Malarial infection of female BWF1 lupus mice alters the redox state in kidney and liver tissues and confers protection against lupus nephritis

The influence and therapeutic effect of microbiota in systemic lupus erythematosus

Systemic erythematosus lupus (SLE) is an autoimmune disease involving multiple organs that poses a serious risk to the health and life of patients. A growing number of studies have shown that commensals from different parts of the body and exogenous pathogens are involved in SLE progression, causing barrier disruption and immune dysregulation through multiple mechanisms. However, they sometimes alleviate the symptoms of SLE. Many factors, such as genetic susceptibility, metabolism, impaired barriers, food, and sex hormones, are involved in SLE, and the microbiota drives the development of SLE either by depending on or interacting with these factors. Among these, the crosstalk between genetic susceptibility, metabolism, and microbiota is a hot topic of research and is expected to lay the groundwork for the amelioration of the mechanism, diagnosis, and treatment of SLE. Furthermore, the microbiota has great potential for the treatment of SLE. Ideally, personalised therapeutic approaches should be developed in combination with more specific diagnostic methods. Herein, we provide a comprehensive overview of the role and mechanism of microbiota in lupus of the intestine, oral cavity, skin, and kidney, as well as the therapeutic potential of the microbiota.

Plasmodium curtails autoimmune nephritis via lasting bone marrow alterations, independent of hemozoin accumulation

The host response against infection with Plasmodium commonly raises self-reactivity as a side effect, and antibody deposition in kidney has been cited as a possible cause of kidney injury during severe malaria. In contrast, animal models show that infection with the parasite confers long-term protection from lethal lupus nephritis initiated by autoantibody deposition in kidney. We have limited knowledge of the factors that make parasite infection more likely to induce kidney damage in humans, or the mechanisms underlying protection from autoimmune nephritis in animal models. Our experiments with the autoimmune-prone FcγR2B[KO] mice have shown that a prior infection with P. yoelii 17XNL protects from end-stage nephritis for a year, even when overall autoreactivity and systemic inflammation are maintained at high levels. In this report we evaluate post-infection alterations, such as hemozoin accumulation and compensatory changes in immune cells, and their potential role in the kidney-specific protective effect by Plasmodium. We ruled out the role of pigment accumulation with the use of a hemozoin-restricted P. berghei ANKA parasite, which induced a self-resolved infection that protected from autoimmune nephritis with the same mechanism as parasitic infections that accumulated normal levels of hemozoin. In contrast, adoptive transfer experiments revealed that bone marrow cells were altered by the infection and could transmit the kidney protective effect to a new host. While changes in the frequency of bone marrow cell populations after infection were variable and unique to a particular parasite strain, we detected a sustained bias in cytokine/chemokine expression that suggested lower fibrotic potential and higher Th1 bias likely affecting multiple cell populations. Sustained changes in bone marrow cell activation profile could have repercussions in immune responses long after the infection was cleared.

Epidemiology of rheumatic diseases: a cohort of 23,550 patients in rheumatology clinics in Burkina Faso

OBJECTIVE

The aim of this work is to study the epidemiological characteristics of rheumatic conditions in a cohort of 23,550 patients followed up in Ouagadougou, Burkina Faso.

PATIENTS AND METHODS

This was a descriptive observational study on records conducted from February 2006 to December 2019 in Ouagadougou (Burkina Faso). All patients seen in rheumatology consultation in the city of Ouagadougou were included. The diagnosis of mechanical and degenerative osteoarthropathies was based on clinical and radiological findings; osteoarticular infection was based on clinical and biological findings. The diagnosis of gout was based on the clinical findings, uricemia, and/or the presence of sodium urate crystals in the synovial fluid on microscope. The diagnosis of rheumatoid arthritis and systemic lupus erythematosus was based on the ACR/EULAR criteria.

RESULTS

In total, 23,550 patients were included in the study. These were 14,995 female patients (63.70%) and 2555 male patients (36.30%). The average age of patients was 49.61 ± 15.36 years with extremes of 9 months to 120 years. Degenerative osteoarthropathies were the most common presentation (13,377 patients; 59.35%) followed by tendinopathies (2199 patients; 9.34%); chronic inflammatory rheumatism was in third place (841 patients; 3.57%) led by rheumatoid arthritis (434 patients); 51.61% of chronic inflammatory rheumatism, systemic lupus erythematosus and ankylosing spondylitis accounted for 71 patients (0.4%) and 63 patients (0.27%), respectively.

CONCLUSION

The epidemiology of rheumatic conditions is characterized by its diversity in hospital setting. The scarcity of some conditions such as systemic lupus erythematosus, psoriatic arthritis, and ankylosing spondylitis has been confirmed in this cohort. Key Points • Twenty-three thousand five hundred and fifty patients were included in the study • Rheumatoid arthritis was the most frequent (51.61%) chronic inflammatory rheumatism • Contrary to studies from Europe and America, systemic lupus seems rare in our series.

Natural Antioxidants as Additional Weapons in the Fight against Malarial Parasite

BACKGROUND

All currently available antimalarial drugs are developed from natural product lineages that may be traced back to herbal medicines, including quinine, lapachol, and artemisinin. Natural products that primarily target free radicals or reactive oxygen species, play an important role in treating malaria.

OBJECTIVES

This review analyses the role of antioxidative therapy in treating malaria by scavenging or countering free radicals and reviews the importance of natural plant extracts as antioxidants in oxidative therapy of malaria treatment.

METHODS

The search for natural antioxidants was conducted using the following databases: ResearchGate, ScienceDirect, Google Scholar, and Bentham Science with the keywords malaria, reactive oxygen species, natural antioxidants, and antiplasmodial.

CONCLUSION

This study reviewed various literature sources related to natural products employed in antimalarial therapy directly or indirectly by countering/scavenging reactive oxygen species published between 2016 till date. The literature survey made it possible to summarize the natural products used in treating malaria, emphasizing botanical extracts as a single component and in association with other botanical extracts. Natural antioxidants like polyphenols, flavonoids, and alkaloids, have a broad range of biological effects against malaria. This review is pivoted around natural antioxidants obtained from food and medicinal plants and explores their application in restraining reactive oxygen species (ROS). We anticipate this article will provide information for future research on the role of antioxidant therapy in malaria infection.

Non-lethal rodent malarial infection prevents collagen-induced arthritis in mice via anti-arthritic immunomodulation

AIMS

Immunomodulatory effects of parasitic infections on the outcomes of allergic or autoimmune disorders have been addressed in many experimental studies. We examined the effects of Plasmodium yoelii 17X NL (Py) infection on collagen-induced arthritis (CIA).

METHODS AND RESULTS

Male DBA/1J mice were immunized with bovine type II collagen (IIC). Py inoculation was induced at three different time points (1, 4 weeks after or 4 weeks before the immunization). Only the inoculation at 4 weeks after IIC immunization significantly inhibited arthritis development. Non-malarial anaemia induced by phenylhydrazine hydrochloride (PHZ) did not affect arthritis development. In the infected mice, anti-IIC IgG levels were transiently reduced. In addition, splenic production of pro-arthritic cytokines (IL-17 and TNF-α) and IFN-γ decreased, whereas IL-10 production increased. Flow cytometric analysis clarified that the main IL-10 producers in Py-infected mice had the CD4⁺ CD25^- Foxp3^- phenotype, presumably Tr1 cells.

CONCLUSION

We demonstrated that experimental malarial infection alleviated autoimmune arthritis via immunomodulation, suggesting the importance of malaria in the hygiene hypothesis and the significance of searching for therapeutic immunomodulatory molecules from malarial parasites.

Parasite-based interventions in systemic lupus erythematosus (SLE): A systematic review

BACKGROUND

The hygiene hypothesis proposed in 1989 expresses that allergic and infectious diseases are inversely related. Accordingly, it has been demonstrated that infection with some microorganisms such as parasites and helminths can provide a potential immunity and prevent the onset of some life-threatening autoimmune diseases like systemic lupus erythematosus (SLE). Therefore, in this comprehensive study, we systematically reviewed and discussed the use of live parasites or parasitic products in the treatment of mouse models of SLE.

METHODS

The present systematic review was performed using the following search terms: ("systemic lupus erythematosus" OR "SLE" OR "lupus") AND ("parasite" OR "protozoa" OR "helminths" OR "worms" OR "helminth" OR "worm") in PubMed, Scopus, and Web of Science online databases. We included studies reporting the effect of any intervention using parasites or parasitic-based products on animal models of SLE, which were published until January 20th, 2021 without any language or date restrictions. For each included study, we extracted the authors' names, publication year, type of animal, number of groups, types of intervention, sample size, changes in immunologic cells, auto-Abs, cytokines, and blood cells count, urine analysis, histological analysis of kidney/spleen/liver, outcome and survival. (PROSPERO CRD42020160460).

RESULTS

A total of 17 eligible articles were included in this systematic review. Sixteen out of the 17 studies reported immunomodulating changes in immunologic cells, cytokines, and/or auto-Abs in mouse models of SLE after using parasitic interventions compared to not-infected or control groups. Moreover, 14 studies reported decreased level of proteinuria and/or favorable kidney, liver, or spleen histological changes.

CONCLUSION

In conclusion, we have demonstrated that parasites like Hymenolepis microstoma, TPC and ES-62 from Acanthocheilonema viteae, Plasmodium chabaudi, Schistosoma mansoni, and Toxoplasma gondii have favorable immunomodulating effects on SLE outcomes in lupus-prone mice.

Current mechanistic insights into the role of infection in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by inflammation and abnormal production of autoantibody, but the mechanisms of the aberrant immune responses are currently unknown. Recently, growing evidence has suggested that infection plays a pivotal role in SLE. Here, we investigate the role of infectious agents (e.g., Epstein-Barr virus, parvovirus B19, human T-lymphotropic virus type 1, human immunodeficiency virus type 1, and endogenous retroviruses) in the pathogenesis of SLE. More importantly, we explore the known mechanisms underlying the involvement of infectious agents in the pathogenesis of SLE, including molecular mimicry, epitope spreading, superantigen production, bystander activation, persistent viral infection, altered apoptosis, clearance deficiency, and epigenetic alterations (e.g., DNA methylation and microRNAs). However, some infectious agents (e.g., malaria parasites, hepatitis B virus, Toxoplasma gondii, and Helicobacter pylori) may exert protective effects on SLE. Therefore, the relationship between infection and SLE is multifaceted and multidirectional, including causative and/or protective associations, which warrant further investigation in the future.

Altered renal immune complexes deposition in female BWF1 lupus mice following Plasmodium chabaudi infection

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that has a mysterious relationship with malaria infection. The current study was designated to compare between the effect of the live and the gamma irradiated Plasmodium chabaudi infection on BWF1 lupus murine model. A total of 30 female BWF1 mice were randomly divided into three groups (10 mice/group) as follows: group (I) lupus group (lupus non infected); group (II) live malaria infected group (lupus + live malaria infection); and group (III) irradiated malaria-infected group (lupus + gamma irradiated malaria infection). Live P. chabaudi infection was accompanied with a decrease in survival rate and food consumption in comparison to the control group of mice while gamma irradiated P. chabaudi -infection was unable to do this effect. Additionally, live P. chabaudi infection was accompanied with an increased level of proteinuria and increased rate of immune complexes deposition in kidney. Moreover, infection with live, but not gamma-irradiated P. chabaudi was accompanied with an increase in nitric oxide (NO), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) levels in plasma of lupus mice. The levels of both total cholesterol and triglycerides in plasma of lupus mice after live P. chabaudi infection were obviously decreased in comparison to the control group. On the other hand, gamma-irradiated P. chabaudi infection resembled the control group. Our data revealed that infection of lupus mice with live but not gamma-irradiated P. chabaudi has several histological and biochemical effects.

SLE: Another Autoimmune Disorder Influenced by Microbes and Diet?

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. Despite years of study, the etiology of SLE is still unclear. Both genetic and environmental factors have been implicated in the disease mechanisms. In the past decade, a growing body of evidence has indicated an important role of gut microbes in the development of autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. However, such knowledge on SLE is little, though we have already known that environmental factors can trigger the development of lupus. Several recent studies have suggested that alterations of the gut microbial composition may be correlated with SLE disease manifestations, while the exact roles of either symbiotic or pathogenic microbes in this disease remain to be explored. Elucidation of the roles of gut microbes - as well as the roles of diet that can modulate the composition of gut microbes - in SLE will shed light on how this autoimmune disorder develops, and provide opportunities for improved biomarkers of the disease and the potential to probe new therapies. In this review, we aim to compile the available evidence on the contributions of diet and gut microbes to SLE occurrence and pathogenesis.

Infection of Female BWF1 Lupus Mice with Malaria Parasite Attenuates B Cell Autoreactivity by Modulating the CXCL12/CXCR4 Axis and Its Downstream Signals PI3K/AKT, NFκB and ERK

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by abnormal autoreactivity in B cells. Lymphocytes and their soluble mediators contribute to the disease pathogenesis. We recently demonstrated that infecting lupus mice with malaria confers protection against lupus nephritis by attenuating oxidative stress in both liver and kidney tissues. In the current study, we further investigated B cell autoreactivity in female BWF1 lupus mice after infection with either live or gamma-irradiated malaria, using ELISA, flow cytometry and Western blot analysis. The lupus mice exhibited a significant elevation in plasma levels of IL-4, IL-6, IL-7, IL-12, IL-17, IFN-α, IFN-γ, TGF-β, BAFF and APRIL and a marked elevation of IgG2a, IgG3 and ant-dsDNA autoantibodies compared with normal healthy mice. Infecting lupus mice with live but not gamma-irradiated malaria parasite partially and significantly restored the levels of the soluble mediators that contribute to the progression of lupus. Furthermore, the B cells of lupus mice exhibited an increased proliferative capacity; aberrant overexpression of the chemokine receptor CXCR4; and a marked elevation in responsiveness to their cognate ligand (CXCL12) via aberrant activation of the PI3K/AKT, NFκB and ERK signaling pathways. Interestingly, infecting lupus mice with live but not gamma-irradiated malaria parasite restored a normal proliferative capacity, surface expression of CXCR4 and B cell response to CXCL-12. Taken together, our data present interesting findings that clarify, for the first time, the molecular mechanisms of how infection of lupus mice with malaria parasite controls B cell autoreactivity and thus confers protection against lupus severity.