TIFA protein expression is associated with pulmonary arterial hypertension

NSUN3 Aggravates Sepsis-Associated Acute Kidney Injury by Stabilising TIFA mRNA Through m5C

BACKGROUND

Acute kidney injury (AKI) is a common complication of sepsis and also a risk factor for progression of chronic kidney disease. NOP2/Sun RNA methyltransferase 3 (NSUN3) is involved in the regulation of sepsis progression. However, the mechanism by which NSUN3 regulates sepsis-associated AKI (SA-AKI) remains unclear.

METHODS

SA-AKI mouse model and lipopolysaccharide (LPS)-induced injury model in HK-2 cells were constructed. Haematoxylin-eosin staining, quantitative polymerase chain reaction (qPCR), western blotting, cell counting kit 8, flow cytometry, 2',7'-dichlorofluorescein diacetate, enzyme-linked immunosorbent assay, methylation RNA immunoprecipitation-qPCR, actinomycin D and TdT-mediated dUTP Nick-End Labelling staining assays were utilised to explore the expression and related mechanism of NSUN3 in the SA-AKI models.

RESULTS

The expression of NSUN3 and tumour necrosis factor receptor-associated factor (TRAF)-interacting protein with forkhead-associated domain (TIFA) was upregulated in mice with SA-AKI and LPS-induced HK-2 cells. Knockdown of NSUN3 inhibited LPS-induced injury in HK-2 cells. Mechanically, NSUN3 increased TIFA mRNA stability and upregulated its expression through m5C modification. Moreover, knockdown of NSUN3 was found to alleviate LPS-induced HK-2 cell injury and SA-AKI in mice by reducing TIFA expression.

CONCLUSION

NSUN3 aggravates SA-AKI by stabilising TIFA mRNA through m5C, indicating that NSUN3 may be a biomarker for SA-AKI.

TIFA contributes to periodontitis in diabetic mice via activating the NF‑κB signaling pathway

Diabetic periodontitis (DP) refers to destruction of periodontal tissue and absorption of bone tissue in diabetic patients. Tumor necrosis factor receptor‑associated factor (TRAF)‑interacting protein with forkhead‑associated domain (TIFA) as a crucial regulator of inflammation activates the NF‑κB signaling pathway to regulate cell biological behavior. However, the function and mechanism of TIFA on DP suffer from a lack of research. In the present study, TIFA was upregulated in the periodontal tissue of a DP mouse model. In addition, the expression of TIFA in RAW264.7 cells was induced by high glucose (HG) culture and increased by lipopolysaccharide (LPS) from Porphyromonas gingivalis treatment in a time‑dependent manner. Knockdown of TIFA significantly reduced the levels of inflammatory cytokines, including TNF‑α, IL‑6, IL‑1β and monocyte chemoattractant protein‑1, in HG and LPS‑induced RAW264.7 cells. The nuclear translocation of NF‑κB p65 was induced by HG and LPS and was clearly suppressed by absence of TIFA. The expression of downstream factors Nod‑like receptor family pyrin domain‑containing 3 and apoptosis‑associated speck‑like protein was inhibited by silencing TIFA. Moreover, TIFA was increased by receptor activator of NF‑κB (RANK) ligand (RANKL) in a concentration dependent manner. The expression of cathepsin K, MMP9 and nuclear factor of activated T cells cytoplasmic 1 was downregulated by depletion of TIFA. RANKL‑induced osteoclast differentiation was inhibited by silencing of TIFA. Meanwhile, the decrease of TIFA blocked activation of the NF‑κB pathway in RANKL‑treated RAW264.7 cells. In conclusion, TIFA as a promoter regulates the inflammation and osteoclast differentiation via activating the NF‑κB signaling pathway.