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The small GTPase RhoA and the downstream Rho kinase (ROCK) regulate several cell functions and pathological processes in the vascular system that contribute to the age-dependent risk of cardiovascular disease, including endothelial dysfunction, excessive permeability, inflammation, impaired angiogenesis, abnormal vasoconstriction, decreased nitric oxide production and apoptosis. Frailty is a loss of physiological reserve and adaptive capacity with advanced age and is accompanied by a pro-inflammatory and pro-oxidative state that promotes vascular dysfunction and thrombosis. This review summarises the role of the RhoA/Rho kinase signalling pathway in endothelial dysfunction, the acquisition of the pro-thrombotic state and vascular ageing. We also discuss the possible role of RhoA/Rho kinase signalling as a promising therapeutic target for the prevention and treatment of age-related cardiovascular disease.

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Infecções por Plasmodium sp. podem levar a um quadro respiratório grave, com complicações pulmonares denominadas lesão pulmonar aguda e síndrome do desconforto respiratório agudo (LPA/SDRA). Inflamação aguda, lesão do endotélio alveolar e do parênquima pulmonar, disfunção e aumento da permeabilidade da barreira alvéolo-capilar e, consequente, formação de edema, caracterizam esta síndrome. O modelo experimental, que utiliza o parasita murino Plasmodium berghei ANKA e camundongos da linhagem DBA/2, é empregado no estudo de mediadores imunológicos e fatores que propiciam o estabelecimento das lesões pulmonares associados à LPA/SDRA. Diversos estímulos podem atuar diretamente no aumento da permeabilidade endotelial por meio da desestabilização dos microtúbulos, rearranjo dos microfilamentos de actina e contração das células endoteliais, via sinalização de Rho-GTPases, causando disfunção da barreira endotelial. Desta forma, este trabalho tem como objetivo avaliar as alterações do citoesqueleto em células endoteliais primárias pulmonares de camundongos DBA/2 (CEPP-DBA/2), as vias de sinalização das principais Rho-GTPases e o estresse oxidativo, causados pela presença de eritrócitos parasitados com esquizontes de P. berghei ANKA (EP-PbA). As CEPP-DBA/2 foram estimuladas com TNF, VEGF ou IFNγ, em diferentes tempos de exposição, seguido da incubação com EP-PbA. Assim, foram realizados ensaios de imunofluorescência para análise do rearranjo de microfilamentos de actina e da desestabilização de microtúbulos. As vias de sinalização das Rho-GTPases foram avaliadas por Western blot, para as expressões proteicas de RhoA, Cdc42 e MLC. Além disso, ensaio fluorométrico foi realizado para detectar a produção de espécies reativas de oxigênio, resultantes do estímulo com eritrócitos parasitados. CEPP-DBA/2 estimuladas por EP-PbA, VEGF, TNF ou IFNγ, em associação ou não, apresentaram alterações morfológicas nos microfilamentos de actina e aumento dos espaços interendoteliais. Imagens de imunofluorescência também mostram desestabilização de microtúbulos e desfosforilação de FAK, causadas por EP-PbA. Os ensaios de permeabilidade validam que os eritrócitos parasitados com formas maduras de P. berghei induziram aumento da permeabilidade microvascular nas CEPP-DBA/2. Além disso, estas células, estimuladas com EP-PbA, demonstraram elevada produção de espécies reativas de oxigênio (EROs), o que pode estar contribuindo com o desenvolvimento de estresse oxidativo e com a injúria endotelial, assim como, com o aumento da permeabilidade vascular. O mais interessante é que estas alterações endoteliais podem estar relacionadas ao aumento da razão RhoA/Cdc42, da expressão proteica de MLC fosforilada e do sinal de ativação de RhoA. Em conjunto, estes resultados mostram envolvimento dos eritrócitos parasitados com esquizontes de Plasmodium berghei ANKA na desorganização do citoesqueleto e na disfunção da barreira alvéolo-capilar, via RhoA/Rho-kinase, o que pode estar contribuindo com a patogênese da LPA/SDRA associada à malária

Infections by Plasmodium sp. can lead to a serious respiratory condition with pulmonary complications, named acute lung injury and acute respiratory distress syndrome (ALI/ARDS). Acute inflammation, alveolar endothelium and lung parenchyma injuries, dysfunction and increased permeability of the pulmonary alveolar-capillary barrier and consequent formation of edema characterize this syndrome. Several stimuli can directly increase endothelial permeability through actin microfilaments rearrangement, via Rho- GTPases signaling, leading to endothelial barrier dysfunction. DBA/2 mice infected with Plasmodium berghei ANKA develop ALI/ARDS similar to that observed in humans. The purpose of this research was to assess cytoskeletal changes in DBA/2 mice primary microvascular lung endothelial cells (PMLEC), verify the signaling pathways of the Rho- GTPases and analyze the oxidative stress on these cells in the presence of P. berghei ANKA-infected red blood cells (PbA-iRBC). PMLEC were stimulated by TNF, VEGF or IFNγ followed by incubation with PbA-iRBC. Immunofluorescence assays were performed to analyze actin microfilaments rearrangement and microtubules destabilization. Western blot for RhoA, Cdc42 and MLC proteins were conducted to assess alterations in signaling pathways of Rho-GTPases. In addition, a fluorimetric assay was performed to detect the production of reactive oxygen species resulting from PbA-iRBC stimulus. P. berghei ANKA, VEGF, TNF and IFNγ stimuli, in association or not, caused morphological disturbances in actin microfilaments of PMLEC and an increase of intercellular spaces. Moreover, immunofluorescence images showed microtubules destabilization and FAK dephosphorylation in these cells, caused by PbA-iRBC. The permeability assay showed that PbA-iRBC induced an increase of microvascular permeability in PMLEC. In addition, PMLEC stimulated by PbA-iRBC, showed elevated production of ROS, which may be contributing to oxidative stress and increasing the damage of endothelial cells, as well as an increase of vascular permeability. Interestingly, these endothelial changes may be related to the increased RhoA/Cdc42 protein expressions ratio, augmented protein expression of phosphorylated MLC and RhoA activation signal. Taken together, these data demonstrate the involvement of P. berghei ANKA-infected red blood cells in cytoskeleton disorganization and alveolar-capillary barrier dysfunction, through of RhoA / Rho-kinase signaling pathway, which may contribute to ALI/ARDS pathogenesis

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La anemia drepanocítica es una enfermedad con un alto índice de morbilidad que afecta la calidad de vida de los pacientes que la padecen. El priapismoes una complicación frecuente de la enfermedad y se define como una erección dolorosa, prolongada y persistente del pene de más de 4 horas de duración,sin estimulación sexual asociada. El 95 por ciento de las crisis de priapismo en el paciente con anemia drepanocíticason de tipo isquémico o de bajo flujo. En este trabajo se revisan los nuevos mecanismos moleculares que explican la patogenia del priapismo isquémico y que son la base de futuras posibles dianas terapéuticas para su tratamiento(AU)

Sickle cell anaemia (SCD) is a disorder with a high index of morbidity, affecting the quality of life of these patients. Priapism is a common complication of SCD and it is characterized by a prolonged and persistent erection of the penis lasting more than 4 hours without associated sexual stimulation. The 95 percent of priapism crisis in SCD patients are ischemic type. In this paper we review the new molecular mechanisms implicated in the pathogenesis of ischemic priapism and provide the basis for potential future therapie(AU)

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La anemia drepanocítica es una enfermedad con un alto índice de morbilidad que afecta la calidad de vida de los pacientes que la padecen. El priapismo es una complicación frecuente de la enfermedad y se define como una erección dolorosa, prolongada y persistente del pene de más de 4 horas de duración,sin estimulación sexual asociada. El 95 por ciento de las crisis de priapismo en el paciente con anemia drepanocítica son de tipo isquémico o de bajo flujo. En este trabajo se revisan los nuevos mecanismos moleculares que explican la patogenia del priapismo isquémico y que son la base de futuras posibles dianas terapéuticas para su tratamiento(AU)

Sickle cell anaemia (SCD) is a disorder with a high index of morbidity, affecting the quality of life of these patients. Priapism is a common complication of SCD and it is characterized by a prolonged and persistent erection of the penis lasting more than 4 hours without associated sexual stimulation. The 95 percent of priapism crisis in SCD patients are ischemic type. In this paper we review the new molecular mechanisms implicated in the pathogenesis of ischemic priapism and provide the basis for potential future therapies(AU)

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AIMS: The rates of erectile dysfunction (ED) in heart failure (HF) are extremely high. This study tested the hypothesis that rats with HF display ED and that HF leads to increased sympathetic-mediated contractile tone of the cavernous tissue and/or internal pudendal arteries (IPA) as potential mechanisms contributing to ED. MAIN METHODS: HF was induced in Wistar rats by ligation of the left anterior descending coronary artery. Changes in the ratio of intracavernosal pressure/mean arterial pressure (ICP/MAP) after electrical stimulation of major pelvic ganglion were determined in vivo. Cavernosal and IPA contractions were induced by electric field stimulation (EFS) and phenylephrine. RhoA, Rho kinase 2 (ROCK 2) and myosin phosphatase target protein 1 (MYPT-1) protein expression and phosphorylation levels were also determined. KEY FINDINGS: HF rats display impaired erectile function represented by decreased ICP/MAP responses. EFS-mediated contractions were increased by HF in cavernous tissue and IPA. Contractions induced by phenylephrine were increased in cavernous tissue of HF rats, but decreased in IPA rings. Moreover, HF decreased RhoA protein expression, but increased ROCK 2 and MYPT-1 phosphorylation levels in cavernous tissue. In conclusion, rats with HF induced by myocardial infarction display ED in vivo and increased sympathetic-mediated contractile responses in cavernous tissue and IPA. Increased sympathetic-mediated contractile responses were associated with increased ROCK 2 and MYPT-1 phosphorylation in cavernosal tissue, suggesting the involvement of ROCK signaling pathway in ED genesis. SIGNIFICANCE: Our findings suggest new mechanisms linking HF to ED, providing potential therapeutic targets for treating ED associated to HF.

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