Ntsr1 contributes to pulmonary hypertension by enhancing endoplasmic reticulum stress via JAK2-STAT3-Thbs1 signaling.

Pulmonary hypertension (PH) is a severe clinical syndrome with pulmonary vascular remodeling and poor long-term prognosis. Neurotensin receptor 1 (Ntsr1), serve as one of the G protein-coupled receptors (GPCRs), implicates in various biological processes, but the potential effects of Ntsr1 in PH development are unclear. The Sugen/Hypoxia (SuHx) or monocrotaline (MCT) induced rat PH model was used in our study and the PH rats showed aggravated pulmonary artery remodeling and increased right ventricular systolic pressure (RVSP). Our results revealed that Ntsr1 induced endoplasmic reticulum (ER) stress response via ATF6 activation contributed to the development of PH. Moreover, RNA-sequencing (RNA-seq) and phosphoproteomics were performed and the Ntsr1-JAK2-STAT3-thrombospondin 1 (Thbs1)-ATF6 signaling was distinguished as the key pathway. In vitro, pulmonary artery smooth muscle cells (PASMCs) under hypoxia condition showed enhanced proliferation and migration properties, which could be inhibited by Ntsr1 knockdown, JAK2 inhibitor (Fedratinib) treatment, STAT3 inhibitior (Stattic) treatment, Thbs1 knockdown or ATF6 knockdown. In addition, adeno-associated virus 1 (AAV1) were used to knockdown the expression of Ntsr1, Thbs1 or ATF6 in rats and reversed the phenotype of PH. In summary, our results reveal that Ntsr1-JAK2-STAT3-Thbs1 pathway can induce enhanced ER stress via ATF6 activation and increased PASMC proliferation and migration capacities, which can be mechanism of the pulmonary artery remodeling and PH. Targeting Ntsr1 might be a novel therapeutic strategy to ameliorate PH.

Zbtb16 increases susceptibility of atrial fibrillation in type 2 diabetic mice via Txnip-Trx2 signaling.

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia, and recent epidemiological studies suggested type 2 diabetes mellitus (T2DM) is an independent risk factor for the development of AF. Zinc finger and BTB (broad-complex, tram-track and bric-a-brac) domain containing 16 (Zbtb16) serve as transcriptional factors to regulate many biological processes. However, the potential effects of Zbtb16 in AF under T2DM condition remain unclear. Here, we reported that db/db mice displayed higher AF vulnerability and Zbtb16 was identified as the most significantly enriched gene by RNA sequencing (RNA-seq) analysis in atrium. In addition, thioredoxin interacting protein (Txnip) was distinguished as the key downstream gene of Zbtb16 by Cleavage Under Targets and Tagmentation (CUT&Tag) assay. Mechanistically, increased Txnip combined with thioredoxin 2 (Trx2) in mitochondrion induced excess reactive oxygen species (ROS) release, calcium/calmodulin-dependent protein kinase II (CaMKII) overactivation, and spontaneous Ca2+ waves (SCWs) occurrence, which could be inhibited through atrial-specific knockdown (KD) of Zbtb16 or Txnip by adeno-associated virus 9 (AAV9) or Mito-TEMPO treatment. High glucose (HG)-treated HL-1 cells were used to mimic the setting of diabetic in vitro. Zbtb16-Txnip-Trx2 signaling-induced excess ROS release and CaMKII activation were also verified in HL-1 cells under HG condition. Furthermore, atrial-specific Zbtb16 or Txnip-KD reduced incidence and duration of AF in db/db mice. Altogether, we demonstrated that interrupting Zbtb16-Txnip-Trx2 signaling in atrium could decrease AF susceptibility via reducing ROS release and CaMKII activation in the setting of T2DM.

The association of growth differentiation factor 5 rs143383 gene polymorphism with osteoarthritis: a systematic review and meta-analysis.

BACKGROUND: Osteoarthritis (OA) is caused by a complex set of pathophysiological factors. The genetic factors involved in the occurrence and progress of the disease have been widely discussed by scholars. It was found that growth differentiation factor 5 (GDF5) gene polymorphisms may be linked to OA susceptibility, which has been controversial and needs to be further confirmed by an updated meta-analysis. OBJECTIVES: We examined the association between GDF5 rs143383 single nucleotide polymorphism (SNP) and OA susceptibility. METHODS: All relevant articles that met the criteria are retrieved and included, and the search deadline is June 2022. The allele frequencies and different genotype frequencies of GDF5 rs143383 loci in each study were extracted and statistically analyzed by R4.1.3 software, and the different genetic models were analyzed based on their odds ratio (OR) and 95% confidence interval (CI). RESULTS: The meta-analysis explained that GDF5 rs143383 SNP was crucial correlated with OA in all patients with OA of knee, hip and hand. The codominant gene model in the whole crowd (OR = 1.17, 95% CI 1.07-1.27, P < 0.01) enlightened that OA was vitally associated with GDF5 gene polymorphism. At the same time, we did a subgroup analysis based on ethnicity. The codominant gene model (OR = 1.31, 95% CI 1.12-1.53, P < 0.01) in Asian population, the codominant homozygote model (OR = 1.28, 95% CI 1.14-1.43), codominant heterozygote gene model (OR = 1.12, 95% CI 1.01-1.23, P = 0.02), and dominant gene model (OR = 1.19, 95% CI 1.09-1.31, P < 0.01) in Caucasian are analyzed by subgroup analysis. It means that there is a momentous relationship between the GDF5rs143383 gene polymorphism and OA, especially among Caucasians. In addition, we also discussed different types of OA separately and discover that the GDF5rs143383 gene polymorphism was relevant for knee osteoarthritis (KOA) and hand osteoarthritis, and it was more significant in the Caucasian population. But due to the high heterogeneity in hip osteoarthritis, it could not be accurately concluded. Furthermore, we also analyzed the osteoarthritis of different genders and found that the GDF5 rs143383 SNP was associated with both men and women and was still significant in the Caucasian population. CONCLUSION: We found a close association between osteoarthritis and GDF5rs143383SNP in this study. From the analysis of each group, we got the same conclusion in KOA and hand OA, but which need further verification in hip OA. Considering gender, we found a close relationship between GDF5 rs143383 SNP and OA of the knee, hip and hand, both for men and women. This conclusion is more obvious in Caucasian people.

Multimodality imaging in diagnosing lipomatous atrial septal hypertrophy with atrial septal defect: a case report.

Background: Lipomatous atrial septal hypertrophy (LASH) with atrial septal defect (ASD) is a rare congenital anomaly. Although LASH is a histologically benign cardiac lesion characterized by excessive fat deposition in the interatrial septum that spares the fossa ovale, it has been associated with supraventricular arrhythmias or sick sinus syndrome. Application of multimodal imaging is crucial for accurate diagnosis, appropriate treatment of LASH with ASD, and follow-up. Case summary: A 68-year-old female patient presented with recurrent chest tightness and palpitation. Multimodal imaging revealed the characterizations of LASH and ASD. Two-dimensional transesophageal echocardiography showed a "dumbbell"-shaped involvement of the cephalad and caudal regions with sparing of a single secundum ASD. The septum with a brightness feature is an uncommon condition characterized by the deposition of unencapsulated fat cells in the atrial septum. Real-time four-dimensional transesophageal echocardiography reflected the lipomatous hypertrophy of the atrial septum and an oval-shaped ASD. Cardiac computer tomography angiography later confirmed this finding. The patient achieved a good clinical response with an ASD percutaneous occlusion guided by intracardiac echocardiography (ICE). Conclusion: This case demonstrates a LASH combined with ASD. Multimodality imaging can provide an accurate diagnosis and may guide the procedure for precise occlusion.

A rare presentation of Maffucci syndrome: A case report and literature review.

Maffucci syndrome is an extremely rare disease which can manifest symptoms as early as childhood. It is estimated that there have been <300 cases reported globally; however, this number is likely to be an underestimate. Maffucci syndrome is characterized by multiple enchondromas and soft tissue hemangiomas, which can cause growth and developmental malformations. In addition to bone deformities, pathological fractures and a loss of mobility, patients with Maffucci syndrome may develop secondary central chondrosarcoma and have a higher risk of developing non-skeletal malignant tumors, such as gliomas and mesenchymal ovarian tumors. The present study provides information for clinicians about this disease through the use of imaging, physical examinations, clinical manifestations and the treatment strategy used. There is need to summarize the existing cases of this disease around the world and produce an effective framework for the diagnosis, treatment and prevention of Maffucci syndrome, in order to better understand this disease. The present study reports on a 15-year-old male diagnosed with Maffucci syndrome. . Due to the risk of malignant tumor development in the absence of effective treatment, regular and careful observation through monitoring of tumor markers and imaging studies is important for patients with Maffucci syndrome. As cases of this disease are rare and case data is limited, it is difficult to create a clear treatment plan. There is an urgent need to establish a case database of Maffucci syndrome patients and explore its pathogenesis for early diagnosis, treatment and prevention of disease.

Efficacy and safety of unilateral biportal endoscopy compared with microscopic decompression in the treatment of lumbar spinal stenosis: A systematic review and updated meta­analysis.

The incidence of lumbar spinal stenosis is increasing annually, and with an ever-aging population and longer life expectancies, this trend will further continue. It is hoped that a more effective treatment can be found so that the patients can be relieved of their pain. The aim of this systematic review and meta-analysis was to evaluate the effectiveness and safety of unilateral biportal endoscopic surgery (UBE) and microscopic decompression surgery (MD) for the treatment of lumbar spinal stenosis. A literature search of related studies published until April 2022 was performed using PubMed, EMBASE, Cochrane Library, Web of Science, ClinicalTrials.gov, Google Scholar, China National Knowledge Infrastructure (CNKI), and other databases. After filtering of references, 12 eligible studies were identified that compared UBE with MD as a treatment for lumbar spinal stenosis. Data were extracted and analysed using R. A total of 12 articles (four randomized controlled and eight cohort studies) were included, with a total of 1,067 patients: 250 men and 249 women in the UBE group and 290 men and 278 women in the MD group. The meta-analysis showed that the mean intraoperative blood loss in the UBE group [standardized mean difference (SMD)=-2.10, 95% confidence interval (CI) (-3.97, -0.23), P=0.03] was lower than that in the MD group. The postoperative Visual analogue scale (VAS) score for back pain [SMD=-0.52, 95% CI (-0.76, -0.27), P<0.01], leg pain [SMD=-0.30, 95% CI (-0.51, -0.08), P<0.01], postoperative Oswestry disability index [(ODI); SMD=-0.25, 95% CI (-0.48, -0.03), P=0.03], and postoperative C-reactive protein [(CRP); odds ratio (OR)=-0.92, 95% CI (-1.80, 0.03), P=0.04] were lower than those in the MD group. Complications (OR=0.60, 95% CI (0.37, 0.98), P=0.04) and hospital stay (SMD=-1.84, 95% CI (-2.85, 0.83), P <0.01] were also lesser in the UBE group than in the MD group. UBE was preferable to that in the MD group according to the modified MacNab score [OR=2.28, 95% CI (1.28, 4.06), P<0.01]. No significant differences were observed in the operation times between the groups. UBE surgery was found to be a better option for the treatment of lumbar spinal stenosis than MD surgery.

The association between ADAM12 gene polymorphisms and osteoarthritis: an updated meta-analysis.

BACKGROUND: Osteoarthritis of the knee is an irreversible disease that causes great pain, and genetic factors play an important role in its occurrence and development. There have been many studies on the correlation between ADAM12 polymorphisms and genetic susceptibility to osteoarthritis, but the results remain inconclusive. METHODS: Papers from PubMed, Web of Science, EMbase, Springer, SCOPUS, Google Scholar and other databases were systematically retrieved with a cut-off of January 2022. All case-control studies on ADAM12 rs3740199, rs1871054, rs1044122, and rs1278279 polymorphisms and osteoarthritis were searched. Fixed or random effects models were used for pooled analysis with OR values and 95% confidence intervals (CI), and publication bias was assessed. In addition, the false-positive reporting probability test was used to assess the confidence of a statistically significant association. RESULTS: Eleven articles were included, which included 3332 patients with osteoarthritis and 5108 healthy controls. Meta-analysis showed that the rs1871054 polymorphism of ADAM12 was associated with osteoarthritis in dominant, recessive, allelic, and homozygote genetic models [C vs. T: OR = 1.34 95% CI (1.05, 1.71), P < 0.001]. Our subgroup analysis revealed an association between the ADAM12 polymorphism rs1871054 in Asians and osteoarthritis [C vs. T: OR = 1.61, 95% CI (1.25, 2.08), P < 0.001], albeit this was only for three studies. In addition, the ADAM12 polymorphism rs1871054 is associated with osteoarthritis in patients younger than 60 years of age [C vs. T: OR = 1.39, 95% CI (1.01, 1.92), P = 0.289]; however, the ADAM12 gene rs3740199, rs1044122, and rs1278279 site polymorphisms were not significantly. Furthermore, when assessing the confidence of the positive results, the positive results were found to be credible (except for Age < 60). CONCLUSION: Polymorphism at the rs1871054 site of ADAM12 is associated with genetic susceptibility to osteoarthritis, but rs3740199, rs1044122, and rs1278279 site polymorphisms are not.

Macrophages facilitate post myocardial infarction arrhythmias: roles of gap junction and KCa3.1.

Effective therapeutic targets against post-myocardial infarction (MI) arrhythmias remain to be discovered. We aimed to investigate the role of macrophages in post-MI arrhythmias. Methods: Mononuclear cell accumulation, macrophage polarization from M0 to M1 subset, and gap junction formation were analyzed in MI patients and MI mice by flow cytometry, immunofluorescence and patch clamping. Differentially expressed genes were identified by RNA sequencing. Macrophages and cardiomyocytes were cocultured in vitro, and the effects of gap junction and KCa3.1 on electrophysiological properties were assessed by patch clamping. The effects of KCa3.1 inhibition on post-MI arrhythmias were assessed by intracardiac stimulation and ambulatory electrocardiograms in vivo. Results: Percentage of pro-inflammatory mononuclear cells were significantly elevated in patients with post-MI arrhythmias compared with MI patients without arrhythmias and healthy controls (p<0.001). Macrophages formed gap junction with cardiomyocytes in MI border zones of MI patient and mice, and pro-inflammatory macrophages were significantly increased 3 days post-MI (p<0.001). RNA sequencing identified Kcnn4 as the most differentially expressed gene encoding ion channel, and the upregulation is mainly attributed to macrophage accumulation and polarization into pro-inflammatory subset. In vitro coculture experiments demonstrated that connection with M0 macrophages via gap junction slightly shortened the action potential durations (APDs) of cardiomyocytes. However, the APD90 of cardiomyocytes connected with M1 macrophages were significantly prolonged (p<0.001), which were effectively attenuated by gap junction inhibition (p=0.002), KCa3.1 inhibition (p=0.008), KCa3.1 silencing (p<0.001) and store-operated Ca2+ channel inhibition (p=0.005). In vivo results demonstrated that KCa3.1 inhibition significantly decreased the QTc durations (p=0.031), intracardiac stimulation-induced ventricular arrhythmia durations (p=0.050) and incidence of premature ventricular contractions (p=0.030) in MI mice. Conclusion: Macrophage polarization leads to APD heterogeneity and post-MI arrhythmias via gap junction and KCa3.1 activation. The results provide evidences of a novel mechanism of post-MI heterogeneous repolarization and arrhythmias, rendering macrophages and KCa3.1 to be potential therapeutic targets.

Partial inhibition of activin receptor-like kinase 4 attenuates pressure overload-induced cardiac fibrosis and improves cardiac function.

BACKGROUND: Activin receptor-like kinase 4 (ALK4), a downstream receptor of transforming growth factor-ß superfamily, is highly expressed in the mammal heart. Upregulated ALK4 expression and activated ALK4-small mother against decapentaplegic (Smad)2/3 signaling have been reported to play a pivotal role in tumorigenesis and in the development of systemic sclerosis. However, the role of ALK4-Smad2/3 pathway in the pathogenesis of cardiac hypertrophy and cardiac fibrosis remains unknown. METHODS AND RESULTS: In this study, the mice with heterozygous knocking out of ALK4 gene (ALK4) were generated and subjected to aortic banding for 4 weeks. We found that ALK4 expression was upregulated in aortic banding-induced model of cardiac hypertrophy and cardiac fibrosis in wild-type mice. Compared with the wild-type mice, ALK4mice demonstrated a similar extent of aortic banding-induced cardiac hypertrophy, but a significant suppression of cardiac fibrosis to 64.8% of the basal level, and a subsequent amelioration in the cardiac dysfunction (left ventricle ejection fraction: 59.0 ±â€Š6.4 in wild-type mice vs. 75.6 ±â€Š3.9% in ALK4 mice; left ventricle end-diastolic pressure: 16.6 ±â€Š4.7 mmHg in wild-type mice vs. 6.6 ±â€Š2.8 mmHg in ALK4 mice) associated with inhibition of cardiac fibroblast activation and cardiomyocyte apoptosis. In vitro, ALK4 haploinsufficiency blocked the cellular proliferation/differentiation and collagen production in cultured cardiac fibroblasts after angiotensin-II stimulation. Mechanistically, ALK4 haploinsufficiency resulted in the suppression of Smad2/3 activity. CONCLUSION: Our results demonstrate that ALK4 haploinsufficiency ameliorates cardiac fibrosis and dysfunction in a mouse pressure-overload model associated with inhibition of cardiac fibroblast activation and cardiomyocyte apoptosis through the suppression of Smad2/3 activity, and suggest that ALK4 is a novel therapeutic target in treating pressure overload-induced cardiac remodeling and heart failure.

Besides an ITIM/SHP-1-dependent pathway, CD22 collaborates with Grb2 and plasma membrane calcium-ATPase in an ITIM/SHP-1-independent pathway of attenuation of Ca2+i signal in B cells.

CD22 is a surface immunoglobulin implicated in negative regulation of B cell receptor (BCR) signaling; particularly inhibiting intracellular Ca2+ (Ca2+i)signals. Its cytoplasmic tail contains six tyrosine residues (Y773/Y783/Y817/Y828/Y843/Y863, designated Y1~Y6 respectively), including three (Y2/5/6) lying within immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that serve to recruit the protein tyrosine phosphatase SHP-1 after BCR activation-induced phosphorylation. The mechanism of inhibiting Ca2+i by CD22 has been poorly understood. Previous study demonstrated that CD22 associated with plasma membrane calcium-ATPase (PMCA) and enhanced its activity (Chen, J. et al. Nat Immunol 2004;5:651-7). The association is dependent on BCR activation-induced cytoplasmic tyrosine phosphorylation, because CD22 with either all six tyrosines mutated to phenylalanines or cytoplasmic tail truncated loses its ability to associate with PMCA. However, which individual or a group of tyrosine residues determine the association and how CD22 and PMCA interacts, are still unclear. In this study, by using a series of CD22 tyrosine mutants, we found that ITIM Y2/5/6 accounts for 34.3~37.1% Ca2+i inhibition but is irrelevant for CD22/PMCA association. Non-ITIM Y4 and its YEND motif contribute to the remaining 69.4~71.7% Ca2+i inhibition and is the binding site for PMCA-associated Grb2. Grb2, independently of BCR cross-linking, is constitutively associated with and directly binds to PMCA in both chicken and human B cells. Knockout of Grb2 by CRISPR/Cas9 completely disrupted the CD22/PMCA association. Thus, our results demonstrate for the first time that in addition to previously-identified ITIM/SHP-1-dependent pathway, CD22 holds a major pathway of negative regulation of Ca2+i signal, which is ITIM/SHP-1-independent, but Y4/Grb2/PMCA-dependent.

Rac1b enhances cell survival through activation of the JNK2/c-JUN/Cyclin-D1 and AKT2/MCL1 pathways.

Rac1b is a constitutively activated, alternatively spliced form of the small GTPase Rac1. Previous studies showed that Rac1b promotes cell proliferation and inhibits apoptosis. In the present study, we used microarray analysis to detect genes differentially expressed in HEK293T cells and SW480 human colon cancer cells stably overexpressing Rac1b. We found that the pro-proliferation genes JNK2, c-JUN and cyclin-D1 as well as anti-apoptotic AKT2 and MCL1 were all upregulated in both lines. Rac1b promoted cell proliferation and inhibited apoptosis by activating the JNK2/c-JUN/cyclin-D1 and AKT2/MCL1 pathways, respectively. Very low Rac1b levels were detected in the colonic epithelium of wild-type Sprague-Dawley rats. Knockout of the rat Rac1 gene exon-3b or knockdown of endogenous Rac1b in HT29 human colon cancer cells downregulated only the AKT2/MCL1 pathway. Our study revealed that very low levels of endogenous Rac1b inhibit apoptosis, while Rac1b upregulation both promotes cell proliferation and inhibits apoptosis. It is likely the AKT2/MCL1 pathway is more sensitive to Rac1b regulation.

Dual-specificity phosphatase 14 protects the heart from aortic banding-induced cardiac hypertrophy and dysfunction through inactivation of TAK1-P38MAPK/-JNK1/2 signaling pathway.

Dual-specificity phosphatase 14 (Dusp14), an important negative modulator of mitogen-activated protein kinase (MAPK) signaling pathways, has been implicated in inflammatory immune response, cancers, cell differentiation and proliferation. The role of Dusp14 in chronic pressure overload-induced cardiac hypertrophy has not been explored. Here we have shown that Dusp14-/- knockout mice and cardiac-specific Dusp14 transgenic mice were generated and subjected to aortic banding (AB) for 4 weeks. Our results demonstrated that genetic loss of Dusp14 significantly aggravated cardiac hypertrophy, fibrosis, ventricular dilation and dysfunction, whereas transgenic cardiac-specific Dusp14 overexpression significantly attenuated AB-induced cardiac dysfunction and remodeling. In vitro, adenoviral overexpression of constitutive Dusp14 blocked angiotensin II-induced hypertrophic growth of cardiomyocytes, while Dusp14 knockdown led to opposite effects. Mechanistically, excessive phosphorylation of TAK1, P38MAPK and JNK1/2 was evidenced in Dusp14-/- knockout mice post-AB and inactivation of TAK1-P38MAPK and -JNK1/2 signaling using TAK1 inhibitor 5Z-7-ox shares similar antihypertrophic effect as Dusp14 overexpression. Moreover, we show that Dusp14 directly interacted with TAK1. Results from present experiments indicate that Dusp14 protects the heart from AB-induced cardiac hypertrophy and dysfunction possibly through inactivation of TAK1-P38MAPK/-JNK1/2 signaling pathway. Future studies are warranted to test the feasibility of overexpressing Dusp14 as a therapeutic strategy to attenuate cardiac hypertrophy and failure.

Semaphorin 3a transfection into the left stellate ganglion reduces susceptibility to ventricular arrhythmias after myocardial infarction in rats.

AIMS: Myocardial infarction (MI) induces neural remodelling of the left stellate ganglion (LSG), which may contribute to ischaemia-induced arrhythmias. The neural chemorepellent Semaphorin 3a (Sema3a) has been identified as a negative regulator of sympathetic innervation in the LSG and heart. We previously reported that overexpression of Sema3a in the border zone could reduce the arrhythmogenic effects of cardiac sympathetic hyperinnervation post-MI. This study investigated whether Sema3a overexpression within the LSG confers an antiarrhythmic effect after MI through decreasing extra- and intra-cardiac neural remodelling. METHODS AND RESULTS: Sprague-Dawley rats were subjected to MI, and randomly allocated to intra-LSG microinjection of either phosphate-buffered saline (PBS), adenovirus encoding green fluorescent protein (AdGFP), or adenovirus encoding Sema3a (AdSema3a). Sham-operated rats served as controls. Two weeks after infarction, MI-induced nerve sprouting and sympathetic hyperinnervation in the LSG and myocardium were significantly attenuated by intra-LSG injection with AdSema3a, as assessed by immunohistochemistry and western blot analysis of growth-associated protein 43 and tyrosine hydroxylase. This was also confirmed by sympathetic nerve function changes assessed by cardiac norepinephrine content. Additionally, intra-LSG injection with AdSema3a alleviated MI-induced accumulation of dephosphorylated connexin 43 in the infarct border zone. Furthermore, Sema3a overexpression in the LSG reduced the incidence of inducible ventricular tachyarrhythmia by programmed electrical stimulation post-MI, and arrhythmia scores were significantly lower in the AdSema3a group than in the PBS and AdGFP groups. CONCLUSION: Semaphorin 3a overexpression in the LSG ameliorates the inducibility of ventricular arrhythmias after MI, mainly through attenuation of neural remodelling within the cardiac-neuraxis.

Effect of the angiotensin II receptor blocker valsartan on cardiac hypertrophy and myocardial histone deacetylase expression in rats with aortic constriction.

The aim of the present study was to observe the myocardial expression of members of the histone deacetylase (HDAC) family (HDAC2, HDAC5 and HDAC9) in rats with or without myocardial hypertrophy (MH) in the presence and absence of the angiotensin II receptor blocker valsartan. Adult male Wistar rats were randomly divided into three groups (n=6/group): Sham-operated control rats, treated with distilled water (1 ml/day) through gavage; rats with MH (established through aortic constriction), treated with distilled water (1 ml/day) through gavage; and MH + valsartan rats, treated with 20 mg/kg/day valsartan through gavage. Treatments commenced one day after surgery and continued for eight weeks. Body weight (BW), heart weight (HW) and plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels were determined, and the myocardial expression of HDAC2, HDAC5 and HDAC9 was analyzed through a reverse transcription semi-quantitative polymerase chain reaction. The BWs of the rats in the three groups were similar at baseline; however, after eight weeks the BW of the rats in the MH + valsartan group was significantly reduced compared with that of the MH rats. Furthermore, the HW/BW ratio and plasma ANP and BNP levels were increased, the myocardial HDAC2 expression was significantly upregulated and the HDAC5 and HDAC9 expression was significantly downregulated in the MH rats compared with those in the control rats; however, these changes were significantly attenuated by valsartan. Modulation of myocardial HDAC5, HDAC9 and HDAC2 expression may therefore be one of the anti-hypertrophic mechanisms of valsartan in this rat MH model.

Sanguinarine inhibits Rac1b-rendered cell survival enhancement by promoting apoptosis and blocking proliferation.

AIM: Small GTPase Rac1 is a member of the Ras superfamily, which plays important roles in regulation of cytoskeleton reorganization, cell growth, proliferation, migration, etc. The aim of this study was to determine how a constitutively active Rac1b regulated cell proliferation and to investigate the effects of the Rac1b inhibitor sanguinarine. METHODS: Three HEK293T cell lines stably overexpressing GFP, Rac1-GFP or Rac1b-GFP were constructed by lentiviral infection. The cells were treated with sanguinarine (1 µmol/L) or its analogue berberine (1 µmol/L) for 4 d. Cell proliferation was evaluated by counting cell numbers and with a BrdU incorporation assay. The levels of cleaved PARP-89 (an apoptosis marker) and cyclin-D1 (a proliferative index) were measured using Western blotting. RESULTS: In 10% serum-containing media, overexpressing either Rac1 or Rac1b did not significantly change the cell proliferation. In the serum-starved media, however, the survival rate of Rac1b cells was significantly increased, whereas that of Rac1 cells was moderately increased. The level of cleaved PARP-89 was significantly increased in serum-starved Rac1 cells, but markedly reduced in serum-starved Rac1b cells. The level of cyclin-D1 was significantly increased in both serum-starved Rac1 and Rac1b cells. Treatment with sanguinarine, but not berberine, inhibited the proliferation of Rac1b cells, which was accompanied by significantly increased the level of PARP-89, and decreased both the level of cyclin-D1 and the percentage of BrdU positive cells. CONCLUSION: Rac1b enhances the cell proliferation under a growth-limiting condition via both anti-apoptotic and pro-proliferative mechanisms. Sanguinarine, as the specific inhibitor of Rac1b, is a potential therapeutic agent for malignant tumors with up-regulated Rac1b.