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Small-Vessel Vasculopathy Due to Aberrant Autophagy in LAMP-2 Deficiency.


ABSTRACT: Lysosomal associated membrane protein 2 (LAMP2) is physiologically implicated in autophagy. A genetic LAMP2 defect causes Danon disease, which consists of two major phenotypes of myopathy and cardiomyopathy. In addition, arteriopathy may manifest on rare occasions but the pathological basis remains unknown. We encountered two Danon families that developed small-vessel vasculopathy in the coronary or cerebral arteries. To investigate the underlying mechanisms, we characterized the biological features of LAMP-2-deficient mice and cultured cells. LAMP-2-deficient mice at 9-24 months of age showed medial thickening with luminal stenosis due to proliferation of vascular smooth muscle cells (VSMC) in muscular arteries. Ultrastructural analysis of VSMC revealed various autophagic vacuoles scattered throughout the cytoplasm, suggesting impaired autophagy of long-lived metabolites and degraded organelles (i.e., mitochondria). The VSMC in Lamp2 null mice expressed more vimentin but less ?-smooth muscle actin (?-SMA), indicating a switch from contractile to synthetic phenotype. Silencing of LAMP2 in cultured human brain VSMC showed the same phenotypic transition with mitochondrial fragmentation, enhanced mitochondrial respiration, and overproduction of reactive oxygen species (ROS). These findings indicate that LAMP-2 deficiency leads to arterial medial hypertrophy with the phenotypic conversion of VSMC, resulting from age-dependent accumulation of cellular waste generated by aberrant autophagy.

SUBMITTER: Nguyen HT 

PROVIDER: S-EPMC5820257 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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Small-Vessel Vasculopathy Due to Aberrant Autophagy in LAMP-2 Deficiency.

Nguyen Huan T HT   Noguchi Satoru S   Sugie Kazuma K   Matsuo Yoshiyuki Y   Nguyen Chuyen T H CTH   Koito Hitoshi H   Shiojima Ichiro I   Nishino Ichizo I   Tsukaguchi Hiroyasu H  

Scientific reports 20180220 1


Lysosomal associated membrane protein 2 (LAMP2) is physiologically implicated in autophagy. A genetic LAMP2 defect causes Danon disease, which consists of two major phenotypes of myopathy and cardiomyopathy. In addition, arteriopathy may manifest on rare occasions but the pathological basis remains unknown. We encountered two Danon families that developed small-vessel vasculopathy in the coronary or cerebral arteries. To investigate the underlying mechanisms, we characterized the biological feat  ...[more]

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