The modulation and mechanism of probiotic-derived polysaccharide capsules on the immune response in allergic diseases

Harnessing the polysaccharide production potential to optimize and expand the application of probiotics

Certain probiotic microorganisms can synthesize important bioproducts, including polysaccharides as components of cellular structure or extracellular matrix. Probiotic-derived polysaccharides have been widely applied in food, pharmaceutical, and medical fields due to their excellent properties and biological activities. The development of polysaccharide production potential has become a driving force for facilitating biotechnological applications of probiotics. Based on technical advances in synthetic biology, significant progress has recently been made in engineering probiotics with efficient biosynthesis of polysaccharides. Herein, this review summarizes probiotics chassis and genetic tools used for polysaccharide production. Then, probiotic polysaccharides and relevant biosynthesis mechanisms are also clearly described. Next, we introduce strategies for preparing high-yield, controllable molecular weight or non-native polysaccharides by adjusting metabolic pathways and integrating expression elements in probiotics. Finally, some prospective and well-established contributions of exogenous and in situ polysaccharides in probiotics' stability, bioactivity, and therapeutic effects are presented. Our viewpoints on advancing the efficient biomanufacturing of valuable biopolymers in probiotics and engineering probiotics with customized features are provided to exploit probiotics' industrial and biomedical applications.

Immunostimulatory activity of sea buckthorn polysaccharides via TLR2/4-mediated MAPK and NF-κB signaling pathways in vitro and in vivo

SP0.1-1, derived from Sea buckthorn (Hippophae rhamnoides L.), has been discovered to exhibit unique antioxidant activity. In this study, we investigated the immunomodulatory activity and mechanisms of SP0.1-1 on macrophage RAW 264.7 cells in vitro and immunosuppressive mice induced by cyclophosphamide in vivo. The results indicated SP0.1-1 strengthened the immune functions via promoting the proliferation of RAW264.7 cells and phagocytic activity, along with stimulating the release of NO, ROS and cytokines including TNF-α, IL-6, IL-1β and IFN-γ. Western blot and molecular docking analysis demonstrated that SP0.1-1 attached to the prime receptors TLR2 and TLR4 in RAW264.7 cells, and triggered the activation of MyD88-mediated MAPK and NF-κB signaling pathways, thereby exerting the immune response in RAW264.7 cells. However, the intervention of specific inhibitors against TLR2, TLR4, JNK, ERK, p38 and NF-κB blocked the TLR-mediated MAPK and NF-κB signaling pathways and downregulated the levels of NO and the aforementioned cytokines, thus suppressing the activation of macrophages. Therefore, it can be speculated that SP0.1-1 activated the macrophages principally via the TLR2/4-MyD88-mediated MAPK and NF-κB signaling pathways. Additionally, SP0.1-1 could protect against the cyclophosphamide-induced immunosuppression in mice, manifested by the improvement of body weight, immune organ indices, phagocytic index, and the relievement of spleen damage, along with the enhancement of cytokines TNF-α, IL-6, IFN-γ and immunoglobulin IgG and IgM. These findings will shed light on the molecular mechanism of SP0.1-1 on the immunoregulatory effect, and lay the foundation for exploiting a potential immunostimulatory agent of SP0.1-1.

The role of Th/Treg immune cells in osteoarthritis

Osteoarthritis (OA) is a prevalent clinical condition affecting the entire joint, characterized by its multifactorial etiology and complex pathophysiology. The onset of OA is linked to inflammatory mediators produced by the synovium, cartilage, and subchondral bone, all of which are closely tied to cartilage degradation. Consequently, OA may also be viewed as a systemic inflammatory disorder. Emerging studies have underscored the significance of T cells in the development of OA. Notably, imbalances in Th1/Th2 and Th17/Treg immune cells may play a crucial role in the pathogenesis of OA. This review aims to compile recent advancements in understanding the role of T cells and their Th/Treg subsets in OA, examines the immune alterations and contributions of Th/Treg cells to OA progression, and proposes novel directions for future research, including potential therapeutic strategies for OA.

Modulation of the Immune System Mechanisms using Probiotic Bacteria in Allergic Diseases: Focus on Allergic Retinitis and Food Allergies

Allergic illnesses occur when an organism's immune system is excessively responsive to certain antigens, such as those that are presented in the environment. Some people suffer from a wide range of immune system-related illnesses including allergic rhinitis, asthma, food allergies, hay fever, and even anaphylaxis. Immunotherapy and medications are frequently used to treat allergic disorders. The use of probiotics in bacteriotherapy has lately gained interest. Probiotics are essential to human health by modulating the gut microbiota in some ways. Due to probiotics' immunomodulatory properties present in the gut microbiota of all animals, including humans, these bacterial strains can prevent a wide variety of allergic disorders. Probiotic treatment helps allergy patients by decreasing inflammatory cytokines and enhancing intestinal permeability, which is important in the battle against allergy. By altering the balance of Th1 and Th2 immune responses in the intestinal mucosa, probiotics can heal allergic disorders. Numerous studies have shown a correlation between probiotics and a reduced risk of allergy disorders. A wide range of allergic disorders, including atopic dermatitis, asthma, allergic retinitis and food allergies has been proven to benefit from probiotic bacteria. Therefore, the use of probiotics in the treatment of allergic diseases offers a promising perspective. Considering that probiotic intervention in the treatment of diseases is a relatively new field of study, more studies in this regard seem necessary.

Structural characterization of polysaccharides recovered from extraction residue of ginseng root saponins and its fruit nutrition preservation performance

Polysaccharides recovered from extraction residue of ginseng root saponins, i.e., ginsenosides-extracting residue polysaccharides (GRP), were separated into two fractions, GRP-1 and GRP-2. Fourier infrared and nuclear magnetic resonance spectra, as well as high-performance liquid chromatography and gel permeation chromatography measurements, showed GRP-1 was composed of mainly starch-like glucans and GRP-2, relatively a smaller portion, was a mixture of heteropolysaccharides composed of starch-like glucans, rhamnogalacturonan-I pectin, and arabinogalactans, and they had similar molecular weights. These results proved that the structure of GRP was not destroyed and GRP still maintained strong antioxidant activities. In addition, GRP coating on surfaces of fruit slowed their deterioration and maintained their nutritional effects. Correlation and PCA analyses on various quality and antioxidant parameters supported the above findings and a possible mechanism in fruit preservation was then proposed. Knowing the structural features and bioactivities of GRP gives insights into its application. Specifically, GRP served as an environmentally friendly coating that can be used to preserve the nutrients and other quality indicators of strawberries and fresh-cut apples, paving the way for future new approaches to food preservation using polysaccharides or other natural products.