RESUMO

Tumor hypoxia has been associated with cancer progression, angiogenesis, and metastasis via modifications in the release and cargo composition of extracellular vesicles secreted by tumor cells. Indeed, hypoxic extracellular vesicles are known to trigger a variety of angiogenic responses via different mechanisms. We recently showed that hypoxia promotes endosomal signaling in tumor cells via HIF-1α-dependent induction of the guanine exchange factor ALS2, which activates Rab5, leading to downstream events involved in cell migration and invasion. Since Rab5-dependent signaling is required for endothelial cell migration and angiogenesis, we explored the possibility that hypoxia promotes the release of small extracellular vesicles containing ALS2, which in turn activate Rab5 in recipient endothelial cells leading to pro-angiogenic properties. In doing so, we found that hypoxia promoted ALS2 expression and incorporation as cargo within small extracellular vesicles, leading to subsequent transfer to recipient endothelial cells and promoting cell migration, tube formation, and downstream Rab5 activation. Consequently, ALS2-containing small extracellular vesicles increased early endosome size and number in recipient endothelial cells, which was followed by subsequent sequestration of components of the ß-catenin destruction complex within endosomal compartments, leading to stabilization and nuclear localization of ß-catenin. These events converged in the expression of ß-catenin target genes involved in angiogenesis. Knockdown of ALS2 in donor tumor cells precluded its incorporation into small extracellular vesicles, preventing Rab5-downstream events and endothelial cell responses, which depended on Rab5 activity and guanine exchange factor activity of ALS2. These findings indicate that vesicular ALS2, secreted in hypoxia, promotes endothelial cell events leading to angiogenesis. Finally, these events might explain how tumor angiogenesis proceeds in hypoxic conditions.

Assuntos

Assuntos

RESUMO

Fibroblast growth factor 21 (FGF21) is a hormone involved in the regulation of lipid, glucose, and energy metabolism. Although it is released mainly from the liver, in recent years it has been shown that it is a "myokine", synthesized in skeletal muscles after exercise and stress conditions through an Akt-dependent pathway and secreted for mediating autocrine and endocrine roles. To date, the molecular mechanism for the pathophysiological regulation of FGF21 production in skeletal muscle is not totally understood. We have previously demonstrated that muscle membrane depolarization controls gene expression through extracellular ATP (eATP) signaling, by a mechanism defined as "Excitation-Transcription coupling". eATP signaling regulates the expression and secretion of interleukin 6, a well-defined myokine, and activates the Akt/mTOR signaling pathway. This work aimed to study the effect of electrical stimulation in the regulation of both production and secretion of skeletal muscle FGF21, through eATP signaling and PI3K/Akt pathway. Our results show that electrical stimulation increases both mRNA and protein (intracellular and secreted) levels of FGF21, dependent on an extracellular ATP signaling mechanism in skeletal muscle. Using pharmacological inhibitors, we demonstrated that FGF21 production and secretion from muscle requires the activation of the P2YR/PI3K/Akt/mTOR signaling pathway. These results confirm skeletal muscle as a source of FGF21 in physiological conditions and unveil a new molecular mechanism for regulating FGF21 production in this tissue. Our results will allow to identify new molecular targets to understand the regulation of FGF21 both in physiological and pathological conditions, such as exercise, aging, insulin resistance, and Duchenne muscular dystrophy, all characterized by an alteration in both FGF21 levels and ATP signaling components. These data reinforce that eATP signaling is a relevant mechanism for myokine expression in skeletal muscle.

Assuntos

RESUMO

Muscle and bone are tightly integrated through mechanical and biochemical signals. Osteoclasts are cells mostly related to pathological bone loss; however, they also start physiological bone remodeling. Therefore, osteoclast signals released during bone remodeling could improve both bone and skeletal muscle mass. Extracellular ATP is an autocrine/paracrine signaling molecule released by bone and muscle cells. Then, in the present work, it was hypothesized that ATP is a paracrine mediator released by osteoclasts and leads to skeletal muscle protein synthesis. RAW264.7-derived osteoclasts were co-cultured in Transwell® chambers with flexor digitorum brevis (FDB) muscle isolated from adult BalbC mice. The osteoclasts at the upper chamber were mechanically stimulated by controlled culture medium perturbation, resulting in a two-fold increase in protein synthesis in FDB muscle at the lower chamber. Osteoclasts released ATP to the extracellular medium in response to mechanical stimulation, proportional to the magnitude of the stimulus and partly dependent on the P2X7 receptor. On the other hand, exogenous ATP promoted Akt phosphorylation (S473) in isolated FDB muscle in a time- and concentration-dependent manner. ATP also induced phosphorylation of proteins downstream Akt: mTOR (S2448), p70S6K (T389) and 4E-BP1 (T37/46). Exogenous ATP increased the protein synthesis rate in FDB muscle 2.2-fold; this effect was blocked by Suramin (general P2X/P2Y antagonist), LY294002 (phosphatidylinositol 3 kinase inhibitor) and Rapamycin (mTOR inhibitor). These blockers, as well as apyrase (ATP metabolizing enzyme), also abolished the induction of FDB protein synthesis evoked by mechanical stimulation of osteoclasts in the co-culture model. Therefore, the present findings suggest that mechanically stimulated osteoclasts release ATP, leading to protein synthesis in isolated FDB muscle, by activating the P2-PI3K-Akt-mTOR pathway. These results open a new area for research and clinical interest in bone-to-muscle crosstalk in adaptive processes related to muscle use/disuse or in musculoskeletal pathologies.

Assuntos

RESUMO

Background: Natural and intuitive interfaces that monitor and promote upper limb task-specific training need to be developed. This article presents the development and testing of a touch-based game system for training and assessment of unilateral (ULR) and bilateral (BLR) reaching movements. Interaction becomes intuitive and simple by introducing in-game touch and pressure onto virtual targets projected on a custom-made large touch panel. Materials and Methods: A custom-made App integrates exergames and a biomechanical model with advanced algorithms for movement analysis. It processes and manages data from a motion-tracking sensor and a large touch panel equipped with 1222 (26 × 47) piezoresistive sensors, including high-speed readout electronics and algorithms to measure touch points and contact forces during fingertip interaction. An experiment was conducted to evaluate the experience, motivation, and movements of healthy and stroke subjects when interacting with the proposed system. The panel height, dispersion of virtual targets, and required contact force were customized based on motor skills of each group of subjects. Results: Both groups of subjects showed high level of motivation and user experience when interacting with the virtual environments. Stroke subjects performed the task slower and traveled a similar path length than healthy subjects, but with shorter range of motion. The mechanical work and potential energy profiles of both groups are consistent with those achieved when reaching real objects. Conclusions: The proposed contact-based exergames are a feasible solution for performing natural and intuitive therapeutic ULR and BLR exercises. They elicit appropriate reaching movements and contact forces in healthy and stroke subjects. The spatial and temporal attributes of the proposed solution can be customized to influence the movement and energy expenditure of specific joints.

Assuntos

RESUMO

Histatin-1 is a salivary antimicrobial peptide involved in the maintenance of enamel and oral mucosal homeostasis. Moreover, Histatin-1 has been shown to promote re-epithelialization in soft tissues, by stimulating cell adhesion and migration in oral and dermal keratinocytes, gingival and skin fibroblasts, endothelial cells and corneal epithelial cells. The broad-spectrum activity of Histatin-1 suggests that it behaves as a universal wound healing promoter, although this is far from being clear yet. Here, we report that Histatin-1 is a novel osteogenic factor that promotes bone cell adhesion, migration, and differentiation. Specifically, Histatin-1 promoted cell adhesion, spreading, and migration of SAOS-2 cells and MC3T3-E1 preosteoblasts in vitro, when placed on a fibronectin matrix. Besides, Histatin-1 induced the expression of osteogenic genes, including osteocalcin, osteopontin, and Runx2, and increased both activity and protein levels of alkaline phosphatase. Furthermore, Histatin-1 promoted mineralization in vitro, as it augmented the formation of calcium deposits in both SAOS-2 and MC3T3-E1 cells. Mechanistically, although Histatin-1 failed to activate ERK1/2, FAK, and Akt, which are signaling proteins associated with osteogenic differentiation or cell migration, it triggered nuclear relocalization of ß-catenin. Strikingly, the effects of Histatin-1 were recapitulated in cells that are nonosteogenically committed, since it promoted surface adhesion, migration, and the acquisition of osteogenic markers in primary mesenchymal cells derived from the apical papilla and dental pulp. Collectively, these observations indicate that Histatin-1 is a novel osteogenic factor that promotes bone cell differentiation, surface adhesion and migration, as crucial events required for bone tissue regeneration.

Assuntos

RESUMO

We aimed to determine the knowledge and practices regarding toxoplasmosis among housewives in the northern Mexican city of Durango. One hundred eighty-five women (mean age: 41.27 ± 12.40 years old) with an occupation of housewife were studied. A self-administered questionnaire was used. This tool included items about the parasite Toxoplasma gondii, its transmission routes, general clinical, diagnostic, and treatment aspects of toxoplasmosis, and practices to avoid infection. A minority (<10%) of women knew about the parasite, the disease, how the transmission occurs, the clinical manifestations, how an infection is diagnosed, the treatment, and how to avoid toxoplasmosis. Some women knew that cats can transmit T. gondii infection (20%), and that the parasite can be found in cat feces (20.5%). Only 7.6% of women knew that infection with T. gondii can be transmitted by consumption of contaminated food or water. Only 1.1% of women knew about the prevalence of T. gondii infection. Some (4.9%) women used to taste raw meat while cooking, and 7.6% used to undercook meat. In addition, 20% of women used to eat raw dried meat, and 13.5% consumed untreated water. Less than 90% of women always washed their hands before cooking, and washed fruits or vegetables. The majority (75.1%) of women never wore gloves when handling raw meat. About one quarter (27.6%) of women always froze meat. And 16.2% of women cleaned cat feces. This is the first study regarding knowledge and practices about toxoplasmosis in housewives. Poor knowledge regarding T. gondii infection, toxoplasmosis, and practices to avoid infection among the housewives studied was found. High risk practices for infection were identified. Strategies to improve toxoplasmosis-related knowledge and practices to avoid T. gondii infection and its sequelae in housewives are highly needed.

Assuntos

RESUMO

PURPOSE: We aimed to determine the association between Chlamydia trachomatis infection and female sex work, and the association between sociodemographic, obstetric, and behavioral characteristics of female sex workers and C. trachomatis infection. METHODS: Through a case-control study design, we studied 201 female sex workers and 201 age-matched women without sex work in Durango City, Mexico. C. trachomatis DNA was detected in cervical swab samples using polymerase chain reaction. RESULTS: C. trachomatis DNA was detected in 32 (15.9%) of the 201 cases and in 6 (3.0%) of the 201 controls (odds ratio [OR] = 6.15; 95% confidence interval [CI]: 2.5-15.0; P < 0.001). The frequency of infection with C. trachomatis in female sex workers did not vary (P > 0.05) regardless of the history of pregnancies, deliveries, cesarean sections, or miscarriages. Regression analysis of the behavioral characteristics showed that infection with C. trachomatis was associated only with consumption of alcohol (OR = 2.39; 95% CI: 1.0-5.71; P = 0.04). Conclusions: We conclude that C. trachomatis infection is associated with female sex work in Durango City, Mexico. This is the first age-matched case-control study on the prevalence of C. trachomatis infection in female sex workers in Mexico using detection of C. trachomatis DNA in cervical samples.

RESUMO

BACKGROUND: To determine the association of infection with human papillomavirus (HPV) and the occupation of female sex worker; and the correlation of infection with HPV with sociodemographic, clinical and behavioral characteristics of female sex workers. METHODS: We performed a case-control study of 217 female sex workers and 354 women without sex work in Durango City, Mexico. We determined the prevalence of infection with HPV in cervical samples of women using polymerase chain reaction, and HPV genotypes were determined using line probe assay. Bivariate and multivariate analyses were used to assess the association between the characteristics of women and infection. RESULTS: Twelve (5.5%) of the 217 sex workers, and 10 (2.8%) of the 354 control women were positive for HPV DNA (age-adjusted OR = 1.51; 95% CI: 0.62 - 3.68; P = 0.36). Six (50.0%) of the 12 HPV DNA positive sex workers had infections with high-risk genotypes (16, 31, 33, 35, 51, 58). Seven (70%) of the 10 HPV DNA positive control women had infections with high-risk genotypes (16, 18, 56, 58, and 66). The frequency of high risk genotypes in the control women was equal with that found in the female sex workers (P = 0.41). Logistic regression analysis showed that the variable alcohol consumption was associated with HPV infection (OR = 4.0; 95% CI: 1.0 - 16.0; P = 0.04). CONCLUSIONS: No association between HPV infection and female sex work was found in our setting. High risk HPV genotypes were prevalent among the women studied. Results can be used for the design of preventive measures against HPV infection.