Sex-defined T-cell responses to cardiac self determine differential outcomes of murine dilated cardiomyopathy

Biological Sex As a Critical Variable in CD4+ Effector T Cell Function in Preclinical Models of Multiple Sclerosis

Significance: T cells play a pivotal role in maintaining adaptive immune responses against pathogens. However, misdirected T cell responses against self-tissues may lead to autoimmune disease. Biological sex has profound effects on T cell function and is an important determinant of disease incidence and severity in autoimmune diseases such as multiple sclerosis (MS). Recent Advances: Many autoimmune diseases skew toward higher female incidence, including MS; however, it is has become increasingly more accepted that men living with MS are more prone to developing a progressive disease course and to having worsened disease outcomes. Critical Issues: In this review, we discuss what is known about the role of biological sex on T cell development and differentiation, examining evidence that male sex can augment T helper 17 (Th17) responses. Next, we outline what is known about sex differences in animal models of MS, and about the distinct roles played by sex hormones versus sex chromosomes in pathogenesis in these models. Finally, we discuss recent advances that examine the molecular basis for worsened disease outcomes in males, with a particular focus on the role played by Th17 cells in these models. Future Directions: Better understanding the role of biological sex in T cell function may pave the way to effective personalized treatment strategies in MS and other autoimmune diseases. Antioxid. Redox Signal. 37, 135-149.

Male sex chromosomal complement exacerbates the pathogenicity of Th17 cells in a chronic model of central nervous system autoimmunity

Sex differences in multiple sclerosis (MS) incidence and severity have long been recognized. However, the underlying cellular and molecular mechanisms for why male sex is associated with more aggressive disease remain poorly defined. Using a T cell adoptive transfer model of chronic experimental autoimmune encephalomyelitis (EAE), we find that male Th17 cells induce disease of increased severity relative to female Th17 cells, irrespective of whether transferred to male or female recipients. Throughout the disease course, a greater frequency of male Th17 cells produce IFNγ, a hallmark of pathogenic Th17 responses. Intriguingly, XY chromosomal complement increases the pathogenicity of male Th17 cells. An X-linked immune regulator, Jarid1c, is downregulated in pathogenic male murine Th17 cells, and functional experiments reveal that it represses the severity of Th17-mediated EAE. Furthermore, Jarid1c expression is downregulated in CD4⁺ T cells from MS-affected individuals. Our data indicate that male sex chromosomal complement critically regulates Th17 cell pathogenicity.

LTBP2 knockdown by siRNA reverses myocardial oxidative stress injury, fibrosis and remodelling during dilated cardiomyopathy

AIM

Dilated cardiomyopathy (DCM) is characterised by left ventricular dilation and associated with systolic dysfunction. Recent evidence has reported the high expression of latent transforming growth factor beta binding protein 2 (LTBP2) in heart diseases, which may play a role in regulating multiple biological functions of myocardial cells. Thus, this study set out to investigate the molecular mechanism and effects of LTBP2 in myocardial oxidative stress injury, fibrosis and remodelling in a rat model of DCM, with the involvement of NF-κB signalling pathway.

METHODS

The rat model of DCM was treated with si-LTBP2 and/or activator of NF-κB signalling pathway to examine the haemodynamic indexes, cardiac functions, oxidative stress injury, fibrosis and remodelling. Moreover, in vitro experiments were conducted to verify the regulatory role of LTBP2 and NF-κB signalling pathway in DCM.

RESULTS

LTBP2 was up-regulated in DCM rats. After LTBP2 was knocked down, haemodynamic indexes, HW/BW ratio, collagen volume fraction (CVF) level, positive expression of LTBP2, levels of reactive oxygen species (ROS), malondialdehyde (MDA), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), tumour necrosis factor beta 1 (TGF-β1) and brain natriuretic peptide (BNP) were all decreased. Meanwhile, levels of LTBP2, Col-I, Col-III, p65 and p52 were also reduced, while HW, BW and levels of SOD and TAOC were increased. In contrast, activation of NF-κB signalling pathway reversed effects of LTBP2 gene silencing. These findings were confirmed by in vivo experiments.

CONCLUSIONS

LTBP2 silencing can attenuate myocardial oxidative stress injury, myocardial fibrosis and myocardial remodelling in DCM rats by down-regulating the NF-κB signalling pathway.

Analysis of IL-17 gene polymorphisms in Chinese patients with dilated cardiomyopathy

Cardiomyopathy is one of the major causes of sudden death and/or progressive heart failure. Dilated cardiomyopathy (DCM), comprising 60% of the cases of identified cardiomyopathy, is the most common form of heart muscle disease. Interleukin 17 (IL-17) is a proinflammatory cytokine that has been implicated in the pathogenesis of various diseases. To evaluate the influence of IL-17A and IL-17F gene polymorphisms on the risk of DCM, a case-control study was conducted in a Chinese Han population. The TaqMan® SNP Genotyping Assay was used to genotype the SNP rs2275913 of IL-17A and SNP rs763780 of IL-17F in 288 DCM patients and 421 ethnicity-matched controls. No significant difference in genotypic and allelic frequencies between DCM patients and control subjects was observed. However, Results of stratified analysis revealed that rs763780 was associated with male DCM patients in a dominant genetic model (p=0.031, OR=1.83, 95% CI=1.04-3.22). Our results suggest that the tested two IL-17 SNPs, rs2275913 and rs763780, are not found to be associated with DCM in the Chinese population studied.

Autoimmunity to uroplakin II causes cystitis in mice: a novel model of interstitial cystitis

BACKGROUND

The pathophysiology of interstitial cystitis (IC) is unknown. Deficits in urothelial cell layers and autoimmune mechanisms may play a role.

OBJECTIVE

To examine whether immunization of mice with recombinant mouse uroplakin II (rmUPK2), a bladder-specific protein, would provoke an autoimmune response sufficient to create an IC phenotype.

DESIGN, SETTING, AND PARTICIPANTS

RmUPK2 complementary DNA was generated, transferred into a bacterial expression vector, and the generated protein was purified. Eight-week-old SWXJ female mice were immunized with rmUPK2 protein via subcutaneous injection of 200μg of rmUPK2 protein in 200μl of an emulsion.

MEASUREMENTS

Mice were euthanized 5 wk after immunization. Axillary and inguinal lymph node cells were tested for antigen-specific responsiveness and cytokine production, serum isotype antibody titers against rmUPK2 were determined, and gene expression of inflammatory mediators was measured in the bladder and other organs. For functional analysis, mice were placed in urodynamic chambers for 24-h micturition frequency and total voided urine measurements.

RESULTS AND LIMITATIONS

Immunization with rmUPK2 resulted in T-cell infiltration of the bladder urothelium and increased rmUPK2-specific serum antibody responses in the experimental autoimmune cystitis (EAC) mice models compared with controls. The ratio of bladder to body weight was increased in EAC mice. Quantitative reverse transcriptase polymerase chain reaction analysis showed elevated gene expression of tumor necrosis factor α, interferon γ, interleukin (IL)-17A, and IL-1β in bladder urothelium but not in other organs. Evaluation of 24-h micturition habits of EAC mice showed significantly increased urinary frequency (p<0.02) and significantly decreased urine output per void (p<0.021) when compared with control mice.

CONCLUSIONS

Our study showed that a bladder-specific autoimmune response sufficient to induce inflammation and EAC occurs in mice following immunization with rmUPK2. EAC mice displayed significant evidence of urinary frequency and decreased urine output per void. Further phenotype characterization of EAC mice should include evidence for pain and/or afferent hypersensitivity, and evidence of urothelial cell layer damage.

The Treg/Th17 imbalance in patients with idiopathic dilated cardiomyopathy

To assess whether Treg/Th17 balance was broken in patients with idiopathic dilated cardiomyopathy (DCM). We studied 25 patients who were diagnosed as idiopathic DCM (18 men and seven women, mean age 35.6 +/- 5.2) and 25 normal persons (18 men and seven women, mean age 33.8 +/- 4.9). Then, we detected Treg/Th17 functions on different levels including cell frequencies, related cytokine secretion and key transcription factors in patients with idiopathic DCM and controls. The results demonstrated that patients with idiopathic DCM revealed significant increase in peripheral Th17 number, Th17-related cytokines (IL-17, IL-6, IL-23) and transcription factor (RORgammat) levels and obvious decrease in Treg number, Treg-related cytokines (TGF-beta1 and IL-10) and transcription factor (Foxp3) levels when compared to normal persons. Results indicated that Treg/Th17 functional imbalance existed in patients with idiopathic DCM, suggesting a potential role for Treg/Th17 imbalance in the development of idiopathic DCM.

Risk of autoimmune disease: challenges for immunotoxicity testing

Autoimmunity represents a potentially diverse and complex category among the range of adverse outcomes for detection with immunotoxicity testing. For this reason, the risk of autoimmune disease is discussed in this overview chapter with additional mention among the later specific protocol chapters. Improvements in clinical diagnostic capabilities and disease recognition have led to a more accurate picture of the extent of autoimmune diseases across different human populations. While the risk of any single autoimmune disease remains modest when compared with that of lung or heart disease, the cumulative prevalence of autoimmune diseases is both significant and increasing. Autoimmune diseases are usually viewed in the context of the damaged tissue or organ (e.g., as a thyroid, gastrointestinal, cardiovascular or neurological disease). But improved recognition that underlying immune dysfunction can connect the risks for these as well as other diseases is critical for optimizing risk assessment. Since autoimmune diseases are chronic in nature with many first appearing in children or in young adults, these diseases exert a serious impact on both health care costs and quality of life. This chapter provides a discussion of the issues that should be considered with immunotoxicity testing for risk of autoimmunity.