scholarly journals Angiotensin II-induced hypertension and cardiac hypertrophy are differentially mediated by TLR3- and TLR4-dependent pathways

2019 ◽  
Vol 316 (5) ◽  
pp. H1027-H1038 ◽  
Author(s):  
Madhu V. Singh ◽  
Michael Z. Cicha ◽  
Sarah Nunez ◽  
David K. Meyerholz ◽  
Mark W. Chapleau ◽  
...  

Toll-like receptors (TLR) are key components of the innate immune system that elicit inflammatory responses through the adaptor proteins myeloid differentiation protein 88 (MyD88) and Toll-interleukin receptor domain-containing adaptor protein-inducing interferon-β (TRIF). Previously, we demonstrated that TRIF mediates the signaling of angiotensin II (ANG II)- induced hypertension and cardiac hypertrophy. Since TRIF is activated selectively by TLR3 and TLR4, our goals in this study were to determine the roles of TLR3 and TLR4 in mediating ANG II-induced hypertension and cardiac hypertrophy, and associated changes in proinflammatory gene expression in heart and kidney. In wild-type (WT) mice, ANG II infusion (1,000 ng·kg−1·min−1 for 3 wk) increased systolic blood pressure and caused cardiac hypertrophy. In ANG II-infused TLR4-deficient mice ( Tlr4del), hypertrophy was significantly attenuated despite a preserved or enhanced hypertensive response. In contrast, in TLR3-deficient mice ( Tlr3−/−), both ANG II-induced hypertension and hypertrophy were abrogated. In WT mice, ANG II increased the expression of several proinflammatory genes in hearts and kidneys that were attenuated in both TLR4- and TLR3-deficient mice compared with WT. We conclude that ANG II activates both TLR4-TRIF and TLR3-TRIF pathways in a nonredundant manner whereby hypertension is dependent on activation of the TLR3-TRIF pathway and cardiac hypertrophy is dependent on both TLR3-TRIF and TLR4-TRIF pathways. NEW & NOTEWORTHY Angiotensin II (ANG II)-induced hypertension is dependent on the endosomal Toll-like receptor 3 (TLR3)-Toll-interleukin receptor domain-containing adaptor protein-inducing interferon-β (TRIF) pathway of the innate immune system but not on cell membrane localized TLR4. However, ANG II-induced cardiac hypertrophy is regulated by both TLR4-TRIF and TLR3-TRIF pathways. Thus, ANG II-induced rise in systolic blood pressure is independent of TLR4-TRIF effect on cardiac hypertrophy. The TLR3-TRIF pathway may be a potential target of therapeutic intervention.

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Kristy Jackson ◽  
Jaideep Singh ◽  
Yen Zhi Ng ◽  
Cheng Peng ◽  
Anida Velagic ◽  
...  

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.


2019 ◽  
Vol 317 (2) ◽  
pp. F254-F263
Author(s):  
Anne D. Thuesen ◽  
Stine H. Finsen ◽  
Louise L. Rasmussen ◽  
Ditte C. Andersen ◽  
Boye L. Jensen ◽  
...  

T-type Ca2+ channel Cav3.1 promotes microvessel contraction ex vivo. It was hypothesized that in vivo, functional deletion of Cav3.1, but not Cav3.2, protects mice against angiotensin II (ANG II)-induced hypertension. Mean arterial blood pressure (MAP) and heart rate were measured continuously with chronically indwelling catheters during infusion of ANG II (30 ng·kg−1·min−1, 7 days) in wild-type (WT), Cav3.1−/−, and Cav3.2−/− mice. Plasma aldosterone and renin concentrations were measured by radioimmunoassays. In a separate series, WT mice were infused with ANG II (100 ng·kg−1·min−1) with and without the mineralocorticoid receptor blocker canrenoate. Cav3.1−/− and Cav3.2−/− mice exhibited no baseline difference in MAP compared with WT mice, but day-night variation was blunted in both Cav3.1 and Cav3.2−/− mice. ANG II increased significantly MAP in WT, Cav3.1−/−, and Cav3.2−/− mice with no differences between genotypes. Heart rate was significantly lower in Cav3.1−/− and Cav3.2−/− mice compared with control mice. After ANG II infusion, plasma aldosterone concentration was significantly lower in Cav3.1−/− compared with Cav3.2−/− mice. In response to ANG II, fibrosis was observed in heart sections from both WT and Cav3.1−/− mice and while cardiac atrial natriuretic peptide mRNA was similar, the brain natriuretic peptide mRNA increase was mitigated in Cav3.1−/− mice ANG II at 100 ng/kg yielded elevated pressure and an increased heart weight-to-body weight ratio in WT mice. Cardiac hypertrophy, but not hypertension, was prevented by the mineralocorticoid receptor blocker canrenoate. In conclusion, T-type channels Cav3.1and Cav3.2 do not contribute to baseline blood pressure levels and ANG II-induced hypertension. Cav3.1, but not Cav3.2, contributes to aldosterone secretion. Aldosterone promotes cardiac hypertrophy during hypertension.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Jennifer L. Dankmeyer ◽  
Randy L. Fast ◽  
Christopher K. Cote ◽  
Patricia L. Worsham ◽  
David Fritz ◽  
...  

The current candidate vaccine againstYersinia pestisinfection consists of two subunit proteins: the capsule protein or F1 protein and the low calcium response V protein or V-antigen. Little is known of the recognition of the vaccine by the host’s innate immune system and how it affects the acquired immune response to the vaccine. Thus, we vaccinated Toll-like receptor (Tlr)2,4, and2/4-double deficient, as well as signal adaptor proteinMyd88-deficient mice. We found that Tlr4 and Myd88 appeared to be required for an optimal immune response to the F1-V vaccine but not Tlr2 when compared to wild-type mice. However, there was a difference between the requirement for Tlr4 and MyD88 in vaccinated animals. When F1-V vaccinatedTlr4mutant (lipopolysaccharide tolerant) andMyd88-deficient mice were challenged by aerosol withY. pestisCO92, all but oneTlr4mutant mice survived the challenge, but no vaccinatedMyd88-deficient mice survived the challenge. Spleens from these latter nonsurviving mice showed thatY. pestiswas not cleared from the infected mice. Our results suggest that MyD88 appears to be important for both an optimal immune response to F1-V and in protection against a lethal challenge ofY. pestisCO92 in F1-V vaccinated mice.


2016 ◽  
Vol 310 (11) ◽  
pp. F1356-F1365 ◽  
Author(s):  
Sebastian Weiss ◽  
Alva Rosendahl ◽  
Daniel Czesla ◽  
Catherine Meyer-Schwesinger ◽  
Rolf A. K. Stahl ◽  
...  

Adaptive and innate immune responses contribute to hypertension and hypertensive end-organ damage. Here, we determined the role of anaphylatoxin C5a, a major inflammatory effector of the innate immune system that is generated in response to complement activation, in hypertensive end-organ damage. For this purpose, we assessed the phenotype of C5a receptor 1 (C5aR1)-deficient mice in ANG II-induced renal and cardiac injury. Expression of C5aR1 on infiltrating and resident renal as well as cardiac cells was determined using a green fluorescent protein (GFP)-C5aR1 reporter knockin mouse. Flow cytometric analysis of leukocytes isolated from the kidney of GFP-C5aR1 reporter mice showed that 28% of CD45-positive cells expressed C5aR1. Dendritic cells were identified as the major C5aR1-expressing population (88.5%) followed by macrophages and neutrophils. Using confocal microscopy, we detected C5aR1 in the kidney mainly on infiltrating cells. In the heart, only infiltrating cells stained C5aR1 positive. To evaluate the role of C5aR1 deficiency in hypertensive injury, an aggravated model of hypertension was used. Unilateral nephrectomy was performed followed by infusion of ANG II (1.5 ng·g−1·min−1) and salt in wild-type ( n = 34) and C5aR1-deficient mice ( n = 32). C5aR1-deficient mice exhibited less renal injury, as evidenced by significantly reduced albuminuria. In contrast, cardiac injury was accelerated with significantly increased cardiac fibrosis and heart weight in C5aR1-deficient mice after ANG II infusion. No effect was found on blood pressure. In summary, the C5a:C5aR1 axis drives end-organ damage in the kidney but protects from the development of cardiac fibrosis and hypertrophy in experimental ANG II-induced hypertension.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Madhu V Singh ◽  
Michael Z Cicha ◽  
Mark W Chapleau ◽  
François M Abboud

We have reported that angiotensin II (Ang II) induces toll-like receptors (TLRs) in the innate immune system. Here we tested which of the two major adaptor proteins of TLRs, the myeloid differentiation protein 88 (MyD88) or the TIR-domain containing adaptor inducing interferon β (TRIF) mediates the Ang II-induced responses. Infusion of Ang II (3000 ng/kg/min) subcutaneously for 3 weeks in WT mice (C57BL/6J) increased systolic blood pressure to a peak value of 147 ± 4 mm Hg and resulted in a 40% increase in heart weight to body weight ratio (HW/BW). Surprisingly, in MyD88-/- mice the pressor response was enhanced significantly to 163 ± 6 mm Hg (P<0.05) and the HW/BW was increased by 60%. Cardiac and renal RNA expression of TNF-α, NOX4 and Type IA -Ang II receptor were also significantly more elevated in MyD88-/- than in WT. In contrast, in a mouse strain with nonfunctional TRIF gene, Trifmut (C57BL/6J-Ticam1Lps2/J), all the Ang II responses were either uniformly decreased or abrogated. We tested whether the enhanced response in MyD88-/- mice represented a phenomenon of ‘Signaling Flux Redistribution” whereby blockade of one signaling pathway (i.e., MyD88) results in a flux of signaling substrates through the alternative pathway (TRIF). We found that expression of the RNA for chemokine CXCL10 which is dependent on TRIF pathway, was significantly enhanced in MyD88-/- hearts. We also found that expression of transcripts for TLR3, TLR4 and the TRIF adaptor protein were all enhanced in MyD88-/- and must have contributed to the exaggerated Ang II response. Conversely, Trifmut had enhanced MyD88 expression. These results suggest that: (1) Ang II induced hypertension, hypertrophy and inflammatory gene expression are primarily mediated by the TRIF pathway and (2) the MyD88 pathway is simultaneously activated by Ang II and exerts a negative regulatory influence on the pressor and inflammatory responses. We conclude that dual activation of two innate immune pathways defines the net response in WT mice with a significant translational potential. Accordingly, impairment of MyD88 may contribute to pathogenesis of hypertension. Conversely, targeting the TRIF pathway may be therapeutic by blocking the inflammatory response and enhancing the negative regulatory effects of MyD88.


Author(s):  
Yuanping Cao ◽  
Qun Wang ◽  
Caiyun Liu ◽  
Wenjun Wang ◽  
Songqing Lai ◽  
...  

Abstract Capn4 belongs to a family of calpains that participate in a wide variety of biological functions, but little is known about the role of Capn4 in cardiac disease. Here, we show that the expression of Capn4 was significantly increased in Angiotensin II (Ang II)-treated cardiomyocytes and Ang II-induced cardiac hypertrophic mouse hearts. Importantly, in agreement with the Capn4 expression patterns, the maximal calpain activity measured in heart homogenates was elevated in Ang II-treated mice, and oral coadministration of SNJ-1945 (calpain inhibitor) attenuated the total calpain activity measured in vitro. Functional assays indicated that overexpression of Capn4 obviously aggravated Ang II-induced cardiac hypertrophy, whereas Capn4 knockdown resulted in the opposite phenotypes. Further investigation demonstrated that Capn4 maintained the activation of the insulin-like growth factor (IGF)-AKT signaling pathway in cardiomyocytes by increasing c-Jun expression. Mechanistic investigations revealed that Capn4 directly bound and stabilized c-Jun, and knockdown of Capn4 increased the ubiquitination level of c-Jun in cardiomyocytes. Additionally, our results demonstrated that the antihypertrophic effect of Capn4 silencing was partially dependent on the inhibition of c-Jun. Overall, these data suggested that Capn4 contributes to cardiac hypertrophy by enhancing the c-Jun-mediated IGF-AKT signaling pathway and could be a potential therapeutic target for hypertrophic cardiomyopathy.


Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Daniel J Fehrenbach ◽  
Meena S Madhur

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.


Hepatology ◽  
2004 ◽  
Vol 40 (2) ◽  
pp. 434-441 ◽  
Author(s):  
Zhiping Li ◽  
Jude A. Oben ◽  
Shiqi Yang ◽  
Huizhi Lin ◽  
Elizabeth A. Stafford ◽  
...  

Author(s):  
Xiao Chun Li ◽  
Ana Paula Oliveira Leite ◽  
Xiaowen Zheng ◽  
Chunling Zhao ◽  
Xu Chen ◽  
...  

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.


2021 ◽  
Author(s):  
Ding Xiaoli ◽  
Yuan Qingqing ◽  
Qian Haibing

Abstract Background: Myocardial hypertrophy occurs in many cardiovascular diseases. Leonurine (Leo) is commonly used for cardiovascular and cerebrovascular diseases. However, whether it can prevent cardiac hypertrophy is not known. The aim of this study was to investigate the effect and mechanism of Leonurine (Leo) against pressure-overload cardiac hypertrophy induced by abdominal aortic constriction (AAC) in rats. Methods: To answer this question, we prove it in the following way: Cardiac function was evaluated by hemodynamic; the left ventricle enlargement was measured by heart weight index (HWI) and left ventricular mass index (LVWI); myocardial tissue changes and myocardial cell diameter (MD) were determined by Hematoxylin and eosin (HE) staining; theβ-myosin heavy chain(β-MHC)and atrial natriuretic factor (ANF), which are recognized as a marker of cardiac hypertrophy, were determined by Real-time quantitative PCR (qRT-PCR), then another gene phospholipase C (PLC), inositol triphosphate (IP3), which associated with RAS were determined by Western blot(WB). angiotensin II (Ang II), angiotensin II type 1 receptor (AT1R) were determined by ELISA, WB and qRT-PCR methods. Finally, we measured the level of Ca2+ by microplate method and the protooncogene c-fos and c-myc mRNA in left ventricular myocardium by qRT-PCR.Results: Compare with control group, Leonurine can improve systolic dysfunction; inhibit the increase of left cardiac; inhibit myocardial cells were abnormally large and restrain the changes of cardiac histopathology; decrease the expression of β-MHC, ANF, Ang II, AT1R, c-fos and c-myc mRNA and the protein levels of PLC, IP3, AngII and AT1R in left ventricular myocardium, in addition, the content of Ca2+ also decrease. Conclusion: Therefore, Leonurine can inhibit cardiac hypertrophy induced by AAC and its effects may be associated with RAS.


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