title: PTEN-mediated Akt activation in human neocortex during prenatal development.
abstract: Akt is a crucial factor for cell survival and migration. Phosphatase and tensin (PTEN) negatively regulates cell growth and survival by inhibiting PI3K-dependent signaling. PTEN also blocks Akt phosphorylation, a main downstream molecule of PI3K cascade. So far, no studies have shown PTEN expression and Akt phosphorylation levels in the developing human neocortex. Our hypothesis is that spatial and temporal expression of PTEN is likely to modulate developing human brain cortical modeling by regulating Akt activation. Therefore, our aim is to analyze the expression pattern of PTEN and phospho-Akt levels using immunohistochemistry, Western blot, and semiquantitative analysis in the developing human neocortex (n=13 fetuses from first, second, and third trimesters). PTEN expression was decreased parallel to development, but some cells revealed strong nuclear immunoreactivity in the developing neocortex while the active Akt level was increased. Double immunohistochemistry was performed for proliferating cell nuclear antigen (PCNA)-Tuj1 (as neuronal marker) and PCNA-GFAP (Glial marker) to the subsequent sections of PTEN and Akt-stained slides. PCNA (+) cells were mostly positive for glial fibrillary acidic protein (GFAP) and correlated with active-Akt immunoreactivity. Our results suggest that Akt-mediated signaling plays an active role in cell migration, survival, and cerebral cortical modeling throughout prenatal life and that PTEN is the most likely protein to regulate this signaling.
authors.affiliation: Department of Histology and Embryology, Akdeniz University, Antalya, 07070, Turkey.
authors.forename: Gamze
authors.initials: G
authors.lastname: Tanriover
authors.forename: Necdet
authors.initials: N
authors.lastname: Demir
authors.forename: Elif
authors.initials: E
authors.lastname: Pestereli
authors.forename: Ramazan
authors.initials: R
authors.lastname: Demir
authors.forename: Umit A
authors.initials: UA
authors.lastname: Kayisli
mesh_terms: D015153:Blotting, Western; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D019579:Neocortex / Q000196:embryology / Q000378:metabolism*; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D014404:Tubulin / Q000032:analysis; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D018809:Proliferating Cell Nuclear Antigen; D011518:Proto-Oncogene Proteins; D014404:Tubulin; D025521:Tumor Suppressor Proteins; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human