Role of JNK, p38, and ERK in platelet-derived growth factor-induced vascular proliferation, migration, and gene expression

Coordinated differentiation of human intestinal organoids with functional enteric neurons and vasculature

Human intestinal organoids (HIOs) derived from human pluripotent stem cells co-differentiate both epithelial and mesenchymal lineages in vitro but lack important cell types such as neurons, endothelial cells, and smooth muscle, which limits translational potential. Here, we demonstrate that the intestinal stem cell niche factor, EPIREGULIN (EREG), enhances HIO differentiation with epithelium, mesenchyme, enteric neuroglial populations, endothelial cells, and organized smooth muscle in a single differentiation, without the need for co-culture. When transplanted into a murine host, HIOs mature and demonstrate enteric nervous system function, undergoing peristaltic-like contractions indicative of a functional neuromuscular unit. HIOs also form functional vasculature, demonstrated in vitro using microfluidic devices and in vivo following transplantation, where HIO endothelial cells anastomose with host vasculature. These complex HIOs represent a transformative tool for translational research in the human gut and can be used to interrogate complex diseases as well as for testing therapeutic interventions with high fidelity to human pathophysiology.

Characterization of Protein Expression and Signaling Pathway Activation That May Contribute to Differential Biological Functions in Porcine Arterial and Venous Smooth Muscle Cells

Arteriovenous fistulae (AVF) are the preferred mode of dialysis vascular access but have a maturation failure rate of over 50%. Venous segment stenosis is one of the main reasons. However, the reasons for the prevalence of stenosis in the venous segment, as opposed to the arterial segment, remain unknown. We hypothesize that differences in the protein expression profiles and in the activation of key signaling pathways of the vascular smooth muscle cells (VSMCs) in these two segments may contribute to this difference. In this study, arterial porcine VSMCs (ApSMCs) and venous porcine VSMCs (VpSMCs) were isolated to examine relevant protein expression and cell signaling pathway activation via Western blots and immunofluorescent staining. Our results revealed that growth-medium-stimulated cell proliferation was significantly higher in VpSMCs compared to ApSMCs, but no difference was detected in PDGF-BB-stimulated proliferation. VpSMCs migration was significantly greater than ApSMCs under both the serum-free condition and in the growth medium condition. In addition, VpSMCs appeared more susceptible to PDGF-BB-stimulated cell dedifferentiation. Furthermore, P53, vitronectin, collagen 1A1 and integrin β3 had lower expression in VpSMCs, whereas fibronectin, FAK, VCAM-1, MMP-9, TIMP-2 and TIMP-3 had higher expression as compared to ApSMCs. Meanwhile, PDGF-BB stimulated P38, JNKs and AKT activation, which were more potent in VpSMCs. Our results identify significant differences between VpSMCs and ApSMCs in the expression of functional proteins and the activation of signaling pathways, which may be responsible for more aggressive venous-as compared to arterial-stenosis in the clinical setting of arteriovenous access or other similar procedures.

Bioactive milk-derived nutrient MFG-E8 ameliorates skeletal muscle atrophy induced by mitochondria damage in aging rats via activating the MAPK/ERK signaling pathway

Sarcopenia is the age-related loss of muscle and fiber number and decreased regenerative capacity with increased abundance of reactive oxygen species levels and electron transport chain abnormalities. The aim of this study was to investigate the antisarcopenia effect of MFG-E8 in alleviating skeletal muscle dysfunction induced by D-galactose, and reveal the mechanism promoting myoblast cell proliferation and mediating the cell cycle. This in vivo experiment showed that MFG-E8 can improve the antioxidant status and increase soleus muscle mass (35.61%) and fiber diameter (39.72%) in the aging rats. The western blot assay preliminarily proved that increased ERK phosphorylation determines the repairment of injured skeletal muscle, but not JNK and p38. In vitro experiments further verified that MFG-E8 can increase the number of mitochondria, cell vitality, cell density, and reduce apoptosis rate. Flow cytometry and quantitative real-time PCR proved that MFG-E8 promoted cell proliferation by upregulating mRNA expression of cyclin D1, cyclin E1, CDK, and downregulating mRNA expression of p21 and p27, thereby increasing the S and G2/M phase and decreasing the G0/G1 phase. Molecular level further proved that MFG-E8 mediated cell cycle and promoted cell proliferation by activating the MAPK/ERK signaling pathway.

Inositol 1,4,5-Trisphosphate Receptors Regulate Vascular Smooth Muscle Cell Proliferation and Neointima Formation in Mice

BACKGROUND

Vascular smooth muscle cell (VSMC) proliferation is involved in many types of arterial diseases, including neointima hyperplasia, in which Ca2+ has been recognized as a key player. However, the physiological role of Ca2+ release via inositol 1,4,5-trisphosphate receptors (IP3Rs) from endoplasmic reticulum in regulating VSMC proliferation has not been well determined.

METHODS AND RESULTS

Both in vitro cell culture models and in vivo mouse models were generated to investigate the role of IP3Rs in regulating VSMC proliferation. Expression of all 3 IP3R subtypes was increased in cultured VSMCs upon platelet-derived growth factor-BB and FBS stimulation as well as in the left carotid artery undergoing intimal thickening after vascular occlusion. Genetic ablation of all 3 IP3R subtypes abolished endoplasmic reticulum Ca2+ release in cultured VSMCs, significantly reduced cell proliferation induced by platelet-derived growth factor-BB and FBS stimulation, and also decreased cell migration of VSMCs. Furthermore, smooth muscle-specific deletion of all IP3R subtypes in adult mice dramatically attenuated neointima formation induced by left carotid artery ligation, accompanied by significant decreases in cell proliferation and matrix metalloproteinase-9 expression in injured vessels. Mechanistically, IP3R-mediated Ca2+ release may activate cAMP response element-binding protein, a key player in controlling VSMC proliferation, via Ca2+/calmodulin-dependent protein kinase II and Akt. Loss of IP3Rs suppressed cAMP response element-binding protein phosphorylation at Ser133 in both cultured VSMCs and injured vessels, whereas application of Ca2+ permeable ionophore, ionomycin, can reverse cAMP response element-binding protein phosphorylation in IP3R triple knockout VSMCs.

CONCLUSIONS

Our results demonstrated an essential role of IP3R-mediated Ca2+ release from endoplasmic reticulum in regulating cAMP response element-binding protein activation, VSMC proliferation, and neointima formation in mouse arteries.

Curative effects and mechanisms of AG1296 and LY294002 co-therapy in Angiostrongylus cantonensis-induced neurovascular unit dysfunction and eosinophilic meningoencephalitis

BACKGROUND

Co-therapy with albendazole and steroid is commonly used in patients with eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis infections. However, anthelminthics often worsen symptoms, possibly due to the inflammatory reaction to antigens released by dying worms. Therefore, the present study was to investigate the curative effects and probable mechanisms of the platelet-derived growth factor receptor-beta (PDGFR-β) inhibitor AG1296 (AG) and the phosphoinositide 3-kinase inhibitor (PI3K) LY294002 (LY) in A. cantonensis-induced neurovascular unit dysfunction and eosinophilic meningoencephalitis.

METHODS

Western blots were used to detect matrix protein degradation and the expressions of PDGFR-β/PI3K signaling pathway. The co-localization of PDGFR-β and vascular smooth muscle cells (VSMCs), and metalloproteinase-9 (MMP-9) and VSMCs on the blood vessels were measured by confocal laser scanning immunofluorescence microscopy. Sandwich enzyme-linked immunosorbent assays were used to test S100B, interleukin (IL)-6, and transforming growth factor beta in the cerebrospinal fluid to determine their possible roles in mouse resistance to A. cantonensis.

RESULTS

The results showed that AG and LY cotherapy decreased the MMP-9 activity and inflammatory reaction. Furthermore, S100B, IL-6 and eosinophil counts were reduced by inhibitor treatment. The localization of PDGFR-β and MMP-9 was observed in VSMCs. Furthermore, we showed that the degradation of the neurovascular matrix and blood-brain barrier permeability were reduced in the mouse brain.

CONCLUSIONS

These findings demonstrate the potential of PDGFR-β inhibitor AG and PI3K inhibitor LY co-therapy as anti-A. cantonensis drug candidates through improved neurovascular unit dysfunction and reduced inflammatory response.

Research advances in cochlear pericytes and hearing loss

Pericytes are specialized mural cells surrounding endothelial cells in microvascular beds. They play a role in vascular development, blood flow regulation, maintenance of blood-tissue barrier integrity, and control of angiogenesis, tissue fibrosis, and wound healing. In recent decades, understanding of the critical role played by pericytes in retina, brain, lung, and kidney has seen significant progress. The cochlea contains a large population of pericytes. However, the role of cochlear pericytes in auditory pathophysiology is, by contrast, largely unknown. The present review discusses recent progress in identifying cochlear pericytes, mapping their distribution, and defining their role in regulating blood flow, controlling the blood-labyrinth barrier (BLB) and angiogenesis, and involvement in different types of hearing loss.

Hypercholesterolemic Dysregulation of Calpain in Lymphatic Endothelial Cells Interferes With Regulatory T-Cell Stability and Trafficking

BACKGROUND

Although hypercholesterolemia reportedly counteracts lymphocyte trafficking across lymphatic vessels, the roles of lymphatic endothelial cells (LECs) in the lymphocyte regulations remain unclear. Previous studies showed that calpain-an intracellular modulatory protease-interferes with leukocyte dynamics in the blood microcirculation and is associated with hypercholesterolemic dysfunction in vascular endothelial cells.

METHODS

This study investigated whether the calpain systems in LECs associate with the LEC-lymphocyte interaction under hypercholesterolemia using gene-targeted mice.

RESULTS

Lipidomic analysis in hypercholesterolemic mice showed that several lysophospholipids, including lysophosphatidic acid, accumulated in the lymphatic environment. Lysophosphatidic acid enables the potentiation of calpain systems in cultured LECs, which limits their ability to stabilize regulatory T cells (Treg) without altering Th1/Th2 (T helper type1/2) subsets. This occurs via the proteolytic degradation of MEKK1 (mitogen-activated protein kinase kinase kinase 1) and the subsequent inhibition of TGF (transforming growth factor)-β1 production in LECs. Targeting calpain systems in LECs expanded Tregs in the blood circulation and reduced aortic atherosclerosis in hypercholesterolemic mice, concomitant with the reduction of proinflammatory macrophages in the lesions. Treg expansion in the blood circulation and atheroprotection in calpain-targeted mice was prevented by the administration of TGF-β type-I receptor inhibitor. Moreover, lysophosphatidic acid-induced calpain overactivation potentiated the IL (interleukin)-18/NF-κB (nuclear factor κB)/VCAM1 (vascular cell adhesion molecule 1) axis in LECs, thereby inhibiting lymphocyte mobility on the cells. Indeed, VCAM1 in LECs was upregulated in hypercholesterolemic mice and human cases of coronary artery disease. Neutralization of VCAM1 or targeting LEC calpain systems recovered afferent Treg transportation via lymphatic vessels in mice.

CONCLUSIONS

Calpain systems in LECs have a key role in controlling Treg stability and trafficking under hypercholesterolemia.

Inhibitory effects of 6'-sialyllactose on angiotensin II-induced proliferation, migration, and osteogenic switching in vascular smooth muscle cells

Excessive production and migration of vascular smooth muscle cells (VSMCs) are associated with vascular remodeling that causes vascular diseases, such as restenosis and hypertension. Angiotensin II (Ang II) stimulation is a key factor in inducing abnormal VSMC function. This study aimed to investigate the effects of 6'-sialyllactose (6'SL), a human milk oligosaccharide, on Ang II-stimulated cell proliferation, migration and osteogenic switching in rat aortic smooth muscle cells (RASMCs) and human aortic smooth muscle cells (HASMCs). Compared with the control group, Ang II increased cell proliferation by activating MAPKs, including ERK1/2/p90RSK/Akt/mTOR and JNK pathways. However, 6'SL reversed Ang II-stimulated cell proliferation and the ERK1/2/p90RSK/Akt/mTOR pathways in RASMCs and HASMCs. Moreover, 6'SL suppressed Ang II-stimulated cell cycle progression from G0/G1 to S and G2/M phases in RASMCs. Furthermore, 6'SL effectively inhibited cell migration by downregulating NF-κB-mediated MMP2/9 and VCAM-1 expression levels. Interestingly, in RASMCs, 6'SL attenuated Ang II-induced osteogenic switching by reducing the production of p90RSK-mediated c-fos and JNK-mediated c-jun, leading to the downregulation of AP-1-mediated osteopontin production. Taken together, our data suggest that 6'SL inhibits Ang II-induced VSMC proliferation and migration by abolishing the ERK1/2/p90RSK-mediated Akt and NF-κB signaling pathways, respectively, and osteogenic switching by suppressing p90RSK- and JNK-mediated AP-1 activity.

Sex differences in arterial identity correlate with neointimal hyperplasia after balloon injury

BACKGROUND

Endovascular treatment of atherosclerotic arterial disease exhibits sex differences in clinical outcomes including restenosis. However, sex-specific differences in arterial identity during arterial remodeling have not been described. We hypothesized that sex differences in expression of the arterial determinant erythropoietin-producing hepatocellular receptor interacting protein (Ephrin)-B2 occur during neointimal proliferation and arterial remodeling.

METHODS AND RESULTS

Carotid balloon injury was performed in female and male Sprague-Dawley rats without or 14 days after gonadectomy; the left common carotid artery was injured and the right carotid artery in the same animal was used as an uninjured control. Arterial hemodynamics were evaluated in vivo using ultrasonography pre-procedure and post-procedure at 7 and 14 days and wall composition examined using histology, immunofluorescence and Western blot at 14 days after balloon injury. There were no significant baseline sex differences. 14 days after balloon injury, there was decreased neointimal thickness in female rats with decreased smooth muscle cell proliferation and decreased type I and III collagen deposition, as well as decreased TNFα- or iNOS-positive CD68+ cells and increased CD206- or TGM2-positive CD68+ cells. Female rats also showed less immunoreactivity of VEGF-A, NRP1, phosphorylated EphrinB2, and increased Notch1, as well as decreased phosphorylated Akt1, p38 and ERK1/2. These differences were not present in rats pretreated with gonadectomy.

CONCLUSIONS

Decreased neointimal thickness in female rats after carotid balloon injury is associated with altered arterial identity that is dependent on intact sex hormones. Alteration of arterial identity may be a mechanism of sex differences in neointimal proliferation after arterial injury.

Oxidative stress: An essential factor in the process of arteriovenous fistula failure

For more than half a century, arteriovenous fistula (AVFs) has been recognized as a lifeline for patients requiring hemodialysis (HD). With its higher long-term patency rate and lower probability of complications, AVF is strongly recommended by guidelines in different areas as the first choice for vascular access for HD patients, and its proportion of application is gradually increasing. Despite technological improvements and advances in the standards of postoperative care, many deficiencies are still encountered in the use of AVF related to its high incidence of failure due to unsuccessful maturation to adequately support HD and the development of neointimal hyperplasia (NIH), which narrows the AVF lumen. AVF failure is linked to the activation and migration of vascular cells and the remodeling of the extracellular matrix, where complex interactions between cytokines, adhesion molecules, and inflammatory mediators lead to poor adaptive remodeling. Oxidative stress also plays a vital role in AVF failure, and a growing amount of data suggest a link between AVF failure and oxidative stress. In this review, we summarize the present understanding of the pathophysiology of AVF failure. Furthermore, we focus on the relation between oxidative stress and AVF dysfunction. Finally, we discuss potential therapies for addressing AVF failure based on targeting oxidative stress.

Riboflavin ameliorates mitochondrial dysfunction via the AMPK/PGC1α/HO‑1 signaling pathway and attenuates carbon tetrachloride‑induced liver fibrosis in rats

Hepatic fibrosis is a global health problem, with increasing evidence demonstrating that oxidative stress serves a pivotal role in fibrogenesis. Riboflavin is a vital nutrient in the human and animal diet, which enhances the activity of antioxidant enzymes and ameliorates oxidative stress. The present study evaluated the effect of riboflavin on liver fibrosis and the mechanisms underlying this process. Rats were subcutaneously injected with carbon tetrachloride (CCl₄) dissolved in sterile olive oil twice per week to induce hepatic fibrosis. The effect of riboflavin on CCl₄-induced liver fibrosis was then assessed. Blood samples and liver tissues were collected and analyzed. The liver tissue morphological changes, immunohistochemical analysis, levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in the mitochondria, and the protein expression levels of α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), extracellular signal-regulated kinase (ERK), p38, c-Jun N-terminal kinase (JNK), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and heme oxygenase 1 (HO-1) in the liver were also analyzed. The results demonstrated that riboflavin treatment significantly decreased the levels of alanine transaminase and aspartate transaminase in the serum, increased SOD activity and modulated the MDA level in the mitochondria. Furthermore, riboflavin significantly inhibited the CCl₄-induced, upregulated protein expression levels of phosphorylated (p)-ERK, p-p38, p-JNK, TGF-β1 and α-SMA. Moreover, riboflavin significantly increased the expression of p-AMPK, PGC-1α and HO-1 in the liver tissue. These results suggested that riboflavin delays CCl₄-induced hepatic fibrosis by enhancing the mitochondrial function via the AMPK/PGC-1α/HO-1 and mitogen-activated protein kinase signaling pathways.

Activation of the GTPase ARF6 regulates invasion of human vascular smooth muscle cells by stimulating MMP14 activity

Hormones and growth factors stimulate vascular smooth muscle cells (VSMC) invasive capacities during the progression of atherosclerosis. The GTPase ARF6 is an important regulator of migration and proliferation of various cell types, but whether this small G protein can be activated by a variety of stimuli to promote invasion of VSMC remains unknown. Here, we aimed to define whether Platelet-derived growth factor (PDGF), a mitogenic stimulant of vascular tissues, and Angiotensin II (Ang II), a potent vasoactive peptide, can result in the activation of ARF6 in a human model of aortic SMC (HASMC). We demonstrate that these two stimuli can promote loading of GTP on this ARF isoform. Knockdown of ARF6 reduced the ability of both PDGF and Ang II to promote invasion suggesting that this GTPase regulates key molecular mechanisms mediating degradation of the extracellular matrix and migration. We report that PDGF-BB-mediated stimulation of ARF6 results in the activation of the MAPK/ERK1/2, PI3K/AKT and PAK pathways essential for invasion of HASMC. However, Ang II-mediated stimulation of ARF6 only promotes signaling through the MAPK/ERK1/2 and PAK pathways. These ARF6-mediated events lead to activation of MMP14, a membrane-bound collagenase upregulated in atherosclerosis. Moreover, ARF6 depletion decreases the release of MMP2 in the extracellular milieu. Altogether, our findings demonstrate that the GTPase ARF6 acts as a molecular switch to regulate specific signaling pathways that coordinate invasiveness of HASMC.

CFTR Suppresses Neointimal Formation Through Attenuating Proliferation and Migration of Aortic Smooth Muscle Cells

ABSTRACT

Cystic fibrosis transmembrane conductance regulator (CFTR) plays important roles in arterial functions and the fate of cells. To further understand its function in vascular remodeling, we examined whether CFTR directly regulates platelet-derived growth factor-BB (PDGF-BB)-stimulated vascular smooth muscle cells (VSMCs) proliferation and migration, as well as the balloon injury-induced neointimal formation. The CFTR adenoviral gene delivery was used to evaluate the effects of CFTR on neointimal formation in a rat model of carotid artery balloon injury. The roles of CFTR in PDGF-BB-stimulated VSMC proliferation and migration were detected by mitochondrial tetrazolium assay, wound healing assay, transwell chamber method, western blot, and qPCR. We found that CFTR expression was declined in injured rat carotid arteries, while adenoviral overexpression of CFTR in vivo attenuated neointimal formation in carotid arteries. CFTR overexpression inhibited PDGF-BB-induced VSMC proliferation and migration, whereas CFTR silencing caused the opposite results. Mechanistically, CFTR suppressed the phosphorylation of PDGF receptor β, serum and glucocorticoid-inducible kinase 1, JNK, p38 and ERK induced by PDGF-BB, and the increased mRNA expression of matrix metalloproteinase-9 and MMP2 induced by PDGF-BB. In conclusion, our results indicated that CFTR may attenuate neointimal formation by suppressing PDGF-BB-induced activation of serum and glucocorticoid-inducible kinase 1 and the JNK/p38/ERK signaling pathway.

p38 MAPK priming boosts VSMC proliferation and arteriogenesis by promoting PGC1α-dependent mitochondrial dynamics

Vascular smooth muscle cell (VSMC) proliferation is essential for arteriogenesis to restore blood flow after artery occlusion, but the mechanisms underlying this response remain unclear. Based on our previous findings showing increased VSMC proliferation in the neonatal aorta of mice lacking the protease MT4-MMP, we aimed at discovering new players in this process. We demonstrate that MT4-MMP absence boosted VSMC proliferation in vitro in response to PDGF-BB in a cell-autonomous manner through enhanced p38 MAPK activity. Increased phospho-p38 in basal MT4-MMP-null VSMCs augmented the rate of mitochondrial degradation by promoting mitochondrial morphological changes through the co-activator PGC1α as demonstrated in PGC1α^−/− VSMCs. We tested the in vivo implications of this pathway in a novel conditional mouse line for selective MT4-MMP deletion in VSMCs and in mice pre-treated with the p38 MAPK activator anisomycin. Priming of p38 MAPK activity in vivo by the absence of the protease MT4-MMP or by anisomycin treatment led to enhanced arteriogenesis and improved flow recovery after femoral artery occlusion. These findings may open new therapeutic opportunities for peripheral vascular diseases.

Repeated Social Defeat Enhances CaCl2-Induced Abdominal Aortic Aneurysm Expansion by Inhibiting the Early Fibrotic Response via the MAPK-MKP-1 Pathway

Depression is an independent risk factor for cardiovascular disease and is significantly associated with the prevalence of abdominal aortic aneurysm (AAA). We investigated the effect of repeated social defeat (RSD) on AAA development. Eight-week-old male wild-type mice were exposed to RSD by being housed with larger CD-1 mice in a shared cage. They were subjected to vigorous physical contact. After the confirmation of depressive-like behavior, calcium chloride was applied to the infrarenal aorta of the mice. At one week, AAA development was comparable between the defeated and control mice, without any differences being observed in the accumulated macrophages or in the matrix metalloproteinase activity. At two weeks, the maximum diameter and circumference of the aneurysm were significantly increased in the defeated mice, and a significant decrease in periaortic fibrosis was also observed. Consistently, the phosphorylation of the extracellular signal-regulated kinase and the incorporation of 5-bromo-2'-deoxyuridine in the primarily cultured aortic vascular smooth muscle cells were significantly reduced in the defeated mice, which was accompanied by a substantial increase in mitogen-activated protein kinase phosphatase-1 (MKP-1). The MKP-1 mRNA and protein expression levels during AAA were much higher in the defeated mice than they were in the control mice. Our findings demonstrate that RSD enhances AAA development by suppressing periaortic fibrosis after an acute inflammatory response and imply novel mechanisms that are associated with depression-related AAA development.

Myricanol Inhibits Platelet Derived Growth Factor-BB-Induced Vascular Smooth Muscle Cells Proliferation and Migration in vitro and Intimal Hyperplasia in vivo by Targeting the Platelet-Derived Growth Factor Receptor-β and NF-κB Signaling

The abnormal proliferation and migration of Vascular smooth muscle cells (VSMCs) are related to many cardiovascular diseases, including atherosclerosis, restenosis after balloon angioplasty, hypertension, etc. Myricanol is a diarylheptanoid that can be separated from the bark of Myrica rubra. It has been reported that myricanol can anti-inflammatory, anti-cancer, anti-neurodegenerative, promote autophagic clearance of tau and prevent muscle atrophy. But its potential role in the cardiovascular field remains unknown. In this study, we investigated the effect of myricanol on the proliferation and migration of VSMCs in vitro and on the intimal hyperplasia in vivo. In vitro experiments, we found myricanol can inhibit the proliferation and migration of VSMCs induced by PDGF-BB. In terms of mechanism, the preincubation of myricanol can suppress the PDGF-BB induced phosphorylation of PDGFRβ and its downstream such as PLCγ1, Src, and MAPKs. In addition, NF-kB p65 translocation was also suppressed by myricanol. In vivo experiments, we found myricanol can suppress the intimal hyperplasia after wire ligation of the carotid artery in mice. These results may provide a new strategy for the prevention and treatment of coronary atherosclerosis and post-stent stenosis in the future.

MAPK/ERK Pathway as a Central Regulator in Vertebrate Organ Regeneration

Damage to organs by trauma, infection, diseases, congenital defects, aging, and other injuries causes organ malfunction and is life-threatening under serious conditions. Some of the lower order vertebrates such as zebrafish, salamanders, and chicks possess superior organ regenerative capacity over mammals. The extracellular signal-regulated kinases 1 and 2 (ERK1/2), as key members of the mitogen-activated protein kinase (MAPK) family, are serine/threonine protein kinases that are phylogenetically conserved among vertebrate taxa. MAPK/ERK signaling is an irreplaceable player participating in diverse biological activities through phosphorylating a broad variety of substrates in the cytoplasm as well as inside the nucleus. Current evidence supports a central role of the MAPK/ERK pathway during organ regeneration processes. MAPK/ERK signaling is rapidly excited in response to injury stimuli and coordinates essential pro-regenerative cellular events including cell survival, cell fate turnover, migration, proliferation, growth, and transcriptional and translational activities. In this literature review, we recapitulated the multifaceted MAPK/ERK signaling regulations, its dynamic spatio-temporal activities, and the profound roles during multiple organ regeneration, including appendages, heart, liver, eye, and peripheral/central nervous system, illuminating the possibility of MAPK/ERK signaling as a critical mechanism underlying the vastly differential regenerative capacities among vertebrate species, as well as its potential applications in tissue engineering and regenerative medicine.

Anti-Inflammatory Effects of Rhamnetin on Bradykinin-Induced Matrix Metalloproteinase-9 Expression and Cell Migration in Rat Brain Astrocytes

Bradykinin (BK) has been shown to induce matrix metalloproteinase (MMP)-9 expression and participate in neuroinflammation. The BK/MMP-9 axis can be a target for managing neuroinflammation. Our previous reports have indicated that reactive oxygen species (ROS)-mediated nuclear factor-kappaB (NF-κB) activity is involved in BK-induced MMP-9 expression in rat brain astrocytes (RBA-1). Rhamnetin (RNT), a flavonoid compound, possesses antioxidant and anti-inflammatory effects. Thus, we proposed RNT could attenuate BK-induced response in RBA-1. This study aims to approach mechanisms underlying RNT regulating BK-stimulated MMP-9 expression, especially ROS and NF-κB. We used pharmacological inhibitors and siRNAs to dissect molecular mechanisms. Western blotting and gelatin zymography were used to evaluate protein and MMP-9 expression. Real-time PCR was used for gene expression. Wound healing assay was applied for cell migration. 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) were used for ROS generation and NOX activity, respectively. Promoter luciferase assay and chromatin immunoprecipitation (ChIP) assay were applied to detect gene transcription. Our results showed that RNT inhibits BK-induced MMP-9 protein and mRNA expression, promoter activity, and cell migration in RBA-1 cells. Besides, the levels of phospho-PKCδ, NOX activity, ROS, phospho-ERK1/2, phospho-p65, and NF-κB p65 binding to MMP-9 promoter were attenuated by RNT. In summary, RNT attenuates BK-enhanced MMP-9 upregulation through inhibiting PKCδ/NOX/ROS/ERK1/2-dependent NF-κB activity in RBA-1.

microRNA-19b-3p-containing extracellular vesicles derived from macrophages promote the development of atherosclerosis by targeting JAZF1

Atherosclerosis has been regarded as a major contributor to cardiovascular disease. The role of extracellular vesicles (EVs) in the treatment of atherosclerosis has been increasingly reported. In this study, we set out to investigate the effect of macrophages‐derived EVs (M‐EVs) containing miR‐19b‐3p in the progression of atherosclerosis, with the involvement of JAZF1. Following isolation of EVs from macrophages, the M‐EVs were induced with ox‐low density lipoprotein (LDL) (ox‐LDL‐M‐EVs), and co‐cultured with vascular smooth muscle cells (VSMCs). RT‐qPCR and western blot assay were performed to determine the expression of miR‐19b‐3p and JAZF1 in M‐EVs and in VSMCs. Lentiviral infection was used to overexpress or knock down miR‐19b‐3p. EdU staining and scratch test were conducted to examine VSMC proliferation and migration. Dual‐luciferase gene reporter assay was performed to examine the relationship between miR‐19b‐3p and JAZF1. In order to explore the role of ox‐LDL‐M‐EVs carrying miR‐19b‐3p in atherosclerotic lesions in vivo, a mouse model of atherosclerosis was established through high‐fat diet induction. M‐EVs were internalized by VSMCs. VSMC migration and proliferation were promoted by ox‐LDL‐M‐EVs. miR‐19b‐3p displayed upregulation in ox‐LDL‐M‐EVs. miR‐19b‐3p was transferred by M‐EVs into VSMCs, thereby promoting VSMC migration and proliferation. mir‐19b‐3p targeted JAZF1 to decrease its expression in VSMCs. Atherosclerosis lesions were aggravated by ox‐LDL‐M‐EVs carrying miR‐19b‐3p in ApoE^−/− mice. Collectively, this study demonstrates that M‐EVs containing miR‐19b‐3p accelerate migration and promotion of VSMCs through targeting JAZF1, which promotes the development of atherosclerosis.

Activation of EphrinB2 Signaling Promotes Adaptive Venous Remodeling in Murine Arteriovenous Fistulae

BACKGROUND

Arteriovenous fistulae (AVF) are the preferred mode of vascular access for hemodialysis. Before use, AVF remodel by thickening and dilating to achieve a functional conduit via an adaptive process characterized by expression of molecular markers characteristic of both venous and arterial identity. Although signaling via EphB4, a determinant of venous identity, mediates AVF maturation, the role of its counterpart EphrinB2, a determinant of arterial identity, remains unclear. We hypothesize that EphrinB2 signaling is active during AVF maturation and may be a mechanism of venous remodeling.

METHODS

Aortocaval fistulae were created or sham laparotomy was performed in C57Bl/6 mice, and specimens were examined on Days 7 or 21. EphrinB2 reverse signaling was activated with EphB4-Fc applied periadventitially in vivo and in endothelial cell culture medium in vitro. Downstream signaling was assessed using immunoblotting and immunofluorescence.

RESULTS

Venous remodeling during AVF maturation was characterized by increased expression of EphrinB2 as well as Akt1, extracellular signal-regulated kinases 1/2 (ERK1/2), and p38. Activation of EphrinB2 with EphB4-Fc increased phosphorylation of EphrinB2, endothelial nitric oxide synthase, Akt1, ERK1/2, and p38 and was associated with increased diameter and wall thickness in the AVF. Both mouse and human endothelial cells treated with EphB4-Fc increased phosphorylation of EphrinB2, endothelial nitric oxide synthase, Akt1, ERK1/2, and p38 and increased endothelial cell tube formation and migration.

CONCLUSIONS

Activation of EphrinB2 signaling by EphB4-Fc was associated with adaptive venous remodeling in vivo while activating endothelial cell function in vitro. Regulation of EphrinB2 signaling may be a new strategy to improve AVF maturation and patency.

Sorafenib Modulates the LPS- and Aβ-Induced Neuroinflammatory Response in Cells, Wild-Type Mice, and 5xFAD Mice

Sorafenib is FDA-approved for the treatment of primary kidney or liver cancer, but its ability to inhibit many types of kinases suggests it may have potential for treating other diseases. Here, the effects of sorafenib on neuroinflammatory responses in vitro and in vivo and the underlying mechanisms were assessed. Sorafenib reduced the induction of mRNA levels of the proinflammatory cytokines COX-2 and IL-1β by LPS in BV2 microglial cells, but in primary astrocytes, only COX-2 mRNA levels were altered by sorafenib. Interestingly, sorafenib altered the LPS-mediated neuroinflammatory response in BV2 microglial cells by modulating AKT/P38-linked STAT3/NF-kB signaling pathways. In LPS-stimulated wild-type mice, sorafenib administration suppressed microglial/astroglial kinetics and morphological changes and COX-2 mRNA levels by decreasing AKT phosphorylation in the brain. In 5xFAD mice (an Alzheimer’s disease model), sorafenib treatment daily for 3 days significantly reduced astrogliosis but not microgliosis. Thus, sorafenib may have therapeutic potential for suppressing neuroinflammatory responses in the brain.

Molecular Action of Hydroxytyrosol in Attenuation of Intimal Hyperplasia: A Scoping Review

Objective: Hydroxytyrosol (HT), a polyphenol of olive plant is well known for its antioxidant, anti-inflammatory and anti-atherogenic properties. The aim of this systematic search is to highlight the scientific evidence evaluating molecular efficiency of HT in halting the progression of intimal hyperplasia (IH), which is a clinical condition arises from endothelial inflammation. Methods: A systematic search was performed through PubMed, Web of Science and Scopus, based on pre-set keywords which are Hydroxytyrosol OR 3,4-dihydroxyphenylethanol, AND Intimal hyperplasia OR Neointimal hyperplasia OR Endothelial OR Smooth muscles. Eighteen in vitro and three in vitro and in vivo studies were selected based on a pre-set inclusion and exclusion criteria. Results: Based on evidence gathered, HT was found to upregulate PI3K/AKT/mTOR pathways and supresses inflammatory factors and mediators such as IL-1β, IL-6, E-selectin, P-selectin, VCAM-1, and ICAM-1 in endothelial vascularization and functioning. Two studies revealed HT disrupted vascular smooth muscle cells (SMC) cell cycle by dephosphorylating ERK1/2 and AKT pathways. Therefore, HT was proven to promote endothelization and inhibit vascular SMCs migration thus hampering IH development. However, none of these studies described the effect of HT collectively in both vascular endothelial cells (EC) and SMCs in IH ex vivo model. Conclusions: Evidence from this concise review provides an insight on HT regulation of molecular pathways in reendothelization and inhibition of VSMCs migration. Henceforth, we propose effect of HT on IH prevention could be further elucidated through in vivo and ex vivo model.

Identification and functional analysis of a biflavone as a novel inhibitor of transient receptor potential vanilloid 4-dependent atherogenic processes

Atherosclerosis, a chronic inflammatory disease of large arteries, is the major contributor to the growing burden of cardiovascular disease-related mortality and morbidity. During early atherogenesis, as a result of inflammation and endothelial dysfunction, monocytes transmigrate into the aortic intimal areas, and differentiate into lipid-laden foam cells, a critical process in atherosclerosis. Numerous natural compounds such as flavonoids and polyphenols are known to have anti-inflammatory and anti-atherogenic properties. Herein, using a fluorometric imaging plate reader-supported Ca2+ influx assay, we report semi high-throughput screening-based identification of ginkgetin, a biflavone, as a novel inhibitor of transient receptor potential vanilloid 4 (TRPV4)-dependent proatherogenic and inflammatory processes in macrophages. We found that ginkgetin (1) blocks TRPV4-elicited Ca2+ influx into macrophages, (2) inhibits oxidized low-density lipoprotein (oxLDL)-induced foam cell formation by suppressing the uptake but not the binding of oxLDL in macrophages, and (3) attenuates oxLDL-induced phosphorylation of JNK2, expression of TRPV4 proteins, and induction of inflammatory mRNAs. Considered all together, the results of this study show that ginkgetin inhibits proatherogenic/inflammatory macrophage function in a TRPV4-dependent manner, thus strengthening the rationale for the use of natural compounds for developing therapeutic and/or chemopreventive molecules.

Cytoprotective Role of Edible Seahorse (Hippocampus abdominalis)-Derived Peptides in H2O2-Induced Oxidative Stress in Human Umbilical Vein Endothelial Cells

Oxidative stress-induced endothelial dysfunction is strongly linked to the pathogenesis of cardiovascular diseases. A previous study revealed that seahorse hydrolysates ameliorated oxidative stress-mediated human umbilical vein endothelial cells (HUVECs) injury. However, the responsible compounds have not yet been identified. This study aimed to identify cytoprotective peptides and to investigate the molecular mechanism underlying the cytoprotective role in H₂O₂-induced HUVECs injury. After purification by gel filtration and HPLC, two peptides were sequenced by liquid chromatography-tandem mass spectrometry as HGSH (436.43 Da) and KGPSW (573.65 Da). The synthesized peptides and their combination (1:1 ratio) showed significant HUVECs protection effect at 100 μg/mL against H₂O₂-induced oxidative damage via significantly reducing intracellular reactive oxygen species (ROS). Two peptides and their combination treatment resulted in the increased heme oxygenase-1 (HO-1), a phase II detoxifying enzyme, through the activation of nuclear transcription factor-erythroid 2-related factor (Nrf2). Additionally, cell cycle and nuclear staining analysis revealed that two peptides and their combination significantly protected H₂O₂-induced cell death through antiapoptotic action. Two peptides and their combination treatment led to inhibit the expression of proapoptotic Bax, the release of cytochrome C into the cytosol, the activation of caspase 3 by H₂O₂ treatment in HUVECs, whereas antiapoptotic Bcl-2 expression was increased with concomitant downregulation of Bax/Bcl-2 ratio. Taken together, these results suggest that seahorse-derived peptides may be a promising agent for oxidative stress-related cardiovascular diseases.

Advanced In Vitro Modeling to Study the Paradox of Mechanically Induced Cardiac Fibrosis

In heart failure, cardiac fibrosis is the result of an adverse remodeling process. Collagen is continuously synthesized in the myocardium in an ongoing attempt of the heart to repair itself. The resulting collagen depositions act counterproductively, causing diastolic dysfunction and disturbing electrical conduction. Efforts to treat cardiac fibrosis specifically have not been successful and the molecular etiology is only partially understood. The differentiation of quiescent cardiac fibroblasts to extracellular matrix-depositing myofibroblasts is a hallmark of cardiac fibrosis and a key aspect of the adverse remodeling process. This conversion is induced by a complex interplay of biochemical signals and mechanical stimuli. Tissue-engineered 3D models to study cardiac fibroblast behavior in vitro indicate that cyclic strain can activate a myofibroblast phenotype. This raises the question how fibroblast quiescence is maintained in the healthy myocardium, despite continuous stimulation of ultimately profibrotic mechanotransductive pathways. In this review, we will discuss the convergence of biochemical and mechanical differentiation signals of myofibroblasts, and hypothesize how these affect this paradoxical quiescence. Impact statement Mechanotransduction pathways of cardiac fibroblasts seem to ultimately be profibrotic in nature, but in healthy human myocardium, cardiac fibroblasts remain quiescent, despite continuous mechanical stimulation. We propose three hypotheses that could explain this paradoxical state of affairs. Furthermore, we provide suggestions for future research, which should lead to a better understanding of fibroblast quiescence and activation, and ultimately to new strategies for the prevention and treatment of cardiac fibrosis and heart failure.

p38/JNK Is Required for the Proliferation and Phenotype Changes of Vascular Smooth Muscle Cells Induced by L3MBTL4 in Essential Hypertension

Aim

Hypertension is a complicated disorder with multifactorial etiology and high heritability. Our previous work has identified L3MBTL4 as a novel susceptibility gene for the development of essential hypertension, accompanied with activation of p38/JNK. Yet, little evidence has been reported whether p38/JNK contributed directly to L3MBTL4-induced vascular remodeling and exploring the potential mechanism of L3MBTL4 in vascular smooth muscle cells (VSMCs).

Methods

We evaluated the contribution of L3MBTL4 on proliferation, migration, and phenotype changes of VSMCs and further explored the critical role of p38 and JNK signaling pathway underlying.

Results

In L3MBTL4 transgenic rats, we found that the elevated blood pressure, increased left ventricular hypertrophy, and thickened vascular media layer were significantly relieved by both p38 and JNK inhibitors. Meanwhile, increased cell proliferation, advanced cell cycle progression, greater migratory capability, and synthetic phenotype were observed in L3MBTL4 overexpressed VSMCs, which could be blocked by either p38 or JNK inhibitor.

Conclusions

Our findings pinpointed that p38 and JNK were required for the proliferation and phenotype changes of VSMCs induced by L3MBTL4 in hypertension. These novel findings yield new insights into the genetic and biological basis of hypertension and are fundamental for further studies to explore the intervention strategies targeting L3MBTL4 and p38/JNK to counteract the progression of hypertension.

Glossogyne tenuifolia Attenuates Proliferation and Migration of Vascular Smooth Muscle Cells

The proliferation and migration of vascular smooth muscle cells (VSMCs) are essential in the pathogenesis of various vascular diseases, such as atherosclerosis and restenosis. Among the mediators of VSMC during atherosclerosis development, platelet-derived growth factor (PDGF)-BB is a potent mitogen for VSMCs and greatly contributes to the intimal accumulation of VSMCs. Glossogyne tenuifolia (GT, Xiang-Ru) is a traditional antipyretic and hepatoprotective herb from Penghu Island, Taiwan. This study evaluated the inhibitory effect of GT ethanol extract (GTE) and GT water extract (GTW) on proliferative and migratory activities in PDGF-BB-induced VSMCs. The experimental results demonstrated that GTE significantly inhibited the PDGF-BB-stimulated VSMC proliferation and migration, as shown by MTT, wound healing, and Boyden chamber assays. GTE was found to have a much more potent inhibitory activity than GTW. Based on the Western blot analysis, GTE significantly blocked the PDGF-BB-induced phosphorylation of NF-κB and mitogen-activated protein kinase (MAPK) pathways, including extracellular signal-regulated kinase (ERK), p38, and JNK, in VSMCs. In addition, GTE retarded the PDGF-BB-mediated migration through the suppression of matrix metalloproteinase (MMP)-2 and MMP-9 expression in VSMCs. Three main ingredients of GT-chlorogenic acid, luteolin-7-glucoside, and luteolin-all showed significant anti-proliferative effects on PDGF-BB-induced VSMCs. As a whole, our findings indicated that GTE has the potential to be a therapeutic agent to prevent or treat restenosis or atherosclerosis.

Reactive Oxygen Species: Modulators of Phenotypic Switch of Vascular Smooth Muscle Cells

Reactive oxygen species (ROS) are natural byproducts of oxygen metabolism in the cell. At physiological levels, they play a vital role in cell signaling. However, high ROS levels cause oxidative stress, which is implicated in cardiovascular diseases (CVD) such as atherosclerosis, hypertension, and restenosis after angioplasty. Despite the great amount of research conducted to identify the role of ROS in CVD, the image is still far from being complete. A common event in CVD pathophysiology is the switch of vascular smooth muscle cells (VSMCs) from a contractile to a synthetic phenotype. Interestingly, oxidative stress is a major contributor to this phenotypic switch. In this review, we focus on the effect of ROS on the hallmarks of VSMC phenotypic switch, particularly proliferation and migration. In addition, we speculate on the underlying molecular mechanisms of these cellular events. Along these lines, the impact of ROS on the expression of contractile markers of VSMCs is discussed in depth. We conclude by commenting on the efficiency of antioxidants as CVD therapies.

Spinal heat shock protein 27 participates in PDGFRβ-mediated morphine tolerance through PI3K/Akt and p38 MAPK signalling pathways

BACKGROUND AND PURPOSE

The development of antinociceptive morphine tolerance is a clinically intractable problem. Earlier work has demonstrated the pivotal roles of PDGF and its receptor PDGFRβ in morphine tolerance. Here, we have investigated the role of spinal heat shock protein 27 (HSP27) in morphine tolerance and its relationship with PDGFRβ activation.

EXPERIMENTAL APPROACH

Rats were treated with morphine for 9 days, and its anti-nociceptive effect against thermal pain was evaluated by a tail-flick latency test. Western blot, real-time PCR, immunofluorescent staining, and various antagonists, agonists, and siRNA lentiviral vectors elucidated the roles of HSP27, PDGFRβ, and related signalling pathways in morphine tolerance.

KEY RESULTS

Chronic morphine administration increased expression and phosphorylation of HSP27 in the spinal cord. Down-regulating HSP27 attenuated the development of morphine tolerance. PDGFRβ antagonism inhibited HSP27 activation and attenuated and reversed morphine tolerance. PDGFRβ induction increased HSP27 expression and activation and partly decreased morphine analgesia. PDGFRβ inhibition reduced Akt and p38 MAPK activity in morphine tolerance. PI3K and p38 inhibitors reversed morphine tolerance and suppressed morphine-induced HSP27 phosphorylation.

CONCLUSION AND IMPLICATIONS

This study demonstrated for the first time that spinal HSP27 participates in PDGFRβ-mediated morphine tolerance via the PI3K/Akt and p38 MAPK signalling pathways. These findings suggest a potential clinical strategy for prolonging the antinociceptive effects of opioids during long-term pain control.

Carnosine Impedes PDGF-Stimulated Proliferation and Migration of Vascular Smooth Muscle Cells In Vitro and Sprout Outgrowth Ex Vivo

Carnosine, a naturally producing dipeptide, exhibits various beneficial effects. However, the possible role of carnosine in vascular disorders associated with pathological conditions, including proliferation and migration of vascular smooth muscle cells (VSMCs), largely remains unrevealed. Here, we investigated the regulatory role and mechanism of carnosine in platelet-derived growth factor (PDGF)-induced VSMCs. Carnosine inhibited the proliferation of PDGF-induced VSMCs without any cytotoxic effects. Carnosine treatment also induced G1-phase cell cycle arrest by causing a p21WAF1-mediated reduction in the expression of both cyclin-dependent kinases (CDKs) and cyclins in PDGF-treated VSMCs. Carnosine treatment suppressed c-Jun N-terminal kinase (JNK) phosphorylation in PDGF-stimulated signaling. Additionally, carnosine significantly prevented the migration of VSMCs exposed to PDGF. Carnosine abolished matrix metalloproteinase (MMP)-9 activity via reduced transcriptional binding activity of NF-κB, Sp-1, and AP-1 motifs in PDGF-treated VSMCs. Moreover, using aortic assay ex vivo, it was observed that carnosine addition attenuated PDGF-stimulated sprout outgrowth of VSMCs. Taken together, these results demonstrated that carnosine impeded the proliferation and migration of PDGF-stimulated VSMCs by regulating cell cycle machinery, JNK signaling, and transcription factor-mediated MMP-9 activity as well as prevented ex vivo sprout outgrowth of blood vessels. Thus, carnosine may be a potential candidate for preventing vascular proliferative disease.

The Interaction Between Spinal PDGFRβ and μ Opioid Receptor in the Activation of Microglia in Morphine-Tolerant Rats

Purpose

Opioid tolerance remains a challenging problem, which limits prolonged drug usage in clinics. Previous studies have shown a fundamental role of platelet-derived growth factor receptor β submit (PDGFRβ) in morphine tolerance. The aim of this study was to investigate the mechanisms of spinal PDGFRβ activation in morphine tolerance.

Methods

Rats were treated with morphine for 7 days and the effect of drug was evaluated by tail-flick latency test. By using Western blot and real-time PCR, the interaction between μ opioid receptor (MOR) and PDGFRβ in microglia activation, as well as related signaling pathways during morphine tolerance were investigated.

Results

Chronic PDGFRβ agonist could induce microglia activation in spinal cord and decrease the analgesic effect of morphine. PDGFRβ inhibitor suppressed microglia activation during the development of morphine tolerance. Furthermore, antagonizing MOR could effectively inhibit the phosphorylations of PDGFRβ and JNK. Blocking PDGFRβ had no influence on JNK signaling, while JNK inhibitor could decrease the phosphorylation of PDGFRβ.

Conclusion

These results provide direct evidence that repeatedly activating MOR by morphine could induce the transactivation of PDGFRβ via JNK MAPK in spinal cord, which leads to microglia activation during the development of morphine tolerance.

Cathelicidin Modulates Vascular Smooth Muscle Cell Phenotypic Switching through ROS/IL-6 Pathway

Vascular smooth muscle cells (VSMC) are stromal cells of the blood vessels and their differentiation is thought to be essential during atherosclerosis. Cathelicidin-related antimicrobial peptides (CRAMP) are suggested to play a role in the development of atherosclerosis. Even so, the relationship of CRAMP and VSMC remains unclear. The present study was to determine whether CRAMP regulates VSMC phenotypic transformation and underlying mechanisms. We demonstrated that CRAMP could reverse platelet-derived growth factor-BB (PDGF-BB)-induced VSMC phenotypic transformation, evidencing by increasing α-smooth muscle actin (α-SMA), smooth muscle 22α (SM22α) and decreasing of proliferation and migration. Further studies showed that CRAMP inhibited nuclear factor κB (NF-κB)-induced autocrine of interleukin-6 (IL-6), which further activated of janus kinase 2 (JAK2)/signal transducer and activator 3 (STAT3). Meanwhile, our data showed that CRAMP can significantly inhibit PDGF-BB enhanced intracellular reactive oxygen species (ROS) level which further affected the NF-κB signaling pathway, indicating that CRAMP can regulate the phenotypic transformation of VSMC by regulating oxidative stress. These results indicated that CRAMP regulated the differentiation of VSMC by inhibiting ROS-mediated IL-6 autocrine, suggesting that targeting CRAMP is a potential avenue for regulating the differentiation of VSMC and treatment of atherosclerosis.

Therapeutic approaches to diabetic cardiomyopathy: Targeting the antioxidant pathway

The global epidemic of cardiovascular disease continues unabated and remains the leading cause of death both in the US and worldwide. We hereby summarize the available therapies for diabetes and cardiovascular disease in diabetics. Clearly, the current approaches to diabetic heart disease often target the manifestations and certain mediators but not the specific pathways leading to myocardial injury, remodeling and dysfunction. Better understanding of the molecular events determining the evolution of diabetic cardiomyopathy will provide insight into the development of specific and targeted therapies. Recent studies largely increased our understanding of the role of enhanced inflammatory response, ROS production, as well as the contribution of Cyp-P450-epoxygenase-derived epoxyeicosatrienoic acid (EET), Peroxisome Proliferator-Activated Receptor Gamma Coactivator-1α (PGC-1α), Heme Oxygenase (HO)-1 and 20-HETE in pathophysiology and therapy of cardiovascular disease. PGC-1α increases production of the HO-1 which has a major role in protecting the heart against oxidative stress, microcirculation and mitochondrial dysfunction. This review describes the potential drugs and their downstream targets, PGC-1α and HO-1, as major loci for developing therapeutic approaches beside diet and lifestyle modification for the treatment and prevention of heart disease associated with obesity and diabetes.

Isoliquiritigenin triggers developmental toxicity and oxidative stress-mediated apoptosis in zebrafish embryos/larvae via Nrf2-HO1/JNK-ERK/mitochondrion pathway

Isoliquiritigenin (ISL) is an emerging natural flavonoid found in the roots of licorice, exhibits antioxidant, anti-cancer, anti-inflammatory, anti-allergic, cardioprotective, hepatoprotective and neuroprotective properties. However, the effect of ISL in embryonic development is yet to be elucidated, and the mechanisms underlying its target-organ toxicity and harmful side effects are still unclear. In the present study, we employed zebrafish embryos to study the developmental toxicity effect of ISL and its underlying mechanisms. Zebrafish embryos upon treatment with either vehicle control (0.1% DMSO) or ISL solutions for 4-96 h post fertilization (hpf) showed that ISL exposure instigated severe developmental toxicity in heart, liver, and nervous system. Mortality and morphological abnormalities were also observed. High concentrations of ISL exposure resulted in abnormal phenotypes and embryonic malformations including pericardial edema, swim bladder defects, yolk retention, curved body shape and shortening of body length. Moreover, ISL exposure led to significant loss of dopaminergic neurons accompanied by reduced locomotor behaviour. Apoptotic cells were predominantly located in the heart area of 96 hpf embryo. Additionally, ISL significantly increased the levels of reactive oxygen species, lipid peroxidation content and decreased antioxidant enzyme activities. The expressions pattern of apoptosis-related genes Bad, Cyto c, Caspase-9, Caspase-3 and Bax/Bcl-2 indicated that the oxidative stress-induced apoptosis triggered by ISL suggest involvement of Nrf2-HO1/JNK-ERK/mitochondrion pathways. In conclusion, here we provide first evidence that demonstrate ISL-induced dose-dependent developmental toxicity in zebrafish embryos. Furthermore, gene expression patterns in the embryos correlate the above and reveal potential genetic mechanisms of developmental toxicity.

l-Theanine attenuates neointimal hyperplasia via suppression of vascular smooth muscle cell phenotypic modulation

Neointimal hyperplasia is a prominent pathological phenomenon in the process of stent restenosis. Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) play major pathological processes involved in the development of restenosis. l-Theanine, one of the major amino acid components in green tea, has been reported to improve vascular function. Here we display the effects of l-theanine on neointima formation and the underlying mechanism. In the rat carotid-artery balloon-injury model, l-theanine greatly inhibited neointima formation and prevented VSMCs from a contractile phenotype switching to a synthetic phenotype. In vitro study showed that l-theanine significantly inhibited PDGF-BB-induced VSMC proliferation and migration, which was comparable with the effect of l-theanine on AngII-induced VSMC proliferation and migration. Western blot analysis demonstrated that l-theanine suppressed PDGF-BB and AngII-induced reduction of SMA and SM22α and increment of OPN, suggesting that l-theanine inhibited the transformation of VSMCs from contractile to the synthetic phenotype. Further experiments showed that l-theanine exhibits potential preventive effects on neointimal hyperplasia and related vascular remodeling via inhibition of phosphorylation of Elk-1 and activation of MAPK1. The present study provides the new experimental evidence that l-theanine has potential clinical application as an anti-restenosis agent for the prevention of restenosis.

Deletion of the FHL2 gene attenuates intima-media thickening in a partially ligated carotid artery ligated mouse model

The four and a half LIM domain protein 2 (FHL2) is a member of the four and a half LIM domain (FHL) gene family, and it is associated with cholesterol‐enriched diet‐promoted atherosclerosis. However, the effect of FHL2 protein on vascular remodelling in response to hemodynamic alterations remains unclear. Here, we investigated the role of FHL2 in a model of restricted blood flow‐induced atherosclerosis. To promote neointimal hyperplasia in vivo, we subjected FHL2^+/+ and FHL2^−/− mice to partial ligation of the left carotid artery (LCA). The expression of p‐ERK and p‐AKT was decreased in FHL2^−/− mice. FHL2 bound to AKT regulated AKT phosphorylation and led to Rac1‐GTP inactivation. FHL2 silencing in human aortic smooth muscle cells down‐regulated the PDGF‐induced phosphorylation of ERK and AKT. Furthermore, FHL2 silencing reduced cytoskeleton conformational changes and caused cell cycle arrest. We concluded that FHL2 is essential for the regulation of arterial smooth muscle cell function. FHL2 modulates proliferation and migration via mitogen‐activated protein kinase (MAPK) and PI3K‐AKT signalling, leading to arterial wall thickening and thus neointimal hyperplasia.

miR-21 regulates vascular smooth muscle cell function in arteriosclerosis obliterans of lower extremities through AKT and ERK1/2 pathways

INTRODUCTION

Arteriosclerosis obliterans (ASO) is a disease that affects the lower extremities. The mechanism of ASO is associated with the proliferation and migration of vascular smooth muscle cells (VSMCs). miR-21 plays a key role in various biological processes of the cardiovascular system, associated with the proliferation, migration and apoptosis of VSMCs. It is unclear, however, if miR-21 is involved in the regulation of ASO.

MATERIAL AND METHODS

Human aortic smooth muscle cells (HASMCs) were transfected with miR-21 mimics and co-treated with protein kinase B (AKT) or a mitogen-activated protein kinase (ERK) inhibitor. Expression levels of p-AKT or p-ERK were measured by western blot. Cell apoptosis was assessed using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and visualized under a fluorescence microscope. Cell proliferation was monitored by bromodeoxyuridine (BrdU) labeling; cell migration and invasion were determined by the Transwell assay.

RESULTS

miR-21 was upregulated in arteries of ASO, the pathogenesis of which involved the activation of p-AKT and p-ERK1/2. Inhibition of the AKT or ERK activity was consistent with the attenuation of the miR-21-induced HASMC migration and proliferation. HASMCs co-treated with miR-21 mimics and AKT or ERK inhibitor showed attenuation of the miR-21-induced high elongation ratio.

CONCLUSIONS

We demonstrated that the expression of miR-21 in HASMCs could find potential application in cardiac therapy. Inhibition of the activity of AKT or ERK could attenuate miR-21-induced cell proliferation and migration as well as altering morphology of HASMCs. The present study aimed to indicate the potential roles of miR-21 in ASO processes, and the results provided a novel therapeutic approach for treating ASO and new targets for preventing ASO in earlier stages.

HO-1 overexpression and underexpression: Clinical implications

In this review we examine the effects of both over- and under-production of heme oxygenase-1 (HO-1) and HO activity on a broad spectrum of biological systems and on vascular disease. In a few instances e.g., neonatal jaundice, overproduction of HO-1 and increased HO activity results in elevated levels of bilirubin requiring clinical intervention with inhibitors of HO activity. In contrast HO-1 levels and HO activity are low in obesity and the HO system responds to mitigate the deleterious effects of oxidative stress through increased levels of bilirubin (anti-inflammatory) and CO (anti-apoptotic) and decreased levels of heme (pro-oxidant). Site specific HO-1 overexpression diminishes adipocyte terminal differentiation and lipid accumulation of obesity mediated release of inflammatory molecules. A series of diverse strategies have been implemented that focus on increasing HO-1 and HO activity that are central to reversing the clinical complications associated with diseases including, obesity, metabolic syndrome and vascular disease.

COL6A1 knockdown suppresses cell proliferation and migration in human aortic vascular smooth muscle cells

Vascular smooth muscle cell (VSMC) migration is an important pathophysiological signature of neointimal hyperplasia. The aim of the present study was to investigate the effects of collagen type VI α1 chain (COL6A1) on VSMC migration. COL6A1 expression was silenced in platelet-derived growth factor (PDGF-BB)-stimulated VSMCs. Cell counting kit-8, wound healing and Transwell assays were used to measure cell viability, migration and invasion, respectively. Reverse transcription-quantitative PCR and western blot analysis were performed to analyze the expression of factors associated with metastasis. COL6A1 silencing attenuated PDGF-BB-induced increases in cell viability and invasive abilities of VSMCs, in addition to partially reversing the increased expression of fibronectin (FN), matrix metalloproteinase (MMP)-2 and MMP-9 induced by PDGF-BB stimulation. The silencing of COL6A also overturned PDGF-BB-induced reduction in tissue inhibitor of metalloproteinase 2 expression in VSMCs. PDGF-BB activated the AKT/mTOR pathway, which was also inhibited by COL6A1 knockdown. Taken together, these findings suggest that COL6A1 silencing inhibited VSMC viability and migration by inhibiting AKT/mTOR activation.

Inhibitory effects of scoparone from chestnut inner shell on platelet-derived growth factor-BB-induced vascular smooth muscle cell migration and vascular neointima hyperplasia

BACKGROUND

Compounds of the inner shell of chestnut (Castanea crenata) have diverse biological activities, including anti-cancer and anti-oxidant activities. Here we explored the effects of an extract of chestnut inner shells and of its bioactive component scoparone on vascular smooth muscle cell migration and vessel damage.

RESULTS

The ethanol extract of chestnut inner shells, containing 11 major compounds, inhibited platelet-derived growth factor (PDGF)-BB-induced migration of rat aortic smooth muscle cells (RASMCs). Among these compounds, scoparone (6,7-dimethoxycoumarin) suppressed RASMC migration and wound healing in response to PDGF-BB but did not affect RASMC proliferation. In RASMCs, scoparone inhibited the PDGF-BB-induced rat aortic sprout outgrowth and attenuated the PDGF-BB-mediated increase in phosphorylation of mitogen-activated protein kinases (MAPKs), p38 MAPK and extracellular signal-regulated kinase 1/2. The in vivo administration of scoparone resulted in the attenuation of neointima formation in balloon-injured carotid arteries of rats.

CONCLUSION

These findings demonstrate that scoparone, found in chestnut inner shells, may inhibit cell migration through suppression of the phosphorylation of MAPKs in PDGF-BB-treated RASMCs, probably contributing to the reduction of neointimal hyperplasia induced after vascular injury. Therefore, scoparone and chestnut inner shell may be a potential agent or functional food, respectively, for the prevention of vascular disorders such as vascular restenosis or atherosclerosis. © 2019 Society of Chemical Industry.

Comprehensive transcriptomic view of the role of the LGALS12 gene in porcine subcutaneous and intramuscular adipocytes

Background

Livestock production aims to provide meats of high and consistent eating quality. Insufficient intramuscular (IM) fat and excessive subcutaneous (SC) fat are paramount pork quality challenges. IM fat and SC fat, which are modulated by the adipogenesis of IM and SC adipocytes, play key roles in pork quality. Galectin-12 (LGALS12) was proven to be an important regulator of fat deposition in porcine. However, the current knowledge of the transcriptome-wide role of LGALS12 in adipocytes is still limited. This study was aimed to discover the different regulatory mechanisms of LGALS12 in porcine IM and SC adipocyte.

Results

The siRNA-mediated knockdown of the expression of LGALS12 identified 1075 and 3016 differentially expressed genes (DEGs) in IM and SC adipocytes, respectively. Among these, 585 were up- and 490 were downregulated in the IM adipocytes, while 2186 were up- and 830 were downregulated in the SC adipocytes. Moreover, 418 DGEs were observed only in the IM adipocytes, 2359 DGEs only in the SC adipocytes, and 657 DGEs in both types of adipocytes. According to Gene Ontology (GO) analysis, DEGs in both IM and SC adipocytes were mainly enriched in categories related to lipids or fat cell differentiation. Pathway analysis of the DEGs revealed 88 changed signaling pathways in the IM adipocytes and 86 in the SC adipocytes. The signaling pathways present in only one type of adipocyte were identified from among the top 50 signaling pathways in each type of adipocyte. Four signaling pathways, encompassing PI3K-AKT, cardiac muscle contraction, fatty acid metabolism and Ras, were significantly enriched in the IM adipocytes. On the other hand, four different signaling pathways, encompassing TNF, WNT, cGMP-PKG and NF-kappa B, were greatly enriched in the SC ones. The pathway changes were confirmed by chemical inhibition assays.

Conclusions

Our data reveals that LGALS12 knockdown alters the expression of numerous genes involved in key biological processes in the development of adipocytes. These observations provide a global view of the role of LGALS12 in porcine IM and SC adipocytes; thus, improving our understanding of the regulatory mechanisms by which this gene acts in fat development.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5891-y) contains supplementary material, which is available to authorized users.

Cocaine addicted to cytoskeletal change and a fibrosis high

Cocaine is one of the most widely abused illicit drugs due to its euphoric and addictive properties. Cocaine-mediated cognitive impairments are the result of dynamic cytoskeletal rearrangements involved in mediating structural and behavioural plasticity. Cytoskeletal changes initiated following cocaine abuse are regulated by the Rho family of GTPases with significant downstream activity in key actin binding proteins. Moreover, signalling via the endoplasmic reticulum chaperone protein, sigma-1 receptor has highlighted the possibility of cocaine regulated pathology in other organ systems. However, the question of whether upstream stimulation of such a high affinity binding receptor is directly involved in cocaine-mediated cytoskeletal changes at present remains unknown. In this review, we describe the functional role of key cytoskeletal regulators in response to cocaine-induced signalling cues. In addition, we ascertain the extent of whether global cytoskeletal modulators involved in cocaine-induced neurological stimulation can be used as a platform for future studies into elucidating its fibrotic potential within the hepatic microenvironment. A focus on aspects still poorly understood relating to the nonneuronal pathological impact of cocaine is discussed in the sphere of hepatic dysregulation. Lastly, we suggest that cocaine may mediate its pathological capacity via the sigma1 receptor in regulating hepatoxicity, hepatic stellate cells activity, cytoskeletal dynamics, and the transcriptional regulation of key hepato-fibrogenic modulators.

A “self-accelerating endosomal escape” siRNA delivery nanosystem for significantly suppressing hyperplasia via blocking the ERK2 pathway

Highly efficient ERK2 silencing in VSMCs via a “self-accelerating endosomal escape” siRNA transport nanosystem.

Expression of a Functional IL-2 Receptor in Vascular Smooth Muscle Cells

Many nonlymphoid cell types express at least two, if not all three, subunits of the IL-2R; although, compared with lymphocytes, relatively little is known about how IL-2 affects the function of nonlymphoid cells. The limited information available suggests that IL-2 has a substantial impact on cells such as gastrointestinal epithelial cells, endothelial cells, and fibroblasts. In a previous report from our laboratory, we noted that IL-2 and IL-2Rβ-deficient mice lose smooth muscle cells over time, eventually resulting in aneurysmal aortas and ectatic esophagi. This finding, combined with our work showing that IL-2 surrounds vascular smooth muscle cells by association with perlecan, led us to ask whether vascular smooth muscle cells express an IL-2R. Toward this end, we reported the expression of IL-2Rβ on human and murine vascular smooth muscle cells. We now report that vascular smooth muscle cells express all three subunits of the IL-2R, and that expression of IL-2Rα varies with vascular smooth muscle cell phenotype. Furthermore, we show that, through a functional IL-2R, IL-2 initiates signaling pathways and impacts vascular smooth muscle cell function. Finally, we demonstrate that IL-2 expression increases upon initiation of conditions that promote intimal hyperplasia, suggesting a mechanism by which the IL-2/IL-2R system may impact this widespread vascular pathology.

Behavioral remodeling of normal and cancerous epithelial cell lines with differing invasion potential induced by substrate elastic modulus

The micro-environment of cancer cells in the body is mechanically stiffer than that of normal cells. We cultured three breast cell lines of MCF10A-normal, MCF7-noninvasive, and MDA-MB-231-invasive on PDMS substrates with different elastic moduli and different cellular features were examined.Effects of substrate stiffness on cell behavior were evident among all cell lines. Cancerous cells were more sensitive to substrate stiffness for cell behaviors related to cell motility and migration which are necessary for invasion. The invasive cancerous cells were the most motile on substrates with moderate stiffness followed by non-invasive cancerous cells. Gene markers alterations were generally according to the analyzed cell movement parameters. Results suggest that alterations in matrix stiffness may be related to cancer disease and progression.

PDGF Restores the Defective Phenotype of Adipose-Derived Mesenchymal Stromal Cells from Diabetic Patients

Diabetes is a chronic metabolic disorder that affects 415 million people worldwide. This pathology is often associated with long-term complications, such as critical limb ischemia (CLI), which increases the risk of limb loss and mortality. Mesenchymal stromal cells (MSCs) represent a promising option for the treatment of diabetes complications. Although MSCs are widely used in autologous cell-based therapy, their effects may be influenced by the constant crosstalk between the graft and the host, which could affect the MSC fate potential. In this context, we previously reported that MSCs derived from diabetic patients with CLI have a defective phenotype that manifests as reduced fibrinolytic activity, thereby enhancing the thrombotic risk and compromising patient safety. Here, we found that MSCs derived from diabetic patients with CLI not only exhibit a prothrombotic profile but also have altered multi-differentiation potential, reduced proliferation, and inhibited migration and homing to sites of inflammation. We further demonstrated that this aberrant cell phenotype is reversed by the platelet-derived growth factor (PDGF) BB, indicating that PDGF signaling is a key regulator of MSC functionality. These findings provide an attractive approach to improve the therapeutic efficacy of MSCs in autologous therapy for diabetic patients.

Semaphorin-3E attenuates neointimal formation via suppressing VSMCs migration and proliferation

Aims

The migration and proliferation of vascular smooth muscle cells (VSMCs) are crucial events in the neointimal formation, a hallmark of atherosclerosis and restenosis. Semaphorin3E (Sema3E) has been found to be a critical regulator of cell migration and proliferation in many scenarios. However, its role on VSMCs migration and proliferation is unclear. This study aimed to investigate the effect of Sema3E on VSMCs migration, proliferation and neointimal formation, and explore possible mechanisms.

Methods and results

We found that the expression of Sema3E was progressively decreased during neointimal formation in a carotid ligation model. H&E-staining showed lentivirus-mediated overexpression of Sema3E in carotid ligation area attenuated neointimal formation. Immunofluorescence staining showed that the receptor (PlexinD1) of Sema3E was expressed in vascular walls. In cultured mouse VSMCs, Sema3E inhibited VSMCs migration and proliferation via plexinD1 receptor. The inhibitory effect was mediated, at least in part, by inactivating Rap1-AKT signalling pathways in VSMCs. Moreover, we found that PDGFBB down-regulated the expression of Sema3E in VSMCs and Sema3E notably inhibited the expression of PDGFB in endothelial cells. In addition, the number of Sema3E-positive VSMCs was diminished in plaques of atherosclerotic patients. Results from a public GEO microarray database showed a negative correlation between Sema3E and PDGFB transcriptional levels in the human plaques examined.

Conclusion

Our study demonstrates that Sema3E/plexinD1 inhibits proliferation and migration of VSMCs via inactivation of Rap1-AKT signalling pathways. The mutual inhibition between PDGF-BB and Sema3E after vascular injury plays a critical role in the process of neointimal formation.