JMJD3 is involved in neutrophil membrane proteinase 3 overexpression during the hyperinflammatory response in early sepsis

Abstract

Excessive production of pro-inflammatory cytokines in early sepsis causes high early mortality rates. Membrane proteinase 3 (mPR3) expression on neutrophils plays a critical role in pro-inflammatory cytokine production. However, the mechanism underlying mPR3 overexpression in early sepsis is unknown. Here, we explored mPR3 expression in early sepsis and its regulatory mechanism. Thirty-two patients with sepsis and 20 healthy controls were prospectively enrolled. On day 1 after the onset of sepsis, mPR3 and jumonji domain-containing protein D3 (JMJD3) expression levels were measured in peripheral blood neutrophils. Lipopolysaccharide (LPS) was employed to induce JMJD3 expression in vitro, and GSK-J4 was used to inhibit JMJD3. Neutrophils were divided into four groups, control, LPS, LPS + GSK-J4, and GSK-J4, and cultured with THP-1 cells respectively. Plasma and culture supernatant cytokine levels were measured by enzyme-linked immunosorbent assays. Neutrophil mPR3 levels were significantly higher in patients with early sepsis than in healthy controls. Plasma cytokine (IL-1β and TNF-α) levels were increased in patients with sepsis exhibiting high mPR3 expression. Additionally, JMJD3 expression levels in neutrophils were increased in early sepsis. In vitro, both mPR3 on neutrophils and IL-1β in culture supernatants increased in response to LPS stimulation. Neutrophil mPR3 expression and IL-1β levels were significantly reduced by GSK-J4 in cells treated with LPS. IL-1β level was significantly higher in LPS-stimulated co-culture supernatants than in the corresponding individual cultured cells. Thus, our results suggest that JMJD3 contributes to the high expression of neutrophil mPR3, which promotes the production of proinflammatory IL-1β in early sepsis.