De Novo Elastin Assembly Alleviates Development of Supravalvular Aortic Stenosis-Brief Report.

BACKGROUND: A series of incurable cardiovascular disorders arise due to improper formation of elastin during development. Supravalvular aortic stenosis (SVAS), resulting from a haploinsufficiency of ELN, is caused by improper stress sensing by medial vascular smooth muscle cells, leading to progressive luminal occlusion and heart failure. SVAS remains incurable, as current therapies do not address the root issue of defective elastin. METHODS: We use SVAS here as a model of vascular proliferative disease using both human induced pluripotent stem cell-derived vascular smooth muscle cells and developmental Eln+/- mouse models to establish de novo elastin assembly as a new therapeutic intervention. RESULTS: We demonstrate mitigation of vascular proliferative abnormalities following de novo extracellular elastin assembly through the addition of the polyphenol epigallocatechin gallate to SVAS human induced pluripotent stem cell-derived vascular smooth muscle cells and in utero to Eln+/- mice. CONCLUSIONS: We demonstrate de novo elastin deposition normalizes SVAS human induced pluripotent stem cell-derived vascular smooth muscle cell hyperproliferation and rescues hypertension and aortic mechanics in Eln+/- mice, providing critical preclinical findings for the future application of epigallocatechin gallate treatment in humans.

Doxorubicin induces cardiomyocyte pyroptosis via the TINCR-mediated posttranscriptional stabilization of NLR family pyrin domain containing 3.

AIMS: Doxorubicin (DOX), a widely used powerful chemotherapeutic component for cancer treatment, can give rise to severe cardiotoxicity that limits its clinical use. Pyroptosis is characterized by proinflammation and has been defined as a new type of programmed cell death in recent years. However, whether the DOX-induced cardiotoxicity is related to pyroptosis, and if so, which genes are involved in this process is largely unknown. In this study, we sought to identify the effect of DOX on cardiomyocyte pyroptosis and further reveal the underlying regulatory mechanism. METHODS AND RESULTS: In vitro and in vivo experiments showed that DOX treatment induced cardiomyocyte pyroptosis as evidenced by increased cell death and upregulated expression levels of NLR family pyrin domain containing 3 (NLRP3), caspase-3, IL-1ß, IL-18 and GMDSD-N. Inhibition of NLRP3 rescued the DOX-induced pyroptosis. qRT-PCR showed that TINCR lncRNA was upregulated by DOX treatment and knockdown of TINCR reversed the DOX-induced pyroptosis both in vitro and in vivo. Mechanistic investigations revealed that TINCR increased NLRP3 level via recruiting IGF2BP1 to enhance NLRP3 mRNA. And the effect of TINCR on cardiomyocyte pyroptosis was attenuated by the inhibition of NLRP3 or IGF2BP1. Finally, TINCR was not involved in DOX-induced pyroptosis in cancer cells. CONCLUSION: TINCR mediates the DOX-induced cardiotoxicity and pyroptosis in an IGF2BP1-dependent manner. Therefore, TINCR may serve as a promising therapeutic target to overcome the cardiotoxicity of chemotherapy for cancer therapy.

Yellow Wine Polyphenolic Compounds prevents Doxorubicin-induced cardiotoxicity through activation of the Nrf2 signalling pathway.

Doxorubicin (DOX) is considered as the major culprit in chemotherapy-induced cardiotoxicity. Yellow wine polyphenolic compounds (YWPC), which are full of polyphenols, have beneficial effects on cardiovascular disease. However, their role in DOX-induced cardiotoxicity is poorly understood. Due to their antioxidant property, we have been suggested that YWPC could prevent DOX-induced cardiotoxicity. In this study, we found that YWPC treatment (30 mg/kg/day) significantly improved DOX-induced cardiac hypertrophy and cardiac dysfunction. YWPC alleviated DOX-induced increase in oxidative stress levels, reduction in endogenous antioxidant enzyme activities and inflammatory response. Besides, administration of YWPC could prevent DOX-induced mitochondria-mediated cardiac apoptosis. Mechanistically, we found that YWPC attenuated DOX-induced reactive oxygen species (ROS) and down-regulation of transforming growth factor beta 1 (TGF-ß1)/smad3 pathway by promoting nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nucleus translocation in cultured H9C2 cardiomyocytes. Additionally, YWPC against DOX-induced TGF-ß1 up-regulation were abolished by Nrf2 knockdown. Further studies revealed that YWPC could inhibit DOX-induced cardiac fibrosis through inhibiting TGF-ß/smad3-mediated ECM synthesis. Collectively, our results revealed that YWPC might be effective in mitigating DOX-induced cardiotoxicity by Nrf2-dependent down-regulation of the TGF-ß/smad3 pathway.

The Role of Tauroursodeoxycholic Acid on Dedifferentiation of Vascular Smooth Muscle Cells by Modulation of Endoplasmic Reticulum Stress and as an Oral Drug Inhibiting In-Stent Restenosis.

PURPOSE: The role of endoplasmic reticulum (ER) stress in cardiovascular disease is now recognized. Tauroursodeoxycholic acid (TUDCA) is known to have cardiovascular protective effects by decreasing ER stress. This study aimed to assess the ability of TUDCA to decrease ER stress, inhibit dedifferentiation of vascular smooth muscle cells (VSMCs), and reduce in-stent restenosis. METHODS: The effect of TUDCA on dedifferentiation of VSMCs and ER stress was investigated in vitro using wound-healing assays, MTT assays, and western blotting. For in vivo studies, 18 rabbits were fed an atherogenic diet to induce atheroma formation. Bare metal stents (BMS), BMS+TUDCA or Firebird stents were implanted in the left common carotid artery. Rabbits were euthanized after 28 days and processed for scanning electron microscope (SEM), histological examination (HE), and immunohistochemistry. RESULTS: In vitro TUDCA (10-1000 µmol/L) treatment significantly inhibited platelet-derived growth factor (PDGF)-BB-induced proliferation and migration in VSMCs in a concentration-dependent manner and decreased ER stress markers (IRE1, XBP1, KLF4, and GRP78). In vivo, we confirmed no significant difference in neointimal coverage on three stents surfaces; neointimal was significantly lower with BMS+TUDCA (1.6 ± 0.2 mm2) compared with Firebird (1.90 ± 0.1 mm2) and BMS (2.3 ± 0.1 mm2). Percent stenosis was lowest for BMS+TUDCA, then Firebird, and was significantly higher with BMS (28 ± 4%, 35 ± 7%, 40 ± 1%; respectively; P < 0.001). TUDCA treatment decreased ER stress in the BMS+TUDCA group compared with BMS. CONCLUSIONS: TUDCA inhibited dedifferentiation of VSMCs by decreasing ER stress and reduced in-stent restenosis, possibly through downregulation of the IRE1/XBP1 signaling pathway.

Folic acid delays development of atherosclerosis in low-density lipoprotein receptor-deficient mice.

Many studies support the cardioprotective effects of folic acid (FA). We aimed to evaluate the utility of FA supplementation in preventing the development of atherosclerotic in low-density lipoprotein receptor-deficient (LDLR-/-) mice and to elucidate the molecular processes underlying this effect. LDLR-/- mice were randomly distributed into four groups: control group, HF group, HF + FA group and the HF + RAPA group. vascular smooth muscle cells (VSMCs) were divided into the following four groups: control group, PDGF group, PDGF + FA group and PDGF + FA + RAPA group. Blood lipid levels, oxidative stress and inflammatory cytokines were measured. Atherosclerosis severity was evaluated with oil red O staining. Haematoxylin and eosin (H&E) staining was used to assess atherosclerosis progression. Immunohistochemical staining was performed with antismooth muscle α-actin (α-SMA) antibodies and anti-osteopontin (OPN) antibodies that demonstrate VSMC dedifferentiation. The protein expression of α-SMA, OPN and mechanistic target of rapamycin (mTOR)/p70S6K signalling was detected by Western blot analysis. FA and rapamycin reduced serum levels of total cholesterol, triacylglycerol, LDL, inhibiting oxidative stress and the inflammatory response. Oil red O and H&E staining demonstrated that FA and rapamycin inhibited atherosclerosis. FA and rapamycin treatment inhibited VSMC dedifferentiation in vitro and in vivo, and FA and rapamycin attenuated the mTOR/p70S6K signalling pathway. Our findings suggest that FA attenuates atherosclerosis development and inhibits VSMC dedifferentiation in high-fat-fed LDLR-/- mice by reduced lipid levels and inhibiting oxidative stress and the inflammatory response through mTOR/p70S6K signalling pathway.

Recent advances in fluorescence imaging-guided photothermal therapy and photodynamic therapy for cancer: From near-infrared-I to near-infrared-II.

Phototherapy (including photothermal therapy, PTT; and photodynamic therapy, PDT) has been widely used for cancer treatment, but conventional PTT/PDT show limited therapeutic effects due to the lack of disease recognition ability. The integration of fluorescence imaging with PTT/PDT can reveal tumor locations in a real-time manner, holding great potential in early diagnosis and precision treatment of cancers. However, the traditional fluorescence imaging in the visible and near-infrared-I regions (VIS/NIR-I, 400-900 nm) might be interfered by the scattering and autofluorescence from tissues, leading to a low imaging resolution and high false positive rate. The deeper near-infrared-II (NIR-II, 1000-1700 nm) fluorescence imaging can address these interferences. Combining NIR-II fluorescence imaging with PTT/PDT can significantly improve the accuracy of tumor theranostics and minimize damages to normal tissues. This review summarized recent advances in tumor PTT/PDT and NIR-II fluorophores, especially discussed achievements, challenges and prospects around NIR-II fluorescence imaging-guided PTT/PDT for cancers.

Drug cross-linking electrospun fiber for effective infected wound healing.

The management of infected wounds is still an intractable challenge in clinic. Development of antibacterial wound dressing is of great practical significance for wound management. Herein, a natural-derived antibacterial drug, tannic acid (TA), was incorporated into the electrospun polyvinyl alcohol (PVA) fiber (TA/PVA fiber, 952 ± 40 nm in diameter). TA worked as a cross-linker via hydrogen bonding with PVA to improve the physicochemical properties of the fiber and to reach a sustained drug release (88% release of drug at 48 h). Improved mechanical property (0.8-1.2 MPa) and computational simulation validated the formation of the hydrogen bonds between TA and PVA. Moreover, the antibacterial and anti-inflammatory characteristics of TA laid the foundation for the application of TA/PVA fiber in repairing infected wounds. Meanwhile, in vitro studies proved the high hemocompatibility and cytocompatibility of TA/PVA fiber. Further in vivo animal investigation showed that the TA/PVA fiber promoted the repair of infected wound by inhibiting the bacterial growth, promoting granulation formation, and collagen matrix deposition, accelerating angiogenesis, and inducing M2 macrophage polarization within 14 days. All the data demonstrated that the TA cross-linked fiber would be a potent dressing for bacteria-infected wound healing.

Methacrylated gelatin shape-memorable cryogel subcutaneously delivers EPCs and aFGF for improved pressure ulcer repair in diabetic rat model.

Pressure ulcer (PU) in patients with diabetes mellitus (DM) is still a clinical intractable issue due to the complicated physiological characteristics by the prolonged high glucose level and impaired angiogenesis. The PU treatment includes surgical debridement, stem cell therapy and growth factors, leading to high cost and repeated professional involvement. Developing effective wound dressing combining the therapeutic cells and growth factors has become highly demanded. Herein, we reported the direct subcutaneous administration of endothelial progenitor cells (EPCs) and acid fibroblast growth factor (aFGF) with a shape-memorable methacrylated gelatin cryogel (EPCs/aFGF@GelMA) for the therapy of PU in rats with DM. This EPCs/aFGF@GelMA cryogel system presented microporous structure, elastic mechanical strength and enhanced cell migration property with controlled release of aFGF. Moreover, compared with EPCs/aFGF and GelMA alone, in vivo results showed that this EPCs/aFGF@GelMA system exhibited accelerated wound closure rate, enhanced granulation formation, collagen deposition as well as re-epithelization. Importantly, we found that the excellent positive performance of EPCs/aFGF@GelMA is due to its up-regulation of HIF-ɑ upon the wound site, modulating the microenvironment of wound site to initiate the impaired local angiogenesis. Collectively, this hybrid gelatin cryogels show great promise for biomedical applications, especially in tissue engineering and regenerative medicine.

Adhesive, injectable, and ROS-responsive hybrid polyvinyl alcohol (PVA) hydrogel co-delivers metformin and fibroblast growth factor 21 (FGF21) for enhanced diabetic wound repair.

As conventional treatments for diabetic wounds often fail to achieve rapid satisfactory healing, the development of effective strategies to accelerate diabetic wound repair is highly demanded. Herein, fibroblast growth factor 21 (FGF21) and metformin co-loaded multifunctional polyvinyl alcohol (PVA) hydrogel were fabricated for improved diabetic wound healing. The in vitro results proved that the hydrogel was adhesive and injectable, and that it could particularly scavenge reactive oxygen species (ROSs), while the in vivo data demonstrated that the hydrogel could promote angiogenesis by recruiting endothelial progenitor cells (EPCs) through upregulation of Ang-1. Both ROSs' removal and EPCs' recruitment finally resulted in enhanced diabetic wound healing. This work opens a strategy approach to diabetic wound management by combining biological macromolecules and small chemical molecules together using one promising environmental modulating drug delivery system.

Herpud1 deficiency could reduce amyloid-ß40 expression and thereby suppress homocysteine-induced atherosclerosis by blocking the JNK/AP1 pathway.

Homocysteine (Hcy) is considered an independent risk factor for various cardiovascular diseases including atherosclerosis which is associated with lipid metabolism, inflammation, and oxidative stress. Results from our previous study suggested that Hcy-induced atherosclerosis could be reversed by Herpud1 knockout which inhibits vascular smooth muscle cell (VSMC) phenotype switching. Here, we aim to investigate more precise mechanisms behind the improvement in Hcy-induced atherosclerosis. Amyloid-ß40 (Aß40), a vital protein in Alzheimer disease (AD), has been regarded as an important component in the atherosclerosis program in recent years due to the biological similarity between AD and atherosclerosis. Thus, we determined to assess the value of Aß40 in a Herpud1 knockout Hcy-induced atherosclerosis mouse model by measuring Aß40 expression in tissue and biomarkers of lipid metabolism, inflammation, and oxidative stress in serum. Additionally, since endothelial dysfunction plays a prominent role in atherosclerosis, we tested human umbilical vein endothelial cell (HUVEC) function following Herpud1 silencing in vitro and evaluated JNK/AP1 signaling activation in our models because of its close relationship with Aß40. As a result, our animal models showed that Herpud1 knockout reduced Aß40 expression, inflammation, and oxidative stress levels other than lipid metabolism and alleviated atherosclerosis via JNK/AP1 signaling inhibition. Similarly, our cell experiments implied that Hcy-induced Aß40 elevation and HUVEC dysfunction involving cell proliferation and apoptosis could be restored by Herpud1 silence through restraining JNK/AP1 pathway. Collectively, our study demonstrates that Herpud1 deficiency could reduce Aß40 expression, thereby suppressing Hcy-induced atherosclerosis by blocking the JNK/AP1 pathway. This may provide novel potential targets for atherosclerosis prevention or treatment.

Impaired autophagy mediates hyperhomocysteinemia-induced HA-VSMC phenotypic switching.

Hyperhomocysteinemia (HHcy) is a highly-related risk factor in vascular smooth muscle cell (VSMC) phenotypic modulation and atherosclerosis. Growing evidence indicated that autophagy is involved in pathological arterial changes. However, the risk mechanisms by which homocysteine and VSMC autophagy interact with cardiovascular disease are poorly understood. This study verified the homocysteine-responsive endoplasmic reticulum protein promotion of VSMC phenotypic switching, and the formation of atherosclerotic plaque in vitro. We found that impaired autophagy, as evidenced by decreased levels of MAP1LC3B II/MAP1LC3B I, has a vital role in HHcy-induced human aortic (HA)-VSMC phenotypic switching, with a decrease in contractile proteins (SM α-actin and calponin) and an increase in osteopontin. Knockdown of the essential autophagy gene Atg7 by small interfering RNA promoted HA-VSMC phenotypic switching, indicating that impaired autophagy induces phenotypic switching in these cells. HHcy co-treatment with rapamycin triggered autophagy, which alleviated HA-VSMC phenotypic switching. Finally, we found that Krüppel-like factor 4 (KLF4), a zinc-finger transcription factor for maintaining genomic stability by resisting oxidative stress and restoring autophagy, is closely involved in this process. HHcy clearly decreased KLF4 expression. KLF4-specific siRNA aggravated defective autophagy and phenotypic switching. Mechanistically, KLF4 regulated the HHcy-induced decrease in HA-VSMC autophagy via the m-TOR signaling pathway. In conclusion, these results demonstrated that the KLF4-dependent rapamycin signaling pathway is a novel mechanism underlying HA-VSMC phenotypic switching and is crucial for HHcy-induced HA-VSMCs with defective autophagy to accelerate early atherosclerosis.

A Carotenoid- and Poly-ß-Hydroxybutyrate-Free Mutant Strain of Sphingomonas elodea ATCC 31461 for the Commercial Production of Gellan.

Gellan gum is a microbial exopolysaccharide, produced after aerobic fermentation using the Gram-negative bacterium strain Sphingomonas elodea ATCC 31461. Due to its unique structure and excellent physical characteristics, gellan gum has a broad range of applications in food, pharmaceutical, and other industries where it is used for stabilizing, emulsifying, thickening, and suspending. During the fermentative production of gellan, strain ATCC 31461 also accumulates large amounts of the metabolic by-products yellow carotenoid pigments and poly-ß-hydroxybutyrate (PHB), which is decreasing the gellan production and increasing processing costs. A pigment PHB-free mutant was obtained by knocking out the phytoene desaturase gene (crtI) in the carotenoid biosynthetic pathway and the phaC gene, encoding a PHB synthase for the polymerization of PHB. Unfortunately, the double gene knockout mutant produced only 0.56 g liter-1 gellan. Furthermore, blocking PHB and carotenoid synthesis resulted in the accumulation of pyruvate, which reduced gellan production. To elevate gellan production, combined UV irradiation and ethyl methanesulfonate (EMS) mutagenesis treatment were used. A mutant strain with the same level of pyruvate as that of the wild-type strain and higher gellan production was isolated (1.35 g liter-1, 132.8% higher than the double gene knockout mutant and 14.4% higher than the wild-type strain ATCC 31461). In addition, a new gellan gum recovery method based on the new mutant strain was investigated, in which only 30% isopropanol was required, which is twice for the wild-type strains, and the performance of the final product was improved. Thus, the mutant strain could be an ideal strain for the commercial production of gellan.IMPORTANCE A carotenoid- and PHB-free double gene knockout strain mutant was constructed to simplify the purification steps normally involved in gellan production. However, the production of gellan gum was unexpectedly reduced. A mutant with 14.4% higher gellan production than that of the wild-type strain was obtained and isolated after employing UV and EMS combined mutagenesis. Based on this high-yield and low-impurity-producing mutant, a new recovery method requiring less organic solvent and fewer operating steps was developed. This method will effectively reduce the production costs and improve the economic benefits of large-scale gellan production.

Screening and enzymatic activity of high-efficiency gellan lyase producing bacteria Pseudoalteromonas hodoensis PE1.

Gellan is a widely used microbial polysaccharide and one of the more effective ways to expand its application value would be to investigate the mechanism of gellan lyase and to produce gellan oligosaccharide. In this study, efficient gellan degrading bacteria were screened. One of the strains with high efficient gellan degradation capacity was labeled PE1. Through physiological and biochemical analysis of 16S rDNA, the species was identified as Pseudoalteromonas hodoensis. The optimum conditions for enzymatic activity and how it was affected by metal ions were determined, and the results showed that the lyase activities were much higher than those of previously reported (about 20 times). The gellan degradation products were determined by thin-layer chromatography and the oligosaccharides were determined by high-efficiency liquid chromatography to analyze the action site of lyase. This study laid a solid foundation which elucidates the production and application of gellan oligosaccharides. Research highlights ● High efficiency gellan lyase producing bacteria ● Optimization of reaction conditions for gellan degradation ● Oligosaccharides were detected by TLC and HPLC to speculate the lyase action sites.

Knockdown of Herp alleviates hyperhomocysteinemia mediated atherosclerosis through the inhibition of vascular smooth muscle cell phenotype switching.

BACKGROUND: Phenotypic switching of vascular smooth muscle cells (VSMCs) plays a key role in atherosclerosis. We aimed to investigate whether Homocysteine-responsive endoplasmic reticulum protein (Herp) was involved in VSMC phenotypic switching and affected atheroprogression. METHODS: To assess the role of Herp in homocysteine (Hcy)-associated atherosclerosis, Herp-/- and LDLR-/- double knockout mice were generated and fed with a high methionine diet (HMD) to induce Hyperhomocysteinemia (HHcy). Atherosclerotic lesions, cholesterol homeostasis, endoplasmic reticulum (ER) stress activation, and the phenotype of VSMCs were assessed in vivo. We used siRNAs to knockdown Herp in cultured VSMCs to further validate our findings in vitro. RESULTS: HMD significantly activated the activating transcription factor 6 (ATF6)/Herp arm of ER stress in LDLR-/- mice, and induced the phenotypic switch of VSMCs, with the loss of contractile proteins (SMA and calponin) and an increase of OPN protein. Herp-/-/LDLR-/- mice developed reduced atherosclerotic lesions in the aortic sinus and the whole aorta when compared with LDLR-/- mice. However, Herp deficiency had no effect on diet-induced HHcy and hyperlipidemia. Inhibition of VSMC phenotypic switching, decreased proliferation and collagen accumulation were observed in Herp-/-/LDLR-/- mice when compared with LDLR-/- mice. In vitro experiments demonstrated that Hcy caused VSMC phenotypic switching, promoted cell proliferation and migration; this was reversed by Herp depletion. We achieved similar results via inhibition of ER stress using 4-phenylbutyric-acid (4-PBA) in Hcy-treated VSMCs. CONCLUSION: Herp deficiency inhibits the phenotypic switch of VSMCs and the development of atherosclerosis, thus providing novel insights into the role of Herp in atherogenesis.

[Effects of yellow wine polyphenols on cardiomyocyte apoptosis in diabetic cardiomyopathy rats].

OBJECTIVE: To investigate the effects of yellow wine polyphenols on the apoptosis of cardiomyocytes in diabetic cardiomyopathy rats. METHODS: Thirty SD rats were randomly divided into control group (Control), diabetic cardiomyopathy group (DCM) and diabetic cardiomyopathy treated with yellow wine polyphenols group (DCM+YWP). A single intraperitoneal injection of 65 mg/kg streptozotocin (STZ) was utilized to establish a rat model of DCM. The rats in control group were treated with citrate buffer at the same dose of a single intraperitoneal injection. DCM+YWP group were treated with 18 mg/kg Yellow wine polyphenols by ig after modeling. After treated for 12 weeks, the general condition of rats were observed. The cardiac structure and function of the rats were observed by Doppler echocardiography. The ultrastructure of myocardium were observed using electron microscopy. The inflammation index of myocardial tissue was detected by enzyme-linked immunosorbent assay (ELISA). The oxidative stress in myocardial tissues was assessed by oxidative stress detection kits. The expressions of Bax, Bcl-2 and Caspase-3 (cleaved) in myocardial were detected by Western blot. RESULTS: Compared with DCM group, the blood glucose levels and body weight of rats in the DCM+YWP group were not changed significantly. Echocardiography showed that left ventricular end-diastolic diameter, left ventricular end-systolic diameter were decreased (P<0.05), while fractional shortening and E/A ratio and Ea/Aa ratio were elevated (P<0.05). The levels of tumor factor-α(TNF-α), interleukin 1ß(IL-1ß) and interleukin 6(IL-6) in myocardium were decreased (P<0.05). The levels of oxidative stress malondiadehyde(MDA) were decreased and Superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) were increased in myocardial tissue (P<0.05). The expression levels of Bax and Caspase-3 (cleaved) protein in myocardium were decreased (P<0.05), and the expression of Bcl-2 protein was increased (P<0.05). CONCLUSIONS: Yellow wine polyphenols can improve the diabetic cardiomyopathy rat cardiac function, attenuates inflammation and oxidative stress in diabetic rats, inhibit the apoptosis of cardiomyocytes in diabetic cardiomyopathy.

Folic acid inhibits dedifferentiation of PDGF-BB-induced vascular smooth muscle cells by suppressing mTOR/P70S6K signaling.

OBJECTIVE: Folic acid (FA) supplementation reduces the risk of atherosclerosis and stroke. Phenotypic change from differentiated to dedifferentiated vascular smooth muscle cells (VSMCs) plays an important role in atherosclerosis development; however, the exact mechanisms remain unknown. This study aimed to assess whether FA through mammalian target of rapamycin (mTOR)/P70S6K signaling inhibits platelet derived growth factor (PDGF-BB) induced VSMC dedifferentiation. METHODS: VSMCs from primary cultures were identified by morphological observation and α-smooth muscle actin (α-SM-actin, α-SMA) immunocytochemistry. Then, VSMCs were induced by PDGF-BB and treated with varying FA concentrations. Rapamycin and MHY-1485 were used to inhibit or activate the mTOR/P70S6K pathway, respectively. Next, MTT, Transwell, and wound healing assays were employed to assess proliferation and migration of VSMCs. In addition, Western blotting was used to evaluate protein levels of α-SMA, calponin, osteopontin, mTOR, p-mTOR, P70S6K and p-P70S6K in VSMCs. RESULTS: VSMCs showed phenotypic alteration from differentiated to dedifferentiated cells in response to PDGF-BB. MTT, Transwell and wound healing assays showed that FA markedly inhibited proliferation and migration in PDGF-BB-induced VSMCs, in a time and concentration-dependent manner. FA treatment increased the expression levels of the contractile phenotype marker proteins α-SMA and calponin compared with VSMCs stimulated by PDGF-BB alone. Furthermore, FA significantly suppressed mTOR and P70S6K phosphorylation compared with PDGF-BB alone. Similar to FA, downregulation of mTOR signaling by rapamycin inhibited VSMC dedifferentiation. In contrast, upregulation of mTOR signaling by MHY-1485 reversed the FA-induced inhibition of VSMC dedifferentiation. CONCLUSION: Folic acid inhibits dedifferentiation of PDGF-BB-induced VSMCs by suppressing mTOR/P70S6K signaling.