Rita Nogueira-Ferreira

Exploring the monocrotaline animal model for the study of pulmonary arterial hypertension: A network approach.

Pulmonary arterial hypertension (PAH) is responsible for the premature death mainly because of progressive and severe heart failure. This disease is characterized by increased pulmonary vascular tone, inflammatory cell infiltration, vascular remodeling and occlusion of vessels with thrombi, frequently leading to right heart failure. Aiming to better comprehend the complexity of PAH and find novel therapeutic strategies or improve the existing ones, a variety of preclinical models have emerged. Although there is no ideal preclinical model of PAH currently available, animal models have been used to assist in the identification of the molecular pathways underlying PAH development and progression, and in the identification of novel therapeutics. Among preclinical models of PAH, monocrotaline (MCT) animal model offers the advantage of mimic several key aspects of human PAH, including vascular remodeling, proliferation of smooth muscle cells, endothelial dysfunction, upregulation of inflammatory cytokines, and right ventricle failure, requiring a single drug injection. This review summarizes the advantages and limitations of MCT animal model to the study of the molecular mechanisms underlying PAH pathogenesis, envisioning to improve the diagnosis and management of this complex disease.

Exploring the role of post-translational modifications on protein-protein interactions with survivin.

Survivin is a member of the inhibitor of apoptosis protein (IAP) family with crucial roles in apoptosis and cell cycle regulation. Post-translational modifications (PTMs) have a ubiquitous role in the regulation of a diverse range of proteins cellular functions and survivin is not an exception. Phosphorylation, acetylation and ubiquitination seem to regulate survivin anti-apoptotic and mitotic roles and also its nuclear localization. In the present review we explore the role of PTMs on protein-protein interactions focused on survivin to provide new insights into the functions and cell localization of this IAP in pathophysiological conditions, which might help the envisioning of novel targeted therapies for diseases characterized by impaired survivin activity. Protein-protein interaction analysis was performed with bioinformatics tools based on published data aiming to give an integrated perspective of this IAPs role in the cell.

Cellular interplay in pulmonary arterial hypertension: Implications for new therapies

Pulmonary arterial hypertension (PAH) is a complex and multifactorial disease characterized by vascular remodeling, vasoconstriction, inflammation and thrombosis. Although the available therapies have resulted in improvements in morbidity and survival, PAH remains a severe and devastating disease with a poor prognosis and a high mortality, justifying the need of novel therapeutic targets. An increasing number of studies have demonstrated that endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblasts of the pulmonary vessel wall, as well as platelets and inflammatory cells have a role in PAH pathogenesis. This review aims to integrate the interplay among different types of cells, during PAH development and progression, and the impact of current therapies in cellular modulation. The interplay among endothelial cells, smooth muscle cells and fibroblasts present in pulmonary vessels wall, platelets and inflammatory cells is regulated by several mediators produced by these cells, contributing to the pathophysiologic features of PAH. Current therapies are mainly focused in the pulmonary vascular tone and in the endothelial dysfunction. However, once they have not been effective, novel therapies targeting other PAH features, such as inflammation and platelet dysfunction are emerging. Further understanding of the interplay among different vascular cell types involved in PAH development and progression can contribute to find novel therapeutic targets, decreasing PAH mortality and morbidity in the future.

HPV16 induces a wasting syndrome in transgenic mice: Amelioration by dietary polyphenols via NF-κB inhibition

&NA; Cancer patients often show a wasting syndrome for which there are little therapeutic options. Dietary polyphenols have been proposed for treating this syndrome, but their usefulness in cases associated with human papillomavirus (HPV)‐induced cancers is unknown. We characterized HPV16‐transgenic mice as a model of cancer cachexia and tested the efficacy of long‐term oral supplementation with polyphenols curcumin and rutin. Both compounds were orally administered to six weeks‐old HPV16‐transgenic mice showing characteristic multi‐step skin carcinogenesis, for 24 weeks. Skin lesions and blood, liver and spleen inflammatory changes were characterized histologically and hematologically. Hepatic oxidative stress, skeletal muscle mass and the levels of muscle pro‐inflammatory transcription factor NF‐&kgr;B were also assessed. Skin carcinogenesis was associated with progressive, severe, systemic inflammation (leukocytosis, hepatitis, splenitis), significant mortality and cachexia. Curcumin and rutin totally suppressed mortality while reducing white blood cells and the incidence of splenitis and hepatitis. Rutin prevented muscle wasting more effectively than curcumin. Preservation of muscle mass and reduced hepatic inflammation were associated with down‐regulation of the NF‐&kgr;B canonical pathway and with reduced oxidative stress, respectively. These results point out HPV16‐transgenic mice as a useful model for studying the wasting syndrome associated with HPV‐induced cancers. Dietary NF‐&kgr;B inhibitors may be useful resources for treating this syndrome.

Anti-tumoral activity of human salivary peptides

Chemotherapy continues to be the standard treatment for advanced or metastasized cancer. However, commonly used chemotherapeutic agents may induce damage in healthy cells and tissues. Thus, in recent years, there has been an increased focus on the development of new, efficient anticancer drugs exhibiting low toxicity and that are not affected by mechanisms of chemoresistance. In the present work, we tested synthetic and naturally obtained human salivary peptides against breast, prostate, colon, osteosarcoma and bladder cancer cell lines (T47-D, PC-3, HT-29, MG63, T-24, respectively). Results have showed that there is a reduced cell population increase that is peptide-, cell- and possibly pathway-specific, with the most potent effect observed in observed in T-47D breast cancer cells. Protein expression and microscopy results further indicate that, in this cell line, the peptide with the sequence GPPPQGGRPQG (GG peptide) interferes with the ability of cell adhesion proteins to stabilize adherens junctions, such as E-cadherin, leading to apoptosis. These promising results encourage future works aimed at disclosing the vast potential of salivary peptides as new therapeutic agents.

Exercise preconditioning prevents MCT-induced right ventricle remodeling through the regulation of TNF superfamily cytokines.

BACKGROUNDnExercise training has been recognized as a non-pharmacological therapeutic approach in several chronic diseases; however it remains to be tested if exercise preconditioning can positively interfere with the natural history of pulmonary arterial hypertension (PAH). This is important since the majority of these patients are diagnosed at advanced stages of the disease, when right ventricle (RV) impairment is already present.nnnOBJECTIVESnIn the current study, we evaluated the preventive effect of exercise preconditioning on RV failure secondary to PAH, with a focus on the signaling pathways modulated by pro-inflammatory cytokines from TNF superfamily.nnnMETHODSnWe analyzed the RV muscle from adult male Wistar rats exposed to a 4-week treadmill exercise training or sedentary regime, prior to the administration of monocrotaline (MCT) to induce PAH or with saline solution (controls).nnnRESULTSnData indicate that exercise preconditioning prevented cardiac hypertrophy and RV diastolic dysfunction. At a molecular level, exercise modulated the TWEAK/NF-κB signaling axis and prevented the shift in MHC isoforms towards an increased expression of beta-MHC. Exercise preconditioning also prevented the increase of atrogin-1 expression, and induced a shift of MMP activity from MMP-9 to MMP-2 activity.nnnCONCLUSIONSnAltogether, data support exercise as a preventive strategy for the management of PAH, which is of particular relevance for the familial form of PAH that is manifested by greater severity or earlier onset.

Exercise training protects against cancer-induced cardiac remodeling in an animal model of urothelial carcinoma

Limiting cancer-induced cardiac damage has become an increasingly important issue to improve survival rates and quality of life. Exercise training has been shown to reduce cardiovascular complications in several diseases; however, its therapeutic role against cardiovascular consequences of cancer is in its infancy. In order to add new insights on the potential therapeutic effect of exercise training on cancer-related cardiac dysfunction, we used an animal model of urothelial carcinoma submitted to 13 weeks of treadmill exercise after 20 weeks of exposure to the carcinogenic N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN). Data showed that 13 weeks of treadmill exercise reverted cancer-induced cardiomyocytes atrophy and fibrosis, improved cardiac oxidative capacity given by citrate synthase activity and MnSOD content, and increased the levels of the mitochondrial biogenesis markers PGC-1α and mtTFA. Moreover, exercise training reverted cancer-induced decrease of cardiac c-kit levels suggesting enhanced regenerative ability of heart. These cardiac adaptations to exercise were related to a lower incidence of malignant urothelial lesions and less signs of inflammation. Taken together, data from the present study support the beneficial effect of exercise training when started after cancer diagnosis, envisioning the improvement of the cardiovascular function.

HMGB1 Down-Regulation Mediates Terameprocol Vascular Anti-Proliferative Effect in Experimental Pulmonary Hypertension.

Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis. Pulmonary artery smooth muscle cells (PASMCs) play a crucial role in PAH pathophysiology, displaying a hyperproliferative, and apoptotic‐resistant phenotype. In the present study, we evaluated the potential therapeutic role of terameprocol (TMP), an inhibitor of cellular proliferation and promoter of apoptosis, in a well‐established pre‐clinical model of PAH induced by monocrotaline (MCT) and studied the biological pathways modulated by TMP in PASMCs. Wistar rats injected with MCT or saline (SHAM group) were treated with TMP or vehicle. On day 21 after injection, we assessed bi‐ventricular hemodynamics and cardiac and pulmonary morphometry. The effects of TMP on PASMCs were studied in a primary culture isolated from SHAM and MCT‐treated rats, using an iTRAQ‐based proteomic approach to investigate the molecular pathways modulated by this drug. In vivo, TMP significantly reduced pulmonary and cardiac remodeling and improved cardiac function in PAH. In vitro, TMP inhibited proliferation and induced apoptosis of PASMCs. A total of 65 proteins were differentially expressed in PASMCs from MCT rats treated with TMP, some of which involved in the modulation of transforming growth factor beta pathway and DNA transcription. Anti‐proliferative effect of TMP seems to be explained, at least in part, by the down‐regulation of the transcription factor HMGB1. Our findings support the beneficial role of TMP in PAH and suggest that it may be an effective therapeutic option to be considered in the clinical management of PAH.

Signaling pathways underlying skeletal muscle wasting in experimental pulmonary arterial hypertension.

Abstract Background Skeletal muscle wasting contributes to the poor functional status and quality of life of patients with pulmonary arterial hypertension (PAH). The present study aims to characterize the molecular mechanism underlying skeletal muscle wasting in experimental PAH induced by monocrotaline (MCT). Methods Male Wistar rats were randomly injected with saline solution (CONT; nxa0=xa010) or MCT (MCT; 60xa0mg/kg, s.c.; nxa0=xa015). After 4xa0weeks of MCT or vehicle administration, animals were anesthetized and submitted to right ventricular (RV) hemodynamic evaluation. Blood and gastrocnemius sample s were collected and stored for analysis. Results MCT group developed PAH (70% increase in RV peak systolic pressure) RV dysfunction (increased end-diastolic pressure and Tau), and body and muscle wasting (reduction of 20%, 16% and 30% on body weight, gastrocnemius mass and fiber cross sectional area, respectively). Muscle atrophy was associated with a decrease in type I MHC. Circulating (C reactive protein, myostatin and IL-1beta) and local catabolic markers (MAFbx/atrogin-1, protease activity) were increased in MCT animals, while Akt/mTOR pathway was preserved. Mitochondria isolated from gastrocnemius of MCT animals showed decreased activity of ATP synthase, lower levels of Tfam, accumulation of oxidatively modified proteins together with reduced levels of paraplegin. Conclusions Our data suggests an anabolic/catabolic imbalance in gastrocnemius from MCT-induced PAH rats. Accumulation of dysfunctional mitochondria due to the inefficiency of protein quality control systems to eliminate damaged proteins could also contribute to muscle atrophy in PAH.

Mechanisms underlying the impact of exercise training in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by progressive increases in pulmonary vascular resistance that can ultimately lead to right ventricle failure and death. Common symptoms include shortness of breath, fatigue, dizziness and chest pain, which negatively impact the functional capacity and quality of life. Despite the improvements in disease-targeted therapies, PAH remains incurable and with a high mortality rate, requiring effective therapeutic strategies. Exercise training is an important adjunct non-pharmacological treatment for patients with left heart failure and chronic obstructive pulmonary disease. Although exercise training was discouraged in PAH because of safety concerns, recent studies support that supervised exercise training is safe and beneficial in patients with stable PAH. However, the molecular mechanisms underlying these improvements are still poorly understood. This review summarizes and integrates the emerging clinical and experimental studies describing the molecular alterations related with exercise training in PAH.