Biology subjects

Gonzalo, P.

Publications and source records attributed to Gonzalo, P..

3 recordsLinked to original sources

bioRxiv2021

The Endoplasmic Reticulum pool of Bcl-xL dampens the Unfolded Protein Response through IP3R-dependent Calcium Release

Apoptosis plays a role in cell homeostasis in both normal development and disease. Bcl-xL, a member of the Bcl-2 family of proteins, regulates the intrinsic mitochondrial pathway of apoptosis. It is overexpressed in several cancers. Bcl-xL has a dual subcellular localization and is found at the mitochondria as well as the endoplasmic reticulum (ER). However, the biological significance of its ER localization is unclear. In order to decipher the functional contributions of the mitochondrial and reticular pools of Bcl-xL, we generated genetically modified mice expressing exclusively Bcl-xL at the ER, referred to as ER-xL, or the mitochondria, referred to as Mt-xL. By performing cell death assays, we showed that ER-xL MEFs show increased vulnerability to apoptotic stimuli but are more resistant to ER stress. Furthermore, ER-xL MEFs demonstrated a reduced expression of the Unfolded Protein Response (UPR) markers upon ER stress and displayed reduced inositol trisphosphate receptor (IP3R)-mediated ER calcium release. Collectively, our data show that upon ER stress, Bcl-xL negatively regulates IP3R-mediated calcium flux from the ER, which prevents ER calcium depletion and maintains the UPR and subsequent cell death in check. This work reveals a moonlighting function of Bcl-xL at the ER, apart from its cliche regulation of apoptosis.

cell biology↗

bioRxiv2020

Macrophages promote endothelial-to-mesenchymal transition via MT1-MMP/TGFβ after myocardial infarction

Macrophages produce factors that participate in cardiac repair and remodeling after myocardial infarction (MI); however, how these factors crosstalk with other cell types mediating repair is not fully understood. In this study, we demonstrated that cardiac macrophages increased expression of Mmp14 (MT1-MMP) 7 days post-MI. Specific macrophage-targeting of MT1-MMP (MT1-MMP{Delta}LysM mice) attenuates post-MI cardiac dysfunction, reduces fibrosis, and preserves the cardiac capillary network. Mechanistically, we showed that MT1-MMP activates latent TGF{beta}1 in macrophages, leading to paracrine SMAD2-mediated signaling in endothelial cells and endothelial-to-mesenchymal transition (EndMT). Post-MI MT1-MMP{Delta}LysM hearts contained fewer cells undergoing EndMT than their wild-type counterparts, and MT1-MMP-deficient macrophages showed a reduced ability to induce EndMT in co-cultures with endothelial cells. Our results demonstrate the contribution of EndMT to cardiac fibrosis and adverse remodeling post-MI and identify macrophage MT1-MMP as a key regulator of this process. The identified mechanism has potential as a therapeutic target in ischemic heart disease.

immunology↗

bioRxiv2020

Isoprenylcysteine carboxylmethyltransferase basedtherapy for Hutchinson Gilford progeria syndrome

Progerin is a mutant prelamin A variant that causes Hutchinson-Gilford progeria syndrome (HGPS, progeria), a rare genetic disease characterized by premature aging and death in childhood. Although several therapeutic approaches have been explored in experimental models, clinical trials have shown very limited benefits in HGPS patients. Here, we describe the development of UCM-13207, a new potent inhibitor of isoprenylcysteine carboxylmethyltransferase (ICMT) that reduces progerin nuclear accumulation and ameliorates the typical alterations in progeroid human and mouse cells. UCM-13207 also improves phenotypic anomalies and extends lifespan in progerin-expressing LmnaG609G/G609G mice. These results support the potential use of UCM-13207 as a new treatment for progeria.

pharmacology and toxicology↗