Dietary Chitin Particles Called Mimetic Fungi Ameliorate Colitis in Toll-Like Receptor 2/CD14- and Sex-Dependent Manners

Hyperactivation of human acidic chitinase (Chia) for potential medical use

Accumulation of environmental chitin in the lungs can lead to pulmonary fibrosis, characterized by inflammatory infiltration and fibrosis in acidic chitinase (Chia)-deficient mice. Transgenic expression of Chia in these mice ameliorated the symptoms, indicating the potential of enzyme supplementation as a promising therapeutic strategy for related lung diseases. This study focuses on utilizing hyperactivated human Chia, which exhibits low activity. We achieved significant activation of human Chia by incorporating nine amino acids derived from the crab-eating monkey (Macaca fascicularis) Chia, known for its robust chitin-degrading activity. The modified human Chia retained high activity across a broad pH spectrum and exhibited enhanced thermal stability. The amino acid substitutions associated with hyperactivation of human Chia activity occurred species specifically in monkey Chia. This discovery highlights the potential of hyperactivated Chia in treating pulmonary diseases resulting from chitin accumulation in human lungs.

How Gut Bacterial Dysbiosis Can Promote Candida albicans Overgrowth during Colonic Inflammation

Candida albicans is a commensal opportunistic yeast, which is capable of colonising many segments of the human digestive tract. Excessive C. albicans overgrowth in the gut is associated with multiple risk factors such as immunosuppression, antibiotic treatment associated with changes to the gut microbiota and digestive mucosa that support C. albicans translocation across the digestive intestinal barrier and haematogenous dissemination, leading to invasive fungal infections. The C. albicans cell wall contains mannoproteins, β-glucans, and chitin, which are known to trigger a wide range of host cell activities and to circulate in the blood during fungal infection. This review describes the role of C. albicans in colonic inflammation and how various receptors are involved in the immune defence against C. albicans with a special focus on the role of mannose-binding lectin (MBL) and TLRs in intestinal homeostasis and C. albicans sensing. This review highlights gut microbiota dysbiosis during colonic inflammation in a dextran sulphate sodium (DSS)-induced colitis murine model and the effect of fungal glycan fractions, in particular β-glucans and chitin, on the modification of the gut microbiota, as well as how these glycans modulate the immuno-inflammatory response of the host.

The important role of fungi in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a life-threatening and chronic inflammatory disease of gastrointestinal tissue, with complex pathogenesis. Current research on IBD has mainly focused on bacteria; however, the role of fungi in IBD is largely unknown due to the incomplete annotation of fungi in current genomic databases. With the development of molecular techniques, the gut mycobiome has been found to have great diversity. In addition, increasing evidence has shown intestinal mycobiome plays an important role in the physiological and pathological processes of IBD. In this review, we will systemically introduce the recent knowledge about multi-dimensional fungal dysbiosis associated with IBD, the interactions between fungus and bacteria, the role of fungi in inflammation in IBD, and highlight recent advances in the potential therapeutic role of fungus in IBD, which may hold the keys to develop new predictive, therapeutic or prognostic approaches in IBD.

Bioreactivity of decellularized animal, plant, and fungal scaffolds: perspectives for medical applications

Numerous biomedical applications imply supportive materials to improve protective, antibacterial, and regenerative abilities upon surgical interventions, oncotherapy, regenerative medicine, and others. With the increasing variability of the possible sources, the materials of natural origin are among the safest and most accessible biomedical tools. Animal, plant, and fungal tissues can further undergo decellularization to improve their biocompatibility. Decellularized scaffolds lack the most reactive cellular material, nuclear and cytoplasmic components, that predominantly trigger immune responses. At the same time, the outstanding initial three-dimensional microarchitecture, biomechanical properties, and general composition of the scaffolds are preserved. These unique features make the scaffolds perfect ready-to-use platforms for various biomedical applications, implying cell growth and functionalization. Decellularized materials can be repopulated with various cells upon request, including epithelial, endothelial, muscle and neuronal cells, and applied for structural and functional biorepair within diverse biological sites, including the skin and musculoskeletal, cardiovascular, and central nervous systems. However, the molecular and cellular mechanisms behind scaffold and host tissue interactions remain not fully understood, which significantly restricts their integration into clinical practice. In this review, we address the essential aspects of decellularization, scaffold preparation techniques, and its biochemical composition and properties, which determine the biocompatibility and immunogenicity of the materials. With the integrated evaluation of the scaffold profile in living systems, decellularized animal, plant, and fungal scaffolds have the potential to become essential instruments for safe and controllable biomedical applications.

Oral chitin treatment improved demyelination in murine autoimmune encephalomyelitis model by inhibition of inflammatory responses

This study aimed to determine whether chitin microparticles (CMP), glucosamine-based polymers, have an anti-inflammatory response in a murine model of autoimmune encephalomyelitis. Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice by immunization with myelin antigens emulsified in complete Freund adjuvant. A standard clinical and histological method (Luxol Fast Blue staining) was used to validate the model and document the impact of CMP treatment. ELISA was used to determine the production of spleen cell cytokines and serum levels of anti-chitin antibodies. Flowcytometry was used to determine the percentage of regulatory lymphocytes. The relative expression of the breast regression protein 39 (BRP-39) gene was examined through real time-PCR amplification. Clinical signs were significantly improved in mice given CMP compared with untreated mice. Histological analysis of the spinal cord revealed that treatment significantly reduced demyelination. The levels of interferon-γ, interleukin-17, and tumor necrosis factor-α were also reduced; conversely, no significant change was detected in interleukin-10 level and regulatory T cell count. The CMP-fed mice showed lower BRP-39 expression compared with the control group. It was ultimately determined that CMP modulates immune responses which could indirectly alter the pathology of an injured central nervous system. The data suggests that CMP may be used as an effective and cheap oral therapeutic agent for multiple sclerosis.