Effect of Efonidipine on TGF-β1–Induced Cardiac Fibrosis Through Smad2-Dependent Pathway in Rat Cardiac Fibroblasts

Ca2+ Signaling in Cardiovascular Fibroblasts

Fibrogenesis is a physiological process required for wound healing and tissue repair. It is induced by activation of quiescent fibroblasts, which first proliferate and then change their phenotype into migratory, contractile myofibroblasts. Myofibroblasts secrete extracellular matrix proteins, such as collagen, to form a scar. Once the healing process is terminated, most myofibroblasts undergo apoptosis. However, in some tissues, such as the heart, myofibroblasts remain active and sensitive to neurohumoral factors and inflammatory mediators, which lead eventually to excessive organ fibrosis. Many cellular processes involved in fibroblast activation, including cell proliferation, protein secretion and cell contraction, are highly regulated by intracellular Ca2+ signals. This review summarizes current research on Ca2+ signaling pathways underlying fibroblast activation. We present receptor- and ion channel-mediated Ca2+ signaling pathways, discuss how localized Ca2+ signals of the cell nucleus may be involved in fibroblast activation and present Ca2+-sensitive transcription pathways relevant for fibroblast biology. When investigated, we highlight how the function of Ca2+-handling proteins changes during cardiac and pulmonary fibrosis. Many aspects of Ca2+ signaling remain unexplored in different types of cardiovascular fibroblasts in relation to pathologies, and a better understanding of Ca2+ signaling in fibroblasts will help to design targeted therapies against fibrosis.

Hydrogen Sulfide and Irisin, Potential Allies in Ensuring Cardiovascular Health

Irisin is a myokine secreted under the influence of physical activity and exposure to low temperatures and through different exogenous stimuli by the cleavage of its precursor, fibronectin type III domain-containing protein 5 (FNDC5). It is mainly known for maintaining of metabolic homeostasis, promoting the browning of white adipose tissue, the thermogenesis process, and glucose homeostasis. Growing experimental evidence suggests the possible central role of irisin in the regulation of cardiometabolic pathophysiological processes. On the other side, hydrogen sulfide (H2S) is well recognized as a pleiotropic gasotransmitter that regulates several homeostatic balances and physiological functions and takes part in the pathogenesis of cardiometabolic diseases. Through the S-persulfidation of cysteine protein residues, H2S is capable of interacting with crucial signaling pathways, exerting beneficial effects in regulating glucose and lipid homeostasis as well. H2S and irisin seem to be intertwined; indeed, recently, H2S was found to regulate irisin secretion by activating the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)/FNDC5/irisin signaling pathway, and they share several mechanisms of action. Their involvement in metabolic diseases is confirmed by the detection of their lower circulating levels in obese and diabetic subjects. Along with the importance of metabolic disorders, these modulators exert favorable effects against cardiovascular diseases, preventing incidents of hypertension, atherosclerosis, heart failure, myocardial infarction, and ischemia-reperfusion injury. This review, for the first time, aims to explore the role of H2S and irisin and their possible crosstalk in cardiovascular diseases, pointing out the main effects exerted through the common molecular pathways involved.

Hydrogel-based cardiac repair and regeneration function in the treatment of myocardial infarction

A life-threatening illness that poses a serious threat to human health is myocardial infarction. It may result in a significant number of myocardial cells dying, dilated left ventricles, dysfunctional heart function, and ultimately cardiac failure. Based on the development of emerging biomaterials and the lack of clinical treatment methods and cardiac donors for myocardial infarction, hydrogels with good compatibility have been gradually applied to the treatment of myocardial infarction. Specifically, based on the three processes of pathophysiology of myocardial infarction, we summarized various types of hydrogels designed for myocardial tissue engineering in recent years, including natural hydrogels, intelligent hydrogels, growth factors, stem cells, and microRNA-loaded hydrogels. In addition, we also describe the heart patch and preparation techniques that promote the repair of MI heart function. Although most of these hydrogels are still in the preclinical research stage and lack of clinical trials, they have great potential for further application in the future. It is expected that this review will improve our knowledge of and offer fresh approaches to treating myocardial infarction.

Knockdown of HIPK2 attenuates angiotensin II-induced cardiac fibrosis in cardiac fibroblasts

ABSTRACT

Homeodomain-interacting protein kinase-2 (HIPK2), a member of an evolutionary conserved family of serine/threonine kinases, has been observed to be involved in the pathogenesis of fibrotic diseases. However, its role in cardiac fibrosis remains unclear. In the current study, we assessed the effect of HIPK2 on cardiac fibroblasts (CFs) in response to angiotensin II (Ang II) stimulation. The results indicated that HIPK2 expression was significantly increased in Ang II-induced CFs in a dose-dependent manner. Then, HIPK2 was knocked down in CFs to evaluate the roles of HIPK2. Knockdown of HIPK2 suppressed cell proliferation and migration in Ang II-induced CFs. The Ang II-caused increase in expression of α-SMA, a hallmark of myofibroblast differentiation, was decreased by knockdown of HIPK2. HIPK2 knockdown also reduced ECM production including type I collagen (Col I) and connective tissue growth factor (CTGF). Furthermore, knockdown of HIPK2 blocked the activation of TGF-β1/Smad pathway in Ang II-induced CFs. These data suggested that HIPK2 knockdown prevented the Ang II-induced activation of CFs via inhibiting TGF-β1/Smad pathway, indicating HIPK2 might be an anti-fibrosis target for the treatment of cardiac fibrosis.

Inhibition of SGLT1 Alleviates the Glycemic Variability-Induced Cardiac Fibrosis via Inhibition of Activation of Macrophage and Cardiac Fibroblasts

Glycemic variability has been considered one of the predictors of diabetes complications in patients with diabetes mellitus (DM). In this work, we evaluated whether glycemic variability induces cardiac fibrosis through regulating cardiac fibroblast activation and macrophage polarization. Moreover, we determined whether glucose transporter sodium-glucose cotransporter 1 (SGLT1) plays an important role in this process. Glycemic variability-induced mice were established using DM mice (GVDM mice), and intermittent high-glucose (IHG) treatment was used to simulate glycemic variability in RAW264.7 macrophages and cardiac fibroblasts. The short hairpin RNA for SGLT1 was used to knock down SGLT1. The results showed that glycemic variability aggravated the cardiac fibrosis in GVDM mice. Additionally, glycemic variability promoted the expression of fibrogenic cytokine and the extracellular matrix proteins in left ventricular tissues and cardiac fibroblasts. GVDM mice showed a higher incidence of macrophage infiltration and M1 polarization in left ventricular tissues. Moreover, IHG-promoted RAW264.7 macrophages tended to differentiate to M1 phenotype. SGLT1 knockdown alleviated cardiac fibrosis in GVDM mice and inhibited activations of cardiac fibroblast and macrophage M1 polarization. Our results indicated that glycemic variability aggravates cardiac fibrosis through activating cardiac fibroblast and macrophage M1 polarization, which could be partially inhibited by SGLT1 knockdown.

Cellular and Molecular Mechanism of Traditional Chinese Medicine on Ventricular Remodeling

Ventricular remodeling is related to the renin-angiotensin-aldosterone system, immune system, and various cytokines involved in inflammation, apoptosis, and cell signal regulation. Accumulated studies have shown that traditional Chinese medicine can significantly inhibit the process of ventricular remodeling, which may be related to the mechanism mentioned above. Here, we conducted a system overview to critically review the cellular and molecular mechanism of traditional Chinese medicine on ventricular remodeling. We mainly searched PubMed for basic research about the anti-ventricular remodeling of traditional Chinese medicine in 5 recent years, and then objectively summarized these researches. We included more than 25 kinds of Chinese herbal medicines including Qi-Li-Qian-Xin, Qi-Shen-Yi-Qi Pill, Xin-Ji-Er-Kang Formula, and Yi-Qi-Wen-Yang Decoction, and found that they can inhibit ventricular remodeling effectively through multi-components and multi-action targets, which are promoting the clinical application of traditional Chinese medicine.

Methyl Ferulic Acid Attenuates Human Cardiac Fibroblasts Differentiation and Myocardial Fibrosis by Suppressing pRB-E2F1/CCNE2 and RhoA/ROCK2 Pathway

Background: Myocardial fibrosis is a key pathological process after myocardial infarction, which leads to poor outcomes in patients at the end stage. Effective treatments for improving prognosis of myocardial fibrosis are needed to be further developed. Methyl ferulic acid (MFA), a biologically active monomer extracted and purified from the Chinese herbal medicine, is reported as an attenuator in many diseases. In this study, we aim to reveal the role it plays in myocardial fibrosis after myocardial infarction and its possible mechanism. Results: Firstly, we found that MFA attenuated the expression of fibrosis-related proteins and the ability of migration and proliferation in TGF-β1-induced human cardiac fibroblasts (HCFs). Then, myocardial fibrosis after myocardial infarction models on mouse was built to reveal the in vivo affection of MFA. After 28 days of treatments, fibrosis areas, cardiac function, and expression of fibrosis-related proteins were all improved in the MFA-treated group than the myocardial infarction group. Finally, to elucidate the mechanism of phenomenon we observed, we found that MFA attenuated HCF differentiation after myocardial infarction by suppressing the migration and proliferation in HCFs, which was by suppressing the pRB-E2F1/CCNE2 and the RhoA/ROCK2 pathway. Conclusion: Our findings showed that MFA attenuated the expression of fibrosis-related proteins, and the ability of migration and proliferation in HCFs improved the cardiac function of myocardial infarction mice; meanwhile, the mechanism of that was by suppressing the pRB-E2F1/CCNE2 and the RhoA/ROCK2 pathway.

Efonidipine Exerts Cerebroprotective Effect by Down-regulation of TGF-β/SMAD-2-Dependent Signaling Pathway in Diabetic Rats

Calcium overload and hyperglycemia are risks of stroke onset in diabetics. Our study was designed to elucidate the beneficial role of calcium channel blockers by targeting voltage-gated calcium channels in diabetes-associated cerebrovascular complications. Diabetes was induced using the neonatal streptozotocin rat model. After confirmation of diabetes, middle cerebral artery occlusion (MCAO) was carried out. The pre-treatment with 1 mg/kg/day efonidipine was administered for the period of 4 weeks. After 24 h of ischemic induction surgery, the neurological score was determined, and blood was collected for determination of biochemical parameters. Treatment with efonidipine showed a significant reduction in post-ischemic brain infract volume, brain hemisphere weight difference, neurological score, Na⁺-K⁺ ATPase activity, serum CK-MB, and LDH levels in normoglycemic and hyperglycemic MCAO-induced animals. While no significant changes in glucose and lipid levels were observed by treatment, efonidipine significantly decreased the levels of malondialdehyde, acetylcholine esterase, and nitrite levels and increased the levels of antioxidant markers in both normoglycemic and hyperglycemic MCAO animals. TGF-β and VEGF were found to be down-regulated after treatment with efonidipine in gene expression study. In conclusion, the study data supports the cerebroprotective role of efonidipine in diabetic animals possibly through TGF-β/SMAD-2 signaling pathway.

Protective effect of inhibiting TRPM7 expression on hypoxia post-treatment H9C2 cardiomyocytes

BACKGROUND

Transient receptor potential channel 7 (TRPM7) plays an important role in maintaining intracellular ion concentration and osmotic pressure.

OBJECTIVE

The purpose of this study was to investigate the role and mechanism of inhibiting the expression of TRPM7 in the treatment of distal myocardial ischemia.

METHODS

H9C2 cells were treated with hypoxia post-treatment and reperfusion, respectively, detect the expression of HIF-1α and TRPM7, the concentration of Ca2+ and the degree of apoptosis in the H9C2 cells. The relevant miRNAs targeting TRPM7 were searched, the TRPM7 interference vectors were constructed, and the interference of different interference vectors on TRPM7 in H9C2 cells was detected.

RESULTS

The results showed that hypoxia post-treatment treatment would lead to increased expression of miR-22-3p which directly targeting TRPM7, decreased expression of TRPM7, increased expression of HIF-α and increased intracellular Ca2+ concentration. While reperfusion can increase the expression of HIF-1α and TRPM7 in H9C2 cells and increase the degree of apoptosis.

CONCLUSION

Knockdown of TRPM7 can significantly reduce reperfusion injury in H9C2 cells, reduce the degree of apoptosis, and the TRPM7 interference vector can inhibit the expression of TRPM7 and have a certain protective effect on the reperfusion injury of H9C2 cells.

Chemical characterization and effects of volatile oil of Alpinia zerumbet on the quality of collagen deposition and caveolin-1 expression in a muscular fibrosis murine model

Abstract This study evaluated the effect of the volatile oil of Alpinia zerumbet (VOAz) on caveolin-1 gene expression and muscular fibrosis. The rats were immobilized to induce fibrosis of the gastrocnemius muscle, and they were treated with VOAz. Collagen quality was assessed by histology and the expression of the caveolin-1 (CAV-1) gene was evaluated using qPCR. Histomorphological analysis indicated a significant reduction in the perimeter, width, and intensity of collagen in the treated groups, thus showing that the oil was effective in regulating the quality of collagen at the three concentrations. The results of expression levels suggested a decrease in the lesioned group and in two treatment groups (0.0115 µg/g and 0.009 µg/g). However, with the lowest concentration (0.0065 µg/g), no significant difference was observed, with levels similar to those found in healthy tissue. Therefore, the results showed that VOAz has the potential to be a non-invasive and low-cost alternative to aid in the treatment of muscular fibrosis.

miR-29b-3p inhibits post-infarct cardiac fibrosis by targeting FOS

Background: Cardiac fibrosis after myocardial infarction (MI) is a major cause of heart deterioration. Recently, the roles of microRNAs (miRNAs) in various cardiovascular diseases associated with cardiac fibrosis have been extensively investigated. The present study aimed to investigate the role and mechanism of miR-29b-3p in cardiac fibrosis after MI.

Methods: miR-29b-3p expression in TGF-β1-activated cardiac fibroblasts (CFs) was detected by qRT-PCR. Cell Counting Kit-8 (CCK-8) and Trans-well assays were performed to evaluate CFs proliferation and migration ability, respectively. Protein expressions of α-SMA, collagen I, collagen III, MMP2, and MMP9 were examined by Western blot assay. Bioinformatics, luciferase, and RNA immunoprecipitation (RIP) assays were carried out to determine whether FOS was targeted by miR-29b-3p.

Results: TGF-β1 treatment dose-dependently curbed miR-29b-3p expression in CFs. miR-29b-3p restrained the promotive impacts of TGF-β1 on CFs proliferation, migration, and differentiation. FOS was affirmed to be a target of miR-29b-3p, elevated expression of FOS reversed the inhibitory effects of miR-29b-3p on cell proliferation, migration, and differentiation in TGF-β1-activated CFs.

Conclusion: miR-29b-3p degraded the pro-fibrosis effect induced by TGF-β1 via targeting FOS, providing a prospective therapeutic avenue for cardiac fibrosis after MI.

MiR-324-3p Regulates Fibroblast Proliferation via Targeting TGF-β1 in Atrial Fibrillation

Atrial fibrillation (AF), one of the common clinical arrhythmias, lacks effective treatment manners. Cardiac fibroblasts play an essential role in myocardial fibrosis and cardiac remodeling, which are involved in AF progression. Reportedly, MicroRNAs (miRNAs) regulate the myocardial fibrosis in AF. However, whether miR-324-3p involves myocardial fibrosis in AF and the tentative molecular mechanisms of miR-324-3p regulating cardiac fibroblasts during AF remains unknown. In the present study, miR-324-3p was found to be decreased in patients with AF and AF rat model. Next, we investigated the effect of miR-324-3p on myocardial fibroblast proliferation through miR-324-3p overexpression and found that miR-324-3p inhibited fibroblast proliferation in vitro. Furthermore, we found that miR-324-3p directly targeted transforming growth factor β1 in fibroblast, which may be involved in the development of myocardial fibrosis during AF. Meanwhile, miR-324-3p mimics treatment suppressed the PI3K/AKT signaling pathway in fibroblast. These results demonstrated a molecular mechanism of miR-324-3p regulating fibroblast proliferation in vitro, which might provide a novel potential treatment manner in AF in clinic.

Doxycycline Improves Fibrosis-Induced Abnormalities in Atrial Conduction and Vulnerability to Atrial Fibrillation in Chronic Intermittent Hypoxia Rats

Background

The structural remodeling of atrial architecture, especially increased amounts of fibrosis, is a critical substrate to atrial fibrillation (AF). Doxycycline (Doxy) has recently been shown to exert protective effects against fibrogenic response. This study investigated whether doxycycline (Doxy) can sufficiently ameliorate the fibrosis-induced changes of atrial conduction and AF vulnerability in a chronic intermittent hypoxia (CIH) rat model.

Material/Methods

Sixty rats were randomized into 3 groups: Control, CIH, and CIH with Doxy treatment (DOXY) group. CIH rats were exposed to CIH (6 h/d) and Doxy-treated rats were treated with Doxy during processing CIH. After 6 weeks, echocardiographic and hemodynamic parameters were measured. Isolated atrial epicardial activation mapping and heart electrophysiology were performed. The extent of atrial interstitial fibrosis were estimated by Masson’s trichrome staining. The expression levels of TGF-β1 and downstream factors were determined by real-Time PCR, immunohistochemistry, and Western blot analysis.

Results

Compared to Control rats, the CIH rats showed significant atrial interstitial fibrosis, longer inter-atrial conduction time, and elevated conduction inhomogeneity and AF inducibility, and the expression of TGF-β1, TGF-βRI, TGF-βRII, P-Smad2/3, α-SMA, CTGF, and Collagen I were significantly increased, whereas the velocity of atrial conduction and the expression of miR-30c were dramatically decreased. All of these changes were significantly improved by Doxy treatment.

Conclusions

The findings suggested that Doxy can profoundly mitigate atrial fibrosis, conduction inhomogeneity as well as high AF inducibility secondary to fibrosis in a CIH rat model through suppressing the TGF-β1 signaling pathway.

Spatiotemporal delivery of basic fibroblast growth factor to directly and simultaneously attenuate cardiac fibrosis and promote cardiac tissue vascularization following myocardial infarction

Following myocardial infarction (MI), the destruction of vasculature in the infarcted heart muscle and progression of cardiac fibrosis lead to cardiac function deterioration. Vascularization of the damaged tissue and prevention of cardiac fibrosis represent promising strategies to improve cardiac function. Herein we have developed a bFGF release system with suitable release kinetics to simultaneously achieve the two goals. The release system was based on an injectable, thermosensitive, and fast gelation hydrogel and bFGF. The hydrogel had gelation time <7 s. It can quickly solidify upon injection into tissue so as to increase drug retention in the tissue. Hydrogel complex modulus can be tuned by hydrogel solution concentration. The complex modulus of 176.6 Pa and lower allowed cardiac fibroblast to maintain its phenotype. Bioactive bFGF was able to gradually release from the hydrogel for 4 weeks. The released bFGF promoted cardiac fibroblast survival under ischemic conditions mimicking those of the infarcted hearts. It also attenuated cardiac fibroblasts from differentiating into myofibroblasts in the presence of TGFβ when tested in 3D collagen model mimicking the scenario when the bFGF release system was injected into hearts. Furthermore, the released bFGF stimulated human umbilical endothelial cells to form endothelial lumen. After 4 weeks of implantation into infarcted hearts, the bFGF release system significantly increased blood vessel density, decreased myofibroblast density and collagen content, augmented cardiac cell survival/proliferation, and reduced macrophage density. In addition, the bFGF release system significantly increased cardiac function. These results demonstrate that delivery of bFGF with appropriate release kinetics alone may represent an efficient approach to control cardiac remodeling after MI.

Acetazolamide attenuates cardiac fibrosis induced by aortic constriction through inhibiting transforming growth factor-β1/Smad2 signaling pathway in mice

The effect and mechanism of acetazolamide on cardiac fibrosis induced by transverse aortic constriction (TAC) were investigated. C57BL/6 mice were subjected to TAC or sham operation and then were orally gavaged with acetazolamide (20 mg/kg/day). After 4 weeks of operation, cardiac function was detected by echocardiography. Interstitial fibrosis was stained with Masson's trichrome. The expression of α-smooth muscle actin (α-SMA), collagen I, transforming growth factor-β1 (TGF-β1) and Smad2 were measured by western blotting. The TAC mice displayed significant cardiac dysfunction and fibrosis. The expression of α-SMA, collagen I, TGF-β1 and p-Smad2 in the TAC group was higher than those in the sham group. By contrast, acetazolamide administration inhibited interstitial fibrosis, as well as improved cardiac dysfunction induced by TAC. Acetazolamide also reduced the expression of α-SMA, collagen I, TGF-β1 and p-Smad2 in the TAC mice. Acetazolamide was able to attenuate cardiac fibrosis and improve cardiac dysfunction. The molecular mechanism involved in the anti-fibrotic effect of acetazolamide possibly was through inhibiting TGF-β1/Smad2 signaling pathway.

Modulation of miR-10a-mediated TGF-β1/Smads signaling affects atrial fibrillation-induced cardiac fibrosis and cardiac fibroblast proliferation

Atrial fibrillation (AF) rat models and rat cardiac fibroblasts (CFs) with overexpressed or inhibited miR-10a were used to investigate the possible role of miR-10a-mediated transforming growth factor-β (TGF-β1)/Smads signaling in cardiac fibrosis and fibroblast proliferation in rats with AF. Gene ontology and pathway enrichment analyses were used to identify the possible function of miR-10a in cardiac fibrosis. The results showed that overexpressed miR-10a significantly prolonged the duration of AF, further elevated the collagen volume fraction (CVF), and increased the viability of CFs in AF rats; these findings were in contrast with the findings for rats with inhibition of miR-10a (all P<0.05). Moreover, miR-10a overexpression could promote miR-10a, collagen-I, collagen III, α-SMA, and TGF-β1 protein expression and increase the levels of hydroxyproline but reduced Smad7 protein expression in atrial tissues and CFs in AF rats. Not surprisingly, inhibiting miR-10a led to completely contrasting results (all P<0.05). Moreover, TGF-β1 treatment could reverse the inhibitory effect of miR-10a down-regulation on cardiac fibrosis in CFs. Bioinformatics analysis and luciferase reporter assay results demonstrated that miR-10a bound directly to the 3′-UTR of BCL6, which is involved in cell growth and proliferation. Thus, our study indicate that down-regulation of miR-10a may inhibit collagen formation, reduce atrial structure remodeling, and decrease proliferation of CFs, eventually suppressing cardiac fibrosis in AF rats via inhibition of the TGF-β1/Smads signaling pathway.

Matrine suppresses cardiac fibrosis by inhibiting the TGF‑β/Smad pathway in experimental diabetic cardiomyopathy

Cardiac fibrosis is one of the pathological characteristics of diabetic cardiomyopathy (DbCM). Matrine treatment has proven to be effective in cases of organ fibrosis and cardiovascular diseases. In the present study, the anti-fibrosis-associated cardioprotective effects of matrine on DbCM were investigated. Rats with experimental DbCM were administered matrine orally. Cardiac functions were evaluated using invasive hemodynamic examinations. Cardiac compliance was assessed in isolated hearts. Using Sirius Red and fluorescence staining, the collagen in diabetic hearts was visualized. MTT assay was used to select non-cytotoxic concentrations of matrine, which were subsequently used to treat isolated cardiac fibroblasts incubated under various conditions. Western blotting was performed to assess activation of the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. Rats with DbCM exhibited impaired heart compliance and left ventricular (LV) functions. Excessive collagen deposition in cardiac tissue was also observed. Furthermore, TGF-β1/R-Smad (Smad2/3) signaling was revealed to be markedly activated; however, the expression of inhibitory Smad (I-Smad, also termed Smad7) was reduced in DbCM. Matrine administration led to a marked recovery in LV function and heart compliance by exerting inhibitory effects on TGF-β1/R-Smad signaling pathway-induced fibrosis without affecting I-Smad. Incubation with a high concentration of glucose triggered the TGF-β1/R-Smad (Smad2/3) signaling pathway and suppressed I-Smad signaling transduction in cultured cardiac fibroblasts, which led to an increase in the synthesis of collagen. After cardiac fibroblasts had been treated with matrine at non-cytotoxic concentrations without affecting I-Smad, matrine blocked TGF-β1/R-Smad signaling transduction to repress collagen production and deposition. In conclusion, the results of the present study demonstrated that TGF-β1/Smad signaling-associated cardiac fibrosis is involved in the impairment of heart compliance and LV dysfunction in DbCM. By exerting therapeutic effects against cardiac fibrosis via its influence on TGF-β1/Smad signaling, matrine exhibited cardioprotective effects in DbCM.

Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor

Angiotensin II (Ang II) is known to be involved in the progression of ventricular dysfunction and heart failure by eliciting cardiac fibrosis. The purpose of this study was to demonstrate whether treatment with an antioxidant compound, edaravone, reduces cardiac fibrosis and improves ventricular function by inhibiting Ang II AT1 receptor. The study was conducted in a rat model of transverse aortic constriction (TAC). In control, rats were subjected to 8 weeks of TAC. In treated rats, edaravone (10 mg/kg/day) or Ang II AT1 receptor blocker, telmisartan (10 mg/kg/day) was administered by intraperitoneal injection or gastric gavage, respectively, during TAC. Relative to the animals with TAC, edaravone reduced myocardial malonaldehyde level and increased superoxide dismutase activity. Protein level of the AT1 receptor was reduced and the AT2 receptor was upregulated, as evidenced by the reduced ratio of AT1 over AT2 receptor (0.57±0.2 vs 3.16±0.39, p<0.05) and less locally expressed AT1 receptor in the myocardium. Furthermore, the protein level of angiotensin converting enzyme 2 was upregulated. In coincidence with these changes, edaravone significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced levels of transforming growth factor beta 1 and Smad2/3. Collagen I synthesis was inhibited and collagen-rich fibrosis was attenuated. Relative to the TAC group, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (204±51 vs 110±19 mmHg, p<0.05) and ejection fraction (82%±3% vs 60%±5%, p<0.05). Treatment with telmisartan provided a comparable level of protection as compared with edaravone in all the parameters measured. Taken together, edaravone treatment ameliorates cardiac fibrosis and improves left ventricular function in the pressure overload rat model, potentially via suppressing the AT1 receptor-mediated signaling pathways. These data indicate that edaravone might be selected in combination with other existing drugs in preventing progression of cardiac dysfunction in heart failure.

Dust particles-induced intracellular Ca2+ signaling and reactive oxygen species in lung fibroblast cell line MRC5

Epidemiologic interest in particulate matter (PM) is growing particularly because of its impact of respiratory health. It has been elucidated that PM evoked inflammatory signal in pulmonary epithelia. However, it has not been established Ca²⁺ signaling mechanisms involved in acute PM-derived signaling in pulmonary fibroblasts. In the present study, we explored dust particles PM modulated intracellular Ca²⁺ signaling and sought to provide a therapeutic strategy by antagonizing PM-induced intracellular Ca²⁺ signaling in human lung fibroblasts MRC5 cells. We demonstrated that PM10, less than 10 µm, induced intracellular Ca²⁺ signaling, which was mediated by extracellular Ca²⁺. The PM10-mediated intracellular Ca²⁺ signaling was attenuated by antioxidants, phospholipase blockers, polyADPR polymerase 1 inhibitor, and transient receptor potential melastatin 2 (TRPM2) inhibitors. In addition, PM-mediated increases in reactive oxygen species were attenuated by TRPM2 blockers, clotrimazole (CLZ) and N-(p-amylcinnamoyl) anthranilic acid (ACA). Our results showed that PM10 enhanced reactive oxygen species signal by measuring DCF fluorescence and the DCF signal attenuated by both TRPM2 blockers CLZ and ACA. Here, we suggest functional inhibition of TRPM2 channels as a potential therapeutic strategy for modulation of dust particle-mediated signaling and oxidative stress accompanying lung diseases.

Induced Pluripotent Stem Cells Inhibit Bleomycin-Induced Pulmonary Fibrosis in Mice through Suppressing TGF-β1/Smad-Mediated Epithelial to Mesenchymal Transition

Pulmonary fibrosis is a progressive and irreversible fibrotic lung disorder with high mortality and few treatment options. Recently, induced pluripotent stem (iPS) cells have been considered as an ideal resource for stem cell-based therapy. Although, an earlier study demonstrated the therapeutic effect of iPS cells on pulmonary fibrosis, the exact mechanisms remain obscure. The present study investigated the effects of iPS cells on inflammatory responses, transforming growth factor (TGF)-β1 signaling pathway, and epithelial to mesenchymal transition (EMT) during bleomycin (BLM)-induced lung fibrosis. A single intratracheal instillation of BLM (5 mg/kg) was performed to induce pulmonary fibrosis in C57BL/6 mice. Then, iPS cells (c-Myc-free) were administrated intravenously at 24 h following BLM instillation. Three weeks after BLM administration, pulmonary fibrosis was evaluated. As expected, treatment with iPS cells significantly limited the pathological changes, edema, and collagen deposition in lung tissues of BLM-induced mice. Mechanically, treatment with iPS cells obviously repressed the expression ratios of matrix metalloproteinase-2 (MMP-2) to its tissue inhibitor -2 (TIMP-2) and MMP-9/TIMP-1 in BLM-induced pulmonary tissues. In addition, iPS cell administration remarkably suppressed BLM-induced up-regulation of pulmonary inflammatory mediators, including tumor necrosis factor-α, interleukin (IL)-1β, IL-6, inducible nitric oxide synthase, nitric oxide, cyclooxygenase-2 and prostaglandin E₂. We further demonstrated that transplantation of iPS cells markedly inhibited BLM-mediated activation of TGF-β1/Mothers against decapentaplegic homolog 2/3 (Smad2/3) and EMT in lung tissues through up-regulating epithelial marker E-cadherin and down-regulating mesenchymal markers including fibronectin, vimentin and α-smooth muscle actin. Moreover, in vitro, iPS cell-conditioned medium (iPSC-CM) profoundly inhibited TGF-β1-induced EMT signaling pathway in mouse alveolar epithelial type II cells (AECII). Collectively, our results suggest that transplantation of iPS cells could suppress inflammatory responses, TGF-β1/Smad2/3 pathway and EMT during the progression of BLM-induced pulmonary fibrosis, providing new useful clues regarding the mechanisms of iPS cells in the treatment for this disease.

Delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells

This study examined the effect of delphinidin on high glucose-induced cell proliferation and collagen synthesis in mesangial cells. Glucose dose-dependently (5.6-25 mM) increased cell proliferation and collagen I and IV mRNA levels, whereas pretreatment with delphinidin (50 μM) prevented cell proliferation and the increased collagen mRNA levels induced by high glucose (25 mM). High glucose increased reactive oxygen species (ROS) generation, and this was suppressed by pretreating delphinidin or the antioxidant N-acetyl cysteine. NADPH oxidase (NOX) 1 was upregulated by high glucose, but pretreatment with delphinidin abrogated this upregulation. Increased mitochondrial superoxide by 25 mM glucose was also suppressed by delphinidin. The NOX inhibitor apocynin and mitochondria-targeted antioxidant Mito TEMPO inhibited ROS generation and cell proliferation induced by high glucose. Phosphorylation of extracellular signal regulated kinase (ERK)1/2 was increased by high glucose, which was suppressed by delphinidin, apocynin or Mito TEMPO. Furthermore, PD98059 (an ERK1/2 inhibitor) prevented the high glucose-induced cell proliferation and increased collagen mRNA levels. Transforming growth factor (TGF)-β protein levels were elevated by high glucose, and pretreatment with delphinidin or PD98059 prevented this augmentation. These results suggest that delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells.

Effect and Mechanism of QiShenYiQi Pill on Experimental Autoimmune Myocarditis Rats

Background

To observe the effect of QiShenYiQi pill (QSYQ) on experimental autoimmune myocarditis rats, and to explore its mechanism of action.

Material/methods

Lewis rats underwent the injection of myocardial myosin mixed with Freund’s complete adjuvant were randomized into 3 groups: model, valsartan, and QSYQ groups. Rats injected with phosphate-buffered saline (PBS) mixed with Freund’s complete adjuvant were used as the control group. Rats were euthanized at 4 and 8 weeks, and we weighed rat body mass, heart mass, and left ventricular mass. Myocardium sections were stained with hematoxylin and eosin (H&E) and Masson trichrome. Myocardial TGF-β1 and CTGF protein expression was detected by immunohistochemistry, and myocardial TGF-β1 and CTGF mRNA expression was detected by real-time qPCR.

Results

QSYQ reduced HMI and LVMI, as well as the histological score of hearts and CVF, which further decreased over time, and its effect was significantly greater than that of valsartan at 4 and 8 weeks. After 4 weeks, QSYQ inhibited the protein and mRNA expression of TGF-β1 and CTGF, and its effect on lowering CTGF was significantly greater than that of valsartan. In addition, after 8 weeks, QSYQ also inhibited the protein and mRNA expression of CTGF, whereas there was no significant difference in the expression of myocardial TGF-β1.

Conclusions

This study provides evidence that QSYQ can improve cardiac remodeling of experimental autoimmune myocarditis rats. It also effectively improved the degree of myocardial fibrosis, which is related to the mechanism of regulation of TGF-β1 CTGF.

Calcium Homeostasis and Ionic Mechanisms in Pulmonary Fibroblasts

Fibroblasts are key cellular mediators of many chronic interstitial lung diseases, including idiopathic pulmonary fibrosis, scleroderma, sarcoidosis, drug-induced interstitial lung disease, and interstitial lung disease in connective tissue disease. A great deal of effort has been expended to understand the signaling mechanisms underlying the various cellular functions of fibroblasts. Recently, it has been shown that Ca(2+) oscillations play a central role in the regulation of gene expression in human pulmonary fibroblasts. However, the mechanisms whereby cytosolic [Ca(2+)] are regulated and [Ca(2+)] oscillations transduced are both poorly understood. In this review, we present the general concepts of [Ca(2+)] homeostasis, of ionic mechanisms responsible for various Ca(2+) fluxes, and of regulation of gene expression by [Ca(2+)]. In each case, we then also summarize the original findings that pertain specifically to pulmonary fibroblasts. From these data, we propose an overall signaling cascade by which excitation of the fibroblasts triggers pulsatile release of internally sequestered Ca(2+), which, in turn, activates membrane conductances, including voltage-dependent Ca(2+) influx pathways. Collectively, these events produce recurring Ca(2+) oscillations, the frequency of which is transduced by Ca(2+)-dependent transcription factors, which, in turn, orchestrate a variety of cellular events, including proliferation, synthesis/secretion of extracellular matrix proteins, autoactivation (production of transforming growth factor-β), and transformation into myofibroblasts. That unifying hypothesis, in turn, allows us to highlight several specific cellular targets and therapeutic intervention strategies aimed at controlling unwanted pulmonary fibrosis. The relationships between Ca(2+) signaling events and the unfolded protein response and apoptosis are also explored.

Fibrotic atrial cardiomyopathy, atrial fibrillation, and thromboembolism: mechanistic links and clinical inferences

The association of atrial fibrillation (AF) with ischemic stroke has long been recognized; yet, the pathogenic mechanisms underlying this relationship are incompletely understood. Clinical schemas, such as the CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, sex category) score, incompletely account for thromboembolic risk, and emerging evidence suggests that stroke can occur in patients with AF even after sinus rhythm is restored. Atrial fibrosis correlates with both the persistence and burden of AF, and gadolinium-enhanced magnetic resonance imaging is gaining utility for detection and quantification of the fibrotic substrate, but methodological challenges limit its use. Factors related to evolution of the thrombogenic fibrotic atrial cardiomyopathy support the view that AF is a marker of stroke risk regardless of whether or not the arrhythmia is sustained. Antithrombotic therapy should be guided by a comprehensive assessment of intrinsic risk rather than the presence or absence of AF at a given time.

Angiotensin-converting enzyme-2 overexpression improves atrial remodeling and function in a canine model of atrial fibrillation

BACKGROUND

Atrial fibrosis is an important factor in initiating and maintaining atrial fibrillation. The purpose of this study was to test the hypothesis that atrial angiotensin-converting enzyme-2 (ACE2) overexpression might inhibit atrial collagen accumulation and improve atrial remodeling in a canine atrial pacing model.

METHODS AND RESULTS

Thirty-two mongrel dogs of both genders were divided randomly into 4 groups: sham-operated, control, gene therapy with adenovirus-enhanced green fluorescent protein (Ad-EGFP), and gene therapy with Ad-ACE2. All of the dogs in the control, Ad-EGFP, and Ad-ACE2 groups were paced at 450 bpm for a period of 14 days. The dogs in the sham group were instrumented without pacing. After 2 weeks, all of the dogs underwent a thoracotomy operation and received epicardial gene painting. On post-gene transfer day 21, the animals underwent electrophysiology, histology, and molecular studies. The percentage of fibrosis in the Ad-ACE2 group was markedly lower than the percentage in the control and Ad-EGFP groups. Compared with the other groups, ACE2 expression was increased significantly in the Ad-ACE2 group. Compared with the sham and Ad-ACE2 groups, the expression levels of transforming growth factor-β1 and Smad3 were significantly higher in the Ad-EGFP and control groups; however, the expression levels of Smad7 were lower in the atrial tissue as detected by Western blot and reverse transcription polymerase chain reaction.

CONCLUSIONS

Our results demonstrate that the overexpression of ACE2 inhibits atrial collagen accumulation and improves left atrial remodeling and function in a canine model of atrial fibrillation. Thus, targeted gene ACE2 therapy provides a promising approach for the treatment of atrial fibrillation.

Hydrogen sulfide alleviates myocardial collagen remodeling in association with inhibition of TGF-β/Smad signaling pathway in spontaneously hypertensive rats

The study was designed to explore the role and possible mechanisms of hydrogen sulfide (H2S) in the regulation of myocardial collagen remodeling in spontaneously hypertensive rats (SHRs). We treated nine-week-old male SHRs and age- and sex-matched Wistar-Kyoto rats (WKYs) with NaHS (90 μmol/kg(-1)·day(-1)) for 9 wks. At 18 wks, plasma H2S, tail arterial pressure, morphology of the heart, myocardial ultrastructure and collagen volume fraction (CVF), myocardial expressions of collagen I and III protein and procollagen I and III mRNA, transforming growth factor-β1 (TGF-β1), TGF-β type I receptor (TβR-I), type II receptor (TβR-II), p-Smad2 and 3, matrix metalloproteinase (MMP)-13 and tissue inhibitors of MMP (TIMP)-1 proteins were determined. TGF-β1-stimulated cultured cardiac fibroblasts (CFs) were used to further study the mechanisms. The results showed that compared with WKYs, SHRs showed a reduced plasma H2S, elevated tail artery pressure and increased myocardial collagen, TGF-β1, TβR-II, p-Smad2 and p-Smad3 expressions. However, NaHS markedly decreased tail artery pressure and inhibited myocardial collagen, TGF-β1, TβR-II, p-Smad2 and p-Smad3 protein expressions, but H2S had no effect on the expressions of MMP-13 and TIMP-1. Hydralazine reduced blood pressure but had no effect on myocardial collagen, MMP-13 and TIMP-1 expressions and TGF-β1/Smad signaling pathway. H2S prevented activation of the TGF-β1/Smad signaling pathway and abnormal collagen synthesis in CFs. In conclusion, the results suggested that H2S could prevent myocardial collagen remodeling in SHR. The mechanism might be associated with inhibition of collagen synthesis via TGF-β1/Smad signaling pathway.

Engineering TGF-β superfamily ligands for clinical applications

TGF-β superfamily ligands govern normal tissue development and homeostasis, and their dysfunction is a hallmark of many diseases. These ligands are also well defined both structurally and functionally. This review focuses on TGF-β superfamily ligand engineering for therapeutic purposes, in particular for regenerative medicine and musculoskeletal disorders. We describe the key discovery that structure-guided mutation of receptor-binding epitopes, especially swapping of these epitopes between ligands, results in new ligands with unique functional properties that can be harnessed clinically. Given the promising results with prototypical engineered TGF-β superfamily ligands, and the vast number of such molecules that remain to be produced and tested, this strategy is likely to hold great promise for the development of new biologics.

SLC41A1 knockdown inhibits angiotensin II-induced cardiac fibrosis by preventing Mg(2+) efflux and Ca(2+) signaling in cardiac fibroblasts

Na(+)/Mg(2+) exchanger plays an important role in cardiovascular system, but the molecular mechanisms still largely remain unknown. The Solute Carrier family 41A1 (SLC41A1), a novel Mg(2+) transporter, recently was found to function as Na(+)/Mg(2+) exchanger, which mainly regulates the intracellular Mg(2+) ([Mg(2+)]i) homeostasis. Our present studies were designed to investigate whether SLC41A1 impacts on the fibrogenesis of cardiac fibroblasts under Ang II stimulation. Our results showed that quinidine, a prototypical inhibitor of Na(+)/Mg(2+) exchanger, inhibited Ang II-induced cardiac fibrosis via attenuating the overexpression of vital biomarkers of fibrosis, including connective tissue growth factor (CTGF), fibronectin (FN) and α-smooth muscle actin (α-SMA). In addition, quinidine also decreased the Ang II-mediated elevation of concentration of intracellular Ca(2+) ([Ca(2+)]i) and extrusion of intracellular Mg(2+). Meanwhile, silencing SLC41A1 by RNA interference also impaired the elevation of [Ca(2+)]i, [Mg(2+)]i efflux and the upregulation of CTGF, FN and α-SMA provoked by Ang II. Furthermore, we found that Ang II-mediated activation of NFATc4 translocation decreased in SLC41A1-siRNA cells. These results support the notion that rapid extrusion of intracellular Mg(2+) is mediated by SLC41A1 and provide the evidence that the intracellular free Ca(2+) concentration is influenced by extrusion of intracellular Mg(2+) which facilitates fibrosis reaction in cardiac fibroblasts.

Total polysaccharide of Yupingfeng protects against bleomycin-induced pulmonary fibrosis via inhibiting transforming growth factor-β1-mediated type I collagen abnormal deposition in rats

Objective

This study was to explore the antifibrotic effect and the possible mechanism of total polysaccharides of Yupingfeng (YPF-P) on bleomycin (BLM)-induced pulmonary fibrosis in rats.

Methods

Pulmonary fibrosis was induced in Sprague-Dawley rats by BLM (5 mg/kg), killed 14 and 28 days after BLM administration by abdominal aorta exsanguination and removed the lungs. Lung coefficient was counted at the same time. Besides, H&E and Masson's trichrome staining for histopathological changes of lung tissues were observed. Additionally, western blotting and immunohistochemical staining techniques were used to detect expression of transforming growth factor-β1 (TGF-β1), type I collagen (Col-I) and α-smooth muscle actin (α-SMA). Finally, the levels of Col-I and hydroxyproline (HYP) in lung tissues were also utilized.

Key findings

YPF-P alleviated the increase of lung coefficient induced by BLM instillation in pulmonary fibrosis rat, pathologic changes and collagen distribution were obviously ameliorated, while the increase of α-SMA-positive cells and TGF-β1 expression was prevented after YPF-P treatment. Moreover, the contents of HYP and Col-I were decreased in YPF-P group.

Conclusions

YPF-P had antifibrotic effect in experiment, which may reduce the synthesis and promote the deposition of Col-I via suppressing the increase of TGF-β1-mediated activation of myofibroblasts.

Inhibitory effect of ethyl acetate extract of Aristolochia yunnanensis on cardiac fibrosis through extracellular signal-regulated kinases 1/2 and transforming growth factor β/small mother against decapentaplegic signaling pathways

Aristolochia yunnanensis, known as Nan Mu Xiang in traditional Chinese medicine, has long been used to treat hypertension and chest pain. In this study, the effect of ethyl acetate extract of Nan Mu Xiang (NMX) on cardiac fibrosis was assessed in vitro by cultured adult rat cardiac fibroblasts with angiotensin II (AngII) stimulation, and in vivo by rats with abdominal aorta constriction (AAC). In cultured adult rat cardiac fibroblasts stimulated by AngII, NMX inhibited cardiac fibroblast proliferation, reduced the expression of fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor β (TGF-β) in a dose-dependent manner; and suppressed AngII-induced phosphorylation of extracellular signal-regulated kinase (ERK)1/2, C- rapidly accelerated fibrosarcoma (C-Raf), and small mother against decapentaplegic (Smad) 2. Similar results were also observed in AAC rats with intraperitoneal injection of NMX, which not only ameliorated myocardial fibrosis, but also improved cardiac function. The therapeutic effect of NMX on myocardial fibrosis is attributed mainly to the inhibition of ERK and the TGF-β/Smad signaling pathways. NMX may be a promising potential drug candidate for myocardial fibrosis.

Role of caveolin-1 in atrial fibrillation as an anti-fibrotic signaling molecule in human atrial fibroblasts

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population; yet, the precise mechanisms resulting in AF are not fully understood. Caveolin-1 (Cav-1), the principal structural component of caveolae organelles in cardiac fibroblasts, is involved in several cardiovascular conditions; however, the study on its function in atrium, in particular, in AF, is still lacking. This report examines the hypothesis that Cav-1 confers an anti-AF effect by mediating atrial structural remodeling through its anti-fibrotic action. We evaluated the expression of Cav-1, transforming growth factor-β1 (TGF-β1), and fibrosis in atrial specimens of 13 patients with AF and 10 subjects with sinus rhythm, and found that the expression of Cav-1 was significantly downregulated, whereas TGF-β1 level, collagens I/III contents and atrial fibrosis were markedly increased, in AF. Western blot analysis demonstrated that treatment of human atrial fibroblasts (HAFs) with TGF-β1 resulted in a concentration- and time-dependent repression of Cav-1. Downregulation of Cav-1 with siRNA increased the TGF-β1-induced activation of Smad signal pathway and collagens production in HAFs. Furthermore, incubation of HAFs with the peptides derived from Cav-1 to achieve Cav-1 gain-of-function abolished the TGF-β1-induced production of collagens I/III and decreases of MMP-2/-9 expression. Therefore it was concluded that Cav-1 is an important anti-AF signaling mediator by conferring its anti-fibrotic effects in atrium.

Regulation of fetal gene expression in heart failure

During the processes leading to adverse cardiac remodeling and heart failure, cardiomyocytes react to neurohumoral stimuli and biomechanical stress by activating pathways that induce pathological hypertrophy. The gene expression patterns and molecular changes observed during cardiac hypertrophic remodeling bare resemblance to those observed during fetal cardiac development. The re-activation of fetal genes in the adult failing heart is a complex biological process that involves transcriptional, posttranscriptional and epigenetic regulation of the cardiac genome. In this review, the mechanistic actions of transcription factors, microRNAs and chromatin remodeling processes in regulating fetal gene expression in heart failure are discussed.

Expression of HGF, MMP-9 and TGF-β1 in the CSF and cerebral tissue of adult rats with hydrocephalus

OBJECT

The hepatocyte growth factor (HGF), matrix metallopeptidase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1) are important cytokines with modulatory actions in the nervous system. In this study, we attempted to investigate the role and expression of HGF, MMP-9 and TGF-β1 in the cerebral tissue and cerebrospinal fluid (CSF) of adult rats with hydrocephalus induced via intraventricular kaolin injection.

METHODS

Adult male Sprague-Dawley rats were randomly divided into two groups: control group (n = 12) and experimental group (n = 20). Kaolin was injected into the lateral ventricle of experimental animals. Control rats underwent the same procedure but received sterile saline injection instead of kaolin. Magnetic resonance imaging was used to assess ventricle size. The CSF was studied by enzyme-linked immunosorbent assay and the excised brains were studied by reverse-transcription polymerase chain reaction and immunohistochemical analyses to measure the messenger RNA and protein expression level of HGF, MMP-9 and TGF-β1.

RESULTS

Hydrocephalus was induced in all the rats after kaolin injection into the lateral ventricle. After 2 weeks, the expressions of HGF, MMP-9 and TGF-β1 in the CSF and cerebral tissue were significantly increased in the experimental group compared with the control group.

CONCLUSIONS

This results indicated that HGF, MMP-9 and TGF-β1 may participate in the formation and prognosis of hydrocephalus after kaolin induction.

Effects of TRAP-1-like protein (TLP) gene on collagen synthesis induced by TGF-β/Smad signaling in human dermal fibroblasts

BACKGROUND

Hypertrophic scars are pathologic proliferations of the dermal skin layer resulting from excessive collagen deposition during the healing process of cutaneous wounds. Current research suggests that the TGF-β/Smad signaling pathway is closely associated with normal scar and hypertrophic scar formation. TRAP-1-like protein (TLP), a cytoplasmic protein, has been reported to efficiently regulate Smad2- and Smad3-dependent signal expression in the TGF-β pathway. The relationship between TLP and Type I/III collagen (Col I/III) synthesis explored in the present study provides an effective target for wound healing and gene therapy of hypertrophic scarring.

OBJECTIVE

To investigate the effects of TLP on collagen synthesis in human dermal fibroblasts.

METHODS

Lentiviral vectors encoding TLP was constructed to transfect fibroblasts derived from normal human skin. The expression of Col I/III and phosphorylation of Smad2 and Smad3 in fibroblasts were examined after TLP treatment. In addition, the comparison of TLP expression in normal skin tissues and in hypertrophic scar tissues was performed, and the effect of TLP on cell viability was analyzed by MTT assay.

RESULTS

TLP expression in hypertrophic scar tissue was markedly higher than in normal skin tissue. The Real Time PCR and Western blot test results both revealed that the synthesis of Col I/III was positively correlated with the expression of TLP. TLP also facilitate Smad2 phosphorylation while, conversely, inhibiting Smad3 phosphorylation. TLP may play a cooperative role, along with the cytokine TGF-β1, in improving the overall cell viability of skin fibroblasts.

CONCLUSIONS

TLP likely acts as a molecular modulator capable of altering the balance of Smad3- and Smad2-dependent signaling through regulation of phosphorylation, thus facilitating collagen synthesis in fibroblasts. Based on genetic variation in TLP levels in different tissues, these results suggest that TLP plays a key role in the process of TGF-β1/Smad3 signaling that contributes to wound healing and genesis of pathologic scars.

Matrix metalloproteinase-2 stimulates collagen-I expression through phosphorylation of focal adhesion kinase in rat cardiac fibroblasts

Collagen-I is thought to be the main component of the extracellular matrix in cardiac fibrosis, the accumulation of which occurs with excessive activation of matrix metalloproteinase-2 (MMP-2). MMP-2 degrades the extracellular matrix; however, the relative importance of MMP-2 to collagen-I synthesis in cardiac fibroblasts remains unclear. We investigated whether extracellular activation of MMP-2 regulates collagen-I synthesis and phosphorylation of focal adhesion kinase (FAK) in rat cardiac fibroblasts. Primary cultures of rat cardiac fibroblasts were incubated with purified active MMP-2 to determine whether extracellular MMP-2 affects collagen-I synthesis and FAK phosphorylation in cardiac fibroblasts. Exogenous MMP-2 significantly stimulated FAK (Tyr397) phosphorylation and induced collagen-I expression in a time-dependent manner. Simultaneous treatment with the FAK inhibitor PF573228 abolished exogenous MMP-2-enhanced FAK (Tyr397) phosphorylation and collagen-I expression. Cells were then stimulated with norepinephrine (NE) to investigate whether endogenous MMP-2 could also induce collagen-I expression through FAK (Tyr397) phosphorylation. NE-stimulated endogenous MMP-2 activation in conditioned medium was significantly attenuated by simultaneous treatment with the MMP inhibitor PD166793. Similarly, NE-induced FAK (Tyr397) phosphorylation and collagen-I expression were significantly inhibited by simultaneous treatment with PD166793 or PF573228. Furthermore, MMP-2 knockdown induced by small interfering RNA (siRNA) significantly abolished endogenous MMP-2 expression and activation. MMP-2 siRNA significantly abolished NE-induced FAK (Tyr397) phosphorylation and collagen-I expression. These findings suggest that the extracellular activation of MMP-2 accelerated collagen-I synthesis in rat cardiac fibroblasts and that FAK phosphorylation (Tyr397) plays a pivotal role in MMP-2-stimulated collagen-I synthesis.

N-type calcium channel inhibition with cilnidipine elicits glomerular podocyte protection independent of sympathetic nerve inhibition

We recently demonstrated that cilnidipine, an L/N-type calcium channel blocker, elicits protective effects against glomerular podocyte injury, in particular, in obese hypertensive rats that express the N-type calcium channel (N-CC). Since the N-CC is known to be expressed in sympathetic nerve endings, we evaluated the reno-protective effects of cilnidipine in innervated and denervated spontaneously hypertensive rats (SHR). Male SHR were uninephrectomized and fed 4% high-salt diet (HS-UNX-SHR). Animals were divided into groups, as follows, and observed from 9 to 27 weeks of age: 1) vehicle (n = 14), 2) vehicle plus renal-denervation (n = 15), 3) cilnidipine (50 mg/kg per day, p.o.; n = 10), and 4) cilnidipine plus renal-denervation (n = 15). Renal denervation attenuated elevations in blood pressure, but failed to suppress urinary protein excretion and podocyte injury in HS-UNX-SHR. Cilnidipine in both innervated and denervated HS-UNX-SHR similarly induced significant antihypertensive effects, as well as suppressing the urinary protein excretion and podocyte injury, compared to vehicle-treated HS-UNX-SHR. These data indicate that renal nerves have a limited contribution to the cilnidipine-induced reno-protective effects in HS-UNX-SHR.

Candesartan antagonizes pressure overload-evoked cardiac remodeling through Smad7 gene-dependent MMP-9 suppression

The present study was designed to investigate the underlying molecular mechanism for Angiotensin II type 1 receptor blockers (ARBs) mediated cardio-protection against pressure overload-induced cardiac remodeling with a focus on Smad7. ROCK-1, Smad3 and fibronectin expressions were increased in male C57BL/6 mice underwent transverse aortic constriction (TAC) for 2weeks. Treatment with Candesartan (2mg/kg per day) could effectively downregulate Smad3 and fibronectin accompanied by upregulating of Smad7. Further data showed that Candesartan inhibited TGF-β1 signal-induced epithelial-to-mesenchymal transition (EMT) through attenuating matrix metalloproteinases (MMP-9), such effect was abolished by knocking-down Smad7. Moreover, TAC for 2weeks caused increased collagen deposition, thickness of left ventricular anterior and posterior wall at end-diastole (LVAWD and LVPWD) and LVEF% reduction, which were reversed by treatment with Candesartan, but failed after knocking-down Smad7. In addition, LV dP/dt(max) and dP/dt(min) were increased by TAC for 2weeks, and treatment with Candesartan or Nifedipine effectively depressed the high levels of dP/dt(min) induced by TAC. However, only Candesartan-mediated protective role in improving cardiac function was suppressed by tail-vein injection of Smad7 siRNA. This study uncovered a novel role for ARBs in preventing pressure overload-induced cardiac remodeling via Smad7 upregulation, which suppressed MMP-9 expression and TGF-β1 signal-mediated EMT progress.

Regulation of Immunity via Multipotent Mesenchymal Stromal Cells

Immune cells responsible for inflammation development are involved in tissue damage caused by wounding and various pathologies. Control of immune cell activation could be of significant benefit for regenerative medicine and the treatment of patients with autoimmune and degenerative diseases. It is a proven fact that MCSs (multipotent mesenchymal stromal cells) are capable of suppressing immune responses via the inhibition of dendritic cell maturation and via the restraining of the T, B, and NK cell function in the course of autoimmune diseases and various forms of inflammation. MSCs can be isolated easily from almost every type of tissue or organ and subsequently expandedin vitro. These cells are self-renewable and can be differentiated into various cell types of mesenchymal lineage. The current review contains a collection and critical analysis of data regarding the molecular mechanisms responsible for cross-talk between immune cells and MSCs. Some of these mechanisms can be used for the development of new practical approaches for the treatment of autoimmune diseases.