Biology subjects

Martinez-Pinna, J.

Publications and source records attributed to Martinez-Pinna, J..

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

PROTON TRANSFER FROM LIGANDS ACTIVATES EXTRANUCLEAR-INITIATED ESTROGEN RECEPTOR SIGNALING

Withdrawal StatementThe authors have withdrawn this manuscript because they have identified errors in the western blots in Figures 1B, C, and G, as well as in Figure 2 A and B. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

biochemistry↗

bioRxiv2022

G protein-coupled oestrogen receptor activation by Bisphenol-A disrupts protection from apoptosis conferred by oestrogen receptors ERα and ERβ in pancreatic beta cells

17{beta}-estradiol protects pancreatic {beta}-cells from apoptosis via the estrogen receptors ER, ER{beta} and GPER. Conversely, the endocrine disruptor Bisphenol-A (BPA), which exerts multiple effects in this cell type via the same estrogen receptors, increased basal apoptosis. The molecular initiated events that trigger these opposite actions have yet to be identified. We demonstrated that combined genetic downregulation and pharmacological blockade of each estrogen receptor increased apoptosis to a different extent. The increase in apoptosis induced by BPA was diminished by the pharmacological blockade or the genetic silencing of GPER, and it was partially reproduced by the GPER agonist G1. BPA and G1-induced apoptosis were abolished upon pharmacological inhibition, silencing of ER and ER{beta}, or in dispersed islet cells from ER{beta} knockout (BERKO) mice. Yet, the ER and ER{beta} agonists, PPT and DPN, respectively, had no effect on beta cell viability. To exert their biological actions, ER and ER{beta} form homodimers and heterodimers. Molecular dynamic simulations together with proximity ligand assay and coimmunoprecipitation experiments indicated that the interaction of BPA with ER and ER{beta} as well as the GPER activation by G1 decreased ER{beta} heterodimers. We propose that ER{beta} heterodimers play an antiapoptotic role in beta cells and that BPA- and G1-induced decrease in ER{beta} heterodimers leads to beta cell apoptosis. Unveiling how different estrogenic chemicals affect the crosstalk among estrogen receptors should help to identify diabetogenic endocrine disruptors. HighlightsO_LIPharmacological blockade and gene silencing of estrogen receptors ER, ER{beta} and GPER indicate that they are antiapoptotic in basal conditions. C_LIO_LIGPER activation by G1 and BPA triggered apoptosis via a crosstalk with ER and ER{beta}. C_LIO_LIBPA interaction with ER and ER{beta} as well as GPER activation decreased ER{beta} heterodimers, which was associated to increased apoptosis. C_LIO_LIThis pathway represents a novel molecular initiating event underlying the pro-apoptotic effect of BPA C_LIO_LIThe EndoC-{beta}H1 cell line may be a valid model of human {beta}-cells for identifying diabetogenic pollutants. C_LI

physiology↗

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↗