Vascular Smooth Muscle Cells Phenotypic Switching in Cardiovascular Diseases

Nec-1 regulates phenotypic transformation of heat stroke-induced vascular smooth muscle cells by inhibiting RIPK1

OBJECTIVE

Cardiovascular injury is a common complication of heat stroke (HS). However, the mechanism underlying vascular smooth muscle cells (VSMCs) following HS remains unclear.

METHOD

A rat and VSMCs model was established by simulating high-temperature exposure. Primary VSMC was extracted in vitro, and CCK8 screened the concentration of Nec-1 and detected cell proliferation activity. The expression of α-smooth muscle protein (α-SMA), osteopontin (OPN), receptor-interacting protein kinase 1 (RIPK1), receptor-interacting protein kinase 3 (RIPK3), Bcl-2 and Bax were detected by immunohistochemistry and Western blot.

RESULTS

The results of in vivo experiments showed that with the prolongation of HS recovery time, α-SMA expression basically decreased and OPN expression increased. Meanwhile, the expression of RIPK1 and RIPK3 was increased, which promoted the occurrence of necroptosis. In vitro results showed that with the extension of HS recovery time, the proliferative viability of VSMCs decreased, the cell morphology changed, and the apoptotic cells increased. The fluorescence results indicate that the expression levels of RIPK1 and PIPK3 in the cells are elevated, accompanied by the typical characteristics of cell necroptosis. Nec-1 restored the decreased cell viability and the high expression of RIPK1 and RIPK3 induced by heat stroke, and improved the occurrence of cell necrotic apoptosis. Nec-1 also restored α-SMA expression, reduced OPN expression, and reversed phenotypic abnormalities of VSMC caused by heat stroke.

CONCLUSION

HS induces abnormal phenotypic transformation and necroptosis in VSMCs. Necrostatin-1 can improve necroptosis and maintain the contractile phenotype of VSMCs. This study can provide new insights into cardiovascular damage caused by high temperatures.

TRPC6-Mediated Zn2+ Influx Negatively Regulates Contractile Differentiation of Vascular Smooth Muscle Cells

Vascular smooth muscle cells (VSMCs) can dynamically change their phenotype between contractile and synthetic forms in response to environmental stress, which is pivotal in maintaining vascular homeostasis and mediating pathological remodeling of blood vessels. We previously reported that suppression of canonical transient receptor potential 6 (TRPC6) channel-mediated cation entry sustains VSMCs contractile phenotype and promotes the blood flow recovery after hindlimb ischemia in mice. We also reported that Zn2+, a metal biomolecule mobilized by TRPC6 channel activation, exerts potential beneficial effects on cardiac contractility and remodeling. Therefore, we hypothesized that TRPC6-mediated Zn2+ influx participates in phenotype switching of VSMCs and vascular remodeling. We established rat aortic smooth muscle cells (RAoSMCs) stably expressing wild type (WT) and Zn2+ only impermeable TRPC6 (KYD) mutant. Although the resting phenotypes were similar in both RAoSMCs, pharmacological TRPC6 activation by PPZ2 prevented the transforming growth factor (TGF) β-induced reduction in the intracellular Zn2+ amount and contractile differentiation in RAoSMCs (WT), but failed to prevent them in RAoSMCs (KYD). There were no significant differences in TRPC6-dependent cation currents among all RAoSMCs pretreated with or without TGFβ and/or PPZ2, suggesting that TRPC6 channels are functionally expressed in RAoSMCs regardless of their phenotype. Treatment of mice with PPZ2 attenuated the progression of vascular remodeling caused by chronic angiotensin II infusion. These results suggest that Zn2+ influx through TRPC6 channels negatively regulates the TGFβ-induced contractile differentiation of VSMCs and the progression of vascular remodeling in rodents.

The Emerging Role of m6A and Programmed Cell Death in Cardiovascular Diseases

N6-methyladenosine (m6A) is the most prevalent internal chemical modification in eukaryotic messenger RNA (mRNA), significantly impacting its lifecycle through dynamic and reversible processes involving methyltransferase, demethylase, and binding proteins. These processes regulate mRNA stability, splicing, nuclear export, translation, and degradation. Programmed cell death (PCD), a tightly controlled process encompassing apoptosis, pyroptosis, ferroptosis, autophagy, and necroptosis, plays a crucial role in maintaining cellular homeostasis, tissue development, and function. Recently, m6A modification has emerged as a significant research area due to its role in regulating PCD and its implications in cardiovascular diseases (CVDs). In this review, we delve into the intricate relationship between various PCD types and m6A modification, emphasizing their pivotal roles in the initiation and progression of CVDs such as myocardial ischemia-reperfusion (I/R), atherosclerosis (AS), pulmonary hypertension (PH), cardiomyopathy, doxorubicin (Dox)-induced cardiotoxicity (DIC), heart failure (HF), and myocardial infarction (MI). Our findings underscore the potential of elucidating the roles of m6A and PCD in CVD to pave new pathways for prevention and treatment strategies.

Fibrinopeptide a promotes the proliferation and migration of vascular smooth muscle cells by regulating the integrin αVβ3/PI3K/AKT signaling pathway

BACKGROUND

Atherosclerosis is characterized by subintimal proliferation and migration of vascular smooth muscle cells (VSMCs) in response to stimuli such as coagulation and inflammatory factors. Fibrinopeptide A (FPA), a biomarker for coagulation system activation, is elevated in patients with ischemic heart disease. However, its role in the pathophysiology of cardiovascular disorders remains unclear. This study aimed to investigate the impact of FPA on VSMCs proliferation and migration and elucidate the underlying molecular mechanisms.

METHODS AND RESULTS

Transcriptome sequencing and bioinformatics analysis were employed to elucidate molecular pathways. Scratch wound and Transwell assays were performed to evaluate cell migration capacity. Molecular expression patterns were assessed using immunofluorescence, real-time quantitative PCR, and Western blot assays. The differentially expressed genes (DEGs) in the FPA-treated VSMCs were enriched in the cell cycle and PI3K/AKT signaling pathway. FPA treatment enhanced VSMCs' migratory capacity and upregulated integrin αVβ3, PI3K, P-AKT, AKT, Cyclin D1, and PCNA expression. The integrin αVβ3 inhibitor Cyclo-RGDfk effectively suppressed VSMCs migration and reduced the expression levels of these genes in FPA-stimulated VSMCs.

CONCLUSIONS

These results suggested that FPA promotes the proliferation and migration of VSMCs by regulating the PI3K/AKT signaling pathway through integrin αVβ3.

Virgin and photo-degraded microplastics induce the activation of human vascular smooth muscle cells

Microplastics (MPs) are an emerging environmental issue due to their accumulation in ecosystems and living organisms. Increasing evidence shows that MPs impact vascular function, with recent studies finding MPs in atheromas linked to cardiovascular events. Since vascular smooth muscle cells (VSMCs) are crucial to maintaining vascular function, this study examined how MPs activate VSMCs, leading to cardiovascular diseases like atherosclerosis and vascular calcification. The study used polyethylene (PE) and polystyrene (PS), common in food packaging, as "virgin" or photo-degraded to simulate environmental conditions. VSMC viability, apoptosis, cytotoxicity, inflammation, and activation markers were evaluated. PE and PS affected VSMC viability, induced apoptosis, and triggered pathological changes such as altered migration and proliferation. Key markers like RUNX-2 and galectin-3, which regulate cardiovascular pathology, were activated, alongside the inflammasome complex. In conclusion, MPs can induce harmful activation of VSMCs, posing potential health risks through inflammation, cell damage, and phenotypic changes. Understanding these toxic mechanisms may reveal critical pathways for intervention and prevention.

Role of C/EBP Homologous Protein in Vascular Stenosis After Carotid Artery Injury

The study aims to explore the fluctuating expression of C/EBP Homologous Protein (CHOP) following rat carotid artery injury and its central role in vascular stenosis. Using in vivo rat carotid artery injury models and in vitro ischemia and hypoxia cell models employing human aortic endothelial cells (HAECs) and vascular smooth muscle cells (T/G HA-VSMCs), a comprehensive investigative framework was established. Histological analysis confirmed intimal hyperplasia in rat models. CHOP expression in vascular tissues was assessed using Western blot and immunohistochemical staining, and its presence in HAECs and T/G HA-VSMCs was determined through RT-PCR and Western blot. The study evaluated HAEC apoptosis, inflammatory cytokine secretion, cell proliferation, and T/G HA-VSMCs migration through Western blot, ELISA, CCK8, and Transwell migration assays. The rat carotid artery injury model revealed substantial fibrous plaque formation and vascular stenosis, resulting in an increased intimal area and plaque-to-lumen area ratio. Notably, CHOP is markedly elevated in vessels of the carotid artery injury model compared to normal vessels. Atorvastatin effectively mitigated vascular stenosis and suppresses CHOP protein expression. In HAECs, ischemia and hypoxia-induced CHOP upregulation, along with heightened TNFα, IL-6, caspase3, and caspase8 levels, while reducing cell proliferation. Atorvastatin demonstrated a dose-dependent suppression of CHOP expression in HAECs. Downregulation of CHOP or atorvastatin treatment led to reduced IL-6 and TNFα secretion, coupled with augmented cell proliferation. Similarly, ischemia and hypoxia conditions increased CHOP expression in T/G HA-VSMCs, which was concentration-dependently inhibited by atorvastatin. Furthermore, significantly increased MMP-9 and MMP-2 concentrations in the cell culture supernatant correlated with enhanced T/G HA-VSMCs migration. However, interventions targeting CHOP downregulation and atorvastatin usage curtailed MMP-9 and MMP-2 secretion and suppressed cell migration. In conclusion, CHOP plays a crucial role in endothelial injury, proliferation, and VSMCs migration during carotid artery injury, serving as a pivotal regulator in post-injury fibrous plaque formation and vascular remodeling. Statins emerge as protectors of endothelial cells, restraining VSMCs migration by modulating CHOP expression.

Intravascular delivery of an MK2 inhibitory peptide to prevent restenosis after angioplasty

Peripheral artery disease is commonly treated with balloon angioplasty, a procedure involving minimally invasive, transluminal insertion of a catheter to the site of stenosis, where a balloon is inflated to open the blockage, restoring blood flow. However, peripheral angioplasty has a high rate of restenosis, limiting long-term patency. Therefore, angioplasty is sometimes paired with delivery of cytotoxic drugs like paclitaxel to reduce neointimal tissue formation. We pursue intravascular drug delivery strategies that target the underlying cause of restenosis - intimal hyperplasia resulting from stress-induced vascular smooth muscle cell switching from the healthy contractile into a pathological synthetic phenotype. We have established MAPKAP kinase 2 (MK2) as a driver of this phenotype switch and seek to establish convective and contact transfer (coated balloon) methods for MK2 inhibitory peptide delivery to sites of angioplasty. Using a flow loop bioreactor, we showed MK2 inhibition in ex vivo arteries suppresses smooth muscle cell phenotype switching while preserving vessel contractility. A rat carotid artery balloon injury model demonstrated inhibition of intimal hyperplasia following MK2i coated balloon treatment in vivo. These studies establish both convective and drug coated balloon strategies as promising approaches for intravascular delivery of MK2 inhibitory formulations to improve efficacy of balloon angioplasty.

Modulating vascular smooth muscle cell phenotype via Wnt-Independent FRZB pathways

BACKGROUND AND AIMS

Vascular smooth muscle cells are pivotal in atherosclerosis, transitioning from a contractile to a synthetic phenotype, which is associated with increased proliferation and inflammation. FRZB, a Wnt signaling modulator, has been implicated in vascular pathology, but its specific role in vascular smooth muscle cell phenotype modulation is not well understood. This study investigates the role of FRZB in regulating vascular smooth muscle cell phenotypes.

METHODS

Vascular smooth muscle cell regions were categorized based on FRZB expression levels, and various analyses, including differential gene expression, KEGG pathway analysis, and Disease Ontology analysis, were conducted. FRZB knockdown in human aortic vascular smooth muscle cell was performed using siRNA, followed by assessments of cell migration, proliferation, and phenotype marker expression.

RESULTS

FRZB expression was significantly reduced in synthetic type compared to contractile type in both mouse models and human samples. FRZB knockdown in human vascular smooth muscle cells led to increased cell migration and proliferation, alongside decreased expression of contractile markers and increased synthetic markers. Unexpectedly, FRZB knockdown suppressed Wnt signaling. Pathway analysis revealed associations with the PI3K-Akt signaling pathway, focal adhesion, and ECM interactions.

CONCLUSIONS

Our study highlights FRZB's role in Vascular smooth muscle cell phenotype modulation, showing that reduced FRZB expression correlates with a synthetic phenotype and increased disease markers. FRZB does not enhance Wnt signaling but may regulate vascular smooth muscle cell behavior through alternative pathways. These findings suggest FRZB as a potential therapeutic target for stabilizing vascular smooth muscle cells and managing atherosclerosis.

Degraded products generated by iron stent inhibit the vascular smooth muscle cell proliferation by downregulating AP-1

In-stent restenosis (ISR) following interventional therapy is a fatal clinical complication. Current evidence indicates that neointimal hyperplasia driven by uncontrolled proliferation of vascular smooth muscle cells (VSMC) is a major cause of restenosis. This implies that inhibiting VSMC proliferation may be an attractive approach for preventing in-stent restenosis. In our previous study, we found that the iron stent reduced the neointimal hyperplasia in an atherosclerotic artery stenosis model, and the iron corroded granules generated by the iron stent inhibited neointimal hyperplasia by suppressing the proliferation of VSMCs. However, this observation needs to be validated through in vitro experimentation. In this study, co-culture experiments and flow cytometer assays were performed to qualitatively investigate the effects of iron stent degradation on VSMCs. Moreover, the degraded products resulting generated by the iron stent were collected and used to elucidate the suppressive effect of the iron stents. The underlying mechanism was explored through molecular biology assays. The major findings are as follows: 1) The degraded iron stent inhibited the proliferation of VSMCs; 2) The degraded products of the iron stent downregulated the expression of AP-1. In summary, this study demonstrates the inhibitory effect of degraded iron products on VSMC proliferation, implying that such products have the potential to mitigate in-stent restenosis.

Perivascular cells function as key mediators of mechanical and structural changes in vascular capillaries

A hallmark of chronic and inflammatory diseases is the formation of a fibrotic and stiff extracellular matrix (ECM), typically associated with abnormal, leaky microvascular capillaries. Mechanisms explaining how the microvasculature responds to ECM alterations remain unknown. Here, we used a microphysiological model of capillaries on a chip mimicking the characteristics of healthy or fibrotic collagen to test the hypothesis that perivascular cells mediate the response of vascular capillaries to mechanical and structural changes in the human ECM. Capillaries engineered in altered fibrotic collagen had abnormal migration of perivascular cells, reduced pericyte differentiation, increased leakage, and higher regulation of inflammatory/remodeling genes, all regulated via NOTCH3, a known mediator of endothelial-perivascular cell communication. Capillaries engineered either with endothelial cells alone or with perivascular cells silenced for NOTCH3 expression showed a minimal response to ECM alterations. These findings reveal a previously unknown mechanism of vascular response to changes in the ECM in health and disease.

Histone deacetylase 6 inhibition prevents hypercholesterolemia-induced erectile dysfunction independent of changes in markers of autophagy

Background

Erectile dysfunction is a condition with a rapidly increasing prevalence globally with a strong correlation to the increase in obesity and cardiovascular disease rates.

Aim

The aim of the current study is to investigate the potential role of tubacin, a histone deacetylase 6 (HDAC6) inhibitor, in restoring erectile function in a hypercholesterolemia-induced endothelial dysfunction model.

Methods

Thirty-nine male C57Bl/6 J mice were divided into 3 groups. Two groups were administered an adeno-associated virus encoding for the gain of function of proprotein convertase subtilisin/kexin type 9 (PCSK9) and placed on a high-fat diet (HFD) with 1.25% cholesterol added for 18 weeks in order to induce a prolonged state of hypercholesterolemia. One of the PCSK9 groups received daily intraperitoneal injections of the HDAC6 inhibitor tubacin, while the other 2 groups received daily vehicle injections. Erectile function was assessed through measurement of intracavernosal pressure and mean arterial pressure during cavernous nerve stimulation, as well as assessment of agonist-stimulated ex vivo relaxation of the corpus cavernosum (CC). Western blotting was performed from CC tissue samples.

Outcomes

Erectile and endothelial functions were assessed, as well as protein markers of mitochondrial dynamics, mitophagy, and autophagy.

Results

Erectile function was impaired in the HFD + PCSK9 group throughout the entire voltage range of stimulation. However, the HFD + PCSK9 mice that were treated with tubacin experienced significant restoration of erectile function at the medium and high voltages of nerve stimulation. Similarly, ex vivo CC relaxation responses to acetylcholine and the cystathionine γ-lyase (CSE) substrate L-cysteine were reduced in the vehicle-treated HFD + PCSK9 mice, both of which were restored in the HFD + PCSK9 mice treated with tubacin. Corpus-cavernosum protein expression of CSE was significantly elevated in the tubacin-treated HFD + PCSK9 mice relative to both other groups. There were no significant differences observed in any of the protein markers of mitochondrial dynamics, mitophagy, or autophagy investigated.

Clinical translation

Histone deacetylase 6 inhibition may protect against erectile and endothelial dysfunction associated with hypercholesterolemia.

Strengths and limitations

This was the first study to investigate HDAC6-specific inhibition for treatment of erectile dysfunction. A study limitation was the exclusive focus on the CC, rather than structure and function of the pre-penile arteries that may develop a substantial atherosclerotic plaque burden under hypercholesterolemic conditions.

Conclusions

Tubacin may prevent hypercholesterolemia-induced erectile dysfunction through a hydrogen sulfide-related mechanism unrelated to regulation of mitophagy or autophagy.

Single-Cell RNA-Seq Reveals Injuries in Aortic Dissection and Identifies PDGF Signalling Pathway as a Potential Therapeutic Target

Aortic dissection (AD) represents a critical condition characterised by a tear in the inner lining of the aorta, leading to the leakage of blood into the layers of the aortic wall, posing a significant risk to life. However, the pathogenesis is unclear. In this study, scRNA-seq was applied to cells derived from aortas of both AD and non-AD donors (control) to unveil the cellular landscape. ScRNA-seq data uncover significant cellular heterogeneity in AD aortas. Specifically, we observed an accumulation of CD4+ T cells, which contributed to inflammation and cell death, and abnormal collagen formation mediated by fibroblast cells in AD. Moreover, we revealed a greater prevalence of cell death, oxidative stress and senescence in AD aorta cells. Furthermore, we found a decrease in the percentage of vascular stem cells (VSCs), along with a repression in their ability to differentiate into contractile vascular smooth muscle cells (VSMCs). Finally, our data demonstrated that the PDGF signalling pathway was activated in AD. We found that PDGF activation could lead to VSMCs aberrant switch from contractile to synthetic phenotype, which could be ameliorated by PDGF inhibitor. This underscores the potential of the PDGF as a therapeutic target for AD. In summary, our study highlights the cellular heterogeneity and associated injuries within aortas affected by AD, including cell death, oxidative stress, senescence and dysregulation of signalling pathways influencing the aberrant phenotypic switch of VSMCs. These insights offer valuable contributions to understanding the molecular mechanisms underlying AD and present new avenues for therapeutic intervention in this condition.

Phenotypic switch of vascular smooth muscle cells in COVID-19: Role of cholesterol, calcium, and phosphate

Although the novel coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily manifests as severe respiratory distress, its impact on the cardiovascular system is also notable. Studies reveal that COVID-19 patients often suffer from certain vascular diseases, partly attributed to increased proliferation or altered phenotype of vascular smooth muscle cells (VSMCs). Although the association between COVID-19 and VSMCs is recognized, the precise mechanism underlying SARS-CoV-2's influence on VSMC phenotype remains largely under-reviewed. In this context, while there is a consistent body of literature dissecting the effect of COVID-19 on the cardiovascular system, few reports delve into the potential role of VSMC switching in the pathophysiology associated with COVID-19 and the molecular mechanisms involved therein. This review dissects and critiques the link between COVID-19 and VSMCs, with particular attention to pathways involving cholesterol, calcium, and phosphate. These pathways underpin the interaction between the virus and VSMCs. Such interaction promotes VSMC proliferation, and eventually potentiates vascular calcification as well as worsens prognosis in patients with COVID-19.

m6A Modification of Profilin-1 in Vascular Smooth Muscle Cells Drives Phenotype Switching and Neointimal Hyperplasia via Activation of the p-ANXA2/STAT3 Pathway

BACKGROUND

In-stent restenosis is characterized by a significant reduction in lumen diameter within the stented segment, primarily attributed to excessive proliferation of vascular smooth muscle cells (VSMCs) and neointimal hyperplasia. PFN1 (profilin-1), an actin-sequestering protein extensively studied in amyotrophic lateral sclerosis, remains less explored in neointimal hyperplasia.

METHODS

Utilizing single-cell RNA sequencing alongside data from in-stent restenosis patients and various experimental in-stent restenosis models (swine, rats, and mice), we investigated the role of PFN1 in promoting VSMC phenotype switching and neointimal hyperplasia.

RESULTS

Single-cell RNA sequencing of stenotic rat carotid arteries revealed a critical role for PFN1 in neointimal hyperplasia, a finding corroborated in stented swine coronary arteries, in-stent restenosis patients, PFN1SMC-IKO (SMC-specific PFN1 knockout) mice, and PFN1 overexpressed mice. PFN1 deletion was shown to suppress VSMC phenotype switching and neointimal hyperplasia in PFN1SMC-IKO mice subjected to a wire-injured model. To elucidate the observed discordance in PFN1 mRNA and protein levels, we identified that METTL3 (N6-methyladenosine methyltransferase) and YTHDF3 (YTH N6-methyladenosine RNA binding protein F3; N6-methyladenosine-specific reader) enhance PFN1 translation efficiency in an N6-methyladenosine-dependent manner, confirmed through experiments involving METTL3 knockout and YTHDF3 knockout mice. Furthermore, PFN1 was mechanistically found to interact with the phosphorylation of ANXA2 (annexin A2) by recruiting Src (SRC proto-oncogene, nonreceptor tyrosine kinase), promoting the phosphorylation of STAT3 (signal transducer and activator of transcription 3), a typical transcription factor known to induce VSMC phenotype switching.

CONCLUSIONS

This study unveils the significance of PFN1 N6-methyladenosine modification in VSMCs, demonstrating its role in promoting phenotype switching and neointimal hyperplasia through the activation of the p-ANXA2 (phospho-ANXA2)/STAT3 pathway.

Fosinopril inhibits Ang II-induced VSMC proliferation, phenotype transformation, migration, and oxidative stress through the TGF-β1/Smad signaling pathway

Fosinopril (FOS) is an angiotensin-converting enzyme inhibitor that can decrease angiotensin II (Ang II) formation, thereby reducing systemic vasoconstriction. This study investigated the impact of FOS on vascular smooth muscle cell (VSMC) phenotypic transformation in hypertension. Experiments using western blotting revealed that FOS inhibits the Ang II-induced downregulation of α-SMA and SM22α and the upregulation of OPN in VSMCs. In addition, CCK8 assays, EdU staining, and Transwell assays demonstrated that FOS reduces Ang II-induced increases in VSMC cell viability, proliferation, migration, and MMP2 and MMP9 expression. Moreover, immunofluorescence and ELISA experiments showed that FOS suppresses Ang II-induced increases in ROS levels, NAD(P)H activity, and NOX2 and NOX4 expression in VSMCs. Western blotting also indicated that FOS inhibits Ang II-induced increases in TGF-β1 and p-Smad2/3 expression in VSMCs. Finally, FOS mitigates Ang II-induced VSMC proliferation, phenotypic transformation, migration, and oxidative stress by inhibiting the TGF-β1/Smad signaling pathway. In conclusion, these results suggest that FOS could be effective in managing vascular diseases, including hypertension.

[circ_0084043/miR-31-5p Is Involved in Atherosclerosis by Regulating HMGA1: Investigation of the Mechanisms]

Objective

To explore the specific mechanism by which circ_0084043/miR-31-5p regulates high mobility group AT-hook 1 (HMGA1) and thus participates in atherosclerosis (AS).

Methods

Carotid plaque tissues, diseased vascular tissue, and corresponding normal tissue from areas adjacent to the plaques were collected from 49 AS patients between September 2020 and September 2023. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to determine circ_0084043 expression. The proliferation, migration, and invasion of vascular smooth muscle cells (VSMCs) induced by oxidized low-density lipoprotein (ox-LDL) were determined by CCK-8, clone formation, scratch, and Transwell assays. The targeted regulatory relationship among circ_0084043, miR-31-5p, and HMGA1 was verified by bioinformatics and dual luciferase reporter gene assay. An AS mouse model was established, and the pathological lesions in the aorta of AS model mice were observed by oil red O and HE stainings. Biochemical testing was performed to assess blood lipids in venous blood. qRT-PCR was used to determine the expression of miR-31-5p and HMGA1. Immunohistochemistry was performed to assess the expression of HMGA1 and α-smooth muscle actin (α-SMA) in the aorta of the AS model mice.

Results

In AS patients, the expression levels of circ_0084043 and HMGA1 in carotid plaque tissues and diseased vascular tissues were elevated (P<0.05), while the expression level of miR-31-5p was decreased (P<0.05). The expression of circ_0084043 was negatively correlated with the expression of miR-31-5p (r=－0.3855, P=0.0062). HMGA1 expression was positively correlated with circ_0084043 expression (r=0.3317, P=0.0199), and negatively correlated with miR-31-5p (r=－0.3351, P=0.0186). MiR-31-5p had target binding sites for both circ_0084043 and HMGA1. Compared with the control group, the proliferation, clone formation, migration, and invasion abilities of the sh-NC group, the scramble group, the circ_0084043+miR-31-5p mimics group, the miR-31-5p inhibitor+sh-HMGA1 group, and the circ_0084043+sh-HMGA1 group increased (P<0.05). In contrast, the proliferation, clone formation, migration, and invasion abilities of the sh-0084043 group significant decreased compared to those of the sh-NC group (P<0.05). The proliferation, clone formation, migration, and invasion abilities of the miR-31-5p mimics group and the sh-HMGA1 group decreased compared with those of the scramble group (P<0.05). Compared with the sh-NC group, sh-0084043 group had decreased aortic lipid plaque and necrotic core areas (P<0.05). Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and the expression levels of HMGA1 mRNA and protein and α-SMA decreased (P<0.05), while high-density lipoprotein cholesterol (HDL-C) and miR-31-5p expression levels increased (P<0.05).

Conclusion

circ_0084043 promotes the proliferation and migration of VSMCs and promotes the progress of AS by inhibiting miR-31-5p and increasing the expression of HMGA1.

HIF-1α knockdown attenuates phenotypic transformation and oxidative stress induced by high salt in human aortic vascular smooth muscle cells

Increased dietary salt intake is a well-established risk factor for hypertension and related cardiovascular diseases, involving complex vascular remodeling processes. However, the specific role of hypoxia-inducible factor-1α (HIF-1α) in vascular pathophysiology under high-salt conditions remains poorly understood. This study investigates the role of HIF-1α in high-salt-induced vascular remodeling using human aortic vascular smooth muscle cells (HA-VSMCs) cultured in vitro. HA-VSMCs were divided into three groups: high-salt with HIF-1α knockdown (shHIF-1α + HS), negative control (shcontrol), and high-salt (HS). Cell viability, migration, gene expression, and protein levels were evaluated. High-salt conditions significantly increased mRNA expression of α-smooth muscle actin (α-SMA), smooth muscle protein 22 (SM22), angiotensin II type 1 receptor (AT1R), collagen I, and collagen III (p < 0.0001). HIF-1α knockdown partially attenuated these increases, particularly for α-SMA, SM22, and AT1R (p < 0.01). At the protein level, high-salt exposure markedly elevated expression of collagen III, HIF-1α, osteopontin (OPN), and angiotensin II (Ang II) (p < 0.0001). HIF-1α knockdown significantly reduced the high-salt-induced increases in collagen III and HIF-1α protein levels (p < 0.001) but had a limited effect on OPN and Ang II upregulation. Interestingly, SM22 protein expression was significantly decreased under high-salt conditions (p < 0.0001), an effect partially reversed by HIF-1α knockdown (p < 0.0001). These findings demonstrate that high-salt conditions induce complex changes in gene and protein expression in HA-VSMCs, with HIF-1α playing a crucial role in mediating many of these alterations. The study highlights the differential effects of HIF-1α on various markers of vascular remodeling and suggests that HIF-1α may be a potential therapeutic target for mitigating salt-induced vascular pathology. Further research is warranted to elucidate the mechanisms underlying the HIF-1α-dependent and -independent effects observed in this study.

The role of dysbiotic gut mycobiota in modulating risk for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a large-vessel disease with high mortality, characterized by complex pathogenic mechanisms. Current therapeutic approaches remain insufficient to halt its progression. Fungi are important members of the gut microbiota. However, their characteristic alterations and roles in AAA remain unclear. This study investigated the role of gut fungal communities in the development of AAA through metagenomic sequencing of fecal samples from 31 healthy individuals and 33 AAA patients. We observed significant dysbiosis in the gut mycobiomes of AAA patients compared to healthy individuals, characterized by an increase in pathogenic fungi like Candida species and a decrease in beneficial yeasts such as Saccharomyces cerevisiae. The changes in fungal populations correlated strongly with clinical indicators of AAA, highlighting their potential for diagnosing and predicting AAA progression. Furthermore, our animal experiments demonstrated that Saccharomyces cerevisiae significantly ameliorated pathological alterations in AAA mice, suggesting a protective role for specific yeast strains against AAA development. These findings underscore the significant impact of gut mycobiomes on AAA and suggest that modulating these fungal communities could offer a novel therapeutic approach. Our research advances the understanding of the influence of gut microbiome on vascular diseases and suggests potential non-surgical approaches for managing AAA. By elucidating the diagnostic and therapeutic potential of gut fungi in AAA, this study provided important clues for future clinical strategies and therapeutic developments in the field of vascular medicine.

IMPORTANCE

Our research highlights the crucial role of gut fungi in abdominal aortic aneurysm (AAA) development. By analyzing fecal samples from AAA patients and healthy controls, we discovered significant dysbiosis in gut fungal communities, characterized by an increase in harmful Candida species and a decrease in beneficial yeasts like Saccharomyces cerevisiae. This dysbiosis was correlated with the severity of AAA. Importantly, in animal experiments, supplementing with Saccharomyces cerevisiae significantly slowed AAA progression. These findings suggest that modulating gut fungi may offer a novel, non-surgical approach to the diagnosis and treatment of AAA, potentially reducing the need for invasive procedures.

Gut microbiota-derived Metabolite, Shikimic Acid, inhibits vascular smooth muscle cell proliferation and migration

Gut microbiota dysbiosis is linked to vascular wall disease, but the mechanisms by which gut microbiota cross-talk with the host vascular cells remain largely unknown. Shikimic acid (SA) is a biochemical intermediate synthesized in plants and microorganisms, but not mammals. Surprisingly, recent metabolomic profiling data demonstrate that SA is detectable in human and murine blood. In this study, analyzing data from germ-free rats, we provide evidence in support of SA as a bona fide gut microbiota-derived metabolite, emphasizing its biological relevance. Since vascular cells are the first cells exposed to circulating metabolites, in this study, we examined, for the first time, the effects and potential underlying molecular mechanisms of SA on vascular smooth muscle cell (VSMC) proliferation and migration, which play a key role in occlusive vascular diseases, such as post-angioplasty restenosis and atherosclerosis. We found that SA inhibits the proliferation and migration of human coronary artery SMCs. At the molecular level, unexpectedly, we found that SA activates, rather than inhibits, multiple pro-mitogenic signaling pathways in VSMCs, such as ERK1/2, AKT, and mTOR/p70S6K. Conversely, we found that SA activates the anti-proliferative AMP-activated protein kinase (AMPK) in VSMCs, a key cellular energy sensor and regulator. However, loss-of-function experiments demonstrate that AMPK does not mediate the inhibitory effects of SA on VSMC proliferation. In conclusion, these studies demonstrate that a microbiota-derived metabolite, SA, inhibits VSMC proliferation and migration in vitro and prompt further evaluation of the possible underlying molecular mechanisms and the potential protective role in VSMC-related vascular wall disease in vivo.

Dysregulated Mitochondrial Calcium Causes Spiral Artery Remodeling Failure in Preeclampsia

BACKGROUND

Calcium deficiency in women is strongly linked to an increased risk of developing preeclampsia. Mitochondrial calcium ([Ca2+]m) homeostasis is essential to regulate vascular smooth muscle cell (VSMC) function. However, the role of [Ca2+]m in preeclampsia development remains largely unknown.

METHODS

To investigate this, human spiral arteries obtained from normotensive and preeclamptic women were collected for vascular function, RNA sequencing, and VSMC studies. N(ω)-nitro-L-arginine methyl ester-induced preeclampsia animal experiments were established to investigate the effects of intervening in [Ca2+]m to improve the outcome for preeclamptic mothers or their infants.

RESULTS

Our initial findings revealed compromised vessel function in spiral arteries derived from patients with preeclampsia, as evidenced by diminished vasoconstriction and vasodilation responses to angiotensin II and sodium nitroprusside, respectively. Moreover, the spiral artery VSMCs from patients with preeclampsia exhibited phenotypic transformation and proliferation associated with the disrupted regulatory mechanisms of [Ca2+]m uptake. Subsequent in vitro experiments employing gain- and loss-of-function approaches demonstrated that the mitochondrial Na+/Ca2+ exchanger played a role in promoting phenotypic switching and impaired mitochondrial functions in VSMCs. Furthermore, mtNCLX (mitochondrial Na+/Ca2+ exchanger) inhibitor CGP37157 significantly improved VSMC phenotypic changes and restored mitochondrial function in both patients with preeclampsia-derived VSMCs and the preeclampsia rat model.

CONCLUSIONS

This study provides comprehensive evidence supporting the disrupted regulatory mechanisms of [Ca2+]m uptake in VSMCs of spiral arteries of patients with preeclampsia and further elucidates its correlation with VSMC phenotypic switching and defective spiral artery remodeling. The findings suggest that targeting mtNCLX holds promise as a novel therapeutic approach for managing preeclampsia.

Function and mechanism of lysine crotonylation in health and disease

Lysine crotonylation is a newly identified posttranslational modification that is different from the widely studied lysine acetylation in structure and function. In the last dozen years, great progress has been made in lysine crotonylation-related studies, and lysine crotonylation is involved in reproduction, development and disease. In this review, we highlight the similarities and differences between lysine crotonylation and lysine acetylation. We also summarize the methods and tools for the detection and prediction of lysine crotonylation. At the same time, we outline the recent advances in understanding the mechanisms of enzymatic and metabolic regulation of lysine crotonylation, as well as the regulating factors that selectively recognize this modification. Particularly, we discussed how dynamic changes in crotonylation status maintain physiological health and result in the development of disease. This review not only points out the new functions of lysine crotonylation but also provides new insights and exciting opportunities for managing various diseases.

The Role of Cardio-Renal Inflammation in Deciding the Fate of the Arteriovenous Fistula in Haemodialysis Therapy

Vascular access is an indispensable component of haemodialysis therapy for end-stage kidney disease patients. The arteriovenous fistula (AVF) is most common, but importantly, two-year failure rates are greater than fifty percent. AVF failure can occur due to a lack of suitable vascular remodelling, and inappropriate inflammation preventing maturation, or alternatively neointimal hyperplasia and vascular stenosis preventing long-term use. A comprehensive mechanistic understanding of these processes is still lacking, but recent studies highlight an essential role for inflammation from uraemia and the AVF itself. Inflammation affects each cell in the cascade of AVF failure, the endothelium, the infiltrating immune cells, and the vascular smooth muscle cells. This review examines the role of inflammation in each cell step by step and the influence on AVF failure. Inflammation resulting in AVF failure occurs initially via changes in endothelial cell activation, permeability, and vasoprotective chemokine secretion. Resultingly, immune cells can extravasate into the subendothelial space to release inflammatory cytokines and cause other deleterious changes to the microenvironment. Finally, all these changes modify vascular smooth muscle cell function, resulting in excessive and unchecked hyperplasia and proliferation, eventually leading to stenosis and the failure of the AVF. Finally, the emerging therapeutic options based off these findings are discussed, including mesenchymal stem cells, small-molecule inhibitors, and far-infrared therapies. Recent years have clearly demonstrated a vital role for inflammation in deciding the fate of the AVF, and future works must be centred on this to develop therapies for a hitherto unacceptably underserved patient population.

Identification of the Neointimal Hyperplasia-Related LncRNA-mRNA-Immune Cell Regulatory Network in a Rat Carotid Artery Balloon Injury Model

Excessive neointimal hyperplasia (NIH) of coronary vessels in patients is the main cause of restenosis (RS) after percutaneous coronary intervention (PCI). This study aimed to identify the regulatory genes related to NIH in a rat carotid artery balloon injury model.We established a rat model and performed RNA sequencing to identify differentially expressed long non-coding RNAs (DElncRNAs) and differentially expressed message RNAs (DEmRNAs). Immune cells were analyzed using a murine Microenvironment Cell Population counter. The Pearson correlation between DEmRNAs, DElncRNAs, and immune cells was analyzed, followed by function enrichment analysis. Core DEmRNA was identified using Cytoscape. Next, a core lncRNAs-mRNAs-immune cell regulatory network was constructed. NIH-related gene sets from the Gene Expression Omnibus and GeneCards databases were used for validation.A total of 2,165 DEmRNAs and 705 DElncRNAs were identified in rat carotid artery tissue. Four key immune cells were screened out, including mast cells, vessels, endothelial cells, and fibroblasts. Based on the Pearson correlation between DEmRNAs, DElncRNAs and 4 key immune cells, 246 DEmRNAs and 93 DElncRNAs were obtained. DEmRNAs that interact with lncRNAs were mainly involved in the cell cycle, MAPK signaling pathway, and PI3K-Akt signaling pathway. A core lncRNA-mRNA-immune cell regulatory network was constructed, including 9 mRNAs, 4 lncRNAs, and fibroblasts. External datasets validation confirmed the significant correlation of both these mRNAs and lncRNAs with NIH.In this study, an lncRNA-mRNA-immune cell regulatory network related to NIH was constructed, which provided clues for exploring the potential mechanism of RS in cardiovascular diseases.

Transcriptomic and Multi-scale Network Analyses Reveal Key Drivers of Cardiovascular Disease

Cardiovascular diseases (CVDs) and pathologies are often driven by changes in molecular signaling and communication, as well as in cellular and tissue components, particularly those involving the extracellular matrix (ECM), cytoskeleton, and immune response. The fine-wire vascular injury model is commonly used to study neointimal hyperplasia and vessel stiffening, but it is not typically considered a model for CVDs. In this paper, we hypothesize that vascular injury induces changes in gene expression, molecular communication, and biological processes similar to those observed in CVDs at both the transcriptome and protein levels. To investigate this, we analyzed gene expression in microarray datasets from injured and uninjured femoral arteries in mice two weeks post-injury, identifying 1,467 significantly and differentially expressed genes involved in several CVDs such as including vaso-occlusion, arrhythmia, and atherosclerosis. We further constructed a protein-protein interaction network with seven functionally distinct clusters, with notable enrichment in ECM, metabolic processes, actin-based process, and immune response. Significant molecular communications were observed between the clusters, most prominently among those involved in ECM and cytoskeleton organizations, inflammation, and cell cycle. Machine Learning Disease pathway analysis revealed that vascular injury-induced crosstalk between ECM remodeling and immune response clusters contributed to aortic aneurysm, neovascularization of choroid, and kidney failure. Additionally, we found that interactions between ECM and actin cytoskeletal reorganization clusters were linked to cardiac damage, carotid artery occlusion, and cardiac lesions. Overall, through multi-scale bioinformatic analyses, we demonstrated the robustness of the vascular injury model in eliciting transcriptomic and molecular network changes associated with CVDs, highlighting its potential for use in cardiovascular research.

Nexilin in cardiomyopathy: unveiling its diverse roles with special focus on endocardial fibroelastosis

Cardiac disorders exhibit considerable heterogeneity, and understanding their genetic foundations is crucial for their diagnosis and treatment. Recent genetic analyses involving a growing number of participants have uncovered novel mutations within both coding and non-coding regions of DNA, contributing to the onset of cardiac conditions. The NEXN gene, encoding the Nexilin protein, an actin filament-binding protein, is integral to normal cardiac function. Mutations in this gene have been linked to cardiomyopathies, cardiovascular disorders, and sudden deaths. Heterozygous or homozygous variants of the NEXN gene are associated with the development of endocardial fibroelastosis (EFE), a rare cardiac condition characterized by excessive collagen and elastin deposition in the left ventricular endocardium predominantly affecting infants and young children. EFE occurs both primary and secondary to other conditions and often leads to unfavorable prognoses and outcomes. This review explores the role of NEXN genetic variants in cardiovascular disorders, particularly EFE, revealing that functional mutations are not clustered in a specific domain of Nexilin based on the cardiac disorder phenotype. Our review underscores the importance of understanding genetic mutations for the diagnosis and treatment of cardiac conditions.

Macrophages in vascular disease: Roles of mitochondria and metabolic mechanisms

Macrophages are a dynamic cell type of the immune system implicated in the pathophysiology of vascular diseases and are a major contributor to pathological inflammation. Excessive macrophage accumulation, activation, and polarization is observed in aortic aneurysm (AA), atherosclerosis, and pulmonary arterial hypertension. In general, macrophages become activated and polarized to a pro-inflammatory phenotype, which dramatically changes cell behavior to become pro-inflammatory and infiltrative. These cell types become cumbersome and fail to be cleared by normal mechanisms such as autophagy. The result is a hyper-inflammatory environment causing the recruitment of adjacent cells and circulating immune cells to further augment the inflammatory response. In AA, this leads to excessive ECM degradation and chemokine secretion, ultimately causing macrophages to dominate the immune cell landscape in the aortic wall. In atherosclerosis, monocytes are recruited to the vascular wall, where they polarize to the pro-inflammatory phenotype and induce inflammatory pathway activation. This leads to the development of foam cells, which significantly contribute to neointima and necrotic core formation in atherosclerotic plaques. Pro-inflammatory macrophages, which affect other vascular diseases, present with fragmented mitochondria and corresponding metabolic dysfunction. Targeting macrophage mitochondrial dynamics has proved to be an exciting potential therapeutic approach to combat vascular disease. This review will summarize mitochondrial and metabolic mechanisms of macrophage activation, polarization, and accumulation in vascular diseases.

Fe3O4 coated stent prevent artery neointimal hyperplasia by inhibiting vascular smooth muscle cell proliferation

In-stent restenosis (ISR), caused by aggressive vascular smooth muscle cell (VSMC) proliferation, is a serious complication of stenting. Therefore, developing therapeutic approaches that target VSMC inhibition is imperative. Our previous study showed that VSMC hyperplasia was attenuated after iron stent degradation, and VSMC proliferation around the stented section was arrested. The corrosion products of the iron stents were primarily Fe3O4 particles. Therefore, we hypothesized that Fe3O4 particles generated by iron stents would prevent neointimal hyperplasia by inhibiting VSMC proliferation. To test this hypothesis, culture assays and flow cytometry were performed to investigate the proliferation of VSMC. Global gene sequencing and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to investigate the underlying mechanisms. Fe3O4-coated stents were implanted into rabbit carotid arteries to evaluate the inhibitory effects of Fe3O4 on neointimal hyperplasia. The major findings of the study were as follows: 1) Fe3O4 attenuated neointimal hyperplasia by preventing VSMC proliferation after stenting; 2) Fe3O4 exerted inhibitory effects on VSMCs by downregulating proliferative genes such as SOX9, EGR4, and TGFB1, but upregulated inhibitory genes such as DNMT1, TIMP3, and PCNA; 3) Fe3O4 inhibited VSMCs by preventing phenotypic transformation from the contractile to the synthetic phase; and 4) Fe3O4-coated stents achieved satisfactory hemocompatibility in a rabbit model. Our study highlights the additional benefits of Fe3O4 particles in inhibiting VSMC proliferation, indicating that Fe3O4 coated stent potentially served as an attractive therapeutic approach for ISR prevention.

Circ_0008571 modulates the phenotype of vascular smooth muscle cells by targeting miR-145-5p in intracranial aneurysms

BACKGROUND

The dysfunction of human vascular smooth cells (hVSMCs) is significantly connected to the development of intracranial aneurysms (IAs). By suppressing the activity of microRNAs (miRNAs), circular RNAs (circRNAs) participate in IA pathogenesis. Nevertheless, the role of hsa_circ_0008571 in IAs remains unclear.

METHODS

circRNA sequencing was used to identify circRNAs from human IA tissues. To determine the function of circ_0008571, Transwell, wound healing, and cell proliferation assays were conducted. To identify the target of circ_0008571, the analyses of CircInteractome and TargetScan, as well as the luciferase assay were carried out. Furthermore, circ_0008571 knockdown and over-expression were performed to investigate its functions in IA development and the underlying molecular mechanisms.

RESULTS

Both hsa_circ_0008571 and Integrin beta 8 (ITGB8) were downregulated, while miR-145-5p transcription was elevated in the aneurysm wall of IAs patients compared to superficial temporal artery tissues. In vitro, cell migration and growth were dramatically suppressed after hsa_circ_0008571 overexpression. Mechanistically, has_circ_0008571 could suppress miR-145-5p activity by direct sponging. Moreover, we found that ITGB8 expression and the activation of the TGF-β-mediated signaling pathway were significantly enhanced.

CONCLUSION

The hsa_circ_0008571-miR-145-5p-ITGB8 axis plays an essential role in IA progression.

NEAT1 regulates VSMC differentiation and calcification in as long noncoding RNA NEAT1 enhances phenotypic and osteogenic switching of vascular smooth muscle cells in atherosclerosis via scaffolding EZH2

Atherosclerosis (AS) is a significant contributor to cardio-cerebrovascular ischemia diseases, resulting in high mortality rates worldwide. During AS, vascular smooth muscle cells (VSMCs) play a crucial role in plaque formation by undergoing phenotypic and osteogenic switching. Long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has previously been identified as a nuclear regulator that promotes tumorigenesis and metastasis, but its role in regulating VSMCs in AS remains unclear. Our study aimed to investigate the biological functions and specific mechanisms of NEAT1 in regulating VSMCs in AS. We found that NEAT1 was upregulated in the aortas of AS mouse models and dedifferentiated primary VSMCs. Silencing NEAT1 in vitro attenuated the proliferation, migration, and osteogenic differentiation of VSMCs, while NEAT1 overexpression had the opposite effect. Furthermore, NEAT1 promoted VSMC osteogenic differentiation and vascular calcification in both in vivo and in vitro vascular calcification models. We also discovered that NEAT1 directly activates enhancer of zeste homolog 2 (EZH2), an epigenetic enzyme that suppresses the expression of senescence- and antimigration-related genes, by translocating it into the nucleus. CUT&Tag assay revealed that NEAT1 guides EZH2 to the promoters of senescence-related genes (P16, P21, and TIMP3), methylating local histones to reduce their transcription. Our findings suggest that NEAT1 functions in AS by modulating the epigenetic function of EZH2, which enhances the proliferation, migration, and osteogenic differentiation of VSMCs. This study provides new insights into the molecular mechanisms underlying the pathogenesis of AS and highlights the potential of NEAT1 as a therapeutic target of AS.NEW & NOTEWORTHY Our study demonstrates that the upregulation of long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) promotes proliferation and migration during phenotypic switching of vascular smooth muscle cells in atherosclerosis. We also provide in vivo and in vitro evidence that NEAT1 accelerates vascular calcification. Our findings identified the direct interaction between enhancer of zeste homolog 2 (EZH2) and NEAT1 during atherosclerosis. NEAT1 is necessary for EZH2 to translocate from the cytoplasm to the nucleus, where EZH2 epigenetically inhibits the expression of genes related to senescence and antimigration.

Recent Translational Research Models of Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is a leading cause of ischemic stroke worldwide. However, research on the pathophysiology of ICAD is scarce due to the relative inaccessibility of histology samples and the lack of comprehensive experimental models. As a result, much of the current understanding of ICAD relies on research on extracranial atherosclerosis. This approach is problematic as intracranial and extracranial arteries are anatomically, structurally, physiologically, and metabolically distinct, indicating that intracranial and extracranial atherosclerosis likely develop through different biologic pathways. The current standard of care for ICAD treatment relies predominantly on therapeutics developed to treat extracranial atherosclerosis and is insufficient given the alarmingly high risk of stroke. To provide a definitive treatment for the disease, a deeper understanding of the pathophysiology underlying ICAD is specifically required. True mechanistic understanding of disease pathogenesis is only possible using robust experimental models. In this review, we aim to identify the advantages and limitations of the existing in vivo and in vitro models of ICAD and basic atherosclerotic processes, which may be used to inform better models of ICAD in the future and drive new therapeutic strategies to reduce stroke risk.

Fabric-Enhanced Vascular Graft with Hierarchical Structure for Promoting the Regeneration of Vascular Tissue

Natural blood vessels have completed functions, including elasticity, compliance, and excellent antithrombotic properties because of their mature structure. To replace damaged blood vessels, vascular grafts should perform these functions by simulating the natural vascular structures. Although the structures of natural blood vessels are thoroughly explored, constructing a small-diameter vascular graft that matches the mechanical and biological properties of natural blood vessels remains a challenge. A hierarchical vascular graft is fabricated by Electrospinning, Braiding, and Thermally induced phase separation (EBT) processes, which could simulate the structure of natural blood vessels. The internal electrospun structure facilitates the adhesion of endothelial cells, thereby accelerating endothelialization. The intermediate PLGA fabric exhibits excellent mechanical properties, which allow it to maintain its shape during long-term transplantation and prevent graft expansion. The external macroporous structure is beneficial for cell growth and infiltration. Blood vessel remodeling aims to combine a structure that promotes tissue regeneration with anti-inflammatory materials. The results in vitro demonstrated that it EBT vascular graft (EBTVG) has matched the mechanical properties, reliable cytocompatibility, and the strongest endothelialization in situ. The results in vitro and replacement of the resected artery in vivo suggest that the EBTVG combines different structural advantages with biomechanical properties and reliable biocompatibility, significantly promoting the stabilization and regeneration of vascular endothelial cells and vascular smooth muscle cells, as well as stabilizing the blood microenvironment.

Chronotherapy involving rosiglitazone regulates the phenotypic switch of vascular smooth muscle cells by shifting the phase of TNF-α rhythm through triglyceride accumulation in macrophages

Objectives

Vascular diseases are often caused by the interaction between macrophages and vascular smooth muscle cells (VSMCs). This study aims to elucidate whether chronotherapy with rosiglitazone (RSG) can regulate the secretion rhythm of macrophages, thereby controlling the phenotypic switch of VSMCs and clarifying the potential molecular mechanisms, providing a chronotherapeutic approach for the treatment of vascular diseases.

Methods

RAW264.7 cells and A7r5 cells were synchronized via a 50 % FBS treatment. M1-type macrophages were induced through Lipopolysaccharide (LPS) exposure. Additionally, siRNA and plasmids targeting PPARγ were transfected into macrophages. The assessment encompassed cell viability, migration, inflammatory factor levels, lipid metabolites, clock gene expression, and relative protein expression.

Results

We revealed that, in alignment with core clock genes Bmal1 and CLOCK, RSG administration at ZT2 advanced the phase of TNF-α release rhythm, while ZT12 administration shifted it backward. Incubation with TNF-α at ZT2 significantly promoted the phenotype switch of VSMCs. This effect diminished when incubated at ZT12, implicating the involvement of the clock-MAPK pathway in VSMCs. Furthermore, RSG administration at ZT2 advanced the phases of PPARγ and Bmal1 genes, whereas ZT12 administration shifted them backward. Additionally, PPARγ overexpression significantly induced triglyceride (TG) accumulation in macrophages. Exogenous TG upregulated Bmal1 and CLOCK gene expression in macrophages and significantly increased TNF-α release.

Conclusion

Chronotherapy involving RSG induces TG accumulation within macrophages, resulting in alterations in circadian gene rhythms. These changes, in turn, modulate the phase of rhythmic TNF-α release and play a regulatory role in VSMCs phenotype switch. Our study establishes a theoretical foundation for chronotherapy of PPARγ agonists.

Elucidating VSMC phenotypic transition mechanisms to bridge insights into cardiovascular disease implications

Cardiovascular diseases (CVD) are the leading cause of death worldwide, despite advances in understanding cardiovascular health. Significant barriers still exist in effectively preventing and managing these diseases. Vascular smooth muscle cells (VSMCs) are crucial for maintaining vascular integrity and can switch between contractile and synthetic functions in response to stimuli such as hypoxia and inflammation. These transformations play a pivotal role in the progression of cardiovascular diseases, facilitating vascular modifications and disease advancement. This article synthesizes the current understanding of the mechanisms and signaling pathways regulating VSMC phenotypic transitions, highlighting their potential as therapeutic targets in cardiovascular disease interventions.

KLF13 promotes VSMCs phenotypic dedifferentiation by directly binding to the SM22α promoter

Krüppel-like factor 13 (KLF13), a zinc finger transcription factor, is considered as a potential regulator of cardiomyocyte differentiation and proliferation during heart morphogenesis. However, its precise role in the dedifferentiation of vascular smooth muscle cells (VSMCs) during atherosclerosis and neointimal formation after injury remains poorly understood. In this study, we investigated the relationship between KLF13 and SM22α expression in normal and atherosclerotic plaques by bioanalysis, and observed a significant increase in KLF13 levels in the atherosclerotic plaques of both human patients and ApoE-/- mice. Knockdown of KLF13 was found to ameliorate intimal hyperplasia following carotid artery injury. Furthermore, we discovered that KLF13 directly binds to the SM22α promoter, leading to the phenotypic dedifferentiation of VSMCs. Remarkably, we observed a significant inhibition of platelet-derived growth factor BB-induced VSMCs dedifferentiation, proliferation, and migration when knocked down KLF13 in VSMCs. This inhibitory effect of KLF13 knockdown on VCMC function was, at least in part, mediated by the inactivation of p-AKT signaling in VSMCs. Overall, our findings shed light on a potential therapeutic target for treating atherosclerotic lesions and restenosis after vascular injury.

Mineralocorticoid Receptors in Vascular Smooth Muscle: Blood Pressure and Beyond

After half a century of evidence suggesting the existence of mineralocorticoid receptors (MR) in the vasculature, the advent of technology to specifically knockout the MR from smooth muscle cells (SMCs) in mice has elucidated contributions of SMC-MR to cardiovascular function and disease, independent of the kidney. This review summarizes the latest understanding of the molecular mechanisms by which SMC-MR contributes to (1) regulation of vasomotor function and blood pressure to contribute to systemic and pulmonary hypertension; (2) vascular remodeling in response to hypertension, vascular injury, obesity, and aging, and the impact on vascular calcification; and (3) cardiovascular pathologies including aortic aneurysm, heart valve dysfunction, and heart failure. Data are reviewed from in vitro studies using SMCs and in vivo findings from SMC-specific MR-knockout mice that implicate target genes and signaling pathways downstream of SMC-MR. By regulating expression of the L-type calcium channel subunit Cav1.2 and angiotensin II type-1 receptor, SMC-MR contributes to myogenic tone and vasoconstriction, thereby contributing to systemic blood pressure. MR activation also promotes SMC proliferation, migration, production and degradation of extracellular matrix, and osteogenic differentiation by regulating target genes including connective tissue growth factor, osteopontin, bone morphogenetic protein 2, galectin-3, and matrix metallopeptidase-2. By these mechanisms, SMC-MR promotes disease progression in models of aging-associated vascular stiffness, vascular calcification, mitral and aortic valve disease, pulmonary hypertension, and heart failure. While rarely tested, when sexes were compared, the mechanisms of SMC-MR-mediated disease were sexually dimorphic. These advances support targeting SMC-MR-mediated mechanisms to prevent and treat diverse cardiovascular disorders.

Asprosin aggravates atherosclerosis via regulating the phenotype transformation of vascular smooth muscle cells

Phenotype transformation of vascular smooth muscle cells (VSMCs) plays an important role in the development of atherosclerosis. Asprosin is a newly discovered adipokine, which is critical in regulating metabolism. However, the relationship between asprosin and phenotype transformation of VSMCs in atherosclerosis remains unclear. The aim of this study is to investigate whether asprosin affects the progression of atherosclerosis by inducing phenotype transformation of VSMCs. We established an atherosclerosis model in ApoE-/- mice and administered asprosin recombinant protein and asprosin antibody to mice. Knocking down asprosin was also as an intervention. Interestingly, we found a correlation between asprosin levels and atherosclerosis. Asprosin promoted plaque formation and phenotype transformation of VSMCs. While, AspKD or asprosin antibody reduced the plaque lesion and suppressed vascular stiffness in ApoE-/- mice. Mechanistically, asprosin induced phenotype transformation of MOVAs by binding to GPR54, leading to Gαq/11 recruitment and activation of the PLC-PKC-ERK1/2-STAT3 signaling pathway. Si GPR54 or GPR54 antagonist partially inhibited the action of asprosin in MOVAs. Mutant GPR54-(267, 307) residue cancelled the binding of asprosin and GPR54. In summary, this study confirmed asprosin activated GPR54/Gαq/11-dependent ERK1/2-STAT3 signaling pathway, thereby promoting VSMCs phenotype transformation and aggravating atherosclerosis, thus providing a new target for the treatment of atherosclerosis.

MTMR7 suppresses the phenotypic switching of vascular smooth muscle cell and vascular intimal hyperplasia after injury via regulating p62/mTORC1-mediated glucose metabolism

BACKGROUND AND AIMS

Myotubularin-related protein 7 (MTMR7) suppresses proliferation in various cell types and is associated with cardiovascular and cerebrovascular diseases. However, whether MTMR7 regulates vascular smooth muscle cell (VSMC) and vascular intimal hyperplasia remains unclear. We explored the role of MTMR7 in phenotypic switching of VSMC and vascular intimal hyperplasia after injury.

METHODS AND RESULTS

MTMR7 expression was significantly downregulated in injured arteries. Compared to wild type (WT) mice, Mtmr7-transgenic (Mtmr7-Tg) mice showed reduced intima/media ratio, decreased percentage of Ki-67-positive cells within neointima, and increased Calponin expression in injured artery. In vitro, upregulating MTMR7 by Len-Mtmr7 transfection inhibited platelet derived growth factor (PDGF)-BB-induced proliferation, migration of VSMC and reversed PDGF-BB-induced decrease in expression of Calponin and SM-MHC. Microarray, single cell sequence, and other bioinformatics analysis revealed that MTMR7 is highly related to glucose metabolism and mammalian target of rapamycin complex 1 (mTORC1). Further experiments confirmed that MTMR7 markedly repressed glycolysis and mTORC1 activity in PDGF-BB-challenged VSMC in vitro. Restoring mTORC1 activity abolished MTMR7-mediated suppression of glycolysis, phenotypic shift in VSMC in vitro and protection against vascular intimal hyperplasia in vivo. Furthermore, upregulating MTMR7 in vitro led to dephosphorylation and dissociation of p62 from mTORC1 in VSMC. External expression of p62 in vitro also abrogated the inhibitory effects of MTMR7 on glycolysis and phenotypic switching in PDGF-BB-stimulated VSMC.

CONCLUSIONS

Our study demonstrates that MTMR7 inhibits injury-induced vascular intimal hyperplasia and phenotypic switching of VSMC. Mechanistically, the beneficial effects of MTMR7 are conducted via suppressing p62/mTORC1-mediated glycolysis.

ADORA3: A Key Player in the Pathogenesis of Intracranial Aneurysms and a Potential Diagnostic Biomarker

BACKGROUND

The effects of genes on the development of intracranial aneurysms (IAs) remain to be elucidated, and reliable blood biomarkers for diagnosing IAs are yet to be established. This study aimed to identify genes associated with IAs pathogenesis and explore their diagnostic value by analyzing IAs datasets, conducting vascular smooth muscle cells (VSMC) experiments, and performing blood detection.

METHODS

IAs datasets were collected and the differentially expressed genes were analyzed. The selected genes were validated in external datasets. Autophagy was induced in VSMC and the effect of selected genes was determined. The diagnostic value of selected gene on the IAs were explored using area under curve (AUC) analysis using IAs plasma samples.

RESULTS

Analysis of 61 samples (32 controls and 29 IAs tissues) revealed a significant increase in expression of ADORA3 compared with normal tissues using empirical Bayes methods of "limma" package; this was further validated by two external datasets. Additionally, induction of autophagy in VSMC lead to upregulation of ADORA3. Conversely, silencing ADORA3 suppressed VSMC proliferation and autophagy. Furthermore, analysis of an IAs blood sample dataset and clinical plasma samples demonstrated increased ADORA3 expression in patients with IA compared with normal subjects. The diagnostic value of blood ADORA3 expression in IAs was moderate when analyzing clinical samples (AUC: 0.756). Combining ADORA3 with IL2RB or CCR7 further enhanced the diagnostic ability for IAs, with the AUC value over 0.83.

CONCLUSIONS

High expression of ADORA3 is associated with IAs pathogenesis, likely through its promotion of VSMC autophagy. Furthermore, blood ADORA3 levels have the potential to serve as an auxiliary diagnostic biomarker for IAs.

The challenges and prospects of smooth muscle tissue engineering

Many vascular disorders arise as a result of dysfunctional smooth muscle cells. Tissue engineering strategies have evolved as key approaches to generate functional vascular smooth muscle cells for use in cell-based precision and personalized regenerative medicine approaches. This article highlights some of the challenges that exist in the field and presents some of the prospects for translating research advancements into therapeutic modalities. The article emphasizes the need for better developing synergetic intracellular and extracellular cues in the processes to generate functional vascular smooth muscle cells from different stem cell sources for use in tissue engineering strategies.

EGR1 transcriptionally regulates SVEP1 to promote proliferation and migration in human coronary artery smooth muscle cells

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1) is associated with the risk of coronary artery disease, as determined by a genome-wide association study. SVEP1 induces vascular smooth muscle cell proliferation and an inflammatory phenotype to promote atherosclerosis. In the present study, qRT‒PCR demonstrated that the mRNA expression of SVEP1 was significantly increased in atherosclerotic plaques compared to normal tissues. Bioinformatics revealed that EGR1 was a transcription factor for SVEP1. The results of the luciferase reporter assay, siRNA interference or overexpression assay, mutational analysis and ChIP confirmed that EGR1 positively regulated the transcriptional activity of SVEP1 by directly binding to its promoter. EGR1 promoted human coronary artery smooth muscle cell (HCASMC) proliferation and migration via SVEP1 in response to oxidized low-density lipoprotein (ox-LDL) treatment. Moreover, the expression level of EGR1 was increased in atherosclerotic plaques and showed a strong linear correlation with the expression of SVEP1. Our findings indicated that EGR1 binding to the promoter region drive SVEP1 transcription to promote HCASMC proliferation and migration.

Effect of tissue factor pathway inhibitor on the pyroptosis of vascular smooth muscle cells induced by angiotensin II

Background

In recent years, a mass of studies have shown that pyroptosis plays an important role in the proliferation of vascular smooth muscle cells (VSMCs). We investigated whether angiotensin II (Ang II) induces the pyroptosis of rat aortic VSMCs and the role of NOD-like receptor family pyrin domain containing 3 (NLRP3) in this process. Additionally, we explored the effect and related mechanism of recombinant tissue factor pathway inhibitor (rTFPI) in Ang II-induced VSMC pyroptosis.

Methods

Cultured VSMCs were divided into five groups: control group, Ang II group (1×10-5 mol/L), MCC950 group (NLRP3 inhibitor, 15 nmol/L), Ang II + MCC950 group and Ang II + rTFPI (50 µg/L) group. Cell viability was measured by cell counting kit-8 (CCK8) assays and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays. Propidium iodide (PI) staining and immunofluorescence were performed to determine the pyroptosis of VSMCs. Changes in VSMC ultrastructure were evaluated through transmission electron microscopy. The expression levels of NLRP3, pro-caspase-1, gasdermin D-N (GSDMD-N), and interleukin-1β (IL-1β) were determined by western blot analysis.

Results

The cell viability, the positive rate of PI staining, and the expression level of GSDMD detected by immunofluorescence in the Ang II group were higher than that in the control group, whereas they all decreased in Ang II + MCC950 group and Ang II + rTFPI group compared with Ang II group (P<0.05). Electron microscopy analysis revealed less extracellular matrix, increased myofilaments, and decreased endoplasmic reticulum, Golgi complex, and mitochondria in Ang II + rTFPI-treated VSMCs than in Ang II-treated VSMCs. The protein expression levels of the pyroptosis-related molecules NLRP3, pro-caspase-1, GSDMD-N, and IL-1β in Ang II group showed an increasing trend compared with those in control group (P<0.05); however, these expression levels in Ang II + MCC950 and Ang II + rTFPI groups were significantly lower than those in Ang II group (P<0.05).

Conclusions

Ang II may induce pyroptosis in VSMCs by activating NLRP3. rTFPI can inhibit Ang II-induced VSMC pyroptosis. Furthermore, rTFPI might exert this effect by inhibiting the NLRP3 pathway and therefore play an important role in the treatment of vascular remodeling induced by hypertension.

The Mineralocorticoid Receptor in the Vasculature: Friend or Foe?

Originally described as the renal aldosterone receptor that regulates sodium homeostasis, it is now clear that mineralocorticoid receptors (MRs) are widely expressed, including in vascular endothelial and smooth muscle cells. Ample data demonstrate that endothelial and smooth muscle cell MRs contribute to cardiovascular disease in response to risk factors (aging, obesity, hypertension, atherosclerosis) by inducing vasoconstriction, vascular remodeling, inflammation, and oxidative stress. Extrapolating from its role in disease, evidence supports beneficial roles of vascular MRs in the context of hypotension by promoting inflammation, wound healing, and vasoconstriction to enhance survival from bleeding or sepsis. Advances in understanding how vascular MRs become activated are also reviewed, describing transcriptional, ligand-dependent, and ligand-independent mechanisms. By synthesizing evidence describing how vascular MRs convert cardiovascular risk factors into disease (the vascular MR as a foe), we postulate that the teleological role of the MR is to coordinate responses to hypotension (the MR as a friend).

Vascular injury activates the ELK1/SND1/SRF pathway to promote vascular smooth muscle cell proliferative phenotype and neointimal hyperplasia

BACKGROUND

Vascular smooth muscle cell (VSMC) proliferation is the leading cause of vascular stenosis or restenosis. Therefore, investigating the molecular mechanisms and pivotal regulators of the proliferative VSMC phenotype is imperative for precisely preventing neointimal hyperplasia in vascular disease.

METHODS

Wire-induced vascular injury and aortic culture models were used to detect the expression of staphylococcal nuclease domain-containing protein 1 (SND1). SMC-specific Snd1 knockout mice were used to assess the potential roles of SND1 after vascular injury. Primary VSMCs were cultured to evaluate SND1 function on VSMC phenotype switching, as well as to investigate the mechanism by which SND1 regulates the VSMC proliferative phenotype.

RESULTS

Phenotype-switched proliferative VSMCs exhibited higher SND1 protein expression compared to the differentiated VSMCs. This result was replicated in primary VSMCs treated with platelet-derived growth factor (PDGF). In the injury model, specific knockout of Snd1 in mouse VSMCs reduced neointimal hyperplasia. We then revealed that ETS transcription factor ELK1 (ELK1) exhibited upregulation and activation in proliferative VSMCs, and acted as a novel transcription factor to induce the gene transcriptional activation of Snd1. Subsequently, the upregulated SND1 is associated with serum response factor (SRF) by competing with myocardin (MYOCD). As a co-activator of SRF, SND1 recruited the lysine acetyltransferase 2B (KAT2B) to the promoter regions leading to the histone acetylation, consequently promoted SRF to recognize the specific CArG motif, and enhanced the proliferation- and migration-related gene transcriptional activation.

CONCLUSIONS

The present study identifies ELK1/SND1/SRF as a novel pathway in promoting the proliferative VSMC phenotype and neointimal hyperplasia in vascular injury, predisposing the vessels to pathological remodeling. This provides a potential therapeutic target for vascular stenosis.

Microvascular smooth muscle cells exhibit divergent phenotypic switching responses to platelet-derived growth factor and insulin-like growth factor 1

OBJECTIVE

Vascular smooth muscle cell (VSMC) phenotypic switching is critical for normal vessel formation, vascular stability, and healthy brain aging. Phenotypic switching is regulated by mediators including platelet derived growth factor (PDGF)-BB, insulin-like growth factor (IGF-1), as well as transforming growth factor-β (TGF-β) and endothelin-1 (ET-1), but much about the role of these factors in microvascular VSMCs remains unclear.

METHODS

We used primary rat microvascular VSMCs to explore PDGF-BB- and IGF-1-induced phenotypic switching.

RESULTS

PDGF-BB induced an early proliferative response, followed by formation of polarized leader cells and rapid, directionally coordinated migration. In contrast, IGF-1 induced cell hypertrophy, and only a small degree of migration by unpolarized cells. TGF-β and ET-1 selectively inhibit PDGF-BB-induced VSMC migration primarily by repressing migratory polarization and formation of leader cells. Contractile genes were downregulated by both growth factors, while other genes were differentially regulated by PDGF-BB and IGF-1.

CONCLUSIONS

These studies indicate that PDGF-BB and IGF-1 stimulate different types of microvascular VSMC phenotypic switching characterized by different modes of cell migration. Our studies are consistent with a chronic vasoprotective role for IGF-1 in VSMCs in the microvasculature while PDGF is more involved in VSMC proliferation and migration in response to acute activities such as neovascularization. Better understanding of the nuances of the phenotypic switching induced by these growth factors is important for our understanding of a variety of microvascular diseases.

The Role of TRIM Proteins in Vascular Disease

There are more than 80 different tripartite motifs (TRIM) proteins within the E3 ubiquitin ligase subfamily, including proteins that regulate intracellular signaling, apoptosis, autophagy, proliferation, inflammation, and immunity through the ubiquitination of target proteins. Studies conducted in recent years have unraveled the importance of TRIM proteins in the pathophysiology of vascular diseases. In this review, we describe the effects of TRIM proteins on vascular endothelial cells, smooth muscle cells, heart, and lungs. In particular, we discuss the potential mechanisms by which TRIMs regulate diseases and shed light on the potential therapeutic applications of TRIMs.

Dual-Specificity Phosphatase 6 Deficiency Attenuates Arterial-Injury-Induced Intimal Hyperplasia in Mice

In response to injury, vascular smooth muscle cells (VSMCs) of the arterial wall dedifferentiate into a proliferative and migratory phenotype, leading to intimal hyperplasia. The ERK1/2 pathway participates in cellular proliferation and migration, while dual-specificity phosphatase 6 (DUSP6, also named MKP3) can dephosphorylate activated ERK1/2. We showed that DUSP6 was expressed in low baseline levels in normal arteries; however, arterial injury significantly increased DUSP6 levels in the vessel wall. Compared with wild-type mice, Dusp6-deficient mice had smaller neointima. In vitro, IL-1β induced DUSP6 expression and increased VSMC proliferation and migration. Lack of DUSP6 reduced IL-1β-induced VSMC proliferation and migration. DUSP6 deficiency did not affect IL-1β-stimulated ERK1/2 activation. Instead, ERK1/2 inhibitor U0126 prevented DUSP6 induction by IL-1β, indicating that ERK1/2 functions upstream of DUSP6 to regulate DUSP6 expression in VSMCs rather than downstream as a DUSP6 substrate. IL-1β decreased the levels of cell cycle inhibitor p27 and cell-cell adhesion molecule N-cadherin in VSMCs, whereas lack of DUSP6 maintained their high levels, revealing novel functions of DUSP6 in regulating these two molecules. Taken together, our results indicate that lack of DUSP6 attenuated neointima formation following arterial injury by reducing VSMC proliferation and migration, which were likely mediated via maintaining p27 and N-cadherin levels.

MicroRNA-30a-3p: a potential noncoding RNA target for the treatment of arteriosclerosis obliterans

An increasing number of studies have shown that noncoding RNAs are involved in cardiovascular diseases. Our study shows that the expression of microRNA-30a-3p (miR-30a-3p) in patients with arteriosclerosis obliterans (ASO) of the lower extremities is significantly decreased after endovascular treatment, but its role is unclear. This study aims to explore the role of microRNA-30a-3p in ASO and its related mechanisms. Immunofluorescence and in situ hybridization costaining indicated that microRNA-30a-3p mostly exists in vascular smooth muscle cells (VSMCs). Furthermore, after transfection into VSMCs, microRNA-30a-3p inhibited VSMC proliferation, migration and phenotype switching. In addition, luciferase reporter and western blot analyses indicated that ROCK2 (Rho-related spiral coil 2 containing protein kinase) is a microRNA-30a-3p target gene, and participates in the microRNA-30a-3p mediated cell inhibitory effect. At last, the rat carotid artery was infected by lentivirus after balloon injury, which increased microRNA-30a-3p levels and apparently suppressed the formation of neointima in vivo. Overall, exogenous introduction of microRNA-30a-3p, a noncoding RNA with unlimited potential, may be a new approach to treat ASO.

Far-Infrared Irradiation Decreases Proliferation in Basal and PDGF-Stimulated VSMCs Through AMPK-Mediated Inhibition of mTOR/p70S6K Signaling Axis

BACKGROUND

Far-infrared (FIR) irradiation has been reported to improve diverse cardiovascular diseases, including heart failure, hypertension, and atherosclerosis. The dysregulated proliferation of vascular smooth muscle cells (VSMCs) is well established to contribute to developing occlusive vascular diseases such as atherosclerosis and in-stent restenosis. However, the effects of FIR irradiation on VSMC proliferation and the underlying mechanism are unclear. This study investigated the molecular mechanism through which FIR irradiation inhibited VSMC proliferation.

METHODS

We performed cell proliferation and cell death assay, adenosine 5'-triphosphate (ATP) assay, inhibitor studies, transfection of dominant negative (dn)-AMP-activated protein kinase (AMPK) α1 gene, and western blot analyses. We also conducted confocal microscopic image analyses and ex vivo studies using isolated rat aortas.

RESULTS

FIR irradiation for 30 minutes decreased VSMC proliferation without altering the cell death. Furthermore, FIR irradiation accompanied decreases in phosphorylation of the mammalian target of rapamycin (mTOR) at Ser2448 (p-mTOR-Ser2448) and p70 S6 kinase (p70S6K) at Thr389 (p-p70S6K-Thr389). The phosphorylation of AMPK at Thr172 (p-AMPK-Thr172) was increased in FIR-irradiated VSMCs, which was accompanied by a decreased cellular ATP level. Similar to in vitro results, FIR irradiation increased p-AMPK-Thr172 and decreased p-mTOR-Ser2448 and p-p70S6K-Thr389 in isolated rat aortas. Pre-treatment with compound C, a specific AMPK inhibitor, or ectopic expression of dn-AMPKα1 gene, significantly reversed FIR irradiation-decreased VSMC proliferation, p-mTOR-Ser2448, and p-p70S6K-Thr389. On the other hand, hyperthermal stimulus (39°C) did not alter VSMC proliferation, cellular ATP level, and AMPK/mTOR/p70S6K phosphorylation. Finally, FIR irradiation attenuated platelet-derived growth factor (PDGF)-stimulated VSMC proliferation by increasing p-AMPK-Thr172, and decreasing p-mTOR-Ser2448 and p-p70S6K-Thr389 in PDGF-induced in vitro atherosclerosis model.

CONCLUSION

These results show that FIR irradiation decreases the basal and PDGF-stimulated VSMC proliferation, at least in part, by the AMPK-mediated inhibition of mTOR/p70S6K signaling axis irrespective of its hyperthermal effect. These observations suggest that FIR therapy can be used to treat arterial narrowing diseases, including atherosclerosis and in-stent restenosis.

Model Systems to Study the Mechanism of Vascular Aging

Cardiovascular diseases are the leading cause of death globally. Within cardiovascular aging, arterial aging holds significant importance, as it involves structural and functional alterations in arteries that contribute substantially to the overall decline in cardiovascular health during the aging process. As arteries age, their ability to respond to stress and injury diminishes, while their luminal diameter increases. Moreover, they experience intimal and medial thickening, endothelial dysfunction, loss of vascular smooth muscle cells, cellular senescence, extracellular matrix remodeling, and deposition of collagen and calcium. This aging process also leads to overall arterial stiffening and cellular remodeling. The process of genomic instability plays a vital role in accelerating vascular aging. Progeria syndromes, rare genetic disorders causing premature aging, exemplify the impact of genomic instability. Throughout life, our DNA faces constant challenges from environmental radiation, chemicals, and endogenous metabolic products, leading to DNA damage and genome instability as we age. The accumulation of unrepaired damages over time manifests as an aging phenotype. To study vascular aging, various models are available, ranging from in vivo mouse studies to cell culture options, and there are also microfluidic in vitro model systems known as vessels-on-a-chip. Together, these models offer valuable insights into the aging process of blood vessels.

Progress on Physical Field-Regulated Micro/Nanomotors for Cardiovascular and Cerebrovascular Disease Treatment

Cardiovascular and cerebrovascular diseases (CCVDs) are two major vasculature-related diseases that seriously affect public health worldwide, which can cause serious death and disability. Lack of targeting effect of the traditional CCVD treatment drugs may damage other tissues and organs, thus more specific methods are needed to solve this dilemma. Micro/nanomotors are new materials that can convert external energy into driving force for autonomous movement, which can not only enhance the penetration depth and retention rates, but also increase the contact areas with the lesion sites (such as thrombus and inflammation sites of blood vessels). Physical field-regulated micro/nanomotors using the physical energy sources with deep tissue penetration and controllable performance, such as magnetic field, light, and ultrasound, etc. are considered as the emerging patient-friendly and effective therapeutic tools to overcome the limitations of conventional CCVD treatments. Recent efforts have suggested that physical field-regulated micro/nanomotors on CCVD treatments could simultaneously provide efficient therapeutic effect and intelligent control. In this review, various physical field-driven micro/nanomotors are mainly introduced and their latest advances for CCVDs are highlighted. Last, the remaining challenges and future perspectives regarding the physical field-regulated micro/nanomotors for CCVD treatments are discussed and outlined.