Lactobacillus plantarum-derived indole-3-lactic acid ameliorates colorectal tumorigenesis via epigenetic regulation of CD8+ T cell immunity.

Previous studies have shown that Lactobacillus species play a role in ameliorating colorectal cancer (CRC) in a mouse model. However, the underlying mechanisms remain largely unknown. Here, we found that administration of a probiotic strain, Lactobacillus plantarum L168 and its metabolite, indole-3-lactic acid, ameliorated intestinal inflammation, tumor growth, and gut dysbiosis. Mechanistically, we indicated that indole-3-lactic acid accelerated IL12a production in dendritic cells by enhancing H3K27ac binding at the enhancer regions of IL12a that contributed to priming CD8+ T cell immunity against tumor growth. Furthermore, indole-3-lactic acid was found to transcriptionally inhibit Saa3 expression related to cholesterol metabolism of CD8+ T cells through changing chromatin accessibility and subsequent enhancing function of tumor-infiltrating CD8+ T cells. Together, our findings provide new insights into the epigenetic regulation of probiotics-mediated anti-tumor immunity and suggest the potential of L. plantarum L168 and indole-3-lactic acid to develop therapeutic strategies for patients with CRC.

Impact of Increased Hemoglobin on Spontaneous Intracerebral Hemorrhage.

BACKGROUND: Studies of the impact of increased hemoglobin on spontaneous intracerebral hemorrhage (ICH) are limited. The present study aimed to explore the effect of increased hemoglobin on ICH. METHODS: A retrospective single-center study using medical records from a database processed by univariate and multivariate analyses was performed in the People's Hospital of Tibet Autonomous Region in Lhasa, Tibet, China. RESULTS: The mean hemoglobin level in 211 patients with ICH was 165.03 ± 34.12 g/l, and a median hematoma volume was 18.5 ml. Eighty-eight (41.7%) patients had large hematomas (supratentorial hematoma ≥ 30 ml; infratentorial hematoma ≥ 10 ml). No differences in ICH risk factors between the groups with different hemoglobin levels were detected. Increased hemoglobin was independently associated with large hematomas [odds ratio (OR) 1.013, P = 0.023]. Increased hemoglobin was independently associated with ICH with subarachnoid hemorrhage (OR 1.014, P = 0.016), which was more pronounced in men (OR 1.027, P = 0.002). Increased hemoglobin was independently associated with basal ganglia hemorrhage and lobar hemorrhage in men (OR 0.986, P = 0.022; OR 1.013, P = 0.044, respectively) but not in women (P > 0.1). CONCLUSIONS: Increased hemoglobin was independently associated with large hemorrhage volume. Increased hemoglobin was independently associated with lobar hemorrhage in men and ICH with subarachnoid hemorrhage, which was more pronounced in men. Additional studies are needed to confirm our findings and explore potential mechanisms.

Subcutaneous and intranasal immunization with Stx2B-Tir-Stx1B-Zot reduces colonization and shedding of Escherichia coli O157:H7 in mice.

The type III secretion system of Escherichia coli O157:H7 is involved in colonization of mammalian hosts by the organism. The translocated intimin receptor (Tir) is inserted into the mammalian host cell plasma membrane in a hairpin loop topology with the central loop of the molecule exposed to the host cell surface and accessible for interaction with an LEE-encoded bacterial outer membrane adhesin called intimin. Shiga toxin type 1 and 2 produced by E. coli O157:H7 are responsible for hemolytic uremic syndrome and able to promote intestinal colonization. Zonula occludens toxin (Zot) is a single polypeptide chain encoded by the filamentous bacteriophage CTXφ of Vibrio cholerae. Zot binds a receptor on intestinal epithelial cells and increases mucosal permeability by affecting the structure of epithelial tight junctions. Because of these properties, Zot is a promising tool for mucosal drug and antigen (Ag) delivery. In the current study, we constructed a novel fusion protein carrying both of the immunogenic B subunits derived from the two toxins, Tir and Zot, designated Stx2B-Tir-Stx1B-Zot, expressed in the E. coli BL21 and harvested the purified protein by a simple GST·Bind Resin chromatography method. We used a streptomycin-treated mouse model to evaluate the efficacy of subcutaneous vs. intranasal administration of the vaccine. Following immunization, mice were infected with E. coli O157:H7 and feces were monitored for shedding. Immune responses against Stx2B-Tir-Stx1B-Zot, Stx2B-Tir-Stx1B and control agent (GST/PBS) were also monitored. Subcutaneous immunization of mice with Stx2B-Tir-Stx1B-Zot induced significant Stx2B-Tir-Stx1B-Zot-specific serum IgG antibodies but did not significantly induce any antigen-specific IgA in feces, whereas intranasal immunization elicited significant Stx2B-Tir-Stx1B-Zot-specific serum IgG antibodies with some animals developing antigen-specific IgA in feces. Mice that were immunized intranasally with Stx2B-Tir-Stx1B-Zot showed dramatically decreased E. coli O157:H7 shedding compared to those of Stx2B-Tir-Stx1B and control agent following experimental infection. Mice immunized subcutaneously with Stx2B-Tir-Stx1B-Zot or Stx2B-Tir-Stx1B both showed reduced shedding in feces, moreover, Stx2B-Tir-Stx1B-Zot did better. These results demonstrate the perspective for the use of Stx2B-Tir-Stx1B-Zot to prevent colonization and shedding of E. coli O157:H7.