NOD1/2 and the C-Type Lectin Receptors Dectin-1 and Mincle Synergistically Enhance Proinflammatory Reactions Both In Vitro and In Vivo

Effects of a β-Glucan-Rich Blend of Medicinal Mushrooms and Botanicals on Innate Immune Cell Activation and Function Are Enhanced by a Very Low Dose of Bovine Colostrum Peptides

Nutraceutical immune support offers potential for designing blends with complementary mechanisms of action for robust support of innate immune alertness. We documented enhanced immune activation when bovine colostrum peptides (BC-Pep) were added to an immune blend (IB) containing β-glucans from yeast, shiitake, maitake, and botanical non-β-glucan polysaccharides. Human peripheral blood mononuclear cells (PBMCs) were cultured with IB, BC-Pep, and IB + BC-Pep for 20 h, whereafter expression of the activation marker CD69 was evaluated on NK cells, NKT cells, and T cells. Cytokine levels were tested in culture supernatants. PBMCs were co-cultured with K562 target cells to evaluate T cell-mediated cytotoxicity. IB + BC-Pep triggered highly significant increases in IL-1β, IL-6, and TNF-α, above that of cultures treated with matching doses of either IB or BC-Pep. NK cell and T cell activation was increased by IB + BC-Pep, reaching levels of CD69 expression several fold higher than either BC-Pep or IB alone. IB + BC-Pep significantly increased T cell-mediated cytotoxic killing of K562 target cells. This synergistic effect suggests unique amplification of signal transduction of NK cells and T cells due to modulation of IB-induced signaling pathways by BC-Pep and is of interest for further pre-clinical and clinical testing of immune defense activity against virally infected and transformed cells.

Chimeric NOD2 Mincle Agonists as Vaccine Adjuvants

There is a need for improved vaccine adjuvants to augment vaccine efficacy. One way to address this is by targeting multiple immune cell pathogen recognition receptors (PRRs) using chimeric pathogen-associated molecular patterns (PAMPs). Conjugation of the PAMPs will ensure codelivery of the immunostimulatory molecules to the same cell, enhancing adjuvant activity. The macrophage inducible C-type lectin (Mincle) is a promising PRR for adjuvant development; however, no effective chimeric Mincle adjuvants have been prepared. We addressed this by synthesizing Mincle adjuvant conjugates, MDP-C18Brar and MDP-C18Brar-dilipid, which contain PAMPs recognized by Mincle and the nucleotide-binding oligomerization domain 2 (NOD2). The two PAMPs are joined by a pH-sensitive oxyamine linker which, upon acidification at lysosomal pH, hydrolyzed to release the NOD2 ligands. The conjugates elicited the production of Th1 and Th17 promoting cytokines in vitro, and when using OVA as a model antigen, exhibited enhanced T-cell-mediated immune responses and reduced toxicity in vivo, compared to the coadministration of the adjuvants.

Chemotherapeutic Drugs Induce Different Gut Microbiota Disorder Pattern and NOD/RIP2/NF-κB Signaling Pathway Activation That Lead to Different Degrees of Intestinal Injury

5-Fluorouracil (5-FU), irinotecan (CPT-11), oxaliplatin (L-OHP), and calcium folinate (CF) are widely used chemotherapeutic drugs to treat colorectal cancer. However, chemotherapeutic use is often accompanied by intestinal inflammation and gut microbiota disorder. Changes in gut microbiota may destroy the intestinal barrier, which contributes to the severity of intestinal injury. However, intestinal injury and gut microbiota disorder have yet to be compared among 5-FU, CPT-11, L-OHP, and CF in detail, thereby limiting the development of targeted detoxification therapy after chemotherapy. In this study, a model of chemotherapy-induced intestinal injury in tumor-bearing mice was established by intraperitoneally injecting chemotherapeutic drugs at a clinically equivalent dose. 16S rRNA gene sequencing was used to detect gut microbiota. We found that 5-FU, CPT-11, and l-OHP caused intestinal injury, inflammatory cytokine (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], interleukin-1β [IL-1β], and IL-6) secretion, and gut microbiota disorder. We established a complex but clear network between the pattern of changes in gut microbiota and degree of intestinal damage induced by different chemotherapeutic drugs. L-OHP caused the most severe damage in the intestine and disorder of the gut microbiota and showed a considerable overlap of the pattern of changes in microbiota with 5-FU and CPT-11. Analysis by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt v.1.0) showed that the microbiota disorder pattern induced by 5-FU, CPT-11, and L-OHP was related to the NOD-like signaling pathway. Therefore, we detected the protein expression of the NOD/RIP2/NF-κB signaling pathway and found that L-OHP most activated this pathway. Redundancy analysis/canonical correlation analysis (RDA/CCA) revealed that Bifidobacterium, Akkermansia, Allobaculum, Catenibacterium, Mucispirillum, Turicibacter, Helicobacter, Proteus, Escherichia Shigella, Alloprevotealla, Vagococcus, Streptococcus, and "Candidatus Saccharimonas" were highly correlated with the NOD/RIP2/NF-κB signaling pathway and influenced by chemotherapeutic drugs. IMPORTANCE Chemotherapy-induced intestinal injury limits the clinical use of drugs. Intestinal injury involves multiple signaling pathways and gut microbiota disruption. Our results suggested that the degree of intestinal injury caused by different drugs of the first-line colorectal chemotherapy regimen is related to the pattern of changes in microbiota. The activation of the NOD/RIP2/NF-κB signaling pathway was also related to the pattern of changes in microbiota. l-OHP caused the most severe damage to the intestine and showed a considerable overlap of the pattern of changes in microbiota with 5-FU and CPT-11. Thirteen bacterial genera were related to different levels of intestinal injury and correlated with the NOD/RIP2/NF-κB pathway. Here, we established a network of different chemotherapeutic drugs, gut microbiota, and the NOD/RIP2/NF-κB signaling pathway. This study likely provided a new basis for further elucidating the mechanism and clinical treatment of intestinal injury caused by chemotherapy.