title: Nitric oxide synthase mediates PC12 differentiation induced by the surface topography of nanostructured TiO2.
abstract: BACKGROUND
  Substrate nanoscale topography influences cell proliferation and differentiation through mechanisms that are at present poorly understood. In particular the molecular mechanism through which cells 'sense' and adapt to the substrate and activate specific intracellular signals, influencing cells survival and behavior, remains to be clarified.
  
  
  RESULTS
  To characterize these processes at the molecular level we studied the differentiation of PC12 cells on nanostructured TiO2 films obtained by supersonic cluster beam deposition.Our findings indicate that, in PC12 cells grown without Nerve Growth Factor (NGF), the roughness of nanostructured TiO2 triggers neuritogenesis by activating the expression of nitric oxide synthase (NOS) and the phospho-extracellular signal-regulated kinase 1/2 (pERK1/2) signaling. Differentiation is associated with an increase in protein nitration as observed in PC12 cells grown on flat surfaces in the presence of NGF. We demonstrate that cell differentiation and protein nitration induced by topography are not specific for PC12 cells but can be regarded as generalized effects produced by the substrate on different neuronal-like cell types, as shown by growing the human neuroblastoma SH-SY5Y cell line on nanostructured TiO2.
  
  
  CONCLUSIONS
  Our data provide the evidence that the nitric oxide (NO) signal cascade is involved in the differentiation process induced by nanotopography, adding new information on the mechanism and proteins involved in the neuritogenesis triggered by the surface properties.
authors.affiliation: CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, Milano 20133, Italy. paolo.milani@mi.infn.it.
authors.forename: Margherita
authors.initials: M
authors.lastname: Tamplenizza
authors.forename: Cristina
authors.initials: C
authors.lastname: Lenardi
authors.forename: Elisa
authors.initials: E
authors.lastname: Maffioli
authors.forename: Simona
authors.initials: S
authors.lastname: Nonnis
authors.forename: Armando
authors.initials: A
authors.lastname: Negri
authors.forename: Stefania
authors.initials: S
authors.lastname: Forti
authors.forename: Elisa
authors.initials: E
authors.lastname: Sogne
authors.forename: Silvia
authors.initials: S
authors.lastname: De Astis
authors.forename: Michela
authors.initials: M
authors.lastname: Matteoli
authors.forename: Carsten
authors.initials: C
authors.lastname: Schulte
authors.forename: Paolo
authors.initials: P
authors.lastname: Milani
authors.forename: Gabriella
authors.initials: G
authors.lastname: Tedeschi
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D005786:Gene Expression Regulation; D006801:Humans; D040542:Mechanotransduction, Cellular; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism; D020932:Nerve Growth Factor / Q000494:pharmacology; D016501:Neurites / Q000378:metabolism / Q000648:ultrastructure; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry* / Q000494:pharmacology; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; C009495:titanium dioxide; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D020932:Nerve Growth Factor; D014025:Titanium; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3