Hai-Yan Sun

Psoriasis is a chronic inflammatory skin disease, often accompanied by increased infiltration of immune cells, especially neutrophils. However, the detailed mechanism of the neutrophil function in psoriasis progression remains unclear. Here, we found that both Src homology‐2 domain‐containing protein tyrosine phosphatase‐2 (SHP2) and neutrophils were highly correlated to developing psoriasis by single‐cell ribonucleic acid (RNA) sequencing and experiment verification. The deficiency of SHP2 in neutrophils significantly alleviated psoriasis‐like phenotype in an imiquimod‐induced murine model. Interestingly, high levels of neutrophil extracellular traps (NETs) were produced in the inflamed lesions of psoriatic patients. In addition, imiquimod‐induced psoriasis‐like symptoms were remarkably ameliorated in peptidyl arginine deiminase 4 (PAD4) knockout mice, which cannot form NETs. Mechanistically, RNA‐seq analysis revealed that SHP2 promoted the formation of NETs in neutrophils via the ERK5 pathway. Functionally, this mechanism resulted in the infiltration of pro‐inflammatory cytokines such as TNF‐α, IL‐1β, IL‐6, IL‐17A, and CXCL‐15, which enhances the inflammatory response in skin lesions and reinforces the cross‐talk between neutrophils and keratinocytes, ultimately aggravating psoriasis. Our findings uncover a role for SHP2 in NET release and subsequent cell death known as NETosis in the progression of psoriasis and suggest that SHP2 may be a promising therapeutic target for psoriasis.

Green tea polyphenols (GTPs) have been shown to exhibit diverse beneficial effects against a variety of diseases. Acetaminophen (APAP) overdose is one of the most frequent causes of drug‐induced liver injury. In the current study, we aimed to investigate the protective effect of GTP on APAP‐induced liver injury in mice and the underlying mechanisms involved. Male C57BL/6J mice were treated orally with different doses of GTP (37.5, 75, or 150 mg/kg) 4 h after APAP overdose (400 mg/kg) and continuously given every 8 h until sacrificed at 4, 12, 20, and 48 h after the first treatment of GTP. Survival rate and histological and biochemical assessments were performed to evaluate the APAP‐induced liver injury. Protein expression of multiple drug metabolizing enzymes and transporters was measured to demonstrate the possible mechanisms involved. Our results revealed that administration of different doses of GTP significantly alleviated APAP‐induced liver injury by improving the survival rate, hepatocellular necrosis, and ALT/AST/GSH levels after APAP overdose (400 mg/kg). The protein expression of APAP‐induced drug transporters and metabolizing enzymes was mostly induced by GTP treatment, which was followed by reduction in drug transporters at the later time points. The current study collectively demonstrated that GTP protects against APAP‐induced liver injury, possibly through regulating drug metabolizing enzymes and transporters after APAP overdose.