Smooth Muscle Research Articles

Three-dimensional ultrastructural analysis of human skin with the arrector pili muscle interacting with the hair follicle epithelium.

This study developed a three-dimensional ultrastructural analysis application using serial block-face scanning electron microscopy (SBF-SEM) to investigate surgically acquired human skin tissues containing the arrector pili muscle. We utilized the en bloc staining, including reduced osmium, thiocarbohydrazide, and lead aspartate, as well as the embedding using a carbon-based conductive resin. Next, we obtained serial images with SBF-SEM. The results revealed dense nerve fiber networks branching from nearby nerve fiber bundles outside the muscle and running among muscle fibers. Additionally, the dense nerve network running through and along arrector pili muscle fibers rarely penetrates the connective tissues between smooth muscle fibers and epithelial cells. Furthermore, in the observation area, no individual smooth muscle fibers formed adhesion structures with the epithelial cells of the hair follicle, ending in the dermal extracellular matrix near the epithelial cells. These results indicate the usefulness of this approach for three-dimensional ultrastructural analyses of human skin tissues comprising follicular units and revealing structural changes in skin tissues, especially the arrector pili muscle and nerve fibers with hair follicular epithelium, in aging and diseased conditions.

Riding a Vascular Time Train to Spatiotemporally Attenuate Thrombosis and Restenosis by Double Presentation of Therapeutic Gas and Biomacromolecules

ABSTRACTEndothelial injury is a common occurrence following stent implantation, often leading to complications such as restenosis and thrombosis. To address this issue, we have developed a multi‐functional stent coating that combines a dopamine‐copper (DA‐Cu) base with therapeutic biomolecule modification, including nitric oxide (NO) precursor L‐arginine, endothelial glycocalyx heparin, and endothelial cell (EC) catcher vascular endothelial growth factor (VEGF). In our stent coating, the incorporated Cu acts as a sustainable catalyst for converting endogenous NO donors into NO, and the immobilized arginine serves as a precursor for NO generation under the effect of endothelial nitric oxide synthase (eNOS). The presence of heparin endows the stent coating with anticoagulant ability and enhances eNOS activity, whilst rapid capture of EC by VEGF accelerates re‐endothelialization. After in vivo implantation, the antioxidant elements and produced NO alleviate the inflammatory response, establishing a favorable healing environment. The conjugated VEGF contributes to the formation of a new and intact endothelium on the stent surface to counteract inappropriate vascular cell behaviors. The long‐lasting NO flux inhibits smooth muscle cell (SMC) migration and prevents its excessive proliferation, reducing the risk of endothelial hyperplasia. This innovative coating enables the dual delivery of VEGF and NO to target procedural vascular repair phases: promoting rapid re‐endothelialization, effectively preventing thrombosis, and suppressing inflammation and restenosis. Ultimately, this innovative coating has the potential to improve therapeutic outcomes following stent implantation.

Targeting fibroblast-endothelial interactions in LAM pathogenesis using 3D spheroid models and spatial transcriptomics.

Lymphangioleiomyomatosis (LAM) is a progressive lung disease with limited treatments, largely due to an incomplete understanding of its pathogenesis. Lymphatic endothelial cells (LECs) invade LAM cell clusters, which include HMB-45-positive epithelioid cells and smooth muscle α-actin-expressing LAM-associated fibroblasts (LAMFs). Recent evidence shows that LAMFs resemble cancer-associated fibroblasts, with LAMF-LEC interactions contributing to disease progression. To explore these mechanisms, we used spatial transcriptomics on LAM lung tissues and identified a gene cluster enriched in kinase signaling pathways linked to myofibroblasts and co-expressed with LEC markers. Kinase arrays revealed elevated PDGFR and FGFR in LAMFs. Using a 3D co-culture spheroid model of primary LAMFs and LECs, we observed increased invasion in LAMF-LEC spheroids compared to non-LAM fibroblasts. Treatment with sorafenib, a multikinase inhibitor, significantly reduced invasion, outperforming Rapamycin. We also confirmed TSC2-deficient renal angiomyolipoma cells (TSC2-null AML) as key VEGF-A secretors, which was suppressed by sorafenib in both TSC2-null AML cells and LAMFs. These findings highlight VEGF-A and bFGF as potential therapeutic targets and suggest multikinase inhibition as a promising strategy for LAM.

BCL6 (B-cell lymphoma 6) expression in adenomyosis, leiomyomas and normal myometrium.

Adenomyosis and leiomyomas are common benign uterine disorders characterized by abnormal cellular proliferation. The BCL6 protein, a transcriptional repressor implicated in cell proliferation and oncogenesis, has been linked to the pathogenesis of endometriosis. This study investigates BCL6 expression in adenomyosis, leiomyomas, and normal myometrium using immunohistochemistry and deep learning neural networks. We analyzed paraffin blocks from total hysterectomies performed between 2009 and 2017, confirming diagnoses through pathological review. Immunohistochemistry was conducted using an automated system, and BCL6 expression was quantified using Fiji-ImageJ software. A supervised deep learning neural network was employed to classify samples based on DAB staining. Our results show that BCL6 expression is significantly higher in leiomyomas compared to adenomyosis and normal myometrium. No significant difference in BCL6 expression was observed between adenomyosis and controls. The deep learning neural network accurately classified samples with a high degree of precision, supporting the immunohistochemical findings. These findings suggest that BCL6 plays a role in the pathogenesis of leiomyomas, potentially contributing to abnormal smooth muscle cell proliferation. The study highlights the utility of automated immunohistochemistry and deep learning techniques in quantifying protein expression and classifying uterine pathologies. Future studies should investigate the expression of BCL6 in adenomyosis and endometriosis to further elucidate its role in uterine disorders.

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.

Inhibition of soluble epoxide hydrolase ameliorates cerebral blood flow autoregulation and cognition in alzheimer's disease and diabetes-related dementia rat models.

Alzheimer's Disease and Alzheimer's Disease-related dementias (AD/ADRD) pose major global healthcare challenges, with diabetes mellitus (DM) being a key risk factor. Both AD and DM-related ADRD are characterized by reduced cerebral blood flow, although the exact mechanisms remain unclear. We previously identified compromised cerebral hemodynamics as early signs in TgF344-AD and type 2 DM-ADRD (T2DN) rat models. Genome-wide studies have linked AD/ADRD to SNPs in soluble epoxide hydrolase (sEH). This study explored the effects of sEH inhibition with TPPU on cerebral vascular function and cognition in AD and DM-ADRD models. Chronic TPPU treatment improved cognition in both AD and DM-ADRD rats without affecting body weight. In DM-ADRD rats, TPPU reduced plasma glucose and HbA1c levels. Transcriptomic analysis of primary cerebral vascular smooth muscle cells from AD rats treated with TPPU revealed enhanced pathways related to cell contraction, alongside decreased oxidative stress and inflammation. Both AD and DM-ADRD rats exhibited impaired myogenic responses and autoregulation in the cerebral circulation, which were normalized with chronic sEH inhibition. Additionally, TPPU improved acetylcholine-induced vasodilation in the middle cerebral arteries (MCA) of DM-ADRD rats. Acute TPPU administration unexpectedly caused vasoconstriction in the MCA of DM-ADRD rats at lower doses. In contrast, higher doses or longer durations were required to induce effective vasodilation at physiological perfusion pressure in both control and ADRD rats. Additionally, TPPU decreased reactive oxygen species production in cerebral vessels of AD and DM-ADRD rats. These findings provide novel evidence that chronic sEH inhibition can reverse cerebrovascular dysfunction and cognitive impairments in AD/ADRD, offering a promising avenue for therapeutic development.

Multi-Scale Multi-Cell Computational Model of Inflammation-Mediated Aortic Remodeling in Hypertension.

Multiple cell types interact within the aortic wall to control development, homeostasis, and adaptation as well as to drive disease progression. Given the complexity of these interactions and their manifestations at the tissue level, there is a pressing need for a new class of computational models that integrate data across scales. We meld logic-based cell signaling models of vascular smooth muscle cells, adventitial fibroblasts, and macrophages and couple this multi-cell model with a tissue level-constrained mixture model of aortic growth and remodeling. The coupled multi-scale model is parameterized using data from the literature and then specialized for the case of angiotensin II-induced hypertensive remodeling of the descending thoracic aorta in wild-type mice. We contrast important contributions of chemo- and mechano-stimulation of cell responses and identify critical roles of recruited macrophages in driving the non-homeostatic thickening of the adventitial layer that reduces biaxial wall stress below setpoint values. We show the utility of a multi-scale, multi-cell model in delineating effects of different chemo-mechanical stimuli in aortic remodeling in hypertension.

Integrated Transcriptomic and Metabolomic Analysis of Rat PASMCs Reveals the Underlying Mechanism for Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a kind of pulmonary vascular lesion characterized by vasoconstriction and reshaping of small pulmonary arteries, ultimately resulting in increased pulmonary artery pressure and pulmonary vascular resistance, and eventually leading to right ventricular failure and death. This study was aimed to construct a platelet-derived growth factor BB (PDGF-BB)-induced rat pulmonary artery smooth muscle cells (PASMCs) model and conduct a combined transcriptomic and metabolomic analysis to identify proliferation-related targets, thereby enhancing understanding of the pathogenesis underlying PAH. Rat PASMCs were isolated and cultured in the presence or absence of PDGF-BB for 24 hours. Cells were collected for transcriptomics and metabolomics investigations. A total of 1288 differentially expressed genes (572 up-regulated and 716 down-regulated) were identified in PDGF-BB-treated rat PASMCs compared to control cells. Subsequently, Gene ontology (GO) enrichment analysis revealed that 791 enriched GO terms were significantly enriched in PDGF-BB treated cells. Similarly, 294 differential metabolic pathways were enriched in PDGF-BB treated cells according to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, Gene Set Enrichment Analysis (GSEA) were performed on the differentially expressed genes (DEGs). It turned out that 7219 gene sets were more enriched in PDGF-BB treated cells. In addition, a total of 28 secondary differential metabolites were identified in PDGF-BB-treated rat PASMCs compared to control cells (p-value < 0.05 and VIP > 1). We speculate that Mylk, Pla2g4a, Gucy1b1, Adcy8, Adcy4, Gucy1a2, Col3a1, and Plcb4 are potential targets for the treatment of PAH.

Prevalence of pulmonary anthracosis in household dogs in southwest states in Nigeria: a sentinel for environmental pollution.

Nigeria, stemming from vehicular traffic, generator sets, industrial sources, residential combustion, and road dust. Pulmonary anthracosis, the accumulation of carbon particles in the lungs, is a known risk factor for cancer. While this condition has been observed in stray dogs, data on its prevalence in household dogs is limited. This study aimed to determine the prevalence of pulmonary anthracosis in household dogs within three southwestern states of Nigeria over a decade (2011-2020) and to analyze the histopathological features of pulmonary anthracosis observed in canine lung tissue samples submitted for post-mortem examination. Lung tissue samples from 472 dog carcasses submitted to the Federal University of Agriculture, Abeokuta, and the University of Ibadan for post-mortem examination were analyzed in this study. Lesions suggestive of pulmonary anthracosis were identified through gross examination and further analyzed histologically to confirm their characteristics. The findings were presented using tables, charts, and chi-square to determine association between breed, age, and sex considering p < 0.05 as significant. Out of total lungs sampled, 150 (31.8%) were positive for pulmonary anthracosis. No significant association was found between breed (p = 0.95) or sex (p = 0.98) and anthracosis, but age was statistically significant (p = 0.01). Histopathological findings included bronchiolar smooth muscle hypertrophy (90%), severe fibrosis (80%), and bronchiolar epithelial hyperplasia (50%). The study concluded that pulmonary anthracosis is prevalent among household dogs in the region. The pathological changes highlighted the adverse effects associated with the condition in affected organs and that black carbon as a major air pollutant that poses health risks to humans and animals.

Quantifying the tumour vasculature environment from CD-31 immunohistochemistry images of breast cancer using deep learning based semantic segmentation

BackgroundTumour vascular density assessed from CD-31 immunohistochemistry (IHC) images has previously been shown to have prognostic value in breast cancer. Current methods to measure vascular density, however, are time-consuming, suffer from high inter-observer variability and are limited in describing the complex tumour vasculature morphometry.MethodsWe propose a method for automatically measuring a range of vascular parameters from CD-31 IHC images, which together provide a detailed description of the vasculature morphology. We first used a U-Net based convolutional neural network, trained and validated using 36 partially annotated whole slide images from 27 patients, to segment vessel structures and tumour regions from which the measurements are taken. The model also segments the vascular smooth muscle, benign epithelium, adipose tissue, stroma, lymphocyte clusters, nerves and CD-31 positive leukocytes, and we applied it to an additional 21 images from 15 patients. Using these segmentations, we investigated the relationship between the various tissue types and the vasculature and studied the relationship of various vascular parameters with clinical parameters. We also performed a 3D histology analysis on a separate tumour sample as a proof of principle, providing a more comprehensive visualization of vasculature morphology compared to the standard 2D cross-section of a tissue sample.ResultsUsing two-way cross-validation, we show that vessels were accurately segmented, with Dice scores of 0.875 and 0.856, and were accurately identified, with F1 scores of 0.777 and 0.748. All vascular parameters exhibit strong (r>0.70.7$$\\end{document}]]>) and significant (p<0.001) correlations with measurements taken from the manual ground truth vessel segmentations. A significant relationship between the major/minor axis ratio, a measure of elongation, and the tumour grade was found.ConclusionOur proposed method shows promise as a tool for studying the tumour vasculature and its relationship with surrounding cells and tissue types. Furthermore, the correlation with tumour grade highlights the clinical relevance of our approach. These findings suggest that our method could have substantial implications for improving prognostic assessments and personalizing therapeutic strategies in breast cancer treatment.

Relaxation of mucosal fibronectin fibers in late gut inflammation following neutrophil infiltration in mice

The continuously remodeled extracellular matrix (ECM) plays a pivotal role in gastrointestinal health and disease, yet its precise functions remain elusive. In this study, we employed laser capture microdissection combined with low-input proteomics to investigate ECM remodeling during Salmonella-driven inflammation. To complement this, we probed how fibronectin fiber tension is altered using a mechanosensitive peptide probe. While fibronectin fibers in healthy intestinal tissue are typically stretched, many lose their tension in intestinal smooth muscles only hours after infection, despite the absence of bacteria in that area. In contrast, within the mucosa, where Salmonella is present starting 12 h post infection, fibronectin fiber relaxation occurred exclusively during late-stage infection at 72 h and was localized to already existing clusters of infiltrated neutrophils. Using N-terminomics, we identified three new cleavage sites in fibronectin in the inflamed cecum. The unique, tissue layer-specific changes in the molecular compositions and ECM fiber tension revealed herein might trigger new therapeutic strategies to fight acute intestinal inflammation.

Cyanidin 3-O-β-d-Glucoside from Black Bean Inhibits the Migration of Vascular Smooth Muscle Cells in the Presence of Adipocytes

Background The potential of cyanidin 3- O-β-D-glucoside (C3G), known for its anti-obesity and anti-diabetic properties, in suppressing arteriosclerosis progression remains unexplored. Purpose This study aimed to elucidate whether C3G prevents or ameliorates arteriosclerosis by investigating the effects of C3G on the transformation, proliferation, and migration of vascular smooth muscle cells (SMCs). Herein, we evaluated the effects of C3G on the migratory ability of SMCs in the presence of adipocytes. Materials and Methods SMCs and 3T3-L1 adipocytes were cocultured in a Boyden chamber, with SMCs positioned in the upper chamber and pre-adipocytes in the lower chamber. Pre-adipocytes were initially seeded in the lower chamber and prompted to undergo differentiation over days 0, 2, 4, 6, and 8. SMCs were seeded in the upper chamber. The quantification of cells that migrated through the membrane was carried out. The migratory potential of SMCs within the SMC/adipocyte coculture (SACC) setup was assessed by placing the upper chamber into wells containing adipocytes, with or without 0.1% C3G. Results The findings indicated that the accumulation of lipid droplets in adipocytes increased as the differentiation stage progressed. The amount of lipid droplets that accumulated upon the addition of C3G was significantly lower than that in the control. C3G was found to inhibit the active form of plasminogen activator inhibitor-1 (PAI-1) while enhancing the levels of the anti-inflammatory adipocytokine adiponectin. In the SACC, SMC migration increased alongside lipid droplet accumulation in adipocytes. We revealed that C3G decreased the active form of PAI-1 in the SACC and suppressed vascular SMC migration. Conclusion C3G inhibited the migration of SMCs in the SACC, highlighting its potential as a compound that can prevent arteriosclerosis and thrombus formation progression by suppressing hyperplasia of the vascular intima.

Proteome-Wide Mendelian Randomization Identifies Therapeutic Targets for Abdominal Aortic Aneurysm.

The proteome is a key source of therapeutic targets. We conducted a comprehensive Mendelian randomization analysis across the proteome to identify potential protein markers and therapeutic targets for abdominal aortic aneurysm (AAA). Our study used plasma proteomics data from the UK Biobank, comprising 2923 proteins from 54 219 individuals, and from deCODE Genetics, which measured 4907 proteins across 35 559 individuals. Significant proteomic quantitative trait loci were used as instruments for Mendelian randomization. Genetic associations with AAA were sourced from the AAAgen consortium, a large-scale genome-wide association study meta-analysis involving 37 214 cases and 1 086 107 controls, and the FinnGen study, which included 3869 cases and 381 977 controls. Sequential analyses of colocalization and summary-data-based Mendelian randomization were performed to verify the causal roles of candidate proteins. Additionally, single-cell expression analysis, protein-protein interaction network analysis, pathway enrichment analysis, and druggability assessments were conducted to identify cell types with enriched expression and prioritize potential therapeutic targets. The proteome-wide Mendelian randomization analysis identified 34 proteins associated with AAA risk. Among them, 2 proteins, COL6A3 and PRKD2, were highlighted by colocalization analysis, summary-data-based Mendelian randomization, and the heterogeneity in an independent instrument test, providing the most convincing evidence. These protein-coding genes are primarily expressed in macrophages, smooth muscle cells, and mast cells within abdominal aortic aneurysm tissue. Several causal proteins are involved in pathways regulating lipid metabolism, immune responses, and extracellular matrix organization. Nine proteins have already been targeted for drug development in diabetes and other cardiovascular diseases, presenting opportunities for repurposing as AAA therapeutic targets. This study identifies causal proteins for AAA, enhancing our understanding of its molecular cause and advancing the development of therapeutics.

Smooth muscle cell Piezo1 is essential for phenotypic switch and neointimal hyperplasia.

Disturbed blood flow is a critical factor in activation of vascular smooth muscle cells (VSMCs) and initiation of neointimal hyperplasia. The Piezo1 channel is a recent yet well-characterised mechanosensor that plays a vital role in vascular development and homeostasis. However, the role of VSMC Piezo1 in neointima development remains largely unknown. The purpose of this study is to investigate the functional role of Piezo1 channel in neointimal hyperplasia. We measured the expression of Piezo1 in VSMC-rich neointima from human coronary artery samples and two mouse neointimal hyperplasia models which were induced by cast implantation or guidewire injury. We utilised VSMC-specific Piezo1 knockout mice to explore its function and the underlying mechanism of neointimal hyperplasia, both in vivo and in vitro. In human and mouse neointima samples, we observed a significant up-regulation of Piezo1 expression in the VSMC-rich neointima compared to the medial layer. VSMC-specific knockout of Piezo1 significantly reduced neointimal hyperplasia in both animal models. Activation of Piezo1 facilitates, whereas Piezo1 deficiency inhibits disturbed flow-induced cell proliferation, migration and synthetic phenotype switch. Mechanistic studies suggest that Piezo1 activates YAP and TAZ through Ca2+ and its downstream effectors calmodulin kinase II and calcineurin, which in turn drive VSMC proliferation and migration, thereby facilitating neointimal hyperplasia. These findings demonstrate a critical role of mechanosensitive Piezo1 channel in neointimal hyperplasia via modulating VSMC phenotype. Piezo1 channels may represent a novel therapeutic target for maladaptive vascular remodelling and occlusive vascular diseases.

Sphingosine kinase 1 inhibition aggravates vascular smooth muscle cell calcification.

Medial vascular calcification is common in chronic kidney disease patients and linked to hyperphosphatemia. Upon phosphate exposure, intricate signaling events orchestrate pro-calcific effects in the vasculature mediated by vascular smooth muscle cells (VSMCs). Sphingosine kinase 1 (SPHK1) produces sphingosine-1-phosphate (S1P) and is associated with complex effects in the vascular system. The present study investigated a possible involvement of SPHK1 in VSMC calcification. Experiments were performed in primary human aortic VSMCs under pro-calcific conditions, with pharmacological inhibition or knockdown of SPHK1 or SPNS2 (a lysolipid transporter involved in cellular S1P export), as well as in Sphk1-deficient and wild-type mice treated with cholecalciferol. In VSMCs, SPHK1 expression was up-regulated by pro-calcific conditions. Calcification medium up-regulated osteogenic marker mRNA expression and activity as well as calcification of VSMCs, effects significantly augmented by co-treatment with the SPHK1 inhibitor SK1-IN-1. SK1-IN-1 alone was sufficient to up-regulate osteogenic signaling in VSMCs during control conditions. Similarly, the SPHK1 inhibitor PF-543 and SPHK1 knockdown up-regulated osteogenic signaling in VSMCs and aggravated VSMC calcification. In contrast, co-treatment with the SPNS2 inhibitor SLF1081851 suppressed osteogenic signaling and calcification of VSMCs, effects abolished by silencing of SPHK1. In addition, Sphk1 deficiency aggravated vascular calcification and aortic osteogenic marker expression in mice after cholecalciferol overload. In conclusion, SPHK1 inhibition, knockdown, or deficiency aggravates vascular pro-calcific signaling and calcification. The reduced calcification after inhibition of S1P export suggests a possible involvement of intracellular S1P, but further studies are required to elucidate the complex roles of SPHKs and S1P signaling in calcifying VSMCs.

Blood pressure regulation through circadian variation: PRDM16 as a target in vascular smooth muscle cells.

The precise mechanisms of blood pressure (BP) regulation are not fully elucidated, and understanding BP regulation is crucial for managing hypertension and improving outcomes for cardiovascular disease. In this issue of the JCI, Wang et al. identified the transcription factor PR domain-containing protein 16 (PRDM16) as a regulator of both vascular smooth muscle cell contraction and the circadian response to BP control. PRDM16 directly transcriptionally controlled the expression of the adrenergic receptor α 1d and several clock genes crucial for BP circadian regulation. These findings identify a mechanism of how molecular pathways govern circadian BP variation, highlighting PRDM16 as a potential target for hypertension.

The LINC complex in blood vessels: from physiology to pathological implications in arterioles.

The LINC (linker of nucleoskeleton and cytoskeleton) complex is a critical component of the cellular architecture that bridges the nucleoskeleton and cytoskeleton and mediates mechanotransduction to and from the nucleus. Though it plays important roles in all blood vessels, it is in arterioles that this complex plays a pivotal role in maintaining endothelial cell integrity, regulating vascular tone, forming new microvessels and modulating responses to mechanical and biochemical stimuli. It is also important in vascular smooth muscle cells and fibroblasts, where it possibly plays a role in the contractile to secretory phenotypic transformation during atherosclerosis and vascular ageing, and in fibroblasts' migration and inflammatory responses in the adventitia. Physiologically, the LINC complex contributes to the stability of arteriolar structure, adaptations to changes in blood flow and injury repair mechanisms. Pathologically, dysregulation or mutations in LINC complex components can lead to compromised endothelial function, vascular remodelling and exacerbation of cardiovascular diseases such as atherosclerosis (arteriolosclerosis). This review summarizes our current understanding of the roles of the LINC complex in cells from arterioles, highlighting its most important physiological functions, exploring its implications for vascular pathology and emphasizing some of its functional characteristics in endothelial cells. By elucidating the LINC complex's role in health and disease, we aim to provide insights that could improve future therapeutic strategies targeting LINC complex-related vascular disorders.

Vascular Contractility Relies on Integrity of Progranulin Pathway: Insights Into Mitochondrial Function.

The complex interplay between vascular contractility and mitochondrial function is central to cardiovascular disease. The progranulin gene (GRN) encodes glycoprotein PGRN (progranulin), a ubiquitous molecule with known anti-inflammatory property. However, the role of PGRN in cardiovascular disease remains undefined. In this study, we sought to dissect the significance of PGRN in the regulation vascular contractility and investigate the interface between PGRN and mitochondrial quality. We used aortae from male and female C57BL6/J wild-type (PGRN+/+) and B6(Cg)-Grntm1.1Aidi/J (PGRN-/-) mice. Our results showed suppression of contractile activity in PGRN-/-, followed by reduced α-smooth muscle actin expression. Mechanistically, PGRN deficiency suppressed mitochondrial respiration, induced mitochondrial fission, and disturbed autophagy process and redox signaling, while restoration of PGRN levels in aortae from PGRN-/- mice via lentivirus delivery ameliorated contractility and boosted mitochondria activity. In addition, invivo treatment with mitochondrial fission inhibitor restored mitochondrial quality and vascular contractility, while vascular smooth muscle cells overexpressing PGRN displayed higher lysosome biogenesis, accelerated mitophagy flux, and mitochondrial respiration accompanied by vascular hypercontractility. Finally, angiotensin II failed to induce vascular contractility in PGRN-/-, suggesting a key role of PGRN to maintain the vascular tone. Our findings suggest that PGRN preserves the vascular contractility via regulating mitophagy flux, mitochondrial activity and dynamics, and redox signaling. Therefore, loss of PGRN function appears as a pivotal risk factor in cardiovascular disease.

Long Non-Coding RNA Function in Smooth Muscle Cell Plasticity and Atherosclerosis.

In the healthy mature artery, vascular cells, including endothelial cells, smooth muscle cells (SMCs), and fibroblasts are organized in different layers, performing specific functions. SMCs located in the media are in a differentiated state and exhibit a contractile phenotype. However, in response to vascular injury within the intima, stimuli from activated endothelial cells and recruited inflammatory cells reach SMCs and induce a series of remodeling events in them, known as phenotypic switching. Indeed, SMCs retain a certain degree of plasticity and are able to transdifferentiate into other cell types that are crucial for both the formation and development of atherosclerotic lesions. Because of their highly cell-specific expression profiles and their widely recognized contribution to physiological and disease-related biological processes, long non-coding RNAs have received increasing attention in atherosclerosis research. Dynamic fluctuations in their expression have been implicated in the regulation of SMC identity. Sophisticated technologies are now available to allow researchers to access single-cell transcriptomes and study long non-coding RNA function with unprecedented precision. Here, we discuss the state of the art of long non-coding RNAs regulation of SMC phenotypic switching, describing the methodologies used to approach this issue and evaluating the therapeutic perspectives of exploiting long non-coding RNAs as targets in atherosclerosis.

P75NTR antagonist THX-B increases mature nerve growth factor secretion by bladder cells through decreased activity of matrix metalloproteinase-9.

In urine samples from an aging female cohort with overactive bladder syndrome (OAB), the proteolytic activity of matrix metalloproteinase-9 (MMP-9), an enzyme which degrades mature NGF, was elevated and associated with low levels of nerve growth factor (NGF). Given that a substantial portion of urine constituents originate from bladder cellular processes, we examined the synthesis of NGF and MMP-9 in rat urothelial (UROs) and smooth muscle (SMCs) cells in culture. NGF and proNGF were found expressed and released by both cell types while UROs were the major source of secreted MMP-9. THX-B, a highly specific p75NTR antagonist, decreased the expression of MMP-9 resulting in increased mature NGF levels in culture medium of UROs while displaying minor effects on SMCs. Likewise, CRISPR-cas9 genomic deletion of MMP-9 potently increased mature NGF levels in both cell types. On the other hand, THX-B decreased the synthesis and release of α2 Macroglobulin (α2M), a protein that stabilizes proNGF in UROs but increased it in SMCs. THX-B also increased the activity of enzymes furin and matrix metalloproteinase-7 (MMP-7), that convert proNGF to mature NGF in UROs, yielding a net increase in mature NGF and a decrease of proNGF. We conclude that p75NTR is involved in the control of proNGF and mature NGF secretion from bladder cells through modulation of proteolytic activities. Since neurotrophins and binding to their receptors are relevant to pathologies, inhibition of p75NTR by THX-B may be exploited in a therapeutic strategy.