RESUMEN
Cytokines are the primary mediators of age-related disorders. The IL-17/IL-10 axis plays a crucial role in bone destruction and neuro-inflammation. Additionally, a new Th2 cytokine-IL-33-has gained attention for its potential implications in aging-associated conditions. However, the involvement of IL-33 in aging-mediated bone loss and memory impairment remains unclear and needs further investigation. This study reveals the impact of IL-33 on various aspects of the immune system, bone health, and neural functions. To induce senescence, we used d-galactose for its convenience and fewer side effects. The experimental design involved treating 20-week-old C57BL/6J mice with d-galactose subcutaneously for 10 weeks to induce aging-like effects. Thereafter, IL-33 recombinant protein was administered intraperitoneally for 15 days to evaluate its impact on various immune, skeletal, and neural parameters. The results demonstrated that d-galactose-induced aging led to bone loss and compromised osteogenic parameters, accompanied by increased oxidative stress and neurodegeneration in specific brain regions. Behavioral activities were also affected. However, supplementation with IL-33 mitigated these effects, elevating osteogenic parameters and reducing senescence markers in osteoblast cells in an aging mouse model and exerted neuroprotective potential. Notably d-galactose-induced aging was characterized by high bone turnover, reflected by altered serum levels of CTX, PTH, beta-galactosidase, and P1NP. IL-33 treatment attenuated these effects, suggesting its role in regulating bone metabolism. Furthermore, d-galactose-induced aging was associated with increased differentiation of Th17 cells and upregulation of associated markers, such as STAT-3 and ROR-γt, while downregulating Foxp3, which antagonizes Th17 cell differentiation. IL-33 treatment countered these effects by suppressing Th17 cell differentiation and promoting IL-10-producing T-regulatory cells. Overall, these findings provide insights into the potential therapeutic implications of IL-33 in addressing aging-induced bone loss and memory impairment.
RESUMEN
X-linked hypophosphatemia (XLH), an inheritable form of rickets is caused due to mutation in Phex gene. Several factors are linked to the disease's aetiology, including non-coding RNA molecules (miRNAs), which are key post-transcriptional regulators of gene expression and play a significant role in osteoblast functions. MicroRNAs sequence analysis showed differentially regulated miRNAs in phex silenced osteoblast cells. In this article, we report miR-539-3p, an unidentified novel miRNA, in the functional regulation of osteoblast. MiR-539-3p overexpression impaired osteoblast differentiation. Target prediction algorithm and experimental confirmation by luciferase 3' UTR reporter assay identified LRP-6 as a direct target of miR-539-3p. Over expression of miR-539-3p in osteoblasts down regulated Wnt/beta catenin signaling components and deteriorated trabecular microarchitecture leading to decreased bone formation in ovariectomized (Ovx) mice. Additionally, biochemical bone resorption markers like CTx and Trap-5b were elevated in serum samples of mimic treated group, while, reverse effect was observed in anti-miR treated animals along with increased bone formation marker P1NP. Moreover, transcriptome analysis with miR-539-3p identified a novel uncharacterized Akap-3 gene in osteoblast cells, knock down of which resulted in downregulation of osteoblast differentiation markers at both transcriptional and translational level. Overall, our study for the first time reported the role of miR-539-3p in osteoblast functions and its downstream Akap-3 signalling in regulation of osteoblastogenesis.