Selenium supplementation suppresses immunological and serological features of lupus in B6.Sle1b mice

Selenoproteome depletion enhances oxidative stress and alters neutrophil functions in Citrobacter rodentium infection leading to gastrointestinal inflammation

Reactive oxygen species (ROS) play a critical role in modulating a range of proinflammatory functions in neutrophils, as well as regulating neutrophil apoptosis and facilitating the resolution of an inflammatory response. Selenoproteins with the 21st amino acid, selenocysteine (Sec), regulate immune mechanisms through the modulation of redox homeostasis aiding in the efficient resolution of inflammation, while their role in neutrophil functions during diseases remains unclear. To study the role of selenoproteins in neutrophils during infection, we challenged the granulocyte-specific tRNASec (Trsp) knockout mice (TrspN) with Citrobacter rodentium (C. rodentium), a murine pathogenic bacterium. Reduced bacterial shedding during the disease-clearing phase and increased tissue damage and neutrophil accumulation in the colon of the TrspN mice were observed following infection. TrspN neutrophils showed increased intracellular ROS accumulation during ex vivo C. rodentium stimulation and upregulated fMLP or Cx3cl1-induced chemotaxis. We also observed delayed neutrophil apoptosis, reduced efferocytosis of TrspN neutrophils, and increased abundance of apoptotic cells in the colon of TrspN mice. Together, these studies indicate that selenoprotein depletion results in increased neutrophil migration to the gut accompanied by ROS accumulation, while downregulating neutrophil apoptosis and subsequent efferocytosis by macrophages. Such an increase in inflammation followed by impaired resolution culminates in decreased bacterial load but with exacerbated host tissue damage.

The correlation between single and mixed trace elements exposure in systemic lupus erythematosus: A case-control study

BACKGROUND

Recent studies have shown an association between trace elements and systemic lupus erythematosus (SLE), but the relationship between trace elements and SLE is still unclear. This study aims to determine the distribution of plasma trace elements in newly diagnosed SLE patients and the association between these essential and toxic element mixtures and SLE.

METHODS

In total, 110 SLE patients and 110 healthy controls were included. Blood samples were collected. 15 plasma trace elements were quantified using an inductively coupled plasma mass spectrometer (ICP-MS). Multivariate logistic regression, restricted cubic spline (RCS), weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) are used to analyze the association between single and mixed exposure of elements and SLE.

RESULTS

The logistic regression model shows that, plasma lithium (Li) [OR (95 % CI): 1.963 (1.49-2.586)], vanadium (V) [OR (95 % CI): 2.617(1.645-4.166)] and lead (Pb) [OR (95 % CI): 1.603(1.197-2.145)] were positively correlated with SLE, while selenium (Se) [OR (95 % CI): 0.055(0.019-0.157)] and barium (Ba) [OR (95 % CI): 0.792(0.656-0.957)] had been identified as protective factors for SLE. RCS results showed a non-linear correlation between the elements Li, V, Ni, copper, Se, rubidium and SLE. In addition, WQS regression, qgcomp, and BKMR models consistently revealed significant positive effects of plasma Li and Pb on SLE, as well as significant negative effects of plasma Se.

CONCLUSIONS

Exposure to heavy metals such as Li and Pb is significantly positively correlated with SLE, but Se may be protective factors for SLE. In addition, there is a nonlinear correlation between the elements Li and Se and SLE, and there are complex interactions between the elements. In the future, larger populations and prospective studies are needed to confirm these associations.

A Review of the Potential Benefits of Herbal Medicines, Small Molecules of Natural Sources, and Supplements for Health Promotion in Lupus Conditions

The Latin word lupus, meaning wolf, was in the medical literature prior to the 1200s to describe skin lesions that devour flesh, and the resources available to physicians to help people were limited. The present text reviews the ethnobotanical and pharmacological aspects of medicinal plants and purified molecules from natural sources with efficacy against lupus conditions. Among these molecules are artemisinin and its derivatives, antroquinonol, baicalin, curcumin, emodin, mangiferin, salvianolic acid A, triptolide, the total glycosides of paeony (TGP), and other supplements such as fatty acids and vitamins. In addition, medicinal plants, herbal remedies, mushrooms, and fungi that have been investigated for their effects on different lupus conditions through clinical trials, in vivo, in vitro, or in silico studies are reviewed. A special emphasis was placed on clinical trials, active phytochemicals, and their mechanisms of action. This review can be helpful for researchers in designing new goal-oriented studies. It can also help practitioners gain insight into recent updates on supplements that might help patients suffering from lupus conditions.

Nutritional Approaches to Modulate Cardiovascular Disease Risk in Systemic Lupus Erythematosus: A Literature Review

Systemic lupus erythematosus (SLE) is a chronic pathology characterized by a bimodal mortality pattern attributed to clinical disease activity and cardiovascular disease (CVD). A complex interaction between traditional CVD risk factors such as obesity, dyslipidemia, smoking, insulin resistance, metabolic syndrome, and hypertension, as well as the presence of non-traditional CVD risk factors such as hyperhomocysteinemia, pro-inflammatory cytokines, and C-reactive protein levels, has been suggested as a cause of the high prevalence of CVD in SLE patients. On the other hand, environmental factors, such as nutritional status, could influence the disease's prognosis; several nutrients have immunomodulators, antioxidants, and anti-cardiometabolic risk properties which could reduce SLE severity and organ damage by decreasing the development of traditional and non-traditional CVD risk factors. Therefore, this critical literature review discusses the therapeutic potential of nutritional approaches that could modulate the development of the main comorbidities related to CVD risk in SLE patients.

Immunometabolic alterations in lupus: where do they come from and where do we go from there?

Systemic lupus erythematosus (SLE) is an autoimmune disease in which the overactivation of the immune system has been associated with metabolic alterations. Targeting the altered immunometabolism has been proposed to treat SLE patients based on their results obtained and mouse models of the disease. Here, we review the recent literature to discuss the possible origins of the alterations in the metabolism of immune cells in lupus, the dominant role of mitochondrial defects, technological advances that may move the field forward, as well as how targeting lupus immunometabolism may have therapeutic potential.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Selenium donor restricts the intracellular growth of Mycobacterium tuberculosis through the induction of c-Jun-mediated both canonical autophagy and LC3-associated phagocytosis of alveolar macrophages

The relationship between selenium and Mycobacterium tuberculosis (MTB) infection has been reported previously; however, the specific mechanism is still not clear. In this study, selenium levels decreased in the serum of patients with pulmonary tuberculosis (PTB) compared with the healthy controls; they were associated with the treatment outcome of such patients. The qRT-PCR assay revealed that selenium might function through proinflammatory and autophagy pathways. The treatment with methylseleninic acid (MSeA), a selenium donor, blocked the M1 polarization of MTB-infected macrophages through the induction of both canonical autophagy and LC3-associated phagocytosis (LAP). c-Jun is vital in mediating the MSeA-triggered canonical autophagy and LAP process, thus displaying a restricting function against intracellular MTB. An in vivo study confirmed that the activity of MSeA was shown through enhancing macrophage autophagy related pathway. The results showed that selenium had a restricting function against intracellular MTB by regulating autophagy in macrophages. The findings might provide a novel direction for PTB therapy in the future.

Supranutritional selenium suppresses ROS-induced generation of RANKL-expressing osteoclastogenic CD4+ T cells and ameliorates rheumatoid arthritis

OBJECTIVE

The benefit of Se supplementation in rheumatoid arthritis (RA) has been tested in clinical trials, but results remain inconclusive. The objective of this study was to specifically investigate the potential benefit of supranutritional Se by examining human samples from an area with supranutritional Se intake and testing a mouse model of RA.

METHODS

Peripheral blood mononuclear cells (PBMCs) from RA patients (N = 57) and healthy controls (HC, N = 71) from an area of supranutritional Se intake (Enshi, Hubei, China) were analysed by flow cytometry. Serum cytokine and Se levels were measured by cytometric beads array (CBA) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. With sufficient or supranutritional selenium intake, mice were induced with collagen-induced arthritis (CIA) and examined for disease activity and immunopathology. The influence of Se supplementation in the generation of RANKL-expressing osteoclastogenic CD4+ T cells was investigated by in vitro assays.

RESULTS

In Enshi city, HC showed the above-normal concentrations of serum Se concentrations while RA patients were enriched in the normal range (70-150 ng mL-1) or below. RA patients with higher Se levels demonstrated milder disease and lower levels of C-reactive protein, IL-6, RANKL and Th17 cells. In the mouse CIA model, supranutritional Se supplementation delayed disease onset, ameliorated joint pathology and reduced CD4+CD44+RANKL+ T cells. Se supplementation could suppress RANKL expression in cultured mouse Th17 cells.

CONCLUSION

Supranutritional Se suppresses RANKL-expressing osteoclastogenic CD4+ T cells and could be beneficial to RA, which warrants formal testing in randomised clinical trials.

MiR-146b-5p targets IFI35 to inhibit inflammatory response and apoptosis via JAK1/STAT1 signalling in lipopolysaccharide-induced glomerular cells

The dysregulated microRNAs (miRNAs) are implicated in the malignancy of lupus nephritis (LN). This work aims to analyse the effect and mechanism of miR-146b-5p in lipopolysaccharides (LPS)-induced model of LN in vitro. The serum samples of LN patients and normal volunteers were collected. HK-2 cells were challenged via LPS. miR-146b-5p and interferon-induced protein 35 (IFI35) abundances were detected via quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The inflammatory response was assessed via inflammatory cytokines levels via qRT-PCR and enzyme-linked immunosorbent assay. Cell apoptosis was analysed via flow cytometry and apoptotic protein levels. The protein levels of JAK1/STAT1 signalling were detected via western blot. The relationship of miR-146b-5p and IFI35 was analysed via bioinformatics and dual-luciferase reporter assays. This study revealed that miR-146b-5p level was declined and IFI35 abundance was elevated in serum of LN patients and LPS-challenged HK-2 cells. Functionally, IFI35 overexpression promoted LPS-caused inflammatory response and cell apoptosis, and knockdown of IFI35 caused an opposite trend. Meanwhile, miR-146b-5p targeted IFI35 to suppress inflammatory response and cell inflammatory response and apoptosis via inactivating the JAK1/STAT1 pathway. MiR-146b-5p suppressed inflammatory response and cell apoptosis by IFI35 mediated-JAK1/STAT1 signalling in HK-2 cells, which provided a new mechanism for understanding the pathogenesis of LN.

Autoimmunity in 2019

Based on the PubMed data, we have been performing a yearly evaluation of the publications related to autoimmune diseases and immunology to ascertain the relative weight of the former in the scientific literature. It is particularly intriguing to observe that despite the numerous new avenues of immune-related mechanisms, such as cancer immunotherapy, the proportion of immunology manuscripts related to autoimmunity continues to increase and has been approaching 20% in 2019. As in the previous 13 years, we performed an arbitrary selection of the peer-reviewed articles published by the major dedicated Journals and discussed the common themes which continue to outnumber peculiarites in autoimmune diseases. The investigated areas included systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriatic arthritis (PsA), autoantibodies (autoAbs), and common therapeutic avenues and novel pathogenic mechanisms for autoimmune conditions. Some examples include new pathogenetic evidence which is well represented by IL21 or P2X7 receptor (P2X7R) in SLE or the application of single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq), and flow cytometry for the analysis of different cellular populations in RA. Cumulatively and of interest to the clinicians, a large number of findings continue to underline the importance of a strict relationship between basic and clinical science to define new pathogenetic and therapeutic developments. The therapeutic pipeline in autoimmunity continues to grow and maintain a constant flow of new molecules, as well illustrated in RA and PsA, and this is most certainly derived from the new basic evidence and the high-throughput tools applied to autoimmune diseases.

Selenium Modulates the Allergic Response to Whey Protein in a Mouse Model for Cow's Milk Allergy

Cow's milk allergy is a common food allergy in infants, and is associated with an increased risk of developing other allergic diseases. Dietary selenium (Se), one of the essential micronutrients for humans and animals, is an important bioelement which can influence both innate and adaptive immune responses. However, the effects of Se on food allergy are still largely unknown. In the current study it was investigated whether dietary Se supplementation can inhibit whey-induced food allergy in an animal research model. Three-week-old female C3H/HeOuJ mice were intragastrically sensitized with whey protein and cholera toxin and randomly assigned to receive a control, low, medium or high Se diet. Acute allergic symptoms, allergen specific immunoglobulin (Ig) E levels and mast cell degranulation were determined upon whey challenge. Body temperature was significantly higher in mice that received the medium Se diet 60 min after the oral challenge with whey compared to the positive control group, which is indicative of impaired anaphylaxis. This was accompanied by reductions in antigen-specific immunoglobulins and reduced levels of mouse mast cell protease-1 (mMCP-1). This study demonstrates that oral Se supplementation may modulate allergic responses to whey by decreasing specific antibody responses and mMCP-1 release.

Genetically determined selenium concentrations and risk for autoimmune diseases

OBJECTIVE

Observational epidemiologic studies have reported a relationship between selenium status and risk for autoimmune diseases. However, the associations are susceptible to confounding or reverse causality. Thus, the aim of this study was to investigate the potential causal associations of selenium concentrations with the risk for common autoimmune diseases using a two-sample Mendelian randomization (MR) design.

METHODS

A meta-analysis of genome-wide association studies (GWASs) of selenium among 9639 individuals of European ancestry was used to identify genetic instruments. Summary statistics of systemic lupus erythematosus, rheumatoid arthritis, and inflammatory bowel disease were obtained from publicly available GWASs, respectively. We conducted MR study using the inverse-variance weighted method, supplemented with weighted median and likelihood-based methods as sensitivity analysis. Cochran Q test and MR-Egger regression were used to detect heterogeneity and potential directional pleiotropy. MR-Pleiotropy RESidual Sum and Outlier test was used to identify outlier single-nucleotide polymorphisms.

RESULTS

Genetically predicted high selenium level was associated with a decreased risk for SLE (odds ratio, 0.85; 95% confidence interval, 0.77-0.93; P = 0.001) per natural log-transformed selenium concentrations, with similar results in sensitivity analyses. No evidence of heterogeneity, pleiotropy, or outlier single-nucleotide polymorphisms were detected (all P > 0.05). However, genetically determined selenium concentrations may be not associated with risk for rheumatoid arthritis or inflammatory bowel disease in the primary analysis and subsequent sensitivity analyses.

CONCLUSIONS

The present study suggested a protective role of selenium on the risk for systemic lupus erythematosus. Further studies are warranted to elucidate the underlying mechanisms.

Selenization of S. cerevisiae increases its protective potential in experimental autoimmune encephalomyelitis by triggering an intestinal immunomodulatory loop

Multiple sclerosis is an autoimmune disease that affects the myelinated central nervous system (CNS) neurons and triggers physical and cognitive disabilities. Conventional therapy is based on disease-modifying drugs that control disease severity but can also be deleterious. Complementary medicines have been adopted and evidence indicates that yeast supplements can improve symptoms mainly by modulating the immune response. In this investigation, we evaluated the therapeutic potential of Saccharomyces cerevisiae and its selenized derivative (Selemax) in experimental autoimmune encephalomyelitis (EAE). Female C57BL/6 mice submitted to EAE induction were orally supplemented with these yeasts by gavage from day 0 to day 14 after EAE induction. Both supplements determined significant reduction in clinical signs concomitantly with diminished Th1 immune response in CNS, increased proportion of Foxp3+ lymphocytes in inguinal and mesenteric lymph nodes and increased microbiota diversity. However, Selemax was more effective clinically and immunologically; it reduced disease prevalence more sharply, increased the proportion of CD103+ dendritic cells expressing high levels of PD-L1 in mesenteric lymph nodes and reduced the intestinal inflammatory process more strongly than S. cerevisiae. These results suggest a clear gut-brain axis modulation by selenized S. cerevisiae and suggest their inclusion in clinical trials.

Immunomodulatory Effects of Diet and Nutrients in Systemic Lupus Erythematosus (SLE): A Systematic Review

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ involvement, including the skin, joints, kidneys, lungs, central nervous system and the haematopoietic system, with a large number of complications. Despite years of study, the etiology of SLE remains unclear; thus, safe and specifically targeted therapies are lacking. In the last 20 years, researchers have explored the potential of nutritional factors on SLE and have suggested complementary treatment options through diet. This study systematically reviews and evaluates the clinical and preclinical scientific evidence of diet and dietary supplementation that either alleviate or exacerbate the symptoms of SLE. For this review, a systematic literature search was conducted using PubMed, Scopus and Google Scholar databases only for articles written in the English language. Based on the currently published literature, it was observed that a low-calorie and low-protein diet with high contents of fiber, polyunsaturated fatty acids, vitamins, minerals and polyphenols contain sufficient potential macronutrients and micronutrients to regulate the activity of the overall disease by modulating the inflammation and immune functions of SLE.