Synergistic effect of collagen and CXCL12 in the low doses on human platelet activation

CXCL12, also known as stromal cell-derived factor-1, is a chemokine classified into CXC families, which exerts its function by binding to specific receptors called CXCR4 and CXCR7. Human platelets express CXCR4 and CXCR7 on the plasma membrane. It has been reported that CXCL12 potentiates to induce platelet aggregation in cooperation with agonists including collagen. However, the precise roles and mechanisms of CXCL12 in human platelet activation are not fully elucidated. In the present study, we investigated the effect of simultaneous stimulation with low doses of collagen and CXCL12 on the activation of human platelets. The simultaneous stimulation with collagen and CXCL12 induced the secretion of platelet-derived growth factor (PDGF)-AB and the release of soluble CD40 ligand (sCD40L) from human platelets in addition to their aggregation, despite the fact that the simultaneous stimulation with thrombin receptor-activating peptide (TRAP) or adenosine diphosphate (ADP), and CXCL12 had little effects on the platelet aggregation. The agonist of Glycoprotein (GP) Ⅵ convulxin and CXCL12 also induced platelet aggregation synergistically. The monoclonal antibody against CXCR4 but not CXCR7 suppressed the platelet aggregation induced by simultaneous stimulation with collagen and CXCL12. The phosphorylation of p38 mitogen-activated protein kinase (MAPK), but not p44/p42 MAPK, was induced by the simultaneous stimulation. In addition, the simultaneous stimulation with collagen and CXCL12 induced the phosphorylation of HSP27 and the subsequent release of phosphorylated-HSP27 from human platelets. SB203580, a specific inhibitor of p38 MAPK, attenuated the platelet aggregation, the phosphorylation of p38 MAPK and HSP27, the PDGF-AB secretion, the sCD40L release and the phosphorylated-HSP27 release induced by the simultaneous stimulation with collagen and CXCL12. These results strongly suggest that collagen and CXCL12 in low doses synergistically act to induce PDGF-AB secretion, sCD40L release and phosphorylated-HSP27 release from activated human platelets via p38 MAPK activation.

CD4+ T cells and TGFβ1/MAPK signal pathway involved in the valvular hyperblastosis and fibrosis in patients with rheumatic heart disease

The aim of this study was to investigate the roles of CD4⁺ T cells and transforming growth factor beta (TGFβ1) in the pathological process of valvular hyperblastosis and fibrosis of patients with rheumatic heart disease (RHD). A total of 151 patients were enrolled, among whom, 78 patients were with RHD, and 73 were age and gender matched RHD negative patients. Blood samples and valve specimens were collected for analysis. Pathological changes and collagen fibers contents of valves were analyzed using HE and Masson staining. Percentage of peripheral blood CD4⁺ T cells was tested through flow cytometry. TGFβ1 level in serum were identified by ELISA. CD4⁺ T cells infiltration and expression of TGFβ1, p-p38, p-JNK, p-ERK in valves were detected by immunohistochemistry. The mRNA and protein levels of p38, JNK, ERK, TGFβ1, I-collagen and α-SMA were detected by qRT-PCR and western blotting, respectively. The heart valve tissues of RHD patients showed higher degrees of fibrosis, calcification and lymphocytes infiltration, which were mainly CD4⁺ T cells. In addition, compared with control group, RHD patients had more total CD4⁺ T cells in peripheral blood and valve tissues. Expression of TGFβ1, phosphorylation of JNK and p38, and synthesis of I-collagen in valve tissues of RHD patients were also significantly increased. Furthermore, we found a strong positive correlation between TGFβ1 expression and phosphorylation of JNK and p38. CD4⁺ T cells, and fibrogenic cytokine TGFβ1, which activate the intracellular MAPK signaling pathway may participate in the fibrosis of heart valve in RHD patients.

Circulating fibrocytes are involved in inflammation and leukocyte trafficking in neonates with necrotizing enterocolitis

Fibrocytes, ahematopoietic stem cell source of fibroblasts/myofibroblasts, were previously implicated to infiltrate into the intestinal and enhance inflammation.The aims of the present study were to elucidate the role of fibrocytes in necrotizing enterocolitis (NEC) pathogenesis and to explore the mechanisms by which fibrocytes contributed to the inflammatory responses.We investigated circulating and intestinal local fibrocytes from 32 patients with NEC, 8 patients with noninflammatory conditions of the gastrointestinal tract and 12 normal subjects.Significantly higher numbers of circulating fibrocytes were found in the peripheral blood from NEC patients than the controls (P < .01). Numerous fibrocytes were found infiltrating the NEC intestinal mucous membranes. The percentage of fibrocytes to total leukocytes in the NEC inflammatory lesions was significantly increased compared with the percentage in the noninflammatory gastrointestinal tract. The fibrocyte attractant chemokine C-X-C motif chemokine ligand 12 (CXCL12) was significantly increased in the plasma and was detectable in 80% of the peritoneal lavage fluid from NEC patients but not the controls. Furthermore, chemokine expression was increased in fibrocytes infiltrating and trafficking to leukocyte sites. In culture, lipopolysaccharide (LPS) induced a significant increase in the expression of the Toll-like receptor (TLR4) signal, with the upregulation of p38 in both the isolated fibrocytes and macrophages. Similarly, interleukin (IL)-1β induced increased the upregulation of the IL-6, tumor necrosis factor (TNF)-α, and intercellular cell adhesion molecule-1 mRNAs but downregulated ColI in fibrocytes isolated from NEC patients compared with the controls.These findings indicate that circulating fibrocytes are increased in NEC patients and may be recruited to the inflammatory intestinal track, most likely through the CXCR4/CXCL12 axis. These cells may contribute to intestinal inflammation through TLR4 signaling by producing the TNF-α and IL-6 cytokines.

[Effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury in rats with hyperlipidemia]

OBJECTIVE

To investigate the effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury of rats with hyperlipidemia.

METHOD

Fifty SD rats were randomly divided into five groups: the normal control group (NG), the model group (MG), the antrodia cinnamomea groups of low, middle and high doses (AC-LG, AC-MG, AC-HG, 250, 500, 1 000 mg x kg(-1)). The rats were fed with high-fat diets to establish the hyperlipidemia model. After the drug administration for 10 weeks, their serum lipid, SOD, MDA and ox-LDL, LOX-1, P38 MAPK and NF-kappaB mRNA and protein expression were respectively determined, and the aortal endothelial injury was observed under electron microscope.

RESULT

In the model group, the contents of TC, TG and LDL-C significant increased (P < 0.01), whereas the content of HDL-C significant decreased (P < 0.01). Compared with the model group, both the AC-M group and the AC-H group showed reduction in endothelial injury and significant decrease in the content of TC, TG and LDL-C (P < 0.05 or P < 0.01). The content of HDL-C increased, but with no significant difference. SOD activity in serum remarkably increased (P < 0.05 or P < 0.01), MDA and ox-LDL levels dramatically decreased (P < 0.05 or P < 0.01).

CONCLUSION

A. cinnamomea can alleviate endothelial lipid injury by inhibiting the expressions of LOX-1, P38MAPK and NF-kappaB in aorta and better protect aortal endothelial cells from oxidative lipid injury.

[Effect of hydrogen inhalation on p38 MAPK activation in rats with lipopolysaccharide- induced acute lung injury]

OBJECTIVE

To investigate the effect of hydrogen inhalation on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the underlying molecular mechanisms.

METHODS

Thirty-two male SD rats were randomly divided into 4 groups (n=8), namely the normal saline group (SA), saline with 2% hydrogen gas inhalation group (SH group), ALI group, and ALI with hydrogen inhalation group (LH group). In the two ALI groups, ALI was induced by intraperitoneal injection of 15 mg/kg LPS. Treatments with inhalation of 2% hydrogen gas for 6 h was administered after the injection of LPS or saline. The concentrations of tumor necrosis factor-α (TNF-α) in the lung tissue and serum were examined with ELISA. The expression of p38 MAPK in the lung tissue was detected by Western blotting..

RESULTS

Hydrogen inhalation decreased the expression of p-p38 MAPK in the lung tissue, and significantly reduced TNF-α content in the lung tissue and serum of rats with ALI.

CONCLUSION

Hydrogen inhalation can decrease the expression of TNF-α in the lung tissue and serum, and this effect may be related with reduced p38 MAPK expression and inhibition of p38 MAPK activation.

High MAPK p38 activity and low level of IL-10 in intermittent claudication as opposed to stable angina

AIM

The aim of the present pilot study was to relate the activity of MAPK p38 with the levels of pro- and anti-inflammatory cytokines in a small cohort of patients with either stable angina (N=5) or intermittent claudication (N=5) compared to healthy controls (N=10).

METHODS

The activity of MAPK p38 was determined in peripheral blood mononuclear cells, isolated from whole blood by western blot using phospho-specific anti-MAPK p38 antibodies. Cytokine levels of 11 pro- and anti-inflammatory cytokines were determined from the serum using flow cytometry.

RESULTS

We found a significant elevation of the MAPK p38 activity in the intermittent claudication group (P=0.0027) compared with the healthy control group whereas the stable angina group showed similar MAPK p38 activity as the healthy control group. The IL-10 level in serum found in the stable angina group was significantly higher compared with both the healthy control group (P=0.0116) and the intermittent claudication group (P=0.0317).

CONCLUSION

Our results imply that there is a casual relationship between increased levels of the anti-inflammatory cytokines IL-10 and IL-4 and the activity of the MAPK p38. Possibly has IL-10 a protective role that down-regulates the activity of MAPK p38 and thereby further inflammatory processes in stable angina patients.

Oxymatrine attenuates intestinal ischemia/reperfusion injury in rats

PURPOSE

Intestinal ischemia/reperfusion (I/R) is a common and serious clinical condition. The anti-inflammatory and anti-apoptotic properties of oxymatrine, the extract from a traditional Chinese herb, Sophora flavescens Ait, have been shown to protect the liver from I/R injury and attenuate colitis. The objective of this study was to investigate if oxymatrine could attenuate intestinal I/R injury induced in rats.

METHODS

The experimental design consisted of three groups of 24 Wistar rats each: a sham-operation group (control group), a group subjected to intestinal I/R and then given saline (saline group), and a group subjected to intestinal I/R and then given oxymatrine (oxymatrine group). Intestinal I/R was induced by occluding the superior mesenteric artery for 45 min. Six rats from each group were killed at selected time points, and blood and intestinal samples were collected.

RESULTS

Morphological alteration, reduction of gamma-glutamyl transpeptidase (gamma-GGT) activity, and increased cell apoptosis confirmed intestinal I/R injury. The oxymatrine group had a significantly lower histological score and apoptosis index than the saline group, demonstrating that the preadministration of oxymatrine attenuated gut damage. Moreover, oxymatrine inhibited the production of lipid peroxides (LPO), decreased the serum levels of tumor necrosis factor (TNF)-alpha, and downregulated expression of phosphorylated p38 mitogen-activated protein kinase, Fas, and FasL, which had been elevated by I/R.

CONCLUSIONS

These results provide further evidence of the anti-inflammatory and anti-apoptotic activities of oxymatrine, which may become a potent drug for protecting the intestines against I/R injury.

Therapeutic effects and anti-inflammatory mechanisms of heparin on acute lung injury in rabbits

OBJECTIVES

The objectives were to investigate the potential beneficial effects and molecular mechanisms of heparin and low-molecular-weight heparin (LMWH) on acute lung injury (ALI).

METHODS

Forty-eight rabbits were randomized into four groups: normal control group (Group A), lipopolysaccharide (LPS) group (Group B), LPS + heparin group (Group C), and LPS + LMWH group (Group D). The rabbit ALI model was established by intravenous (IV) injection with LPS. Alveolar-arterial O2 difference (P(A-a)O2), serum tumor necrosis factor alpha (TNF-alpha), circulating p38 mitogen-activated protein kinase (p38 MAPK) levels, lung nuclear factor (NF)-kappaB levels, and lung dry/wet (D/W) ratio were measured, and the lung injury scores were calculated.

RESULTS

Lipopolysaccharide caused significant increases in P(A-a)O2, serum TNF-alpha, expression of p38 MAPK in polymorphonuclear neutrophils (PMNs), the lung injury scores, and nuclear factor-kappaB (NF-kappaB) activity in the lung tissue and caused a decrease in lung D/W ratio. A positive linear correlation was found between p38 MAPK and TNF-alpha at 1, 2, 4, and 6 hours (r = 0.68, 0.92, 0.93, and 0.93, respectively) and between NF-kappaB and p38 MAPK and TNF-alpha at 6 hours (r = 0.94 and 0.83, respectively). IV heparin or LMWH given after LPS treatment attenuated these changes in inflammatory response, oxygenation, p38 MAPK expression, and NF-kappaB activation.

CONCLUSIONS

The anti-inflammatory mechanisms of heparin in ALI may be inhibiting p38 MAPK and NF-kappaB activities, and then TNF-alpha overexpression, thus alleviating the inflammatory reaction.

Aberrant activation profile of cytokines and mitogen-activated protein kinases in type 2 diabetic patients with nephropathy

Cytokine-induced inflammation is involved in the pathogenesis of type 2 diabetes mellitus (DM). We investigated plasma concentrations and ex vivo production of cytokines and chemokines, and intracellular signalling molecules, mitogen-activated protein kinases (MAPK) in T helper (Th) cells and monocytes in 94 type 2 diabetic patients with or without nephropathy and 20 healthy controls. Plasma concentrations of inflammatory cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-18 and chemokine CCL2 in patients with diabetic nephropathy (DN) were significantly higher than control subjects, while IL-10, CXCL8, CXCL9, CXCL10 and adiponectin concentrations of DN were significantly higher than patients without diabetic nephropathy (NDN) and control subjects (all P < 0.05). Plasma concentrations of TNF-alpha, IL-6, IL-10, IL-18, CCL2, CXCL8, CXCL9, CXCL10 and adiponectin exhibited significant positive correlation with urine albumin : creatinine ratio in DN patients. The percentage increases of ex vivo production of IL-6, CXCL8, CXCL10, CCL2 and CCL5 upon TNF-alpha activation were significantly higher in both NDN and DN patients than controls (all P < 0.05). The percentage increases in IL-18-induced phosphorylation of extracellular signal-regulated kinase (ERK) in Th cells of NDN and DN were significantly higher than controls (P < 0.05), while the percentage increase in TNF-alpha-induced phosphorylation of p38 MAPK in monocytes and IL-18-induced phosphorylation of p38 MAPK in Th cells and monocytes were significantly higher in NDN patients than controls. These results confirmed that the aberrant production of inflammatory cytokines and chemokines and differential activation of MAPK in different leucocytes are the underlying immunopathological mechanisms of type 2 DM patients with DN.

Propionate induces pH(i) changes through calcium flux, ERK1/2, p38, and PKC in bovine neutrophils

Propionate is a short-chain fatty acid produced under normal physiological conditions in the rumen of cattle. It is also involved in the inflammatory process and neutrophil function via calcium release, reactive oxygen species and intracellular pH (pH(i)) changes. This study examined the effect of propionate on the pH(i) of bovine neutrophils; specifically if pH(i) changes are controlled by calcium flux, and the mitogen-activated protein kinase (MAPK) pathway. Propionate caused rapid intracellular acidification and sustained alkalinization in bovine neutrophils loaded with 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM), a fluorescent indicator of pH(i). The acidification phase seems to be controlled by intracellular calcium release and p38 MAPK pathway. The pH recovery phenomenon was mediated by an amiloride-sensitive Na+/H+ exchanger and H+ channel, and was inhibited by UO126 (an ERK1/2 MAPK phosphorylation inhibitor), Gö6850 (a PKC inhibitor) and calcium chelating. Ionomycin, a calcium ionophore, induced intracellular acidification and sustained alkalinization. The intracellular acidification was strongly inhibited by BAPTA-AM (an intracellular calcium chelator) and SB203580 (a p38 MAPK inhibitor). In addition, the intracellular alkalinization was reduced by EGTA (a calcium chelator), UO126, LY294002 (a PI3K inhibitor) and Gö6850. Propionate did not increase superoxide production, however it reduced the superoxide production induced by platelet-activating factor (PAF), and increased the release of superoxide induced by ionomycin. Our results suggest that propionate-induced intracellular acidification is mediated by intracellular calcium release and p38 MAPK activation, and that pH recovery is controlled via ERK1/2 MAPK, PKC and calcium entry in bovine neutrophils.

Rapid flow cytometric measurement of cytokine-induced phosphorylation pathways [CIPP] in human peripheral blood leukocytes

Current strategies designed to assess cells in the peripheral blood are limited to evaluation of phenotype or delayed measurement [>6 h] of function, usually quantifying cytokine production, cytolytic activity, or response to antigens. We reasoned that measurable abnormalities in signaling pathways could reflect pathological environs that cells experience in the setting of inflammatory states/cancer and could be represented in the peripheral blood. Two major pathways regulating the immune response are the JAK/STAT and MAPK/ERK pathways. These pathways are initiated by ligand-receptor binding and are rapidly propagated by subsequent protein phosphorylation cascades. We evaluated the brief application of cytokines in vitro to interrogate the early phosphorylation events of these signaling pathways in normal peripheral blood mononuclear cells (PBMC). Individual cytokine doses and time intervals of treatment were assessed to identify conditions useful in a clinical laboratory and as an initial goal to induce maximal phosphorylation. Surprisingly, all of the STAT proteins assessed and ERK1/2 are maximally phosphorylated within 15 min in human PBMC simply following addition of cytokines without preactivation of the cells. At 2 h, cells typically return to their basal phosphorylation states. For most of the cytokines tested, increased phosphorylation directly correlated with increased concentrations of the individual cytokines. These strategies will enable robust development of simple blood analyses to identify normal levels as well as impairments in STAT and MAPK/ERK signaling pathways associated with various human disease states including acute and chronic inflammatory conditions throughout clinical immunology.

Neuroendocrine profiling of humans receiving cardiac allografts

BACKGROUND

Several studies have investigated changes in circulating hormones and markers of cardiac status after heart transplantation in humans. As a result, plasma levels of various hormones and autocoids have been associated with cardiac allograft rejection status. However, no clear associations can be defined given the highly contradictory nature of the available literature.

METHODS

In this study of 69 consecutive heart transplant patients followed for >2 years we examine the relationship between neurohumors potentially related to allograft rejection and endomyocardial biopsy grade of rejection (according to the ISHLT) and hemodynamic status. Markers assessed include brain natriuretic peptide (BNP), amino-terminal pro-BNP (N-BNP), atrial natriuretic factor (ANF), adrenomedullin, interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, troponin C and C-reactive protein.

RESULTS

The highest plasma levels for most neurohumors were found shortly after surgery and showed a trend towards normalization with time. BNP and N-BNP were the only significantly elevated plasma analytes for patients with Grade 3 rejection as compared with other ISHLT grades. ANF plasma levels correlated with BNP and N-BNP in Grades 0 to 2, but not in Grade 3, suggesting that in this rejection grade the usual coordinated changes observed in BNP and ANF secretion no longer exist. Cardiac filling pressures were correlated with plasma BNP, N-BNP and ANF levels only for Grades 0 and 1.

CONCLUSIONS

The timing of blood sampling after transplantation influences the level of the neurohumors measured, which may help explain the conflicting literature reports on the association between neurohumor levels and rejection grade. The significant increase in circulating levels of BNP and N-BNP observed in most cases of Grade 3 rejection occurred with no apparent relationship to post-transplantation time, which suggests a specific influence of acute rejection on BNP gene expression.

[Study on the changes in serum leukotrienes B4 and p38 mitogen activated protein kinase in multiple organ dysfunction syndrome]

OBJECTIVE

To investigate the changes in serum leukotrienes B4(LTB4) and p38 mitogen activated protein kinase (p38 MAPK) in multiple organ dysfunction syndrome (MODS) and to evaluate the relationship between LTB4 and p38 MAPK and clinical condition of patients with MODS.

METHODS

The clinical condition of 26 patients with MODS was evaluated with scoring system. The serum LTB4 and p38 MAPK of the said patients and that of 12 healthy individuals were determined with enzyme linked immunoadsorbent assay(ELISA). The correlation of the scores of MODS and levels of serum LTB4 and p38 MAPK was analyzed. The correlation of the scores of MODS and levels of serum LTB4 and p38 MAPK was analyzed in non-survivors and survivors.

RESULTS

The serum level of LTB4[(923.96+/-308.65)ng/L] was significantly lower in MODS patients compared with control group [(2 453.31+/-400.93)ng/L, P<0.05]. There was no significant difference in serum level of p38 MAPK between the patients with MODS [(193.83+/-106.32)ng/L]ls and control group [(124.36+/- 84.50)ng/L, P>0.05]. There was significant difference in the serum level of LTB4 between the survivors[(1 334.51+/-530.35)ng/L] and non-survivors [(444.98+/-206.30)ng/L, P<0.05]. There were significant negative correlations between serum LTB4 and MODS scores (P<0.001).

CONCLUSION

The pathophysiological changes in later period of MODS are different from those of other common inflammatory responses. Serum LTB4 and p38 MAPK could be one of the indexes of the severity and prognosis on MODS.

Binding of low density lipoprotein to platelet apolipoprotein E receptor 2' results in phosphorylation of p38MAPK

Binding of low density lipoprotein (LDL) to platelets enhances platelet responsiveness to various aggregation-inducing agents. However, the identity of the platelet surface receptor for LDL is unknown. We have previously reported that binding of the LDL component apolipoprotein B100 to platelets induces rapid phosphorylation of p38 mitogen-activated protein kinase (p38MAPK). Here, we show that LDL-dependent activation of this kinase is inhibited by receptor-associated protein (RAP), an inhibitor of members of the LDL receptor family. Confocal microscopy revealed a high degree of co-localization of LDL and a splice variant of the LDL receptor family member apolipoprotein E receptor-2 (apoER2') at the platelet surface, suggesting that apoER2' may contribute to LDL-induced platelet signaling. Indeed, LDL was unable to induce p38MAPK activation in platelets of apoER2-deficient mice. Furthermore, LDL bound efficiently to soluble apoER2', and the transient LDL-induced activation of p38MAPK was mimicked by an anti-apoER2 antibody. Association of LDL to platelets resulted in tyrosine phosphorylation of apoER2', a process that was inhibited in the presence of PP1, an inhibitor of Src-like tyrosine kinases. Moreover, phosphorylated but not native apoER2' co-precipitated with the Src family member Fgr. This suggests that exposure of platelets to LDL induces association of apoER2' to Fgr, a kinase that is able to activate p38MAPK. In conclusion, our data indicate that apoER2' contributes to LDL-dependent sensitization of platelets.