Modulation of Angiotensin II-Induced Cellular Hypertrophy by Cannflavin-C: Unveiling the Impact on Cytochrome P450 1B1 and Arachidonic Acid Metabolites.

This research aimed to clarify the impacts of cannflavin-C on angiotensin II (Ang II)-induced cardiac hypertrophy and their potential role in modulating cytochrome P450 1B1 (CYP1B1) and arachidonic acid (AA) metabolites. Currently there is no evidence to suggest that cannflavin-C, a prenylated flavonoid, has any significant effects on the heart or cardiac hypertrophy. The metabolism of arachidonic acid (AA) into midchain hydroxyeicosatetraenoic acids (HETEs), facilitated by CYP1B1 enzyme, plays a role in the development of cardiac hypertrophy, which is marked by enlarged cardiac cells. Adult human ventricular cardiomyocyte (AC16) cell line was cultured and exposed to cannflavin-C in the presence and absence of Ang II. The assessment of mRNA expression pertaining to cardiac hypertrophic markers and cytochromes P450 (P450s) was conducted via real-time polymerase chain reaction (PCR), whereas the quantification of P450 protein levels was carried out through western blot analysis. Ang II induced hypertrophic markers myosin heavy chain (ß/α-MHC), atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) and increased cell surface area, whereas cannflavin-C mitigated these effects. Gene and protein expression analysis revealed that cannflavin-C downregulated CYP1B1 gene expression, protein level, and enzyme activity assessed by 7-methoxyresorufin O-deethylase (MROD). Arachidonic acid metabolites analysis, using liquid chromatography-tandem mass spectrometry (LC-MS/MS), demonstrated that Ang II increased midchain (R/S)-HETE concentrations, which were attenuated by cannflavin-C. This study provides novel insights into the potential of cannflavin-C in modulating arachidonic acid metabolites and attenuating Ang II-induced cardiac hypertrophy, highlighting the importance of this compound as potential therapeutic agents for cardiac hypertrophy. SIGNIFICANCE STATEMENT: This study demonstrates that cannflavin-C offers protection against cellular hypertrophy induced by angiotensin II. The significance of this research lies in its novel discovery, which elucidates a mechanistic pathway involving the inhibition of CYP1B1 by cannflavin-C. This discovery opens up new avenues for leveraging this compound in the treatment of heart failure.

CD4+ T-Cell Legumain Deficiency Attenuates Hypertensive Damage via Preservation of TRAF6.

BACKGROUND: T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of hypertension remains unclear. METHODS: Peripheral blood samples were collected from patients with hypertension, and cluster of differentiation (CD)4+ T cells were sorted for gene expression and Western blotting analysis. TLGMNKO (T cell-specific LGMN-knockout) mice (Lgmnf/f/CD4Cre), regulatory T cell (Treg)-specific LGMN-knockout mice (Lgmnf/f/Foxp3YFP Cre), and RR-11a (LGMN inhibitor)-treated C57BL/6 mice were infused with Ang II (angiotensin II) or deoxycorticosterone acetate/salt to establish hypertensive animal models. Flow cytometry, 4-dimensional label-free proteomics, coimmunoprecipitation, Treg suppression, and in vivo Treg depletion or adoptive transfer were used to delineate the functional importance of T-cell LGMN in hypertension development. RESULTS: LGMN mRNA expression was increased in CD4+ T cells isolated from hypertensive patients and mice, was positively correlated with both systolic and diastolic blood pressure, and was negatively correlated with serum IL (interleukin)-10 levels. TLGMNKO mice exhibited reduced Ang II-induced or deoxycorticosterone acetate/salt-induced hypertension and target organ damage relative to wild-type (WT) mice. Genetic and pharmacological inhibition of LGMN blocked Ang II-induced or deoxycorticosterone acetate/salt-induced immunoinhibitory Treg reduction in the kidneys and blood. Anti-CD25 antibody depletion of Tregs abolished the protective effects against Ang II-induced hypertension in TLGMNKO mice, and LGMN deletion in Tregs prevented Ang II-induced hypertension in mice. Mechanistically, endogenous LGMN impaired Treg differentiation and function by directly interacting with and facilitating the degradation of TRAF6 (tumor necrosis factor receptor-associated factor 6) via chaperone-mediated autophagy, thereby inhibiting NF-κB (nuclear factor kappa B) activation. Adoptive transfer of LGMN-deficient Tregs reversed Ang II-induced hypertension, whereas depletion of TRAF6 in LGMN-deficient Tregs blocked the protective effects. CONCLUSIONS: LGMN deficiency in T cells prevents hypertension and its complications by promoting Treg differentiation and function. Specifically targeting LGMN in Tregs may be an innovative approach for hypertension treatment.

Early-life exposure to lead changes cardiac development and compromises long-term cardiac function.

Lead (Pb) is widely used in industrial and daily-use consumer products. Early-life exposure may increase the risk of lead-related heart problems in childhood. However, the effects of early-life lead exposure on fetal heart development and long-term cardiac outcomes are unknown. In this study, pregnant ICR mice were exposed to lead acetate trihydrate (50 mg/kg/d) via oral gavage from gestation day 1.5 until offspring weaning. Thereafter, the second hit model was established, two groups of offspring (4 weeks old) were either administered sterile saline or Angiotensin II (Ang II) for 4 weeks until euthanasia. We investigated lead-induced offspring heart damage from embryonic period to adulthood by echocardiographic analysis, pathological H&E staining, and ultrastructural examination, as well as mitochondrial function detection. The results showed early-life lead exposure predisposed offspring mice to decreased ejection fraction, increased left ventricular volume, accompanied by hypertrophy and dilation, cardiomyocyte sarcomere dysplasia, abnormal mitochondrial structure, mitochondrial dysfunction, and decreased expression of key sarcomeric and mitochondrial genes, rendering them more susceptible to cardiac hypertrophy, vascular wall thickening, cardiac fibrosis, apoptosis, and heart failure induced by Ang II infusion. This study elucidates early-life low dose lead exposure compromises cardiac development and exacerbates second hit-induced cardiac pathological responses in adulthood, which furnishes crucial scientific evidence pertaining to the cardiac toxicity and risk evaluation associated with early-life exposure to lead.

The novel peptide athycaltide-1 attenuates Ang II-induced pathological myocardial hypertrophy by reducing ROS and inhibiting the activation of CaMKII and ERK1/2.

Pathological myocardial hypertrophy initially develops as an adaptive response to cardiac stress, which can be induced by many diseases. It is accompanied by adverse cardiovascular events, including heart failure, arrhythmias, and death. The purpose of this research was to explore the molecular mechanism of a novel peptide Athycaltide-1 (ATH-1) in the treatment of Ang II-induced pathological myocardial hypertrophy. In this study, the mRNA of Control group, Ang II group, ATH-1 group and Losartan group mice were sequenced by high-throughput sequencing technology. The results showed that the differentially expressed genes (DEGs) were significantly enriched in cell response to oxidative stress, regulation of reactive oxygen species metabolism and calmodulin binding. Then, the oxidation level of mouse hearts and H9c2 cardiomyocytes in each group and the expression of key proteins of CaMKII/HDAC/MEF2C and ERK1/2 signaling pathways were detected to preliminarily verify the positive effect of ATH-1. At the same time, the effect of ATH-1 was further determined by adding reactive oxygen species (ROS) inhibitor N-acetylcysteine (NAC) and CaMKII inhibitor AIP in vitro. The results showed that ATH-1 could significantly reduce the level of oxidative stress in hypertrophic cardiomyocytes and inhibiting the activation of CaMKII and ERK1/2.

Losartan impairs HTR-8/SVneo trophoblast migration through inhibition of angiotensin II-induced pro-inflammatory profile in human endometrial stromal cells.

A deep interaction between the endometrium and the invading trophoblast occurs during implantation in humans, with the acquisition of uterine receptivity to the invading embryo promoted by an elevation of pro-inflammatory cytokines in the endometrium, and the invasiveness of decidualizing endometrial stromal cells, augmented by trophoblast-derived signals. Considering that usage of angiotensin II type 1 (AT1) receptor blockers, among other renin-angiotensin system (RAS) antagonists, is associated with adverse pregnancy outcomes, here we aim to analyse the involvement of AT1 receptor in the reciprocal dialogue occurring between endometrial stroma and trophoblast cells. In human endometrial stromal cells (T-HESC) pre-incubated with a decidualization cocktail, angiotensin (Ang) II increased protein expression of prolactin and FOXO1, markers of endometrial decidualization, while promoting nuclear translocation of FOXO1. In addition, Ang II treatment increased CXCL8, and matrix metalloprotease (MMP)-2 levels in T-HESC. Incubation with the AT1 receptor blocker losartan or with an NFAT signalling inhibitor, decreased Ang II-induced secretion of prolactin, CXCL8, and MMP-2 in T-HESC. In a wound healing assay, conditioned medium (CM) obtained from Ang II-treated T-HESC, but not CM from losartan-pre-incubated T-HESC, increased migration of HTR-8/SVneo trophoblasts, effect that was inhibited in the presence of a CXCL8-neutralizing antibody. An increased secretion of CXCL8 and MMP-2 was observed after treatment of T-HESC with CM obtained from HTR-8/SVneo cells, which was not observed in T-HESC pre-incubated with losartan or with the NFAT inhibitor. This study evidenced a reciprocal RAS-coded messaging between trophoblast and ESC which is affected by the AT1 receptor blocker losartan.

Homeostatic, Non-Canonical Role of Macrophage Elastase in Vascular Integrity.

BACKGROUND: Matrix metalloproteinase (MMP)-12 is highly expressed in abdominal aortic aneurysms and its elastolytic function has been implicated in the pathogenesis. This concept is challenged, however, by conflicting data. Here, we sought to revisit the role of MMP-12 in abdominal aortic aneurysm. METHODS: Apoe-/- and Mmp12-/-/Apoe-/- mice were infused with Ang II (angiotensin). Expression of neutrophil extracellular traps (NETs) markers and complement component 3 (C3) levels were evaluated by immunostaining in aortas of surviving animals. Plasma complement components were analyzed by immunoassay. The effects of a complement inhibitor, IgG-FH1-5 (factor H-immunoglobulin G), and macrophage-specific MMP-12 deficiency on adverse aortic remodeling and death from rupture in Ang II-infused mice were determined. RESULTS: Unexpectedly, death from aortic rupture was significantly higher in Mmp12-/-/Apoe-/- mice. This associated with more neutrophils, citrullinated histone H3 and neutrophil elastase, markers of NETs, and C3 levels in Mmp12-/- aortas. These findings were recapitulated in additional models of abdominal aortic aneurysm. MMP-12 deficiency also led to more pronounced elastic laminae degradation and reduced collagen integrity. Higher plasma C5a in Mmp12-/- mice pointed to complement overactivation. Treatment with IgG-FH1-5 decreased aortic wall NETosis and reduced adverse aortic remodeling and death from rupture in Ang II-infused Mmp12-/- mice. Finally, macrophage-specific MMP-12 deficiency recapitulated the effects of global MMP-12 deficiency on complement deposition and NETosis, as well as adverse aortic remodeling and death from rupture in Ang II-infused mice. CONCLUSIONS: An MMP-12 deficiency/complement activation/NETosis pathway compromises aortic integrity, which predisposes to adverse vascular remodeling and abdominal aortic aneurysm rupture. Considering these new findings, the role of macrophage MMP-12 in vascular homeostasis demands re-evaluation of MMP-12 function in diverse settings.

Catalpol relieved angiotensin II-induced blood-brain barrier destruction via inhibiting the TLR4 pathway in brain endothelial cells.

CONTEXT: Catalpol is a major bioactive constituent of Rehmannia glutinosa Libosch (Scrophulariaceae), a traditional Chinese medicine, which is widely used in multiple diseases, including hypertension. OBJECTIVES: To explore whether catalpol protects against angiotensin II (Ang II)-triggered blood-brain barrier (BBB) leakage. MATERIALS AND METHODS: The bEnd.3 cells and BBB models were pre-treated with or without catalpol (50, 200 and 500 µM) or TAK-242 (1 µM) for 2 h and then with Ang II (0.1 µM) or LPS (1 µg/mL) for 24 h. Cell viability was determined by the MTT assay. The levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), inducible nitric oxide synthase (iNOS), tumour necrosis factor-α (TNF-α), caveolin-1 (Cav-1) and p-eNOS/eNOS were tested by western blot. The BBB permeability was evaluated by the flux of bovine serum albumin-fluorescein isothiocyanate (BSA-FITC) across monolayers. nuclear factor kappa-B (NF-κB) p65 nuclear translocation was explored by immunofluorescence staining. RESULTS: Ang II (0.1 µM) decreased the cell viability to 86.52 ± 1.79%, elevated the levels of TLR4, MyD88, iNOS, TNF-α and Cav-1 respectively to 3.7-, 1.5-, 2.3-, 2.2- and 2.7-fold, reduced the level of p-eNOS/eNOS to 1.6-fold in bEnd.3 cells, and eventually increased BBB permeability. Catalpol dose-dependently reversed these changes at 50-500 µM. Meanwhile, catalpol (500 µM) inhibited the upregulated levels of TLR4 pathway-related proteins and NF-κB p65 nuclear translocation, decreased the enhanced transcytosis, and relieved the BBB disruption caused by both LPS (the TLR4 activator) and Ang II. The effects are same as TAK-242 (the TLR4 inhibitor). CONCLUSIONS: Catalpol relieved the Ang II-induced BBB damage, which indicated catalpol has high potential for the treatment of hypertension-induced cerebral small vessel disease (cSVD).

Qingda granule alleviate angiotensin â ±-induced hypertensive renal injury by suppressing oxidative stress and inflammation through NOX1 and NF-κB pathways.

Hypertension has become one of the important diseases harmful to human health. In China, Qingda granule (QDG) has been used to treat hypertension for decades. Previous studies by our team have shown that oxidative stress may be one of the pathways through which QDG inhibits hypertension-induced organs injury. However, the specific molecular mechanism of its anti-hypotension and renal oxidative stress response were unclearly. This study investigated QDG's potential protective mechanism against hypertension-induced renal injury. Mice were infused with Angiotensin Ⅱ (Ang Ⅱ, 500 ng/kg/min) or equivalent saline solution (Control) and administered oral QDG (1.145 g/kg/day) or saline for four weeks. QDG treatment mitigated the elevated blood pressure and reduced renal pathological changes induced by Ang Ⅱ. As per the RNA sequencing results, QDG affects oxidative stress signaling. In agreement with these findings, QDG significantly attenuated the Ang Ⅱ-induced increase in Nitrogen oxides 1 (NOX1) and reactive oxygen species and the decrease in superoxide dismutase in renal tissue. Additionally, QDG significantly inhibited Interleukin 6 (IL-6), Tumor necrosis factor α (TNF-α), and Interleukin 1ß (IL-1ß) expression in renal tissues and blocked the phosphorylation of P65 (NF-κB subunit) and IκB. These results were confirmed in vitro. Overall, QDG reduced Ang Ⅱ-induced elevated blood pressure and renal injury by inhibiting oxidative stress and inflammation caused by NOX1 and NF-κB pathways. The results of this study provide an experimental basis for the clinical application of QDG, and to open up a new direction for the clinical treatment of hypertension.

Small ubiquitin-related modifier (SUMO)ylation of SIRT1 mediates (-)-epicatechin inhibited- differentiation of cardiac fibroblasts into myofibroblasts.

CONTEXT: (-)-Epicatechin (EPI) is a crucial substance involved in the protective effects of flavanol-rich foods. Previous studies have indicated EPI has a cardioprotective effect, but the molecular mechanisms in inhibition of cardiac fibrosis are unclear. OBJECTIVE: We evaluated the effect of EPI in preventing cardiac fibrosis and the underlying molecular mechanism related to the SIRT1-SUMO1/AKT/GSK3ß pathway. MATERIALS AND METHODS: Cardiac fibrosis mice model was established with transaortic constriction (TAC). Male C57BL/6 mice were randomly separated into 4 groups. Mice received 1 mg/kg/day of EPI or vehicle orally for 4 weeks. The acutely isolated cardiac fibroblasts were induced to myofibroblasts with 1 µM angiotensin II (Ang II). The cardiac function was measured with the ultrasonic instrument. Histological analysis of mice's hearts was determined with H&E or Masson method. The protein level of fibrosis markers, SUMOylation of SIRT1, and AKT/GSK3ß pathway were quantified by immunofluorescence and western blot. RESULTS: EPI treatment (1 mg/kg/day) could reverse the TAC-induced decline in LVEF (TAC, 61.28% ± 1.33% vs. TAC + EPI, 74.00% ± 1.64%), LVFS (TAC, 28.16% ± 0.89% vs. TAC + EPI, 37.18% ± 1.29%). Meantime, we found that 10 µM EPI blocks Ang II-induced transformation of cardiac fibroblasts into myofibroblasts. The underlying mechanism of EPI-inhibited myofibroblasts transformation involves activation of SUMOylation of SIRT1 through SP1. Furthermore, SUMOylation of SIRT1 inhibited Ang II-induced fibrogenic effect via the AKT/GSK3ß pathway. CONCLUSION: EPI plays a protective effect on cardiac fibrosis by regulating the SUMO1-dependent modulation of SIRT1, which provides a theoretical basis for use in clinical therapies.

mTOR inhibition prevents angiotensin II-induced aortic rupture and pseudoaneurysm but promotes dissection in Apoe-deficient mice.

Aortic dissection and rupture are triggered by decreased vascular wall strength and/or increased mechanical loads. We investigated the role of mTOR signaling in aortopathy using a well-described model of angiotensin II-induced dissection, aneurysm, or rupture of the suprarenal abdominal aorta in Apoe-deficient mice. Although not widely appreciated, nonlethal hemorrhagic lesions present as pseudoaneurysms without significant dissection in this model. Angiotensin II-induced aortic tears result in free rupture, contained rupture with subadventitial hematoma (forming pseudoaneurysms), dilatation, or healing, while the media invariably thickens regardless of mural tears. Medial thickening results from smooth muscle cell hypertrophy and extracellular matrix accumulation, including matricellular proteins. Angiotensin II activates mTOR signaling in vascular wall cells, and inhibition of mTOR signaling by rapamycin prevents aortic rupture but promotes dissection. Decreased aortic rupture correlates with decreased inflammation and metalloproteinase expression, whereas extensive dissection correlates with induction of matricellular proteins that modulate adhesion of vascular cells. Thus, mTOR activation in vascular wall cells determines whether aortic tears progress to dissection or rupture. Previous mechanistic studies of aortic aneurysm and dissection by angiotensin II in Apoe-deficient mice should be reinterpreted as clinically relevant to pseudoaneurysms, and mTOR inhibition for aortic disease should be explored with caution.

Phosphodiesterase 4D promotes angiotensin II-induced hypertension in mice via smooth muscle cell contraction.

Hypertension is a common chronic disease, which leads to cardio-cerebrovascular diseases, and its prevalence is increasing. The cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway participates in multiple cardiovascular diseases. Phosphodiesterase (PDE) 4 has been shown to regulate PKA activity via cAMP specific hydrolysis. However, whether PDE4-cAMP-PKA pathway influences hypertension remains unknown. Herein, we reveal that PDE4D (one of PDE4 isoforms) expression is upregulated in the aortas of experimental hypertension induced by angiotensin II (Ang II). Furthermore, knockout of Pde4d in mouse smooth muscle cells (SMCs) attenuates Ang II-induced hypertension, arterial wall media thickening, vascular fibrosis and vasocontraction. Additionally, we find that PDE4D deficiency activates PKA-AMP-activated protein kinase (AMPK) signaling pathway to inhibit myosin phosphatase targeting subunit 1 (MYPT1)-myosin light chain (MLC) phosphorylation, relieving Ang II-induced SMC contraction in vitro and in vivo. Our results also indicate that rolipram, a PDE4 inhibitor, may be a potential drug for hypertension therapy.

Characterization of a murine model of endothelial dysfunction induced by chronic intraperitoneal administration of angiotensin II.

Endothelial dysfunction (ED) is a key factor for the development of cardiovascular diseases. Due to its chronic, life-threatening nature, ED only can be studied experimentally in animal models. Therefore, this work was aimed to characterize a murine model of ED induced by a daily intraperitoneal administration of angiotensin II (AGII) for 10 weeks. Oxidative stress, inflammation, vascular remodeling, hypertension, and damage to various target organs were evaluated in treated animals. The results indicated that a chronic intraperitoneal administration of AGII increases the production of systemic soluble VCAM, ROS and ICAM-1 expression, and the production of TNFα, IL1ß, IL17A, IL4, TGFß, and IL10 in the kidney, as well as blood pressure levels; it also promotes vascular remodeling and induces non-alcoholic fatty liver disease, glomerulosclerosis, and proliferative retinopathy. Therefore, the model herein proposed can be a representative model for ED; additionally, it is easy to implement, safe, rapid, and inexpensive.

Ang II-Induced Hypertension Exacerbates the Pathogenesis of Tuberculosis.

It has been known that infection plays a role in the development of hypertension. However, the role of hypertension in the progression of infectious diseases remain unknown. Many countries with high rates of hypertension show geographical overlaps with those showing high incidence rates of tuberculosis (TB). To explore the role of hypertension in tuberculosis, we compared the effects of hypertension during mycobacterial infection, we infected both hypertensive Angiotensin II (Ang II) and control mice with Mycobacterium tuberculosis (Mtb) strain H37Ra by intratracheal injection. Ang II-induced hypertension promotes cell death through both apoptosis and necrosis in Mtb H37Ra infected mouse lungs. Interestingly, we found that lipid accumulation in pulmonary tissues was significantly increased in the hypertension group compared to the normal controls. Ang II-induced hypertension increases the formation of foamy macrophages during Mtb infection and it leads to cell death. Moreover, the hypertension group showed more severe granuloma formation and fibrotic lesions in comparison with the control group. Finally, we observed that the total number of mycobacteria was increased in the lungs in the hypertension group compared to the normal controls. Taken together, these results suggest that hypertension increases intracellular survival of Mtb through formation of foamy macrophages, resulting in severe pathogenesis of TB.

Defective autophagy in vascular smooth muscle cells enhances the healing of abdominal aortic aneurysm.

Autophagy is an evolutionarily conserved cellular catabolic process essential for cell homeostasis, and thus its failure is associated with several diseases. While autophagy has been reported to play a role in vascular smooth muscle cells (SMCs) in vascular disorders, its precise role in the pathogenesis of abdominal aortic aneurysm (AAA) has not yet been elucidated. In this study, we investigated the role of SMC autophagy in AAA formation. As a mouse model of AAA, we used control apolipoprotein E-deficient (apoeKO) mice and Atg7cKO (SMC-specific Atg7-deficient mice):apoeKO mice administered angiotensin II for 4 weeks. Intriguingly, Kaplan-Meier curves showed that the survival rates of Atg7cKO:apoeKO mice were significantly higher than those of apoeKO mice. The hematoma area in AAA of Atg7cKO:apoeKO mice was smaller than in apoeKO mice despite the lack of a significant difference in AAA incidence between the two groups. Furthermore, the amount of granulomatous tissues was significantly larger and the collagen-positive area within AAA was significantly larger in Atg7cKO:apoeKO mice than in apoeKO mice. In accordance with these findings, SMCs cultured from Atg7cKO mice showed increased expression of collagens, independent of angiotensin II action. Taken together, our data suggest that defective autophagy in SMCs elicits AAA healing that may underlie the better survival rate under dyslipidemia and angiotensin II infusion.

Angiotensin II-induced renal angiotensinogen formation is enhanced in mice lacking tumor necrosis factor-alpha type 1 receptor.

In hypertension induced by angiotensin II (AngII) administration with high salt (HS) intake, intrarenal angiotensinogen (AGT) and tumor necrosis factor-alpha (TNF-α) levels increase. However, TNF-α has been shown to suppress AGT formation in cultured renal proximal tubular cells. We examined the hypothesis that elevated AngII levels during HS intake reduces TNF-α receptor type 1 (TNFR1) activity in the kidneys, thus facilitating increased intrarenal AGT formation. The responses to HS diet (4% NaCl) with chronic infusion of AngII (25 ng/min) via implanted minipump for 4 weeks were assessed in wild-type (WT) and knockout (KO) mice lacking TNFR1 or TNFR2 receptors. Blood pressure was measured by tail-cuff plethysmography, and 24-h urine samples were collected using metabolic cages prior to start (0 day) and at the end of 2nd and 4th week periods. The urinary excretion rate of AGT (uAGT; marker for intrarenal AGT) was measured using ELISA. HS +AngII treatment for 4 weeks increased mean arterial pressure (MAP) in all strains of mice. However, the increase in MAP in TNFR1KO (77 ± 2 to 115 ± 3 mmHg; n = 7) was significantly greater (p < 0.01) than in WT (76 ± 1 to 102 ± 2 mmHg; n = 7) or in TNFR2KO (78 ± 2 to 99 ± 5 mmHg; n = 6). The increase in uAGT at 4th week was also greater (p < 0.05) in TNFR1KO mice (6 ± 2 to 167 ± 75 ng/24 h) than that in WT (6 ± 3 to 46 ± 16 ng/24 h) or in TNFR2KO mice (8 ± 7 to 65 ± 44 ng/24 h). The results indicate that TNFR1 exerts a protective role by mitigating intrarenal AGT formation induced by elevated AngII and HS intake.

Angiotensin II-induced natriuresis is attenuated in knockout mice lacking the receptors for tumor necrosis factor-α.

Intravenous infusion of relatively higher doses of angiotensin II (AngII) elicits natriuresis as opposed to its usual anti-natruretic response. As AngII can induce tumor necrosis factor-α (TNFα) production which elicits natriuresis via its action on TNFα receptor type 1 (TNFR1), we hypothesize that the concomitant release of TNFα contributes to the natriuretic response to AngII. Responses to AngII infusion (1 ng min-1  g-1 for 75 min, iv) were evaluated in anesthetized knockout (KO) mice lacking TNFR1 (n = 6) and TNFR2 (TNFα receptor type 2; n = 6) and compared these responses with those in wild type (WT; n = 6) mice. Arterial pressure (AP) was recorded from a cannula placed in the carotid artery. Renal blood flow (RBF) and glomerular filtration rate (GFR) were measured by PAH and inulin clearances, respectively. Urine was collected from a catheter placed in the bladder. AngII caused similar increases (p < 0.05 vs basal values) in AP (WT, 37 ± 5%; TNFR1KO, 35 ± 4%; TNFR2KO, 30 ± 4%) and decreases (p < 0.05) in RBF (WT, -39 ± 5%; TNFR1KO, -28 ± 6%; TNFR2KO, -31 ± 4%) without significant changes in GFR (WT, -17 ± 7%; TNFR1KO, -18 ± 7%; TNFR2KO, -12 ± 7%). However, despite similar changes in AP and renal hemodynamics, AngII induced increases (p < 0.05) in urinary sodium excretion in WT (3916 ± 942%) were less in the KO strains, more or less in TNFR1KO (473 ± 170%) than in TNFR2KO (1176 ± 168%). These data indicate that TNF-α receptors, particularly TNFR1 are involved in the natriuretic response that occur during acute infusion of AngII and thus, plays a protective role in preventing excessive salt retention at clinical conditions associated with elevated AngII level.

Liquiritigenin attenuates isoprenaline­induced myocardial fibrosis in mice through the TGF­ß1/Smad2 and AKT/ERK signaling pathways.

Myocardial fibrosis is a pathological process characterized by excessive accumulation of extracellular matrix in myocardial interstitial spaces. Myocardial fibrosis is a fundamental process in ventricular remodeling and a primary contributor to the progression of heart failure. Liquiritigenin (LQ) is a flavanone compound with anti­oxidative, anti­carcinogenic, anti­inflammatory and estrogenic properties. The present study aimed to investigate the regulatory potential of LQ treatment in a mouse model of isoprenaline (ISO)­induced cardiac fibrosis and in cultured H9C2 cardiomyocytes stimulated with angiotensin II (Ang II). The treatment of ISO­induced mice with LQ significantly decreased the levels of cardiac injury­related proteins in the serum and ECM accumulation in mouse heart tissues. LQ treatment also effectively alleviated cardiac dysfunction in ISO­treated mice. Further analyses revealed that LQ inhibited ISO­induced collagen formation and activation of the transforming growth factor­ß1 (TGF­ß1)/Smad2 and protein kinase B (AKT)/extracellular signal­regulated kinase (ERK) signaling pathways. As a major pathological event in myocardial fibrosis, the apoptosis of cardiomyocytes has been considered a key mechanism contributing to impaired left ventricle performance. The pretreatment of rat cardiomyocytes with LQ significantly reduced the apoptosis of H9C2 cells, and inhibited Ang II­induced activation of the TGF­ß1/Smad2 and AKT/ERK pathways. In conclusion, the present study revealed that LQ ameliorated ISO­induced myocardial fibrosis in mice and inhibited the apoptosis of cardiomyocytes in vitro by inhibiting the TGF­ß1/Smad2 and AKT/ERK signaling pathways. These results suggested the anti­fibrotic and cardioprotective potential of LQ in fibrosis, thus supporting the use of LQ for the management of cardiomyocyte injury and myocardial fibrosis in patients with cardiac diseases.

Cyclic nucleotide phosphodiesterase 1C contributes to abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is characterized by aorta dilation due to wall degeneration, which mostly occurs in elderly males. Vascular aging is implicated in degenerative vascular pathologies, including AAA. Cyclic nucleotide phosphodiesterases, by hydrolyzing cyclic nucleotides, play critical roles in regulating vascular structure remodeling and function. Cyclic nucleotide phosphodiesterase 1C (PDE1C) expression is induced in dedifferentiated and aging vascular smooth muscle cells (SMCs), while little is known about the role of PDE1C in aneurysm. We observed that PDE1C was not expressed in normal aorta but highly induced in SMC-like cells in human and murine AAA. In mouse AAA models induced by Angiotensin II or periaortic elastase, PDE1C deficiency significantly decreased AAA incidence, aortic dilation, and elastin degradation, which supported a causative role of PDE1C in AAA development in vivo. Pharmacological inhibition of PDE1C also significantly suppressed preestablished AAA. We showed that PDE1C depletion antagonized SMC senescence in vitro and/or in vivo, as assessed by multiple senescence biomarkers, including senescence-associated ß-galactosidase activity, γ-H2AX foci number, and p21 protein level. Interestingly, the role of PDE1C in SMC senescence in vitro and in vivo was dependent on Sirtuin 1 (SIRT1). Mechanistic studies further showed that cAMP derived from PDE1C inhibition stimulated SIRT1 activation, likely through a direct interaction between cAMP and SIRT1, which leads to subsequent up-regulation of SIRT1 expression. Our findings provide evidence that PDE1C elevation links SMC senescence to AAA development in both experimental animal models and human AAA, suggesting therapeutical significance of PDE1C as a potential target against aortic aneurysms.

The Cancer Therapy-Related Clonal Hematopoiesis Driver Gene Ppm1d Promotes Inflammation and Non-Ischemic Heart Failure in Mice.

[Figure: see text].

Macrophage depletion protects against endothelial dysfunction and cardiac remodeling in angiotensin II hypertensive mice.

Objective: Hypertension is associated with a low-grade systemic inflammation in cardiovascular system. Macrophage infiltration may initiate an inflammatory process that contributes to vascular and ventricular remodeling in hypertensive human and mice. The present study investigated the effect of chemical depletion of macrophage using liposome encapsulated clodronate (LEC) on cardiac hypertrophy and remodeling in angiotensin (Ang) II hypertensive mice.Methods: C57BL/6 mice received an Ang II (1.1 mg/kg/day with a minipump) infusion for 2 weeks to induce hypertension. Endothelium-dependent relaxation (ED) was examined by organ bath, hematoxylin and staining and Masson-Trichrome staining were used to evaluate aorta and cardiac hypertrophy and fibrosis.Results: Ang II infusion significantly increased systolic blood pressure (SBP), cardiac hypertrophy and fibrosis, and impaired EDR accompanied by increased macrophage infiltration in the heart. Treatment with LEC significantly lowered Ang II-induced cardiac hypertrophy and fibrosis and cardiac macrophage infiltration, and improved EDR with a mild reduction in SBP. Ang II increased the expression of inflammatory cytokines tumor necross factor alpha and interleukin 1 beta and profibrotic factors transforming growth factor beta 1 and fibronectin in the heart, with was reduced by LEC treatment. Treatment with LEC prevented Ang II-induced the phosphorphorylation of ERK1/2 and c-Jun-N-terminal kinase.Conclusions: Our study suggests that cardiac macrophage may be critical for hypertensive cardiac hypertrophy and remodeling, the underlying mechanisms may involve initial heart inflammation and the activation of hypertrophic MAPKs pathway.