title: KPC1 expression and essential role after acute spinal cord injury in adult rat.
abstract: KPC1 (Kip1 ubiquitylation-promoting complex 1) is the catalytic subunit of the ubiquitin ligase KPC, which regulates the degradation of the cyclin-dependent kinase inhibitor p27(kip1) at the G1 phase of the cell cycle. To elucidate the expression and role of KPC1 in nervous system lesion and repair, we performed an acute spinal cord contusion injury (SCI) model in adult rats. Western blot analysis showed a significant up-regulation of KPC1 and a concomitant down-regulation of p27(kip1) following spinal injury. Immunohistochemistry and immunofluorescence revealed wide expression of KPC1 in the spinal cord, including expression in neurons and astrocytes. After injury, KPC1 expression was increased predominantly in astrocytes, which highly expressed PCNA, a marker for proliferating cells. Co-immunoprecipitation demonstrated increased interactions between p27(kip1) and KPC1 4 days after injury. To understand whether KPC1 plays a role in astrocyte proliferation, we applied LPS to induce astrocyte proliferation in vitro. Western blot analysis demonstrated that p27(kip1) expression was negatively correlated with KPC1 expression following LPS stimulation. Immunofluorescence analysis showed subcellular localizations of p27(kip1) and KPC1 were also changed following the stimulation of astrocytes with LPS. These results suggest that KPC1 is related to the down-regulation of p27(kip1); this event may be involved in the proliferation of astrocytes after SCI.
authors.affiliation: Orthopedic Department, Affiliated Hospital of Nantong University, and The Jiangsu Province Key Laboratory of Neuroregeneration, Nantong University, 226001, Nantong, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.forename: Shuangwei
authors.initials: S
authors.lastname: Zhang
authors.forename: Xiujie
authors.initials: X
authors.lastname: Wu
authors.forename: Weipeng
authors.initials: W
authors.lastname: Huan
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Liu
authors.forename: Haixiang
authors.initials: H
authors.lastname: Wei
authors.forename: Aiguo
authors.initials: A
authors.lastname: Shen
authors.forename: Honglin
authors.initials: H
authors.lastname: Teng
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000502:physiology; D015415:Biomarkers / Q000378:metabolism; D049109:Cell Proliferation; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism*; D006801:Humans; D008297:Male; D021122:Protein Subunits / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D021122:Protein Subunits; C558223:Ubac1 protein, rat; D050760:Cyclin-Dependent Kinase Inhibitor p27; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases