OBJECTIVE: To identify whether naringenin plays a protective role during thoracic aneurysm formation in Marfan syndrome. METHODS: To validate the effect of naringenin, Fbn1^C1039G/+ mice, the mouse model of Marfan syndrome, were fed with naringenin, and the disease progress was evaluated. The molecular mechanism of naringenin was further investigated via in vitro studies, such as bioluminescence resonance energy transfer (BRET), atomic force microscope and radioligand receptor binding assay. RESULTS: Six-week-old Fbn1^C1039G/+ mice were fed with naringenin for 20 weeks. Compared with the control group, naringenin significantly suppressed the aortic expansion [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.49±0.47) mm, n=18 vs. (1.87±0.19) mm, n=22, P < 0.05], the degradation of elastin, and the expression and activity of matrix metalloproteinase 2 (MMP2) and MMP9 in the ascending aorta of Fbn1^C1039G/+ mice. Besides, treatment with naringenin for 6 weeks also attenuated the disease progress among the 20-week-old Fbn1^C1039G/+ mice with established thoracic aortic aneurysms [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.24±0.23) mm, n=8 vs. (1.90±0.17) mm, n=8, P < 0.05]. To understand the underlying molecular mechanisms, we examined the effects of naringenin on angiotensin Ⅱ type 1 receptor (AT1) signaling and transforming growth factor-β (TGF-β) signaling respectively, which were the dominant signaling pathways contributing to aortopathy in Marfan syndrome as previously reported. The results showed that naringenin decreased angiotensin Ⅱ (Ang Ⅱ)-induced phosphorylation of protein kinase C (PKC) and extracellular regulating kinase 1/2 (ERK1/2) in HEK293A cell overexpressing AT1 receptor. Moreover, naringenin inhibited Ang Ⅱ-induced calcium mobilization and uclear factor of activated T-cells (NFAT) signaling. The internalization of AT1 receptor and its binding to β-arrestin-2 with Ang Ⅱ induction were also suppressed by naringenin. As evidenced by atomic force microscope and radioligand receptor binding assay, naringenin inhibited Ang Ⅱ binding to AT1 receptor. In terms of TGF-β signaling, we found that feeding the mice with naringenin decreased the phosphorylation of Smad2 and ERK1/2 as well as the expression of TGF-β downstream genes. Besides, the serum level of TGF-β was also decreased by naringenin in the Fbn1^C1039G/+ mice. Furthermore, we detected the effect of naringenin on platelet, a rich source of TGF-β, both in vivo and in vitro. And we found that naringenin markedly decreased the TGF-β level by inhibiting the activation of platelet. CONCLUSION Our study showed that naringenin has a protective effect on thoracic aortic aneurysm formation in Marfan syndrome by suppressing both AT1 and TGF-β signaling.
Angiotensin II/metabolism* ; Animals ; Aortic Aneurysm, Thoracic/prevention & control* ; Calcium/metabolism* ; Disease Models, Animal ; Elastin/metabolism* ; Fibrillin-1/metabolism* ; Flavanones ; Marfan Syndrome/metabolism* ; Matrix Metalloproteinase 2 ; Matrix Metalloproteinase 9 ; Mice ; Mice, Inbred C57BL ; Protein Kinase C/metabolism* ; Receptor, Angiotensin, Type 1/metabolism* ; Transforming Growth Factor beta/metabolism* ; Transforming Growth Factors/metabolism* ; beta-Arrestins/metabolism*

BACKGROUND: Macrophages are involved in the pathogenesis of idiopathic pulmonary fibrosis, partially by activating lung fibroblasts. However, how macrophages communicate with lung fibroblasts is largely unexplored. Exosomes can mediate intercellular communication, whereas its role in lung fibrogenesis is unclear. Here we aim to investigate whether exosomes can mediate the crosstalk between macrophages and lung fibroblasts and subsequently induce fibrosis. METHODS: In vivo, bleomycin (BLM)-induced lung fibrosis model was established and macrophages infiltration was examined. The effects of GW4869, an exosomes inhibitor, on lung fibrosis were assessed. Moreover, macrophage exosomes were injected into mice to observe its pro-fibrotic effects. In vitro, exosomes derived from angiotensin II (Ang II)-stimulated macrophages were collected. Then, lung fibroblasts were treated with the exosomes. Twenty-four hours later, protein levels of α-collagen I, angiotensin II type 1 receptor (AT1R), transforming growth factor-β (TGF-β), and phospho-Smad2/3 (p-Smad2/3) in lung fibroblasts were examined. The Student's t test or analysis of variance were used for statistical analysis. RESULTS: In vivo, BLM-treated mice showed enhanced infiltration of macrophages, increased fibrotic alterations, and higher levels of Ang II and AT1R. GW4869 attenuated BLM-induced pulmonary fibrosis. Mice with exosomes injection showed fibrotic features with higher levels of Ang II and AT1R, which was reversed by irbesartan. In vitro, we found that macrophages secreted a great number of exosomes. The exosomes were taken by fibroblasts and resulted in higher levels of AT1R (0.22 ± 0.02 vs. 0.07 ± 0.02, t = 8.66, P = 0.001), TGF-β (0.54 ± 0.05 vs. 0.09 ± 0.06, t = 10.00, P < 0.001), p-Smad2/3 (0.58 ± 0.06 vs. 0.07 ± 0.03, t = 12.86, P < 0.001) and α-collagen I (0.27 ± 0.02 vs. 0.16 ± 0.01, t = 7.01, P = 0.002), and increased Ang II secretion (62.27 ± 7.32 vs. 9.56 ± 1.68, t = 12.16, P < 0.001). Interestingly, Ang II increased the number of macrophage exosomes, and the protein levels of Alix (1.45 ± 0.15 vs. 1.00 ± 0.10, t = 4.32, P = 0.012), AT1R (4.05 ± 0.64 vs. 1.00 ± 0.09, t = 8.17, P = 0.001), and glyceraldehyde-3-phosphate dehydrogenase (2.13 ± 0.36 vs. 1.00 ± 0.10, t = 5.28, P = 0.006) were increased in exosomes secreted by the same number of macrophages, indicating a positive loop between Ang II and exosomes production. CONCLUSIONS Exosomes mediate intercellular communication between macrophages and fibroblasts plays an important role in BLM-induced pulmonary fibrosis.
Angiotensin II ; Animals ; Bleomycin/toxicity* ; Exosomes ; Fibroblasts ; Lung ; Macrophages ; Mice ; Mice, Inbred C57BL ; Pulmonary Fibrosis/chemically induced* ; Receptor, Angiotensin, Type 1

Angiotensin II Type 1 Receptor Blockers/adverse effects* ; Angiotensin-Converting Enzyme 2 ; Angiotensin-Converting Enzyme Inhibitors/adverse effects* ; Betacoronavirus ; COVID-19 ; Coronavirus Infections/etiology* ; Humans ; Pandemics ; Peptidyl-Dipeptidase A/physiology* ; Pneumonia, Viral/etiology* ; SARS-CoV-2

With the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) all over the world, there is an increasing number of children with such infection. Angiotensin-converting enzyme 2 (ACE2), one of the binding sites for SARS-CoV-2 infection in humans, can bind to viral spike proteins, allowing transmembrane serine protease (TMPRSS2) to activate S-protein to trigger infection and induce the production of various inflammatory factors such as interleukin-1, interferon-l, and tumor necrosis factor. Compared with adults, children tend to have lower expression levels of ACE2 and TMPRSS2, which are presumed to be associated with milder symptoms and fewer cases in children. The article summarizes the research advances in the role of ACE2 during SARS-CoV-2 infection, in order to help understand the pathogenic mechanism of SARS-CoV-2 and provide a reference for better development of drugs and vaccines to prevent and treat coronavirus disease 2019 in children.
Angiotensin-Converting Enzyme 2/metabolism* ; COVID-19 ; Child ; Humans ; Receptors, Virus/metabolism* ; SARS-CoV-2 ; Serine Endopeptidases/metabolism*

BACKGROUND: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice.METHODS: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase α (G6Pase-α), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ζ (PKCζ) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice.RESULTS: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a 40 μM concentration without a change in G6Pase-α expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 (p-IRS-1-Ser302) and decreased p-IRS-1-Tyr632 dose-dependently. Telmisartan dose-dependently increased p-PKCζ-Thr410 which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative PKCζ significantly attenuated telmisartan-induced HGP and p-IRS-1-Ser302 and -inhibited p-IRS-1-Tyr632. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor γ (PPARγ) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased p-IRS-1-Ser302 and decreased p-IRS-1-Tyr632, which was accompanied by an increase in p-PKCζ-Thr410.CONCLUSION: These results suggest that telmisartan increases HGP by inducing p-PKCζ-Thr410 that increases p-IRS-1-Ser302 and decreases p-IRS-1-Tyr632 in a PPARγ-independent manner.
Animals ; Blotting, Western ; Diabetes Mellitus, Type 2 ; Diet, High-Fat ; Ectopic Gene Expression ; Glucose ; Glucose-6-Phosphatase ; Hep G2 Cells ; Insulin Receptor Substrate Proteins ; Insulin ; Liver ; Losartan ; Mice ; Peroxisomes ; Phosphoenolpyruvate ; Phosphorylation ; Protein Kinase C ; Protein Kinases ; Receptor, Angiotensin, Type 1 ; Receptor, Insulin ; Serine

BACKGROUND AND OBJECTIVES: Angiotensin II (Ang II) has been suggested to accelerate vascular senescence, however the molecular mechanism(s) remain unknown. METHODS: We cultured human coronary artery smooth muscle cells (hCSMCs) and treated Ang II and/or fimasartan. Or we transfected adenoviral vectors expressing CYR61 (Ad-CYR61) or antisense CYR61 (Ad-As-CYR61). Cellular senescence was evaluated senescence-associated β-galactosidase (SA-β-gal) assay. The molecular mechanisms were investigated real-time PCR and western blots. RESULTS: SA-β-gal-positive cells significantly increased in Ang II-treated hCSMCs (5.77±1.43-fold compared with the control). The effect of Ang II was significantly attenuated by pretreatment with the Ang II type 1 receptor blocker, fimasartan (2.00±0.92-fold). The expression of both p53 and p16 senescence regulators was significantly increased by Ang II (p53: 1.39±0.17, p16: 1.19±0.10-fold vs. the control), and inhibited by fimasartan. Cysteine-rich angiogenic protein 61 (CYR61) was rapidly induced by Ang II. Compared with the control, Ad-CYR61-transfected hCSMCs showed significantly increased SA-β-gal-positive cells (3.47±0.65-fold). Upon transfecting Ad-AS-CYR61, Ang II-induced senescence (3.74±0.23-fold) was significantly decreased (1.77±0.60-fold). p53 expression by Ang II was significantly attenuated by Ad-AS-CYR61, whereas p16 expression was not regulated. Ang II activated ERK1/2 and p38 MAPK, which was significantly blocked by fimasartan. ERK and p38 inhibition both regulated Ang II-induced CYR61 expression. However, p53 expression was only regulated by ERK1/2, whereas p16 expression was only attenuated by p38 MAPK. CONCLUSIONS: Ang II induced vascular senescence by the ERK/p38 MAPK–CYR61 pathway and ARB, fimasartan, protected against Ang II-induced vascular senescence.
Aging ; Angiotensin II Type 1 Receptor Blockers ; Angiotensin II ; Angiotensins ; Blotting, Western ; Cell Aging ; Coronary Vessels ; Humans ; Muscle, Smooth, Vascular ; Myocytes, Smooth Muscle ; p38 Mitogen-Activated Protein Kinases ; Real-Time Polymerase Chain Reaction ; Receptor, Angiotensin, Type 1

OBJECTIVE: To explore the effect of telmisartan on the expression of metadherin in the kidney of mice with unilateral ureter obstruction. METHODS: Eighteen male C57 mice were randomized into sham-operated group, model group and telmisartan treatment group. In the latter two groups, renal interstitial fibrosis as the result of unilateral ureter obstruction (UUO) was induced by unilateral ureteral ligation with or without telmisartan intervention. Renal pathological changes of the mice were assessed using Masson staining, and immunohistochemistry and Western blotting were used to detect the expression of extracellular matrix proteins and metadherin in the kidney of the mice. In the experiment, cultured mouse renal tubular epithelial cells (mTECs) were stimulated with transforming growth factor-β1 (TGF-β1) and transfected with a siRNA targeting metadherin, and the changes in the expressions of extracellular matrix proteins and metadherin were detected using Western blotting. RESULTS: The expressions of extracellular matrix proteins and metadherin increased significantly in the kidney of mice with UUO ( < 0.05). Intervention with telmisartan significantly lowered the expressions of extracellular matrix proteins and metadherin and alleviated the pathology of renal fibrosis in mice with UUO ( < 0.05). In cultured mTECs, siRNA-mediated knockdown of metadherin obviously reversed TGF-β1-induced increase in the expressions of extracellular matrix proteins and metadherin. CONCLUSIONS Telmisartan can suppress the production of extracellular matrix proteins and the expression of metadhein to attenuate UUO-induced renal fibrosis in mice.
Angiotensin II Type 1 Receptor Blockers ; Animals ; Antihypertensive Agents ; Extracellular Matrix Proteins ; metabolism ; Fibrosis ; Kidney ; drug effects ; metabolism ; pathology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred C57BL ; RNA, Small Interfering ; Random Allocation ; Telmisartan ; pharmacology ; Transforming Growth Factor beta1 ; pharmacology ; Ureteral Obstruction ; complications ; metabolism

BACKGROUND/AIMS: Olmesartan, a widely used angiotensin II receptor blocker (ARB), has been linked to sprue-like enteropathy. No cases of olmesartan-associated enteropathy have been reported in Northeast Asia. We investigated the associations between olmesartan and other ARBs and the incidence of enteropathy in Korea. METHODS: Our retrospective cohort study used data from the Korean National Health Insurance Service to identify 108,559 patients (58,186 females) who were initiated on angiotensin converting enzyme inhibitors (ACEis), olmesartan, or other ARBs between January 2005 and December 2012. The incidences of enteropathy were compared among drug groups. Changes in body weight were compared after propensity score matching of patients in the ACEis and olmesartan groups. RESULTS: Among 108,559 patients, 31 patients were diagnosed with enteropathy. The incidences were 0.73, 0.24, and 0.37 per 1,000 persons, in the ACEis, olmesartan, and other ARBs groups, respectively. Adjusted rate ratios for enteropathy were: olmesartan, 0.33 (95% confidential interval [CI], 0.10 to 1.09; p = 0.070) and other ARBs, 0.34 (95% CI, 0.14 to 0.83; p = 0.017) compared to the ACEis group after adjustment for age, sex, income level, and various comorbidities. The post hoc analysis with matched cohorts revealed that the proportion of patients with significant weight loss did not differ between the ACEis and olmesartan groups. CONCLUSIONS: Olmesartan was not associated with intestinal malabsorption or significant body weight loss in the general Korean population. Additional large-scale prospective studies of the relationship between olmesartan and the incidence of enteropathy in the Asian population are needed.
Angiotensin Receptor Antagonists ; Angiotensin-Converting Enzyme Inhibitors ; Asia ; Asian Continental Ancestry Group ; Body Weight ; Cohort Studies* ; Comorbidity ; Drug-Related Side Effects and Adverse Reactions ; Humans ; Incidence ; Insurance Claim Review ; Intestinal Diseases ; Korea ; National Health Programs ; Propensity Score ; Prospective Studies ; Receptors, Angiotensin ; Retrospective Studies ; Weight Loss

Angiotensin II type 1 receptor (AT1R) antibodies directly injure endothelial and vascular smooth muscle cells by activating transcription factors associated with proinflammatory responses. Previous studies have shown that AT1R antibodies are associated with allograft rejection and decreased graft survival in kidney transplantation. Development of enzyme-linked immunosorbent assay has facilitated semiquantitative detection of AT1R antibodies. Assessing AT1R antibodies along with donor specific human leukocyte antigen antibodies may have potential to identify patients with possible risk for allograft injury and improve overall outcomes. In this review, we summarize recent clinical studies about AT1R antibodies in kidney transplantation and provide perspectives for future research area.
Activating Transcription Factors ; Allografts ; Angiotensin II ; Angiotensins ; Antibodies ; Enzyme-Linked Immunosorbent Assay ; Graft Survival ; Humans ; Kidney Transplantation ; Kidney ; Leukocytes ; Muscle, Smooth, Vascular ; Receptor, Angiotensin, Type 1 ; Tissue Donors ; Transplantation

PURPOSE: Statins, metformin, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin receptor blockers (ARBs) have been suggested for treating age-related macular degeneration (AMD) due to their pleiotropic effects. Therefore, we investigated whether these drugs prevent AMD. MATERIALS AND METHODS: We conducted a nested case-control study using the Korean National Health Insurance Service database. Using risk-set sampling of age, sex, cohort entry date, and follow-up duration, we identified incident patients with AMD and 10 matching controls in cohorts with diabetes mellitus or cardiovascular diseases. Exposure was assessed within one year before the index date using patient prescription records. We conducted conditional logistic regression to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the association between cardiovascular medications and AMD. RESULTS: Our study included 2330 cases and 23278 controls from a cohort of 231274 patients. The ORs (95% CI) for AMD occurrence in users prescribed with statins, metformin, ACE inhibitors, and ARBs were 1.12 (0.94–1.32), 1.15 (0.91–1.45), 0.90 (0.61–1.34), and 1.21 (1.05–1.39), respectively. A duration-response was not observed. CONCLUSION: Statins, metformin, ACE inhibitors, and ARBs did not inhibit AMD in elderly patients. The absence of a duration-response supports the lack of a causal relationship.
Aged ; Angiotensin II ; Angiotensin Receptor Antagonists ; Angiotensin-Converting Enzyme Inhibitors ; Angiotensins ; Cardiovascular Diseases ; Case-Control Studies ; Cohort Studies ; Diabetes Mellitus ; Follow-Up Studies ; Humans ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; Logistic Models ; Macular Degeneration ; Metformin ; National Health Programs ; Odds Ratio ; Prescriptions ; Receptors, Angiotensin