Salidroside blocks the proliferation of pulmonary artery smooth muscle cells induced by platelet-derived growth factor-BB

Inhibitory Effect of PPARδ Agonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway

OBJECTIVE

This study aimed to investigate the effects of the peroxisome proliferator-activated receptor δ (PPARδ) agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells (PASMCs) induced by hypoxia, in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling.

METHODS

PASMCs were incubated with different concentrations of GW501516 (10, 30, 100 nmol/L) under the hypoxic condition. The proliferation was determined by a CCK-8 assay. The cell cycle progression was analyzed by flow cytometry. The expression of PPARδ, S phase kinase-associated protein 2 (Skp2), and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting. Then PASMCs were treated with 100 nmol/ L GW501516, 100 nmol/L mammalian target of rapamycin (mTOR) inhibitor rapamycin and/or 2 µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs.

RESULTS

The presented data demonstrated that hypoxia reduced the expression of PPARδ in an oxygen concentration- and time-dependent manner, and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle. In accordance with these findings, GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs. Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation, arresting the cell cycle, regulating the expression of Skp2 and p27, and inactivating mTOR in hypoxia-exposed PASMCs. Moreover, MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs.

CONCLUSION

GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

Traditional Chinese medicine monomers: Targeting pulmonary artery smooth muscle cells proliferation to treat pulmonary hypertension

Pulmonary hypertension (PH) is a complex multifactorial disease characterized by increased pulmonary vascular resistance and pulmonary vascular remodeling (PVR), with high morbidity, disability, and mortality. The abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is the main pathological change causing PVR. At present, clinical treatment drugs for PH are limited, which can only improve symptoms and reduce hospitalization but cannot delay disease progression and reduce survival rate. In recent years, numerous studies have shown that traditional Chinese medicine monomers (TCMs) inhibit excessive proliferation of PASMCs resulting in alleviating PVR through multiple channels and multiple targets, which has attracted more and more attention in the treatment of PH. In this paper, the experimental evidence of inhibiting PASMCs proliferation by TCMs was summarized to provide some directions for the future development of these mentioned TCMs as anti-PH drugs in clinical.

Salidroside in the Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is the commonest reason for chronic liver diseases in the world and is commonly related to the hepatic manifestation of the metabolic syndrome. Non-alcoholic steatohepatitis (NASH) is a deteriorating form of NAFLD, which can eventually develop into fibrosis, cirrhosis, and liver cancer. The reason for NAFLD/NASH development is complicated, such as liver lipid metabolism, oxidative stress, inflammatory response, apoptosis and autophagy, liver fibrosis and gut microbiota. Apart from bariatric surgery and lifestyle changes, officially approved drug therapy for NAFLD/NASH treatment is lacking. Salidroside (SDS) is a phenolic compound extensively distributed in the tubers of Rhodiola plants, which possesses many significant biological activities. This review summarized the related targets regulated by SDS in treating NAFLD/NASH. It is indicated that SDS could improve the status of NAFLD/NASH by ameliorating abnormal lipid metabolism, inhibiting oxidative stress, regulating apoptosis and autophagy, reducing inflammatory response, alleviating fibrosis and regulating gut microbiota. In conclusion, although the multiple bioactivities of SDS have been confirmed, the clinical data are inadequate and need to become the focus of attention in the later study.

Natural ingredients from Chinese materia medica for pulmonary hypertension

Pulmonary hypertension (PH) is a severe pathophysiological condition characterized by pulmonary artery remodeling and continuous increases in pulmonary artery pressure, which may eventually develop to right heart failure and death. Although newly discovered and incredible treatment strategies in recent years have improved the prognosis of PH, limited types of effective and economical drugs for PH still makes it as a life-threatening disease. Some drugs from Chinese materia medica (CMM) have been traditionally applied in the treatment of lung diseases. Accumulating evidence suggests active pharmaceutical ingredients (APIs) derived from those medicines brings promising future for the prevention and treatment of PH. In this review, we summarized the pharmacological effects of APIs derived from CMM which are potent in treating PH, so as to provide new thoughts for initial drug discovery and identification of potential therapeutic strategies in alternative medicine for PH.

A 1H NMR spectroscopic metabolomic study of the protective effects of irbesartan in a rat model of chronic mountain sickness

Chronic mountain sickness (CMS) is a significant pathology in most high-altitude regions globally, affecting the cardiopulmonary system and its mechanism is largely unknown. A metabonomic approach using ¹H nuclear magnetic resonance spectroscopy allows for detecting differential metabolites, which provides a global view and mechanisms during CMS development. In this study, we simulated a high-altitude environment to establish a rat model of CMS. Irbesartan was administered to CMS rats at three doses (6.75, 13.5, and 27 mg/kg) once a day for 15 days. HE staining and transmission electron microscopy were used to evaluate the effect of changes on the lung. Based on ¹H NMR spectra obtained from serum samples, partial least squares-discriminant analysis (PLS-DA) and its variant orthogonal PLS-DA (OPLS-DA) models were applied to distinguish the different groups. Histopathological sections showed that the alveolar structure was abnormal, inflammatory infiltration occurred in CMS rats, and CMS induced notable metabolic disorder according to the ¹H NMR result. However, irbesartan reversed the imbalanced metabolites via energy metabolism, amino acid metabolism, and taurine metabolism pathways, and its effect was also confirmed by the general signs and morphology of the lung. The results revealed that irbesartan as an effective therapeutic agent to improve CMS is warranted.

Salidroside: A review of its recent advances in synthetic pathways and pharmacological properties

Salidroside has been identified as one of the most potent compounds isolated from various Rhodiola plants, which have been used for a long time as adaptogens in traditional Chinese medicine. However, due to the severe growing environment of herbal medicine and large-scale excavation, the content of natural salidroside is extremely small. Most of the previous studies focused on herbal medicine, and there were few reviews on the synthesis of its main active ingredient salidroside. This paper presents different synthetic routes of salidroside to resolve the contradiction between supply and demand and lays the foundation for new drug research and development. Furthermore, emerging evidence indicates that salidroside, a promising environmentally-adapted drug with low toxicity and few side effects, possesses a wide spectrum of pharmacological properties, including activities on the cardiovascular system and central nervous system, anti-hypoxia, anti-fatigue and anti-aging activities, anticancer activity, anti-inflammatory activity, antioxidant activity, antivirus and immune stimulation activities, antidiabetic activity, anti-osteoporotic activity, and so on. Although the former researches have summarized the pharmacological effects of salidroside, focusing on the central nervous system, diabetes, and cancer, the overall pharmacological aspects of it have not been analyzed. This review highlights biological characteristics and mechanisms of action from 2009 to now as well as toxicological and pharmacokinetic data of the analyzed compound reported so far, with a view to providing a reference for further development and utilization of salidroside.

Antioxidant Effects of Salidroside in the Cardiovascular System

Cardiovascular disease is one of the main human health risks, and the incidence is increasing. Salidroside is an important bioactive component of Rhodiola rosea L., which is used to treat Alzheimer's disease, tumor, depression, and other diseases. Recent studies have shown that salidroside has therapeutic effects, to some degree, in cardiovascular diseases via an antioxidative mechanism. However, evidence-based clinical data supporting the effectiveness of salidroside in the treatment of cardiovascular diseases are limited. In this review, we discuss the effects of salidroside on cardiovascular risk factors and cardiovascular diseases and highlight potential antioxidant therapeutic strategies.

Natural plant products in treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe disease characterized by progressive remodeling of distal pulmonary arteries and persistent elevation of pulmonary vascular resistance (PVR), which leads to right ventricular dysfunction, heart failure, and eventually death. Although treatment responsiveness for this disease is improving, it continues to be a life-threatening condition. With the clinical efficacy of natural plant products being fully confirmed by years of practice, more and more recognition and attention have been obtained from the international pharmaceutical industry. Moreover, studies over the past decades have demonstrated that drugs derived from natural plants show unique advantages and broad application prospects in PAH treatment, not to mention the historical application of Chinese traditional medicine in cardiopulmonary diseases. In this review, we focus on summarizing natural plant compounds with therapeutic properties in PAH, according to the extracts, fractions, and pure compounds from plants into categories, hoping it to be helpful for basic research and clinical application.

Paeoniflorin blocks the proliferation of vascular smooth muscle cells induced by platelet‑derived growth factor‑BB through ROS mediated ERK1/2 and p38 signaling pathways

The proliferation of vascular smooth muscle cells (VSMCs) contributes to the development of vascular remodeling. In the present study, the effect of paeoniflorin (PAE) on the platelet derived growth factor-BB (PDGF-BB)-induced proliferation of primary cultured rat VSMCs and its molecular mechanism was investigated. The toxicity was determined by the try pan blue exclusion test. Cell proliferation was determined using a CCK-8 assay, DNA synthesis was assessed by measuring the incorporation of BrdU. Cell cycle progression was determined using PI staining and fluorescence-activated cell sorting. The level of intracellular reactive oxygen species (ROS) generation was assessed using dichlorodihydro fluorescein diacetate. mRNA expression was determined by reverse transcription quantitative polymerase chain reaction. Changes of p38, JNK, ERK1/2 signaling pathways were determined by western blot analysis. Cell migration was detected by scratch assay. PAE was demonstrated to significantly inhibit VSMC proliferation induced by PDGF-BB in a dose-and time-dependent manner without cell cytotoxicity. Thus, PAE blocked progression through the G0/G1 to Sphase of the cell cycle. Furthermore, inhibition of the cell cycle was associated with the inhibition of them RNA expression of cyclin D1, cyclin E, cyclin dependent kinase (CDK) 4 and CDK2 as well as with increased cyclin dependent kinase inhibitor 1A mRNA expression in PDGF-BB-stimulated VSMCs. Further studies showed that the beneficial effect of PAE on blocking VSMCs proliferation was related to the suppression of the ROS-mediated extra cellular signal-regulated kinase (ERK)1/2 and p38 signaling pathways, although PAE had no significant effect on the c-Jun N-terminal kinase signalling pathway. These results demonstrated that PAE suppressed PDGF-BB-induced VSMC proliferation through the ROS-mediated ERK1/2 and p38 signaling pathways, suggesting that it may be a feasible therapy for vascular remodelling diseases.

Salidroside contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic Goto-Kakizaki Rats by inhibition of L-type calcium channel in smooth muscle cells

BACKGROUND

Vascular disease is a common and often severe complication in diabetes mellitus. Hyperglycemia and hypertension are considered to be two of the leading risk factors for vascular complications in diabetic patients. However, few pharmacologic agents could provide a combinational therapy for controlling hyperglycemia and blood pressure in diabetic patients at the same time. Salidroside (SAL) is the major active ingredient derived from Rhodiola. Recently, it has been reported that SAL have an obvious hypoglycemic effect in diabetes and show a beneficial activity in diabetic vascular dysfunction. However, it remains unknown whether or not SAL treatment could directly reduce blood pressure in diabetes. Furthermore, it is not clear what is the molecular mechanism underlying the vascular protection of SAL treatment in diabetes.

METHODS

Male diabetic Goto-Kakizaki (GK) and non-diabetic control Wistar-Kyoto (WKY) rats were administrated with different dosages of SAL (50, 100 and 200 mg/kg/day) for 4 weeks. Contractile responsiveness of cerebral artery to KCl or 5-HT was investigated by Pressure Myograph System. The activity of Ca_L channel was investigated by recording whole-cell currents, assessing the expressions of Ca_L channel α_1C-subunit and its downstream kinase, MLCK, at protein or mRNA levels.

RESULTS

We showed that administration of 100 mg/kg/day SAL for 4 weeks not only lowered blood glucose, but also reduced blood pressure and alleviated cerebrovascular contractile activity in diabetic GK rats, which suggested that SAL treatment may provide a combinational therapy for lowering blood glucose and reducing blood pressure in diabetes at the same time. Furthermore, SAL treatment markedly inhibited the function and expression of Ca_L channel in cerebral VSMCs isolated from diabetic GK rats or when exposed to hyperglycemia condition, which may be the underlying mechanism responsible for the vascular protection of SAL in diabetes.

CONCLUSIONS

The present study provided evidences that SAL contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic GK rats by inhibition of Ca_L channel in smooth muscle cells, which may provide a novel approach to treat vascular complications in diabetic patients.

Effects of hesperetin on platelet-derived growth factor-BB-induced pulmonary artery smooth muscle cell proliferation

Hesperetin is a natural flavonoid, which has been reported to exert various biological activities and positive health effects on mammalian cells. The present study aimed to investigate the effects of hesperetin on the proliferation of primary cultured rat pulmonary artery smooth muscle cells (PASMCs), and to elucidate the possible underlying molecular mechanisms. The results of the present study indicated that hesperetin was able to inhibit the proliferation and DNA synthesis of platelet‑derived growth factor‑BB (PDGF‑BB)‑induced PASMCs in a dose‑ and time‑dependent manner, without exerting cell cytotoxicity. In addition, hesperetin blocked the progression of the cell cycle from G0/G1 to S phase, which was correlated with the decreased mRNA expression levels of cyclin D1, cyclin E, cyclin‑dependent kinase (CDK)2 and CDK4, and the increased mRNA expression levels of p27. Furthermore, the anti‑proliferative effects of hesperetin were associated with suppression of the AKT/glycogen synthase kinase (GSK)3β and p38 signaling pathway, but were not associated with the extracellular signal‑regulated kinases 1/2 and c‑Jun N‑terminal kinases signaling pathways. These results suggested that hesperetin may inhibit PDGFa‑BB‑induced PASMC proliferation via the AKT/GSK3β signaling pathway, and that it may possess therapeutic potential for the treatment of pulmonary vascular remodeling diseases.