Ectopic Expression of Innate Immune Protein, Lipocalin-2, in Lactococcus lactis Protects Against Gut and Environmental Stressors.
Ectopic Expression of Innate Immune Protein, Lipocalin-2, in Lactococcus lactis Protects Against Gut and Environmental Stressors.
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DOI：
10.1097/mib.0000000000001134
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发表时间：
2017-07
影响因子：
4.9
通讯作者：
Vijay-Kumar M
中科院分区：
文献类型：
--
作者：
Saha P;Chassaing B;Yeoh BS;Viennois E;Xiao X;Kennett MJ;Singh V;Vijay-Kumar M
脂质运载蛋白2（Lcn 2）是一种多功能的先天免疫蛋白，其通过螯合细菌铁载体表现出抗微生物活性，调节铁稳态，并增强细胞对氧化应激的耐受性。在小鼠结肠炎模型中的研究已经证明，Lcn 2缺乏会加剧结肠炎发生，然而，Lcn 2补充的治疗潜力尚未阐明。鉴于其潜在的粘膜保护功能，我们在此研究了益生菌中Lcn 2的表达是否可以用于缓解实验性结肠炎。将小鼠Lcn 2克隆到pT 1 NX质粒中，并转化乳酸乳球菌以产生L.表达Lcn 2的乳酸菌（LactisLcn 2）或空质粒（LactisCon）。LactisLcn 2通过免疫印迹和ELISA进行表征，并测试其对大肠杆菌的抗菌效果。使用体外活力测定法测试LactisLcn 2和LactisCon耐受不利条件的能力。采用葡聚糖硫酸钠结肠炎模型研究LactisLcn 2和LactisCon的定植能力和治疗潜力。Lcn 2-抑制E.大肠杆菌中，肠杆菌素（E.大肠杆菌来源的铁载体）。LactisLcn 2在体外表现出对不利pH、高浓度胆汁酸和氧化应激的耐受性增强，并且在发炎的肠道中比LactisCon存活得更好。与这些特征一致，当给予患有DSS诱导的急性结肠炎的小鼠时，LactisLcn 2显示出比LactisCon更好的针对肠道炎症的粘膜保护。我们的研究结果表明，Lcn 2的表达可以用来增强益生菌在炎症过程中的存活能力，这可以进一步提高其治疗实验性结肠炎的疗效。
Lipocalin 2 (Lcn2) is a multifunctional innate immune protein that exhibits antimicrobial activity by the sequestration of bacterial siderophores, regulates iron homeostasis, and augments cellular tolerance to oxidative stress. Studies in the murine model of colitis have demonstrated that Lcn2 deficiency exacerbates colitogenesis, however, the therapeutic potential of Lcn2 supplementation has yet to be elucidated. In light of its potential mucoprotective functions, we herein investigated whether expression of Lcn2 in the probiotic bacterium can be exploited to alleviate experimental colitis. Murine Lcn2 was cloned into the pT1NX plasmid and transformed into Lactococcus lactis to generate L. lactis expressing Lcn2 (LactisLcn2) or the empty plasmid (LactisCon). LactisLcn2 was characterized by immunoblot and ELISA, and tested for its antimicrobial efficacy on Escherichia coli. The capacity of LactisLcn2 and LactisCon to withstand adverse conditions were tested using in vitro viability assays. Dextran sodium sulfate colitis model was employed to investigate the colonization ability and therapeutic potential of LactisLcn2 and LactisCon. Lcn2-derived from LactisLcn2 inhibited the growth of E. coli and reduced the bioactivity of enterobactin (E. coli-derived siderophore) in vitro. LactisLcn2 displayed enhanced tolerance to adverse pH, high concentration of bile acids and oxidative stress in vitro, and survived better in the inflamed gut than LactisCon. Consistent with these features, LactisLcn2 displayed better mucoprotection against intestinal inflammation than LactisCon when administered into mice with DSS-induced acute colitis. Our findings suggest that Lcn2 expression can be exploited to enhance the survivability of probiotic bacteria during inflammation, which could further improve its efficacy to treat experimental colitis.