Biology subjects

Robidel, E.

Publications and source records attributed to Robidel, E..

2 recordsLinked to original sources

bioRxiv2026

Cell-specific isolation and functional analysis of primary cardiomyocyte-derived large extracellular vesicles from infarcted mouse hearts

Extracellular vesicles (EVs) are membrane-bound particles secreted by all cells and serve as critical mediators of intercellular communication in both physiological and pathological contexts. However, elucidating the precise functions of endogenous EVs remains challenged by a fundamental technical bottleneck: current isolation methodologies depend on shared physical properties or generic surface markers, preventing the selective enrichment of cell-type-specific EVs within complex tissues. Consequently, EVs recovered from biofluids or tissue extracts represent heterogeneous populations, confounding the direct attribution of biochemical signatures and biological activities to distinct cellular origins. Here, we describe a versatile genetic-labeling and affinity-based purification strategy that enables the selective isolation of cell-specific primary EV. Using cardiomyocyte-derived EV (CM-EVs) as a proof-of-concept, we crossed Myh6-Cre mice with the ROSA26-mTmG reporter line to restrict membrane-targeted GFP expression to cardiomyocytes. Following myocardial infarction, cardiac EV were recovered and GFP-positive CM-EVs were selectively purified by anti-GFP nanobody-based magnetic pulldown. This approach yields highly enriched, functional cardiomyocyte-derived extracellular vesicles (CM-EVs). To accommodate diverse analytical needs, we established two distinct elution workflows: (i) a denaturing protocol optimized for downstream proteomics and immunoblotting, and (ii) a gentle, non-denaturing protocol that preserves vesicle integrity and biological activity for downstream in vitro and in vivo functional assays. Using this method, we characterized CM-EVs size distribution and proteomic signature, and demonstrated their capacity to transfer functional cargo to target cells in vitro. Because the purification approach relies solely on targeting a genetically restricted membrane tag rather than assumed surface markers, it is immediately adaptable to virtually any cell type for which a validated Cre driver exists. This method removes a long-standing bottleneck in EV research and provides a broadly applicable platform for deciphering the biochemical composition and in-vivo functions of cell-type-specific primary EV in physiological and pathological settings.

cell biology↗

bioRxiv2025

Blood-borne sphingosine 1-phosphate maintains vascular resistance and cardiac function.

G protein-coupled receptors (GPCRs) are key regulators of cardiovascular function that provide targets for the treatment of cardiovascular disease. Sphingosine 1-phosphate (S1P) is an erythrocyte- and platelet-derived lipid mediator with cognate GPCRs on endothelial cells (EC), vascular smooth muscle cells (VSMC) and cardiomyocytes. S1P circulates in plasma bound to apolipoprotein M (ApoM)-containing high-density lipoproteins (HDL) and to albumin. Circulating S1P levels correlate positively with systolic blood pressure in hypertension and negatively with severity in septic shock and with left ventricular (LV) function in coronary heart disease. In mice, impaired S1P binding to HDL or signaling to EC both trigger hypertension, supporting an essential role for HDL-S1P in supporting endothelial function. The roles of albumin-S1P and myocyte S1PRs in cardiovascular homeostasis remain incompletely defined. Contrasting isolated HDL-S1P deficiency, we report that non-selective depletion of circulating S1P pools in mice impairs LV contractile function and induces hypotension and resistance to the spontaneous increase in blood pressure with age. Cardiac output was preserved in naive S1P deficient mice by compensatory LV dilation, but cardiac reserve reduced in a dobutamine stress test. These phenotypes tracked with hematopoietic cell S1P production and were partially or fully reversed by erythrocyte transfusion. Hypotension was accompanied by reduced peripheral resistance, and S1P infusion dose-dependently increased vascular resistance in isolated perfused kidneys from wild-type mice but not mice with compound deficiency in S1PR2&3. Epistatic analysis supported a critical role for S1PR3 in S1P-dependent blood pressure regulation and pointed to a distinct origin of the cardiac phenotype. Although circulating S1P is elevated in hypertensive mice and humans, increasing circulating S1P was not sufficient to induce hypertension in naive mice. These observations suggests that albumin-S1P crosses the endothelium in resistance arteries to gain access to contractile VSMC S1P receptors, and that myocyte S1PR signaling is essential for vascular resistance and blood pressure maintenance in mice. They also highlight the role for plasma chaperones in specifying vascular responses to S1P and the relevance of S1P as a biomarker and potential therapeutic target for blood pressure regulation and heart failure.

physiology↗