1.Lipopolysaccharide-induced Autophagy Increases SOX2-positive Astrocytes While Decreasing Neuronal Differentiation in the Adult Hippocampus
Wen-Chung LIU ; Chih-Wei WU ; Mu-Hui FU ; You-Lin TAIN ; Chih-Kuang LIANG ; I-Chun CHEN ; Chun-Ying HUNG ; Yu-Chi LEE ; Kay L.H. WU
Experimental Neurobiology 2022;31(5):307-323
Inflammation alters the neural stem cell (NSC) lineage from neuronal to astrogliogenesis. However, the underlying mechanism is elusive. Autophagy contributes to the decline in adult hippocampal neurogenesis under E. coli lipopolysaccharide (LPS) stimulation. SRY-box transcription Factor 2 (SOX2) is critical for NSC self-renewal and proliferation. In this study, we investigated the role of SOX2 in induced autophagy and hippocampal adult neurogenesis under LPS stimulation. LPS (5 ng•100 g -1 •hour -1 for 7 days) was intraperitoneally infused into male Sprague–Dawley rats (8 weeks old) to induce mild systemic inflammation. Beclin 1 and autophagy protein 12 (Atg12) were significantly upregulated concurrent with decreased numbers of Ki67- and doublecortin (DCX)-positive cells in the dentate gyrus. Synchronically, the levels of phospho(p)-mTOR, the p-mTOR/mTOR ratio, p-P85s6k, and the p-P85s6k/P85s6k ratio were suppressed. In contrast, SOX2 expression was increased. The fluorescence micrographs indicated that the colocalization of Beclin 1 and SOX2 was increased in the subgranular zone (SGZ) of the dentate gyrus. Moreover, increased S100β-positive astrocytes were colocalized with SOX2 in the SGZ. Intracerebroventricular infusion of 3-methyladenine (an autophagy inhibitor) effectively prevented the increases in Beclin 1, Atg12, and SOX2. The SOX2 + -Beclin 1 + and SOX2 + -S100β + cells were reduced. The levels of p-mTOR and p-P85s6k were enhanced. Most importantly, the number of DCX-positive cells was preserved. Altogether, these data suggest that LPS induced autophagy to inactivate the mTOR/P85s6k pathway, resulting in a decline in neural differentiation. SOX2 was upregulated to facilitate the NSC lineage, while the autophagy milieu could switch the SOX2-induced NSC lineage from neurogenesis to astrogliogenesis.
2.Developmental programming of the metabolic syndrome: Next-generation sequencing analysis of transcriptome expression in a rat model of maternal high fructose intake.
Yung-Mei CHAO ; You-Lin TAIN ; Steve LEU ; Kay L H WU ; Wei-Chia LEE ; Julie Y H CHAN
Acta Physiologica Sinica 2016;68(5):557-567
Excessive fructose intake is related to a high prevalence of metabolic syndrome, while little attention has been paid to the impact of maternal high-fructose (HF) intake on the development of metabolic syndrome and organ-specific transcriptome alterations in the offspring. We utilized RNA next-generation sequencing (NGS) technology to analyze the transcriptome expression in four organs (kidney, brain, heart, and urinary bladder) from 1-day, 3-week, and 3-month-old male offspring exposed to maternal HF diet. Maternal HF induced various phenotypes of metabolic syndrome in adult male offspring. We observed that maternal HF exposure induces long-term alterations of gene expression in the brain, heart, kidney, and urinary bladder in adult offspring. Different organs do not respond similarly to maternal HF intake. We found that changes in expression of Errfi1 and Ctgf were shared by four organs at 1 day of age. Also, a number of genes regulating fructose metabolism, glycolysis/gluconeogenesis, fatty acid metabolism, and insulin signalling appear to be regulated by maternal HF intake in different organs at 1 day of age. Our NGS results are of significance to the development of maternal interventions in the prevention of maternal HF-induced organ-specific programming, in order to reduce the global burden of metabolic syndrome.
Animals
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Female
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Fructose
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Kidney
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Lipid Metabolism
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Male
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Metabolic Syndrome
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Pregnancy
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Rats
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Rats, Sprague-Dawley
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Transcriptome