Resveratrol Downregulates Biomarkers of Sepsis Via Inhibition of Proteasome's Proteases

Abstract

Lipopolysaccharide (LPS) is the main agonist of gram-negative bacteria and initiates inflammation. We recently reported that plasmas from sepsis patients revealed increased levels of following group of biomarkers; VCAM-1, ICAM1, CRP, resistin, and proteasome LMP subunits. Our objective here was to compare effects of resveratrol (shown to be a nonspecific proteasome inhibitor by us) and a known LMP7 inhibitor (ONX-0914, specific inhibitor) on proteasome's activities, as well as on inflammatory markers mentioned above in human blood monocytes. Using fluorescence-based assays on blood monocytes purified proteasomes, resveratrol (0-100 μM) inhibited all three protease activities, predominantly LMP7. Similarly, resveratrol inhibited all three protease activities using cell-based luminescence assay. In contrast, ONX-0914 was more selective and potent for LMP7 activity. Resveratrol and ONX-0914, both significantly inhibited expression of LPS-induced biomarkers mentioned above in CD14 monocytes. Moreover, resveratrol itself, as well as in combination with LPS, accumulated pIκBα in CD14 monocytes. Collectively, our data suggest that resveratrol is a less potent inhibitor of all three; CT-like (predominantly LMP7), T-like and PA protease activities and is less toxic to human monocytes than ONX-0914 (a selector inhibitor of only LMP7) as observed by an autophagy detection kit. Also, resveratrol reduces LPS-induced inflammatory cytokine expression by decreasing the translocation of NF-κB due to an increase in inhibitor pIκBα. Therefore, resveratrol can be used to curb inflammation in diseased states like sepsis and other disorders.

Immunoproteasome Inhibition Selectively Kills Human CD14+ Monocytes and as a Result Dampens IL-23 Secretion

“…*p , 0.05, **p , 0.01. the pan IP inhibitor LU-005i did not increase cell death of CD11c + , CD11b + , NK1.1 + , CD19 + , CD4 + , and CD8 + after 24 h (27). Silswal et al (54) showed that treatment of THP-1 cells, a human monocytic leukemia cell line, with 250 nM ONX 0914 resulted in autophagy and vacuole accumulation. In addition, no increase in poly(ADP-ribose) polymerase cleavage was observed in ONX 0914-treated TCR-activated mouse or human CD4 cells (53).…”

Challenge to the Intestinal Mucosa During Sepsis

“…Consequently, PAMPs induce a “cytokine storm” of pro-inflammatory mediators, which drive the local intestinal and systemic inflammation (32). The released mediators can lead to an upregulation of endothelial adhesion molecules (e.g., ICAM, VCAM, E-, and P-selectin), resulting in increased recruitment of neutrophils and monocytes and in turn to increased levels of pro-inflammatory cytokines and ROS (34, 35). These cellular responses aggravate vasodilatation and induce a high level of capillary leakage with the development of interstitial edema.…”

Systematic review and meta-analysis of the protective effect of resveratrol on multiple organ injury induced by sepsis in animal models

“…Cerqueira et al (54) reported that resveratrol significantly reduced the production of ROS, intercellular adhesion molecule 1 (ICAM-1), human β-defensin-2 and cell surface Fas receptor, inhibited caspase-3 and -7 activation, and upregulated glutathione peroxidase expression in a Pseudomonas aeruginosa-induced A549 cell injury model. Silswal et al (55) reported that resveratrol inhibited expression of inflammatory factors in LPS-induced human cluster of differentiation (CD)14 + monocytes, including of vascular cell adhesion molecule 1, ICAM1, C-reactive protein and resistin, and activity of proteasome subunit low-molecular-weight protein 7. Other studies have shown that resveratrol inhibited the phosphorylation of NF-κB-p65 and the expression of inflammatory factors in human THP-1 cells following LPS induction (37,56).…”