DNA Demethylation of Promoter Region Facilitates Atoh-1-Induced Interleukin-19 Expression Activation in Bone Marrow Monocytes of Old Mice.

With increasing age, there is a notable increase in the differentiation of bone marrow-derived mononuclear cells (BMMs) into osteoclasts, accompanied by a concurrent rise in both osteoclast quantity and activity. This escalation in osteoclastic activity accelerates bone resorption, which in turn contributes to age-related bone loss and metabolic bone disorders, notably osteoporosis. Our study confirms that elevated IL-19 expression promotes aging-induced bone loss in aged mice and sheds light on the regulatory mechanisms upstream of IL-19 expression and secretion. Primarily, it is the methylation status of the IL-19 gene's promoter region that impacts Atonal BHLH Transcription Factor 1 (Atoh1)'s ability to bind to the promoter. We found that this specific mechanism involves reduced expression and binding affinity of Dnmt1 to the IL-19 promoter region. The findings of our study suggest that targeting IL-19 could be a potential strategy for managing bone loss-related conditions and enhance the current understanding of how DNA methylation levels contribute to age-related bone loss.

[Effects of Honokiol on cognitive function in mice with kainic acid-induced epilepsy].

OBJECTIVE: To investigate the effects of Honokiol on cognitive function in mice with epilepsy. METHODS: Kainic acid (38 mg/kg) was intraperitoneally injected in 5 weeks old male ICR mice to induce epilepsy. Honokiol at dose of 3, 10, 30 mg/kg was given to epilepic mice by intraperitoneal injection for 10 days. Fluoro-Jade B staining was used to assess neuronal death; Morris water maze and Y maze tests were used to measure cognitive function such as learning and memory; Western blot was performed to detect the expression of acetylated superoxide dismutase (SOD), microtubule associated protein 1 light chain 3-Ⅱ (LC3-Ⅱ) and P62 in hippocampus tissue; thiobarbituric acid and WST-1 methods were used to detect malondialdehyde (MDA) and SOD. RESULTS: Compared with control group, the levels of acetylated-SOD, MDA, LC3-Ⅱ, P62 and neuronal death increased, cognitive function and SOD decreased in model group (P<0.05 or P<0.01). Honokiol at the dose of 10 mg/kg and 30 mg/kg decreased SOD acetylation, MDA content, expression of LC3-Ⅱ and P62, as well as neuronal death, and the cognitive function was improved (P<0.05 or P<0.01), especially in 30 mg/kg Honokiol group. CONCLUSIONS: Honokiol alleviates oxidative stress and autophagy degradation disorder, decreases neuronal death, and therefore improves cognitive function in epilepsy mice.