TY - JOUR
T1 - Multimerin-2 maintains vascular stability and permeability
AU - Pellicani, Rosanna
AU - Poletto, Evelina
AU - Andreuzzi, Eva
AU - Paulitti, Alice
AU - Doliana, Roberto
AU - Bizzotto, Dario
AU - Braghetta, Paola
AU - Colladel, Roberta
AU - Tarticchio, Giulia
AU - Sabatelli, Patrizia
AU - Bucciotti, Francesco
AU - Bressan, Giorgio
AU - Iozzo, Renato V.
AU - Colombatti, Alfonso
AU - Bonaldo, Paolo
AU - Mongiat, Maurizio
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Multimerin-2 is an extracellular matrix glycoprotein and member of the elastin microfibril interface-located (EMILIN) family of proteins. Multimerin-2 is deposited along blood vessels and we previously demonstrated that it regulates the VEGFA/VEGFR2 signaling axis and angiogenesis. However, its role in modulating vascular homeostasis remains largely unexplored. Here we identified Multimerin-2 as a key molecule required to maintain vascular stability. RNAi knockdown of Multimerin-2 in endothelial cells led to cell-cell junctional instability and increased permeability. Mechanistically cell-cell junction dismantlement occurred through the phosphorylation of VEGFR2 at Tyr951, activation of Src and phosphorylation of VE-cadherin. To provide an in vivo validation for these in vitro effects, we generated Multimerin-2−/− (Mmrn2−/−) mice. Although Mmrn2−/− mice developed normally and displayed no gross abnormalities, endothelial cells displayed cell junctional defects associated with increased levels of VEGFR2 phospho-Tyr949 (the murine counterpart of human Tyr951), impaired pericyte recruitment and increased vascular leakage. Of note, tumor associated vessels were defective in Mmrn2−/− mice, with increased number of small and often collapsed vessels, concurrent with a significant depletion of pericytic coverage. Consequently, the Mmrn2−/− vessels were less perfused and leakier, leading to increased tumor hypoxia. Chemotherapy efficacy was markedly impaired in Mmrn2−/− mice and this was associated with poor drug delivery to the tumor xenografts. Collectively, our findings demonstrate that Multimerin-2 is required for proper vessel homeostasis and stabilization, and unveil the possibility to utilize expression levels of this glycoprotein in predicting chemotherapy efficacy.
AB - Multimerin-2 is an extracellular matrix glycoprotein and member of the elastin microfibril interface-located (EMILIN) family of proteins. Multimerin-2 is deposited along blood vessels and we previously demonstrated that it regulates the VEGFA/VEGFR2 signaling axis and angiogenesis. However, its role in modulating vascular homeostasis remains largely unexplored. Here we identified Multimerin-2 as a key molecule required to maintain vascular stability. RNAi knockdown of Multimerin-2 in endothelial cells led to cell-cell junctional instability and increased permeability. Mechanistically cell-cell junction dismantlement occurred through the phosphorylation of VEGFR2 at Tyr951, activation of Src and phosphorylation of VE-cadherin. To provide an in vivo validation for these in vitro effects, we generated Multimerin-2−/− (Mmrn2−/−) mice. Although Mmrn2−/− mice developed normally and displayed no gross abnormalities, endothelial cells displayed cell junctional defects associated with increased levels of VEGFR2 phospho-Tyr949 (the murine counterpart of human Tyr951), impaired pericyte recruitment and increased vascular leakage. Of note, tumor associated vessels were defective in Mmrn2−/− mice, with increased number of small and often collapsed vessels, concurrent with a significant depletion of pericytic coverage. Consequently, the Mmrn2−/− vessels were less perfused and leakier, leading to increased tumor hypoxia. Chemotherapy efficacy was markedly impaired in Mmrn2−/− mice and this was associated with poor drug delivery to the tumor xenografts. Collectively, our findings demonstrate that Multimerin-2 is required for proper vessel homeostasis and stabilization, and unveil the possibility to utilize expression levels of this glycoprotein in predicting chemotherapy efficacy.
KW - angiogenesis
KW - extracellular matrix
KW - tumor growth
KW - tumor microenvironment
KW - vascular homeostasis
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U2 - 10.1016/j.matbio.2019.08.002
DO - 10.1016/j.matbio.2019.08.002
M3 - Article
AN - SCOPUS:85071138746
JO - Matrix Biology
JF - Matrix Biology
SN - 0945-053X
ER -