Prime editing in mice with an engineered pegRNA.

CRISPR editing involves double-strand breaks in DNA with attending insertions/deletions (indels) that may result in embryonic lethality in mice. The prime editing (PE) platform uses a prime editing guide RNA (pegRNA) and a Cas9 nickase fused to a modified reverse transcriptase to precisely introduce nucleotide substitutions or small indels without the unintended editing associated with DNA double-strand breaks. Recently, engineered pegRNAs (epegRNAs), with a 3'-extension that shields the primer-binding site of the pegRNA from nucleolytic attack, demonstrated superior activity over conventional pegRNAs in cultured cells. Here, we show the inability of three-component CRISPR or conventional PE to incorporate a nonsynonymous substitution in the Capn2 gene, expected to disrupt a phosphorylation site (S50A) in CAPN2. In contrast, an epegRNA with the same protospacer correctly installed the desired edit in two founder mice, as evidenced by robust genotyping assays for the detection of subtle nucleotide substitutions. Long-read sequencing demonstrated sequence fidelity around the edited site as well as top-ranked distal off-target sites. Western blotting and histological analysis of lipopolysaccharide-treated lung tissue revealed a decrease in phosphorylation of CAPN2 and notable alleviation of inflammation, respectively. These results demonstrate the first successful use of an epegRNA for germline transmission in an animal model and provide a solution to targeting essential developmental genes that otherwise may be challenging to edit.

[International research progress of risk factors, diagnosis and management in early chronic obstructive pulmonary disease].

Chronic obstructive pulmonary disease (COPD) has a high global morbidity and mortality and a severe disease burden, yet progress in treatment and prevention has been slow in recent decades. Early COPD has few symptoms and is severely underdiagnosed and undertreated; it is crucial to search for effective clues of early COPD and provide management interventions. By reviewing the definition, risk factors, diagnosis and management interventions, this study explores the disease evolution of early-stage COPD, which can help clinical practice to develop more effective preventive and therapeutic strategies for stopping or slowing down the natural progression of the disease, improving the long-term prognosis, and reducing the disease burden.

Calpain Promotes LPS-induced Lung Endothelial Barrier Dysfunction via Cleavage of Talin.

Acute lung injury (ALI) is characterized by lung vascular endothelial cell (EC) barrier compromise resulting in increased endothelial permeability and pulmonary edema. The infection of gram-negative bacteria that produce toxins like LPS is one of the major causes of ALI. LPS activates Toll-like receptor 4, leading to cytoskeleton reorganization, resulting in lung endothelial barrier disruption and pulmonary edema in ALI. However, the signaling pathways that lead to the cytoskeleton reorganization and lung microvascular EC barrier disruption remain largely unexplored. Here we show that LPS induces calpain activation and talin cleavage into head and rod domains and that inhibition of calpain attenuates talin cleavage, RhoA activation, and pulmonary EC barrier disruption in LPS-treated human lung microvascular ECs in vitro and lung EC barrier disruption and pulmonary edema induced by LPS in ALI in vivo. Moreover, overexpression of calpain causes talin cleavage and RhoA activation, myosin light chain (MLC) phosphorylation, and increases in actin stress fiber formation. Furthermore, knockdown of talin attenuates LPS-induced RhoA activation and MLC phosphorylation and increased stress fiber formation and mitigates LPS-induced lung microvascular endothelial barrier disruption. Additionally, overexpression of talin head and rod domains increases RhoA activation, MLC phosphorylation, and stress fiber formation and enhances lung endothelial barrier disruption. Finally, overexpression of cleavage-resistant talin mutant reduces LPS-induced increases in MLC phosphorylation in human lung microvascular ECs and attenuates LPS-induced lung microvascular endothelial barrier disruption. These results provide the first evidence that calpain mediates LPS-induced lung microvascular endothelial barrier disruption in ALI via cleavage of talin.

Readmission rate for acute exacerbation of chronic obstructive pulmonary disease: A systematic review and meta-analysis.

BACKGROUND: The readmission rate following hospitalization for chronic obstructive pulmonary disease (COPD) exacerbations is extremely high and has become a common and challenging clinical problem. This study aimed to systematically summarize COPD readmission rates for acute exacerbations and their underlying risk factors. METHODS: A comprehensive search was performed using PubMed, Embase, Cochrane Library, and Web of Science, published from database inception to April 2, 2022. Methodological quality was evaluated using the Newcastle-Ottawa Scale (NOS). We used a random-effects model or a fixed-effects model to estimate the pooled COPD readmission rate for acute exacerbations and underlying risk factors. RESULTS: A total of 46 studies were included, of which 24, 7, 17, 7, and 20 summarized the COPD readmission rates for acute exacerbations within 30, 60, 90, 180, and 365 days, respectively. The pooled 30-, 60-, 90-, 180-, and 365-day readmission rates were 11%, 17%, 17%, 30%, and 37%, respectively. The study design type, age stage, WHO region, and length of stay (LOS) were initially considered to be sources of heterogeneity. We also identified potential risk factors for COPD readmission, including male sex, number of hospitalizations in the previous year, LOS, and comorbidities such as heart failure, tumor or cancer, and diabetes, whereas obesity was a protective factor. CONCLUSIONS: Patients with COPD had a high readmission rate for acute exacerbations, and potential risk factors were identified. Therefore, we should propose clinical interventions and adjust or targeted the control of avoidable risk factors to prevent and reduce the negative impact of COPD readmission. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, identifier CRD42022333581.

Assessment of Completeness of Reporting in Randomized Controlled Trials of Acupuncture Therapy for Chronic Obstructive Pulmonary Disease.

Objective: To assess the completeness of reporting in randomized controlled trials (RCTs) of acupuncture therapy (AT) for chronic obstructive pulmonary disease (COPD). Methods: We systematically searched PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Chongqing VIP (CQVIP), WANFANG Data, and China Biology Medicine (CBM) for studies published from their inception to May 8, 2021. The completeness of reporting was evaluated by CONSORT statement and STRICTA guidelines. Univariate and multivariate regression analyses were performed to preliminarily explore the factors related to completeness of reporting. Results: A total of 44 RCTs were included. The overall quality score (OQS) based on the CONSORT statement and STRICTA guidelines ranged from 3 to 26 and 7 to 14, with a median of 10 and 11, respectively. Among the 35 items of the CONSORT statement, 10 items were fully reported with reporting rate > 70%, and 11 items were poorly reported at a rate < 5%. Among the 17 items of the STRICTA guidelines, 10 items were adequately reported with > 70%, and only 3 items were incompletely reported at a rate < 20%. The agreement of most items was determined as "good", "substantial", or "moderate". By regression analysis, publication language (ß coefficient: 6.432, 95% CI: 3.202 to 9.663, P <0.001) and funding source (ß coefficient: 3.159, 95% CI: 1.045 to 5.273, P =0.004) acted as independent predictors of completeness of reporting according to the CONSORT statement. However, no variables associated with the STRICTA guidelines were identified. Conclusion: The completeness of reporting of AT for COPD was inadequate. The condition relatively improved for trials with publication in the English language and funding source. By recommendation, reports should be strictly standardized in accordance with the CONSORT statement and STRICTA guidelines to improve the clinical research evidence of AT for COPD.

Prevalence of Pulmonary Embolism and Deep Venous Thromboembolism in Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

Background: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) increases the risk of pulmonary embolism (PE) and deep venous thrombosis (DVT). AECOPD combined with PE and DVT poses challenges for treatment and management. This necessitates prevention and management to estimate the overall prevalence of PE and DVT among patients with AECOPD and to identify the risk factors. Methods: We searched the PubMed, Embase, and Cochrane Library databases from their inception to January 9, 2021 and extracted the data from the included studies. The risk of bias was assessed for each study. We separately calculated the prevalence of PE and DVT in patients with AECOPD. Subgroup analysis and meta-regression analyses were performed to determine the sources of heterogeneity. Furthermore, we assessed the publication bias. Results: The meta-analysis included 20 studies involving 5,854 people. The overall prevalence of PE and DVT among patients with AECOPD was 11% (95% CI: 0.06-0.17) and 9% (95% CI: 0.06-0.12), respectively. Subgroup analysis demonstrated that the prevalence of PE among patients with AECOPD was 12, 2, 7, and 16% in the European, South-East Asia, Western Pacific, and Eastern Mediterranean regions, respectively, and the DVT was 10, 9, 9, and 4%, respectively. The prevalence of PE among patients with AECOPD aged ≥ 70 and <70 years old was 6 and 15%, respectively, and the DVT was 8 and 9%, respectively. The prevalence of PE among patients with AECOPD diagnosed within 48 h and other times (beyond 48 h or not mentioned) was 16 and 6%, respectively, and DVT was 10 and 7%, respectively. Conclusion: The pooled prevalence of PE and DVT among patients with AECOPD was insignificantly different between the different age groups and the WHO regions. However, the early diagnosis was associated with a higher prevalence of PE. Clinicians and the public need to further improve the awareness of prevention and management for PE and DVT among patients with AECOPD. Systematic Review Registration: PROSPERO, identifier CRD42021260827.

HDAC6 Activates ERK in Airway and Pulmonary Vascular Remodeling of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a multisystemic respiratory disease that is associated with progressive airway and pulmonary vascular remodeling due to the increased proliferation of bronchial smooth muscles cells (BSMCs) and pulmonary arterial smooth muscle cells (PASMCs) and the overproduction of extracellular matrix (e.g., collagen). Cigarette smoke (CS) and several mediators, such as PDGF (platelet-derived growth factor) and IL-6, play critical roles in COPD pathogenesis. HDAC6 has been shown to be implicated in vascular remodeling. However, the role of airway HDAC6 signaling in pulmonary vascular remodeling in COPD and the underlying mechanisms remain undetermined. Here, we show that HDAC6 expression is upregulated in the lungs of patients with COPD and a COPD animal model. We also found that CS extract (CSE), PDGF, and IL-6 increase the protein levels and activation of HDAC6 in BSMCs and PASMCs. Furthermore, CSE and these stimulants induced deacetylation and phosphorylation of ERK1/2 and increased collagen synthesis and BSMC and PASMC proliferation, which were outcomes that were prevented by HDAC6 inhibition. Inhibition of ERK1/2 also diminished the CSE-, PDGF-, and IL-6-caused elevation in collagen levels and cell proliferation. Pharmacologic HDAC6 inhibition with tubastatin A prevented the CS-stimulated increases in the thickness of the bronchial and pulmonary arterial wall, airway resistance, emphysema, and right ventricular systolic pressure and right ventricular hypertrophy in a rat model of COPD. These data demonstrate that the upregulated HDAC6 governs the collagen synthesis and BSMC and PASMC proliferation that lead to airway and vascular remodeling in COPD.

Imaging findings of primary pulmonary synovial sarcoma with secondary distant metastases: A case report.

BACKGROUND: Synovial sarcoma (SS) accounting for 6%-10% of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs. Primary pulmonary SS (PPSS) is rare and has a poor prognosis. Cases of secondary distant metastases of PPSS occur rarely and there is a lack of corresponding imaging reports. We summarized the imaging findings of PPSS with multiple metastases confirmed by surgery and pathology, and shared valuable information on PPSS. CASE SUMMARY: A 43-year-old female patient had a solid space occupying lesion in the right upper lobe of the lung. The results of a hemogram, erythrocyte sedimentation rate (ESR) and tumor markers were all within the normal range, tuberculin skin test (5 TU PPD) was negative (-). Chest computed tomography examination showed similar round soft tissue density in the posterior segment of the right upper lobe. Thoracoscopic-assisted wedge resection of the right upper lobe of the lung, right upper lobe resection and lymph node dissection were performed. Nine months after surgery, ultrasound examination showed multiple metastases on the chest wall and kidney. CONCLUSION: PPSS is a rare malignant lung tumor with strong invasiveness, early distant metastasis and poor prognosis. There are very few imaging reports. PPSS is often manifested as irregular tumor and calcification, and the metastases have extremely low echo on ultrasonography. Contrast-enhanced ultrasound indicates that the arterial phase of tumor metastases shows rapid centripetal high enhancement, manifested as "fast forward and fast regression".

Low-Power Distributed Data Flow Anomaly-Monitoring Technology for Industrial Internet of Things.

. In recent years, the industrial use of the internet of things (IoT) has been constantly growing and is now widespread. Wireless sensor networks (WSNs) are a fundamental technology that has enabled such prevalent adoption of IoT in industry. WSNs can connect IoT sensors and monitor the working conditions of such sensors and of the overall environment, as well as detect unexpected system events in a timely and accurate manner. Monitoring large amounts of unstructured data generated by IoT devices and collected by the big-data analytics systems is a challenging task. Furthermore, detecting anomalies within the vast amount of data collected in real time by a centralized monitoring system is an even bigger challenge. In the context of the industrial use of the IoT, solutions for monitoring anomalies in distributed data flow need to be explored. In this paper, a low-power distributed data flow anomaly-monitoring model (LP-DDAM) is proposed to mitigate the communication overhead problem. As the data flow monitoring system is only interested in anomalies, which are rare, and the relationship among objects in terms of the size of their attribute values remains stable within any specific period of time, LP-DDAM integrates multiple objects as a complete set for processing, makes full use of the relationship among the objects, selects only one "representative" object for continuous monitoring, establishes certain constraints to ensure correctness, and reduces communication overheads by maintaining the overheads of constraints in exchange for a reduction in the number of monitored objects. Experiments on real data sets show that LP-DDAM can reduce communication overheads by approximately 70% when compared to an equivalent method that continuously monitors all objects under the same conditions.

Reactive Oxygen Species-Dependent Calpain Activation Contributes to Airway and Pulmonary Vascular Remodeling in Chronic Obstructive Pulmonary Disease.

Aims: Airway and pulmonary vascular remodeling is an important pathological feature in the pathogenesis of chronic obstructive pulmonary disease (COPD). Tobacco smoke (TS) induces the production of large amounts of reactive oxygen species (ROS) in COPD lungs. We investigated how ROS lead to airway and pulmonary vascular remodeling in COPD. Results: We used in vitro bronchial and pulmonary artery smooth muscle cells (BSMCs and PASMCs), in vivo TS-induced COPD rodent models, and lung tissues of COPD patients. We found that H2O2 and TS extract (TSE) induced calpain activation in BSMCs and PASMCs. Calpain activation was elevated in smooth muscle of bronchi and pulmonary arterioles in COPD patients and TS-induced COPD rodent models. Calpain inhibition attenuated H2O2- and TSE-induced collagen synthesis and proliferation of BSMCs and PASMCs. Exposure to TS causes increases in airway resistance, right ventricular systolic pressure (RVSP), and thickening of bronchi and pulmonary arteries. Calpain inhibition by smooth muscle-specific knockout of calpain and the calpain inhibitor MDL28170 attenuated increases in airway resistance, RVSP, and thickening of bronchi and pulmonary arteries. Moreover, smooth muscle-specific knockout of calpain did not reduce TS-induced emphysema in the mouse model, but MDL28170 did reduce TS-induced emphysema in the rat model. Innovation: This study provides the first evidence that ROS-induced calpain activation contributes to airway and pulmonary vascular remodeling in TS-induced COPD. Calpain might be a novel therapeutic target for the treatment of COPD. Conclusion: These results indicate that ROS-induced calpain activation contributes to airway and pulmonary vascular remodeling and pulmonary hypertension in COPD.

PFKFB3 in Smooth Muscle Promotes Vascular Remodeling in Pulmonary Arterial Hypertension.

Rationale: Glycolytic shift is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). It remains unknown how glycolysis is increased and how increased glycolysis contributes to pulmonary vascular remodeling in PAH.Objectives: To determine whether increased glycolysis is caused by 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) and how PFKFB3-driven glycolysis induces vascular remodeling in PAH.Methods: PFKFB3 levels were measured in pulmonary arteries of patients and animals with PAH. Lactate levels were assessed in lungs of animals with PAH and in pulmonary artery smooth muscle cells (PASMCs). Genetic and pharmacologic approaches were used to investigate the role of PFKFB3 in PAH.Measurements and Main Results: Lactate production was elevated in lungs of PAH rodents and in platelet-derived growth factor-treated PASMCs. PFKFB3 protein was higher in pulmonary arteries of patients and rodents with PAH, in PASMCs of patients with PAH, and in platelet-derived growth factor-treated PASMCs. PFKFB3 inhibition by genetic disruption and chemical inhibitor attenuated phosphorylation/activation of extracellular signal-regulated kinase (ERK1/2) and calpain-2, and vascular remodeling in PAH rodent models, and reduced platelet-derived growth factor-induced phosphorylation/activation of ERK1/2 and calpain-2, collagen synthesis and proliferation of PASMCs. ERK1/2 inhibition attenuated phosphorylation/activation of calpain-2, and vascular remodeling in Sugen/hypoxia PAH rats, and reduced lactate-induced phosphorylation/activation of calpain-2, collagen synthesis, and proliferation of PASMCs. Calpain-2 inhibition reduced lactate-induced collagen synthesis and proliferation of PASMCs.Conclusions: Upregulated PFKFB3 mediates collagen synthesis and proliferation of PASMCs, contributing to vascular remodeling in PAH. The mechanism is through the elevation of glycolysis and lactate that results in the activation of calpain by ERK1/2-dependent phosphorylation of calpain-2.

Distribution-Sensitive Unbalanced Data Oversampling Method for Medical Diagnosis.

Aiming at the problem of low accuracy of classification learning algorithm caused by serious imbalance of sample set in medical diagnostic application, this paper proposes a distribution-sensitive oversampling algorithm for imbalanced data. The algorithm accurately divides the minority samples into noise samples, unstable samples, boundary samples and stable samples according to the location of the minority samples. Different samples are processed differently to select the most suitable sample for the synthesis of new samples. In the case of sample synthesis, a distribution-sensitive sample synthesis method is adopted. Different sample synthesis methods are selected according to their different distance from the surrounding minority samples, so as to ensure that the newly synthesized samples have the same characteristics with the original minority samples. The real medical diagnostic data test shows that this algorithm improves the accuracy rate of classification learning algorithm compared with the existing sampling algorithms, especially for the accuracy rate and recall rate of minority classes.

Transcutaneous electric nerve stimulation over acupoints for chronic obstructive pulmonary disease: Protocol for a systematic review and meta-analysis.

BACKGROUND: There is a limited evidence concerning the efficacy of transcutaneous electric nerve stimulation over acupoints (Acu-TENS) for chronic obstructive pulmonary disease (COPD). Thus, this review aims to systematically determine the effect of Acu-TENS on COPD. METHODS: PubMed, Embase, The Cochrane Library, Web of Science, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Chongqing VIP, and Wanfang Data will be searched from their inception to May 10, 2018. Randomized controlled trials that evaluated the effect of Acu-TENS on patients with COPD will be included. The primary outcome measures will include 6-minute walk distance and dyspnea visual analog scale scores. The secondary outcome measures will include lung function and St George's Respiratory Questionnaire. Study selection, data extraction, and risk of bias assessment will be independently undertaken, respectively. Statistical analysis will be conducted by RevMan software (version 5.3). RESULTS: This systematic review will provide a detailed summary of current evidences related to the efficacy of Acu-TENS in improving exercise capacity, breathlessness, quality of life, and lung function of patients with COPD. CONCLUSION: This evidence may be useful to clinicians, patients, and health policy makers with regard to the use of Acu-TENS in the treatment of COPD. ETHICS AND DISSEMINATION: This review will not gather original data; hence, ethical approval is not required. The results will be disseminated through a peer-reviewed publication or conference presentations.

Calpain-2 activates Akt via TGF-ß1-mTORC2 pathway in pulmonary artery smooth muscle cells.

Calpain is a family of calcium-dependent nonlysosomal neutral cysteine endopeptidases. Akt is a serine/threonine kinase that belongs to AGC kinases and plays important roles in cell survival, growth, proliferation, angiogenesis, and cell metabolism. Both calpain and Akt are the downstream signaling molecules of platelet-derived growth factor (PDGF) and mediate PDGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. We found that inhibitions of calpain-2 by using calpain inhibitor MDL28170 and calpain-2 small interfering RNA attenuated Akt phosphorylations at serine-473 (S473) and threonine-308 (T308), as well as collagen synthesis and cell proliferation of PASMCs induced by PDGF. Overexpression of calpain-2 in PASMCs induced dramatic increases in Akt phosphorylations at S473 and T308. Moreover, knockout of calpain attenuated Akt phosphorylations at S473 and T308 in smooth muscle of pulmonary arterioles of mice with chronic hypoxic pulmonary hypertension. The cell-permeable-specific transforming growth factor (TGF)-ß receptor inhibitor SB431542 attenuated Akt phosphorylations at both S473 and T308 induced by PDGF and by overexpressed calpain-2 in PASMCs. Furthermore, SB-431452 and knocking down activin receptor-like kinase-5 significantly reduced PDGF-induced collagen synthesis and cell proliferation of PASMCs. Nevertheless, neutralizing extracellular TGF-ß1 using a cell-impermeable TGF-ß1 neutralizing antibody did not affect PDGF-induced Akt phosphorylations at S473 and T308. Furthermore, inhibition of mammalian target of rapamycin complex 2 (mTORC2) by knocking down its component protein Rictor prevented Akt phosphorylations at S473 and T308 induced by PDGF and by overexpressed calpain-2. These data provide first evidence supporting that calpain-2 upregulates PDGF-induced Akt phosphorylation in pulmonary vascular remodeling via an intracrine TGF-ß1/mTORC2 mechanism.

Activation of Calpain-2 by Mediators in Pulmonary Vascular Remodeling of Pulmonary Arterial Hypertension.

Calpain mediates collagen synthesis and cell proliferation and plays an important role in pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). In the present study, we investigated whether and how calpain is activated by PAH mediators in pulmonary artery smooth muscle cells (PASMCs). These data show that smooth muscle-specific knockout of calpain attenuated and knockout of calpastatin potentiated pulmonary vascular remodeling and pulmonary hypertension. Treatment of PASMCs with the PAH mediators platelet-derived growth factor (PDGF), serotonin, H2O2, endothelin-1, and IL-6 caused significant increases in calpain activity, cell proliferation, and collagen-I protein level without changes in protein levels of calpain-1 and -2. The calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) (BAPTA/AM) did not affect calpain activation, but the extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 and knocking down of calpain-2 prevented calpain activation in PAH mediator-treated PASMCs. Mass spectrometry data showed that the phosphorylation of calpain-2 at serine (Ser) 50 was increased and the phosphorylation of calpain-2 at Ser369 was decreased in PDGF-treated PASMCs. The PDGF-induced increase in Ser50 phosphorylation of calpain-2 was prevented by PD98059, whereas dephosphorylation of calpain-2 at Ser369 was blocked by the protein phosphatase 2A inhibitor fostriecin. Furthermore, smooth muscle of pulmonary arteries in PAH animal models and patients with PAH showed higher levels of phospho-Ser50-calpain-2 (P-Ser50) and lower levels of phospho-Ser369-calpain-2 (P-Ser369). These data support that calpain modulates pulmonary vascular remodeling in PAH. PAH mediator-induced activation of calpain is caused by ERK1/2-dependent phosphorylation of calpain-2 at Ser50 and protein phosphatase 2A-dependent dephosphorylation of calpain-2 at Ser369 in pulmonary vascular remodeling of PAH.

Increasing muscle mass improves vascular function in obese (db/db) mice.

BACKGROUND: A sedentary lifestyle is an independent risk factor for cardiovascular disease and exercise has been shown to ameliorate this risk. Inactivity is associated with a loss of muscle mass, which is also reversed with isometric exercise training. The relationship between muscle mass and vascular function is poorly defined. The aims of the current study were to determine whether increasing muscle mass by genetic deletion of myostatin, a negative regulator of muscle growth, can influence vascular function in mesenteric arteries from obese db/db mice. METHODS AND RESULTS: Myostatin expression was elevated in skeletal muscle of obese mice and associated with reduced muscle mass (30% to 50%). Myostatin deletion increased muscle mass in lean (40% to 60%) and obese (80% to 115%) mice through increased muscle fiber size (P<0.05). Myostatin deletion decreased adipose tissue in lean mice, but not obese mice. Markers of insulin resistance and glucose tolerance were improved in obese myostatin knockout mice. Obese mice demonstrated an impaired endothelial vasodilation, compared to lean mice. This impairment was improved by superoxide dismutase mimic Tempol. Deletion of myostatin improved endothelial vasodilation in mesenteric arteries in obese, but not in lean, mice. This improvement was blunted by nitric oxide (NO) synthase inhibitor l-NG-nitroarginine methyl ester (l-NAME). Prostacyclin (PGI2)- and endothelium-derived hyperpolarizing factor (EDHF)-mediated vasodilation were preserved in obese mice and unaffected by myostatin deletion. Reactive oxygen species) was elevated in the mesenteric endothelium of obese mice and down-regulated by deletion of myostatin in obese mice. Impaired vasodilation in obese mice was improved by NADPH oxidase inhibitor (GKT136901). Treatment with sepiapterin, which increases levels of tetrahydrobiopterin, improved vasodilation in obese mice, an improvement blocked by l-NAME. CONCLUSIONS: Increasing muscle mass by genetic deletion of myostatin improves NO-, but not PGI2- or EDHF-mediated vasodilation in obese mice; this vasodilation improvement is mediated by down-regulation of superoxide.

NADPH oxidase 4 is expressed in pulmonary artery adventitia and contributes to hypertensive vascular remodeling.

OBJECTIVE: Pulmonary hypertension (PH) is a progressive disease arising from remodeling and narrowing of pulmonary arteries (PAs) resulting in high pulmonary blood pressure and ultimately right ventricular failure. Elevated production of reactive oxygen species by NADPH oxidase 4 (Nox4) is associated with increased pressure in PH. However, the cellular location of Nox4 and its contribution to aberrant vascular remodeling in PH remains poorly understood. Therefore, we sought to identify the vascular cells expressing Nox4 in PAs and determine the functional relevance of Nox4 in PH. APPROACH AND RESULTS: Elevated expression of Nox4 was detected in hypertensive PAs from 3 rat PH models and human PH using qualititative real-time reverse transcription polymerase chain reaction, Western blot, and immunofluorescence. In the vascular wall, Nox4 was detected in both endothelium and adventitia, and perivascular staining was prominently increased in hypertensive lung sections, colocalizing with cells expressing fibroblast and monocyte markers and matching the adventitial location of reactive oxygen species production. Small-molecule inhibitors of Nox4 reduced adventitial reactive oxygen species generation and vascular remodeling as well as ameliorating right ventricular hypertrophy and noninvasive indices of PA stiffness in monocrotaline-treated rats as determined by morphometric analysis and high-resolution digital ultrasound. Nox4 inhibitors improved PH in both prevention and reversal protocols and reduced the expression of fibroblast markers in isolated PAs. In fibroblasts, Nox4 overexpression stimulated migration and proliferation and was necessary for matrix gene expression. CONCLUSION: These findings indicate that Nox4 is prominently expressed in the adventitia and contributes to altered fibroblast behavior, hypertensive vascular remodeling, and development of PH.

Caveolin-1 is a negative regulator of NADPH oxidase-derived reactive oxygen species.

Changes in the expression and function of caveolin-1 (Cav-1) have been proposed as a pathogenic mechanism underlying many cardiovascular diseases. Cav-1 binds to and regulates the activity of numerous signaling proteins via interactions with its scaffolding domain. In endothelial cells, Cav-1 has been shown to reduce reactive oxygen species (ROS) production, but whether Cav-1 regulates the activity of NADPH oxidases (Noxes), a major source of cellular ROS, has not yet been shown. Herein, we show that Cav-1 is primarily expressed in the endothelium and adventitia of pulmonary arteries (PAs) and that Cav-1 expression is reduced in isolated PAs from multiple models of pulmonary artery hypertension (PH). Reduced Cav-1 expression correlates with increased ROS production in the adventitia of hypertensive PA. In vitro experiments revealed a significant ability of Cav-1 and its scaffolding domain to inhibit Nox1-5 activity and it was also found that Cav-1 binds to Nox5 and Nox2 but not Nox4. In addition to posttranslational actions, in primary cells, Cav-1 represses the mRNA and protein expression of Nox2 and Nox4 through inhibition of the NF-κB pathway. Last, in a mouse hypoxia model, the genetic ablation of Cav-1 increased the expression of Nox2 and Nox4 and exacerbated PH. Together, these results suggest that Cav-1 is a negative regulator of Nox function via two distinct mechanisms, acutely through direct binding and chronically through alteration of expression levels. Accordingly, the loss of Cav-1 expression in cardiovascular diseases such as PH may account for the increased Nox activity and greater production of ROS.

Endothelin-1 induces a glycolytic switch in pulmonary arterial endothelial cells via the mitochondrial translocation of endothelial nitric oxide synthase.

Recent studies have indicated that, during the development of pulmonary hypertension (PH), there is a switch from oxidative phosphorylation to glycolysis in the pulmonary endothelium. However, the mechanisms underlying this phenomenon have not been elucidated. Endothelin (ET)-1, an endothelial-derived vasoconstrictor peptide, is increased in PH, and has been shown to play an important role in the oxidative stress associated with PH. Thus, in this study, we investigated whether there was a potential link between increases in ET-1 and mitochondrial remodeling. Our data indicate that ET-1 induces the redistribution of endothelial nitric oxide synthase (eNOS) from the plasma membrane to the mitochondria in pulmonary arterial endothelial cells, and that this was dependent on eNOS uncoupling. We also found that ET-1 disturbed carnitine metabolism, resulting in the attenuation of mitochondrial bioenergetics. However, ATP levels were unchanged due to a compensatory increase in glycolysis. Further mechanistic investigations demonstrated that ET-1 mediated the redistribution of eNOS via the phosphorylation of eNOS at Thr495 by protein kinase C δ. In addition, the glycolytic switch appeared to be dependent on mitochondrial-derived reactive oxygen species that led to the activation of hypoxia-inducible factor signaling. Finally, the cell culture data were confirmed in vivo using the monocrotaline rat model of PH. Thus, we conclude that ET-1 induces a glycolytic switch in pulmonary arterial endothelial cells via the redistribution of uncoupled eNOS to the mitochondria, and that preventing this event may be an approach for the treatment of PH.

The role of RhoA and cytoskeleton in myofibroblast transformation in hyperoxic lung fibrosis.

Myofibroblast transformation is a key process in the pathogenesis of lung fibrosis. We have previously reported that hyperoxia induces RhoA activation in HFL-1 lung fibroblasts and RhoA mediates collagen synthesis in hyperoxic lung fibrosis. In this study, we investigated the role of RhoA and actin cytoskeleton in hyperoxia-induced myofibroblast transformation. Exposure of HFL-1 lung fibroblasts to hyperoxia stimulated actin filament formation, shift of G-actin to F-actin, nuclear colocalization of myocardin-related transcription factor-A (MRTF-A), recruitment of MRTF-A to the α-smooth muscle actin (α-SMA) gene promoter, myofibroblast transformation, and collagen-I synthesis. Inhibition of RhoA by C3 transferase CT-04 or dominant-negative RhoA mutant T19N, and inhibition of ROCK by Y27632, prevented myofibroblast transformation and collagen-I synthesis. Moreover, inhibition of RhoA by CT-04 prevented hyperoxia-induced actin filament formation, shift of G-actin to F-actin, and nuclear colocalization of MRTF-A. In addition, disrupting actin filaments with cytochalasin D or scavenging reactive oxygen species (ROS) with tiron attenuated actin filament formation, nuclear colocalization of MRTF-A, myofibroblast transformation, and collagen-I synthesis. Furthermore, overexpression of constitutively active RhoA mutant Q63L or stabilization of actin filaments recapitulated the effects of hyperoxia on the actin cytoskeleton and nuclear colocalization of MRTF-A, myofibroblast transformation, and collagen-I synthesis. Interestingly, knocking down MRTF-A prevented hyperoxia-induced increase in the recruitment of MRTF-A to the serum response factor transcriptional complex on the α-SMA gene promoter, myofibroblast transformation, and collagen-I synthesis. Finally, Y27632 and tiron attenuated hyperoxia-induced increases in α-SMA and collagen-I in mouse lungs. Together, these results indicate that the actin cytoskeletal reorganization due to the ROS/RhoA-ROCK pathway mediates myofibroblast transformation and collagen synthesis in lung fibrosis of oxygen toxicity. MRTF-A contributes to the regulatory effect of the actin cytoskeleton on myofibroblast transformation during hyperoxia.