Omeprazole inhibits IgE-mediated mast cell activation and allergic inflammation induced by ingested allergen in mice. Kanagaratham Cynthia,El Ansari Yasmeen S,Sallis Benjamin F,Hollister Brianna-Marie A,Lewis Owen L,Minnicozzi Samantha C,Oyoshi Michiko K,Rosen Rachel,Nurko Samuel,Fiebiger Edda,Oettgen Hans C The Journal of allergy and clinical immunology BACKGROUND:Patients with eosinophilic esophagitis have increased numbers of mucosal mast cells. Administration of the proton pump inhibitor omeprazole can reduce both esophageal mast cell and eosinophil numbers and attenuate type 2 inflammation in these subjects. OBJECTIVE:Given that maintenance of an acidic environment within granules is important for mast cell homeostasis, we sought to evaluate the effects of omeprazole on mast cell functions including development, IgE:FcεRI-mediated activation, and responses to food allergen. METHODS:Mast cell degranulation, cytokine secretion, and early signaling events in the FcεRI pathway, including protein kinase phosphorylation and Ca flux, were measured after IgE crosslinking in murine bone marrow-derived mast cells and human cord blood-derived mast cells. The effects of omeprazole on these responses were investigated as was its impact on mast cell-dependent anaphylaxis and food allergy phenotypes in vivo. RESULTS:Murine and human mast cells treated with omeprazole exhibited diminished degranulation and release of cytokines and histamine in response to allergen. In murine mast cells, phosphorylation of protein kinases, ERK and SYK, was decreased. Differentiation of mast cells from bone marrow progenitors was also inhibited. IgE-mediated passive anaphylaxis was blunted in mice treated with omeprazole as was allergen-induced mast cell expansion and mast cell activation in the intestine in a model of food allergy. CONCLUSIONS:Our findings suggest that omeprazole targets pathways important for the differentiation and activation of murine mast cells and for the manifestations of food allergy and anaphylaxis. 10.1016/j.jaci.2020.02.032

Inhibitory effects of orientin in mast cell-mediated allergic inflammation. Dhakal Hima,Lee Soyoung,Choi Jin Kyeong,Kwon Taeg Kyu,Khang Dongwoo,Kim Sang-Hyun Pharmacological reports : PR BACKGROUND:Mast cells are immune effector cells mediating allergic inflammation by the secretion of inflammatory mediators such as histamine and pro-inflammatory cytokines. Orientin is a naturally occurring bioactive flavonoid that possesses diverse biological properties, including anti-inflammation, anti-oxidative, anti-tumor, and cardio protection. The objective of this study was to rule out the effectiveness of orientin in mast cell-mediated allergic inflammation. METHODS:In this study, in vitro effects of orientin were evaluated in RBL-2H3, mouse bone marrow-derived mast cells, rat peritoneal mast cells, and in vivo effects were evaluated by inducing passive cutaneous anaphylaxis (PCA) in Imprinting Control Region (ICR) mice. RESULTS:Findings show that orientin suppressed the immunoglobulin E (IgE)-mediated mast cell degranulation by reducing intracellular calcium level in a concentration-dependent manner. Orientin suppressed the secretion of pro-inflammatory cytokines in mast cells. This inhibitory effects of orientin was through inhibition of FcεRI-mediated signaling proteins. In addition, oral administration of orientin suppressed the IgE-mediated PCA reactions in a dose-dependent manner, which was evidenced by reduced Evan's blue pigmentation and ear swelling. CONCLUSIONS:Based on these findings, we suggest that orientin might have potential to alleviate allergic reaction and mast cell-mediated allergic disease. 10.1007/s43440-019-00048-3

S-layer protein 2 of Lactobacillus crispatus 2029, its structural and immunomodulatory characteristics and roles in protective potential of the whole bacteria against foodborne pathogens. Abramov Vyacheslav M,Kosarev Igor V,Priputnevich Tatiana V,Machulin Andrey V,Khlebnikov Valentin S,Pchelintsev Sergey Yu,Vasilenko Raisa N,Sakulin Vadim K,Suzina Natalia E,Chikileva Irina O,Derysheva Evgenia I,Melnikov Vyacheslav G,Nikonov Ilya N,Samoilenko Vladimir A,Svetoch Eduard E,Sukhikh Gennady T,Uversky Vladimir N,Karlyshev Andrey V International journal of biological macromolecules We have previously demonstrated that human vaginal Lactobacillus crispatus 2029 (LC2029) strain is highly adhesive to cervicovaginal epithelial cells, exhibits antagonistic activity against genitourinary pathogens and expresses surface-layer protein (Slp). The aims of the present study were elucidation of Slp structural and immunomodulatory characteristics and its roles in protective properties of the whole vaginal LC2029 bacteria against foodborne pathogens. Enteric Caco-2 and colon HT-29 cell lines were used as the in vitro models of the human intestinal epithelial layer. LC2029 strain has two homologous surface-layer (S-layer) genes, slp1 and slp2. Whilst we found no evidence for the expression of slp1 under the growth conditions used, a very high level of expression of the slp2 gene was detected. C-terminal part of the amino sequence of Slp2 protein was found to be highly similar to that of the conserved C-terminal region of SlpA protein of L. crispatus Zj001 isolated from pig intestines and CbsA protein of L. crispatus JCM5810 isolated from chicken intestines, and was substantially variable at the N-terminal and middle regions. The amino acid sequence identity between SlpA and CbsA was as high as 84%, whilst the identity levels of these sequences with that of Slp2 were only 49% and 50% (respectively). LC2029 strain was found to be both acid and bile tolerant. Survival in simulated gastric and intestinal juices of LC2029 cells unable to produce Slp2 was reduced by 2-3 logs. Vaginal L. crispatus 1385 (LC1385) strain not expressing Slp was also very sensitive to gastric and intestinal stresses. Slp2 was found to be non-covalently bound to the surface of the bacterium, acting as an adhesin and facilitating interaction of LC2029 lactobacilli with the host immature or fully differentiated Caco-2 cells, as well as HT-29 cells. No toxicity to or damage of Caco-2 or HT-29 epithelial cells were detected after 24 h of colonization by LC2029 lactobacilli. Both Slp2 protein and LC2029 cells induced NF-kB activation in Caco-2 and HT-29 cells, but did not induce expression of innate immunity mediators Il-8, Il-1β, and TNF-α. Slp2 and LC2029 inhibited Il-8 production in Caco-2 and HT-29 cells induced by MALP-2 and increased production of anti-inflammatory cytokine Il-6. Slp2 inhibited production of CXCL1 and RANTES by Caco-2 cells during differentiation and maturation process within 15 days. Culturing Caco-2 and HT-29 cells in the presence of Slp2 increased adhesion of bifidobacteria BLI-2780 to these enterocytes. Upon binding to Caco-2 and HT-29 cells, Slp2 protein and LC2029 lactobacilli were recognized by toll-like receptors (TLR) 2/6. It was shown that LC2029 strain is a strong co-aggregator of foodborne pathogens Campylobacter jejuni, Salmonella enteritidis, and Escherichia coli O157:H used in this study. The Slp2 was responsible for the ability of LC2029 to co-aggregate these enteropathogens. Slp2 and intact LC2029 lactobacilli inhibited foodborne pathogen-induced activation of caspase-9 and caspase-3 as apoptotic biomarkers in Caco-2 and HT-29 cells. In addition, Slp2 and Slp2-positive LC2029 strain reduced adhesion of tested pathogenic bacteria to Caco-2 and HT-29 cells. Slp2-positive LC2029 strain but not Slp2 alone provided bactericidal effect on foodborne pathogens. These results suggest a range of mechanisms involved in inhibition of growth, viability, and cell-adhesion properties of pathogenic Proteobacteria by the Slp2 producing LC2029, which may be useful in treatment of necrotizing enterocolitis (NEC) in newborns and foodborne infectious diseases in children and adults, increasing the colonization resistance and maintaining the intestinal homeostasis. 10.1016/j.ijbiomac.2020.02.065

The S-layer proteins of Lactobacillus crispatus strain ZJ001 is responsible for competitive exclusion against Escherichia coli O157:H7 and Salmonella typhimurium. Chen Xueyan,Xu Jingjing,Shuai Jiangbing,Chen Jianshun,Zhang Zhanfeng,Fang Weihuan International journal of food microbiology Lactobacillus crispatus ZJ001, isolated from pig intestines and identified by sequencing analysis based on partial 16S rRNA gene, was examined in vitro for probiotic activity exerted by the surface layer proteins (S-layer). The characteristics of L. crispatus ZJ001 were compared to Lactobacillus acidophilus ATCC 4356 from the same genus which also produces the S-layer proteins. The strain ZJ001 was resistant to acidic condition and bile salt. Its antagonistic properties such as adhesion, inhibition of the pathogen growth and competitive exclusion against Escherichia coli O157:H7 and Salmonella typhimurium were apparently advantageous over L. acidophilus ATCC 4356. SDS-PAGE analysis of cell surface proteins revealed the presence of S-layer proteins, approximately at 42 kDa in L. crispatus ZJ001. Removal of the S-layer proteins reduced autoaggregation and adhesion to HeLa cells. The functional role of the S-layer proteins in adhesion was also confirmed by the antibody-mediated inhibition assay using the polyclonal antibody against the S-layer protein. The S-layer proteins from L. crispatus ZJ001 inhibited adhesion of S. typhimurium and E. coli O157:H7 to HeLa cells. These results suggest that L. crispatus ZJ001 possesses probiotic properties and the S-layer proteins are involved in the adhesion and competitive exclusion of pathogens to HeLa cells. 10.1016/j.ijfoodmicro.2006.11.007