title: Protein O-mannosylation is crucial for human mesencyhmal stem cells fate.
abstract: Human mesenchymal stem cells (MSC) are promising cell types in the field of regenerative medicine. Although many pathways have been dissected in the effort to better understand and characterize MSC potential, the impact of protein N- or O-glycosylation has been neglected. Deficient protein O-mannosylation is a pathomechanism underlying severe congenital muscular dystrophies (CMD) that start to develop at the embryonic developmental stage and progress in the adult, often in tissues where MSC exert their function. Here we show that O-mannosylation genes, many of which are putative or verified glycosyltransferases (GTs), are expressed in a similar pattern in MSC from adipose tissue, bone marrow, and umbilical cord blood and that their expression levels are retained constant during mesengenic differentiation. Inhibition of the first players of the enzymatic cascade, POMT1/2, resulted in complete abolishment of chondrogenesis and alterations of adipogenic and osteogenic potential together with a lethal effect during myogenic induction. Since to date, no therapy for CMD is available, we explored the possibility of using MSC extracellular vesicles (EVs) as molecular source of functional GTs mRNA. All MSC secrete POMT1 mRNA-containing EVs that are able to efficiently fuse with myoblasts which are among the most affected cells by CMD. Intriguingly, in a pomt1 patient myoblast line EVs were able to partially revert O-mannosylation deficiency and contribute to a morphology recovery. Altogether, these results emphasize the crucial role of protein O-mannosylation in stem cell fate and properties and open the possibility of using MSC vesicles as a novel therapeutic approach to CMD.
authors.affiliation: Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Ragni
authors.affiliation: Centre for Organismal Studies, Cell Chemistry and Center for Molecular Biology, University of Heidelberg, 69120, Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lommel
authors.affiliation: Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi" (INGM), Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Moro
authors.affiliation: Istituto Nazionale Genetica Molecolare "Romeo ed Enrica Invernizzi" (INGM), Milan, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Crosti
authors.affiliation: Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Lavazza
authors.affiliation: Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Parazzi
authors.affiliation: Division of Neuromuscular Diseases and Neuroimmunology, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Saredi
authors.affiliation: Centre for Organismal Studies, Cell Chemistry and Center for Molecular Biology, University of Heidelberg, 69120, Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Strahl
authors.affiliation: Cell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. lorenza.lazzari@policlinico.mi.it.
authors.forename: L
authors.initials: L
authors.lastname: Lazzari
mesh_terms: D002454:Cell Differentiation; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D006031:Glycosylation; D006801:Humans; D008364:Mannosyltransferases / Q000235:genetics / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D024510:Muscle Development; D009136:Muscular Dystrophies / Q000151:congenital* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D008364:Mannosyltransferases; C082696:protein O-mannosyltransferase
keywords: Congenital muscular dystrophy; Differentiation; Extracellular vesicles; Mesenchymal stem cells; O-Mannosylation; POMT1