Rutaecarpine prevented ox-LDL-induced VSMCs dysfunction through inhibiting overexpression of connexin 43

Major Indole Alkaloids in Evodia Rutaecarpa: The Latest Insights and Review of Their Impact on Gastrointestinal Diseases

Evodia rutaecarpa, the near-ripe fruit of Euodia rutaecarpa (Juss.) Benth, Euodia rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang, or Euodia rutaecarpa (Juss.) Benth. var. bodinieri (Dode) Huang, is a famous herbal medicine with several biological activities and therapeutic values, which has been applied for abdominalgia, abdominal distension, vomiting, and diarrhea as a complementary and alternative therapy in clinic. Indole alkaloids, particularly evodiamine (EVO), rutaecarpine (RUT), and dedhydroevodiamine (DHE), are received rising attention as the major bioactivity compounds in Evodia rutaecarpa. Therefore, this review summarizes the physicochemical properties, pharmacological activities, pharmacokinetics, and therapeutic effects on gastrointestinal diseases of these three indole alkaloids with original literature collected by PubMed, Web of Science Core Collection, and CNKI up to June 2023. Despite sharing the same parent nucleus, EVO, RUT, and DHE have different structural and chemical properties, which result in different advantages of biological effects. In their wide range of pharmacological activities, the anti-migratory activity of RUT is less effective than that of EVO, and the neuroprotection of DHE is significant. Additionally, although DHE has a higher bioavailability, EVO and RUT display better permeabilities within blood-brain barrier. These three indole alkaloids can alleviate gastrointestinal inflammatory in particular, and EVO also has outstanding anti-cancer effect, although clinical trials are still required to further support their therapeutic potential.

Downregulation of connexin 43-based gap junctions underlies propofol-induced excessive relaxation in hypertensive vascular smooth muscle cells

BACKGROUND

Postinduction hypotension caused by propofol remains a non-negligible problem for anesthesiologists, and is especially severe in chronic hypertensive patients with long-term vasoconstriction and decreased vascular elasticity. The functional change in gap junctions composed of Cx43 (Cx43-GJs) is reported as the biological basis of synchronized contraction or relaxation of blood vessels. Thus, we investigated the role of Cx43-GJs in propofol-induced dramatic blood pressure fluctuations in chronic hypertensive patients, and their internal mechanisms.

METHODS

Human umbilical artery smooth muscle cells (HUASMCs) were pretreated with long-term angiotensin II (Ang II), with or without propofol, to simulate the contraction and relaxation of normal and hypertensive VSMCs during anesthesia induction. The levels of F-actin polymerization and MLC2 phosphorylation were used as indicators to observe the contraction and relaxation of HUASMCs. Different specific activators, inhibitors and siRNAs were used to explore the role of Cx43-GJs and Ca²⁺ as well as the RhoA/ LIMK2/cofilin and RhoA/MLCK signaling pathways in the contraction and relaxation of normal and hypertensive HUASMCs.

RESULTS

Both F-actin polymerization and MLC2 phosphorylation were significantly enhanced in Ang II-pretreated HUASMCs, along with higher expression of Cx43 protein and stronger function of Cx43-GJs than in normal HUASMCs. However, with propofol administration, similar to Gap26 and Cx43-siRNA, the function of Cx43-GJs in Ang II-pretreated HUASMCs was inhibited compared with that in normal HUASMCs, accompanied by a larger decrease in intracellular Ca²⁺ and the RhoA/LIMK2/cofilin and RhoA/MLCK signaling pathways. Eventually F-actin polymerization and MLC2 phosphorylation were more dramatically decreased. However, these effects could be reversed by RA with enhanced Cx43-GJ function.

CONCLUSION

Long-term exposure to Ang II significantly enhanced the expression of the Cx43 protein and function of Cx43-GJs in HUASMCs, resulting in the accumulation of intracellular Ca²⁺ and the activation of its downstream RhoA/LIMK2/cofilin and RhoA/MLCK signaling pathways, which maintained HUASMCs in a state of excessive-contraction. With inhibition of Cx43-GJs by propofol in Ang II-pretreated HUASMCs, intracellular Ca²⁺ and its downstream signaling pathways were dramatically inhibited, which ultimately excessively relaxed HUASMCs. This is the reason why the blood pressure fluctuation of patients with chronic hypertension was more severe after receiving propofol induction. Video Abstract.

Traditional Chinese medicine Euodiae Fructus: botany, traditional use, phytochemistry, pharmacology, toxicity and quality control

Euodiae Fructus, referred to as "Wuzhuyu" in Chinese, has been used as local and traditional herbal medicines in many regions, especially in China, Japan and Korea, for the treatment of gastrointestinal disorders, headache, emesis, aphtha, dermatophytosis, dysentery, etc. Substantial investigations into their chemical and pharmacological properties have been performed. Recently, interest in this plant has been focused on the different structural types of alkaloids like evodiamine, rutaecarpine, dehydroevodiamine and 1-methyl-2-undecyl-4(1H)-quinolone, which exhibit a wide range of pharmacological activities in preclinical models, such as anticancer, antibacterial, anti-inflammatory, anti-cardiovascular disease, etc. This review summarizes the up-to-date and comprehensive information concerning the botany, traditional uses, phytochemistry, pharmacology of Euodiae Fructus together with the toxicology and quality control, and discusses the possible direction and scope for future research on this plant.

The Potential Role of Connexins in the Pathogenesis of Atherosclerosis

Connexins (Cx) are members of a protein family which enable extracellular and intercellular communication through hemichannels and gap junctions (GJ), respectively. Cx take part in transporting important cell-cell messengers such as 3',5'-cyclic adenosine monophosphate (cAMP), adenosine triphosphate (ATP), and inositol 1,4,5-trisphosphate (IP3), among others. Therefore, they play a significant role in regulating cell homeostasis, proliferation, and differentiation. Alterations in Cx distribution, degradation, and post-translational modifications have been correlated with cancers, as well as cardiovascular and neurological diseases. Depending on the isoform, Cx have been shown either to promote or suppress the development of atherosclerosis, a progressive inflammatory disease affecting large and medium-sized arteries. Cx might contribute to the progression of the disease by enhancing endothelial dysfunction, monocyte recruitment, vascular smooth muscle cell (VSMC) activation, or by inhibiting VSMC autophagy. Inhibition or modulation of the expression of specific isoforms could suppress atherosclerotic plaque formation and diminish pro-inflammatory conditions. A better understanding of the complexity of atherosclerosis pathophysiology linked with Cx could result in developing novel therapeutic strategies. This review aims to present the role of Cx in the pathogenesis of atherosclerosis and discusses whether they can become novel therapeutic targets.

Inhibition of Connexin 43 reverses ox-LDL-mediated inhibition of autophagy in VSMC by inhibiting the PI3K/Akt/mTOR signaling pathway

Background

Oxidized low-density lipoproteins (ox-LDL) may induce foam cell formation from the vascular smooth muscle cell (VSMC) by inhibiting VSMC autophagy. This process accelerates the formation of atherosclerosis (AS). Connexin 43 (Cx43), which is the most widely distributed connexin in VSMC is associated with autophagy. However, the mechanism of action and the involvement of Cx43 in ox-LDL-inhibited VSMC autophagy remain unclear.

Methods

The primary VSMC were obtained and identified, before primary VSMC were pretreated with an inhibitor (Cx43-specific inhibitor Gap26 and PI3K inhibitor LY294002) and stimulated with ox-LDL.

Results

Ox-LDL not only inhibited autophagy in VSMC via downregulation of autophagy-related proteins (such as Beclin 1, LC3B, p62), but also increased Cx43 protein levels. Then we added Gap26 to VSMC in the ox-LDL+Gap26 group, in which autophagy-related proteins were increased and the accumulation of lipid droplets was reduced. These result suggested that an enhanced level of autophagy and an alleviation of lipid accumulation might be caused by inhibiting Cx43 in VSMC. The phosphorylation levels of PI3K, AKT, mTOR were increased by ox-LDL, thus down-regulating autophagy-related proteins. However, this situation was partially reversed by the Gap26. Moreover, Cx43 expression were decreased by LY294002 in ox-LDL-induced VSMCs.

Conclusion

Inhibiting Cx43 may activate VSMC autophagy to inhibit foam cell formation by inhibiting the PI3K/AKT/mTOR signaling pathway.

Biology of quinoline and quinazoline alkaloids

Quinoline and quinazoline alkaloids, two important classes of N-based heterocyclic compounds, have attracted scientific and popular interest worldwide since the 19th century. More than 600 compounds have been isolated from nature to date. To build on our two prior reviews, we reexamined the promising molecules described in previous reports and provided updated literature on novel quinoline and quinazoline alkaloids isolated over the past 5 years. This chapter reviews and discusses 205 molecules with a broad range of bioactivities, including antiparasitic and insecticidal, antibacterial and antifungal, cardioprotective, antiviral, anti-inflammatory, and other effects. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.

Circ_0010283/miR-377-3p/Cyclin D1 Axis Is Associated With Proliferation, Apoptosis, Migration, and Inflammation of Oxidized Low-density Lipoprotein-Stimulated Vascular Smooth Muscle Cells

ABSTRACT

Circular RNAs have been reported as vital regulators and promising therapeutic targets in multiple human diseases, including atherosclerosis (AS). However, the functional roles of circ_0010283 in AS remain unclear. The real-time quantitative polymerase chain reaction was used to determine the expression levels of circ_0010283, microRNA (miR)-377-3p, and cyclin D1 (CCND1) in serum samples. The vascular smooth muscle cells (VSMCs) were treated with oxidized low-density lipoprotein (ox-LDL) to establish the in vitro cell model of AS. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide and clonal colony-forming assays were performed to assess cell proliferation. The apoptosis was determined by flow cytometry assay. The migration of VSMCs was examined by wound healing and transwell assays. Western blot analysis was used to quantify protein expression. The association among circ_0010283, miR-377-3p, and CCND1 was confirmed by dual-luciferase reporter assay. We found that the serum level of circ_0010283 was upregulated in patients with AS and treatment with ox-LDL also increased the expression of circ_0010283 in VSMCs. Treatment with ox-LDL also increased proliferation, migration, and inflammation while inhibited apoptosis in VSMCs, which was overturned by silencing of circ_0010283. Moreover, miR-377-3p was a target of circ_0010283, and downregulation of miR-377-3p counteracted circ_0010283 silencing-induced effects on ox-LDL-stimulated VSMCs. The overexpression of miR-377-3p inhibited proliferation, migration, and inflammation while induced apoptosis of VSMCs by targeting CCND1. CCND1 was a target of miR-377-3p, and circ_0010283 acted as the miR-377-3p sponge to increase CCND1 expression. Circ_0010283 regulated proliferation, apoptosis, migration, and inflammation of ox-LDL-stimulated VSMCs through modulating miR-377-3p and CCND1.

Lysophosphatidylcholine induces apoptosis and inflammatory damage in brain microvascular endothelial cells via GPR4-mediated NLRP3 inflammasome activation

Lysophosphatidylcholine (LPC), as the main active component of oxidized low-density lipoproteins (ox-LDLs), has significant effects in cerebrovascular disease. However, the complex mechanism by which LPC functions in brain microvascular endothelial cells (BMECs) is not clearly understood. In this study, BMECs were transfected with G protein-coupled receptor 4 (GPR4) siRNA or an NLRP3-overexpression plasmid, and GPR4 expression was identified by RT-qPCR and western blotting; IL-1β, IL-18, and IL-33 levels were evaluated by ELISA. Apoptosis was monitored by flow cytometry and Hoechst staining, while Caspase 3, ASC, NLRP3, and GPR4 protein expression were examined by western blotting. Our results showed that LPC significantly increased the levels of inflammatory cytokines (IL-1β, IL-18, and IL-33) and markedly induced apoptosis and NLRP3 inflammasome activation in BMECs. Moreover, LPC notably upregulated GPR4 in BMECs, and knockdown of GPR4 significantly attenuated the effects of LPC in BMECs. Above all, we also proved that LPC induced apoptosis and inflammatory injury in BMECs by causing GPR4 to activate NLRP3 inflammasomes. Therefore, GPR4-mediated activation of NLRP3 inflammasomes might be the underlying mechanism by which LPC promotes the progression of cerebrovascular disease. In summary we found that LPC is an important pathogenic factor in cerebrovascular disease, and can induce GPR4 to active NLRP3 inflammasomes.

CircMTO1 inhibits ox-LDL-stimulated vascular smooth muscle cell proliferation and migration via regulating the miR-182-5p/RASA1 axis

Background

Circular RNAs (circRNAs) play critical roles in the development of atherosclerosis (AS). This study investigated the role of circMTO1 in the progression of AS.

Methods

Serum samples from AS patients and healthy volunteers and vascular smooth muscle cells (VSMCs) were used as the study materials. The expressions of circMTO1 and miR-182-5p were measured by RT-qPCR. The effects of circMTO1, miR-182-5p, and RASA1 on VSMC proliferation and apoptosis were examined by MTT and BrdU assays and wound healing and flow cytometric analyses, respectively. Downstream target genes of circMTO1 and miR-182-5p were predicted using target gene prediction and screening and confirmed using a luciferase reporter assay. RASA1 expression was detected by RT-qPCR and Western blot.

Results

circMTO1 expression was decreased, while miR-182-5p expression was increased in human AS sera and oxidized low-density lipoprotein (ox-LDL)-stimulated VSMCs. CircMTO1 overexpression inhibited the proliferation and promoted the apoptosis of ox-LDL-stimulated VSMCs. CircMTO1 was found to be served as a sponge of miR-182-5p and RASA1 as a target of miR-182-5p. Moreover, circMTO1 acted as a ceRNA of miR-182-5p to enhance RASA1 expression. Furthermore, miR-182-5p overexpression and RASA1 knockdown reversed the effects of circMTO1 overexpression on the proliferation, migration, and apoptosis of ox-LDL-stimulated VSMCs.

Conclusion

CircMTO1 inhibited the proliferation and promoted the apoptosis of ox-LDL-stimulated VSMCs by regulating miR-182-5p/RASA1 axis. These results suggest that circMTO1 has potential in AS treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00330-2.

miR-33a-5p Suppresses ox-LDL-Stimulated Calcification of Vascular Smooth Muscle Cells by Targeting METTL3

Oxidized low-density lipoprotein (ox-LDL) accumulation in the vascular wall plays a pivotal role in the development of atherosclerosis and vascular calcification. However, few studies focus on the regulatory roles of microRNAs in ox-LDL stimulated vascular calcification. The aim of the present study was to investigate how miR-33a-5p regulated vascular calcification stimulated by ox-LDL. In the present study, miR-33a-5p was downregulated during vascular smooth muscle cells (VSMCs) calcification and upon ox-LDL treatment. ox-LDL significantly stimulated VSMCs calcification, while miR-33a-5p overexpression by its mimics transfection inhibited alkaline phosphatase (ALP) activity, mineralization and marker genes associated with VSMCs calcification even in the presence of ox-LDL. Methyltransferase like 3 (METTL3) was the target gene of miR-33a-5p. METTL3 was upregulated during VSMCs calcification and upon ox-LDL treatment. When VSMCs were transfected with miR-33a-5p mimics, METTL3 was downregulated. METTL3 downregulation by siRNA method decreased VSMCs calcification even in the presence of ox-LDL. Taken together, these results suggest miR-33a-5p suppresses VSMCs calcification stimulated by ox-LDL via targeting METTL3, highlighting the critical role of miR-33a-5p/METTL3 in vascular calcification.

Analyzing the shear-induced sensitization of mechanosensitive ion channel Piezo-1 in human aortic endothelial cells

Mechanosensitive ion channels mediate endothelial responses to blood flow and orchestrate their physiological function in response to hemodynamic forces. In this study, we utilized microfluidic technologies to study the shear-induced sensitization of endothelial Piezo-1 to its selective agonist, Yoda-1. We demonstrated that shear stress-induced sensitization is brief and can be impaired when exposing aortic endothelial cells to low and proatherogenic levels of shear stress. Our results suggest that shear stress-induced sensitization of Piezo-1 to Yoda-1 is independent of cell-cell adhesion and is mediated by the PI3K-AKT signaling pathway. We also found that shear stress increases the membrane density of Piezo-1 channels in endothelial cells. To further confirm our findings, we performed experiments using a carotid artery ligation mouse model and demonstrated that transient changes in blood-flow pattern, resulting from a high-degree ligation of the mouse carotid artery alters the distribution of Piezo-1 channels across the endothelial layer. These results suggest that shear stress influences the function of Piezo-1 channels via changes in membrane density, providing a new model of shear-stress sensitivity for Piezo-1 ion channel.

Angiotensin II induces RAW264.7 macrophage polarization to the M1‑type through the connexin 43/NF‑κB pathway

Angiotensin II (AngII) serves an important inflammatory role in cardiovascular disease; it can induce macrophages to differentiate into the M1-type, produce inflammatory cytokines and resist pathogen invasion, and can cause a certain degree of damage to the body. Previous studies have reported that connexin 43 (Cx43) and NF-κB (p65) are involved in the AngII-induced inflammatory pathways of macrophages; however, the mechanisms underlying the effects of Cx43 and NF-κB (p65) on AngII-induced macrophage polarization have not been determined. Thus, the present study aimed to investigate the effects of Cx43 and NF-κB (p65) on the polarization process of AngII-induced macrophages. The macrophage polarization-related proteins and mRNAs were examined by flow cytometry, western blotting, immunofluorescence, ELISA and reverse transcription-quantitative PCR analyses. RAW264.7 macrophages were treated with AngII to simulate chronic inflammation and it was subsequently found that AngII promoted RAW 264.7 macrophage polarization towards the M1-type by such effects as the release of inducible nitric oxide synthase (iNOS), tumour necrosis factor (TNF)-α, IL-1β, the secretion of IL-6, and the expression of M1-type indicators, such as CD86. Simultaneously, compared with the control group, the protein expression levels of Cx43 and phosphorylated (p)-p65 were significantly increased following AngII treatment. The M1-related phenotypic indicators, iNOS, TNF-α, IL-1β, IL-6 and CD86, were inhibited by the NF-κB (p65) signalling pathway inhibitor BAY117082. Similarly, the Cx43 inhibitors, Gap26 and Gap19, also inhibited the expression of M1-related factors, and the protein expression levels of p-p65 in the Gap26/Gap19 groups were significantly decreased compared with the AngII group. Altogether, these findings suggested that AngII may induce the polarization of RAW264.7 macrophages to the M1-type through the Cx43/NF-κB (p65) signalling pathway.

Rutaecarpine may improve neuronal injury, inhibits apoptosis, inflammation and oxidative stress by regulating the expression of ERK1/2 and Nrf2/HO-1 pathway in rats with cerebral ischemia-reperfusion injury

BACKGROUND

Cerebral ischemia-reperfusion (CI/R) injury is a more serious brain injury caused by the recovery of blood supply after cerebral ischemia for a certain period of time. Rutaecarpine (Rut) is an alkaloid isolated from Evodia officinalis with various biological activities. Previous studies have shown that Rut has a certain protective effect on ischemic brain injury, but the specific molecular mechanism is still unknown.

METHODS

In this study, a rat model of CI/R was established to explore the effects and potential molecular mechanisms of Rut on CI/R injury in rats.

RESULTS

The results showed that Rut alleviated neuronal injury induced by CI/R in a dose-dependent manner. Besides, Rut inhibited neuronal apoptosis by inhibiting the activation of caspase 3 and the expression of Bax. In addition, Rut alleviated the inflammatory response and oxidative stress caused by CI/R through inhibiting the production of pro-inflammatory factors (IL-6 and IL-1β), lactate dehydrogenase (LDH), malondialdehyde (MDA) and ROS, and increased the levels of anti-inflammatory factors (IL-4 and IL-10) and superoxide dismutase (SOD). Biochemically, Western blot analyses showed that Rut inhibited the phosphorylation of ERK1/2 and promoted the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) pathway-related proteins (Nrf2, heme oxygenase 1 (HO-1) and NAD (P) H-quinone oxidoreductase 1) in a dose-dependent manner. These results show that Rut may alleviate brain injury induced by CI/R by regulating the expression of ERK1/2 and the activation of Nrf2/HO-1 pathway.

CONCLUSION

In conclusion, these results suggest that Rut may be used as an effective therapeutic agent for damage caused by CI/R.