Márcia Regina Cominetti

Physical Exercise in MCI Elderly Promotes Reduction of Pro-Inflammatory Cytokines and Improvements on Cognition and BDNF Peripheral Levels

The benefits of physical exercise to reduce low-grade inflammation and improve Brain-Derived Neurotrophic Factor (BDNF) levels and cognitive function became a growing field of interest. Low-grade inflammation is common during aging and seems to be linked to neurodegenerative process. Regular physical exercises can help to reduce pro-inflammatory cytokines levels and to improve BDNF peripheral concentrations. The main goal of this research was to analyze the effects of a 16-week multimodal physical exercise program on peripheral BDNF levels and on Tumor Necrosis-α (TNF-α) and Interleukin- 6 (IL-6) as pro-inflammatory markers in cognitive healthy elderly individuals and in elderly with mild cognitive impairment (MCI). Cognitive functions were assessed by the Montreal Cognitive Assessment (MoCA) prior to and after the intervention. Thirty cognitively healthy participants and thirty-seven MCI participants were assigned to the control (CG) and trained (TG) groups. The TG participated in a multimodal physical training program for a 16-week period. The results showed a significant between-subjects interaction, which indicates the beneficial contribution of training on the reduction of TNF-α (p=0.001) and IL-6 (p<0.001) and on the improvement of BDNF (p<0.001) peripheral concentrations. Cognitive functions also presented significant improvements for MCI trained group (p=0.03). In conclusion, physical exercise was effective to reduce pro-inflammatory cytokines and to improve BDNF peripheral levels, with positive reflexes on cognition. To the best of our knowledge, this is the first study that evaluated longitudinally the effects of a multimodal physical exercises protocol on peripheral concentrations of pro-inflammatory cytokines and cognition performance in elderly MCI individuals.

Characterization and partial purification of a lectin from the hemolymph of the white shrimp Litopenaeus schmitti.

The agglutinating activity of the hemolymph of Litopenaeus schmitti is insensitive to calcium and specific for acetylated sugars, particularly sialic acid (Neu5Ac) and O-sialoglycoconjugates (bovine submaxillary mucin) and has varying specificity for different LPS, which may suggest a putative role in microorganism recognition. Affinity chromatography on fetuin-agarose of the agglutinin resulted in a 220 kDa band (lectin), and a 82.5 kDa band, which probably is hemocyanin. The 220 kDa protein consists of 31 and 34 kDa subunits, suggesting that this lectin is multimeric. The lectin molecular mass was estimated by gel filtration to be 153+/-10 kDa. The hemolymph of L. schmitti comprises at least another soluble lectin, with distinct chemical and carbohydrate specificity than the 220 kDa lectin.

The three-dimensional structure of bothropasin, the main hemorrhagic factor from Bothrops jararaca venom: Insights for a new classification of snake venom metalloprotease subgroups

Bothropasin is a 48kDa hemorrhagic PIII snake venom metalloprotease (SVMP) isolated from Bothrops jararaca, containing disintegrin/cysteine-rich adhesive domains. Here we present the crystal structure of bothropasin complexed with the inhibitor POL647. The catalytic domain consists of a scaffold of two subdomains organized similarly to those described for other SVMPs, including the zinc and calcium-binding sites. The free cysteine residue Cys189 is located within a hydrophobic core and it is not available for disulfide bonding or other interactions. There is no identifiable secondary structure for the disintegrin domain, but instead it is composed mostly of loops stabilized by seven disulfide bonds and by two calcium ions. The ECD region is in a loop and is structurally related to the RGD region of RGD disintegrins, which are derived from PII SVMPs. The ECD motif is stabilized by the Cys277-Cys310 disulfide bond (between the disintegrin and cysteine-rich domains) and by one calcium ion. The side chain of Glu276 of the ECD motif is exposed to solvent and free to make interactions. In bothropasin, the HVR (hyper-variable region) described for other PIII SVMPs in the cysteine-rich domain, presents a well-conserved sequence with respect to several other PIII members from different species. We propose that this subset be referred to as PIII-HCR (highly conserved region) SVMPs. The differences in the disintegrin-like, cysteine-rich or disintegrin-like cysteine-rich domains may be involved in selecting target binding, which in turn could generate substrate diversity or specificity for the catalytic domain.

Alternagin-C, a disintegrin-like protein from the venom of Bothrops alternatus, modulates alpha2ß1 integrin-mediated cell adhesion, migration and proliferation

The alpha2beta1 integrin is a major collagen receptor that plays an essential role in the adhesion of normal and tumor cells to the extracellular matrix. Alternagin-C (ALT-C), a disintegrin-like protein purified from the venom of the Brazilian snake Bothrops alternatus, competitively interacts with the alpha2beta1 integrin, thereby inhibiting collagen binding. When immobilized in plate wells, ALT-C supports the adhesion of fibroblasts as well as of human vein endothelial cells (HUVEC) and does not detach cells previously bound to collagen I. ALT-C is a strong inducer of HUVEC proliferation in vitro. Gene expression analysis was done using an Affimetrix HU-95A probe array with probe sets of approximately 10,000 human genes. In human fibroblasts growing on collagen-coated plates, ALT-C up-regulates the expression of several growth factors including vascular endothelial growth factor, as well as some cell cycle control genes. Up-regulation of the vascular endothelial growth factor gene and other growth factors could explain the positive effect on HUVEC proliferation. ALT-C also strongly activates protein kinase B phosphorylation, a signaling event involved in endothelial cell survival and angiogenesis. In human neutrophils, ALT-C has a potent chemotactic effect modulated by the intracellular signaling cascade characteristic of integrin-activated pathways. Thus, ALT-C acts as a survival factor, promoting adhesion, migration and endothelial cell proliferation after binding to alpha2beta1 integrin on the cell surface. The biological activities of ALT-C may be helpful as a therapeutic strategy in tissue regeneration as well as in the design of new therapeutic agents targeting alpha2beta1 integrin.

Purification and differential biological effects of ginger-derived substances on normal and tumor cell lines

This study describes an optimization of [6]-, [8]- and [10]-gingerol isolation and purification in semi-preparative HPLC scale and their anti-proliferative activity. The gingerols purification was carried out in HPLC system using a Luna-C₁₈ and the best mobile phase evaluated was MeOH/H₂O (75:25, v/v). This new methodology for the gingerols isolation was very effective, since considerable amounts (in the range of milligrams) with a good purity degree (∼98%) were achieved in 30 min of chromatographic run. [6]-, [8]- and [10]-Gingerol purified by this methodology inhibited the proliferation of MDA-MB-231 tumor cell line with IC₅₀ of 666.2±134.6 μM, 135.6±22.6 μM and 12.1±0.3 μM, respectively. These substances also inhibited human fibroblasts (HF) cell proliferation, however in concentrations starting from 500 μM. In conclusion, our results demonstrate an optimization of gingerols isolation and their specific anti-proliferative activities against tumor cells, suggesting their use as important models for drug design in an attempt to develop new compounds with fewer side effects when compared to conventional chemotherapy.

Physical exercise improves peripheral BDNF levels and cognitive functions in mild cognitive impairment elderly with different bdnf Val66Met genotypes.

The benefits of physical exercise on improvements in brain-derived neurotrophic factor (BDNF) levels and cognitive functioning have been reported in the literature. However, the variability of individual responses may be linked to genetic differences. BDNF is considered one of the most plausible factors involved in the cognitive benefits associated with physical activity practice. A single nucleotide polymorphism localized in the gene that codes BDNF results in a missense mutation that promotes an amino acid substitution (Val66Met) in the protein. This process has been associated with decreased levels of BDNF secretion, with corresponding impairments in specific cognitive functions. Therefore, the objective of this study was to analyze the effects of a multimodal physical exercise program on peripheral BDNF levels and cognitive functions in elderly individuals with mild cognitive impairment (MCI). The participants were genotyped for the BDNF Val66Met polymorphism. Cognitive functions were assessed by the Montreal Cognitive Assessment (MoCA) prior to and after the intervention. Forty-five participants were assigned to the control and trained groups. The trained group participated in a multimodal physical training for a 16-week period. The results showed a significant between-subjects interaction (p < 0.05), which indicates the beneficial contribution of training on cognitive functions independent of the BDNF genotype. However, only participants with BDNF-Met genotypes exhibited significant improvements in peripheral BDNF levels. The BDNF genotype appears to modulate the effects of physical exercise on BDNF secretion, but it does not influence cognition. This is the first study that evaluated the influence of a BDNF polymorphism on physical activity and cognition performance in elderly MCI individuals.

Inhibition of platelets and tumor cell adhesion by the disintegrin domain of human ADAM9 to collagen I under dynamic flow conditions

This work aimed to investigate the role of the disintegrin domain of the human ADAM9 (ADAM9D) on the adhesion of breast tumor cells and platelets to collagen I, in a dynamic flow assay to simulate in vivo shear conditions. Recombinant ADAM9D was able to support tumor cell adhesion through binding to the beta1 integrin subunit and also to inhibit the invasion through matrigel in vitro. In a dynamic flow assay ADAM9D inhibited about 75% and 65% of MDA-MB-231 tumor cells and platelet adhesion to collagen I, respectively. In addition, it was demonstrated that alphaVbeta3 integrin is new interacting partner for ADAM9D. In conclusion, these results suggest a role for the disintegrin domain of ADAM9 in the metastatic process. Also, ADAM9D may be a tool for investigating the role of ADAMs in metastasis and cancer progression and for the design of selective inhibitors against the adhesion and extravasation of cancer cells.

(6)-gingerol as a Cancer Chemopreventive Agent: A Review of Its Activity on Different Steps of the Metastatic Process

For many years, ginger or ginger root, the rhizome of the plant Zingiber officinale, has been consumed as a delicacy, medicine, or spice. Several studies have been conducted on the medicinal properties of ginger against various disorders, including cancer. Cancer is the second leading cause of death, and chemoprevention is defined as the use of natural or synthetic substances to prevent cancer initiation or progression. Evidence that ginger-derived compounds have inhibitory effects on various cancer cell types is increasingly being reported in the scientific literature. In this review we focused on the cancer chemopreventive effects of [6]-gingerol, the major pungent component of ginger, and its impact on different steps of the metastatic process.

ADAM10 as a Biomarker for Alzheimer’s Disease: A Study with Brazilian Elderly

Alzheimer’s disease (AD) is the most common cause of dementia in people above age 65. Platelet studies with ADAM10 have shown that its expression is reduced in AD patients. The aim of this research was to compare the platelet levels of ADAM10 protein in two Brazilian elderly groups, considering the stages of the disease. The SDS-PAGE technique followed by Western blotting was used. Data were analyzed using comparison, correlation and association statistical methods. The results showed reduced platelet ADAM10 levels in AD elderly compared to non-AD subjects. The disease progression intensified this reduction. ADAM10 was the only statistically significant variable (p = 0.01) to increase the AD occurrence probability. The cutoff value of 0.4212 in the receiver operating characteristic curve captured sensitivity and specificity of 70 and 80.77%, respectively. Together with other clinical criteria, ADAM10 seems to be a relevant biomarker tool for early and accurate AD diagnosis.

The specificity of frutalin lectin using biomembrane models.

Frutalin is a homotetrameric alpha-d-galactose (d-Gal)-binding lectin that activates natural killer cells in vitro and promotes leukocyte migration in vivo. Because lectins are potent lymphocyte stimulators, understanding the interactions that occur between them and cell surfaces can help to the action mechanisms involved in this process. In this paper, we present a detailed investigation of the interactions of frutalin with phospho- and glycolipids using Langmuir monolayers as biomembrane models. The results confirm the specificity of frutalin for d-Gal attached to a biomembrane. Adsorption of frutalin was more efficient for the galactose polar head lipids, in contrast to the one for sulfated galactose, in which a lag time is observed, indicating a rearrangement of the monolayer to incorporate the protein. Regarding ganglioside GM1 monolayers, lower quantities of the protein were adsorbed, probably due to the farther apart position of d-galactose from the interface. Binary mixtures containing galactocerebroside revealed small domains formed at high lipid packing in the presence of frutalin, suggesting that lectin induces the clusterization and the forming of domains in vitro, which may be a form of receptor internalization. This is the first experimental evidence of such lectin effect, and it may be useful to understand the mechanism of action of lectins at the molecular level.