title: Defective autophagy is a key feature of cerebral cavernous malformations.
abstract: Cerebral cavernous malformation (CCM) is a major cerebrovascular disease affecting approximately 0.3-0.5% of the population and is characterized by enlarged and leaky capillaries that predispose to seizures, focal neurological deficits, and fatal intracerebral hemorrhages. Cerebral cavernous malformation is a genetic disease that may arise sporadically or be inherited as an autosomal dominant condition with incomplete penetrance and variable expressivity. Causative loss-of-function mutations have been identified in three genes, KRIT1 (CCM1), CCM2 (MGC4607), and PDCD10 (CCM3), which occur in both sporadic and familial forms. Autophagy is a bulk degradation process that maintains intracellular homeostasis and that plays essential quality control functions within the cell. Indeed, several studies have identified the association between dysregulated autophagy and different human diseases. Here, we show that the ablation of the KRIT1 gene strongly suppresses autophagy, leading to the aberrant accumulation of the autophagy adaptor p62/SQSTM1, defective quality control systems, and increased intracellular stress. KRIT1 loss-of-function activates the mTOR-ULK1 pathway, which is a master regulator of autophagy, and treatment with mTOR inhibitors rescues some of the mole-cular and cellular phenotypes associated with CCM. Insufficient autophagy is also evident in CCM2-silenced human endothelial cells and in both cells and tissues from an endothelial-specific CCM3-knockout mouse model, as well as in human CCM lesions. Furthermore, defective autophagy is highly correlated to endothelial-to-mesenchymal transition, a crucial event that contributes to CCM progression. Taken together, our data point to a key role for defective autophagy in CCM disease pathogenesis, thus providing a novel framework for the development of new pharmacological strategies to prevent or reverse adverse clinical outcomes of CCM lesions.
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Saverio
authors.initials: S
authors.lastname: Marchi
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Corricelli
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Eliana
authors.initials: E
authors.lastname: Trapani
authors.affiliation: IFOM FIRC Institute of Molecular Oncology, Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bravi
authors.affiliation: Department of Medical Sciences, University of Torino, Torino, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pittaro
authors.affiliation: Department of Biotechnological and Applied Clinical Science, University of L'Aquila, L'Aquila, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Delle Monache
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Letizia
authors.initials: L
authors.lastname: Ferroni
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Patergnani
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Sonia
authors.initials: S
authors.lastname: Missiroli
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Goitre
authors.affiliation: Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena, Italy.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Trabalzini
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rimessi
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Giorgi
authors.affiliation: Department of Biomedical Sciences, University of Padova, Padova, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Zavan
authors.affiliation: Department of Medical Sciences, University of Torino, Torino, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Cassoni
authors.affiliation: IFOM FIRC Institute of Molecular Oncology, Milano, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Dejana
authors.affiliation: Department of Clinical and Biological Sciences, University of Torino, Torino, Italy francesco.retta@unito.it paolo.pinton@unife.it.
authors.forename: Saverio Francesco
authors.initials: SF
authors.lastname: Retta
authors.affiliation: Department of Morphology, Surgery and Experimental Medicine, Section of Pathology Oncology and Experimental Biology, University of Ferrara, Ferrara, Italy francesco.retta@unito.it paolo.pinton@unife.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pinton
mesh_terms: D000818:Animals; D001343:Autophagy; D002478:Cells, Cultured; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000502:physiology; D055785:Gene Knockdown Techniques; D020786:Hemangioma, Cavernous, Central Nervous System / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D000075927:KRIT1 Protein; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D000075927:KRIT1 Protein; C107928:KRIT1 protein, human; C491535:Krit1 protein, mouse; D008869:Microtubule-Associated Proteins; D011518:Proto-Oncogene Proteins
keywords: CCM; ROS; autophagy; endothelial‐to‐mesenchymal transition (EndMt); mTOR