Biology subjects

Quesada, I.

Publications and source records attributed to Quesada, I..

4 recordsLinked to original sources

bioRxiv2025

Increased TGFβ /Activin-Smad2 signaling is associated with pancreatic β-cell dysfunction and glucose intolerance in gestational diabetes mellitus

BackgroundGestational diabetes mellitus (GDM) is the most common metabolic disease during pregnancy and increases the prevalence of type 2 diabetes in both mothers and offspring. GDM management provides a window of opportunity to prevent and lower the global burden of diabetes across life. Molecular mechanisms underlying GDM are poorly defined. In this study, we explore the potential involvement of transforming growth factor beta (TGF-{beta}) signaling in GDM as this pathway has been reported to affect pancreatic {beta}-cell development, proliferation and identity. MethodsWe developed a GDM animal model. Serum circulating levels of TGF{beta} family ligands were measured in mice and human GDM. Pancreatic TGF{beta} signaling was investigated at the level of gene and protein expression. ResultsOur GDM animal model recapitulates the main pathophysiological features of human GDM including glucose intolerance, decreased insulin sensitivity and pancreatic {beta}-cell malfunction. Islets from GDM mice showed impaired insulin secretion and content, altered ion channel activity, and decreased {beta}-cell replication rate. This was accompanied by increased Smad2 signaling activation. Elevated serum activin-A and inhibin levels were found in mice and human GDM, suggesting their role as upstream signaling transducers of pancreatic Smad2 activation. Pharmacological inhibition of TGF{beta}/Activin-Smad2 signaling in mouse pancreatic islets resulted in improved pancreatic {beta}-cell function and regeneration capacity of {beta}-cells. ConclusionsOur data disclose that disruption of pancreatic Smad2 pathway plays a critical role in the pathogenesis of GDM, contributing to abnormal glucose homeostasis and inadequate insulin secretion. Attenuation of this signaling pathway could represent a putative therapeutic target for GDM. HighlightsO_LIHigh fat diet just before and during pregnancy leads to gestational diabetes in mice. C_LIO_LIActivin and inhibin serum levels are increased in human and mice gestational diabetes. C_LIO_LIEnhanced pancreatic Smad2 signaling contributes to inadequate insulin secretion in gestational diabetes. C_LIO_LIInhibition of Smad2 signaling improves pancreatic {beta}-cell function and proliferation. C_LI

physiology↗

bioRxiv2023

Rescue of blood coagulation Factor VIII exon-16 mis-splicing by antisense oligonucleotides

The human Factor VIII (F8) protein is essential for the blood coagulation cascade and specific F8 mutations cause the rare bleeding disorder Hemophilia A (HA). Here, we investigated the impact of HA-causing single-nucleotide mutations on F8 pre-mRNA splicing. We found that 14/97 ([~]14.4%) coding sequence mutations tested in our study induced exon skipping. Splicing patterns of 4/11 ([~]36.4%) F8 exons tested were especially sensitive to the presence of common disease-causing mutations. RNA-chemical probing analyses revealed a three-way junction structure at the 3' end of intron 15 (TWJ-3-15). TWJ-3-15 sequesters the polypyrimidine tract, a key determinant of 3' splice site strength. Using exon-16 of the F8 gene as a model, we designed specific antisense oligonucleotides (ASOs) that target TWJ-3-15 and identified three that promote the splicing of F8 exon-16. Interaction of TWJ-3-15 with ASOs increases accessibility of the polypyrimidine tract and inhibits the binding of hnRNPA1-dependent splicing silencing factors. Moreover, ASOs targeting TWJ-3-15 rescue diverse splicing-sensitive HA-causing mutations, most of which are distal to the 3 splice site being impacted. The TWJ-3-15 structure and its effect on mRNA splicing provide a model for HA etiology in patients harboring specific F8 mutations and provide a framework for precision RNA-based HA therapies.

molecular biology↗

bioRxiv2022

EXPLORING THE EFFECTS OF METABOLISM-DISRUPTING CHEMICALS ON PANCREATIC alpha-CELL BIOLOGY: A SCREENING TESTING APPROACH

Humans are constantly exposed to many environmental pollutants, some of which have been largely acknowledged as key factors in the development of metabolic disorders such as diabetes and obesity. These chemicals have been classified as endocrine-disrupting chemicals (EDCs) and, more recently, since they can interfere with metabolic functions, they have been renamed as metabolism-disrupting chemicals (MDCs). MDCs are present in many consumer products, including food packaging, personal care products, plastic bottles and containers, and detergents. The scientific literature has ever-increasingly focused on insulin-releasing pancreatic {beta}-cells as one of the main targets for MDCs. Evidence highlights that these substances may disrupt glucose homeostasis, altering pancreatic {beta}-cell physiology. However, their potential impact on glucagon-secreting pancreatic -cells remains poorly known despite the essential role that this cellular type plays in controlling glucose metabolism. In the present study, we have selected seven paradigmatic EDCs representing major toxic classes, including bisphenols, phthalates, perfluorinated compounds, metals, and pesticides. By using an in vitro cell-based model, the pancreatic -cell line TC1-9, we have explored the effects of these compounds on pancreatic -cell viability, gene expression, and secretion. Our results indicated that most of the selected chemicals studied caused functional alterations in pancreatic -cells. Moreover, we revealed, for the first time, their direct effects on key molecular aspects of pancreatic -cell biology.

pharmacology and toxicology↗

bioRxiv2020

Bisphenol-S and Bisphenol-F alter mouse pancreatic β-cell ion channel expression and activity and insulin release through an estrogen receptor ERβ mediated pathway

Bisphenol-S (BPS) and Bisphenol-F (BPF) are current Bisphenol-A (BPA) substitutes. Here we used pancreatic {beta}-cells from wild type (WT) and estrogen receptor {beta} (ER{beta}) knockout (BERKO) mice to investigate the effects of BPS and BPF on insulin secretion, and the expression and activity of ion channels involved in {beta}-cell function. BPS or BPF rapidly increased insulin release and diminished ATP-sensitive K+ (KATP) channel activity. Similarly, 48 h treatment with BPS or BPF enhanced insulin release and decreased the expression of several ion channel subunits in {beta}-cells from WT mice, yet no effects were observed in cells from BERKO mice. PaPE-1, a ligand designed to preferentially trigger extranuclear-initiated ER pathways, mimicked the effects of bisphenols, suggesting the involvement of extranuclear-initiated ER{beta} pathways. Molecular dynamics simulations indicated differences in ER{beta} ligand-binding domain dimer stabilization and solvation free energy among different bisphenols and PaPE-1. Our data suggest a mode of action involving ER{beta} whose activation alters three key cellular events in {beta}-cell, namely ion channel expression and activity, and insulin release. These results may help to improve the hazard identification of bisphenols.

pharmacology and toxicology↗