CD4+ T lymphocytes produce adiponectin in response to transplants

Functional Haplotypes in the ADIPOQ Gene are Associated with Underweight, Immunosuppression and Viral Suppression in Kenyan HIV-1 Infected Antiretroviral Treatment Naive and Experienced Injection Substance Users

Background

Human immunodeficiency virus and injection substance use have an influence on genes and gene expression. These effects could be beneficial or detrimental in defining disease outcomes. Adiponectin gene is key in modulating metabolic and immunoregulatory functions. Understanding the effects of human immunodeficiency virus and injection substance use on the gene in the context of antiretroviral therapy is important for predicting disease outcomes.

Methods

This cross-sectional genetic study determined polymorphisms in the promoter region of adiponectin gene. Two variants were analyzed: rs2241766 and rs266729. Polymorphisms were associated with clinical markers of disease outcome; underweight, immunosuppression and viral suppression. The variants were genotyped via random fragment length polymorphism.

Result

GC haplotype was associated with higher odds of having underweight (OR, 2.21; 95% CI, 1.83-4.60; P=0.008 vs. OR, 2.30; 95% CI, 1.89-4.71; P=0.006) in antiretroviral treatment - naive and experienced injection substance users and immunosuppression (OR, 1.90; 95% CI 1.67-3.98, P=0.041) in naive. Bonferroni correction revealed GC haplotype carriers only to have low body mass index in both naive (median, 14.8; IQR, 3.2 kg/m²; P=0.002) and experienced (median, 15.2; IQR, 3.2 kg/m²; P=0.002) injection substance users. Circulating total adiponectin levels were higher in naive (median, 19.5; IQR, 7.9 µg/ml) than - experienced (median, 12.0; IQR, 4.4 µg/ml) injection substance users (P=0.0001). GC carriers presented with low serum adiponectin levels in both study groups.

Conclusion

The study revealed haplotypes of adiponectin gene at loci rs2241766 and rs266729 that could determine disease outcomes in human immunodeficiency virus -1 antiretroviral treatment- naive and experienced injection substance users.

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.

Cell type-specific mechanisms coupling protease-activated receptor-1 to infectious colitis pathogenesis

BACKGROUND

Protease-activated receptor-1 (PAR-1) plays a major role in multiple disease processes, including colitis. Understanding the mechanisms coupling PAR-1 to disease pathogenesis is complicated by the fact that PAR-1 is broadly expressed across multiple cell types.

OBJECTIVE

Determine the specific contributions of PAR-1 expressed by macrophages and colonic enterocytes to infectious colitis.

METHODS

Mice carrying a conditional PAR-1 allele were generated and bred to mice expressing Cre recombinase in a myeloid- (PAR-1ΔM ) or enterocyte-specific (PAR-1ΔEPI ) fashion. Citrobacter rodentium colitis pathogenesis was analyzed in mice with global PAR-1 deletion (PAR-1-/- ) and cell type-specific deletions.

RESULTS

Constitutive deletion of PAR-1 had no significant impact on weight loss, crypt hypertrophy, crypt abscess formation, or leukocyte infiltration in Citrobacter colitis. However, colonic shortening was significantly blunted in infected PAR-1-/- mice, and these animals exhibited decreased local levels of IL-1β, IL-22, IL-6, and IL-17A. In contrast, infected PAR-1ΔM mice lost less weight and had fewer crypt abscesses relative to controls. PAR-1ΔM mice had diminished CD3+ T cell infiltration into colonic tissue, but macrophage and CD4+ T cell infiltration were similar to controls. Also contrasting results in global knockouts, PAR-1ΔM mice exhibited lower levels of IL-1β, but not Th17-related cytokines (ie, IL-22, IL-6, IL-17A). Infected PAR-1ΔEPI mice exhibited increased crypt hypertrophy and crypt abscess formation, but local cytokine elaboration was similar to controls.

CONCLUSIONS

These studies reveal complex, cell type-specific roles for PAR-1 in modulating the immune response to Citrobacter colitis that are not readily apparent in analyses limited to mice with global PAR-1 deficiency.

Adiponectin deficiency has no effect in murine autoimmune myocarditis

BACKGROUND

Adiponectin is a hormone that together with its receptors modulates a number of metabolic processes including gluconeogenesis and lipid catabolism. It belongs to the C1QTNF (complement C1q tumor necrosis factor-related protein) family, which has a variety of members with high amino acid sequence homology and overlapping functions. Concentration of adiponectin in blood is inversely correlated with body fat percentage and cardiac risk factors like blood pressure and CRP (C-reactive protein) level. Studies have identified the existence of a cardiac adiponectin system. However, little is known about the role of this system in the pathogenesis of autoimmune myocarditis. Thus, we have studied the involvement of adiponectin in the development of this autoimmune disorder in a mouse model of experimental autoimmune myocarditis (EAM).

METHODS

Adiponectin knockout (ko) and wild type (wt) mice were immunized with cardiac troponin I (cTnI) to induce an EAM. To determine the severity of myocardial damage, inflammation and fibrosis were scored after HE and Afog staining and high sensitivity troponin T (hsTnT) level was measured. To detect if changes in specific inflammatory cell numbers could be observed between the genotypes, we performed immunohistochemical staining to detect T lymphocytes, B lymphocytes and macrophages. The level of the humoral immune response was determined through the measurement of cTnI-specific serum IgG autoantibodies. Relative mRNA expression of different cytokines, C1QTNF family members and adiponectin receptors in the heart tissue was analyzed with qPCR.

RESULTS

Animals immunized with cTnI developed autoimmune myocarditis with a significant deterioration of cardiac parameters compared to the corresponding control group. The adiponectin ko group immunized with cTnI showed a tendency towards increased inflammation, fibrosis, heart-to-body-weight ratio, infiltration pattern of T lymphocytes, B lymphocytes and macrophages, hsTnT concentration, humoral immune response and mRNA expression of interleukin 6 in the heart tissue and decreased weight gain compared to the wt group immunized with cTnI. However, the difference to the wt group treated with cTnI was not significant. The analysis of cardiac mRNA expression of adiponectin receptors and four C1QTNF family members, most suitable for fulfilling the functions of adiponectin in adiponectin ko mice, did not show any significant differences between adiponectin ko and wt group at all.

CONCLUSION

Our study reveals that the absence of adiponectin did not lead to a significantly increased impairment of cardiac function and was also unlikely to be compensated by its receptors or other C1QTNF family members in the murine model of EAM. Here, other synergistic or redundant effects might play a role and must be investigated in further studies to understand the role and function of adiponectin in autoimmune myocarditis.

Sex Differences in the Associations of Obesity With Hypothyroidism and Thyroid Autoimmunity Among Chinese Adults

There is an intensive link between obesity and thyroid dysfunction, but this relationship in Asians is still unclear. This study was conducted to define the impact of obesity on risk of hypothyroidism and thyroid autoimmunity among Chinese adults. A population-based, cross-sectional study was carried out, which enrolled a total of 2,808 Chinese adults. To assess the associations of obesity with hypothyroidism and thyroid autoimmunity, odds ratio (ORs) with 95% confidence intervals (95%CIs) were calculated through logistic regression model, and the correlations of body mass index (BMI) with TPOAb and TGAb were also analyzed. Obese females had higher risk of hypothyroidism (22.7 vs. 15.0%; OR = 1.66, 95%CI 1.10–2.53; P = 0.02) and higher risk of subclinical hypothyroidism (22.1 vs. 13.4%; OR = 1.83, 95%CI 1.20–2.80; P = 0.005) than non-obese females. Multivariate logistic regression analysis found significant associations of obesity with hypothyroidism (Adjusted OR = 1.54, 95%CI 1.00–2.38; P = 0.05) and subclinical hypothyroidism (Adjusted OR = 1.69, 95%CI 1.09–2.63; P = 0.02) in females after adjustment for confounding factors. No association between obesity and hypothyroidism was observed in male participants. Spearman's correlation analysis suggested BMI was significantly and positively correlated with TPOAb (Spearman's r = 0.062, P = 0.022) in men but not in women. Linear regression analysis suggested an obviously positive correlation of BMI with TPOAb in men (β = 0.018, P = 0.015) and an obviously negative correlation of BMI with TGAb in women (β = −0.025, P = 0.012), respectively. The study suggests sex differences in the associations of obesity with hypothyroidism and thyroid autoimmunity among Chinese adults. Further studies are needed to better understand the exact mechanism of sex difference in the obesity-thyroid relationship.

CD4+ T Cells Have a Permissive Effect on Enriched Environment-Induced Hippocampus Synaptic Plasticity

Living in an enriched environment (EE) benefits health by acting synergistically on various biological systems including the immune and the central nervous systems. The dialog between the brain and the immune cells has recently gained interest and is thought to play a pivotal role in beneficial effects of EE. Recent studies show that T lymphocytes have an important role in hippocampal plasticity, learning, and memory, although the precise mechanisms by which they act on the brain remain elusive. Using a mouse model of EE, we show here that CD4⁺ T cells are essential for spinogenesis and glutamatergic synaptic function in the CA of the hippocampus. However, CD4⁺ lymphocytes do not influence EE-induced neurogenesis in the DG of the hippocampus, by contrast to what we previously demonstrated for CD8⁺ T cells. Importantly, CD4⁺ T cells located in the choroid plexus have a specific transcriptomic signature as a function of the living environment. Our study highlights the contribution of CD4⁺ T cells in the brain plasticity and function.