title: Contribution of p62 to Phenotype Transition of Coronary Arterial Myocytes with Defective Autophagy.
abstract: BACKGROUND
  Autophagy disorder contributes to dedifferentiation of arterial smooth muscle cells, but the mechanisms are poorly understood. Here, we sought to investigate the role of scaffolding adaptor p62/SQSTM1 (p62) in phenotype switching of mouse coronary arterial myocytes (CAMs) induced by CD38 gene deficiency or lysosomal dysfunction which blocks autophagic flux in the cells.
  
  
  METHODS
  Protein expression was measured by western blot analysis and immunofluorescent staining. Cell cycle and proliferation rate were analyzed by flow cytometry and MTS assay respectively. mRNA abundance was tested by qRT-PCR.
  
  
  RESULTS
  CD38 gene deficiency or bafilomycin A1 (baf), a selective lysosomal inhibitor treatment increased proliferation rate and vimentin expression in CAMs which was prevented by p62 gene silencing. Cell percentage in G<Sub>2</Sub>/M and G<Sub>0</Sub>/G<Sub>1</Sub> phase was decreased and increased by CD38 deficiency or baf treatment, respectively which was accompanied by accrual of cyclin-dependent kinase 1 (CDK1) protein. Although free ubiquitin content was increased, the colocalization of it to CDK1 was markedly decreased in CD38-/- or baf treated CAMs. Furthermore, the changes in both cell cycle and CDK1 ubiquitinylation could be restored by p62 gene silencing.
  
  
  CONCLUSIONS
  The results suggest in CD38-/- or baf treated CAMs, p62 accumulation promotes phenotype transition and proliferation by accelerating cell cycle progress through G<Sub>2</Sub>/M which might relate to the compromised ubiquitinylation and degradation of CDK1.
authors.forename: Junxiang
authors.initials: J
authors.lastname: Bao
authors.forename: Guangbi
authors.initials: G
authors.lastname: Li
authors.forename: Xinxu
authors.initials: X
authors.lastname: Yuan
authors.forename: Pin-Lan
authors.initials: PL
authors.lastname: Li
authors.forename: Erich
authors.initials: E
authors.lastname: Gulbins
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000172:deficiency / Q000235:genetics; D000818:Animals; D001343:Autophagy / Q000187:drug effects; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology; D003331:Coronary Vessels / Q000166:cytology; D008247:Lysosomes / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D010641:Phenotype; D034741:RNA, Small Interfering / Q000378:metabolism; D000071456:Sequestosome-1 Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects; D014746:Vimentin / Q000235:genetics / Q000378:metabolism
chemical_list: D018942:Macrolides; D034741:RNA, Small Interfering; D000071456:Sequestosome-1 Protein; C101343:Sqstm1 protein, mouse; D014746:Vimentin; D002738:Chloroquine; C040929:bafilomycin A1; D016203:CDC2 Protein Kinase; D051997:ADP-ribosyl Cyclase 1
keywords: Arteriosclerosis; Autophagy; CD38; Differentiation; Vascular smooth muscle cell