1.Clinical value of conventional ultrasound combined with contrast-enhanced ultrasound in diagnosis of benign and malignant hypovascular renal tumors
Meijing FENG ; Xinping REN ; Junjian LI ; Lili ZHENG ; Lu ZHANG ; Weiwei ZHAN ; Yiyan DU
Academic Journal of Naval Medical University 2024;45(10):1304-1309
Objective To analyze the characteristics of conventional ultrasound and contrast-enhanced ultrasound(CEUS)in hypovascular renal tumors,and to explore the application value of combining the 2 methods in diagnosing benign and malignant hypovascular renal tumors.Methods The conventional ultrasound and CEUS data of 104 hypovascular renal tumors(76 benign lesions[benign group]and 28 malignant lesions[malignant group])from 99 patients,who were confirmed by postoperative pathology,biopsy pathology or computed tomography(CT)/magnetic resonance imaging(MRI)enhancement combined with long-term follow-up in Ruijin Hospital,Shanghai Jiao Tong University School of Medicine and its Wuxi Branch from Oct.13,2009 to Oct.26,2022,were retrospectively analyzed.The location,size,internal echo,morphology,internal and peripheral blood supply of the lesions were observed by conventional ultrasound,and the perfusion mode,regression pattern,perfusion uniformity and ring enhancement signs were observed by CEUS.Taking the pathological results or confirmed results of CT/MRI enhancement combined with long-term follow-up as the gold standard,the value of conventional ultrasound combined with CEUS in the differential diagnosis of benign and malignant hypovascular renal tumors was analyzed.Results There were significant differences in gender,age of patients and internal echo,contrast agent regression and ring enhancement signs of lesions between the 2 groups(all P<0.05).The malignant tumors were mostly found in males(78.6%,22/28)with an average age of(58.29±11.76)years old;the masses were mostly hypoechoic(64.3%,18/28),and rapid washout was predominant with CEUS(60.7%,17/28).In the benign group,most of the patients were female(55.3%,42/76),with an average age of(50.64±14.88)years old;the majority of the masses were hyperechoic(64.5%,49/76),and CEUS showed simultaneous washout as the main lesion(56.6%,43/76).Three patients(10.7%,3/28)with ring enhancement signs were all malignant.The diagnostic accuracy(82.7%)and specificity(88.2%)for benign and malignant hypovascular renal tumors were relatively high when combining the diagnostic indicators of ring enhancement signs and hypoechoic.The diagnostic sensitivity(85.7%)and negative predictive value(92.3%)were relatively high when combining the 3 diagnostic indicators of ring enhancement,hypoechoic,and rapid washout.Conclusion Conventional ultrasound combined with CEUS has significant clinical practical value in the differential diagnosis of benign and malignant hypovascular renal tumors.The ring enhancement sign is highly specific in the diagnosis of malignant hypovascular renal tumors.However,if this sign is not significant and conventional ultrasound shows hypoechoic or CEUS exhibits rapid washout,there is a strong suggestion that the mass may be a malignant lesion.
2.Exploring the role of methylation-driven gene IFFO1 in pancreatic adenocarcinoma diagnosis,prognosis and cellular functions
Ziqi XU ; Ruizhi HU ; Junjian LI ; Hongxia WANG ; Youzhou SANG
China Oncology 2024;34(11):998-1010
Background and purpose:Abnormal DNA methylation is closely associated with the onset and progression of tumors.This study aimed to investigate the expression of intermediate filament family orphan 1(IFFO1),a methylation-driven gene(MDG)in pancreatic adenocarcinoma(PAAD),along with its effects on the invasion and metastasis of PAAD cells,as well as its potential as a diagnostic and prognostic biomarker.Methods:mRNA expression data(TCGA-PAAD-mRNA),DNA methylation data(TCGA-PAAD-meth,GSE53051,PACA-AU)of PAAD and adjacent normal tissues,as well as DNA methylation data of healthy individuals'blood(GSE69270),were obtained from the The Cancer Genome Atlas(TCGA),International Cancer Genome Consortium(ICGC)and Gene Expression Omnibus(GEO)databases.By performing differential expression analysis combined with differential methylation analysis,we screened for MDG in PAAD.In the TCGA database,Pearson correlation tests were employed to verify the relationship between IFFO1 promoter methylation level and its expression level.Additionally,Kaplan-Meier survival analysis was conducted to evaluate the relationship among IFFO1 promoter methylation level,expression level,and the prognosis of PAAD.Pathological sections of cancer tissues and corresponding adjacent tissues from 27 PAAD patients were obtained from Shanghai General Hospital,Shanghai Jiao Tong University School of Medicine.All samples involved in this study were approved by the human ethics committee of Shanghai General Hospital,Shanghai Jiao Tong University School of Medicine(ethics number:hospital ethics review[2017]No.53).Immunohistochemistry staining(IHC)was utilized to detect the expression of IFFO1 in cancer tissues and corresponding adjacent tissues from 27 PAAD patients.Based on the median expression level of IFFO1,patients in the TCGA database were classified into high-expression and low-expression groups.Subsequently,differential analysis,gene ontology(GO)enrichment analysis and gene set enrichment analysis(GSEA)were performed.Western blot and real-time fluorescence quantitative polymerase chain reaction(RTFQ-PCR)were employed to assess the expression variations of IFFO1 between the normal pancreatic ductal epithelial cell line H6C7 and the PAAD cell lines MIA PaCa2,BxPC-3,AsPC-1 and Capan-2.The impact of IFFO1 overexpression on the migration and invasion capacities of PAAD cell lines AsPC-1 and Capan-2 was evaluated using scratch and invasion assays.Additionally,receiver operating characteristic(ROC)curves and Kaplan-Meier survival analysis were utilized to assess the diagnostic and prognostic significance of IFFO1 methylation levels in the TCGA pan-cancer cohort.Results:Through the cross-screening of five datasets,41 MDG in PAAD were identified.Among these,IFFO1 was found to be the gene most closely associated with the prognosis of PAAD[hazard ratio(HR)=0.28,P<0.001].IFFO1 exhibited high methylation and low expression levels in PAAD.Moreover,a significant negative correlation was observed between the methylation level of its promoter and its expression level(r=-0.55,P<0.001).IHC results indicated that IFFO1 expression was significantly lower in PAAD tissues than in adjacent non-tumor tissues(P<0.05).TCGA survival analysis demonstrated that patients with high methylation or low expression of IFFO1 had poorer overall survival(P<0.05).Both GO and GSEA analyses indicated that the pathway"Negative regulation of cell migration"was enriched in patients with high IFFO1 expression.Western blot and RTFQ-PCR results demonstrated that IFFO1 expression in normal pancreatic ductal epithelial cells H6C7 was significantly higher compared with PAAD cell lines MIA PaCa2,BxPC-3,AsPC-1,and Capan-2.Overexpression of IFFO1 significantly inhibited the migration and invasion of the PAAD cell lines AsPC-1 and Capan-2.Additionally,pan-cancer analysis revealed that IFFO1 exhibited abnormal promoter methylation and low expression across various cancer types,with its methylation levels demonstrating significant diagnostic and prognostic prediction value among different tumors.Conclusion:Promoter hypermethylation results in decreased expression of IFFO1 in PAAD.IFFO1 may suppress the invasion and migration abilities of PAAD cells.Furthermore,IFFO1 methylation holds great promise as a novel biomarker for the diagnosis and prognosis of PAAD.
3.Discovery of a highly potent and orally available importin-β1 inhibitor that overcomes enzalutamide-resistance in advanced prostate cancer.
Jia-Luo HUANG ; Xue-Long YAN ; Dong HUANG ; Lu GAN ; Huahua GAO ; Run-Zhu FAN ; Shen LI ; Fang-Yu YUAN ; Xinying ZHU ; Gui-Hua TANG ; Hong-Wu CHEN ; Junjian WANG ; Sheng YIN
Acta Pharmaceutica Sinica B 2023;13(12):4934-4944
Nuclear transporter importin-β1 is emerging as an attractive target by virtue of its prevalence in many cancers. However, the lack of druggable inhibitors restricts its therapeutic proof of concept. In the present work, we optimized a natural importin-β1 inhibitor DD1 to afford an improved analog DD1-Br with better tolerability (>25 folds) and oral bioavailability. DD1-Br inhibited the survival of castration-resistant prostate cancer (CRPC) cells with sub-nanomolar potency and completely prevented tumor growth in resistant CRPC models both in monotherapy (0.5 mg/kg) and in enzalutamide-combination therapy. Mechanistic study revealed that by targeting importin-β1, DD1-Br markedly inhibited the nuclear accumulation of multiple CRPC drivers, particularly AR-V7, a main contributor to enzalutamide resistance, leading to the integral suppression of downstream oncogenic signaling. This study provides a promising lead for CRPC and demonstrates the potential of overcoming drug resistance in advanced CRPC via targeting importin-β1.
4.Comparison of laparoscopic and open surgery in the treatment of Mirizzi syndrome
Ming LI ; Dapeng ZHANG ; Xiaojun SUI ; Junjian LIU ; Ning LI ; Zhenyu WANG
Chinese Journal of Hepatobiliary Surgery 2023;29(12):897-901
Objective:To compare the laparoscopic and open surgery in the treatment of Mirizzi syndrome (MS).Methods:The clinical data of 125 patients with MS undergoing surgery in Tianjin Nankai Hospital from May 2013 to April 2020 were retrospectively analyzed, including 59 males and 66 females, aged (57.7±13.6) years old. Patients were divided into the laparoscopic group ( n=84) and open group ( n=41). General data, operation time, intraoperative blood loss, postoperative complications, postoperative and total hospital were compared between the groups. Patients were followed up and screened for biliary stone recurrence or biliary stenosis by phone or Wechat. Results:The postoperative hospital stay [8.00(5.25, 12.00) d vs. 13.00(10.00, 17.50) d, P<0.001] and total hospital stay [15.00 (10.25, 22.75) d vs. 22.00 (16.00, 27.50) d, P<0.001] were shorter in laparoscopic group. The conversion rate of laparoscopic group was 15.5% (13/84). No perioperative death occurred in either group. The incidence of postoperative complications were comparable between the groups [9.5%(8/84) vs. 7.3%(3/41), P>0.05]. In laparoscopic group, 64 patients were followed up [76.2% (64/84)]. During follow-up, there were two deaths, five cases of bile duct stones recurrence and one case of bile duct stenosis. In open group, 37 patients were followed up [90.2% (37/41)]. During follow-up, there were four deaths, four cases of bile duct stones recurrence. All deaths during follow-ups were non-MS-related. Conclusion:Compared to open surgery, laparoscopic surgery could shorten the total/postoperative hospital stay while does not increase the morbidity and mortality, which could be safe and feasible in the treatment of MS.
5.Role of HBV DNA polymerase in mediating the immune escape of tumor cells in HBV-related hepatocellular carcinoma
Hongxia LI ; Yimeng SUN ; Hongtao ZHANG ; Shuwang HAN ; Delin ZHANG ; Haitao SHANG ; Wu GUO ; Junjian LIU ; Zhonglian LI
Journal of Clinical Hepatology 2023;39(12):2858-2866
ObjectiveTo determine whether HBV DNA polymerase is associated with T-cell failure and thus mediates the immune escape of HBV-related hepatocellular carcinoma (HCC) tumor cells, and to investigate the specific molecular mechanisms. MethodsLiver cancer cell lines Huh7 and HepG2 stably transfected with HBV DNA polymerase expression plasmid with Flag (Flag-HBV-P) and intercellular adhesion molecule-1 (ICAM1) were co-cultured with Jurkat cells, and MTT assay, qRT-PCR, and ELISA were used to measure Jurkat cell proliferation, activation (CD69 expression), and secretion of the cytokine IFN-γ. RNA-seq was used to screen for differentially expressed immune-associated molecules between stably transfected cell lines and control cells, and mRNA half-life and protein half-life assays were used to determine the specific levels of the immune-associated molecules that were affected by HBV DNA polymerase. Related websites were used to predict the transcription factors that may bind to the promoter region of this immune-associated molecule, Western blot was used to verify the effect of transcription factors on the immune-associated molecule, and rescue experiment was used to determine whether HBV DNA polymerase affects the expression level of the immune-associated molecule through this transcription factor. The independent-samples t test was used for comparison between two groups. ResultsThe experimental group had significant reductions in Jurkat cell proliferation, activation, and cytokine secretion compared with the control group (all P<0.01). Compared with the control group, the experimental group (Huh7 and HepG2 cell lines) had significant reductions in the mRNA and protein expression levels of ICAM1 (all P<0.01). Website prediction identified the ICAM1 promoter and preliminarily highlighted NFKB1, RELA, and STAT3. Compared with the control group, the experimental group (Huh7 and HepG2 cell lines) had a significant reduction in the protein expression level of p65 (all P<0.01). After p65 overexpression, there was a significant increase in the protein expression level of ICAM1, and after the expression of p65 was reduced, there was a significant reduction in the protein expression level of ICAM1 (all P<0.01). In the rescue experiment, there was no significant difference in the protein expression level of ICAM1 between the control group and the experimental group after p65 overexpression (all P>0.05). After the overexpression of ICAM1, there were no significant differences in the proliferation, activation, and cytokine secretion of Jurkat cells between the control group and the experimental group (Huh7 and HepG2 cell lines) (all P>0.05). ConclusionHBV DNA polymerase downregulates the level of ICAM1 to mediate HCC immune escape by inhibiting the expression of p65 in NF-κB.
6.Effect of Yinchenhao decoction on renal oxidative stress injury in rats with obstructive jaundice and its mechanism of action based on the nuclear factor erythroid 2-related factor 2 signaling pathway
Junjian LIU ; Shuai CHEN ; Hongxia YUAN ; Yan XU ; Xibo ZHANG ; Zhonglian LI
Journal of Clinical Hepatology 2023;39(5):1126-1133
Objective To investigate the effect of Yinchenhao decoction on renal oxidative stress injury in rats with obstructive jaundice and its association with the regulation of the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear translocation. Methods A total of 32 male Sprague-Dawley rats were randomly divided into sham-operation group (S group), model group (O group), low-dose Yinchenhao decoction group (LY group), and high-dose Yinchenhao decoction group (HY group), with 8 rats in each group. For the rats in the S group, the upper common bile duct was isolated without ligation, and for those in the other groups, double ligation of the middle and upper 1/3 of the common bile duct was performed to establish a model of obstructive jaundice. After 7 days, the rats in the LY group and the HY group were given Yinchenhao decoction by gavage at a dose of 6.3 and 18.9 mL/kg, respectively, while those in the S and O groups were given an equal volume of distilled water by gavage every day for 7 consecutive days, and the rats were treated on day 14. ELISA was used to measure the serum levels of total bilirubin (TBil), direct bilirubin (DBil), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), blood urea nitrogen (BUN), and creatinine (Cr); spectrophotometry was used to measure the activity of the oxidative stress factors superoxide dismutase (SOD) and malondialdehyde (MDA) in renal tissue; quantitative real- time PCR and Western blotting were used to measure the mRNA and protein expression levels of Nrf2, Kelch-like ECH-associated protein 1 (Keap1), and NAD(P)H quinone dehydrogenase 1 (NQO1) in renal tissue; immunohistochemistry was used to measure observe the nuclear translocation of Nrf2 protein in renal tissue. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t -test was used for further pairwise comparison within groups. Results Compared with the S group, the O group had significant increases in the levels of TBil, DBil, ALT、GGT, BUN, and Cr, a significant reduction in the activity of SOD, and a significant increase in the level of MDA (all P < 0.05). Compared with the O group, the LY group and the HY group had significant reductions in liver and renal function parameters, a significant increase in the activity of SOD, and a significant reduction in the level of MDA (all P < 0.05). Compared with the S group, the O group had significant reductions in the mRNA and protein expression levels of Nrf2 and NQO1 in renal tissue (all P < 0.05), and compared with the O group, the LY group and the HY group had significant increases in the mRNA and protein expression levels of Nrf2 and NQO1 (all P < 0.05), while there was no significant difference in the protein expression level of Keap1 between groups ( P > 0.05). Compared with the S group, the O group had a significant reduction in the positive rate of Nrf2 in cell nucleus in renal tissue ( P < 0.05), and compared with the O group, the LY group and the HY group had a significant increase in the positive rate of Nrf2 in cell nucleus ( P < 0.05). Conclusion Yinchenhao decoction can effectively alleviate renal injury caused by obstructive jaundice, possibly by upregulating the protein expression of Nrf2 in renal tissue and regulating the nuclear translocation of Nrf2 protein, so as to mediate the protein expression of downstream NQO1, regulate oxidative stress response caused by obstructive jaundice, and thereby alleviate renal injury in rats.
7.Predictive value of different critical values of slow gait speed on adverse outcomes in elderly maintenance hemodialysis patients
Jiangbin MO ; Li HUANG ; Junjian QIN ; Bo LIANG
Chinese Journal of Nephrology 2023;39(2):119-125
Objective:To explore the predictive value of different critical values of slow gait speed on adverse outcomes in elderly maintenance hemodialysis (MHD) patients.Methods:The study was a prospective cohort study. The clinical data of elderly patients (≥ 60 years old) who received MHD treatment in the Third Affiliated Hospital of Guangzhou Medical University from March 1 to June 30, 2021 were collected, including demographic characteristics, diseases-related data and laboratory examination results. The follow-up period was one year. The six-meter walking test was used to measure the gait speed (m/s), and 0.6 m/s, 0.8 m/s and 1.0 m/s were used as the different critical values of the gait speed for grouping. The differences of clinical data between different groups were compared. Logistic regression analysis method was used to assess the association of slow gait speed with adverse outcomes (falls and hospitalization) in elderly MHD patients. The receiver operating characteristic (ROC) curve was performed to evaluate the best critical value of slow gait speed to predict the risk of falls and hospitalization.Results:A total of 108 elderly patients with MHD were included, with 57 males and 51 females. There were 43 patients (39.8%) of falls and 34 patients (31.5%) of hospitalization. There were statistically significant differences in age, Charlson's comorbidity index, and the proportions of hypertension, family support needed in daily life, walking aids needed, falls and hospitalization events among the four groups of the patients grouped according to gait speed (all P < 0.05). Multivariate logistic regression analysis results showed that the risk of falls predicted by gait speed of 0.6- < 0.8 m/s was higher than that by gait speed of > 1.0 m/s ( OR=3.973, 95% CI 1.116-14.136, P=0.033). The risk of hospitalization predicted by gait speed < 0.6 m/s was higher than that by gait speed > 1.0 m/s ( OR=9.147, 95% CI 1.658-50.453, P=0.011). The logistic regression analysis was performed with the critical values of 0.6 m/s, 0.8 m/s and 1.0 m/s as the classification variables, and the results showed that the gait speed of < 0.8 m/s was an influencing factor of the falls risk in elderly MHD patients (≥ 0.8 m/s as reference, OR=3.200, 95% CI 1.099-9.318, P=0.033). The gait speed < 0.8 m/s and < 0.6 m/s were influencing factors of hospitalization (≥ 0.8 m/s as reference, OR=3.899, 95% CI 1.355-11.216, P=0.012; ≥ 0.6 m/s as reference, OR=4.226, 95% CI 1.107-16.140, P=0.035). The area under the ROC curve for gait speed of < 0.6 m/s, < 0.8 m/s and < 1.0 m/s to predict the risk of falls were 0.605(95% CI 0.493-0.717, P=0.065), 0.668(95% CI 0.562-0.774, P=0.003), and 0.634 (95% CI 0.529-0.739, P=0.019), respectively. The best critical value of slow gait speed to predict the risk of fall was 0.73 m/s, and the area under the ROC curve was 0.720(95% CI 0.623-0.817, P < 0.001), with the sensitivity and specificity of 0.846 and 0.512, respectively. The area under the ROC curve for gait speed of < 0.6 m/s, < 0.8 m/s and < 1.0 m/s to predict the risk of hospitalization were 0.629(95% CI 0.509-0.749, P=0.032),0.683(95% CI 0.573-0.793, P=0.002), and 0.608(95% CI 0.497- 0.719, P=0.073). The best critical value of slow gait speed to predict the risk of hospitalization was 0.81 m/s, and the area under the ROC curve was 0.688(95% CI 0.576-0.800, P=0.002), with the sensitivity and specificity of 0.689 and 0.676, respectively. Conclusion:The critical value of gait speed 0.8 m/s can be used to predict the risk of falls and hospitalization in elderly MHD patients.
8.Value of contrast-enhanced ultrasound in differentiating benign and malignant gallbladder lesions which diameter more than 1 cm
Meijing FENG ; Xinping REN ; Weiwei ZHAN ; Lili ZHENG ; Junjian LI
Journal of Surgery Concepts & Practice 2023;28(6):556-562
Objective To investigate the clinical value of contrast-enhanced ultrasound(CEUS)in differential diagnosis between benign and malignant gallbladder lesions which diameter more than 1 cm.Methods A retrospective analysis included CEUS data of 142 cases with gallbladder lesions diameter more than 1 cm.All lesions were confirmed by surgical pathology,enhanced CT/MRI or clinical diagnosis with following up more than 2 years.To summarize the CEUS characteristics of benign and malignant gallbladder lesions over 1 cm in diameter,the CEUS characteristics of benign and malignant gallbladder lesions diameter more than 1 cm were analyzed,referring to the gallbladder CEUS guidelines.The contrast medium washout before 35 s and 60 s were used as the combined diagnosis with CEUS standard to identify gallbladder cancer,and the diagnostic efficiency was calculated respectively.Results There were statistical differences between the malignant group and the benign group in terms of CEUS enhancement pattern,contrast arrival time,washout time,and gallbladder wall continuity,as well as enhancement levels(P<0.001).The sensitivity,specificity,accuracy in the diagnosis of gallbladder malignant lesions were 93.0%,83.8%,and 86.6%based on CEUS standard.The sensitivity,specificity and accuracy of diagnosis gallbladder malignant lesions were increased to 93.0%,92.9%and 93.0%when combined with washout before 35 s of contrast medium.Conclusions CEUS is highly valuable in differentiating benign and malignant gallbladder lesions diameter more than 1 cm.Combined with contrast medium washout before 35 s is helpful to improve the ability of differentiating benign and malignant gallbladder lesions.
9.Congenital malignant rhabdoid tumor in a fetal neck: a case report
Bo XIA ; Qiuming HE ; Junjie WANG ; Junjian LYU ; Jiahua LI
Chinese Journal of Perinatal Medicine 2021;24(10):774-777
We report the clinical characteristics of congenital malignant rhabdoid tumor (MRT) of the neck in a fetus. Prenatal ultrasound and MRI at 33 +4 and 34 weeks gestation revealed a round solid mass on the right side of the fetus' neck. An initial differential diagnosis was between neuroblastoma and vascular malformation. Re-examination with ultrasound at 36 gestational weeks revealed an enlarged fetal neck mass, with concomitant multiple subcutaneous solid masses all over his body, right-side hydrothorax, and abnormal liver echo, which were highly suspicious of metastasis of a malignant tumor. The baby boy was delivered by cesarean section at 37 weeks of gestation with a normal Apgar score and slight shortness of breath. Physical examination showed scattered lesions in the neck, armpits, and limbs, etc. The condition of the infant deteriorated rapidly with the increasing number and volume of the masses after admission. The boy was confirmed as MRT (stage Ⅳ) by pathological biopsy on the left upper arm and died on postnatal day 10 after treatment was withdrawn.
10.The poly(ADP-ribosyl)ation of BRD4 mediated by PARP1 promoted pathological cardiac hypertrophy.
Zhenzhen LI ; Zhen GUO ; Rui LAN ; Sidong CAI ; Zhirong LIN ; Jingyan LI ; Junjian WANG ; Zhuoming LI ; Peiqing LIU
Acta Pharmaceutica Sinica B 2021;11(5):1286-1299
The bromodomain and extraterminal (BET) family member BRD4 is pivotal in the pathogenesis of cardiac hypertrophy. BRD4 induces hypertrophic gene expression by binding to the acetylated chromatin, facilitating the phosphorylation of RNA polymerases II (Pol II) and leading to transcription elongation. The present study identified a novel post-translational modification of BRD4: poly(ADP-ribosyl)ation (PARylation), that was mediated by poly(ADP-ribose)polymerase-1 (PARP1) in cardiac hypertrophy. BRD4 silencing or BET inhibitors JQ1 and MS417 prevented cardiac hypertrophic responses induced by isoproterenol (ISO), whereas overexpression of BRD4 promoted cardiac hypertrophy, confirming the critical role of BRD4 in pathological cardiac hypertrophy. PARP1 was activated in ISO-induced cardiac hypertrophy and facilitated the development of cardiac hypertrophy. BRD4 was involved in the prohypertrophic effect of PARP1, as implied by the observations that BRD4 inhibition or silencing reversed PARP1-induced hypertrophic responses, and that BRD4 overexpression suppressed the anti-hypertrophic effect of PARP1 inhibitors. Interactions of BRD4 and PARP1 were observed by co-immunoprecipitation and immunofluorescence. PARylation of BRD4 induced by PARP1 was investigated by PARylation assays. In response to hypertrophic stimuli like ISO, PARylation level of BRD4 was elevated, along with enhanced interactions between BRD4 and PARP1. By investigating the PARylation of truncation mutants of BRD4, the C-terminal domain (CTD) was identified as the PARylation modification sites of BRD4. PARylation of BRD4 facilitated its binding to the transcription start sites (TSS) of hypertrophic genes, resulting in enhanced phosphorylation of RNA Pol II and transcription activation of hypertrophic genes. The present findings suggest that strategies targeting inhibition of PARP1-BRD4 might have therapeutic potential for pathological cardiac hypertrophy.

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