Dexamethasone inhibited angiotensin II and its receptors to reduce sepsis-induced lung and kidney injury in rats

Glucocorticoid reduces mortality in LPS-induced sepsis mouse model by inhibiting JAK1/STAT3-mediated inflammatory response and restoring tricarboxylic acid cycle

AIMS

Sepsis is characterized by a systemic inflammation disorder and multi-organ dysfunction caused by infection. Glucocorticoids (GCs), as anti-inflammatory properties drugs, are widely used for the management of patients with inflammatory diseases, including sepsis. However, the therapeutic effect and underlying mechanisms of GCs on sepsis remain incompletely understood.

MATERIALS AND METHODS

Mouse sepsis models were constructed using intraperitoneal injection of lipopolysaccharide (LPS) and treated with synthetic GC dexamethasone (DEX). Systemic inflammation and organ injury were evaluated by histological staining, immunophenotypic analysis, and detection of inflammatory cytokines. Inflammatory signaling pathways were identified by western blot (WB) and RT-qPCR. Finally, targeted metabolomics were conducted to examine metabolic changes.

KEY FINDINGS

Subcutaneous administration of DEX significantly alleviate LPS-induced acute organ injury and systemic inflammation, thereby reducing mortality in septic mice. DEX substantially reduced the amounts of intrahepatic neutrophils/macrophages, and inflammatory cytokines expressions in the livers of septic mice and in LPS-stimulated bone-marrow-derived macrophages (BMDMs). Mechanistically, DEX inhibit JAK1/STAT3 signaling pathway both in livers and BMDMs. Pharmacological inhibition of JAK1 or STAT3 via Upadacitinib or Stattic, respectively, partially mimic the anti-inflammatory function of GC, including the reduction of intrahepatic macrophages, proinflammatory cytokines production, and mortality in septic mice. Additionally, DEX could also promote the rewiring of tricarboxylic acid (TCA) cycle in the livers of septic mice.

SIGNIFICANCE

This study provides important insights into the molecular and metabolic mechanisms underlying GCs-mediated anti-inflammatory reactions.

Pharmacologic and endotoxic reprogramming of renal vasodilatory, inflammatory, and apoptotic blemishes in weaning preeclamptic rats

Preeclampsia (PE) and peripartum sepsis are two complications of pregnancy and are often associated with disturbed renal function due possibly to dysregulated renin angiotensin system. Here we evaluated hemodynamic and renal consequences of separate and combined PE and sepsis insults in weaning mothers and tested whether this interaction is influenced by prenatally-administered losartan (AT1-receptor blocker) or pioglitazone (PPARγ agonist). The PE-rises in blood pressure and proteinuria induced by gestational nitric oxide synthase inhibition (L-NAME, 50 mg/kg/day for 7 days) were attenuated after simultaneous treatment with losartan or pioglitazone. These drugs further improved glomerular and tubular structural defects and impaired vasodilatory responses evoked by adenosinergic (N-ethylcarboxamidoadenosine) or cholinergic (acetylcholine) receptor activation in perfused kidneys of weaning dams. Likewise, treatment of weaning PE dams with a single 4-h dosing of lipopolysaccharides (LPS, 5 mg/kg) weakened renal structural damage, enhanced renal vasodilations and accentuated the upregulated vasodilatory response set off by losartan or pioglitazone. Molecularly, the favorable effect of pharmacologic or endotoxic intervention was coupled with dampened tubular and glomerular expressions of inflammatory (toll-like receptor 4) and apoptotic signals (caspase-3). Our data unveil beneficial and possibly intensified conditioning effect for endotoxemia when combined with losartan or pioglitazone against preeclamptic renovascular dysfunction and inflammation.