Heat Shock Protein 70 Release Research Articles

SARS-CoV-2 Induces Epithelial-Enteric Neuronal Crosstalk Stimulating VIP Release.

Diarrhea is present in up to 30-50% of patients with COVID-19. The mechanism of SARS-CoV-2-induced diarrhea remains unclear. We hypothesized that enterocyte-enteric neuron interactions were important in SARS-CoV-2-induced diarrhea. SARS-CoV-2 induces endoplasmic reticulum (ER) stress in enterocytes causing the release of damage associated molecular patterns (DAMPs). The DAMPs then stimulate the release of enteric neurotransmitters that disrupt gut electrolyte homeostasis. Primary mouse enteric neurons (EN) were exposed to a conditioned medium from ACE2-expressing Caco-2 colonic epithelial cells infected with SARS-CoV-2 or treated with tunicamycin (ER stress inducer). Vasoactive intestinal peptides (VIP) expression and secretion by EN were assessed by RT-PCR and ELISA, respectively. Membrane expression of NHE3 was determined by surface biotinylation. SARS-CoV-2 infection led to increased expression of BiP/GRP78, a marker and key regulator for ER stress in Caco-2 cells. Infected cells secreted the DAMP protein, heat shock protein 70 (HSP70), into the culture media, as revealed by proteomic and Western analyses. The expression of VIP mRNA in EN was up-regulated after treatment with a conditioned medium of SARS-CoV-2-infected Caco-2 cells. CD91, a receptor for HSP70, is abundantly expressed in the cultured mouse EN. Tunicamycin, an inducer of ER stress, also induced the release of HSP70 and Xbp1s, mimicking SARS-CoV-2 infection. Co-treatment of Caco-2 with tunicamycin (apical) and VIP (basolateral) induced a synergistic decrease in membrane expression of Na+/H+ exchanger (NHE3), an important transporter that mediates intestinal Na+/fluid absorption. Our findings demonstrate that SARS-CoV-2 enterocyte infection leads to ER stress and the release of DAMPs that up-regulates the expression and release of VIP by EN. VIP in turn inhibits fluid absorption through the downregulation of brush-border membrane expression of NHE3 in enterocytes. These data highlight the role of epithelial-enteric neuronal crosstalk in COVID-19-related diarrhea.

Different levels of mucus inflammatory mediators in nasal polyposis with and without aeroallergen sensitivity.

ObjectivesBiomarker levels in nasal secretions can reflect the inflammatory status of nasal mucosa and evolution of sinus disease. The aim of this study was to evaluate the relationship between local inflammatory mediator production and clinical characteristics of patients with nasal polyposis (NP).MethodsThirty‐one nonaeroallergen sensitized patients with NP (NANP), 29 aeroallergen sensitized patients with NP (ANP), and 30 subjects without inflammation of nasal mucosa as controls (C) entered this prospective, cross‐sectional study. Clinical parameters (symptoms, endoscopic, and radiological findings) were assessed. The concentrations of heat shock protein 70 (HSP70), eosinophil cationic protein (ECP), tryptase, substance P and Clara cell protein 16 (CC16) were measured in the nasal secretion samples of all participants by ELISA method.ResultsOur results showed higher concentrations of HSP70, ECP, and tryptase in ANP than in NANP and C (p < .001 for all markers). On the other hand, levels of CC16 were significantly higher in C than in NANP and ANP groups (p < .001; p < .001, respectively). We found positive correlations between HSP70, ECP, tryptase, and substance P levels and nasal symptom score in patients with NP. Also, HSP70, ECP, tryptase, and substance P showed different levels of positive correlation among themselves, with HSP70 showing highest positive correlation with ECP. Finally, relatively strong negative correlations were found between the levels of CC16 and nasal symptoms, as well as between the CC16 levels and levels of other four mediators in nasal fluid.ConclusionHSP70, ECP, tryptase, and substance P might play a role in the pathogenesis of NP. The results suggest that chronic inflammation in NP involves a self‐sustaining local release of HSP70, ECP, and tryptase, independent of aeroallergen stimulation of the mucosal layer, although the production of these mediators is higher in aeroallergen sensitized NP patients.

Overcoming Immunotherapy Resistance by Targeting the Tumor-Intrinsic NLRP3-HSP70 Signaling Axis.

Simple SummaryThe tumor-intrinsic NLRP3 inflammasome is a newly recognized player in the regulation of tumor-directed immune responses and promises to provide fresh insight into how tumors respond to immunotherapy. This brief review discusses recent data describing how activation of the tumor-intrinsic NLRP3 inflammasome contributes to immune evasion and what this pathway may provide to the field of immuno-oncology both in terms of pharmacologic targets capable of boosting responses to checkpoint inhibitor therapies and predictive biomarkers indicating which tumors may be most susceptible to these new therapeutic strategies.The tumor-intrinsic NOD-like receptor family, pyrin-domain-containing-3 (NLRP3) inflammasome, plays an important role in regulating immunosuppressive myeloid cell populations in the tumor microenvironment (TME). While prior studies have described the activation of this inflammasome in driving pro-tumorigenic mechanisms, emerging data is now revealing the tumor NLRP3 inflammasome and the downstream release of heat shock protein-70 (HSP70) to regulate anti-tumor immunity and contribute to the development of adaptive resistance to anti-PD-1 immunotherapy. Genetic alterations that influence the activity of the NLRP3 signaling axis are likely to impact T cell-mediated tumor cell killing and may indicate which tumors rely on this pathway for immune escape. These studies suggest that the NLRP3 inflammasome and its secreted product, HSP70, represent promising pharmacologic targets for manipulating innate immune cell populations in the TME while enhancing responses to anti-PD-1 immunotherapy. Additional studies are needed to better understand tumor-specific regulatory mechanisms of NLRP3 to enable the development of tumor-selective pharmacologic strategies capable of augmenting responses to checkpoint inhibitor immunotherapy while minimizing unwanted off-target effects. The execution of upcoming clinical trials investigating this strategy to overcome anti-PD-1 resistance promises to provide novel insight into the role of this pathway in immuno-oncology.

Effect of moxibustion on expressions of HSP70 mRNA and protein in gastric cancer-bearing rats

Objective: To observe the effect of moxibustion on the mRNA and protein expressions of heat-shock protein 70 (HSP70) in gastric cancer-bearing rats. Methods: A total of 40 healthy Sprague-Dawley (SD) rats were adaptively fed for one week. The gastric cancer model was prepared by Walker-256 cancer tissue transplantation. After 7 d, 10 rats were randomly selected to verify the successful modeling, and the remaining 30 rats were divided into a model group, a moxibustion group and an infrared group by the random number table method, with 10 rats in each group. After enrollment, the moxibustion group received suspended moxibustion at Zhongwan (CV 12), Guanyuan (CV 4) and bilateral Zusanli (ST 36), (the first group of acupoints) on the 1st day, and suspended moxibustion at bilateral Pishu (BL 20) and Weishu (BL 21), (the second group of acupoints) on the 2nd day, 20 min each time, once a day. Moxibustion was alternately performed every other day at the two groups of acupoints for 21 d. From the day of enrollment, rats in the infrared group were irradiated with the infrared radiation at the stomach area on the 1st day, and at the T12-T13 interspinous region on the 2nd day, 20 min each time, once a day, and the two locations were alternately irradiated every other day for 21 d. During the treatment, rats in the model group were intervened by grasping and fixation without treatment. At the end of the treatment, blood was collected from the inner eye orbit, and the HSP70 expression in peripheral blood was determined by enzyme linked immunosorbent assay (ELISA). Rats were sacrificed, the tumor volume and growth inhibition rate were measured. The position and changes of HSP70 in gastric cancer were observed by streptavidin-perosidase (SP); HSP70 protein expression was determined by ELISA; HSP70 mRNA expression in cancer tissues was determined by reverse transcription-polymerase chain reaction (RT-PCR) assay. Results: In comparison of the model group, the volume growth of the gastric cancer in the moxibustion group was significantly restricted (P<0.01); the volume growth inhibition rate in the moxibustion group was 37.93%; the HSP70 expression in peripheral blood and the cancer tissues was significantly increased (both P<0.01); the expression of HSP70 mRNA and HSP70 content in gastric tumor were both obviously increased in the moxibustion group (P<0.01); and a large amount of HSP70 was released to the outside of cancer cells in the moxibustion group. In comparison of the model group, the volume growth of the gastric cancer in the infrared group was slightly restricted (P<0.05) with a volume growth inhibition rate of 15.89%; the HSP70 expression in the infrared group was increased significantly in peripheral blood (P<0.01) and in the gastric cancer tissues (P<0.05); more HSP70 was released outside of the cancer cells in the infrared group. In comparison of the infrared group, the volume growth of gastric cancer was more restricted in the moxibustion group (P<0.05), and the HSP70 expression in the gastric cancer tissues was also higher (P<0.05); more HSP70 was released outside of the cancer cells in the moxibustion group. Conclusion: Moxibustion and infrared treatment inhibit the gastric cancer growth in the gastric cancer-bearing rats, up-regulate the HSP70 expression in gastric cancer tissues, and promote the production and extracellular release of HSP70, and the effect of moxibustion is more obvious. Conclusion: Moxibustion and infrared treatment inhibit the gastric cancer growth in the gastric cancer-bearing rats, up-regulate the HSP70 expression in gastric cancer tissues, and promote the production and extracellular release of HSP70, and the effect of moxibustion is more obvious.

Effect of a post-hatch lipopolysaccharide challenge in Turkey poults and ducklings after a primary embryonic heat stress

The effect of embryonic thermal manipulation on the post-hatch immune response to a lipopolysaccharide (LPS) challenge was studied in Pekin ducklings and turkey poults. Commercial duck and turkey eggs were distributed among four treatments: SS-Control (37.5 °C from embryonic day [ED] 1 to 25); SS-LPS (37.5 °C from ED1 to 25 + LPS at D0 [hatch]); HH-LPS (38 °C from ED1 to 25 + LPS at D0; SH-LPS (37.5 °C from ED1 to 10 and 38 °C from ED 11 to 25 + LPS at D0). At ED16 and ED24, the egg shell temperature of the duck and turkey eggs in the HH and SH treatments were higher (P ≤ 0.01) than the SS treatment. Ducklings and poults in the HH treatment had the lowest yolk free body weight at hatch (P ≤ 0.05). At 24, 48, and 72 h post-LPS injection, ducklings and poults in the HH-LPS treatment had significantly reduced BW compared with the SS-Con treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS and HH-LPS treatments had increased plasma heat shock protein 70 (HSP70) and lower splenic HSP70 mRNA amounts than the SS-LPS treatments at 24, and 48 h post-challenge (P ≤ 0.05). At 48 and 72 h, macrophage nitric oxide (NO) production in ducklings and poults in the SH-LPS and HH-LPS treatments was lower than in the SS-LPS treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymocyte proliferation compared to the SS-LPS treatment at 24, 48 and 72 h (P ≤ 0.05). At 24 h, ducklings in the SH-LPS treatment had increased splenic IL-10 and reduced IFNγ and IL-6 mRNA abundance. However, both ducklings and poults in the HH-LPS treatment had increased IFNγ, and IL-10 mRNA abundance compared to the SS-LPS treatment (P ≤ 0.05). At 48 h, SH-LPS ducklings and poults had lower splenic IL-10 mRNA abundance (P ≤ 0.05) while the HH-LPS treatment resulted in comparable splenic IL-10 mRNA compared to the SS-LPS treatment (P ≥ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymic and splenic CD8+/CD4+ ratios at 24 h versus the SS-LPS treatment (P ≤ 0.05). In conclusion, embryonic thermal manipulation from ED11-25 increased extracellular HSP70 release, thymocyte proliferation and IL-10 but decreased splenic HSP70 and IFNγ mRNA amounts at 24 h post-LPS injection. This suggests that mild heat stress during the later stages of incubation could potentially prime the embryonic immune system thereby enhances the immune response as earlier than 24 h to eliminate the inflammatory response without affecting the growth performance by increase the extracellular release of HSP70 in both ducklings and poults. Continuous exposure to the small increase in temperature from ED 1–25 (HH) caused an imbalance between pro (IFNγ)- and anti-inflammatory cytokines(IL-10) which affects hatchling responses to an inflammatory challenge and increased mortality. The amount of extracellular HSP70 could potentially play an important role in modulating the immune response against inflammatory challenges.

Blocking ATP-sensitive potassium channel alleviates morphine tolerance by inhibiting HSP70-TLR4-NLRP3-mediated neuroinflammation

BackgroundLong-term use of morphine induces analgesic tolerance, which limits its clinical efficacy. Evidence indicated morphine-evoked neuroinflammation mediated by toll-like receptor 4 (TLR4) - NOD-like receptor protein 3 (NLRP3) inflammasome was important for morphine tolerance. In our study, we investigated whether other existing alternative pathways caused morphine-induced activation of TLR4 in microglia. We focused on heat shock protein 70 (HSP70), a damage-associated molecular pattern (DAMP), which was released from various cells upon stimulations under the control of KATP channel and bound with TLR4-inducing inflammation. Glibenclamide, a classic KATP channel blocker, can improve neuroinflammation by inhibiting the activation of NLRP3 inflammasome. Our present study investigated the effect and possible mechanism of glibenclamide in improving morphine tolerance via its specific inhibition on the release of HSP70 and activation of NLRP3 inflammasome induced by morphine.MethodsCD-1 mice were used for tail-flick test to evaluate morphine tolerance. The microglial cell line BV-2 and neural cell line SH-SY5Y were used to investigate the pharmacological effects and the mechanism of glibenclamide on morphine-induced neuroinflammation. The activation of microglia was accessed by immunofluorescence staining. Neuroinflammation-related cytokines were measured by western blot and real-time PCR. The level of HSP70 and related signaling pathway were evaluated by western blot and immunofluorescence staining.ResultsMorphine induced the release of HSP70 from neurons. The released HSP70 activated microglia and triggered TLR4-mediated inflammatory response, leading to the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) p65 and the activation of NLRP3 inflammasome. Moreover, anti-HSP70 neutralizing antibody partly attenuated chronic morphine tolerance. The secretion of HSP70 was under the control of MOR/AKT/KATP/ERK signal pathway. Glibenclamide as a classic KATP channel blocker markedly inhibited the release of HSP70 induced by morphine and suppressed HSP70-TLR4-NLRP3 inflammasome-mediated neuroinflammation, which consequently attenuated morphine tolerance.ConclusionsOur study indicated that morphine-induced extracellular HSP70 was an alternative way for the activation of TLR4-NLRP3 in analgesic tolerance. The release of HSP70 was regulated by MOR/AKT/KATP/ERK pathway. Our study suggested a promising target, KATP channel and a new leading compound, glibenclamide, for treating morphine tolerance.

Improving immunological tumor microenvironment using electro-hyperthermia followed by dendritic cell immunotherapy

BackgroundThe treatment of intratumoral dentritic cells (DCs) commonly fails because it cannot evoke immunity in a poor tumor microenvironment (TME). Modulated electro-hyperthermia (mEHT, trade-name: oncothermia) represents a significant technological advancement in the hyperthermia field, allowing the autofocusing of electromagnetic power on a cell membrane to generate massive apoptosis. This approach turns local immunogenic cancer cell death (apoptosis) into a systemic anti-tumor immune response and may be implemented by treatment with intratumoral DCs.MethodsThe CT26 murine colorectal cancer model was used in this investigation. The inhibition of growth of the tumor and the systemic anti-tumor immune response were measured. The tumor was heated to a core temperature of 42 °C for 30 min. The matured synergetic DCs were intratumorally injected 24 h following mEHT was applied.ResultsmEHT induced significant apoptosis and enhanced the release of heat shock protein70 (Hsp70) in CT26 tumors. Treatment with mEHT-DCs significantly inhibited CT26 tumor growth, relative to DCs alone or mEHT alone. The secondary tumor protection effect upon rechallenging was observed in mice that were treated with mEHT-DCs. Immunohistochemical staining of CD45 and F4/80 revealed that mEHT-DC treatment increased the number of leukocytes and macrophages. Most interestingly, mEHT also induced infiltrations of eosinophil, which has recently been reported to be an orchestrator of a specific T cell response. Cytotoxic T cell assay and ELISpot assay revealed a tumor-specific T cell activity.ConclusionsThis study demonstrated that mEHT induces tumor cell apoptosis and enhances the release of Hsp70 from heated tumor cells, unlike conventional hyperthermia. mEHT can create a favorable tumor microenvironment for an immunological chain reaction that improves the success rate of intratumoral DC immunotherapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1690-2) contains supplementary material, which is available to authorized users.

An in vitro model to consider the effect of 2 mM glutamine and KNK437 on endotoxin-stimulated release of heat shock protein 70 and inflammatory mediators

ObjectiveGlutamine has been shown to promote the release of heat shock protein 70 (HSP70) both within experimental in vitro models of sepsis and in adults with septic shock. This study aimed to investigate the effects of 2 mM glutamine and an inhibitor of HSP70 (KNK437) on the release of HSP70 and inflammatory mediators in healthy adult volunteers. MethodsAn in vitro whole blood endotoxin stimulation assay was used. ResultsThe addition of 2 mM glutamine significantly increased HSP70 levels over time (P < 0.05). HSP70 release had a positive correlation at 4 h with IL-1 β (r = 0.51, P = 0.03) and an inverse correlation with TNF-α (r = −0.56, P = 0.02) and IL-8 levels (r = −0.52, P = 0.03), and there were no significant correlations between HSP70 and IL6 or IL-10 or glutamine. Glutamine supplementation significantly (P < 0.05) attenuated the release of IL-10 at 4 h and IL-8 at 24 h, compared with conditions without glutamine. In endotoxin-stimulated blood there were no significant differences in the release of IL-6, TNF-α, and IL-1 β with glutamine supplementation at 4 and 24 h. However, glutamine supplementation (2 mM) appeared to attenuate the release of inflammatory mediators (IL-1 β, IL-6, TNF-α), although this effect was not statistically significant. The addition of KNK437, a HSP70 inhibitor, significantly diminished HSP70 release, which resulted in lower levels of inflammatory mediators (P < 0.05). ConclusionGlutamine supplementation promotes HSP70 release in an experimental model of sepsis. After the addition of KNK437, the effects of glutamine on HSP70 and inflammatory mediator release appear to be lost, suggesting that HSP70 in part orchestrates the inflammatory mediator response to sepsis. The clinical implications require further investigation.

Albumin stimulates renal tubular inflammation through an HSP70-TLR4 axis in mice with early diabetic nephropathy.

ABSTRACTIncreased urinary albumin excretion is not simply an aftermath of glomerular injury, but is also involved in the progression of diabetic nephropathy (DN). Whereas Toll-like receptors (TLRs) are incriminated in the renal inflammation of DN, whether and how albumin is involved in the TLR-related renal inflammatory response remains to be clarified. Here, we showed that both TLR2 and TLR4, one of their putative endogenous ligands [heat shock protein 70 (HSP70)] and nuclear factor-κB promoter activity were markedly elevated in the kidneys of diabetic mice. A deficiency of TLR4 but not of TLR2 alleviated albuminuria, tubulointerstitial fibrosis and inflammation induced by diabetes. The protection against renal injury in diabetic Tlr4−/− mice was associated with reduced tubular injuries and preserved cubilin levels, rather than amelioration of glomerular lesions. In vitro studies revealed that albumin, a stronger inducer than high glucose (HG), induced the release of HSP70 from proximal tubular cells. HSP70 blockade ameliorated albumin-induced inflammatory mediators. HSP70 triggered the production of inflammatory mediators in a TLR4-dependent manner. Moreover, HSP70 inhibition in vivo ameliorated diabetes-induced albuminuria, inflammatory response and tubular injury. Finally, we found that individuals with DN had higher levels of TLR4 and HSP70 in the dilated tubules than non-diabetic controls. Thus, activation of the HSP70-TLR4 axis, stimulated at least in part by albumin, in the tubular cell is a newly identified mechanism associated with induction of tubulointerstitial inflammation and aggravation of pre-existing microalbuminuria in the progression of DN.

The effect of 2 mMol glutamine supplementation on HSP70 and TNF-α release by LPS stimulated blood from healthy children

Glutamine has been shown to promote heat shock protein 70 (HSP70) release both within experimental in vitro models of sepsis (2-10 mM) and in adults post trauma (0.5 g/kg), although the efficacy varies and is dependent on the model used. The effect of glutamine supplementation on HSP70 release in children is less clear. Therefore, the aim of this study was to investigate the effect of 2 mM glutamine added to incubation media on HSP70 and inflammatory mediator release in an in vitro model of paediatric sepsis using whole blood from healthy paediatric volunteers. An in vitro whole blood endotoxin stimulation model using 1 μg/ml lipopolysaccharide (LPS) over a 24 h time period was used to investigate the effects of 2 mM glutamine on HSP70 and inflammatory mediator release in healthy children. The addition of 2 mM glutamine to the incubation media significantly increased HSP70 release over time (p < 0.05). This was associated with an early pro-inflammatory effect on TNF-α release at 4 h (p < 0.005) which was not seen at 24 h. There was a non significant trend towards higher levels of IL-6 and IL-10 following the addition of 2 mM glutamine, which appears to differ from the response reported in adult and animal models. Glutamine supplementation of incubation media promotes HSP70 and early TNF- α release in an in vitro model using blood samples from healthy children.

Pim1 kinase protects airway epithelial cells from cigarette smoke-induced damage and airway inflammation.

Exposure to cigarette smoke (CS) is the main risk factor for developing chronic obstructive pulmonary disease and can induce airway epithelial cell damage, innate immune responses, and airway inflammation. We hypothesized that cell survival factors might decrease the sensitivity of airway epithelial cells to CS-induced damage, thereby protecting the airways against inflammation upon CS exposure. Here, we tested whether Pim survival kinases could protect from CS-induced inflammation. We determined expression of Pim kinases in lung tissue, airway inflammation, and levels of keratinocyte-derived cytokine (KC) and several damage-associated molecular patterns in bronchoalveolar lavage in mice exposed to CS or air. Human bronchial epithelial BEAS-2B cells were treated with CS extract (CSE) in the presence or absence of Pim1 inhibitor and assessed for loss of mitochondrial membrane potential, induction of cell death, and release of heat shock protein 70 (HSP70). We observed increased expression of Pim1, but not of Pim2 and Pim3, in lung tissue after exposure to CS. Pim1-deficient mice displayed a strongly enhanced neutrophilic airway inflammation upon CS exposure compared with wild-type controls. Inhibition of Pim1 activity in BEAS-2B cells increased the loss of mitochondrial membrane potential and reduced cell viability upon CSE treatment, whereas release of HSP70 was enhanced. Interestingly, we observed release of S100A8 but not of double-strand DNA or HSP70 in Pim1-deficient mice compared with wild-type controls upon CS exposure. In conclusion, we show that expression of Pim1 protects against CS-induced cell death in vitro and neutrophilic airway inflammation in vivo. Our data suggest that the underlying mechanism involves CS-induced release of S100A8 and KC.

Interferon-γ Induces Senescence in Normal Human Melanocytes

BackgroundInterferon-γ (IFN-γ) plays an important role in the proceedings of vitiligo through recruiting lymphocytes to the lesional skin. However, the potential effects of IFN-γ on skin melanocytes and the subsequent contribution to the vitiligo pathogenesis are still unclear.ObjectiveTo investigate the effects of IFN-γ on viability and cellular functions of melanocytes.MethodsPrimary human melanocytes were treated with IFN-γ. Cell viability, apoptosis, cell cycle melanin content and intracellular reactive oxygen species (ROS) level were measured. mRNA expression was examined by real-time PCR. The release of interleukin 6 (IL-6) and heat shock protein 70 (HSP-70) was monitored by ELISA. β-galactosidase staining was utilized to evaluate melanocyte senescence.ResultsPersistent IFN-γ treatment induced viability loss, apoptosis, cell cycle arrest and senescence in melanocytes. Melanocyte senescence was characterized as the changes in pigmentation and morphology, as well as the increase of β-galactosidase activity. Increase of p21Cip1/Waf1 protein was evident in melanocytes after IFN-γ treatment. IFN-γ induction of senescence was attenuated by siRNAs against p21, Janus kinase 2 (JAK2) or signal transducer and activator of transcription 1 (STAT1), but not by JAK1 siRNA nor by p53 inhibitor pifithrin-α. IFN-γ treatment increased the accumulation of intracellular ROS in melanocytes, while ROS scavenger N-acetyl cysteine (NAC) effectively inhibited IFN-γ induced p21 expression and melanocyte senescence. IL-6 and HSP-70 release was significantly induced by IFN-γ treatment, which was largely inhibited by NAC. The increase of IL-6 and HSP-70 release could also be observed in senescent melanocytes.ConclusionIFN-γ can induce senescence in melanocytes and consequently enhance their immuno-competency, leading to a vitiligo-prone milieu.

Muscle Heat Shock Protein 70 Predicts Insulin Resistance With Aging

Heat shock protein 70 (HSP70) protects cells from accumulating damaged proteins and age-related functional decline. We studied plasma and skeletal muscle (SkM) HSP70 levels in adult vervet monkeys (life span ≈ 25 years) at baseline and after 4 years (≈10 human years). Insulin, glucose, homeostasis model assessment scores, triglycerides, high-density lipoprotein and total plasma cholesterol, body weight, body mass index, and waist circumference were measured repeatedly, with change over time estimated by individual regression slopes. Low baseline SkM HSP70 was a proximal marker for developing insulin resistance and was seen in monkeys whose insulin and homeostasis model assessment increased more rapidly over time. Changes in SkM HSP70 inversely correlated with insulin and homeostasis model assessment trajectories such that a positive change in SkM level was beneficial. The strength of the relationship between changes in SkM HSP70 and insulin remained unchanged after adjustment for all covariates. Younger monkeys drove these relationships, with HSP70 alone being predictive of insulin changes with aging. Plasma and SkM HSP70 were unrelated and HSP70 release from peripheral blood mononuclear cells was positively associated with insulin concentrations in contrast to SkM. Results from aged humans confirmed this positive association of plasma HSP70 and insulin. In conclusion, higher levels of SkM HSP70 protect against insulin resistance development during healthy aging.

Glutamine depletion and heat shock protein 70 (HSP70) in children with meningococcal disease

Heat shock proteins are classified into six main families, of which HSP70 is the best studied. HSP70 is postulated to modulate the immune/inflammatory response in critical illness. Glutamine promotes HSP70 release, however, little is known about the relationship between glutamine and HSP70 in paediatric critical illness. We therefore aimed to describe plasma levels of HSP70, inflammatory mediators and glutamine in critically ill children. A clinical audit identified 143 children with severe meningococcal disease, 78 convalescent children, in addition to 35 healthy paediatric controls. Stored plasma was used to measure plasma concentrations of HSP70, inflammatory mediators and glutamine. HSP70 was significantly increased on admission (n = 143, mean 26.7 ng/ml; ±SD 79.95) compared with convalescence (n = 78, mean 3.16 ng/ml; ±SD 5.67). Glutamine levels were low (n = 132, mean 0.31 mmol/l; ±SD 0.13), which continued in convalescence (n = 65, mean 0.40 mmol/l; ±SD 0.14). Enteral glutamine provided only 28% of the recommendations. Glutamine was inversely correlated with length-of-stay (n = 98, r = -0.520, p < 0.001), ventilation (n = 98, r = -0.513, p < 0.001), lactate (n = 98, r = -0.41, p < 0.001) and CRP (n = 98, r = -0.51, p < 0.001). HSP70 was correlated with length-of-stay (n = 99, r = 0.30, p < 0.001), ventilation (n = 99, r = 0.31, p < 0.001), lactate (n = 99, r = 0.26, p < 0.001) and CRP (n = 99, r = 0.29, p < 0.001) and inflammatory mediators. There was no relationship between glutamine and HSP70 or inflammatory mediators. During acute illness HSP70/inflammatory mediators are significantly increased, and glutamine is significantly depleted. However, glutamine and HSP70 were not correlated. Enteral feeds only provided a small proportion of the ASPEN/ESPEN recommendations for glutamine.

Elevated Heat Shock Protein 70 (HSP70) Serum Levels After Tumor Radiofrequency Ablation Might Represent a Favorable Prognostic Marker.

Abstract 4748 IntroductionRadiofrequency (RF) ablation is a safe and effective method to locally treat malignancies of the liver, kidney and more recently lung. For the treatment of small tumors, long term results are comparable with outcome after surgical resection and better than current chemotherapies. RF-ablation has now been reported to induce heat shock protein (HSP) expression on sublethally damaged hepatocytes. HSPs are potent alarm signals for the immune system causing i.e. activation of T cells and dendritic cells. In addition to triggering immune responses directed against HSPs themselves, HSPs can carry antigens derived from those cells of which HSPs originated and thereby elicit specific immune reactions against these cellular epitopes. Patients and MethodsWe here analyzed serum samples of 22 patients to evaluate the systemic release of HSP70 using a specific HSP70 ELISA. Patients were followed for a median of 30 months until death or three years after the last RF-treatment. As a control group, sera from 20 patients undergoing diagnostic liver biopsy were screened. ResultsThe median increase of HSP70 in serum comparing levels before and one day after the procedures was 1.6-fold in the RF-ablation group, while no soluble HSP-70 could be detected in the control group before and after the biopsy. Nine patients showed a higher than two-fold increase of HSP70 in the serum after ten sessions of RF-ablation compared to levels prior to treatment. No correlation of HSP70 levels with tumor volume, the ablated non-malignant tissue or the total size of the necrosis was observed. In the subgroup of patients with elevated HSP-70 serum levels, 67% (6 out of 9) were alive at the end of follow up with only one suffering from progressive disease. In contrast, 61% (8 out of 13) of the other patients suffered from progressive disease or had deceased at the end of follow-up. ConclusionRF-ablation not only induces cellular HSP expression but also can lead to a systemic release of serum HSP70. Patients with strong increases in HSP-70 serum levels tended to have a better survival than patients without induction of HSP-70 in the serum. Thus, immunomodulation might represent an additional beneficial effect of RF-ablation besides local tumor destruction, since HSPs are strong stimuli for the immune system and can mediate tumor-specific T cell immunity. Disclosures:No relevant conflicts of interest to declare.

Heat shock protein 70 is secreted from endothelial cells by a non-classical pathway involving exosomes

Emerging evidence suggests that a high level of circulating heat shock protein 70 (HSP70) correlates with a lower risk of vascular disease; however, the biological significance of this inverse relationship has not been explored. Herein, we report that oxidative low density lipoprotein (Ox-LDL) and homocysteine (Hcy) induce HSP70 release from endothelial cells. In rat endothelial cells, Ox-LDL and Hcy induced robust release of HSP70, independent of the classical route of endoplasmic reticulum/Golgi protein trafficking or the formation of lipid rafts. In contrast, Ox-LDL and Hcy significantly enhanced the exosomal secretory rate and increased the HSP70 content of exosomes. Exogenous HSP70 had no impact on LPS-, Ox-LDL- and Hcy-induced activation of endothelial cells, whereas HSP70 did activate monocytes alone, resulting in monocyte adhesion to endothelial cells. These results indicate that exosome-dependent secretion of HSP70 from endothelial cells provides a novel paracrine mechanism to regulate vascular endothelial functional integrity.

Hyperthermic stimulation of blood increases the immunological effects of granulocyte and monocyte adsorption in vitro: Relevance to extracorporeal immunomodulation

Extracorporeal granulocyte and monocyte/macrophage adsorption (GMA) using an adacolumn filled with cellulose acetate beads as GMA carriers selectively depletes excess and activated myeloid leucocytes from the circulation and has been used as a non-pharmacologic adjunct therapy in patients with inflammatory bowel disease (IBD). In this study we applied hyperthermic stimulation of blood during exposure to the GMA carriers with the aim of enhancing the release of anti-inflammatory substances from leucocytes. In blood from patients with Crohn’s disease (CD) and healthy controls (HC), incubation with the carriers was associated with a striking increase in the release of interleukin-1 receptor antagonist (IL-1ra, a powerful anti-inflammatory cytokine) independent of hyperthermic stimulation, while in the blood from both CD and HC, the release of heat shock protein70 (Hsp70, a cytoprotective protein) was increased by two fold. The present data indicate that hyperthermic stimulation of blood at 43 °C or exposure to cellulose acetate carriers is a simple strategy to generate substances of therapeutic potential from blood, especially in patients with IBD. These observations are very interesting in the context of extracorporeal immunomodulation in patients with immune pathology.

Heat induced release of Hsp70 from prostate carcinoma cells involves both active secretion and passive release from necrotic cells

Purpose: Heat shock protein 70 (HSP70) is released from tumour cells and stimulates a potent anti-tumour immune response.Methods: This study examined the role of hyperthermia, including heating conditions from the fever range, the hyperthermia range and the thermal ablation range, in HSP70 release from prostate carcinoma cells. It has observed HSP70 release from human prostate carcinoma cell lines (PC-3 and LNCaP) treated with hyperthermia.Results: The effects of hyperthermia were complex and appeared to involve at least two mechanisms for HSP70 release. Hyperthermia at 40°C strongly stimulated HSP70 release by an active secretion pathway. However, as temperatures were increased, this rapid secretion pathway became progressively inhibited and by a temperature of 55°C, active secretion was abolished. However, when cells exposed to these heating conditions were allowed to recover at 37°C for 24 h after heating, HSP70 release was observed at the high ablation temperature range and this appeared to be related to a concomitant damage to the plasma membrane.Conclusions: Thus, at least two mechanisms contribute to HSP70 release during hyperthermia and the relative contribution from each pathway depends on the temperature conditions.

Photodynamic Therapy–Induced Cell Surface Expression and Release of Heat Shock Proteins: Relevance for Tumor Response

Almost instantaneously after the treatment of mouse SCCVII tumor cells with Photofrin-based photodynamic therapy (PDT), a fraction (15-25%) of total cellular heat shock protein 70 (HSP70) became exposed at the cell surface. The level of this surface-expressed HSP70 then remained unchanged for the next 6 hours and persisted at lower levels even at 18 hours after PDT. A similar induction of surface HSP70 expression was found with PDT-treated human umbilical vein endothelial cells. The same analysis for several other HSPs revealed the induced surface expression of HSP60 and GRP94, but not GRP78, on PDT-treated SCCVII cells. A fraction of total HSP70 existing in SCCVII cells at the time of PDT treatment was promptly (within 1 hour) released from cells after high treatment doses, whereas even lower PDT doses induced a substantial HSP70 release at later time intervals. Macrophages coincubated with PDT-treated SCCVII cells displayed elevated levels of both HSP70 and GRP94 on their surface and were stimulated to produce tumor necrosis factor alpha, whose production was inhibited by the presence of antibodies against either HSP70, Toll-like receptors 2 and 4, or specific NF-kappaB inhibitor in the coincubation medium. The induction of cell surface expression and release of HSPs by PDT may represent an important event in the response of tumors to this treatment modality with a critical role in the induced inflammatory and immune responses that contribute to the therapeutic outcome.

Nitric Oxide Mediates IL-1β Stimulation of Heat Shock Protein but Not IL-1β Inhibition of Glutamic Acid Decarboxylase

Interleukin-1β (IL-1β) has been implicated to play an important role in the autoimmune β cell lesion of insulin-dependent diabetes mellitus (IDDM) because of its inhibition of insulin secretion, direct islet cytotoxicity and alteration of islet cell antigen expression. We have previously demonstrated that IL-1β inhibits glutamic acid decarboxylase-65 (GAD-65) and increases heat shock protein-70 (HSP-70) expression in islet cells. IL-1β stimulates the inducible form of nitric oxide (NO) synthase and the resultant increased NO mediates many of IL-1β's effects. In this study we investigated the role of the NO pathway in mediating the effects of IL-1β on GAD-65 and HSP-70 expression and on insulin secretion. Islets isolated from Sprague-Dawley rats were cultured with IL-1β and aminoguanidine (AG), an inhibitor of inducible NO synthase, individually and in combination for 24 h. Accumulated nitrite production, insulin release and islet expression of GAD-65 and HSP-70 were measured. We found that (1) IL-1β at 10U/ml increased nitrite production, inhibited insulin release, increased HSP-70 expression and decreased GAD-65 expression. (2) AG alone at 1 mM/ml had no effect on nitrite production, insulin release, GAD-65 and HSP-70 expression. (3) In combination, AG completely blocked IL-1β increased nitrite production, reversed IL-1β inhibited insulin release by approximately 50%, completely reversed IL-1β increased HSP-70 expression, but did not reverse IL-1β inhibited GAD-65 expression. Our findings indicate that the effect of IL-1β on HSP-70 expression is mediated by NO production, whereas a NO-independent pathway is involved in the effect of IL-1β on GAD-65 expression and insulin secretion.