Objective This study examined vascular actions of angiotensin 1–7 (ANG 1–7) in human atrial and adipose arterioles. Approach and Results The endothelial-derived hyperpolarizing factor of flow mediated dilation (FMD) switches from anti-proliferative nitric oxide (NO) to pro-atherosclerotic hydrogen peroxide (H2O2) in arterioles from humans with coronary artery disease (CAD). Given the known vasoprotective properties of ANG 1–7, we tested the hypothesis that overnight ANG 1–7 treatment restores the NO-component of FMD in arterioles from CAD patients. Endothelial telomerase activity is essential for preserving the NO-component of vasodilation in the human microcirculation, thus we also tested whether telomerase activity was necessary for ANG 1–7 mediated vasoprotection by treating separate arterioles with ANG 1–7 ± the telomerase inhibitor BIBR-1532. ANG 1–7 dilated arterioles from patients without CAD, whereas dilation was significantly reduced in arterioles from CAD patients. In atrial arterioles from CAD patients incubated with ANG 1–7 overnight, the NO synthase inhibitor L-NAME abolished FMD while the H2O2 scavenger PEG catalase had no effect. Conversely, in vessels incubated with ANG 1–7 + BIBR-1532, L-NAME had no effect on FMD but PEG catalase abolished dilation. In cultured human coronary artery endothelial cells, ANG 1–7 significantly increased telomerase activity. These results indicate that ANG 1–7 dilates human microvessels, and dilation is abrogated in the presence of CAD. Further, ANG 1–7 treatment is sufficient to restore the NO component of FMD in arterioles from CAD patients in a telomerase-dependent fashion. Conclusion ANG 1–7 exerts vasoprotection in the human microvasculature via modulation of telomerase activity.

Introduction The present study explored the mechanism of mTORC2 activation in Sprague Dawley (SD) rats and the protective effect of mTORC2 inhibition in salt‐induced hypertension and kidney injury in Dahl salt‐sensitive (SS) rats. Although there are evidences that the mTORC2 pathway contributes to renal podocyte homeostasis and tubular epithelial Na+ and K+ transport, this pathway has remained unexplored in hypertension. Since excess production of H2O2 in the kidney is the hallmark of salt‐induced hypertension in the SS rat, we hypothesized that H2O2 may stimulate mTORC2 and contributes to this salt‐sensitive form of hypertension. Methods H2O2 (347 nmol/Kg/min) was chronically infused for 3 days into renal medullary interstitium of unilaterally nephrectomized (SD) rats to determine the in vivo consequence of H2O2 upon mTORC2 activity. To test the protective effect of PP242 (ATP competitive inhibitor of both mTORC1 and mTORC2), SS rats were divided in to four groups. Groups 1 and 2: vehicle (group 1) or PP242 (group 2) was administrated daily (i.p., 15 mg/Kg/day) for 4 days to SS rats fed a 0.4% NaCl diet (control), then switched to a 4.0% NaCl diet for 21 days. Groups 3 and 4: rats were fed 4.0 % NaCl for 7 days before being treated with vehicle (group 3) or PP242 (group 4) for next 14 days while maintained on the 4.0 % NaCl diet. Kidneys were harvested to measure the protein levels of pAKT S473 and AKT by Western blots. mTORC2 activity was determined by assessing the ratio pAKTS473 and AKT. Microalbuminuria was quantified and kidney sections were immunostained with antibody against anti‐CD3 to determine the renal T lymphocytes infiltration. Results A significant increase of mTORC2 (pAKT S473/AKT) activity was observed in the renal cortex of SD rats infused with H2O2 for 3 days compared to saline infused rats. PP242 treatment significantly reduced H2O2 stimulated mTORC2 activity in nephron segments isolated from SS rat kidneys in vitro. Daily adminsiration of PP242 significantly reduced salt‐induced blood pressure in SS rats which averaged 119 ± 2 mmHg in group 2 rats (n=7) compared to 168 ± 3 mmHg in group 1 rats (n=7). Importantly, PP242 reversed the hypertension from 143 ± 3 mmHg to the base line 126 ± 5 mmHg in 2 days and maintained it at similar levels over the next 12 days in the group 4 rats (n=7) compared with group 3 rats (n=6). Albuminuria was greatly reduced with urine albumin excretion (mg/day) averaging 32.8 ± 3 in group 2 rats compared to 256 ± 37 in group 1 rats. PP242 treatment notably reduced infiltration of T lymphocytes in the kidneys of SS rats fed a 4.0% NaCl diet. CD3+ cells/mm2 averaging 36.0 ± 11.0 compared to 157.0 ± 40.0 in the cortex and 24.0 ± 9.0 compared to 218.0 ± 24.0 in the outer medulla in group 2 versus group 1 rats. Conclusion These data show that mTORC2 is required for the initiation of salt‐induced hypertension and therapeutic suppression of this pathway prevents and reverses the salt‐induced hypertension and and kidney injury in SS rats. This abstract is from the Experimenta...

Cardiovascular-related pathologies are the single leading cause of death in patients with chronic kidney disease (CKD). Previously, we found that a 5/6th nephrectomy model of CKD leads to an upregulation of miR-21-5p in the left ventricle, targeting peroxisome proliferator-activated receptor-α and altering the expression of numerous transcripts involved with fatty acid oxidation and glycolysis. In the present study, we evaluated the potential for knockdown or overexpression of miR-21-5p to regulate lipid content, lipid peroxidation, and mitochondrial respiration in H9C2 cells. Cells were transfected with anti-miR-21-5p (40 nM), pre-miR-21-5p (20 nM), or the appropriate scrambled oligonucleotide controls before lipid treatment in culture or as part of the Agilent Seahorse XF fatty acid oxidation assay. Overexpression of miR-21-5p attenuated the lipid-induced increase in cellular lipid content, whereas suppression of miR-21-5p augmented it. The abundance of malondialdehyde, a product of lipid peroxidation, was significantly increased with lipid treatment in control cells but attenuated in pre-miR-21-5p-transfected cells. This suggests that miR-21-5p reduces oxidative stress. The cellular oxygen consumption rate (OCR) was increased in both pre-miR-21-5p- and anti-miR-21-5p-transfected cells. Levels of intracellular ATP were significantly higher in anti-mR-21-5p-transfected cells. Pre-miR-21-5p blocked additional increases in OCR in response to etomoxir and palmitic acid. Conversely, anti-miR-21-5p-transfected cells exhibited reduced OCR with both etomoxir and palmitic acid, and the glycolytic capacity was concomitantly reduced. Together, these results indicate that overexpression of miR-21-5p attenuates both lipid content and lipid peroxidation in H9C2 cells. This likely occurs by reducing cellular lipid uptake and utilization, shifting cellular metabolism toward reliance on the glycolytic pathway. NEW & NOTEWORTHY Both overexpression and suppression of miR-21-5p augment basal and maximal mitochondrial respiration. Our data suggest that reliance on glycolytic and fatty acid oxidation pathways can be modulated by the abundance of miR-21-5p within the cell. miR-21-5p regulation of mitochondrial respiration can be modulated by extracellular lipids.

Cardiovascular (CV) and renal diseases are increasingly prevalent in the United States and globally. CV-related mortality is the leading cause of death in the United States, while renal-related mortality is the 8th. Despite advanced therapeutics, both diseases persist, warranting continued exploration of disease mechanisms to develop novel therapeutics and advance clinical outcomes for cardio-renal health. CV and renal diseases increase with age, and there are sex differences evident in both the prevalence and progression of CV and renal disease. These age and sex differences seen in cardio-renal health implicate sex hormones as potentially important regulators to be studied. One such regulator is G protein-coupled estrogen receptor 1 (GPER1). GPER1 has been implicated in estrogen signaling and is expressed in a variety of tissues including the heart, vasculature, and kidney. GPER1 has been shown to be protective against CV and renal diseases in different experimental animal models. GPER1 actions involve multiple signaling pathways: interaction with aldosterone and endothelin-1 signaling, stimulation of the release of nitric oxide, and reduction in oxidative stress, inflammation, and immune infiltration. This review will discuss the current literature regarding GPER1 and cardio-renal health, particularly in the context of aging. Improving our understanding of GPER1-evoked mechanisms may reveal novel therapeutics aimed at improving cardio-renal health and clinical outcomes in the elderly.

The mechanisms that regulate renal survival and atrophy under pathological stress remain incompletely understood. This knowledge is essential for developing new strategies to preserve renal function in patients with various forms of renal disease. We have utilized the 5/6 nephrectomy (5/6Nx) model to study the effects of renal insufficiency in 10 week old male Sprague Dawley rats. In this model excision of 2/3 of the left kidney and the entire right kidney induced substantial hypertrophy of the remnant kidney within 7 weeks of surgery. Conversely, excision of 2/3 of the left kidney, while leaving the right kidney intact (1/3 nephrectomy; 1/3Nx), resulted in atrophy of the remnant kidney within the same period. This lead us to hypothesize that removal of the right kidney 7 weeks after 1/3 surgery could induce hypertrophic remodeling of the left remnant kidney even after atrophic remodeling has occurred. To test this, we performed sham surgeries consisting of laparotomy and renal vessel isolation, right uninephrectomy (1Nx), 1/3Nx, or 5/6Nx surgery, as described above (n= 4–11/group). After 7 weeks we performed ultrasound analysis to evaluate the transverse renal cross‐sectional area (CSA) of the left kidney in each model. Sham surgery was then performed on all animals except for a subset of the 1/3Nx group which had their right kidneys excised. The animals were allowed to recover for another 3 weeks before the left kidney remodeling was again evaluated by ultrasound, acute anesthetized blood pressure was measured, and blood and tissues were collected for analysis. Statistical analysis of ultrasound data was completed using two‐way RM ANOVA, and all other by one‐way ANOVA. Ultrasound analysis of left kidney CSA revealed significant hypertrophy in the 1Nx and 5/6Nx models by week 7, when compared to sham‐operated controls, with no further increase in size evident by week 10. We observed the anticipated reduction in CSA in the 1/3Nx group by week 7 (1.06 ± 0.02, sham vs. 0.58 ± 0.01 cm2, 1/3Nx; p <0.05). The 1/3Nx rats subjected to removal of the right kidney experienced a significant hypertrophy of the remnant kidney (1.31 ± 0.04 cm2) between weeks 7 and 10, however this hypertrophy failed to reach the level observed in the 5/6Nx model (2.06 ± 0.05 cm2). Those 1/3Nx rats that retained their right kidney had no apparent change in remnant kidney size by week 10 (0.56 ± 0.03 cm2). These changes in renal dimensions were consistent with wet weights of the remnant kidney weights. Systolic and diastolic blood pressures measured at the end of the study were not statistically different from that of sham operated controls in any surgical group, however pressures tended to be higher in the 1/3Nx rats that had their right kidneys removed at week 7. We determined that removal of the right kidney could stimulate an atrophied left kidney to hypertrophy. In conclusion, the changes observed in this study suggest that these surgical models will allow us to study the mechanisms that regulate hypertrophy and atrophy.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.