A novel heat-shock protein coinducer boosts stress protein Hsp70 to activate T cell regulation of inflammation in autoimmune arthritis

Human type 1 conventional dendritic cells contribute to skin transplant rejection

The skin is the most immunogenic tissue in transplantation and the most difficult tissue in which to induce immune modulation. Batf3-dependent type 1 conventional dendritic cells (cDC1s) are important in initiating rejection in murine skin transplantation. In humans, the CD141+ cDC1 subset is the functional counterpart of the murine Batf3-dependent cDC1s. However, their contribution to the rejection of human skin allografts remains unknown. Using samples from human face and upper extremity transplant recipients, we demonstrated that CD141+ cDC1s are increased and more activated in human skin grafts than native skin tissue from the same individual. Moreover, circulating and tissue CD141+ cDC1s were elevated at rejection time points. Local modulation of graft CD141+ cDC1s decreased HLA-DR expression and increased regulatory T cells, which correlated with a decreased presence of skin allogeneic T cells in a humanized transplantation model. Thus, CD141+ cDC1s play an important role in rejecting human skin allografts, and their local modulation is a promising therapeutic approach.

The molecular basis of the immunomodulatory effects of natural products: A comprehensive review

BACKGROUND

Natural products (NPs) have long been recognized for their potential to modulate the immune system, offering a natural and holistic approach to enhancing immune function. In recent years, the immunomodulation effects of various natural products have attained significant attention.

PURPOSE

This article provides an overview of the role of natural products in immunomodulation, exploring their mechanisms of action, common types of NPs with immunomodulation properties, clinical applications, as well as considerations for their safety and efficacy.

METHODS

Extensive research has been conducted to compile important discoveries on the immunomodulatory properties of NPs through thorough searches of multiple databases such as PubMed, Science Direct, and Scopus up until January 2024.

RESULTS

By decreasing the levels of Th2 cytokines and pro-inflammatory cytokines, the results suggested that NPs have the ability to modulate the immune system. Therefore, NPs alleviate inflammation in various disorders such as asthma and cancer. Furthermore, the observed increase in CD4 cells and IFN-ɣ/IL4 levels, along with an increased IFN-c/IL4 ratio, indicates a stimulatory effect of NPs on Th1 activity in various inflammatory conditions. Therefore, NPs regulate the immune system by inhibiting T-cells and decreasing the growth of young B-cell lymphoma cells.

CONCLUSION

Reviewing studies indicated that NPs have the potential to serve as immunomodulatory candidates for treating disorders characterized by immune dysregulation. However, additional experimental and clinical studies are necessary before these agents can be implemented in clinical settings.

Resolution of inflammation in chronic disease via restoration of the heat shock response (HSR)

Effective resolution of inflammation via the heat shock response (HSR) is pivotal in averting the transition to chronic inflammatory states. This transition characterizes a spectrum of debilitating conditions, including insulin resistance, obesity, type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular ailments. This manuscript explores a range of physiological, pharmacological, and nutraceutical interventions aimed at reinstating the HSR in the context of chronic low-grade inflammation, as well as protocols to assess the HSR. Monitoring the progression or suppression of the HSR in patients and laboratory animals offers predictive insights into the organism's capacity to combat chronic inflammation, as well as the impact of exercise and hyperthermic treatments (e.g., sauna or hot tub baths) on the HSR. Interestingly, a reciprocal correlation exists between the expression of HSR components in peripheral blood leukocytes (PBL) and the extent of local tissue proinflammatory activity in individuals afflicted by chronic inflammatory disorders. Therefore, the Heck index, contrasting extracellular 70 kDa family of heat shock proteins (HSP70) (proinflammatory) and intracellular HSP70 (anti-inflammatory) in PBL, serves as a valuable metric for HSR assessment. Our laboratory has also developed straightforward protocols for evaluating HSR by subjecting whole blood samples from both rodents and human volunteers to ex vivo heat challenges. Collectively, this discussion underscores the critical role of HSR disruption in the pathogenesis of chronic inflammatory states and emphasizes the significance of simple, cost-effective tools for clinical HSR assessment. This understanding is instrumental in the development of innovative strategies for preventing and managing chronic inflammatory diseases, which continue to exert a substantial global burden on morbidity and mortality.

Introducing Molecular Chaperones into the Causality and Prospective Management of Autoimmune Hepatitis

Molecular chaperones influence the immunogenicity of peptides and the activation of effector T cells, and their pathogenic roles in autoimmune hepatitis are unclear. Heat shock proteins are pivotal in the processing and presentation of peptides that activate CD8+ T cells. They can also induce regulatory B and T cells and promote immune tolerance. Tapasin and the transporter associated with antigen processing-binding protein influence the editing and loading of high-affinity peptides for presentation by class I molecules of the major histocompatibility complex. Their over-expression could enhance the autoimmune response, and their deficiency could weaken it. The lysosome-associated membrane protein-2a isoform in conjunction with heat shock cognate 70 supports the importation of cytosolic proteins into lysosomes. Chaperone-mediated autophagy can then process the peptides for activation of CD4+ T cells. Over-expression of autophagy in T cells may also eliminate negative regulators of their activity. The human leukocyte antigen B-associated transcript three facilitates the expression of class II peptide receptors, inhibits T cell apoptosis, prevents T cell exhaustion, and sustains the immune response. Immunization with heat shock proteins has induced immune tolerance in experimental models and humans with autoimmune disease by inducing regulatory T cells. Therapeutic manipulation of other molecular chaperones may promote T cell exhaustion and induce tolerogenic dendritic cells. In conclusion, molecular chaperones constitute an under-evaluated family of ancillary proteins that could affect the occurrence, severity, and outcome of autoimmune hepatitis. Clarification of their contributions to the immune mechanisms and clinical activity of autoimmune hepatitis could have therapeutic implications.

Carvacrol-A Natural Phenolic Compound with Antimicrobial Properties

The main purpose of this article is to present the latest research related to selected biological properties of carvacrol, such as antimicrobial, anti-inflammatory, and antioxidant activity. As a monoterpenoid phenol, carvacrol is a component of many essential oils and is usually found in plants together with its isomer, thymol. Carvacrol, either alone or in combination with other compounds, has a strong antimicrobial effect on many different strains of bacteria and fungi that are dangerous to humans or can cause significant losses in the economy. Carvacrol also exerts strong anti-inflammatory properties by preventing the peroxidation of polyunsaturated fatty acids by inducing SOD, GPx, GR, and CAT, as well as reducing the level of pro-inflammatory cytokines in the body. It also affects the body's immune response generated by LPS. Carvacrol is considered a safe compound despite the limited amount of data on its metabolism in humans. This review also discusses the biotransformations of carvacrol, because the knowledge of the possible degradation pathways of this compound may help to minimize the risk of environmental contamination with phenolic compounds.

Juvenile growth, thermotolerance and gut histomorphology of broiler chickens fed Curcuma longa under hot-humid environments

Background

This study was conducted to assess the juvenile development, thermotolerance, and intestinal morphology of broiler chickens fed Curcuma longa in a hot-humid environment.

Methods

In a Completely Randomized Design, 240 broiler chicks were randomly assigned to four nutritional treatments of baseline diets supplemented with 0 (CN), 4 (FG), 8 (EG), and 12 g (TT) of turmeric powder/Kg of feed, with four replicates of fifteen birds each. Data on feed consumption and body weights were evaluated weekly during the juvenile growth phase. The physiological indicators of the birds were assessed on day 56 of their lives. The birds were subjected to thermal challenge and data were collected on their physiological traits. Eight birds were randomly selected, euthanized and dissected in each treatment, and 2 cm segments of duodenum, jejunum, and ileum were sampled for villi width, villi height, crypt depth, and the villi height: crypt depth ratio measurements.

Results

It was revealed that the weight gain of the birds in EG was significantly greater (p < 0.05) than that of CN birds. The birds in TT, FG, and CN had comparable but smaller duodenal villi than those in EG. The ileal crypt depth in EG chickens was smaller than in CN but comparable to the other treatment groups. In the duodenum, the villi to crypt depth ratio was in the order EG > TT > FG > CN.

Conclusions

To conclude, dietary supplementation of Curcuma longa powder, notably the 8 g/kg diet improved the antioxidant status, thermotolerance, and nutrient absorption by improving intestinal morphology in broiler chickens in a hot-humid environment.

Atrazine exposure induces necroptosis through the P450/ROS pathway and causes inflammation in the gill of common carp (Cyprinus carpioL.)

Atrazine (ATR) is used worldwide and has been confirmed be hazardous materials that harmful to the health of organisms. Since ATR was more persistent in the water, the specific damage caused by ATR to aquatic organisms should be concern. The role of P450/ROS has been proposed in many pathomechanisms. To explore whether P450/ROS mediated necroptosis and promote inflammatory response caused by ATR exposure, 120 common carp (Cyprinus carpio L.) were randomly divided into four groups which were exposed to 0 μg/L, 4 μg/L, 40 μg/L and 400 μg/L ATR respectively. The residual levels of ATR and its metabolites increased, signs of necrosis and inflammation were found in the gills of the ATR-treatment groups. The levels of ROS and cytochrome P450 content were increased, and P450 enzymes were activated. The expression levels of the core components of necroptosis (RIPK1, RIPK3 and MLKL) increased. Moreover, gene expression of inflammatory factors (TNF-α, NF-κB, iNOS, COX-2, IL-1β and PTGE) increased significantly in the ATR-spiked group. Our results suggested that ATR exposure triggered necroptosis through the P450/ROS pathway and causes inflammation of common carp gill. This study provides valuable clue about the mechanism by which ATR causes injury to common carp gill.

Heat Shock Protein 90 (Hsp90) and Hsp70 as Potential Therapeutic Targets in Autoimmune Skin Diseases

Over a hundred different autoimmune diseases have been described to date, which can affect every organ in the body, including the largest one, the skin. In fact, up to one-fifth of the world's population suffers from chronic, noninfectious inflammatory skin diseases, the development of which is significantly influenced by an autoimmune response. One of the hallmarks of autoimmune diseases is the loss of immune tolerance, which leads to the formation of autoreactive lymphocytes or autoantibodies and, consequently, to chronic inflammation and tissue damage. The treatment of autoimmune skin diseases mainly focuses on immunosuppression (using, e.g., corticosteroids) but almost never leads to the development of permanent mechanisms of immune tolerance. In addition, current therapies and their long-term administration may cause serious adverse effects. Hence, safer and more effective therapies that bring sustained balance between pro- and anti-inflammatory responses are still desired. Both intra- and extracellular heat shock proteins (Hsps), specifically well-characterized inducible Hsp90 and Hsp70 chaperones, have been highlighted as therapeutic targets for autoimmune diseases. This review presents preclinical data on the involvement of Hsp90 and Hsp70 in modulating the immune response, specifically in the context of the treatment of selected autoimmune skin diseases with emphasis on autoimmune bullous skin diseases and psoriasis.

DCAF12 and HSPA1A May Serve as Potential Diagnostic Biomarkers for Myasthenia Gravis

Background

Myasthenia gravis (MG) is an autoimmune disease that severely affects the life quality of patients. This study explores the differences in immune cell types between MG and healthy control and the role of immune-related genes in the diagnosis of MG.

Methods

The GSE85452 dataset was downloaded from the Gene Expression Omnibus (GEO) database and analyzed using the limma package to determine differentially expressed genes (DEGs) between patients with MG and the control group. Differentially expressed immune cells were analyzed using single-sample gene set enrichment analysis (GSEA), while immune cell-associated modules were identified by weighted gene coexpression network analysis (WGCNA). Then, the expression of the identified hub genes was confirmed by RT-PCR in peripheral blood mononuclear cells (PBMCs) of MG patients. The R package pROC was used to plot the receiver operating characteristics (ROC) curves.

Results

The modules related to CD56bright natural killer cells were identified by GSEA and WGCNA. The proportion of CD56bright natural killer cells in the peripheral blood of MG patients is low. The results of RT-PCR showed that the levels of DDB1- and CUL4-associated factor 12 (DCAF12) and heat shock protein family A member 1A (HSPA1A) were significantly decreased in peripheral blood mononuclear cells of MG patients compared with healthy controls. The ROC curve results of DCAF12 and HSPA1A mRNA in MG diagnosis were 0.780 and 0.830, respectively.

Conclusions

CD56bright NK cell is lower in MG patients and may affect MG occurrence. DCAF12 and HSPA1A are lowly expressed in PBMCs of MG patients and may serve as the diagnostic biomarkers of MG.

Transcriptomics of chicken cecal tonsils and intestine after infection with low pathogenic avian influenza virus H9N2

Influenza viruses cause severe respiratory infections in humans and birds, triggering global health concerns and economic burden. Influenza infection is a dynamic process involving complex biological host responses. The objective of this study was to illustrate global biological processes in ileum and cecal tonsils at early time points after chickens were infected with low pathogenic avian influenza virus (LPAIV) H9N2 through transcriptome analysis. Total RNA isolated from ileum and cecal tonsils of non-infected and infected layers at 12-, 24- and 72-h post-infection (hpi) was used for mRNA sequencing analyses to characterize differentially expressed genes and overrepresented pathways. Statistical analysis highlighted transcriptomic signatures significantly occurring 24 and 72 hpi, but not earlier at 12 hpi. Interferon (IFN)-inducible and IFN-stimulated gene (ISG) expression was increased, followed by continued expression of various heat-shock proteins (HSP), including HSP60, HSP70, HSP90 and HSP110. Some upregulated genes involved in innate antiviral responses included DDX60, MX1, RSAD2 and CMPK2. The ISG15 antiviral mechanism pathway was highly enriched in ileum and cecal tonsils at 24 hpi. Overall, most affected pathways were related to interferon production and the heat-shock response. Research on these candidate genes and pathways is warranted to decipher underlying mechanisms of immunity against LPAIV in chickens.

The Role of Polyphenols in Regulation of Heat Shock Proteins and Gut Microbiota in Weaning Stress

Gut microbiota is the natural residents of the intestinal ecosystem which display multiple functions that provide beneficial effects on host physiology. Disturbances in gut microbiota in weaning stress are regulated by the immune system and oxidative stress-related protein pathways. Weaning stress also alters gut microbiota response, limits digestibility, and influences animal productive performance through the production of inflammatory molecules. Heat shock proteins are the molecular chaperones that perform array functions from physiological to pathological point of view and remodeling cellular stress response. As it is involved in the defense mechanism, polyphenols ensure cellular tolerance against enormous stimuli. Polyphenols are nature-blessed compounds that show their existence in plenty of amounts. Due to their wider availability and popularity, they can exert strong immunomodulatory, antioxidative, and anti-inflammatory activities. Their promising health-promoting effects have been demonstrated in different cellular and animal studies. Dietary interventions with polyphenols may alter the gut microbiome response and attenuate the weaning stress related to inflammation. Further, polyphenols elicit health-favored effects through ameliorating inflammatory processes to improve digestibility and thereby exert a protective effect on animal production. Here, in this article, we will expand the role of dietary polyphenol intervention strategies in weaning stress which perturbs gut microbiota function and also paid emphasis to heat shock proteins in gut health. This review article gives new direction to the feed industry to formulate diet containing polyphenols which would have a significant impact on animal health.

Biomarkers of non-infectious inflammatory CNS diseases in dogs: Where are we now? Part 2 - Steroid responsive meningitis-arteritis

Steroid responsive meningitis-arteritis (SRMA) in dogs causes severe inflammation of meningeal arteries leading to generalized meningitis with possible neurological signs, as well as a systemic inflammatory response. The etiology and exact pathogenesis are unknown, but an immune-mediated origin has been suggested and is supported by a positive response to immunosuppressive treatment with corticosteroids. A collection of clinical and paraclinical characteristics may be highly indicative of SRMA, but a single and conclusive diagnostic test or biomarker is currently not available. The aim of this review is to provide an overview of the current understanding and knowledge on SRMA, with special emphasis on potential biomarkers and their applicability in the diagnostic work-up. Though no specific markers for SRMA currently exist, clinically useful markers include IgA and several acute phase proteins e.g. C-reactive protein. A frequent problem of both acknowledged and proposed biomarkers, is, however, their inability to effectively differentiate SRMA from other systemic inflammatory conditions. Other proposed diagnostic markers include genetic markers, acute phase proteins such as serum amyloid A, cytokines such as interleukin-17 and CC-motif ligand 19, endocannabinoid receptors and heat shock protein 70; these suggestions however either lack specificity or need further investigation.

The Role of Heat Shock Protein 70 kDa in Asthma

Asthma is a complex chronic disorder of the airways, affecting immune and structural cells and inducing both protein and tissue remodeling. Heat shock proteins 70 kDa (HSP70s) are highly conserved members of the stress-induced family, possessing precisely described chaperone activity. There is growing evidence of a tight relationship between inflammatory diseases of different origins and the elevation of local HSP70 expression and secretion. Although extracellular HSP70 does not serve as a common marker of asthma, elevated HSP70 levels have been detected in the peripheral blood serum and sputum of patients with asthma, as well as in the bronchoalveolar lavage fluid of mice with induced allergic airway inflammation. Possessing diverse immunomodulating properties, extracellular HSP70 can manifest different activities in airway inflammatory processes and asthma, acting either as a pro-inflammatory trigger, or an anti-inflammatory agent. This review will discuss the effects and possible mechanisms concerning HSP70 implication in airway inflammation regulation in asthma. We examine ATPase and chaperone activities of HSP70 as potential modulators of immune responses in asthma. Given the crucial role of a chronic inflammatory response in asthma, understanding the effects of HSP70 on immune and structural cells may reveal new perspectives for the therapeutic control of inflammation.

Autologous extracellular Hsp70 exerts a dual role in rheumatoid arthritis

Extracellular heat shock proteins (Hsp) influence the adaptive immune response and may ameliorate pathogenesis of autoimmune diseases. While some preclinical observations suggest that highly conserved bacterial and/or murine Hsp70 peptides have potential utility in treatment of rheumatoid arthritis (RA) via induction of T regulatory cells (Treg), the role of extracellular inducible human Hsp70 in adaptive immune processes requires further investigation. The present study evaluated Hsp70 influence on inflammatory cytokine-mediated modulation of T cell immunophenotype in ways that influence RA onset and severity. Initial experiments in the present investigation revealed that serum levels of Hsp70 are approximately 2-fold higher in RA patients versus healthy control subjects. To explore the effect of extracellular Hsp70 on key processes underlying the adaptive immune system, the effects of a highly pure, substrate-, and endotoxin-free human Hsp70 on polarization of the T helper cell subpopulations, including CD4+IL-17+ (Th17), CD4+FoxP3+ (Treg), CD4+IFN-γ+ (Th1), and CD4+IL-4+ (Th2), were studied in naïve human peripheral blood mononuclear cell (PBMC) cultures stimulated with anti-CD3/28 mAb. Major findings included an observation that while Hsp70 treatment increased Th17 frequencies and Th17/Treg ratio, the frequency of Th1 cells and the Th1/Th2 ratio were significantly decreased in the Hsp70-treated PBMC cultures. Moreover, data shown here provides preliminary suggestion that major contributing Hsp70-mediated immunomodulation includes interleukin 6 (IL-6) influence on Th17/Treg and Th1/Th2, since expression of this inflammatory cytokine is enhanced by in vitro Hsp70 treatment. These results are nevertheless preliminary and require further investigation to validate the above model.

Selenoprotein Gpx3 knockdown induces myocardial damage through Ca2+ leaks in chickens

Glutathione peroxidase 3 (Gpx3) is a pivotal selenoprotein that acts as an antioxidant. However, the role of Gpx3 in maintaining the normal metabolism of cardiomyocytes remains to be elucidated in more detail. Herein, we employed a model of Gpx3 interference in chicken embryos in vivo and Gpx3 knockdown chicken cardiomyocytes in vitro. Real-time PCR, western blotting and fluorescent staining were performed to detect reactive oxygen species (ROS), the calcium (Ca²⁺) concentration, endoplasmic reticulum (ER) stress, myocardial contraction, inflammation and heat shock proteins (HSPs). Our results revealed that Gpx3 suppression increased the level of ROS, which induced Ca²⁺ leakage in the cytoplasm by blocking the expression of Ca²⁺ channels. The imbalance of Ca²⁺ homeostasis triggered ER stress and blocked myocardial contraction. Furthermore, we found that Ca²⁺ imbalance in the cytoplasm induced severe inflammation, and HSPs might play a protective role throughout these processes. In conclusion, Gpx3 suppression induces myocardial damage through the activation of Ca²⁺-dependent ER stress.

Heat Shock Protein 70 as a Double Agent Acting Inside and Outside the Cell: Insights into Autoimmunity

Heat shock proteins (Hsp) are a diverse group of constitutive and/or stress-induced molecules that are categorized into several classes on the basis of their molecular weight. Mammalian Hsp have been mostly regarded as intracellular chaperones that mediate a range of essential cellular functions, including proper folding of newly synthesized polypeptides, refolding of denatured proteins, protein transport, and stabilization of native proteins' structures. The well-characterized and highly evolutionarily conserved, stress-inducible 70-kDa heat shock protein (Hsp70), is a key molecular chaperone that is overexpressed in the cell in response to stress of various origin. Hsp70 exhibits an immunosuppressive activity via, e.g., downregulation of the nuclear factor-kappa B (NF-κB) activation, and pharmacological induction of Hsp70 can ameliorate the autoimmune arthritis development in animal models. Moreover, Hsp70 might be passively or actively released from the necrotic or stressed cells, respectively. Highly immunogenic extracellular Hsp70 has been reported to impact both the innate and adaptive immune responses, and to be implicated in the autoimmune reaction. In addition, preclinical studies revealed that immunization with highly conserved Hsp70 peptides could be regarded as a potential treatment target for autoimmune arthritis, such as the rheumatoid arthritis, via induction of antigen-specific regulatory T helper cells (also called Treg). Here, a dual role of the intra- and extracellular Hsp70 is presented in the context of the autoimmune reaction.

Mechanistic implications of altered protein expression in rheumatic heart disease

Rheumatic heart disease (RHD) is a major cause of cardiovascular morbidity and mortality in low- and middle-income countries, where living conditions promote spread of group A β-haemolytic streptococcus. Autoimmune reactions due to molecular mimicry of bacterial epitopes by host proteins cause acute rheumatic fever (ARF) and subsequent disease progression to RHD. Despite knowledge of the factors that predispose to ARF and RHD, determinants of the progression to valvular damage and the molecular events involved remain incompletely characterised. This review focuses on altered protein expression in heart valves, myocardial tissue and plasma of patients with RHD and pathogenic consequences on RHD. Proteins mainly involved in structural organization of the valve matrix, blood homeostasis and immune response were altered due to RHD pathogenesis. Study of secreted forms of these proteins may aid the development of non-invasive biomarkers for early diagnosis and monitoring outcomes in RHD. Valve replacement surgery, the single evidence-based strategy to improve outcomes in severe RHD, is costly, largely unavailable in low- and middle-income countries (LMIC) and requires specialised facilities. When diagnosed early, penicillin prophylaxis may be used to delay progression to severe valvular damage. Echocardiography and cardiovascular magnetic resonance and the standard imaging tools recommended to confirm early diagnosis remain largely unavailable and inaccessible in most LMIC and both require expensive equipment and highly skilled persons for manipulation as well as interpretation of results. Changes in protein expression in heart valves and myocardium are associated with progressive valvular deformation in RHD. Understanding these protein changes should shed more light on the mechanisms of pathogenicity, while secreted forms of these proteins may provide leads towards a biomarker for non-invasive early detection of RHD.

Carvacrol Induces Candida albicans Apoptosis Associated With Ca2+/Calcineurin Pathway

As the prevalence of systemic fungal infections caused by Candida albicans gradually increases, it is necessary to explore potential and effective antifungals. Carvacrol is reported to be lethally toxic to C. albicans, involving several potential mechanisms. However, the form and specific mechanism of cell death caused by this compound has not been delineated. In this study, we found that carvacrol could significantly decrease C. albicans survival rates, consistent with previous researches. Further examination proved that carvacrol treatment caused cell membrane permeability and depolarization. To elucidate the association between cell death and apoptosis, DNA fragmentation and metacaspase activation were determined; as expected, these two apoptosis-related markers were clearly observed. Moreover, total and mitochondrial reactive oxygen species (ROS) levels were elevated, and both mitochondrial transmembrane potential and morphology were disrupted. Additionally, cytosolic and mitochondrial calcium levels were also increased by carvacrol. Calcineurin inhibition experiments revealed cyclosporine A (CsA) addition notably rescued cell growth and inhibited metacaspase activation, indicating that carvacrol triggered C. albicans apoptosis through inducing calcineurin activation. Carvacrol was demonstrated to both have low toxicity and be effective in alleviating systemic infections with C. albicans, which might be via its antifungal and immunomodulation activities. This study suggests that carvacrol has excellent potential as a natural protective compound against C. albicans infections.

Leucinostatin acts as a co-inducer for heat shock protein 70 in cultured canine retinal pigment epithelial cells

Dysregulation of retinal pigment epithelium (RPE) cells is the main cause of a variety of ocular diseases. Potentially heat shock proteins, by preventing molecular and cellular damage and modulating inflammatory disease, may exert a protective role in eye disease. In particular, the inducible form of heat shock protein 70 (Hsp70) is widely upregulated in inflamed tissues, and in vivo upregulation of Hsp70 expression by HSP co-inducing compounds has been shown to be a potential therapeutic strategy for inflammatory diseases. In order to gain further understanding of the potential protective effects of Hsp70 in RPE cells, we developed a method for isolation and culture of canine RPE cells. Identity of RPE cells was confirmed by detection of its specific marker, RPE65, in qPCR, flow cytometry, and immunocytochemistry analysis. The ability of RPE cells to express Hsp70 upon experimental induction of cell stress, by arsenite, was analyzed by flow cytometry. Finally, in search of a potential Hsp70 co-inducer, we investigated whether the compound leucinostatin could enhance Hsp70 expression in stressed RPE cells. Canine RPE cells were isolated and cultured successfully. Purity of cells that strongly expressed RPE65 was over 90%. Arsenite-induced stress led to a time- and dose-dependent increase in Hsp70 expression in canine RPE cells in vitro. In addition, leucinostatin, which enhanced heat shock factor-1-induced transcription from the heat shock promoter in DNAJB1-luc-O23 reporter cell line, also enhanced Hsp70 expression in arsenite-stressed RPE cells, in a dose-dependent fashion. These findings demonstrate that leucinostatin can boost Hsp70 expression in canine RPE cells, most likely by activating heat shock factor-1, suggesting that leucinostatin might be applied as a new co-inducer for Hsp70 expression.

Downy Lavender Oil: A Promising Source of Antimicrobial, Antiobesity, and Anti-Alzheimer's Disease Agents

Lavandula pubescens Decne (LP) is one of the three Lavandula species growing wildly in the Dead Sea Valley, Palestine. The products derived from the plant, including the essential oil (EO), have been used in Traditional Arabic Palestinian Herbal Medicine (TAPHM) for centuries as therapeutic agents. The EO is traditionally believed to have sedative, anti-inflammatory, antiseptic, antidepressive, antiamnesia, and antiobesity properties. This study was therefore aimed to assess the in vitro bioactivities associated with the LP EO. The EO was separated by hydrodistillation from the aerial parts of LP plants and analyzed for its antioxidant, antimicrobial, anticholinesterase, and antilipase activities. GC-MS was used for phytochemical analysis. The chemical analysis of the EO composition revealed 25 constituents, of which carvacrol (65.27%) was the most abundant. EO exhibited strong antioxidant (IC₅₀ 0.16–0.18 μL/mL), antiacetylcholinesterase (IC₅₀ 0.9 μL/mL), antibutyrylcholinesterase (IC₅₀ 6.82 μL/mL), and antilipase (IC₅₀ 1.08 μL/mL) effects. The EO also demonstrated high antibacterial activity with the highest susceptibility observed for Staphylococcus aureus with 95.7% inhibition. The EO was shown to exhibit strong inhibitory activity against Candida albicans (MIC 0.47 μL/mL). The EO was also shown to possess strong antidermatophyte activity against Microsporum canis, Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum (EC₅₀ 0.05–0.06 μL/mL). The high antioxidant, enzyme inhibitory, and antimicrobial potentials of the EO can, therefore, be correlated with its high content of monoterpenes, especially carvacrol, as shown by its comparable bioactivities indicators results. This study provided new insights into the composition and bioactivities of LP EO. Our finding revealed evidence that LP EO makes a valuable natural source of bioactive molecules showing substantial potential as antioxidant, neuroprotective, antihyperlipidemic, and antimicrobial agents. This study demonstrates, for the first time, that LP EO might be useful for further investigation aiming at integrative CAM and clinical applications in the management of dermatophytosis, Alzheimer's disease, and obesity.

The possible role of heat shock protein-70 induction in collagen-induced arthritis in rats

AIM

This study aimed to evaluate the possible role of heat shock protein-70 (HSP70) induction by 17-allylaminodemethoxygeldanamycin (17-AAG) in collagen-induced arthritis in rats.

MATERIAL AND METHODS

Male Wistar rats were divided into five groups (n = 10/group) and were treated intraperitoneally twice a week for 4 weeks, namely normal control (saline), arthritis control (AR; saline), AR + 17-AAG, AR + methotrexate (MTX), and AR + 17-AAG + MTX. At the end of the treatments, arthritic score was determined and then the animals were sacrificed. Erythrocyte sedimentation rate (ESR), serum levels of HSP70, interleukin-17 (IL-17), tumor necrosis factor-alpha (TNF-α), rheumatic factor (RF), C-reactive protein (CRP), malondialdehyde (MDA), glutathione peroxidase (GPx), and matrix metalloproteinase-9 (MMP-9) were determined.

RESULTS

In the AR group, all parameters increased significantly, except for GPx, which showed a pronounced decrease. The 17-AAG and/or MTX treatments significantly reduced arthritic score, ESR, IL-17, TNF-α, RF, CRP, MDA, and MMP-9 with significant increase in GPx compared to the AR group. The HSP70 level was significantly higher in the AR + 17-AAG and the AR + 17-AAG + MTX groups but significantly lower in the AR + MTX group as compared to the AR group. Also, it was significantly lower in the AR + MTX group as compared to the AR + 17-AAG group.

CONCLUSION

We concluded that HSP70 induction by 17-AAG attenuated the inflammatory process in a rheumatoid arthritis (RA) model induced by collagen, which suggested that HSP70 inducers can be promising agents in the treatment of RA.

Heat shock proteins in the therapy of autoimmune diseases: too simple to be true?

Autoimmune diseases are characterized by the loss of immune tolerance to self-antigens which leads to an excessive immune responses and chronic inflammation. Although much progress has been made in revealing key players in pathophysiology of various autoimmune diseases, their therapy remains challenging and consists of conventional immunosuppressive treatments, including corticosteroids and more advanced biological therapies which are targeted at molecules involved in maintaining chronic inflammation. These therapies are focused on suppressing inflammation; nevertheless, a permanent balance between protective and pathogenic immune responses is not achieved. In addition, most of currently available therapies for autoimmune diseases induce severe side effects. Consequently, more effective and safer therapies are still required to control autoimmunity. Stress-induced cell protecting heat shock proteins (HSP) have been considered as a potential treatment targets for autoimmune diseases. HSP, predominantly intracellular components, might be released from bacteria or mammalian tissues and activate immune response. This activation may lead to either production of (auto)antibodies against HSP and/or induction of immune regulatory mechanisms, including expansion of desired T regulatory (Treg) cells. Because inadequate frequency or activity of Treg is a characteristic feature of autoimmune diseases, targeting this cell population is an important focus of immunotherapy approaches in autoimmunity.

Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers

The differences in physiological and immunological parameters and pathological damage to organ tissues exposed to chronic heat stress provide the basis for evaluating heat resistance of different chicken breeds (white recessive rock [WRR] and The Lingshan [LS]). Ninety broilers of each breed were divided equally into a chronic heat stress group and a no heat stress group. The effects of chronic heat stress on the physiological and immunological parameters of broilers were analyzed using flow cytometry, ELISA, RT-qPCR, etc. Under heat stress conditions: (1) H and H/L values were significantly increased (P < 0.01) in the 2 breeds, and were higher in the WRR broilers than in the LS broilers at a late stage (P < 0.05). Although the corticosterone levels were also significantly increased (P < 0.01) in both breeds, they were lower in the 49 d WRR broilers than in the LS broilers (P < 0.01). The number of leukocytes were significantly increased in the 49 d WRR broilers (P < 0.01), whereas the number of CD3+, CD8+ cells, and erythrocytes were significantly reduced (P < 0.05). A significantly (P < 0.01) lower number of CD3+, CD4+ T-lymphocytes, and CD4+/CD8+ were present in WRR compared to that in the LS broilers. (2) The HSP70 transcript was significantly increased in the WRR broilers (P < 0.01), and was higher than the level in the LS broilers. The expression level of HSP70 protein was significantly (P < 0.05) increased in WRR broilers. (3) The WRR broilers developed cardiac and leg muscle inflammatory cellular hyperplasia and local inflammatory lesions, as well as cerebral meningitis and inflammatory hyperplasia of the brain tissue. The LS broilers developed mild cerebral inflammatory hyperplasia and mild inflammatory cellular proliferation in the leg muscle. In conclusion, under heat stress conditions, the relative physiological and immunological parameters were worse in the WRR broilers than in the LS broilers. The WRR broilers showed poor heat tolerance as evidenced from the expression of HSP70 and the extent of histopathological damages.

Regulation of Antimicrobial Pathways by Endogenous Heat Shock Proteins in Gastrointestinal Disorders

Heat shock proteins (HSPs) are essential mediators of cellular homeostasis by maintaining protein functionality and stability, and activating appropriate immune cells. HSP activity is influenced by a variety of factors including diet, microbial stimuli, environment and host immunity. The overexpression and down-regulation of HSPs is associated with various disease phenotypes, including the inflammatory bowel diseases (IBD) such as Crohn’s disease (CD). While the precise etiology of CD remains unclear, many of the putative triggers also influence HSP activity. The development of different CD phenotypes therefore may be a result of the disease-modifying behavior of the environmentally-regulated HSPs. Understanding the role of bacterial and endogenous HSPs in host homeostasis and disease will help elucidate the complex interplay of factors. Furthermore, discerning the function of HSPs in CD may lead to therapeutic developments that better reflect and respond to the gut environment.

The Well-Developed Mucosal Immune Systems of Birds and Mammals Allow for Similar Approaches of Mucosal Vaccination in Both Types of Animals

The mucosal immune system is a compartmentalized part of the immune system that provides local immunity in the mucosa of the respiratory, gastrointestinal, and digestive tracts. It possesses secondary lymphoid tissues, which contain immune cells, such as T, B, and dendritic cells. Once the cells of the mucosal immune system are stimulated by luminal antigens, including microorganisms, they infiltrate into diffuse areas of mucosal tissues (e.g., respiratory mucosa and lamina propria of intestinal villi) and exhibit immune effector functions. Inducing the antigen-specific immune responses in mucosal tissues by mucosal vaccination would be an ideal strategy for not only humans, but also mammals and birds, to protect against infectious diseases occurring in mucosal tissues (e.g., pneumonia and diarrhea). Infectious diseases cause huge economic losses in agriculture, such as livestock and poultry industries. Since most infectious diseases occur in mucosal tissues, vaccines that are capable of inducing immune responses in mucosal tissues are in high need. In this review, we discuss the current understanding of mucosal immunity in mammals and birds, and recent progress in the development of mucosal vaccines.

Immune tolerance therapies for autoimmune diseases based on heat shock protein T-cell epitopes

Experimental models of autoimmune diseases have revealed the disease protective role of heat shock proteins (HSPs). Both the administration of exogenous extracellular, mostly recombinant, HSP and the experimental co-induction of endogenous intracellular HSP in models have been shown to lead to production of disease protective regulatory T cells (Tregs). Similar to HSP taken up from extracellular bodily fluids, due to stress-related autophagy upregulated HSP also from intracellular sources is a major provider for the major histocompatibility class II (MHCII) ligandome; therefore, both extracellular and intracellular HSP can be prominent targets of Treg. The development of therapeutic peptide vaccines for the restoration of immune tolerance in inflammatory diseases is an area of intensive research. In this area, HSPs are a target for tolerance-inducing T-cell therapy, because of their wide expression in inflamed tissues. In humans, in whom the actual disease trigger is frequently unknown, HSP peptides offer chances for tolerance-promoting interventions through induction of HSP-specific Treg. Recently, we have shown the ability of a bacterial HSP70-derived peptide, HSP70-B29, to induce HSP-specific Tregs that suppressed arthritis by cross-recognition of their mammalian HSP70 homologues, abundantly present in the MHCII ligandome of stressed mouse and human antigen-presenting cells in inflamed tissues.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

The Immunomodulatory Potential of tolDCs Loaded with Heat Shock Proteins

Disease suppressive T cell regulation may depend on cognate interactions of regulatory T cells with self-antigens that are abundantly expressed in the inflamed tissues. Heat shock proteins (HSPs) are by their nature upregulated in stressed cells and therefore abundantly present as potential targets for such regulation. HSP immunizations have led to inhibition of experimentally induced inflammatory conditions in various models. However, re-establishment of tolerance in the presence of an ongoing inflammatory process has remained challenging. Since tolerogenic DCs (tolDCs) have the combined capacity of mitigating antigen-specific inflammatory responses and of endowing T cells with regulatory potential, it seems attractive to combine the anti-inflammatory qualities of tolDCs with those of HSPs.

T Cell-Mediated Chronic Inflammatory Diseases Are Candidates for Therapeutic Tolerance Induction with Heat Shock Proteins

Failing immunological tolerance for critical self-antigens is the problem underlying most chronic inflammatory diseases of humans. Despite the success of novel immunosuppressive biological drugs, the so-called biologics, in the treatment of diseases such rheumatoid arthritis (RA) and type 1 diabetes, none of these approaches does lead to a permanent state of medicine free disease remission. Therefore, there is a need for therapies that restore physiological mechanisms of self-tolerance. Heat shock proteins (HSPs) have shown disease suppressive activities in many models of experimental autoimmune diseases through the induction of regulatory T cells (Tregs). Also in first clinical trials with HSP-based peptides in RA and diabetes, the induction of Tregs was noted. Due to their exceptionally high degree of evolutionary conservation, HSP protein sequences (peptides) are shared between the microbiota-associated bacterial species and the self-HSP in the tissues. Therefore, Treg mechanisms, such as those induced and maintained by gut mucosal tolerance for the microbiota, can play a role by targeting the more conserved HSP peptide sequences in the inflamed tissues. In addition, the stress upregulated presence of HSP in these tissues may well assist the targeting of the HSP induced Treg specifically to the sites of inflammation.

Targeting of tolerogenic dendritic cells towards heat-shock proteins: a novel therapeutic strategy for autoimmune diseases?

Tolerogenic dendritic cells (tolDCs) are a promising therapeutic tool to restore immune tolerance in autoimmune diseases. The rationale of using tolDCs is that they can specifically target the pathogenic T-cell response while leaving other, protective, T-cell responses intact. Several ways of generating therapeutic tolDCs have been described, but whether these tolDCs should be loaded with autoantigen(s), and if so, with which autoantigen(s), remains unclear. Autoimmune diseases, such as rheumatoid arthritis, are not commonly defined by a single, universal, autoantigen. A possible solution is to use surrogate autoantigens for loading of tolDCs. We propose that heat-shock proteins may be a relevant surrogate antigen, as they are evolutionarily conserved between species, ubiquitously expressed in inflamed tissues and have been shown to induce regulatory T cells, ameliorating disease in various arthritis mouse models. In this review, we provide an overview on how immune tolerance may be restored by tolDCs, the problem of selecting relevant autoantigens for loading of tolDCs, and why heat-shock proteins could be used as surrogate autoantigens.

Carvacrol promotes angiogenic paracrine potential and endothelial differentiation of human mesenchymal stem cells at low concentrations

OBJECTIVES

Phenolic monoterpene compound, named Carvacrol, has been found to exert different biological outcomes. It has been accepted that the angiogenic activity of human mesenchymal stem cells was crucial in the pursuit of appropriate regeneration. In the current experiment, we investigated the contribution of Carvacrol on the angiogenic behavior of primary human mesenchymal stem cells.

METHODS

Mesenchymal stem cells were exposed to Carvacrol in a dose ranging from 25 to 200μM for 48h. We measured cell survival rate by MTT assay and migration rate by a scratch test. The oxidative status was monitored by measuring SOD, GPx activity. The endothelial differentiation was studied by evaluating the level of VE-cadherin and vWF by real-time PCR and ELISA analyses. The content of VEGF and tubulogenesis behavior was monitored in vitro. We also conducted Matrigel plug in vivo CAM assay to assess the angiogenic potential of conditioned media from human mesenchymal stem cells after exposure to Carvacrol.

RESULTS

Carvacrol was able to increase mesenchymal stem cell survival and migration rate (p<0.05). An increased activity of SOD was obtained while GPx activity unchanged or reduced. We confirmed the endothelial differentiation of stem cells by detecting vWF and VE-cadherin expression (p<0.05). The VEGF expression was increased and mesenchymal stem cells conditioned media improved angiogenesis tube formation in vitro (p<0.05). Moreover, histological analysis revealed an enhanced microvascular density at the site of Matrigel plug in CAM assay.

CONCLUSIONS

Our data shed lights on the possibility of a Carvacrol to induce angiogenesis in human mesenchymal stem cells by modulating cell differentiation and paracrine angiogenic response.

Highly Selective Activation of Heat Shock Protein 70 by Allosteric Regulation Provides an Insight into Efficient Neuroinflammation Inhibition

Heat shock protein 70 (Hsp70) is widely involved in immune disorders, making it as an attractive drug target for inflammation diseases. Nonselective induction of Hsp70 upregulation for inflammation therapy could cause extensive interference in inflammation-unrelated protein functions, potentially resulting in side effects. Nevertheless, direct pharmacological activation of Hsp70 via targeting specific functional amino acid residue may provide an insight into precise Hsp70 function regulation and a more satisfactory treatment effect for inflammation, which has not been extensively focused. Here we show a cysteine residue (Cys306) for selective Hsp70 activation using natural small-molecule handelin. Covalent modification of Cys306 significantly elevates Hsp70 activity and shows more satisfactory anti-neuroinflammation effects. Mechanism study reveals Cys306 modification by handelin induces an allosteric regulation to facilitate adenosine triphosphate hydrolysis capacity of Hsp70, which leads to the effective blockage of subsequent inflammation signaling pathway. Collectively, our study offers some insights into direct pharmacological activation of Hsp70 by specially targeting functional cysteine residue, thus providing a powerful tool for accurately modulating neuroinflammation pathogenesis in human with fewer undesirable adverse effects.

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Cys306 is a druggable residue for direct pharmacological activation of Hsp70.

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Covalent modification of Cys306 promotes direct Hsp70 activation via allosteric effect.

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Pharmacological activation of Hsp70 exerts satisfactory inhibition on neuroinflammation with fewer side effects.

Accumulated evidence reveals that Hsp70, a stress response protein, is highly involved in various neuroimmunological diseases. Hsp70 herein serves as a tempting target for anti-inflammation therapy. In this work, we identified an herb-derived guaianolide dimer compound handelin as a potent activator of Hsp70 with anti-neuroinflammatory effects. Handelin covalently modified Cys306 residue of Hsp70, and then activated Hsp70 by allosteric effect. These results can provide an insight into the direct pharmacological regulation of Hsp70 function by targeting specific amino acid residue and also guide future rational drug design to treat human neuroimmunological diseases.

Enhanced resistance against Vibrio harveyi infection by carvacrol and its association with the induction of heat shock protein 72 in gnotobiotic Artemia franciscana

Induction of HSP72 is a natural response of stressed organisms that protects against many insults including bacterial diseases in farm (aquatic) animals. It would therefore be of great health benefit to search for natural compounds that are clinically safe yet able to induce HSP72 in animals. The phenolic compound carvacrol, an approved food component, had been shown in in vitro study to act as a co-inducer of HSP72, enhancing HSP72 production only in combination with a bona fide stress compared to the compound alone. However, in vitro model systems do not completely represent an in vivo physiology. Here, using the well-established gnotobiotic Artemia model system, we determined whether carvacrol could induce HSP72 in vivo, whether this putative effect could generate resistance in Artemia against biotic/abiotic stress and also unraveled the mechanism behind the possible HSP72-inducing effect of carvacrol. The gnotobiotic system is crucial for such studies because it avoids the interference of any extraneous factors on host-compound interaction. Here, carvacrol was shown to be a potent HSP72 inducer. Induction of HSP72 was associated with the generation of resistance in Artemia larvae against subsequent lethal heat stress or pathogenic Vibrio harveyi. Our results also provided new insight on the mode of HSP72 inducing action of carvacrol, in which the initial generation of reactive molecule H2O2 by the compound plays a key role. Overall results add new information about the bioactivity of carvacrol and advance our knowledge of this compound as potential prophylactic agent for controlling Vibrio infection in aquaculture animals.

Expression of Hsp70 reveals significant differences between fin regeneration and inflammation in Paramisgurnus dabryanus

Hsp70 is the most strongly induced in response to various cellular stresses and a good candidate for investigating its role in tissue injury. We firstly cloned full-length cDNA of hsp70 from Paramisgurnus dabryanus (PdHsp70) by RACE method (GenBank: KP402408.1). Then regeneration and inflammation of fin were established by amputation and scratch respectively. Quantitative RT-PCR detected the PdHsp70 began to increase rapidly its expression at 1 days post amputation (dpa) and reached the peak at 2 dpa during fin regeneration. Its expression was also up-regulated at 2 days post scratch (dps) of inflammation but still significant weaker in comparison with it in regenerated fin at 2 dpa. Next, immunohistochemistry analysis of PdHsp70 showed that PdHsp70 located mainly in the deeper epidermis of regenerated fin and was stronger than its expression in the scratched inflammatory fin which was involved in whole epidermal. SDS-PAGE and Western blotting confirmed that the PdHsp70 protein expressed efficiently in Escherichia coli BL21. These findings have implied that PdHsp70 are implicated in different regulation of regeneration and inflammation in response to injury stimulation. During the regeneration, it is involved in the formation of wound epidermis by mediating cellular protection whereas it can modulate inflammatory by activating the innate immune response.

Unconventional Secretion of Heat Shock Proteins in Cancer

Heat shock proteins (HSPs) are abundant cellular proteins involved with protein homeostasis. They have both constitutive and inducible isoforms, whose expression levels are further increased by stress conditions, such as temperature elevation, reduced oxygen levels, infection, inflammation and exposure to toxic substances. In these situations, HSPs exert a pivotal role in offering protection, preventing cell death and promoting cell recovery. Although the majority of HSPs functions are exerted in the cytoplasm and organelles, several lines of evidence reveal that HSPs are able to induce cell responses in the extracellular milieu. HSPs do not possess secretion signal peptides, and their secretion was subject to widespread skepticism until the demonstration of the role of unconventional secretion forms such as exosomes. Secretion of HSPs may confer immune system modulation and be a cell-to-cell mediated form of increasing stress resistance. Thus, there is a wide potential for secreted HSPs in resistance of cancer therapy and in the development new therapeutic strategies.

Cinnamaldehyde, Carvacrol and Organic Acids Affect Gene Expression of Selected Oxidative Stress and Inflammation Markers in IPEC-J2 Cells Exposed to Salmonella typhimurium

Essential oils and organic acids are used as feed additives to improve health status and reduce colonization with pathogens. Although bactericidal in vitro, concentrations achieved in the animal gut are probably not lethal to pathogens. The aim of this study was to investigate the effects of cinnamaldehyde, carvacrol and cinnamic, lactic and propionic acids on the ability of Salmonella typhimurium ATCC 14028 (ST) to invade intestinal epithelial cells (IPEC-J2) and on the expression levels of immune related genes in the cells. The minimum inhibitory concentration (MIC) and non-inhibitory concentration (NIC) were determined and influence on the invasion capacity of ST was investigated. The structure of fimbriae and flagella was analysed by electron microscopy, and expression levels of HSP70, IkBa, IL-8 and IL-10 in the IPEC-J2 cells were carried out by q-PCR. Cinnamaldehyde, carvacrol and cinnamic and propionic acids inhibited ST invasion but not cell viability, bacterial viability and motility or the development of flagella. Propionic acid and cinnamaldehyde in combination with cinnamic acid caused structural impairment of fimbriae. Cinnamaldehyde up-regulated expression of HSP70 irrespective of the presence of organic acids or ST; exposure to carvacrol induced HSP70 only in the presence of propionic acid and ST. © 2016 The Authors. Phytotherapy Research published by John Wiley & Sons Ltd.

The kinetics of damage-associated molecular patterns (DAMPs) and toll-like receptors during thioacetamide-induced acute liver injury in rats

Drug-induced liver injury (DILI) is a common problem in human medicine and it is a major reason to withdraw marketed drugs. However, the mechanism of DILI is still less known. Damage-associated molecular patterns (DAMPs), such as high-mobility group boxes (HMGBs), S100 proteins and heat shock proteins (HSPs), are released from injured or necrotic cells, bind to toll-like receptors (TLRs) and modulate inflammatory reactions. Here we investigated the kinetics of DAMPs, TLRs and MHC class II in a rat model of DILI with thioacetamide (TAA). After TAA administration, extensive necrosis was observed on days 1 and 2, followed by infiltration of inflammatory cells on day 3. The levels of serum liver enzymes also peaked on day 1. Expression of HMGB-1, -2 and S100A4 peaked on day 2. TLR-4 was up-regulated on day 3. The number of MHC class II-positive macrophages increased until day 2. These results suggest that HMGB-1, -2 and S100A4 are associated with hepatocellular necrosis and that DAMPs may activate TLR-4 and MHC class II during TAA-induced liver injury. Our data would contribute to the elucidation of the mechanism of DILI.

T cell epitope redundancy: cross-conservation of the TCR face between pathogens and self and its implications for vaccines and autoimmunity

T cells are extensively trained on 'self' in the thymus and then move to the periphery, where they seek out and destroy infections and regulate immune response to self-antigens. T cell receptors (TCRs) on T cells' surface recognize T cell epitopes, short linear strings of amino acids presented by antigen-presenting cells. Some of these epitopes activate T effectors, while others activate regulatory T cells. It was recently discovered that T cell epitopes that are highly conserved on their TCR face with human genome sequences are often associated with T cells that regulate immune response. These TCR-cross-conserved or 'redundant epitopes' are more common in proteins found in pathogens that have co-evolved with humans than in other non-commensal pathogens. Epitope redundancy might be the link between pathogens and autoimmune disease. This article reviews recently published data and addresses epitope redundancy, the "elephant in the room" for vaccine developers and T cell immunologists.

Stem cell-derived tissue-associated regulatory T cells ameliorate the development of autoimmunity

Pluripotent stem cells (PSCs) have the potential to produce almost all of the cells in the body, including regulatory T cells (T_regs). However, the exact conditions required for the development of antigen (Ag)-specific T_regs from PSCs (i.e., PSC-T_regs) are not well delineated. Ag-specific PSC-T_regs can be tissue/organ-associated and migrate to local inflamed tissues/organs to suppress the autoimmune response after adoptive transfer, thereby avoiding potential overall immunosuppression from non-specific T_regs. In this study, we developed a new approach to generate functional Ag-specific T_regs from induced PSCs (iPSCs), i.e., iPSC-T_regs, which had the ability to generate an Ag-specific immunosuppressive response in a murine model of arthritis. We retrovirally transduced murine iPSCs with a construct containing genes of Ag-specific T cell receptor (TCR) and the transcriptional factor FoxP3. We differentiated the iPSCs into Ag-specific iPSC-T_regs using in vitro or in vivo Notch signaling, and demonstrated that adoptive transfer of such T_regs dramatically suppressed autoimmunity in a well-established Ag-induced arthritis model, including the inflammation, joint destruction, cartilage prostaglandin depletion, osteoclast activity, and Th17 production. Our results indicate that PSCs can be used to develop Ag-specific T_regs, which have a therapeutic potential for T_reg-based therapies of autoimmune disorders.

Clematichinenoside AR induces immunosuppression involving Treg cells in Peyer׳s patches of rats with adjuvant induced arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Clematichinenoside AR (AR) has been defined as a major active ingredient of triterpenoid saponins extracted from Clematidis Radix et Rhizoma, which is a traditional Chinese herbal medicine that has long been used in the treatment of rheumatoid arthritis (RA). To further explore the mechanism of AR in the treatment of RA, we investigated whether its immunomodulatory effects are related to Treg-mediated suppression derived from Peyer׳s patches (PPs) in adjuvant induced arthritis (AIA) rat model.

MATERIALS AND METHODS

AR (8, 16, 32 mg/kg) was orally administered daily from Day 18 to Day 31 after immunization. The effect of AR on AIA rats was evaluated by hind paw swelling and histopathological examination. Percentages of CD4(+)CD25(+)Foxp3(+) T regulatory cells were determined by flow cytometry. Levels of IL-10, TGF-β1, IL-17A and TNF-α were measured by ELISA. Expressions of Foxp3 and RORγ in synovium were detected using immunohistochemical analysis.

RESULTS

AR treatment significantly reduced paw swelling of AIA rats, and histopathological analysis confirmed it could suppress severity of established arthritis. AR treatment upregulated the percentages of CD4(+)CD25(+)Foxp3(+) Treg cells among CD4+ T cells in PPs lymphocytes, and increased the levels of IL-10 and TGF-β1 secreted from ConA-activated PPs lymphocytes, whereas decreased the levels of IL-17 A and TNF-α. Similar tendency of circulating CD4(+)CD25(+)Foxp3(+) Treg cells percentages and serum cytokine levels were observed. Moreover, AR decreased the expression levels of Foxp3 and RORγ in joint synovial membrane.

CONCLUSIONS

In conclusion, these results suggested AR has a potent protective effect on the progression of AIA, probably by augmenting CD4(+)CD25(+)Foxp3(+) Treg cells in PPs to induce immunosuppression, and modulating the balance between Treg cells and Th17 cells systemically. These findings may help to develop AR as a potent immunosuppressive agent for the treatment of RA.

T cell recognition of naturally presented epitopes of self-heat shock protein 70

Self-reactive T cells have shown to have a potential role as regulators of the immune system preventing or even suppressing autoimmunity. One of the most abundant proteins that can be eluted from human HLA molecules is heat shock protein 70 (HSP70). The aims of the current study are to identify HSP70 epitopes based on published HLA elution studies and to investigate whether T cells from healthy individuals may respond to such self-epitopes. A literature search and subsequent in silico binding prediction based on theoretical MHC binding motifs resulted in the identification of seven HSP70 epitopes. PBMCs of healthy controls proliferated after incubation with two of the seven peptides (H167 and H290). Furthermore H161, H290, and H443 induced CD69 expression or production of cytokines IFNγ or TNFα in healthy controls. The identification of these naturally presented epitopes and the response they elicit in the normal immune system make them potential candidates to study during inflammatory conditions as well as in autoimmune diseases.

The importance of the cellular stress response in the pathogenesis and treatment of type 2 diabetes

Organisms have evolved to survive rigorous environments and are not prepared to thrive in a world of caloric excess and sedentary behavior. A realization that physical exercise (or lack of it) plays a pivotal role in both the pathogenesis and therapy of type 2 diabetes mellitus (t2DM) has led to the provocative concept of therapeutic exercise mimetics. A decade ago, we attempted to simulate the beneficial effects of exercise by treating t2DM patients with 3 weeks of daily hyperthermia, induced by hot tub immersion. The short-term intervention had remarkable success, with a 1 % drop in HbA1, a trend toward weight loss, and improvement in diabetic neuropathic symptoms. An explanation for the beneficial effects of exercise and hyperthermia centers upon their ability to induce the cellular stress response (the heat shock response) and restore cellular homeostasis. Impaired stress response precedes major metabolic defects associated with t2DM and may be a near seminal event in the pathogenesis of the disease, tipping the balance from health into disease. Heat shock protein inducers share metabolic pathways associated with exercise with activation of AMPK, PGC1-a, and sirtuins. Diabetic therapies that induce the stress response, whether via heat, bioactive compounds, or genetic manipulation, improve or prevent all of the morbidities and comorbidities associated with the disease. The agents reduce insulin resistance, inflammatory cytokines, visceral adiposity, and body weight while increasing mitochondrial activity, normalizing membrane structure and lipid composition, and preserving organ function. Therapies restoring the stress response can re-tip the balance from disease into health and address the multifaceted defects associated with the disease.

Immunomodulation in human and experimental arthritis: including vitamin D, helminths and heat-shock proteins

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that is mainly directed to the joints, affecting the synovial membrane, the cartilage and also the bone. This disease affects 1% to 2% of the world population and is associated with significant morbidity and increased mortality. RA experimental models have allowed a great deal of information to be translated to the corresponding human disease. This review summarizes some of the most relevant findings targeting immunomodulation in arthritis. Some general guidelines to choose an adequate experimental model and also our experience with arthritis are supplied.

Heat Shock Proteins: Intestinal Gatekeepers that Are Influenced by Dietary Components and the Gut Microbiota

Trillions of microorganisms that inhabit the intestinal tract form a diverse and intricate ecosystem with a deeply embedded symbiotic relationship with their hosts. As more detailed information on gut microbiota complexity and functional diversity accumulates, we are learning more about how diet-microbiota interactions can influence the immune system within and outside the gut and host health in general. Heat shock proteins are a set of highly conserved proteins that are present in all types of cells, from microbes to mammals. These proteins carry out crucial intracellular housekeeping functions and unexpected extracellular immuno-regulatory features in order to maintain the mucosal barrier integrity and gut homeostasis. It is becoming evident that the enteric microbiota is one of the major determinants of heat shock protein production in intestinal epithelial cells. This review will focus on the interactions between diet, gut microbiota and their role for regulating heat shock protein production and, furthermore, how these interactions influence the immune system and the integrity of the mucosal barrier.

Regulation of macrophage and dendritic cell function by pathogens and through immunomodulation in the avian mucosa

Macrophages (MPh) and dendritic cells (DC) are members of the mononuclear phagocyte system. In chickens, markers to distinguish MPh from DC are lacking, but whether MPh and DC can be distinguished in humans and mice is under debate, despite the availability of numerous markers. Mucosal MPh and DC are strategically located to ingest foreign antigens, suggesting they can rapidly respond to invading pathogens. This review addresses our current understanding of DC and MPh function, the receptors expressed by MPh and DC involved in pathogen recognition, and the responses of DC and MPh against respiratory and intestinal pathogens in the chicken. Furthermore, potential opportunities are described to modulate MPh and DC responses to enhance disease resistance, highlighting modulation through nutraceuticals and vaccination.

Bacille Calmette-Guérin/DNAhsp65 prime-boost is protective against diabetes in non-obese diabetic mice but not in the streptozotocin model of type 1 diabetes

Type I diabetes is a disease caused by autoimmune destruction of the beta cells in the pancreas that leads to a deficiency in insulin production. The aim of this study was to evaluate the prophylactic potential of a prime-boost strategy involving bacille Calmette-Guérin (BCG) and the pVAXhsp65 vaccine (BCG/DNAhsp65) in diabetes induced by streptozotocin (STZ) in C57BL/6 mice and also in spontaneous type 1 diabetes in non-obese diabetic (NOD) mice. BCG/DNAhsp65 vaccination in NOD mice determined weight gain, protection against hyperglycaemia, decreased islet inflammation, higher levels of cytokine production by the spleen and a reduced number of regulatory T cells in the spleen compared with non-immunized NOD mice. In the STZ model, however, there was no significant difference in the clinical parameters. Although this vaccination strategy did not protect mice in the STZ model, it was very effective in NOD mice. This is the first report demonstrating that a prime-boost strategy could be explored as an immunomodulatory procedure in autoimmune diseases.

Human Hsp40 proteins, DNAJA1 and DNAJA2, as potential targets of the immune response triggered by bacterial DnaJ in rheumatoid arthritis

Hsp40 proteins of bacterial and human origin are suspected to be involved in the pathogenesis of rheumatoid arthritis (RA). It has been shown that sera of RA patients contain increased levels of antibodies directed to bacterial and human Hsp40s. The aim of this work was to explore immunological similarities between the bacterial (DnaJ) and human (DNAJA1 and DNAJA2) Hsp40 proteins in relation to their possible involvement in the RA. Using polyclonal antibodies directed against a full-length DnaJ or its domains, against DNAJA1 and DNAJA2, as well as monoclonal anti-DnaJ antibodies, we found immunological similarities between the bacterial and human Hsp40s. Both ELISA and Western blotting showed that these similarities were not restricted to the conserved J domains but were also present in the C-terminal variable regions. We also found a positive correlation between the levels of the anti-DnaJ and anti-DNAJA1 antibodies in the sera of RA patients. This finding supports the molecular mimicry hypothesis that human Hsp40 could be the targets of antibodies originally directed against bacterial DnaJ in RA.

Gut microbiota imbalance and chaperoning system malfunction are central to ulcerative colitis pathogenesis and can be counteracted with specifically designed probiotics: a working hypothesis

In this work, we propose that for further studies of the physiopathology and treatment for inflammatory bowel diseases, an integral view of the conditions, including the triad of microbiota-heat shock proteins (HSPs)-probiotics, ought to be considered. Microbiota is the complex microbial flora that resides in the gut, affecting not only gut functions but also the health status of the whole body. Alteration in the microbiota's composition has been implicated in a variety of pathological conditions (e.g., ulcerative colitis, UC), involving both gut and extra-intestinal tissues and organs. Some of these pathologies are also associated with an altered expression of HSPs (chaperones) and this is the reason why they may be considered chaperonopathies. Probiotics, which are live microorganisms able to restore the correct, healthy equilibrium of microbiota composition, can ameliorate symptoms in patients suffering from UC and modulate expression levels of HSPs. However, currently probiotic therapy follows ex-adiuvantibus criteria, i.e., treatments with beneficial effects but whose mechanism of action is unknown, which should be changed so the probiotics needed in each case are predetermined on the basis of the patient's microbiota. Consequently, efforts are necessary to develop diagnostic tools for elucidating levels and distribution of HSPs and the microbiota composition (microbiota fingerprint) of each subject and, thus, guide specific probiotic therapy, tailored to meet the needs of the patient. Microbiota fingerprinting ought to include molecular biology techniques for sequencing highly conserved DNA, e.g., genes encoding 16S RNA, for species identification and, in addition, quantification of each relevant microbe.