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P3‐365: Deficits in mitochondrial bioenergetics and mitochondrial beta‐amyloid deposition in brain are associated with reproductive senescence and loss of ovarian hormones: Prevention by estradiol
Author(s) -
Yao Jia,
Irwin Ronald,
Chen Shuhua,
Brinton Roberta D.
Publication year - 2010
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2010.05.1907
Subject(s) - bioenergetics , endocrinology , mitochondrion , oxidative stress , medicine , biology , lipid peroxidation , senescence , mitochondrial biogenesis , oxidative phosphorylation , microbiology and biotechnology , biochemistry
gestation were immortalized with telomeras (named hSN12W-TERT cells). After exposed to 1mM RA for 3, 5, 7days, the properties of hSN12WTERT cells were characterized by using microscopy, flow cytometry analysis (FACS), immunocytochemistry, RT-PCR and Western Blot. Results: After 3 days’ treatment with RA, hSN12W-TERT cells showed phenotypical changes, assuming a neuronal-like morphology with contemporaneous formation of dendritic-like structures. Mature neuronal-like morphology was observed after exposed to RA for 7 days. FACS analysis showed 77.25% of proliferating hSN12W-TERT cells were in G1/G0-phase while 9.38% of cells in S-phase. Following RA treatment, cell growth was arrested, and 85.68% of cells accumulated in G1/G0-phase while 8.57% of cells in S-phase. p27 mRNA was elevated after exposed to RA for 3 days. Immunocytochemistry and Western Blot demonstrated that the levels of p27 in hSN12W-TERT cells increased following 3 days’ treatment with RA compared with those of untreated cells, with a peak at 5 days (p < 0.05). The expression of Cdk2 didn’t change following RA treatment while the expression of p-Cdk2, which represented the activity of Cdk2, decreased significantly in response to RA treatment. S-phase kinase-associated protein 2 (Skp2), which was required for the ubiquitin-mediated degradation of p27, was detected in proliferating hSN12W-TERT cells and decreased dramaticly in response to RA treatment in a time-dependent manner. Conclusions: There is a functional link between RA and p27 function in control of neuronal differentiation in hSN12W-TERT cells. High levels of p27 are regulated not only by increased p27 mRNA expression but also by inhibiting its degradation through reducing proteasome-dependent proteolysis.