Fat phenotype, associated factors and rs9939609 polymorphism of the FTO gene

O propósito deste foi sintetizar os principais resultados de estudos que analisaram a relação do polimorfismo de nucleotídeo simples (SNP) rs9939609 do gene FTO (fat mass and obesity associated), com a manifestação de sobrepeso / obesidade e suas co-morbidades e discutir a interação deste polimorfismo com os demais fatores promotores da obesidade. A busca foi realizada nas bases de dados MEDLINE, Highwire, Science Direct e SciELO, usando as palavras-chave: FTO rs9939609, obesity genetic, gene associated obesity, FTO contributes obesity. Os critérios de inclusão foram: artigos originais que envolveram seres humanos e que incluíram o rs9939609. Foram excluídos os artigos que analisaram o gene FTO em grupos com doenças hormonais pré-instaladas. Dos vários SNPs contidos no gene FTO, o rs9939609 tem sido o mais pesquisado. Este SNP é composto pelos alelos A e T, sendo os homozigotos A os mais susceptíveis ao desenvolvimento de sobrepeso / obesidade em todas as idades, principalmente, em populações caucasianas. Nessa situação, o controle dos fatores ambientais (alimentação e atividade física) pode prevenir o acúmulo excessivo de gordura. A obesidade está relacionada ao desenvolvimento de doenças crônicas não-transmissíveis. Foram observadas associações do rs9939609 com o perfil lipídico sanguíneo e a glicemia. A prática de exercícios físicos e a alimentação parecem ser os principais influenciadores no desenvolvimento do sobrepeso / obesidade e na instalação das co-morbidades associadas.The purpose of this work was to review the main results of studies that have analysed the relationship between the rs9939609 single nucleotide polymorphism (SNP) of the FTO gene and the manifestation of overweight/obesity with its associated co-morbidity, and to discuss the interaction of this polymorphism with the other factors which cause obesity. The search was performed using the MEDLINE, Highwire, Science Direct and SciELO databases, applying the following key words: FTO rs9939609, obesity genetic, gene associated obesity, FTO contributes obesity. Inclusion criteria were: original articles where the search was performed in humans and including the rs9939609. Articles that analysed the FTO gene associated with pre-installed hormonal diseases were excluded. Of the several SNP associated with the FTO gene, rs9939609 has been the most researched (studied). This SNP comprises the A and T alleles, with the A homozygote being most susceptible to the development of overweight/obesity in all age ranges, especially in the caucasian population. In this situation, the control of environmental factors (alimentation and physical activity) can prevent the excessive build up of fats. Obesity is related to the development of non-transmissible chronic illnesses. Association of rs9939609 polymorphism with the lipidic profile and glycemia were observed. The practicing of physical exercise and feeding habits seem to be the main contributors in the development of overweight/obesity and its resulting co-morbidity

Impact of kinesin Eg5 inhibition by 3,4-dihydropyrimidin-2(1H)-one derivatives on various breast cancer cell features

Background Breast cancer is a complex heterogeneous disease and is one of the leading causes of death among women. In addressing the need for treatments of this life-threatening illness, we studied 3,4-dihydropyrimidin-2(1H)-one (or thione) derivatives (DHPMs), a class of inhibitor molecules of the Eg5 motor spindle protein that shows pronounced antitumor activity against several cancer cell lines. Methods An in vitro screening was performed for identification of DHPMs with potent antitumor effects on MCF-7 and MDA-MB-231 cells and the selected DHPMs were evaluated for their inhibitory activity on Eg5 both in silico, using Molecular dynamics, and in vitro Eg5 inhibition assays. Analysis of cell death induction, proliferation, cell cycle and cancer stem cells (CSC) profile were performed by flow cytometry to assess the influence of the selected DPHMs on these important tumor features. Finally, the effects of DHPM treatment on tube formation were evaluated in vitro using HUVEC cells, and in vivo using a model on chorioallantoic membrane (CAM) of fertilized eggs. Results We identified five DHPMs with pronounced inhibitory activity on Eg5 motor protein interfering with the proper mitotic spindle assembly during cell division. These compounds impair the correct conclusion of cell cycle of the breast cancer cells and showed to be selective for tumor cells. Moreover, DHPMs modulate the CD44[superscript +]/CD24[superscript −] phenotype leading to a decrease in the CSC population in MDA-MB-231 cells, an important effect since CSC are resistant to many conventional cancer therapies and play a pivotal role in tumor initiation and maintenance. This observation was confirmed by the results which demonstrated that DHPM treated cells had impaired proliferation and were unable to sustain angiogenesis events. Finally, the DHMP treated cells were induced to apoptosis, which is one of the most pursued goals in drug development. Conclusions The results of our study strongly suggest that DHPMs inhibit important tumorigenic features of breast cancer cells leading them to death by apoptosis. These findings firmly point to DHPM molecular architecture as a promising alternative against breast cancer

A reduction in CD90 (THY-1) expression results in increased differentiation of mesenchymal stromal cells

Background: Mesenchymal stromal cells (MSCs) are multipotent progenitor cells used in several cell therapies. MSCs are characterized by the expression of CD73, CD90, and CD105 cell markers, and the absence of CD34, CD45, CD11a, CD19, and HLA-DR cell markers. CD90 is a glycoprotein present in the MSC membranes and also in adult cells and cancer stem cells. The role of CD90 in MSCs remains unknown. Here, we sought to analyse the role that CD90 plays in the characteristic properties of in vitro expanded human MSCs. Methods: We investigated the function of CD90 with regard to morphology, proliferation rate, suppression of T-cell proliferation, and osteogenic/adipogenic differentiation of MSCs by reducing the expression of this marker using CD90-target small hairpin RNA lentiviral vectors. Results: The present study shows that a reduction in CD90 expression enhances the osteogenic and adipogenic differentiation of MSCs in vitro and, unexpectedly, causes a decrease in CD44 and CD166 expression. Conclusion: Our study suggests that CD90 controls the differentiation of MSCs by acting as an obstacle in the pathway of differentiation commitment. This may be overcome in the presence of the correct differentiation stimuli, supporting the idea that CD90 level manipulation may lead to more efficient differentiation rates in vitro

Regulation of cell cycle-specific gene expression through cyclin-dependent kinase-mediated phosphorylation of the forkhead transcription factor Fkh2p

The forkhead transcription factor Fkh2p acts in a DNA-bound complex with Mcm1p and the coactivator Ndd1p to regulate cell cycle-dependent expression of the CLB2 gene cluster in Saccharomyces cerevisiae. Here, we demonstrate that Fkh2p is a target of cyclin-dependent protein kinases and that phosphorylation of Fkh2p promotes interactions between Fkh2p and the coactivator Ndd1p. These phosphorylation-dependent changes in the Fkh2p-Ndd1p complex play an important role in the cell cycle-regulated expression of the CLB2 cluster. Our data therefore identify an important regulatory target for cyclin-dependent kinases in the cell cycle and further our molecular understanding of the key cell cycle regulatory transcription factor Fkh2p

Effects of incubation temperature on development, morphology, and thermal physiology of the emerging Neotropical lizard model organism Tropidurus torquatus

Incubation temperature is among the main phenotypic trait variation drivers studied since the developmental trajectory of oviparous animals is directly affected by environmental conditions. In the last decades, global warming predictions have aroused interest in understanding its impacts on biodiversity. It is predicted that the effects of direct warming will be exacerbated by other anthropogenic factors, such as microclimatic edge effects. Although the Brazilian Cerrado biome is one of the most affected by these issues, little is known about the aforementioned effects on its biodiversity. Therefore, the aim of our study is to investigate the influence of incubation temperature on developmental parameters, morphology and thermal physiology traits of the collared lizard (Tropidurus torquatus). Furthermore, we discuss our findings regarding lizard developmental biology and the climate change paradigm. Therefore, we incubated T. torquatus eggs under five temperature regimes ranging from artificial nest temperature (28.7 °C) to 35.0 °C. We found that elevated incubation temperatures affect several investigated traits: egg mass gain is positively affected, without any influence in newborn mass; incubation period is broadly reduced with temperature increase; survival rate is negatively affected by temperature, constant 35.0 °C regime is confirmed as a lethal incubation temperature, and the sex ratio is affected at 30.0 °C, with a prevailing outbreak of females. Increased incubation temperature also affects body and head size but has no effect on limb size. Newborn thermoregulation and the critical thermal maximum (CT max ) are not affected by incubation temperature. On the other hand, basal body temperature (T bb ) and the critical thermal minimum (CT min ) were positively affected. Thermal physiology was also affected by age, with newborns differing from adults for all analyzed thermal traits. Our findings indicate that future modifications in incubation temperature regimes at nesting sites caused by warming may affect several features of the development, morphology, and thermal physiology of newborns of this species. Laboratory experiments have pointed to possible drastic effects of warming on lizard survival rates, also affecting aspects of its natural history and population distribution. Moreover, in addition to being more vulnerable than adults in aspects such as predation and feeding, T. torquatus newborns are also more vulnerable regarding thermal physiological traits.Instituto de Ciências Biológicas (IB)Departamento de Ciências Fisiológicas (IB CFS)Departamento de Ecologia (IB ECL)Departamento de Genética e Morfologia (IB GEM

Genotoxic evaluations in Wistar rats of the hallucinogenic plant extract ayahuasca

Ayahuasca, a psychoactive infusion, is a sacrament used by indigenous and non-indigenous communities in Brazil and other countries. This beverage has vaunted healing properties; however, its use in a therapeutic context still lacks preclinical data to certify its safety and effectiveness. This study evaluated the genotoxic, mutagenic and cytotoxic potential of ayahuasca in Wistar rats after a single oral dose. Rats of both sexes were randomly distributed into five experimental groups (n=10): negative control that received filtered water, positive control that received doxorubicin and treated groups that received ayahuasca at 1, 5 and 15 times the usual dose taken in human religious rituals. The rats were euthanized 30 hours after dosage. Genotoxicity was evaluated by flow cytometry, comet assay and micronucleus test. Renal, hepatic and pancreatic functions were evaluated by serum analysis. Ayahuasca showed low genotoxicity, with an increased frequency of micronuclei only at the highest exposure level, and a non-observed-adverse-effect-level established at 5X the dose, or 1.5 mg/kg bw N,N-dimethyltryptamine a major component of the infusion. No cytotoxic effects were observed in the tested conditions. Furthermore, hepatic, renal and pancreatic functions remained without significant changes for all treated groups.

Reproductive effects of the psychoactive beverage ayahuasca in male Wistar rats after chronic exposure

Ayahuasca is a psychoactive beverage used ancestrally by indigenous Amazonian tribes and, more recently, by Christian religions in Brazil and other countries. This study aimed to investigate the reproductive effects of this beverage in male Wistar rats after chronic exposure. The rats were treated by gavage every other day for 70 days at 0 (control), 1×, 2×, 4× and 8× the dose used in a religious ritual (12 animals per group), and animals euthanized on the 71st day. Compared to controls, there was a significant decrease in food consumption and body weight gain in rats from the 4× and 8× groups, and a significant increase in the brain and stomach relative weight at the 8× group. There was a significant increase in total serum testosterone, and a decrease in spermatic transit time and spermatic reserves in the epididymis caudae in the 4× group, but not in the highest dose group. No significant changes were found in the other reproductive endpoints (spermatozoid motility and morphology, total spermatozoid count and daily sperm production), and histology of testis and epididymis. This study identified a no-observed-adverse-effect-level for chronic and reproductive effects of ayahuasca in male Wistar rats at 2× the ritualistic dose, which corresponds in this study to 0.62 mg/kg bw N, N-dimethyltryptamine, 6.6 mg/kg bw harmine and 0.52 mg/kg bw harmaline. A potential toxic effect of ayahuasca in male rats was observed at the 4× dose, with a non-monotonic dose–response. Studies investigating the role of ayahuasca components in regulating testosterone levels are needed to better understand this action

A Competitive Transcription Factor Binding Mechanism Determines the Timing of Late Cell Cycle-Dependent Gene Expression

Transcriptional control is exerted by the antagonistic activities of activator and repressor proteins. In Saccharomyces cerevisiae, transcription factor complexes containing the MADS box protein Mcm1p are key regulators of cell cycle-dependent transcription at both the G2/M and M/G1 transitions. The homeodomain repressor protein Yox1p acts in a complex with Mcm1p to control the timing of gene expression. Here, we show that Yox1p interacts with Mcm1p through a motif located N terminally to its homeodomain. Yox1p functions as a transcriptional repressor by competing with the forkhead transcription activator protein Fkh2p for binding to Mcm1p through protein-protein interactions at promoters of a subset of Mcm1p-regulated genes. Importantly, this competition is not through binding the same DNA site that is commonly observed. Thus, this study describes a different mechanism for determining the timing of cell cycle-dependent gene expression that involves competition between short peptide motifs in repressor and activator proteins for interaction with a common binding partner