Predictive and protective autoimmunity in cardiovascular diseases: is vaccination therapy a reality?

Atg5 deficiency in basophils improves metabolism in lupus mice by regulating gut microbiota dysbiosis

Autophagic activation in immune cells, gut microbiota dysbiosis, and metabolic abnormalities have been reported separately as characteristics of systemic lupus erythematosus (SLE). Elucidating the crosstalk among the immune system, commensal microbiota, and metabolites is crucial to understanding the pathogenesis of autoimmune diseases. Emerging evidence shows that basophil activation plays a critical role in the pathogenesis of SLE; however, the underlying mechanisms remain largely unknown. Here, we investigated the effects of autophagic inhibition on the pathogenesis of basophils in SLE using Autophagy-related gene 5 (Atg5) knockout (Atg5-/-) as an autophagic inhibitor. Specifically, we knocked out basophilic Atg5 in vivo to investigate its impact on lupus metabolism. Furthermore, Atg5-/- basophils were transferred to basophil-depleted MRL/MpJ-Faslpr (MRL/lpr) mice to study their effect on disease metabolism. Metagenomic and targeted metabolomic sequencing results indicated considerable reduction in the levels of plasma autoantibodies and inflammatory cytokines in the Atg5-/- basophil transfer group compared with that in the control group. Transplanting Atg5-/- basophils improved the gut microbiota balance in MRL/lpr mice, increasing the abundance of beneficial bacteria, such as Ligilactobacillus murinus and Faecalitalea rodentium, and reducing that of potentially pathogenic bacteria such as Phocaeicola salanitronis. The transplantation of Atg5-deficient basophils improved lupus symptoms by modulating lipid and amino acid metabolism. This improvement was linked to changes in the gut microbiota, particularly an increase in Ligilactobacillus murinus and Faecalitalea rodentium populations. These microbial shifts are believed to promote the production of beneficial metabolites, such as γ-linolenic acid and oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine, while reducing the levels of harmful metabolites such as arginine. These alterations in the metabolic profile contribute to the alleviation of lupus symptoms. Collectively, these findings reveal a novel role of basophil autophagy in SLE, highlighting its potential as a therapeutic target.

Heat shock proteins and cardiovascular disease

Atherosclerosis is the leading global cause of mortality, morbidity, and disability. Heat shock proteins (HSPs) are a highly conserved family of proteins with diverse functions expressed by all cells exposed to environmental stress. Studies have reported that several HSPs may be potential risk markers of atherosclerosis and related cardiovascular diseases, or may be directly involved in the atherogenic process itself. HSPs are expressed by cells in atherosclerotic plaque and anti-HSP has been reported to be increased in patients with vascular disease. Autoimmune responses may be generated against antigens present within the atherosclerotic plaque, including HSP and may lead to a cycle of ongoing vascular injury. It has been suggested that by inducing a state of tolerance to these antigens, the atherogenic process may be limited and thus provide a potential therapeutic approach. It has been suggested that anti-HSPs are independent predictors of risk of vascular disease. In this review, we summarize the current understanding of HSP in cardiovascular disease and highlight their potential role as diagnostic agents and therapeutic targets.

Tracing environmental markers of autoimmunity: introducing the infectome

We recently introduced the concept of the infectome as a means of studying all infectious factors which contribute to the development of autoimmune disease. It forms the infectious part of the exposome, which collates all environmental factors contributing to the development of disease and studies the sum total of burden which leads to the loss of adaptive mechanisms in the body. These studies complement genome-wide association studies, which establish the genetic predisposition to disease. The infectome is a component which spans the whole life and may begin at the earliest stages right up to the time when the first symptoms manifest, and may thus contribute to the understanding of the pathogenesis of autoimmunity at the prodromal/asymptomatic stages. We provide practical examples and research tools as to how we can investigate disease-specific infectomes, using laboratory approaches employed from projects studying the “immunome” and “microbiome”. It is envisioned that an understanding of the infectome and the environmental factors that affect it will allow for earlier patient-specific intervention by clinicians, through the possible treatment of infectious agents as well as other compounding factors, and hence slowing or preventing disease development.

Antibodies as predictors of autoimmune diseases and cancer

BACKGROUND

Autoantibodies targeted against a variety of self-antigens are detected in autoimmune diseases and cancer. Emerging evidence has suggested the involvement of environmental factors such as infections and xenobiotics, and some dietary proteins and their antibodies in the pathogenesis of many autoimmune diseases. These antibodies appear in the blood years before presentation of symptoms in various disorders. Therefore, these antibodies may be used as biomarkers for early detection of various diseases.

OBJECTIVE

To provide an overview of antibody arrays that are measured against different human tissue antigens, crossreactive epitopes of infectious agents, dietary proteins, and haptenic chemicals in autoimmune diseases and cancer.

METHOD

Microarray analysis of antigen-antibody reaction.

CONCLUSION

The application of these antibody arrays to human autoimmune disease is expanding and is allowing for the identification of patterns or antibody signatures, thus establishing the premises for increased sensitivity and specificity of prediction, as well as positive predictive values. The presence of these antibodies would not necessarily mean that a patient would definitely become sick but may give a percentage of risk for different conditions that may develop over future months or years. Using this high-throughput microarray method, it is possible to screen rapidly for dozens of autoantibodies at low cost. This is an important factor in the implementation of autoantibody testing as a routine part of medical examinations.

Infectome: a platform to trace infectious triggers of autoimmunity

The "exposome" is a term recently used to describe all environmental factors, both exogenous and endogenous, which we are exposed to in a lifetime. It represents an important tool in the study of autoimmunity, complementing classical immunological research tools and cutting-edge genome wide association studies (GWAS). Recently, environmental wide association studies (EWAS) investigated the effect of environment in the development of diseases. Environmental triggers are largely subdivided into infectious and non-infectious agents. In this review, we introduce the concept of the "infectome", which is the part of the exposome referring to the collection of an individual's exposures to infectious agents. The infectome directly relates to geoepidemiological, serological and molecular evidence of the co-occurrence of several infectious agents associated with autoimmune diseases that may provide hints for the triggering factors responsible for the pathogenesis of autoimmunity. We discuss the implications that the investigation of the infectome may have for the understanding of microbial/host interactions in autoimmune diseases with long, pre-clinical phases. It may also contribute to the concept of the human body as a superorganism where the microbiome is part of the whole organism, as can be seen with mitochondria which existed as microbes prior to becoming organelles in eukaryotic cells of multicellular organisms over time. A similar argument can now be made in regard to normal intestinal flora, living in symbiosis within the host. We also provide practical examples as to how we can characterise and measure the totality of a disease-specific infectome, based on the experimental approaches employed from the "immunome" and "microbiome" projects.

The autoimmune origin of atherosclerosis

Atherosclerosis is a chronic inflammatory disease. Many studies and observations suggest that it could be caused by an immune reaction against autoantigens at the endothelial level, the most relevant of which are oxidized LDL and heat shock proteins (HSP) 60/65. Endothelial dysfunction plays a fundamental role. The first antigen is related to the increased leakage and oxidation of LDL; the second to cellular reaction to stress. Experimental and clinical observations confirm the pathogenetic role of these antigens. Both innate and adaptive immunity and impaired regulatory mechanisms of the autoimmune reaction are involved. Different triggering factors are examined: infectious agents, smoking, air pollution, diabetes and hypercholesterolemia. Analogies and differences between systemic atherosclerosis and transplant-related coronary atherosclerosis help to understand their respective nature. Immune mechanisms might be responsible for the passage from stable plaque to unstable and rupture-prone plaque. Finally, prospects of treatment and prevention are linked to the induction of tolerance to responsible antigens, activation of immune regulatory response and the use of immunomodulatory drugs.

OxLDL/beta2GPI-anti-oxLDL/beta2GPI complex and atherosclerosis in SLE patients

It has been demonstrated that atherosclerosis (ATS) is enhanced in autoimmune rheumatic diseases, such as systemic lupus erythematosus (SLE). The reason for this accelerated process is still debatable and, although traditional risk factors are more prevalent in SLE patients than in general population, they do not seem to fully explain the enhanced risk. ATS has the characteristics of an autoimmune chronic disease, involving both the innate and the adaptive immunity. Moreover, it satisfies the four criteria defining an autoimmune disease, proposed by Witebsky and Rose. It has been shown that some autoantibodies, including anti-oxLDL, anti-beta(2)GPI, anti-HSP60/65, and more recently anti-oxLDL/beta(2)GPI, play a key role in the pathogenesis of ATS. However the role of these autoantibodies in accelerated ATS in SLE patients is still controversial. In fact, some of them seem to be proatherogenic and other protective; moreover, it has been demonstrated that induced oral tolerance has a protective role against ATS. We have recently observed that the levels of oxLDL/beta(2)GPI antigenic complexes and their antibodies were higher in patients with SLE than in healthy subjects, but we did not find a clear association between oxLDL/beta(2)GPI complexes and IgG or IgM anti-oxLDL/beta(2)GPI autoantibodies and subclinical ATS in SLE patients. Many other studies are required to explain the role of autoantibodies in the pathogenesis of ATS in SLE patients, because the characteristics of SLE seem to mask their effects for atherogenesis.