Angiotensin-(1–7) decreases the expression of collagen I via TGF-β1/Smad2/3 and subsequently inhibits fibroblast–myofibroblast transition

CAV1 Protein Encapsulated in Mouse BMSC-Derived Extracellular Vesicles Alleviates Myocardial Fibrosis Following Myocardial Infarction by Blocking the TGF-β1/SMAD2/c-JUN Axis

Extracellular vesicles (EVs) derived from mouse bone marrow mesenchymal stem cells (mBMSCs) convey the CAV1 protein, influencing the TGF-β1/SMAD2/c-JUN pathway and thus the molecular mechanisms underlying myocardial fibrosis (MF) post-myocardial infarction (MI). Through various experimental methods, including transmission electron microscopy, Nanosight analysis, Western blot, ELISA, and qRT-PCR, we isolated, purified, and identified EVs originating from mBMSCs. Bioinformatics and experimental findings show a reduced expression of CAV1 in myocardial fibrosis tissue. Furthermore, our findings suggest that mBMSC-EVs can deliver CAV1 to cardiac fibroblasts (CFs) and that silencing CAV1 in mBMSC-EVs promotes CF fibrosis. In vivo studies further corroborated these findings. In conclusion, mBMSC-EVs mitigate myocardial fibrosis in MI mice by delivering the CAV1 protein, inhibiting the TGF-β1/SMAD2/c-JUN pathway.

Angiotensin (1-7) Inhibits Transforming Growth Factor-Β1-Induced Epithelial-Mesenchymal Transition of Human Keratinocyte Hacat Cells in vitro

Introduction

Angiotensin (1-7) (Ang-(1-7)) is an emerging component of the renin-angiotensin system (RAS) with effective anti-fibrosis properties and has been shown to interfere with epithelial-mesenchymal transition (EMT) by numerous studies. In recent years, EMT has been proposed as a new therapeutic target for skin fibrotic diseases such as keloids. However, the effect of Ang-(1-7) on EMT in skin is still unclear. Hence, the purpose of this study was to explore the effect of Ang-(1-7) on Transforming growth factor-β1(TGF-β1)-induced EMT of human immortalized keratinocytes HaCaT in vitro.

Methods

The study involved the use of the human immortalized keratinocyte cell line (HaCaT). The cells were cultured in high-glucose DMEM medium with 10% fetal bovine serum and 1% penicillin-streptomycin. Four groups were created for experimentation: control group (Group C), TGF-β1-treated group (Group T), Ang-(1-7)-treated group (Group A), and a group treated with both TGF-β1 and Ang-(1-7) (Group A + T). Various assays were conducted, including a cell proliferation assay using CCK-8 solution, a scratch wound healing assay to evaluate cell migration, and Western blotting to detect protein expressions related to cell characteristics. Additionally, quantitative real-time polymerase chain reaction (PCR) was performed to analyze epithelial-mesenchymal transition (EMT) related gene expression levels. The study aimed to investigate the effects of TGF-β1 and Ang-(1-7) on HaCaT cells.

Results

We found that Ang-(1-7) not only reduced the migration of HaCaT cells induced by TGF-β1 in vitro but also reduced the expression of α-SMA and vimentin, and restored the protein expression of E-cadherin and claudin-1. Mechanistically, Ang-(1-7) inhibits the phosphorylation levels of Smad2 and Smad3 in the TGF-β1 canonical pathway, and suppresses the expression of EMT-related transcription factors (EMT-TFs) such as SNAI2, TWIST1, and ZEB1.

Discussion

Taken together, our findings suggest that Ang-(1-7) inhibits TGF-β1-induced EMT in HaCaT cells in vitro by disrupting the TGF-β1-Smad canonical signaling pathway. These results may be helpful in the treatment of EMT in skin fibrotic diseases such as keloids.

Epithelial cell dysfunction in chronic rhinosinusitis: the epithelial-mesenchymal transition

INTRODUCTION

Epithelial-mesenchymal transition (EMT) is a type of epithelial cell dysfunction, which is widely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS), especially CRS with nasal polyps, and contributes to pathogenesis of the disease. EMT is mediated via complex mechanisms associated with multiple signaling pathways.

AREAS COVERED

We have summarized the underlying mechanisms and signaling pathways promoting EMT in CRS. Strategies or drugs/agents targeting the genes and pathways related to the regulation of EMT are also discussed for their potential use in the treatment of CRS and asthma. A literature search of studies published in English from 2000 to 2023 was conducted using the PubMed database, employing CRS, EMT, signaling, mechanisms, targeting agents/drugs, as individual or combinations of search terms.

EXPERT OPINION

EMT in nasal epithelium not only leads to epithelial cell dysfunction but also plays an important role in nasal tissue remodeling in CRS. A comprehensive understanding of the mechanisms underlying EMT and the development of drugs/agents targeting these mechanisms may provide new treatment strategies for CRS.

Effects of Ziyin Qianyang Formula on Renal Fibrosis through the TGF-β1/Smads Signaling Pathway in Spontaneously Hypertensive Rats

OBJECTIVE

The aim of the study is to explore the effects and mechanisms of action of Ziyin Qianyang Formula (ZYQYF) on renal fibrosis in spontaneously hypertensive rats (SHRs).

METHODS

Forty SHRs were randomly divided into a model group, Ziyin Qianyang Formula regular-dose and high-dose groups (ZYQYF-R, 20 g/kg; ZYQYF-H, 40 g/kg), and a western medicine group (enalapril 10 mg/kg), and 10 Sprague-Dawley rats were selected as the normal group. The rats received continuous gavage administration for 6 weeks and systolic blood pressure (SBP) measurements were obtained every fortnight. The serum levels of urea, serum creatinine (sCr), and uric acid (UA) were measured; the pathological morphology and collagen content of the kidneys were observed by hematoxylin-eosin (HE) and Masson staining; and the serum Ang II level was measured by an enzyme-linked immunosorbent assay (ELISA). Transforming growth factor (TGF)-β1, Smad-2, Smad-3, and Smad-7 protein and mRNA expressions in kidney tissues was evaluated by western blotting and reverse transcription-polymerase chain reaction.

RESULTS

The ZYQYF-H group showed significantly a lower renal weight and renal weight/body weight than the model group. The enalapril and ZYQYF-H groups showed significantly lower SBP than other groups after 6 weeks of administration. The ZYQYF-H group showed better improvement than the ZYQYF-R and enalapril groups in glomerular and tubular morphology and better reductions in inflammatory cell infiltration and collagen volumetric fraction. The ZYQYF-H group also showed better reductions in serum UA and Ang II levels; collagen-I, collagen-III, and p-Smad2/Smad-2 protein expression; and Smad-2 mRNA expression and a better increase in Smad-7 protein and mRNA expression than the enalapril group. Besides, the degree of renal function and fibrosis improvement was positively correlated with the dose of ZYQYF.

CONCLUSION

ZYQYF can significantly reduce SHR blood pressure, protect renal function and structure, and improve renal fibrosis by regulating Smad proteins through TGF-β1.

ASTHMA: ROLE OF THE ANGIOTENSIN-(1-7)/MAS PATHWAY IN PATHOPHYSIOLOGY AND THERAPY

The incidence of asthma is a global health problem, requiring studies aimed at developing new treatments to improve clinical management, thereby reducing personal and economic burdens on the health system. Therefore, the discovery of mediators that promote anti-inflammatory and pro-resolutive events are highly desirable to improve lung function and quality of life in asthmatic patients. In that regard, experimental studies have shown that the Angiotensin-(1-7)/Mas receptor of the renin-angiotensin system (RAS) is a potential candidate for the treatment of asthma. Therefore, we reviewed findings related to the function of the Angiotensin-(1-7)/Mas pathway in regulating the processes associated with inflammation and exacerbations in asthma, including leukocyte influx, fibrogenesis, pulmonary dysfunction and resolution of inflammation. Thus, knowledge of the role of the Angiotensin-(1-7)/Mas can help pave the way for the development of new treatments for this disease with high morbidity and mortality through new experimental and clinical trials.

PPARγ mediates the anti-pulmonary fibrosis effect of icaritin

BACKGROUND

Pulmonary fibrosis is a fatal lung disease with limited treatment options. Icaritin is the active ingredient derived from the traditional Chinese medical plant Epimedium and possesses many biomedical activities. This study aimed to investigate the effects and molecular mechanisms of icaritin on bleomycin-induced pulmonary fibrosis in mice.

METHODS

To assess its preventative effects, bleomycin treated mice received 0, 0.04, 0.2, and 1 mg/kg of icaritin from day 1 onwards. To assess its therapeutic effects, bleomycin treated mice received 0 and 1 mg/kg of icaritin from day 15 onwards. Mice were sacrificed on day 21 and lung tissues were collected, stained with HE, Masson and immunohistochemistry. Q-PCR was used to measure Collagen I and Collagen III expression, western blotting was used to quantify α-SMA, Collagen I expression. Hydroxyproline content was measured using a biochemical method. NIH3T3 and HLF-1 cells were treated with TGF-β1with or without icaritin, and α-SMA, Collagen I were tested. PPARγ antagonist GW9662 and PPARγ-targeted siRNA were used to investigate the mechanism of icaritin in inhibiting myofibroblast differentiation.

RESULTS

Both preventative and therapeutic administration of icaritin improved the histopathological changes, decreased Collagen and α-SMA, lowered hydroxyproline content in bleomycin-treated lung tissues. Icaritin decreased α-SMA and Collagen I expression in TGF-β1-stimulated NIH3T3 and HLF-1 cells. However, its effect in reducing α-SMA and Collagen I expression was suppressed when expression or activity of PPARγ was inhibited.

CONCLUSIONS

Icaritin has therapeutic potential against pulmonary fibrosis via the inhibition of myofibroblast differentiation, which may be mediated by PPARγ.

Impact of angiotensin II type 1 and G-protein-coupled Mas receptor expression on the pulmonary performance of patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a severe interstitial disease with a mean survival of about 2.5-5 years after diagnosis. Its pathophysiology is still a major challenge for science. It is known that angiotensin II (Ang-II) binds AT1 receptor (AT1R) and its overactivation induces fibrosis, inflammation and oxidative stress. In contrast, activation of the Mas receptor (Mas-R) by angiotensin 1-7 opposes the harmful effects induced by Ang-II. Thus, our innovative objective was to analyze, in patients' lung with IPF, the balance between AT1R and Mas-R expression and their possible association with pulmonary spirometric parameters: forced expiratory volume in the first second (FEV1%) and forced vital capacity (FVC%). One cubic centimeter of lung tissue was obtained from IPF patients (n = 6) and from patients without IPF (n = 6) who underwent bronchial carcinoma resection. Receptor expression was quantified using western blot. AT1R expression was significantly higher (34 %) in patients with IPF (P = 0.006), whereas Mas-R was significantly less expressed (54 %) in these patients' lungs (P = 0.046). There was also a positive correlation between Mas-R expression and FEV1% (r = 0.62, P = 0.03) and FVC% (r = 0.58, P = 0.05). Conversely, AT1R expression was negatively correlated with FEV1% (r = 0.80, P = 0.002) and FVC% (r = 0.74, P = 0.006). In conclusion, our results demonstrated an increased expression of AT1R and reduced expression of Mas-R in the lung of patients with IPF. The dominance of AT1R expression is associated with reduced lung function, highlighting the role of the renin-angiotensin system peptides in the pathophysiology of IPF.

Characterization of the Renin-Angiotensin System in Aged Cavernosal Tissue and its Role in Penile Fibrosis

BACKGROUND

The renin-angiotensin system (RAS) plays an important role in erectile function. The RAS contains 2 major axes: one deleterious, composed of ACE-Ang II-AT1 receptor, and another protective, composed of ACE2-Ang-(1-7)-Mas receptor. While aging is a well-known cause for development of male sexual disorders, little is known about local regulation of the RAS in age-related erectile dysfunction (ED).

AIM

The present study aimed to assess regulation of the RAS in aging-associated ED rat model and evaluate possible options for disease management through pharmacological modulation of the RAS.

METHODS

Penile tissues were harvested from 3-, 12-, and 24-month-old Wistar rats. Local expression of major RAS components and ED markers was measured by RT-PCR. Protein expression of RAS components was assessed by western blot. Collagen deposition was measured by Sirius Red and immunohistochemical staining. Evaluation of collagen content was also performed in penile sections of Mas-knockout mice by Sirius Red and Masson's trichrome stainings. Finally, the effect of Ang-(1-7) pretreatment on TGF-β-induced myofibroblast activation was studied in primary cavernosal and immortalized fibroblasts.

OUTCOMES

Experimental results highlighted the essential role of the RAS in modulation of cavernosal fibrosis.

RESULTS

The present study demonstrates local expression of angiotensinogen mRNA alongside with major RAS components, which suggests local autonomous functioning of the RAS within penile tissue. Gene expression analysis revealed strong positive correlation between ACE-Ang II-AT1 axis with markers for inflammation and fibrosis. While corpus cavernosum from 24-month-old rats was characterized by increased collagen deposition, protein expression of ACE, AT1, and Mas was shown to be upregulated in the penile tissue of this group. At the same time, penile sections from Mas-knockout mice (FVB/N background) were also shown to have increased collagen deposition. Finally, it was demonstrated that Ang-(1-7) treatment of primary cavernosal and immortalized fibroblasts was able to alleviate TGF-β-induced fibroblast-to-myofibroblast transition.

CLINICAL TRANSLATION

The present study suggests Ang-(1-7) treatment as a possible strategy for pharmacological management of fibrosis-associated ED in aging.

STRENGTHS & LIMITATIONS

The link between the RAS and penile fibrosis, indicated by a holistic screening of different ED markers, was confirmed by in vivo and in vitro data. However, results, presented in the manuscript, need to be further reinforced by human data. Important to note, the main goal of the study was to characterize RAS regulation in aging condition rather than state any causal relationships.

CONCLUSION

Present study characterizes RAS regulation in aging-associated ED and indicates its important role in cavernosal fibrosis. Bragina ME, Costa-Fraga F, Sturny M, et al. Characterization of the Renin-Angiotensin System in Aged Cavernosal Tissue and its Role in Penile Fibrosis. J Sex Med 2020;17:2129-2140.

Diosgenin inhibits TGF-β1/Smad signaling and regulates epithelial mesenchymal transition in experimental pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a grave disease characterized by abnormal wound healing associated with chronic, progressive, irreversible fatal lung disease, leading to persistent injuries to the alveolar epithelium. A consequent disturbance of fibroblast proliferation and apoptosis results in subsequent release of pro-inflammatory and pro-fibrotic mediators coupled with accumulation of extracellular matrix within the interstitium. Inexorable distortion of lung alveolar architecture leads to respiratory failure with a median survival rate of 3-5 years. Currently available drugs can only slowdown the progression of fibrosis and novel drugs are warranted to treat this disease. In this study, we demonstrate the fibro-protective effect of diosgenin in experimental lung fibrosis through regulation of Epithelial Mesenchymal Transition (EMT). A single dose of 3 U/kg body weight (b.wt) Bleomycin (BLM) was administered intratracheally in Wistar male albino rats and fibrotic animals were treated with diosgenin (100 mg/kg b.wt) orally for 28 days. BLM administered rat show histological alteration with increased mast cell and collagen accumulation. BLM induced abnormalities were significantly reduced upon treatment with diosgenin. Western blot analysis revealed an increased level of pro-inflammatory and pro-fibrotic molecules such as IL-1β and TGF-β in BLM induced rats. Rats supplemented with diosgenin showed a decreased expression of inflammatory and pro-fibrotic mediators. Markers of EMT molecules were evaluated by immunoblot. The results of immunoblot demonstrate that diosgenin regulated the expression of TGF-β mediated EMT. Hence, from the overall study, administration of diosgenin prevents pulmonary fibrosis by restraint inflammation and EMT.

Angiotensin-(1-7) Rescues Chronic Intermittent Hypoxia-Aggravated Transforming Growth Factor-β-Mediated Airway Remodeling in Murine and Cellular Models of Asthma

Renin-angiotensin system (RAS) is involved in TGF-β-mediated epithelial-to-mesenchymal transition (EMT) and is responsible for airway remodeling in refractory asthma. Obstructive sleep apnea (OSA), which affects RAS activity, is a risk factor for refractory asthma. We aimed to investigate how chronic intermittent hypoxia (IH), the main pathophysiology of OSA, exacerbates asthma and whether Ang-(1-7) protects against chronic IH-induced airway remodeling in asthma. We exposed ovalbumin (OVA)-challenged asthma mice to chronic IH and observed that chronic IH aggravated airway inflammation and collagen deposit in OVA-challenged mice. Compared with the OVA group, the OVA + chronic IH group had a lower expression level of epithelial marker E-cadherin and higher expression levels of mesenchymal markers α-smooth muscle actin and collagen IV in airway epithelia, accompanied with activation of TGF-β/Smad pathway. These changes were reversed by the administration of Ang-(1-7). Consistently, Ang-(1-7) mitigated chronic IH-induced activation of TGF-β-mediated EMT in lipopolysaccharide-treated bronchial epithelial cells in a dose-dependent manner, which was blocked by Ang-(1-7)-specific Mas receptor antagonist A779. Taken together, Ang-(1-7) rescued chronic IH-aggravated TGF-β-mediated EMT to suppress airway remodeling, implying that RAS activity is involved in the mechanisms of OSA-related airway dysfunction in asthma. SIGNIFICANCE STATEMENT: OSA is a risk factor for refractory asthma. In this study, we aimed to explore the mechanisms of how OSA exacerbates refractory asthma. We found that chronic IH induces TGF-β-mediated EMT and aggravates airway collagen deposit. We also found that Ang-(1-7) erased the aggravation of TGF-β-mediated EMT and epithelial fibrosis upon chronic IH exposure. These findings provided new insights that the ACE2/Ang-(1-7)/Mas axis might be considered as a potential therapeutic target for patients with asthma and OSA.

Association of Angiotensin Modulators With the Course of Idiopathic Pulmonary Fibrosis

BACKGROUND

Angiotensin peptides have been implicated in idiopathic pulmonary fibrosis (IPF) pathogenesis. Angiotensin modulators are used to treat arterial hypertension, a frequent comorbidity of IPF. This post hoc analysis evaluated associations of antihypertensive treatments with disease-related outcomes in IPF.

METHODS

All patients randomized to placebo (n = 624) in the CAPACITY and ASCEND studies were categorized by antihypertensive treatment at baseline. Outcomes of disease progression (first occurrence of ≥ 10% absolute decline in % predicted FVC, ≥ 50-m decline in 6-min walk distance, or death) and all-cause mortality were assessed over 52 weeks.

RESULTS

At baseline, 111 and 121 patients were receiving an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin II receptor blocker (ARB), respectively; 392 were receiving neither. In multivariable analyses adjusted for differences in baseline characteristics compared with the non-ACEi/ARB group, ACEi treatment (hazard ratio [HR], 0.6 [95% CI, 0.4-0.9]; P = .026), but not ARB (HR, 0.9 [95% CI, 0.6-1.2]; P = .413), was associated with slower disease progression. Furthermore, the increase in all-cause mortality associated with cardiovascular disease was not observed in the ACEi group (HR, 1.1 [95% CI, 0.5-2.9]; P = .782), which presented a similar percentage of IPF-related mortality as the non-ACEi/ARB group (3.6% vs 3.6%). In contrast, patients in the ARB group had greater risk of all-cause mortality (HR, 2.5 [95% CI, 1.2-5.2]). These observations were validated in a pooled analysis that included patients from the INSPIRE trial.

CONCLUSIONS

Prospective clinical trials are needed to evaluate whether angiotensin modulators may be beneficial to clinical outcomes in IPF.

TRIAL REGISTRY

ClinicalTrials.gov; Nos.: NCT01366209, NCT00287716, NCT00287729, NCT00075998; URL: www.clinicaltrials.gov).

Targeting the renin-angiotensin system as novel therapeutic strategy for pulmonary diseases

The renin-angiotensin system (RAS) plays a major role in regulating electrolyte balance and blood pressure. RAS has also been implicated in the regulation of inflammation, proliferation and fibrosis in pulmonary diseases such as asthma, acute lung injury (ALI), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and pulmonary arterial hypertension (PAH). Current therapeutics suffer from some drawbacks like steroid resistance, limited efficacies and side effects. Novel intervention is definitely needed to offer optimal therapeutic strategy and clinical outcome. This review compiles and analyses recent investigations targeting RAS for the treatment of inflammatory lung diseases. Inhibition of the upstream angiotensin (Ang) I/Ang II/angiotensin receptor type 1 (AT₁R) pathway and activation of the downstream angiotensin-converting enzyme 2 (ACE2)/Ang (1-7)/Mas receptor pathway are two feasible strategies demonstrating efficacies in various pulmonary disease models. More recent studies favor the development of targeting the downstream ACE2/Ang (1-7)/Mas receptor pathway, in which diminazene aceturate, an ACE2 activator, GSK2586881, a recombinant ACE2, and AV0991, a Mas receptor agonist, showed much potential for further development. As the pathogenesis of pulmonary diseases is so complex that RAS modulation may be used alone or in combination with existing drugs like corticosteroids, pirfenidone/nintedanib or endothelin receptor antagonists for different pulmonary diseases. Personalized medicine through genetic screening and phenotyping for angiotensinogen or ACE would aid treatment especially for non-responsive patients. This review serves to provide an update on the latest development in the field of RAS targeting for pulmonary diseases, and offer some insights into future direction.