METHODS: PNMA5 mutants were generated through deletion or site-directed mutagenesis and transiently expressed in human cancer cell lines to investigate their role in apoptosis, subcellular localization, and potential interaction with MOAP-1 through apoptosis assays, fluorescence microscopy, and co-immunoprecipitation studies, respectively.
RESULTS: Over-expressed human PNMA5 exhibited nuclear localization pattern in both MCF-7 and HeLa cells. Deletion mapping and mutagenesis studies showed that C-terminus of PNMA5 is responsible for nuclear localization, while the amino acid residues (391KRRR) within the C-terminus of PNMA5 are required for nuclear targeting. Deletion mapping and co-immunoprecipitation studies showed that PNMA5 interacts with MOAP-1 and N-terminal domain of PNMA5 is required for interaction with MOAP-1. Furthermore, co-expression of PNMA5 and MOAP-1 in MCF-7 cells significantly enhanced chemo-sensitivity of MCF-7 to Etoposide treatment, indicating that PNMA5 and MOAP-1 interact synergistically to promote apoptotic signaling in MCF-7 cells.
CONCLUSIONS: Our results show that PNMA5 promotes apoptosis signaling in HeLa and MCF-7 cells and interacts synergistically with MOAP-1 through its N-terminal domain to promote apoptosis and chemo-sensitivity in human cancer cells. The C-terminal domain of PNMA5 is required for nuclear localization; however, both N-and C-terminal domains of PNMA5 appear to be required for pro-apoptotic function.
NEW METHOD: In this study the presence of reactive astrocytes and NG2 proteoglycans was investigated in two ex vivo models of SCI; stab injury and transection injury. Stereological analysis to measure immunohistochemical staining was performed on the scar and injury zones to detect astrocytes and the chondroitin sulphate proteoglycan NG2.
RESULTS: The volume fraction (Vv) of reactive astrocytes and NG2 proteoglycans increased significantly between day 3 and day 10 post injury in both ex vivo models. This data shows how ex vivo SCI models are a useful research tool allowing reduction of research cost and time involved in carrying out animal studies, as well as reducing the numbers of animals used.
COMPARISON WITH EXISTING METHOD: This is the first evidence of an ex vivo stab injury model of SCI and also the first comparison of immunohistochemical staining for injury markers within stab injured and transection injured ex vivo slice cultures.
CONCLUSIONS: The use of organotypic slice culture models provide a simple way to study the cellular consequences following SCI and they can also be used as a platform for potential therapeutics regimes for the treatment of SCI.