Integrated transcriptomic profiling combined with in vitro validation reveals the involvement of TMEM140 in the link between periodontitis and brain aging

Objective: RNA interference assays, and to further assess the role of TMEM140 in linking PD to brain aging. Methods: lipopolysaccharide (PG-LPS)-induced inflammatory model in human gingival fibroblasts (HGFs) and an Aβ1-42 and D-galactose-induced senescence model in SH-SY5Y neuron-like cells were established; TMEM140 in SH-SY5Y cells was then silenced using small interfering RNA (siRNA), and the neuron-like cells were treated with the same batch of standardized conditioned medium (CM; prepared from the supernatant of PG-LPS-treated HGFs) to observe changes in cellular responses to inflammatory stimulation after TMEM140 downregulation. Results: experiments demonstrated that PG-LPS treatment markedly increased TMEM140 expression in HGFs, whereas treatment with Aβ1-42 and D-galactose reduced TMEM140 expression in neuron-like cells. When exposed to the same batch of conditioned medium, neuron-like cells with TMEM140 knockdown displayed more evident injury and senescence-related phenotypes, including reduced cell viability, increased reactive oxygen species (ROS) production, a higher percentage of senescence-associated β-galactosidase (SA-β-Gal)-positive cells, and marked upregulation of IL-1β, IL-6, TNF-α, p16, p21, RELA, NFKBIA, and TP53, indicating that reduced TMEM140 expression may contribute to enhanced susceptibility of neuron-like cells to inflammatory stress. Conclusion: experimental validation, this study indicates that TMEM140 may be a candidate bridge molecule connecting PD and AD comorbidity. TMEM140 may participate in shaping the peripheral-central immunosenescence network and contribute to the cross-system transmission of inflammatory signaling.