Induction of heat shock protein 70 protects intestinal epithelial IEC-18 cells from oxidant and thermal injury

Role of Heme Oxygenase in Gastrointestinal Epithelial Cells

The gastrointestinal tract is a unique organ containing both vascular and luminal routes lined by epithelial cells forming the mucosa, which play an important role in the entry of nutrients and act as a selective barrier, excluding potentially harmful agents. Mucosal surfaces establish a selective barrier between hostile external environments and the internal milieu. Heme is a major nutritional source of iron and is a pro-oxidant that causes oxidative stress. Heme oxygenases (HOs) catalyze the rate-limiting step in heme degradation, resulting in the formation of iron, carbon monoxide, and biliverdin, which are subsequently converted to bilirubin by biliverdin reductase. In gastrointestinal pathogenesis, HO-1, an inducible isoform of HO, is markedly induced in epithelial cells and plays an important role in protecting mucosal cells. Recent studies have focused on the biological effects of the products of this enzymatic reaction, which have antioxidant, anti-inflammatory, and cytoprotective functions. In this review, the essential roles of HO in the gastrointestinal tract are summarized, focusing on nutrient absorption, protection against cellular stresses, and the maintenance and regulation of tight junction proteins, emphasizing the potential therapeutic implications. The biochemical basis of the potential therapeutic implications of glutamine for HO-1 induction in gastrointestinal injury is also discussed.

Alterations of the 70 kDa heat shock protein (HSP70) and sequestosome-1 (p62) in women with breast cancer

Peripheral blood mononuclear cells (PBMCs) respond to altered physiological conditions to alleviate the threat. Production of the 70 kDa heat shock protein (HSP70) is up-regulated to protect proteins from degradation. Sequestosome-1 (p62) binds to altered proteins and the p62-protein complex is degraded by autophagy. P62 is also a regulator of intracellular kinase activity and cell differentiation. We hypothesized that the PBMC response to a malignant breast mass involves elevated production of HSP70 and a decrease in intracellular p62. In this study 46 women had their breast mass excised. PBMCs were isolated and intracellular levels of HSP70 and p62 were quantitated by ELISA. Differences between women with a benign or malignant breast mass were determined. A breast malignancy was diagnosed in 38 women (82.6%) while 8 had a benign lesion. Mean intracellular HSP70 levels were 79.3 ng/ml in PBMCs from women with a malignant lesion as opposed to 44.2 ng/ml in controls (p = 0.04). The mean PBMC p62 level was 2.3 ng/ml in women with a benign breast lesion as opposed to 0.6 ng/ml in those with breast cancer (p < 0.001). Mean p62 levels were lowest in women with invasive carcinoma and a positive lymph node biopsy when compared to those with in-situ carcinoma or absence of lymphadenopathy, respectively. Intracellular HSP70 and p62 levels in PBMCs differ between women with a malignant or benign breast lesion. These measurements may be of value in the preoperative triage of women with a breast mass.

The protective effect of selenium from heat stress-induced porcine small intestinal epithelial cell line (IPEC-J2) injury is associated with regulation expression of selenoproteins

The present study compared the protective effect of sodium selenite (SS) and selenomethionine (SeMet) on heat stress (HS)-invoked porcine IPEC-J2 cellular damage and integrate potential roles of corresponding selenoprotein. Cells were cultured at 37°C until 80 % confluence and then subjected to four different conditions for 24 h: at 37°C (control), 41·5°C (HS), 41·5°C supplied with 0·42 µmol Se/L SS (SS), or SeMet (SeMet). HS significantly decreased cell viability, up-regulated mRNA and protein levels of heat shock protein 70 (HSP70) and down-regulated mRNA and protein levels of tight junction-related proteins (claudin-1 (CLDN-1) and zonula occludens-1 (ZO-1)). HS-induced cell injury was associated with the up-regulation (P < 0·05) of six inflammation-related genes and fourteen selenoprotein encoding genes and down-regulation (P < 0·05) of two inflammation-related genes and five selenoprotein encoding genes. Compared with the HS group, SS and SeMet supplementation resulted in an increase (P < 0·05) in cell viability, decreased (P < 0·05) mRNA expression of HSP70 and six inflammation-related genes and rescue (P < 0·05) of mRNA and protein levels of CLDN-1 and ZO-1. SS and SeMet supplementation changes the expressions of nineteen selenoprotein encoding genes in cells affected by HS. Both Se supplementation significantly recovered the protein level of glutathione peroxidase-1 and increased selenoprotein P in the IPEC-J2 cells under HS, respectively. In summary, Se supplementation alleviated the negative impact of HS on IPEC-J2 cells, and their cellular protective effect was associated with regulation expression of selenoproteins, and SeMet exhibited a better protective effect.

Flavonoids protect colon against radiation induced colitis

Radiation induced colitis is one the most common clinical issue for patients receiving radiotherapy. For this reason, we aimed to investigate the effect of antioxidant-effective flavonoids hesperidin and quercetin on the intestinal damage induced by radiation in this study. TNF-alpha, interleukin-10 (IL-10), heat shock protein 70 (HSP 70) and caspase 3, 8, 9 markers of apoptotic pathways were measured in the colon tissues of irradiated acute intestinal damage by enzyme-linked immunosorbent assay (ELISA). Irradiation of rats caused a significance increase of TNF-alpha, caspase 3/8/9 and decrease of IL-10 concentrations. Hesperidin and quercetin treatment resulted in decreased levels of TNF-alpha and increased levels of IL-10. Quercetin significantly decreased caspase 3/8/9 levels. Hesperidin produced a decreased of caspase 3/8/9 levels compared with irradiation group but this was statistically not significant. Only significant alteration of HSP 70 were seen in hesperidin treated rats. Further studies are needed to elucidate the mechanism by which flavonoids induced signaling provides protection against apoptosis and inflammation.

Distinct roles of intracellular heat shock protein 70 in maintaining gastrointestinal homeostasis

The inducible heat shock protein 70 (Hsp70) is both cytoprotective and immunomodulatory, potentially accounting for its critical role in maintaining gastrointestinal homeostasis. When levels are reduced in conditions like inflammatory bowel diseases (IBD), loss of function contributes to the severity and chronicity of these diseases, although through which cell types and mechanisms remains unclear. Here, the role of Hsp70-mediated intestinal epithelial protection and immune regulation in experimental colitis was examined by using a villin promoter-driven Hsp70 transgene in the 2,4,6-trinitrobenzene sulfonic acid (TNBS) and dextran sodium sulfate (DSS) models and in IL-10/Hsp70 double knockout (IL10-/-/Hsp70-/-) mice. In addition, Hsp70-mediated IL-10 production and immune protection were investigated using a CD45RBhigh transfer model and measuring colonic and immune cell cytokine expression during colitis. We found that the epithelial-specific expression of Hsp70 transgene attenuated DSS-induced colitis in Hsp70-/- mice by protecting tight junctions (TJ) and their interaction with the TJ-associated protein ZO-1. In the TNBS colitis and CD45RBhigh model, Hsp70 carried out its intracellular anti-inflammatory function by maintaining IL-10 production. Impaired ERK phosphorylation, but not p38 or JNK phosphorylation pathways, was associated with decreased IL-10 production in Hsp70-deficient cells. Together, these actions can be leveraged in the context of cellular specificity to develop complementary strategies that can lead to reduction in mucosal injury and immune activation in colonic colitis development. NEW & NOTEWORTHY Using four different experimental colitis models, we filled an important gap in knowledge by defining essential roles of intracellular heat shock protein 70 in different cell types in maintaining intestinal integrity and immune regulation. These findings are relevant to human inflammatory bowel diseases and represent potential avenues for developing therapeutic strategies, not only to counter the destructive processes of inflammation but also to promote tissue healing and prevent complications frequently associated with chronic intestinal inflammation.

Emerging Roles for Noncanonical NF-κB Signaling in the Modulation of Inflammatory Bowel Disease Pathobiology

Crohn's disease and ulcerative colitis are common and debilitating manifestations of inflammatory bowel disease (IBD). IBD is characterized by a radical imbalance in the activation of proinflammatory and anti-inflammatory signaling pathways in the gut. These pathways are controlled by NF-κB, which is a master regulator of gene transcription. In IBD patients, NF-κB signaling is often dysregulated resulting in overzealous inflammation. NF-κB activation occurs through 2 distinct pathways, defined as either canonical or noncanonical. Canonical NF-κB pathway activation is well studied in IBD and is associated with the rapid, acute production of diverse proinflammatory mediators, such as COX-2, IL-1β, and IL-6. In contrast to the canonical pathway, the noncanonical or "alternative" NF-κB signaling cascade is tightly regulated and is responsible for the production of highly specific chemokines that tend to be associated with less acute, chronic inflammation. There is a relative paucity of literature regarding all aspects of noncanonical NF-ĸB signaling. However, it is clear that this alternative signaling pathway plays a considerable role in maintaining immune system homeostasis and likely contributes significantly to the chronic inflammation underlying IBD. Noncanonical NF-κB signaling may represent a promising new direction in the search for therapeutic targets and biomarkers associated with IBD. However, significant mechanistic insight is still required to translate the current basic science findings into effective therapeutic strategies.

Expression of Selenoprotein Genes Is Affected by Heat Stress in IPEC-J2 Cells

The aim of this study was to explore the impacts of heat stress (HS) on expressions of selenoprotein genes in IPEC-J2 cells. Cells were cultured with 5 % CO2-humidified chamber at 37 °C until the cells grew to complete confluence and then exposed to a mild hyperthermia at 41.5 °C (HS) or 37 °C (control) for another 24 h, finally harvested for total RNA or protein extraction. Real-time quantitative PCRs (qPCRs) were performed to compare gene expression of 25 selenoprotein genes, 3 tight junction-related genes, and 10 inflammation-related genes. Protein expressions of heat shock protein 70 (Hsp70) and selenoprotein X and P (SelX and SelP) were also investigated by Western blot. The results showed that HS up-regulated (P < 0.05) Hsp70 and one tight junction-related gene [zonula occludens-1 (Zo-1)] in IPEC-J2 cells. At the same time, HS up-regulated (P < 0.05) 4 selenoprotein genes (Gpx3, Dio2, Selk, Sels) and three inflammation-related genes (Il-6, Icam-1, Tgf-β) and down-regulated (P < 0.05 or as indicated) six selenoprotein genes (Gpx2, Gpx6, Txnrd1, Selh, Selm, Selx) and three inflammation-related genes (Ifn-β, Mcp-1, Tnf-α) in the cells. HS also exhibited impacts on protein expressions, which up-regulated Hsp70, down-regulated SelX, and showed no effect on SelP in IPEC-J2 cells. Our results showed that HS affected the expression of inflammation-related genes and up-regulated gene and protein expressions of Hsp70. The changes of so many selenoprotein genes expression implied a potential link between selenoprotein genes and HS. Moreover, the results provided by this IPEC-J2 model may be used to further study the interactive mechanisms between selenoprotein function and potential intestinal damage induced by HS.

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise.

Heat shock response and autophagy--cooperation and control

Protein quality control (proteostasis) depends on constant protein degradation and resynthesis, and is essential for proper homeostasis in systems from single cells to whole organisms. Cells possess several mechanisms and processes to maintain proteostasis. At one end of the spectrum, the heat shock proteins modulate protein folding and repair. At the other end, the proteasome and autophagy as well as other lysosome-dependent systems, function in the degradation of dysfunctional proteins. In this review, we examine how these systems interact to maintain proteostasis. Both the direct cellular data on heat shock control over autophagy and the time course of exercise-associated changes in humans support the model that heat shock response and autophagy are tightly linked. Studying the links between exercise stress and molecular control of proteostasis provides evidence that the heat shock response and autophagy coordinate and undergo sequential activation and downregulation, and that this is essential for proper proteostasis in eukaryotic systems.

Exercise prevents weight gain and alters the gut microbiota in a mouse model of high fat diet-induced obesity

Background

Diet-induced obesity (DIO) is a significant health concern which has been linked to structural and functional changes in the gut microbiota. Exercise (Ex) is effective in preventing obesity, but whether Ex alters the gut microbiota during development with high fat (HF) feeding is unknown.

Objective

Determine the effects of voluntary Ex on the gastrointestinal microbiota in LF-fed mice and in HF-DIO.

Methods

Male C57BL/6 littermates (5 weeks) were distributed equally into 4 groups: low fat (LF) sedentary (Sed) LF/Sed, LF/Ex, HF/Sed and HF/Ex. Mice were individually housed and LF/Ex and HF/Ex cages were equipped with a wheel and odometer to record Ex. Fecal samples were collected at baseline, 6 weeks and 12 weeks and used for bacterial DNA isolation. DNA was subjected both to quantitative PCR using primers specific to the 16S rRNA encoding genes for Bacteroidetes and Firmicutes and to sequencing for lower taxonomic identification using the Illumina MiSeq platform. Data were analyzed using a one or two-way ANOVA or Pearson correlation.

Results

HF diet resulted in significantly greater body weight and adiposity as well as decreased glucose tolerance that were prevented by voluntary Ex (p<0.05). Visualization of Unifrac distance data with principal coordinates analysis indicated clustering by both diet and Ex at week 12. Sequencing demonstrated Ex-induced changes in the percentage of major bacterial phyla at 12 weeks. A correlation between total Ex distance and the ΔCt Bacteroidetes: ΔCt Firmicutes ratio from qPCR demonstrated a significant inverse correlation (r² = 0.35, p = 0.043).

Conclusion

Ex induces a unique shift in the gut microbiota that is different from dietary effects. Microbiota changes may play a role in Ex prevention of HF-DIO.

Macrophages inhibit human osteosarcoma cell growth after activation with the bacterial cell wall derivative liposomal muramyl tripeptide in combination with interferon-γ

Background

In osteosarcoma, the presence of tumor-infiltrating macrophages positively correlates with patient survival in contrast to the negative effect of tumor-associated macrophages in patients with other tumors. Liposome-encapsulated muramyl tripeptide (L-MTP-PE) has been introduced in the treatment of osteosarcoma patients, which may enhance the potential anti-tumor activity of macrophages. Direct anti-tumor activity of human macrophages against human osteosarcoma cells has not been described so far. Hence, we assessed osteosarcoma cell growth after co-culture with human macrophages.

Methods

Monocyte-derived M1-like and M2-like macrophages were polarized with LPS + IFN-γ, L-MTP-PE +/− IFN-γ or IL-10 and incubated with osteosarcoma cells. Two days later, viable tumor cell numbers were analyzed. Antibody-dependent effects were investigated using the therapeutic anti-EGFR antibody cetuximab.

Results

M1-like macrophages inhibited osteosarcoma cell growth when activated with LPS + IFN-γ. Likewise, stimulation of M1-like macrophages with liposomal muramyl tripeptide (L-MTP-PE) inhibited tumor growth, but only when combined with IFN-γ. Addition of the tumor-reactive anti-EGFR antibody cetuximab did not further improve the anti-tumor activity of activated M1-like macrophages. The inhibition was mediated by supernatants of activated M1-like macrophages, containing TNF-α and IL-1β. However, specific blockage of these cytokines, nitric oxide or reactive oxygen species did not inhibit the anti-tumor effect, suggesting the involvement of other soluble factors released upon macrophage activation. While LPS + IFN-γ–activated M2-like macrophages had low anti-tumor activity, IL-10–polarized M2-like macrophages were able to reduce osteosarcoma cell growth in the presence of the anti-EGFR cetuximab involving antibody-dependent tumor cell phagocytosis.

Conclusion

This study demonstrates that human macrophages can be induced to exert direct anti-tumor activity against osteosarcoma cells. Our observation that the induction of macrophage anti-tumor activity by L-MTP-PE required IFN-γ may be of relevance for the optimization of L-MTP-PE therapy in osteosarcoma patients.

Effects of age and controlled oral dosing of Enterococcus faecium on epithelial properties in the piglet small intestine

Enterococcus faecium NCIMB 10415 is a licensed probiotic for piglets that has been shown to positively affect diarrhoea incidence and to act on transport properties and immunological parameters in the porcine intestine. The aim of the present study was to examine its effects on jejunal absorptive and secretory capacities around weaning. Furthermore, the possible involvement of heat shock proteins in the effects of probiotics on epithelial functions was investigated. A significant part of the probiotic was dosed orally to reduce the variability of intake of the probiotic. The piglets were randomly assigned to a control and a probiotic feeding group, the latter receiving 4.5×109 cfu/day of E. faecium directly into the mouth for 34 days starting after birth. Additionally, their feed was supplemented with the probiotic strain. Piglets were weaned at day 29 after birth. Ussing chamber studies were conducted with the mid-jejunum of piglets aged 14, 28, 31, 35 and 56 days. Changes in short-circuit current (ΔIsc) were measured after stimulation of Na+-coupled absorption with L-glutamine or glucose or with the secretagogue prostaglandin E2 (PGE2). The mRNA expression for SGLT1, CFTR and various heat shock proteins was determined. The transport properties changed significantly with age. The glucose-, L-glutamine- and PGE2-induced changes in Isc were highest at day 31 after birth. No significant differences between the feeding groups were observed. The mRNA of HSP60, HSC70, HSP70 and HSP90 was expressed in the jejunal tissues. The mRNA expression of HSC70 was higher and that of HSP60 was lower in the probiotic group. HSC70 expression increased with age. In conclusion, whereas age effects were observed on absorptive and secretory functions, controlled E. faecium dosing had no measurable effects on these functional parameters in this experimental setup. The possible role of heat shock proteins should be further evaluated.

The protective effect of VSL#3 on intestinal permeability in a rat model of alcoholic intestinal injury

Background

This study aimed to investigate the mechanism of the probiotic VSL#3 in acute alcoholic intestinal injury, and evaluate the effect of VSL#3, glutamine,VSL#3+glutamine and heat-killed VSL#3 therapy in a rat model.

Methods

Six- to eight-week-old male wild-type rats were divided into seven groups. To establish the acute alcohol liver disease model, rats received three doses of corn starch dissolved in PBS/40% alcohol administered intra-gastrically every 12 hours. Treatment groups received an intra-gastric dose of VSL#3, Glutamine, heat-killed VSL#3, or VSL#3+Glutamine 30 minutes prior to alcohol administration. The placebo group was treated with PBS prior to alcohol administration. TNFα and endotoxin in plasma was measured by ELISA and Tachypleus Ameboctye Lysate assays, and electron microscopy, Western blotting, and reverse transcription polymerase chain reaction were used to identify the mechanisms of VSL#3 in the regulation of epithelial permeability.

Results

First, compared with control group, endotoxin and TNFα in alcohol group was obviously high. At the same time, in VSL#3 group,the expression of endotoxin and TNFα obviously lower than the alcohol group. And the trends of the expression of tight junction proteins in these groups were reversed with the change of endotoxin and TNFα. Second, compared the groups of VSL#3 with glutamine,VSL#3+glutamine and heat-killed VSL#3,we found that both VSL#3 and heat-killed VSL#3, glutamine were as effective as VSL#3+glutamine in the treatment of acute alcohol liver disease, the expression of endotoxin and TNFα were lower than the alcohol group, and tight junction proteins were higher than the alcohol group whereas the expression of tight junction proteins were higher in VSL#3 + glutamine group than either agent alone, but have no significant difference.

Conclusion

We conclude that VSL#3 treatment can regulate the ecological balance of the gut microflora, preventing passage of endotoxin and other bacterial products from the gut lumen into the portal circulation and down-regulating the expression of TNFα, which could otherwise down-regulate the expression of tight junction proteins and increase epithelial permeability.

Heat shock protein 90β inhibits apoptosis of intestinal epithelial cells induced by hypoxia through stabilizing phosphorylated Akt

Intestinal epithelial cell (IEC) apoptosis induced by hypoxia compromise intestinal epithelium barrier function. Both Akt and Hsp90 have cytoprotective function. However, the specific role of Akt and Hsp90β in IEC apoptosis induced by hypoxia has not been explored. We confirmed that hypoxia-induced apoptosis was reduced by Hsp90β overexpression but enhanced by decreasing Hsp90β expression. Hsp90β overexpression enhanced BAD phosphorylation and thus reduced mitochondrial release of cytochrome C. Reducing Hsp90β expression had opposite effects. The protective effect of Hsp90β against apoptosis was negated by LY294002, an Akt inhibitor. Further study showed that Akt phosphorylation was enhanced by Hsp90β, which was not due to the activation of upstream PI3K and PDK1 but because of stabilization of pAkt via direct interaction between Hsp90β and pAkt. These results demonstrate that Hsp90β may play a significant role in protecting IECs from hypoxia-induced apoptosis via stabilizing pAkt to phosphorylate BAD and reduce cytochrome C release. [BMB Reports 2013;46(1): 47-52]

Cry1Ab treatment has no effects on viability of cultured porcine intestinal cells, but triggers Hsp70 expression

In vitro testing can contribute to reduce the risk that the use of genetically modified (GM) crops and their proteins show unintended toxic effects. Here we introduce a porcine intestinal cell culture (IPEC-J2) as appropriate in vitro model and tested the possible toxic potential of Cry1Ab protein, commonly expressed in GM-maize. For comprehensive risk assessment we used WST-1 conversion and ATP content as metabolic markers for proliferation, lactate dehydrogenase release as indicator for cells with compromised membrane and transepithelial electrical resistance as parameter indicating membrane barrier function. The results were compared to the effects of valinomycin, a potassium ionophore, known to induce cytotoxic effects in most mammalian cell types. Whereas no toxicity was observed after Cry1Ab treatment, valinomycin induced a decrease in IPEC-J2 viability. This was confirmed by dynamic monitoring of cellular responses. Additionally, two dimensional differential in-gel electrophoresis was performed. Only three proteins were differentially expressed. The functions of these proteins were associated with responses to stress. The up-regulation of heat shock protein Hsp70 was verified by Western blotting as well as by enzyme-linked immunosorbent assay and may be related to a protective function. These findings suggest that the combination of in vitro testing and proteomic analysis may serve as a promising tool for mechanism based safety assessment.

Low and medium but not high doses of green tea polyphenols ameliorated dextran sodium sulfate-induced hepatotoxicity and nephrotoxicity

Our previous study indicated that a diet containing a high dose (1%) of green tea polyphenols (GTPs) disrupted liver and kidney function via a reduction in antioxidant enzyme and heat shock protein (HSP) levels in both colitis and non-treated ICR mice. In the present study, we assessed the effects of 0.01%, 0.1%, and 1% dietary GTPs on liver and kidney physiological functioning in dextran sulfate sodium (DSS)-exposed and normal mice. GTPs at 0.01% and 0.1% significantly suppressed DSS-increased serum aspartate 2-oxoglutarate aminotransferase (AST) and alanine aminotransferase (ALT) levels. In contrast, GTPs at 1% increased kidney weight, serum creatinine levels, and thiobarbituric acid-reactive substances (TBARs) in both the kidney and the liver in normal mice, as compared with DSS-exposed mice. GTPs at 0.01% and 0.1% remarkably upregulated the expression of heme oxygenase-1 (HO-1) and heat shock protein 70 (HSP70) mRNA in the liver and kidney of mice exposed to DSS, whereas GTPs at 1% abolished it. Our results indicate that low and medium doses of GTPs have beneficial effects on DSS-induced hepatotoxicity and nephrotoxicity via upregulation of self-protective enzymes, while these effects disappeared at a high dose.

Regulatory coordination between two major intracellular homeostatic systems: heat shock response and autophagy

The eukaryotic cell depends on multitiered homeostatic systems ensuring maintenance of proteostasis, organellar integrity, function and turnover, and overall cellular viability. At the two opposite ends of the homeostatic system spectrum are heat shock response and autophagy. Here, we tested whether there are interactions between these homeostatic systems, one universally operational in all prokaryotic and eukaryotic cells, and the other one (autophagy) is limited to eukaryotes. We found that heat shock response regulates autophagy. The interaction between the two systems was demonstrated by testing the role of HSF-1, the central regulator of heat shock gene expression. Knockdown of HSF-1 increased the LC3 lipidation associated with formation of autophagosomal organelles, whereas depletion of HSF-1 potentiated both starvation- and rapamycin-induced autophagy. HSP70 expression but not expression of its ATPase mutant inhibited starvation or rapamycin-induced autophagy. We also show that exercise induces autophagy in humans. As predicted by our in vitro studies, glutamine supplementation as a conditioning stimulus prior to exercise significantly increased HSP70 protein expression and prevented the expected exercise induction of autophagy. Our data demonstrate for the first time that heat shock response, from the top of its regulatory cascade (HSF-1) down to the execution stages delivered by HSP70, controls autophagy thus connecting and coordinating the two extreme ends of the homeostatic systems in the eukaryotic cell.

Metabolites of Lactobacillus plantarum 2142 prevent oxidative stress-induced overexpression of proinflammatory cytokines in IPEC-J2 cell line

Probiotics have already proven beneficial effects in the treatment of several intestinal infections, but the underlying mechanisms how the probiotics can affect responses of porcine IPEC-J2 enterocytes to oxidative stress remained to be elucidated. The immunomodulatory effect of five bacterial strains (Lactobacillus plantarum 2142, Lactobacillus casei Shirota, Bifidobacterium animalis subsp. lactis BB-12, Bacillus amyloliquefaciens CECT 5940 and Enterococcus faecium CECT 4515) on 1 mM peroxide-triggered upregulation of interleukin (IL)-8 and tumor necrosis factor alpha (TNF-α) level was screened by q RT-PCR. Our data revealed that spent culture supernatant (SCS) of L. plantarum 2142 had significant lowering effect on IL-8 and TNF-α level with concomitant promoting activity on protective Hsp70 gene expression. According to our results, lactic acid (racemic, D: - and L: -lactic acid) and acetic acid produced by lactobacilli had no protective effect in quenching upregulation of proinflammatory cytokines. Furthermore, L. plantarum 2142-specific supernatant peptides were detected by gel electrophoresis and capillary zone electrophoresis.

Effects of zinc on epithelial barrier properties and viability in a human and a porcine intestinal cell culture model

Zinc is an essential trace element with a variety of physiological and biochemical functions. Piglets are commonly supplemented, during the weaning period, with doses of zinc above dietary requirements with positive effects on health and performance that might be attributed to anti-secretory and barrier-enhancing effects in the intestine. For a better understanding of these observations increasing zinc sulfate (ZnSO4; 0-200μM) concentrations were used in an in vitro culture model of porcine (IPEC-J2) and human (Caco-2) intestinal epithelial cells and effects on barrier function, viability, and the mRNA expression of one selected heat shock protein (Hsp) were assessed. When treated apically with zinc sulfate, the transepithelial electrical resistance (TEER) did not change significantly. In contrast, cell viability measured by lactate dehydrogenase (LDH) leakage, by ATP and by WST-1 conversion in postconfluent IPEC-J2 monolayers was affected after a 24-h treatment with 200μM ZnSO4. Caco-2 cells were more resistant to Zn. ZnSO4 did not induce any effect on viability, except when it was used at the highest concentration (200μM), and only in preconfluent cells. Furthermore, ZnSO4 induced Hsp70 mRNA expression at 200μM and was more pronounced in preconfluent cells. The observed dose-related effects of zinc are cell-line specific and depended on the differentiation status of the cells. The IPEC-J2 cell line appears to be a suitable in vitro model to characterize specific effects on porcine intestinal cells.

Particle-mediated delivery of cytokines for immunotherapy

The ability of cytokines to direct the immune response to vaccination, infection and tumors has motivated their use in therapy to augment or shape immunity. To avoid toxic side effects associated with systemic cytokine administration, several approaches have been developed using particle-encapsulated cytokines to deliver this cargo to specific cell types and tissues. Initial work used cytokine-loaded particles to deliver proinflammatory cytokines to phagocytes to enhance antimicrobial and antitumor responses. These particles have also been used to create a cytokine depot at a local site to supplement prophylactic or antitumor vaccines or injected directly into solid tumors to activate immune cells to eliminate established tumors. Finally, recent advances have revealed that paracrine delivery of cytokines directly to T cells has the potential to enhance T-cell mediated therapies. The studies reviewed here highlight the progress in the last 30 years that has established the potential of particle-mediated cytokine immunotherapy.

High-dose green tea polyphenols induce nephrotoxicity in dextran sulfate sodium-induced colitis mice by down-regulation of antioxidant enzymes and heat-shock protein expressions

Previously, we reported that oral feeding of 1% green tea polyphenols (GTPs) aggravated the dextran sulfate sodium (DSS)-induced colitis in mice. In the present study, we assessed the toxicity of 1% GTPs in several organs from normal and DSS-exposed mice. Sixty-two male ICR mice were initially divided into four groups. Non-treated group (group 1, n = 15) was given standard diet and water, GTPs (group 2, n = 15) received 1% GTPs in diet and water, DSS (group 3, n = 15) received diet and 5% DSS in water, and GTPs + DSS group (group 4, n = 17) received 1% GTPs in diet and 5% DSS in water. We found that group 4 significantly increased (P < 0.05) kidney weight, the levels of serum creatinine and thiobarbituric acid-reactive substances in both kidney and liver, as compared with those in group 3. The mRNA expression levels of antioxidant enzymes and heat-shock proteins (HSPs) in group 4 were lower than those of group 3. For instance, heme oxygenase-1 (HO-1), HSP27, and 90 mRNA in the kidney of group 4 were dramatically down-regulated as compared with those of group 3. Furthermore, 1% GTPs diet decreased the expression of HO-1, NAD(P)H:quinone oxidoreductase 1 (NQO1) and HSP90 in kidney and liver of non-treated mice. Taken together, our results indicate that high-dose GTPs diet disrupts kidney functions through the reduction of antioxidant enzymes and heat-shock protein expressions in not only colitis but also non-treated ICR mice.

Mifamurtide for the treatment of nonmetastatic osteosarcoma

INTRODUCTION

The standard treatment for osteosarcoma requires both macroscopic surgical wide resection and postoperative multi-drug chemotherapy in neoadjuvant and adjuvant settings. However, the 5-year event-free survival has remained at a plateau of 60-70% of patients with nonmetastatic osteosarcoma for more than 30 years.

AREAS COVERED

Mifamurtide (liposomal muramyl tripeptide phosphatidylethanolamine; L-MTP-PE) is a new agent. L-MTP-PE is a nonspecific immunomodulator, which is a synthetic analog of a component of bacterial cell walls. L-MTP-PE activates macrophages and monocytes as a potent activator of immune response in addition to standard chemotherapy. It also improves the overall survival from 70 to 78% and results in a one-third reduction in the risk of death from osteosarcoma. This review summarizes the most recent findings about L-MTP-PE and its therapeutic application for nonmetastatic osteosarcoma.

EXPERT OPINION

Recently, L-MTP-PE has been approved in Europe for the treatment of nonmetastatic osteosarcoma with chemotherapy. L-MTP-PE in combination with traditional treatment is expected to go mainstream and to be beneficial for patients with osteosarcoma. Information about potential benefit regarding mifamurtide use in the neoadjuvant setting (i.e., before surgery) and/or usefulness of L-MTP-PE in metastatic in relapsed and metastatic osteosarcoma requires analysis of expanded access and/or future clinical trials of L-MTP-PE in high-burden and low-burden situations.

Mild thermotolerance induced at 40°C protects HeLa cells against activation of death receptor-mediated apoptosis by hydrogen peroxide

Preexposure to mild temperatures such as 40°C induces thermotolerance, whereby cells resist subsequent exposure to a toxic insult. This study investigates the protective effect of mild thermotolerance (3h, 40°C) against activation of death receptor-mediated apoptosis by H(2)O(2) in HeLa cells. H(2)O(2) (5-50μM) caused rapid activation (1-3h) of the Fas death receptor pathway of apoptosis, which was evident by up-regulation of the death ligand FasL and recruitment of the adaptor protein Fas-associated death domain to the plasma membrane. This resulted in activation of caspase-8 and caspase-2, which led to activation of the cross-talk pathway involving Bid cleavage, t-Bid translocation to mitochondria, and caspase-9 activation. These changes were all diminished in thermotolerant cells. Mild thermotolerance also protected cells against cytotoxicity from H(2)O(2) as well as execution-phase events of apoptosis such as caspase-3 activation and chromatin condensation. The antioxidant polyethylene glycol-catalase abolished FasL induction and caspase-8 activation due to H(2)O(2). FasL up-regulation; activation of caspases-8, -2, -9, and -3; and chromatin condensation were decreased by the p53 inhibitor pifithrin-α, implicating p53 as an upstream factor in the activation of death receptor-mediated apoptosis by H(2)O(2). This study advances knowledge about the protective effect of adaptive responses induced by mild stresses, such as fever temperatures, against induction of apoptosis by oxidative stress.

Pre-treatment with glutamine attenuates lung injury in rats subjected to intestinal ischaemia-reperfusion

BACKGROUND

Glutamine (Gln) is the most abundant amino acid in blood and tissue fluids and is considered to be essential in certain catabolic conditions. A series of studies has shown that glutamine can attenuate cytokine release, reduce organ damage and improve survival in a rat model of endotoxaemia. The hypothesis for this rat model study is that pre-treatment with Gln reduces the expression of ICAM-1 and attenuates lung injury induced by intestinal ischaemia-reperfusion (I/R).

METHODS

Sprague-Dawley rats were randomised into five groups, namely sham group (sham surgery), Gln groups (three different doses) and control group. Lung injury caused by intestinal I/R was evaluated using Evans blue dye concentration and histopathologic examination. The level of myeloperoxidase (MPO) was measured using biochemistry method. The expression of heat shock protein 70 (HSP 70) and ICAM-1 were detected using Western blot and real-time polymerase chain reaction (PCR) methods, respectively.

RESULTS

Compared with the control group, rats pre-treated with Gln before intestinal I/R demonstrated decreased Evans Blue content and MPO activities in lung tissue, reduced the expression of ICAM-1, attenuated lung injury evidenced by pathological change compared with lactated Ringer pre-treated rats. Gln administration increased HSP 70 mRNA and protein expression in lung tissue compared with control group.

CONCLUSION

Ischaemia-reperfusion injury increases the expression of ICAM-1 in the lung. This may contribute to the migration, accumulation and activation of neutrophils. Pre-treatment with Gln attenuates rat lung injury and reduces ICAM-1 expression.

From the gut to the peripheral tissues: the multiple effects of butyrate

Butyrate is a natural substance present in biological liquids and tissues. The present paper aims to give an update on the biological role of butyrate in mammals, when it is naturally produced by the gastrointestinal microbiota or orally ingested as a feed additive. Recent data concerning butyrate production delivery as well as absorption by the colonocytes are reported. Butyrate cannot be detected in the peripheral blood, which indicates fast metabolism in the gut wall and/or in the liver. In physiological conditions, the increase in performance in animals could be explained by the increased nutrient digestibility, the stimulation of the digestive enzyme secretions, a modification of intestinal luminal microbiota and an improvement of the epithelial integrity and defence systems. In the digestive tract, butyrate can act directly (upper gastrointestinal tract or hindgut) or indirectly (small intestine) on tissue development and repair. Direct trophic effects have been demonstrated mainly by cell proliferation studies, indicating a faster renewal of necrotic areas. Indirect actions of butyrate are believed to involve the hormono-neuro-immuno system. Butyrate has also been implicated in down-regulation of bacteria virulence, both by direct effects on virulence gene expression and by acting on cell proliferation of the host cells. In animal production, butyrate is a helpful feed additive, especially when ingested soon after birth, as it enhances performance and controls gut health disorders caused by bacterial pathogens. Such effects could be considered for new applications in human nutrition.

The modulation of protein kinase A and heat shock protein 70 is involved in the reversible increase of blood-brain tumor barrier permeability induced by papaverine

Intra-arterial administration of papaverine has been revealed to cause an increase in the blood-brain tumor barrier (BTB) permeability. The exact mechanism of papaverine opening the BTB in chemotherapy of malignant cerebral tumors, however, has not been well described. We used a rat brain glioma (C6) model for studying how papaverine modulates the permeability of BTB by monitoring the activities of the tight junction (TJ)-associated protein occludin, claudin-5 and cytoskeletal protein filamentous actin (F-actin) and whether protein kinase A (PKA) and heat shock protein 70 (HSP70) were involved in the regulation of this biological process. The levels of occludin, claudin-5 and F-actin protein in the tumor tissues were down-regulated by papaverine via immunohistochemistry, immunofluorescence assays and Western blot, corresponding to the time-dependent change of the BTB permeability. The most obvious attenuation of occludin, claudin-5 and F-actin protein was observed at 1h after papaverine perfusion, companied by a significant decrease in expression levels of PKA protein. The expression level of HSP70 in the tumor tissues was also progressively increased after papaverine perfusion and reached the maximum at 3h. The results demonstrate that the reversible openning of BTB mediated by papaverine may be associated with the functional combination between PKA and HSP70. That is, BTB opening may be attributable to the down-regulation of occludin, claudin-5 and F-actin, and cAMP/PKA signaling pathway might be involved in this process. HSP70 is likely responsible for the BTB closing, which helping the repairment of injured TJ protein and the rebuilding of the BTB.

HSP70 protects intestinal epithelial cells from hypoxia/reoxygenation injury via a mechanism that involves the mitochondrial pathways

Though recent studies have reported the importance of several endogenous cytoprotective factors including heat shock protein 70 (HSP70) that protect intestinal epithelial cells (IECs) from the effects of stress and injury, the exact mechanism of HSP70 underlying cytoprotection against hypoxia/reoxygenation induced IEC injury remains unclear. The present study was designed to investigate the possible mechanisms by which HSP70 protected IECs against hypoxia/reoxygenation injury and focused on the effects of HSP70 on IEC apoptosis induced by hypoxia/reoxygenation injury. Recombinant adenoviruses (Ad-HSP70) were transfected into the intestinal epithelial cell line in vitro and then suffered from 90 min of hypoxia followed by 60 min of reoxygenation. The LDH leaking, apoptosis, and mitochondrial membrane potential (Psi(m)) were evaluated after hypoxia/reoxygenation. The expression of HSP70, cytochrome c and Bcl-2 protein was determined by Western blot or immunofluorescence analysis. The results show that HSP70 protein was highly expressed in the IECs at 48h following Ad-HSP70 transfection. HSP70 overexpression could reduce LDH leakage and cell apoptosis in IECs following hypoxia/reoxygenation injury. Furthermore, the overexpression of HSP70 significantly reversed the decrease of mitochondrial membrane potential and the release of mitochondrial cytochrome c in IECs during hypoxia/reoxygenation. HSP70 overexpression was also associated with the increasing expression of Bcl-2 protein in IECs during hypoxia/reoxygenation. We conclude that HSP70 protects IECs against hypoxia/reoxygenation induced apoptosis through increasing Bcl-2 expression, which in turn could inhibit the mitochondria-related apoptotic pathway that involves the disruption of the Psi(m) and release of cytochrome c from mitochondria.

How bacteria-induced apoptosis of intestinal epithelial cells contributes to mucosal inflammation

The life cycle of an intestinal epithelial cell is terminated by apoptosis and/or cell shedding. Apoptotic deletion of epithelial cells from the intact intestinal mucosa is not accompanied by detectable inflammatory response or loss of barrier function. But increased permeability of the epithelial barrier and increased apoptotic rates of epithelial cells have been reported for patients suffering from inflammatory bowel disease. Microbiota can both induce or inhibit apoptosis of intestinal epithelial cells thus contribute to mucosal inflammation or support epithelial integrity respectively. Bacteria-mediated cytokine secretion and altered cell signalling are central to epithelial injury. Tumor necrosis factor (TNF) secreted after exposure to invasive bacteria induces both apoptosis and cell shedding. TNF is the major target gene of the transcription factor nuclear factor-kappa B with both pro- and anti-apoptotic effects. Autophagy promotes both cell survival and “autophagic” cell death. If autophagy is directed against microbes it is termed xenophagy. Inhibition of xenophagy has been shown to decrease cell survival. Endoplasmic reticulum (ER) stress causes misfolded proteins to accumulate in the ER lumen. It was suggested that ER stress and autophagy may interact within intestinal epithelial cells. Apoptosis in response to infection may be well proposed by the host to delete infected epithelial cells or could be a strategy of microbial pathogens to escape from exhausted cells to invade deeper mucosal layers for a prolonged bacterial colonization.

LPS-induced cytokine levels are repressed by elevated expression of HSP70 in rats: possible role of NF-kappaB

Heat shock protein (HSP)70 provides a spectrum of protection against any of a variety of stresses, preventing damage measured at the level of molecules, cells, as well as whole organism. We have previously reported that lipopolysaccharide (LPS)-induced lethality in rats is prevented by a previous exposure to a mild thermal stress and that a thermal stress sufficient to induce HSP70 expression in the liver is accompanied by an inhibition of endotoxin-mediated cytokines and modulation of febrile response. However, the effect of HSP70 upregulation on cytokine expression in animals is unknown. The aim of the present study was to demonstrate the effect of HSP70 overexpression with adenovirus administration on LPS-induced increase in cytokines levels in animals. In the present study, Sprague-Dawley rats were infected with either the control AdTrack or Ad70 virus that directs the expression of human HSP70. After a 5-day incubation, animals were injected with either saline alone or LPS (50 microg/kg). Four hours later, blood samples were drawn and plasma levels of interleukin (IL)-6 or tumor necrosis factor (TNF)-alpha were measured by enzyme-linked immunosorbent assay. Our data demonstrate for the first time that HSP70 overexpression with adenovirus injection prevented the LPS-induced increase in TNF-alpha and IL-6 levels in rats. Repression of LPS-induced cytokines expressions by HSP70 upregulation was associated with inhibited IkappaBalpha degradation and nuclear factor kappa-B (NF-kappaB) p65 nuclear translocation in liver, suggesting that HSP70 overexpression may regulate LPS-induced cytokines expression through NF-kappaB pathway. We conclude that the effects of heat stress-induced increase in HSP70 protein expression on LPS-induced cytokine elaboration in whole animals can be reproduced by the actions of a single gene product.

Acrolein induces Hsp72 via both PKCδ/JNK and calcium signaling pathways in human umbilical vein endothelial cells

Acrolein is a highly electrophilic alpha,beta-unsaturated aldehydes to which humans are exposed in a variety of environment situations and is also a product of lipid peroxidation. Increased levels of unsaturated aldehydes play an important role in the pathogenesis of a number of human diseases such as Alzheimer's disease, atherosclerosis and diabetes. A number of studies have reported that acrolein evokes downstream signaling via an elevation in cellular oxidative stress. Here, we report that low concentrations of acrolein induce Hsp72 in human umbilical vein endothelial cells (HUVEC) and that both the PKCdelta/JNK pathway and calcium pathway were involved in the induction. The findings confirm that the production of reactive oxygen species (ROS) is not directly involved in the pathway. The induction of Hsp72 was not observed in other cells such as smooth muscle cells (SMC) or COS-1 cells. The results suggest that HUVEC have a unique defense system against cell damage by acrolein in which Hsp72 is induced via activation of both the PKCd/JNK and the calcium pathway.

Nuclear factor-kappa B in intestinal protection and destruction

PURPOSE OF REVIEW

Nuclear factor-kappa B (NF-kappaB) is a key transcriptional regulator of innate and adaptive immunity. This review highlights new insights into the functions of NF-kappaB in normal homeostasis and specific disease processes in the intestinal tract.

RECENT FINDINGS

Inflammatory bowel disease and experimental intestinal inflammation are characterized by NF-kappaB activation and increased expression of proinflammatory NF-kappaB target genes. Accordingly, NF-kappaB inhibition protects against chronic intestinal inflammation and necrotizing enterocolitis in animal models. However, recent findings suggest that NF-kappaB has not only proinflammatory but also tissue-protective functions. Thus, genetic ablation of the regulatory subunit, IkappaB kinase (IKK)gamma, of the central kinase complex required for NF-kappaB activation, IKK, or of both kinase subunits, IKKalpha and IKKbeta, in intestinal epithelial cells causes spontaneous murine colitis. Pharmacological inhibition of IKKbeta, and loss of IKKbeta or NF-kappaB p65 in the epithelium, sensitizes mice to acute inflammatory and injurious challenges. Deficiency in Toll-like receptor 5, a strong activator of NF-kappaB, results in spontaneous colitis and exacerbates mucosal inflammatory responses to Salmonella infection. Conversely, Toll-like receptor 5 stimulation confers radioprotection in the intestine.

SUMMARY

NF-kappaB has multiple, often opposing functions in the intestine. Antiapoptotic actions of NF-kappaB in intestinal epithelial cells dominate tissue responses to many acute inflammatory and injurious challenges, whereas proinflammatory and cell survival functions of NF-kappaB in macrophages and T cells govern chronic intestinal inflammation.

Glutamine increases autophagy under Basal and stressed conditions in intestinal epithelial cells

BACKGROUND & AIMS

Glutamine plays a protective role in intestinal cells during physiologic stress; however, the protection mechanisms are not fully understood. Autophagy functions in bulk degradation of cellular components, but has been recognized recently as an important mechanism for cell survival under conditions of stress. We therefore sought to see if glutamine's actions involve the induction of autophagy in intestinal cells and, if so, the mechanisms that underlie this action.

METHODS

Formation of microtubule-associated protein light chain 3 (LC3)-phospholipid conjugates (LC3-II) in rat intestinal epithelial IEC-18 cells and human colonic epithelial Caco-2(BBE) cells was determined by Western blotting and localized by confocal microscopy. Activation of mammalian target of rapamycin (mTOR) pathway, mitogen-activated protein (MAP) kinases, caspase-3, and poly (ADP-ribose) polymerase were monitored by Western blotting.

RESULTS

Glutamine increased LC3-II as well as the number of autophagosomes. Glutamine-induced LC3-II formation was paralleled by inactivation of mTOR and p38 MAP kinase pathways, and inhibition of mTOR and p38 MAP kinase allowed LC3-II induction in glutamine-deprived cells. Under glutamine starvation, LC3-II recovery after heat stress or the increase under oxidative stress was blunted significantly. Glutamine depletion increased caspase-3 and poly (ADP-ribose) polymerase activity after heat stress, which was inhibited by treatment with inhibitors of mTOR and p38 MAP kinase.

CONCLUSIONS

Glutamine induces autophagy under basal and stressed conditions, and prevents apoptosis under heat stress through its regulation of the mTOR and p38 MAP kinase pathways. We propose that glutamine contributes to cell survival during physiologic stress by induction of autophagy.

Lack of cross-tolerance following heat and cadmium exposure in functional MDCK monolayers

Exposure of monolayers of Madin-Darby canine kidney epithelial (MDCK) cells to a mild heat stimulus induces a state of physiological thermotolerance in which epithelial barrier function is maintained following a second more severe heat stress. We have previously shown that expression of exogenous HSP70 fully mimics the effects of the conditioning heat stress. Exposure of MDCK cells to elevated temperatures or medium containing CdCl2 caused a robust increase in cellular levels of HSP70. Pretreatment of MDCK monolayers with cadmium but not heat caused a small protection of epithelial barrier function against a second challenge with cadmium. In addition, a prior exposure of monolayers to cadmium at levels sufficient to induce HSP70 expression and increased cellular chaperone activity did not afford protection against a subsequent thermal challenge. Therefore multiple stress-specific cellular pathways impinge on the ability of heat shock proteins to induce physiological thermotolerance. Occludin, a component of tight junctions, is induced in MDCK cells engineered to express high levels of exogenous HSP70, potentially accounting for an elevation in baseline resistance. However neither basal levels of occludin, nor alterations in occludin expression, were correlated with epithelial barrier function in MDCK cells either exposed to elevated temperatures or challenged with cadmium.

Inducible heat shock protein 70 prevents multifocal flat dysplastic lesions and invasive tumors in an inflammatory model of colon cancer

BACKGROUND

Heat shock protein 70 (Hsp70) regulates protein biosynthesis and refolding of denatured proteins. Since Hsp70 participates in recovery from stress injury, we examined the effect of Hsp70 genetic deletion in the azoxymethane (AOM)/dextran sulfate sodium (DSS) model of inflammation and colon cancer.

METHODS

Hsp70 mutant mice (Hsp70.1(-/-)/70.3(-/-)) and wild-type (WT) littermates received AOM and three cycles of DSS and were killed 24 weeks later. Tumors were graded for histology and immunostained for p53, adenomatous polyposis coli, beta-catenin, cyclooxygenase-2 (Cox-2) and inducible nitric oxide synthase (iNOS) and sequenced for p53 mutations.

RESULTS

Elevated adenomas developed in 4/10 WT mice with no dysplasia in adjacent mucosa. In contrast, 7/8 Hsp70 knock out (KO) mice developed chronic mucosal inflammation and multifocal areas of flat dysplasia and 4/8 progressed to invasive carcinomas arising in a background of flat dysplastic mucosa. These differences in the incidence of flat dysplasia and invasive cancers were significant (P < 0.05). Nuclear p53 was stronger in Hsp70 KO tumors compared with WT tumors, and sequencing confirmed p53 mutations in 2/5 tumors from Hsp70(-/-) versus 0/5 in WT mice. In Hsp70 WT tumors, beta-catenin was predominantly nuclear, compared with membranous beta-catenin in Hsp70(-/-) tumors, suggesting that Hsp70 regulates beta-catenin in colonic tumorigenesis. Cox-2 and iNOS levels were increased in tumors from Hsp70(-/-) mice compared with Hsp70 WT tumors.

CONCLUSIONS

Hsp70-deleted mice treated with AOM/DSS develop flat invasive colonic tumors that mimic many histological and molecular features of ulcerative colitis colon cancer. This model will be useful to dissect the role of Hsp70 in inflammatory bowel disease colon cancer.

Liposomal muramyl tripeptide phosphatidyl ethanolamine: a safe and effective agent against osteosarcoma pulmonary metastases

Osteosarcoma is the most common form of primary malignant bone tumor. The use of chemotherapy drugs with many side effects, including high-dose methotrexate, doxorubicin, cisplatin and ifosfamide, has greatly improved osteosarcoma survival compared with surgery alone. However, for 20 years, overall survival remained at a plateau of 60-70% in nonmetastatic disease and 20-30% in metastatic osteosarcoma owing to lung metastases. Liposomal muramyl tripeptide phosphatidyl ethanolamine (L-MTP-PE) is a new agent that improves overall osteosarcoma survival (chemotherapy without L-MTP-PE 70% versus with L-MTP-PE 78%; p = 0.03). L-MTP-PE offers additional benefit for osteosarcoma treatment in combination with chemotherapy, particularly ifosfamide-containing regimens. Clinical experience indicates that side effects such as fever are temporary and controlled or prevented with ibuprofen and/or acetoaminophen premedication; severe side effects are rare. Although surgery will remain the main approach for osteosarcoma treatment of lung metastases, L-MTP-PE combined with other modalities, including chemotherapy, appears to be of benefit in these patients as well.

Antioxidative properties of human milk and spermine are not related to expression of Hsp 70

AIM

Heat shock proteins (Hsps) have been detected in various tissues, including those in the intestines, and play a role in cellular protection. Polyamines, such as spermine (SPM), are found in human milk (HM) and act as antioxidants. We hypothesized that the antioxidative property of SPM is related to the expression of Hsp and examined this relationship in an intestinal epithelial cell (IEC) line.

METHOD

(i) Confluent IEC-6 cells were exposed to mild heat shock (43 degrees C, 1 h) and then allowed to recover at 37 degrees C for 24 h. Hydrogen peroxide (H(2)O(2)) was applied to induce oxidative stress and cell viability was evaluated. (ii) Cells were exposed to mild heat shock or pre-incubated with HM or pre-incubated with 5 microM SPM for 24 h. Hsp70 expression in IEC-6 cells was analysed by Western blot.

RESULTS

The survival rate of cells treated with mild heat shock after H(2)O(2) challenge was significantly higher than that of non-pretreated cells. Western blot analysis demonstrated that Hsp70 was expressed in IEC-6 cells treated with mild heat shock but not in IEC-6 cells pre-incubated with HM or 5 microM SPM.

CONCLUSION

Mild heat shock treatment induces Hsp70, which acts as an antioxidant in IEC-6 cells, but HM or SPM does not induce Hsp70 in this system.

Translational inhibition of colonic epithelial heat shock proteins by IFN-gamma and TNF-alpha in intestinal inflammation

BACKGROUND & AIMS

Inducible heat shock proteins (iHsp), Hsp25/27 and Hsp70, play essential roles in protecting cells against stress and, in intestinal mucosal inflammation, potentially lessening the extent and severity of injury. We examined the expression and regulation of iHsp in human and experimental inflammatory bowel diseases (IBD) and in vitro.

METHODS

iHsp expression and regulation were assessed in normal and IBD colonic biopsy specimens, IL-10(-/-) mice, and young adult mouse colonic epithelial cells by immunohistochemistry, Western blot, and real-time polymerase chain reaction (PCR). Phosphorylation of double-stranded RNA-dependent protein kinase (PKR) and eukaryotic initiation factor-2alpha (eIF-2alpha) was determined by Western blot.

RESULTS

Hsp25/27 and Hsp70 levels were selectively reduced in areas of active mucosal inflammation associated with human IBD and IL-10(-/-) mice with colitis. Wild-type mice treated in vivo with interferon (IFN)-gamma + tumor necrosis factor (TNF)-alpha also demonstrated reduced colonic Hsp25/27 and Hsp70. In young adult mouse colonic epithelial cells, IFN-gamma+TNF-alpha inhibited heat induction of Hsp25/27 and Hsp70, an effect not associated with changes in iHsp messenger RNA or protein half-lives but caused by suppressed de novo iHsp synthesis. IFN-gamma+TNF-alpha cotreatment activated PKR, resulting in phosphorylation and inactivation of eIF-2alpha, an essential factor in protein translation. These effects were not due to induced apoptosis and could be negated by PKR-inhibitor and short interfering RNA to PKR. Increased phosphorylation of PKR and eIF-2alpha were also observed in active IBD tissues.

CONCLUSIONS

Mucosal inflammation is associated with iHsp down-regulation, an effect that appears mediated by translational down-regulation by proinflammatory cytokines. In the context of IBD, we propose that this mechanism contributes to the severity, extent, and persistence of inflammation-induced mucosal injury.

Induction of heat shock protein 70 by sodium arsenite attenuates burn-induced intestinal injury in severe burned rats

The present study was designed to assess the effects of induced heat shock protein 70 (HSP70) on intestinal injury after severe burn. Wistar rats were randomly divided into four groups: control group, burn group (B group), sodium arsenite pretreatment group (SA group), and sodium arsenite+quercetin pretreatment group (SA+Qu group). Plasma endotoxin and d-lactic acid content were determined at 3, 6, 12, 24, and 48h after severe burn. Samples of small intestine were obtained for histologic assessment of intestinal mucosal injury and the expression of HSP70 was assayed by Western blot. Apoptosis of the intestinal epithelial cells was examined by the TUNEL method. Results showed that SA pretreatment significantly increased expression of HSP70 in the small intestine. SA pretreatment attenuated the burn-induced increase in plasma endotoxin and d-lactic acid content, intestinal injury scores and the percentage of apoptotic intestinal epithelial cells. Co-administration of quercetin with SA abolished the SA-induced HSP70 over-expression and the beneficial effects of SA. Our findings suggest increasing expression of HSP70 induced by SA pretreatment attenuates burn-induced intestinal injury apparently by preventing apoptosis.

Heat shock protein gene 70-2 polymorphism is differentially associated with the clinical phenotypes of ulcerative colitis and Crohn's disease

BACKGROUND AND AIM

A single nucleotide polymorphism in heat shock protein 70-2 (HSP70-2) has been shown to be associated with a severe clinical course in Crohn's disease (CD), but it is not known if such a relationship exists in ulcerative colitis (UC). The aim of the present study was to identify associations between the HSP70-2 polymorphism and the clinical courses of CD and UC in Koreans.

METHODS

Restriction fragment length polymorphism analysis was performed for HSP70-2 polymorphisms using the PstI-cleavage site present in the B allele but not in the A allele of the DNA obtained from 101 patients with CD, 144 patients with UC, and 245 age- and sex-matched healthy controls. Study subjects were classified by disease behavior, severity and extent of disease.

RESULTS

In CD, multivariate analysis showed that the AA genotype of HSP70-2 polymorphisms was associated with non-perforating disease (OR 10.10, 95% CI 1.66-15.38) and male sex (OR 3.56, 95% CI 1.04-12.23), and that the BB genotype was associated with severe CD (OR 12.03, 95% CI 1.60-101.56). In contrast, multivariate analysis for UC showed that the AA genotype was associated with severe UC (OR 2.02, 95% CI 1.34-3.03).

CONCLUSIONS

CD patients with BB genotype of HSP70-2 polymorphism tend to experience a more severe clinical course and allele A is associated with more severe UC. HSP70-2 polymorphism may be used to predict CD and UC phenotypes, which can illuminate immunological differences in CD and UC.

Liposome-based drug delivery to alveolar macrophages

The recent development of liposomal formulations compatible with aerosol delivery has expanded the potential to utilise chemotherapeutic agents directly targeted to the lungs more effectively. These are agents that would otherwise not be used because of their low solubility or toxicity. Various properties of liposomal carriers, including size, surface charge, composition and the presence of ligands, alter their efficacy and specificity towards alveolar macrophages to a great extent. This editorial summarises the advances in liposome-based drug delivery to alveolar macrophages.

Induction of physiological thermotolerance in MDCK monolayers: contribution of heat shock protein 70

Enhanced survival of both individual cells and whole organisms following a heat stress is termed thermotolerance. In organisms, the maintenance of tissue function rather than the survival of individual cells ultimately determines outcome following thermal challenge. We used MDCK kidney epithelial cells to compare alterations in chaperone activity (as a measure of cellular tolerance) and epithelial barrier function (as a measure of physiological tolerance) after thermal challenge. Quercetin, an inhibitor of heat shock factor-dependent transcriptional activity, both potentiated the effects of heat on naive monolayers and blocked conditioning of monolayers following moderate heat shock, suggesting a central role of heat shock protein (HSP) family members in the maintenance of epithelial integrity. We used MDCK cells that constitutively overexpressed HSP70 to demonstrate 2 functionally distinct components of the response of monolayers to thermal stress. The maintenance of epithelial barrier function during exposure to elevated temperatures is regulated by a complex network of processes that involve the actions of HSP70 but that are independent of alterations in chaperone activity as reflected by changes in the thermal inactivation/refolding of luciferase. In contrast, the restoration of barrier function following a heat stress is directly modulated by HSP70 in a manner that can be fully accounted for by changes in chaperone activity. This study demonstrates an important, albeit complex, protective role for heat shock proteins in the modulation of MDCK epithelial barrier function following a thermal stress.

Polaprezinc protects human colon cells from oxidative injury induced by hydrogen peroxide: Relevant to cytoprotective heat shock proteins

AIM: To investigate the effect of polaprezinc on cellular damage induced by hydrogen peroxide (H₂O₂) in human colon CaCo2 cells.

METHODS: CaCo2 cells were treated with polaprezinc (10-100 μmol/L) for 6 h. After polaprezinc treatment, the cells were incubated with H₂O₂ (20 μmol/L) for 1 h. Cell viability was measured by MTT assay. Western blot analysis for heat shock protein (HSP) 27 and HSP72 in the cells was performed. Moreover, cells were pretreated with quercetin (200 μmol/L), an inhibitor of HSP synthesis, 2 h before polaprezinc treatment, and cell viability and the expression of HSP27 and 72 were assessed in these cells.

RESULTS: Polaprezinc significantly protected CaCo2 cells from cell damage induced by H₂O₂, and up-regulated the expressions of HSP27 and HSP72 in the cells (10, 30 and 100 μmol/L of polaprezinc; 35.0% ± 7.7%, 58.3% ± 14.6% and 64.2% ± 8.2%, respectively. P < 0.01 versus polaprezinc-nontreated cells; 6.0% ± 4.4%). Quercetin inhibited the up-regulation of HSP27 and HSP72 by polaprezinc and diminished the protective effect of polaprezinc against H₂O₂-caused injury in the cells.

CONCLUSION: Polaprezinc is a useful therapeutic agent for treatment of colitis and its effects depend on the function of cytoprotective HSP in colon.

Liposomal muramyl tripeptide phosphatidyl ethanolamine: ifosfamide-containing chemotherapy in osteosarcoma

Liposomal muramyl tripeptide phosphatidyl ethanolamine (L-MTP-PE) is a synthetic biological investigational agent used for treating osteosarcoma. It has been used in both canine and human osteosarcoma to reduce pulmonary metastases, the most common pattern of treatment failure for sarcomas. L-MTP-PE has been well tolerated using the concept of biological cancer therapy during chemotherapy. The use of L-MTP-PE with ifosfamide is the best studied combination with single agent chemotherapy. This may represent a new treatment choice for osteosarcoma patients receiving ifosfamide. Such patients include those with a poor initial histological response to primary therapy and/or metastatic disease including pulmonary metastases. Reduction of side effects of L-MTP-PE, such as fever and/or flu-like symptoms, with ibuprofen has not reduced efficacy. Since improved symptom control is possible using drug combinations that are especially effective for delayed nausea, outpatient high-dose ifosfamide chemotherapy combined with L-MTP-PE may lead to a safe and effective therapy while maintaining the patients’ quality of life.

Protective effects of heat shock protein 70 induced by geranylgeranylacetone on oxidative injury in rat intestinal epithelial cells

OBJECTIVE

Geranylgeranylacetone (GGA), an anti-ulcer agent, has recently been demonstrated to protect a variety of cells and tissues via induction of heat shock protein (HSP)70 against numerous stresses. We investigated whether GGA induces HSP70 and protects against an oxidative stressor, monocrolamine (NH(2)Cl), in a rat intestinal epithelial cell line (IEC-18).

MATERIAL AND METHODS

IEC-18 cells pretreated with GGA (0.1-10 microM) were subjected to injury induced by NH(2)Cl. Cell viability was assessed, and endogenous HSP70 levels were determined by enzyme-linked immunosorbent assay in IEC-18 cells.

RESULTS

Treatment with GGA (0.1-10 microM) was found rapidly to elevate HSP70 levels and to protect against NH(2)Cl-induced injury in IEC-18 cells. Furthermore, quercetin, an inhibitor of HSP70 synthesis, diminished the protective effects of GGA in IEC-18 cells upon NH(2)Cl-caused injury.

CONCLUSIONS

The results of this study suggest that GGA plays an important role in defense mechanisms against oxidative injury in the intestine, primarily via induction of HSP70.

Tumour necrosis factor-alpha production stimulated by heat shock protein 70 and its inhibition in circulating dendritic cells and cells eluted from mucosal tissues in Crohn's disease

Summaryand interleukin (IL)-12 by dendritic cells (DC) from patients with Crohn's disease. TNF-alpha concentration was increased significantly when DC from Crohn's disease were stimulated with HSP70 or CD40L and this was associated with signalling by the extracellular signal regulated kinase (ERK) 1/2 and p38 mitogen activated protein (MAP) kinase pathway. IL-12 production was also increased when DC were stimulated with HSP70. Cells eluted from inflamed intestinal mucosa from Crohn's disease, stimulated with HSP70, CD40L or lipopolysaccharide produced significantly greater TNF-alpha and IL-12 concentrations than cells from uninflamed mucosa. Significant inhibition of TNF-alpha production was demonstrated when DC from peripheral blood mononuclear cells or cells eluted from intestinal mucosa of Crohn's disease were treated with either the HSP70 inhibitory peptide (aa 457-496) or peptides derived from CD40 and CD40L. These inhibitory peptides target the CD40-CD40L and the emerging CD40-HSP70 co-stimulatory pathway. Our findings offer a novel strategy to prevent excessive production of TNF-alpha in Crohn's disease.