Mitogenesis of vascular smooth muscle cell stimulated by platelet-derived growth factor-bb is inhibited by blocking of intracellular signaling by epigallocatechin-3-O-gallate

Assessing causal associations of blood counts and biochemical indicators with pulmonary arterial hypertension: a Mendelian randomization study and results from national health and nutrition examination survey 2003-2018

Background

Blood counts and biochemical markers are among the most common tests performed in hospitals and most readily accepted by patients, and are widely regarded as reliable biomarkers in the literature. The aim of this study was to assess the causal relationship between blood counts, biochemical indicators and pulmonary arterial hypertension (PAH).

Methods

A two-sample Mendelian randomization (MR) analysis was performed to assess the causal relationship between blood counts and biochemical indicators with PAH. The genome-wide association study (GWAS) for blood counts and biochemical indicators were obtained from the UK Biobank (UKBB), while the GWAS for PAH were sourced from the FinnGen Biobank. Inverse variance weighting (IVW) was used as the primary analysis method, supplemented by three sensitivity analyses to assess the robustness of the results. And we conducted an observational study using data from National Health and Nutrition Examination Survey (NHANES) 2003-2018 to verify the relationship.

Results

The MR analysis primarily using the IVW method revealed genetic variants of platelet count (OR=2.51, 95% CI 1.56-4.22, P<0.001), platelet crit(OR=1.87, 95% CI1.17-7.65, P=0.022), direct bilirubin (DBIL)(OR=1.71, 95%CI 1.18-2.47,P=0.004), insulin-like growth factor (IGF-1)(OR=0.51, 95% CI 0.27-0.96, P=0.038), Lipoprotein A (Lp(a))(OR=0.66, 95% CI 0.45-0.98, P=0.037) and total bilirubin (TBIL)(OR=0.51, 95% CI 0.27-0.96, P=0.038) were significantly associated with PAH. In NHANES, multivariate logistic regression analyses revealed a significant positive correlation between platelet count and volume and the risk of PAH, and a significant negative correlation between total bilirubin and PAH.

Conclusion

Our study reveals a causal relationship between blood counts, biochemical indicators and pulmonary arterial hypertension. These findings offer novel insights into the etiology and pathological mechanisms of PAH, and emphasizes the important value of these markers as potential targets for the prevention and treatment of PAH.

Rat bone marrow mesenchymal stem cells induced by rrPDGF-BB promotes bone regeneration during distraction osteogenesis

Background: In the clinical treatment of large bone defects, distraction osteogenesis can be used. However, some patients may suffer from poor bone regeneration, or even delayed healing or non-union. Problems with the aggregation and proliferation of primary osteoblasts, or problems with the differentiation of primary osteoblasts will lead to poor bone regeneration. Therefore, supplementing exogenous primary osteoblasts and growth factors when using distraction osteogenesis may be a treatment plan with great potential. Methods: Bone marrow mesenchymal stem cells (BMSCs) were extracted from rats and cultured. Subsequently, Recombinant Rat Platelet-derived Growth Factor BB (rrPDGF-BB) was used to induce bone marrow mesenchymal stem cells. At the same time, male adult rats were selected to make the right femoral distraction osteogenesis model. During the mineralization period, phosphate buffer salt solution (control group), non-induction bone marrow mesenchymal stem cells (group 1) and recombinant rat platelet-derived growth factor BB intervened bone marrow mesenchymal stem cells (group 2) were injected into the distraction areas of each group. Then, the experimental results were evaluated with imaging and histology. Statistical analysis of the data showed that the difference was statistically significant if p < 0.05. Results: After intervention with recombinant rat platelet-derived growth factor BB on bone marrow mesenchymal stem cells, the cell morphology changed into a thin strip. After the cells were injected in the mineralization period, the samples showed that the callus in group 2 had greater hardness and the color close to the normal bone tissue; X-ray examination showed that there were more new callus in the distraction space of group 2; Micro-CT examination showed that there were more new bone tissues in group 2; Micro-CT data at week eight showed that the tissue volume, bone volume, percent bone volume, bone trabecular thickness, bone trabecular number and bone mineral density in group 2 were the largest, and the bone trabecular separation in group 2 was the smallest. There was a statistical difference between the groups (p < 0.05); HE staining confirmed that group 2 formed more blood vessels and chondrocytes earlier than the control group. At 8 weeks, the bone marrow cavity of group 2 was obvious, and some of them had been fused. Conclusion: The study confirmed that injecting bone marrow mesenchymal stem cellsBB into the distraction space of rats can promote the formation of new bone in the distraction area and promote the healing of distraction osteogenesis.

Therapeutic Effects of Green Tea Polyphenol (‒)-Epigallocatechin-3-Gallate (EGCG) in Relation to Molecular Pathways Controlling Inflammation, Oxidative Stress, and Apoptosis

(‒)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea. Thanks to multiple interactions with cell surface receptors, intracellular signaling pathways, and nuclear transcription factors, EGCG possesses a wide variety of anti-inflammatory, antioxidant, antifibrotic, anti-remodelation, and tissue-protective properties which may be useful in the treatment of various diseases, particularly in cancer, and neurological, cardiovascular, respiratory, and metabolic disorders. This article reviews current information on the biological effects of EGCG in the above-mentioned disorders in relation to molecular pathways controlling inflammation, oxidative stress, and cell apoptosis.

A microRNA‑17‑5p/homeobox B13 axis participates in the phenotypic modulation of vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs) serve a decisive role in intimal hyperplasia, a common pathophysiological process that leads to numerous vascular disorders. The present study aimed to investigate the unknown mechanisms underlying VSMC phenotypic modulation and identified a novel microRNA (miRNA/miR)‑17‑5p/homeobox B13 (HOXB13) axis involved in the phenotypic switching, proliferation and migration of VSMCs. VSMCs were isolated from the thoracic aorta of Sprague‑Dawley rats, cell proliferation was determined by Cell Counting Kit‑8 (CCK‑8) assay, cell migration was examined by Transwell migration assay and gene expression was detected using reverse transcription‑quantitative PCR and western blot analyses. It was firstly found that incubation with platelet‑derived growth factor‑BB (PDGF‑BB) recombinant protein resulted in a significant increase in HOXB13 expression in VSMCs. Using multiple miRNA prediction tools, miR‑17‑5p was identified as a potential regulator for HOXB13, since it had a 7‑base perfect binding site and a 5‑base imperfect binding site with the 3'‑untranslated region of HOXB13 mRNA, and these sequences were highly conserved across species. The regulatory effect of miR‑17‑5p on HOXB13 was validated using luciferase reporter assays. The expression level of miR‑17‑5p was increased in VSMCs under PDGF‑BB stimulation, and was negatively correlated with HOXB13 mRNA and protein expression. Moreover, the miR‑17‑5p mimics significantly inhibited the proliferation and migration of VSMCs, while antagomiR‑17‑5p showed the opposite effects, which could be abolished by HOXB13 knockdown. The miR‑17‑5p/HOXB13 axis also regulated the expression levels of the markers of differentiated VSMCs (α‑smooth muscle actin, transgelin and smoothelin), proliferating cell nuclear antigen and cell migration proteins, including MMP‑2 and ‑9. In conclusion, the present study demonstrated that miR‑17‑5p inhibited the phenotypic modulation VSMCs stimulated by PDGF‑BB by downregulating HOXB13, indicating that these factors may be potential therapeutic targets for intimal hyperplasia.

The effects of a biodegradable Mg-based alloy on the function of VSMCs via immunoregulation of macrophages through Mg-induced responses

Background

Restenosis is one of the worst side effects of percutaneous coronary intervention (PCI) due to neointima formation resulting from the excessive proliferation and migration of vascular smooth muscle cells (VSMCs) and continuous inflammation. Biodegradable Mg-based alloy is a promising candidate material because of its good mechanical properties and biocompatibility, and biodegradation of cardiovascular stents. Although studies have shown reduced neointima formation after Mg-based CVS implantation in vivo, these findings were inconsistent with in vitro studies, demonstrating magnesium-mediated promotion of the proliferation and migration of VSMCs. Given the vital role of activated macrophage-driven inflammation in neointima formation, along with the well-demonstrated crosstalk between macrophages and VSMCs, we investigated the interactions of a biodegradable Mg-Nd-Zn-Zr alloy (denoted JDBM), which is especially important for cardiovascular stents, with VSMCs via macrophages.

Methods

JDBM extracts and MgCl₂ solutions were prepared to study their effect on macrophages. To study the effects of the JDBM extracts and MgCl₂ solutions on the function of VSMCs via immunoregulation of macrophages, conditioned media (CM) obtained from macrophages was used to establish a VSMC-macrophage indirect coculture system.

Results

Our results showed that both JDBM extracts and MgCl₂ solutions significantly attenuated the inflammatory response stimulated by lipopolysaccharide (LPS)-activated macrophages and converted macrophages into M2-type cells. In addition, JDBM extracts and MgCl₂ solutions significantly decreased the expression of genes related to VSMC phenotypic switching, migration, and proliferation in macrophages. Furthermore, the proliferation, migration, and proinflammatory phenotypic switching of VSMCs were significantly inhibited when the cells were incubated with CMs from macrophages treated with LPS + extracts or LPS + MgCl₂ solutions.

Conclusions

Taken together, our results suggested that the magnesium in the JDBM extract could affect the functions of VSMCs through macrophage-mediated immunoregulation, inhibiting smooth muscle hyperproliferation to suppress restenosis after implantation of a biodegradable Mg-based stent.

Phytotherapy for Cardiovascular Disease: A Bench-to-Bedside Approach

At present, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and global trends suggest that this panorama will persist or worsen in the near future. Thus, optimization of treatment strategies and the introduction of novel therapeutic alternatives for CVD represent key objectives in contemporary biomedical research. In recent years, phytotherapy-defined as the therapeutic use of whole or minimally modified plant components-has ignited large scientific interest, with a resurgence of abundant investigation on a wide array of medicinal herbs (MH) for CVD and other conditions. Numerous MH have been observed to intervene in the pathophysiology of CVD via a myriad of molecular mechanisms, including antiinflammatory, anti-oxidant, and other beneficial properties, which translate into the amelioration of three essential aspects of the pathogenesis of CVD: Dyslipidemia, atherosclerosis, and hypertension. Although the preclinical data in this scenario is very rich, the true clinical impact of MH and their purported mechanisms of action is less clear, as large-scale robust research in this regard is in relatively early stages and faces important methodological challenges. This review offers a comprehensive look at the most prominent preclinical and clinical evidence currently available concerning the use of MH in the treatment of CVD from a bench-to-bedside approach.

Neointimal Hyperplasia after Carotid Transection and Anastomosis Surgery is Associated with Degradation of Decorin and Platelet Derived Growth Factor Signaling

Objective

Intimal hyperplasia (IH) is the expansion of the vascular intimal region after intervention, which can lead to stenosis and eventual failure of vascular grafts or interventional procedures such as angioplasty or stent placement. Our goals were to investigate the development of IH in a rabbit open surgical model and to evaluate the associated pathophysiologic processes involving decorin and the platelet-derived growth factor-BB/platelet-derived growth factor receptor-β/mitogen-activated protein kinase (PDGF-BB/PDGFR-β/MAPK) pathway.

Methods

We conducted carotid transection and primary anastomosis on five New Zealand white rabbits to induce IH and examined the associated pathophysiologic changes. Tissue was obtained for histological and protein analysis on postoperative day 21 using the contralateral vessel as a control. Intimal medial thickness (IMT) was calculated to measure IH and compared with the unoperated side. Western blot analysis was performed on tissue lysates to determine the expression of decorin core protein, PDGF-BB, PDGFR-β, and phosphorylated-MAPK (ph-MAPK). Immunofluorescence microscopy was used to assess tissue distribution of matrix metalloproteinase-2 (MMP-2) and ph-PDGFR-β.

Results

Bilateral carotid arteries were harvested on postoperative day 21. We compared the IMT in operated with unoperated specimens. IMT was significantly elevated in operated arteries vs unoperated arteries in all five animals (148.6 μm ± 9.09 vs 103.40 μm ± 7.08; 135.2 μm ± 8.30 vs 92.40 μm ± 2.35; 203.1 μm ± 30.23 vs 104.00 μm ± 4.52; 236.2 μm ± 27.22 vs 141.50 μm ± 9.95; 226.9 μm ± 11.12 vs 98.8 μm ± 3.78). Western blot analysis revealed degradation of decorin protein in the operated tissue, including loss of a 50 kDa band and the appearance of a cleaved fragment at 10 kDa. Decorin and MMP-2 were observed, via immunofluorescence microscopy, in the neointima of the operated vessels. Western blot analysis also revealed increased PDGF-BB, PDGFR-β, and ph-MAPK levels in operated tissue. Immunofluorescent staining for ph-PDGFR-β primarily localized to the neointima, indicating increased signaling through PDGF in this region.

Conclusions

Carotid transection and primary reanastomosis in rabbits induced IH that was associated with MMP-2 activation, degradation of decorin, and activation of the PDGF/PDGFR-β/MAPK pathway. The findings in this study should lead to further mechanistic evaluation of these pathways to better understand the potential to modify the intimal hyperplastic response to surgery. (JVS–Vascular Science 2020;2:2-12.)

Clinical Relevance

Intimal hyperplasia remains a significant challenge to the vascular surgeon in open and interventional procedures. Basic science studies have made headway into understanding the process, but this has not translated into many therapeutic options particularly for primary prevention after a procedure. Decorin is gaining popularity as an important mediator of various pathophysiologic processes involving the extracellular matrix. We sought to determine the possible role of decorin in the development of neointimal hyperplasia in an open surgical model. This study provides a replicable model for the development of intimal hyperplasia and potential therapeutic targets going forward.

Molecular regulation of vascular smooth muscle cell phenotype switching by trophoblast cells at the maternal-fetal interface

INTRODUCTION

Establishment of hemochorial placenta is associated with development and remodelling of uterine vasculature at the maternal fetal interface. This results in calibration of high resistance uterine arteries to flaccid low resistance vessels resulting in increased blood flow to the placenta and fetus in humans and rodents. Mechanisms underlying these remodelling events are poorly understood. In this report, we examine regulation of vascular remodelling using vascular smooth muscle cell (VSMC) phenotype switching as a primary parameter.

METHODS

Cellular dynamics was assessed by Immunofluorescence, qRT-PCR, western blotting in timed pregnant rat tissue. In vitro co-culture of trophoblast cells with vascular smooth muscle cells was used to understand regulation mechanism.

RESULTS

Analysis of cellular dynamics on days 13.5, 16.5 and 19.5 of gestation in the rat metrial gland, the entry point of uterine arteries, revealed that invasion of trophoblast cells preceded disappearance of VSMC α-SMA, a contractile state marker. Co-culture of VSMCs with trophoblast cells in vitro recapitulated trophoblast-induced de-differentiation of VSMCs in vivo. Interestingly, co-culturing with trophoblast cells activated PDGFRβ signalling in VSMCs, an effect mediated by secreted PDGF-BB from trophoblast cells. Trophoblast cells failed to elicit its effect on VSMC de-differentiation upon inhibition of PDGFRβ signalling using a selective inhibitor. Moreover, co-culturing with trophoblast cells also led to substantial increase in Akt activation and a modest increase in Erk phosphorylation in VSMCs and this effect was abolished by PDGFRβ inhibition.

DISCUSSION

Our results highlight that trophoblast cells direct VSMC phenotype switching and trophoblast derived PDGF-BB is one of the modulator.

Epigallocatechin-3-Gallate Toxicity in Children: A Potential and Current Toxicological Event in the Differential Diagnosis With Virus-Triggered Fulminant Hepatic Failure

The use of nutraceuticals is considerably increasing worldwide with a demand for organic and clean foods in the last two decades, which is probably incomparable with other periods of our civilization. The consistent application of nutraceuticals and so-called "superfood" may have remarkable effects on the prevention of several chronic diseases, including cancer. Moreover, the increased rate of overweight and obesity in Western countries does not spare childhood and youth, and the number of parents using natural remedies for preventing pediatric illness is vastly increasing worldwide. However, the overwhelming effects on diseases often overshadow the side effects of such nutrition, particularly in societies without millennial experience with botanicals and natural elements. Thus, the final result may be disastrous for some individuals. The liver is the most important and conspicuous target organ of numerous molecular compounds, and the cell damage is particularly striking on the infantile and pediatric liver due to the immaturity of the hepatocytes. Here, we target some generic data on fulminant hepatic failure, the benefits, and toxicity of epigallocatechin-3-gallate, which is one of the major components of green tea, and the histopathology of the "green-tea"-associated liver disease.

The Effects of Platelet-Derived Growth Factor-BB on Bone Marrow Stromal Cell-Mediated Vascularized Bone Regeneration

Regenerative medicine for bone tissue mainly depends on efficient recruitment of endogenous or transplanted stem cells to guide bone regeneration. Platelet-derived growth factor (PDGF) is a functional factor that has been widely used in tissue regeneration and repair. However, the short half-life of PDGF limits its efficacy, and the mechanism by which PDGF regulates stem cell-based bone regeneration still needs to be elucidated. In this study, we established genetically modified PDGF-B-overexpressing bone marrow stromal cells (BMSCs) using a lentiviral vector and then explored the mechanism by which PDGF-BB regulates BMSC-based vascularized bone regeneration. Our results demonstrated that PDGF-BB increased osteogenic differentiation but inhibited adipogenic differentiation of BMSCs via the extracellular signal-related kinase 1/2 (ERK1/2) signaling pathway. In addition, secreted PDGF-BB significantly enhanced human umbilical vein endothelial cell (HUVEC) migration and angiogenesis via the phosphatidylinositol 3 kinase (PI3K)/AKT and ERK1/2 signaling pathways. We evaluated the effect of PDGF-B-modified BMSCs on bone regeneration using a critical-sized rat calvarial defect model. Radiography, micro-CT, and histological analyses revealed that PDGF-BB overexpression improved BMSC-mediated angiogenesis and osteogenesis during bone regeneration. These results suggest that PDGF-BB facilitates BMSC-based bone regeneration by enhancing the osteogenic and angiogenic abilities of BMSCs.

Anti-atherosclerotic plants which modulate the phenotype of vascular smooth muscle cells

BACKGROUND

Cardiovascular disease (CVD) remains the leading cause of global death, with atherosclerosis being a major contributor to this mortality. Several mechanisms are implicated in the pathogenesis of this disease. A key element in the development and progression of atherosclerotic lesions is the phenotype of vascular smooth muscle cells. Under pathophysiologic conditions such as injury, these cells switch from a contractile to a synthetic phenotype that often possesses high proliferative and migratory capacities.

PURPOSE

Despite major advances made in the management and treatment of atherosclerosis, mortality associated with this disease remains high. This mandates that other approaches be sought. Herbal medicine, especially for the treatment of CVD, has been gaining more attention in recent years. This is in no small part due to the evidence-based values associated with the consumption of many plants as well as the relatively cheaper prices, easier access and conventional folk medicine "inherited" over generations. Sections: In this review, we provide a brief introduction about the pathogenesis of atherosclerosis then we highlight the role of vascular smooth muscle cells in this disease, especially when a phenotypic switch of these cells arises. We then thoroughly discuss the various plants that show potentially beneficial effects as anti-atherosclerotic, with prime attention given to herbs and plants that inhibit the phenotypic switch of vascular smooth muscle cells.

CONCLUSION

Accumulating evidence provides the justification for the use of botanicals in the treatment or prevention of atherosclerosis. However, further studies, especially clinical ones, are warranted to better define several pharmacological parameters of these herbs, such as toxicity, tolerability, and efficacy.

Green tea (-)-epigallocatechin gallate inhibits the growth of human villous trophoblasts via the ERK, p38, AMP-activated protein kinase, and protein kinase B pathways

Green tea catechins, especially (-)-epigallocatechin gallate (EGCG), have been reported to circulate in the placenta of animals and blood of humans after consumption. Whether EGCG regulates activity of human villous trophoblasts (HVT) is unknown. This study investigated the pathways involved in EGCG modulation of trophoblast mitogenesis. EGCG inhibited trophoblast proliferation in a dose-dependent and time-dependent manner, as indicated by the number of cells and incorporation of bromodeoxyuridine (BrdU). EGCG was more effective than other green tea catechins in inhibiting cell growth. EGCG also increased the phosphorylation of the MAPK pathway proteins, ERK1/2, and p38, but not JNK. Furthermore, EGCG had no effects on the total amounts of ERK1/2, p38 MAPK, and JNK proteins. This suggests that EGCG selectively affects particular MAPK subfamilies. Pretreatment with specific inhibitors of ERK1/2, p38 MAPK, and AMP-activated protein kinase (AMPK) antagonized EGCG-induced decreases in both cell number and BrdU incorporation. These inhibitors also blocked EGCG-induced increases in the levels of phospho-ERK1/2, phospho-p38, and phospho-AMPK proteins, respectively. Moreover, EGCG was similar to the phosphatidylinositol 3-kinase inhibitors wortmannin and LY-294002 to decrease protein kinase B (AKT) phosphorylation, cell number, and BrdU incorporation. These data imply that EGCG inhibits the growth of HVT through the ERK, p38, AMPK, and AKT pathways.

In vitro toxicity of epigallocatechin gallate in rat liver mitochondria and hepatocytes

Epigallocatechin-3-gallate (EGCG) is the main compound of green tea with well-described antioxidant, anti-inflammatory, and tumor-suppressing properties. However, EGCG at high doses was reported to cause liver injury. In this study, we evaluated the effect of EGCG on primary culture of rat hepatocytes and on rat liver mitochondria in permeabilized hepatocytes. The 24-hour incubation with EGCG in concentrations of 10 μmol/L and higher led to signs of cellular injury and to a decrease in hepatocyte functions. The effect of EGCG on the formation of reactive oxygen species (ROS) was biphasic. While low doses of EGCG decreased ROS production, the highest tested dose induced a significant increase in ROS formation. Furthermore, we observed a decline in mitochondrial membrane potential in cells exposed to EGCG when compared to control cells. In permeabilized hepatocytes, EGCG caused damage of the outer mitochondrial membrane and an uncoupling of oxidative phosphorylation. EGCG in concentrations lower than 10 μmol/L was recognized as safe for hepatocytes in vitro.