Angiotensin Converting Enzyme Regulates Cell Proliferation and Migration

Background The angiotensin-I converting enzyme (ACE) plays a central role in the renin-angiotensin system, acting by converting the hormone angiotensin-I to the active peptide angiotensin-II (Ang-II). More recently, ACE was shown to act as a receptor for Ang-II, and its expression level was demonstrated to be higher in melanoma cells compared to their normal counterparts. However, the function that ACE plays as an Ang-II receptor in melanoma cells has not been defined yet. Aim Therefore, our aim was to examine the role of ACE in tumor cell proliferation and migration. Results We found that upon binding to ACE, Ang-II internalizes with a faster onset compared to the binding of Ang-II to its classical AT1 receptor. We also found that the complex Ang-II/ACE translocates to the nucleus, through a clathrin-mediated process, triggering a transient nuclear Ca2+ signal. In silico studies revealed a possible interaction site between ACE and phospholipase C (PLC), and experimental results in CHO cells, demonstrated that the beta 3 isoform of PLC is the one involved in the Ca2+ signals induced by Ang-II/ACE interaction. Further studies in melanoma cells (TM-5) showed that Ang-II induced cell proliferation through ACE activation, an event that could be inhibited either by ACE inhibitor (Lisinopril) or by the silencing of ACE. In addition, we found that stimulation of ACE by Ang-II caused the melanoma cells to migrate, at least in part due to decreased vinculin expression, a focal adhesion structural protein. Conclusion ACE activation regulates melanoma cell proliferation and migration.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)INCT Nanocarbono - UFMG (Brazil)Univ Fed Minas Gerais, Dept Physiol & Biophys, Belo Horizonte, MG, BrazilUniv Fed Sao Joao del Rei, Dept Nat Sci, Sao Joao Del Rei, MG, BrazilUniv Fed Ceara, Dept Phys, Fortaleza, CE, BrazilUniv Fed Sao Paulo, Dept Biophys, Sao Paulo, SP, BrazilUniv Fed Minas Gerais, Dept Phys, Belo Horizonte, MG, BrazilUniv Fed Minas Gerais, Dept Morphol, Belo Horizonte, MG, BrazilDepartment of Biophysics, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, BrazilWeb of Scienc

Efeitos da ativação da enzima conversora de angiotensina 2 endógena no glaucoma experimental em ratos

Submitted by Caroline Paula ([email protected]) on 2020-02-11T14:42:18Z No. of bitstreams: 1 GiselleFoureauxHeida_TeseDOUTORADO.pdf: 16683907 bytes, checksum: bc51acadcaf972c2317abd5e01260671 (MD5)Approved for entry into archive by Eliane Araujo ([email protected]) on 2020-02-11T14:49:08Z (GMT) No. of bitstreams: 1 GiselleFoureauxHeida_TeseDOUTORADO.pdf: 16683907 bytes, checksum: bc51acadcaf972c2317abd5e01260671 (MD5)Made available in DSpace on 2020-02-17T15:02:58Z (GMT). No. of bitstreams: 1 GiselleFoureauxHeida_TeseDOUTORADO.pdf: 16683907 bytes, checksum: bc51acadcaf972c2317abd5e01260671 (MD5) Previous issue date: 2013-06-10CNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas GeraisCAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorO glaucoma é uma doença neurodegenerativa, geralmente acompanhada de elevação da pressão intra-ocular (PIO), que se caracteriza pela morte progressiva de células ganglionares (CGs) e degeneração do nervo óptico. Vários estudos têm demonstrado a participação do Sistema Renina-Angiotensina (SRA) no glaucoma. Assim, o objetivo deste estudo foi avaliar os efeitos da ativação da ECA2 endógena, utilizando o composto aceturato de diminazeno (DIZE), no glaucoma experimental em ratos Wistar. O glaucoma unilateral foi induzido em ratos (180-220g) através da injeção de 30µL (10mg/mL) de ácido hialurônico na câmara anterior do olho, 1 vez por semana, durante 4, 5 ou 6 semanas. DIZE (1mg/kg) foi administrado diariamente por via sistêmica ou tópica e a PIO foi medida semanalmente utilizando um tonômetro de aplanação. A pressão arterial média (PAM) também foi mensurada semanalmente através da pletismografia de cauda. Para avaliar o papel do receptor Mas nos efeitos do DIZE, o antagonista da Ang-(1-7) A-779 foi administrado através de minibombas osmóticas. Ao final do tratamento, o radioisótopo 99mTc (tecnécio) foi injetado na câmara anterior para avaliar a drenagem do humor aquoso a cada 30 minutos durante 3h. A análise da expressão da ECA2 e das CGs foram realizadas em secções histológicas dos olhos. A ultraestrutura da camada das fibras nervosas foi avaliada por microscopia eletrônica de transmissão. Além disso, foram desenvolvidos dispositivos de liberação controlada, através de inserts de quitosana contendo DIZE, que foram colocados no fórnice conjuntival dos animais. Os resultados mostraram que a administração sistêmica e tópica do DIZE aumentou a expressão da ECA2 na retina. Em relação à PIO, animais com glaucoma que não receberam o tratamento com o DIZE (grupo GNT) apresentaram valores significativamente maiores (27,1 ± 1,9 mmHg) quando comparado com ratos normais (9,0 ± 2,7 mmHg). Tanto a administração sistêmica quanto a tópica normalizou a PIO (instilação: 9,6 ± 1,1 mmHg) sem mudanças significativas na PAM. Estes efeitos foram completamente bloqueadas pelo A-779. A análise histológica revelou que a redução no número de CGs e apoptose observadas no grupo GNT (540,9 ± 9,3 células) foi prevenida pela ativação da ECA2 (629,0 ± 8,8 células). Além de promover neuroproteção, o DIZE também foi capaz de facilitar a drenagem do humor aquoso. Os dispositivos de liberação controlada foram bem tolerados pelos animais e foram eficientes em reduzir a PIO por 30 dias com uma dose similar àquela usada em um único dia no tratamento tópico. Assim, nossos resultados indicam a importância patofisiológica do eixo ECA2/Ang-(1-7)/Mas do SRA ocular de ratos e, mais importante, indicam que a ativação da ECA2 endógena é uma estratégia terapêutica potencial para o tratamento do glaucoma.The purpose of this study was to evaluate the effects of the activation of endogenous angiotensin-converting enzyme 2 (ACE2) using the compound diminazene aceturate (DIZE) in an experimental model of glaucoma in Wistar rats. DIZE (1mg/kg) was administered daily either systemically or topically, and the intraocular pressure (IOP) was measured weekly. To examine the role of the Mas receptor in the effects of DIZE, the Ang-(1-7) antagonist A-779 was coadministered. Drainage of the aqueous humor was evaluated by using scintigraphy. The analysis of ACE2 expression by immunohistochemistry and the counting of retinal ganglion cells (RGCs) were performed in histological sections. Additionally, the nerve fiber structure was evaluated by transmission electron microscopy. In addition, chitosan films containing DIZE were developed for controlled release of the compound and placed in the conjunctival fornix of the animals. The systemic and topical administration (in the form of eye drops) of DIZE increased the ACE2 expression in the eyes and significantly decreased the IOP of glaucomatous rats without changing the blood pressure. Importantly, this IOP-lowering action of DIZE was similar to the effects of dorzolamide. The antiglaucomatous effects of DIZE were blocked by A-779. Histological analysis revealed that the reduction in the number of RGCs and the increase in the expression of caspase-3 in the RGC layer in glaucomatous animals were prevented by DIZE. This compound also prevented alterations in the cytoplasm of axons in glaucomatous rats. In addition to these possible neuroprotective effects, DIZE facilitated the drainage of the aqueous humor. Chitosan films containing DIZE were well tolerated by the animals and were effective in reducing IOP for 30 days utilizing the amount of the compound used in a single dose of the topical treatment. Our results evidence the pathophysiological relevance of the ocular ACE2/Ang-(1-7)/Mas axis of the renin-angiotensin system and, importantly, indicate that the activation of intrinsic ACE2 is a potential therapeutic strategy to treat glaucom

O ensino-aprendizagem da anatomia humana: avaliação do desempenho dos alunos após a utilização de mapas conceituais como uma estratégia pedagógica

Abstract The aim of this study was to implement and evaluate the impact of the development of Concept Maps (MC), as a pedagogical strategy in teaching of Human Anatomy, one of the course subjects of Physical Therapy, from Federal University of Minas Gerais (UFMG). A total of 298 students, enrolled regularly, participated of the study over six semesters. The mean analysis of the final scores of the students, prior to the expansion of the MC Project, showed decrease of average score over the semester, which was reversed when the MC were implemented systematically. The implementation of MC were also capable of promoting a significant reduction in the failure rate. Thus, we conclude that the use of MC seems to have contributed to improving student performance and also the approval rating in the discipline of Anatomy, especially after the systematization of its use by the Teaching Project supported by the institution.Resumo O objetivo deste estudo foi implementar e avaliar o impacto da elaboração de Mapas Conceituais (MC) como estratégia pedagógica no ensino-aprendizagem da Anatomia Humana, uma das disciplinas do curso de Fisioterapia da Universidade Federal de Minas Gerais. Participaram do estudo 298 alunos regularmente matriculados, ao longo de seis semestres. A análise das médias das notas finais dos alunos, anteriores à ampliação do projeto dos MC, demonstrou decréscimo dessas médias ao longo dos semestres, o que foi revertido quando o projeto de ensino de MC foi implementado sistematicamente. A implementação dos MC também foi capaz de promover uma redução significativa no índice de reprovação. Assim, concluímos que o uso de MC parece ter contribuído para melhorar o desempenho dos alunos e também o índice de aprovação na disciplina de Anatomia Humana, principalmente após a sistematização do seu uso através do Projeto de Ensino apoiado pela Pró-Reitoria de Graduação da Instituição

O ensino-aprendizagem da anatomia humana: avaliação do desempenho dos alunos após a utilização de mapas conceituais como uma estratégia pedagógica

Resumo O objetivo deste estudo foi implementar e avaliar o impacto da elaboração de Mapas Conceituais (MC) como estratégia pedagógica no ensino-aprendizagem da Anatomia Humana, uma das disciplinas do curso de Fisioterapia da Universidade Federal de Minas Gerais. Participaram do estudo 298 alunos regularmente matriculados, ao longo de seis semestres. A análise das médias das notas finais dos alunos, anteriores à ampliação do projeto dos MC, demonstrou decréscimo dessas médias ao longo dos semestres, o que foi revertido quando o projeto de ensino de MC foi implementado sistematicamente. A implementação dos MC também foi capaz de promover uma redução significativa no índice de reprovação. Assim, concluímos que o uso de MC parece ter contribuído para melhorar o desempenho dos alunos e também o índice de aprovação na disciplina de Anatomia Humana, principalmente após a sistematização do seu uso através do Projeto de Ensino apoiado pela Pró-Reitoria de Graduação da Instituição

The angiotensin-(1-7)/Mas receptor axis is expressed in sinoatrial node cells of rats.

The authors’ previous studies have indicated that angiotensin(Ang)-(1-7) protects the heart against reperfusion arrhythmias. The aim of this study was to determine whether a functional angiotensin-converting enzyme2 (ACE2)/Ang-(1-7)/Mas receptor axis is present in the sinoatrial node (SAN) of Wistar rats. SAN cells were identified by Masson’s trichrome staining, HCN4 expression, and lack of connexin43 expression. Immunohistochemistry technique was used to detect the expression of ACE2, Ang-(1-7), and Mas in the SAN. To evaluate the role of this axis in the SAN function, atrial tachyarrhythmias (ATs) were induced in isolated rat atria perfused with Krebs-Ringer solution (KRS) alone (control) or KRS containing Ang-(1-7). The specific Mas antagonist, A-779, was used to evaluate the role of Mas in the Ang-(1-7) effects. The findings showed that all components of the ACE2/Ang-(1-7)/Mas branch are present in the SAN of rats. Importantly, it was found that this axis is functional because perfusion of atria with Ang-(1-7) significantly reduced the duration of ATs. Additionally, this anti-arrhythmogenic effect was attenuated by A-779. No significant changes were observed in heart rate, contractile tension, or ±dT/dt. These observations demonstrate that the ACE2/Ang-(1-7)/Mas axis is expressed in SAN cells of rats. They provide the morphological support to the anti-arrhythmogenic effect of Ang-(1-7). (J Histochem Cytochem 59:761–768, 2011)

The teaching and learning of human anatomy: the assessment of student performance after the use of concept maps as a pedagogical strategy

<p></p><p>Abstract The aim of this study was to implement and evaluate the impact of the development of Concept Maps (MC), as a pedagogical strategy in teaching of Human Anatomy, one of the course subjects of Physical Therapy, from Federal University of Minas Gerais (UFMG). A total of 298 students, enrolled regularly, participated of the study over six semesters. The mean analysis of the final scores of the students, prior to the expansion of the MC Project, showed decrease of average score over the semester, which was reversed when the MC were implemented systematically. The implementation of MC were also capable of promoting a significant reduction in the failure rate. Thus, we conclude that the use of MC seems to have contributed to improving student performance and also the approval rating in the discipline of Anatomy, especially after the systematization of its use by the Teaching Project supported by the institution.</p><p></p

Bimatoprost-loaded ocular inserts as sustained release drug delivery systems for glaucoma treatment: in vitro and in vivo evaluation.

The purpose of the present study was to develop and assess a novel sustained-release drug delivery system of Bimatoprost (BIM). Chitosan polymeric inserts were prepared using the solvent casting method and characterized by swelling studies, infrared spectroscopy, differential scanning calorimetry, drug content, scanning electron microscopy and in vitro drug release. Biodistribution of 99mTc-BIM eye drops and 99mTc-BIM-loaded inserts, after ocular administration in Wistar rats, was accessed by ex vivo radiation counting. The inserts were evaluated for their therapeutic efficacy in glaucomatous Wistar rats. Glaucoma was induced by weekly intracameral injection of hyaluronic acid. BIM-loaded inserts (equivalent to 9.0 µg BIM) were administered once into conjunctival sac, after ocular hypertension confirmation. BIM eye drop was topically instilled in a second group of glaucomatous rats for 15 days days, while placebo inserts were administered once in a third group. An untreated glaucomatous group was used as control. Intraocular pressure (IOP) was monitored for four consecutive weeks after treatment began. At the end of the experiment, retinal ganglion cells and optic nerve head cupping were evaluated in the histological eye sections. Characterization results revealed that the drug physically interacted, but did not chemically react with the polymeric matrix. Inserts sustainedly released BIM in vitro during 8 hours. Biodistribution studies showed that the amount of 99mTc-BIM that remained in the eye was significantly lower after eye drop instillation than after chitosan insert implantation. BIM-loaded inserts lowered IOP for 4 weeks, after one application, while IOP values remained significantly high for the placebo and untreated groups. Eye drops were only effective during the daily treatment period. IOP results were reflected in RGC counting and optic nerve head cupping damage. BIM-loaded inserts provided sustained release of BIM and seem to be a promising system for glaucoma management