Leucine zipper protein 1 attenuates pressure overload-induced cardiac hypertrophy through inhibiting Stat3 signaling.

INTRODUCTION: Cardiac hypertrophy is an important contributor of heart failure, and the mechanisms remain unclear. Leucine zipper protein 1 (LUZP1) is essential for the development and function of cardiovascular system; however, its role in cardiac hypertrophy is elusive. OBJECTIVES: This study aims to investigate the molecular basis of LUZP1 in cardiac hypertrophy and to provide a rational therapeutic approach. METHODS: Cardiac-specific Luzp1 knockout (cKO) and transgenic mice were established, and transverse aortic constriction (TAC) was used to induce pressure overload-induced cardiac hypertrophy. The possible molecular basis of LUZP1 in regulating cardiac hypertrophy was determined by transcriptome analysis. Neonatal rat cardiomyocytes were cultured to elucidate the role and mechanism of LUZP1 in vitro. RESULTS: LUZP1 expression was progressively increased in hypertrophic hearts after TAC surgery. Gain- and loss-of-function methods revealed that cardiac-specific LUZP1 deficiency aggravated, while cardiac-specific LUZP1 overexpression attenuated pressure overload-elicited hypertrophic growth and cardiac dysfunction in vivo and in vitro. Mechanistically, the transcriptome data identified Stat3 pathway as a key downstream target of LUZP1 in regulating pathological cardiac hypertrophy. Cardiac-specific Stat3 deletion abolished the pro-hypertrophic role in LUZP1 cKO mice after TAC surgery. Further findings suggested that LUZP1 elevated the expression of Src homology region 2 domain-containing phosphatase 1 (SHP1) to inactivate Stat3 pathway, and SHP1 silence blocked the anti-hypertrophic effects of LUZP1 in vivo and in vitro. CONCLUSION: We demonstrate that LUZP1 attenuates pressure overload-induced cardiac hypertrophy through inhibiting Stat3 signaling, and targeting LUZP1 may develop novel approaches to treat pathological cardiac hypertrophy.

Lipoprotein(a) and Benefit of PCSK9 Inhibition in Emergency Complex Higher-risk and Indicated Patients.

OBJECTIVE: There is a large population of patients classified as complex higher-risk and indicated patients (CHIPs) in China with a poor prognosis. The treatment of these patients is complex and challenging, especially when acute cardiac events occur, such as acute coronary syndrome (ACS) or heart failure. Pharmacotherapy and some mechanical circulatory support (MCS) therapeutic devices can provide stable hemodynamic support for CHIPs-percutaneous coronary intervention (PCI). LDL-C is an important pathogenic factor in atherosclerosis, and the target of blood lipid control. Recent studies have revealed that lipoprotein(a) [Lp(a)], which is formed when a covalent bond between apolipoprotein(a) and apolipoprotein B-100 is made, produces an LDL-like particle. This particle is an independent risk factor for the development of atherosclerosis, and is closely correlated to stent thrombosis and restenosis. Furthermore, this requires active intervention. PCSK9 inhibitors have been used in lipid-lowering treatment, and preventing atherosclerosis. The present study explores the efficacy of PCSK9 inhibitors in CHIPs-ACS, and the association between the change in Lp(a) and survival after 2 years of follow-up. METHODS: The present real-world, prospective control study enrolled 321 CHIPs-ACS who underwent emergency PCI from August 2019 to November 2020, and these patients were followed up for 2 years. These patients were divided into two groups: PCSK9 group (n=161) given the combined PCSK9 inhibitor (140 mg of evolocumab every 2 weeks) and statins-based therapy, and SOC group (n=160) treated with statin-based lipid-lowering therapy alone. Then, the change in lipid index was measured, and the cardiovascular (CV) event recurrence rate was evaluated after one month and 2 years. Afterwards, the contribution of serum lipid parameters, especially the Lp(a) alteration, in patients with earlier initiation of the PCSK9 inhibitor to the CV outcome was analyzed. RESULTS: The LDL-C level was significantly reduced in both groups: 52.3% in the PCSK9 group and 32.3% (P<0.001) in the SOC group. It is noteworthy that the Lp(a) level decreased by 13.2% in the PCSK9 group, but increased by 30.3% in the SOC group (P<0.001). Furthermore, the number of CV events was not significantly different between the PCSK9 and SOC groups after the 2-year follow-up period. In the PCSK9 group, the Lp(a) reduction was associated with the baseline Lp(a) levels of the patients (r2 =-0.315, P<0.001). Moreover, the decrease in Lp(a) contributed to the decline in CV events in patients who received ACS CHIPs-PCI, and the decrease in Lp(a) level was independent of the LDL-C level reduction. CONCLUSION: The early initiation of PCSK9 inhibitors can significantly reduce the LDL-C and Lp(a) levels in ACS CHIPs-PCI. However, further studies are needed to confirm whether PCSK9 inhibitors can reduce the incidence of CV disease in CHIPs.

Nimotuzumab plus induction chemotherapy followed by radiotherapy/concurrent chemoradiotherapy plus nimotuzumab for locally advanced nasopharyngeal carcinoma: protocol of a multicentre, open-label, single-arm, prospective phase II trial.

Epidermal growth factor receptor (EGFR) is a therapeutic target in nasopharyngeal carcinoma (NPC). The optimal combined modality of optimal combined modality of anti--EGFR monoclonal antibodies, induction chemotherapy (ICT), concurrent chemotherapy and radiotherapy for NPC remains poorly defined. None of previous studies have developed subsequent treatment strategies on the basis of stratification according to the efficacy following ICT plus anti-EGFR mAbs. This study aims to increase treatment intensity for patients with poor efficacy of ICT and reduce treatment toxicity for patients with favourable efficacy of ICT by assessing whether the efficacy of this treatment regimen is non-inferior to ICT plus concurrent chemoradiotherapy (historic controls). INTRODUCTION: METHODS AND ANALYSIS: Pathology-confirmed WHO type II/III NPC patients at clinical stage III-IVA (eighth American Joint Committee on Cancer/Union for International Cancer Control staging system) will be included in the study. They will receive ICT plus nimotuzumab (NTZ), followed by radiotherapy plus NTZ or concurrent chemoradiotherapy plus NTZ (stratified based on the efficacy of ICT plus NTZ). The primary endpoint is 3-year failure-free survival rate; while the secondary endpoints are 3-year overall survival rate, distant metastasis-free survival rate and locoregional recurrence-free survival rate, and short-term remission rate of tumour and treatment toxicity. ETHICS AND DISSEMINATION: The study protocol has been approved by the Ethics Committee of the Second Affiliated Hospital of Nanchang University. Our findings will be disseminated in a peer-reviewed journal. Implementation strategies are in place to ensure privacy and confidentiality of participants. TRIAL REGISTRATION NUMBER: ChiCTR2000041139.

Influence of LncRNA SDHAP1 on multiplication, migration and invasiveness of non-small cell lung carcinoma cells.

OBJECTIVE: To investigate the effects of lncRNA SDHAP1 on the multiplication, migration and invasiveness of NSCLC cells. METHODS: From The Cancer Genome Atlas (TCGA) database, the clinical data of NSCLC patients were retrieved to analyze the expression of lncRNA SDHAP1 in LC. In this study, lncRNA SDHAP1 in NSCLC cell lines was regulated, and its expression profiling in non- and cis-platinum (CDDP) resistant NSCLC cell lines was identified by qPCR. The levels of multidrug resistance-related protein 1 (MRP1), p-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) were measured by Western blotting (WB), the migration and invasion of LC cells were detected by Transwell assay, and the cell multiplication and activity were determined by MTT assays. RESULTS: TCGA database identified upregulated lncRNA SDHAP1 expression in LC. qPCR results revealed that lncRNA SDHAP1 was highly expressed in NSCLC. LncRNA SDHAP1 showed higher expression in patients with stage IV than in those with stage I, II or III, as well as in people aged 21-40 years old. Compared with normal lung epithelial cells, lncRNA SDHAP1 was upregulated in NSCLC cell lines, especially in those resistant to CDDP. LncRNA SDHAP1 downregulation led to a decrease in multiplication, migration and invasiveness of NSCLC cells, and a reduction in activity, migration and invasiveness of CDDP-resistant NSCLC cell lines. In addition, lncRNA SDHAP1 knockdown down-regulated the expression levels of Multidrug resistance-associated proteins MRP1, P-gp and GST-π. CONCLUSIONS: LncRNA SDHAP1 is upregulated in NSCLC and is associated with LC staging and age of patients. Silencing lncRNA SDHAP1 can suppress the multiplication, migration, invasiveness and CDDP resistance of cancer cells. Therefore, lncRNA SDHAP1 may serve as a prognostic biomarker and treatment target for NSCLC.

MiR-320 regulates cardiomyocyte apoptosis induced by ischemia-reperfusion injury by targeting AKIP1.

BACKGROUND: MicroRNAs play important roles in regulation of the cardiovascular system. The purpose of this study was to investigate microRNA-320 (miR-320) expression in myocardial ischemia-reperfusion (I/R) injury and the roles of miR-320 in cardiomyocyte apoptosis by targeting AKIP1 (A kinase interacting protein 1). METHODS: The level of miR-320 was detected using quantitative real-time polymerase chain reaction (qRT-PCR), and cardiomyocyte apoptosis was detected via terminal dUTP nick end-labeling assay. Cardiomyocyte apoptosis and the mitochondrial membrane potential were evaluated via flow cytometry. Bioinformatics tools were used to identify the target gene of miR-320. The expression levels of AKIP1 mRNA and protein were detected via qRT-PCR and Western blot, respectively. RESULTS: Both the level of miR-320 and the rate of cardiomyocyte apoptosis were substantially higher in the I/R group and H9c2 cells subjected to H/R than in the corresponding controls. Overexpression of miR-320 significantly promoted cardiomyocyte apoptosis and increased the loss of the mitochondrial membrane potential, whereas downregulation of miR-320 had an opposite effect. Luciferase reporter assay showed that miR-320 directly targets AKIP1. Moreover, knock down and overexpression of AKIP1 had similar effects on the H9c2 cells subjected to H/R. CONCLUSIONS: miR-320 plays an important role in regulating cardiomyocyte apoptosis induced by I/R injury by targeting AKIP1 and inducing the mitochondrial apoptotic pathway.

Semaphorin 3A attenuates electrical remodeling at infarct border zones in rats after myocardial infarction.

Electrical remodeling at infarct border zone has been shown to contribute to the occurrence of ventricular arrhythmias after myocardial infarction (MI). Electrical remodeling is causally associated with sympathetic neural remodeling in MI. Semaphorin 3A (Sema3A), a potent neural chemorepellent for sympathetic axons, has been demonstrated to suppress sympathetic neural remodeling after MI. In the present study, we investigated whether treatment with Sema3A can ameliorate electrical remodeling at infarct border zones using a rat model of MI. Wistar rats underwent sham operation (n = 20), the ligation of left coronary artery (MI group, n = 30), MI with control adenovirus (Ad group, n = 30), and MI with Sema3A adenovirus (Sema3A group, n = 30). Eight weeks after treatment, electrophysiological properties including heart rate variability (HRV), monophasic action potential duration (MAPD) and effective refractory period (ERP) and the expression of arrhythmia-related ion channel proteins including Kv4.2, KChIP2 and Kir2.1 at the infarcted border of the left ventricle were examined. These channel proteins may be required for maintaining normal heart rhythm. Compared with the Ad group, Sema3A significantly increased HRV and shortened MAPD and ERP (all p < 0.05). The expression levels of Kv4.2, KChIP2 and Kir2.1 proteins were significantly decreased in MI group and Ad group, compared to sham control. In contrast, the expression levels of these proteins were restored in Sema3A group, which may represent the molecular basis of the Sema3A-mediated inhibition of electrical remodeling. In conclusion, Sema3A can ameliorate electrical remodeling at infarct border zones after MI.

[Effects of sympathetic nerve stimulation on connexin43 and ventricular arrhythmias during acute myocardial ischemia: experiment with rats].

OBJECTIVE: To investigate the effects of sympathetic nerve stimulation (SNS) on connexin43 (Cx43) and ventricular arrhythmias during acute myocardial ischemia (MI). METHODS: Ninety five Wistar rats were randomly divided into four groups: MI group (n=25), undergoing: ligation of the anterior descending coronary; MII-SNS group (n=25); undergoing electric stimulation of sympathetic nerve since the beginning of ligation of the anterior descending coronary and lasting till 30 min after the ligation, sympathetic nerve stimulation preconditioning + myocardial ischemia (pSNS-MI) group (n=25), undergoing electric stimulation of sympathetic nerve since the beginning of ligation of the anterior descending coronary that ended just after the ligation; and sham operation (SO) group (n=20), without coronary ligation. Ventricular arrhythmias were monitored by electrocardiography. Western blotting and RT-PCR were used to detect the protein and mRNA expression of Cx43 respectively. Immunofluorescence analysis was used to observe the changes of Cx43 protein distribution. RESULTS: One and 3 rate died due to ventricular fibrillation in the MI group and MI-SS group respectively. The incidence of ventricular tachycardia (VT)/VF within 30-minute after ligation in the MI-SNS group was 80.0%, significant higher than that of the MI group (52.0%, P < 0.05). The incidence of VT/VF within 30-minute after ligation of the pSNS-MI group was 20.0%, significantly lower than that of the MI-SNS group (P < 0.05). 30 minutes after the ligation, the percentage of phosphorylated Cx43 of the pSNS-MI and MI-SNS groups were 71.2% +/- 7.0% and 73.4% +/- 6.7% respectively, both significantly higher than that of the MI group (46.7% +/- 6.3%) (both P < 0.05). The total contents of Cx43 of the MI and pSNS-MI groups were 1.29 +/- 0.14 and 1.25 +/- 0.13 respectively, both similar to that of the SO group [(1.30 +/- 0.10), both P > 0.05], while the total Cr43 content of the MI-SNS group was 0.73 +/- 0. 12, significantly lower than that of the SO group [(1.30 +/- 0.10), P < 0.05]. The Cx43 mRNA levels of the 3 experimental groups were all significantly lower than that of the SO group (all P < 0.05). Immunofluorescence analysis confirmed that ischemia and sympathetic nerve stimulation induced the changes of connexin43 distribution and sympathetic nerve stimulation preconditioning inhibited the changes of connexin43 distribution induced by ischemia. CONCLUSION: SNS promotes ventricular arrhythmias by promoting Cx43 degradation, and sympathetic nerve stimulation preconditioning inhibits ventricular arrhythmias by preventing Cx43 dephosphorylation.

[Relationship between sympathetic remodeling and electrical remodeling at infarcted border zone of rabbit with chronic myocardial infarction].

OBJECTIVE: To investigate the relationship between sympathetic remodeling and electrical remodeling at the infarcted border zone (IBZ) of rabbit with chronic myocardial infarction (MI). METHODS: Thirty rabbits were randomly assigned into two groups: MI group (n = 20): ligation of the anterior descending coronary; sham operation (SO) group (n = 10): without contrary ligation. Eight weeks after surgery, transmural dispersion of repolarization (TDR) at baseline, during sympathetic nerve stimulation, TDR change (DeltaTDR) during sympathetic nerve stimulation and ventricular fibrillation threshold (VFT) were measured at the IBZ in MI group and corresponding zone in SO group. The distribution and densities of growth associated protein 43 (GAP43) and tyrosine hydroxylase (TH) positive nerves in ventricle were also detected with immunohistochemical techniques. RESULTS: Eighteen rabbits in the MI group and 10 in the SO group survived to the end of the study. The densities of GAP43 and TH at the IBZ in the MI group were significantly higher than that at the corresponding zone in the SO group (both P < 0.05). The densities of GAP43 and TH in MI rabbits positively correlated with TDR at baseline, TDR or DeltaTDR during sympathetic nerve stimulation (all P < 0.01) and both showed a weak negative correlation with VFT (r =-0.44, P = 0.07; r = -0.41, P = 0.09, respectively). CONCLUSION: Sympathetic remodeling is correlated with electrical remodeling at the IBZ in rabbits with chronic MI.