, we show that {beta}-cell contact shapes a unique macrophage phenotype (iMAC-like) that shifts upon palmitate exposure--recapitulating in vivo observations. Inhibiting 5tRFGlu(CTC) in iMAC-like cells prevents this activation switch, reduces {beta}-cell stress, and improves insulin secretion. Mechanistically, 5tRFGlu(CTC) interacts with RNA-binding proteins to regulate transcriptional and post-transcriptional pathways linked to immune activation, extracellular matrex remodeling, neurogenesis, and oxidative stress. Our study identifies 5tRFs as key mediators of islet microenvironment remodeling in diabetes, offering new insights into intercellular stress signaling in metabolic disease.

cell biology↗

bioRxiv2023

Comprehensive IsomiR sequencing profile of human pancreatic islets and EndoC-βH1 beta-cells

Aims/HypothesisMiRNAs play a crucial role in regulating the islet transcriptome, influencing beta cell functions and pathways. Emerging evidence suggests that during biogenesis a single miRNA locus can generate various sequences, known as isomiRNAs (isomiRs). However, a comprehensive profiling analysis of isomiRs in human pancreatic islets and beta cells is still lacking. This study aims to unveil the isomiRs expression profile in Laser Capture Microdissected (LCM) human pancreatic islets (HI) from non-diabetic donors and in the human beta cell line EndoC-{beta}H1, in order to shed light on novel molecular mechanisms governing beta cell function. MethodsRNA was extracted from LCM HI deriving from n=19 non-diabetic donors and from EndoC-{beta}H1 beta cells. Small RNA-seq was performed. Data were processed with the sRNAbench online pipeline for miRNAs/isomiRs quantification. Results were further validated using an external miRNA-seq database (isomiRdb). ResultsIn both HI and EndoC-{beta}H1, isomiRs accounted for a substantial proportion of total miRNA reads (HI: 59.4+/-1.9%; EndoC-{beta}H1: 43.8+/-0.6%). Among isomiRs, the most prevalent types were 3-end modifications, including trimming (HI=71.8+/-2.8%; EndoC-{beta}H1=55.8+/-1.0%) and extension (HI: 12.1+/-1.9%; EndoC-{beta}H1: 17.4+/-0.9%), followed by non-templated addition (HI: 9.8+/-0.9%; EndoC-{beta}H1: 14.0+/-1.2%). The analysis of the composition of the n=10 most expressed miRNAs highlighted a significant contribution of reads assigned to isomiRs. For instance, the most abundant miRNA, miR-375-3p, resulted from 59.7+/-2.4% of canonical and 40.3+/-2.4% of isomiRs in EndoC-{beta}H1 and from 45.3+/-2.0% of canonical and 54.7+/-2.0% of isomiR reads in HI. Interestingly, miR-7-5p, a beta cell-specific miRNA, was predominantly expressed as an isomiR both in EndoC-{beta}H1 (65.3+/-2.7%) and in HI (82.4+/-1.4%). To identify a reliable beta cell isomiR signature, common sequences detected in HI and EndoC-{beta}H1 were filtered based on their contribution to total miRNA expression, ultimately resulting in a set of 46 isomiRs. The expression of the isomiR signature in beta cells was further evaluated using an external database, isomiRdb, which contains small-RNA sequencing data from 99 different human cell types. This analysis revealed a significant enrichment of 11 out of the 46 isomiRs in beta cells compared to other cell types. The signature was functionally characterized through regression analysis with clinical and metabolic parameters related to beta cell function in non-diabetic individuals, demonstrating a significant negative correlation between basal insulin secretion and isomiR-411-5p, but not with its corresponding canonical miRNA. Conclusion/InterpretationThis study provides a comprehensive profile of isomiR expression in pancreatic islets and beta cells, highlighting the potential significance of isomiRs as novel regulators of beta cell function. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/566223v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@145f36borg.highwire.dtl.DTLVardef@1701433org.highwire.dtl.DTLVardef@13e5866org.highwire.dtl.DTLVardef@1dbe50_HPS_FORMAT_FIGEXP M_FIG C_FIG Research in ContextO_ST_ABSWhat is already know about this subject?C_ST_ABS- isomiRs are sequence variants of microRNAs (miRNAs) and may have distinct functional role respect to the canonical sequence. - isomiRs show cell/tissue specificity and are involved in multiple disease contexts. What is the key question?- What is the profile of isomiRs in human pancreatic islets (HI) and in beta cells? - Do isomiRs have a functional role in beta cells? What are the new findings?- IsomiRs represent a relevant fraction of total miRNAs in HI and beta cells. - 3end miRNA sequence modifications are the major fraction of isomiRs in beta cells. - A set of n=11 isomiRs, more expressed than their canonical miRNAs, are enriched in beta cells compared to the other human cell types. - Specific isomiRs are associated with beta cell glucose sensitivity and basal insulin secretion. How might this impact on clinical practice in the foreseeable future?- A comprehensive profile of isomiRs in beta cells may improve our understanding of molecular mechanisms driving beta cell function and dysfunction. - A highly detailed and granular view of miRNAs sequence variants and their expression levels may help in the design of novel therapeutic RNA-based strategies.

molecular biology↗

bioRxiv2021

Increased expression of viral sensor MDA5 in pancreatic islets and in hormone-negative endocrine cells in recent onset type 1 diabetic donors

The interaction between genetic and environmental factors determines the development of type 1 diabetes (T1D). Some viruses are capable of infecting and damaging pancreatic {beta}-cells, whose antiviral response could be modulated by specific viral RNA receptors and sensors such as Melanoma Differentiation Associated gene 5 (MDA5), encoded by the IFIH1 gene. MDA5 has been shown to be involved in pro-inflammatory and immunoregulatory outcomes, thus determining the response of pancreatic islets to viral infections. Although the function of MDA5 has been previously well explored, a detailed immunohistochemical characterization of MDA5 in pancreatic tissues of non-diabetic and T1D donors is still missing. In the present study we used multiplex immunofluorescence imaging analysis to characterize MDA5 expression and distribution in pancreatic tissues obtained from 22 organ donors (10 non-diabetic autoantibody-negative, 2 autoantibody-positive, 8 recent-onset and 2 long-standing T1D). In non-diabetic control donors, MDA5 was expressed both in - and in {beta}-cells. The colocalization rate imaging analysis showed that MDA5 was preferentially expressed in -cells. In T1D donors, we observed an increased colocalization rate MDA5-glucagon respect to MDA5-insulin in comparison to non-diabetic controls; such increase was more pronounced in recent onset respect to long standing T1D donors. Of note, an increased colocalization rate MDA5-glucagon was found in insulin-deficient-islets (IDI) respect to insulin containing islets (ICI). Strikingly, in T1D donors we detected the presence of MDA5-positive/hormones-negative endocrine islet-like clusters, putatively deriving from dedifferentiation or neogenesis phoenomena. These clusters were exclusively identified in recent onset donors and not detected in autoantibody-positive non-diabetic or T1D long-standing ones. In conclusion, we showed that MDA5 is preferentially expressed in -cells and its expression is increased in recent onset T1D donors. Finally, we observed that MDA5 may also characterize the phenotype of dedifferentiated or newly forming islet cells, thus opening to novel roles for MDA5 in pancreatic endocrine cells.

immunology↗