PHLDA1 knockdown inhibits inflammation and oxidative stress by regulating JNK/ERK pathway, and plays a protective role in sepsis-induced acute kidney injury

Abstract

Background: Acute kidney injury (AKI), a prevalent complication of sepsis, causes substantial burden on patients’ families as well as the society. More reliable markers are urgently required for the prevention and treatment of AKI. Pleckstrin homology-like domain, family A, member 1 (PHLDA1) was implicated in various diseases, but its involvement in sepsis-induced AKI remains to be explored. The JNK/ERK pathway has been revealed as being involved in progression of sepsis. One previous study demonstrated that PHLDA1 could activate the JNK/ERK pathway in hepatic ischemia/reperfusion injury. Nevertheless, involvement of PHLDA1 in sepsis-triggered AKI through the JNK/ERK pathway has not been probed. Methods: A cecal ligation and punctured (CLP) mice model of sepsis-induced AKI was estab-lished. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence staining were applied to evaluate the expression of PHLDA1. Concentration of blood urea nitrogen (BUN) and serum creatinine (Scr), inflammation markers, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α, as well as oxidative stress-associated proteins (catalase, malondialdehyde, superoxide dismutase, and glutathione), in the kidney tissues of mice were evaluated by enzyme-linked-immunosorbent serologic assay. Western blot analysis was applied for measuring protein expression levels. Results: The BUN and SCr levels in mice were obviously elevated in the CLP group compared to the sham group. Moreover, the expression of PHLDA1 was also elevated in the CLP group in comparison to the sham group. Down-regulation of PHLDA1 alleviated renal injury, inflam-mation, and oxidative stress in AKI model. Mechanistic study showed that PHLDA1 knockdown suppressed the activation of c-JUN N-terminal kinase/p38 and extracellular signal-regulated kinase (JNK/ERK) pathway. Conclusion: Down-regulation of PHLDA1 suppressed inflammation and oxidative stress through the modulation of JNK/ERK pathway in sepsis-induced AKI. The results could offer a novel insight into the treatment of patients with sepsis-induced AKI.