Immunomodulatory effect of resistin in human dendritic cells stimulated with lipoteichoic acid from Staphylococcus aureus

Multi-omics analysis reveals a feedback loop amplifying immune responses in acute graft-versus-host disease due to imbalanced gut microbiota and bile acid metabolism

Acute graft-versus-host disease (aGVHD) is primarily driven by allogeneic donor T cells associated with an altered composition of the host gut microbiome and its metabolites. The severity of aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is not solely determined by the host and donor characteristics; however, the underlying mechanisms remain unclear. Using single-cell RNA sequencing, we decoded the immune cell atlas of 12 patients who underwent allo-HSCT: six with aGVHD and six with non-aGVHD. We performed a fecal microbiota (16SrRNA sequencing) analysis to investigate the fecal bacterial composition of 82 patients: 30 with aGVHD and 52 with non-aGVHD. Fecal samples from these patients were analyzed for bile acid metabolism. Through multi-omic analysis, we identified a feedback loop involving "immune cell-gut microbes-bile acid metabolites" contributing to heightened immune responses in patients with aGVHD. The dysbiosis of the gut microbiota and disruption of bile acid metabolism contributed to an exaggerated interleukin-1 mediated immune response. Our findings suggest that resistin and defensins are crucial in mitigating against aGVHD. Therefore, a comprehensive multi-omic atlas incorporating immune cells, gut microbes, and bile acid metabolites was developed in this study and used to propose novel, non-immunosuppressive approaches to prevent aGVHD.

The infrapatellar fat pad in inflammaging, knee joint health, and osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis and accounts for nearly $140 billion in annual healthcare expenditures only in the United States. Obesity, aging, and joint injury are major risk factors for OA development and progression, but the mechanisms contributing to pathology remain unclear. Emerging evidence suggests that cellular dysregulation and inflammation in joint tissues, including intra-articular adipose tissue depots, may contribute to disease severity. In particular, the infrapatellar fat pad (IFP), located in the knee joint, which provides a protective cushion for joint loading, also secretes multiple endocrine factors and inflammatory cytokines (inflammaging) that can regulate joint physiology and disease. Correlates of cartilage degeneration and OA-associated disease severity include inflammation and fibrosis of IFP in model organisms and human studies. In this article, we discuss recent progress in understanding the roles and regulation of intra-articular fat tissue in regulating joint biology and OA.

The role of adipokines in the pathogenesis of psoriasis - a focus on resistin, omentin-1 and vaspin

BACKGROUND

Psoriasis is a chronic immune-mediated skin condition with several types of manifestation, including psoriatic arthritis. In recent years, studies have demonstrated multiple molecules and mechanisms that play important roles in the pathophysiology of psoriasis. Studies have been conducted to determine the role of adipokines, bioactive peptides secreted by the adipose tissue, in the pathogenesis of inflammatory diseases. These studies have shown that adipokines are dysregulated in psoriasis and their abnormal expression profile could contribute to the inflammatory mechanisms observed in psoriasis.

AREAS COVERED

In this review, we discuss the immunomodulatory features of resistin, omentin-1, and vaspin, and discuss their potential involvement in the pathogenesis of psoriasis.

EXPERT OPINION

The adipokines resistin, omentin, and vaspin appear to be promising therapeutic targets in psoriasis. It is important to seek to block the action of resistin, either by blocking its receptors or by blocking its systemic effects with antibodies. In the case of omentin and vaspin, substances that are receptor mimetics of these adipokines should be sought and studies conducted of their analogues for the treatment of psoriasis. To introduce these therapies into clinical practice, multicentre clinical trials are required to confirm their efficacy and safety after initial studies in animal models.

Resistin - A Plausible Therapeutic Target in the Pathogenesis of Psoriasis

Resistin, a cytokine hormone predominantly secreted by adipose tissue, is elevated in various metabolic disorders such as obesity, type 2 diabetes, and cardiovascular disease. In addition to its involvement in metabolic regulation, resistin has been implicated in the pathogenesis of psoriasis, a chronic inflammatory skin disorder. Numerous studies have reported increased resistin levels in psoriatic skin lesions, suggesting a possible association between resistin and psoriasis. Recent studies have suggested the potential involvement of resistin in the development and progression of certain cancers. Resistin is overexpressed in breast, colorectal, and gastric cancers. This suggests that it may play a role in the development of these cancers, possibly by inducing inflammation and cell growth. The link between resistin and cancer raises the possibility of shared underlying mechanisms driving the pathogenesis of psoriasis. Chronic inflammation, one such mechanism, is a hallmark of psoriasis and cancer. Further research is needed to fully understand the relationship between resistin and psoriasis. Identifying potential therapeutic targets is crucial for effective management of psoriasis. By doing so, we may be able to develop more effective treatment options for individuals living with psoriasis and ultimately improve their quality of life. Ultimately, a more comprehensive understanding of the mechanisms underlying the impact of resistin on psoriasis is essential for advancing our knowledge and finding new ways to treat and manage this challenging condition.

Adipokines in atopic dermatitis: the link between obesity and atopic dermatitis

Atopic dermatitis (AD) is a chronic skin condition with intense pruritus, eczema, and dry skin. The recurrent intense pruritus and numerous complications in patients with AD can profoundly affect their quality of life. Obesity is one of its comorbidities that has been confirmed to be the hazard factor of AD and also worsen its severity. Nevertheless, the specific mechanisms that explain the connection between obesity and AD remain incompletely recognized. Recent studies have built hopes on various adipokines to explain this connection. Adipokines, which are disturbed by an obese state, may lead to immune system imbalances in people with AD and promote the development of the disease. This review focuses on the abnormal expression patterns of adipokines in patients with AD and their potential regulatory molecular mechanisms associated with AD. The connection between AD and obesity is elucidated through the involvement of adipokines. This conduces to the in-depth exploration of AD pathogenesis and provides a new perspective to develop therapeutic targets.

Resistin, a Novel Host Defense Peptide of Innate Immunity

Resistin, a cysteine-rich protein, expressed in adipocytes, was initially proposed as a link between obesity and diabetes in mice. In humans, resistin is considered to be a pro-inflammatory molecule expressed in immune cells, which plays a regulatory role in many chronic inflammatory diseases, metabolic diseases, infectious diseases, and cancers. However, increasing evidence shows that resistin functions as a host defense peptide of innate immunity, in terms of its wide-spectrum anti-microbial activity, modulation of immunity, and limitation of microbial product-induced inflammation. To date, the understanding of resistin participating in host defense mechanism is still limited. The review aims to summarize current knowledge about the biological properties, functions, and related mechanisms of resistin in host defense, which provides new insights into the pleiotropic biological function of resistin and yields promising strategies for developing new antimicrobial therapeutic agents.

The complex role of adipokines in obesity, inflammation, and autoimmunity

The global obesity epidemic is a major contributor to chronic disease and disability in the world today. Since the discovery of leptin in 1994, a multitude of studies have characterized the pathological changes that occur within adipose tissue in the obese state. One significant change is the dysregulation of adipokine production. Adipokines are an indispensable link between metabolism and optimal immune system function; however, their dysregulation in obesity contributes to chronic low-grade inflammation and disease pathology. Herein, I will highlight current knowledge on adipokine structure and physiological function, and focus on the known roles of these factors in the modulation of the immune response. I will also discuss adipokines in rheumatic and autoimmune diseases.

Resistin in metabolism, inflammation, and disease

Resistin is a small secretory protein that has a pleiotropic role in rodents and humans. Both rodent resistin and human resistin have an extremely stable and high-order multimeric structure. Moreover, there is significant variation in the source of secretion and the diversity of functions of resistin. Mouse resistin resists insulin action and contributes to type 2 diabetes mellitus, while human resistin plays a role in inflammation and also functions as a small accessory chaperone. Currently, active research in the area identified a significant role for resistin in stress biology and as a biomarker in diagnostics to evaluate disease status and treatment outcome. This review summarizes recent developments within resistin biology including their association with obesity, inflammation, stress response mechanisms, and its role in clinical diagnostics.

The impact of metabolic reprogramming on dendritic cell function

Dendritic cells (DCs) are antigen-presenting cells with the ability to activate naïve T cells and direct the adaptive cellular immune response toward a specific profile. This is important, as different pathogens demand specific "profiles" of immune responses for their elimination. Such a goal is achieved depending on the maturation/activation status of DCs by the time of antigen presentation to T cells. Notwithstanding this, recent studies have shown that DCs alter their metabolic program to accommodate the functional changes in gene expression and protein synthesis that follow antigen recognition. In this review, we aim to summarize the data in the literature regarding the metabolic pathways involved with DC phenotypes and their functions.

Age-Associated Decline in Dendritic Cell Function and the Impact of Mediterranean Diet Intervention in Elderly Subjects

INTRODUCTION

Aging is accompanied by increased susceptibility to infection and age-associated chronic diseases. It is also associated with reduced vaccine responses, which is often attributed to immunosenescence and the functional decline of the immune system. Immunosenescence is characterized by a chronic, low-grade, inflammatory state termed inflammaging. Habitants of Mediterranean (MED) regions maintain good health into old age; often attributed to MED diets.

HYPOTHESIS

Adoption of a MED-diet by elderly subjects, in Norfolk (UK), may improve immune responses of these individuals and in particular, dendritic cell (DC) function.

EXPERIMENTAL APPROACH

A total of 120 elderly subjects (65-79 years old) recruited onto the Nu-AGE study, a multicenter European dietary study specifically addressing the needs of the elderly, across five countries, and were randomized to the control or MED-diet groups, for one year. Blood samples were taken pre- and post-intervention for DC analysis and were compared with each other, and to samples obtained from 45 young (18-40 years old) subjects. MED-diet compliance was assessed using high performance liquid chromatography-with tandem mass spectrometry analysis of urine samples. Immune cell and DC subset numbers and concentrations of secreted proteins were determined by flow cytometric analysis.

RESULTS

As expected, reduced myeloid DC numbers were observed in blood samples from elderly subjects compared with young. The elevated secretion of the adipokine, resistin, after ex vivo stimulation of peripheral blood mononuclear cells from elderly subjects, was significantly reduced after MED-diet intervention.

CONCLUSION

This study provides further evidence of numerical and functional effects of aging on DCs. The MED-diet showed potential to impact on the aging immune cells investigated and could provide an economical approach to address problems associated with our aging population.

Ginsenoside fractions regulate the action of monocytes and their differentiation into dendritic cells

Background

Panax ginseng (i.e., ginseng) root is extensively used in traditional oriental medicine. It is a modern pharmaceutical reagent for preventing various human diseases such as cancer. Ginsenosides—the major active components of ginseng—exhibit immunomodulatory effects. However, the mechanism and function underlying such effects are not fully elucidated, especially in human monocytes and dendritic cells (DCs).

Methods

We investigated the immunomodulatory effect of ginsenosides from Panax ginseng root on CD14⁺ monocytes purified from human adult peripheral blood mononuclear cells (PBMCs) and on their differentiation into DCs that affect CD4⁺ T cell activity.

Results

After treatment with ginsenoside fractions, monocyte levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 increased through phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and c-Jun N-terminal kinase (JNK), but not p38 mitogen-activated protein kinase (MAPK). After treatment with ginsenoside fractions, TNF-α production and phosphorylation of ERK1/2 and JNK decreased in lipopolysaccharide (LPS)-sensitized monocytes. We confirmed that DCs derived from CD14⁺ monocytes in the presence of ginsenoside fractions (Gin-DCs) contained decreased levels of the costimulatory molecules CD80 and CD86. The expression of these costimulatory molecules decreased in LPS-treated DCs exposed to ginsenoside fractions, compared to their expression in LPS-treated DCs in the absence of ginsenoside fractions. Furthermore, LPS-treated Gin-DCs could not induce proliferation and interferon gamma (IFN-γ) production by CD4⁺ T cells with the coculture of Gin-DCs with CD4+ T cells.

Conclusion

These results suggest that ginsenoside fractions from the ginseng root suppress cytokine production and maturation of LPS-treated DCs and downregulate CD4⁺ T cells.

Targeted mass spectrometry analysis of neutrophil-derived proteins released during sepsis progression

Early diagnosis of severe infectious diseases is essential for timely implementation of lifesaving therapies. In a search for novel biomarkers in sepsis diagnosis we focused on polymorphonuclear neutrophils (PMNs). Notably, PMNs have their protein cargo readily stored in granules and following systemic stimulation, an immediate increase of neutrophil-borne proteins can be observed into the circulation of sepsis patients. We applied a combination of mass spectrometry (MS) based approaches, LC-MS/MS and selected reaction monitoring (SRM), to characterise and quantify the neutrophil proteome in healthy or disease conditions. With this approach we identified a neutrophil-derived protein abundance pattern in blood plasma consisting of 20 proteins that can be used as a protein signature for severe infectious diseases. Our results also show that SRM is highly sensitive, specific, and reproducible and, thus, a promising technology to study a complex, dynamic and multifactorial disease such as sepsis.

Survival of porcine fibroblasts enhanced by human FasL and dexamethasone-treated human dendritic cells in vitro

Cell-mediated and acute vascular rejections remain to be one of the primary hurdles to achieve successful xenotransplantation. Fas ligand is known to be an important molecule for the formation of 'immune-privileged' condition and dendritic cells treated with dexamethasone (Dex-DCs) acting like tolerogenic DCs (tDCs) which are known to protect transplanted cells and organs from unwanted immune responses. The present study investigated the possibility that porcine fibroblasts expressing human Fas ligand (PhF) together with human Dex-DCs could induce prolonged survival of porcine fibroblasts in vitro. PhF was collected from an ear of human Fas ligand transgenic porcine and cell-line was established by MGEM Inc. PhF labeled with CFSE co-cultured with human peripheral blood mononuclear cells (hPBMCs) were examined with respect to induction of tolerance and cell death when co-cultured with Dex-DCs for 3days. PhF induced the apoptosis in hPBMCs, especially CD4(+) T cells. Dex-DCs showed significant (P<0.05) reduction on the expression of CD80, CD86 and MHC class I/II, and the secretion of IL-12p70, TNF-α and IL-10, but increase of latency-associated peptide (LAP). Survival of PhF was significantly higher than that of WT and it was increased in the presence of Dex-DCs when compared to the other DCs (i.e.,DCs, LPS-treated DCs and LPS/Dex-treated DCs) in vitro. Survival of PhF did not change by co-culture with Dex-DCs due to apoptotic cell death of Dex-DCs. Dex-DCs reduced the death of porcine fibroblasts and, at the same time, PhF induced the apoptosis from hPBMCs, but it was not synergistic.

Update: biomarkers for idiopathic inflammatory myopathies

PURPOSE OF REVIEW

Establishing diagnoses and distinguishing active disease from chronic injury remain significant clinical challenges in idiopathic inflammatory myopathies (IIM). Recent 'discovery' approaches utilizing novel genomic and proteomic techniques have revealed candidate molecular biomarkers to augment clinical and classical histological data.

RECENT FINDINGS

Whole blood and serum Type 1 interferons (IFN-1) and IFN-1 inducible genes are gaining traction as disease biomarkers in IIM. IFNβ is emerging as a disease activity marker specifically for dermatomyositis. Recently, molecules associated with innate immune-cell function, including TLR-3, high mobility group box (HMGB)-1, B7 Homolog 1, S100A4, and resistin have been detected in tissues of dermatomyositis patients. Serum Interleukin-17 (IL-17) and IL-23 correlate with active disease in early IIM. Antibodies recognizing the Survival Motor Neuron complex have been newly identified in a subset of patients with polymyositis. Protein aggregates are potential disease activity sensors for inclusion body myositis. Skin and lung harbor potential biomarkers for IIM.

SUMMARY

Recent advances in understanding the pathogenesis of IIM have led to discovery of molecules that are candidate biomarkers of disease activity. Type 1 interferon and myeloid-cell signatures are leading candidate markers for use in IIM activity monitoring.

Novel biomarker combination improves the diagnosis of serious bacterial infections in Malawian children

Background

High throughput technologies offer insight into disease processes and heightens opportunities for improved diagnostics. Using transcriptomic analyses, we aimed to discover and to evaluate the clinical validity of a combination of reliable and functionally important biomarkers of serious bacterial infection (SBI).

Methods

We identified three previously reported biomarkers of infection (neutrophil gelatinase-associated lipocalin (NGAL), granulysin and resistin) and measured gene expression using quantitative real-time PCR. Protein products related to the three transcripts were measured by immunoassays.

Results

Relative gene expression values of NGAL and resistin were significantly increased, and expression of granulysin significantly decreased in cases compared to controls. Plasma concentrations of NGAL and resistin were significantly increased in children with confirmed SBI compared to children with no detectable bacterial infection (NBI), and to controls (287 versus 128 versus 62 ng/ml and 195 versus 90 versus 18 ng/ml, respectively, p < 0.05). Plasma protein concentrations of NGAL and resistin were significantly increased in non-survivors compared to survivors (306 versus 211 and 214 versus 150 ng/ml, p = 0.02). The respective areas under the curve (AUC) for NGAL, resistin and procalcitonin in predicting SBI were 0.79, 0.80 and 0.86, whilst a combination of NGAL, resistin and procalcitonin achieved an AUC of 0.90.

Conclusions

We have demonstrated a unique combination of diagnostic biomarkers of SBI using transcriptomics, and demonstrated translational concordance with the corresponding protein. The addition of NGAL and resistin protein measurement to procalcitonin significantly improved the diagnosis of SBI.

Lactobacillus plantarum lipoteichoic acid alleviates TNF-α-induced inflammation in the HT-29 intestinal epithelial cell line

We recently observed that lipoteichoic acid (LTA) isolated from Lactobacillus plantarum inhibited endotoxin-mediated inflammation of the immune cells and septic shock in a mouse model. Here, we examined the inhibitory role of L. plantarum LTA (pLTA) on the inflammatory responses of intestinal epithelial cells (IEC). The human colon cell line, HT-29, increased interleukin (IL)-8 expression in response to recombinant human tumor necrosis factor (TNF)-alpha, but not in response to bacterial ligands and interferon (IFN)-gamma. TNF-α also increased the production of inducible nitric oxide synthase (iNOS), nitric oxide (NO), and intercellular adhesion molecule 1 (ICAM-1) through activation of p38 mitogen-activated protein kinase (MAPK) from HT-29 cells. However, the inflammatory response of HT-29 on TNF-α stimulation was significantly inhibited by pLTA treatment. This pLTA-mediated inhibition accompanied the inhibition of nuclear factor (NF)-kappa B and MAPKs. Our data suggest that pLTA regulates cytokine-mediated immune responses and may be a good candidate for maintaining intestinal homeostasis against excessive inflammation.

Resistin is associated with breach of tolerance and anti-nuclear antibodies in patients with hepatobiliary inflammation

Resistin is a cysteine-rich protein, which is abundantly expressed at the site of inflammation, and acts as a regulator of the NF-kB-dependent cytokine cascade. The aim of this study was to evaluate resistin levels in relation to inflammatory mediators, disease phenotype and autoantibody status in a spectrum of pathological conditions of the gastrointestinal tract. Resistin levels were measured with an ELISA in sera originated from 227 patients and 40 healthy controls (HC). Fifty patients diagnosed with non-alcoholic fatty liver disease (NAFLD), 53 ulcerative colitis (UC), 51 Crohn's disease (CD), 46 autoimmune hepatitis (AIH) and 27 primary sclerosing cholangitis (PSC) were included. The sera were analysed with respect to biochemical parameters of systemic inflammation and liver function and to the presence of antibodies to nuclear antigens (ANA), mitochondria (AMA) and smooth muscle (SMA). Compared with HC, resistin levels were raised in AIH (P = 0.017) and PSC (P = 0.03); compared with NAFLD, levels were elevated in CD (P = 0.041), AIH (P < 0.001) and PSC (P < 0.001). Patients with elevated levels of resistin were more often treated with corticosteroids, but no difference was found between active disease and clinical remission. Resistin levels were significantly higher in ANA-positive individuals compared with ANA-negative (P = 0.025). Resistin levels were directly correlated with IL-6 (r = 0.30, P = 0.02) and IL-8 (r = 0.51, P < 0.001). Elevated levels of resistin were prominent in patients with hepatobiliary inflammation and were associated with breach of self-tolerance, i.e. ANA positivity. Thus, we propose that resistin may be an important marker of disease severity in autoantibody-mediated gastrointestinal inflammatory diseases.

Intracellular survival of Staphylococcus aureus in adipocyte-like differentiated 3T3-L1 cells is glucose dependent and alters cytokine, chemokine, and adipokine secretion

Although obesity and type 2 diabetes mellitus are associated with Gram-positive infections and a worse clinical outcome, it is unknown whether adipocytes can be infected by Gram-positive bacteria. Adipocyte-like differentiated 3T3-L1 cells and Staphylococcus aureus were used for infection experiments under normoglycemic (100 mg/dl) and hyperglycemic (450 mg/dl) conditions in the presence/absence of insulin (1 μm). Intracellular presence and survival of S. aureus was investigated quantitatively. Supernatant cytokines, chemokines, and adipokines were measured by ELISA. Lipid metabolism and cellular morphology of infected adipocytes were investigated by different techniques. The present study provides the proof of principle that adipocyte-like cells can be infected by S. aureus dose dependently for up to 5 d. Importantly, low bacterial inocula did not affect cell viability. Intracellular survival of S. aureus was glucose dependent but not insulin dependent, and insulin receptor expression and insulin receptor signaling were not altered. Infection increased macrophage chemoattractant protein-1, visfatin, and IL-6 secretion, whereas resistin and adiponectin were decreased. Infected adipocytes had higher intracellular triacylglycerol concentrations and larger lipid droplets because of a decreased lipolysis. Taken together, infection of adipocytes by S. aureus is glucose dependent, inhibits cellular lipolysis, and affects the secretion of immunomodulating adipokines differentially. Because cell viability is not affected during infection, adipose tissue might function as a host for chronic infection by bacteria-causing metabolic, proinflammatory, and prodiabetic disturbances.

Intranasal immunization with plasmid DNA encoding spike protein of SARS-coronavirus/polyethylenimine nanoparticles elicits antigen-specific humoral and cellular immune responses

Background

Immunization with the spike protein (S) of severe acute respiratory syndrome (SARS)-coronavirus (CoV) in mice is known to produce neutralizing antibodies and to prevent the infection caused by SARS-CoV. Polyethylenimine 25K (PEI) is a cationic polymer which effectively delivers the plasmid DNA.

Results

In the present study, the immune responses of BALB/c mice immunized via intranasal (i.n.) route with SARS DNA vaccine (pci-S) in a PEI/pci-S complex form have been examined. The size of the PEI/pci-S nanoparticles appeared to be around 194.7 ± 99.3 nm, and the expression of the S mRNA and protein was confirmed in vitro. The mice immunized with i.n. PEI/pci-S nanoparticles produced significantly (P < 0.05) higher S-specific IgG1 in the sera and mucosal secretory IgA in the lung wash than those in mice treated with pci-S alone. Compared to those in mice challenged with pci-S alone, the number of B220⁺ cells found in PEI/pci-S vaccinated mice was elevated. Co-stimulatory molecules (CD80 and CD86) and class II major histocompatibility complex molecules (I-A^d) were increased on CD11c⁺ dendritic cells in cervical lymph node from the mice after PEI/pci-S vaccination. The percentage of IFN-γ-, TNF-α- and IL-2-producing cells were higher in PEI/pci-S vaccinated mice than in control mice.

Conclusion

These results showed that intranasal immunization with PEI/pci-S nanoparticles induce antigen specific humoral and cellular immune responses.

Resistin enhances the expansion of regulatory T cells through modulation of dendritic cells

Background

Resistin, a member of adipokine family, is known to be involved in the modulation of immune responses including inflammatory activity. Interestingly, resistin is secreted by adipocytes in mice and rats whereas it is secreted by leukocytes in humans. However, the mechanism behind the effect of resistin on the expansion of regulatory T cells (Tregs) remains poorly understood. Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs.

Results

Both protein and mRNA expression of FoxP3, a representative marker of Tregs, increased in a dose-dependent manner when peripheral blood mononuclear cells were treated with resistin. At the same time, resistin had no direct effect on the induction of FoxP3 in CD4⁺ T cells, suggesting an indirect role through other cells type(s). Since DCs are an important player in the differentiation of T cells, we focused on the role of DCs in the modulation of Tregs by resistin. Resistin suppressed the expression of interferon regulatory factor (IRF)-1 and its target cytokines, IL-6, IL-23p19 and IL-12p40, in DCs. Furthermore, FoxP3 expression is increased in CD4⁺ T cells when co-cultured with DCs and concomitantly treated with resistin.

Conclusion

Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

Ginsenoside Re enhances survival of human CD4+ T cells through regulation of autophagy

In the present study, we examined the effects of ginsenoside Re (Re) on cytokine expression, cytokine-dependent autophagy and cell survival in human CD4(+) T cells. When CD4(+) T cells isolated from human peripheral blood were treated with Re, LC3 and monodansylcadaverine (MDC), representative markers of autophagy, were decreased in a dose-dependent manner. Interestingly, Re suppressed the production of interferon-gamma (IFN-gamma) and immunity-related GTPase family M (IRGM) in CD4(+) T cells whereas no changes in other autophagy-related signaling molecules (ERK, p38 and AKT-mTOR-p70S6k) were found. Concomitantly, we observed that Re increased the proliferation of CD4(+) T cells with decreased cell death. Our results demonstrate that ginsenoside Re enhanced viability of CD4(+) T cells through the regulation of IFN-gamma-dependent autophagy activity.

Neutrophil-derived hyperresistinemia in severe acute streptococcal infections

The concept of neutrophil activation and degranulation as important contributors to disease pathology in invasive group A streptococcal infections has recently been emphasized. This study focuses on two of the most severe streptococcal manifestations, toxic shock syndrome and necrotizing fasciitis, and the newly described proinflammatory molecule resistin, known to derive from adipocytes and monocytes. We demonstrate for the first time that these conditions are characterized by hyperresistinemia in circulation as well as at the local site of infection. Importantly, analyses of patient tissue biopsies and whole blood revealed that neutrophils represent a novel and dominant source of resistin in bacterial septic shock. This was confirmed by the identification of resistin within neutrophil azurophilic granules. In vitro assays using primary neutrophils showed that resistin release was readily triggered by streptococcal cell wall components and by the streptococcal M1 protein, but not by the potent streptococcal superantigens. This is the first report demonstrating that resistin is released from neutrophils in response to microbial stimuli, which adds resistin to the neutrophil granule proteins that are likely to contribute to the pathologic inflammatory responses associated with severe streptococcal infections.