Abbreviations: THP: Tamm-Horsfall protein; TLR4: Toll-like receptor 4; AKI: acute kidney injury; TAL: thick ascending limb; MIP-2: macrophage inflammatory protein-2; IFN-γ: interferon-gamma, IL1α: interleukin 1 alpha, TNF-α: tumor necrosis factor-alpha; IL6: interleukin 6, CXCL1: chemokine (C-X-C motif) ligand 1; IL13: interleukin 13; C3b: complement factor 3b; ICU: intensive care unit; VLBW: very low birth weight; CKD: chronic kidney disease; eGFR: estimated glomerular filtration rate; CPB: cardiopulmonary bypass; CCr: creatinine clearance rate. Here, TLR4 is linked to acute kidney injury.