Instability in Computational Models of Vascular Smooth Muscle Cell Contraction.

PURPOSE: Through their contractile and synthetic capacity, vascular smooth muscle cells (VSMCs) can regulate the stiffness and resistance of the circulation. To model the contraction of blood vessels, an active stress component can be added to the (passive) Cauchy stress tensor. Different constitutive formulations have been proposed to describe this active stress component. Notably, however, measuring biomechanical behaviour of contracted blood vessels ex vivo presents several experimental challenges, which complicate the acquisition of comprehensive datasets to inform complex active stress models. In this work, we examine formulations for use with limited experimental contraction data as well as those developed to capture more comprehensive datasets. METHODS: First, we prove analytically that a subset of constitutive active stress formulations exhibits unstable behaviours (i.e., a non-unique diameter solution for a given pressure) in certain parameter ranges, particularly for large contractile deformations. Second, using experimental literature data, we present two case studies where these formulations are used to capture the contractile response of VSMCs in the presence of (1) limited and (2) extensive contraction data. RESULTS: We show how limited contraction data complicates selecting an appropriate active stress model for vascular applications, potentially resulting in unrealistic modelled behaviours. CONCLUSION: Our data provide a useful reference for selecting an active stress model which balances the trade-off between accuracy and available biomechanical information. Whilst complex physiologically motivated models' superior accuracy is recommended whenever active biomechanics can be extensively characterised experimentally, a constant 2nd Piola-Kirchhoff active stress model balances well accuracy and applicability with sparse contractile data.

Ligustrazine alleviates the progression of coronary artery calcification by inhibiting caspase-3/GSDME mediated pyroptosis.

Coronary artery calcification (CAC) is an early marker for atherosclerosis and is mainly induced by the osteoblast-like phenotype conversion of vascular smooth muscle cells (VSMCs). Recent reports indicate that NOD-like receptor protein 3 (NLRP3)-mediated pyroptosis plays a significant role in the calcification of vascular smooth muscle cells (VSMCs), making it a promising target for treating calcific aortic valve disease (CAC). Ligustrazine, or tetramethylpyrazine (TMP), has been found effective in various cardiovascular and cerebrovascular diseases and is suggested to inhibit NLRP3-mediated pyroptosis. However, the function of TMP in CAC is unknown. Herein, influences of TMP on ß-glycerophosphate (ß-GP)-stimulated VSMCs and OPG-/- mice were explored. Mouse Aortic Vascular Smooth Muscle (MOVAS-1) cells were stimulated by ß-GP with si- caspase-3, si- Gasdermin E (GSDME) or TMP. Increased calcification, reactive oxygen species (ROS) level, Interleukin-1beta (IL-1ß) and Interleukin-18 (IL-18) levels, lactate dehydrogenase (LDH) release, enhanced apoptosis, and activated cysteine-aspartic acid protease-3 (caspase-3)/GSDME signaling were observed in ß-GP-stimulated MOVAS-1 cells, which was sharply alleviated by si-caspase-3, si-GSDME or TMP. Furthermore, the impact of TMP on the ß-GP-induced calcification and injury in MOVAS-1 cells was abolished by raptinal, an activator of caspase-3. Subsequently, OPG-/- mice were dosed with TMP or TMP combined with raptinal. Calcium deposition, increased nodules, elevated IL-1ß and IL-18 levels, upregulated CASP3 and actin alpha 2, smooth muscle (ACTA2), and activated caspase-3/GSDME signaling in OPG-/- mice were markedly alleviated by TMP, which were notably reversed by the co-administration of raptinal. Collectively, TMP mitigated CAC by inhibiting caspase-3/GSDME mediated pyroptosis.

Zinc Action in Vascular Calcification.

Although zinc's involvement in bone calcification is well-established, its role in vascular calcification, characterized by abnormal calcium and phosphorus deposition in soft tissues and a key aspect of various vascular diseases, including atherosclerosis, remains unclear. This review focuses on zinc's action in vascular smooth muscle cell (VSMC) calcification, including the vascular calcification mechanism. Accumulated research has indicated that zinc deficiency induces calcification in VSMCs and the aorta, primarily through apoptosis accompanied by a downregulation of smooth muscle cell markers. Moreover, zinc deficiency-induced vascular calcification operates independently of the action of alkaline phosphatase (ALP) activity, typically associated with osteogenic processes, but is partly regulated via inorganic phosphate transporter-1 (Pit-1). To date, research has shown that zinc regulates vascular calcification through a mechanism distinct from that of osteogenic calcification, providing insight into its dual effects on physiological and pathological calcification and thereby explaining the "zinc paradox," wherein zinc simultaneously increases osteoblastic calcification and decreases VSMC calcification.

Yohimbine Inhibits PDGF-Induced Vascular Smooth Muscle Cell Proliferation and Migration via FOXO3a Factor.

Yohimbine (YHB) has been reported to possess anti-inflammatory, anticancer, and cardiac function-enhancing properties. Additionally, it has been reported to inhibit the proliferation, migration, and neointimal formation of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor (PDGF) stimulation by suppressing the phospholipase C-gamma 1 pathway. However, the transcriptional regulatory mechanism of YHB controlling the behavior of VSMCs is not fully understood. In this study, YHB downregulated the expression of cell cycle regulatory proteins, such as proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin-dependent kinase 4 (CDK4), and cyclin E, by modulating the transcription factor FOXO3a in VSMCs induced by PDGF. Furthermore, YHB decreased p-38 and mTOR phosphorylation in a dose-dependent manner. Notably, YHB significantly reduced the phosphorylation at Y397 and Y925 sites of focal adhesion kinase (FAK), and this effect was greater at the Y925 site than Y397. In addition, the expression of paxillin, a FAK-associated protein known to bind to the Y925 site of FAK, was significantly reduced by YHB treatment in a dose-dependent manner. A pronounced reduction in the migration and proliferation of VSMCs was observed following co-treatment of YHB with mTOR or p38 inhibitors. In conclusion, this study shows that YHB inhibits the PDGF-induced proliferation and migration of VSMCs by regulating the transcription factor FOXO3a and the mTOR/p38/FAK signaling pathway. Therefore, YHB may be a potential therapeutic candidate for preventing and treating cardiovascular diseases such as atherosclerosis and vascular restenosis.

Two methods of isolation of rat aortic smooth muscle cells with high yield.

Vascular smooth muscle cells (VSMCs) are an integral part of blood vessels and are the focus of intensive research in vascular biology, translational research, and cardiovascular diseases. Though immortalized vascular smooth muscle cell lines are available, their use is limited, underscoring the need for primary VSMCs. There are several methods for isolating primary cells from mice. However, the isolation method from rat blood vessels requires optimization, given the differences in the aorta of mice and rats. Here we compare two methods for VSMCs isolation from rats: enzymatic digestion and the "block" method. We observed a significantly higher yield of VSMCs using the enzymatic digestion method. We further confirmed that VSMCs expressed well-established VSMC-specific markers (calponin) with both methods and observed the persistence of this marker up to 9 passages, suggesting a continuation of the secretory phenotype of VSMCs. Overall, this work compares two methods and demonstrates a practical and effective method for isolating VSMCs from rat aorta, providing vascular biologists with a valuable and reliable experimental tool.

Role of EZH2-mediated epigenetic modification on vascular smooth muscle in cardiovascular diseases: A mini-review.

Vascular smooth muscle cells (VSMCs) are integral to the pathophysiology of cardiovascular diseases (CVDs). Enhancer of zeste homolog 2 (EZH2), a histone methyltransferase, plays a crucial role in epigenetic regulation of VSMCs gene expression. Emerging researches suggest that EZH2 has a dual role in VSMCs, contingent on the pathological context of specific CVDs. This mini-review synthesizes the current knowledge on the mechanisms by which EZH2 regulates VSMC proliferation, migration and survival in the context of CVDs. The goal is to underscore the potential of EZH2 as a therapeutic target for CVDs treatment. Modulating EZH2 and its associated epigenetic pathways in VSMCs could potentially ameliorate vascular remodeling, a key factor in the progression of many CVDs. Despite the promising outlook, further investigation is warranted to elucidate the epigenetic mechanisms mediated by EZH2 in VSMCs, which may pave the way for novel epigenetic therapies for conditions such as atherosclerosis and hypertension.

Inhibition of Vascular Smooth Muscle Cell Proliferation by ENPP1: The Role of CD73 and the Adenosine Signaling Axis.

The Ectonucleotide Pyrophosphatase/Phosphodiesterase 1 (ENPP1) ectoenzyme regulates vascular intimal proliferation and mineralization of bone and soft tissues. ENPP1 variants cause Generalized Arterial Calcification of Infancy (GACI), a rare genetic disorder characterized by ectopic calcification, intimal proliferation, and stenosis of large- and medium-sized arteries. ENPP1 hydrolyzes extracellular ATP to pyrophosphate (PPi) and AMP. AMP is the precursor of adenosine, which has been implicated in the control of neointimal formation. Herein, we demonstrate that an ENPP1-Fc recombinant therapeutic inhibits proliferation of vascular smooth muscle cells (VSMCs) in vitro and in vivo. Addition of ENPP1 and ATP to cultured VSMCs generated AMP, which was metabolized to adenosine. It also significantly decreased cell proliferation. AMP or adenosine alone inhibited VSMC growth. Inhibition of ecto-5'-nucleotidase CD73 decreased adenosine accumulation and suppressed the anti-proliferative effects of ENPP1/ATP. Addition of AMP increased cAMP synthesis and phosphorylation of VASP at Ser157. This AMP-mediated cAMP increase was abrogated by CD73 inhibitors or by A2aR and A2bR antagonists. Ligation of the carotid artery promoted neointimal hyperplasia in wild-type mice, which was exacerbated in ENPP1-deficient ttw/ttw mice. Prophylactic or therapeutic treatments with ENPP1 significantly reduced intimal hyperplasia not only in ttw/ttw but also in wild-type mice. These findings provide the first insight into the mechanism of the anti-proliferative effect of ENPP1 and broaden its potential therapeutic applications beyond enzyme replacement therapy.

Selective mural cell recruitment of pericytes to networks of assembling endothelial cell-lined tubes.

Mural cells are critically important for the development, maturation, and maintenance of the blood vasculature. Pericytes are predominantly observed in capillaries and venules, while vascular smooth muscle cells (VSMCs) are found in arterioles, arteries, and veins. In this study, we have investigated functional differences between human pericytes and human coronary artery smooth muscle cells (CASMCs) as a model VSMC type. We compared the ability of these two mural cells to invade three-dimensional (3D) collagen matrices, recruit to developing human endothelial cell (EC)-lined tubes in 3D matrices and induce vascular basement membrane matrix assembly around these tubes. Here, we show that pericytes selectively invade, recruit, and induce basement membrane deposition on EC tubes under defined conditions, while CASMCs fail to respond equivalently. Pericytes dramatically invade 3D collagen matrices in response to the EC-derived factors, platelet-derived growth factor (PDGF)-BB, PDGF-DD, and endothelin-1, while minimal invasion occurs with CASMCs. Furthermore, pericytes recruit to EC tube networks, and induce basement membrane deposition around assembling EC tubes (narrow and elongated tubes) when these cells are co-cultured. In contrast, CASMCs are markedly less able to perform these functions showing minimal recruitment, little to no basement membrane deposition, with wider and shorter tubes. Our new findings suggest that pericytes demonstrate much greater functional ability to invade 3D matrix environments, recruit to EC-lined tubes and induce vascular basement membrane matrix deposition in response to and in conjunction with ECs.

The molecular and cellular hematopoietic stem cell specification niche.

Hematopoietic stem cells (HSCs) are a population of tissue-specific stem cells that reside in the bone marrow of adult mammals where they self-renew and continuously regenerate the adult hematopoietic lineages over the life of the individual. Prominence as a stem cell model and clinical usefulness has driven interest in understanding the physiological processes that lead to specification of HSCs during embryonic development. High efficiency directed differentiation of HSCs by instruction of defined progenitor cells using sequentially defined instructive molecules and conditions remains impossible, indicating that comprehensive knowledge of the complete set of precursor intermediate identities and required inductive inputs remains incompletely understood. Recently, interest in the molecular and cellular microenvironment where HSCs are specified from endothelial precursors-the "specification niche"-has increased. Here we review recent progress in understanding these niche spaces across vertebrate phyla, as well as how a better characterization of the origin and molecular phenotypes of the niche cell populations has helped inform and complicate previous understanding of signaling required for HSC emergence and maturation.

Inhibition effect of copper-bearing metals on arterial neointimal hyperplasia via the AKT/Nrf2/ARE pathway in vitro and in vivo.

In-stent restenosis can be caused by the activation, proliferation and migration of vascular smooth muscle cells (VSMCs), which affects long-term efficacy of interventional therapy. Copper (Cu) has been proved to accelerate the endothelialization and reduce thrombosis formation, but little is known about its inhibition effect on the excessive proliferation of VSMCs. In this study, 316L-Cu stainless steel and L605-Cu cobalt-based alloy with varying Cu content were fabricated and their effects on surface property, blood compatibility and VSMCs were studied in vitro and in vivo. CCK-8 assay and EdU assay indicated that the Cu-bearing metals had obvious inhibitory effect on proliferation of VSMCs. Blood clotting and hemolysis tests showed that the Cu-bearing metals had good blood compatibility. The inhibition effect of the Cu-bearing metals on migration of cells was detected by Transwell assay. Further studies showed that Cu-bearing metals significantly decreased the mRNA expressions of bFGF, PDGF-B, HGF, Nrf2, GCLC, GCLM, NQO1 and HO1. The phosphorylation of AKT and Nrf2 protein expressions in VSMCs were significantly decreased by Cu-bearing metals. Furthermore, it was also found that SC79 and TBHQ treatments could recover the protein expressions of phospho-AKT and Nrf2, and their downstream proteins as well. Moreover, 316L-Cu stent proved its inhibitory action on the proliferation of VSMCs in vivo. In sum, the results demonstrated that the Cu-bearing metals possessed apparent inhibitory effect on proliferation and migration of VSMCs via regulating the AKT/Nrf2/ARE pathway, showing the Cu-bearing metals as promising stent materials for long-term efficacy of implantation.

Role of transient receptor potential channels in the regulation of vascular tone.

Vascular tone is a major element in the control of hemodynamics. Transient receptor potential (TRP) channels conducting monovalent and/or divalent cations (e.g. Na+ and Ca2+) are expressed in the vasculature. Accumulating evidence suggests that TRP channels participate in regulating vascular tone by regulating intracellular Ca2+ signaling in both vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Aberrant expression/function of TRP channels in the vasculature is associated with vascular dysfunction in systemic/pulmonary hypertension and metabolic syndromes. This review intends to summarize our current knowledge of TRP-mediated regulation of vascular tone in both physiological and pathophysiological conditions and to discuss potential therapeutic approaches to tackle abnormal vascular tone due to TRP dysfunction.

A CEBPB/miR-32-5p/GATA6 axis promotes vascular calcification in type 2 diabetes.

Vascular calcification in diabetes patients is a major independent risk factor for developing diabetic cardiovascular complications. However, the mechanisms by which diabetes leads to vascular calcification are complex and not yet fully understood. Our previous study revealed that miR-32-5p is a potential new diagnostic marker for coronary artery calcification. In this study, we found that miR-32-5p levels were significantly greater in the plasma of type 2 diabetes patients with coronary artery calcification and were positively correlated with the coronary artery calcification score. In type 2 diabetic mice, miR-32-5p levels were also elevated in the aorta, and knockout of miR-32-5p inhibited the osteogenic differentiation of vascular smooth muscle cells in vivo. Furthermore, overexpression of miR-32-5p promoted vascular smooth muscle cell calcification, while antagonism of miR-32-5p inhibited vascular smooth muscle cell calcification under high-glucose conditions. GATA binding protein 6 (GATA6) was identified as the key target gene through which miR-32-5p promotes vascular smooth muscle cell calcification. Overexpression of GATA6 antagonized the effects of miR-32-5p on vascular calcification. Additionally, high glucose levels were shown to induce the upregulation of miR-32-5p by activating CCAAT/enhancer binding protein beta (CEBPB). These results suggest that miR-32-5p is an important procalcification factor in vascular calcification associated with type 2 diabetes and identify the CEBPB/miR-32-5p/GATA6 axis as a potential biomarker and therapeutic target for preventing and treating vascular calcification in type 2 diabetes.

Suppression of neointimal hyperplasia induced by arteriovenous anastomosis and balloon injury in rats by multimeric tumor necrosis factor-related apoptosis-inducing ligand.

Excessive blood vessel wall thickening, known as intimal hyperplasia, can result from injury or inflammation and increase the risk of vascular diseases. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) plays key roles in tumor surveillance, autoimmune diseases, and apoptosis; however, its role in vascular stenosis remains controversial. Treatment with recombinant isoleucine zipper hexamerization domain soluble TRAIL (ILz(6):TRAIL) significantly inhibited the progression of neointimal hyperplasia (NH) induced by anastomosis of the carotid artery and jugular vein dose dependently, and adenovirus expressing secretable ILz(6):TRAIL also inhibited NH induced by balloon injury in the femoral artery of rats. This study demonstrated the preventive and partial regressive effects of ILz(6):TRAIL on anastomosis of the carotid artery and jugular vein- or balloon-induced NH.

High estrogen induces trans-differentiation of vascular smooth muscle cells to a macrophage-like phenotype resulting in aortic inflammation via inhibiting VHL/HIF1a/KLF4 axis.

Estrogen is thought to have a role in slowing down aging and protecting cardiovascular and cognitive function. However, high doses of estrogen are still positively associated with autoimmune diseases and tumors with systemic inflammation. First, we administered exogenous estrogen to female mice for three consecutive months and found that the aorta of mice on estrogen develops inflammatory manifestations similar to Takayasu arteritis (TAK). Then, in vitro estrogen intervention was performed on mouse aortic vascular smooth muscle cells (MOVAS cells). Stimulated by high concentrations of estradiol, MOVAS cells showed decreased expression of contractile phenotypic markers and increased expression of macrophage-like phenotypic markers. This shift was blocked by tamoxifen and Krüppel-like factor 4 (KLF4) inhibitors and enhanced by Von Hippel-Lindau (VHL)/hypoxia-inducible factor-1α (HIF-1α) interaction inhibitors. It suggests that estrogen-targeted regulation of the VHL/HIF-1α/KLF4 axis induces phenotypic transformation of vascular smooth muscle cells (VSMC). In addition, estrogen-regulated phenotypic conversion of VSMC to macrophages is a key mechanism of estrogen-induced vascular inflammation, which justifies the risk of clinical use of estrogen replacement therapy.

Proximity Labelling to Quantify Kv7.4 and Dynein Protein Interaction in Freshly Isolated Rat Vascular Smooth Muscle Cells.

Understanding protein-protein interactions is crucial for unravelling subcellular protein distribution, contributing to our understanding of cellular organisation. Moreover, interaction studies can reveal insights into the mechanisms that cover protein trafficking within cells. Although various techniques such as Förster resonance energy transfer (FRET), co-immunoprecipitation, and fluorescence microscopy are commonly employed to detect protein interactions, their limitations have led to more advanced techniques such as the in situ proximity ligation assay (PLA) for spatial co-localisation analysis. The PLA technique, specifically employed in fixed cells and tissues, utilises species-specific secondary PLA probes linked to DNA oligonucleotides. When proteins are within 40 nm of each other, the DNA oligonucleotides on the probes interact, facilitating circular DNA formation through ligation. Rolling-circle amplification then produces DNA circles linked to the PLA probe. Fluorescently labelled oligonucleotides hybridise to the circles, generating detectable signals for precise co-localisation analysis. We employed PLA to examine the co-localisation of dynein with the Kv7.4 channel protein in isolated vascular smooth muscle cells from rat mesenteric arteries. This method enabled us to investigate whether Kv7.4 channels interact with dynein, thereby providing evidence of their retrograde transport by the microtubule network. Our findings illustrate that PLA is a valuable tool for studying potential novel protein interactions with dynein, and the quantifiable approach offers insights into whether these interactions are changed in disease.

PCSK9 expression in fibrous cap possesses a marker for rupture in advanced plaque.

BACKGROUND: To date, PCSK9 inhibitors are well known for eliminating cardiac and cerebral artery ischemia events by lowering the serum lipid level. However, the pathophysiological value of in-plaque PCSK9 expression is still unclear. METHODS: Advanced plaques removed by carotid endarterectomy were sectioned and stained to identify the PCSK9 expression pattern and its co-expression with rupture-relevant markers. To investigate the correlation of PCSK9 expression with regional blood shear flow, hemodynamic characteristics were analyzed using computational fluid dynamics, and representative parameters were compared between PCSK9 positive and negative staining plaques. To explore this phenomenon in vitro, human aortic vascular smooth muscle cells were used to overexpress and knock down PCSK9. The impacts of PCSK9 modulations on mechanical sensor activity were testified by western blot and immunofluorescence. Real-time polymerase chain reaction was used to evaluate the transcription levels of downstream rupture-prone effectors. RESULTS: PCSK9 distribution in plaque preferred cap and shoulder regions, residing predominantly in smooth muscle actin-positive cells. Cap PCSK9 expression correlated with fibrous cap thickness negatively and co-expressed with MMP-9, both pointing to the direction of plaque rupture. A hemodynamic profile indicated a rupture-prone feature of cap PCSK9 expression. In vitro, overexpression and knockdown of PCSK9 in human aortic vascular smooth muscle cells has positive modulation on mechanical sensor Yes-associated protein 1 (YAP) activity and transcription levels of its downstream rupture-prone effectors. Serial section staining verified in situ colocalization among PCSK9, YAP, and downstream effectors. CONCLUSIONS: Cap PCSK9 possesses a biomarker for rupture risk, and its modulation may lead to a novel biomechanical angle for plaque interventions.

Fibronectin/α5 Integrin Contribute to Hypertension-Associated Arterial Ageing and Calcification through Affecting BMP2/MGP Imbalance and Enhancing Vascular Smooth Muscle Cell Phenotypic Transformation.

INTRODUCTION: Hypertension can accelerate and aggravate the process of arterial ageing and calcification. However, the mechanism behind has yet to be well elucidated. METHODS: Here, we monitored the dynamic changes of fibronectin (FN)/α5 integrin, bone morphogenetic protein 2/matrix Gla protein (BMP2/MGP), and Runx2 in the aorta of spontaneously hypertensive rats (SHRs) and thoracic aortic vascular smooth muscle cells (VSMCs), also the phenotypic transformation of VSMCs during the process of arterial ageing and calcification. Further, study on arterial ageing and calcification through antagonist experiments at the molecular level was explored. RESULTS: We found extracellular FN and its α5 integrin receptor expressions were positively associated with arterial ageing and calcification in SHR during ageing, as well in VSMCs from SHR in vitro. Integrin receptor inhibitor of GRGDSP would delay this arterial ageing and calcification process. Moreover, the elevated FN and α5 integrin receptor expression evoked the disequilibrium of BMP2/MGP, where the expression of BMP2, a potent osteogenic inducer, increased while MGP, a calcification inhibitor, decreased. Furthermore, it was followed by the upregulation of Runx2 and the phenotypic transformation of VSMCs from the contractile phenotype into the osteoblast-like cells. Notably, BMP2 antagonist of rmNoggin was sufficient to ameliorate the ageing and calcification process of VSMCs and exogenous BMP2-adding accelerate and aggregate the process. CONCLUSION: Our study revealed that hypertension-associated arterial ageing and calcification might be a consequence that hypertension up-regulated FN and its high binding affinity integrin α5 receptor in the aortic wall, which in turn aggravated the imbalance of BMP2/MGP, promoted the transcription of Runx2, and induced the phenotypic transformation of VSMCs from the contractile phenotype into the osteoblast-like cells. Our study would provide insights into hypertension-associated arterial ageing and calcification and shed new light on the control of arterial calcification, especially for those with hypertension.

Human Genetics of Semilunar Valve and Aortic Arch Anomalies.

Lesions of the semilunar valve and the aortic arch can occur either in isolation or as part of well-described clinical syndromes. The polygenic cause of calcific aortic valve disease will be discussed including the key role of NOTCH1 mutations. In addition, the complex trait of bicuspid aortic valve disease will be outlined, both in sporadic/familial cases and in the context of associated syndromes, such as Alagille, Williams, and Kabuki syndromes. Aortic arch abnormalities particularly coarctation of the aorta and interrupted aortic arch, including their association with syndromes such as Turner and 22q11 deletion, respectively, are also discussed. Finally, the genetic basis of congenital pulmonary valve stenosis is summarized, with particular note to Ras-/mitogen-activated protein kinase (Ras/MAPK) pathway syndromes and other less common associations, such as Holt-Oram syndrome.

Dynamin-related protein 1 mediates the therapeutic effect of isoliquiritigenin in diabetic intimal hyperplasia via regulation of mitochondrial fission.

Phenotypic shift of vascular smooth muscle cells (VSMCs) plays a key role in intimal hyperplasia, especially in patients with diabetes mellitus (DM). This study aimed to investigate the role of dynamin-related protein 1 (DRP1) in mitochondrial fission-mediated VSMC phenotypic shift and to clarify whether DRP1 is the therapeutic target of isoliquiritigenin (ISL). Wire injury of carotid artery or platelet-derived growth factor treatment was performed in DM mice or high-glucose cultured human aortic smooth muscle cells (HASMCs), respectively. The effects of DRP1 silencing on DM-induced intimal hyperplasia were investigated both in vivo and in vitro. Phenotypic shift of HASMCs was evaluated by detection of reactive oxygen species (ROS) generation, cell viability, and related protein expressions. The effects of ISL on DM-induced intimal hyperplasia were evaluated both in vivo and in vitro. DRP1 silencing and ISL treatment attenuated DM-induced intimal hyperplasia with reduced ROS generation, cell viability, and VSMC dedifferentiation. The GTPase domain of DRP1 protein played a critical role in mitochondrial fission in DM-induced VSMC phenotypic shift. Cellular experiments showed that ISL inhibited mitochondrial fission and reduced the GTPase activity of DRP1, which was achieved by the directly binding to K216 of the DRP1 GTPase domain. ISL attenuated mouse intimal hyperplasia by reducing GTPase activity of DRP1 and inhibiting mitochondrial fission in vivo. In conclusion, increased GTPase activity of DRP1 aggregated DM-induced intimal hyperplasia by increasing mitochondrial fission-mediated VSMC phenotypic shift. ISL attenuated mouse intimal hyperplasia by reducing DRP1 GTPase activity and inhibiting mitochondrial fission of VSMCs.

SIRT-associated attenuation of cellular senescence in vascular wall.

This review focuses on the vital function that SIRT1 and other sirtuins play in promoting cellular senescence in vascular smooth muscle cells, which is a key element in the pathogenesis of vascular aging and associated cardiovascular diseases. Vascular aging is a gradual process caused by the accumulation of senescent cells, which results in increased vascular remodeling, stiffness, and diminished angiogenic ability. Such physiological alterations are characterized by a complex interplay of environmental and genetic variables, including oxidative stress and telomere attrition, which affect gene expression patterns and trigger cell growth arrest. SIRT1 has been highlighted for its potential to reduce cellular senescence through modulation of multiple signaling cascades, particularly the endothelial nitric oxide (eNOS)/NO signaling pathway. It also modulates cell cycle through p53 inactivation and suppresses NF-κB mediated expression of adhesive molecules at the vascular level. The study also examines the therapeutic potential of sirtuin modulation in vascular health, identifying SIRT1 and its sirtuin counterparts as potential targets for reducing vascular aging. This study sheds light on the molecular basis of vascular aging and the beneficial effects of sirtuins, paving the way for the development of tailored therapies aimed at enhancing vascular health and prolonging life.