Basical Researches
Effects of brain-specific knockout of Sirt6 gene on cerebral cortex in aged mice
Wang Xinhuan, Hou Lin, Yin Bin, Liu Wei, Peng Xiaozhong
Published 2021-06-20
Cite as Chin J Behav Med & Brain Sci, 2021, 30(6): 481-488. DOI: 10.3760/cma.j.cn371468-20210225-00106
Abstract
ObjectiveTo study the effect of senescence gene silent information regulator 6 (Sirt6) knockout on the brain of aged mice.
MethodsSirt6-flox transgenic mice were constructed, and the mouse brain tissue was specifically knocked out by Emx1-Cre tool mice.According to genotyping, 11 wild-type mice were selected as control group(WT group) and 10 Sirt6 gene konckout mice were selected as conditional knockout group(cKO group). Body size and body weight of the aged mice were measured and cerebral cortex thickness was measured by HE staining.Brain neurogenesis was analyzed with EdU markers.The expression of RNA-binding protein HuR and apoptosis-related protein Caspase-3 were detected by Western blot.Meanwhile, histone acetylation levels in the cortex were detected.
ResultsSirt6 brain tissue-specific knocked out mice were successfully constructed.Compared with the brain tissue area((2.07±0.22) cm2)and cortical thickness ((970.56±80.91) μm) of WT mice in the 12-month-old group, the brain tissue area ((1.61±0.14)cm 2) and cortical thickness ((822.88±53.94) μm) in Sirt6 cKO group were smaller, and the differences were statistically significant (both P<0.05). EdU incorporation into nerve cells showed that the number of EdU incorporation into periventricular nerve cells in cKO group was lower ((4.75±1.48)) than that in WT group ((10.29±1.93)). The difference was statistically significant (P<0.001). In the experiment of 17 months age group, mice in cKO group were smaller in body size, lower in body weight ((29.00±1.08) g) and smaller in brain area ((1.54±0.55)cm2)compared with WT group in body size, body weight ((35.25±4.17) g) and brain tissue area ((1.98±0.18) cm2)(both P<0.05). The expression of Caspase-3 and HuR in cortical proteins of these two age groups decreased(t=2.95, 5.38, both P<0.05), and the expression of H3K9ac and H3K56ac increased(t=3.53, 2.78, both P<0.05), but the expression of Sirt1 homologous gene remained unchanged(t=1.26, P>0.05).
ConclusionThe specific deletion of Sirt6 in brain tissue can lead to the decrease of brain neurogenesis in aged mice, and the aggravation of aging and the increase of apoptosis, which may be the reason for the thinning of cerebral cortex and brain tissue atrophy.The molecular mechanism is speculated to be related to the increase of acetylation level after Sirt6 knockout
Key words:
Silent information regulator 6; Conditional gene knockout; Histone acetylation; Neurogenesis; Aging
Contributor Information
Wang Xinhuan
State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
Hou Lin
State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
Yin Bin
State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
Liu Wei
State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
Peng Xiaozhong
State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, China
Institute of Medical Biology, Chinese Academy of Medical Sciences, Peking Union Medical College, Kunming 650118, China
