The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory ...The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.展开更多
Food allergy(FA) is an aberrant immune response triggered by the ingestion of a food antigen.Ovalbumin(OVA)-sensitized and challenged BALB/c mice were orally administered heat-killed(HK)-Lactobacillus paracasei JY56.I...Food allergy(FA) is an aberrant immune response triggered by the ingestion of a food antigen.Ovalbumin(OVA)-sensitized and challenged BALB/c mice were orally administered heat-killed(HK)-Lactobacillus paracasei JY56.In this work,HK-L.paracasei JY56 alleviated the FA-induced decrease in body weight and rectal temperature and reduced the allergy score.Serum analysis showed that HK-L.paracasei JY56 reduced the levels of specific antibodies(OVA-specific Immunoglobulin E(sIgE) and OVA-specific Immunoglobulin G(sIgG)) and allergic mediators(histamine and mast cell protease) in FA mice.In addition,HK-L.paracasei JY56 also could alleviate OVA-induced FA by suppressing T helper(Th)2 and Th17-type immune responses,which was evidenced by the regulation of splenic lymphocyte subpopulations and associated cytokine secretion.Moreover,jejunal histological analysis and intestinal barrier function related gene expression measurement were performed to verify the intestinal barrier repair of HK-L.paracasei JY56.Meanwhile,the TLR4/NF-κB inflammatory pathway activation was inhibited by HK-L.paracasei JY56 at gene and protein levels.Finally,HK-L.paracasei JY56 was performed to modulate the gut microbiota structure and increase the levels of short-chain fatty acids.In conclusion,HK-L.paracasei JY56 could alleviate OVA-induced FA in multiple ways,and this study provides a theoretical basis for the application of inactivated probiotics in functional foods for FA.展开更多
Many studies have shown that the development of allergic asthma is associated with intestinal microbiota dysbiosis.Based on the gut-lung axis theory,probiotic intervention may be a potential strategy for respiratory d...Many studies have shown that the development of allergic asthma is associated with intestinal microbiota dysbiosis.Based on the gut-lung axis theory,probiotic intervention may be a potential strategy for respiratory diseases.Lacticaseibacillus paracasei K56 was reported to regulate gut microbiota in mice.However,its effect on allergic asthma has not been reported.In this study,we investigated the effect of the K56 on ovalbumininduced asthma and its possible mechanisms.Our results showed that K56 reduced asthma symptoms and inflammatory cell infiltration in the lung of asthmatic mice.And K56 regulated the differentiation of helper T cells in the lung and intestine.Results from 16S r RNA gene sequencing showed that K56 prophylaxis significantly elevated the richness of Akkermansia and Burkholderia.Meanwhile,K56 abrogated the decrease in the levels of short-chain fatty acids(SCFAs)in the feces.In addition,a rebound in the m RNA expression of the SCFA receptors was observed after K56 prophylaxis.Notably,the regulatory T cell(Treg)frequencies and the FFAR3 levels were positively correlated.These results suggest that K56 could attenuate asthma,possibly by modulating the intestinal microbiota and regulating Treg differentiation through SCFA metabolized.Our study showed that K56 may be used as a probiotic to prevent pulmonary inflammation and dysbiosis of the intestinal microbiota in allergic asthma.展开更多
基金co-financed by the International Science&Technology Cooperation Program of Hainan Province(GHYF2023009)Jiangsu Provincial Key Research and Development Program(BE2022325)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0777)Qing Lan Project of Jiangsu Province and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.
基金supported by the Natural Science Foundation of Heilongjiang Province of China (LH2023C033)。
文摘Food allergy(FA) is an aberrant immune response triggered by the ingestion of a food antigen.Ovalbumin(OVA)-sensitized and challenged BALB/c mice were orally administered heat-killed(HK)-Lactobacillus paracasei JY56.In this work,HK-L.paracasei JY56 alleviated the FA-induced decrease in body weight and rectal temperature and reduced the allergy score.Serum analysis showed that HK-L.paracasei JY56 reduced the levels of specific antibodies(OVA-specific Immunoglobulin E(sIgE) and OVA-specific Immunoglobulin G(sIgG)) and allergic mediators(histamine and mast cell protease) in FA mice.In addition,HK-L.paracasei JY56 also could alleviate OVA-induced FA by suppressing T helper(Th)2 and Th17-type immune responses,which was evidenced by the regulation of splenic lymphocyte subpopulations and associated cytokine secretion.Moreover,jejunal histological analysis and intestinal barrier function related gene expression measurement were performed to verify the intestinal barrier repair of HK-L.paracasei JY56.Meanwhile,the TLR4/NF-κB inflammatory pathway activation was inhibited by HK-L.paracasei JY56 at gene and protein levels.Finally,HK-L.paracasei JY56 was performed to modulate the gut microbiota structure and increase the levels of short-chain fatty acids.In conclusion,HK-L.paracasei JY56 could alleviate OVA-induced FA in multiple ways,and this study provides a theoretical basis for the application of inactivated probiotics in functional foods for FA.
基金supported by grants from the National Natural Science Foundation of China(82174113,81473656)National Center of Technology Innovation for Dairy(No.2023-JSGG-15)。
文摘Many studies have shown that the development of allergic asthma is associated with intestinal microbiota dysbiosis.Based on the gut-lung axis theory,probiotic intervention may be a potential strategy for respiratory diseases.Lacticaseibacillus paracasei K56 was reported to regulate gut microbiota in mice.However,its effect on allergic asthma has not been reported.In this study,we investigated the effect of the K56 on ovalbumininduced asthma and its possible mechanisms.Our results showed that K56 reduced asthma symptoms and inflammatory cell infiltration in the lung of asthmatic mice.And K56 regulated the differentiation of helper T cells in the lung and intestine.Results from 16S r RNA gene sequencing showed that K56 prophylaxis significantly elevated the richness of Akkermansia and Burkholderia.Meanwhile,K56 abrogated the decrease in the levels of short-chain fatty acids(SCFAs)in the feces.In addition,a rebound in the m RNA expression of the SCFA receptors was observed after K56 prophylaxis.Notably,the regulatory T cell(Treg)frequencies and the FFAR3 levels were positively correlated.These results suggest that K56 could attenuate asthma,possibly by modulating the intestinal microbiota and regulating Treg differentiation through SCFA metabolized.Our study showed that K56 may be used as a probiotic to prevent pulmonary inflammation and dysbiosis of the intestinal microbiota in allergic asthma.
