title: Kallikrein 6 is a novel molecular trigger of reactive astrogliosis.
abstract: Kallikrein-related peptidase 6 (KLK6) is a trypsin-like serine protease upregulated at sites of central nervous system (CNS) injury, including de novo expression by reactive astrocytes, yet its physiological actions are largely undefined. Taken with recent evidence that KLK6 activates G-protein-coupled protease-activated receptors (PARs), we hypothesized that injury-induced elevations in KLK6 contribute to the development of astrogliosis and that this occurs in a PAR-dependent fashion. Using primary murine astrocytes and the Neu7 astrocyte cell line, we show that KLK6 causes astrocytes to transform from an epitheliod to a stellate morphology and to secrete interleukin 6 (IL-6). By contrast, KLK6 reduced expression of glial fibrillary acidic protein (GFAP). The stellation-promoting activities of KLK6 were shown to be dependent on activation of the thrombin receptor, PAR1, as a PAR1-specific inhibitor, SCH79797, blocked KLK6-induced morphological changes. The ability of KLK6 to promote astrocyte stellation was also shown to be linked to activation of protein kinase C (PKC). These studies indicate that KLK6 is positioned to serve as a molecular trigger of select physiological processes involved in the development of astrogliosis and that this is likely to occur at least in part by activation of the G-protein-coupled receptor, PAR1.
authors.affiliation: Neurobiology of Disease Program, Mayo Medical and Graduate School, Rochester, MN 55905, USA. Scarisbrick.Isobel@mayo.edu
authors.forename: Isobel A
authors.initials: IA
authors.lastname: Scarisbrick
authors.forename: Maja
authors.initials: M
authors.lastname: Radulovic
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Burda
authors.forename: Nadya
authors.initials: N
authors.lastname: Larson
authors.forename: Sachiko I
authors.initials: SI
authors.lastname: Blaber
authors.forename: Caterina
authors.initials: C
authors.lastname: Giannini
authors.forename: Michael
authors.initials: M
authors.lastname: Blaber
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Vandell
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000378:metabolism; D049109:Cell Proliferation; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D006984:Hypertrophy; D015850:Interleukin-6 / Q000378:metabolism; D007610:Kallikreins / Q000378:metabolism*; D051379:Mice; D011493:Protein Kinase C / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism; D013116:Spinal Cord / Q000201:enzymology / Q000378:metabolism / Q000473:pathology
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D015850:Interleukin-6; C556015:PARPBP protein, human; D044463:Receptor, PAR-1; D011493:Protein Kinase C; C103551:KLK6 protein, human; D007610:Kallikreins