Amelioration of colitis in mice by Leuconostoc lactis EJ‐1 by M1 to M2 macrophage polarization

Probiogenomics of Leuconostoc Mesenteroides Strains F-21 and F-22 Isolated from Human Breast Milk Reveal Beneficial Properties

Bacteria of the Leuconostoc genus are Gram-positive bacteria that are commonly found in raw milk and persist in fermented dairy products and plant food. Studies have already explored the probiotic potential of L. mesenteroides, but not from a probiogenomic perspective, which aims to explore the molecular features responsible for their phenotypes. In the present work, probiogenomic approaches were applied in strains F-21 and F-22 of L. mesenteroides isolated from human milk to assess their biosafety at the molecular level and to correlate molecular features with their potential probiotic characteristics. The complete genome of strain F-22 is 1.99 Mb and presents one plasmid, while the draft genome of strain F-21 is 1.89 Mb and presents four plasmids. A high percentage of average nucleotide identity among other genomes of L. mesenteroides (≥ 96%) corroborated the previous taxonomic classification of these isolates. Genomic regions that influence the probiotic properties were identified and annotated. Both strains exhibited wide genome plasticity, cell adhesion ability, proteolytic activity, proinflammatory and immunomodulation capacity through interaction with TLR-NF-κB and TLR-MAPK pathway components, and no antimicrobial resistance, denoting their potential to be candidate probiotics. Further, the strains showed bacteriocin production potential and the presence of acid, thermal, osmotic, and bile salt resistance genes, indicating their ability to survive under gastrointestinal stress. Taken together, our results suggest that L. mesenteroides F-21 and F-22 are promising candidates for probiotics in the food and pharmaceutical industries.

Unraveling the Protective Effect of Hesperetin In Experimentally Induced Colitis: Inhibition of NF-κB and NLRP3 Inflammasome Activation

This study aimed to investigate the protective effects of hesperetin (HES) against acetic acid (AA)-induced colitis (AAC) in rats through suppression of nuclear factor kappa B (NF-κB) and modulation of the NOD-like receptor pyrin-containing protein 3 (NLRP3) inflammasome. Forty-eight rats were allocated into four groups: control, AAC, HES-treated, and HES pre-treatment followed by AAC. Disease activity index (DAI), macroscopic and histological colonic changes were assessed. Moreover, inflammatory markers, and signaling pathways were evaluated through qRT-PCR, Western blot analysis, ELISA, and immunohistochemistry. HES pre-treatment significantly decreased the DAI by 61.31%, macroscopic colonic damage by 61.25% and the histological score by 41.86% compared to the AAC group. HES also reduced the expression of miR-155 by 73.79%, NLRP3 by 66.07%, Apoptosis-associated speck-like protein containing CARD (ASC) by 66.09%, cleaved caspase-1 by 63.86%, and the pyroptosis marker gasdermin-N (GSDMD-N) by 61.29%. Concurrently, HES attenuated the NF-κB pathway, reducing NF-κB-positive cells by 74.47% and p-inhibitory κB kinaseα (IκBα)/IκBα and p-Inhibitor of nuclear factor kappa-B kinase subunit alpha (IKKα/β)/IKKα/β levels by 43.77% and 38.68%, respectively. Inflammatory cytokines IL-1β and IL-18 were diminished by 73.41% and 71.88%, respectively. HES pre-treatment increased peroxisome proliferator-activated receptors-γ (PPAR-γ) expression by 259.97%, while reducing CD68+ macrophage infiltration by 72.72%. In conclusion, HES alleviated AAC in rats by targeting the NF-κB and NLRP3 inflammasome signaling pathways. This protective effect was mediated through the downregulation of miR-155 expression and the concurrent enhancement of PPAR-γ expression, resulting in reduced inflammation and pyroptosis. These findings highlight HES as a potential therapeutic protective agent for colitis.

The effect of intestinal flora metabolites on macrophage polarization

Intestinal flora metabolites played a crucial role in immunomodulation by influencing host immune responses through various pathways. Macrophages, as a type of innate immune cell, were essential in chemotaxis, phagocytosis, inflammatory responses, and microbial elimination. Different macrophage phenotypes had distinct biological functions, regulated by diverse factors and mechanisms. Advances in intestinal flora sequencing and metabolomics have enhanced understanding of how intestinal flora metabolites affect macrophage phenotypes and functions. These metabolites had varying effects on macrophage polarization and different mechanisms of influence. This study summarized the impact of gut microbiota metabolites on macrophage phenotype and function, along with the underlying mechanisms associated with different metabolites produced by intestinal flora.

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice

IMPORTANCE

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

Mechanistic insights into the role of probiotics in modulating immune cells in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a persistent inflammatory disorder that affects the gastrointestinal tract, mainly the colon, which is defined by inflammatory responses and the formation of ulcers. Probiotics have been shown to directly impact various immune cells, including dendritic cells (DCs), macrophages, natural killer (NK) cells, and T and B cells. By interacting with cell surface receptors, they regulate immune cell activity, produce metabolites that influence immune responses, and control the release of cytokines and chemokines.

METHODS

This article is a comprehensive review wherein we conducted an exhaustive search across published literature, utilizing reputable databases like PubMed and Web of Science. Our focus centered on pertinent keywords, such as "UC," 'DSS," "TNBS," "immune cells," and "inflammatory cytokines," to compile the most current insights regarding the therapeutic potential of probiotics in managing UC.

RESULTS

This overview aims to provide readers with a comprehensive understanding of the effects of probiotics on immune cells in relation to UC. Probiotics have a crucial role in promoting the proliferation of regulatory T cells (Tregs), which are necessary for preserving immunological homeostasis and regulating inflammatory responses. They also decrease the activation of pro-inflammatory cells like T helper 1 (Th1) and Th17 cells, contributing to UC development. Thus, probiotics significantly impact both direct and indirect pathways of immune cell regulation in UC, promoting Treg differentiation, inhibiting pro-inflammatory cell activation, and regulating cytokine and chemokine release.

CONCLUSION

Probiotics demonstrate significant potential in modulating the immune reactions in UC. Their capacity to modulate different immune cells and inflammation-related processes makes them a promising therapeutic approach for managing UC. However, further studies are warranted to optimize their use and fully elucidate the molecular mechanisms underlying their beneficial effects in UC treatment.

Lactic Acid Bacteria Isolated from Human Breast Milk Improve Colitis Induced by 2,4,6-Trinitrobenzene Sulfonic Acid by Inhibiting NF-κB Signaling in Mice

Inflammatory bowel disease (IBD), a chronic inflammatory disease, results from dysregulation of the immune responses. Some lactic acid bacteria (LAB), including Lactobacillus, alleviate IBD through immunomodulation. In this study, the anti-colitis effect of LAB isolated from human breast milk was investigated in a mouse model induced acute colitis with 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS remarkably increased weight loss, colon shortening, and colonic mucosal proliferation, as well as the expression levels of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β. Oral administration of LAB isolated from human breast milk resulted in a reduction in TNBS-induced colon shortening, as well as induced cyclooxygenase (COX)-2, nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB). In addition, LAB suppressed inflammatory cytokines such as TNF-α, IL-6, and IL-1β, and thus showed an effect of suppressing the level of inflammation induced by TNBS. Furthermore, LAB alleviated gut microbiota dysbiosis, and inhibited intestinal permeability by increasing the expression of intestinal tight junction protein including ZO-1. Collectively, these results suggest that LAB isolated from human breast milk can be used as a functional food for colitis treatment by regulating NF-κB signaling, gut microbiota and increasing expression of intestinal tight junction protein.

Inflammation, Autoinflammation and Autoimmunity in Inflammatory Bowel Diseases

In this review, the role of innate and adaptive immunity in the pathogenesis of inflammatory bowel diseases (IBD) is reported. In IBD, an altered innate immunity is often found, with increased Th17 and decreased Treg cells infiltrating the intestinal mucosa. An associated increase in inflammatory cytokines, such as IL-1 and TNF-α, and a decrease in anti-inflammatory cytokines, such as IL-10, concur in favoring the persistent inflammation of the gut mucosa. Autoinflammation is highlighted with insights in the role of inflammasomes, which activation by exogenous or endogenous triggers might be favored by mutations of NOD and NLRP proteins. Autoimmunity mechanisms also take place in IBD pathogenesis and in this context of a persistent immune stimulation by bacterial antigens and antigens derived from intestinal cells degradation, the adaptive immune response takes place and results in antibodies and autoantibodies production, a frequent finding in these diseases. Inflammation, autoinflammation and autoimmunity concur in altering the mucus layer and enhancing intestinal permeability, which sustains the vicious cycle of further mucosal inflammation.

Research progress on natural β-glucan in intestinal diseases

β-Glucan, an essential natural polysaccharide widely distributed in cereals and microorganisms, exhibits extensive biological activities, including immunoregulation, anti-inflammatory, antioxidant, antitumor properties, and flora regulation. Recently, increasing evidence has shown that β-glucan has activities that may be useful for treating intestinal diseases, such as inflammatory bowel disease (IBD), and colorectal cancer. The advantages of β-glucan, which include its multiple roles, safety, abundant sources, good encapsulation capacity, economic development costs, and clinical evidence, indicate that β-glucan is a promising polysaccharide that could be developed as a health product or medicine for the treatment of intestinal disease. Unfortunately, few reports have summarized the progress of studies investigating natural β-glucan in intestinal diseases. This review comprehensively summarizes the structure-activity relationship of β-glucan, its pharmacological mechanism in IBD and colorectal cancer, its absorption and transportation mechanisms, and its application in food, medicine, and drug delivery, which will be beneficial to further understand the role of β-glucan in intestinal diseases.

Lactobacillus plantarum synergistically regulates M1 macrophage polarization in resistance against Salmonella enterica serovar Typhimurium infection

Macrophage polarization affects the progression of pathogenic bacterial infections. Lactobacillus is widely used to interact with macrophages and to exert specific immunomodulatory activities. In this study, we investigated the regulation of macrophage polarization against Salmonella enterica serotype Typhimurium (STM) by Lactobacillus plantarum JL01 (LP), to explore prevention and treatment strategies for salmonellosis. We assessed the in vitro differential polarization of RAW 264.7 macrophages and mouse bone marrow macrophages (BMMs) by LP against STM, by measuring protein and cytokine levels, and bactericidal activity. In addition, we assessed the protective effects of LP against STM by evaluating weight loss, survival, the burden of STM in tissues, the polarization of macrophages in the spleen and mesenteric lymph nodes (MLNs), intestinal histopathology, and cytokine production. LP slightly affected the polarization of RAW 264.7, a slight M1-skewing. LP promoted the RAW 264.7 bactericidal activity against STM. In BMMs, M1 polarization induced by LP was significantly lower than the M1-positive phenotype. The combination of LP with M1 synergistically improved M1 polarization and bactericidal activity against STM compared to the individual effects. LP promoted the activation of the NF-κB signaling pathway. Supplementation with the NF-κB inhibitor decreased M1 polarization induced by LP. We observed the protective effect of LP against STM in C57BL/6 mice, through a decrease in weight loss, mortality, STM burden in the liver, and promotion of macrophage M1 and M2 polarization in the spleen and MLNs; though M1 was higher, it did not cause inflammatory damage. In summary, LP can synergistically promote M1 polarization in combination with the M1 phenotype through the NF-κB signaling pathway and increases resistance against S. Typhimurium infection. These findings will lay the foundation for the prevention and treatment of S. Typhimurium infections in the future.

The combination of sodium alginate and chlorogenic acid enhances the therapeutic effect on ulcerative colitis by the regulation of inflammation and the intestinal flora

Chlorogenic acid (CA) and sodium alginate (SA) each have good therapeutic effects on ulcerative colitis (UC) owing to their antioxidant and anti-inflammatory activity. This study aimed to investigate the effects of CA alone and in combination with SA on inflammatory cells and UC mice. In the Lipopolysaccharide (LPS)-induced RAW 264.7 inflammatory cell model, Nitric oxide (NO) and interleukin-6 (IL-6) levels were significantly lower after treatment with CA plus SA than with CA alone. In the DSS-induced UC mouse model, compared with CA alone, CA plus SA showed a better ability to alleviate weight loss, reduce the disease activity index (DAI), improve the colonic mucosa, reduce the expression of inflammatory factors in the serum and myeloperoxidase (MPO) in colonic tissue, increase superoxide dismutase (SOD) levels, protect the intestinal mucosa and regulate the abundance of Actinobacteriota, Lactobacillus, Bifidobacterium, Bacteroides, Subdoligranulum and Streptococcus. Thus, CA plus SA can improve the therapeutic efficacy of CA in UC by regulating inflammatory factors, oxidative stress, and the intestinal flora and by protecting ulcerative wounds. These findings broaden our understanding of the role of the combination of SA and CA in enhancing the effects of CA on UC and provide strategies for prevention and treatment.

Anti-arthritis effect of berberine associated with regulating energy metabolism of macrophages through AMPK/ HIF-1α pathway

Berberine (BBR) is the effective constituent of Cortex phellodendri and was characterized as an excellent anti-microbial agent with significant anti-inflammatory effects. Previously, we had demonstrated that BBR alleviated the inflammatory response in adjuvant-induced arthritis (AA) rats by regulating polarization of macrophages. However, the exact mechanics by which BBR regulates macrophage polarization remained unclear. Here, we showed that BBR treatment had little influence on total number of macrophages in joints of AA rats, but increased the proportion of M2 macrophages and decreased the proportion of M1 macrophages. Meanwhile, we found BBR up-regulated the expression of AMP-activated protein kinase phosphorylation (p-AMPK) and down-regulated the expression of Hypoxia inducible factor 1α (HIF-1α) in synovial macrophages of AA rats. In vitro, using LPS-stimulated peritoneal macrophages from normal rats, we also verified that pretreatment with BBR promoted transition from M1 to M2 by up-regulating the expression of p-AMPK and suppressing the expression of HIF-1α. Compound C (an AMPK inhibitor) could abrogate the inhibition of BBR on migration of macrophages. Glycolysis of M1 suppressed by BBR through decreasing lactate export, glucose consumption, and increasing intracellular ATP content, which was remarkably reversed by Compound C. These findings indicated that anti-arthritis effect of BBR is associated with regulating energy metabolism of macrophages through AMPK/HIF-1α pathway.

Development and application of an antibody that binds to interleukin-1β of various mammalian species for the treatment of inflammatory diseases

Inflammation is provoked by host immune reactions to pathogenic or tissue injury and is arbitrated by cytokines. Among the pro-inflammatory cytokines, the tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) are main mediators of inflammation. The production of these pro-inflammatory cytokines is mainly triggered in macrophages by harmful stimuli including microbial pathogens, irritants, and toxic cellular components, and plays key roles in the palpation of the inflammatory response. Among the therapeutic antibodies for the treatment of inflammation, those targeting TNF-α (including adalimumab and infliximab) are frequently used in clinical settings. Although IL-1β is a key cytokine for the onset of inflammatory diseases, such as inflammatory bowel disease (IBD) and type 2 diabetes (T2DM), few therapeutic antibodies exist for this cytokine, with the exception of canakinumab. Canakinumab binds to human IL-1β, but does not bind to murine IL-1β, which hampers its experimental use. Therefore, inflammation-therapeutic antibodies that bind to IL-1β of various mammals are needed. In this study, we report the development of an antibody that bound to IL-1β of various mammalian species and exhibited therapeutic effects in inflammatory diseases.