title: Phenotypic transition of corpus cavernosum smooth muscle cells subjected to hypoxia.
abstract: Corpora cavernosum smooth muscle cells (CCSMCs) have been shown to play a critical role in the male erectile response and are involved in the pathogenesis of multiple causes of erectile dysfunction (ED). To investigate the underlying mechanisms, we studied the changes that CCSMCs undergo under hypoxic conditions in vitro. The identified and characterized CCSMCs were exposed to hypoxia for 48 h and its phenotypic changes were examined by light and electron microscopy, MTS assay and flow cytometry. The mRNA and protein levels of TGF-β1 and type I/III collagen, as well as CCSMC phenotype marker proteins and their transcriptional factors, were assessed by qPCR, immunofluorescence analysis and western blotting. Our results showed that CCSMCs became hypertrophic with loss of myofilament bundles and formation of an extensive rough endoplasmic reticulum (RER) under hypoxic conditions, with inhibited cell proliferation and enhanced cell apoptosis. This was accompanied by the increased synthesis of TGF-β1 and types I and III collagen. Moreover, smooth muscle cell phenotypic markers were also affected by hypoxic conditions, as indicated by the decrease in α-SMA, desmin and CNN1 expression and the increase in vimentin expression. These changes corresponded to changes in associated transcriptional factors, such as the increase in Elk-1 and KLF-4 expression and decrease in Myocd expression. In addition, a HIF-1α knockdown effectively reversed the hypoxia-induced CCSMC phenotype, whereas its overexpression induced the dedifferentiation phenotype. These results indicate that CCSMCs undergo a phenotypic transition under hypoxic conditions.
authors.affiliation: Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Bodong
authors.initials: B
authors.lastname: Lv
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhao
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Huang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Kebing
authors.initials: K
authors.lastname: Yang
authors.forename: Shanshan
authors.initials: S
authors.lastname: Liu
authors.forename: Chunlei
authors.initials: C
authors.lastname: Fan
authors.forename: Huiying
authors.initials: H
authors.lastname: Fu
authors.forename: Zhaodian
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015687:Cell Hypoxia; D002461:Cell Line, Transformed; D002469:Cell Separation; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000648:ultrastructure; D010413:Penis / Q000166:cytology*; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016326:Extracellular Matrix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D003094:Collagen