Paula S. Santos

Epitope-Based Vaccines with the Anaplasma marginale MSP1a Functional Motif Induce a Balanced Humoral and Cellular Immune Response in Mice

Bovine anaplasmosis is a hemoparasitic disease that causes considerable economic loss to the dairy and beef industries. Cattle immunized with the Anaplasma marginale MSP1 outer membrane protein complex presents a protective humoral immune response; however, its efficacy is variable. Immunodominant epitopes seem to be a key-limiting factor for the adaptive immunity. We have successfully demonstrated that critical motifs of the MSP1a functional epitope are essential for antibody recognition of infected animal sera, but its protective immunity is yet to be tested. We have evaluated two synthetic vaccine formulations against A. marginale, using epitope-based approach in mice. Mice infection with bovine anaplasmosis was demonstrated by qPCR analysis of erythrocytes after 15-day exposure. A proof-of-concept was obtained in this murine model, in which peptides conjugated to bovine serum albumin were used for immunization in three 15-day intervals by intraperitoneal injections before challenging with live bacteria. Blood samples were analyzed for the presence of specific IgG2a and IgG1 antibodies, as well as for the rickettsemia analysis. A panel containing the cytokines’ transcriptional profile for innate and adaptive immune responses was carried out through qPCR. Immunized BALB/c mice challenged with A. marginale presented stable body weight, reduced number of infected erythrocytes, and no mortality; and among control groups mortality rates ranged from 15% to 29%. Additionally, vaccines have significantly induced higher IgG2a than IgG1 response, followed by increased expression of pro-inflammatory cytokines. This is a successful demonstration of epitope-based vaccines, and protection against anaplasmosis may be associated with elicitation of effector functions of humoral and cellular immune responses in murine model.

Biochemical and functional characterization of a C-type lectin (BpLec) from Bothrops pauloensis snake venom.

In the present work, we report the isolation and partial biochemical characterization of BpLec, a C-type lectin purified from Bothrops pauloensis venom by one chromatographic step on an affinity agarose column immobilized with d-galactose. This protein was homogeneous by SDS-PAGE under reducing and nonreducing conditions, and was shown to be a 33.6 kDa homodimer by MALDI TOF analysis. BpLec presented an isoeletric point of 5.36. Its partial sequence of 132 amino acids for each subunit, determined by Edman degradation, revealed high identity (between 86% and 95%) when aligned with sequences of other related proteins. BpLec was capable of agglutinating native dog and cat erythrocytes and this activity was inhibited by β-galactosides and EDTA. Its hemagglutinating activity was abolished at high temperatures and stable in any pH range. BpLec was effective in inhibiting Gram-positive but not Gram-negative bacteria. In addition, BpLec agglutinated promastigote forms of Leishmania (Leishmania) amazonensis.

The interaction of AGT and NOS3 gene polymorphisms with conventional risk factors increases predisposition to hypertension

Renin-angiotensin and kallikrein-kinin systems are interconnected, regulating blood pressure homeostasis. We have demonstrated the interactions among polymorphisms of the angiotensinogen (AGT) and endothelial nitric oxide synthase (NOS3) genes and conventional risk factors affecting the hypertension occurrence. Individuals were recruited (n=192) and classified into hypertensive (HG; n=140) and normotensive (NG; n=52) groups. The genotypic distribution of the Met235Thr (AGT) and Glu298Asp (NOS3) polymorphisms demonstrated that both are independent risk factors of hypertension (p=0.02 and p=0.008, respectively). The concomitant presence of these polymorphisms in the HG group was significantly different (p=0.001) from the NG. Both gene polymorphisms presented an additive effect for the unfavourable alleles T and A, respectively, and 95% of the double mutant homozygotes were classified into the HG. Specific interactions among certain conventional factors and the presence of at least one unfavourable allele presented significant odds towards hypertension. Blood pressure homeostasis was affected by genetic polymorphisms conditioned by the T and A alleles of the AGT and NOS3 genes, respectively, which acted independently. However, their interaction with smoking, sedentariness, age and total cholesterol may have increased the predisposition to hypertension, which may explain most of the hypertension cases.

Glibenclamide treatment modulates the expression and localization of myosin-IIB in diabetic rat brain.

BACKGROUND Myosin-IIB is a non-muscle isoform in the brain with increased expression in the brains of diabetic rats. Chronic hyperglycemia caused by diabetes can impair learning and memory. Oral hypoglycemic agents such as glibenclamide have been used to control hyperglycemia. We report changes in the expression and distribution of myosin-IIB in the frontal cortex and hippocampus of diabetic rats treated with glibenclamide. METHODS The brains were removed after 43 days of treatment with glibenclamide (6 mg/kg bw orally), homogenized and analyzed by Western blotting, qRT-PCR and immunohistochemistry. RESULTS Myosin-IIB expression increased in the brains of diabetic rats. However, protein expression returned to control levels when treated with glibenclamide. In addition, the expression of MYH10 gene encoding non-muscle myosin heavy chain-B decreased in diabetic rats treated with glibenclamide. Moreover, we found weak myosin-IIB labeling in the hippocampus and frontal cortex of rats treated with glibenclamide. Therefore, the expression of myosin-IIB is affected by diabetes mellitus and may be modulated by glibenclamide treatment in rats. Structural changes in the hippocampus and prefrontal cortex are reversible, and glibenclamide treatment may reduce the patho-physiological changes in the brain. CONCLUSIONS Our findings can contribute to the understanding of the regulation of myosins in the brains of diabetic rats.

Altered Leukocyte Sphingolipid Pathway in Breast Cancer

Sphingolipid metabolism pathway is essential in membrane homeostasis, and its dysfunction has been associated with favorable tumor microenvironment, disease progression, and chemotherapy resistance. Its major components have key functions on survival and proliferation, with opposing effects. We have profiled the components of the sphingolipid pathway on leukocytes of breast cancer (BC) patients undergoing chemotherapy treatment and without, including the five sphingosine 1-phosphate (S1P) receptors, the major functional genes, and cytokines, in order to better understand the S1P signaling in the immune cells of these patients. To the best of our knowledge, this is the first characterization of the sphingolipid pathway in whole blood of BC patients. Skewed gene profiles favoring high SPHK1 expression toward S1P production during BC development was observed, which was reversed by chemotherapy treatment, and reached similar levels to those found in healthy donors. Such levels were also correlated with high levels of TNF-α. Our data revealed an important role of the sphingolipid pathway in immune cells in BC with skewed signaling of S1P receptors, which favored cancer development even under chemotherapy, and may probably be a trigger of cancer resistance. Thus, these molecules must be considered as a target pathway for combined BC therapeutics.

Frontiers of biology in human diseases: strategies for biomolecule's discovery, nanobiotechnologies and biophotonics.

The current frontiers in biological sciences demand an interface among disciplines of biology, chemistry, and physics to achieve new paradigms in applied nanobiotechnologies to health. An extraordinary amount of information on genomes, transcriptomes, proteomes, metabolomes, miRNAs, lncRNAs, protein editing, post-translational modifications, exosomes, molecular interactions, cell signaling, structural biology, immunology, cellular receptors, interactomes, and bioinformatics are opening new possibilities for biological manipulations aiming improved diagnostics and therapeutics. New rationale is required to use available technologies that intersect among imaging, electrochemistry, biophotonics, nanotechnologies and combinatorial molecules. A massive, diverse and broad knowledge on multidisciplinary aspects have been provided in the last few years, and the challenge is to combine recent technologies and information to identify revolutionary platforms for the progression of life sciences. This brief review will discuss examples of epitope-based and combinatorial antibody and nucleic acid (aptamers) selection technologies in association with nanobiotechnologies and their multiple applications in biomedical sciences.