Role of Integrins in Modulating Smooth Muscle Cell Plasticity and Vascular Remodeling: From Expression to Therapeutic Implications

Integrative network analysis of transcriptomics data reveals potential prognostic biomarkers for colorectal cancer

INTRODUCTION

Cross-talk among biological pathways is essential for normal biological function and plays a significant role in cancer progression. Through integrated network analysis, this study explores the significance of pathway cross-talk in colorectal cancer (CRC) development at both the pathway and gene levels.

METHODS

In this study, we integrated the gene expression data with domain knowledge to construct state-dependent pathway cross-talk networks. The significance of the genes involved in pathway cross-talk was assessed by analyzing their association with cancer hallmarks, disease-gene relation, genetic alterations, and survival analysis. We also analyzed the gene regulatory network to identify the dysregulated genes and their role in CRC progression.

RESULTS

Cross-talk was observed between immune-related pathways and pathways associated with cell communication and signaling. The PTPRC gene was identified as a mediator, facilitating interactions within the immune system and other signaling pathways. The rewired interactions of ITGA7 were identified as influential in the epithelial-mesenchymal transition in CRC. This study also highlighted the crucial link between cell communication and vascular smooth muscle contraction pathway in CRC progression. The survival analysis of identified gene clusters showed their significant prognostic value in distinguishing high-risk from low-risk CRC groups, and L1000CDS2 revealed seven potential drug molecules in CRC. Nine dysregulated genes (CTNNB1, EP300, JUN, MYC, NFKB1, RELA, SP1, STAT1, and TP53) emerge as transcription factors acting as common regulators across various pathways.

CONCLUSIONS

This study highlights the crucial role of pathway cross-talk in CRC progression and identified the potential prognostic biomarkers and potential drug molecules.

Unveiling cellular and molecular aspects of ascending thoracic aortic aneurysms and dissections

Ascending thoracic aortic aneurysm (ATAA) remains a significant medical concern, with its asymptomatic nature posing diagnostic and monitoring challenges, thereby increasing the risk of aortic wall dissection and rupture. Current management of aortic repair relies on an aortic diameter threshold. However, this approach underestimates the complexity of aortic wall disease due to important knowledge gaps in understanding its underlying pathologic mechanisms.Since traditional risk factors cannot explain the initiation and progression of ATAA leading to dissection, local vascular factors such as extracellular matrix (ECM) and vascular smooth muscle cells (VSMCs) might harbor targets for early diagnosis and intervention. Derived from diverse embryonic lineages, VSMCs exhibit varied responses to genetic abnormalities that regulate their contractility. The transition of VSMCs into different phenotypes is an adaptive response to stress stimuli such as hemodynamic changes resulting from cardiovascular disease, aging, lifestyle, and genetic predisposition. Upon longer exposure to stress stimuli, VSMC phenotypic switching can instigate pathologic remodeling that contributes to the pathogenesis of ATAA.This review aims to illuminate the current understanding of cellular and molecular characteristics associated with ATAA and dissection, emphasizing the need for a more nuanced comprehension of the impaired ECM-VSMC network.

Exploring Integrin α5β1 as a Potential Therapeutic Target for Pulmonary Arterial Hypertension: Insights from Comprehensive Multicenter Preclinical Studies

Pulmonary arterial hypertension (PAH) is characterized by obliterative vascular remodeling of the small pulmonary arteries (PA) and progressive increase in pulmonary vascular resistance (PVR) leading to right ventricular (RV) failure. Although several drugs are approved for the treatment of PAH, mortality remains high. Accumulating evidence supports a pathological function of integrins in vessel remodeling, which are gaining renewed interest as drug targets. However, their role in PAH remains largely unexplored. We found that the arginine-glycine-aspartate (RGD)-binding integrin α5β1 is upregulated in PA endothelial cells (PAEC) and PA smooth muscle cells (PASMC) from PAH patients and remodeled PAs from animal models. Blockade of the integrin α5β1 or depletion of the α5 subunit resulted in mitotic defects and inhibition of the pro-proliferative and apoptosis-resistant phenotype of PAH cells. Using a novel small molecule integrin inhibitor and neutralizing antibodies, we demonstrated that α5β1 integrin blockade attenuates pulmonary vascular remodeling and improves hemodynamics and RV function in multiple preclinical models. Our results provide converging evidence to consider α5β1 integrin inhibition as a promising therapy for pulmonary hypertension.

One sentence summary

The α5β1 integrin plays a crucial role in pulmonary vascular remodeling.

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.

Integrin α9β1 deficiency does not impact the development of atherosclerosis in mice

Sushi, von Willebrand factor type A, EGF and pentraxin domain containing 1 (SVEP1) is an extracellular matrix protein that causally promotes cardiovascular disease in humans and mice. However, the receptor mediating the effect of SVEP1 on the development of disease remains unclear. We previously demonstrated that depleting either vascular smooth muscle cell (VSMC)- or myeloid cell-derived integrin α9β1, the first receptor that was identified to interact with SVEP1, did not phenocopy the disease-abrogating effect of depleting SVEP1. Due to its wide expression in tissues and cell types, here we extend this line of investigation to definitively determine if integrin α9β1 impacts the development of atherosclerosis. In a mouse model of atherosclerosis, we found that depleting integrin α9β1 in all cells did not alter plaque size or characteristics of plaque complexity when compared to wild type mice. Further, the significant SVEP1-mediated effects on increase in macrophage content and VSMC proliferation within the atherosclerotic plaque were not altered in animals lacking integrin α9β1. Together, these findings strongly suggest that integrin α9β1 is not responsible for mediating the SVEP1-induced promotion of atherosclerosis and support further studies aimed at characterizing other receptors whose interaction with SVEP1 may represent a therapeutically targetable interaction.

Extracellular SOD modulates canonical TNFα signaling and α5β1 integrin transactivation in vascular smooth muscle cells

TNFα activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs). The extracellular superoxide anion (O2•-) produced is essential for the pro-inflammatory effects of the cytokine but the specific contributions of O2•- to signal transduction remain obscure. Extracellular superoxide dismutase (ecSOD, SOD3 gene) is a secreted protein that binds to cell surface heparin sulfate proteoglycans or to Fibulin-5 (Fib-5, FBLN5 gene), an extracellular matrix protein that also associates with elastin and integrins. ecSOD converts O2•- to hydrogen peroxide (H2O2) which prevents NO• inactivation, limits generation of hydroxyl radical (OH•), and creates high local concentrations of H2O2. We hypothesized that ecSOD modifies TNFα signaling in VSMCs. Knockdown of ecSOD (siSOD3) suppressed downstream TNFα signals including MAPK (JNK and ERK phosphorylation) and NF-κB activation (luciferase reporter and IκB phosphorylation), interleukin-6 (IL-6) secretion, iNOS and VCAM expression, and proliferation (Sulforhodamine B assay, PCNA western blot). These effects were associated with significant reductions in the expression of both Type1 and 2 TNFα receptors. Reduced Fib-5 expression (siFBLN5) similarly impaired NF-κB activation by TNFα, but potentiated FAK phosphorylation at Y925. siSOD3 also increased both resting and TNFα-induced phosphorylation of FAK and of glycogen synthase kinase-3β (GSK3β), a downstream target of integrin linked kinase (ILK). These effects were dependent upon α5β1 integrins and siSOD3 increased resting sulfenylation (oxidation) of both integrin subunits, while preventing TNFα-induced increases in sulfenylation. To determine how ecSOD modified TNFα-induced inflammation in intact blood vessels, mesenteric arteries from VSMC-specific ecSOD knockout (KO) mice were exposed to TNFα (10 ng/ml) in culture for 48 h. Relaxation to acetylcholine and sodium nitroprusside was impaired in WT but not ecSOD KO vessels. Thus, ecSOD association with Fib-5 supports pro-inflammatory TNFα signaling while tonically inhibiting α5β1 integrin activation.

Extracellular Matrix Remodeling in Vascular Disease: Defining Its Regulators and Pathological Influence

Because of structural and cellular differences (ie, degrees of matrix abundance and cross-linking, mural cell density, and adventitia), large and medium-sized vessels, in comparison to capillaries, react in a unique manner to stimuli that induce vascular disease. A stereotypical vascular injury response is ECM (extracellular matrix) remodeling that occurs particularly in larger vessels in response to injurious stimuli, such as elevated angiotensin II, hyperlipidemia, hyperglycemia, genetic deficiencies, inflammatory cell infiltration, or exposure to proinflammatory mediators. Even with substantial and prolonged vascular damage, large- and medium-sized arteries, persist, but become modified by (1) changes in vascular wall cellularity; (2) modifications in the differentiation status of endothelial cells, vascular smooth muscle cells, or adventitial stem cells (each can become activated); (3) infiltration of the vascular wall by various leukocyte types; (4) increased exposure to critical growth factors and proinflammatory mediators; and (5) marked changes in the vascular ECM, that remodels from a homeostatic, prodifferentiation ECM environment to matrices that instead promote tissue reparative responses. This latter ECM presents previously hidden matricryptic sites that bind integrins to signal vascular cells and infiltrating leukocytes (in coordination with other mediators) to proliferate, invade, secrete ECM-degrading proteinases, and deposit injury-induced matrices (predisposing to vessel wall fibrosis). In contrast, in response to similar stimuli, capillaries can undergo regression responses (rarefaction). In summary, we have described the molecular events controlling ECM remodeling in major vascular diseases as well as the differential responses of arteries versus capillaries to key mediators inducing vascular injury.

Lineage-Specific Induced Pluripotent Stem Cell-Derived Smooth Muscle Cell Modeling Predicts Integrin Alpha-V Antagonism Reduces Aortic Root Aneurysm Formation in Marfan Syndrome Mice

BACKGROUND

The role of increased smooth muscle cell (SMC) integrin αv signaling in Marfan syndrome (MFS) aortic aneurysm remains unclear. Herein, we examine the mechanism and potential efficacy of integrin αv blockade as a therapeutic strategy to reduce aneurysm progression in MFS.

METHODS

Induced pluripotent stem cells (iPSCs) were differentiated into aortic SMCs of the second heart field (SHF) and neural crest (NC) lineages, enabling in vitro modeling of MFS thoracic aortic aneurysms. The pathological role of integrin αv during aneurysm formation was confirmed by blockade of integrin αv with GLPG0187 in Fbn1C1039G/+ MFS mice.

RESULTS

iPSC-derived MFS SHF SMCs overexpress integrin αv relative to MFS NC and healthy control SHF cells. Furthermore, integrin αv downstream targets (FAK [focal adhesion kinase]/AktThr308/mTORC1 [mechanistic target of rapamycin complex 1]) were activated, especially in MFS SHF. Treatment of MFS SHF SMCs with GLPG0187 reduced p-FAK/p-AktThr308/mTORC1 activity back to control SHF levels. Functionally, MFS SHF SMCs had increased proliferation and migration compared to MFS NC SMCs and control SMCs, which normalized with GLPG0187 treatment. In the Fbn1C1039G/+ MFS mouse model, integrin αv, p-AktThr308, and downstream targets of mTORC1 proteins were elevated in the aortic root/ascending segment compared to littermate wild-type control. Mice treated with GLPG0187 (age 6-14 weeks) had reduced aneurysm growth, elastin fragmentation, and reduction of the FAK/AktThr308/mTORC1 pathway. GLPG0187 treatment reduced the amount and severity of SMC modulation assessed by single-cell RNA sequencing.

CONCLUSIONS

The integrin αv-FAK-AktThr308 signaling pathway is activated in iPSC SMCs from MFS patients, specifically from the SHF lineage. Mechanistically, this signaling pathway promotes SMC proliferation and migration in vitro. As biological proof of concept, GLPG0187 treatment slowed aneurysm growth and p-AktThr308 signaling in Fbn1C1039G/+ mice. Integrin αv blockade via GLPG0187 may be a promising therapeutic approach to inhibit MFS aneurysmal growth.

Non-Haemodynamic Mechanisms Underlying Hypertension-Associated Damage in Target Kidney Components

Arterial hypertension (AH) is a global challenge that greatly impacts cardiovascular morbidity and mortality worldwide. AH is a major risk factor for the development and progression of kidney disease. Several antihypertensive treatment options are already available to counteract the progression of kidney disease. Despite the implementation of the clinical use of renin-angiotensin aldosterone system (RAAS) inhibitors, gliflozins, endothelin receptor antagonists, and their combination, the kidney damage associated with AH is far from being resolved. Fortunately, recent studies on the molecular mechanisms of AH-induced kidney damage have identified novel potential therapeutic targets. Several pathophysiologic pathways have been shown to play a key role in AH-induced kidney damage, including inappropriate tissue activation of the RAAS and immunity system, leading to oxidative stress and inflammation. Moreover, the intracellular effects of increased uric acid and cell phenotype transition showed their link with changes in kidney structure in the early phase of AH. Emerging therapies targeting novel disease mechanisms could provide powerful approaches for hypertensive nephropathy management in the future. In this review, we would like to focus on the interactions of pathways linking the molecular consequences of AH to kidney damage, suggesting how old and new therapies could aim to protect the kidney.

Detection of Early Endothelial Dysfunction by Optoacoustic Tomography

Variations in vascular wall shear stress are often presumed to result in the formation of atherosclerotic lesions at specific arterial regions, where continuous laminar flow is disturbed. The influences of altered blood flow dynamics and oscillations on the integrity of endothelial cells and the endothelial layer have been extensively studied in vitro and in vivo. Under pathological conditions, the Arg-Gly-Asp (RGD) motif binding integrin α_vβ₃ has been identified as a relevant target, as it induces endothelial cell activation. Animal models for in vivo imaging of endothelial dysfunction (ED) mainly rely on genetically modified knockout models that develop endothelial damage and atherosclerotic plaques upon hypercholesterolemia (ApoE^-/- and LDLR^-/-), thereby depicting late-stage pathophysiology. The visualization of early ED, however, remains a challenge. Therefore, a carotid artery cuff model of low and oscillating shear stress was applied in CD-1 wild-type mice, which should be able to show the effects of altered shear stress on a healthy endothelium, thus revealing alterations in early ED. Multispectral optoacoustic tomography (MSOT) was assessed as a non-invasive and highly sensitive imaging technique for the detection of an intravenously injected RGD-mimetic fluorescent probe in a longitudinal (2-12 weeks) study after surgical cuff intervention of the right common carotid artery (RCCA). Images were analyzed concerning the signal distribution upstream and downstream of the implanted cuff, as well as on the contralateral side as a control. Subsequent histological analysis was applied to delineate the distribution of relevant factors within the carotid vessel walls. Analysis revealed a significantly enhanced fluorescent signal intensity in the RCCA upstream of the cuff compared to the contralateral healthy side and the downstream region at all time points post-surgery. The most obvious differences were recorded at 6 and 8 weeks after implantation. Immunohistochemistry revealed a high degree of α_v-positivity in this region of the RCCA, but not in the left common carotid artery (LCCA) or downstream of the cuff. In addition, macrophages could be detected by CD68 immunohistochemistry in the RCCA, showing ongoing inflammatory processes. In conclusion, MSOT is capable of delineating alterations in endothelial cell integrity in vivo in the applied model of early ED, where an elevated expression of integrin α_vβ₃ was detected within vascular structures.

Homeobox A9 is a novel mediator of vascular smooth muscle cell phenotypic switching and proliferation by regulating methyl-CpG binding protein 2

Aberrant proliferation and phenotypic switching of vascular smooth muscle cells (VSMCs) are considered to be the main pathological processes of atherosclerotic plaque formation. Methyl-CpG binding protein 2 (MECP2) affects cell differentiation via modulating VSMC-specific gene expression and acts as a driver for the development of atherosclerosis (AS). Here, we aimed to elucidate (Rafieian-Kopaei et al., 2014 [1]) the role of homeobox A9 (HOXA9) on aberrant VSMCs upon injury or AS, and (Rana et al., 2021 [2]) whether HOXA9-mediated VSMC injury was associated with MECP2. Adeno-associated virus serotype 8-mediated knockdown of HOXA9 rescued aortic pathological injury of apolipoprotein E-deficient (ApoE^-/-) mice fed a high-fat diet (HFD), characterized by the reduction of lipid accumulation and foam cell formation. Further in vitro evidence suggested that proliferation and migration of primary mouse VSMCs (mVSMCs) stimulated by oxidized low-density lipoprotein (ox-LDL) were inhibited after HOXA9 silencing. In addition, HOXA9 silencing blocked VSMC phenotypic switching from contractile to a pathological synthetic state. HOXA9 overexpression caused opposite alterations in ox-LDL-stimulated mVSMCs. Mechanistically, MECP2 was transcriptionally activated by HOXA9. Forced expression of MECP2 impaired the anti-proliferation, anti-migration, and phenotypic switching abilities of HOXA9 silencing in VSMCs upon ox-LDL stimulation. Collectively, our findings reveal that the role of HOXA9 in pathological vascular remodeling may attribute to transcriptional regulation of MECP2.

Role of Uric Acid in Vascular Remodeling: Cytoskeleton Changes and Migration in VSMCs

The mechanisms by which hyperuricemia induces vascular dysfunction and contributes to cardiovascular disease are still debated. Phenotypic transition is a property of vascular smooth muscle cells (VSMCs) involved in organ damage. The aim of this study was to investigate the effects of uric acid (UA) on changes in the VSMC cytoskeleton, cell migration and the signals involved in these processes. MOVAS, a mouse VSMC line, was incubated with 6, 9 and 12 mg/dL of UA, angiotensin receptor blockers (ARBs), proteasome and MEK-inhibitors. Migration property was assessed in a micro-chemotaxis chamber and by phalloidin staining. Changes in cytoskeleton proteins (Smoothelin B (SMTB), alpha-Smooth Muscle Actin (αSMA), Smooth Muscle 22 Alpha (SM22α)), Atrogin-1 and MAPK activation were determined by Western blot, immunostaining and quantitative reverse transcription PCR. UA exposition modified SMT, αSMA and SM22α levels (p < 0.05) and significantly upregulated Atrogin-1 and MAPK activation. UA-treated VSMCs showed an increased migratory rate as compared to control cells (p < 0.001) and a re-arrangement of F-actin. Probenecid, proteasome inhibition and ARBs prevented the development of dysfunctional VSMC. This study shows, for the first time, that UA-induced cytoskeleton changes determine an increase in VSMC migratory rate, suggesting UA as a key player in vascular remodeling.

Two-Dimensional Peptide Assembly via Arene-Perfluoroarene Interactions for Proliferation and Differentiation of Myoblasts

Supramolecular assembly based on aromatic interactions can provide well-defined nanostructures with an understanding of intermolecular interactions at the molecular level. The peptide assembly via a supramolecular approach can overcome the inherent limitations of bioactive peptides, such as proteolytic degradations and rapid internalizations into the cytosol. Although extensive research has been carried out on supramolecular peptide materials with a two-dimensional (2D) structure, more needs to be reported on biological activity studies using well-defined 2D peptide materials. Physical and chemical properties of the 2D peptide assembly attributed to their large surface area and flexibility can show low cytotoxicity, enhanced molecular loading, and higher bioconjugation efficiency in biological applications. Here, we report supramolecular 2D materials based on the pyrene-grafted amphiphilic peptide, which contains a peptide sequence (Asp-Gly-Glu-Ala; DGEA) that is reported to bind to the integrin α2β1 receptor in 2D cell membranes. The addition of octafluoronaphthalene (OFN) to the pyrene-grafted peptide could induce a well-ordered 2D assembly by face-centered arene-perfluoroarene stacking. The DGEA-peptide 2D assembly with a flat structure, structural stability against enzymatic degradations, and a larger size can enhance the proliferation and differentiation of muscle cells via continuous interactions with cell membrane receptors integrin α2β1 showing a low intracellular uptake (15%) compared to that (62%) of the vesicular peptide assembly. These supramolecular approaches via the arene-perfluoroarene interaction provide a strategy to fabricate well-defined 2D peptide materials with an understanding of assembly at the molecular level for the next-generation peptide materials.

Exploration of N6-Methyladenosine Profiles of mRNAs and the Function of METTL3 in Atherosclerosis

Objectives: N6-methylladenosine (m6A) modification has not been fully studied in atherosclerosis. The objectives of this study were to investigate differentially expressed m6A methylated peaks and mRNAs, along with the regulatory role of methyltransferase 3 (METTL3) in pathological processes of atherosclerosis. Methods: The pathological models of human coronary artery smooth muscle cells (HCASMCs) were induced in vitro. The differentially expressed mRNAs and m6A peaks were identified by RNA-Seq and meRIP-Seq. The potential mechanisms were analyzed via bioinformatic assays. Methylases expression was tested by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB) in HCASMCs, and by immunohistochemical assays in 40 human coronary arteries. The knockdown of METTL3 expression in cells was performed by siRNA transfection, and cell proliferation and migration were detected after transfection. Results: We identified 5121 m6A peaks and 883 mRNAs that were expressed differentially in the pathological processes of HCASMCs. Bioinformatic analyses showed that the different m6A peaks were associated with cell growth and cell adhesion, and the 883 genes showed that the extracellular matrix and PI3K/AKT pathway regulate the processes of HCASMCs. Additionally, 10 hub genes and 351 mRNAs with differential methylation and expression levels were found. METTL3 was upregulated in the arteries with atherosclerotic lesions and in the proliferation and migration model of HCASMCs, and pathological processes of HCASMCs could be inhibited by the knockdown of METTL3. The mechanisms behind regulation of migration and proliferation reduced by siMETTL3 are concerned with protein synthesis and energy metabolism. Conclusions: These results revealed a new m6A epigenetic method to regulate the progress of atherosclerosis, which suggest approaches for potential therapeutic interventions that target METTL3 for the prevention and treatment of coronary artery diseases.

Deletion of Mechanosensory β1-integrin From Bladder Smooth Muscle Results in Voiding Dysfunction and Tissue Remodeling

The bladder undergoes large shape changes as it fills and empties and experiences complex mechanical forces. These forces become abnormal in diseases of the lower urinary tract such as overactive bladder, neurogenic bladder, and urinary retention. As the primary mechanosensors linking the actin cytoskeleton to the extracellular matrix (ECM), integrins are likely to play vital roles in maintaining bladder smooth muscle (BSM) homeostasis. In a tamoxifen-inducible smooth muscle conditional knockout of β1-integrin, there was concomitant loss of α1- and α3-integrins from BSM and upregulation of αV- and β3-integrins. Masson's staining showed a reduction in smooth muscle with an increase in collagenous ECM. Functionally, mice exhibited a changing pattern of urination by voiding spot assay up to 8 wk after tamoxifen. By 8 wk, there was increased frequency with reductions in voided volume, consistent with overactivity. Cystometrograms confirmed that there was a significant reduction in intercontractile interval with reduced maximal bladder pressure. Muscle strip myography revealed a loss of contraction force in response to electrical field stimulation, that was entirely due to the loss of muscarinic contractility. Quantitative western blotting showed a loss of M3 receptor and no change in P2X1. qPCR on ECM and interstitial genes revealed loss of Ntpd2, a marker of an interstitial cell subpopulation; and an upregulation of S100A4, which is often associated with fibroblasts. Collectively, the data show that the loss of appropriate mechanosensation through integrins results in cellular and extracellular remodeling, and concomitant bladder dysfunction that resembles lower urinary tract symptoms seen in older people.

Restenosis after Coronary Stent Implantation: Cellular Mechanisms and Potential of Endothelial Progenitor Cells (A Short Guide for the Interventional Cardiologist)

Coronary stents are among the most common therapies worldwide. Despite significant improvements in the biocompatibility of these devices throughout the last decades, they are prone, in as many as 10–20% of cases, to short- or long-term failure. In-stent restenosis is a multifactorial process with a complex and incompletely understood pathophysiology in which inflammatory reactions are of central importance. This review provides a short overview for the clinician on the cellular types responsible for restenosis with a focus on the role of endothelial progenitor cells. The mechanisms of restenosis are described, along with the cell-based attempts made to prevent it. While the focus of this review is principally clinical, experimental evidence provides some insight into the potential implications for prevention and therapy of coronary stent restenosis.

Pathways of integrins in the endo-lysosomal system

In this review, we present recent scientific advances about integrin trafficking in the endo-lysosomal system. In the last few years, plenty of new information has emerged about the endo-lysosomal system, integrins, and the mechanism, how exactly the intracellular trafficking of integrins is regulated. We review the internalization and recycling pathways of integrins, and we provide information about the possible ways of lysosomal degradation through the endosomal and autophagic system. The regulation of integrin internalization and recycling proved to be a complex process worth studying. Trafficking of integrins, together with the regulation of their gene expression, defines cellular adhesion and cellular migration through bidirectional signalization and ligand binding. Thus, any malfunction in this system can potentially (but not necessarily) lead to tumorigenesis or metastasis. Hence, extensive examinations of integrins in the endo-lysosomal system raise the possibility to identify potential new medical targets. Furthermore, this knowledge can also serve as a basis for further determination of integrin signaling- and adhesion-related processes.