Increased activity of interleukin-23/interleukin-17 proinflammatory axis in obese women

Assessment of blood biomarkers in adolescents classified by body mass index and body fat percentage

The study aimed to compare biomarkers in groups of adolescents classified simultaneously according to body mass index (BMI) and body fat percentage measured by air displacement plethysmography. This was a cross-sectional study with 533 adolescents 18 to 19 years of age in São Luís, Maranhão, Brazil. BMI was classified as adequate (< 25kg/m2) versus excess weight (≥ 25kg/m2). High body fat percentage was defined as ≥ 25% for males and ≥ 30% for females. The adolescents were classified in four groups: "normal weight" (adequate BMI and body fat percentage), "normal weight obese" (adequate BMI with high body fat percentage), "excess weight with adequate body fat percentage", and "excess weight with high body fat percentage". Girls showed higher proportions of "normal weight obesity" (15.6%) and "excess weight with high body fat percentage" (17.1%). "Normal weight obese" adolescents exhibited higher mean values for total cholesterol (172.5mg/dL) and LDL-cholesterol (103.5mg/dL). Those with "excess weight and high body fat percentage" showed lower mean HDL-cholesterol (43.2mg/dL) compared to the other groups, higher mean interleukin-6 (2.7pg/mL) than "normal weight" and "excess weight and adequate body fat percentage" adolescents, and higher median triglycerides (114.0mg/dL) and C-reactive protein (0.14ng/mL) than "normal weight" and "normal weight obese" adolescents. Those with "excess weight and adequate body fat percentage" exhibited the same C-reactive protein levels as those with "excess weight and high body fat percentage". Assessment of nutritional status by BMI alone is limited, since 6.8% of the adolescents presented high body fat percentage despite normal BMI, and those who were "normal weight obese" had two biomarkers that were worse than for adolescents with "excess weight and high body fat percentage".

IL-17A in the Psoriatic Patients' Serum and Plaque Scales as Potential Marker of the Diseases Severity and Obesity

The aim of the study was to evaluate concentrations of IL-17 in the serum and plaque scales of psoriatic patients. We analyzed their association with the clinical activity of the disease and with body mass index (BMI). Demographic data, medical history, serum, and scale from psoriatic plaques for assessment of IL-17 were collected from all the participants. The disease severity was assessed with PASI (Psoriasis Area and Severity Index), BSA (Body Surface Area), PGA (Physician Global Assessment), NAPSI (Nail Psoriasis Severity Index), and DLQI (Dermatology Quality of Life Index) scores. Obesity was diagnosed by calculating body mass index. Serum and scale concentration of IL-17 was determined with Human IL-17A High Sensitivity ELISA kit and Human IL-17 ELISA kit. In the psoriatic patients, BMI was statistically significantly higher than in the control group. Most of the patients presented BMI higher than normal. Our study confirms that overweight is a problem among psoriatic patients. A significant positive correlation between the IL-17 serum and scale concentrations and psoriasis severity indicates that IL-17 can be used as the marker of disease severity. More data from human studies can be crucial for understanding that relationship between IL-17, psoriasis, and obesity.

Sleeve Gastrectomy and Roux-en-Y Gastric Bypass Attenuate Pro-inflammatory Small Intestinal Cytokine Signatures

BACKGROUND

Bariatric surgery rapidly induces improvements in type 2 diabetes (T2D) in concert with reduction in systemic markers of inflammation. The impact of bariatric surgery on local intestinal immunity is not known. We hypothesize that sleeve gastrectomy (SG) and gastric bypass (RYGB) surgeries resolve obesity-induced intestinal inflammation, thereby promoting T2D resolution.

METHODS

SG and RYGB, or control surgery was performed in SD rats (n = 4-6/group). Key cytokines involved in insulin resistance (TNF-α, IFN-γ), inflammasome activation (IL-1β, IL-18), inflammation resolution (IL-10, IL-33), and Th17 cell responses (IL-17, IL-23) were measured by qPCR in mucosal scrapings of jejunum at 4 weeks post-surgery. Intestinal cytokine expressions were correlated with weight change, systemic and portal glucose, and insulin levels in response to an enteral glucose load.

RESULTS

SG downregulated IL-17 and IL-23 in both proximal and distal jejunum, and IFN-γ was reduced only in distal jejunum (p < 0.05). Jejunal IL-17 and IL-23 expression correlated positively with weight changes after SG (0.93 and 0.98, respectively; p < 0.05). Changes in IFN-γ correlated strongly with insulin levels in portal and systemic circulation (0.99 and 0.95, respectively, p < 0.05). As with SG, IFN-γ, IL-17, and IL-23 were significantly reduced by RYGB. RYGB also reduced TNF-α and IL-18 and increased IL-33 levels (p < 0.05).

CONCLUSIONS

RYGB and SG reduce expression of pro-inflammatory cytokines IL-17, IL-23, and IFN-γ in the jejunum. RYGB showed attenuation of additional pro-inflammatory cytokines and enhanced expression of IL-33. Post-surgical changes in intestinal IL-17, IL-23, and IFN-γ correlate strongly with changes in weight and glucose-triggered insulin responses.

The role of the interleukin-23/Th17 pathway in cardiometabolic comorbidity associated with psoriasis

Alterations in the innate and adaptive immunity underpin psoriasis pathophysiology, with the Th17 cells subset now recognized as the fundamental cells in the key controlling pathway involved in its pathogenesis. Since psoriasis is a systemic disease with important comorbidity, further knowledge on the interleukin (IL)‐23/Th17 axis led to the hypothesis that there may be shared pathogenic pathways between primary skin disease and comorbidity. Psoriasis has been identified as a risk factor for cardiovascular and metabolic disease, and increasing evidence gives support to this epidemiological observation from the clinical‐pathologically field. As an example, increased levels of IL‐23 and IL‐23R have been found in human atherosclerotic plaque, and levels correlated with symptom duration and mortality. Also, upregulation of IL‐23/IL‐17 seems to play an important role in both myocardial damage and stroke, with interesting reports on deleterious effect neutralization after administration of related anti‐bodies in both associated conditions. In diabetic patients, increased levels of IL‐23/IL‐17 have also been observed and available data support a synergistic role of IL‐23/IL‐17 in β‐cells damage. In obesity, signs of an expansion of Th17 subset in adipose tissue have been reported, as well as elevated concentrations of IL‐23 in obese patients. In non‐alcoholic fatty liver disease, closely related to metabolic syndrome, but also in other mentioned cardiometabolic disorders, a predominance of IL‐23 and other related pro‐inflammatory factors has been identified as participating in their pathogenesis. Thus, the involvement of the IL‐23/Th17 axis in these shared psoriasis‐cardiometabolic pathogenic mechanisms is reviewed and discussed in the light of the existing preclinical and clinical evidence, including that from comorbid psoriasis patients.

Inflammation and fibrosis in chronic liver diseases including non-alcoholic fatty liver disease and hepatitis C

At present chronic liver disease (CLD), the third commonest cause of premature death in the United Kingdom is detected late, when interventions are ineffective, resulting in considerable morbidity and mortality. Injury to the liver, the largest solid organ in the body, leads to a cascade of inflammatory events. Chronic inflammation leads to the activation of hepatic stellate cells that undergo trans-differentiation to become myofibroblasts, the main extra-cellular matrix producing cells in the liver; over time increased extra-cellular matrix production results in the formation of liver fibrosis. Although fibrogenesis may be viewed as having evolved as a “wound healing” process that preserves tissue integrity, sustained chronic fibrosis can become pathogenic culminating in CLD, cirrhosis and its associated complications. As the reference standard for detecting liver fibrosis, liver biopsy, is invasive and has an associated morbidity, the diagnostic assessment of CLD by non-invasive testing is attractive. Accordingly, in this review the mechanisms by which liver inflammation and fibrosis develop in chronic liver diseases are explored to identify appropriate and meaningful diagnostic targets for clinical practice. Due to differing disease prevalence and treatment efficacy, disease specific diagnostic targets are required to optimally manage individual CLDs such as non-alcoholic fatty liver disease and chronic hepatitis C infection. To facilitate this, a review of the pathogenesis of both conditions is also conducted. Finally, the evidence for hepatic fibrosis regression and the mechanisms by which this occurs are discussed, including the current use of antifibrotic therapy.

From Influenza Virus to Novel Corona Virus (SARS-CoV-2)-The Contribution of Obesity

From the beginning of 2020, the governments and the health systems around the world are tackling infections and fatalities caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) resulting in the coronavirus disease 2019 (COVID-19). This virus pandemic has turned more complicated as individuals with co-morbidities like diabetes, cardiovascular conditions and obesity are at a high risk of acquiring infection and suffering from a more severe course of disease. Prolonged viral infection and obesity are independently known to lower the immune response and a combination can thus result in a "cytokine storm" and a substantial weakening of the immune system. With the rise in obesity cases globally, the chances that obese individuals will acquire infection and need hospitalization are heightened. In this review, we discuss why obesity, a low-grade chronic inflammation, contributes toward the increased severity in COVID-19 patients. We suggest that increased inflammation, activation of renin-angiotensin-aldosterone system, elevated adipokines and higher ectopic fat may be the factors contributing to the disease severity, in particular deteriorating the cardiovascular and lung function, in obese individuals. We look at the many lessons learnt from the 2009 H1N1 influenza A pandemic and relate it to the very little but fast incoming information that is available from the SARS-CoV-2 infected individuals with overweight and obesity.

The Immune Landscape of Visceral Adipose Tissue During Obesity and Aging

Obesity and aging represent major health burdens to the global adult population. Both conditions promote the development of associated metabolic diseases such as insulin resistance. The visceral adipose tissue (VAT) is a site that becomes dysfunctional during obesity and aging, and plays a significant role during their pathophysiology. The changes in obese and aging VAT are now recognized to be partly driven by a chronic local inflammatory state, characterized by immune cells that typically adopt an inflammatory phenotype during metabolic disease. Here, we summarize the current knowledge on the immune cell landscape of the VAT during lean, obese, and aged conditions, highlighting their similarities and differences. We also briefly discuss possible linked mechanisms that fuel obesity- and age-associated VAT dysfunction.

Th17 and Treg Balance in Children With Obesity and Metabolically Altered Status

Background: Chronic low-grade inflammation and activation of the immune system are hallmark pathogenic mechanisms involved in metabolic dysfunction and are related to obesity. In particular, the involvement of regulatory and pro-inflammatory lymphocyte subpopulations has been reported in adults. We evaluated the Th17/Treg lymphocyte balance in obese and normal weight children, in relation with their metabolic status. Methods: We enrolled 50 pediatric patients. According to metabolic status, subjects were classified into: metabolically healthy (MH) and metabolically unhealthy (MU) groups. MU phenotype was defined as the presence of at least one of the following risk factors: blood pressure >90th percentile, glycemia>100 mg/dl, HDL cholesterol <40 mg/dl, triglycerides>100 mg/dl (<10 years) or >130 mg/dl (>10 years), impaired insulin sensitivity with HOMA-IR>97.5th percentile. Patient Treg and Th17 profiles were also evaluated. Results: Based on the presence of metabolic and/or cardiovascular pathological parameters, we classified 15 MU (30%) and 35 MH (70%) children; all MU children were obese. Analyzing the correlations between lymphocyte subpopulations and metabolic data, we noted a correlation between Th17 percentage and systolic hypertension (p = 0.01, r = -0.37); Treg/Th17 ratio and HOMA-IR (p = 0.02, r = 0.32) and systolic hypertension (p = 0.05, r = 0.30). Conclusion: Children with obesity have a high risk of developing metabolic and cardiovascular complications. The Th17/Treg lymphocyte balance appears to be involved in glycemic homeostasis and blood pressure control. Careful and early monitoring of the immune system would facilitate new early preventive strategies in pediatric metabolic diseases.

Decreased methylation profiles in the TNFA gene promoters in type 1 macrophages and in the IL17A and RORC gene promoters in Th17 lymphocytes have a causal association with non-atopic asthma caused by obesity: A hypothesis

Obesity is a serious public health problem worldwide and has been associated in epidemiological studies with a unique type of non-atopic asthma, although the causal association of asthma and obesity has certain criteria, such as the strength of association, consistency, specificity, temporality, biological gradient, coherence, analogy and experimentation; nevertheless, the biological plausibility of this association remains uncertain. Various mechanisms have been postulated, such as immunological, hormonal, mechanical, environmental, genetic and epigenetic mechanisms. Our hypothesis favours immunological mechanisms because some cytokines, such as tumour necrosis factor alpha (TNF-α) and interleukin (IL)-17A, are responsible for orchestrating low-grade systemic inflammation associated with obesity; however, these cytokines are regulated by epigenetic mechanisms, such as gene promoter methylation.

IL-17A promotes fatty acid uptake through the IL-17A/IL-17RA/p-STAT3/FABP4 axis to fuel ovarian cancer growth in an adipocyte-rich microenvironment

Pro-inflammatory cytokines are crucial mediators of cancer development, representing potential targets for cancer therapy. The molecular mechanism of a vital pro-inflammatory cytokine, IL-17A, in cancer progression and its potential use in therapy through influencing fatty acid (FA) metabolism, especially FA uptake of cancer cells, remains unknown. In the present study, we used IL-17A and ovarian cancer (OvCa), a representative of both obesity-related and inflammation-related cancers, to explore the interactions among IL-17A, cancer cells and adipocytes (which can provide FAs). We found that in the presence of palmitic acid (PA), IL-17A could directly increase the cellular uptake of PA, leading to the proliferation of OvCa cells via the IL-17A/IL-17RA/p-STAT3/FABP4 axis rather than via CD36. Moreover, in vivo experiments using an orthotopic implantation model in IL-17A-deficient mice demonstrated that endogenous IL-17A could fuel OvCa growth and metastasis with increased expression of FABP4 and p-STAT3. Furthermore, analysis of clinical specimens supported the above findings. Our data not only provide useful insights into the clinical intervention of the growth and metastasis of the tumors (such as OvCa) that are prone to growth and metastasis in an adipocyte-rich microenvironment (ARM) but also provides new insights into the roles of IL-17A in tumor progression and immunomodulatory therapy of OvCa.

Effect of High-Fat Diets on Oxidative Stress, Cellular Inflammatory Response and Cognitive Function

Cognitive dysfunction is linked to chronic low-grade inflammatory stress that contributes to cell-mediated immunity in creating an oxidative environment. Food is a vitally important energy source; it affects brain function and provides direct energy. Several studies have indicated that high-fat consumption causes overproduction of circulating free fatty acids and systemic inflammation. Immune cells, free fatty acids, and circulating cytokines reach the hypothalamus and initiate local inflammation through processes such as microglial proliferation. Therefore, the role of high-fat diet (HFD) in promoting oxidative stress and neurodegeneration is worthy of further discussion. Of particular interest in this article, we highlight the associations and molecular mechanisms of HFD in the modulation of inflammation and cognitive deficits. Taken together, a better understanding of the role of oxidative stress in cognitive impairment following HFD consumption would provide a useful approach for the prevention of cognitive dysfunction.

IL-17A contributes to propagation of inflammation but does not impair adipogenesis and/or insulin response, in adipose tissue of obese individuals

BACKGROUND

Adipose tissue is infiltrated with various immune cells, including Th17 lymphocytes and monocytes/macrophages, in obese individuals. We have previously demonstrated the role of obese adipose-derived stem cells (ob-ASC) and adipocytes (AD) in the mediation of inflammation through promotion of Th17 cells and activation of monocytes. Such an inflammation resulted in impaired ob-ASC adipogenesis and AD insulin response. In the present study, we investigated the role of IL-17A in the impairment of these functions.

METHODS

With this aim, we used Secukinumab, a potent human anti-IL17A monoclonal antibody which has been approved for the treatment of some IL-17A related inflammatory diseases, notably Psoriasis. This antibody was added or not to phytohemagglutinin A-activated co-cultures of ob-ASC and mononuclear cells. The conditioning media of those co-cultures were harvested and added to AD ongoing differentiation from ob-ASC. Adipogenesis, insulin sensitivity and secretion of inflammatory cytokines were then measured using qRT-PCR, Western blots and ELISAs, respectively.

RESULTS

Surprisingly, we did not observe any direct effect of IL-17A on ob-ASC adipogenesis, despite sensitivity of ob-ASC to IL-17A. Moreover, IL-17A blockade, with the help of Secukinumab, did not lead to the recovery of adipogenesis and insulin response, when these functions were impaired by the presence of an inflammatory conditioning medium. However, the up-regulation of IL6 and IL1B mRNA expression by AD submitted to inflammatory conditioning medium was inhibited in the presence of Secukinumab, which indicates that IL-17A may play a role in the propagation of inflammation towards AD.

IN CONCLUSION

we show herein that IL-17A does not play a major role in the impairment of adipogenesis and/or insulin resistance mediated by an inflammatory environment, but contributes to the propagation of inflammation in human obese adipose tissues. This suggests a beneficial effect of anti-IL17A mAb in inflammatory pathologies, where obesity contributes to poorer response to biologic treatments.

Supplementation with Sodium Butyrate Modulates the Composition of the Gut Microbiota and Ameliorates High-Fat Diet-Induced Obesity in Mice

BACKGROUND

Short-chain fatty acids (SCFAs) have been reported to ameliorate obesity. However, the underlying mechanisms require further investigation.

OBJECTIVE

The aim of this study was to determine the role of butyrate, an SCFA, in the regulation of obesity, low-grade chronic inflammation, and alterations of microbiota composition in mice.

METHODS

Male C57BL/6J mice, 4-5 wk of age, were divided into 3 groups (n = 8 mice/group): low-fat diet (LFD; 10% energy from fat), high-fat diet (HFD; 45% energy from fat), or high-fat diet plus sodium butyrate (HSB). HSB mice received sodium butyrate at a concentration of 0.1 M in drinking water for 12 wk. Measures of inflammation, obesity, and intestinal integrity were assessed. Serum lipopolysaccharide (LPS) concentrations were measured in the 3 groups. Fecal samples were collected for gut microbiota analysis.

RESULTS

In HFD mice, body weight gain and hepatic triglyceride (TG), serum interleukin-6 (IL-6), and serum tumor necrosis factor (TNF)-α levels were 1-4 times higher than those in LFD mice (P < 0.05); they were 34-42% lower in HSB mice compared with HFD mice (P < 0.05). The HFD group had 28%-48% lower mRNA expression of both Tjp1 and Ocln in the ileum and colon compared with levels in LFD or HSB mice (P < 0.05), whereas there was no difference in expression levels between LFD and HSB mice. Furthermore, in HSB mice, serum LPS concentration was 53% lower compared with that in HFD mice but still 23% higher than that in LFD mice (P < 0.05). Results from principal component analysis showed that HSB and LFD mice had a similar gut microbiota structure, which was significantly different from that in HFD mice (P < 0.05).

CONCLUSIONS

Sodium butyrate administration beneficially changed HFD-induced gut microbiota composition and improved intestinal barrier, leading to lower serum LPS concentrations. These changes may correspond with improvements in obesity-related lipid accumulation and low-grade chronic inflammation.

Omega-3 Polyunsaturated Fatty Acids Inhibit IL-17A Secretion through Decreased ICAM-1 Expression in T Cells Co-Cultured with Adipose-Derived Stem Cells Harvested from Adipose Tissues of Obese Subjects

SCOPE

Obese adipose tissue (AT) is infiltrated by inflammatory immune cells including IL-17A-producing-T (Th17) cells. It has been previously demonstrated that adipose-derived stem cells from obese (ob-ASCs), but not lean AT promote Th17 cells. Because n-3 PUFAs are known to inhibit obese AT inflammation, it is tested here whether they could inhibit ob-ASC-mediated IL-17A secretion.

METHODS AND RESULTS

The n-3 PUFA precursor, alpha-linolenic acid (ALA), or its derivatives, eicosapentaenoic, or docosahexaenoic acid, is added to co-cultures of human ob-ASCs and mononuclear cells (MNCs). All three inhibited IL-17A, but not IL-1β, IL-6, nor TNFα  secretion. As a control, palmitic acid (PA), a saturated fatty acid, did not inhibit IL-17A secretion. ALA also inhibited IL-17A secretion mediated by adipocytes differentiated from ob-ASCs. Toll-like-receptor 4 is shown to be involved in ob-ASC-mediated-IL-17A secretion, and to be inhibited by ALA, together with Cyclo-Oxygenase-2 and Signal-Transducer-and-Activator-of-transcription-3. In addition, ALA down-regulated Intercellular-Adhesion-Molecule-1 (ICAM-1) expression in both monocytes and ASCs, which resulted in decreased interactions between ob-ASCs and MNCs, and inhibition of IL-17A secretion.

CONCLUSION

It is demonstrated herein that ALA inhibits Th17 cell promotion, through decreased ICAM-1expression in both ob-ASCs and monocytes. This novel mechanism may contribute to explain the beneficial effects of n-3 PUFA in IL-17A-related inflammatory pathologies.

The Differential Roles of T Cells in Non-alcoholic Fatty Liver Disease and Obesity

Non-alcoholic fatty liver disease (NAFLD) constitutes a spectrum of disease states characterized by hepatic steatosis and is closely associated to obesity and the metabolic syndrome. In non-alcoholic steatohepatitis (NASH), additionally, inflammatory changes and hepatocellular damage are present, representing a more severe condition, for which the treatment is an unmet medical need. Pathophysiologically, the immune system is one of the main drivers of NAFLD progression and other obesity-related comorbidities, and both the innate and adaptive immune system are involved. T cells form the cellular component of the adaptive immune system and consist of multiple differentially active subsets, i.e., T helper (Th) cells, regulatory T (Treg) cells, and cytotoxic T (Tc) cells, as well as several innate T-cell subsets. This review focuses on the role of these T-cell subsets in the pathogenesis of NAFLD, as well as the association with obesity and type 2 diabetes mellitus, reviewing the available evidence from both animal and human studies. Briefly, Th1, Th2, Th17, and Th22 cells seem to have an attenuating effect on adiposity. Th2, Th22, and Treg cells seem to decrease insulin resistance, whereas Th1, Th17, and Tc cells have an aggravating effect. Concerning NAFLD, both Th22 and Treg cells appear to have an overall tempering effect, whereas Th17 and Tc cells seem to induce more liver damage and fibrosis progression. The evidence regarding the role of the innate T-cell subsets is more controversial and warrants further exploration.

High-Fat Meal–Induced Changes in Markers of Inflammation and Angiogenesis in Healthy Adults Who Differ by Age and Physical Activity Level

Background

Inflammation and angiogenesis are key facets of cardiovascular disease pathophysiology. Age and physical activity level can influence fasting systemic inflammation, but the impact of these factors on postprandial inflammation is unknown. In addition, markers of angiogenesis have never been tested in the context of a single high-fat meal (HFM).

Objective

The purpose of this study was to investigate the effects of an HFM on markers of inflammation and angiogenesis in individuals of different ages and physical activity levels.

Methods

Twenty-two healthy adults—8 younger active (YA) adults (4 men, 4 women; mean ± SD age: 25 ± 5 y), 8 older active (OA) adults (4 men, 4 women; 67 ± 5 y), and 6 older inactive (OI) adults (3 men, 3 women; 68 ± 7 y)—consumed an HFM [63% fat (39% saturated fat, 14% monounsaturated fat, 10% polyunsaturated fat), 34% carbohydrate; 12 kcal/kg body mass; 927 ± 154 kcal]. Fourteen inflammatory and 9 angiogenic markers were measured at baseline and 3 and 6 h postmeal.

Results

Significant group effects were observed in interleukin (IL)-10 (YA > OA; P = 0.02), IL-23 (YA > OA; P = 0.02), tumor necrosis factor (TNF)-α (OA < OI; P = 0.04), and vascular endothelial growth factor (VEGF)-C (YA < OA; P = 0.001). IL-8, VEGF-A, VEGF-C, and heparin-binding epidermal growth factor–like growth factor significantly increased, whereas granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-1β, IL-5, IL-10, IL-12, IL-13, IL-17A, IL-23, TNF-α, leptin, angiopoietin-2, and follistatin significantly decreased after HFM consumption (P’s < 0.05). Notably, VEGF-A and VEGF-C were significantly higher at 3 h [mean difference: 22.5 pg/mL (VEGF-A); 73.5 pg/mL (VEGF-C)] and 6 h postmeal [mean difference: 26.9 pg/mL (VEGF-A); 81.2 pg/mL (VEGF-C)].

Conclusions

A novel finding of this study was the robust increase in VEGF after an HFM. There were also group differences in several inflammatory markers (IL-10 and IL-23 greater in YA than OA, and TNF-α lower in OA than OI) that suggest a potential influence of age and physical activity level.

Effect of the anti-IL-17 antibody on allergic inflammation in an obesity-related asthma model

BACKGROUND/AIMS

The co-occurrence of obesity aggravates asthma symptoms. Diet-induced obesity increases helper T cell (TH) 17 cell differentiation in adipose tissue and the spleen. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pravastatin can potentially be used to treat asthma in obese patients by inhibiting interleukin 17 (IL-17) expression. This study investigated the combined effects of pravastatin and anti-IL-17 antibody treatment on allergic inflammation in a mouse model of obesity-related asthma.

METHODS

High-fat diet (HFD)-induced obesity was induced in C57BL/6 mice with or without ovalbumin (OVA) sensitization and challenge. Mice were administered the anti-IL-17 antibody, pravastatin, or both, and pathophysiological and immunological responses were analyzed.

RESULTS

HFD exacerbated allergic airway inflammation in the bronchoalveolar lavage fluid of HFD-OVA mice as compared to OVA mice. Blockading of the IL-17 in the HFD-OVA mice decreased airway hyper-responsiveness (AHR) and airway inflammation compared to the HFD-OVA mice. Moreover, the administration of the anti-IL-17 antibody decreased the leptin/adiponectin ratio in the HFD-OVA but not the OVA mice. Co-administration of pravastatin and anti-IL-17 inhibited airway inflammation and AHR, decreased goblet cell numbers, and increased adipokine levels in obese asthmatic mice.

CONCLUSION

These results suggest that the IL-17-leptin/adiponectin axis plays a key role in airway inflammation in obesity-related asthma. Our findings suggest a potential new treatment for IL-17 as a target that may benefit obesity-related asthma patients who respond poorly to typical asthma medications.

T Cells in Adipose Tissue: Critical Players in Immunometabolism

Adipose tissue performs immunoregulatory functions in addition to fat storage. Various T cells in different fat depots either help maintain metabolic homeostasis under healthy conditions or contribute to metabolic disorders in pathological conditions such as obesity, diabetes, cardiovascular diseases, or even cancer. These T cells play critical roles in immunometabolism, which refers to the intersection of immunity and metabolism. Numerous studies have examined the presence and changes of different T cell subsets, including helper T cells, regulatory T cells, cytotoxic T cells, and natural killer T cells, in adipose depots in health and diseases. In this review, we will discuss the adipose tissue niches that influence the patterns and functions of T cell subsets and in turn the impact of these T cells on cell- or body-based immunometabolism accounting for health and obesity.

Th17 and Treg lymphocytes in obesity and Type 2 diabetic patients

Assumption that the pathogenesis of obesity-associated type 2 diabetes (T2DM) encompasses inflammation and autoimmune aspects is increasingly recognized. In the state of obesity and T2DM, the imbalance of T helper 17 (Th17) cells and regulatory T (Treg) cells are observed. These alterations reflect a loss of T cell homeostasis, which may contribute to tissue and systemic inflammation and immunity in T2DM. In this review we will discuss the accumulating data supporting the concept that Th17/Treg mediated immune responses are present in obesity-related T2DM pathogenesis, and provide evidences that restoration of Th17/Treg imbalance may be a possible therapeutic avenue for the prevention and treatment of T2DM and its complications.

The pleiotropic role of interleukin-17 in atherosclerosis

Atherosclerosis is the main cause of cardiovascular diseases (CVDs), which considers the leading cause of mortality worldwide. Atherosclerosis is a chronic inflammatory condition of arterials' wall in which the development and the destabilization of plaque occur. Both innate and adaptive immunity play a significant role in modifying lipoproteins in arterials' wall. Recent investigations have demonstrated the opposing roles of CD4⁺ T cells subtypes in atherosclerosis. T helper-1 (Th1) response and pro-inflammatory cytokines possess proatherogenic effects, whereas T regulatory (Treg) cells have an atheroprotective role. Th17 cells have emerged as a new CD4⁺ T-cell subtype, which produce IL-17 that plays a crucial role in numerous inflammatory and autoimmune diseases. Recently, several studies have investigated the potential role of IL-17 in atherosclerosis. Some investigations have suggested a proatherogenic effect, however the others proposed an atheroprotective role. Hence, the exact role of IL-17 in the disease development and plaque stability is still debatable. In this review, we summarize the current knowledge on both atherogenesis and atheroprotective roles of IL-17. In addition, the synergistic and antagonistic effects of IL-17 with other cytokines in atherosclerosis will be discussed. On the basis of the current understanding of these roles, the possibility of developing novel therapeutic strategies against atherosclerosis may be evolved.

Microbial Insights into Asthmatic Immunopathology. A Forward-Looking Synthesis and Commentary

Asthma is an aberrant inflammatory condition of the airways affecting approximately 1 in 10 children in affluent countries. An increasing body of evidence suggests that microbial exposures during a "critical window" of development in early life play a central role in determining future asthma susceptibility. However, like the disease itself, considerable heterogeneity exists among studies in which researchers have investigated the associations between particular microbial taxa and asthma immunology. As our understanding of asthmatic pathology evolves to enable clearer definition of asthma endotypes, it will be important to consider the impact of various environmental factors on each endotype. Given the strong evidence in support of the hypothesis that early-life microbial exposures predict later disease states such as asthma, consideration of these endotypes when establishing experimental outcomes in epidemiological studies could allow for increased precision when determining exposure-outcome associations and engaging in more focused follow-up mechanistic investigations.

Systemic Inflammatory Response and Atherosclerosis: The Paradigm of Chronic Inflammatory Rheumatic Diseases

Patients with Chronic Inflammatory Rheumatic diseases (CIRD) are at increased risk of cardiovascular disease (CVD), ascribed not only to classical risk factors, but also to the presence of chronic systemic inflammatory response. Αtherosclerosis, the cornerstone of CVD, is known to be accelerated in CIRD; rheumatoid arthritis promotes atheromatosis and associates with preclinical atherosclerosis equivalent to Diabetes Mellitus, which also seems to apply for systemic lupus erythematosus. Data on ankylosing spondylitis and psoriatic arthritis, albeit more limited, also support an increased CV risk in these patients. The association between inflammation and atherosclerosis, has been thoroughly investigated in the last three decades and the role of inflammation in the pathogenesis and progression of atherogenesis has been well established. Endothelial dysfunction, oxidative stress in vascular endothelial cells and macrophage accumulation, toll-like receptor signaling, NLPR-3 formation and subsequent pro-inflammatory cytokine production, such as TNFa, IL-1β, IL-6, and TNF-like cytokine 1A, are few of the mechanisms implicated in the atherogenic process. Moreover, there is evidence that anti-inflammatory biologic drugs, such as anti-TNF and anti-IL1β agents, can decelerate the atherogenic process, thus setting new therapeutic targets for early and effective disease control and suppression of inflammation, in addition to aggressive management of classical CV risk factors.

Peripheral blood mononuclear cells of patients with latent autoimmune diabetes secrete higher levels of pro- & anti-inflammatory cytokines compared to those with type-1 diabetes mellitus following in vitro stimulation with β-cell autoantigens

Background & objectives:

Type-1 diabetes mellitus (T1DM) and latent autoimmune diabetes in adults (LADA) share similar pathological features but differ in age of onset and progression. There is a scarcity of information on differences in CD4+ T-cell responses, particularly, cytokine secretion, between the two forms of autoimmune diabetes. Here proliferative potential and concentration of pro- and anti-inflammatory cytokines secreted by peripheral blood mononuclear cells (PBMCs) of T1DM and LADA patients were compared, after in vitro stimulation with β-cell autoantigens.

Methods:

A total of 19 patients with LADA, 37 with T1DM and 20 healthy controls were compared on the basis of lymphocyte proliferation and secretion of pro- and anti-inflammatory cytokines belonging to different T-helper types after in vitro stimulation of PBMCs with insulin and glutamic acid decarboxylase 65 (GAD65).

Results:

Following insulin stimulation, LADA group secreted higher concentration of interleukin-17 (IL-17) (P=0.02) and had higher proportion of interferon gamma (IFN-γ) secretors (P<0.001) than T1DM group. Post-GAD65 stimulation, higher proportion of LADA patients secreted IL-23 than T1DM group (P=0.02). Proportion of responders, as well as levels of secreted IL-10, were significantly higher in LADA than T1DM group, following stimulation with both insulin (P=0.01) and GAD65 (P=0.03). A significant positive correlation was observed between body mass index and IL-17 levels (r=0.41, P=0.04) and fasting plasma C-peptide with IL-10 levels (r=0.37, P=0.04).

Interpretation & conclusions:

There are differences in the portfolio of cytokine secretion in diabetic subjects with varying rates of β-cell destruction as LADA subjects secrete higher levels of both pro- and anti-inflammatory cytokines on exposure to β-cell autoantigens, thus highlighting another distinguishing feature in the pathophysiology of the two forms of autoimmune diabetes.

Mast cells participate in chronic low-grade inflammation within adipose tissue

Obesity is reckoned as one of the civilization diseases, posing a considerable global health issue. Evidence points towards a contribution of multitude immune cell populations in obesity pathomechanism and the development of chronic low-grade inflammation in the expanded adipose tissue. Notably, adipose tissue is a reservoir of mast cells which number in individuals with obesity particularly increased. Some of them tend to degranulation what generate secretion of strong pro-inflammatory and regulatory mediators, as well as cytokines/chemokines. Several lines of evidence suggest that mast cells are strictly associated with pro-inflammatory status in adipose tissue by their indirect impact on immune cell attraction and activation. Furthermore, mast cells affect adipose tissue remodelling and fibrosis by adipocyte differentiation, fibroblast proliferation and enhancing extracellular matrix proteins expression. This review will summarize current knowledge on mast cell features and their role in the development of chronic low-grade inflammation within adipose tissue.

Intestinal microbiota and the immune system in metabolic diseases

The intestinal microbiota is comprised of millions of microorganisms that reside in the gastrointestinal tract and consistently interact with the host. Host factors such as diet and disease status affect the composition of the microbiota, while the microbiota itself produces metabolites that can further manipulate host physiology. Dysbiosis of the intestinal microbiota has been characterized in patients with certain metabolic diseases, some of which involve damage to the host intestinal epithelial barrier and alterations in the immune system. In this review, we will discuss the consequences of dietdependent bacterial dysbiosis in the gastrointestinal tract, and how the associated interaction with epithelial and immune cells impacts metabolic diseases.

The potential pathogenic role of IL-17/Th17 cells in both type 1 and type 2 diabetes mellitus

Diabetes mellitus (DM) is a serious medical problem affecting millions of peoples worldwide, and has a great socio-economic impacts. Cytokines possess a pivotal role in modulation of immune reactions and disease pathogenesis. T-helper type 17 (Th17) cells, an important proinflammatory CD4⁺ T cell subset secreting interleukin 17 (IL-17), has been embroiled in development of DM. There are recent evidences supporting a definitive role of Th17 cells in the etiology of type 1 diabetes (T1D). In addition, IL-17 has been shown to play a crucial role in inflammation, insulin resistance, and type 2 diabetes (T2D). Recently, small molecules which have been specified to block Th17 cells differentiation are considered as potential therapeutics for the disease. Anti-IL-17 neutralizing antibodies and/or antibodies targeting Th17 cells have been investigated to protect individuals at risk from disease development. In this review we aimed to shed light on the potential role of IL-17 and Th17 cells in both T1D and T2D pathogenesis and future therapeutic strategies.

Celastrol Alleviates Airway Hyperresponsiveness and Inhibits Th17 Responses in Obese Asthmatic Mice

Severe airway hyperresponsiveness (AHR) is a clinical feature of asthma, which has been associated with obesity and has shown a poor response to standard asthma treatments such as glucocorticoids. Numerous studies have shown that Interleukin (IL)-17 producing CD4⁺T cells (Th17 cells), which could be inhibited by celastrol, is essential in mediating steroid-resistant AHR. The following study investigates the impact of celastrol and its mechanism on the regulation of AHR in murine model of obesity and asthma. C57BL/6 mice were sensitized by intraperitoneal injection of ovalbumin (OVA) on day 1 and 13 starting from 12th week, which was followed by aerosol OVA challenge that lasted for 30 min per daily for 7 consecutive days starting from 16th week. Diet-induced obesity (DIO) mice were fed a high fat diet (HFD) for 16 weeks. Celastrol was administrated orally for 7 consecutive days, 30 min before every challenge in DIO-OVA-induced mice. Lung functions were analyzed by measuring the airway resistance (Rn) and methacholine (MCh) AHR, while H&E staining was used to examine histological changes in the lungs. Immunohistochemistry was used to observe IL-17A protein in lung tissues; flow cytometry to detect the proportion of Th17 cells in CD4⁺T cells. The concentration of cytokines IL-17A in serum was assessed by standardized sandwich ELISA, while the expression of IL-17A mRNA in lung was examined by quantitative real-time RT-PCR. Briefly, our data indicated that celastrol reduced body mass in DIO-OVA-induced obesity and asthma. Both baseline Rn and MCh AHR were significantly lower in celastrol group. Moreover, celastrol treatment decreased the frequency of Th17 cell expansion and reduced the production of IL-17A in both lung and serum. To sum up, our findings indicated that Th17 and its cytokine measured in the spleen and lung were closely associated with AHR. In addition, celastrol has shown the ability to suppress AHR through Th17 inhibition in obese asthmatic mice.

Cardiometabolic Comorbidities in Psoriasis and Psoriatic Arthritis

There is solid epidemiologic evidence linking psoriasis and psoriatic arthritis (PsA) to cardiovascular risk factors and an increased risk of developing cardiovascular disease. Chronic inflammation, with shared pathways and cytokines common to metabolic syndrome, atherosclerosis and psoriasis, might provide the basis for the cardiovascular and metabolic comorbidities of psoriasis and PsA. The purpose of this manuscript is to review recent evidence about the epidemiology and underlying mechanisms of cardiovascular risk factors and cardiovascular disease in patients with psoriasis and/or PsA; the use of analytical determinations, physiologic measures and imaging techniques as surrogate biomarkers of atherosclerosis, endothelial dysfunction and cardiovascular disease in these patients; and the epidemiological and clinical data, including results of clinical trials, supporting a cardioprotective role of anti-inflammatory and disease-modifying treatment in psoriasis and PsA.

Serum Interleukin-23 in Polish Patients with Systemic Lupus Erythematosus: Association with Lupus Nephritis, Obesity, and Peripheral Vascular Disease

Objectives

To analyze the correlation between the serum concentration of interleukin- (IL-) 23 and atherosclerotic changes, traditional atherosclerotic risk factors, the autoantibody profile, and involvement of selected organs in systemic lupus erythematosus (SLE) patients.

Patients and Methods

We studied 94 SLE patients and 27 controls. We analyzed the IL-23 serum concentration, autoantibodies, carotid intima-media thickness and atherosclerotic plaque, the ankle-brachial index, atherosclerotic risk factors, and organ manifestations.

Results

Concentrations of IL-23 significantly differed between SLE patients and the controls (p = 0.0015). On the basis of multivariate stepwise analysis, we revealed that high levels of IL-23 were associated with atherosclerotic plaque in common femoral arteries (OR = 12.67; 95% CI: 1.41-113.84), lupus nephritis (OR = 3.69; 95% CI: 1.16-12.22), and obesity (OR = 4.21; 95% CI: 1.40-12.67). Autoantibodies related to IL-23 were anti-phosphatidylethanolamine antibodies (OR = 11.06; 95% CI: 1.24-98.65) and anti-SS-B/La antibodies (OR = 15.43; 95% CI: 1.73-137.25).

Conclusions

IL-23 may be involved in lupus nephritis pathogenesis. Through its association with obesity and selected antiphospholipid antibodies, IL-23 might promote a hypercoagulable state contributing to atherothrombosis development in SLE patients.

Hyperinsulinemia enhances interleukin-17-induced inflammation to promote prostate cancer development in obese mice through inhibiting glycogen synthase kinase 3-mediated phosphorylation and degradation of interleukin-17 receptor

Interleukin-17 (IL-17) plays important roles in inflammation, autoimmune diseases, and some cancers. Obese people are in a chronic inflammatory state with increased serum levels of IL-17, insulin, and insulin-like growth factor 1 (IGF1). How these factors contribute to the chronic inflammatory status that promotes development of aggressive prostate cancer in obese men is largely unknown. We found that, in obese mice, hyperinsulinemia enhanced IL-17-induced expression of downstream proinflammatory genes with increased levels of IL-17 receptor A (IL-17RA), resulting in development of more invasive prostate cancer. Glycogen synthase kinase 3 (GSK3) constitutively bound to and phosphorylated IL-17RA at T780, leading to ubiquitination and proteasome-mediated degradation of IL-17RA, thus inhibiting IL-17-mediated inflammation. IL-17RA phosphorylation was reduced, while the IL-17RA levels were increased in the proliferative human prostate cancer cells compared to the normal cells. Insulin and IGF1 enhanced IL-17-induced inflammatory responses through suppressing GSK3, which was shown in the cultured cell lines in vitro and obese mouse models of prostate cancer in vivo. These findings reveal a mechanism underlying the intensified inflammation in obesity and obesity-associated development of aggressive prostate cancer, suggesting that targeting GSK3 may be a potential therapeutic approach to suppress IL-17-mediated inflammation in the prevention and treatment of prostate cancer, particularly in obese men.

Alterations in systemic levels of Th1, Th2, and Th17 cytokines in overweight adolescents and obese mice

BACKGROUND

Obesity represents a major problem for patients and health care systems in most industrialized countries. A chronic inflammatory state in obese individuals leads to disease conditions associated with activation of cellular immune mechanisms. Here, we sought to investigate the role of Th1-, Th2-, and Th17-related cytokines in overweight adolescents and mice on a high-fat diet.

METHODS

Plasma samples were obtained from 79 male adolescents aged 13-17 years. Thirty-seven of them had a body mass index (BMI) above the 90th age-specific percentile. Th1, Th2, and Th17 cytokines were measured using Bio-Plex multiplex technology (Bio-Rad, Hercules, USA). In an experimental approach, mice were fed with high-fat (HFD) or normal chow for 15 weeks.

RESULTS

Interleukin (IL)-17 concentrations were significantly decreased in overweight adolescents compared to lean controls [99.8 ± 7.3 pg/mL standard error of the mean (SEM) vs 146.6 ± 11.5 pg/mL SEM P = .001]. Levels of IL-17 correlated significantly with anthropometrical parameters of obesity. A concordant response was found in mice consuming a HFD for 15 weeks compared to controls (861 ± 165 pg/mL SEM vs 1575 ± 187 pg/ml SEM, P = .0183). However, a biphasic response was evident for most Th1, Th2, and Th17 cytokines as levels initially increased within the first 5 weeks on HFD and showed a decline afterwards.

CONCLUSIONS

In contrast to previous studies showing elevated levels of IL-17 in obese adults, we found a decreasing trend in overweight adolescents. This difference could possibly be related to the fact that disease conditions associated with obesity such as hypertension, vascular pathologies, diabetes, and a triggering of the Th1/Th17 axis were not yet present in overweight teenagers.

Integrated Immunomodulatory Mechanisms through which Long-Chain n-3 Polyunsaturated Fatty Acids Attenuate Obese Adipose Tissue Dysfunction

Obesity is a global health concern with rising prevalence that increases the risk of developing other chronic diseases. A causal link connecting overnutrition, the development of obesity and obesity-associated co-morbidities is visceral adipose tissue (AT) dysfunction, characterized by changes in the cellularity of various immune cell populations, altered production of inflammatory adipokines that sustain a chronic state of low-grade inflammation and, ultimately, dysregulated AT metabolic function. Therefore, dietary intervention strategies aimed to halt the progression of obese AT dysfunction through any of the aforementioned processes represent an important active area of research. In this connection, fish oil-derived dietary long-chain n-3 polyunsaturated fatty acids (PUFA) in the form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to attenuate obese AT dysfunction through multiple mechanisms, ultimately affecting AT immune cellularity and function, adipokine production, and metabolic signaling pathways, all of which will be discussed herein.

The modulatory role of cytokines IL-4 and IL-17 in the functional activity of phagocytes in diabetic pregnant women

The study investigated the role of cytokines IL-4 and IL-17 in the modulation of the functional activity of mononuclear phagocytes in diabetic pregnant women with hyperglycemia. Sixty pregnant women were assigned to the following groups: nondiabetic (ND), mild gestational hyperglycemia (MGH), gestational diabetes mellitus (GDM), or type 2 diabetes mellitus (DM2). The functional activity of phagocytes from maternal blood, cord blood, and colostrum was assessed by determining their superoxide release, phagocytosis, microbicidal activity, and intracellular Ca²⁺ release. Irrespective of glycemic status, colostrum and blood cells treated with IL-4 and IL-17 increased superoxide release in the presence of enteropathogenic Escherichia coli (EPEC). The highest phagocytosis rate was observed in cells from the DM2 group treated with IL-4. In all the groups, phagocytes from colostrum, maternal blood, and cord blood exhibited higher microbicidal activity against EPEC when treated with cytokines. IL-17 increased intracellular Ca²⁺ release by colostrum phagocytes in diabetic groups. The results indicate that the IL-4 and IL-17 modulate the functional activity of phagocytes in the maternal blood, cord blood, and colostrum of diabetic mother. The natural immunity resulting from the interaction between the cells and cytokines tested may be an alternative procedure to improve the prognosis of maternal and newborn infections.

Association of body mass index with amnestic and non-amnestic mild cognitive impairment risk in elderly

BACKGROUND

Previous studies focused on the relationship between body mass index and cognitive disorder and obtained many conflicting results. This study explored the potential effects of body mass index on the risk of mild cognitive impairment (amnestic and non-amnestic) in the elderly.

METHODS

The study enrolled 240 amnestic mild cognitive impairment patients, 240 non-amnestic mild cognitive impairment patients and 480 normal cognitive function controls. Data on admission and retrospective data at baseline (6 years ago) were collected from their medical records. Cognitive function was evaluated using Mini-Mental State Examination and Montreal Cognitive Assessment.

RESULTS

Being underweight, overweight or obese at baseline was associated with an increased risk of amnestic mild cognitive impairment (OR: 2.30, 95%CI: 1.50 ~ 3.52; OR: 1.74, 95%CI: 1.36 ~ 2.20; OR: 1.71, 95%CI: 1.32 ~ 2.22, respectively). Being overweight or obese at baseline was also associated with an increased risk of non-amnestic mild cognitive impairment (OR: 1.51, 95%CI: 1.20 ~ 1.92; OR: 1.52, 95%CI: 1.21 ~ 1.97, respectively). In subjects with normal weights at baseline, an increased or decreased body mass index at follow-up was associated with an elevated risk of amnestic mild cognitive impairment (OR: 1.80, 95%CI: 1.10 ~ 3.05; OR: 3.96, 95%CI: 2.88 ~ 5.49, respectively), but only an increased body mass index was associated with an elevated risk of non-amnestic mild cognitive impairment (OR: 1.71, 95%CI: 1.16 ~ 2.59).

CONCLUSIONS

Unhealthy body mass index levels at baseline and follow-up might impact the risk of both types of mild cognitive impairment (amnestic and non-amnestic).

T Cell Populations and Functions Are Altered in Human Obesity and Type 2 Diabetes

PURPOSE OF THE REVIEW

Obesity and type 2 diabetes (T2D) are considered chronic inflammatory diseases. While early publications have reported the implication of innate immune cells such as macrophages to promote systemic inflammation and metabolic dysfunctions, recent publications underline the alterations of the T cell compartment in human obesity and type 2 diabetes. These recent findings are the focus of this review.

RECENT FINDINGS

In humans, obesity and T2D induce the expansion of proinflammatory T cells such as CD4 Th1, Th17, and CD8 populations, whereas innate T cells such as MAIT and iNKT cells are decreased. These alterations reflect a loss of total T cell homeostasis that may contribute to tissue and systemic inflammation. Whether these changes are adaptive to nutritional variations and/or contribute to the progression of metabolic diseases remains to be clarified. T cell phenotyping may improve obese and/or T2D patient stratification with therapeutic and prognostic implications.

IL-17A-dependent gut microbiota is essential for regulating diet-induced disorders in mice

The gut microbiota plays a key role in obesity and related metabolic disorders, and multiple factors including diet, host genotype, and age regulate it. Many studies have examined the contribution of extrinsic factors to the regulation of the gut microbiota, but the importance of the host genetic constitution cannot be ignored. Interleukin 17A (IL-17A), a pro-inflammatory cytokine, is important in the defense against infection and diseases. Here, we investigated the association among IL-17, a high-fat diet (HFD), and the gut microbiota. Mice deficient in IL-17A were resistant to diet-induced obesity and related diseases. Compared with the Il-17a^-/- mice, wild-type (WT) mice challenged with HFD showed obvious weight fluctuations, such as those seen in type 2 diabetes, and hematological changes similar to those associated with metabolic syndrome. However, housing WT mice and Il-17a^-/- mice together significantly alleviated these symptoms in the WT mice. A metagenomic analysis of the mouse feces indicated that the microbial community compositions of these two groups differed before HFD feeding. The HFD mediated shifts in the gut microbial compositions, which were associated with the mouse phenotypes. We also identified potentially beneficial and harmful species present during this period, and drew networks of the most abundant species. A functional analysis indicated pathway changes in the WT and Il-17a^-/- mice when fed the HFD. Collectively, these data underscore the importance of the host factor IL-17A in shaping and regulating the gut microbiota, which conversely, influences the host health.

miRNAs in nutrition, obesity, and cancer: The biology of miRNAs in metabolic disorders and its relationship with cancer development

SCOPE

The scope of this review is to explain how metabolic disorders originated by a deficient nutrition can develop into a neoplastic process by the alteration of epigenetic mechanisms like miRNAs. Obesity is a proinflammatory state with a wide impact on health around the world that is associated with neoplastic diseases. Epigenetic mechanisms have a central role in the obesogenic environment, which participates on the development of comorbidities such as cancer.

METHODS AND RESULTS

We made an exhaustive review of the most recent reports about metabolic disorders with nutrition and their relationship with miRNAs, and their risk of developing into oncogenic processes. MicroRNAs (miRNAs) act as one of the major epigenetic mechanisms that can affect the metabolic reprogramming of cellular metabolism that plays an important role in the oncogenic process. There is evidence that some foods may contribute to diminishing the risk of cancer as well as epidemiological studies that support the notion that diets high in animal protein and fat promote cancer risk. Therefore, diets high in fruit and vegetables reduce the risk of cancer. One of the principal explanations is that these foods contain bioactive compounds that increase the efficacy of epigenetic mechanisms, which in turn decrease the risk of obesity and its comorbidities.

CONCLUSION

In this review, we show how miRNAs are implicated in several signaling pathways as well as illustrating some bioactive compounds that impact inflammation and cancer development.

Pathogenic Role of IL-17-Producing Immune Cells in Obesity, and Related Inflammatory Diseases

Obesity is associated with low-grade chronic inflammation. Indeed, adipose tissues (AT) in obese individuals are the former site of progressive infiltration by pro-inflammatory immune cells, which together with increased inflammatory adipokine secretion induce adipocyte insulin resistance. IL-17-producing T (Th17) cells are part of obese AT infiltrating cells, and are likely to be promoted by adipose tissue-derived mesenchymal stem cells, as previously reported by our team. Whereas Th17 cell are physiologically implicated in the neutralization of fungal and bacterial pathogens through activation of neutrophils, they may also play a pivotal role in the onset and/or progression of chronic inflammatory diseases, or cancer, in which obesity is recognized as a risk factor. In this review, we will highlight the pathogenic role of IL-17A producing cells in the mechanisms leading to inflammation in obesity and to progression of obesity-related inflammatory diseases.

Interleukin-18 polymorphism as an inflammatory index in metabolic syndrome: A preliminary study

AIM

To assess circulatory levels of interleukin-18 (IL-18) and determine whether the presence of IL-18 promoter polymorphism influences metabolic syndrome phenotypes.

METHODS

This study recruited one hundred and eighty individuals divided into three groups with sixty subjects each as: Normal weight (18.0-22.9 kg/m²), overweight (23.0-25.9 kg/m²) and obese (> 26.0 kg/m²) according to South Asian criteria of BMI. Fasting blood glucose (FBG), Lipid profile, insulin, IL-18 and tumor necrosis factor (TNF)α were measured using ELISA kits, whereas low density lipoprotein (LDL)-cholesterol, insulin resistance (HOMA-IR) and insulin sensitivity (QUICKI) were calculated. The body fat percentage (BF) was measured through bioelectrical impedance analysis; waist and hip circumference were measured. Genotyping of IL-18 -607 C/A polymorphism was performed by using tetra-primer amplification refractory mutation system. Student t test, One-way analysis of variance, Hardy-Weinberg equilibrium, Pearson’s χ² test and Pearson’s correlation were used, where a P value < 0.05 was considered significant.

RESULTS

In an aged matched study, obese subjects showed higher levels of FBG, cholesterol, triglycerides and LDL levels as compared to normal weight (P < 0.001). Highest levels of IL-18 and TNF levels were also seen in obese subjects (IL-18: 58.87 ± 8.59 ng/L) (TNF: 4581.93 ± 2132.05 pg/mL). The percentage of IL-18 -607 A/A polymorphism was higher in overweight and obese subjects vs normal weight subjects (P < 0.001). Moreover, subjects with AA genotype had a higher BF, insulin resistance, TNFα and IL-18 levels when compared with subjects with AC (heterozygous) or CC (wild type) genotypes. However, we did not find any difference in the lipid profile between three subgroups.

CONCLUSION

This preliminary data suggests that IL-18 polymorphism affects IL-18 levels that might cause low grade inflammation, further exacerbated by increased TNFα. All these increase the susceptibility to develop MetS. Further studies are required to validate our findings.

Gut-Specific Delivery of T-Helper 17 Cells Reduces Obesity and Insulin Resistance in Mice

BACKGROUND & AIMS

Obesity and metabolic syndrome have been associated with alterations to the intestinal microbiota. However, few studies examined the effects of obesity on the intestinal immune system. We investigated changes in subsets of intestinal CD4⁺ T-helper (T_H) cells with obesity and the effects of gut-tropic T_H17 cells in mice on a high-fat diet (HFD).

METHODS

We isolated immune cells from small intestine and adipose tissue of C57BL/6 mice fed a normal chow diet or a HFD for 10 weeks and analyzed the cells by flow cytometry. Mice fed a vitamin A-deficient HFD were compared with mice fed a vitamin A-sufficient HFD. Obese RAG1-deficient mice were given injections of only regulatory T cells or a combination of regulatory T cells and T_H17 cells (wild type or deficient in integrin β7 subunit or interleukin 17 [IL17]). Mice were examined for weight gain, fat mass, fatty liver, glucose tolerance, and insulin resistance. Fecal samples were collected before and after T cell transfer and analyzed for microbiota composition by metagenomic DNA sequencing and quantitative polymerase chain reaction.

RESULTS

Mice placed on a HFD became obese, which affected the distribution of small intestinal CD4⁺ T_H cells. Intestinal tissues from obese mice had significant reductions in the proportion of T_H17 cells but increased proportion of T_H1 cells, compared with intestinal tissues from nonobese mice. Depletion of vitamin A in obese mice further reduced the proportion of T_H17 cells in small intestine; this reduction correlated with more weight gain and worsening of glucose intolerance and insulin resistance. Adoptive transfer of in vitro-differentiated gut-tropic T_H17 cells to obese mice reduced these metabolic defects, which required the integrin β7 subunit and IL17. Delivery of T_H17 cells to intestines of mice led to expansion of commensal microbes associated with leanness.

CONCLUSIONS

In mice, intestinal T_H17 cells contribute to development of a microbiota that maintains metabolic homeostasis, via IL17. Gut-homing T_H17 cells might be used to reduce metabolic disorders in obese individuals.

The obesity-related pathology and Th17 cells

Chronic inflammation associated with obesity plays a major role in the development of metabolic diseases, cancer, and autoimmune diseases. Among Th subsets, Th17 cells are involved in the pathogenesis of autoimmune disorders such as psoriasis, rheumatoid arthritis, inflammatory bowel disease, steroid-resistant asthma, and multiple sclerosis. Accumulating data suggest that reciprocal interactions between the metabolic systems and immune system play pivotal roles in the pathogenesis of obesity-associated diseases. We herein outline the developing principles in the control of T cell differentiation and function via their cellular metabolism. Also discussed are recent findings that changes in the intracellular metabolism, including fatty acid metabolism, affect the Th17 cell function in obese individuals. Finally, we will also highlight the unique molecular mechanism involved in the activation of retinoid-related orphan receptor-gamma-t (RORγt) by intracellular metabolism and discuss a new therapeutic approach for treating autoimmune disorders through the inhibition of RORγt.

Immunometabolic Regulation of Interleukin-17-Producing T Helper Cells: Uncoupling New Targets for Autoimmunity

Interleukin-17-producing T helper (Th17) cells are critical for the host defense of bacterial and fungal pathogens and also play a major role in driving pathogenic autoimmune responses. Recent studies have indicated that the generation of Th17 cells from naïve CD4⁺ T cells is coupled with massive cellular metabolic adaptations, necessary to cope with different energy and metabolite requirements associated with switching from a resting to proliferative state. Furthermore, Th17 cells have to secure these metabolic adaptations when facing nutrient-limiting environments, such as at the sites of inflammation. Accumulating data indicates that this metabolic reprogramming is significantly linked to the differentiation of T helper cells and, particularly, that the metabolic changes of Th17 cells and anti-inflammatory Forkhead box P3⁺ regulatory T cells are tightly and reciprocally regulated. Thus, a better understanding of these processes could offer potential new targets for therapeutic interventions for autoimmune diseases. In this mini-review, we will highlight some of the recent advances and discoveries in the field, with a particular focus on metabolic demands of Th17 cells and their implications for autoimmunity.

Interleukin-17A exacerbates high-fat diet-induced hepatic steatosis by inhibiting fatty acid β-oxidation

There is a growing body of evidence that the interleukin-17A (IL-17A) signaling pathway contributes to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the mechanism by which IL-17A signaling induces hepatocyte injury is unclear. The aim of the present study was to investigate the significance of the IL-17A axis in NAFLD and to explore the role of IL-17A in high-fat diet (HFD)-induced NAFLD in C57BL/6 mice and oleic acid (OA)-induced lipid accumulation in hepatocytes. Firstly, Consistent upregulation of IL-17A was observed in the HFD-induced steatosis mice but not the normal chow-fed control mice. Administration of IL-17A impaired liver function, aggravated hepatic lipid accumulation by inhibiting fatty acid oxidation in the HFD mice. Conversely, inhibition of IL-17A using an anti-IL-17A monoclonal antibody (mAb) significantly attenuated HFD-induced liver injury. Furthermore, IL-17A accelerated hepatic steatosis through activation of the JNK-PPARα pathway in the HFD mice and OA-preloaded hepatocytes.

CONCLUSION

The present study demonstrated that a high fat diet induces IL-17A expression, which exacerbates the progression of NAFLD by inhibiting fatty acid β-oxidation and promoting the accumulation of triglycerides (TG).

Th17 cell frequency and IL-17A concentrations in peripheral blood mononuclear cells and vitreous fluid from patients with diabetic retinopathy

Objective To quantify T helper (Th)17 cells and determine interleukin (IL)-17A levels in peripheral blood mononuclear cell (PBMC) culture and vitreous fluid from patients with type 2 diabetes mellitus (T2DM) with diabetic retinopathy (DR). Methods Th17 cell frequency and IL-17A concentrations in PBMCs from 60 patients with T2DM with DR, 30 without DR and 30 sex- and age-matched healthy individuals were measured by flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively. IL-17A levels in vitreous fluid from 31 eyes with proliferative DR and diabetic macular oedema (DR group) and 32 eyes with an epiretinal membrane and macular hole (control group) that underwent vitrectomy were also examined by ELISA. Results Compared with the control group, the proportion of Th17 cells and IL-17A concentrations in PBMCs were significantly increased in patients without DR but decreased in those with DR. IL-17A concentrations and Th17 cell frequency in PBMCs tended to decrease with DR severity and were negatively correlated with body mass index, T2DM duration and glycated haemoglobin. Additionally, vitreous fluid IL-17A levels were significantly elevated in patients with DR compared with those of the control group. Conclusions We conclude that disturbances in Th17 cells and IL-17A levels are possibly associated with DR.

MicroRNA-26a-interleukin (IL)-6-IL-17 axis regulates the development of non-alcoholic fatty liver disease in a murine model

Non-alcoholic fatty liver disease (NAFLD) is a hepatic presentation of obesity and metabolic syndrome. MicroRNA 26a (Mir-26a) has been reported to play functions in cellular differentiation, cell growth, cell apoptosis and metastasis. A recent paper indicated that Mir-26a regulated insulin sensitivity and metabolism of glucose and lipids. However, the role of Mir-26a in NAFLD still needs to be investigated further. In our current study, vectors encoding pre-Mir-26a (LV-26a) and an empty lentiviral vector (LV-Con) delivered approximately 2 × 10⁷ transforming units of recombinant lentivirus were injected into mice through the tail vein. LV-26a-infected mice were protected from glucose dysmetabolism and showed markedly decreased total liver weight, hepatic triglyceride deposition and serum alanine transaminase (ALT) concentration when compared with LV-Con-treated mice. LV-26a-treated mice also exhibited decreased infiltration of immune cells in the liver - something attributed to reduce infiltration of T cell receptor (TCR)-γδ⁺ , granulocyte-differentiation antigen-1 (Gr-1)⁺ cells and CD11b⁺ cells. Next, we found that Mir-26a inhibited the expression of interleukin (IL)-17 and IL-6 in vivo and in vitro. Furthermore, the decreased expression of IL-17 in the liver tissue induced by Mir-26a was abrogated completely by IL-6 overexpression. The decreased total liver weight, hepatic triglyceride deposition and serum ALT concentration induced by Mir-26a was also abrogated completely by IL-6 over-expression. In conclusion, the Mir-26a-IL-6-IL-17 axis regulates the development of NAFLD in a murine model.