Endothelial ß-catenin upregulation and Y142 phosphorylation drive diabetic angiogenesis via upregulating KDR/HDAC9.

BACKGROUND: Diabetic angiogenesis is closely associated with disabilities and death caused by diabetic microvascular complications. Advanced glycation end products (AGEs) are abnormally accumulated in diabetic patients and are a key pathogenic factor for diabetic angiogenesis. The present study focuses on understanding the mechanisms underlying diabetic angiogenesis and identifying therapeutic targets based on these mechanisms. METHODS: In this study, AGE-induced angiogenesis serves as a model to investigate the mechanisms underlying diabetic angiogensis. Mouse aortic rings, matrigel plugs, and HUVECs or 293T cells were employed as research objects to explore this pathological process by using transcriptomics, gene promoter reporter assays, virtual screening and so on. RESULTS: Here, we found that AGEs activated Wnt/ß-catenin signaling pathway and enhanced the ß-catenin protein level by affecting the expression of ß-catenin degradation-related genes, such as FZDs (Frizzled receptors), LRPs (LDL Receptor Related Proteins), and AXIN1. AGEs could also mediate ß-catenin Y142 phosphorylation through VEGFR1 isoform5. These dual effects of AGEs elevated the nuclear translocation of ß-catenin and sequentially induced the expression of KDR (Kinase Insert Domain Receptor) and HDAC9 (Histone Deacetylase 9) by POU5F1 and NANOG, respectively, thus mediating angiogenesis. Finally, through virtual screening, Bioymifi, an inhibitor that blocks VEGFR1 isoform5-ß-catenin complex interaction and alleviates AGE-induced angiogenesis, was identified. CONCLUSION: Collectively, this study offers insight into the pathophysiological functions of ß-catenin in diabetic angiogenesis.

Advanced glycation end products induce endothelial hyperpermeability via ß-catenin phosphorylation and subsequent up-regulation of ADAM10.

Endothelial hyperpermeability is the initial event in the development of diabetic microvascular complications, and advanced glycation end products (AGEs) are suggested to cause much of the endothelial hyperpermeability associated with diabetes mellitus, but the molecular mechanism remains to be characterized. ß-catenin reportedly plays dual functions in maintaining normal endothelial permeability by serving both as an adhesive component and a signal transduction component. Here, we found that AGEs induced the phosphorylation of ß-catenin at residues Y654 and Y142 and the endothelial hyperpermeability was reversed when the two residues were blocked. In mechanism, phosphorylation of Y654 was blocked by Src inactivation, whereas phosphorylation of Y142 was reduced by a focal adhesion kinase inhibitor. ß-catenin Y654 phosphorylation induced by AGEs facilitated the dissociation of vascular endothelial (VE)-cadherin/ß-catenin and the impairment of adherens junctions (AJs), whereas ß-catenin Y142 phosphorylation favoured the dissociation of ß-catenin and α-catenin. Further investigation revealed that ß-catenin Y142 phosphorylation was required for AGEs-mediated ß-catenin nuclear translocation, and this nuclear-located ß-catenin subsequently activated the TCF/LEF pathway. This pathway promotes the transcription of the Wnt target, ADAM10 (a disintegrin and metalloprotease 10), which mediates VE-cadherin shedding and leads to further impairment of AJs. In summary, our study showed the role of ß-catenin Y654 and Y142 phosphorylation in AGEs-mediated endothelial hyperpermeability through VE-cadherin/ß-catenin/α-catenin dissociation and up-regulation of ADAM10, thereby advancing our understanding of the underlying mechanisms of AGEs-induced microvascular hyperpermeability.

Interface-sensitized prodrug nanoaggregate as an effective in situ antitumor vaccine.

In situ antitumor vaccines have been widely explored as an effective strategy to inhibit tumor growth by stimulating antitumor immune responses. Herein, we reported a simple and effective in situ antitumor vaccine, which was prepared by co-assembling cationic lipids (DOTAP) with the disulfide bond-linked lipid-drug conjugates of camptothecin and resiquimod. The resulting vaccine had a rod-sharped morphology with nanoscale sizes (average hydrodynamic diameter of ∼163.7 nm) and positively-charged interfaces (zeta potential ∼ +36.2 mV). The interfacial cationization of nanoaggregate resulted in 1000 folds faster redox-responsive drug release than that of unmodified ones, which induced a much more potent in vivo antitumor immune by accelerating the glutathione-responsive drug release at the tumor site. Such cationic lipid-drug nanoaggregates displayed many benefits, such as high co-loading capacity, simple preparation process, and wide applicability, which would serve as a promising new approach to design effective in situ antitumor vaccines.

Kinetically-stable small-molecule prodrug nanoassemblies for cancer chemotherapy.

Self-delivering nanocarrier based on the small-molecule prodrug nanoassemblies (NAs) have been widely used for the efficient delivery of chemotherapeutics, but the effect of kinetic stability of NAs on their delivery performance has not been illuminated. In this study, two camptothecin (CPT)-oleic acid (OA) prodrugs were used to fabricate self-assembling nanorods with similar size distribution, zeta potential and morphology but having sharply different kinetic stability, which provided an ideal platform to investigate the effects of kinetic stability. It is found that the nanorods with high kinetic stability showed a lower in vitro cytotoxicity, but were more effective to inhibit the tumor growth probably by decreasing the premature CPT release and subsequent generation of the inactive carboxylate CPT. However, such kinetically stable nanorods also resulted in the increased toxicity, probably due to the high prodrug accumulation in tissues after multiple injections. These results outlined the pivotal role of kinetic stability in determining antitumor efficacy of prodrug NAs, which provided a new insight into the delivery mechanism for the small-molecule prodrug self-delivering nanosystems.

Role of the Receptor for Advanced Glycation End Products in Heat Stress-Induced Endothelial Hyperpermeability in Acute Lung Injury.

OBJECTIVE: To study the role of the receptor for advanced glycation end products (RAGE) in endothelial barrier dysfunction induced by heat stress, to further explore the signal pathway by which RAGE contributes to heat-induced endothelia response, and thereby find a novel target for the clinical treatment of ALI (acute lung injury) induced by heatstroke. METHODS: This study established the animal model of heatstroke using RAGE knockout mice. We observed the role of RAGE in acute lung injury induced by heatstroke in mice by evaluating the leukocytes, neutrophils, and protein concentration in BALF (Bronchoalveolar lavage fluids), lung wet/dry ratio, histopathological changes, and the morphological ultrastructure of lung tissue and arterial blood gas analysis. To further study the mechanism, we established a heat stress model of HUVEC and concentrated on the role of RAGE and its signal pathway in the endothelial barrier dysfunction induced by heat stress, measuring Transendothelial electrical resistance (TEER) and western blot. RESULTS: RAGE played a key role in acute lung injury induced by heatstroke in mice. The mechanism C-Jun is located in the promoter region of the RAGE gene. C-Jun increased the RAGE protein expression while HSF1 suppressed RAGE protein expression. The overexpressed RAGE protein then increased HUVEC monolayer permeability by activating ERK and P38 MAPK under heat stress. CONCLUSION: This study indicates the critical role of RAGE in heat stress-induced endothelial hyperpermeability in acute lung injury and suggests that RAGE could be a potential therapeutic target in protecting patients against acute lung injury induced by heatstroke.

The modulation relationship of genomic pattern of intratumor heterogeneity and immunity microenvironment heterogeneity in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world, with the second highest mortality rate among all cancer types. Growing evidence has demonstrated the notable effects of intratumor heterogeneity (ITH) and tumor immune microenvironment heterogeneity (TIMH) on the biological processes involved in HCC. However, the interactive mechanisms between ITH and TIMH is still unclear. The present study systematically screened the mRNA expression, simple nucleotide variation data and clinical data of samples from The Cancer Genome Atlas (TCGA). The mutant-allele tumor heterogeneity (MATH) score was used to represent ITH, and TCGA cohort was divided into two groups according to the MATH score. Next, different immune-related signaling pathways and enriched immune-related genes were identified using Gene Set Enrichment Analysis of these two groups, and the results revealed that interleukin-1α (IL1A) and serine/threonine-protein kinase PAK4 were associated with prognosis. Furthermore, CIBERSORT was utilized to calculate the fractions of 22 types of leukocytes to represent TIMH, and the fractions of M1 and M2 macrophages were confirmed to be associated with prognosis. Therefore, PAK4, interleukin-1α (IL1A), and M1/M2 ratio were selected as the key factors involved in the interaction between ITH and TIMH. Afterwards, microRNAs (miRNAs) that were linearly related to the M1/M2 ratio and the potential target genes of the miRNAs were screened. Finally, the regulatory network between PAK4, IL1A, and the M1/M2 ratio was established, bridged by the above miRNAs and the target genes. In addition, PAK4, heat shock protein 105 kDa and miRNA-1911 were demonstrated to be a key factor involved in immune response via Weighted Correlation Network Analysis in HCC.

Mdia1 is Crucial for Advanced Glycation End Product-Induced Endothelial Hyperpermeability.

BACKGROUND/AIMS: Disruption of endothelial barrier integrity in response to advanced glycation end products (AEGs) stimulation contributes to vasculopathy associated with diabetes mellitus. Mammalian diaphanous-related formin (mDia1) has been reported to bind to the cytoplasmic domain of the receptor for advanced glycation end products (RAGE), which induces a series of cellular processes. This study directly evaluated the participation of mDia1 in AGE-induced hyperpermeability and revealed the precise intracellular signal transductions of this pathological process. METHODS: Human umbilical vein endothelial cells (HUVECs) were used in the in vitro studies. Trans-endothelial electric resistance and permeability coefficient for dextran (Pd) were measured to analyze cell permeability. Western blotting, immunofluorescence staining and flow cytometry assay were performed to investigate the underlying mechanism. Dextran flux across the mesentery in mice was monitored to investigate in vivo microvascular permeability. RESULTS: we found that AGEs evoked Nox4 membrane translocation, reactive oxygen species production, phosphorylation of Src and VE-cadherin, dissociation of adherens junctions and eventual endothelial hyperpermeability through RAGE-mDia1 binding. Cells overexpressing mDia1 by recombinant adenovirus infection showed stronger cellular responses induced by AGEs. Down-regulation of mDia1 by infection with an adenovirus encoding siRNA or blockade of RAGE-mDia1 binding by transfection with RAGE mutant plasmids into HUVECs abolished these AGE-induced effects. Furthermore, knockdown of mDia1 using an adenovirus or genetical knockout of RAGE in C57 mice rescued AGE-evoked microvascular hyperpermeability. CONCLUSION: Our study revealed that mDia1 plays a critical role in AGE-induced microvascular hyperpermeability through binding to RAGE.

Oxidative stress regulates mitogen­activated protein kinases and c­Jun activation involved in heat stress and lipopolysaccharide­induced intestinal epithelial cell apoptosis.

Heat stress and gut­derived endotoxinemia are common causes of multiple organ dysfunction syndrome in heat stroke patients. Evidence has demonstrated that cell apoptosis in the small intestine serves an important role in the pathogenesis of heatstroke, which leads to increased intestinal permeability to endotoxin or lipopolysaccharides (LPS) from the gut entering the circulation. However, little is known about the potential underlying mechanisms mediating heat stress combined with LPS­induced intestinal epithelial cell apoptosis. In the present study, LPS combined with heat stress induced production of reactive oxygen species (ROS), mitochondrial membrane potential disruption and cell apoptosis, which eventually led to increased intestinal permeability and reduced epithelial resistance in the IEC­6 cell line. Inductions in ROS, mitochondrial membrane potential disruption and cell apoptosis were detected by using an ROS assay kit, 5,5',6,6'­tetrachloro­1,1',3,3'tetraethylbenzimidazo carbocyanine iodide dye kit and annexin V­fluorescein isothiocyanate apoptosis kit, respectively. The effect of ROS on mitogen activated protein kinases (MAPKs) and c­Jun activation was investigated using the antioxidant drug, butylated hydroxyanisole (BHA) by western blotting. The results of the present study demonstrated that ROS is essential to activate p38, extracellular signal­regulated kinase (ERK) and c­Jun, but not c­Jun N­terminal kinase (JNK), in LPS combined with heat stress treated cells. Furthermore, ROS, and activation of p38, JNK and c­Jun, were revealed to serve pro­apoptosis roles which aggravated damage to epithelial barrier integrity, as assessed by flow cytometry using Annexin V­fluorescein isothiocyanate staining and pretreatment of cells with specific inhibitors of ROS, JNK, p38 and c­Jun (BHA, SP600125, SB203580 and c­Jun peptide, respectively). Transepithelial electrical resistance and horseradish peroxidase permeability were detected in cells treated with LPS combined with heat stress, which revealed that ERK serves an anti­apoptosis role, as determined by pretreatment of cells with PD98059, a specific inhibitor of ERK. In conclusion, these findings suggested a novel role of the ROS signaling pathway which involved activation of MAPKs and c­Jun, following LPS combined with heat stress­induced IEC­6 cell apoptosis and impairment of the epithelial barrier. These results may facilitate understanding of pathological conditions involving ROS, such as heat stroke.

PAR1­mediated c­Jun activation promotes heat stress­induced early stage apoptosis of human umbilical vein endothelial cells.

Our previous study indicated that when human umbilical vein endothelial cells (HUVECs), which are involved in endothelial barrier function, are heat stressed, levels of protease­activated receptor 1 (PAR1) are increased significantly. In the present study, it was demonstrated that PAR1 serves a vital role in heat stress­induced HUVEC apoptosis. When the PAR1 inhibitor, SCH79797 (SCH), or a small interfering RNA (siRNA) targeting PAR1 were used to inhibit PAR1 signaling, a marked decrease in cell apoptosis, caspase­3 activity and the expression of the pro­apoptotic protein B­cell lymphoma 2 (Bcl­2) associated X (Bax), as well as increased expression of the anti­apoptotic Bcl­2 family member, myeloid cell leukemia 1 (Mcl­1), were observed. In addition, heat stress­induced apoptosis, caspase­3 activity and the expression of Bax were significantly increased following administration of the PAR1 agonist, TFLLR­NH2 or adenovirus overexpression of PAR1. This was accompanied by decreased protein expression levels of Mcl­1. Furthermore, it was identified that the DNA binding activity of the nuclear factor (NF)­κB p65 subunit increased and c­Jun activation was reduced as a result of inhibition of PAR1 signaling by SCH or siRNA­mediated PAR1 knockdown in heat stress­induced HUVECs. Additionally, our previous study reported that NF­κB p65 activation may have an anti­apoptosis effect on heat stressed HUVECs, whereas in the present study c­Jun activation had a pro­apoptosis effect on heat stressed HUVECs. Taken together, these results indicated that PAR1 signaling­mediated c­Jun activation promotes early apoptosis of HUVEC cells induced by heat stress.

Role of myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability in vitro and in vivo.

We have previously reported that advanced glycation end products activated Rho-associated protein kinase and p38 mitogen-activated protein kinase, causing endothelial hyperpermeability. However, the mechanisms involved were not fully clarified. Here, we explored the role of myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability. Myosin light chain phosphorylation significantly increased by advanced glycation end products in endothelial cells in a time- and dose-dependent manner, indicating that myosin light chain phosphorylation is involved in the advanced glycation end product pathway. Advanced glycation end products also induced myosin phosphatase-targeting subunit 1 phosphorylation, and small interfering RNA knockdown of the receptor for advanced glycation end products, or blocking myosin light chain kinase with its inhibitor, ML-7, or small interfering RNA abated advanced glycation end product-induced myosin light chain phosphorylation. Advanced glycation end product-induced F-actin rearrangement and endothelial hyperpermeability were also diminished by inhibition of receptor for advanced glycation end product or myosin light chain kinase signalling. Moreover, inhibiting myosin light chain kinase with ML-7 or blocking receptor for advanced glycation end product with its neutralizing antibody attenuated advanced glycation end product-induced microvascular hyperpermeability. Our findings suggest a novel role for myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability.

[Protective effects of ulinastatin against acute lung injury induced by heatstroke in mice].

OBJECTIVE: To investigate the protective effect of ulinastatin (UTI) against acute lung injury induced by heatstroke in mice. METHODS: Sixty C57/BL6 mice were randomly divided into 6 groups, with 10 mice in each: control group, heatstroke group, UTI pretreatment group, saline pretreatment group, UTI post-treatment group, saline post-treatment group. The control mice were housed at a controlled room temperature of (22∓1) degrees; celsius, and the other groups were placed inside a temperature and humidity controlled chamber pre-set at 37 degrees; celsius and 60%. The two UTI groups were intraperitoneally injected with UTI at 5×10(4) U/kg 10 min before or after heat stress, and the two saline groups were given then equal amounts of saline in the same manner. The core body temperature of mice was monitored by a mercury thermometer every 30 min in the first 1.5 h during heating. The core temperature was measured, then every 15 min until it reached 42.7 degrees; celsius, which was taken as the onset of heatstroke. The animals were allowed to recover passively at ambient temperature for 6 h. The lung histopathological changes, protein concentration in BALF, lung wet/dry weight ratios, lung water content, and pulmonary microvascular permeability were assayed after 6 h of recovery at 37 degrees;celsius. RESULTS: Compared with the control group, the heatstroke model group and two saline groups displayed more severe lung damage and pathological morphology changes, and the lung wet/dry weight ratio, protein concentration in BALF, lung water content and pulmonary microvascular permeability were also significantly increased. These effects were significantly alleviated in UTI treated group. Pretreat ment with UTI significantly prolonged the time to Tc≥42.7 degrees; celsius but had no effect on lung injury induced by heatstroke. CONCLUSION: UTI can reduce the pulmonary edema and inflammatory exudation in acute lung injury caused by heatstroke.

Role of Src in Vascular Hyperpermeability Induced by Advanced Glycation End Products.

The disruption of microvascular barrier in response to advanced glycation end products (AGEs) stimulation contributes to vasculopathy associated with diabetes mellitus. Here, to study the role of Src and its association with moesin, VE-cadherin and focal adhesion kinase (FAK) in AGE-induced vascular hyperpermeability, we verified that AGE induced phosphorylation of Src, causing increased permeability in HUVECs. Cells over-expressed Src displayed a higher permeability after AGE treatment, accompanied with more obvious F-actin rearrangement. Activation of Src with pcDNA3/flag-Src(Y530F) alone duplicated these effects. Inhibition of Src with siRNA, PP2 or pcDNA3/flag-Src(K298M) abolished these effects. The pulmonary microvascular endothelial cells (PMVECs) isolated from receptor for AGEs (RAGE)-knockout mice decreased the phosphorylation of Src and attenuated the barrier dysfunction after AGE-treatment. In vivo study showed that the exudation of dextran from mesenteric venules was increased in AGE-treated mouse. This was attenuated in RAGE knockout or PP2-pretreated mice. Up-regulation of Src activity induced the phosphorylation of moesin, as well as activation and dissociation of VE-cadherin, while down-regulation of Src abolished these effects. FAK was also proved to interact with Src in HUVECs stimulated with AGEs. Our studies demonstrated that Src plays a critical role in AGE-induced microvascular hyperpermeability by phosphorylating moesin, VE-cadherin, and FAK respectively.

NF-κB signaling is essential for resistance to heat stress-induced early stage apoptosis in human umbilical vein endothelial cells.

Cell apoptosis induced by heat stress is regulated by a complex signaling network. We previously reported that a p53-dependent pathway is involved. Here, we present evidence that NF-κB signaling plays a crucial role in preventing heat stress-induced early apoptosis. Human umbilical vein endothelial cells (HUVECs) were examined and increased phosphorylation of p65 and IκBα were detected, without IκBα degradation. When NF-κB signaling was inhibited by BAY11-7082, or a small interference RNA (siRNA) targeting p65, a significant increase in cell apoptosis and caspase-3 activity was observed, as well as reduced expression and translocation of HSP27 into the nucleus, an accumulation of reactive oxygen species, and prolonged phosphorylation of mitogen-activated protein kinases (MAPKs). In addition, an association between HSP27 and p65 was identified which may enhance NF-κB activation. When HSP27 was overexpressed, pretreatment of HUVECs with the antioxidant, apocynin, or N-acetyl cysteine, suppressed apoptosis. Similarly, inhibition of JNK and p38 with SP600125 and SB203580, respectively, also suppressed apoptosis, whereas siRNA-mediated HSP27 knockdown and treatment with the ERK 1/2 inhibitor PD98059 did otherwise. In conclusion, these findings suggest a novel role for an NF-κB signaling pathway involving HSP27, ROS, and MAPKs that confers a protective effect against heat stress-induced cell apoptosis.

[Mechanism of continuous venovenous hemofiltration combined with ulinastatin for the treatment of septic shock].

OBJECTIVE: To investigate the molecular mechanisms of continuous venovenous hemofiltration (CVVH) combined with ulinastatin (ULI) (CVVH-ULI) for the treatment of septic shock. METHODS: Human umbilical endothelial cells (HUVECs) were incubated with serums isolated from normal healthy people (control), septic shock patients treated with conventional therapy (CT) or treated with CVVH combined with ULI (CVVH-ULI). Endothelial permeability was evaluated by the leakage of FITC-labeled albumin. The morphological changes of F-actin was evaluated by Rhodamine-phalloidin. The phosphorylated levels of p38 were determined by Western blot. Cells were then treated with p38inhibitor (SB203580), or DMSO, followed by incubation with serum from septic shock patients treated with conventional therapy. Endothelial permeability and F-actin rearrangements were also evaluated as noted above. RESULTS: Serum from CT group increased endothelial permeability, F-actin rearrangements, and phosphorylated levels of p38, which were inhibited by CVVH-ULI treatment. Moreover, in CT group, the serum-induced endothelial hyperpermeability and F-actin rearrangements were inhibited by SB203580, the inhibitor of p38. CONCLUSION: CVVH combined with ulinastatin decreases endothelial hyperpermeability induced by septic shock through inhibiting p38 MAPK pathways.

Inhibition of microRNA-497 ameliorates anoxia/reoxygenation injury in cardiomyocytes by suppressing cell apoptosis and enhancing autophagy.

MiR-497 is predicted to target anti-apoptosis gene Bcl2 and autophagy gene microtubule-associated protein 1 light chain 3 B (LC3B), but the functional consequence of miR-497 in response to anoxia/reoxygenation (AR) or ischemia/reperfusion (IR) remains unknown. This study was designed to investigate the influences of miR-497 on myocardial AR or IR injury. We noted that miR-497 was enriched in cardiac tissues, while its expression was dynamically changed in murine hearts subjected to myocardial infarction and in neonatal rat cardiomyocytes (NRCs) subjected to AR. Forced expression of miR-497 (miR-497 mimic) induced apoptosis in NRCs as determined by Hoechst staining and TUNEL assay. In response to AR, silencing of miR-497 using a miR-497 sponge significantly reduced cell apoptosis and enhanced autophagic flux. Furthermore, the infarct size induced by IR in adenovirus (Ad)-miR-497 sponge infected mice was significantly smaller than in mice receiving Ad-vector or vehicle treatment, while Ad-miR-497 increased infarct size. The expression of Bcl-2 and LC3B-II in NRCs or in murine heart was significantly decreased by miR-497 mimic and enhanced by miR-497 sponge. These findings demonstrate that inhibition of miR-497 holds promise for limiting myocardial IR injury.

Xuebijing injection reduces organ injuries and improves survival by attenuating inflammatory responses and endothelial injury in heatstroke mice.

BACKGROUND: The pathogenesis of heatstroke is a multi-factorial process involved with an interplay among subsequent inflammation, endothelial injury and coagulation disturbances, which makes pharmacological therapy of heatstroke a challenging problem. Xuebijing injection (XBJ), a traditional Chinese medicine used to sepsis, has been reported to suppress inflammatory responses and restore coagulation disturbances. However, little is known about the role of XBJ in heatstroke. METHODS: Mice were treated with indicated dose of XBJ before and/or after the induction of heatstroke. Serum inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and endothelial markers, von Willebrand Factor (vWF) and E-selectin, were measured by ELISA. Liver, kidney and heart profiles including alanine aminotransferase, aspartic aminotransferase, creatinine, blood urea nitrogen, and lactate dehydrogenase, were evaluated by UniCel DxC 800 Synchron Clinical Systems, and troponin was measured by ELISA. Coagulation profiles, including thrombin time, prothrombin time, activated partial thromboplastin time, international normalized ratio, and fibrinogen were examined by STA Compact® Hemostasis System. Jejunum injury was evaluated with H&E staining. Changes in mitochondrial structure in cardiac tissue were assesed by electron microscopy. RESULTS: Pretreatment with XBJ decreased serum pro-inflammatory cytokines including TNF-α and IL-6, as well as endothelial injury markers, vWF and E-selectin, in a dose-dependent manner in heatstroke mice. Similar protective effects were observed when XBJ was administered after, or both before and after heat insult. These protective effects lasted for over 12 h in mice receiving XBJ before and after heat insult. XBJ also improved survival rates in heatstroke mice, ameliorated liver, heart, and kidney injuries, including mitochondrial damage to the heart, and reduced coagulation disturbances. CONCLUSIONS: XBJ prevents organ injuries and improves survival in heatstroke mice by attenuating inflammatory responses and endothelial injury. XBJ may be a potentially useful in the prevention and treatment of heatstroke.

Pharmacological modulation of autophagy to protect cardiomyocytes according to the time windows of ischaemia/reperfusion.

BACKGROUND AND PURPOSE: Targeted modulation of autophagy induced by myocardial ischaemia/reperfusion has been the subject of intensive investigation, but it is debatable whether autophagy is beneficial or harmful. Hence, we evaluated the effects of pharmacological manipulation of autophagy on the survival of cardiomyocytes in different time windows of ischaemia/reperfusion. EXPERIMENTAL APPROACH: We examined the autophagy and apoptosis in cardiomyocytes subjected to different durations of anoxia/re-oxygenation or ischaemia/reperfusion, and evaluated the effects of the autophagic enhancer rapamycin and inhibitor wortmannin on cell survival. KEY RESULTS: In neonatal rat cardiomyocytes (NRCs) or murine hearts, autophagy was increased in response to anoxia/reoxygenation or ischaemia/reperfusion in a time-dependent manner. Rapamycin-enhanced autophagy in NRCs led to higher cell viability and less apoptosis when anoxia was sustained for ≦ 6 h. When anoxia was prolonged to 12 h, rapamycin did not increase cell viability, induced less apoptosis and more autophagic cell death. When anoxia was prolonged to 24 h, rapamycin increased autophagic cell death, while wortmannin reduced autophagic cell death and apoptosis. Similar results were obtained in mice subjected to ischaemia/reperfusion. Rapamycin inhibited the opening of mitochondrial transition pore in NRCs exposed to 6 h anoxia/4 h re-oxygenation but did not exert any effect when anoxia was extended to 24 h. Similarly, rapamycin reduced the myocardial expression of Bax in mice subjected to short-time ischaemia, but this effect disappeared when ischaemia was extended to 24 h. CONCLUSIONS AND IMPLICATIONS: The cardioprotection of autophagy is context-dependent and therapies involving the modification of autophagy should be determined according to the duration of ischaemia/reperfusion.

Heat stress-induced disruption of endothelial barrier function is via PAR1 signaling and suppressed by Xuebijing injection.

Increased vascular permeability leading to acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is central to the pathogenesis of heatstroke. Protease-activated receptor 1 (PAR1), the receptor for thrombin, plays a key role in disruption of endothelial barrier function in response to extracellular stimuli. However, the role of PAR1 in heat stress-induced endothelial hyper-permeability is unknown. In this study, we measured PAR1 protein expression in heat-stressed human umbilical venous endothelial cells (HUVECs), investigated the influences of PAR1 on endothelial permeability, F-actin rearrangement, and moesin phosphorylation by inhibiting PAR1 with its siRNA, neutralizing antibody (anti-PAR1), specific inhibitor(RWJ56110), and Xuebijing injection (XBJ), a traditional Chinese medicine used for sepsis treatment, and evaluated the role of PAR1 in heatstroke-related ALI/ARDS in mice by suppressing PAR1 with RWJ56110, anti-PAR1and XBJ. We found that heat stress induced PAR1 protein expression 2h after heat stress in endothelial cells, caused the release of endothelial matrix metalloprotease 1, an activator of PAR1, after 60 or 120 min of heat stimulation, as well as promoted endothelial hyper-permeability and F-actin rearrangement, which were inhibited by suppressing PAR1 with RWJ56110, anti-PAR1 and siRNA. PAR1 mediated moesin phosphorylation, which caused F-actin rearrangement and disruption of endothelial barrier function. To corroborate findings from in vitro experiments, we found that RWJ56110 and the anti-PAR1 significantly decreased lung edema, pulmonary microvascular permeability, protein exudation, and leukocytes infiltrations in heatstroke mice. Additionally, XBJ was found to suppress PAR1-moesin signal pathway and confer protective effects on maintaining endothelial barrier function both in vitro and in vivo heat-stressed model, similar to those observed above with the inhibition of PAR1. These results suggest that PAR1 is a potential therapeutic target in heatstroke.

Blockage of protease-activated receptor 1 ameliorates heat-stress induced intestinal high permeability and bacterial translocation.

Accumulated evidences indicate intestinal lesions play an important role in the pathogenesis of heatstroke. However, the underlying mechanisms by which heat stress causes intestinal barrier dysfunction and bacterial translocation remain unclear. In this study, we investigated the role of protease-activated receptor 1 (PAR1) in heat stress-induced intestinal hyper-permeability and bacterial translocation. Intestinal permeability in heat stressed mouse was evaluated by determining plasma endotoxin concentration and urinal lactulose/mannitol (L/M) ratio with gastric administration of L/M solution. Venous blood, liver, spleen and mesenteric lymph node tissues were collected for bacterial load test. Real time PCR was used to determine ileum PAR1 mRNA expression. In vitro study, permeability was assessed by determining trans-epithelial electrical resistance (TEER) in human intestinal Caco-2 cell line. RWJ-58259, a selective antagonist of PAR1, was used both in vivo and in vitro studies. The results showed that heat stress could increase ileum PAR1 mRNA level, urinal L/M ratio, plasma endotoxin concentration and bacterial load in the blood, spleen and mesenteric lymph nodes. Blocking PAR1 with RWJ-58259 (10 mg/kg) pretreatment could significantly reduce heat stress-induced above changes, but have no role to PAR1 mRNA level. In Caco-2 cells, heat stress-induced high permeability could also be reduced by RWJ-58259 (5-20 µmol/L). In summary, our results demonstrated that PAR1 signaling pathway may play an important role in the heat stress-induced elevation of intestinal permeability, bacterial translocation and the occurrence of endotoxemia.

Identification of phosphorylated MYL12B as a potential plasma biomarker for septic acute kidney injury using a quantitative proteomic approach.

Acute kidney injury (AKI) is a common and increasingly encountered complication in hospitalized patients with critical illness in intensive care units (ICU). According to the etiology, Sepsis-induced AKI (SAKI) is a leading contributor to AKI and significantly has very poor prognosis, which might be related to the late detection when the elevation of BUN and serum creatinine (SCr) is used. Many genes are up-regulated in the damaged kidney with the corresponding protein products appearing in plasma and urine. Some of these are candidate biomarkers for more timely diagnosis of SAKI. Therefore, extensive research efforts over this past decade have been directed at the discovery and validation of novel SAKI biomarkers to detect injury prior to changes in kidney function, a number of serum and urinary proteins, including NGAL, KIM-1, cystatin-C, IL-18, and L-FABP, have been identified for predicting SAKI before a rise in BUN and serum creatinine in several experimental and clinical trainings. Unfortunately, an ideal biomarker of SAKI with highly sensitivity and specificity has not been identified yet. Recent progresses in quantitative proteomics have offered opportunities to discover biomarkers for SAKI. In the present study, kidney tissue samples from SAKI mice were analyzed by two-dimensional differential gel electrophoresis (2D-DIGE), and 4 up-regulated proteins, which were actin (ACTB), myosin regulatory light chain 12B (MYL12B), myosin regulatory light polypeptide 9 (MYL9), and myosin regulatory light chain 12A (MYL12A) were identified by matrix assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). Among all the varied proteins, MYL12B was validated by western blot. Interestingly, there was no change between the SAKI and control kidney tissues, however, phosphorylated MYL12B was detected to be consistent with the proteomics data. Furthermore, phosphorylated MYL12B was found similarly to be increased in SAKI plasma, while MYL12B was changeless in plasma of control group. Taking together, phosphorylated MYL12B may be employed as a potential plasma biomarker for the early diagnosis of SAKI.