How major fungal infections can initiate severe autoimmune diseases

Preeclampsia and eclampsia: the role of hemolytic protozoan iron

Organisms as well as pathogens require several transition metals including iron, copper, zinc, manganese, nickel and cobalt, for genetic replication and other cellular functions. Of these, iron is vital and plays a key role in DNA replication, transcription, synthesis of cofactors and other essential enzymes. During infection, iron deprivation, particularly sequestration thereof, represents a unique response against pathogen attack. The host sequesters ferrous (Fe2+) and ferric (Fe3+) iron via lactoferrin binding at mucosal surfaces, transferrin in blood and tissue and ferritin in blood and cytoplasm. Despite this protective mechanism, pathogens can be resilient in obtaining iron. For example, hemolytic protozoan parasites can obtain iron from heme by rupturing red blood cells. Furthermore, earlier pathogens, driven from active to inactive infections by iron deprivation, could now acquire sufficient iron to enable reactivation resulting in chronic inflammation, oxidative stress to organs and/or circulatory hypertension potentially leading to death. This review discusses the impact of hemolytic protozoan parasite infection in reactivation of latent iron-deprived pathogen infections thus explaining two puzzling pregnancy disorders, pre-eclampsia (PE) and eclampsia. The unknown causations of both disorders have created centuries of confusion and killed millions of women worldwide. Furthermore, reduction-oxidation reactions with iron promote additional oxidative stress damage to vital organs, particularly the kidneys, a common symptom in PE and eclampsia.

Fish Oil Ameliorates Vibrio parahaemolyticus Infection in Mice by Restoring Colonic Microbiota, Metabolic Profiles, and Immune Homeostasis

The effect of fish oil (FO) on colonic function, immunity, and microbiota was investigated in Vibrio parahaemolyticus (Vp)-infected C57BL/6J mice. Mice intragastrically presupplemented with FO (4.0 mg) significantly reduced Vp infection as evidenced by stabilizing body weight and reducing disease activity index score and immune organ ratios. FO minimized colonic pathological damage, strengthened the mucosal barrier, and sustained epithelial permeability by increasing epithelial crypt depth, goblet cell numbers, and tight junctions and inhibiting colonic collagen accumulation and fibrosis protein expression. Mechanistically, FO enhanced immunity by decreasing colonic CD³⁺ T cells, increasing CD⁴⁺ T cells, downregulating the TLR4 pathway, reducing interleukin-17 (IL-17) and tumor necrosis factor-α, and increasing immune cytokine IL-4 and interferon-γ levels. Additionally, FO maintained colonic microbiota eubiosis by improving microbial diversity and boosting Clostridium, Akkermansia, and Roseburia growth and their derived propionic acid and butyric acid levels. Collectively, FO alleviated Vp infection by enriching beneficial colonic microbiota and metabolites and restoring immune homeostasis.

Systemic Infection by Non-albicans Candida Species Affects the Development of a Murine Model of Multiple Sclerosis

Candidiasis may affect the central nervous system (CNS), and although Candida albicans is predominant, non-albicans Candida species can also be associated with CNS infections. Some studies have suggested that Candida infections could increase the odds of multiple sclerosis (MS) development. In this context, we investigated whether systemic infection by non-albicans Candida species would affect, clinically or immunologically, the severity of experimental autoimmune encephalomyelitis (EAE), which is an animal model used to study MS. For this, a strain of C. glabrata, C. krusei, and C. parapsilosis was selected and characterized using different in vitro and in vivo models. In these analysis, all the strains exhibited the ability to form biofilms, produce proteolytic enzymes, and cause systemic infections in Galleria mellonella, with C. glabrata being the most virulent species. Next, C57BL/6 mice were infected with strains of C. glabrata, C. krusei, or C. parapsilosis, and 3 days later were immunized with myelin oligodendrocyte glycoprotein to develop EAE. Mice from EAE groups previously infected with C. glabrata and C. krusei developed more severe and more prevalent paralysis, while mice from the EAE group infected with C. parapsilosis developed a disease comparable to non-infected EAE mice. Disease aggravation by C. glabrata and C. krusei strains was concomitant to increased IL-17 and IFN-γ production by splenic cells stimulated with fungi-derived antigens and with increased percentage of T lymphocytes and myeloid cells in the CNS. Analysis of interaction with BV-2 microglial cell line also revealed differences among these strains, in which C. krusei was the strongest activator of microglia concerning the expression of MHC II and CD40 and pro-inflammatory cytokine production. Altogether, these results indicated that the three non-albicans Candida strains were similarly able to reach the CNS but distinct in terms of their effect over EAE development. Whereas C. glabrata and C. Krusei aggravated the development of EAE, C. parapsilosis did not affect its severity. Disease worsening was partially associated to virulence factors in C. glabrata and to a strong activation of microglia in C. krusei infection. In conclusion, systemic infections by non-albicans Candida strains exerted influence on the experimental autoimmune encephalomyelitis in both immunological and clinical aspects, emphasizing their possible relevance in MS development.

Autism Spectrum Disorder Initiation by Inflammation-Facilitated Neurotoxin Transport

Autism spectrum disorders have been linked to genetics, gut microbiota dysbiosis (gut dysbiosis), neurotoxin exposures, maternal allergies or autoimmune diseases. Two barriers to ingested neurotoxin transport into the central nervous system of a fetus or child are the gastrointestinal wall of the mother or child and the blood-brain barrier of the fetus or child. Inflammation from gut dysbiosis or inflammation from a disease or other agent can increase the gastrointestinal wall and the blood-brain barrier permeabilities to enable neurotoxins to reach the brain of a fetus or child. Postnatal gut dysbiosis is a particular inflammation risk for autism spectrum disorders caused by neurotoxin transport into a child's brain. An extensive gut dysbiosis or another source of inflammation such as a disease or other agent in combination with neurotoxins, including aluminum, mercury, lead, arsenic, cadmium, arsenic, organophosphates, and neurotoxic bacterial toxins and fungal toxins resulting from the gut dysbiosis, can elevate neurotoxin levels in a fetal or child brain to cause neurodevelopmental damage and initiate an autism spectrum disorder. The neurotoxins aluminum and mercury are especially synergistic in causing neurodevelopmental damage. There are three plausible causational pathways for autism spectrum disorders. They include inflammation and neurotoxin loading into the fetal brain during the prenatal neurodevelopment period, inflammation and neurotoxin loading into the brain during the postnatal neurodevelopment period or a two-stage loading of neurotoxins into the brain during both the prenatal and postnatal neurodevelopment periods.