Intracellular Accumulation of Trehalose Protects Lactococcus lactis from Freeze-Drying Damage and Bile Toxicity and Increases Gastric Acid Resistance

Abstract

Interleukin-10 (IL-10) is a promising candidate for the treatment of inflammatory bowel disease. Intragastric administration of Lactococcus lactis genetically modified to secrete IL-10 in situ in the intestine was shown to be effective in healing and preventing chronic colitis in mice. However, its use in humans is hindered by the sensitivity of L. lactis to freeze-drying and its poor survival in the gastrointestinal tract. We expressed the trehalose synthesizing genes from Escherichia coli under control of the nisin-inducible promoter in L. lactis. Induced cells accumulated intracellular trehalose and retained nearly 100% viability after freeze-drying, together with a markedly prolonged shelf life. Remarkably, cells producing trehalose were resistant to bile, and their viability in human gastric juice was enhanced. None of these effects were seen with exogenously added trehalose. Trehalose accumulation did not interfere with IL-10 secretion or with therapeutic efficacy in murine colitis. The newly acquired properties should enable a larger proportion of the administered bacteria to reach the gastrointestinal tract in a bioactive form, providing a means for more effective mucosal delivery of therapeutics.

Improving gastric transit, gastrointestinal persistence and therapeutic efficacy of the probiotic strain Bifidobacterium breve UCC2003

“…In any case, improved survival of the complemented strain in gastric juice containing added betaine suggests that it is the compatible solute (accumulated via BetL) that is responsible for the observed increased tolerance to the gastric juice. Interestingly, in support of this observation Termont et al (2006) recently reported improved tolerance to gastric juice in a Lactococcus lactis strain expressing trehalose-synthesizing genes from E. coli, suggesting a protective role for compatible solutes in the gastric environment.…”

Bioengineered probiotics, a strategic approach to control enteric infections

“…Similarly, cloning of the trehalose synthesis gene (ostAB) from E. coli into Lactococcus lactis protected recombinant bacteria from freeze-drying, bile toxicity, and resistance to gastric acid. 59 Furthermore, cloning of betL into Bifidobacterium breve UCC2003 significantly improved its survival in gastric juice thus improving its therapeutic attributes. 60 …”

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“…However, the use of bacteria in humans is hampered by the susceptibility to the lyophilization process and bacterial death within the gastrointestinal tract (GIT). In this context, more efficient means of delivery at the mucosal level for therapeutic lactic bacteria are being developed [10][11][12].…”