Cav-1 promotes atherosclerosis by activating JNK-associated signaling

Puerarin inhibits HDAC1-induced oxidative stress disorder by activating JNK pathway and alleviates acrolein-induced atherosclerosis

OBJECTIVE

Atherosclerosis (AS) is a common pathogenesis of cardiovascular diseases. Puerarin (Pue) is a Chinese herbal remedy used to prevent and treat AS. Here, this research investigated the effect of Pue on AS progression.

METHODS

ApoE-/- mice were induced with acrolein. Body weight, blood lipid index, inflammatory factors, mitochondrial oxidative stress, and lipid deposition were detected. IL-6 and TNF-α were detected by ELISA. Oil red staining and H&E staining were used to observe the aortic sinus plaque lesions. Serum expressions of inflammatory factors IL-6, TNF-a, SOD, GSH and MDA were detected by ELISA, the mRNA expression levels of HDAC1 in the aorta were detected by RT-qPCR, and IL-6 and TNF-α in the aorta were detected by immunohistochemistry. JNK, p-JNK, OPA-1, and HDAC1 were detected by Western blotting.

RESULTS

Pue administration can effectively reduce lipid accumulation in AS mice induced by acrolein. Pue promoted the activity of SOD, GSH and MDA, and inhibited the formation of atherosclerotic plaques and the process of aortic histological changes. Pue reduced IL-6 and TNF-α. HDAC1 expression was down-regulated and p-JNK-1 and JNK protein expression was up-regulated.

CONCLUSION

Pue reduces inflammation and alleviates AS induced by acrolein by mediating the JNK pathway to inhibit HDAC1-mediated oxidative stress disorder.

Caveolae and caveolin-1 as targets of dietary polyphenols for protection against vascular endothelial dysfunction

Caveolae, consisting of caveolin-1 proteins, are ubiquitously present in endothelial cells and contribute to normal cardiovascular functions by acting as a platform for cellular signaling pathways as well as transcytosis and endocytosis. However, caveolin-1 is thought to have a proatherogenic role by inhibiting endothelial nitric oxide synthase activity and Nrf2 activation, or by promoting inflammation through NF-κB activation. Dietary polyphenols were suggested to exert anti-atherosclerotic effects by a mechanism involving the inhibition of endothelial dysfunction, by which they can regulate redox-sensitive signaling pathways in relation to NF-κB and Nrf2 activation. Some monomeric polyphenols and microbiota-derived catabolites from monomeric polyphenols or polymeric tannins might be responsible for the inhibition, because they can be transferred into the circulation from the digestive tract. Several polyphenols were reported to modulate caveolin-1 expression or its localization in caveolae. Therefore, we hypothesized that circulating polyphenols affect caveolae functions by altering its structure leading to the release of caveolin-1 from caveolae, and attenuating redox-sensitive signaling pathway-dependent caveolin-1 overexpression. Further studies using circulating polyphenols at a physiologically relevant level are necessary to clarify the mechanism of action of dietary polyphenols targeting caveolae and caveolin-1.

JNK regulates ciliogenesis through the interflagellar transport complex and actin networks

The c-Jun N-terminal kinase (JNK) regulates various important physiological processes. Although the JNK pathway has been under intense investigation for over 20 yr, its complexity is still perplexing, with multiple protein partners underlying the diversity of its activity. We show that JNK is associated with the basal bodies in both primary and motile cilia. Loss of JNK disrupts basal body migration and docking and leads to severe ciliogenesis defects. JNK's involvement in ciliogenesis stems from a dual role in the regulation of the actin networks of multiciliated cells (MCCs) and the establishment of the intraflagellar transport-B core complex. JNK signaling is also critical for the maintenance of the actin networks and ciliary function in mature MCCs. JNK is implicated in the development of diabetes, neurodegeneration, and liver disease, all of which have been linked to ciliary dysfunction. Our work uncovers a novel role of JNK in ciliogenesis and ciliary function that could have important implications for JNK's role in the disease.

Caveolin-1 in endothelial cells: A potential therapeutic target for atherosclerosis

Atherosclerosis (AS) is a chronic vascular disease characterized by lipid accumulation and the activation of the inflammatory response; it remains the leading nation-wide cause of death. Early in the progression of AS, stimulation by pro-inflammatory agonists (TNF-α, LPS, and others), oxidized lipoproteins (ox-LDL), and biomechanical stimuli (low shear stress) lead to endothelial cell activation and dysfunction. Consequently, it is crucial to investigate how endothelial cells respond to different stressors and ways to alter endothelial cell activation in AS development, as they are the earliest cells to respond. Caveolin-1 (Cav1) is a 21-24-kDa membrane protein located in caveolae and highly expressed in endothelial cells, which plays a vital role in regulating lipid transport, inflammatory responses, and various cellular signaling pathways and has atherogenic effects. This review summarizes recent studies on the structure and physiological functions of Cav1 and outlines the potential mechanisms it mediates in AS development. Included are the roles of Cav1 in the regulation of endothelial cell autophagy, response to shear stress, modulation of the eNOS/NO axis, and transduction of inflammatory signaling pathways. This review provides a rationale for proposing Cav1 as a novel target for the prevention of AS, as well as new ideas for therapeutic strategies for early AS.

Deciphering the relationship between caveolae-mediated intracellular transport and signalling events

The caveolae-mediated transport across polarized epithelial cell barriers has been largely deciphered in the last decades and is considered the second essential intracellular transfer mechanism, after the clathrin-dependent endocytosis. The basic cell biology knowledge was supplemented recently, with the molecular mechanisms beyond caveolae generation implying the key contribution of the lipid-binding proteins (the structural protein Caveolin and the adapter protein Cavin), along with the bulb coat stabilizing molecules PACSIN-2 and Eps15 homology domain protein-2. The current attention is focused also on caveolae architecture (such as the bulb coat, the neck, the membrane funnel inside the bulb, and the associated receptors), and their specific tasks during the intracellular transport of various cargoes. Here, we resume the present understanding of the assembly, detachment, and internalization of caveolae from the plasma membrane lipid raft domains, and give an updated view on transcytosis and endocytosis, the two itineraries of cargoes transport via caveolae. The review adds novel data on the signalling molecules regulating caveolae intracellular routes and on the transport dysregulation in diseases. The therapeutic possibilities offered by exploitation of Caveolin-1 expression and caveolae trafficking, and the urgent issues to be uncovered conclude the review.

5,2′-Dibromo-2,4′,5′-trihydroxydiphenylmethanone Inhibits LPS-Induced Vascular Inflammation by Targeting the Cav1 Protein

Vascular inflammation is directly responsible for atherosclerosis. 5,2′-Dibromo-2,4′,5′-trihydroxydiphenylmethanone (TDD), a synthetic bromophenol derivative, exhibits anti-atherosclerosis and anti-inflammatory effects. However, the underlying pathways are not yet clear. In this study, we first examined the effects of TDD on toll-like receptor-4 (TLR4) activity, the signaling receptor for lipopolysaccharide (LPS), and found that TDD does not inhibit LPS-induced TLR4 expression in EA.hy926 cells and the vascular wall in vivo. Next, we investigated the global protein alterations and the mechanisms underlying the action of TDD in LPS-treated EA.hy926 cells using an isobaric tag for the relative and absolute quantification technique. Western blot analysis revealed that TDD inhibited NF-κB activation by regulating the phosphorylation and subsequent degradation IκBα. Among the differentially expressed proteins, TDD concentration-dependently inhibited Caveolin 1(Cav1) expression. The interaction between Cav1 and TDD was determined by using biolayer interference assay, UV-vis absorption spectra, fluorescence spectrum, and molecular docking. We found that TDD can directly bind to Cav1 through hydrogen bonds and van der Waals forces. In conclusion, our results showed that TDD inhibited LPS-induced vascular inflammation and the NF-κB signaling pathway by specifically targeting the Cav1 protein. TDD may be a novel anti-inflammatory compound, especially for the treatment of atherosclerosis.

More than Just a Monolayer: the Multifaceted Role of Endothelial Cells in the Pathophysiology of Atherosclerosis

Purpose of the Review

In this review, we summarize current insights into the versatile roles of endothelial cells in atherogenesis.

Recent Findings

The vascular endothelium represents the first barrier that prevents the entry of lipoproteins and leukocytes into the vessel wall, thereby controlling two key events in the pathogenesis of atherosclerosis. Disturbance of endothelial homeostasis increases vascular permeability, inflammation, and cellular trans-differentiation, which not only promotes the build-up of atherosclerotic plaques but is also involved in life-threatening thromboembolic complications such as plaque rupture and erosion. In this review, we focus on recent findings on endothelial lipoprotein transport, inflammation, cellular transitions, and barrier function.

Summary

By using cutting-edge technologies such as single-cell sequencing, epigenetics, and cell fate mapping, novel regulatory mechanisms and endothelial cell phenotypes have been discovered, which have not only challenged established concepts of endothelial activation, but have also led to a different view of the disease.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

Caveolin-1 Regulates Cellular Metabolism: A Potential Therapeutic Target in Kidney Disease

The kidney is an energy-consuming organ, and cellular metabolism plays an indispensable role in kidney-related diseases. Caveolin-1 (Cav-1), a multifunctional membrane protein, is the main component of caveolae on the plasma membrane. Caveolae are represented by tiny invaginations that are abundant on the plasma membrane and that serve as a platform to regulate cellular endocytosis, stress responses, and signal transduction. However, caveolae have received increasing attention as a metabolic platform that mediates the endocytosis of albumin, cholesterol, and glucose, participates in cellular metabolic reprogramming and is involved in the progression of kidney disease. It is worth noting that caveolae mainly depend on Cav-1 to perform the abovementioned cellular functions. Furthermore, the mechanism by which Cav-1 regulates cellular metabolism and participates in the pathophysiology of kidney diseases has not been completely elucidated. In this review, we introduce the structure and function of Cav-1 and its functions in regulating cellular metabolism, autophagy, and oxidative stress, focusing on the relationship between Cav-1 in cellular metabolism and kidney disease; in addition, Cav-1 that serves as a potential therapeutic target for treatment of kidney disease is also described.

TLR4-Myd88 pathway upregulated caveolin-1 expression contributes to coronary artery spasm

AIM

To study the role of toll-like receptors 4-myeloid differentiation factor 88 (TLR4-Myd88) dependent caveolin-1 (Cav-1) expression modulation in coronary artery spasm (CAS) and explore the underlying pathogenic mechanisms.

METHODS AND RESULTS

Lipopolysaccharide (LPS) and acetylcholine (Ach) were used to develop the in vitro and in vivo models mimicking the physiological CAS microenvironment. LPS-induced upregulation of Cav-1 expression in mouse coronary and aorta endothelial cells was shown by western blot and immunofluorescence (IF) staining (p < 0.01). Caveolin-1-knockout (Cav-1^-/-) mice had reduced aortic inflammation after LPS challenge, and fewer ST segment changes were observed through electrocardiogram (ECG) monitoring compared to wild type mice after LPS and ACh administration. In vitro, pretreating human umbilical vein endothelial cells (HUVECs) with siCav-1 to knock down Cav-1 expression reduced the endothelial inflammation following LPS challenge. SiCav-1 also partially reversed the attenuated Ca²⁺ concentration after LPS and ACh administration compared to the control group, which was evaluated by fluorescent molecular probing for Ca²⁺ alternation monitoring (p < 0.05). TLR4 and Myd88 downregulation by siRNA partially blocked the increased Cav-1 mRNA and protein expressions following LPS treatment, as well as partially reversed the decreased NO production evaluated by nitrate reductase method and the impaired Ca²⁺ concentration of endothelial cells induced by LPS and ACh.

CONCLUSION

These findings suggested that Cav-1, which was upregulated by TLR4-Myd88, served as an important modulator of CAS microenvironment establishment in vivo and in vitro, making it a potential pharmacologic target for the treatment of vasospasm via reduced endothelial cell inflammation.

Role of caveolin-1 in chronic postsurgical pain in rats

Chronic postsurgical pain (CPSP) has a high incidence, but the underlying mechanisms remain elusive. Previous studies have indicated that caveolin-1 (Cav-1) plays a notable role in pain modulation. To study the role of Cav-1 in CPSP in the present study, a rat model of skin/muscle incision and retraction (SMIR) was established. Under anesthesia, skin and superficial muscle of the medial thigh were incised and a small pair of retractors inserted. It was revealed that SMIR increased the expression of Cav-1 in the dorsal root ganglion (DRG) and the injured tissue around the incision. Furthermore, the infiltration of endothelial cells and macrophages in the injured tissue around the incision increased constantly, and the vascular permeability increased due to the destruction of the vascular endothelial barrier function around the injured tissue. Cav-1 was mainly expressed by CD68-positive macrophages and CD34-positive endothelial cells in the injured tissues around the incision, while it was also primarily localized in the medium and large neurofilament 200-positive neurons and a small number of calcitonin gene-related peptide- and isolectin B4-positive small and medium-sized neurons in the DRG. The results demonstrated that the sustained high expression levels of Cav-1 in the injured tissue around the incision could lead to the dysfunction of the vascular endothelial barrier and, thus, could induce the inflammatory response through the lipoprotein transport of endothelial cells, thereby resulting in peripheral sensitization. In addition, the sustained high expression levels of Cav-1 in the DRG could sensitize large-sized neurons and change the transmission mode of noxious stimuli. The findings of the present study indicated that a Cav-1-mediated process could participate in neuronal transmission pathways associated with pain modulation.

Porphyromonas gingivalis facilitated the foam cell formation via lysosomal integral membrane protein 2 (LIMP2)

OBJECTIVE

The involvement of lysosomal integral membrane protein 2 (LIMP2) in cholesterol transport and formation of foam cells under the infection of Porphyromonas gingivalis (P. gingivalis) is yet to be elucidated. The current study verified the role and explored the mechanism of LIMP2 in promoting foam cell formation by P. gingivalis.

BACKGROUND

An association between periodontitis and atherosclerosis (AS) has been established. P. gingivalis is a key pathogen of periodontitis that promotes foam cell formation by regulating activities of CD36 scavenger receptors expressed on the macrophages. LIMP2, a member of CD36 superfamily, is involved in cholesterol efflux. However, whether LIMP2 is involved in the formation of foam cells promoted by P. gingivalis remains unclear.

METHODS

The formation of foam cells was examined by Oil Red O staining. The knockdown of limp2 was identified by qRT-PCR. The accumulation of cholesterol was monitored by Cholesterol Assay Kit. The location of P. gingivalis was visualized by confocal microscopy. Cathepsin L activity was monitored with Magic Red Cathepsin L Assay Kit. The key genes and pathways in P. gingivalis-infected macrophages were explored by RNA sequencing. The protein level was investigated by Western blotting.

RESULTS

Porphyromonas gingivalis increases foam cells formation and upregulates the expression of LIMP2 in foam cells. The knockdown of limp2 decreases the number of foam cells and increases cholesterol export, which is related to lysosomal functions. In addition, the interaction between LIMP2 and caveolin-1(CAV1) might contribute to this process, and NF-κB and JNK activity is required for increased expression of P. gingivalis-induced LIMP2.

CONCLUSIONS

This study suggested that LIMP2 is involved in the foam cells formation facilitated by P. gingivalis, which favors a close connection between periodontitis and atherosclerosis (AS).

LncRNA IMFlnc1 promotes porcine intramuscular adipocyte adipogenesis by sponging miR-199a-5p to up-regulate CAV-1

Background

Local Chinese local pig breeds have thinner muscle fiber and higher intramuscular-fat (IMF) content. But its regulation mechanism has not been discussed in-depth. Studies indicated that long non coding RNAs (lncRNAs) play important role in muscle and fat development.

Results

The lncRNAs expressional differences in the longissimus dorsi (LD) muscle were identified between Huainan pigs (local Chinese pigs, fat-type, HN) and Large White pigs (lean-type, LW) at 38, 58, and 78 days post conception (dpc). In total, 2131 novel lncRNAs were identified in 18 samples, and 291, 305, and 683 differentially expressed lncRNAs (DELs) were found between these two breeds at three stages, respectively. The mRNAs that co-expressed with these DELs were used for GO and KEGG analysis, and the results showed that muscle development and energy metabolism were more active at 58 dpc in HN, but at 78 dpc in LW pigs. Muscle cell differentiation and myofibril assembly might associated with earlier myogenesis and primary-muscle-fiber assembly in HN, and cell proliferation, insulin, and the MAPK pathway might be contribute to longer proliferation and elevated energy metabolism in LW pigs at 78 dpc. The PI3K/Akt and cAMP pathways were associated with higher IMF deposition in HN. Intramuscular fat deposition-associated long noncoding RNA 1 (IMFlnc1) was selected for functional verification, and results indicated that it regulated the expressional level of caveolin-1 (CAV-1) by acting as competing endogenous RNA (ceRNA) to sponge miR-199a-5p.

Conclusions

Our data contributed to understanding the role of lncRNAs in porcine-muscle development and IMF deposition, and provided valuable information for improving pig-meat quality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-020-00324-8.

Transendothelial transport of lipoproteins

The accumulation of low-density lipoproteins (LDL) in the arterial wall plays a pivotal role in the initiation and pathogenesis of atherosclerosis. Conversely, the removal of cholesterol from the intima by cholesterol efflux to high density lipoproteins (HDL) and subsequent reverse cholesterol transport shall confer protection against atherosclerosis. To reach the subendothelial space, both LDL and HDL must cross the intact endothelium. Traditionally, this transit is explained by passive filtration. This dogma has been challenged by the identification of several rate-limiting factors namely scavenger receptor SR-BI, activin like kinase 1, and caveolin-1 for LDL as well as SR-BI, ATP binding cassette transporter G1, and endothelial lipase for HDL. In addition, estradiol, vascular endothelial growth factor, interleukins 6 and 17, purinergic signals, and sphingosine-1-phosphate were found to regulate transendothelial transport of either LDL or HDL. Thorough understanding of transendothelial lipoprotein transport is expected to elucidate new therapeutic targets for the treatment or prevention of atherosclerotic cardiovascular disease and the development of strategies for the local delivery of drugs or diagnostic tracers into diseased tissues including atherosclerotic lesions.

Caveolin as a Novel Potential Therapeutic Target in Cardiac and Vascular Diseases: A Mini Review

Caveolin, a structural protein of caveolae, play roles in the regulation of endothelial function, cellular lipid homeostasis, and cardiac function by affecting the activity and biogenesis of nitric oxide, and by modulating signal transduction pathways that mediate inflammatory responses and oxidative stress. In this review, we present the role of caveolin in cardiac and vascular diseases and the relevant signaling pathways involved. Furthermore, we discuss a novel therapeutic perspective comprising crosstalk between caveolin and autophagy.

Urotensin II: an inflammatory cytokine

Urotensin II (UII) is a polypeptide molecule with neurohormone-like activity. It has been confirmed that UII is widely distributed in numerous organs of different animal species from fish to mammals, including humans. The UII receptor is orphan G-protein coupled receptor 14, also known as UT. The tissue distribution of UII and UT is highly consistent, and their expression may be regulated by autocrine and paracrine mechanisms. In the body, UII has many physiological and pathophysiological activities, such as vasoconstrictor and vasodilatory actions, cell proliferation, pro-fibrosis, neuroendocrine activity, insulin resistance, and carcinogenic and inflammatory effects, which have been recognized only in recent years. In fact, UII is involved in the process of inflammatory injury and plays a key role in the onset and development of inflammatory diseases. In this paper, we will review the roles UII plays in inflammatory diseases.