RESUMEN
In recent years, proteasome involvement in the damage response induced by ionizing radiation (IR) became evident. However, whether proteasome plays a direct or indirect role in IR-induced damage response still unclear. Trypanosoma cruzi is a human parasite capable of remarkable high tolerance to IR, suggesting a highly efficient damage response system. Here, we investigate the role of T. cruzi proteasome in the damage response induced by IR. We exposed epimastigotes to high doses of gamma ray and we analyzed the expression and subcellular localization of several components of the ubiquitin-proteasome system. We show that proteasome inhibition increases IR-induced cell growth arrest and proteasome-mediated proteolysis is altered after parasite exposure. We observed nuclear accumulation of 19S and 20S proteasome subunits in response to IR treatments. Intriguingly, the dynamic of 19S particle nuclear accumulation was more similar to the dynamic observed for Rad51 nuclear translocation than the observed for 20S. In the other hand, 20S increase and nuclear translocation could be related with an increase of its regulator PA26 and high levels of proteasome-mediated proteolysis in vitro. The intersection between the opposed peaks of 19S and 20S protein levels was marked by nuclear accumulation of both 20S and 19S together with Ubiquitin, suggesting a role of ubiquitin-proteasome system in the nuclear protein turnover at the time. Our results revealed the importance of proteasome-mediated proteolysis in T. cruzi IR-induced damage response suggesting that proteasome is also involved in T. cruzi IR tolerance. Moreover, our data support the possible direct/signaling role of 19S in DNA damage repair. Based on these results, we speculate that spatial and temporal differences between the 19S particle and 20S proteasome controls proteasome multiple roles in IR damage response.
Asunto(s)
Complejo de la Endopetidasa Proteasomal/metabolismo , Radiación Ionizante , Trypanosoma cruzi/metabolismo , Trypanosoma cruzi/efectos de la radiación , Ubiquitina/metabolismo , Reparación del ADN , Proteolisis , Respuesta de Proteína DesplegadaRESUMEN
PURPOSE OF REVIEW: In this article, we review the recent findings regarding a new derivative of angiotensin-(1-7) [Ang-(1-7)], alamandine, and its receptor, the Mas-related G-coupled receptor type D (MrgD) with a special emphasis on its role and how it can be formed. RECENT FINDINGS: Over the last decade, there have been significant conceptual changes regarding the understanding of the renin-angiotensin system (RAS). A cardioprotective axis has been elucidated by the discovery of the Mas receptor for the biologically active Ang-(1-7), and the angiotensin-converting enzyme 2 (ACE2) that coverts Ang II into Ang-(1-7). In addition, several components of the system, such as Ang-(1-12), Angiotensin A (Ang A) and the newly discovered peptide, alamandine, have been identified. Alamandine is generated by catalysis of Ang A via ACE2 or directly from Ang-(1-7). SUMMARY: Alamandine is a vasoactive peptide with similar protective actions as Ang-(1-7) that acts through the MrgD and may represent another important counter-regulatory mechanism within the RAS.
Asunto(s)
Oligopéptidos/metabolismo , Sistema Renina-Angiotensina , Angiotensina I/metabolismo , Enzima Convertidora de Angiotensina 2 , Angiotensinas/metabolismo , Animales , Humanos , Fragmentos de Péptidos/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Transducción de SeñalRESUMEN
It is well known that the RAS (renin-angiotensin system) plays a key role in the modulation of many functions in the body. AngII (angiotensin II) acting on AT1R (type 1 AngII receptor) has a central role in mediating most of the actions of the RAS. However, over the past 10 years, several studies have presented evidence for the existence of a new arm of the RAS, namely the ACE (angiotensin-converting enzyme) 2/Ang-(1-7) [angiotensin-(1-7)]/Mas axis. Ang-(1-7) can be produced from AngI or AngII via endo- or carboxy-peptidases respectively. ACE2 appears to play a central role in Ang-(1-7) formation. As described for AngII, Ang-(1-7) also has a broad range of effects in different organs and tissues which goes beyond its initially described cardiovascular and renal actions. Those effects are mediated by Mas and can counter-regulate most of the deleterious effects of AngII. The interaction Ang-(1-7)/Mas regulates different signalling pathways, such as PI3K (phosphoinositide 3-kinase)/AKT and ERK (extracellularsignal-regulated kinase) pathways and involves downstream effectors such as NO, FOXO1 (forkhead box O1) and COX-2 (cyclo-oxygenase-2). Through these mechanisms, Ang-(1-7) is able to improve pathological conditions including fibrosis and inflammation in organs such as lungs, liver and kidney. In addition, this heptapeptide has positive effects on metabolism, increasing the glucose uptake and lipolysis while decreasing insulin resistance and dyslipidaemia. Ang-(1-7) is also able to improve cerebroprotection against ischaemic stroke, besides its effects on learning and memory. The reproductive system can also be affected by Ang-(1-7) treatment, with enhanced ovulation, spermatogenesis and sexual steroids synthesis. Finally, Ang-(1-7) is considered a potential anti-cancer treatment since it is able to inhibit cell proliferation and angiogenesis. Thus the ACE2/Ang-(1-7)/Mas pathway seems to be involved in many physiological and pathophysiological processes in several systems and organs especially by opposing the detrimental effects of inappropriate overactivation of the ACE/AngII/AT1R axis.
Asunto(s)
Angiotensina I/fisiología , Angiotensina I/uso terapéutico , Fragmentos de Péptidos/fisiología , Fragmentos de Péptidos/uso terapéutico , Peptidil-Dipeptidasa A/metabolismo , Proteínas Proto-Oncogénicas/fisiología , Receptores Acoplados a Proteínas G/fisiología , Inhibidores de la Angiogénesis/farmacología , Animales , Antiinflamatorios/farmacología , Antineoplásicos/farmacología , Isquemia Encefálica/prevención & control , Proliferación Celular/efectos de los fármacos , Femenino , Fibrosis/prevención & control , Glucosa/metabolismo , Humanos , Insulina/metabolismo , Riñón/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Síndrome Metabólico/prevención & control , Proto-Oncogenes Mas , Sistema Renina-Angiotensina/efectos de los fármacos , Sistema Renina-Angiotensina/fisiología , Reproducción/efectos de los fármacos , Transducción de Señal/fisiologíaRESUMEN
Paracoccidioides brasiliensis is the etiologic agent of the Paracoccidioidomycosis the most common systemic mycosis in Latin America. Little is known about the regulation of genes involved in the innate immune host response to P. brasiliensis. We therefore examined the kinetic profile of gene expression of peritoneal macrophage infected with P. brasiliensis. Total RNA from macrophages at 6, 24 and 48h was extracted, hybridized onto nylon membranes and analyzed. An increase in the transcription of a number of pro-inflammatory molecules encoding membrane proteins, metalloproteases, involved in adhesion and phagocytosis, are described. We observed also the differential expression of genes whose products may cause apoptotic events induced at 24h. In addition, considering the simultaneous analyses of differential gene expression for the pathogen reported before by our group, at six hours post infection, we propose a model at molecular level for the P. brasiliensis-macrophage early interaction. In this regard, P. brasiliensis regulates genes specially related to stress and macrophages, at the same time point, up-regulate genes related to inflammation and phagocytosis, probably as an effort to counteract infection by the fungus.
Asunto(s)
Perfilación de la Expresión Génica , Macrófagos Peritoneales/microbiología , Paracoccidioides/inmunología , Animales , Apoptosis , Células Cultivadas , Inflamación/genética , Inflamación/inmunología , Mediadores de Inflamación/metabolismo , Ratones , Modelos Biológicos , Fagocitosis , Factores de Tiempo , Regulación hacia ArribaRESUMEN
Paracoccidioides brasiliensis, a thermal dimorphic fungus, is the etiologic agent of the most common systemic mycosis in Latin America, paracoccidioidomycosis. The yeast form of P. brasiliensis acts as a facultative intracellular pathogen being able to survive and replicate within the phagosome of nonactivated murine and human macrophages. This ability has been proposed to be crucial to the development of disease. Thus, P. brasiliensis may have evolved mechanisms that counteract the constraints imposed by phagocytic cells. By using cDNA microarray technology we evaluated the early transcriptional response of this fungus to the environment of peritoneal murine macrophages in order to shed light on the mechanisms used by P. brasiliensis to survive within phagocytic cells. Of the 1152 genes analyzed, we identified 152 genes that were differentially transcribed. Intracellularly expressed genes were primarily associated with glucose and amino acid limitation, cell wall construction, and oxidative stress. For the first time, a comprehensive gene expression tool is used for the expression analysis of P. brasiliensis genes when interacting with macrophages. Overall, our data show a transcriptional plasticity of P. brasiliensis in response to the harsh environment of macrophages which may lead to adaptation and consequent survival of this pathogen.