First evidence of systemic infection and specific cytotoxic T lymphocyte immune response evoked by oral infection with recombinant Salmonella enterica serovar Albany-Ovalbumin in C57BL/6 mice.

Our group isolated Salmonella enterica serovar Albany from food and feces of wild captive carnivores in a zoo from northwestern Mexico. This serovar was also associated with the death of an ocelot (Leopardus pardalis) in the same zoo. Another group associated S. Albany with the death of a human patient. It is due to this zoonotic potential that the in vivo study of the host-S. Albany relationship is critical. The recombinant S. Albany-Ovalbumin (rSAO) strain was used to analyze a murine oral infection and its specific cytotoxic T lymphocyte (CTL) response. Our results have shown for the first time that rSAO establishes a systemic infection and evokes epitope-specific lysis with a Th1-like cytokine profile in vivo.

Profiling of circulating chromosome 21-encoded microRNAs, miR-155, and let-7c, in down syndrome.

BACKGROUND: Down syndrome (DS) is the most common chromosomal survival aneuploidy. The increase in DS life expectancy further heightens the risk of dementia, principally early-onset Alzheimer's disease (AD). AD risk in DS is higher, considering that this population may also develop metabolic diseases such as obesity, dyslipidemias, and diabetes mellitus. The extra genetic material that characterizes DS causes an imbalance in the genetic dosage, including over-expression of AD's key pathophysiological molecules and the gene expression regulators, the microRNAs (miRNAs). Two miRNAs, chromosome 21-encoded, miR-155, and let-7c, are associated with cognitive impairment and dementia in adults; but, expression dynamics and relationship with clinical variables during the DS's lifespan had remained hitherto unexplored. METHODS: The anthropometric, clinical, biochemical, and profile expression of circulating miR-155 and let-7c were analyzed in a population of 52 control and 50 DS subjects divided into the young group (Aged ≤20 years) and the adult group (Aged ≥21 years). RESULTS: The expression changes for miR-155 were not significant; nevertheless, a negative correlation with HDL-Cholesterol concentrations was observed. Notably, let-7c was over-expressed in DS from young and old ages. CONCLUSION: Overall, our results suggest that let-7c plays a role from the early stages of DS's cognitive impairment while overexpression of miR-155 may be related to lipid metabolism changes. Further studies of both miRNAs will shed light on their potential as therapeutic targets to prevent or delay DS's cognitive impairment.

Cloning and Recombinant Expression of Elongation Factor-1α of Leishmania mexicana.

Leishmania mexicana is an intracellular parasite that causes cutaneous leishmaniasis (CL) in some countries, including Mexico. Recently, we identified the elongation factor-1α (EF-1α) of L. mexicana by immunoproteomic analysis. In Leishmania donovani, this molecule has been reported as a virulence factor involved in downregulation of macrophages by no-canonical function when EF-1α interacts with protein tyrosine phosphatase-1 (SHP-1). However, in L. mexicana the key role of EF-1α in host-parasite relationship has not been elucidated, by this reason we started with cloning and recombinant expression of this antigen. A sequence of 1350 bp corresponding to EF-1α (EF-Lm) full-length gene was amplified from genomic DNA of L. mexicana (GenBank: MG256973); this gene contains only one nucleotide change: C464T, compared with L. mexicana reference sequence (GenBank: FR799570.1). The gene cloned (EF-Lm) codes for a protein of 449 residues. It was expressed in Escherichia coli and purified as 63 kDa sumo-fusion protein, which was recognized in the sera of patients diagnosed with CL. Our results show that EF-Lm is immunogenic during infection, and the rEF-Lm could be used for further analyses in the host-parasite relationship.

Synthesis of new quinazolin-2,4-diones as anti-Leishmania mexicana agents.

The quinazolin-2,4-dione moiety is found in many compounds with important biological activities making it a target for its synthesis. In this work, a one-pot three-step synthesis of new quinazolin-2,4-diones from phthalic anhydrides and their activity against Leishmania mexicana are described. The new quinazolin-2,4-diones were isolated with yields in the range of 32-70 %. All compounds displayed lower cytotoxicity in RAW 264.7 macrophage over miltefosine. Compound 6,7-dichloro-3-phenylquinazoline-2,4(1H,3H)-dione (6e) displayed an attractive profile which includes anti-Leishmania mexicana activity ([Formula: see text] [Formula: see text]M), much lower cytotoxic activity ([Formula: see text] [Formula: see text]M) and a high selective index ([Formula: see text]) proving to be superior to miltefosine.

Immunoproteomic Identification of p29 Antigen as the Elongation Factor-1α of Leishmania mexicana.

Previously, we identified five Leishmania mexicana antigens reacting with antibodies from cutaneous leishmaniasis patients, designated on the basis of their molecular weights as p26 (pI 7.8), p27 (pI 8.1), p28 (pI 8.6), p29 (pI 8.5), and p31 (pI 9.0). Among these antigens, p29 was most strongly recognized by the antibodies. Thereafter, p29 was identified as elongation factor-1α (EF-1α) of Leishmania mexicana through mass spectrometry analysis and western blot using a commercial antibody that reacted with EF-1α from different species. Our results showed that the p29 antigen of Leishmania mexicana is EF-1α.