Aging Triggers an Intestinal Energy Crisis and HDL3 Deficiency Disrupting Gut-Liver Axis Homeostasis.

Li, Yumeng; Bao, Tongtong; Gao, Lumin; Tian, Xutong; Xue, Junyu; Jin, Caike; Wang, Shujin; Wu, Xin · Aging Cell · 2026

basic_science · Level V

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Abstract

During aging, decreased intestinal barrier function and its ability to synthesize metabolites are closely associated with various age-related diseases. However, the mechanism by which impaired intestinal synthesis contributes to gut-liver axis aging remains unclear. This study reveals that aging induces a mitochondrial energy crisis and defective membrane localization of ABCA1, significantly inhibiting the biosynthesis of high-density lipoprotein 3 (HDL3) in the intestine. Exogenous supplementation with β-nicotinamide mononucleotide (NMN) restores intestinal NAD<sup>+</sup> homeostasis, enhances oxidative phosphorylation efficiency, and promotes ATP-dependent lipid transport, thereby rejuvenating the production of gut-derived HDL3. Further investigations demonstrate that gut-originated HDL3 neutralizes lipopolysaccharide (LPS) in the liver and attenuates TLR4-mediated inflammatory cascades, ultimately ameliorating age-related liver injury. These findings elucidate a novel mechanism whereby NMN modulates the NAD<sup>+</sup>-mitochondria-ABCA1-HDL3 axis to preserve gut-liver axis function, offering a promising therapeutic strategy for mitigating aging-related pathologies in this metabolic cross-talk.

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