The Biomarker TCONS_00016233 Drives Septic AKI by Targeting the miR-22-3p/AIFM1 Signaling Axis

The prediction of mortality for septic acute kidney injury (AKI) has been assessed by a number of potential biomarkers, including long noncoding RNAs (lncRNAs). However, the validation of lncRNAs as biomarkers, particularly for the early stages of septic AKI, is still warranted. Our results indicate that the lncRNA TCONS_00016233 is upregulated in plasma of sepsis-associated non-AKI and AKI patients, but a higher cutoff threshold (9.5 × 10⁵, copy number) provided a sensitivity of 71.9% and specificity of 89.6% for the detection of AKI. The plasma TCONS_00016233 was highly correlated with serum creatinine, tissue inhibitor metalloproteinase-2 (TIMP-2), insulin-like growth factor binding protein-7 (IGFBP7), interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), C-reactive protein (CRP), and urinary TCONS_00016233. Lipopolysaccharide (LPS) induced the expression of lncRNA TCONS_00016233 via the Toll-like receptor 4 (TLR4)/p38 mitogen-activated protein kinase (MAPK) signal pathway in human renal tubular epithelial (HK-2) cells. Furthermore, TCONS_00016233 mediates the LPS-induced HK-2 cell apoptosis and the expression of IL-1β and TNF-α. Mechanistically, TCONS_00016233 acts as a competing endogenous RNA (ceRNA) to prevent microRNA (miR)-22-3p-mediated downregulation of the apoptosis-inducing factor mitochondrion-associated 1 (AIFM1). Finally, overexpression of TCONS_00016233 is capable of aggravating the LPS- and cecal ligation and puncture (CLP)-induced septic AKI by targeting the miR-22-3p/AIFM1 axis. Taken together, our data indicate that TCONS_00016233 may serve as an early diagnosis marker for the septic AKI, possibly acting as a novel therapeutic target for septic AKI.