Barrier protective effects of rosmarinic acid on HMGB1‐induced inflammatory responses in vitro and in vivo

Abstract

High mobility group box 1 (HMGB1) protein is a crucial cytokine that mediates response to infection, injury, and inflammation. Rosmarinic acid (RA) is an important component of the leaves of Perilla frutescens and has neuroprotective, anti-microbial, anti-oxidant, and anti-cancer effects but little is known of its effects on HMGB1-mediated inflammatory response. Here, we investigated this issue by monitoring the effects of RA on the lipopolysaccharide (LPS) or cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated modulation of inflammatory responses. RA potently inhibited the release of HMGB1 and down-regulated HMGB1-dependent inflammatory responses in human endothelial cells. RA also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in mice. Furthermore, RA reduced CLP-induced HMGB1 release and sepsis-related mortality. Given these results, RA should be viewed as a candidate therapeutic agent for the treatment of various inflammatory diseases via inhibition of the HMGB1 signaling pathway.

HMGB1 in health and disease

“…In addition, we and others have demonstrated that administration of anti-HMGB1 antibodies (Qin et al, 2006; Valdes-Ferrer et al, 2013; Wang et al, 1999; Yang et al, 2004a), inhibitors (e.g. ethyl pyruvate (Ulloa et al, 2002), nicotine (Wang et al, 2004a), stearoyl lysophosphatidylcholine (Chen et al, 2005), quercetin (Tang et al, 2009), chloroquine (Yang et al, 2013d), spermine (Zhu et al, 2009) and Chinese herbal extracts such as Angelica sinensis (Wang et al, 2006) and Salvia miltiorrhiza (Li et al, 2007b)) or endogenous hormones (e.g., insulin (Hagiwara et al, 2008b), vasoactive intestinal peptide (Chorny and Delgado, 2008), and ghrelin (Chorny et al, 2008; Wu et al, 2009)) protect mice against lethal endotoxemia and rescue mice from cecal ligation and puncture-induced lethal experimental sepsis even when the first doses are given 24 hours after the onset of sepsis. Taken together, these results suggest that HMGB1 is released in a delayed manner and functions as a late mediator of lethal sepsis and thus as a therapeutic target with a wider time window for clinical intervention (Andersson and Tracey, 2003, 2011; Huang et al, 2010; Wang et al, 2009a; Wang et al, 2004b; Wang et al, 2008a; Waterer, 2007).…”

The first cyclomegastigmane rhododendroside A from Rhododendron brachycarpum alleviates HMGB1-induced sepsis

“…Compounds 1–5 , showing vascular barrier protective activity in an HMGB1-mediated permeability test (See Biological Assay Details in Supplementary data 2), were further evaluated for their potential to hamper HMGB1-mediated vascular disruption as cause of severe septic diseases [9,10,20]. To evaluate the actin cytoskeletal arrangement activity of 1–5 , human umbilical vein endothelial cells (HUVECs) were treated with 10 μM of each compound employing immunofluorescence staining of HUVEC monolayers with the F-actin labeled fluorescein phalloidin (Fig.…”

“…4C). Phosphorylation of p38 MAPK (mitogen-activated protein kinase)was also evaluated employing enzyme-linked immunosorbent assay (ELISA) based on studies that HMGB1 induces pro-inflammatory response by promoting phosphorylation of p38 [9,10]. The treatment of HUVECs with HMGB1 significantly enhanced phosphorylation of p38 and this up-regulation was attenuated upon the pretreatment with 1 , 2 , and 5 , indicating that they averted HMGB1-induced pro-inflammatory reactions and consequently maintaining vascular barrier integrity (Fig.…”

“…The only FDA-approved antiseptic drug, drotrecogin alfa (Xigris®), was withdrawn from the market due to its questionable efficacy [8], thus stressing the necessity for the search of potent antiseptic prototypes with novel modes of action (MOA). Among the therapeutic strategies targeting the mitigation of sepsis [7], enhancement of the integrity of endothelial cells (ECs) has emerged as a sensible MOA of an antiseptic drug [9,10]. Disruption of the integrity of ECs facilitates leucocytes to access inflamed tissue and hence initiating such vascular inflammatory manifestations [9,10].…”

“…Among the therapeutic strategies targeting the mitigation of sepsis [7], enhancement of the integrity of endothelial cells (ECs) has emerged as a sensible MOA of an antiseptic drug [9,10]. Disruption of the integrity of ECs facilitates leucocytes to access inflamed tissue and hence initiating such vascular inflammatory manifestations [9,10]. In this regard, high mobility group box 1 (HMGB1) protein could be a specific target for the discovery of novel antiseptic agents capable of achieving vascular barrier augmentation because of the role of the protein in disturbing the barrier integrity of ECs, and ultimately inducing severe sepsis and related manifestations [9–11].…”