Human esophageal microvascular endothelial cells respond to acidic pH stress by PI3K/AKT and p38 MAPK-regulated induction of Hsp70 and Hsp27

Chronic Corticosterone Treatment Decreases Extracellular pH and Increases Lactate Release via PDK4 Upregulation in Cultured Astrocytes

The pathogenesis of stress-related disorders involves aberrant glucocorticoid secretion, and decreased pH and increased lactate in the brain are common phenotypes in several psychiatric disorders. Mice treated with glucocorticoids develop these phenotypes, but it is unclear how glucocorticoids affect brain pH. Therefore, we investigated the effect of corticosterone (CORT), the main glucocorticoid in rodents, on extracellular pH and lactate release in cultured astrocytes, which are the main glial cells that produce lactate in the brain. CORT treatment for one week decreased the extracellular pH and increased the extracellular lactate level via glucocorticoid receptors. CORT also increased the intracellular pyruvate level and upregulated pyruvate dehydrogenase kinase 4 (PDK4), while PDK4 overexpression increased extracellular lactate and decreased the extracellular pH. Furthermore, PDK4 inhibition suppressed the increase in extracellular lactate and the decrease in extracellular pH induced by CORT. These results suggest that increased lactate release via accumulation of intracellular pyruvate in astrocytes by chronic glucocorticoid exposure contributes to decreased brain pH.

Mechanisms of Chinese Medicine in Gastroesophageal Reflux Disease Treatment: Data Mining and Systematic Pharmacology Study

OBJECTIVE

To identify specific Chinese medicines (CMs) that may benefit patients with gastroesophageal reflux disease (GERD), and explore the action mechanism.

METHODS

Domestic and foreign literature on the treatment of GERD with CMs was searched and selected from China National Knowledge Infrastructure, China Science and Technology Journal Database, Wanfang Database, and PubMed from October 1, 2011 to October 1, 2021. Data from all eligible articles were extracted to establish the database of CMs for GERD. Apriori algorithm of data mining techniques was used to analyze the rules of herbs selection and core Chinese medicine formulas were identified. A system pharmacology approach was used to explore the action mechanism of these medicines.

RESULTS

A total of 278 prescriptions for GERD were analyzed, including 192 CMs. Results of Apriori algorithm indicated that Evodiae Fructus and Coptidis Rhizoma were the highest confidence combination. A total of 32 active ingredients and 66 targets were screened for the treatment of GERD. Enrichment analysis showed that the mechanisms of action mainly involved pathways in cancer, fluid shear stress and atherosclerosis, advanced glycation end product (AGE), the receptor for AGE signaling pathway in diabetic complications, bladder cancer, and rheumatoid arthritis.

CONCLUSION

Evodiae Fructus and Coptidis Rhizoma are the core drugs in the treatment of GERD and the potential mechanism of action of these medicines includes potential target and pathways.

Effect of Vicia sativa L. on Motility, Mortality and Expression Levels of hsp Genes in J2 Stage of Meloidogyne hapla

Assuming that the seeds of Vicia sativa L. have a stressful effect on J2 stage Meloidogyne hapla, we undertook research on the effect of these seeds on the motility and mortality of J2 and determined the expression levels of selected hsp genes in J2. The assessment of the effect of V. sativa seeds on the motility of M. hapla specimens consisted of observing the movement of J2 immersed in a seed diffusate or in a tomato root filtrate at temperatures of 10, 17, and 21°C. In J2 treated with V. sativa (cv. Ina) seed diffusates, the expression level of hsp genes was determined by qPCR. J2 exposed to V. sativa diffusates were found to lose their motility, while their mortality did not exceed 30%. J2 in the seed diffusate were characterized by an increase in the expression levels of the Mh-hsp90, Mh-hsp1, and Mh-hsp43 genes. It is suggested that the hsp90 gene may be a potential bioindicator of the environmental impact on Meloidogyne nematodes. The impaired ability to move in J2 of M. hapla is attributable to the occurrence of V. sativa seeds in their habitat. These studies may contribute to developing methods of reducing crop damage caused by M. hapla.

The Role of the Heat-Shock Proteins in Esophagogastric Cancer

Heat-shock proteins (HSPs) are a family of proteins that have received considerable attention over the last several years. They have been classified into six prominent families: high-molecular-mass HSP, 90, 70, 60, 40, and small heat shock proteins. HSPs participate in protein folding, stability, and maturation of several proteins during stress, such as in heat, oxidative stress, fever, and inflammation. Due to the immunogenic host's role in the combat against cancer cells and the role of the inflammation in the cancer control or progression, abnormal expression of these proteins has been associated with many types of cancer, including esophagogastric cancer. This study aims to review all the evidence concerning the role of HSPs in the pathogenesis and prognosis of esophagogastric cancer and their potential role in future treatment options. This narrative review gathers scientific evidence concerning HSPs in relation to esophagus and gastric cancer. All esophagogastric cancer subtypes are included. The role of HSPs in carcinogenesis, prognostication, and therapy for esophagogastric cancer are discussed. The main topics covered are premalignant conditions for gastric cancer atrophic gastritis, Barrett esophagus, and some viral infections such as human papillomavirus (HPV) and Epstein-Barr virus (EBV). HSPs represent new perspectives on the development, prognostication, and treatment of esophagogastric cancer.

Targeting the Hepatic Microenvironment to Improve Ischemia/Reperfusion Injury: New Insights into the Immune and Metabolic Compartments

Hepatic ischemia/reperfusion injury (IRI) is mainly characterized by high activation of immune inflammatory responses and metabolic responses. Understanding the molecular and metabolic mechanisms underlying development of hepatic IRI is critical for developing effective therapies for hepatic IRI. Recent advances in research have improved our understanding of the pathogenesis of IRI. During IRI, hepatocyte injury and inflammatory responses are mediated by crosstalk between the immune cells and metabolic components. This crosstalk can be targeted to treat or reverse hepatic IRI. Thus, a deep understanding of hepatic microenvironment, especially the immune and metabolic responses, can reveal new therapeutic opportunities for hepatic IRI. In this review, we describe important cells in the liver microenvironment (especially non-parenchymal cells) that regulate immune inflammatory responses. The role of metabolic components in the diagnosis and prevention of hepatic IRI are discussed. Furthermore, recent updated therapeutic strategies based on the hepatic microenvironment, including immune cells and metabolic components, are highlighted.

Graphene quantum dots alleviate ROS-mediated gastric damage

The gastrointestinal (GI) tract is one of the major sites for reactive oxygen species generation (ROS). Physiological ROS, lower than the threshold concentration, is beneficial for human physiology to preserve gut functional integrity. However, ROS generated in large quantities in presence of external stimuli overwhelms the cellular antioxidant defense mechanism and results in oxidative damage and associated physiological disorder. Graphene quantum dots (GQDs) are a class of carbon-based nanomaterials that have attracted tremendous attention not only for their tunable optical properties but also for their broad-spectrum antioxidant properties. In this report we have shown that GQDs are highly efficient in scavenging ROS and suppressing stress-induced gastric ulcers by targeting the MMP-9 pathway and reducing the inflammatory burden by suppressing excessive oxidative stress by inducing high caspase activity, overproduction of Bax, and downregulation of BCL2.

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The gastrointestinal tract is one of the major sites for ROS generation

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Graphene quantum dots (GQDs) have broad-spectrum antioxidant properties

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GQDs scavenge the ROS and suppress gastric ulcers by targeting the MMP-9 pathway

Heat Stress-Induced Dysbiosis of Porcine Colon Microbiota Plays a Role in Intestinal Damage: A Fecal Microbiota Profile

The pathological mechanisms of gastrointestinal disorders, including inflammatory bowel disease (IBD), in pigs are poorly understood. We report the induction of intestinal inflammation in heat-stressed (HS) pigs, fecal microbiota transplantation from pigs to mice, and explain the role of microorganisms in IBD. 24 adult pigs were subjected to HS (34 ± 1 °C; 75–85% relative humidity for 24h) while 24 control pigs (CP) were kept at 25 ± 3°C and the same humidity. Pigs were sacrificed on days 1, 7, 14, 21. Colonic content microbiome analyses were conducted. Pseudo-germ-free mice were fed by gavage with fecal microbiota from HS-pigs and CP to induce pig-like responses in mice. From 7 d, HS-pigs exhibited fever and diarrhea, and significantly lower colonic mucosal thickness, crypt depth/width, and goblet cell number. Compared with each control group, the concentration of cortisol in the peripheral blood of HS pigs gradually increased, significantly so on days 7, 14, and 21 (P < 0.01). While the concentration of LPS in HS pigs' peripheral blood was significantly higher on days 7, 14 (P < 0.01), and 21 (P < 0.05) compared with that of the control group. The colonic microbiome composition of HS-pigs was different to that of CP. By day 14, opportunistic pathogens (e.g., Campylobacterales) had increased in HS-pigs. The composition of the colonic microbiome in mice administered feces from HS-pigs was different from those receiving CP feces. Bacteroides were significantly diminished, Akkermansia were significantly increased, and intestinal damage and goblet cell numbers were higher in mice that received HS-pig feces. Moreover, we verified the relevance of differences in the microbiota of the colon among treatments. Heat stress promotes changes in gut microbiome composition, which can affect the colonic microbial structure of mice through fecal microbiota transplantation; the molecular mechanisms require further investigation. This study enhanced our understanding of stress-induced inflammation in the colon and the increase in diarrhea in mammals subjected to prolonged HS. Our results provide useful information for preventing or ameliorating deficits in pig production caused by prolonged exposure to high temperatures.

Modulation of Heat-Shock Proteins Mediates Chicken Cell Survival against Thermal Stress

Heat stress is one of the most challenging environmental stresses affecting domestic animal production, particularly commercial poultry, subsequently causing severe yearly economic losses. Heat stress, a major source of oxidative stress, stimulates mitochondrial oxidative stress and cell dysfunction, leading to cell damage and apoptosis. Cell survival under stress conditions needs urgent response mechanisms and the consequent effective reinitiation of cell functions following stress mitigation. Exposure of cells to heat-stress conditions induces molecules that are ready for mediating cell death and survival signals, and for supporting the cell's tolerance and/or recovery from damage. Heat-shock proteins (HSPs) confer cell protection against heat stress via different mechanisms, including developing thermotolerance, modulating apoptotic and antiapoptotic signaling pathways, and regulating cellular redox conditions. These functions mainly depend on the capacity of HSPs to work as molecular chaperones and to inhibit the aggregation of non-native and misfolded proteins. This review sheds light on the key factors in heat-shock responses for protection against cell damage induced by heat stress in chicken.

Acidic Microenvironment Regulates the Severity of Hepatic Ischemia/Reperfusion Injury by Modulating the Generation and Function of Tregs via the PI3K-mTOR Pathway

Hepatic ischemia/reperfusion injury (HIRI) is a major cause of liver dysfunction and even liver failure after liver transplantation and hepatectomy. One of the critical mechanisms that lead to HIRI is an acidic microenvironment, which develops due to the accumulation of high acid-like substances such as lactic acid and ketone bodies. Previous studies have shown that the adoptive transfer of induced regulatory T cells (iTregs) attenuates HIRI; however, little is known about the function of Tregs in the acidic microenvironment of a HIRI model. In the present study, we examined the effect of acidic microenvironment on Tregs in vitro and in vivo. Here, we report that microenvironment acidification and dysfunction of the liver is induced during HIRI in humans and mice and that an acidic microenvironment can inhibit the generation and function of CD4⁺CD25⁺Foxp3⁺ iTregs via the PI3K/Akt/mTOR signaling pathway. By contrast, the reversal of the acidic microenvironment restored Foxp3 expression and iTreg function. In addition, the results of cell culture in vitro indicated that the proton pump inhibitor omeprazole improves decreased iTreg differentiation caused by the acidic microenvironment, suggesting the potential clinical use of proton pump inhibitors as immunoregulatory therapy in the treatment of HIRI. Furthermore, our findings demonstrate that buffering the acidic microenvironment to attenuate HIRI in mice has an inseparable relationship with Tregs. Thus, an acidic microenvironment is a key regulator in HIRI, involved in modulating the generation and function of Tregs.

Systematic review and meta-analysis: Effect of Helicobacter pylori eradication on chronic spontaneous urticaria

BACKGROUND

Helicobacter pylori (HP) infection is considered to play a role in the pathogenesis of chronic spontaneous urticaria (CSU). However, the efficacy of HP eradication therapy on CSU symptom improvement has not been well established. This meta-analysis was conducted to estimate the association between HP infection and CSU and to evaluate whether HP eradication therapy benefits patients with CSU.

MATERIAL AND METHODS

In October 2018, we searched databases for studies investigating the efficacy of HP eradication therapy for patients with CSU. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled using random effects models.

RESULTS

The meta-analysis included 22 studies with a total of 1385 patients with CSU. When comparing the spontaneous remission of urticarial symptom in patients with HP-positive to HP-negative patients, HP-negative patients showed significantly higher spontaneous remission of urticarial symptoms. (risk ratio 0.39; 95% confidence interval: 0.19-0.81). Among HP-positive CSU patients, remission of CSU was more likely shown in HP eradication therapy group compared to untreated group, aside from achieving HP elimination (risk ratio 2.10; 95% confidence interval: 1.20-3.68). However, there was no significant difference in the remission of CSU whether antibiotic therapy was successful in eradication of HP or not (risk ratio 1.00; 95% confidence interval: 0.65-1.54).

CONCLUSIONS

The results of this meta-analysis show that HP might be associated with the occurrence and persistence of CSU. The effectiveness of HP eradication therapy in suppressing CSU symptoms was significant. Interestingly, we found that resolution of CSU was not associated with successful eradication of HP infection. CSU Patients who were undergone antibiotic therapy for HP eradication showed significant higher CSU remission with or without HP eradication. Further studies are recommended to evaluate the mechanisms associated with relation of HP with CSU.

High-throughput RNA-sequencing identifies mesenchymal stem cell-induced immunological signature in a rat model of corneal allograft rejection

Objective

The immune rejection mediated by CD4⁺ T cell and antigen presenting macrophages is the leading cause of corneal transplantation failure. Bone marrow-derived mesenchymal stem cells (BM-MSCs) possess robust immunomodulatory potentials, and have been shown by us and others to promote corneal allograft survival. However, the immunological mechanism underlying the protective effects of BM-MSCs remains unclear. Therefore, in the current study, this mechanism was investigated in a BM-MSC-treated rat model of corneal allograft rejection, in the hope to facilitate the search for novel interventional targets to corneal allograft rejection.

Methods

Lewis rats were subjected to corneal transplantation and then received subconjunctival injections of BM-MSCs (2×10⁶ cells / 100 μl PBS) immediately and at day 3 post-transplantation. The control group received the injections of PBS with the same volume. The clinical parameters of the corneal allografts, including opacity, edema, and neovascularization, were regularly evaluated after transplantation. On day 10 post-transplantation, the corneal allografts were collected and subjected to flow cytometry and high-throughput RNA sequencing (RNA-seq). GO enrichment and KEGG pathways were analyzed. The quantitative realtime PCR (qPCR) and immunohistochemistry (IHC) were employed to validate the expression of the selected target genes at transcript and protein levels, respectively.

Results

BM-MSC subconjunctival administration prolonged the corneal allograft survival, with reduced opacity, alleviated edema, and diminished neovascularization. Flow cytometry showed reduced CD4⁺ T cells and CD68⁺ macrophages as well as boosted regulatory T cells (Tregs) in the BM-MSC-treated corneal allografts as compared with the PBS-treated counterparts. Moreover, the RNA-seq and qPCR results demonstrated that the transcript abundance of Cytotoxic T-Lymphocyte Associated Protein 4 (Ctla4), Protein Tyrosine Phosphatase, Receptor Type C (Ptprc), and C-X-C Motif Chemokine Ligand 9 (Cxcl9) genes were increased in the allografts of BM-MSC group compared with PBS group; whereas the expression of Heat Shock Protein Family A (Hsp70) Member 8 (Hspa8) gene was downregulated. The expression of these genes was confirmed by IHC at protein level.

Conclusion

Subconjunctival injections of BM-MSCs promoted corneal allograft survival, reduced CD4⁺ and CD68⁺ cell infiltration, and enriched Treg population in the allografts. The BM-MSC-induced upregulation of Ctla4, Ptprc, Cxcl9 genes and downregulation of Hspa8 gene might contribute to the protective effects of BM-MSCs and subserve the potential interventional targets to corneal allograft rejection.

Hsp74/14-3-3σ Complex Mediates Centrosome Amplification by High Glucose, Insulin, and Palmitic Acid

It has been reported recently that type 2 diabetes promotes centrosome amplification via 14-3-3σ/ROCK1 complex. In the present study, 14-3-3σ interacting proteins are characterized and their roles in the centrosome amplification by high glucose, insulin, and palmitic acid are investigated. Co-immunoprecipitation in combination with MS analysis identified 134 proteins that interact with 14-3-3σ, which include heat shock 70 kDa protein 4 (Hsp74). Gene ontology analyses reveal that many of them are enriched in binding activity. Kyoto Encyclopedia of Genes and Genomes analysis shows that the top three enriched pathways are ribosome, carbon metabolism, and biosynthesis of amino acids. Molecular and functional investigations show that the high glucose, insulin, and palmitic acid increase the expression and binding of 14-3-3σ and Hsp74 as well as centrosome amplification, all of which are inhibited by knockdown of 14-3-3σ or Hsp74. Moreover, molecular docking analysis shows that the interaction between the 14-3-3σ and the Hsp74 is mainly through hydrophobic contacts and a lesser degree ionic interactions and hydrogen bond by different amino acids residues. In conclusion, the results suggest that the experimental treatment triggers centrosome amplification via upregulations of expression and binding of 14-3-3σ and Hsp74.

Heat shock protein 70 is induced by pepsin via MAPK signaling in human nasal epithelial cells

BACKGROUND

Recent studies have shown that laryngopharyngeal reflux is associated with chronic rhinosinusitis. Pepsin may be a key factor involved in the injury of nasal mucosal epithelial cells, but the pathogenesis remains unclear. We are to investigate whether a mitogen-activated protein kinase (MAPK) pathway regulates heat shock protein 70 (HSP70) expression in primary cultures of human nasal epithelial cells (HNEpCs) in response to pepsin stimulation.

METHODS

HSP70 protein expression levels in HNEpCs were estimated by Western blot analysis after treatment with pepsin. MAPK pathway activity levels were also evaluated to elucidate the mechanism underlying the effects of pepsin on HSP70 in HNEpCs. Inhibitors of signaling pathways were used to determine the contribution of MAPKs in HSP70 response after pepsin stimulation. Cellular apoptosis and cell viability in HNEpCs after treatment with pepsin were measured.

RESULTS

The expression of HSP70 increased after stimulation with pepsin and decreased after the removal of pepsin. Pepsin induced activation of p38, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase (JNK) 1/2. Inhibition of JNK1/2 reduced HSP70 expression in HNEpCs. The apoptosis in HNEpCs at 12 h after treatment with pepsin at pH 7.0 increased significantly when compared with the control and pH 7.0 groups. Cell viability decreased following exposure to pepsin at pH 7.0.

CONCLUSION

Pepsin, even under neutral pH 7.0, increases the expression of HSP70 in HNEpCs by activating the JNK/MAPK signaling pathway. Increased HSP70 may be the protective mechanism when pepsin presents in the other parts of the body.

PI3K/Akt signaling pathway and Hsp70 activate in hippocampus of rats with chronic manganese sulfate exposure

Manganese (Mn) has come to the forefront of environmental concerns due to its neurotoxicity. However, the toxic effect of Mn is not fully understood. The purpose of this study is to investigate the impacts of chronic manganese sulfate (MnSO₄) exposure in regulating the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) signaling pathway in rats. In this study, rats were treated with 0, 5.0, 10.0, and 20.0 mg/kg MnSO₄•H₂O five days a week for 24 weeks via intraperitoneal injection. At the end of the exposure period, the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA), and heat shock protein (Hsp70) in rats' plasma were quantified; the mRNA expression levels of caspase-3, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), serine-threonine protein kinase (Akt-1), and forkhead box O3a (FoxO3a) were measured through real-time quantitative PCR (RT-PCR); and the levels of protein Hsp70 and Akt were assessed by western blot. With an increasing dose of MnSO₄, the organ coefficients of all tested organs were significantly increased, except the testis. Compared with the control group, the activities of plasma SOD, GSH-Px, and CAT in MnSO₄-exposed groups were significantly decreased, while the concentrations of plasma MDA and Hsp70 were significantly increased. Moreover, the hippocampal mRNA levels of Bcl-2, caspase-3, Akt-1, and FoxO3a in MnSO₄-exposed groups were downregulated, but the level of Bax was upregulated. Meanwhile, the level of phosphorylation of Akt (p-Akt) and Hsp70 proteins tends to be upregulated by increasing MnSO₄ exposure (P < 0.05). The plasma Hsp70 level was negatively associated with SOD, CAT, and GSH-Px activities (P < 0.05), and positively associated with blood MDA concentration and hippocampal Hsp70 levels (P < 0.05). Chronic MnSO₄ exposure can result in apoptosis of central nerve cells, activate the PI3K/Akt signaling pathway in rats' hippocampus, and upregulate Hsp70 transcription and translation.

Effects of proton pump inhibitors on reversing multidrug resistance via downregulating V-ATPases/PI3K/Akt/mTOR/HIF-1α signaling pathway through TSC1/2 complex and Rheb in human gastric adenocarcinoma cells in vitro and in vivo

Background

Our study aimed to explore the effects of PPIs on reversing multidrug resistance (MDR) to chemotherapy in gastric cancer by inhibiting the expression of V-ATPases and the PI3K/Akt/mTOR/HIF-1α signal pathway.

Methods

The gastric cancer cell lines SGC7901 and the multidrug resistance cell lines SGC7901/MDR were pretreated by the pantoprazole or the esomeprazole, respectively. Real-time PCR was used to determine mRNA levels, and western blotting and immunofluorescent staining analyses were employed to determine the protein expressions and intracellular distributions of the V-ATPases, PI3K, Akt, mTOR, HIF-1α, P-gp and MRP1 before and after PPIs pretreatment. SGC7901/MDR cells were planted on the athymic nude mice. Then the effects of PPZ pretreatment and/or ADR were compared by determining the tumor size, tumor weight and nude mice weight.

Results

PPIs pretreatment could inhibit mRNA levels of V-ATPases, MDR1 and MRP1, PI3K, Akt, mTOR and HIF-1α. PPIs inhibited V-ATPases and down-regulated the expressions of P-gp and MRP1. And further to block the expression of mTOR by Rapamycin could obviously inhibit the expressions of HIF-1α, P-gp and MRP1 in a dose-dependent manner. Therefore, PPIs inhibited the expressions of V-ATPases and then reversed MDR of the chemotherapy in gastric cancer by inhibiting P-gp and MRP1, and it could be speculated that the mechanism might be closely related to down-regulating the PI3K/Akt/mTOR/HIF-1α signaling pathway. Meanwhile, PPIs also could inhibit the expressions of TSC1/TSC2 complex and Rheb which might be involved into regulating the signaling pathway intermediately. The weight growth rate of the mice bearing tumor in the treatment group was lower than that of the nude mice in the normal group, while the weight growth rate of the mice in control group was significantly lower than that of the normal group and the treatment group, presenting a downward trend.

Conclusion

Therefore, PPIs inhibited the expressions of V-ATPases and then reversed MDR of the chemotherapy in gastric cancer by inhibiting P-gp and MRP1, and it could be speculated that the mechanism might be closely related to down-regulating the PI3K/Akt/mTOR/HIF-1α signaling pathway, and also to inhibiting the expressions of TSC1/TSC2 complex and Rheb which might be involved into regulating the signaling pathway intermediately.

Eosinophilic Esophagitis Clinical Manifestations and Differential Diagnosis

As a chronic inflammatory disease with eosinophilic infiltrate of the esophagus, eosinophilic esophagitis (EoE) causes a variety of gastrointestinal (GI) clinical manifestations. None of the symptoms, endoscopic features, or biopsy findings is pathognomonic of the disease, even with high degrees of esophageal eosinophilia. The pathogenesis has been explored by several studies, yet it still far from being completely understood. Evidence supports a role of allergen-driven Th2 lymphocyte mechanism, though not in every patient. This article addresses the disease's clinical manifestations, endoscopic findings, diagnosis, and differential diagnoses. In addition to the current diagnostic criteria, we summarize some recently emerging procedures that promise of enhancing more precise diagnosis and institution of early appropriate management, with consequent better quality of life and reduction of complications.

Troponins, heat shock proteins and glycogen phosphorylase BB in umbilical cord blood of complicated pregnancies

PURPOSE OF THE STUDY

Heat shock proteins (Hsp) are evolutionary conserved molecules with a chaperone role in cell survival. We hypothesized that cord blood concentrations of molecules reflecting fetal cardiac muscle insult, including Hsp, troponins cTnI and cTnT, and glycol-phosphorylase BB (GP-BB) would be elevated in pregnancies complicated by gestational diabetes (GDM) or preeclampsia (PIH) compared to healthy controls.

MATERIALS AND METHODS

Pregnant women admitted for delivery at >28 weeks were divided into four groups: healthy patients delivered vaginally (VAG), healthy patients delivered by c-section (CS), patients with PIH, and patients with GDM. Demographics, clinical characteristics, and cord blood concentrations of Hsp, troponins cTnI and cTnT, and GP-BB were compared between groups. Statistical analyses included t-test, Chi square, and Wilcoxon rank sum as appropriate.

RESULTS

cTnI concentrations were significantly higher in the PIH group compared to the GDM and VAG groups and they were higher in the CS group compared to the VAG group. Concentrations of Hsp70 were higher in the GDM group compared to the VAG and CS groups. Concentration of GP-BB was higher in the PIH group compared to the VAG group.

CONCLUSIONS

GP-BB and cTNI are the most sensitive markers for PIH-related fetal myocyte injury as is Hsp70 in pregnancies complicated by GDM.

Molecular cloning and expression analysis of five heat shock protein 70 (HSP70) family members in Lateolabrax maculatus with Vibrio harveyi infection

Heat shock proteins 70 (HSP70s) are molecular chaperones that aid in protection against environmental stress. In this study, we cloned and characterized five members of the HSP70 family (designated as HSPa1a, HSC70-1, HSC70-2, HSPa4 and HSPa14) from Lateolabrax maculatus using rapid amplification cDNA ends (RACE). Multiple sequence alignment and structural analysis revealed that all members of the HSP70 family had a conserved domain architecture, with some distinguishing features unique to each HSP70. Quantitative real-time (qPCR) analysis revealed that all members of the HSP70 family were ubiquitously and differentially expressed in all major types of tissues, including testicular tissue. This indicated that HSP70s have vital and conserved biological functions, and may also function in the development of germinal cells. The expression of mRNA of the five HSP70 family members mRNA expression was significantly increased in the head kidney, intestine and gill after Vibrio harveyi challenge, suggesting that HSP70s play an important role in the immune response.

Characterization and function analysis of Hsp60 and Hsp10 under different acute stresses in black tiger shrimp, Penaeus monodon

Heat shock proteins (Hsps) are a class of highly conserved proteins produced in virtually all living organisms from bacteria to humans. Hsp60 and Hsp10, the most important mitochondrial chaperones, participate in environmental stress responses. In this study, the full-length complementary DNAs (cDNAs) of Hsp60 (PmHsp60) and Hsp10 (PmHsp10) were cloned from Penaeus monodon. Sequence analysis showed that PmHsp60 and PmHsp10 encoded polypeptides of 578 and 102 amino acids, respectively. The expression profiles of PmHsp60 and PmHsp10 were detected in the gills and hepatopancreas of the shrimps under pH challenge, osmotic stress, and heavy metal exposure, and results suggested that PmHsp60 and PmHsp10 were involved in the responses to these stimuli. ATPase and chaperone activity assay indicated that PmHsp60 could slow down protein denaturation and that Hsp60/Hsp10 may be combined to produce a chaperone complex with effective chaperone and ATPase activities. Overall, this study provides useful information to help further understand the functional mechanisms of the environmental stress responses of Hsp60 and Hsp10 in shrimp.

Distinguishing GERD from eosinophilic oesophagitis: concepts and controversies

Over the past three decades, the detection of oesophageal mucosal eosinophils has transitioned from a biomarker of GERD to a diagnostic criterion for eosinophilic oesophagitis (EoE). In GERD, oesophageal eosinophils are considered part of the chronic inflammatory response to acid reflux, whereas the marked eosinophilia in EoE is viewed as a central feature of the immune response to ingested food and/or environmental antigen stimulation. Descriptions of a considerable subset of patients with symptomatic, endoscopic and histological findings of EoE that resolve with PPI therapy has led to confusion and controversy regarding the distinction of EoE from GERD. Study findings indicate that PPI-responsive oesophageal eosinophilia (PPI-REE) more closely resembles EoE than GERD, both from a clinical and immunological aspect. Although responsiveness to PPI therapy should not be utilized to exclude EoE, PPI therapy is effective at reducing oesophageal eosinophilia in ∼40% of patients, and PPI therapy is both a safe and practical initial step in the management of patients with oesophageal eosinophilia. Ongoing studies elucidating the mechanism behind PPI-REE will improve our understanding and management of EoE. In this Review, the mechanisms and evidence that underlie the controversy in the distinction between GERD and EoE are evaluated.

From reflux esophagitis to Barrett’s esophagus and esophageal adenocarcinoma

The occurrence of gastroesophageal reflux disease is common in the human population. Almost all cases of esophageal adenocarcinoma are derived from Barrett’s esophagus, which is a complication of esophageal adenocarcinoma precancerous lesions. Chronic exposure of the esophagus to gastroduodenal intestinal fluid is an important determinant factor in the development of Barrett’s esophagus. The replacement of normal squamous epithelium with specific columnar epithelium in the lower esophagus induced by the chronic exposure to gastroduodenal fluid could lead to intestinal metaplasia, which is closely associated with the development of esophageal adenocarcinoma. However, the exact mechanism of injury is not completely understood. Various animal models of the developmental mechanisms of disease, and theoretical and clinical effects of drug treatment have been widely used in research. Recently, animal models employed in studies on gastroesophageal reflux injury have allowed significant progress. The advantage of using animal models lies in the ability to accurately control the experimental conditions for better evaluation of results. In this article, various modeling methods are reviewed, with discussion of the major findings on the developmental mechanism of Barrett’s esophagus, which should help to develop better prevention and treatment strategies for Barrett’s esophagus.

Adaptation of HepG2 cells to silver nanoparticles-induced stress is based on the pro-proliferative and anti-apoptotic changes in gene expression

Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials due to their antibacterial properties. Owing to the recent boost in the usage of AgNPs-containing products, human exposure to AgNPs is increasing, highlighting the need for careful evaluation of AgNPs toxicity in humans. We used two cellular models, hepatic HepG2 and epithelial A549 cell lines, to study the mechanism of AgNPs-induced toxicity at the cellular level. These two cell lines differ significantly in their response to AgNPs treatment. In the case of A549 cells, a minor decrease in viability and increase in the extent of DNA breakage were observed. A markedly different response to AgNPs was observed in HepG2 cells. In short term, a massive induction of DNA breakage was observed, suggesting that the basal activity of antioxidant defence in these cells was not sufficient to effectively protect them from the nanoparticle-induced oxidative stress. After prolonged exposure, the extent of DNA breakage decreased to the level observed in the control cells proving that a successful adaptation to the new conditions had taken place. The cells that were unable to adapt must have died, as revealed by the Neutral Red assay that indicated less than half viable cells after 24-h treatment with 100 µg/ml of 20nm AgNPs. The gene expression analysis revealed that the observed adaptation was underlain by a pro-proliferative, anti-apoptotic signal leading to up-regulation of the genes promoting proliferation and inflammatory response (EGR1, FOS, JUN, HK2, IL4, MMP10, VEGFA, WISP1, CEBPB, IL8, SELPLG), genes coding the anti-apoptotic proteins (BCL2A1, CCL2) and factors involved in the response to stress (HSPB1, GADD45A). Such a selection of highly resistant population of cells should be taken into account in the case of medical applications of nanoparticles since the sustained proliferative signalling and resistance to cell death are hallmarks of cancer, acquired by the cells in the process of carcinogenesis.

p38 MAPK inhibition alleviates experimental acute pancreatitis in mice

BACKGROUND

The mitogen-activated protein kinases (MAPKs) signaling pathway is involved in inflammatory process. However, the mechanism is not clear. The present study was to investigate the role of p38 MAPK in acute pancreatitis in mice.

METHODS

Mice were divided into 4 groups: saline control; acute pancreatitis induced with repeated injections of cerulein; control plus p38 MAPK inhibitor SB203580; and acute pancreatitis plus SB203580. The pancreatic histology, pancreatic enzymes, cytokines, myeloperoxidase activity, p38 MAPK and heat shock protein (HSP) 60 and 70 were evaluated.

RESULTS

Repeated injections of cerulein resulted in acute pancreatitis in mice, accompanying with the activation of p38 MAPK and overexpression of HSP60 and HSP70 in the pancreatic tissues. Treatment with SB203580 significantly inhibited the activation of p38 MAPK, and furthermore, inhibited the expression of HSP60 and HSP70 in the pancreas, the inflammatory cytokines in the serum, and myeloperoxidase activity in the lung.

CONCLUSION

The p38 MAPK signaling pathway is involved in the regulation of inflammatory response and the expression of HSP60 and HSP70 in acute pancreatitis.

Eosinophilic esophagitis: interactions with gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) and eosinophilic esophagitis (EoE) are not mutually exclusive. The notion that GERD and EoE can be distinguished by the response to proton pump inhibitor (PPI) treatment is based on the mistaken assumption that gastric acid suppression is the only important therapeutic effect of PPIs, and therefore only GERD can respond to PPIs. We believe that a clinical or histologic response to PPIs does not rule in GERD or rule out EoE. We recommend a trial of PPI therapy for patients with symptomatic esophageal eosinophilia, even if the diagnosis of EoE seems clear-cut.

Proton pump inhibitors for eosinophilic oesophagitis

PURPOSE OF REVIEW

To review the significance and plausible mechanisms underlying 'proton pump inhibitor (PPI) responsive oesophageal eosinophilia' in eosinophilic oesophagitis (EoE).

RECENT FINDINGS

EoE is defined as an immune-mediated clinicopathologic condition characterized by oesophageal dysfunction and eosinophil-predominant inflammation. This new conceptual definition has been proposed partly due to a recently identified disease phenotype called 'PPI-responsive oesophageal eosinophilia'. Emerging data support the possibility that this condition represents a clinical response to anti-inflammatory properties of PPIs that are independent of effects on gastric acid.

SUMMARY

Currently, the diagnosis of EoE is reserved for patients with oesophageal eosinophilia and symptoms that do not respond to PPIs. This practice may not be appropriate, however, both because gastric acid suppression by PPIs might benefit EoE patients and because PPIs have anti-inflammatory properties that also might benefit EoE patients. More studies are sorely needed to understand the mechanisms underlying PPI-responsive oesophageal eosinophilia. Currently, a favourable response to PPI therapy should not be regarded as a proof of an underlying acid peptic disorder such as gastroesophageal reflux disease (GERD) nor should it preclude a diagnosis of EoE. Furthermore, it seems prudent to recommend a trial of PPI therapy for patients with oesophageal eosinophilia and symptoms, even when the diagnosis of EoE seems clear-cut.

Production of Cyr61 protein is modulated by extracellular acidification and PI3K/Akt signaling in prostate carcinoma PC-3 cells

High expression of Cyr61, an extracellular cysteine-rich heparin-binding protein, has been associated with a malignant cell phenotype and poor outcome in prostate cancers. Although Cyr61 was found by us to be overproduced in androgen-independent PC-3 cells treated with N-acetylcysteine (NAC), its significance is still unclear. We therefore aimed to determine how and why Cyr61 protein is overexpressed in NAC-treated cells. Here, we found that Cyr61 protein level markedly increased in cells treated with NAC at high cell seeding density. Silencing of Cyr61 by siRNA induced enhanced activity of caspase-3/7, upregulation of the proapototic Bok, BimL and BimS, cleavage of apoptosis hallmarkers such as Bax, PARP and caspase-3, and downregulation of antiapoptotic Bcl2, Bcl-xL and Mcl-1 proteins. NAC treatment caused a reduction of extracellular medium pH to acidic and an increase in Akt phosphorylation, after which the replacement with NAC-free medium returned them to control levels within 24h. Acid stimulation increased the levels of Cyr61 and p-Akt proteins, whereas it suppressed the induction of proapoptotic and antiapoptotic proteins. Overall, our data indicate that PC-3 cells overproduce Cyr61 protein via activation of the PI3K/Akt signaling as a part of the survival mechanisms under the conditions causing extracellular acidity and further cytotoxicity.

The PI3K/Akt signaling pathway regulates the expression of Hsp70, which critically contributes to Hsp90-chaperone function and tumor cell survival in multiple myeloma

Despite therapeutic advances multiple myeloma remains largely incurable, and novel therapeutic concepts are needed. The Hsp90-chaperone is a reasonable therapeutic target, because it maintains oncogenic signaling of multiple deregulated pathways. However, in contrast to promising preclinical results, only limited clinical efficacy has been achieved through pharmacological Hsp90 inhibition. Because Hsp70 has been described to interact functionally with the Hsp90-complex, we analyzed the suitability of Hsp72 and Hsp73 as potential additional target sites. Expression of Hsp72 and Hsp73 in myeloma cells was analyzed by immunohistochemical staining and western blotting. Short interfering RNA-mediated knockdown or pharmacological inhibition of Hsp72 and Hsp73 was performed to evaluate the role of these proteins in myeloma cell survival and for Hsp90-chaperone function. Furthermore, the role of PI3K-dependent signaling in constitutive and inducible Hsp70 expression was investigated using short interfering RNA-mediated and pharmacological PI3K inhibition. Hsp72 and Hsp73 were frequently overexpressed in multiple myeloma. Knockdown of Hsp72 and/or Hsp73 or treatment with VER-155008 induced apoptosis of myeloma cells. Hsp72/Hsp73 inhibition decreased protein levels of Hsp90-chaperone clients affecting multiple oncogenic signaling pathways, and acted synergistically with the Hsp90 inhibitor NVP-AUY922 in the induction of death of myeloma cells. Inhibition of the PI3K/Akt/GSK3β pathway with short interfering RNA or PI103 decreased expression of the heat shock transcription factor 1 and down-regulated constitutive and inducible Hsp70 expression. Treatment of myeloma cells with a combination of NVP-AUY922 and PI103 resulted in additive to synergistic cytotoxicity. In conclusion, Hsp72 and Hsp73 sustain Hsp90-chaperone function and critically contribute to the survival of myeloma cells. Translation of Hsp70 inhibition into the clinic is therefore highly desirable. Treatment with PI3K inhibitors might represent an alternative therapeutic strategy to target Hsp70.

A biphasic endothelial stress-survival mechanism regulates the cellular response to vascular endothelial growth factor A

Vascular endothelial growth factor A (VEGF-A) is an essential cytokine that regulates endothelial function and angiogenesis. VEGF-A binding to endothelial receptor tyrosine kinases such as VEGFR1 and VEGFR2 triggers cellular responses including survival, proliferation and new blood vessel sprouting. Increased levels of a soluble VEGFR1 splice variant (sFlt-1) correlate with endothelial dysfunction in pathologies such as pre-eclampsia; however the cellular mechanism(s) underlying the regulation and function of sFlt-1 are unclear. Here, we demonstrate the existence of a biphasic stress response in endothelial cells, using serum deprivation as a model of endothelial dysfunction. The early phase is characterized by a high VEGFR2:sFlt-1 ratio, which is reversed in the late phase. A functional consequence is a short-term increase in VEGF-A-stimulated intracellular signaling. In the late phase, sFlt-1 is secreted and deposited at the extracellular matrix. We hypothesized that under stress, increased endothelial sFlt-1 levels reduce VEGF-A bioavailability: VEGF-A treatment induces sFlt-1 expression at the cell surface and VEGF-A silencing inhibits sFlt-1 anchorage to the extracellular matrix. Treatment with recombinant sFlt-1 inhibits VEGF-A-stimulated in vitro angiogenesis and sFlt-1 silencing enhances this process. In this response, increased VEGFR2 levels are regulated by the phosphatidylinositol-3-kinase and PKB/Akt signaling pathways and increased sFlt-1 levels by the ERK1/2 signaling pathway. We conclude that during serum withdrawal, cellular sensing of environmental stress modulates sFlt-1 and VEGFR2 levels, regulating VEGF-A bioavailability and ensuring cell survival takes precedence over cell proliferation and migration. These findings may underpin an important mechanism contributing to endothelial dysfunction in pathological states.

Eosinophilic esophagitis after esophageal atresia: is there an association? Case presentation and literature review

Eosinophilic esophagitis (EoE) is a relatively new condition resulting in dysphagia or symptoms resembling gastroesophageal reflux disease, symptoms that also are common in patients with a history of esophageal atresia. We present 2 patients with persistent dysphagia after repair of esophageal atresia that was caused by EoE. Although the exact etiology and pathogenesis of EoE remain unclear, it is now generally accepted that it is the result of a T-helper cell 2-type immune response with a crucial role for the eosinophil-specific chemotaxis factor eotaxin 3 and eosinophils. Because there are genetic similarities between esophageal atresia and EoE, we speculate that patients with esophageal atresia are at increased risk for developing EoE.

The mechanism of MAP kinase activation under acidic condition in feline esophageal smooth muscle cells

Reflux esophagitis results from repeated exposure of the esophagus to acidic gastric juice or bile-containing duodenal contents. In Barrett's adenocarcinoma, acid increases proliferation via ERK and p38 MAPK activation. This study was focused on determination of the mechanism(s) underlying MAPKs (ERK 1/2, p38 MAPK, and JNK) activation induced by acidic medium at pH 4 in normal feline primary cultured esophageal smooth muscle cells (FESMCs). We detected ERK 1/2 and p38 MAPK phosphorylation after exposure to pH 4 or neutral media in the presence or absence of several inhibitors and quantified the MAPK levels using western blotting analysis and densitometry. Acidic medium markedly increased the phosphorylation of ERK 1/2 and p38 MAPK within 10 min. Acid-induced ERK 1/2 and p38 MAPK activation was inhibited by pertussis toxin (PTX-sensitive G(i/o) protein inhibitor), DEDA (phospholipase (PL) A(2) inhibitor), ρCMB (PLD inhibitor), GF109203X (protein kinase C (PKC) inhibitor) and D609 (phosphatidylcholine-specific PLC inhibitor). But, genistein (tyrosine kinase inhibitor), forskolin (adenylate cyclase activator) and U73122 (phosphatidylinositol-specific PLC inhibitor) had no effect on acid-induced ERK1/2 and p38 MAPK activation. These findings indicate that the activation of ERK 1/2 and p38 MAPK pathways by acidic conditions, at least in part, may be mediated by activation of the G(i/o) protein coupled receptors, PC-PLC, PLD, PLA(2), and PKC in FESMCs.

PPIs reverse multidrug resistance to chemotherapy in gastric cancer by inhibiting vacuolar H+-ATPase signal pathway

Multidrug resistance (MDR) in gastric cancer influences the effects of chemotherapy. The change in tumor microenvironment is intimately associated with multidrug resistance. Acidification and hypoxia are the two major characteristics of tumor microenvironment. The glucose metabolism in hypoxic conditions by the neoplasms leads to an intercellular pH drift towards acidity. But tumor cells can maintain intracellular to neutro-alkalinity. Vacuolar H⁺-ATPases may be involved in this process by regulating H⁺ excretion. Acidification of extracellular pH would trigger the intracellular PI3K/Akt signal pathway, activate mTOR, up-regulate the expression of HIF-1α, and promote the expression of P-gp and MRP1, resulting in multidrug resistance in gastric cancer. PPIs may change the tumor microenvironment by inhibiting the expression of vacuolar H⁺-ATPases, trigger the PI3K/Akt/mTOR/HIF-1α signal pathway and reverse multidrug resistance to chemotherapy in gastric cancer.

Inducible hsp70 in the regulation of cancer cell survival: analysis of chaperone induction, expression and activity

Understanding the mechanisms that control stress is central to realize how cells respond to environmental and physiological insults. All the more important is to reveal how tumour cells withstand their harsher growth conditions and cope with drug-induced apoptosis, since resistance to chemotherapy is the foremost complication when curing cancer. Intensive research on tumour biology over the past number of years has provided significant insights into the molecular events that occur during oncogenesis, and resistance to anti-cancer drugs has been shown to often rely on stress response and expression of inducible heat shock proteins (HSPs). However, with respect to the mechanisms guarding cancer cells against proteotoxic stresses and the modulatory effects that allow their survival, much remains to be defined. Heat shock proteins are molecules responsible for folding newly synthesized polypeptides under physiological conditions and misfolded proteins under stress, but their role in maintaining the transformed phenotype often goes beyond their conventional chaperone activity. Expression of inducible HSPs is known to correlate with limited sensitivity to apoptosis induced by diverse cytotoxic agents and dismal prognosis of several tumour types, however whether cancer cells survive because of the constitutive expression of heat shock proteins or the ability to induce them when adapting to the hostile microenvironment remains to be elucidated. Clear is that tumours appear nowadays more "addicted" to heat shock proteins than previously envisaged, and targeting HSPs represents a powerful approach and a future challenge for sensitizing tumours to therapy. This review will focus on the anti-apoptotic role of heat shock 70kDa protein (Hsp70), and how regulatory factors that control inducible Hsp70 synthesis, expression and activity may be relevant for response to stress and survival of cancer cells.

TLR2 ligand induces protection against cerebral ischemia/reperfusion injury via activation of phosphoinositide 3-kinase/Akt signaling

This study examined the effect of TLR2 activation by its specific ligand, Pam3CSK4, on cerebral ischemia/reperfusion (I/R) injury. Mice (n = 8/group) were treated with Pam3CSK4 1 h before cerebral ischemia (60 min), followed by reperfusion (24 h). Pam3CSK4 was also given to the mice (n = 8) 30 min after ischemia. Infarct size was determined by triphenyltetrazolium chloride staining. The morphology of neurons in brain sections was examined by Nissl staining. Pam3CSK4 administration significantly reduced infarct size by 55.9% (p < 0.01) compared with untreated I/R mice. Therapeutic treatment with Pam3CSK4 also significantly reduced infarct size by 55.8%. Morphologic examination showed that there was less neuronal damage in the hippocampus of Pam3CSK4-treated mice compared with untreated cerebral I/R mice. Pam3CSK4 treatment increased the levels of Hsp27, Hsp70, and Bcl2, and decreased Bax levels and NF-κB-binding activity in the brain tissues. Administration of Pam3CSK4 significantly increased the levels of phospho-Akt/Akt and phospho-GSK-3β/GSK-3β compared with untreated I/R mice. More significantly, either TLR2 deficiency or PI3K inhibition with LY29004 abolished the protection by Pam3CSK4. These data demonstrate that activation of TLR2 by its ligand prevents focal cerebral ischemic damage through a TLR2/PI3K/Akt-dependent mechanism. Of greater significance, these data indicate that therapy with a TLR2-specific agonist during cerebral ischemia is effective in reducing injury.

FLZ, a novel HSP27 and HSP70 inducer, protects SH-SY5Y cells from apoptosis caused by MPP(+)

Heat shock proteins (HSPs) play an essential role in various neurodegenerative diseases. Manipulation of upregulation of HSPs in cells has been demonstrated to provide a therapeutic strategy to counteract the misfolding and aggregation of proteins that resulted in neurodegenerative disease. Our previous studies have shown that FLZ, a synthetic novel derivative of squamosamide from a Chinese herb, had potent neuroprotective effect against several experimental Parkinson's disease (PD) models. However, the mechanism of its neuroprotective effect is still not clarified. The present study demonstrated that FLZ induced HSP27 and HSP70 proteins and mRNA expression in a time- and dose-dependent manner in SH-SY5Y cells. Further studies showed that FLZ treatment stimulated the activation of heat shock factor 1 (HSF1) and its regulatory kinase Akt. Inactivation of Akt pathway by the PI3K inhibitor LY294002 blocked the expression of HSP27 and HSP70 induced by FLZ. Moreover, the inducing effects of FLZ on HSP27, HSP70, and HSF1 were all blocked by quercetin, an inhibitor of HSP biosynthesis. The cytoprotective effect of HSP27/HSP70 induced by FLZ against MPP(+) was assessed in SH-SY5Y cells. The pretreatment of FLZ significantly induced the accumulations of HSP27/HSP70 and suppressed the apoptosis caused by MPP(+) in SH-SY5Y cells. However, the protective effects of FLZ against MPP(+) were significantly blocked by quercetin, which indicated that the cytoprotective action of FLZ against MPP(+)-induced apoptosis is at least partially mediated by its induction of HSP27/HSP70. These results provide new evidence for elucidating the mechanism of the neuroprotective effect of FLZ against PD.

Induction of HSPA4 and HSPA14 by NBS1 overexpression contributes to NBS1-induced in vitro metastatic and transformation activity

BACKGROUND

Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome associated with cancer predisposition, radiosensitivity, microcephaly, and growth retardation. The NBS gene product, NBS1 (p95) or nibrin, is a part of the MRN complex, a central player associated with double-strand break (DSB) repair. We previously demonstrated that NBS1 overexpression contributes to transformation through the activation of PI 3-kinase/Akt. NBS1 overexpression also induces epithelial-mesenchymal transition through the Snail/MMP2 pathway.

METHODS

RT-PCR, Western blot analysis, in vitro migration/invasion, soft agar colony formation, and gelatin zymography assays were performed.

RESULTS

Here we show that heat shock protein family members, A4 and A14, were induced by NBS1 overexpression. siRNA mediated knockdown of HSPA4 or HSPA14 decreased the in vitro migration, invasion, and transformation activity in H1299 cells overexpressing NBS1. However, HSPA4 or HSPA14 induced activity was not mediated through MMP2. NBS1 overexpression induced the expression of heat shock transcription factor 4b (HSF4b), which correlated with the expression of HSPA4 and HSPA14.

CONCLUSION

These results identify a novel pathway (NBS1-HSF4b-HSPA4/HSPA14 axis) to induce migration, invasion, and transformation, suggesting the activation of multiple signaling events induced by NBS1 overexpression.

Peritoneal dialysis fluid induces p38-dependent inflammation in human mesothelial cells

BACKGROUND

Noninfectious upregulation of proinflammatory pathways in mesothelial cells may represent an integral part of their stress response upon exposure to peritoneal dialysis fluids (PDF).

OBJECTIVE

The aim of this study was to evaluate the role of the stress-inducible mitogen-activated protein kinase (MAPK) p38 in regulation of inflammatory and stress responses in mesothelial cells following in vitro exposure to PDF.

MATERIALS AND METHODS

Human peritoneal mesothelial cells were exposed to Dianeal PD4 or Physioneal (Baxter AG, Vienna, Austria) containing 1.36% glucose and then allowed to recover. Phosphorylation of p38, induction of heat shock protein-70 (HSP70), release of lactate dehydrogenase (LDH), secretion of interleukin (IL)-8, gene transcription, and mRNA stability were assessed with and without the MAPK p38 inhibitor SB203580.

RESULTS

Exposure to Dianeal resulted in phosphorylation of p38 within 30 minutes (309% of control, p < 0.05) and increased IL-8 release (370% of control, p < 0.05), HSP70 expression (151% of control, p < 0.05), and LDH release (180% of control, p < 0.05). Exposure to Physioneal resulted in attenuated changes in IL-8, HSP70, and LDH. Addition of the p38 inhibitor SB203580 to Dianeal resulted in dampened IL-8 release (-55%; p < 0.05) and basal HSP70 expression, and unchanged LDH release. Effects of p38 on IL-8 were at transcriptional, posttranscriptional, and translational levels.

CONCLUSION

These data confirm concordant p38-dependent upregulation of IL-8 and HSP70 following exposure to bioincompatible PDF. The MAPK p38 pathway therefore links proinflammatory processes and the cellular stress response in human peritoneal mesothelial cells.

Altered expression of HSP27 and HSP70 in distal oesophageal mucosa in patients with gastro-oesophageal reflux disease subjected to fundoplication

BACKGROUND

Gastro-oesophageal reflux disease (GERD) is a risk factor for oesophageal adenocarcinoma. Although fundoplication cures reflux symptoms and oesophagitis, it remains controversial whether it is capable of preventing the development of oesophageal adenocarcinoma. Hsp27 and Hsp70 are associated with the development of cancer, whereas the effect of fundoplication on them is not known.

METHODS

The expression of Hsp27 and Hsp70 was assessed semiquantitatively from biopsies of oesophageal mucosa for a prospective cohort of 19 patients with GERD treated with fundoplication and 7 controls without GERD. Upper gastrointestinal endoscopy with biopsies from the oesophagogastric junction (EGJ) and the distal and proximal oesophagus were performed preoperatively (19 patients) and after recovery from GERD at 6 (19 patients) and 48 months (16 patients) postoperatively.

RESULTS

The expressions of both Hsp27 (p = 0.001) and Hsp70 (p = 0.002) in the distal oesophagus were lower in patients preoperatively and at 48 months postoperatively (p < 0.001 for both) than in controls. The patients' Hsp27 and Hsp70 levels were lower preoperatively in the proximal oesophagus (p = 0.048 for both) than in controls. Both Hsp27 (p = 0.002) and Hsp70 (p = 0.003) were lower in the distal oesophagus preoperatively and at 48 months postoperatively (p = 0.003 for Hsp27, p = 0.004 for Hsp70) than in the proximal oesophagus.

CONCLUSIONS

Our results indicate that there may be some factor interfering with the mucosal defence system of the distal oesophagus in GERD that is uninfluenced by fundoplication and not associated with the acid-reflux-normalizing effect.

Hyperthermia-induced Hsp70 and MT20 transcriptional upregulation are mediated by p38-MAPK and JNKs in Mytilus galloprovincialis (Lamarck); a pro-survival response

In the present study we investigated the signal transduction cascades triggered by acute thermal stress in Mytilus galloprovincialis gills. This particular species has been reported to exhibit a significant tolerance to high temperatures; thus, it was intriguing to examine the molecular mechanisms responsible for this extraordinary trait. In particular, exposure to 30 degrees C was found to cause a significant and sustained stimulation of p38-MAPK phosphorylation while the activation profile of JNKs was transient and relatively moderate. We also observed that hyperthermia induced apoptosis as a delayed response, with both MAPK subfamilies rapidly translocating to the nucleus. The phosphorylation of cJun, ATF2 and NFkappaB was detected next. Using selective inhibitors, phosphorylation of these transcription factors was established to be dependent on p38-MAPK or JNKs. Subsequently, potential changes in gene expression were assessed. In this context, hyperthermia resulted in the transcriptional upregulation of Hsp70 and MT20 genes with a widely known salutary effect, preserving mussel fitness and performance under adverse environmental conditions. Interestingly, p38-MAPK and JNKs were found to mediate the hyperthermia-induced Hsp70 and MT20 upregulation as well as the delayed induction of apoptosis under the interventions studied. Overall this is, to our knowledge, the first time that an insight into the compensatory survival ;programme' initiated in Mytilus galloprovincialis gills, contributing to this organism's exceptional tolerance to thermal stress, has been gained. In particular, we provide evidence demonstrating the principal role of p38-MAPK and JNKs in transducing the stress signal via mobilization of specific transcription factors and the transcriptional upregulation of cytoprotective genes.

Regulation of HSP60 and the role of MK2 in a new model of severe experimental pancreatitis

The objective of this study was to investigate the role of MAPKAP kinase 2 (MK2) and heat shock protein (HSP) HSP60 in the pathogenesis of a new model of severe acute pancreatitis (AP). MK2 plays a significant role in the regulation of cytokines. It has been shown that induction and expression of several HSPs can protect against experimental pancreatitis. Interplay between both systems seems of high interest. Mice with a homozygous deletion of the MK2 gene were used. Severe AP was induced by combined intraperitoneal injections of cerulein with lipopolysaccharide (LPS). Severity of AP was assessed by biochemical markers and histology. The serum IL-6 and lung myeloperoxidase (MPO) levels were determined for assessing the extent of systemic inflammatory response. Expression of HSP25, HSP60, HSP70, and HSP90 was analyzed by Western blotting. Repeated injections of cerulein alone or cerulein plus LPS (Cer+LPS) resulted in local inflammatory responses in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the Cer+LPS group. Compared with the C57Bl wild-type mice, the MK2-/- mice presented with significant milder pancreatitis and attenuated responses of serum amylase and trypsinogen activity. Furthermore, serum IL-6 was decreased as well as lung MPO activity. Injection of LPS alone displayed neither pancreatic inflammatory responses nor alterations of pancreatic enzyme activities but evidently elevated serum IL-6 levels and increased lung MPO activity. In contrast hereto, in the MK2-/- mice, these changes were much milder. Increased expression of HSP25 and HSP60 occurred after induction of AP. Especially, HSP60 was robustly elevated after Cer+LPS treatment, in both MK2-/- and wild-type mice. Thus the homozygous deletion of the MK2 gene ameliorates the severity of acute pancreatitis and accompanying systemic inflammatory reactions in a new model of severe acute pancreatitis. Our data support the hypothesis that MK2 participates in the multifactorial regulation of early inflammatory responses in AP, independently of the regulation of stress proteins like HSP25 and HSP60 and most likely due to its effect on cytokine regulation.

Potential anti-inflammatory effects of proton pump inhibitors: a review and discussion of the clinical implications

Proton pump inhibitors (PPIs) are potent blockers of gastric acid secretion, and are widely regarded as the agents of choice for the treatment of acid-peptic disorders. For patients with upper gastrointestinal symptoms of uncertain etiology, improvement with PPI therapy is considered prima facie evidence of a pathogenetic role for acid-peptic disease. In addition to anti-secretory effects, however, PPIs have been found to have anti-oxidant properties and direct effects on neutrophils, monocytes, endothelial, and epithelial cells that might prevent inflammation. Those anti-inflammatory effects of the PPIs might influence a variety of inflammatory disorders, both peptic and non-peptic, within and outside of the gastrointestinal tract. The purpose of this report is to review the mechanisms whereby PPIs might exert anti-inflammatory effects exclusive of gastric acid inhibition, to discuss the clinical implications of those effects, and to emphasize that a clinical response to PPIs should not be construed as proof for an underlying acid-peptic disorder.

Local application of olprinone for promotion of peripheral nerve regeneration

BACKGROUND

Olprinone was applied locally to the sciatic nerves of rats, and nerve regeneration activity was examined in relation to heat shock protein (HSP)27 expression.

METHODS

Adult rat sciatic nerves were locally exposed to olprinone, physiological saline, or a mixture of saline and HCl and underwent crush injury. HSP27 protein levels were assessed by Western blotting and immunohistochemistry. Nerve regeneration was assessed by sciatic function index (SFI) and by morphological evaluation.

RESULTS

Olprinone was detected in ipsilateral L4-L6 dorsal root ganglion (DRG) and sciatic nerve proximal to the site of crush injury. Western blot analysis of the DRG 24 h postsurgery and the sciatic nerve 7 days postsurgery showed a marked increase in HSP27 protein levels in the olprinone-treated group. Immunohistochemical analysis was consistent with the Western blot analysis. SFI was significantly better for the olprinone-treated group than for either the saline- or HCl-treated groups at 7, 22, and 25 days, respectively, after application. The packing density and the number of myelinated axons 21 days after the crush injury in the olprinone-treated group were significantly greater in comparison to the other groups.

CONCLUSION

The local application of olprinone to the sciatic nerve increases HSP27 protein levels in DRG in the early stage and in the sciatic nerve 1 week thereafter. The results from this crush model indicate that increasing levels of HSP27 appear to result in therapeutic effects.

Heat stress upregulates chaperone heat shock protein 70 and antioxidant manganese superoxide dismutase through reactive oxygen species (ROS), p38MAPK, and Akt

Chinese hamster lung fibroblasts V79 cells were treated with heat stress for 4 weeks with short duration (15 min) heat shock every alternate day in culture. It was observed that Hsp 70 and the antioxidant enzyme MnSOD became overexpressed during the chronic heat stress period. Both p38 MAPK and Akt became phosphorylated by chronic heat stress exposure. Simultaneous exposure to SB203580, a potent and specific p38MAPK inhibitor drastically inhibited the phosphorylation of p38MAPK and Akt. Furthermore, exposure to SB203580 also blocked the increase in Hsp70 and MnSOD levels and the elevated SOD activity brought about by chronic heat stress. Heat shock factor 1 (HSF1) transcriptional activity and nuclear translocation of HSF1 were prominently augmented by chronic heat stress, and this amplification is markedly reduced by concomitant exposure to SB203580. Also, activations of p38MAPK and Akt and upregulations of Hsp70 and MnSOD were observed on exposure to heat shock for a single exposure of longer duration (40 min). siRNA against p38MAPK notably reduced Akt phosphorylation by single exposure to heat stress and drastically diminished the rise in Hsp70 and MnSOD levels. Similarly, siRNA against Akt also eliminated the augmentation in Hsp70 and MnSOD levels but p38MAPK levels remained unaffected. Heat stress produced reactive oxygen species (ROS) in V79 fibroblasts. N-acetyl cysteine blocked the increase in phosphorylation of p38MAPK, amplification of Hsp70, and MnSOD levels by heat stress. Therefore, we conclude that heat stress-activated p38MAPK which in turn activated Akt. Akt acted downstream of p38MAPK to increase Hsp70 and MnSOD levels.Concise summary: Thermal injury of the skin over a long period of time has been associated with development of cancerous lesions. Also, in many cancers, the cytoprotective genes Hsp70 and MnSOD have been found to be overexpressed. Therefore, we considered it important to identify the signaling elements upstream of the upregulated survival genes in heat stress. We conclude that heat stress activated p38MAPK which in turn activated Akt. Akt mediated an augmentation in Hsp70 and MnSOD levels working downstream of p38MAPK.

Phosphoinositide 3-kinase gamma required for lipopolysaccharide-induced transepithelial neutrophil trafficking in the lung

Phosphoinositide 3-kinase gamma(PI3Kgamma) is a critical mediator of directional cell movement. Here, we sought to characterise the role of PI3Kgamma in mediating the different steps of polymorphonuclear leukocyte (PMN) trafficking in the lung. In a murine model of lipopolysaccharide (LPS)-induced lung injury, PMN migration into the different lung compartments was determined in PI3Kgamma gene-deficient (PI3Kgamma(-/-)) and wild-type mice. Bone marrow chimeras were created to characterise the role of PI3Kgamma on haematopoietic versus nonhaematopoietic cells. A small-molecule PI3Kgamma inhibitor was tested in vitro and in vivo. PMN adhesion to the pulmonary endothelium and transendothelial migration into the lung interstitium was enhanced in PI3Kgamma(-/-) mice. However, transepithelial migration into the alveolar space was reduced in these mice. When irradiated PI3Kgamma(-/-) mice were reconstituted with bone marrow from wild-type mice, migratory activity into the alveolar space was restored partially. A small-molecule PI3Kgamma inhibitor reduced chemokine-induced PMN migration in vitro when PMNs or epithelial cells, but not when endothelial cells, were treated. The inhibitor also reduced LPS-induced PMN migration in vivo. We conclude that PI3Kgamma is required for transepithelial but not for transendothelial migration in LPS-induced lung injury. Inhibition of PI3Kgamma activity may be effective at curbing excessive PMN infiltration in lung injury.