A major ingredient of green tea rescues mice from lethal sepsis partly by inhibiting HMGB1

Background

The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-γ) and late (e.g., HMGB1) pro-inflammatory cytokines. Our recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We previously reported that green tea brewed from the leaves of the plant Camellia sinensis is effective in inhibiting endotoxin-induced HMGB1 release.

Methods and Findings

Here we demonstrate that its major component, (-)-epigallocatechin-3-gallate (EGCG), but not catechin or ethyl gallate, dose-dependently abrogated HMGB1 release in macrophage/monocyte cultures, even when given 2–6 hours post LPS stimulation. Intraperitoneal administration of EGCG protected mice against lethal endotoxemia, and rescued mice from lethal sepsis even when the first dose was given 24 hours after cecal ligation and puncture. The therapeutic effects were partly attributable to: 1) attenuation of systemic accumulation of proinflammatory mediator (e.g., HMGB1) and surrogate marker (e.g., IL-6 and KC) of lethal sepsis; and 2) suppression of HMGB1-mediated inflammatory responses by preventing clustering of exogenous HMGB1 on macrophage cell surface.

Conclusions

Taken together, these data suggest a novel mechanism by which the major green tea component, EGCG, protects against lethal endotoxemia and sepsis.     

Suppression of HMGB1 release by stearoyl lysophosphatidylcholine:an additional mechanism for its therapeutic effects in experimental sepsis

Stearoyl lysophosphatidylcholine (LPC) has recently been proven protective against lethal sepsis by stimulating neutrophils to eliminate invading pathogens through an H2O2-dependent mechanism. Here, we demonstrate that stearoyl LPC, but not caproyl LPC, significantly attenuates circulating high-mobility group box 1 (HMGB1) levels in endotoxemia and sepsis by suppressing endotoxin-induced HMGB1 release from macrophages/monocytes. Neutralizing antibodies against G2A, a potential cell surface receptor for LPC, partially abrogated stearoyl LPC-mediated suppression of HMGB1 release. Thus, stearoyl LPC confers protection against lethal experimental sepsis partly by facilitating the elimination of the invading pathogens and partly by inhibiting endotoxin-induced release of a late proinflammatory cytokine, HMGB1.     

Anti-inflammatory role of fetuin-A in injury and infection

Infection and injury are two seemingly unrelated processes that often converge on common innate inflammatory responses mediated by pathogen- or damage-associated molecular patterns (PAMPs or DAMPs). If dysregulated, an excessive inflammation manifested by the overproduction and release of proinflammatory mediators (e.g., TNF, IFN-γ, and HMGB1) may adversely lead to many pathogenic consequences. As a counter-regulatory mechanism, the liver strategically re-prioritizes the synthesis and systemic release of acute phase proteins (APP) including the fetuin-A (also termed alpha-2-HS-glycoprotein for the human homologue). Fetuin-A is divergently regulated by different proinflammatory mediators, and functions as a positive or negative APP in injury and infection. It not only facilitates anti-inflammatory actions of cationic polyamines (e.g., spermine), but also directly inhibits PAMP-induced HMGB1 release by innate immune cells. Peripheral administration of fetuin-A promotes a short-term reduction of cerebral ischemic injury, but confers a long-lasting protection against lethal endotoxemia. Furthermore, delayed administration of fetuin-A rescues mice from lethal sepsis even when the first dose is given 24 hours post the onset of disease. Collectively, these findings have reinforced an essential role for fetuin-A in counter-regulating injury- or infection-elicited inflammatory responses.     

Structural basis for the proinflammatory cytokine activity of high mobility group box 1

High mobility group box 1 (HMGB), a ubiquitous DNA-binding protein, has been implicated as a proinflammatory cytokine and late mediator of lethal endotoxemia. HMGB1 is released by activated macrophages. It amplifies and extends the inflammatory response by inducing cytokine release and mediating acute lung injury, anorexia, and the inflammatory response to tissue necrosis. The kinetics of HMGB1 release provide a wide therapeutic window for endotoxemia because extracellular levels of HMGB1 begin to increase 12 to 24 h after exposure to inflammatory stimuli. Here, we demonstrate that a DNA-binding domain of HMGB1, the B box, recapitulates the cytokine activity of full length HMGB1 and efficiently activates macrophages to release tumor necrosis factor (TNF) and other proinflammatory cytokines. Truncation of the B box revealed that the TNF-stimulating activity localizes to 20 amino acids (HMGB1 amino acids 89 to 108). Passive immunization of mice with antibodies raised against B box conferred significant protection against lethal endotoxemia or sepsis, induced by cecal perforation. These results indicate that a proinflammatory domain of HMGB1 maps to the highly conserved DNA-binding B box, making this primary sequence a suitable target in the design of therapeutics.     

Use of Animal Model of Sepsis to Evaluate Novel Herbal Therapies

Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection. It has been routinely simulated in animals by several techniques, including infusion of exogenous bacterial toxin (endotoxemia) or bacteria (bacteremia), as well as surgical perforation of the cecum by cecal ligation and puncture (CLP)^1-3. CLP allows bacteria spillage and fecal contamination of the peritoneal cavity, mimicking the human clinical disease of perforated appendicitis or diverticulitis. The severity of sepsis, as reflected by the eventual mortality rates, can be controlled surgically by varying the size of the needle used for cecal puncture². In animals, CLP induces similar, biphasic hemodynamic cardiovascular, metabolic, and immunological responses as observed during the clinical course of human sepsis³. Thus, the CLP model is considered as one of the most clinically relevant models for experimental sepsis^1-3.Various animal models have been used to elucidate the intricate mechanisms underlying the pathogenesis of experimental sepsis. The lethal consequence of sepsis is attributable partly to an excessive accumulation of early cytokines (such as TNF, IL-1 and IFN-γ)^4-6 and late proinflammatory mediators (e.g., HMGB1)⁷. Compared with early proinflammatory cytokines, late-acting mediators have a wider therapeutic window for clinical applications. For instance, delayed administration of HMGB1-neutralizing antibodies beginning 24 hours after CLP, still rescued mice from lethality^8,9, establishing HMGB1 as a late mediator of lethal sepsis. The discovery of HMGB1 as a late-acting mediator has initiated a new field of investigation for the development of sepsis therapies using Traditional Chinese Herbal Medicine. In this paper, we describe a procedure of CLP-induced sepsis, and its usage in screening herbal medicine for HMGB1-targeting therapies.     

Systemic release of high mobility group box 1 protein during severe murine influenza

Hypercytokinemia is gaining recognition as the mechanism of fatality from influenza. No work to date has addressed the role of high mobility group box 1 protein (HMGB1) in influenza, the parallel being that in other severe proinflammatory cytokine syndromes (e.g., sepsis and malaria) levels of circulating HMGB1 are elevated and may correlate with death. Using a commercially available ELISA for HMGB1, we found that HMGB1 was not increased in the plasma of influenza virus-infected mice (A/Japan/305/57) on day 7 post infection, about the time of peak mortality, and peak levels of HMGB1 in the plasma did not occur until relatively late in infection, on day 9 post infection. In keeping with the late peak of HMGB1 being unassociated with mortality, administration of ethyl pyruvate, which inhibits active secretion but not passive release of HMGB1, to influenza virus-infected mice, did not affect their survival. Further work is required to determine whether influenza virus infection induces passive release of HMGB1, and whether HMGB1 neutralization with a specific Ab would improve survival.     

IFN-gamma induces high mobility group box 1 protein release partly through a TNF-dependent mechanism

We recently discovered that a ubiquitous protein, high mobility group box 1 protein (HMGB1), is released by activated macrophages, and functions as a late mediator of lethal systemic inflammation. To elucidate mechanisms underlying the regulation of HMGB1 release, we examined the roles of other cytokines in induction of HMGB1 release in macrophage cell cultures. Macrophage migration inhibitory factor, macrophage-inflammatory protein 1beta, and IL-6 each failed to significantly induce the release of HMGB1 even at supraphysiological levels (up to 200 ng/ml). IFN-gamma, an immunoregulatory cytokine known to mediate the innate immune response, dose-dependently induced the release of HMGB1, TNF, and NO, but not other cytokines such as IL-1alpha, IL-1beta, or IL-6. Pharmacological suppression of TNF activity with neutralizing Abs, or genetic disruption of TNF expression (TNF knockout) partially (50-60%) inhibited IFN-gamma-mediated HMGB1 release. AG490, a specific inhibitor for Janus kinase 2 of the IFN-gamma signaling pathway, dose-dependently attenuated IFN-gamma-induced HMGB1 release. These data suggest that IFN-gamma plays an important role in the regulation of HMGB1 release through a TNF- and Janus kinase 2-dependent mechanism.     

A novel PINK1- and PARK2-dependent protective neuroimmune pathway in lethal sepsis

Although the PINK1-PARK2 pathway contributes to the pathogenesis of Parkinson disease, its roles in sepsis (a major challenge for critical care) were previously unknown. Here, we show that pink1^?/? and park2^?/? mice are more sensitive to polymicrobial sepsis-induced multiple organ failure and death. The decrease in the circulating level of the neurotransmitter dopamine in pink1^?/? and park2^?/? mice accelerates the release of a late sepsis mediator, HMGB1, via HIF1A-dependent anaerobic glycolysis and subsequent NLRP3-dependent inflammasome activation. Genetic depletion of Nlrp3 or Hif1a in pink1^?/? and park2^?/? mice confers protection against lethal polymicrobial sepsis. Moreover, pharmacological administration of dopamine agonist (e.g., pramipexole), HMGB1-inhibitor (e.g., neutralizing antibody or glycyrrhizin), or NLRP3-inhibitor (e.g., MCC950) reduces septic death in pink1^?/? and park2^?/? mice. The mRNA expression of HIF1A and NLRP3 is upregulated, whereas the mRNA expression of PINK1 and PARK2 is downregulated in peripheral blood mononuclear cells of patients with sepsis. Thus, an impaired PINK1-PARK2-mediated neuroimmunology pathway contributes to septic death and may represent a novel therapeutic target in critical care medicine.     

HMGB1 Mediates Anemia of Inflammation in Murine Sepsis Survivors

Patients surviving sepsis develop anemia, but the molecular mechanism is unknown. Here we observed that mice surviving polymicrobial gram-negative sepsis develop hypochromic, microcytic anemia with reticulocytosis. The bone marrow of sepsis survivors accumulates polychromatophilic and orthochromatic erythroblasts. Compensatory extramedullary erythropoiesis in the spleen is defective during terminal differentiation. Circulating tumor necrosis factor (TNF) and interleukin (IL)-6 are elevated for 5 d after the onset of sepsis, and serum high-mobility group box 1 (HMGB1) levels are increased from d 7 until at least d 28. Administration of recombinant HMGB1 to healthy mice mediates anemia with extramedullary erythropoiesis and significantly elevated reticulocyte counts. Moreover, administration of anti-HMGB1 monoclonal antibodies after sepsis significantly ameliorates the development of anemia (hematocrit 48.5 ± 9.0% versus 37.4 ± 6.1%, p < 0.01; hemoglobin 14.0 ± 1.7 versus 11.7 ± 1.2 g/dL, p < 0.01). Together, these results indicate that HMGB1 mediates anemia by interfering with erythropoiesis, suggesting a potential therapeutic strategy for anemia in sepsis.     

Splenectomy protects against sepsis lethality and reduces serum HMGB1 levels

High mobility group box 1 (HMGB1) is a critical mediator of lethal sepsis. Previously, we showed that apoptotic cells can activate macrophages to release HMGB1. During sepsis, apoptosis occurs primarily in lymphoid organs, including the spleen and thymus. Currently, it is unclear whether this accelerated lymphoid organ apoptosis contributes to systemic release of HMGB1 in sepsis. In this study, we report that splenectomy significantly reduces systemic HMGB1 release and improves survival in mice with polymicrobial sepsis. Treatment with a broad-spectrum caspase inhibitor reduces systemic lymphocyte apoptosis, suppresses circulating HMGB1 concentrations, and improves survival during polymicrobial sepsis, but fails to protect septic mice following splenectomy. These findings indicate that apoptosis in the spleen is essential to the pathogenesis of HMGB1-mediated sepsis lethality.     

Inhibitory functions of maslinic acid,a natural triterpene,on HMGB1-mediated septic responses

BackgroundMaslinic acid (MA), a natural triterpenoid from Olea europaea, prevents oxidative stress and pro-inflammatory cytokine generation. High mobility group box 1 (HMGB1) has been recognized as a late mediator of sepsis, and the inhibition of the release of HMGB1 and the recovery of vascular barrier integrity have emerged as attractive therapeutic strategies for the management of sepsis.MethodsWe tested the hypothesis that MA induces sirtuin 1 and heme oxygenase-1, which inhibit the release of HMGB1 in lipopolysaccharide (LPS)-stimulated cells, thus inhibiting HMGB1-induced hyperpermeability and increasing the survival of septic mice. MA was administered after LPS or HMGB1 challenge, and the antiseptic activity of MA was determined based on permeability, the activation of pro-inflammatory proteins, and the production of markers for tissue injury in HMGB1-activated human umbilical vein endothelial cells (HUVECs) and a cecal ligation and puncture (CLP)-induced sepsis mouse model.ResultsMA significantly reduced the release of HMGB1 in LPS-activated HUVECs and attenuated the CLP-induced release of HMGB1. Additionally, MA alleviated HMGB1-mediated vascular disruption and inhibited hyperpermeability in mice, and in vivo analysis revealed that MA reduced sepsis-related mortality and tissue injury.ConclusionTaken together, the present results suggest that MA reduced HMGB1 release and septic mortality and thus may be useful in the treatment of sepsis.     

Chlorogenic Acid Attenuates High Mobility Group Box 1 (HMGB1) and Enhances Host Defense Mechanisms in Murine Sepsis

Sepsis is a complex, multifactorial, rapidly progressive disease characterized by an overwhelming activation of the immune system and the countervailing antiinflammatory response. In the current study in murine peritoneal macrophages, chlorogenic acid suppressed endotoxin-induced high mobility group box 1 (HMGB1) release in a concentration-dependent manner. Administration of chlorogenic acid also attenuated systemic HMGB1 accumulation in vivo and prevented mortality induced by endotoxemia and polymicrobial sepsis. The mechanisms of action of chlorogenic acid included attenuation of the increase in toll-like receptor (TLR)-4 expression and suppression of sepsis-induced signaling pathways, such as c-Jun NH₂-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB, which are critical for cytokine release. The protection conferred by chlorogenic acid was achieved through modulation of cytokine and chemokine release, suppression of immune cell apoptosis and augmentation of bacterial elimination. Chlorogenic acid warrants further evaluation as a potential therapeutic agent for the treatment of sepsis and other potentially fatal systemic inflammatory disorders.     

The Heme Oxygenase-1 Inducer THI-56 Negatively Regulates iNOS Expression and HMGB1 Release in LPS-Activated RAW 264.7 Cells and CLP-Induced Septic Mice

The nuclear DNA binding protein high mobility group box 1 (HMGB1) has recently been suggested to act as a late mediator of septic shock. The effect of ((S)-6,7-dihydroxy-1-(4-hydroxynaphthylmethyl)-1,2,3,4-tetrahydroisoquinoline alkaloid, also known as THI-56, in an experimental model of sepsis was investigated. THI-56 exhibited potent anti-inflammatory properties in response to LPS in RAW 264.7 cells. In particular, THI-56 significantly inhibited the expression of inducible nitric oxide synthase (iNOS) and the release of HMGB1 in activated macrophages. THI-56 activated NE-F2-regulated factor 2 (Nrf-2)/heme oxygenase 1 (HO-1). The specific knockdown of the HO-1 gene by HO-1 siRNA significantly reversed the inhibitory effects of THI-56 on iNOS expression and HMGB1 release in LPS-stimulated macrophages. Importantly, THI-56 administration protected animals from death induced by either a lethal dose of LPS or cecal ligation and puncture (CLP). Furthermore, the ALT, AST, BUN, creatinine, and HMGB1 levels in the blood were significantly increased in CLP-induced septic mice, and the administration of THI-56 reduced these levels in a concentration-dependent and zinc protoporphyrin IX (ZnPPIX)-sensitive manner. In addition, the administration of THI-56 significantly ameliorated not only lung damage but also macrophage infiltration in the livers of CLP-induced septic mice, and these effects were also abrogated in the presence of ZnPPIX. Thus, we conclude that THI-56 significantly attenuates the proinflammatory response induced by LPS and reduces organ damage in a CLP-induced sepsis model through the upregulation of Nrf-2/HO-1.     

JH-4 reduces HMGB1-mediated septic responses and improves survival rate in septic mice

Inhibition of high mobility group box 1 (HMGB1) and restoration of endothelial integrity are emerging as attractive therapeutic strategies for the management of severe vascular inflammatory diseases. Recently, we found that JH-4, a synthesized decursin derivative, exhibited a strong anti-Hutchinson-Gilford progeria syndrome by efficiently blocking progerin-lamin A/C binding. In this study, we examined the effects of JH-4 on HMGB1-mediated septic responses and the survival rate in a mouse sepsis model. The anti-inflammatory activities of JH-4 were monitored based on its effects on lipopolysaccharide- or cecal ligation and puncture (CLP)-mediated release of HMGB1. The antiseptic activities of JH-4 were determined by measuring permeability, leukocyte adhesion, migration, and the activation of proinflammatory proteins in HMGB1-activated human umbilical vein endothelial cells and mice. JH-4 inhibited the release of HMGB1 and downregulated HMGB1-dependent inflammatory responses in human endothelial cells. JH-4 also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in mice. In addition, treatment with JH-4 reduced CLP-induced release of HMGB1, sepsis-related mortality, and pulmonary injury in vivo. Our results indicate that JH-4 is a possible therapeutic agent to treat various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.     

Persicarin is anti‐inflammatory mediator against HMGB1‐induced inflammatory responses in HUVECs and in CLP‐induced sepsis mice

High mobility group box 1 (HMGB1) protein is a crucial nuclear cytokine that mediates inflammatory responses, whereas persicarin is an active compound from Oenanthe javanica that has been widely researched for its neuroprotective and antioxidant activities. However, little is known of the effects of persicarin on HMGB1‐mediated inflammatory response. Here, we investigated this issue by monitoring the effects of persicarin on the lipopolysaccharide (LPS) and on the cecal ligation and puncture (CLP)‐mediated releases of HMGB1 and the effects of persicarin on the HMGB1‐mediated modulation of inflammatory response. Persicarin potently inhibited the release of HMGB1 and down‐regulated HMGB1‐dependent inflammatory responses in human endothelial cells, and inhibited HMGB1‐mediated hyperpermeability and leukocyte migration in mice. Furthermore, persicarin reduced CLP‐induced HMGB1 release and sepsis‐related mortality. Given these results, persicarin should be viewed as a candidate therapeutic for the treatment of severe vascular inflammatory diseases, such as, sepsis or septic shock. J. Cell. Physiol. 228: 696–703, 2013. © 2012 Wiley Periodicals, Inc.     

Modulation of TNF release by choline requires alpha7 subunit nicotinic acetylcholine receptor-mediated signaling

The alpha7 subunit-containing nicotinic acetylcholine receptor (alpha7nAChR) is an essential component in the vagus nerve-based cholinergic anti-inflammatory pathway that regulates the levels of TNF, high mobility group box 1 (HMGB1), and other cytokines during inflammation. Choline is an essential nutrient, a cell membrane constituent, a precursor in the biosynthesis of acetylcholine, and a selective natural alpha7nAChR agonist. Here, we studied the anti-inflammatory potential of choline in murine endotoxemia and sepsis, and the role of the alpha7nAChR in mediating the suppressive effect of choline on TNF release. Choline (0.1-50 mM) dose-dependently suppressed TNF release from endotoxin-activated RAW macrophage-like cells, and this effect was associated with significant inhibition of NF-kappaB activation. Choline (50 mg/kg, intraperitoneally [i.p.]) treatment prior to endotoxin administration in mice significantly reduced systemic TNF levels. In contrast to its TNF suppressive effect in wild type mice, choline (50 mg/kg, i.p.) failed to inhibit systemic TNF levels in alpha7nAChR knockout mice during endotoxemia. Choline also failed to suppress TNF release from endotoxin-activated peritoneal macrophages isolated from alpha7nAChR knockout mice. Choline treatment prior to endotoxin resulted in a significantly improved survival rate as compared with saline-treated endotoxemic controls. Choline also suppressed HMGB1 release in vitro and in vivo, and choline treatment initiated 24 h after cecal ligation and puncture (CLP)-induced polymicrobial sepsis significantly improved survival in mice. In addition, choline suppressed TNF release from endotoxin-activated human whole blood and macrophages. Collectively, these data characterize the anti-inflammatory efficacy of choline and demonstrate that the modulation of TNF release by choline requires alpha7nAChR-mediated signaling.     

Ghrelin protects against experimental sepsis by inhibiting high-mobility group box 1 release and by killing bacteria

Sepsis, a life-threatening complication of infections and the most common cause of death in intensive care units, is characterized by a hyperactive and out-of-balance network of endogenous proinflammatory cytokines. None of the current therapies are entirely effective, illustrating the need for novel therapeutic approaches. Ghrelin (GHR) is an orexigenic peptide that has emerged as a potential endogenous anti-inflammatory factor. In this study, we show that the delayed administration of GHR protects against the mortality in various models of established endotoxemia and sepsis. The therapeutic effect of GHR is mainly mediated by decreasing the secretion of the high mobility box 1 (HMGB1), a DNA-binding factor that acts as a late inflammatory factor critical for sepsis progression. Macrophages seem to be the major cell targets in the inhibition of HMGB1 secretion, in which GHR blocked its cytoplasmic translocation. Interestingly, we also report that GHR shows a potent antibacterial activity in septic mice and in vitro. Remarkably, GHR also reduces the severity of experimental arthritis and the release of HMGB1 to serum. Therefore, by regulating crucial processes of sepsis, such as the production of early and late inflammatory mediators by macrophages and the microbial load, GHR represents a feasible therapeutic agent for this disease and other inflammatory disorders.     

A small molecule binding HMGB1 inhibits caspase-11-mediated lethality in sepsis

Caspase-11, a cytosolic lipopolysaccharide (LPS) receptor, mediates lethal immune responses and coagulopathy in sepsis, a leading cause of death worldwide with limited therapeutic options. We previously showed that over-activation of caspase-11 is driven by hepatocyte-released high mobility group box 1 (HMGB1), which delivers extracellular LPS into the cytosol of host cells during sepsis. Using a phenotypic screening strategy with recombinant HMGB1 and peritoneal macrophages, we discovered that FeTPPS, a small molecule selectively inhibits HMGB1-mediated caspase-11 activation. The physical interaction between FeTPPS and HMGB1 disrupts the HMGB1-LPS binding and decreases the capacity of HMGB1 to induce lysosomal rupture, leading to the diminished cytosolic delivery of LPS. Treatment of FeTPPS significantly attenuates HMGB1- and caspase-11-mediated immune responses, organ damage, and lethality in endotoxemia and bacterial sepsis. These findings shed light on the development of HMGB1-targeting therapeutics for lethal immune disorders and might open a new avenue to treat sepsis.Subject terms: Cell death and immune response, Sepsis     

Tanshinone IIA and astragaloside IV promote the migration of mesenchymal stem cells by up-regulation of CXCR4

Mesenchymal stem cells (MSCs) have a therapeutic potential to treat cardiovascular diseases. However, a significant barrier to MSC therapy is insufficient MSC engraftment in ischemic myocardium after systemic administration. Here, we investigated the modulatory effects of tanshinone IIA and astragaloside IV on the migration of MSCs and further defined the underlying mechanisms. CXCR4 expression in MSCs was determined by using flow cytometry, real-time PCR, and western blotting. The results showed that CXCR4 expression was significantly higher in tanshinone IIA- and astragaloside IV-stimulated MSCs than that of the control. MSC migration toward stromal cell-derived factor-1α (SDF-1α) was studied using a transwell system. MSCs treated with tanshinone IIA and astragaloside IV showed stronger migration than that of the control. Moreover, this enhanced migration ability was abrogated by a CXCR4 inhibitor. In a rat acute myocardial infarction model, MSCs stimulated with tanshinone IIA and astragaloside IV were stained with Dio and injected into model rats via the tail vein. Dio-labeled cells in myocardium sections were observed by fluorescence microscopy. Tanshinone IIA- and astragaloside IV-stimulated MSCs showed enhanced capacities to home to ischemic myocardium sites. In addition, there was no significant difference in the SDF-1α expression among groups. These data suggest that tanshinone IIA and astragaloside IV regulate MSC mobilization, at least partially via modulation of the CXCR4 expression.     

Anti‐inflammatory activities of isorhamnetin‐3‐O‐galactoside against HMGB1‐induced inflammatory responses in both HUVECs and CLP‐induced septic mice

High mobility group box 1 (HMGB1) protein is a crucial nuclear cytokine that elicits severe vascular inflammatory diseases. Oenanthe javanica (water dropwort) extract has anti‐arrhythmic, neuroprotective and anti‐diabetic activity. However, isorhamnetin‐3‐O‐galactoside (I3G), an active compound from O. javanica, is not researched well for its biological activity. Here, we investigated the anti‐inflammatory activities of I3G by monitoring the effects of I3G on the lipopolysaccharide (LPS) or cecal ligation and puncture (CLP)‐mediated release of HMGB1 and HMGB1 or CLP‐mediated modulation of inflammatory responses. I3G potently inhibited the release of HMGB1 and down‐regulated HMGB1‐dependent inflammatory responses in human endothelial cells. I3G also inhibited HMGB1‐mediated hyperpermeability and leukocyte migration in mice. Further studies revealed that I3G suppressed the production of tumor necrosis factor‐α and activation of nuclear factor‐κB by HMGB1. In addition, I3G reduced CLP‐induced HMGB1 release and sepsis‐related mortality. Given these results, I3G should be viewed as a candidate therapeutic agent for the treatment of severe vascular inflammatory diseases such as sepsis or septic shock via inhibition of the HMGB1 signaling pathway. J. Cell. Biochem. 114: 336–345, 2013. © 2012 Wiley Periodicals, Inc.