Beneficial effect of auto-aggregating Lactobacillus crispatus on experimentally induced colitis in mice.

We tested the therapeutic relevance of auto aggregation in lactobacilli by comparing the effect on DSS induced colitis of viable Lactobacillus crispatus M247, isolated from healthy humans, to L. crispatus MU5, an isogenic spontaneous mutants of M247, the latter lacking the auto aggregation phenotype which allows the adhesion to human mucus. Aggregating L. crispatus M247, but not the non-aggregating MU5, was retrievable from mice feces and adherent to the colonic mucosa. Daily administration of L. crispatus M247, but not heat killed L. crispatus M247 or aggregation deficient L. crispatus MU5, dose-dependently reduced the severity of DSS colitis. Indeed, L. crispatus MU5 administered in a 30% sucrose solution, known to restore the aggregation phenotype, had a protective effect comparable to mice receiving L. crispatus M247. These results indicate that a surface-mediated property such as aggregation may play a pivotal role in the protective effects obtained by dietary supplementation with L. crispatus M247 during colitis.

Lymphocytes endowed with colon-selective homing and engineered to produce TGF-beta1 prevent the development of dinitrobenzene sulphonic acid colitis.

BACKGROUND: Gene therapy is an attractive approach to the treatment of inflammatory diseases. However, the lack of tissue targeting of available vectors jeopardizes their clinical use. AIMS: Since alpha4beta7 integrin mediates lymphocyte homing to the intestinal mucosa, we tested the possibility of in-vitro engineering alpha4beta7-bearing lymphocytes to restrict the production of a therapeutic cytokine, transforming growth factor (TGF)-beta1, to within the colonic mucosa. METHODS: Lymphocytes were isolated from colonic lamina propria or spleen and transfected with either pC1 or pC1/TGF-beta1. RESULTS: Transfected spleen and lamina propria cells released TGF-beta1 for up to 5 days in vitro and administration of 107 spleen cells, but not 106 lamina propria or spleen cells, to normal mice caused a significant rise in circulating TGF-beta1. Following intrarectal injection of dinitrobenzene sulphonic acid, intraperitoneal administration of lamina propria or spleen cells transfected with pC1/TGF-beta1, but not pC1, significantly reduced colitis-associated body weight loss, colonic myeloperoxidase (MPO) activity, interleukin-1beta levels, and macroscopic and microscopic inflammatory damage. Vector-specific TGF-beta1 mRNA transcripts were detectable in the colon and liver following injection of lamina propria lymphocytes, and in the spleen, liver and colon following administration of spleen lymphocytes. Incubation of pC1/TGF-beta1-transfected lamina propria lymphocytes with anti-alpha4beta7 integrin antibody blocked their protective effects and caused the disappearance of vector-specific TGF-beta1 transcripts from the colonic mucosa. CONCLUSION: We conclude that lymphocytes are an efficient vehicle for transient gene therapy and that cells bearing alpha4beta7 integrins preferentially deliver therapeutic genes to the colonic mucosa.