Early high-sucrose diet exacerbates cognitive impairment in 3×Tg-AD mice via activating cGAS-STING pathway

Xi ZHANG; Hongyu CHEN; Jianhao WANG; Yuke SHI; Feng GAO; Yida LYU; Shuai DING; Xiang LI; Hang YU; Jiabei WANG; Zhihao WANG

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Early high-sucrose diet exacerbates cognitive impairment in 3×Tg-AD mice via activating cGAS-STING pathway

VernacularTitle:早期高糖饮食通过激活cGAS-STING通路介导3×Tg-AD小鼠认知障碍
Author: Xi ZHANG ¹ ; Hongyu CHEN ¹ ; Jianhao WANG ¹ ; Yuke SHI ¹ ; Feng GAO ¹ ; Yida LYU ¹ ; Shuai DING ¹ ; Xiang LI ¹ ; Hang YU ¹ ; Jiabei WANG ¹ ; Zhihao WANG ¹
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1. 武汉大学人民医院神经内科　武汉大学人民医院神经退行性疾病研究中心，武汉　430060
Publication Type:Journal Article
Keywords: High-sucrose diet; Cognitive impairment; Alzheimer's disease; Neuroinflammation; Innate immunity; cGAS-STING; Mitochondrial DNA
From: Chinese Journal of Neuromedicine 2025;24(9):873-887
CountryChina
Language:Chinese
Abstract: Objective:To investigate the effect of early high-sucrose diet (eHSD) on cognitive function and its regulatory mechanism in 3×Tg-AD mice.Methods:(1) Eighteen specific-pathogen-free (SPF)-grade 2-month-old wide-type (WT) mice were randomly divided into a WT+normal chow diet (NCD) group and a WT+eHSD group, with 9 mice in each group; and 18 SPF-grade 2-month-old 3×Tg-AD mice were randomly divided into a 3×Tg-AD+NCD group and a 3×Tg-AD+eHSD group, with 9 mice in each group. At 2-5 months old, mice in the 4 groups received standard laboratory food+purified water or 30% sucrose water, followed by standard feed for all groups. At 8 months old, cognitive function was assessed by Morris water maze test; fluorescent intensity of AT8 (phosphorylated [p]-tau) and T22 (tau oligomers) in the hippocampal tissues was detected by immunofluorescent staining; concentrations of β-amyloid protein (Aβ) 42 and Aβ 40 were detected by enzyme-linked immunosorbent assay (ELISA); protein expressions of stimulator of interferon genes (STING), TANK-binding kinase 1 (TBK1), p-TBK1, and CCAAT/enhancer-binding protein β (C/EBPβ) were detected by Western blotting; activity of C/EBPβ transcription factor was detected by activity assay; mitochondrial DNA (mtDNA) content in the cytoplasm of cell was detected by real-time quantitative PCR (qPCR). (2) Eighteen SPF-grade 2-month-old 3×Tg-AD mice were randomized into a 3×Tg-AD+eHSD+H-151 group and a 3×Tg-AD+eHSD+dimethyl sulfoxide (DMSO) group, with 9 mice in each group. Mice at 2-5 months old were given standard laboratory food+30% sucrose water; they were, respectively, injected intraperitoneally with STING pathway inhibitor H-151 or DMSO at 5 months old, and continually injected until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, Western blotting and C/EBPβ transcription factor activity experiments were repeated as before. (3) After crossing C/EBPβ heterozygous knockout (C/EBPβ +/-) mice with 3×Tg-AD mice, 3×Tg-AD/C/EBPβ +/- mice were obtained, and 3×Tg-AD mice were used as controls; they were named 3×Tg-AD/C/EBPβ +/-+eHSD group and 3×Tg-AD+eHSD group, with 9 mice in each group. Both groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old, followed by standard feed until 8 months old; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. (4) C/EBPβ transgenic mice (C/EBPβTg) were crossed with 3×Tg-AD mice to obtain C/EBPβTg/3×Tg-AD mice, and Non-Tg/3×Tg-AD mice were used as controls; they were, respectively, named as C/EBPβTg/3×Tg-AD+eHSD+H-151 group, Non-Tg/3×Tg-AD+eHSD+H-151 group, and Non-Tg/3×Tg-AD+eHSD+DMSO group, with 9 mice in each group. All 3 groups of mice were given standard laboratory food+30% sucrose water at 2-5 months old; at 5-8 months old, mice in the C/EBPβTg/3×Tg-AD+eHSD+H-151 group and Non-Tg/3×Tg-AD+eHSD+H-151 group were intraperitoneally injected with H-151, while mice in the Non-Tg/3×Tg-AD+eHSD+DMSO group were injected with DMSO; and then, the behavioral testing, immunofluorescent staining, ELISA, and Western blotting experiments were repeated as before. Results:(1) Compared with those in the WT+NCD group and WT+eHSD group, area under the latency curve of 3×Tg-AD+eHSD mice was significantly increased, and proportion of time spending in the targeted quadrant of mice in the 3×Tg-AD+NCD group and 3×Tg-AD+eHSD group was significantly decreased ( P<0.05); compared with that in the 3×Tg-AD+NCD group, proportion of time spending in the targeted quadrant in mice of the 3×Tg-AD+eHSD group was significantly reduced ( P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.076 vs. 2.902±0.399; T22 fluorescent intensity: 1.000±0.145 vs. 2.495±0.273; Aβ 42: 1.000±0.167 vs.1.956±0.132; Aβ 40: 1.000±0.226 vs.1.900±0.116), significantly increased C/EBPβ protein expression and C/EBPβ transcription factor activity (1.000±0.164 vs. 1.804±0.112; 1.000±0.216 vs. 2.743±0.301), and statistically increased mtDNA level detected by D-loop1 and D-loop3 (1.000±0.234 vs. 2.800±0.210; 1.000±0.155 vs. 2.952±0.078; P<0.05). Compared with the 3×Tg-AD+NCD group, the 3×Tg-AD+eHSD group had significantly increased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.192 vs. 2.093±0.081; p-TBK1/TBK1: 1.000±0.148 vs. 1.561±0.112, P<0.05). (2) Compared with the 3×Tg-AD+eHSD+DMSO group, the 3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers expressions, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.142 vs. 0.538±0.057; T22 fluorescent intensity: 1.000±0.104 vs. 0.665±0.088; Aβ 42: 1.000±0.084 vs. 0.600±0.007; Aβ 40: 1.000±0.138 vs. 0.476±0.083), significantly decreased STING protein expression and p-TBK1/TBK1 ratio (STING: 1.000±0.054 vs. 0.468±0.111; p-TBK1/TBK1: 1.000±0.057 vs. 0.598±0.090), and significantly decreased C/EBPβ transcription factor activity (1.000±0.097 vs. 0.445±0.106; P<0.05). (3) Compared with the 3×Tg-AD+eHSD group, the 3×Tg-AD/C/EBPβ +/-+eHSD group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, significantly decreased p-tau and tau oligomers, Aβ 42 and Aβ 40 concentrations in the hippocampus (AT8 fluorescent intensity: 1.000±0.160 vs. 0.506±0.065; T22 fluorescent intensity: 1.000±0.127 vs. 0.346±0.048; Aβ 42: 1.000±0.017 vs. 0.510±0.101; Aβ 40: 1.000±0.098 vs. 0.586±0.153), and significantly decreased C/EBPβ protein expression (1.000±0.101 vs. 0.568±0.094; P<0.05). (4) Compared with the Non-Tg/3×Tg-AD+eHSD+DMSO group, the Non-Tg/3×Tg-AD+eHSD+H-151 group had significantly decreased area under the latency curve, significantly increased proportion of time spending in the targeted quadrant, and significantly decreased p-tau and tau oligomers expressions, Aβ 40 concentration in the hippocampus, and the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly decreased STING protein expression and p-TBK1/TBK1 ratio in the hippocampus ( P<0.05). Compared with the Non-Tg/3×Tg-AD+eHSD+H-151 group, the C/EBPβTg/3×Tg-AD+eHSD+H-151 group had significantly increased area under the latency curve, significantly decreased proportion of time spending in the targeted quadrant, and significantly increased p-tau and tau oligomers expressions, Aβ 40 and Aβ 42 concentration in the hippocampus ( P<0.05). Conclusion:The eHSD aggravates cognitive impairment in 3×Tg-AD mice through activating cGAS-STING-C/EBPβ pathway.