Current review of genetically modified lactic acid bacteria for the prevention and treatment of colitis using murine models

Inflammatory Bowel Diseases (IBD) are disorders of the gastrointestinal tract characterized by recurrent inflammation that requires lifelong treatments. Probiotic microorganisms appear as an alternative for these patients; however, probiotic characteristics are strain dependent and each probiotic needs to be tested to understand the underlining mechanisms involved in their beneficial properties. Genetic modification of lactic acid bacteria (LAB) was also described as a tool for new IBD treatments.The first part of this review shows different genetically modified LAB (GM-LAB) described for IBD treatment since 2000.Then, the two principally studied strategies are discussed (i) GM-LAB producing antioxidant enzymes and (ii) GM-LAB producing the anti-inflammatory cytokine IL-10. Different delivery systems, including protein delivery and DNA delivery, will also be discussed. Studies show the efficacy of GM-LAB (using different expression systems) for the prevention and treatment of IBD, highlighting the importance of the bacterial strain selection (with anti-inflammatory innate properties) as a promising alternative. These microorganisms could be used in the near future for the development of therapeutic products with anti-inflammatory properties that can improve the quality of life of IBD patients.Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: del Carmen, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Chatel, Jean Marc. Institut National de la Recherche Agronomique; FranciaFil: Miyoshi, Anderson. Universidade Federal do Minas Gerais; BrasilFil: Azevedo, Vasco. Universidade Federal do Minas Gerais; BrasilFil: Langella, Philippe. Institut National de la Recherche Agronomique; FranciaFil: Bermudez Humaran, Luis G.. Institut National de la Recherche Agronomique; FranciaFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Gnotobiotic rodents: an in vivo model to study microbe-microbe interactions

Germ-free rodents have no microorganisms living in or on them, allowing researchers to specifically control an animal’s microbiota through the direct inoculation of bacteria of interest. This strategy has been widely used to decipher host-microbe interactions as well as the role of microorganisms in both i) the development and function of the gut barrier (mainly the intestinal epithelium) and ii) homeostasis and its effects on human health and disease. However, this in vivo model also offers a more realistic environment than an assay tube in which to study microbe-microbe interactions, without most of the confounding interactions present in the intestinal microbiota of conventionally raised mice. This review highlights the usefulness of controlled-microbiota mice in studying microbe-microbe interactions. To this end, we summarize current knowledge on germ-free animals as an experimental model for the study of the ecology and metabolism of intestinal bacteria as well as of microbe-microbe interactions

The indigenous microbiota and its potential to exhibit probiotic properties

International audienceHumans harbour a different microbiota depending on the tissue considered. Most of the microorganisms are contained in the gastro-intestinal tract (GIT) and this gut microbiota represents approximately 1014 cells that correspond to the highest bacterial density for any ecosystem. Our microbiota represents a huge diversity in term of species and functions. A healthy gut microbiota is composed of a well-balanced community of three permanent residents termed symbionts (with beneficial effects), commensals (no effect), and pathobionts (potentially induce pathologies under certain situations), but no pathogens. The term dysbiosis (microbial imbalance) has been related to many different kinds of pathologies although it is not clear whether the imbalance of such a microbiota is a cause or a consequence of the illness. Nowadays, the challenge of linking microbiota to human health and disease is being tackled by different research teams around the world with the aim to investigate the implication of potential beneficial bacteria that could be decreased in the studied microbiota of patients. From this perspective, it could be interesting to use them as potential probiotics to try to resolve dysbioses

Uso de bacterias lácticas como vehículos de moléculas terapéuticas

La administración de moléculas terapéuticas a través de las mucosas presenta varias ventajas importantes sobre la administración sistémica clásica, tales como: reducción de efectos secundarios, fácil administración y la posibilidad de modular la respuesta inmune tanto sistémica como local. Las superficies de mucosas son los principales sitios de interacción entre un organismo y su medio ambiente y por lo tanto representan la principal puerta de entrada de patógenos. En los últimos 15 años, una gran cantidad de trabajos científicos ha reportado una variedad de vehículos de moléculas terapéuticas, vacunas principalmente, para una inmunización efectiva a nivel de mucosas. Este tipo de administración puede además, inducir una eficiente respuesta inmune sistémica con un menor riesgo de provocar efectos colaterales secundarios como lo hacen las vacunas sistémicas clásicas. Adicionalmente, la inmunización por vía mucosal se realiza de una manera más simple sin la necesidad de jeringas y agujas, eliminando así la necesidad de personal capacitado, lo cual representa una clara ventaja en programas de vacunación masiva. Sin embargo, una desventaja importante de este tipo de administración de moléculas terapéuticas, es que una gran cantidad de proteína debe ser administrada, debido al hecho de que la mayoría de la proteína será degradada en las superficies de mucosas tales como el tracto gastro-intestinal por las enzimas digestivas y las condiciones hostiles de este sitio. Por lo tanto, el desarrollo de nuevos vectores, capaces de entregar y/o expresar eficientemente moléculas terapéuticas in situ representa un reto biotecnológico.Fil: Cortes Perez, Naima G.. Institut National de la Recherche Agronomique; FranciaFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Langella, Philippe. Institut National de la Recherche Agronomique; FranciaFil: Bermudez Humaran, Luis. Institut National de la Recherche Agronomique; Franci

Intranasal administration with recombinant Lactococcus lactis expressing heme oxygenase-1 reduces hyperoxia-induced lung inflammation in rat pups

To evaluate the effects of a recombinant strain of Lactococcus lactis secreting bioactive heme oxygenase-1 (LL-HO-1) in a model of hyperoxia-induced lung injury in rat pups Intranasal administration with LL-HO-1 significantly reduced hyperoxia-induced lung injury as demonstrated by a decreased wet/dry ratio, myeloperoxidase activity in lung tissue, tumor necrosis factor alpha levels in bronchoalveolar lavage (BAL) fluid, and attenuated lung injury scores. Although expression of HO-1 and NADPH oxidase-1 and production of superoxide in lung tissue were not affected by LL-HO-1 treatment, HO-1 levels in nasal mucosa and interleukin-10 concentrations in BAL fluid significantly increased compared with the hyperoxia control group Intranasal administration of LL-HO-1 protects against hyperoxia-induced lung damage, apparently through attenuation of inflammation

Lactococcus lactis, an efficient cell factory for recombinant protein production and secretion

International audienceThe use of Gram-positive bacteria for heterologous protein production proves to be a useful choice due to easy protein secretion and purification. The lactic acid bacterium Lactococcus lactis emerges as an attractive alternative to the Gram-positive model Bacillus subtilis. Here, we review recent work on the expression and secretion systems available for heterologous protein secretion in L. lactis, including promoters, signal peptides and mutant host strains known to overcome some bottlenecks of the process. Among the tools developed in our laboratory, inactivation of HtrA, the unique housekeeping protease at the cell surface, or complementation of the Sec machinery with B. subtilis SecDF accessory protein each result in the increase in heterologous protein yield. Furthermore, our lactococcal expression/secretion system, using both P(Zn)zitR, an expression cassette tightly controlled by environmental zinc, and a consensus signal peptide, SP(Exp4), allows efficient production and secretion of the staphylococcal nuclease, as evidenced by protein yields (protein amount/biomass) comparable to those obtained using NICE or P170 expression systems under similar laboratory conditions. Finally, the toolbox we are developing should contribute to enlarge the use of L. lactis as a protein cell factory