The protocol of enhanced recovery after cardiac surgery in adult patients: A stepped wedge cluster randomized trial

BACKGROUND

The enhanced recovery after cardiac surgery is a bundle of measurements from preoperative to postoperative phases to improve patients' recovery.

METHODS

This study is a multicenter, stepwise design, cluster randomized controlled trial. About 3,600 patients presenting during control and intervention periods are eligible if they are aged from 18 to 80 years old awaiting elective cardiac surgery with cardiopulmonary bypass (CPB). About 5 centers are randomly assigned to staggered start dates for one-way crossover from the control phase to the intervention phase. In the intervention periods, patients will receive ERAS strategy including preoperative, intraoperative, and postoperative approaches. During the control phase, patients receive usual care. The primary outcome consists of major adverse cardiac and cerebrovascular events (MACCEs), postoperative pulmonary complications (PPCs), and acute kidney injury (AKI).

DISCUSSION

This study aims to compare the application of ERAS management protocol and traditional management protocol in adult cardiac surgery under extracorporeal circulation.

The protocol of Enhanced Recovery After Cardiac Surgery (ERACS) in congenital heart disease: a stepped wedge cluster randomized trial

BACKGROUND

The Enhanced Recovery After Cardiac Surgery (ERACS) programs are comprehensive multidisciplinary interventions to improve patients' recovery. The application of the ERAS principle in pediatric patients has not been identified completely.

METHODS

This study is a multicenter, stepwise design, cluster randomized controlled trial. 3030 patients presenting during control and intervention periods are eligible if they are aged from 28 days to 6 years old and awaiting elective correction surgery of congenital heart disease with cardiopulmonary bypass. 5 centers are randomly assigned to staggered start dates for one-way crossover from the control phase to the intervention phase. In the intervention periods, patients will receive a bundle strategy including preoperative, intraoperative, and postoperative approaches. During the control phase, patients receive the usual care. The primary outcome consists of major adverse cardiac and cerebrovascular events (MACCEs), postoperative pulmonary complications (PPCs), and acute kidney injury (AKI).

DISCUSSION

This study aims to explore whether the bundle of ERAS measurements could improve patients' recovery in congenital heart surgery.

TRIAL REGISTRATION

http://www.

CLINICALTRIALS

gov . (NCT05914103).

Progress in neurorehabilitation research and the support by the National Natural Science Foundation of China from 2010 to 2022

The National Natural Science Foundation of China is one of the major funding agencies for neurorehabilitation research in China. This study reviews the frontier directions and achievements in the field of neurorehabilitation in China and worldwide. We used data from the Web of Science Core Collection (WoSCC) database to analyze the publications and data provided by the National Natural Science Foundation of China to analyze funding information. In addition, the prospects for neurorehabilitation research in China are discussed. From 2010 to 2022, a total of 74,220 publications in neurorehabilitation were identified, with there being an overall upward tendency. During this period, the National Natural Science Foundation of China has funded 476 research projects with a total funding of 192.38 million RMB to support neurorehabilitation research in China. With the support of the National Natural Science Foundation of China, China has made some achievements in neurorehabilitation research. Research related to neurorehabilitation is believed to be making steady and significant progress in China.

Effect of hemoglobin and oxygen saturation on adverse outcomes in children with tetralogy of fallot: a retrospective observational study

BACKGROUND

Tetralogy of Fallot (TOF) is a common cyanotic congenital heart malformation that carries a high risk of right-to-left shunting. Anemia is characterized by decreased hemoglobin (Hb) levels that can affect tissue oxygen delivery and impact postoperative recovery in patients. Chronic hypoxia caused by right-to-left shunting of TOF could lead to compensatory increases in Hb to maintain systemic oxygen balance. This study aims to investigate whether preoperative Hb and blood oxygen saturation (SpO2) can predict adverse outcomes in children undergoing corrective surgery for TOF.

METHODS

This retrospective study included patients under 18 years of age who underwent corrective surgery for TOF at Fuwai Hospital between January 2016 and December 2018. Adverse outcomes, including in-hospital death, extracorporeal membrane oxygenation implantation, ICU stay > 30 days, and severe complications, were considered as the primary outcome. Univariable and multivariable logistic analyses were performed to identify independent risk factors for adverse outcomes. Propensity score-matched (PSM) analysis was also conducted to minimize the confounding factors.

RESULTS

A total of 596 children were included in the study, of which 64 (10.7%) experienced adverse outcomes. Hb*SpO2 < aaHb was identified as an independent risk factor for adverse outcomes (OR = 2.241, 95% CI = 1.276-3.934, P = 0.005) after univariable and multivariable logistic analyses. PSM analysis further confirmed the association between Hb*SpO2 < aaHb and adverse outcomes. Patients with Hb*SpO2 < aaHb had a significantly higher incidence of postoperative adverse outcomes, longer time of mechanical ventilation, and hospital stay, as well as higher in-hospital costs.

CONCLUSIONS

Hb*SpO2 < aaHb is significantly associated with adverse outcomes in children undergoing corrective surgery for TOF. Clinicians can use this parameter to early identify high-risk children and optimize their postoperative management.

Impact of humid climate on rheumatoid arthritis faecal microbiome and metabolites

Studies have shown that high humidity is a condition that aggravates the pain of rheumatoid arthritis (RA), but the relevant mechanism is controversial. Currently, there is a lack of experimental animal studies on high humidity as an adverse factor related to the pathogenesis of RA. We used healthy SD rats and collagen-induced arthritis (CIA) rats to investigate the effects of high humidity on arthritis. Integrated metabolomics analyses of faeces and 16S rRNA sequencing of the faecal microbiota were performed to comprehensively assess the diversity of the faecal microbiota and metabolites in healthy and CIA rats. In this study, high humidity aggravated arthritis in CIA rats, which manifested as articular cartilage lesions, increased arthritis scores, and an increase in proinflammatory cytokines. High humidity had a certain effect on the articular cartilage extent, arthritis score and proinflammatory cytokines of healthy rats as well. Furthermore, high humidity caused significant changes in faecal microbes and metabolites in both healthy and CIA rats. 16S rRNA sequencing of faecal samples showed that high humidity increased the amount of inflammation-related bacteria in healthy and CIA rats. Faecal metabolomics results showed that high humidity significantly altered the level of faecal metabolites in healthy rats and CIA rats, and the changes in biological functions were mainly related to the inflammatory response and oxidative stress. Combined analysis showed that there was a strong correlation between the faecal microbiota and faecal metabolites. High humidity is an adverse factor for the onset and development of RA, and its mechanism is related to the inflammatory response and oxidative stress. However, the question of how high humidity impacts RA pathogenesis needs to be further investigated.

Evaluation of fluid responsiveness with dynamic superior vena cava collapsibility index in mechanically ventilated patients

BACKGROUND

This study aimed to evaluate the predictive accuracy of the superior vena cava collapsibility index measured by transesophageal echocardiography and compare the index with stroke volume variation measured by FloTrac™/Vigileo™ in mechanically ventilated patients.

METHODS

In the prospective study, a total of 60 patients were enrolled for elective general surgery under mechanical ventilation, where all patients received 10 ml/kg of Ringer's lactate. Five kinds of related data were recorded before and after the fluid challenge, including the superior vena cava collapsibility index (SVC-CI), the ratio of E/e', cardiac index (CI), stroke volume variation (SVV), and central venous pressure (CVP). Based on the collected data after the fluid challenge, we classified the patients as responders (FR group) if their CI increased by at least 15% and the rest were non-responders (NR).

RESULTS

Twenty-five of 52 (48%) of the patients were responders, and 27 were non-responders (52%). The SVC-CI was higher in the responders (41.90 ± 11.48 vs 28.92 ± 9.05%, P < 0.01). SVC-CI was significantly correlated with △CI _FloTrac (r = 0.568, P < 0.01). The area under the ROC curve (AUROC) of SVC-CI was 0.838 (95% CI 0.728 ~ 0.947, P < 0.01) with the optimal cutoff value of 39.4% (sensitivity 64%, specificity 92.6%). And there was no significant difference in E/e' between the two groups (P > 0.05). The best cutoff value for SVV was 12.5% (sensitivity 40%, specificity 89%) with the AUROC of 0.68 (95% CI 0.53 ~ 0.826, P < 0.05).

CONCLUSIONS

The SVC-CI and SVV can predict fluid responsiveness effectively in mechanically ventilated patients. And SVC-CI is superior in predicting fluid responsiveness compared with SVV. The E/e' ratio and CVP cannot predict FR effectively.

TRIAL REGISTRATION

Chinese clinical trial registry (ChiCTR2000034940).

Efficacy and safety of different doses of epidural morphine coadministered with low-concentration ropivacaine after cesarean section: A retrospective cohort study

Objective: The optimal dose of epidural morphine after cesarean section (CS) still remains unknown when combined with low-concentration ropivacaine based on a continuous basal infusion (CBI) mode. The aim of this study was to assess the impact of different dose of epidural morphine plus ropivacaine on maternal outcomes.

Materials and methods: Data of parturients who received epidural analgesia for CS at a teaching hospital from March 2021 to June 2022 were retrospectively collected. Parturients were divided into two groups (RM3 group and RM6 group) according to different medication regimens of morphine. The implementation of epidural analgesia was performed with 3 mg morphine in RM3 group and 6 mg morphine in RM6 group in combination with 0.1% ropivacaine via a CBI pump. The primary outcomes included pain intensity at rest and movement and the incidence of urinary retention and pruritus within postoperative 48 h. The secondary outcomes included the incidence and severity of postoperative nausea and vomiting (PONV) and pruritus, the rate of rescue analgesia and grading of motor Block.

Results: Totally, 531 parturients were eligible for the final analysis, with 428 and 103 parturients in the RM3 group and RM6 group, respectively. There were no statistically significant differences in the visual analogue scores (VAS) at rest and movement within postoperative 48 h between the two groups (all p &gt; 0.05). Compared with the RM6 group, the incidence of urinary retention was lower in the RM3 group within 48 h after CS (4.0% vs. 8.7%, p = 0.044). No significant difference was found in the incidence and severity of PONV and pruritus, the rate of rescue analgesia and grading of motor block between RM3 and RM6 groups.

Conclusion: Epidural 3 mg morphine plus 0.1% ropivacaine in a CBI mode can provide equal efficacy and have lower incidence of urinary retention compared with 6 mg morphine after CS.

Multitargeted drug design strategy for discovery of short-peptide-based HIV-1 entry inhibitors with high potency

The development of short-peptide-based inhibitors to prevent HIV-1 entry into the host cell has been rewarded with limited success. Herein, we report a multitarget-directed ligand strategy to generate a series of short-peptide HIV-1 entry inhibitors that integrated the pharmacological activities of a peptide fusion inhibitor able to disrupt HIV-1 gp41 glycoprotein hexameric coiled-coil assembly and a small-molecule CCR5 antagonist that blocks the interaction between HIV-1 and its coreceptor. Among these inhibitors, dual-target 23-residue peptides SP12T and SP12L displayed dramatically increased inhibitory activities against HIV-1 replication as compared to the marketed 36-residue peptide T20. Moreover, results suggested that SP12T and SP12L successfully performed a dual-targeting mechanism. It can be concluded that these short-peptide-based HIV-1 entry inhibitors have potential for further development as candidates for a novel multitarget therapy to treat HIV-1 infection.

Discovery of Pteridine-7(8H)-one Derivatives as Potent and Selective Inhibitors of Bruton's Tyrosine Kinase (BTK)

Bruton's tyrosine kinase (BTK) is an attractive therapeutic target in the treatment of cancer, inflammation, and autoimmune diseases. Covalent and noncovalent BTK inhibitors have been developed, among which covalent BTK inhibitors have shown great clinical efficacy. However, some of them could produce adverse effects, such as diarrhea, rash, and platelet dysfunction, which are associated with the off-target inhibition of ITK and EGFR. In this study, we disclosed a series of pteridine-7(8H)-one derivatives as potent and selective covalent BTK inhibitors, which were optimized from 3z, an EGFR inhibitor previously reported by our group. Among them, compound 24a exhibited great BTK inhibition activity (IC50 = 4.0 nM) and high selectivity in both enzymatic (ITK >250-fold, EGFR >2500-fold) and cellular levels (ITK >227-fold, EGFR 27-fold). In U-937 xenograft models, 24a significantly inhibited tumor growth (TGI = 57.85%) at a 50 mg/kg dosage. Accordingly, 24a is a new BTK inhibitor worthy of further development.

Discovery of pyrido[3,4-b]indol-1-one derivatives as novel non-covalent Bruton's tyrosine kinase (BTK) inhibitors

Bruton's tyrosine kinase (BTK) is an attractive target for the treatment of malignancy and inflammatory/autoimmune diseases. Most of the covalent BTK inhibitors would induce off-target side effects and drug resistance. To improve the drug safety of BTK inhibitors, non-covalent inhibitors have attracted more and more attention. We designed a series of novel pyrido[3,4-b]indol-1-one derivatives (N-A and N-B) via scaffold hopping from CGI-1746. The structure-activity relationship (SAR) of the newly-synthesized compounds was explored. The results showed that compounds 12 and 18 exhibited potent enzymatic potency against BTK with IC₅₀ values of 0.22 μM and 0.19 μM, respectively. In lymphoma cell lines U-937 cells and Ramos cells, compounds 12 and 18 displayed comparative antiproliferative activity with Ibrutinib. Moreover, compound 12 induced G1-phase cell cycle arrest and apoptosis in U-937 cells. And it could effectively inhibit tumor growth in U-937 xenograft mouse model (TGI = 41.90% at 50 mg/kg). In all, the new pyrido[3,4-b]indol-1-one derivatives have the antitumor potency by BTK inhibition and were worthy of further exploration.

Trends, composition and distribution of nurse workforce in China: a secondary analysis of national data from 2003 to 2018

OBJECTIVES

Given the increased ageing population and frequent epidemic challenges, it is vital to have the nurse workforce of sufficient quantity and quality. This study aimed to demonstrate the trends, composition and distribution of nurse workforce in China.

DESIGN

Secondary analysis using national public datasets in China from 2003 to 2018.

SETTING/PARTICIPANTS

National population, nurse workforce and physician workforce.

PRIMARY AND SECONDARY OUTCOME MEASURES

Frequency and proportion were used to demonstrate: (1) the longitudinal growth of nurse workforce; (2) the diversity of nurse workforce in gender, age, work experience and education level; and (3) the distribution of nurse workforce among provinces, rural-urban areas and hospital/community settings. The Gini coefficient and Theil L index were used to measure the inequality trends of nurse workforce.

RESULTS

The total number of nurses increased from 1.3 million to 4.1 million and the density increased from 1 to 2.94 per 1000 population over 2003-2018. The nurses to physician ratio changed from 0.65:1 to 1.14:1. The majority of the nurse workforce was female, under 35 years old, with less than 30 years of work experience, with an associate's degree and employed within hospitals. Central and eastern regions had more nurses and there were 5.08 nurses per 1000 population in urban areas while less than two in rural areas in 2018. The Gini coefficient and between-provincial Theil index experienced a consistent decline. Within-province inequality accounted for overall inequality has risen from 52.38% in 2010 to 71.43% in 2018 suggested that the differences of distribution are mainly reflected in urban and rural areas.

CONCLUSION

Chinese nurse workforce has been changed significantly in the past 15 years that may be associated with the reformations of policy, nursing education in China. Our study suggests current features in the nurse workforce and can be used to strengthen future health services.

A Prospective and Retrospective Clinical Controlled Observation of Chinese Herbal Decoction (SMLJ01) for Type 1 Gastric Neuroendocrine Tumors

INTRODUCTION

Type 1 gastric neuroendocrine tumors (g-NETs) have a good prognosis but a high recurrence rate.

AIM

To observe the clinical efficacy of the treatment of type 1 g-NETs with the Chinese herbal decoction SMLJ01.

MATERIALS AND METHODS

A prospective and retrospective, clinical, controlled observation was conducted in 4 Chinese centers from 2012 to 2019. Patients with type 1 g-NETs were nonrandomly divided into treatment and control groups after endoscopic treatment based on herbal treatment administered according to their wishes. The treatment group received oral SMLJ01, with follow-up every 6 to 12 months, while the control group received follow-up alone. Patient follow-up (via telephone) from 2012 to 2017 was mainly retrospective. All patients after 2017 were followed prospectively. The recurrence times and rates were compared after treatment for at least 6 months. Symptom improvements were evaluated in the treatment group. The follow-up ended on October 31, 2019.

RESULTS

During a median follow-up of 22 months (range: 2-86 months), the survival rate was 100%, and no metastases occurred. Twenty-one of the 82 treated patients (25.6%) had recurrence after a median of 22 months, and 22 of the 54 control patients (40.7%) had recurrence after a median of 8 months (P = .063). The Kaplan-Meier curve analysis showed that the patients in the treatment group had a significantly longer median recurrence-free survival (RFS) time than those in the control group (P = .001). The risk of recurrence in the treatment group was 0.38 relative to that in the control group (95% CI: 0.20-0.70). The symptom score of the patients after taking Chinese medicine was 19.5 (10.3, 28.0), which was significantly lower than before treatment (31.5 (19.3, 38.0)). The difference was statistically significant (P < .01).

CONCLUSION

SMLJ01, with the effects of soothing the liver, strengthening the spleen, increasing acid and harmonizing the stomach, may help reduce the recurrence rate, relieve symptoms and prolong the recurrence time in patients with type 1 g-NETs and is worthy of evaluation with further randomized research with large sample sizes and longer follow-up periods.

iTRAQ-based quantitative proteomics analysis of the hepatoprotective effect of melatonin on ANIT-induced cholestasis in rats

The therapeutic effects of melatonin on cholestatic liver injury have received widespread attention recently. The aim of the present study was to investigate the mechanisms of the anti-cholestatic effects of melatonin against α-naphthyl isothiocyanate (ANIT)-induced liver injury in rats and to screen for potential biomarkers of cholestasis through isobaric tags for relative and absolute quantitation (iTRAQ) proteomics. Rats orally received melatonin (100 mg/kg body weight) or an equivalent volume of 0.25% carboxymethyl cellulose sodium salt 12 h after intraperitoneal injection of ANIT (75 mg/kg) and were subsequently sacrificed at 36 h after injection. Liver biochemical indices were determined and liver tissue samples were stained using hematoxylin-eosin staining, followed by iTRAQ quantitative proteomics to identify potential underlying therapeutic mechanisms and biomarkers. The results suggested that the expression levels of alanine transaminase, aspartate aminotransferase, total bilirubin and direct bilirubin were reduced in the rats treated with melatonin. Histopathological observation indicated that melatonin was effective in the treatment of ANIT-induced cholestasis. iTRAQ proteomics results suggested that melatonin-mediated reduction in ANIT-induced cholestasis may be associated with enhanced antioxidant function and relieving abnormal fatty acid metabolism. According to pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes, the major metabolic pathways for the metabolism of melatonin are fatty acid degradation, the peroxisome proliferator-activated receptor signaling pathway, fatty acid metabolism, chemical carcinogenesis, carbon metabolism, pyruvate metabolism, fatty acid biosynthesis and retinol metabolism, as well as drug metabolism via cytochrome P450. Malate dehydrogenase 1 and glutathione S-transferase Yb-3 may serve as potential targets in the treatment of ANIT-induced cholestasis with melatonin.

Circulating miRNA-202-3p is a potential novel biomarker for diagnosis of type 1 gastric neuroendocrine neoplasms

Background

Currently, there are no circulating diagnostic biomarkers for gastric neuroendocrine neoplasms (g-NENs). In previous studies, we found that miRNA-202-3p is overexpressed in the tumour tissue of type 1 g-NEN. We speculated that miRNA-202-3p is also likely to be highly expressed in circulating blood.

Methods

A total of 27 patients with type 1 g-NEN and 27 age- and sex-matched control participants were enrolled in this study. The miRNA-202-3p levels in serum obtained from the participants were measured by qRT‐PCR. The expression level of miRNA-202-3p in the samples was calculated by comparison with a standard curve.

Results

The clinical characteristics of the patients were similar to those of the patient samples in previous reports. Expression of miRNA-202-3p was significantly higher in the patient group (3.84 × 10⁷ copies/nl) than in the control group (0.635 × 10⁷ copies/nl). The area under the ROC curve (AUC) was 0.878 (95% CI: 0.788–0.968), and the optimal cut-off point was approximately 1.12 × 10⁷ copies/nl. The sensitivity and specificity were 88.9% and 77.8%, respectively.

Conclusion

This study suggests that miRNA-202-3p is potentially useful as a biomarker of type 1 g-NEN; further investigation and verification should be performed in future research.

Applications and grants of National Natural Scientific Foundation of China's General Program in abnormalities and diseases of locomotor system: a ten-year review

Translational medicine is a branch of medical research that attempts to establish a more direct link between basic research and clinical practice. The improvement of clinical management cannot be separated from the progress and breakthrough made in basic biomedical research. As one of the main funding agencies for basic research in China, National Natural Scientific Foundation of China (NSFC) plays an active role in promotion of the development of basic medical research and translational medicine. General Program mainly supports scientists to carry out basic research on bottom-up based topics within the funding scope of NSFC to conduct innovative research and promote a balanced, coordinated and sustained development of all disciplines. Musculoskeletal injury and disease is a major threat to human health worldwide and has become the major cause of disability in China. In this review, we aim to further promote the clinical transformation by summarizing the trends and hotspots of basic research in this field based on the analysis of the data of General Program in abnormalities and diseases of locomotor system over the last decade, including analyses of the number of applications received and projects funded, the distribution of the keywords in applications and grants, distribution of applications and grants of General Program in the secondary application code of H06 and in the host institution.

Progress of orthopaedic research in China over the last decade

Objective

To summarize the representative scientific achievements in the past decade, and discuss the future challenges and directions for orthopaedic research in China.

Methods

In this review, we used the data provided by National Natural Science Foundation of China (NSFC) for analysis.

Results

Over the last decade, NSFC has initiated various research programs with a total funding of over 1149 million RMB to support orthopaedic exploration. Under the strong support of NSFC, great progresses have been made in basic research, talent training, platform construction and the clinical translation in the field of orthopaedics in China.

Conclusion

In general, since the establishment of the Department of Health Sciences of NSFC 10 years ago, both the amount of funding and the scale of researchers in the field of orthopaedic research have increased substantially. Despite of several shortcomings in orthopaedic research, with continuous support from NSFC both in funding and in policy, we believe that the orthopaedic research in China will surely make steady and significant progress.

The translational potential of this article

This article summarizes the representative scientific achievements in the past decade and puts forward the future challenges and directions for orthopaedic research in China.

Discovery and biological evaluation of N-(3-(7-((2-methoxy-4-(4-methylpiperazin-1-yl)phenyl)amino)-4-methyl-2-oxo-2H-pyrimido[4,5-d][1,3]oxazin-1(4H)-yl)phenyl)acrylamide as potent Bruton's tyrosine kinase inhibitors

Bruton's tyrosine kinase (BTK) is a key component of the B cell receptor (BCR) signaling pathway and plays a crucial role in B cell malignancies and autoimmune disorders; thus, it is an attractive target for the treatment of B cell related diseases. Here, we evaluated the BTK inhibitory activity of a series of pyrimido[4,5-d][1,3]oxazin-2-one derivatives. Combining this evaluation with structure-activity relationship (SAR) analysis, we found that compound 2 exhibited potent BTK kinase inhibitory activity, with an IC₅₀ of 7 nM. This derivative markedly inhibited BTK activation in TMD8 B cell lymphoma cells and thus inhibited the in vitro growth of the cells. Further studies revealed that compound 2 dose dependently arrested TMD8 cells at G₁ phase, accompanied by decreased levels of Rb, phosphorylated Rb, and cyclin D1. Moreover, following treatment with compound 2, TMD8 cells underwent apoptosis associated with PARP and caspase 3 cleavage. Interestingly, the results of the kinase activity assay on a small panel of 35 kinases showed that the kinase selectivity of compound 2 was superior to that of the first-generation inhibitor ibrutinib, suggesting that compound 2 could be a second-generation inhibitor of BTK. In conclusion, we identified a potent and highly selective BTK inhibitor worthy of further development.

Rapid and equipment-free detection of Phytophthora capsici using lateral flow strip-based recombinase polymerase amplification assay

Phytophthora capsici is an important oomycete pathogen that causes devastating diseases in various crops. Methods for the rapid detection of P. capsici are important for disease control and eradication programmes. Here, we developed an assay based on lateral flow strip-based recombinase polymerase amplification (LF-RPA) for the rapid and equipment-free detection of P. capsici. The specific primers and a probe were designed using the sequence of Ypt1, and the optimal assay conditions were 40°C for 20 min. The specificity of the assay was verified using closely related oomycetes and fungal species, and its detection limit was 10 pg of genomic DNA. In combination with a simple DNA extraction method, the LF-RPA assay enabled detection of P. capsici in diseased pepper samples without specialized equipment within 30 min. Consequently, the LF-RPA assay developed in this study enables rapid and equipment-free detection of P. capsici and has potential for further development as a diagnostic kit for application in the field or in resource-limited laboratories. SIGNIFICANCE AND IMPACT OF THE STUDY: We developed a novel assay based on lateral flow strip-based recombinase polymerase amplification (LF-RPA) for the rapid and equipment-free detection of Phytophthora capsici. In combination with a simple DNA extraction method, the LF-RPA assay detected P. capsici in field samples without specialized equipment within 30 min. The assay has potential for further development as a diagnostic kit for application in the field or in resource-limited laboratories.

Decreased PKG transcription mediated by PI3K/Akt/FoxO1 pathway is involved in the development of nitroglycerin tolerance

Phosphoinositide 3-kinase (PI3K)/Akt plays a pivotal role in the vascular response. The present study is to determine whether PI3K/Akt pathway in vascular smooth muscle cells is involved in nitroglycerin (NTG) tolerance and the underlying mechanism. Nitrate tolerance of porcine coronary arteries in vitro was induced by incubation of NTG (10^-5 M) for 24 h. Nitrate tolerance in vivo was obtained by subcutaneous injection of mice with NTG (20 mg kg^-1, tid, 3 days) and the aortas were used. Protein levels of total and phosphorylated Akt, forkhead box protein O1 (FoxO1), and cGMP-dependent protein kinase (PKG) were determined by western blot analysis. Isometric vessel tension was recorded by organ chamber technique. PKG mRNA was determined by real-time PCR. The cellular translocation of FoxO1 was observed by immunofluorescence. Reactive oxygen species (ROS) level was measured by DHE staining. The vascular relaxation to NTG was significantly inhibited in in vivo and in vitro NTG tolerant arteries. Meanwhile, the protein level of phosphorylated Akt at Ser473 was increased in the tolerant arteries. The attenuated relaxation and the augmented Akt-p were ameliorated by LY294002, a specific inhibitor of PI3K. The protein and mRNA expression of PKG were significantly down-regulated in NTG tolerant arteries, which were reversed by LY294002. The level of phosphorylated FoxO1 at Ser256 and its translocation from the nucleus to the cytosol were both increased in NTG tolerance and were also inhibited by LY294002. ROS production was significantly increased in NTG tolerant arteries, which was not be affected by LY294002 but inhibited by N-acetyl-L-cysteine. In conclusion, the present study suggests that PI3K/Akt in vascular smooth muscle is involved in the development of NTG tolerance via inhibiting PKG transcription and the effect is mediated by FoxO1.

Discovery and biological evaluation of N5-substituted 6,7-dioxo-6,7-dihydropteridine derivatives as potent Bruton's tyrosine kinase inhibitors

Bruton's tyrosine kinase (BTK) plays a critical role in B cell receptor (BCR)-mediated signaling pathways responsible for the development and function of B cells, which makes it an attractive target for the treatment of many types of B-cell malignancies. Herein, a series of N5-substituted 6,7-dioxo-6,7-dihydropteridine-based, irreversible BTK inhibitors were reported with IC₅₀ values ranging from 1.9 to 236.6 nM in the enzymatic inhibition assay. Compounds 6 and 7 significantly inhibited the proliferation of Ramos cells which overexpress the BTK enzyme, as well as the autophosphorylation of BTK at Tyr223 and the activation of its downstream signaling molecule PLCγ2. Overall, this series of compounds could provide a promising starting point for further development of potent BTK inhibitors for B-cell malignancy treatment.

Hsa-miR-202-3p, up-regulated in type 1 gastric neuroendocrine neoplasms, may target DUSP1

AIM

To detect abnormal microRNA (miRNA) expression in type 1 gastric neuroendocrine neoplasms (g-NENs) and find potential target genes.

METHODS

Tumour tissues from patients with type 1 g-NENs were used as experimental samples, and gastric mucosal tissues from the same patients obtained during gastroscopy review after several months were used as control samples. miRNA expression was examined with Agilent human miRNA chips and validated via RT-PCR. Three types of target gene prediction software (TargetScan, PITA, and microRNAorg) were used to predict potential target genes of the differentially expressed miRNAs, and a dual-luciferase reporter assay system was used for verification.

RESULTS

Six miRNAs were significantly upregulated or downregulated in the tumours compared to the control samples. Among them, miR-202-3p was extraordinarily upregulated. RT-PCR of seven sample sets confirmed that miR-202-3p was upregulated in tumour tissues. In total, 215 target genes were predicted to be associated with miR-202-3p. Among them, dual-specificity phosphatase 1 (DUSP1) was reported to be closely related to tumour occurrence and development. The dual-luciferase reporter assay showed that miR-202-3p directly regulated DUSP1 in 293T cells.

CONCLUSION

miR-202-3p is upregulated in type 1 g-NEN lesions and might play important roles in the pathogenesis of type 1 g-NENs by targeting DUSP1.

Porphyrin photosensitizers in photodynamic therapy and its applications

In 1841, the extraction of hematoporphyrin from dried blood by removing iron marked the birth of the photosensitizer. The last twenty years has witnessed extensive research in the application of photodynamic therapy (PDT) in tumor-bearing (or other diseases) animal models and patients. The period has seen development of photosensitizers from the first to the third generation, and their evolution from simple to more complex entities. This review focuses on porphyrin photosensitizers and their effect on tumors, mediated via several pathways involved in cell necrosis, apoptosis or autophagic cell death, and the preventive and therapeutic application of PDT against atherosclerosis.

[Analysis of the application and funding projects of National Natural Science Foundation of China in the field of burns and plastic surgery from 2010 to 2016]

We analyzed the data of application and funding projects of the National Natural Science Foundation of China (NSFC) during 2010-2016 in the field of burns and plastic surgery and summarized the NSFC funding pattern, the research hotspots, and weaknesses in this field. The NSFC has funded 460 projects in the field of burns and plastic surgery, with total funding of RMB 227.96 million. The scientific issues involved in the funding projects include orthotherapy against malformations, wound repair, basic research of burns, skin grafting, scars prevention, and regeneration of hair follicle and sweat glands. The research techniques involved in the funding projects are diversified. NSFC plays an important role in the scientific research and talents training in the field of burns and plastic surgery.

Upconversion nanoparticle-mediated photodynamic therapy induces autophagy and cholesterol efflux of macrophage-derived foam cells via ROS generation

Macrophage-derived foam cells are a major component of atherosclerotic plaques and have an important role in the progression of atherosclerotic plaques, thus posing a great threat to human health. Photodynamic therapy (PDT) has emerged as a therapeutic strategy for atherosclerosis. Here, we investigated the effect of PDT mediated by upconversion fluorescent nanoparticles encapsulating chlorin e6 (UCNPs-Ce6) on the cholesterol efflux of THP-1 macrophage-derived foam cells and explored the possible mechanism of this effect. First, we found that PDT notably enhanced the cholesterol efflux and the induction of autophagy in both THP-1 and peritoneal macrophage-derived foam cells. The autophagy inhibitor 3-methyladenine and an ATG5 siRNA significantly attenuated PDT-induced autophagy, which subsequently suppressed the ABCA1-mediated cholesterol efflux. Furthermore, the reactive oxygen species (ROS) produced by PDT were responsible for the induction of autophagy, which could be blocked by the ROS inhibitor N-acetyl cysteine (NAC). NAC also reversed the PDT-induced suppression of p-mTOR and p-Akt. Therefore, our findings demonstrate that PDT promotes cholesterol efflux by inducing autophagy, and the autophagy was mediated in part through the ROS/PI3K/Akt/mTOR signaling pathway in THP-1 and peritoneal macrophage-derived foam cells.

Homocysteine ameliorates the endothelium-independent hypoxic vasoconstriction via the suppression of phosphatidylinositol 3-kinase/Akt pathway in porcine coronary arteries

OBJECTIVE

Endothelium-independent coronary vasoconstriction induced by continuous hypoxia contributes to the development of ischemic heart diseases. Acute elevation of homocysteine (Hcy) has a potent of vasodilation. The present study aims to investigate the role of Hcy in endothelium-independent hypoxic coronary vasoconstriction and its underlying mechanisms.

METHODS AND RESULTS

Vessel tension of isolated porcine coronary arteries was measured by organ chamber study and the protein expression were detected by western blot. A sustained contraction of porcine coronary artery was induced when exposed to prolonged hypoxia for more than 15 min, which was significantly reduced by Hcy in a dose-dependent manner but not affected by cysteine or N-acetyl-l-cysteine. Phosphorylated myosin light chain (MLC-p) at Ser19 was decreased when exposure to hypoxia for 15 min, and could be reversed by prolonged hypoxia for 30 and 60 min. The recovery of MLC-p at Ser19 by hypoxia for more than 30 min could be abolished by Hcy. The protein levels of phosphorylated Akt at Ser473 and phosphorylated P85 at Tyr508 were decreased by Hcy in normoxia, and were also reduced exposure to hypoxia for 15 min and then augmented by prolonged hypoxia for more than 30 min, which could be prevented by Hcy. The protein level of P110α was not affected by Hcy or prolonged hypoxia.

CONCLUSIONS

This study demonstrates that Hcy can ameliorate the endothelium-independent hypoxic coronary vasoconstriction, in which the inhibition of PI3K/Akt signaling pathway may be involved.

Gastric neuroendocrine tumor (NET): report of one case

In this article we reported a female patient with type 1 gastric neuroendocrine tumor (NET). Gastroscopy showed the presence of multiple polyp-like lesions sized 0.2-1.5 cm in the fundus and body of stomach. The main clinical manifestations were belching and fullness after a meal. She had a history of autoimmune atrophic gastritis and laboratory tests showed increased serum gastrin and acid deficiency, which met the diagnostic criteria of type 1 gastric NET. Treatments included endoscopic resection, sandostatin, and traditional Chinese herbs, and no relapse was noted during follow-up visits. The patient also had rectal NET. By analyzing this case, we tried to explore the diagnostic algorithm and clinical typing of type 1 gastric NET; meanwhile, along with literature review, we described the relapse rate of this disease and the value of regular follow-up (every 6-12 months). Finally, we analyzed the value of somatostatin analogue (SSA) in treating multiple type 1 gastric NET and in this case we demonstrated that SSA was effective in dissolving NET.

cIMP synthesized by sGC as a mediator of hypoxic contraction of coronary arteries

cGMP is considered the only mediator synthesized by soluble guanylyl cyclase (sGC) in response to nitric oxide (NO). However, purified sGC can synthesize several other cyclic nucleotides, including inosine 3',5'-cyclic monophosphate (cIMP). The present study was designed to determine the role of cIMP in hypoxic contractions of isolated porcine coronary arteries. Vascular responses were examined by measuring isometric tension. Cyclic nucleotides were assayed by HPLC tandem mass spectroscopy. Rho kinase (ROCK) activity was determined by measuring the phosphorylation of myosin phosphatase target subunit 1 using Western blot analysis and an ELISA kit. The level of cIMP, but not that of cGMP, was elevated by hypoxia in arteries with, but not in those without, endothelium [except if treated with diethylenetriamine (DETA) NONOate]; the increases in cIMP were inhibited by the sGC inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ). Hypoxia (Po2: 25-30 mmHg) augmented contractions of arteries with and without endothelium if treated with DETA NONOate; these hypoxic contractions were blocked by ODQ. In arteries without endothelium, hypoxic augmentation of contraction was also obtained with exogenous cIMP. In arteries with endothelium, hypoxic augmentation of contraction was further enhanced by inosine 5'-triphosphate, the precursor for cIMP. The augmentation of contraction caused by hypoxia or cIMP was accompanied by increased phosphorylation of myosin phosphatase target subunit 1 at Thr(853), which was prevented by the ROCK inhibitor Y-27632. ROCK activity in the supernatant of isolated arteries was stimulated by cIMP in a concentration-dependent fashion. These results demonstrate that cIMP synthesized by sGC is the likely mediator of hypoxic augmentation of coronary vasoconstriction, in part by activating ROCK.

Endothelium-independent hypoxic contraction of porcine coronary arteries may be mediated by activation of phosphoinositide 3-kinase/Akt pathway

Phosphoinositide 3-kinase (PI3K)/Akt signaling pathway plays an essential role in the regulation of vascular tone. The present study aimed to determine its role in hypoxic coronary vasoconstriction. Isometric tension of isolated porcine coronary arteries was measured with organ chamber technique; the protein levels of phosphorylated and total MLC were examined by Western blotting; the activities of PI3K and Rho kinase were determined by the phosphorylation of their respective target protein Akt and MTPT1. Acute hypoxia induced a rapid contraction followed by a short-term relaxation and then a sustained contraction in porcine coronary arteries. The rapid but not the sustained contraction was abolished by endothelium removal. The sustained contraction was attenuated by inhibitors of PI3K (LY294002) and Akt (Akt-I). The attenuation effect caused by LY294002 was not affected by nifedipine, but was abolished by Y27632, an inhibitor of Rho kinase. The sustained hypoxic contraction was associated with altered phosphorylation of MLC and Akt, which was inhibited by LY294002. The sustained hypoxic contraction was also accompanied with increased phosphorylation of MYPT1, which was inhibited by LY294002 and Y27632. This study demonstrates that sustained hypoxia causes porcine coronary artery to contract in an endothelium-independent manner. An increased PI3K/Akt/Rho kinase signaling may be involved.

Preservation of nitric oxide-induced relaxation of porcine coronary artery: roles of the dimers of soluble guanylyl cyclase, phosphodiesterase type 5, and cGMP-dependent protein kinase

Soluble guanylyl cyclase (sGC), phosphodiesterase type 5 (PDE5), and guanosine 3',5'-cyclic monophosphate (cGMP)-dependent protein kinase (PKG) are all dimeric. The present study was to determine the role of their dimeric status in nitric oxide-induced vasodilatation. In isolated porcine coronary arteries, after 20 h incubation with serum-free medium, serum-containing medium, or phosphate-buffered saline solution, the protein levels of the dimers of sGC, PDE5, and PKG were diminished while the monomer levels remained unchanged, associated with reduced cGMP elevation in response to DETA NONOate and decreased PDE5 activity; the activity of PKG was not significantly altered. DETA NONOate caused a greater relaxation in arteries incubated for 20 vs. 2 h. The relaxant response was largely abolished by 1H-[1, 2, 4]oxadiazolo[4,3-a]quinoxalin-1-one, an sGC inhibitor. Zaprinast, a PDE5 inhibitor, had no effect on relaxation caused by DETA NONOate of arteries incubated for 20 h but augmented the response incubated for 2 h. A greater relaxation to 8-bromo-guanosine 3'5'-cyclic monophosphate occurred in arteries incubated for 20 than for 2 h. The protein level of the dimers but not monomers of PDE5 was reduced by dithiothreitol and unaffected by hydrogen peroxide, accompanied with decreased PDE5 activity and reduced response to DETA NONOate. These results demonstrate that the dimeric but not monomeric status of sGC and PDE5 of coronary arteries are closely related to their activities. The preserved vasodilator response after 20 h incubation may result in part from a synchronous reduction of the dimer levels of sGC and PDE5 as well as an augmented response to cGMP.

Sulfhydryl-dependent dimerization of soluble guanylyl cyclase modulates the relaxation of porcine pulmonary arteries to nitric oxide

The dimeric status of nitric oxide (NO)-sensitive soluble guanylyl cyclase (sGC) is obligatory for its catalyzing activity to synthesis the second messenger cyclic guanosine monophosphate (cGMP), which leads to vasodilatation. The present study was conducted to determine whether or not the dimerization of sGC is modulated by thiol-reducing agents and its influences on relaxation of pulmonary arteries caused by NO. The dimers and monomers of sGC and cGMP-dependent protein kinase (PKG) were analyzed by Western blotting. The intracellular cGMP content was measured by enzyme-linked immunosorbent assay. Relaxations of isolated porcine pulmonary arteries were determined by organ chamber technique. Protein levels of sGC dimers were decreased by thiol reductants dithiothreitol (DTT), reduced L-glutathione, L-cysteine, and tris(2-carboxyethyl)phosphine (TCEP), associated with decreased cGMP elevation, attenuated relaxations to NO. DTT at concentrations that affected sGC dimerization and activity showed no effect on PKG dimerization nor relaxation to 8-Br-cGMP. Hypoxia decreased the dimerization and activity of sGC of the arteries. The suppression of DTT and TCEP on sGC dimerization and activity was augmented by hypoxia. In the presence of DTT and TCEP, relaxations of porcine pulmonary artery caused by NO were significantly less under hypoxia compared with those under normoxia. These results suggest that the dimerization and activity of sGC along with NO-induced vasodilatation can be modulated in a thiol-dependent manner. Such a mechanism may be involved in the diminished response of pulmonary arteries to NO under hypoxia.

Inactivation of the E-prostanoid 3 receptor attenuates the angiotensin II pressor response via decreasing arterial contractility

OBJECTIVE

The present studies aimed at elucidating the role of prostaglandin E(2) receptor subtype 3 (E-prostanoid [EP] 3) in regulating blood pressure.

METHODS AND RESULTS

Mice bearing a genetic disruption of the EP3 gene (EP(3)(-/-)) exhibited reduced baseline mean arterial pressure monitored by both tail-cuff and carotid arterial catheterization. The pressor responses induced by EP3 agonists M&B28767 and sulprostone were markedly attenuated in EP3(-/-) mice, whereas the reduction of blood pressure induced by prostaglandin E(2) was comparable in both genotypes. Vasopressor effect of acute or chronic infusion of angiotensin II (Ang II) was attenuated in EP3(-/-) mice. Ang II-induced vasoconstriction in mesenteric arteries decreased in EP3(-/-) group. In mesenteric arteries from wild-type mice, Ang II-induced vasoconstriction was inhibited by EP3 selective antagonist DG-041 or L798106. The expression of Arhgef-1 is attenuated in EP3 deficient mesenteric arteries. EP3 antagonist DG-041 diminished Ang II-induced phosphorylation of myosin light chain 20 and myosin phosphatase target subunit 1 in isolated mesenteric arteries. Furthermore, in vascular smooth muscle cells, Ang II-induced intracellular Ca(2+) increase was potentiated by EP3 agonist sulprostone but inhibited by DG-041.

CONCLUSIONS

Activation of the EP3 receptor raises baseline blood pressure and contributes to Ang II-dependent hypertension at least partially via enhancing Ca(2+) sensitivity and intracellular calcium concentration in vascular smooth muscle cells. Selective targeting of the EP3 receptor may represent a potential therapeutic target for the treatment of hypertension.

Hypoxia induces downregulation of soluble guanylyl cyclase β1 by miR-34c-5p

Soluble guanylyl cyclase (sGC) is the principal receptor for nitric oxide (NO) and crucial for the control of various physiological functions. The β1 subunit of sGC is obligatory for the biological stability and activity of the sGC heterodimer. MicroRNAs (miRNAs) are important regulators of gene expression and exert great influences on diverse biological activities. The aim of the present study was to determine whether or not the expression of sGCβ1 is specifically regulated by miRNAs. We report that miR-34c-5p directly targets sGCβ1 under hypoxia. Bioinformatics analysis of the sGCβ1 3'-untranslated region (3'-UTR) revealed a putative binding site for miR-34b-5p and miR-34c-5p, but only miR-34c-5p inhibited luciferase activity through interaction with sGCβ1 3'-UTR in HEK293T cells. Site-directed mutagenesis of the putative miR-34c-5p binding site abolished the negative regulation of luciferase expression. Overexpression of miR-34c-5p repressed the expression of sGCβ1 in stable cell lines, which was reversed by miR-34c-5p-specific sponge. Inoculation of mouse lung tissues in vitro with lentivirus bearing miR-34c-5p significantly decreased both the expression of sGCβ1 and NO-stimulated sGC activity, which was also rescued by miR-34c-5p-specific sponge. Furthermore, we identified the putative Sp1-binding site in the promoter region of miR-34c-5p. Luciferase reporter constructs revealed that Sp1 directly binds to the wild-type promoter of miR-34c-5p, which was confirmed by chromatin immunoprecipitation. In summary, these findings reveal that miR-34c-5p directly regulates sGCβ1 expression, and they identify the key transcription factor Sp1 that governs miR-34c-5p expression during hypoxia.

Hydrogen peroxide enhances vasodilatation by increasing dimerization of cGMP-dependent protein kinase type Iα

BACKGROUND

cGMP-dependent protein kinase type I (PKG I) plays a key role in vasodilatation caused by cGMP-elevating agents. It is a homodimer in mammalian cells, existing as 2 isoforms, Iα and Iβ. The aim of the present study was both to determine whether PKG I dimerization and activity are modulated by hydrogen peroxide (H(2)O(2)) and its influence on vasodilatation.

METHODS AND RESULTS

The dimers and monomers of total PKG I and PKG Iβ were analyzed by Western blotting. PKG I activity was assayed by measuring the incorporation of (32)P into BPDEtide. Changes in vessels tension were determined by organ chamber technique. In isolated porcine coronary arteries, H(2)O(2) increased the dimers of total PKG I in a concentration-dependent manner, but had no effect on dimerization of PKG Iβ. The dimerization of PKG I caused by H(2)O(2) was prevented by catalase but not by deferoxamine and tiron. H(2)O(2) promoted the translocation of PKG I from cytoplasm to membrane. H(2)O(2) enhanced the activity of PKG I and relaxations of porcine coronary arteries to the nitric oxide donor and 8-Br-cGMP. Inhibition of catalase under in vivo conditions significantly decreased rat mean arterial pressure, which was associated with increased dimerization of PKG I.

CONCLUSIONS

The present study suggests that H(2)O(2) may enhance the activity of PKG Iα-and PKG I-dependent vasodilatation via increased dimerization of the enzyme.

Inhibition of phosphoinositide 3-kinase potentiates relaxation of porcine coronary arteries induced by nitroglycerin by decreasing phosphodiesterase type 5 activity

BACKGROUND

Vessel tension can be modulated by phosphoinositide 3-kinase (PI3K) acting on l-type calcium channel, rho kinase and phosphodiesterase (PDE) type 3 in smooth muscle cells. Inhibition of PI3K could increase the relaxation of porcine coronary arteries to nitroglycerin independent of this pathway, and the aim of the present study was therefore to determine the underlying mechanisms.

METHODS AND RESULTS

Isolated porcine coronary arteries were dissected from the heart and cut into rings in ice-cold modified Krebs-Ringer bicarbonate buffer. The response of these vessels was studied by using the organ chamber technique; the content of cyclic guanosine monophosphate (cGMP) was determined by using enzyme-linked immunosorbent assay kit; and PI3K and Akt activity were determined by measuring the phosphorylation level of their downstream signaling molecule on Western blot. Inhibition of PI3K with 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002) potentiated the relaxation of porcine coronary arteries to nitroglycerin and nitric oxide (NO), but not to 8-bromo-guanosine 3'5'-cyclic monophosphate, isoproterenol or (R)-(+)-trans-4-(1-Aminoethyl)-N-(4-Pyridyl)cyclohexanecarboxamide dihydrochloride monohydrate (Y27632). Increased relaxation induced by LY294002 was eliminated by Akt1/2 kinase inhibitor (Akt-I: 1,3-dihydro-1-(1-((4-(6-phenyl-1H-imidazo(4,5-g)quinoxalin-7-yl)phenyl)methyl)-4-piperidinyl)-2H-benzimidazol-2-one trifluoroacetate salt hydrate) or zaprinast, but was not affected by 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, nifedipine or milrinone. Inhibition of Akt caused similar effects as LY294002. Incubation with LY294002 or Akt-I decreased the activity of PI3K and Akt but augmented the elevation of cGMP caused by NO. Enhanced cGMP elevation induced by LY294002 or Akt-I was also eliminated by zaprinast.

CONCLUSIONS

PI3K-Akt signaling may affect vascular tone through a stimulatory effect on PDE type 5.

Heterogeneity in relaxation of different sized porcine coronary arteries to nitrovasodilators: role of PKG and MYPT1

The present study was to determine the role of the type I isoform of cGMP-dependent protein kinase (PKG I) and its downstream effector myosin phosphatase target subunit 1 (MYPT1) in the responses of different sized coronary arteries to nitrovasodilators. Relaxations of isolated porcine coronary arteries were determined by isometric tension recording technique. Protein levels of PKG I and its effectors were analyzed by Western blotting. The activities of PKG I and MYPT1 were studied by analyzing phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and MYPT1, respectively. Nitroglycerin, DETA NONOate, and 8-Br-cGMP caused greater relaxations in large than in small coronary arteries. Relaxations were attenuated to a greater extent by Rp-8-Br-PET-cGMPS (a PKG inhibitor) in large vs. small arteries. The expressions of PKG I and MYPT1 in large arteries were more abundant than in small arteries. DETA NONOate stimulated phosphorylation of VASP at Ser239 and inhibited phosphorylation of MYPT1 at Thr853 to a greater extent in large than in small arteries. A suppressed phosphorylation of MYPT1 at Thr853 was caused by 8-Br-cGMP in large but not small arteries, which was inhibited by Rp-8-Br-PET-cGMPS. These results suggest that the greater responsiveness of large coronary arteries to nitrovasodilators result in part from greater activities of PKG I and MYPT1. Dysfunction in nitric oxide signaling is implicated in the vulnerability of large coronary arteries to certain disorders such as atherosclerosis and spasm. Augmentation of PKG I-MYPT1 signaling may be of therapeutic benefit for combating these events.

Role of sulfhydryl-dependent dimerization of soluble guanylyl cyclase in relaxation of porcine coronary artery to nitric oxide

AIMS

Soluble guanylyl cyclase (sGC) is a heterodimer. The dimerization of the enzyme is obligatory for its function in mediating actions caused by agents that elevate cyclic guanosine monophosphate (cGMP). The present study aimed to determine whether sGC dimerization is modulated by thiol-reducing agents and whether its dimerization influences relaxations in response to nitric oxide (NO).

METHODS AND RESULTS

The dimers and monomers of sGC and cGMP-dependent protein kinase (PKG) were analysed by western blotting. The intracellular cGMP content was measured by enzyme-linked immunosorbent assay. Changes in isometric tension were determined in organ chambers. In isolated porcine coronary arteries, the protein levels of sGC dimer were decreased by the thiol reductants dithiothreitol, l-cysteine, reduced l-glutathione and tris(2-carboxyethyl) phosphine. The effect was associated with reduced cGMP elevation and attenuated relaxations in response to nitric oxide donors. The dimerization of sGC and activation of the enzyme were also decreased by dihydrolipoic acid, an endogenous thiol antioxidant. Dithiothreitol at concentrations markedly affecting the dimerization of sGC had no significant effect on the dimerization of PKG or relaxation in response to 8-Br-cGMP. Relaxation of the coronary artery in response to a NO donor was potentiated by hypoxia when sGC was partly inhibited, coincident with an increase in sGC dimer and enhanced cGMP production. These effects were prevented by dithiothreitol and tris(2-carboxyethyl) phosphine.

CONCLUSION

These results demonstrate that the dimerization of sGC is exquisitely sensitive to thiol reductants compared with that of PKG, which may provide a novel mechanism for thiol-dependent modulation of NO-mediated vasodilatation in conditions such as hypoxia.

Increased degradation of MYPT1 contributes to the development of tolerance to nitric oxide in porcine pulmonary artery

Myosin phosphatase target subunit 1 (MYPT1) is the regulatory subunit of myosin light chain phosphatase (MLCP). It plays a critical role in vasodilatation induced by cGMP-elevating agents such as nitric oxide (NO). The present study was performed to determine the role of MYPT1 in the development of tolerance of the pulmonary artery to NO. Incubation of isolated porcine pulmonary arteries for 24 or 48 h with DETA NONOate (DETA NO) significantly reduced protein levels of MYPT1 and the leucine zipper-positive (LZ+) isoform of MYPT1 but not that of PP1cdelta. The extent of reduction in total MYPT1 protein level was comparable to that of MYPT1 (LZ+). The decrease in MYPT1 protein caused by 48-h DETA NO incubation was prevented by ODQ, an inhibitor of guanylyl cyclase, and by inhibitors of proteasomes (MG-132 and lactacystin) but was not affected by the inhibitor of protein synthesis, cycloheximide. A reduction in MYPT1 protein was also obtained with 8-bromo-cGMP, but this was prevented by Rp-8-bromo-PET-cGMP [inhibitor of cGMP-dependent protein kinase (PKG)]. Incubation for 48 h with DETA NO also reduced dephosphorylation of myosin light chain and relaxation of the artery in response to DETA NO, which was prevented by MG-132. These results suggest that the reduction in MYPT1 protein contributes to the development of tolerance of pulmonary arteries to NO. This may result from increased degradation of MYPT1 after prolonged PKG activation.

Degradation of leucine zipper-positive isoform of MYPT1 may contribute to development of nitrate tolerance

AIMS

A depressed cGMP-dependent protein kinase (PKG) activity is implicated in nitrate tolerance. The present study determines whether the leucine zipper-positive (LZ+) isoform of myosin phosphatase target subunit 1 (MYPT1), a key target protein for PKG actions, is involved in the development of nitrate tolerance.

METHODS AND RESULTS

Nitrate tolerance in in vitro preparations was obtained by a 24 h incubation with nitroglycerin (NTG). Nitrate tolerance in in vivo preparations was obtained by subcutaneous injection of mice with NTG, and the aortas were used. Protein levels of total MYPT1, MYPT1 (LZ+), PP1Cdelta, myosin light chain (MLC), and phosphorylated MLC were determined by Western blot analysis. Isometric vessel tension was determined by an organ chamber technique. Protein levels of MYPT1 (LZ+), but not of PP1Cdelta, were significantly reduced in in vitro and in vivo nitrate-tolerant arteries. The decrease in the MYPT1 (LZ+) protein level of coronary artery was also induced by a nitric oxide donor and a cGMP analogue, which was prevented by the inhibitors of soluble guanylyl cyclase and PKG. The decrease in MYPT1 (LZ+) protein levels was not affected by the inhibitor of protein synthesis, but was prevented by the inhibitors of proteasomes. The diminished inhibition of dephosphorylation of MLC as well as the attenuated relaxation of porcine coronary artery and mouse aorta to NTG was improved by proteasome inhibitors.

CONCLUSION

This study demonstrates that a reduction in the protein level of MYPT1 (LZ+) is involved in nitrate tolerance. This may result in part from a proteasome-dependent degradation of MYPT1 (LZ+).

Role of cGMP-dependent protein kinase in development of tolerance to nitroglycerine in porcine coronary arteries

BACKGROUND AND PURPOSE

The cGMP-dependent protein kinase (PKG) is a key enzyme for nitrovasodilator-induced vasodilation. The present study was to determine its role in nitrate tolerance.

EXPERIMENTAL APPROACH

isolated porcine coronary arteries were incubated for 24 h with nitroglycerin (NTG) and their relaxant responses were determined. PKG activity was assayed by measuring the incorporation of (32)P into BPDEtide. PKG protein was determined by Western blotting and PKG mRNA by real-time PCR.

KEY RESULTS

A 24 h incubation with NTG attenuated relaxation of coronary arteries to NTG, which was associated with decreased PKG activity. The nitrate tolerance induced with NTG at 10(-7) M was affected by a scavenger of reactive oxygen species and the tolerance induced with NTG at 10(-6) and 10(-5) M showed cross-tolerance to DETA NONOate and 8-Br-cGMP (a cell permeable cGMP analogue). PKG protein and mRNA were down-regulated by a 24 h incubation with NTG at 10(-5) M but not at 10(-7) M. Acute exposure to exogenous superoxide inhibited PKG activity stimulated by NTG at 10(-7) M but not at 10(-5) M. Superoxide had no effect on PKG activity stimulated with exogenous cGMP.

CONCLUSIONS AND IMPLICATIONS

Nitrate tolerance induced by NTG at low concentrations may result from an increased production of reactive oxygen species acting on sites upstream of PKG. The tolerance induced by NTG at higher concentrations may be in part due to suppression of PKG expression resulting from sustained activation of the enzyme. These distinct mechanisms of nitrate tolerance may be of clinical significance.

Antihypertensive effects of selective prostaglandin E2 receptor subtype 1 targeting

Clinical use of prostaglandin synthase-inhibiting NSAIDs is associated with the development of hypertension; however, the cardiovascular effects of antagonists for individual prostaglandin receptors remain uncharacterized. The present studies were aimed at elucidating the role of prostaglandin E2 (PGE2) E-prostanoid receptor subtype 1 (EP1) in regulating blood pressure. Oral administration of the EP1 receptor antagonist SC51322 reduced blood pressure in spontaneously hypertensive rats. To define whether this antihypertensive effect was caused by EP1 receptor inhibition, an EP1-null mouse was generated using a "hit-and-run" strategy that disrupted the gene encoding EP1 but spared expression of protein kinase N (PKN) encoded at the EP1 locus on the antiparallel DNA strand. Selective genetic disruption of the EP1 receptor blunted the acute pressor response to Ang II and reduced chronic Ang II-driven hypertension. SC51322 blunted the constricting effect of Ang II on in vitro-perfused preglomerular renal arterioles and mesenteric arteriolar rings. Similarly, the pressor response to EP1-selective agonists sulprostone and 17-phenyltrinor PGE2 were blunted by SC51322 and in EP1-null mice. These data support the possibility of targeting the EP1 receptor for antihypertensive therapy.

Protein kinase G regulates the basal tension and plays a major role in nitrovasodilator-induced relaxation of porcine coronary veins

BACKGROUND AND PURPOSE

Coronary venous activity is modulated by endogenous and exogenous nitrovasodilators. The present study was to determine the role of protein kinase G (PKG) in the regulation of the basal tension and nitrovasodilator-induced relaxation of coronary veins.

EXPERIMENTAL APPROACH

Effects of a PKG inhibitor on the basal tension and responses induced by nitroglycerin, DETA NONOate, and 8-Br-cGMP in isolated porcine coronary veins were determined. Cyclic cGMP was measured with radioimmunoassay. PKG activity was determined by measuring the incorporation of 32P from gamma-32P-ATP into the specific substrate BPDEtide.

KEY RESULTS

Rp-8-Br-PET-cGMPS, a specific PKG inhibitor, increased the basal tension of porcine coronary veins and decreased PKG activity. The increase in tension was 38% of that caused by nitro-L-arginine. Relaxation of the veins induced by nitroglycerin and DETA NONOate was accompanied with increases in cGMP content and PKG activity. These effects were largely eliminated by inhibiting soluble guanylyl cyclase with ODQ. The increase in PKG activity induced by the nitrovasodilators was abolished by Rp-8-Br-PET-cGMPS. The relaxation caused by these dilators and by 8-Br-cGMP at their EC50 was attenuated by the PKG inhibitor by 51-66%.

CONCLUSIONS AND IMPLICATIONS

These results suggest that PKG is critically involved in nitric oxide-mediated regulation of the basal tension in porcine coronary veins and that it plays a primary role in relaxation induced by nitrovasodilators. Since nitric oxide plays a key role in modulating coronary venous activity, augmentation of PKG may be a therapeutic target for improving coronary blood flow.