A 779

There is evidence to support that ROSs are increased in Parkinson's disease (PD). Our recent research showed that angiotensin II (Ang II) participated in the pathogenesis of PD by triggering oxidative stress. Angiotensin-(1-7)[Ang-(1-7)] has been shown to moderate the adverse effects of the Ang II in many diseases. The purpose of the present study was to determine whether the Ang-(1-7) could have similar effects in CATH.a neurons. We used rotenone-induced neuron injury models to evaluate changes in cultured CATH.a cell lines levels of SOD, GSH and ROS. We also evaluated the expression of AT;1;, AT;2;, Mas receptors and Nox1, Nox2, P47;phox;, Hsp70 in treated with PBS, rotenone, Ang-(1-7), or Mas receptor antagonist A-779, alone and combined. The qRT-PCR and western blot were used to detect mRNA and protein levels of the AT;1;, AT;2;, Mas receptors and Nox1, Nox2, P47;phox;, Hsp70. The levels of SOD and GSH were determined by using commercial kits. The ROS generation was measured by the fluorescent probe assay. Ang-(1-7) in our current study significantly decreased rotenone-induced oxidative damage and increased the SOD and GSH generation. In addition, Ang-(1-7) significantly elevated Mas receptor expression and reduced NADPH oxidase activation, and these effects were completely eliminated by the A-779.

The peptide angiotensin-(1-7) [Ang-(1-7)] is known to enhance water transport in rat inner medullary collecting duct (IMCD). The aim of this study was to determine the mechanism of the Ang-(1-7) effect on osmotic water permeability (Pf). Pf was measured in the normal rat IMCD perfused in vitro in presence of agonists [Ang-(1-7), arginine vasopressin (AVP) and Ang-(3-8)], and antagonists of the angiotensin and the vasopressin cascade. Ang-(1-7), but not Ang-(3-8), increased Pf significantly. The effect of Ang-(1-7) on Pf was abolished by its selective antagonist, A-779, added before or after Ang-(1-7). Prostaglandin E2 and the protein kinase A inhibitor H8 also blocked the Ang-(1-7) effect. Blockade of vasopressin V1 receptors by antagonists did not change the Ang-(1-7) effect, but pre-treatment with a V2 antagonist abolished the effect of Ang-(1-7) on Pf. Similarly, pre-treatment with A-779 inhibited AVP's effect on Pf. Forskolin-stimulated Pf was blocked both by A-779 and by the V2 antagonist. Finally, Ang-(1-7) increased cAMP levels in fresh IMCD cell suspensions whilst the forskolin-stimulated cAMP synthesis was decreased by A-779 and the V2 antagonist. These data provide evidence that Ang-(1-7) interacts via its receptor with the AVP V2 system through a mechanism involving adenylate-cyclase activation.

The renin-angiotensin system (RAS) plays an important role in renal physiology and kidney injury. Although the cellular effects of the RAS activation are generally attributed to angiotensin II (ANG II), the recent identification of angiotensin-converting enzyme 2 has shifted the focus to other peptides including Ang-(1-7). The G protein-coupled receptor for Ang-(1-7), mas, is expressed by mesangial cells (MC) but the signal transduction pathways activated by Ang-(1-7) in MC have not been fully elucidated. Accordingly, we studied the effect of Ang-(1-7) on extracellular signal-related kinase (ERK)1/2 activation in rat MC. Ang-(1-7)-induced ERK1/2 phosphorylation in MC is time- and concentration-dependent. Pretreatment of MC with the mas receptor antagonist A-779 but not the AT(1) antagonist losartan or the AT(2) antagonist PD123319 abrogated ERK1/2 activation. Neither pretreatment with the NADPH oxidase inhibitors diphenyleneiodonium and apocynin nor pretreatment with the epidermal growth factor (EGF) receptor antagonists AG1478 and PD158780 attenuated Ang-(1-7)-induced activation of ERK1/2. Even though each of these compounds abolished ANG II-induced activation of ERK1/2. Ang-(1-7) increased intracellular cAMP levels and activated protein kinase A (PKA) and inhibition of either adenylyl cyclase or PKA activity attenuated Ang-(1-7)-induced ERK1/2 activation.