Paeonol regulates hypoxia-induced proliferation of pulmonary artery smooth muscle cells via EKR 1/2 signalling

Targeting gut microbiota and immune crosstalk: potential mechanisms of natural products in the treatment of atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory reaction that primarily affects large and medium-sized arteries. It is a major cause of cardiovascular disease and peripheral arterial occlusive disease. The pathogenesis of AS involves specific structural and functional alterations in various populations of vascular cells at different stages of the disease. The immune response is involved throughout the entire developmental stage of AS, and targeting immune cells presents a promising avenue for its treatment. Over the past 2 decades, studies have shown that gut microbiota (GM) and its metabolites, such as trimethylamine-N-oxide, have a significant impact on the progression of AS. Interestingly, it has also been reported that there are complex mechanisms of action between GM and their metabolites, immune responses, and natural products that can have an impact on AS. GM and its metabolites regulate the functional expression of immune cells and have potential impacts on AS. Natural products have a wide range of health properties, and researchers are increasingly focusing on their role in AS. Now, there is compelling evidence that natural products provide an alternative approach to improving immune function in the AS microenvironment by modulating the GM. Natural product metabolites such as resveratrol, berberine, curcumin, and quercetin may improve the intestinal microenvironment by modulating the relative abundance of GM, which in turn influences the accumulation of GM metabolites. Natural products can delay the progression of AS by regulating the metabolism of GM, inhibiting the migration of monocytes and macrophages, promoting the polarization of the M2 phenotype of macrophages, down-regulating the level of inflammatory factors, regulating the balance of Treg/Th17, and inhibiting the formation of foam cells. Based on the above, we describe recent advances in the use of natural products that target GM and immune cells crosstalk to treat AS, which may bring some insights to guide the treatment of AS.

Intrapulmonary arterial contraction assay reveals region-specific deregulation of vasoreactivity to lung injuries

Intrapulmonary arteries located in the proximal lung differ from those in the distal lung in size, cellular composition, and the surrounding microenvironment. However, whether these structural variations lead to region-specific regulation of vasoreactivity in homeostasis and following injury is unknown. Herein, we employ a two-step method of precision-cut lung slice (PCLS) preparation, which maintains almost intact intrapulmonary arteries, to assess contractile and relaxation responses of proximal preacinar arteries (PaAs) and distal intraacinar arteries (IaAs) in mice. We found that PaAs exhibited robust vasoconstriction in response to contractile agonists and significant nitric oxide (NO)-induced vasodilation. In comparison, IaAs were less contractile and displayed a greater relaxation response to NO. Furthermore, in a mouse model of pulmonary arterial hypertension (PAH) induced by chronic exposure to ovalbumin (OVA) allergen and hypoxia (OVA-HX), IaAs demonstrated a reduced vasocontraction despite vascular wall thickening with the emergence of new αSMA+ cells coexpressing markers of pericytes. In contrast, PaAs became hypercontractile and less responsive to NO. The reduction in relaxation of PaAs was associated with decreased expression of protein kinase G, a key component of the NO pathway, following chronic OVA-HX exposure. Taken together, the PCLS prepared using the modified preparation method enables functional evaluation of pulmonary arteries in different anatomical locations and reveals region-specific mechanisms underlying the pathophysiology of PAH in a mouse model.NEW & NOTEWORTHY Utilizing mouse precision-cut lung slices with preserved intrapulmonary vessels, we demonstrated a location-dependent structural and contractile regulation of pulmonary arteries in health and on noxious stimulations. For instance, chronic ovalbumin and hypoxic exposure increased pulmonary arterial pressure (PAH) by remodeling intraacinar arterioles to reduce vascular wall compliance while enhancing vasoconstriction in proximal preacinar arteries. These findings suggest region-specific mechanisms and therapeutic targets for pulmonary vascular diseases such as PAH.

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.

Paeonol attenuates heart failure induced by transverse aortic constriction via ERK1/2 signalling

CONTEXT

Paeonol (PAE) is the main phytochemical from Cortex Moutan. Its main pharmacological effects are anti-inflammatory and antioxidant, but its cardioprotective effect is unclear.

OBJECTIVE

The study investigates the effects and underlying mechanisms of PAE on transverse aortic constriction (TAC)-induced heart failure (HF) in mice.

MATERIALS AND METHODS

C57BL/6 mice were randomly divided into five groups: sham, TAC, PAE10 (TAC + PAE 10 mg/kg), PAE20 (TAC + PAE 20 mg/kg) and PAE 50 (TAC + PAE 50 mg/kg). Paeonol was intragastrically administered to mice for 4 weeks. Mice were anaesthetized with pentobarbital sodium and underwent cardiac echocardiography using echocardiography system. Serum levels of atrial natriuretic peptide (ANP), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA). Myocardial apoptosis was detected with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) staining. Haematoxylin-eosin (H&E) and Masson's staining were used for histopathological evaluation. Western and quantitative real-time PCR (qRT-PCR) were performed to detect levels of apoptosis and fibrosis-related proteins.

RESULTS

Echocardiography showed PAE improved cardiac function (LVEF: TAC, 52.3±6.8%; PAE20, 65.8±3.6%; PAE50, 71.4±2.5%) and H&E staining showed PAE alleviated myocardial injury (TAC: 1170.3 ± 134.6 μm²; PAE50: 576.0 ± 53.5 μm²). Western and qRT-PCR results showed that PAE down-regulated the levels of ANP, BNP and α-MHC. In addition, TUNEL and western results showed PAE significantly inhibited apoptosis. Masson and western results showed PAE inhibited cardiac hypertrophy. Western results showed the ERK1/2/JNK pathway could be inhibited by PAE.

DISCUSSION AND CONCLUSIONS

Paeonol regulates ERK1/2/JNK to improve cardiac function, which provides theoretical support for the extensive clinical treatment of HF.

A Comparative Transcriptome Analysis Reveals the Molecular Mechanisms That Underlie Somatic Embryogenesis in Peaonia ostii ‘Fengdan’

Low propagation rate is the primary problem that limits industry development of tree peony. In this study, a highly efficient regeneration system for tree peony using somatic embryogenesis (SE) was established. The transcriptomes of zygotic embryo explants (S0), non-embryonic callus (S1), embryonic callus (S2), somatic embryos (S3), and regenerated shoots (S4) were analyzed to determine the regulatory mechanisms that underlie SE in tree peony. The differentially expressed genes (DEGs) were identified in the pairwise comparisons of S1-vs-S2 and S1-vs-S3, respectively. The enriched DEGs were primarily involved in hormone signal transduction, stress response and the nucleus (epigenetic modifications). The results indicated that cell division, particularly asymmetric cell division, was enhanced in S3. Moreover, the genes implicated in cell fate determination played central roles in S3. Hormone signal pathways work in concert with epigenetic modifications and stress responses to regulate SE. SERK, WOX9, BBM, FUS3, CUC, and WUS were characterized as the molecular markers for tree peony SE. To our knowledge, this is the first study of the SE of tree peony using transcriptome sequencing. These results will improve our understanding of the molecular mechanisms that underly SE in tree peony and will benefit the propagation and genetic engineering of this plant.

A review on therapeutical potential of paeonol in atherosclerosis

The morbidity and mortality of atherosclerotic cardiovascular disease (ASCVD) is increasing year by year. Cortex Moutan is a traditional Chinese medicinal herb that has been widely used for thousands of years to treat a wide variety of diseases in Eastern countries due to its heat-clearing and detoxifying effects. Paeonol is a bioactive monomer extracted from Cortex Moutan, which has anti-atherosclerotic effects. In this article, we reviewed the pharmacological effects of paeonol against experimental atherosclerosis, as well as its protective effects on vascular endothelial cells, smooth muscle cells, macrophages, platelets, and other important cell types. The pleiotropic effects of paeonol in atherosclerosis suggest that it can be a promising therapeutic agent for atherosclerosis and its complications. Large-scale randomized clinical trials are warranted to elucidate whether paeonol are effective in patients with ASCVD.

Paeonol protects against doxorubicin-induced cardiotoxicity by promoting Mfn2-mediated mitochondrial fusion through activating the PKCε-Stat3 pathway

INTRODUCTION

The anti-cancer medication doxorubicin (Dox) is largely restricted in clinical usage due to its significant cardiotoxicity. The only medication approved by the FDA for Dox-induced cardiotoxicity is dexrazoxane, while it may reduce the sensitivity of cancer cells to chemotherapy and is restricted for use. There is an urgent need for the development of safe and effective medicines to alleviate Dox-induced cardiotoxicity.

OBJECTIVES

The objective of this study was to determine whether Paeonol (Pae) has the ability to protect against Dox-induced cardiotoxicity and if so, what are the underlying mechanisms involved.

METHODS

Sprague-Dawley rats and primary cardiomyocytes were used to create Dox-induced cardiotoxicity models. Pae's effects on myocardial damage, mitochondrial function, mitochondrial dynamics and signaling pathways were studied using a range of experimental methods.

RESULTS

Pae enhanced Mfn2-mediated mitochondrial fusion, restored mitochondrial function and cardiac performance both in vivo and in vitro under the Dox conditions. The protective properties of Pae were blunted when Mfn2 was knocked down or knocked out in Dox-induced cardiomyocytes and hearts respectively. Mechanistically, Pae promoted Mfn2-mediated mitochondria fusion by activating the transcription factor Stat3, which bound to the Mfn2 promoter in a direct manner and up-regulated its transcriptional expression. Furthermore, molecular docking, surface plasmon resonance and co-immunoprecipitation studies showed that Pae's direct target was PKCε, which interacted with Stat3 and enabled its phosphorylation and activation. Pae-induced Stat3 phosphorylation and Mfn2-mediated mitochondrial fusion were inhibited when PKCε was knocked down. Furthermore, Pae did not interfere with Dox's antitumor efficacy in several tumor cells.

CONCLUSION

Pae protects the heart against Dox-induced damage by stimulating mitochondrial fusion via the PKCε-Stat3-Mfn2 pathway, indicating that Pae might be a promising therapeutic therapy for Dox-induced cardiotoxicity while maintaining Dox's anticancer activity.

New paeonol derivative C302 reduces hypertension in spontaneously hypertensive rats through endothelium-dependent and endothelium-independent vasodilation

Hypertension is a major risk factor for cardiovascular disease and Chinese herb monomers could provide new structural skeletons for anti-hypertension new drug development. Paeonol is a Chinese herbal monomer extracted from Cortex moutan, exhibited some anti-hypertensive activity. The study focused on the structural optimization of paeonol to provide promising lead compounds for anti-hypertension new drug development. Herein, twelve new paeonol derivatives (PD) were designed and synthesized and their vasodilation activity was evaluated by in vitro vasodilation drug screening platform based on Myograph. Its anti-hypertension activity, PD-C302 (2-hydroxy-4-methoxyvalerophenone) as a representative with the optimal vasodilation activity, was determined by its response to blood pressure in spontaneously hypertensive rats (SHR) in vivo. Moreover, its molecular mechanism was probed by the vasodilation activity of rat superior mesenteric artery rings with or without endothelium pre-contracted by potassium chloride (KCl) or phenylephrine hydrochloride (PE). It was indicated that PD-C302 significantly reduced the blood pressure in SHR, which would involve in PD-C302-induced vasodilation. Furthermore, endothelium-dependent pathways and endothelium-independent pathways both contributed importantly to PD-C302-induced vasodilation at low concentration of PD-C302. Endothelium-independent pathways (vascular smooth muscle cell-mediated vasodilation), were mainly responsible for the PD-C302-induced vasodilation at high concentration of PD-C302, which involved in opening multiple K⁺ channels to restrain Ca²⁺ channels, and then triggered vasodilation to reduce blood pressure. PD-C302 has a simple structure and favorable anti-hypertensive activity in vivo, which could be a promising lead compound for anti-hypertension new drug development.

Paeonol regulates NLRP3 inflammasomes and pyroptosis to alleviate spinal cord injury of rat

Background

Spinal cord injury (SCI) is a life-threatening traumatic disorder. Paeonol has been confirmed to be involved in a variety of diseases. The purpose of this study is to investigate the role of paeonol on SCI progression.

Methods

Sprague Dawley (SD) rat was used for the establishment of SCI model to explore the anti-inflammation, anti-oxidation, and neuroprotective effects of paeonol (60 mg/kg) on SCI in vivo. For in vitro study, mouse primary microglial cells (BV-2) were induced by lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment. The effect of paeonol on the polarization of LPS/ATP-induced BV-2 cells was determined by detection the expression inducible nitric oxide synthase (iNOS), tumour necrosis factor alpha (TNF-α), arginase-1 (Arg-1), and interleukin (IL)-10 using qRT-PCR. ELISA was used to assess the levels of IL-1β, IL-18, TNF-α, malondialdehyde (MDA), and glutathione (GSH). Western blotting was conducted to determine the levels of NLRP3 inflammasomes and TLR4/MyD88/NF-κB (p65) pathway proteins.

Results

Paeonol promoted the recovery of locomotion function and spinal cord structure, and decreased spinal cord water content in rats following SCI. Meanwhile, paeonol reduced the levels of apoptosis-associated speck-like protein (ASC), NLRP3, active caspase 1 and N-gasdermin D (N-GSDMD), repressed the contents of IL-1β, IL-18, TNF-α and MDA, and elevated GSH level. In vitro, paeonol exerted similarly inhibiting effects on pyroptosis and inflammation. Meanwhile, paeonol promoted BV-2 cells M2 polarization. In addition, paeonol also inactivated the expression of TLR4/MyD88/NF-κB (p65) pathway.

Conclusion

Paeonol may regulate NLRP3 inflammasomes and pyroptosis to alleviate SCI, pointing out the potential for treating SCI in clinic.

Osthole alleviates pulmonary vascular remodeling by modulating microRNA-22-3p mediated lipid metabolic reprogramming

BACKGROUND

Pulmonary vascular remodeling is the key pathological feature of pulmonary arterial hypertension (PAH) characterized by a pattern of lipid-related insulin resistance(IR), hormonal derangements and metabolic reprogramming. Our previous studies have demonstrated osthole as natural coumarin compound derived from traditional Chinese medicine is a promising agent for the treatment of pulmonary vascular remodeling in PAH.

PURPOSE

The present study sought to delineate lipid metabolic modulatory mechanism of osthole against pulmonary vascular remodeling by employing an interdisciplinary strategy.

METHODS

Rat model with PAH induced with MCT and PASMCs proliferation model induced with PDGF-BB were established in this study. Serum and lung tissues were used to lipid-related IR, hormone related indexes, pulmonary vascular remodeling analysis. Then, lipid metabolic gene, key enzymes, metabolites and cell proliferation indexes were examined to investigate metabolic regulatory mechanism in vivo and vitro model of PAH.

RESULTS

Osthole significantly showed improvement of lipid-related IR and hormone dysregulation in rats with PAH evidenced by elevating testosterone, androgen receptor and cyclic guanosine monophosphate (cGMP), inhibiting phosphodiesterase-5(PDE-5), modulating lipid-related IR indexes total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), triglyceride (TG)/HDL-C ratio. Additionally, osthole limited key metabolic gene and enzymes to inhibit accumulation of decadienyl-l-carnitine in lipid metabolism, thus to promote oxidative phosphorylation and ATP production through inhibition of miRNA-22-3p, fatty acid translocase (CD36), fatty acid synthase (FAS), phospholipase A2 (PLA2), carnitine palmitoyltransferase 1A (CPT1A), hexokinase 2 (HK2), activation of metabolic switch isocitrate dehydrogenase 3α (IDH3α), NADH dehydrogenase 1 (ND1). We found for the first time miRNA-22-3p modulated PASMCs proliferation and vascular remodeling by regulating lipid metabolism reprogramming. Those modifications uncovered therapeutic mechanism of osthole against pulmonary vascular remodeling.

CONCLUSION

Our findings revealed the function of miRNA-22-3p in PASMCs and demonstrated a novel mechanism that miRNA-22-3p as a regulator can be targeted by osthole to greatly restore dysregulated lipid metabolism thus to alleviate pulmonary vascular remodeling in PAH, which provides novel insight into the potential therapeutic target for PAH, further highlights the development potential of osthole derived new drug against PAH.

Traditional Herbal Medicine Discovery for the Treatment and Prevention of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is characterized by pulmonary artery remodeling that may subsequently culminate in right heart failure and premature death. Although there are currently both non-pharmacological (lung transplantation, etc.) and pharmacological (Sildenafil, Bosentan, and new oral drugs on trial) therapies available, PAH remains a serious and fatal pulmonary disease. As a unique medical treatment, traditional herbal medicine (THM) treatment has gradually exerted its advantages in treating PAH worldwide through a multi-level and multi-target approach. Additionally, the potential mechanisms of THM were deciphered, including suppression of proliferation and apoptosis of pulmonary artery smooth muscle cells, controlling the processes of inflammation and oxidative stress, and regulating vasoconstriction and ion channels. In this review, the effects and mechanisms of the frequently studied compound THM, single herbal preparations, and multiple active components from THM are comprehensively summarized, as well as their related mechanisms on several classical preclinical PAH models. It is worth mentioning that sodium tanshinone IIA sulfonate sodium and tetramethylpyrazine are under clinical trials and are considered the most promoting medicines for PAH treatment. Last, reverse pharmacology, a strategy to discover THM or THM-derived components, has also been proposed here for PAH. This review discusses the current state of THM, their working mechanisms against PAH, and prospects of reverse pharmacology, which are expected to facilitate the natural anti-PAH medicine discovery and development and its bench-to-bedside transformation.

Chronic hypoxia promoted pulmonary arterial smooth muscle cells proliferation through upregulated calcium-sensing receptorcanonical transient receptor potential 1/6 pathway

OBJECTIVES

Although both calcium-sensing receptor (CaSR) and canonical transient receptor potential (TRPC) proteins contribute to chronic hypoxia (CH)-induced pulmonary arterial smooth muscle cells (PASMCs) proliferation, the relationship between CaSR and TRPC in hypoxic PASMCs proliferation remains poorly understood. The goal of this study was to identify that CH promotes PASMCs proliferation through CaSR-TRPC pathway.

METHODS

Rat PASMCs were isolated and treated with CH. Cell proliferation was assessed by cell counting, CCK-8 assay, and EdU incorporation. CaSR and TRPC expressions were determined by qPCR and Western blotting. Store-operated Ca²⁺ entry (SOCE) was assessed by extracellular Ca²⁺ restoration.

RESULTS

In PASMCs, CH enhanced the cell number, cell viability and DNA synthesis, which is accompanied by upregulated expression of CaSR, TRPC1 and TRPC6. Negative CaSR modulators (NPS2143, NPS2390) inhibited, whereas positive modulators (spermine, R568) enhanced, the CH-induced increases in cell number, cell viability and DNA synthesis in PASMCs. Knockdown of CaSR by siRNA inhibited the CH-induced upregulation of TRPC1 and TRPC6 and enhancement of SOCE and attenuated the CH-induced enhancements of cell number, cell viability and DNA synthesis in PASMCs. However, neither siTRPC1 nor siTRPC6 had an effect on the CH-induced CaSR upregulation, although both significantly attenuated the CH-induced enhancements of cell number, cell viability and DNA synthesis in PASMCs.

CONCLUSION

These results demonstrate that upregulated CaSR-TRPC1/6 pathway mediating PASMCs proliferation is an important pathogenic mechanism under hypoxic conditions.

Paeonol Pretreatment Attenuates Anoxia-Reoxygenation Induced Injury in Cardiac Myocytes via a BRCA1 Dependent Pathway

Breast cancer type 1 sensitive protein (BRCA1) is a well-known tumor suppressor and its role in oxidative stress has been confirmed. The purpose of this study is to evaluate whether paeonol has a protective effect on myocardial hypoxia-reoxygenation (A/R) injury, and to explore H9C2 cells through a mechanism-dependent pathway mediated by BRCA1. H9C2 cells were pretreated with paeonol (10 µM) for 18 h before hypoxia was induced to establish a cell model of myocardial ischemia/reperfusion (I/R) injury. Use commercial kits to detect antioxidant indicators, including relative oxygen content (ROS) levels, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), lactate dehydrogenase (LDH) activity, and creatine kinase (CK-MB) and nuclear factor-kappaB (NF-κB) activity. The cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction method. Real-time fluorescent quantitative PCR was used to detect BRCA1 mRNA and protein levels. The expression levels of BRCA1, NLRP3 and ACS were determined by Western blotting. In addition, the release of interleukin (IL)-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) was also evaluated by an enzyme-linked immunosorbent assay (ELISA) kit. The results showed that paeonol (10 µM) can significantly improve the hypoxic A/R damage of H9C2 cells, and the BRCA1 expression of H9C2 cells pretreated with paeonol was significantly increased before A/R damage was induced. BRCA1 is widely known in breast and ovarian cancer. Our data proves that the down-regulation of BRCA1 participates in the decrease of cell viability and the decrease of CK-MB and LDH activities, and protects cells by inhibiting the production of ROS and the activation of Nod-like receptor protein 3 (NLRP3) inflammasomes and NF-κB. In conclusion, paeonol significantly improved the A/R damage of H9C2 cells induced by hypoxia through the BRCA1/ROS-regulated NLRP3 inflammasome/IL-1β and NF-κB/TNF-α/IL-6 pathways. It may be a potential drug against myocardial I/R injury.

Genus Paeonia: A comprehensive review on traditional uses, phytochemistry, pharmacological activities, clinical application, and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Paeonia, which comprises approximately 52 shrubs or herbaceous perennials around the world, is the only genus of the Paeoniaceae and is pervasively distributed in Asia, southern Europe, and North America. Many species of the genus Paeonia have been used for centuries in ethnomedical medical systems.

AIM OF THE REVIEW

The present study aims to summarize the traditional uses, clinical applications, and toxicology of the genus Paeonia, to critically evaluate the state-of-the-art phytochemical and pharmacological studies of this genus published between 2011 and 2020, and to suggest directions for further in-depth research on Paeonia medicinal resources.

MATERIALS AND METHODS

Popular and widely used databases such as PubMed, Scopus, Science Direct, and Google Scholar were searched using the various search strings; from these searches, a number of citations related to the traditional uses, phytochemistry, biological activities, clinical application, and toxicology of the genus Paeonia were retrieved.

RESULTS

The use of 21 species, 2 subspecies, and 7 varieties of the genus Paeonia as traditional herbal remedies has been reported, and many ethnomedicinal uses, such as the treatment of hematemesis, blood stasis, dysmenorrhea, amenorrhea, epilepsy, spasms, and gastritis, have been recorded. The roots and root bark are the most frequently reported parts of the plants used in medicinal applications. In phytochemical investigations, 451 compounds have been isolated from Paeonia plants to date, which contains monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids and steroids, and phenols. Studies of their pharmacological activities have revealed the antioxidant, anti-inflammatory, antitumour, antibacterial, antiviral, cardiovascular protective, and neuroprotective properties of the genus Paeonia. In particular, some bioactive extracts and compounds (total glucosides of peony (TGP), paeonol, and paeoniflorin) have been used as therapeutic drugs or tested in clinical trials. In addition to the "incompatibility" of the combined use of "shaoyao" and Veratrum nigrum L. roots in traditional Chinese medicine theory, Paeonia was considered to have no obvious toxicity based on the available toxicological tests.

CONCLUSION

A large number of phytochemical and pharmacological reports have indicated that Paeonia is an important medicinal herb resource, and some of its traditional uses including the treatment of inflammation and cardiovascular diseases and its use as a neuroprotective agent, have been partially confirmed through modern pharmacological studies. Monoterpenoid glucosides are the main active constituents. Although many compounds have been isolated from Paeonia plants, the biological activities of only a few of these compounds (paeoniflorin, paeonol, and TGP) have been extensively investigated. Some paeoniflorin structural analogues and resveratrol oligomers have been preliminarily studied. With the exception of several species (P. suffruticosa, P. ostii, P. lactiflora, and P. emodi) that are commonly used in folk medicine, many medicinal species within the genus do not receive adequate attention. Conducting phytochemical and pharmacological experiments on these species can provide new clues that may lead to the discovery of medicinal resources. It is necessary to identify the effective phytoconstituents of crude extracts of Paeonia that displayed pharmacological activities by bioactivity-guided isolation. In addition, comprehensive plant quality control, and toxicology and pharmacokinetic studies are needed in the future studies.

A novel organic cation transporter involved in paeonol transport across the inner blood-retinal barrier and changes in uptake in high glucose conditions

Paeonol exerts various pharmacological effects owing to its antiangiogenic, antioxidant, and antidiabetic activities. We aimed to investigate the transport mechanism of paeonol across the inner blood-retinal barrier both in vitro and in vivo. The carotid artery single injection method was used to investigate the retina uptake index of paeonol. The retina uptake index (RUI) value of [³H]paeonol was dependent on both concentration and pH. This value decreased significantly in the presence of imperatorin, tramadol, and pyrilamine when compared to the control. However, para-aminohippuric acid, choline, and taurine had no effect on the RUI value. Conditionally immortalized rat retina capillary endothelial cells (TR-iBRB cell lines) were used as an in vitro model of the inner blood-retinal barrier (iBRB). The uptake of [³H]paeonol by the TR-iBRB cell lines was found to be time-, concentration-, and pH-dependent. However, the uptake was unaffected by the absence of sodium or by membrane potential disruption. Moreover, in vitro structural analog studies revealed that [³H]paeonol uptake was inhibited in the presence of organic cationic compounds including imperatorin, clonidine and tramadol. This is consistent with the results obtained in vivo. In addition, transfections with OCTN1, 2 or plasma membrane monoamine transporter (PMAT) small interfering RNA did not affect paeonol uptake in TR-iBRB cell lines. Upon pre-incubation of these cell lines with high glucose (HG) media, [³H]paeonol uptake decreased and mRNA expression levels of angiogenetic factors, such as hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) increased. However, after the pretreatment of unlabeled paeonol in HG conditions, the mRNA levels of VEGF and HIF-1 were comparatively reduced, and the [³H]paeonol uptake rate was restored. After being exposed to inflammatory conditions induced by glutamate, TNF-α, and LPS, paeonol and propranolol pretreatment significantly increased the uptake of both [³H]paeonol and [³H]propranolol in TR-iBRB cell lines compared to their respective controls. Our results demonstrate that the transport of paeonol to the retina across the iBRB may involve the proton-coupled organic cation antiporter system, and the uptake of paeonol is changed by HG conditions.

MicroRNA-874-5p regulates autophagy and proliferation in pulmonary artery smooth muscle cells by targeting Sirtuin 3

Autophagy is a major cause of pathological vascular remodeling under hypoxic pulmonary hypertension (PH). Sirtuin 3 (Sirt 3) has recently been reported to be involved in the regulation of autophagy, however, its role as an autophagy regulator during hypoxic PH, particularly the molecular mechanism, remains poorly understood. In the present study, Western blot, immunohistochemistry, immunofluorescence, bromodeoxyuridine incorporation and cell cycle analyses were performed to elucidate the underlying mechanism of hypoxia-induced autophagy and cell proliferation with respect to Sirt 3. We observed that the Sirt 3 expression was decreased under hypoxia and that Sirt 3 overexpression significantly inhibited the effects of hypoxia on autophagy. Next, we investigated the mechanistic role of microRNAs in Sirt 3-associated autophagy under hypoxic conditions, with luciferase reporter, microscale thermophoresis and RNA immunoprecipitation assays, results confirming that Sirt 3 is a direct target of miR-874-5p. Furthermore, miR-874-5p was upregulated following hypoxia, and miR-874-5p depletion in turn inhibited autophagy and consequently suppressed abnormal smooth muscle cell proliferation. These findings provide insight into the contribution of the miR-874-5p/Sirt 3 cascade with regard to changes in autophagy and proliferation associated with PH.

Paeonol protects mitochondrial injury and prevents pulmonary vascular remodeling in hypoxia

Mitochondrial injury of pulmonary artery smooth muscle cells (PASMCs) is an important stage in the development of pulmonary arterial hypertension (PAH). Recent studies revealed that Paeonol exerts anti-proliferative effects on vascular smooth muscle cells. However, whether Paeonol is directly involved in mitochondrial injury related to PAH remains unknown. Here, we found that hypoxia-induced mitochondrial injury in vivo was alleviated in the presence of Paeonol. Hypoxia mediated the mitochondrial injuries in PASMCs in vitro, including decreased ATP generation, morphological alterations, mitochondrial polarization and increased reactive oxygen species production, which were suppressed by Paeonol. Our results also indicated that the expression of peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) was regulated by Paeonol. Paeonol caused significant alterations in mitochondrion-dependent apoptosis through PGC-1α in PASMCs. Taken together, these results provide the first evidence confirming the protective effect of Paeonol in mediating mitochondrial injury under hypoxia and elucidating the necessary role of PGC-1α in the effects of Paeonol in inducing PASMC apoptosis.

Stox1 induced the proliferation and cell cycle arrest in pulmonary artery smooth muscle cells via AKT signaling pathway

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by the vascular remodeling that also involves proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). Overexpression of Storkhead box (STOX1) regulates genes involved hypoxia, redox balance, nitric oxide, and energy metabolism. In this study, we supposed Stox1 adjusted cells proliferation and migration in PASMCs development and played an important role in the pulmonary arterial vascular remodeling.

METHODS

Hemodynamic assay and Right ventricular morphometric assay were used to check the rat model of PAH. HE staining was used to examine the arterial wall thickness. Masson staining showed that the deposition of collagen was significantly increased in PAH. In addition, Stox1 were assessed by immunofluorescence and immunohistochemistry staining. The effect of Stox1 on PASMCs was assessed by cell counting Kit-8 assay (CCK-8 assay), Scratch-Wound assay, EdU staining assay, Cell cycle analysis and Western blot.

RESULTS

Right ventricular systolic pressure (RVSP) and right ventricular were significantly increased in hypoxia group and monocrotaline group compared to control group. The expression of Stox1 was increased in lung tissues in PAH rats. In vitro, the expression of Stox1 was up-regulated with time-dependent manner in hypoxia condition. Meanwhile, Stxo1 promoted the proliferation and migration in hypoxia-treated PASMCs. Moreover, we found that hypoxia promoted the expression of PCNA, Cyclin E and Cyclin A, increased more cells from G₀/G₁ phase to S phase and induced the activation of AKT proteins, which was significantly attenuated by inhibition of Stox1 expression in PASMCs.

CONCLUSION

These findings indicated that Stox1 induced proliferation of PASMCs and the effect is, at least in part, mediated through AKT signaling pathway.

Paeonol: pharmacological effects and mechanisms of action

Paeonia suffruticosa possesses various medicinal benefits and has been used extensively in traditional oriental medicine for thousands of years. Paeonol is the main component isolated from the root bark of Paeonia suffruticosa. The pharmacological effects of Paeonia suffruticosa are mostly attributed to paeonol. Paeonol injection has been successfully applied in China for nearly 50 years for inflammation/pain-related indications. Currently, the dosage forms of paeonol approved by China Food and Drug Administration include tablet, injection, and external preparations such as ointment and adhesive plaster. So far, the clinical applications of paeonol are mainly focusing on the anti-inflammatory activity. Studies of other pharmacological activities of paeonol are developing rapidly, and which may play an important role in the future. Besides, substantial mechanisms of pharmacological action of paeonol have been clarified in recent years. In this review, we summarize the pharmacological effects anti-inflammatory, neuroprotective, anti-tumor, anti-cardiovascular diseases and associated mechanisms of action of paeonol up to date.