Human kallistatin administration reduces organ injury and improves survival in a mouse model of polymicrobial sepsis

Abstract

SummaryKallistatin, a plasma protein, has been shown to exert multi-factorial functions including inhibition of inflammation, oxidative stress and apoptosis in animal models and cultured cells. Kallistatin levels are reduced in patients with sepsis and in lipopolysaccharide (LPS)-induced septic mice. Moreover, transgenic mice expressing kallistatin are more resistant to LPS-induced mortality. Here, we investigated the effects of human kallistatin on organ injury and survival in a mouse model of polymicrobial sepsis. In this study, mice were injected intravenously with recombinant kallistatin (KS3, 3 mg/kg; or KS10, 10 mg/kg body weight) and then rendered septic by caecal ligation and puncture 30 min later. Kallistatin administration resulted in a > 10-fold reduction of peritoneal bacterial counts, and significantly decreased serum tumour necrosis factor-a, interleukin-6 and high mobility group box-1 (HMGB1) levels. Kallistatin also inhibited HMGB1 and toll-like receptor-4 gene expression in the lung and kidney. Administration of kallistatin attenuated renal damage and decreased blood urea nitrogen and serum creatinine levels, but increased endothelial nitric oxide synthase and nitric oxide levels in the kidney. In cultured endothelial cells, human kallistatin via its heparin-binding site inhibited HMGB1-induced nuclear factor-jB activation and inflammatory gene expression. Moreover, kallistatin significantly reduced apoptosis and caspase-3 activity in the spleen. Furthermore, kallistatin treatment markedly improved the survival of septic mice by 23% (KS3) and 41% (KS10). These results indicate that kallistatin is a unique protecting agent in sepsis-induced organ damage and mortality by inhibiting inflammation and apoptosis, as well as enhancing bacterial clearance in a mouse model of polymicrobial sepsis.

Kallistatin in Sepsis: Protective Actions and Potential Therapeutic Applications

“…Moreover, kallistatin via its heparin-binding site antagonizes TNF-α-induced oxidative stress, NF-κB activation and inlammatory gene expression in vitro [20]. Likewise, kallistatin blocks HMGB1-mediated synthesis of inlammatory genes in endothelial cells [29]. Moreover, kallistatin ameliorates inlammation by blocking VEGF-induced endothelial cell permeability [16,20].…”

“…Kallistatin's active site is crucial for: (1) complex formation with tissue kallikrein and inhibiting tissue kallikrein activity and bioavailability [13,27]; (2) increasing eNOS and SIRT1 expression and activation, leading to elevated NO formation [28]; (3) stimulating SOCS3 expression [48]; and (4) interacting with a tyrosine kinase [28,48]. Kallistatin via its heparin-binding domain interacts with cell surface heparan sulfate proteoglycans, thereby antagonizing the following biological efects: (1) VEGF-mediated angiogenesis and vascular permeability [16,20]; (2) TNF-α-induced NF-κB activation, inlammation, oxidative stress, and apoptosis [20]; (3) HMGB1-induced inlammatory gene expression and oxidative stress [29]; (4) TGF-β-induced endothelial-mesenchymal transition (EndMT), and epithelialmesenchymal transition (EMT) [28]; (5) Wnt-mediated cancer cell proliferation, migration, invasion, and autophagy [42,44]; and (6) EGF-induced cancer cell migration and invasion (unpublished results). Thus, kallistatin, with its multifactorial activities, regulates a wide spectrum of biological processes, such as angiogenesis, inlammation, oxidative stress, apoptosis, ibrosis, and cancer development.…”

“…In contrast to α1-antitrypsin, kallistatin is a negative acute-phase protein, as kallistatin expression in rat liver is rapidly downregulated within 24 h after lipopolysaccharide (LPS)-induced endotoxemia [31]. Kallistatin levels are depleted in animal models with hypertension, diabetes, cardiovascular, and renal damage [11,18,[29][30][31]. Circulatory kallistatin levels are markedly reduced in patients with septic syndrome, liver disease, diabetic retinopathy, inlammatory bowel disease, and severe pneumonia [33,34,[36][37][38].…”

“…A human kallistatin gene polymorphism is correlated with a decreased risk of developing acute kidney injury in patients with septic shock [64]. Kallistatin treatment exerts beneicial efects in Gram-negative and Gram-positive bacteremia, as well as "mixed" polymicrobial infection [29,35,48,65]. Transgenic mice expressing kallistatin are highly resistant to mortality induced by LPS [66].…”

“…The active site of kallistatin is necessary for complex formation with tissue kallikrein and thus inhibition of tissue kallikrein activity and bioavailability [13,27]. Kallistatin's heparinbinding domain, however, is essential for antagonizing signaling pathways mediated by vascular endothelial growth factor (VEGF), TNF-α, HMGB 1 , and transforming growth factor (TGF)-β [16,20,28,29]. Kallistatin levels are markedly reduced in hypertensive or normotensive rodents with cardiac and renal injury or streptozotocin-induced diabetes [11,18,[30][31][32].…”