MicroRNA-19a Targets Fibroblast Growth Factor-Inducible Molecule 14 and Prevents Tubular Damage in Septic AKI

Abstract

<jats:p>Fibroblast growth factor-inducible molecule 14 (Fn14) plays a principal role in triggering tubular damage during septic acute kidney injury (AKI). Here, we explore the mechanism underlying Fn14 deregulation in septic AKI. We identify Fn14 as a bona fide target of miR-19a, which directly binds to 3<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:msup><mml:mrow /><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msup></mml:math> UTR of Fn14 for repression independent of cylindromatosis (CYLD), the deubiquitinase (DUB) downstream of miR-19a, and thereby antagonizes the LPS-induced tubular cell apoptosis. Genetic ablation of Fn14, but not of CYLD, abolishes the ability of miR-19a to antagonize the tubular apoptosis by lipopolysaccharide (LPS). In mice, systemic delivery of miR-19a confers protection against septic AKI. Our findings implicate that miR-19a may serve as a promising therapeutic candidate in the prevention of septic AKI.</jats:p>

Interruption of neutrophil extracellular traps formation dictates host defense and tubular HOXA5 stability to augment efficacy of anti-Fn14 therapy against septic AKI

“…Kidney tissues were excised from mice, fixed in 10% formalin, decalcified in 10% EDTA and embedded in paraffin for hematoxylin&eosin (H&E) and immunohistochemical staining as described in previous publications 17 , 18 , 20 . For immunohistochemical staining, renal sections were rehydrated and subjected to the heat-mediated antigen retrieval using citrate buffer (pH 6.0).…”

“…Human kidney proximal tubular epithelial (HK-2) cells were grown in RPMI-1640 (GIBCO, Carlsbad, CA) with 10% heat-inactivated FBS, 2 mM glutamine, 100 U/mL penicillin, and 100 g/mL streptomycin in a humidified incubator with 5% CO 2 at 37 °C as previously described 17 , 18 , 20 . Renal proximal tubular cells (RPTCs) were isolated from the indicated mice using a previously described procedure with minor modifications 19 .…”

“…Protein extraction and western blotting analyses were carried out as described in previous publications 17 , 18 , 20 - 22 . For protein isolation in tissues, septic mice receiving various therapies were sacrificed 1 h before kidneys harvested and snap frozen in liquid nitrogen at -80 °C.…”

“…The procedures of RNA extraction and RT-qPCR were described previously 18 , 20 , 22 , 23 . In brief, cells in culture were lysed in Trizol (Life technology, CA) following medium removal.…”

“…Our recent research demonstrated that tubular Fn14 is upregulated during abdominal sepsis and, pharmacological deactivation of tubular cell-intrinsic Fn14 by ITEM-2, an anti-Fn14 monoclonal antibody (mAb), prolongs survival of mice and protects them against septic AKI 17 . Systemic delivery of microRNA-19a mimics into cecal ligation and puncture (CLP) and the LPS-induced endotoxemia (LIE) mice downregulates tubular cell-intrinsic Fn14 expression, thereby impairing AKI development 18 . These evidences underscore that Fn14 might be a promising therapeutic target for septic AKI.…”