Although clinical evidence suggests that nonalcoholic fatty liver disease is an established major risk factor for heart failure, it remains unexplored whether sleep disorder-caused hepatic damage contributes to the development of cardiovascular disease (CVD). Here, our findings revealed that sleep fragmentation (SF) displayed notable hepatic detrimental phenotypes, including steatosis and oxidative damage, along with significant abnormalities in cardiac structure and function. All these pathological changes persisted even after sleep recovery for 2 consecutive weeks or more, displaying memory properties. Mechanistically, persistent higher expression of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) in the liver was the key initiator of SF-accelerated damage phenotypes. SF epigenetically controlled the acetylation of histone H3 lysine 27 (H3K27ac) enrichment at the Nox4 promoter and markedly increased Nox4 expression in liver even after sleep recovery. Moreover, fine coordination of the circadian clock and hepatic damage was strictly controlled by BMAL1-dependent Sirtuin 1 (Sirt1) transcription after circadian misalignment. Accordingly, genetic manipulation of liver-specific Nox4 or Sirt1, along with pharmacological intervention targeting NOX4 (GLX351322) or SIRT1 (Resveratrol), could effectively erase the epigenetic modification of Nox4 by reducing the H3K27ac level and ameliorate the progression of liver pathology, thereby counteracting SF-evoked sustained CVD. Collectively, our findings may pave the way for strategies to mitigate myocardial injury from persistent hepatic detrimental memory in diabetic patients.

A major obstacle in type 2 diabetes mellitus (T2DM) is sleep fragmentation (SF), which negatively affects testicular function. However, the underlying mechanisms remain to be elucidated. In this study, we demonstrate that SF induces testicular damage through a mechanism involving lipid metabolism, specifically mediated by melatonin (MEL) receptor 1a (MT1). T2DM mice with SF intervention displayed several deleterious phenotypes such as apoptosis, deregulated lipid metabolism, and impaired testicular function. Unexpectedly, sleep recovery (SR) for 2 consecutive weeks could not completely abrogate SF's detrimental effects on lipid deposition and testicular function. Interestingly, MEL and MT1 agonist 2-iodomelatonin (2IM) effectively improved lipid homeostasis, highlighting MEL/2IM as a promising therapeutic drug for SF-trigged testicular damage. Mechanistically, MEL and 2IM activated FGFR1 and sequentially restrained the crosstalk and physical interaction between TAB1 and TAK1, which ultimately suppressed the phosphorylation of TAK1 to block lipid deposition and cell apoptosis caused by SF. The ameliorating effect of MEL/2IM was overtly nullified in Fgfr1 knockout (Fgfr1-KO ^+/- ) diabetic mice. Meanwhile, testicular-specific overexpression of Tak1 abolished the protective effect of FGF1^mut on diabetic mouse testis. Our findings offer valuable insights into the molecular mechanisms underlying the testicular pathogenesis associated with SF and propose a novel therapeutic approach for addressing male infertility in T2DM.