The mechanism of Rap1GAP in ventricular hypertrophy and interstitial fibrosis induced by angiotensin Ⅱ

In the myocardium, collagen fibers provide a supporting framework for myocytes and blood vessels and act as lateral connections between muscle bundles. These functional properties of collagen serve to maintain tissue architecture and to coordinate the delivery of force generated by myocytes on the ventricular chamber. The accumulation of excess collagen is believed to be an important pathophysiological process that contributes to diastolic heart failure. Diastolic heart failure accounts for 30% to 50% of heart failure in clinical practice, and hypertensive disease is the major cause of this type of heart failure.1 The precise mechanisms responsible for excess fibrillar collagen accumulation in the pathological heart are poorly understood. Fibrosis of both the injured and noninjured myocardium2 indicates that humoral mechanisms are responsible for this process. In the failing heart, several humoral, autocrine, and paracrine systems are activated,3 suggesting that cross-talk between synergistic and opposing signaling pathways constitutes the predominant form of regulation under these conditions. Several factors have been identified as potentially important mediators of cardiac collagen production. In vitro studies of neonatal and adult rat cardiac fibroblasts have shown that angiotensin II (Ang II) directly stimulates cardiac fibroblast proliferation and collagen synthesis via Ang II type 1 (AT1) receptors.4 5 6 In this issue of Hypertension , Pathak et al7 provided evidence that a myocyte cofactor was an important mediator of Ang II–induced collagen type I and type III mRNA synthesis in a rat cell coculture model. This work, together with other studies, provides strong evidence that Ang II indirectly regulates cardiac fibroblast function via specific growth factors.8 9 10 11 12 13 14 15 16 17 18 19 20 21 Although the primary autocrine and paracrine mediators of Ang II effects on fibrillar collagen synthesis remain to be elucidated, principal candidates …

Objective To investigate the role of α7 nicotinic acetylcholine receptor (α7nAchR) agonist in myocardial fibrosis and its possible mechanism. Methods The cardiac fibroblasts were isolated and cultured from neonatal rats. The cardiac fibroblasts were divided into the following four groups: blank control group (cardiac fibroblasts without any intervention); model group [cardiac fibroblasts treated with 10-6 mol/L angiotensin Ⅱ (Ang Ⅱ) only]; α7nAchR agonist group (cardiac fibroblasts treated with 5×10-6 mol/L PNU-282987, and 1 h later treated with 10-6 mol/L Ang Ⅱ); α7nAchR antagonist group (cardiac fibroblasts treated with 10-6 mol/L MLA, and 1 h later treated with 10-6 mol/L Ang Ⅱ). The proliferation abilities of cardiac fibroblasts in different treatment groups were measured using WST-1 method. The expression levels of α7nAchR genes in cardiac fibroblasts in different treatment groups were examined by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR). The expression levels of α7nAchR, type Ⅰ and type Ⅲ collagen, α-smooth muscle actin (α-SMA), p38 mitogen activated protein kinase (p38MAPK) and phosphorylated p38MAPK (p-p38MAPK) proteins in cardiac fibroblasts were detected by Western blotting. Results (1) The final absorbance in the α7nAchR agonist group (0.50±0.13) was significantly lower than α7nAchR antagonist group and model group (0.75±0.10, 0.63±0.11, F=10.567, P=0.000). It suggested that activation of α7nAchR could inhibit the proliferation of cardiac fibroblasts. (2) The relative expression levels of α7nAchR mRNA and protein in α7nAchR agonist group (0.87±0.15, 0.76±0.08) were significantly higher than the α7nAchR antagonist group (0.45±0.09, 0.40±0.14), model group (0.62±0.11, 0.59±0.10) and blank control group (0.32±0.13, 0.30±0.07, F=25.402, P=0.000). It suggested that α7nAchR agonists can upregulate the expression of α7nAchR gene in cardiac fibroblasts. (3) The relative expression levels of type Ⅰ and type Ⅲ collagen proteins, α-SMA protein and p-p38MAPK protein in α7nAchR agonist group (0.53±0.09, 0.50±0.12, 0.38±0.08, 0.27±0.09) were lower than the model group (0.65±0.12, 0.62±0.10, 0.57±0.11, 0.45±0.11) and α7nAchR antagonist group (0.81±0.13, 0.71±0.11, 0.70±0.10, 0.68±0.08), while were higher than the blank control group (0.41±0.08, 0.35±0.06, 0.19±0.07, 0.16±0.07, F=29.647, 32.962, 30.549, 53.665, P=0.000, 0.000, 0.000, 0.000). The relative expression of p38MAPK protein in the α7nAchR agonist group (0.71±0.12) was higher than the model group (0.52±0.10) and α7nAchR antagonist group (0.35 ± 0.09), but was lower than the blank control group (0.85 ± 0.14, F=44.347, P=0.000). Conclusion α7nAchR agonists could inhibit the proliferation of cardiac fibroblasts and reduce the synthesis of collagen between cells. The mechanism might be related to inhibition of p38MAPK signaling pathway activation. Key words: Cardiac fibroblasts; α 7 nicotinic acetylcholine receptor agonist; Fibrosis; p38 mitogen-activated protein kinase signaling pathway

Velvet antler peptide prevents pressure overload-induced cardiac fibrosis via transforming growth factor (TGF)-β1 pathway inhibition

β-glucan improves intestinal health of pearl gentian grouper via activation of the p38 mitogen-activated protein kinase signaling pathway

BackgroundHeart failure (HF) is often accompanied by cardiac fibrosis, a pathological process driven by activated cardiac fibroblasts (CFs) transitioning to a myofibroblast phenotype. The Runt-related transcription factor 1 (Runx1) has been implicated in various fibrotic diseases, but its role in cardiac fibrosis and HF progression remains unclear. This study aimed to elucidate the role of Runx1 in CF activation, cardiac fibrosis, and HF development.MethodsHF was induced in mice using transverse aortic constriction (TAC). Runx1 expression was assessed in failing hearts via Western blot and qPCR, with immunostaining to localize Runx1 in CFs. In vitro, CFs were treated with TGF-β, and Runx1 knockdown was achieved using siRNA or adenoviral-mediated deletion. Myofibroblast-specific Runx1 knockout mice (PostnCre, Runx1F/F) were used to investigate the in vivo effects of Runx1 on cardiac function, fibrosis, and hypertrophy post-TAC. Chromatin immunoprecipitation (ChIP) and luciferase assays were conducted to evaluate Runx1’s regulation of Postn transcription.ResultsTAC-induced HF was associated with significant upregulation of Runx1 protein and mRNA levels, particularly in CFs. In vitro, Runx1 knockdown suppressed TGF-β-induced markers of CF activation, including α-smooth muscle actin (α-SMA), periostin (Postn), and collagen type I (Col1a1), and reduced CF migration and proliferation. PostnCre-Runx1F/F mice exhibited improved cardiac function, reduced hypertrophy, and decreased fibrosis compared to control mice post-TAC. Mechanistically, Runx1 was found to bind the Postn promoter and recruit the transcriptional coactivator P300, enhancing histone acetylation and promoting Postn transcription.ConclusionsRunx1 plays a pivotal role in cardiac fibroblast activation and fibrosis, likely through epigenetic regulation of Postn expression, thereby driving heart failure progression. Targeting Runx1 may represent a promising therapeutic strategy for heart failure.

O6. Effect of mechanical stimulation and indomethacin on cancellous bone formation in rat tail vertebrae

P1. Bone formation in vivo by cultured human marrow stromal and trabecular bone-derived cells

Selenium (Se) is considered to have antioxidant properties, which are beneficial for heart condition. Hyperhomocysteinemia (HHCY) has been suggested to potentially lead to heart failure and is characterized by cardiac fibrosis; however, investigation on the role of Se and HHCY in cardiac fibrosis is rare. Since previous studies demonstrated the important role of the long non-coding RNA maternally expressed 3 (MEG3) in some heart diseases, the present study aimed to determine how Se and MEG3 might exert regulatory effects on HCY-induced fibrosis in cardiac fibroblasts (CFs). Mouse CFs were isolated and treated with HCY and Se. The expression of α-smooth muscle actin (α-SMA), collagen I and III was detected by western blotting to reflect CF fibrosis. Reverse transcription-quantitative PCR was performed to determine the expression levels of MEG3. Inflammation and oxidative stress responses were analyzed by measuring TNF-α, IL-1β (ELISA) and reactive oxygen species levels (using a commercial kit), respectively. Cell Counting Kit-8 was used to evaluate CF proliferation. Total and phosphorylated (p) expression of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) was evaluated by western blotting. CFs were transfected with adenovirus expressing MEG3 short-hairpin RNA to knock down MEG3 expression. Se treatment downregulated the expression level of MEG3 in HCY-stimulated CFs, whilst inhibiting the inflammatory and oxidative stress response. Furthermore, Se inhibited the increased proliferation of CFs following HCY treatment. In addition, MEG3-knockdown in CFs could improve fibrosis caused by HCY. Furthermore, the ratios of p-JAK2/JAK2 and p-STAT3/STAT3 were decreased following treatment with Se or MEG3 silencing. Taken together, the findings from the present study suggested that Se may alleviate cardiac fibrosis by downregulating the expression of MEG3 and reducing the inflammatory and oxidative stress response in CFs. This suggests that Se may be a potential therapeutic option for treating cardiac fibrosis in the future.

Long-term diabetes can cause many serious complications. It is generally accepted that diabetes results in the development of diabetic cardiomyopathy independent of hypertension and coronary heart disease. Cardiac fibrosis is...

Background/AimsPancreatic ductal adenocarcinoma (PDAC) is a challenging cancer to treat and has a poor prognosis and limited treatment options. In this study, the anticancer effects of disulfiram combined with copper (DSF/Cu) on PDAC cells, including those resistant to 5-fluorouracil, was assessed.MethodsHuman pancreatic cancer cells (BxPC-3 and CFPAC-1) and their 5-fluorouracil-resistant (5FUR) counterparts were treated with DSF/Cu to assess cytotoxicity. Expression levels of nuclear factor E2-related factor-2 (NRF-2) and heme oxygenase-1 (HO-1) were analyzed by reverse transcription quantitative polymerase chain reaction and Western blotting, while intracellular reactive oxygen species (ROS) levels were evaluated using H2DCFDA staining and flow cytometry. The effects of DSF/Cu on protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) signaling pathways were evaluated by Western blot analysis. In vivo efficacy was investigated using a xenograft mouse model, in which mice were orally administered DSF (75 mg/kg) and Cu (2 mg/kg) twice weekly for 5 weeks.ResultsWe demonstrated that DSF/Cu effectively induced cytotoxicity in both pancreatic cancer cells and their 5FUR counterparts by modulating ROS levels, NRF-2 levels, and associated survival pathways. DSF/Cu treatment significantly decreased NRF-2 expression and reduced ROS levels, specifically in 5FUR cells. DSF/Cu facilitated NRF-2-independent HO-1 expression and differentially modulated Akt and MAPK signaling pathways in pancreatic cancer cells and their 5FUR counterparts. In vivo studies using a xenograft mouse model confirmed the antitumor efficacy of DSF/Cu, as evidenced by reduced tumor volumes and NRF-2 expression.ConclusionsThese findings highlight the potential of DSF/Cu as a novel and effective therapeutic strategy for PDAC, specifically for overcoming resistance to standard therapies.

Curcumin (Cur) has been reported to function as an antioxidant and anti-inflammatory agent and to play a role in anti-atherosclerosis. The present study aimed to explore the protective effect of Cur on hypoxia/reoxygenation (H/R) injury. The morphological changes in H9c2 cardiomyocytes were observed under an inverted microscope. Cell viability was determined by Cell Counting Kit-8 (CCK-8). Lactate dehydrogenase (LDH) level, malondialdehyde (MDA) level and the antioxidant superoxide dismutase (SOD) activity were determined by corresponding kits. Apoptosis and reactive oxygen species (ROS) levels were determined by flow cytometry. Endoplasmic reticulum (ER) stress-related factors, which were examined by quantitative real-time polymerase chain reaction (qPCR) and western blot analysis, included 78-kDa glucose-regulated protein (GRP78) and C/EBP homologous protein (CHOP). Extracellular signal regulating kinase 1/2 (ERK1/2), p38, c-Jun NH2-terminal kinase (JNK) and the phosphorylation levels of key proteins in the mitogen-activated protein kinase (MAPK) signaling pathway were all determined by western blot analysis. Compared to the control group, the cell morphology of the H9c2 cells was obviously altered upon H/R. Cell viability was significantly decreased, while apoptosis was significantly increased by H/R. We also observed that the levels of LDH and MDA were elevated and the activity of SOD was decreased in the H/R group. Notably, LDH, MDA and SOD levels were reversed following treatment with Cur; while apoptosis and ROS levels in the H/R injury group were decreased by Cur. H/R injury-triggered ER stress and the MAPK signaling pathway were suppressed by Cur. These results demonstrated that Cur has a protective effect on cardiomyocytes via suppression of ER stress and the MAPK pathway.

Basigin Promotes Cardiac Fibrosis and Failure in Response to Chronic Pressure-Overload in Mice

Cardiac fibrosis is an important pathological feature of cardiac remodeling in heart diseases. Methyl-CpG-binding protein 2 (MeCP2) is a transcription inhibitor, and plays a key role in the fibrotic diseases. However, the precise role of MeCP2 in cardiac fibrosis remains unclear. α-tubulin plays an essential role in cell function, whereby the acetylation state of α-Tubulin dictates the efficiency of cell proliferation and differentiation. This study was undertaken to investigate that MeCP2 dynamics affect the acetylation state of α-tubulin in the cardiac fibrosis. Forty adult male Sprague-Dawley (SD) rats were randomly divided into two groups, cardiac fibrosis was produced by common ISO. Cardiac fibroblasts (CFs) were harvested from SD neonate rats and cultured. The expression of HDAC6, MeCP2, α-SMA, collagen I was measured by western blotting and qRT-PCR. siRNA of HDAC6 and MeCP2 effect the proliferation of cardiac fibroblasts, and affect the acetylation state of α-tubulin. We have found the acetylation state of α-tubulin in cardiac fibroblasts as well as cardiac tissue from a ISO-induced rat cardiac fibrosis model and observed a reduction in acetylated α-tubulin and an increase in the α-tubulin-specific deacetylase, histone deacetylase 6 (HDAC6). Furthermore, we have shown that treatment of cardiac fibroblasts with HDAC6 inhibitor Tubastatin A and HDAC6-siRNA can restore α-tubulin acetylation levels. In addition, treatment of cardiac fibroblasts with MeCP2-siRNA blocked cell proliferation. Knockdown of MeCP2 suppresses HDAC6 expression in activated cardiac fibroblasts but increases the acetylation of α-tubulin. We demonstrated that MeCP2 may negatively control the acetylation of α-tubulin through HDAC6 in cardiac fibroblast proliferation and fibrosis. This study indicated that MeCP2 could be a potentially new therapeutic option for cardiac fibrosis.

The vicious cycle of arrhythmia and myocardial fibrosis.

Dynamic and Temporal Transcriptomic Analysis Reveals Ferroptosis-Mediated Antileukemia Activity of S-Dimethylarsino-Glutathione: Insights into Novel Therapeutic Strategy