Lysine demethylase 5B transcriptionally regulates TREM1 in human cardiac fibroblasts

Background:A differential gene,triggering receptor expressed on myeloid cells 1(TREM1),was identified in blood sequencing datasets from myocardial infarction patients and healthy controls.Myocardialfibrosis following myocardial infarction significantly contributes to cardiac dysfunction.Objectives:This study aimed to unveil the intrinsic regulatory mechanism of TREM1 in myocardialfibrosis.Methods:Mimicking pathology by angiotensin II(Ang II)treatment of human cardiacfibroblasts(HCFs),the impacts of TREM1 knockdown on its proliferation,migration,and secretion of the pro-fibrotic matrix were identified.Using the Human Transcription Factor Database(HumanTFDB)website,lysine-specific demethylase 5B(KDM5B)was found to bind to the TREM1 promoter,which was further validated through luciferase reporter and chromatin immunoprecipitation(ChIP).By promoting KDM5B overexpression,its effect on the regulation of TREM1 was examined.Results:TREM1 knockdown suppressed the proliferation,migration,and secretion of the pro-fibrotic matrix in HCFs upon Ang II treatment.KDM5B bound to the TREM1 promoter and upregulated its transcriptional expression.Furthermore,KDM5B overexpression reversed the regulation of the above cellular phenotypes by TREM1 knockdown.Conclusion:This study sheds light on the positive regulation of TREM1 by KDM5B,demonstrating their role in promoting myocardialfibrosis.Thisfinding provides a theoretical foundation for understanding disease pathology and potentially advancing the development of new targeted therapies.

Calcitriol Suppressed Isoproterenol-induced Proliferation of Cardiac Fibroblasts via Integrinβ3/FAK/Akt Pathway

Objective Cardiac fibroblasts(CFs)proliferation and extracellular matrix deposition are important features of cardiac fibrosis.Various studies have indicated that vitamin D displays an anti-fibrotic property in chronic heart diseases.This study explored the role of vitamin D in the growth of CFs via an integrin signaling pathway.Methods MTT and 5-ethynyl-2′-deoxyuridine assays were performed to determine cell viability.Western blotting was performed to detect the expression of proliferating cell nuclear antigen(PCNA)and integrin signaling pathway.The fibronectin was observed by ELISA.Immunohistochemical staining was employed to evaluate the expression of integrinβ3.Results The PCNA expression in the CFs was enhanced after isoproterenol(ISO)stimulation accompanied by an elevated expression of integrin beta-3(β3).The blockade of the integrinβ3 with a specific integrinβ3 antibody reduced the PCNA expression induced by the ISO.Decreasing the integrinβ3 by siRNA reduced the ISO-triggered phosphorylation of FAK and Akt.Both the FAK inhibitor and Akt inhibitor suppressed the PCNA expression induced by the ISO in the CFs.Calcitriol(CAL),an active form of vitamin D,attenuated the ISO-induced CFs proliferation by downregulating the integrinβ3 expression,and phosphorylation of FAK and Akt.Moreover,CAL reduced the increased levels of fibronectin and hydroxyproline in the CFs culture medium triggered by the ISO.The administration of calcitriol decreased the integrinβ3 expression in the ISO-induced myocardial injury model.Conclusion These findings revealed a novel role for CAL in suppressing the CFs growth by the downregulation of the integrinβ3/FAK/Akt pathway.

Effect of aldosterone on the proliferation of rat cardiac fibroblasts

Objective:A cell model of cardiac fibroblasts proliferation induced by aldosterone was established to observe the effect of aldosterone on the proliferation of rat cardiac fibroblasts.Methods:Primary cardiac fibroblasts were cultured by trypsin digestion method and differential adhesion method,primary cardiac fibroblasts were sub-cultured by conventional digestion method,and the immunocytochemical assay was used to identify cardiac fibroblasts.The second-generation cardiac fibroblasts were randomly divided into five groups:standard control group,10-9 mol/L aldosterone(ALD1)group,10-8 mol/L aldosterone(ALD2)group,10-7 mol/L aldosterone(ALD3)group,and 10-6 mol/L aldosterone(ALD4)group.The viability of fibroblast cells in each group was detected by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.Results:Vimentin staining assay showed that the cultured cells staining positive,and the purity of cultured mouse cardiac fibroblasts was 95%.The results of methyl thiazolyl tetrazolium showed that compared with the control group,the low concentration of aldosterone(10-9 mol/L)had no significant effect on the proliferation of normal cardiac fibroblasts.With the increase in the intensity of(10-8–10-6)mol/L,aldosterone could significantly promote the proliferation of cardiac fibroblasts.Moreover,there was no significant difference in absorbance value between the aldosterone group(10-6 mol/L)and the aldosterone group(10-7 mol/L)(P>0.05).The highest concentration of aldosterone group 10-7 mol/L promoted the proliferation of cardiac the optimum concentration was 10-7 mol/L.Conclusion:Aldosterone can promote the spread of cardiac fibroblasts in a specific concentration range.

Effects of Paeonol on Expression of Type Ⅰ and Type Ⅲ Collagen of High Glucose Induced Proliferation of Cardiac Fibroblasts

[Objectives]To explore the effects of paeonol on the inhibition of myocardial fibrosis in high glucose induced cardiac fibroblasts(CFs).[Methods]Differential adherence method was used to culture the primary CFs of neonatal rats(passage culture);CCK-8 method was used to detect the cell proliferation;MTT assay was used to screen the safe concentration of paeonol;the 2 nd to 3 rd generation CFs were randomly divided into normal group(5.5 mmol/L,expressed in C),high glucose group(30 mmol/L,expressed in HG),paeonol low dose group(Pae-L,17.5 mg/L),and medium dose paeonol group(Pae-M,35 mg/L),paeonol high dose group(Pae-H,70 mg/L);Western Blot method was used to detect the expression of Col-I and Col-III protein.[Results]The extraction of CFs from primary neonatal rats was successful;high glucose(30 mmol/L)induction had a significant proliferation effect on CFs;compared with the normal group,the expressions of COI-I and Col-III protein were increased in the high glucose group(P<0.05);compared with the high glucose group,the expression of COI-I protein was decreased in each treatment group(P<0.05,P<0.01),and the decrease was most significant in the high dose group(P<0.01);the expression of COI-III in the high dose group was decreased and it was statistically significant(P<0.05).[Conclusions]Paeonol significantly inhibited the proliferation of high glucose induced CFs in neonatal rats.This experiment is intended to provide a new experimental basis for the prevention and treatment of diabetic cardiomyopathy(DCM).

Hydrogen sulfide suppresses transforming growth factor-β1-induced differentiation of human cardiac fibroblasts into myofibroblasts

In heart disease, transforming growth factor-β1 （TGF-β1） converts fibroblasts into myofibroblasts, which synthesize and se- crete fibrillar type I and III collagens. The purpose of the present study was to investigate how hydrogen sulfide （HzS） sup- presses TGF-~l-induced differentiation of human cardiac fibroblasts to myofibroblasts. Human cardiac fibroblasts were se- rum-starved in fibroblast medium for 16 h before exposure to TGF-β1 （10 ng mL-1） for 24 h with or without sodium hydrosul- fide （NariS, 100 μmol L-1, 30 min pretreatment） treatment. NariS, an exogenous HzS donor, potently inhibited the prolifera- tion and migration of TGF-β1-induced human cardiac fibroblasts and regulated their cell cycle progression. Furthermore, NariS treatment led to suppression of fibroblast differentiation into myofibroblasts, and reduced the levels of collagen, TGF-β1, and activated Smad3 in TGF-β1-induced human cardiac fibroblasts in vitro. We therefore conclude that H2S sup- presses TGF-β1-stimulated conversion of fibroblasts to myofibroblasts by inhibiting the TGF-β1/Smad3 signaling pathway, as well as by inhibiting the proliferation, migration, and cell cycle progression of human cardiac myofibroblasts. These effects of H2S may play significant roles in cardiac remodeling associated with heart failure.

Sodium tanshinone ⅡA sulfonate prevents radiation-induced damage in primary rat cardiac fibroblasts

This study investigated the effects of X-ray irradiation on primary rat cardiac fibroblasts(CFs) and its potential mechanism, as well as whether sodium tanshinone ⅡA sulfonate(STS) has protective effect on CFs and its possible mechanism. Our data demonstrated that X-rays inhibited cell growth and increased oxidative stress in CFs, and STS mitigated X-ray-induced injury. Enzyme-linked immuno-sorbent assay showed that X-rays increased the levels of secreted angiotensin Ⅱ(Ang Ⅱ) and brain natriuretic peptide(BNP). STS inhibited the X-ray-induced increases in Ang Ⅱ and BNP release. Apoptosis and cell cycle of CFs were analyzed using flow cytometry. X-rays induced apoptosis in CFs, whereas STS inhibited apoptosis in CFs after X-ray irradiation. X-rays induced S-phase cell cycle arrest in CFs, which could be reversed by STS. X-rays increased the expression of phosphorylated-P38/P38,cleaved caspase-3 and caspase-3 as well as decreased the expression of phosphorylated extracellular signal-regulated kinase 1/2(ERK1/2)/ERK 1/2 and B cell lymphoma 2(Bcl-2)/Bcl-2 associated X protein(BAX) in CFs, as shown by Western blotting. STS mitigated the X-ray radiation-induced expression changes of these proteins. In conclusion, our results demonstrated that STS may potentially be developed as a medical countermeasure to mitigate radiation-induced cardiac damage.

Compensatory function of bradykinin B1 receptor in the inhibitory effect of captopril on cardiomyocyte hypertrophy and cardiac fibroblast proliferation in neonatal rats

Background Bradykinin （BK） acts mainly on two receptor subtypes： B1 and B2, and activation of B2 receptor mediates the most well-known cardioprotective effects of angiotensin converting enzyme inhibitors （ACEi）, however, the role that B1 receptor plays in ACEi has not been fully defined. We examined the role of B1 receptor in the inhibitory effect of ACE inhibitor captopril on rat cardiomyocyte hypertrophy and cardiac fibroblast proliferation induced by angiotensin Ⅱ （Ang Ⅱ） and explored its possible mechanism. Methods Neonatal cardiomyocytes and cardiac fibroblasts （CFs） were randomly treated with Ang Ⅱ, captopdl, B2 receptor antagonist （HOE-140） and B1 receptor antagonist （des-Arg^10, Leu^9-kallidin） alone or in combination. Flow cytometry was used to evaluate cell cycle, size and protein content. Nitric oxide （NO） and intracellular cyclic guanosine monophosphate （cGMP） level were measured by colorimetry and radioimmunoassay. Results After the CFs and cardiomyocytes were incubated with 0.1 μmol/L Ang Ⅱ for 48 hours, the percentage of CFs in the S stage, cardiomyocytes size and protein content significantly increased （both P 〈0.01 vs control）, and these increases were inhibited by 10 μmol/L captopril. However, NO and cGMP levels were significantly higher than that with Ang Ⅱ alone （both P 〈0.01）. 1 μmol/L HOE-140 or 0.1 pmol/L des-Arg^10, Leu^9-kallidin attenuated the effects of captopril, which was blunted further by blockade of both B1 and B2 receptors. Conclusions Acting via B2 receptor, BK contributes to the antihypertrophic and antiproliferative effects of captopril on cardiomyocytes and CFs. In the absence of B2 receptor, B1 receptor may act a compensatory mechanism for the B2 receptor and contribute to the inhibition of cardiomyocyte hypertrophy and CFs proliferation by captopril. NO and cGMP play an important role in the effect of B1 receptor.

Cardiac Fibroblast-Specific Activating Transcription Factor 3 Promotes Myocardial Repair after Myocardial Infarction

Background：Myocardial ischemia injury is one of the leading causes of death and disability worldwide.Cardiac fibroblasts （CFs） have central roles in modulating cardiac function under pathophysiological conditions.Activating transcription factor 3 （ATF3） plays a self-protective role in counteracting CF dysfunction.However,the precise function of CF-specific ATF3 during myocardial infarction （MI） injury/repair remains incompletely understood.The aim of this study was to determine whether CF-specific ATF3 affected cardiac repair after MI.Methods：Fifteen male C57BL/6 wild-type mice were performed with MI operation to observe the expression of ATF3 at 0,0.5,1.0,3.0,and 7.0 days postoperation.Model for MI was constructed in ATF3TGfl/flColla2-Cre＋ （CF-specific ATF3 overexpression group,n =5） and ATF3TGfl/flColla2-Cre-male mice （without CF-specific ATF3 overexpression group,n =5）.In addition,five mice of ATF3TGfl/flCol1a2-Cre＋ and ATF3TGfl/flCol 1 a2-Cre-were subjected to sham MI operation.Heart function was detected by ultrasound and left ventricular remodeling was observed by Masson staining （myocardial fibrosis area was detected by blue collagen deposition area） at the 28th day after MI surgery in ATF3TGfl/flColla2-Cre＋ and ATF3TGfl/flColla2-Cre-mice received sham or MI operation.Quantitative real-time polymerase chain reaction （qRT-PCR） was used to detect cell proliferation/cell cycle-related gene expression in cardiac tissue.BrdU staining was used to detect fibroblast proliferation.Results：After establishment of an MI model,we found that ATF3 proteins were increased in the heart of mice after MI surgery and dominantly expressed in CFs.Genetic overexpression of ATF3 in CFs （ATF3TGfl/flCol1a2-Cre＋ group） resulted in an improvement in the heart function as indicated by increased cardiac ejection fraction （41.0% vs.30.5%,t =8.610,P =0.001） and increased fractional shortening （26.8% vs.18.1%,t =7.173,P =0.002）,which was accompanied by a decrease in cardiac scar area （23.1% vs.11.0%,t =8.610,P =0.001）.qRT-PCR analysis of CFs isolated from ATF3TGfl/flCol1a2-Cre＋ and ATF3TGfl/flCol1a2-Cre-ischemic hearts revealed a distinct transcriptional profile in ATF3-overexpressing CFs,displaying pro-proliferation properties.BrdU-positive cells significantly increased in ATF3-overexpressing CFs than control CFs under angiotensin Ⅱ stimuli （11.5% vs.6.8%,t =31.599,P =0.001） or serum stimuli （31.6% vs.20.1%,t =31.599,P =0.001）.The 5（6）-carboxyfluorescein N-hydroxysuccinimidyl ester assay showed that the cell numbers of the P2 and P3 generations were higher in the ATF3-overexpressing CFs at 24 h （P2：91.6% vs.71.8%,t =8.465,P=0.015） and 48 h （P3：81.6% vs.51.1%,t =9.029,P =0.012） after semm stimulation.Notably,ATF3 overexpression-induced CF proliferation was clearly increased in the heart after MI injury.Conclusions：We identify that CF-specific ATF3 might contribute to be MI repair through upregulating the expression of cell cycle/proliferation-related genes and enhancing cell proliferation.

Transplantation of 5-azacytidine treated cardiac fibroblasts improves cardiac function of infarct hearts in rats

Background Cellular cardiomyoplasty by transplantation of various cell types has been investigated as potential treatments for the improvement of cardiac function after myocardial injury. A major barrier for the clinical application of cell transplantation is obtaining sufficiently large quantities of suitable cells. AIIogeneic cellular cardiomyoplasty may provide an alternative source of abundant, transplantable, myogenic cells by in vitro manipulation of cardiac fibroblasts using chemicals including 5-azacytidine. This study evaluated cardiomyogenic differentiation of cardiac fibroblasts, their survival in myocardial scar tissue, and the effect of the implanted cells on heart function. Methods Primary cardiac fibroblasts from neonatal rats were treated with 5-azacytidine （10 pmol/L） or control. Treatment of 5-azacytidine caused myogenic differentiation of cultured cardiac fibroblasts, as defined by elongation and fusion into multinucleated myotubes with sarcomeric structures as identified by electron microscopy, and positive immunostaining for cardiac specific proteins, troponin I and 13-myosin heavy chain （13-MHC） and the gap junction protein connexin 43. The myogenic cells （1.0x106） were transplanted into the infarcted myocardium 2 weeks after coronary artery occlusion. Results By 1 month after transplantation, the converted fibroblasts gave rise to a cluster of cardiac-like muscle cells that in the hearts occupied a large part of the scar with positive immunostaining for the myogenic proteins troponin I and 13-MHC. Engrafted cells also expressed the gap junction protein connexin 43 in a disorganized manner. There was no positive staining in the control hearts treated with injections of culture medium. Heart function was evaluated at 6 weeks after myocardial injury with echocardiographic and hemodynamic measurements. Improvement in cardiac function was seen in the hearts transplanted with the 5-azacytidine-treated cardiac fibroblasts which was absent in the hearts treated with control. Conclusion The 5-azacytidine has a unique capacity to induce myogenesis in cardiac fibroblasts in vitro and transplantation of cardiac-like muscle cells into ventricular scar tissue improves myocardial function.

Macrophage migration inhibitory factor suppresses angiotensinⅡ-induced expression of fibrosis-associated genes by inactivating Smad3 and activating Nrf2 in cardiac fibroblasts

Background Macrophage migration inhibitory factor （MIF） is a key pro-inflammatory cytokine, exhibiting antioxidant properties. However, the role of MIF in cardiac fibrosis is not well known. In the present study, the effects of MIF on Smad3 and Nrf2 signalings in cardiac fibroblasts were investigated. Methods Cardiac fibroblasts were isolated from 1-3 days old C57BL/6 mice, and the cardiac fibroblasts from passage 2 to 4 were used in this study. Expression of fibrosis-associated Collal, Col3al and oL-SMA in mouse cardiac fibroblasts was de- tected by immunofluorescence staining and Western-blot assay, respectively. Intracellular oxidants in mouse car- diac fibroblasts were measured by using the probe dichlorofluoroscindiacetate （DCFH-DA） under confocal mi- croscopy. Western-blot assay was also used to detect Smad3 and Nrf2, antioxidant proteins, MLL and HCF-1 in mouse cardiac fibroblasts. Results Immunofluorescence staining and Western- blot assay showed that MIF could markedly inhibit fibrosis-associated Collal, Col3al and oL-SMA expression in cardiac fibroblasts. DCFH- DA staining revealed that MIF can efficiently decrease reactive oxygen species （ROS） level in Ang-II-induced cardiac fibroblasts. Additionally, Smad3 activation was inhibited, but transcription factor Nrf2 and the downstream antioxidant genes, including HO-1, SOD-l, SOD2, Trx-2 and e-NOS, were increased in MIF-treated cardiac fibroblasts. MLL and HCF-lwere up-regulated by MIF, and either MLL knockdown or HCF-1 knock- down could consistently suppress Nrf2 expression in cardiac fibroblasts. Conclusions MIF possesses anti-fibro- sis effect by inactivating Smad3 and activating Nrf2 in cardiac fibroblasts.

Effects of Tetramethylpyrazine and Radix Salviae Miltiorrhizae on Collagen Synthesis and Proliferation of Cardiac Fibroblasts

Objective: To explore the effects of Tetramethylpyrazine (TMP) and Radix Salviae Miltiorrhizae (RSM) on collagen synthesis and proliferation of cardiac fibroblasts. Methods: Using collagenase and pancreatin digested rat cardiac tissue assay to isolate cardiac fibroblasts (FB). Different dosage of TMP, RSM and norepinephrine were used to study their effects on the collagen synthesis and proliferation of cultured cardiac FB. Results: Compared with the control group, moderate or high dosage TMP and RSM could significantly inhibit the collagen synthesis and the proliferation of cultured cardiac FB. Moreover, low-dose TMP (50 mg/L) and low-dose RSM (3 g/L) could antagonize the collagen synthesis and the proliferation of cultured cardiac FB stimulated by NE (500μg/L). Conclusion: Both TMP and RSM can inhibit the collagen synthesis and proliferation of cultured cardiac FB processes.The mechanisms of these effects might be correlated to their Ca++ antagonistic action. Original article on CJIM(Chin) 1998; 18(7): 423

Long non-coding RNAs in cardiac fibrosis:Regulation of cardiac fibroblasts

Background Cardiac fibrosis,characterized by excessive extracellular matrix(ECM)deposition and increased cardiac fibroblasts(CFs)activity,is a common pathology of various cardiovascular diseases.Cardiac fibrosis decreases ventricular compliance,increases diastolic filling pressure,decreases cardiac oxygen supply,and ultimately impairs the cardiac output.CFs are the main effecter cell type in regulating ECM and predominantly drive the fibrosis process.Despite the critical importance of CFs,our limited understanding of CFs impedes the development of potential therapies that effectively target this cell type and its pathological contribution to disease progression.Recently,long non-coding RNAs(lncRNAs)are emerging as important pathological and physiological regulators of cardiac fibrosis,shedding light on novel molecular mechanisms and potential therapeutic targets.This review discussed the current knowledge regarding the lnc RNAs involved in cardiac fibrosis and summarized their possible molecular mechanisms with special focus on the regulation of CFs.

Emodin alleviates cardiac fibrosis by suppressing activation of cardiac fibroblasts via upregulating metastasis associated protein 3

Excess activation of cardiac fibroblasts inevitably induces cardiac fibrosis. Emodin has been used as a natural medicine against several chronic diseases. The objective of this study is to determine the effects of emodin on cardiac fibrosis and the underlying molecular mechanisms. Intragastric administration of emodin markedly decreased left ventricular wall thickness in a mouse model of pathological cardiac hypertrophy with excess fibrosis induced by transaortic constriction(TAC) and suppressed activation of cardiac fibroblasts induced by angiotensin II(AngII). Emodin upregulated expression of metastasis associated protein 3(MTA3) and restored the MTA3 expression in the setting of cardiac fibrosis. Moreover, overexpression of MTA3 promoted cardiac fibrosis;in contrast, silence of MTA3 abrogated the inhibitory effect of emodin on fibroblast activation. Our findings unraveled the potential of emodin to alleviate cardiac fibrosis via upregulating MTA3 and highlight the regulatory role of MTA3 in the development of cardiac fibrosis.

Osthole decreases collagen Ⅰ/III contents and their ratio in TGF-β1-overexpressed mouse cardiac fibroblasts through regulating the TGF-β/Smad signaling pathway

The present study was designed to elucidate whether the mechanism by which osthole decreases collagenⅠ/III contents and their ratio is regulating the TGF-β/Smad signaling pathway in TGF-β1-overexpressed mouse cardiac fibroblasts(CFs). These CFs were cultured and treated with different concentrations of osthole. Our results showed that the TGF-β1 expression in the CFs transfected with that the recombinant expression plasmids pc DNA3.1(+)-TGF-β1 was significantly enhanced. After the CFs were treated with 1.25-5 μg·m L^(-1) of osthole for 24 h, the m RNA and protein expression levels of collagensⅠand III were reduced. The collagen Ⅰ/III ratio was also reduced. The m RNA and protein expression levels of TGF-β1, TβRⅠ, Smad2/3, P-Smad2/3, Smad4, and α-SMA were decreased, whereas the expression level of Smad7 was increased. These effects suggested that osthole could inhibit collagen Ⅰ and III expression and reduce their ratio via the TGF-β/Smad signaling pathway in TGF-β1 overexpressed CFs. These effects of osthole may play beneficial roles in the prevention and treatment of myocardial fibrosis.

Tenascin C upregulates interleukin-6 expression in human cardiac myofibroblasts via toll-like receptor 4

AIM:To investigate the effect of Tenascin C(TNC)on the expression of pro-inflammatory cytokines and matrixmetalloproteinases in human cardiac myofibroblasts(CMF).METHODS:CMF were isolated and cultured from patients undergoing coronary artery bypass grafting.Cultured cells were treated with either TNC(0.1μmol/L,24 h)or a recombinant protein corresponding to different domains of the TNC protein;fibrinogen-like globe(FBG)and fibronectin typeⅢ-like repeats(TNⅢ5-7)(both 1μmol/L,24 h).The expression of the proinflammatory cytokines;interleukin(IL)-6,IL-1β,TNFαand the matrix metalloproteinases;MMPs(MMP1,2,3,9,10,MT1-MMP)was assessed using real time RT-PCR and western blot analysis.RESULTS:TNC increased both IL-6 and MMP3(P<0.01)mR NA levels in cultured human CMF but had no significant effect on the other markers studied.The increase in IL-6 mR NA expression was mirrored by an increase in protein secretion as assessed by enzymelinked immunosorbant assay(P<0.01).Treating CMF with the recombinant protein FBG increased IL-6mR NA and protein(P<0.01)whereas the recombinant protein TNⅢ5-7 had no effect.Neither FBG nor TNⅢ5-7 had any significant effect on MMP3 expression.The expression of toll-like receptor 4(TLR4)in human CMF was confirmed by real time RT-PCR,western blot and immunohistochemistry.Pre-incubation of cells with TLR4neutralising antisera attenuated the effect of both TNC and FBG on IL-6 mR NA and protein expression.CONCLUSION:TNC up-regulates IL-6 expression in human CMF,an effect mediated through the FBG domain of TNC and via the TLR4 receptor.

红景天苷对血管紧张素Ⅱ诱导心肌成纤维细胞纤维化的保护作用

背景:目前已有研究表明红景天苷对多器官纤维化具有改善作用,但红景天苷对血管紧张素Ⅱ引起心肌成纤维细胞纤维化的保护作用尚不明确。目的:探究红景天苷对血管紧张素Ⅱ诱导的SD大鼠心肌成纤维细胞氧化应激及细胞外基质沉积的保护作用及其作用机制。方法:血管紧张素Ⅱ诱导心肌成纤维细胞纤维化,实验分为5组:正常对照组;模型组(培养基血管紧张素Ⅱ终浓度为1μmol/L);红景天苷低剂量和高剂量组(加入红景天苷50,100μmol/L处理2 h,再加入血管紧张素Ⅱ共同孵育48 h);SIRT1抑制剂组(加入SIRT1抑制剂EX52710μmol/L处理2 h,再加高剂量红景天苷处理2 h,再加血管紧张素Ⅱ共同孵育48 h)。使用CCK8法检测各组细胞活力,Transwell检测细胞迁移率,DCFH-DA荧光探针检测细胞内活性氧水平,试剂盒检测细胞内丙二醛含量、超氧化物歧化酶和过氧化氢酶活性;采用Western blot和qRT-PCR法检测心肌成纤维细胞纤维化相关mRNA和蛋白的表达水平。结果与结论:①经Vimentin荧光鉴定实验细胞为心肌成纤维细胞;②与正常对照组相比,模型组细胞活力、细胞迁移率、活性氧水平、丙二醛含量显著增加,超氧化物歧化酶和过氧化氢酶活性明显降低,LOXL2、α-SMA、胶原蛋白Ⅰ、胶原蛋白ⅢmRNA和蛋白表达显著升高,SIRT1蛋白表达水平明显降低(均P<0.01);与模型组相比,红景天苷低、高剂量组上述指标呈现相反的变化(均P<0.05),且红景天苷呈剂量依赖性调控;与红景天苷组相比,SIRT1抑制剂组细胞迁移率、α-SMA蛋白表达水平显著增加(均P<0.001);③结果表明,红景天苷对血管紧张素Ⅱ诱导的心肌成纤维细胞具有保护作用,能够剂量依赖性地抑制氧化应激和细胞外基质沉积。

心肌梗死后心肌纤维化小鼠心肌线粒体功能和能量代谢重塑相关性的转录组学分析

目的探究心肌梗死小鼠心肌纤维化过程中线粒体呼吸功能的变化,阐述其与糖酵解通量增加的相关性。方法选取40只C57BL/6N小鼠,随机分为实验组(心肌梗死组)和对照组(假手术组),20只/组。实验组采用结扎冠状动脉左前降支的方法构建小鼠心肌梗死模型,对照组除不对左前降支进行结扎外,其他操作均与实验组相同。选取心肌梗死后28d和假手术组小鼠各5只进行安乐死取材,取左心室组织样本进行转录组学测序,采用FPKM法计算基因表达量,寻找差异表达基因。并通过GO和KEGG数据库对差异基因进行富集分析,寻找影响疾病进程的相关通路。通过绘制热图,展示富集分析中显示的通路和相关基因的表达差异,并对体外培养的小鼠原代CFs通过促纤维化激动剂TGF-β1或溶剂对照干预,通过Seahorse实验检测其线粒体呼吸和糖酵解水平。结果通过心脏大体图和心脏超声验证心梗模型构建成功,心肌梗死组舒张期左心室内径增加(P<0.05),收缩期左心室内径增加更为显著(P<0.001),左心室射血分数明显下降,差异有统计学意义(P<0.0001)。与假手术组相比,心肌梗死组上调基因124个,下调基因106个。GO和KEGG富集分析显示差异表达基因显著富集在脂肪酸代谢、细胞器等代谢通路和线粒体中。基因表达热图显示脂肪酸β氧化和线粒体功能障碍,相反糖酵解水平增加。Seahorse实验中,与溶剂对照组(Vehicle组)相比,TGF-β1干预组心肌成纤维细胞基础和最大呼吸水平明显降低,基础和最大糖酵解水平升高,差异均有统计学意义(P<0.0001)。结论在心肌纤维化过程中,心肌成纤维细胞能量代谢重塑,线粒体功能下降,相反更倾向于通过糖酵解产生能量。

CircSLC8A1_005通过编码蛋白抑制心肌成纤维细胞纤维化表型的作用

【目的】探究环形RNA circSLC8A1_005调控心肌成纤维细胞纤维化表型的作用及可能机制。【方法】利用腺病毒介导在小鼠心肌成纤维细胞(mCFs)中过表达circSLC8A1_005,并检测mCFs中纤维化相关因I型胶原α1链(Col1a1)、Ⅲ型胶原α1链(Col3a1)和平滑肌肌动蛋白α2(Acta2)基因表达,通过EdU和划痕实验检测不同干预对mCFs的增殖和迁移能力的影响。双萤光素酶报告基因实验检测circSLC8A1_005包含的潜在核糖体进入序列(IRES)的活性。通过Western blot实验检测circSLC8A1_005翻译蛋白SLC8A1-605aa及其在细胞内分布情况。双萤光素酶报告基因实验检测SLC8A1-605aa对超氧化物歧化酶2(Sod2)的转录激活作用。通过RNA结合蛋白免疫沉淀(RIP)实验检测SLC8A1-605aa与Sod2 mRNA的结合作用。放线菌素D实验检测SLC8A1-605aa对Sod2 mRNA稳定性的影响。【结果】利用腺病毒可在mCFs中有效介导过表达circSLC8A1_005,过表达circSLC8A1_005可显著抑制mCFs中纤维化相关基因表达,抑制mCFs的增殖和迁移能力。双萤光素酶报告基因实验结果提示circ⁃SLC8A1_005包含的2个IRES具有活性。Western blot检测结果显示circSLC8A1_005可翻译预期大小为70 ku的SLC8A1-605aa蛋白,并主要分布于细胞核内。过表达SLC8A1-605aa和circSLC8A1_005可一致地抑制mCFs的纤维化表型。SLC8A1-605aa可特异上调超氧化物歧化酶2(Sod2)表达,但并不能转录激活Sod2表达;RIP实验结果显示SLC8A1-605aa与Sod2 mRNA有特异结合作用,而放线菌素D实验结果显示SLC8A1-605aa能够增强Sod2 mRNA的稳定性。【结论】CircSLC8A1_005通过翻译蛋白SLC8A1-605aa发挥抑制心肌成纤维细胞纤维化表型的作用,SLC8A1-605aa可能是潜在的用于心肌纤维化治疗的靶点。

CD73对体外心成纤维细胞和心肌细胞增殖与衰老的影响

目的:探讨CD73对心成纤维细胞(CFs)和心肌细胞(CMs)增殖和衰老的影响。方法:体外培养大鼠CFs和CMs,构建慢病毒CD73过表达载体,转染CFs和CMs。实验分为CD73过表达组(OE组)和对照组(NC组)。RT-PCR法检测转染病毒后各组细胞CD73基因表达水平;衰老相关β-半乳糖苷酶染色检测细胞衰老;MTT法检测细胞增殖;非损伤细胞功能分析仪检测细胞生长曲线和倍增时间;流式细胞术检测细胞周期;RT-PCR法检测增殖相关信号分子mRNA表达水平。结果:慢病毒转染CFs和CMs 72 h后,OE组CD73 mRNA水平明显高于NC组;NC组CFs和CMs衰老细胞数量多于OE组;OE组CMs转染后3~4 d的增殖能力大于NC组;CFs转染后3~4 d的增殖能力为2组无差异;转染第3天CFs细胞周期变化为2组G1期和S期所占细胞比例无差别,G2期所占比例OE组稍高于NC组;OE组CFs和CMs细胞生长曲线均显示生长指数高于NC组,CMs倍增时间2组差别不显著;CMs转染第3天PI3K和Akt mRNA的表达增高,血管内皮生长因子(VEGF)mRNA的表达变化不明显。结论:CD73对CFs增殖无明显影响,但抑制其衰老;CD73促进CMs的增殖且抑制其衰老;CD73可促进CMs高表达PI3K和Akt,但对VEGF表达无明显影响。