Biology subjects

Desilets, A.

Publications and source records attributed to Desilets, A..

4 recordsLinked to original sources

bioRxiv2026

TMPRSS6 Cleavage of β-Klotho Modulates FGF19 Signaling

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent liver disorder worldwide, yet therapeutic options remain limited. TMPRSS6, a liver serine protease best known for its role in iron homeostasis, has recently emerged as a potential therapeutic target for MASLD. However, the molecular mechanisms linking TMPRSS6 to hepatic lipid metabolism remain incompletely understood. To identify novel TMPRSS6 substrates, we performed extracellular proteomic analyses of TMPRSS6-overexpressing cells. Among the proteins identified, {beta}-klotho (KLB), a co-receptor required for FGF19 and FGF21 signaling, emerged as a compelling candidate substrate. We demonstrate that TMPRSS6 interacts with KLB and promotes its proteolytic shedding in a catalytic activity-dependent manner. Functionally, TMPRSS6 reduced full-length KLB abundance at the cell surface and attenuated FGF19-dependent FGFR4 signaling in a heterologous expression system. Together, these findings identify KLB as a novel functional substrate of TMPRSS6, providing a mechanistic framework through which this protease may influence hepatic lipid metabolism. These results provide a rationale for investigating the regulation of KLB and other candidate substrates by TMPRSS6 in physiological models and further support its evaluation as a therapeutic target for MASLD.

biochemistry↗

bioRxiv2025

Isoform-Dependent Loss- and Gain-of-Function of the Gαs K53N Variant in Human Disease

The K53N mutation in Gs has been identified in patients with Albrights Hereditary Osteodystrophy (AHO), pseudohypoparathyroidism type 1A (PHP1a), and dilated cardiomyopathy; however, its molecular mechanism remains unclear. Here, we characterize the molecular, cellular, and physiological consequences of the K53N mutation in both long and short isoform of Gs. Biochemical analyses reveal that K53N disrupts nucleotide exchange and GTP hydrolysis, rendering both the short (Gs-S) and long (Gs-L) isoforms unresponsive to activation by G protein-coupled receptors (GPCRs) or cholera toxin. Both isoforms display a loss-of-function phenotype, failing to trigger cAMP production in response to {beta}2-adrenergic, parathyroid hormone, or vasopressin receptor stimulation. Notably, only the long isoform (Gs-L K53N) displays constitutive, receptor-independent cAMP generation. The mutation also reduces protein stability, weakens G{beta}{gamma} subunit interaction, and reduces plasma membrane localization. In neonatal rat ventricular cardiomyocytes, K53N impairs cAMP signaling and exerts dominant-negative effects on isoproterenol-induced responses. Strikingly, only Gs-L K53N abolishes isoproterenol-stimulated calcium release, directly implicating this isoform in the pathogenesis of cardiomyopathy. Collectively, these findings identify K53N as a unique Gs mutation that confers both loss- and gain-of-function properties in an isoform-specific manner, providing mechanistic insight into its complex pathogenicity in endocrine and cardiac tissues.

pharmacology and toxicology↗

bioRxiv2024

Development of ketobenzothiazole-based peptidomimetic TMPRSS13 inhibitors with low nanomolar potency

TMPRSS13, a member of the Type II Transmembrane Serine Proteases (TTSP) family, is involved in cancer progression and in cell entry of respiratory viruses. To date, no inhibitors have been specifically developed toward this protease. In this study, a chemical library of 65 ketobenzothiazole-based peptidomimetic molecules was screened against a proteolytically active form of recombinant TMPRSS13 to identify novel inhibitors. Following an initial round of screening, subsequent synthesis of additional derivatives supported by molecular modelling, uncovered important molecular determinants involved in TMPRSS13 inhibition. One inhibitor, N-0430, achieved low nanomolar affinity towards TMPRSS13 activity in a cellular context. Using a SARS-CoV-2 pseudovirus cell entry model, we further show the ability of N-0430 to block TMPRSS13-dependent entry of the pseudovirus. The identified peptidomimetic inhibitors and the molecular insights of their potency gained from this study will aid in the development of specific TMPRSS13 inhibitors.

pharmacology and toxicology↗

bioRxiv2021

A novel highly potent inhibitor of TMPRSS2-like proteases blocks SARS-CoV-2 variants of concern and is broadly protective against infection and mortality in mice

The COVID-19 pandemic caused by the SARS-CoV-2 virus remains a global public health crisis. Although widespread vaccination campaigns are underway, their efficacy is reduced against emerging variants of concern (VOCs) 1,2. Development of host-directed therapeutics and prophylactics could limit such resistance and offer urgently needed protection against VOCs 3,4. Attractive pharmacological targets to impede viral entry include type-II transmembrane serine proteases (TTSPs), such as TMPRSS2, whose essential role in the virus lifecycle is responsible for the cleavage and priming of the viral spike protein 5-7. Here, we identify and characterize a small-molecule compound, N-0385, as the most potent inhibitor of TMPRSS2 reported to date. N-0385 exhibited low nanomolar potency and a selectivity index of >106 at inhibiting SARS-CoV-2 infection in human lung cells and in donor-derived colonoids 8. Importantly, N-0385 acted as a broad-spectrum coronavirus inhibitor of two SARS-CoV-2 VOCs, B.1.1.7 and B.1.351. Strikingly, single daily intranasal administration of N-0385 early in infection significantly improved weight loss and clinical outcomes, and yielded 100% survival in the severe K18-human ACE2 transgenic mouse model of SARS-CoV-2 disease. This demonstrates that TTSP-mediated proteolytic maturation of spike is critical for SARS-CoV-2 infection in vivo and suggests that N-0385 provides a novel effective early treatment option against COVID-19 and emerging SARS-CoV-2 VOCs.

microbiology↗