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Papers by juan carlos casar

Matrix biology, May 1, 2024

Neuromuscular Disorders, Oct 1, 2010

Clinical Neurophysiology, Sep 1, 2008

Clinical Autonomic Research, Oct 16, 2023

Neurophysiologie Clinique-clinical Neurophysiology, Jan 28, 2023

Journal of Sleep Research

American Journal of Hypertension, 2021

International Journal of Molecular Sciences

Loss of motoneuron innervation (denervation) is a hallmark of neurodegeneration and aging of the ... more Loss of motoneuron innervation (denervation) is a hallmark of neurodegeneration and aging of the skeletal muscle. Denervation induces fibrosis, a response attributed to the activation and expansion of resident fibro/adipogenic progenitors (FAPs), i.e., multipotent stromal cells with myofibroblast potential. Using in vivo and in silico approaches, we revealed FAPs as a novel cell population that activates the transcriptional coregulators YAP/TAZ in response to skeletal muscle denervation. Here, we found that denervation induces the expression and transcriptional activity of YAP/TAZ in whole muscle lysates. Using the PdgfraH2B:EGFP/+ transgenic reporter mice to trace FAPs, we demonstrated that denervation leads to increased YAP expression that accumulates within FAPs nuclei. Consistently, re-analysis of published single-nucleus RNA sequencing (snRNA-seq) data indicates that FAPs from denervated muscles have a higher YAP/TAZ signature level than control FAPs. Thus, our work provides th...

Matrix Biology

Several common chronic diseases, muscular dystrophies (MDs), and aging lead to progressive fibrou... more Several common chronic diseases, muscular dystrophies (MDs), and aging lead to progressive fibrous connective tissue (fibrosis) accumulation in skeletal muscle. Cumulative past evidence points to the role of signaling lipids such as lysophosphatidic acid (LPA) and its receptors (LPARs) in different models of fibrosis. However, the potential contribution of these molecules to the fibrotic process in skeletal muscle has not been explored. Here, we show the expression of ATX/LPA/LPARs axis components in skeletal muscle, which suggests their potential relevance for the biology of this tissue. We investigated if the skeletal muscle responds to the stimulus of intramuscular (IM) LPA injections, finding an early induction of the pro-fibrotic factor connective tissue growth factor/Cellular Communication Network factor 2 (CCN2) and extracellular matrix (ECM) proteins. Also, we found that LPA induces an increase in the number of fibro/adipogenic progenitors (FAPs), which are the primary cellular source of myofibroblasts. These effects were for the most part prevented by the inhibitor Ki16425, which inhibits the LPA receptors LPA1 and LPA3, as well as in the LPA1-KO mice. We also evaluated the in vivo activation of extracellular signal-regulated kinases (ERK 1/2), AKT, c-Jun N-terminal kinase (JNK), and YAP in response to LPA. Our results show that LPA induces ERK 1/2 phosphorylation in WT muscle, but not in LPA1-KO mice. Treatment with the ERK 1/2 inhibitor U0126 partially prevented the induction of fibronectin in response to LPA, suggesting that this pathway is involved in LPA-induced fibrosis. Altogether, these results demonstrate that ATX/LPA/LPARs constitute a pro-fibrotic axis and suggest a possible role in muscular diseases.

License, which permits unrestricted use, distribution, and reproduction in any medium, provided t... more License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Stem cell therapy is a promising approach to cure degen-erative diseases, cancer, damaged tissues, or any disease for which there are very limited therapeutic options. Stem cell therapies could potentially improve the efficiency of the human body regenerative response following an injury or insult, in addition to being a source of powerful therapeutic compounds that hold the promise of the restoration of normal function of a given tissue. The abilities to identify, isolate, expand, and differentiate stem cells have been past barriers for developing therapies in patients and treatments using stem cells have long been viewed as potential or under development.The discovery of induced pluripotent stem cells (iPSC) has encouraged many researchers in the field of stem

American Journal of Hypertension

Maintenance of upright blood pressure critically depends on the autonomic nervous system and its ... more Maintenance of upright blood pressure critically depends on the autonomic nervous system and its failure leads to neurogenic orthostatic hypotension (NOH). The most severe cases are seen in neurodegenerative disorders caused by abnormal α-synuclein deposits: multiple system atrophy (MSA), Parkinson’s disease, Lewy body dementia, and pure autonomic failure (PAF). The development of novel treatments for NOH derives from research in these disorders. We provide a brief review of their underlying pathophysiology relevant to understand the rationale behind treatment options for NOH. The goal of treatment is not to normalize blood pressure but rather to improve quality of life and prevent syncope and falls by reducing symptoms of cerebral hypoperfusion. Patients not able to recognize NOH symptoms are at a higher risk for falls. The first step in the management of NOH is to educate patients on how to avoid high-risk situations and providers to identify medications that trigger or worsen NOH...

Journal of Cell Science, May 15, 2002

Stem cells international, 2015

Journal of cell science, Jan 15, 2002

Heparan sulfate chains of proteoglycans bind to and regulate the function of a wide variety of li... more Heparan sulfate chains of proteoglycans bind to and regulate the function of a wide variety of ligands. In myoblasts, heparan sulfate proteoglycans modulate basic fibroblast growth factor activity and regulate skeletal muscle differentiation. The aim of this study was to identify endogenous extracellular ligands for muscle cell heparan sulfate proteoglycans. [(35)S]heparin ligand blot assays identified a 33/30 kDa doublet (p33/30) in detergent/high ionic strength extracts and heparin soluble fractions obtained from intact C(2)C(12) myoblasts. p33/30 is localized on the plasma membrane or in the extracellular matrix where its level increases during muscle differentiation. Heparin-agarose-purified p33/30 was identified as histone H1. In vitro binding assays showed that histone H1 binds specifically to perlecan. Immunofluorescence microscopy showed that an extracellular pool of histone H1 colocalizes with perlecan in the extracellular matrix of myotube cultures and in regenerating skel...

Skeletal muscle, 2014

Duchenne muscular dystrophy (DMD) is characterized by the absence of the cytoskeletal protein dys... more Duchenne muscular dystrophy (DMD) is characterized by the absence of the cytoskeletal protein dystrophin, muscle wasting, increased transforming growth factor type beta (TGF-β) signaling, and fibrosis. At the present time, the only clinically validated treatments for DMD are glucocorticoids. These drugs prolong muscle strength and ambulation of patients for a short term only and have severe adverse effects. Andrographolide, a bicyclic diterpenoid lactone, has traditionally been used for the treatment of colds, fever, laryngitis, and other infections with no or minimal side effects. We determined whether andrographolide treatment of mdx mice, an animal model for DMD, affects muscle damage, physiology, fibrosis, and efficiency of cell therapy. mdx mice were treated with andrographolide for three months and skeletal muscle histology, creatine kinase activity, and permeability of muscle fibers were evaluated. Fibrosis and TGF-β signaling were evaluated by indirect immunofluorescence and...

Stem Cells and Development, 2012

Journal of Clinical Investigation, 2014