Extracellular vesicles(EVs)are membranous vesicular structures released from almost all eukaryotic cell types under different physiological or pathological conditions.Growing evidence demonstrates that EVs can serve a...Extracellular vesicles(EVs)are membranous vesicular structures released from almost all eukaryotic cell types under different physiological or pathological conditions.Growing evidence demonstrates that EVs can serve as mediators of intercellular communication between donor and recipient cells or microorganism-infected and noninfected cells.Coronavirus disease 2019(COVID-19)disease is caused by infection of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)of host cells in the respiratory system and various extra-pulmonary tissue/organs,resulting in complications of multiple organ systems.As the cell surface receptor,angiotensin-converting enzyme 2(ACE2)mediates cellular entry of SARS-CoV-2 into the host cells in patients with COVID-19.Recent studies have found that ACE2 can be released with EVs,which have been shown to interfere with the entry of the virus into host cells and thus may be involved in COVID-19 pathophysiology.In addition,ACE2,neprilysin(NEP),and thimet oligopeptidase(TOP)are the key enzymes that regulate angiotensin metabolism by converting angiotensin II or angiotensin I to angiotensin 1-7,the latter of which has protective effects in counterbalancing the harmful effects of angiotensin II in COVID-19 disease.This review summarizes the recent research progress regarding EV-associated ACE2,NEP,and TOP and the perspectives of their potential involvement in the pathophysiology of COVID-19 disease.展开更多
The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can ...The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.展开更多
Summary: In order to investigate whether Yinchenhao decoction (YCHD) attenuates hepatic fibro- genesis in the bile duct ligation (BDL) model via recovering and restoring the self-regulation and bal- ance of the r...Summary: In order to investigate whether Yinchenhao decoction (YCHD) attenuates hepatic fibro- genesis in the bile duct ligation (BDL) model via recovering and restoring the self-regulation and bal- ance of the renin-angiotensin system (RAS), 33 specific-pathogen-free (SPF) male Sprague-Dawley rats with common BDL and scission were randomly divided into five groups as follows: G1, the sham group (n=4); G2, BDL 7-day group (n=5); G3, BDL+YCHD 430 mg/mL (n=8); G4, BDL+losartan 0.65 mg/mL (ARB group, n=8); G5, model group (BDL without any treatment, n=8). YCHD and losartan (10 mL.kgl.day-1) were given by gastric gavage for 16 days following BDL in G3 and G4 groups, respec- tively. The effect of YCHD on liver fibrosis and the detailed molecular mechanisms were assessed by liver function including total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IDBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Histological changes were ob-. served by transmission electron microscopy (TEM) and Masson trichrome staining. Western blotting was used to detect the protein expression level of the renin-angiotensin system (RAS) components in- cluding angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1R), ACE2, angio- tensin II (Ang II) as well as transforming growth factor 131 (TGF131). The experimental data were ana- lyzed by principle component analytical method of pattern recognition. The results showed that bio- chemically, serum TBIL, DBIL, IDBIL, ALT and AST levels were markedly increased following BDL as compared with the sham group (P〈0.05). Serum TBIL, IDBIL and DBIL levels in G3 group were dramatically decreased as compared with G5 and G4 groups (P〈0.05). Serum AST level in G3 was sig- nificantly lowered than in G5 group (P〈0.05), but there was no significant difference in ALT among G3, G4 and G5 groups (P〉0.05). Histologically, livers in G3 group showed less hepatocytes necrosis, less bile duct hyperplasia and less collagen formation than in G4 and G5 groups. The protein expression lev- els of ACE2, ACE, Ang II, AT1R and TGF131 in G2, G3 and G4 groups were significantly higher than in sham group (P〈0.05), and lower than in G5 group (P〈0.05). However, the differences among G2, G3 and G4 groups were not significant (P〉0.05). ACE2 protein expression in G3 group was significantly higher than in G2 group (P〈0.05) and there was no significant difference in comparison with G4 group (P〉0.05). Moreover, the protein expression of TGF131 in G3 group was significantly lower than in G5 and G4 groups (P〈0.05). Our findings suggest that the antifibrotic effects of YCHD may be associated with the decreased classical RAS pathway components and TGFI31 downexpression so as to recover and rebuild self-regulation of the RAS by elevating the protein expression of ACE2.展开更多
The emergence of coronavirus disease-2019 induced by a newly identified bcoronavirus, namely severe acute respiratory syndrome coronavirus 2(SARSCoV-2) has constituted a public health emergency. Even though it was con...The emergence of coronavirus disease-2019 induced by a newly identified bcoronavirus, namely severe acute respiratory syndrome coronavirus 2(SARSCoV-2) has constituted a public health emergency. Even though it was considered a zoonotic disease, the virus has also spread among humans via respiratory secretions. The expression and distribution of angiotensin converting enzyme type 2(ACE2) in various human organs might also show other possible infection routes. High ACE2 ribonucleic acid expression has been identified in the gastrointestinal tract(GI) indicating its importance as a possible infection pathway of SARS-CoV-2. ACE2 induces viral entry into the host and most importantly has been found to be associated with the function of the gut. Its deficiency has been implicated in several pathologies such as colorectal inflammation. The renin-angiotensin system(RAS) is an essential regulatory cascade operating both at a local tissue level and at the systemic or circulatory level. The RAS may be important in the pathogenesis of chronic liver disease and is associated with the up-regulation of ACE2. Thus, the aim of this review is firstly, the analysis of some important general and genome characteristics of SARS-CoV-2 and secondly, and most importantly, to focus on the utility of ACE2 receptors in both SARS-CoV-2 replication and pathogenesis, especially in the GI tract.展开更多
The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the virus responsible for coronavirus disease 2019(COVID-19),enters affected cells through the angiotensin-converting enzyme 2(ACE2)receptor,which is hig...The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the virus responsible for coronavirus disease 2019(COVID-19),enters affected cells through the angiotensin-converting enzyme 2(ACE2)receptor,which is highly expressed in type II alveolar cells,enterocytes,and cholangiocytes.SARS-CoV-2 infection causes fever,dry cough,and breathing difficulty,which can progress to respiratory distress due to interstitial pneumonia,and hepatobiliary injury due to COVID-19 is increasingly recognized.The hepatobiliary injury may be evident at presentation of the disease or develop during the disease progression.The development of more severe clinical outcomes in patients with chronic liver diseases(CLD)with or without cirrhosis infected with SARS-CoV-2 has not been elucidated.Moreover,there is limited data related to common medications that affect the disease severity of COVID-19 patients.Additionally,ACE2 receptor expression of hepatobiliary tissue related to the disease severity also have not been clarified.This review summarized the current situation regarding the clinical outcomes of COVID-19 patients with chronic liver diseases who were treated with common medications.Furthermore,the association between ACE2 receptor expression and disease severity in these patients is discussed.展开更多
Background: Breast cancer is the most common type of cancer among women. Diagnosed and treated timely, patients may have good prognostics. In Brazil, in 2012, the estimate of new cases was 52,680 and the number of reg...Background: Breast cancer is the most common type of cancer among women. Diagnosed and treated timely, patients may have good prognostics. In Brazil, in 2012, the estimate of new cases was 52,680 and the number of registered deaths in 2012 was 12,852. The Renin-Angiotensin System (RAS) is known for its role in arterial hypertension and in other cardiovascular diseases. Angiotensin-Converting Enzyme 2 (ACE2) is the key to Ang-(1-7) formation, and counterbalances the ACE1/AngII/AGTR1 axis actions. RAS components have complex interactions with different tissues and their actions are not restricted to the cardiovascular system. Recently, the RAS has been associated with different types of cancers and in particular with gynecological cancers. Objectives: Our aim is to investigate possible associations between allelic distribution of two genetic polymorphisms in the AGTR2 receptor with ACEs 1 and 2 plasma levels among women with breast cancer. Patients and Methods: Patients with breast cancer were genotyped for two polymorphisms of the AGTR2 (T1247G and A5235G). Genotyping assays (TaqMan) were performed with genomic DNA extracted from blood cells. ACEs plasma level measurements were conducted in women from the breast-cancer group (N = 53). ACEs were measured in the plasma of these patients using ELISA kits. Results: SNPs genotype distribution is correlated with ACEs plasma levels. ACEs plasma levels are also correlated with clinical variables and ACE2 high levels are associated with better prognostics. Conclusions: Changes in circulating levels of ECA1/AngII ECA2/ Ang-(1-7) determine the magnitude of the inflammatory response that an individual can trigger and the variation in ACE 1 and 2 plasma level measurements in the blood of breast cancer patients suggests an association with the process of mammary carcinogenesis. Thus, the RAS may be associated with the process of mammary carcinogenesis by both genotypic variations of RAS components and by circulating levels of ACEs.展开更多
The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has triggered a widespread outbreak since December 2019.The SARS-CoV-2 infection-related illness has been dubbed the coronavirus disease 2019(COVID-19)by ...The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has triggered a widespread outbreak since December 2019.The SARS-CoV-2 infection-related illness has been dubbed the coronavirus disease 2019(COVID-19)by the World Health Organization.Asymptomatic and subclinical infections,a severe hyperinflammatory state,and mortality are all examples of clinical signs.After attaching to the angiotensin converting enzyme 2(ACE2)receptor,the SARSCoV-2 virus can enter cells through membrane fusion and endocytosis.In addition to enabling viruses to cling to target cells,the connection between the spike protein(S-protein)of SARS-CoV-2 and ACE2 may potentially impair the functionality of ACE2.Blood pressure is controlled by ACE2,which catalyzes the hydrolysis of the active vasoconstrictor octapeptide angiotensin(Ang)II to the heptapeptide Ang-(1-7)and free L-Phe.Additionally,Ang I can be broken down by ACE2 into Ang-(1-9)and metabolized into Ang-(1-7).Numerous studies have demonstrated that circulating ACE2(cACE2)and Ang-(1-7)have the ability to restore myocardial damage in a variety of cardiovascular diseases and have antiinflammatory,antioxidant,anti-apoptotic,and anti-cardiomyocyte fibrosis actions.There have been some suggestions for raising ACE2 expression in COVID-19 patients,which might be used as a target for the creation of novel treatment therapies.With regard to this,SARS-CoV-2 is neutralized by soluble recombinant human ACE2(hrsACE2),which binds the viral S-protein and reduces damage to a variety of organs,including the heart,kidneys,and lungs,by lowering Ang II concentrations and enhancing conversion to Ang-(1-7).This review aims to investigate how the presence of SARS-CoV-2 and cACE2 are related.Additionally,there will be discussion of a number of potential therapeutic approaches to tip the ACE/ACE-2 balance in favor of the ACE-2/Ang-(1-7)axis.展开更多
Objectives To examine in vivo interactions between angiotensin Ⅱ (Ang Ⅱ ) AT1 a receptor (AT1 aR), angiotensin-converting enzymes (ACE) and ACE2 using small hairpin RNA (shRNA) gene-silencing methods in mice...Objectives To examine in vivo interactions between angiotensin Ⅱ (Ang Ⅱ ) AT1 a receptor (AT1 aR), angiotensin-converting enzymes (ACE) and ACE2 using small hairpin RNA (shRNA) gene-silencing methods in mice brainstem nucleus tractus solitarius (NTS). Methods C57BL mice (n = 8 ) were used as animal model. Method of micro-injection in the nucleus of NTS was adopted. After ten days, mice were killed and their brain tissue were fixed and sectioned. The expression levels of AT1 aR, ACE and ACE2 mRNA at both sides of NTS were examined by in situ hybridization. Based on compared t-test, the changing for mRNA expression was examined. Results After the expression of ATlaR mRNA was significantly inhibited (61.6% ± 6.8% ) by ATlaR-shRNA, it was associated with decreases in ACE2 mRNA expression from ( 1.05 ± 0. 12) μCi/mg to (0. 74 ± 0.09 ) μCi/mg ( 29.0% ± 14. 5% , P 〈 0. 01 ) on the same side of the brainstem. ACE mRNA expression was consistent at both sides ( 0. 50 μCi/mg ± 0. 09μCi/mg and 0. 53 μCi/mg ± 0. 08 μCi/mg), with insignificant difference ( P 〉 0. 05 ). Conclusions The gene silencing result showed that there were interactions between brainstem AT1 aR and ACE2. ACE mRNA expression was not altered by RNA interference treatment at AT1 aR.展开更多
文摘Extracellular vesicles(EVs)are membranous vesicular structures released from almost all eukaryotic cell types under different physiological or pathological conditions.Growing evidence demonstrates that EVs can serve as mediators of intercellular communication between donor and recipient cells or microorganism-infected and noninfected cells.Coronavirus disease 2019(COVID-19)disease is caused by infection of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)of host cells in the respiratory system and various extra-pulmonary tissue/organs,resulting in complications of multiple organ systems.As the cell surface receptor,angiotensin-converting enzyme 2(ACE2)mediates cellular entry of SARS-CoV-2 into the host cells in patients with COVID-19.Recent studies have found that ACE2 can be released with EVs,which have been shown to interfere with the entry of the virus into host cells and thus may be involved in COVID-19 pathophysiology.In addition,ACE2,neprilysin(NEP),and thimet oligopeptidase(TOP)are the key enzymes that regulate angiotensin metabolism by converting angiotensin II or angiotensin I to angiotensin 1-7,the latter of which has protective effects in counterbalancing the harmful effects of angiotensin II in COVID-19 disease.This review summarizes the recent research progress regarding EV-associated ACE2,NEP,and TOP and the perspectives of their potential involvement in the pathophysiology of COVID-19 disease.
文摘The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.
基金supported by grants from the National Natural Science Foundation of China(No.81102692)the Natural Science Foundation of Hubei Province,China(No.JX6B09)the Fundamental Research Funds for the Central Universities,China(No.2015QN203)
文摘Summary: In order to investigate whether Yinchenhao decoction (YCHD) attenuates hepatic fibro- genesis in the bile duct ligation (BDL) model via recovering and restoring the self-regulation and bal- ance of the renin-angiotensin system (RAS), 33 specific-pathogen-free (SPF) male Sprague-Dawley rats with common BDL and scission were randomly divided into five groups as follows: G1, the sham group (n=4); G2, BDL 7-day group (n=5); G3, BDL+YCHD 430 mg/mL (n=8); G4, BDL+losartan 0.65 mg/mL (ARB group, n=8); G5, model group (BDL without any treatment, n=8). YCHD and losartan (10 mL.kgl.day-1) were given by gastric gavage for 16 days following BDL in G3 and G4 groups, respec- tively. The effect of YCHD on liver fibrosis and the detailed molecular mechanisms were assessed by liver function including total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IDBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Histological changes were ob-. served by transmission electron microscopy (TEM) and Masson trichrome staining. Western blotting was used to detect the protein expression level of the renin-angiotensin system (RAS) components in- cluding angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1R), ACE2, angio- tensin II (Ang II) as well as transforming growth factor 131 (TGF131). The experimental data were ana- lyzed by principle component analytical method of pattern recognition. The results showed that bio- chemically, serum TBIL, DBIL, IDBIL, ALT and AST levels were markedly increased following BDL as compared with the sham group (P〈0.05). Serum TBIL, IDBIL and DBIL levels in G3 group were dramatically decreased as compared with G5 and G4 groups (P〈0.05). Serum AST level in G3 was sig- nificantly lowered than in G5 group (P〈0.05), but there was no significant difference in ALT among G3, G4 and G5 groups (P〉0.05). Histologically, livers in G3 group showed less hepatocytes necrosis, less bile duct hyperplasia and less collagen formation than in G4 and G5 groups. The protein expression lev- els of ACE2, ACE, Ang II, AT1R and TGF131 in G2, G3 and G4 groups were significantly higher than in sham group (P〈0.05), and lower than in G5 group (P〈0.05). However, the differences among G2, G3 and G4 groups were not significant (P〉0.05). ACE2 protein expression in G3 group was significantly higher than in G2 group (P〈0.05) and there was no significant difference in comparison with G4 group (P〉0.05). Moreover, the protein expression of TGF131 in G3 group was significantly lower than in G5 and G4 groups (P〈0.05). Our findings suggest that the antifibrotic effects of YCHD may be associated with the decreased classical RAS pathway components and TGFI31 downexpression so as to recover and rebuild self-regulation of the RAS by elevating the protein expression of ACE2.
文摘The emergence of coronavirus disease-2019 induced by a newly identified bcoronavirus, namely severe acute respiratory syndrome coronavirus 2(SARSCoV-2) has constituted a public health emergency. Even though it was considered a zoonotic disease, the virus has also spread among humans via respiratory secretions. The expression and distribution of angiotensin converting enzyme type 2(ACE2) in various human organs might also show other possible infection routes. High ACE2 ribonucleic acid expression has been identified in the gastrointestinal tract(GI) indicating its importance as a possible infection pathway of SARS-CoV-2. ACE2 induces viral entry into the host and most importantly has been found to be associated with the function of the gut. Its deficiency has been implicated in several pathologies such as colorectal inflammation. The renin-angiotensin system(RAS) is an essential regulatory cascade operating both at a local tissue level and at the systemic or circulatory level. The RAS may be important in the pathogenesis of chronic liver disease and is associated with the up-regulation of ACE2. Thus, the aim of this review is firstly, the analysis of some important general and genome characteristics of SARS-CoV-2 and secondly, and most importantly, to focus on the utility of ACE2 receptors in both SARS-CoV-2 replication and pathogenesis, especially in the GI tract.
文摘The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the virus responsible for coronavirus disease 2019(COVID-19),enters affected cells through the angiotensin-converting enzyme 2(ACE2)receptor,which is highly expressed in type II alveolar cells,enterocytes,and cholangiocytes.SARS-CoV-2 infection causes fever,dry cough,and breathing difficulty,which can progress to respiratory distress due to interstitial pneumonia,and hepatobiliary injury due to COVID-19 is increasingly recognized.The hepatobiliary injury may be evident at presentation of the disease or develop during the disease progression.The development of more severe clinical outcomes in patients with chronic liver diseases(CLD)with or without cirrhosis infected with SARS-CoV-2 has not been elucidated.Moreover,there is limited data related to common medications that affect the disease severity of COVID-19 patients.Additionally,ACE2 receptor expression of hepatobiliary tissue related to the disease severity also have not been clarified.This review summarized the current situation regarding the clinical outcomes of COVID-19 patients with chronic liver diseases who were treated with common medications.Furthermore,the association between ACE2 receptor expression and disease severity in these patients is discussed.
文摘Background: Breast cancer is the most common type of cancer among women. Diagnosed and treated timely, patients may have good prognostics. In Brazil, in 2012, the estimate of new cases was 52,680 and the number of registered deaths in 2012 was 12,852. The Renin-Angiotensin System (RAS) is known for its role in arterial hypertension and in other cardiovascular diseases. Angiotensin-Converting Enzyme 2 (ACE2) is the key to Ang-(1-7) formation, and counterbalances the ACE1/AngII/AGTR1 axis actions. RAS components have complex interactions with different tissues and their actions are not restricted to the cardiovascular system. Recently, the RAS has been associated with different types of cancers and in particular with gynecological cancers. Objectives: Our aim is to investigate possible associations between allelic distribution of two genetic polymorphisms in the AGTR2 receptor with ACEs 1 and 2 plasma levels among women with breast cancer. Patients and Methods: Patients with breast cancer were genotyped for two polymorphisms of the AGTR2 (T1247G and A5235G). Genotyping assays (TaqMan) were performed with genomic DNA extracted from blood cells. ACEs plasma level measurements were conducted in women from the breast-cancer group (N = 53). ACEs were measured in the plasma of these patients using ELISA kits. Results: SNPs genotype distribution is correlated with ACEs plasma levels. ACEs plasma levels are also correlated with clinical variables and ACE2 high levels are associated with better prognostics. Conclusions: Changes in circulating levels of ECA1/AngII ECA2/ Ang-(1-7) determine the magnitude of the inflammatory response that an individual can trigger and the variation in ACE 1 and 2 plasma level measurements in the blood of breast cancer patients suggests an association with the process of mammary carcinogenesis. Thus, the RAS may be associated with the process of mammary carcinogenesis by both genotypic variations of RAS components and by circulating levels of ACEs.
文摘The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has triggered a widespread outbreak since December 2019.The SARS-CoV-2 infection-related illness has been dubbed the coronavirus disease 2019(COVID-19)by the World Health Organization.Asymptomatic and subclinical infections,a severe hyperinflammatory state,and mortality are all examples of clinical signs.After attaching to the angiotensin converting enzyme 2(ACE2)receptor,the SARSCoV-2 virus can enter cells through membrane fusion and endocytosis.In addition to enabling viruses to cling to target cells,the connection between the spike protein(S-protein)of SARS-CoV-2 and ACE2 may potentially impair the functionality of ACE2.Blood pressure is controlled by ACE2,which catalyzes the hydrolysis of the active vasoconstrictor octapeptide angiotensin(Ang)II to the heptapeptide Ang-(1-7)and free L-Phe.Additionally,Ang I can be broken down by ACE2 into Ang-(1-9)and metabolized into Ang-(1-7).Numerous studies have demonstrated that circulating ACE2(cACE2)and Ang-(1-7)have the ability to restore myocardial damage in a variety of cardiovascular diseases and have antiinflammatory,antioxidant,anti-apoptotic,and anti-cardiomyocyte fibrosis actions.There have been some suggestions for raising ACE2 expression in COVID-19 patients,which might be used as a target for the creation of novel treatment therapies.With regard to this,SARS-CoV-2 is neutralized by soluble recombinant human ACE2(hrsACE2),which binds the viral S-protein and reduces damage to a variety of organs,including the heart,kidneys,and lungs,by lowering Ang II concentrations and enhancing conversion to Ang-(1-7).This review aims to investigate how the presence of SARS-CoV-2 and cACE2 are related.Additionally,there will be discussion of a number of potential therapeutic approaches to tip the ACE/ACE-2 balance in favor of the ACE-2/Ang-(1-7)axis.
文摘Objectives To examine in vivo interactions between angiotensin Ⅱ (Ang Ⅱ ) AT1 a receptor (AT1 aR), angiotensin-converting enzymes (ACE) and ACE2 using small hairpin RNA (shRNA) gene-silencing methods in mice brainstem nucleus tractus solitarius (NTS). Methods C57BL mice (n = 8 ) were used as animal model. Method of micro-injection in the nucleus of NTS was adopted. After ten days, mice were killed and their brain tissue were fixed and sectioned. The expression levels of AT1 aR, ACE and ACE2 mRNA at both sides of NTS were examined by in situ hybridization. Based on compared t-test, the changing for mRNA expression was examined. Results After the expression of ATlaR mRNA was significantly inhibited (61.6% ± 6.8% ) by ATlaR-shRNA, it was associated with decreases in ACE2 mRNA expression from ( 1.05 ± 0. 12) μCi/mg to (0. 74 ± 0.09 ) μCi/mg ( 29.0% ± 14. 5% , P 〈 0. 01 ) on the same side of the brainstem. ACE mRNA expression was consistent at both sides ( 0. 50 μCi/mg ± 0. 09μCi/mg and 0. 53 μCi/mg ± 0. 08 μCi/mg), with insignificant difference ( P 〉 0. 05 ). Conclusions The gene silencing result showed that there were interactions between brainstem AT1 aR and ACE2. ACE mRNA expression was not altered by RNA interference treatment at AT1 aR.