Biology subjects

Thorrez, L.

Publications and source records attributed to Thorrez, L..

3 recordsLinked to original sources

bioRxiv2023

Similar metabolic pathways are affected in both Congenital Myasthenic Syndrome 22 and Prader Willi Syndrome

Loss of prolyl endopeptidase-like (PREPL) encoding a serine hydrolase with (thio)esterase activity leads to the recessive metabolic disorder Congenital Myasthenic Syndrome-22 (CMS22). It is characterized by severe neonatal hypotonia, feeding problems, growth retardation, and hyperphagia leading to rapid weight gain later in childhood. The phenotypic similarities with Prader-Willi syndrome (PWS) are striking, suggesting that similar pathways are affected. The aim of this study was to identify changes in the hypothalamic-pituitary axis in mouse models for both disorders and to examine mitochondrial function in skin fibroblasts of patients and knockout cell lines. We have demonstrated that Prepl is downregulated in the brains of neonatal PWS-IC-p/+m mice. In addition, the hypothalamic-pituitary axis is similarly affected in both Prepl-/- and PWS-IC-p/+m mice resulting in defective orexigenic signaling and growth retardation. Furthermore, we demonstrated that mitochondrial function is altered in PREPL knockout HEK293T cells and can be rescued with the supplementation of coenzyme Q10. Finally, PREPL-deficient and PWS patient skin fibroblasts display defective mitochondrial bioenergetics. The mitochondrial dysfunction in PWS fibroblasts can be rescued by overexpression of PREPL. In conclusion, we provide the first molecular links between CMS22 and PWS, raising the possibility that PREPL substrates might become therapeutic targets for treating both disorders. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/566752v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@308afforg.highwire.dtl.DTLVardef@f5a8feorg.highwire.dtl.DTLVardef@29d9eforg.highwire.dtl.DTLVardef@1a3061a_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

The Urtica Dioica Agglutinin Prevents Rabies Virus Infection in a Muscle Explant Model

Infection with the rabies virus (RABV) results, once symptoms develop, in a 100% lethal neurological disease. Post-exposure prophylaxis (PEP), consists of a combination of vaccination and anti-rabies immunoglobulins (RIGs); it is 100% effective if administered early after infection. Because of the limited availability, alternatives for RIGs are needed. To that end we evaluated a panel of 33 different lectins for their effect on RABV infection in cell culture. Several lectins, with either mannose or GlcNAc specificity elicited anti-RABV activity of which the GlcNAc specific Urtica dioica Agglutinin (UDA) was selected for further studies. UDA was found to prevent entry of the virus into the host cell. To further assess the potential of UDA, a physiologically relevant RABV infection muscle explant model was developed. Strips of dissected swine skeletal muscle that were kept in culture medium could be productively infected with the RABV. When the infection of the muscle strips was carried out in the presence of UDA, RABV replication was completely prevented. We thus developed a physiologically relevant RABV muscle infection model. UDA (i) may serve as a reference for further studies and (ii) holds promise as a cheap and simple to produce alternative for RIGs in PEP.

pathology↗

bioRxiv2020

Furin controls β cell function via mTORC1 signaling

Furin is a proprotein convertase (PC) responsible for proteolytic activation of a wide array of precursor proteins within the secretory pathway. It maps to the PRC1 locus, a type 2 diabetes susceptibility locus, yet its specific role in pancreatic {beta} cells is largely unknown. The aim of this study was to determine the role of furin in glucose homeostasis. We show that furin is highly expressed in human islets, while PCs that potentially could provide redundancy are expressed at considerably lower levels. {beta} cell-specific furin knockout ({beta}furKO) mice are glucose intolerant, due to smaller islets with lower insulin content and abnormal dense core secretory granule morphology. RNA expression analysis and differential proteomics on {beta}furKO islets revealed activation of Activating Transcription Factor 4 (ATF4), which was mediated by mammalian target of rapamycin C1 (mTORC1). {beta}furKO cells show impaired cleavage of the essential V-ATPase subunit Ac45, and by blocking this pump in {beta} cells the mTORC1 pathway is activated. Furthermore, {beta}furKO cells show lack of insulin receptor cleavage and impaired response to insulin. Taken together, these results suggest a model of mTORC1-ATF4 hyperactivation in {beta} cells lacking furin, which causes {beta} cell dysfunction.

physiology↗