Biology subjects

Beuve, A.

Publications and source records attributed to Beuve, A..

3 recordsLinked to original sources

bioRxiv2024

Soluble guanylyl cyclase, the NO-receptor, regulates endothelium-dependent vascular relaxation via its transnitrosation activity.

We previously demonstrated that the NO-receptor soluble guanylyl cyclase (GC1) has the ability to transnitrosate other proteins in a reaction that involves, in some cases, oxidized Thioredoxin 1 (oTrx1). This transnitrosation cascade was established in vitro and we identified by mass spectrometry and mutational analysis Cys 610 (C610) of GC1 -subunit as a major donor of S-nitrosothiols (SNO). To assay the relevance of GC1 transnitrosation under physiological conditions and in oxidative pathologies, we studied a knock-in mouse in which C610 was replaced with a serine (KI C610S) under basal or angiotensin II (Ang II)-treated conditions. Despite similar GC1 expression and NO-stimulated cGMP-forming activity, the Ang II-treated KI mice displayed exacerbated oxidative pathologies including higher mean arterial pressure and more severe cardiac dysfunctions compared to the Ang II-treated WT. These phenotypes were associated with a drastic decrease in global S-nitrosation and in levels of SNO-Trx1 and SNO-RhoA in the KI mice. To investigate the mechanism underlying the dysregulation of blood pressure despite an intact NO-cGMP axis, pressure myography and in vivo intravital microscopy were conducted to analyze the vascular resistance tone. Both approaches indicated that, even in the absence of oxidative stress, the single mutation C610S led to a significant deficiency in acetylcholine-induced vasorelaxation while smooth muscle relaxation in response to NO remained unchanged. These findings indicate that the C610S mutation uncoupled the two NO signaling pathways involved in the endothelium and smooth muscle vasorelaxation and suggest that GC1-dependent S-nitrosation is a key player in endothelium-derived hyperpolarization.

biochemistry↗

bioRxiv2024

Endothelial TRPV4/Cx43 Signaling Complex Regulates Vasomotor Tone in Resistance Arteries

S-nitrosylation of Cx43 gap junction channels critically regulates communication between smooth muscle cells and endothelial cells. This posttranslational modification also induces the opening of undocked Cx43 hemichannels. However, its specific impact on vasomotor regulation remains unclear. Considering the role of endothelial TRPV4 channel activation in promoting vasodilation through nitric oxide (NO) production, we investigated the direct modulation of endothelial Cx43 hemichannels by TRPV4 channel activation. Using the proximity ligation assay, we identify that Cx43 and TRPV4 are found in close proximity in the endothelium of resistance arteries. In primary endothelial cell cultures from resistance arteries (ECs), GSK-induced TRPV4 activation enhances eNOS activity, increases NO production, and opens Cx43 hemichannels via direct S-nitrosylation. Notably, the elevated intracellular Ca2+ levels caused by TRPV4 activation were reduced by blocking Cx43 hemichannels. In ex vivo mesenteric arteries, inhibiting Cx43 hemichannels reduced endothelial hyperpolarization without affecting NO production in ECs, underscoring a critical role of TRPV4/Cx43 signaling in endothelial electrical behavior. We perturbed the proximity of Cx43/TRPV4 by disrupting lipid rafts in ECs using {beta}-cyclodextrin. Under these conditions, hemichannel activity, Ca2+ influx, and endothelial hyperpolarization were blunted upon GSK stimulation. Intravital microscopy of mesenteric arterioles in vivo further demonstrated that inhibiting Cx43 hemichannels activity, NO production and disrupting endothelial integrity reduce TRPV4-induced relaxation. These findings underscore a new pivotal role of Cx43 hemichannel associated with TRPV4 signaling pathway in modulating endothelial electrical behavior and vasomotor tone regulation.

physiology↗

bioRxiv2023

The soluble guanylyl cyclase pathway is inhibited to evade androgen deprivation-induced senescence and enable progression to castration resistance

Castration-resistant prostate cancer (CRPC) is fatal and therapeutically under-served. We describe a novel CRPC-restraining role for the vasodilatory soluble guanylyl cyclase (sGC) pathway. We discovered that sGC subunits are dysregulated during CRPC progression and its catalytic product, cyclic GMP (cGMP), is lowered in CRPC patients. Abrogating sGC heterodimer formation in castration-sensitive prostate cancer (CSPC) cells inhibited androgen deprivation (AD)-induced senescence, and promoted castration-resistant tumor growth. We found sGC is oxidatively inactivated in CRPC. Paradoxically, AD restored sGC activity in CRPC cells through redox-protective responses evoked to protect against AD-induced oxidative stress. sGC stimulation via its FDA-approved agonist, riociguat, inhibited castration-resistant growth, and the anti-tumor response correlated with elevated cGMP, indicating on-target sGC activity. Consistent with known sGC function, riociguat improved tumor oxygenation, decreasing the PC stem cell marker, CD44, and enhancing radiation-induced tumor suppression. Our studies thus provide the first evidence for therapeutically targeting sGC via riociguat to treat CRPC. Statement of significanceProstate cancer is the second highest cancer-related cause of death for American men. Once patients progress to castration-resistant prostate cancer, the incurable and fatal stage, there are few viable treatment options available. Here we identify and characterize a new and clinically actionable target, the soluble guanylyl cyclase complex, in castration-resistant prostate cancer. Notably we find that repurposing the FDA-approved and safely tolerated sGC agonist, riociguat, decreases castration-resistant tumor growth and re-sensitizes these tumors to radiation therapy. Thus our study provides both new biology regarding the origins of castration resistance as well as a new and viable treatment option.

cancer biology↗