Abstract P132: A Kidney-Targeted Nanoparticle To Augment Renal Lymphatic Density Decreases Blood Pressure In Mice With L-NAME- And Angiotensin II-Induced Hypertension

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Bethany L Goodlett ◽  
Eunsoo Yoo ◽  
Chang Sun Kang ◽  
Dakshnapriya Balasubbramanian ◽  
Sydney Love ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Immune Cells ◽  
Flow Cytometric Analysis ◽  
Lymphatic Vessels ◽  
Fold Increase ◽  
Lower Systolic Blood Pressure ◽  
Induced Hypertension ◽  
Integral Role ◽  
Lymphatic Vasculature

Chronic interstitial inflammation and renal infiltration of activated immune cells play an integral role in hypertension. Lymphatic vessels attenuate inflammation by trafficking activated immune cells and excess fluid from the interstitial space to lymph nodes. Previously, our laboratory demonstrated that genetically inducing renal lymphangiogenesis could treat hypertension in three different mouse models. In an effort to translate these findings into a clinical treatment, we hypothesized that a targeted nanoparticle could deliver the pro-lymphangiogenic factor VEGF-C156S to the kidney, induce lymphangiogenesis, and lower blood pressure in hypertensive mice. A micellar nanoparticle was developed with the capacity to deliver protein to the kidney, as demonstrated through delivery trials. This nanoparticle was loaded with VEGF-C156S and injected into mice with LNAME-induced hypertension (LHTN) or angiotensin II-induced hypertension (AIIHTN) via tail vein every 3 days. Compared to hypertensive mice injected with VEGF-C156S only (no nanoparticle) every 3 days, nanoparticle-treated mice exhibited a significantly lower systolic blood pressure (SBP) after 4 injections (LHTN SBP: 160±5 vs. 120±3 mmHg, p<0.001; AIIHTN SBP: 150±8 vs. 126±6 mmHg, p=0.03). Immunolabeled kidney sections from nanoparticle-treated LHTN mice showed a significant increase in podoplanin+ pixels, corresponding to an increase in lymphatic vessel density (p<0.01). A 5-fold increase in renal gene expression of podoplanin in nanoparticle-treated LHTN mice further supported this finding (p=0.01). Flow cytometric analysis of the nanoparticle-treated LHTN mice showed decreased renal CD45+F4/80+CD11c- cells, while AIIHTN mice revealed decreased levels of renal CD45+CD3e+, CD45+CD4+CD8-, and CD45+F4/80+CD11c+ cells (p<0.01, p=0.03, and p<0.001, respectively) when compared to their respective hypertensive groups. These data support our previous findings that expanding the renal lymphatic vasculature can treat existing hypertension by reducing renal immune cells. The results of this study may provide clinicians with a renal lymphatic-targeted therapeutic for treating hypertensive patients.

Abstract MP03: ROCK2 Specific Inhibition Attenuates Angiotensin II-induced Hypertension In Mice

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Daniel J Fehrenbach ◽  
Meena S Madhur
Keyword(s):  
Blood Pressure ◽  
T Cell ◽  
Angiotensin Ii ◽  
Repeated Measures ◽  
Flow Cytometric Analysis ◽  
Coiled Coil ◽  
Ang Ii ◽  
Induced Hypertension

Hypertension, or an elevated blood pressure, is the primary modifiable risk factor for cardiovascular disease, the number one cause of mortality worldwide. We previously demonstrated that Th17 activation and interleukin 17A (IL-17A)/IL-21 production is integral for the full development of a hypertensive phenotype as well as the renal and vascular damage associated with hypertension. Rho-associated coiled-coil containing protein Kinase 2 (ROCK2) serves as a molecular switch upregulating Th17 and inhibiting regulatory T cell (Treg) differentiation. We hypothesize that hypertension is characterized by excessive T cell ROCK2 activation leading to increased Th17/Treg ratios and ultimately end-organ damage. We first showed in vitro that KD025, an experimental orally bioavailable ROCK2 inhibitor inhibits Th17 cell proliferation and IL-17A/IL-21 production. To determine if hypertensive stimuli such as endothelial stretch increases T cell ROCK2 expression, we cultured human aortic endothelial cells exposed to 5% (normotensive) or 10% (hypertensive) stretch with circulating human T cells and HLA-DR+ antigen presenting cells. Hypertensive stretch increased T cell ROCK2 expression 2-fold. We then tested the effect of ROCK2 inhibition with KD025 (50mg/kg i.p. daily) in vivo on angiotensin II (Ang II)-induced hypertension. Treatment with KD025 significantly attenuated the hypertensive response within 1 week of Ang II treatment (systolic blood pressure: 139± 8 vs 108±7mmHg) and this persisted for the duration of the 4 week study reaching blood pressures 20 mmHg lower (135±13mmHg) than vehicle treated mice (158±4mmHg p<0.05 effect of treatment 2-way Repeated Measures ANOVA). Flow cytometric analysis of tissue infiltrating leukocytes revealed that KD025 treatment increased Treg/Th17 ratios in the kidney (0.61±0.03 vs 0.79±0.08, p<0.05 student’s t-test). Thus, T cell ROCK2 may be a novel therapeutic target for the treatment of hypertension.

scholarly journals Role of the Na+/H+ exchanger 3 in angiotensin II-induced hypertension

2015 ◽  
Vol 47 (10) ◽  
pp. 479-487 ◽  
Author(s):  
Xiao C. Li ◽  
Gary E. Shull ◽  
Elisa Miguel-Qin ◽  
Jia L. Zhuo
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Glycogen Synthase ◽  
Proximal Tubules ◽  
Dependent Manner ◽  
Ang Ii ◽  
Lower Systolic Blood Pressure ◽  
Salt Wasting ◽  
Pressor Responses ◽  
Induced Hypertension

The renal mechanisms responsible for angiotensin II (ANG II)-induced hypertension remain incompletely understood. The present study tested the hypothesis that the Na+/H+ exchanger 3 (NHE3) is required for ANG II-induced hypertension in mice. Five groups of wild-type ( Nhe3 +/+) and Nhe3 −/− mice were treated with vehicle or high pressor doses of ANG II (1.5 mg/kg/day ip, via minipump for 2 wk, or 10 pmol/min iv for 30 min). Under basal conditions, Nhe3 −/− mice had significantly lower systolic blood pressure (SBP) and mean intra-arterial pressure (MAP) ( P < 0.01), 24 h urine ( P < 0.05), urinary Na+ ( P < 0.01) and urinary K+ excretion ( P < 0.01). In response to ANG II, SBP and MAP markedly increased in Nhe3 +/+ mice in a time-dependent manner, as expected ( P < 0.01). However, these acute and chronic pressor responses to ANG II were significantly attenuated in Nhe3 −/− mice ( P < 0.01). Losartan blocked ANG II-induced hypertension in Nhe3 +/+ mice but induced marked mortality in Nhe3 −/− mice. The attenuated pressor responses to ANG II in Nhe3 −/− mice were associated with marked compensatory humoral and renal responses to genetic loss of intestinal and renal NHE3. These include elevated basal plasma ANG II and aldosterone and kidney ANG II levels, salt wasting from the intestines, increased renal AQP1, Na+/HCO3−, and Na+/K+-ATPase expression, and increased PKCα, mitogen-activated protein kinases ERK1/2, and glycogen synthase kinase 3αβ signaling proteins in the proximal tubules ( P < 0.01). We concluded that NHE3 in proximal tubules of the kidney, along with NHE3 in intestines, is required for maintaining basal blood pressure as well as the full development of ANG II-induced hypertension.

scholarly journals A Kidney-Targeted Nanoparticle to Augment Renal Lymphatic Density Decreases Blood Pressure in Hypertensive Mice

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 84
Author(s):  
Bethany L. Goodlett ◽  
Chang Sun Kang ◽  
Eunsoo Yoo ◽  
Shobana Navaneethabalakrishnan ◽  
Dakshnapriya Balasubbramanian ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Immune Cells ◽  
Fractional Excretion ◽  
Vegf Receptor ◽  
Nanoparticle Delivery ◽  
Fractional Excretion Of Sodium ◽  
Induced Hypertension ◽  
Integral Role ◽  
Factor C ◽  
Endothelial Growth Factor

Chronic interstitial inflammation and renal infiltration of activated immune cells play an integral role in hypertension. Lymphatics regulate inflammation through clearance of immune cells and excess interstitial fluid. Previously, we demonstrated increasing renal lymphangiogenesis prevents hypertension in mice. We hypothesized that targeted nanoparticle delivery of vascular endothelial growth factor-C (VEGF-C) to the kidney would induce renal lymphangiogenesis, lowering blood pressure in hypertensive mice. A kidney-targeting nanoparticle was loaded with a VEGF receptor-3-specific form of VEGF-C and injected into mice with angiotensin II-induced hypertension or LNAME-induced hypertension every 3 days. Nanoparticle-treated mice exhibited increased renal lymphatic vessel density and width compared to hypertensive mice injected with VEGF-C alone. Nanoparticle-treated mice exhibited decreased systolic blood pressure, decreased pro-inflammatory renal immune cells, and increased urinary fractional excretion of sodium. Our findings demonstrate that pharmacologically expanding renal lymphatics decreases blood pressure and is associated with favorable alterations in renal immune cells and increased sodium excretion.

scholarly journals Proximal Tubule-Specific Deletion of Angiotensin II Type 1a Receptors in the Kidney Attenuates Circulating and Intratubular Angiotensin II–Induced Hypertension in PT- Agtr1a −/− Mice

Hypertension ◽  
2021 ◽  
Author(s):  
Xiao Chun Li ◽  
Ana Paula Oliveira Leite ◽  
Xiaowen Zheng ◽  
Chunling Zhao ◽  
Xu Chen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Fusion Protein ◽  
Proximal Tubule ◽  
Proximal Tubules ◽  
Normal Blood ◽  
Ang Ii ◽  
Normal Blood Pressure ◽  
Wild Type ◽  
Induced Hypertension

The present study used a novel mouse model with proximal tubule-specific knockout of AT 1a receptors in the kidney, PT- Agtr1a −/− , to test the hypothesis that intratubular Ang II (angiotensin II) and AT 1a receptors in the proximal tubules are required for maintaining normal blood pressure and the development of Ang II–induced hypertension. Twenty-six groups (n=6–15 per group) of adult male wild-type, global Agtr1a −/− , and PT- Agtr1a −/− mice were infused with Ang II (1.5 mg/kg per day, IP), or overexpressed an intracellular Ang II fusion protein in the proximal tubules for 2 weeks. Basal telemetry blood pressure were ≈15±3 mm Hg lower in PT- Agtr1a −/− than wild-type mice and ≈13±3 mm Hg higher than Agtr1a −/− mice ( P <0.01). Basal glomerular filtration was ≈23.9% higher ( P <0.01), whereas fractional proximal tubule Na + reabsorption was lower in PT- Agtr1a −/− mice ( P <0.01). Deletion of AT 1a receptors in the proximal tubules augmented the pressure-natriuresis response ( P <0.01) and natriuretic responses to salt loading or Ang III infusion ( P <0.01). Ang II induced hypertension in wild-type, PT- Agtr1a −/− and PT- Nhe3 −/− mice, but the pressor response was ≈16±2 mm Hg lower in PT- Agtr1a −/− and PT- Nhe3 −/− mice ( P <0.01). Deletion of AT 1a receptors or NHE3 (Na + /H + exchanger 3) in the proximal tubules attenuated ≈50% of Ang II–induced hypertension in wild-type mice ( P <0.01), but blocked intracellular Ang II fusion protein-induced hypertension in PT- Agtr1a −/− mice ( P <0.01). Taken together, the results of the present study provide new insights into the critical role of intratubular Ang II/AT 1 (AT 1a )/NHE3 pathways in the proximal tubules in normal blood pressure control and the development of Ang II–induced hypertension.

Abstract P145: Renal Inflammation and Injury is Associated with Increased Lymphangiogenesis in Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Sterling C Kneedler ◽  
Lauren Phillips ◽  
Kayla R Hudson ◽  
Katharine M Beckman ◽  
Alan R Parrish ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Immune System ◽  
Immune Cells ◽  
Lymphatic Vessels ◽  
Macrophage Infiltration ◽  
Shr Rats ◽  
Renal Inflammation ◽  
Immune System Activation ◽  
System Activation ◽  
Fischer Rats

Hypertension is associated with immune system activation and inflammation. Renal infiltration of both innate and adaptive immune cells contributes to injury, dysfunction, and increased blood pressure. Activated immune cells that exit blood vessels into the interstitium then travel through lymphatic vessels to draining lymph nodes where they signal to other immune cells to increase the immune response. It is unknown how renal lymphatic vessels change in the context of hypertension, immune system activation, inflammation, and injury. We hypothesized that renal macrophage infiltration, inflammation, and injury would significantly increase lymphangiogenesis in various strains of rats. SHR rats that exhibit hypertension and renal injury (SHR-A3 strain) had significantly increased numbers of renal lymphatic vessels at 40 weeks of age compared to WKY controls (total of 3 fields of view: 52 ± 1 vs. 28 ± 1; p<0.05). This was associated with increased renal macrophage infiltration. SHR rats that exhibit hypertension but minimal renal injury (SHR-B2 strain) had significantly less renal lymphatic vessel numbers compared to WKY controls (25 ± 2 vs. 28 ± 1; p<0.05) and normal levels of macrophages. The signals for lymphangiogenesis, VEGF-C and its receptor VEGF-R3, were both increased significantly at the protein level in the kidneys of SHR-A3 rats at 18 weeks but not different in the kidneys of SHR-B2 rats compared to WKY controls. To test whether the increased lymphangiogensis is due to hypertension and/or renal inflammation and injury, we obtained kidneys from Fischer 344 rats that exhibit normal blood pressure but develop renal inflammation and injury as they age. Compared to kidneys from control 4-month old Fischer rats, kidneys from 20-month and 24-month old Fischer rats had significantly increased numbers of lymphatic vessels (32 ± 3 vs. 74 ± 1 vs. 110 ± 6, respectively; p<0.05) and this was also associated with increased macrophage infiltration. Protein levels of VEGF-C and VEGF-R3 were increased significantly in 20-month old Fischer rats compared to 4-month old controls. These data together demonstrate that renal immune cell infiltration, inflammation, and injury increases lymphangiogenesis.

Abstract 87: The Accumulation of Myeloid-derived Suppressor Cells Is a Compensatory Response to the Development of Hypertension

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Xiao Z Shen ◽  
Peng Shi ◽  
Jorge Giani ◽  
Ellen Bernstein ◽  
Kenneth E Bernstein
Keyword(s):  
Blood Pressure ◽  
T Cell ◽  
Angiotensin Ii ◽  
Critical Role ◽  
Myeloid Cells ◽  
Suppressor Cells ◽  
Myeloid Derived Suppressor Cells ◽  
Compensatory Response ◽  
Immunosuppressive Cell ◽  
Induced Hypertension

The immune system plays a critical role in the development of hypertension. The immune response consists of pro-inflammatory cells, but also immunosuppressive cells that reduce T cell function. An important category of natural immunosuppressive cell is myeloid-derived suppressor cells (MDSC). We now show that blood and spleen CD11b+ Gr1+ myeloid cells are elevated 2-fold in both angiotensin II and L-NAME induced hypertension. These increased myeloid cells are MDSC in that they elevate IL-4R expression and suppress T cell proliferation. When hypertensive mice were depleted of MDSC, using either anti-Gr1 antibody or gemcitabine, there was a 15 mmHg rise in blood pressure and aggravation of T cells activation with increased production of IFN-γ, TNFα and IL-17 in both spleen and kidney. In contrast, adoptive transfer of MDSC reduced blood pressure in angiotensin-II induced hypertension by 25 mmHg (see Figure). These data suggest a new concept, that the accumulation of MDSC is a compensatory response to the inflammation induced by hypertension. They also indicate that MDSC play an important role in regulating blood pressure.

Abstract 476: Renal AT2 Receptor Activation Prevents Sodium Retention And Lowers Blood Pressure In Angiotensin II-Dependent Hypertension

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Shetal H Padia ◽  
Nancy L Howell ◽  
Brandon A Kemp ◽  
John J Gildea ◽  
Susanna R Keller ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Receptor Activation ◽  
Pressure Probe ◽  
Ang Ii ◽  
Induced Hypertension ◽  
Group 5 ◽  
Group 2 ◽  
Angiotensin Type

A major proposed mechanism for the initiation of hypertension involves a primary increase in renal tubular sodium (Na+) reabsorption. Activation of intrarenal angiotensin type-2 receptors (AT2R) increases Na+ excretion; however, the role of intrarenal angiotensin type-2 receptors (AT2R) in the development of hypertension is unknown. Sprague-Dawley rats (N=36) underwent uninephrectomy and telemetric blood pressure probe implantation. Following a 72h recovery, two osmotic minipumps were inserted in each rat, one for chronic systemic delivery of 5% dextrose in water (D5W) or angiotensin II (Ang II, 200 ng/kg/min), and one for chronic intrarenal delivery of D5W (0.25 μL/h x 7d), highly selective AT2R agonist Compound 21 (C-21; 60 ng/kg/min x 7d), or specific AT2R antagonist PD-1223319 (PD; 10 ng/kg/min x 7d). Five groups of rats were studied: Group 1 (Control; N=10): systemic D5W + intrarenal D5W; Group 2 (Ang II-induced hypertension; N=8): systemic Ang II + intrarenal D5W; Group 3 (N=6): systemic Ang II + intrarenal C-21; Group 4 (N=6): systemic Ang II + 48h lead-in intrarenal C-21; Group 5 (N=6): systemic Ang II + intrarenal PD. Systemic Ang II infusion increased mean systolic blood pressure from 126±5 to 190±3 mm Hg over a 7d period in Group 2 (ANOVA F=73; P<1 X 10-6). Intrarenal administration of AT2R agonist C-21 (Groups 3 and 4) markedly inhibited the pressor effect of systemic Ang II (P<0.0001). Intrarenal AT2R antagonist PD (Group 5) augmented the pressor action of Ang II (P<0.0001). Consecutive 24h urinary Na+ excretion (UNaV) was reduced from 0.95±0.04 to 0.34±0.07 μmol/min (P<0.0001) on day 1 of Ang II infusion; Ang II-induced antinatriuresis was inhibited by intrarenal C-21 (P<0.0001) and augmented by intrarenal PD (P<0.0001) during the entire 7d infusion, demonstrating that one of the mechanisms to prevent Ang II-induced hypertension during intrarenal AT2R activation is the abolition of the initial increase in Na+ reabsorption that triggers the hypertensive cascade in this model. Thus, renal AT2Rs represent a novel therapeutic target for the prevention of hypertension.

Abstract P363: Annexin-A1 Deficiency Exaggerates Cardiac Remodeling In Angiotensin II-induced Hypertension

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Kristy Jackson ◽  
Jaideep Singh ◽  
Yen Zhi Ng ◽  
Cheng Peng ◽  
Anida Velagic ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Cardiac Remodeling ◽  
Physiological Role ◽  
Preclinical Model ◽  
Annexin A1 ◽  
Ang Ii ◽  
Cardiac Damage ◽  
Induced Hypertension ◽  
Deficient Mice

Introduction: We have previously demonstrated that the naturally-occurring anti-inflammatory and pro-resolving protein Annexin-A1 (Anx-A1) limits the acute inflammatory response post myocardial infarction, but its impact on chronic inflammation, such as hypertension, has not been explored. This study aims to investigate the role of Anx-A1 in a preclinical model of hypertension, induced by angiotensin-II (Ang-II). Methods: 15-week-old male C57BL/6 or ANXA1 -/- were anesthetized (isoflurane, 2-4% v/v) and implanted with an osmotic minipump randomly assigned to receive Ang-II (0.7mg/kg/day) or vehicle (saline). Radiotelemetry recordings of blood pressure were taken at 10 intermittent timepoints from baseline to the end of the 29-day infusion period. Animals were euthanized with pentobarbitone (100mg/kg; i.p.) at endpoint and organ weights recorded and normalized to bodyweight. Left ventricle (LV) samples were stained with picrosirius red to assess total LV collagen deposition. Results: Ang II-induced mice at the end of the study had elevated mean arterial pressure (MAP), cardiac hypertrophy and fibrosis compared to normotensive mice (Table). Anx-A1 deficient mice given Ang II had an even greater increase in MAP and cardiac remodeling compared to WT. Interestingly, MAP of Anx-A1 deficient mice at baseline is significantly higher compare to C57BL/6 counterparts (Table). Conclusion: This is the first study to demonstrate that deficiency of Anx-A1 exaggerates cardiac remodeling in AngII-induced hypertension, suggesting that endogenous Anx-A1 might play previously unappreciated physiological role in regulating blood pressure. This supports the development of Anx-A1 based pharmacotherapy against hypertension-induced cardiac damage.

Abstract P041: Proximal Tubule-specific Deletion Of Angiotensin Ii Type 1a Receptors In The Kidney Lowers Basal Blood Pressure And Attenuates Angiotensin Ii-induced Hypertension By Increasing Glomerular Filtration And The Pressure-natriuresis Response

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Xiao C Li ◽  
Ana P Leite ◽  
Liang Zhang ◽  
Jia L Zhuo
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Proximal Tubule ◽  
Pressor Response ◽  
Control Group ◽  
Ang Ii ◽  
Induced Hypertension ◽  
Basal Blood Pressure ◽  
Pressure Natriuresis ◽  
Specific Deletion

The present study tested the hypothesis that intratubular angiotensin II (Ang II) and AT 1a receptors in the proximal tubules of the kidney plays an important role in basal blood pressure control and in the development of Ang II-induced hypertension. Mutant mice with proximal tubule-specific deletion of AT 1a receptors in the kidney, PT- Agtr1a -/- , were generated to test the hypothesis. Eight groups (n=7-12 per group) of adult male wild-type (WT) and PT- Agtr1a -/- mice were infused with or without Ang II for 2 weeks (1.5 mg/kg, i.p.). Basal systolic, diastolic, and mean arterial pressures were ~13 ± 3 mmHg lower in PT- Agtr1a -/- than WT mice ( P <0.01). Basal glomerular filtration rate (GFR), as measured using transdermal FITC-sinistrin, was significantly higher in PT- Agtr1a -/- mice (WT: 160.4 ± 7.0 μl/min vs. PT- Agtr1a -/- : 186.0 ± 6.0 μl/min, P <0.05). Basal 24 h urinary Na + excretion (U Na V) was significantly higher in PT- Agtr1a -/- than WT mice ( P <0.01). In response to Ang II infusion, both WT and PT- Agtr1a -/- mice developed hypertension, and the magnitude of the pressor response to Ang II was similar in WT (Δ43 ± 3 mmHg, P <0.01) and PT- Agtr1a -/- mice (Δ39 ± 5 mmHg, P <0.01). However, the absolute blood pressure level was still 16 ± 3 mmHg lower in PT- Agtr1a -/- mice ( P <0.01). Ang II significantly decreased GFR to 132.2 ± 7.0 μl/min in WT mice ( P <0.01), and to 129.4 ± 18.6 μl/min in PT- Agtr1a -/- mice ( P <0.01), respectively. In WT mice, U Na V increased from 139.3 ± 22.3 μmol/24 h in the control group to 196.4 ± 29.6 μmol/24 h in the Ang II-infused group ( P <0.01). In PT- Agtr1a -/- mice, U Na V increased from 172.0 ± 10.2 μmol/24 h in the control group to 264.7 ± 35.4 μmol/24 h in the Ang II-infused group ( P <0.01). The pressor response to Ang II was attenuated, while the natriuretic response was augmented by losartan in WT and PT- Agtr1a -/- mice ( P <0.01). Finally, proximal tubule-specific deletion of AT 1a receptors significantly augmented the pressure-natriuresis response and natriuretic responses to acute saline infusion ( P <0.01) or a 2% high salt diet ( P <0.01). We concluded that deletion of AT 1a receptors selectively in the proximal tubules lowers basal blood pressure and attenuates Ang II-induced hypertension by increasing GFR and promoting the natriuretic response in PT- Agtr1a -/- mice.

scholarly journals Site-1 Protease-Derived Soluble (Pro)Renin Receptor Contributes to Angiotensin II–Induced Hypertension in Mice

Hypertension ◽  
2020 ◽  
Author(s):  
Ye Feng ◽  
Kexin Peng ◽  
Renfei Luo ◽  
Fei Wang ◽  
Tianxin Yang
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Collecting Duct ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Short Circuit Current ◽  
Duct Cell ◽  
Ang Ii ◽  
Cortical Collecting Duct ◽  
Induced Hypertension

Activation of PRR ([pro]renin receptor) contributes to enhancement of intrarenal RAS and renal medullary α-ENaC and thus elevated blood pressure during Ang II (angiotensin II) infusion. The goal of the present study was to test whether such action of PRR was mediated by sPRR (soluble PRR), generated by S1P (site-1 protease), a newly identified PRR cleavage protease. F1 B6129SF1/J mice were infused for 6 days with control or Ang II at 300 ng/kg per day alone or in combination with S1P inhibitor PF-429242 (PF), and blood pressure was monitored by radiotelemetry. S1P inhibition significantly attenuated Ang II–induced hypertension accompanied with suppressed urinary and renal medullary renin levels and expression of renal medullary but not renal cortical α-ENaC expression. The effects of S1P inhibition were all reversed by supplement with histidine-tagged sPRR termed as sPRR-His. Ussing chamber technique was performed to determine amiloride-sensitive short-circuit current, an index of ENaC activity in confluent mouse cortical collecting duct cell line cells exposed for 24 hours to Ang II, Ang II + PF, or Ang II + PF + sPRR-His. Ang II–induced ENaC activity was blocked by PF, which was reversed by sPRR-His. Together, these results support that S1P-derived sPRR mediates Ang II–induced hypertension through enhancement of intrarenal renin level and activation of ENaC.

Sign in / Sign up

Export Citation Format

Share Document