Endothelial cells and macrophages as allies in the healthy and diseased brain.

Diseases of the central nervous system (CNS) are often associated with vascular disturbances or inflammation and frequently both. Consequently, endothelial cells and macrophages are key cellular players that mediate pathology in many CNS diseases. Macrophages in the brain consist of the CNS-associated macrophages (CAMs) [also referred to as border-associated macrophages (BAMs)] and microglia, both of which are close neighbours or even form direct contacts with endothelial cells in microvessels. Recent progress has revealed that different macrophage populations in the CNS and a subset of brain endothelial cells are derived from the same erythromyeloid progenitor cells. Macrophages and endothelial cells share several common features in their life cycle-from invasion into the CNS early during embryonic development and proliferation in the CNS, to their demise. In adults, microglia and CAMs have been implicated in regulating the patency and diameter of vessels, blood flow, the tightness of the blood-brain barrier, the removal of vascular calcification, and the life-time of brain endothelial cells. Conversely, CNS endothelial cells may affect the polarization and activation state of myeloid populations. The molecular mechanisms governing the pas de deux of brain macrophages and endothelial cells are beginning to be deciphered and will be reviewed here.

Vascular remodelling in cardiovascular diseases: hypertension, oxidation, and inflammation.

Optimal vascular structure and function are essential for maintaining the physiological functions of the cardiovascular system. Vascular remodelling involves changes in vessel structure, including its size, shape, cellular and molecular composition. These changes result from multiple risk factors and may be compensatory adaptations to sustain blood vessel function. They occur in diverse cardiovascular pathologies, from hypertension to heart failure and atherosclerosis. Dynamic changes in the endothelium, fibroblasts, smooth muscle cells, pericytes or other vascular wall cells underlie remodelling. In addition, immune cells, including macrophages and lymphocytes, may infiltrate vessels and initiate inflammatory signalling. They contribute to a dynamic interplay between cell proliferation, apoptosis, migration, inflammation, and extracellular matrix reorganisation, all critical mechanisms of vascular remodelling. Molecular pathways underlying these processes include growth factors (e.g., vascular endothelial growth factor and platelet-derived growth factor), inflammatory cytokines (e.g., interleukin-1ß and tumour necrosis factor-α), reactive oxygen species, and signalling pathways, such as Rho/ROCK, MAPK, and TGF-ß/Smad, related to nitric oxide and superoxide biology. MicroRNAs and long noncoding RNAs are crucial epigenetic regulators of gene expression in vascular remodelling. We evaluate these pathways for potential therapeutic targeting from a clinical translational perspective. In summary, vascular remodelling, a coordinated modification of vascular structure and function, is crucial in cardiovascular disease pathology.

Matrine alleviates hypoxia-induced inflammation and pulmonary vascular remodelling via RPS5/NF-κB signalling pathway.

Hypoxia-induced vasoconstriction and vascular remodelling are the main pathological features of hypoxic pulmonary arterial hypertension (HPAH), and inflammation is participated in the occurrence of pulmonary vascular remodelling (PVR). Matrine is an alkaloid with the effects of anti-inflammation, antifibrosis and antitumour. But, few studies have explored the role of matrine in regulating PVR, and the related mechanisms are still unknown. In this study, we found that hypoxia-induced pulmonary artery smooth muscle cells (PASMCs) proliferation and inhibited its apoptosis, reduced the expression of ribosomal protein s5 and activated the nuclear factor kappa-B (NF-κB) signalling. Matrine, sildenafil and NF-κB inhibitor Bay 11-7082 could reverse these changes and impel the cell cycle in phase S retardation, and reduced the expression of p50, p65, proliferating cell nuclear antigen (PCNA), Bcl-2. In addition, matrine could lower right ventricular systolic pressure and mean pulmonary artery pressure of rats, α-smooth muscle actin and PCNA expression in pulmonary artery media, the levels of tumor necrosis factor-α and interleuki-1ß, thus improved hypoxia-induced PVR. This study indicated that matrine could alleviate inflammation and improve PVR through reversing the imbalance of proliferation and apoptosis of PASMCs, thus it had a therapeutic effect on HPAH.

Sirtuin 2 deficiency aggravates ageing-induced vascular remodelling in humans and mice.

AIMS: The mechanisms underlying ageing-induced vascular remodelling remain unclear. This study investigates the role and underlying mechanisms of the cytoplasmic deacetylase sirtuin 2 (SIRT2) in ageing-induced vascular remodelling. METHODS AND RESULTS: Transcriptome and quantitative real-time PCR data were used to analyse sirtuin expression. Young and old wild-type and Sirt2 knockout mice were used to explore vascular function and pathological remodelling. RNA-seq, histochemical staining, and biochemical assays were used to evaluate the effects of Sirt2 knockout on the vascular transcriptome and pathological remodelling and explore the underlying biochemical mechanisms. Among the sirtuins, SIRT2 had the highest levels in human and mouse aortas. Sirtuin 2 activity was reduced in aged aortas, and loss of SIRT2 accelerated vascular ageing. In old mice, SIRT2 deficiency aggravated ageing-induced arterial stiffness and constriction-relaxation dysfunction, accompanied by aortic remodelling (thickened vascular medial layers, breakage of elastin fibres, collagen deposition, and inflammation). Transcriptome and biochemical analyses revealed that the ageing-controlling protein p66Shc and metabolism of mitochondrial reactive oxygen species (mROS) contributed to SIRT2 function in vascular ageing. Sirtuin 2 repressed p66Shc activation and mROS production by deacetylating p66Shc at lysine 81. Elimination of reactive oxygen species by MnTBAP repressed the SIRT2 deficiency-mediated aggravation of vascular remodelling and dysfunction in angiotensin II-challenged and aged mice. The SIRT2 coexpression module in aortas was reduced with ageing across species and was a significant predictor of age-related aortic diseases in humans. CONCLUSION: The deacetylase SIRT2 is a response to ageing that delays vascular ageing, and the cytoplasm-mitochondria axis (SIRT2-p66Shc-mROS) is important for vascular ageing. Therefore, SIRT2 may serve as a potential therapeutic target for vascular rejuvenation.

Vascular/epithelial changes as late sequelae after recovery from SARS-COV-2 infection: an in-vivo comparative study.

AIMS: While there is partial evidence of lung lesions in patients suffering from long COVID there are substantial concerns about lung remodelling sequelae after COVID-19 pneumonia. The aim of the present retrospective comparative study was to ascertain morphological features in lung samples from patients undergoing tumour resection several months after SARS-CoV-2 infection. METHODS AND RESULTS: The severity of several lesions with a major focus on the vascular bed was analysed in 2 tumour-distant lung fragments of 41 cases: 21 SARS-CoV-2 (+) lung tumour (LT) patients and 20 SARS-CoV-2 (-) LT patients. A systematic evaluation of several lesions was carried out by combining their scores into a grade of I-III. Tissue SARS-CoV-2 genomic/subgenomic transcripts were also investigated. Morphological findings were compared with clinical, laboratory and radiological data. SARS-CoV-2 (+) LT patients with previous pneumonia showed more severe parenchymal and vascular lesions than those found in SARS-CoV-2 (+) LT patients without pneumonia and SARS-CoV-2 (-) LT patients, mainly when combined scores were used. SARS-CoV-2 viral transcripts were not detected in any sample. SARS-CoV-2 (+) LT patients with pneumonia showed a significantly higher radiological global injury score. No other associations were found between morphological lesions and clinical data. CONCLUSIONS: To our knowledge, this is the first study that, after a granular evaluation of tissue parameters, detected several changes in lungs from patients undergoing tumour resection after SARS-CoV-2 infection. These lesions, in particular vascular remodelling, could have an important impact overall on the future management of these frail patients.

High apoptotic endothelial microparticle levels measured in asthma with elevated IgE and eosinophils.

While asthma is considered an inflammatory-mediated airway epithelial and smooth muscle disorder, there is increasing evidence of airway capillary endothelial dysfunction associated with vascular remodelling and angiogenesis in some individuals with this condition. The inflammation is typically characterized as type-2 high (eosinophilic) vs type 2-low (neutrophilic and pauci-granulocytic); we hypothesized that the type-2 high group would be more likely to evidence endothelial dysfunction. As a biomarker of these processes, we hypothesized that nonsmokers with allergic asthma may have elevated plasma levels of endothelial microparticles (EMPs), membrane vesicles that are shed when endothelial cells undergo activation or apoptosis. Total and apoptotic circulating EMPs were measured by fluorescence-activated cell analysis in patients with allergic asthma (n = 29) and control subjects (n = 26), all nonsmokers. When the entire group of patients with asthma were compared to the control subjects, there were no differences in total circulating EMPs nor apoptotic EMPs. However, patients with asthma with elevated levels of IgE and eosinophils had higher levels of apoptotic EMPs, compared to patients with asthma with mildly increased IgE and eosinophil levels. This observation is relevant to precision therapies for asthma and highlights the importance of sub-phenotyping in the condition.

Circ-Ntrk2 acts as a miR-296-5p sponge to activate the TGF-ß1/p38 MAPK pathway and promote pulmonary hypertension and vascular remodelling.

BACKGROUND: Circular RNAs (circRNAs), a novel class of non-coding RNAs, play an important regulatory role in pulmonary arterial hypertension (PAH); however, the specific mechanism is rarely studied. In this study, we aimed to discover functional circRNAs and investigate their effects and mechanisms in hypoxia-induced pulmonary vascular remodelling, a core pathological change in PAH. METHODS: RNA sequencing was used to illustrate the expression profile of circRNAs in hypoxic PAH. Bioinformatics, Sanger sequencing, and quantitative real-time PCR were used to identify the ring-forming characteristics of RNA and analyse its expression. Then, we established a hypoxia-induced PAH mouse model to evaluate circRNA function in PAH by echocardiography and hemodynamic measurements. Moreover, microRNA target gene database screening, fluorescence in situ hybridisation, luciferase reporter gene detection, and western blotting were used to explore the mechanism of circRNAs. RESULTS: RNA sequencing identified 432 differentially expressed circRNAs in mouse hypoxic lung tissues. Our results indicated that circ-Ntrk2 is a stable cytoplasmic circRNA derived from Ntrk2 mRNA and frequently upregulated in hypoxic lung tissue. We further found that circ-Ntrk2 sponges miR-296-5p and miR-296-5p can bind to the 3'-untranslated region of transforming growth factor-ß1 (TGF-ß1) mRNA, thereby attenuating TGF-ß1 translation. Through gene knockout or exogenous expression, we demonstrated that circ-Ntrk2 could promote PAH and vascular remodelling. Moreover, we verified that miR-296-5p overexpression alleviated pulmonary vascular remodelling and improved PAH through the TGF-ß1/p38 MAPK pathway. CONCLUSIONS: We identified a new circRNA (circ-Ntrk2) and explored its function and mechanism in PAH, thereby establishing potential targets for the diagnosis and treatment of PAH. Furthermore, our study contributes to the understanding of circRNA in relation to PAH.

Pulmonary vascular reactivity to supplemental oxygen in Sherpa and lowlanders during gradual ascent to high altitude.

NEW FINDINGS: What is the central question of this study? How does hypoxic pulmonary vasoconstriction and the response to supplemental oxygen change over time at high altitude? What is the main finding and its importance? Lowlanders and partially de-acclimatized Sherpa both demonstrated pulmonary vascular responsiveness to supplemental oxygen that was maintained for 12 days' exposure to progressively increasing altitude. An additional 2 weeks' acclimatization at 5050 m altitude rendered the pulmonary vasculature minimally responsive to oxygen similar to the fully acclimatized non-ascent Sherpa. Additional hypoxic exposure at that time point did not augment hypoxic pulmonary vasoconstriction. ABSTRACT: Prolonged alveolar hypoxia leads to pulmonary vascular remodelling. We examined the time course at altitude, over which hypoxic pulmonary vasoconstriction goes from being acutely reversible to potentially irreversible. Study subjects were lowlanders (n = 20) and two Sherpa groups. All Sherpa were born and raised at altitude. One group (ascent Sherpa, n = 11) left altitude and after de-acclimatization in Kathmandu for ∼7 days re-ascended with the lowlanders over 8-10 days to 5050 m. The second Sherpa group (non-ascent Sherpa, n = 12) remained continuously at altitude. Pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) were measured while breathing ambient air and following supplemental oxygen. During ascent PASP and PVR increased in lowlanders and ascent Sherpa; however, with supplemental oxygen, lowlanders had significantly greater decrease in PASP (P = 0.02) and PVR (P = 0.02). After ∼14 days at 5050 m, PASP decreased with supplemental oxygen (mean decrease: 3.9 mmHg, 95% CI 2.1-5.7 mmHg, P < 0.001); however, PVR was unchanged (P = 0.49). In conclusion, PASP and PVR increased with gradual ascent to altitude and decreased via oxygen supplementation in both lowlanders and ascent Sherpa. Following ∼14 days at 5050 m altitude, there was no change in PVR to hypoxia or O2  supplementation in lowlanders or either Sherpa group. These data show that both duration of exposure and residential altitude influence the pulmonary vascular responses to hypoxia.

piRNA-823 is a novel potential therapeutic target in aortic dissection.

Aortic dissection (AD) presents a medical challenge for clinicians. Here, to determine the role of a novel small non-coding piRNA-823 (piR-823) in AD, murine and human aorta from patients with AD were used. A high expression levels of piR-823 were found in patients with AD. Using performed loss- and gain-of-function assays in vitro and in vivo, we explore the regulatory effect of piR-823 on vascular smooth muscle cells (VSMCs) and AD. piR-823 obviously facilitates the proliferation, migration, and phenotypic transformation of VSMCs with or without nicotine treatment. piR-823 directly binds and suppresses histone deacetylase 1 (HDAC1) expression, and regulates the acetylation of histone 3 (H3) via H3K9ac and H3K27ac, eventually, VSMC functions and AD. To consolidate our findings, AD murine model was performed, and we observed that piR-823 antagomir strongly inhibited the pathogenesis of AD through regulating vascular remodeling. Thus, our study finds a potential target for the prevention and treatment strategy for nicotine-induced AD.

Building a Scaffold for Arteriovenous Fistula Maturation: Unravelling the Role of the Extracellular Matrix.

Vascular access is the lifeline for patients receiving haemodialysis as kidney replacement therapy. As a surgically created arteriovenous fistula (AVF) provides a high-flow conduit suitable for cannulation, it remains the vascular access of choice. In order to use an AVF successfully, the luminal diameter and the vessel wall of the venous outflow tract have to increase. This process is referred to as AVF maturation. AVF non-maturation is an important limitation of AVFs that contributes to their poor primary patency rates. To date, there is no clear overview of the overall role of the extracellular matrix (ECM) in AVF maturation. The ECM is essential for vascular functioning, as it provides structural and mechanical strength and communicates with vascular cells to regulate their differentiation and proliferation. Thus, the ECM is involved in multiple processes that regulate AVF maturation, and it is essential to study its anatomy and vascular response to AVF surgery to define therapeutic targets to improve AVF maturation. In this review, we discuss the composition of both the arterial and venous ECM and its incorporation in the three vessel layers: the tunica intima, media, and adventitia. Furthermore, we examine the effect of chronic kidney failure on the vasculature, the timing of ECM remodelling post-AVF surgery, and current ECM interventions to improve AVF maturation. Lastly, the suitability of ECM interventions as a therapeutic target for AVF maturation will be discussed.

Calpain-1 mediates vascular remodelling and fibrosis via HIF-1α in hypoxia-induced pulmonary hypertension.

Calpain-1, a calcium-activated neutral cysteine proteases, has been reported to be involved in the formation of pulmonary hypertension. HIF-1α, an oxygen-sensitive transcription factor, has been reported to activate genes involved in cell proliferation and extracellular matrix recombination. This study was designed to investigate the effect of calpain-1 in hypoxic pulmonary hypertension (HPH) and to explore whether there is a relationship between calpain-1 and HIF-1α in this disease. In the hypoxia-induced model of HPH, we found that hypoxia resulted in increased right ventricular systolic pressure, right ventricular hypertrophy, pulmonary vascular remodelling and collagen deposition in lung tissues of mice. The levels of calpain-1 and HIF-1α were up-regulated in the lung tissues of hypoxia-treated mice and pulmonary arterial smooth muscle cells (PASMCs). Knock-out of calpain-1 restrained haemodynamic and histological changes induced by chronic hypoxia in mice, and inhibition of calpain-1 also repressed the abnormal proliferation and migration of PASMCs. Besides, knock-out or inhibition of calpain-1 suppressed hypoxia-induced expression of HIF-1α, VEGF, PCNA, TGF-ß1, MMP2 and collagen I in vivo and in vitro. While inhibition of HIF-1α abolished the above effects of calpain-1. Furthermore, we found that calpain-1 mediates the expression of HIF-1α through NF-κB (P65) under hypoxia conditions. In conclusion, our results suggest that calpain-1 plays a pivotal role in hypoxia-induced pulmonary vascular remodelling and fibrosis through HIF-1α, providing a better understanding of the pathogenesis of HPH.

Inhibition of the prolyl isomerase Pin1 improves endothelial function and attenuates vascular remodelling in pulmonary hypertension by inhibiting TGF-ß signalling.

Pulmonary arterial hypertension (PAH) is a devastating disease, characterized by obstructive pulmonary vascular remodelling ultimately leading to right ventricular (RV) failure and death. Disturbed transforming growth factor-ß (TGF-ß)/bone morphogenetic protein (BMP) signalling, endothelial cell dysfunction, increased proliferation of smooth muscle cells and fibroblasts, and inflammation contribute to this abnormal remodelling. Peptidyl-prolyl isomerase Pin1 has been identified as a critical driver of proliferation and inflammation in vascular cells, but its role in the disturbed TGF-ß/BMP signalling, endothelial cell dysfunction, and vascular remodelling in PAH is unknown. Here, we report that Pin1 expression is increased in cultured pulmonary microvascular endothelial cells (MVECs) and lung tissue of PAH patients. Pin1 inhibitor, juglone significantly decreased TGF-ß signalling, increased BMP signalling, normalized their hyper-proliferative, and inflammatory phenotype. Juglone treatment reversed vascular remodelling through reducing TGF-ß signalling in monocrotaline + shunt-PAH rat model. Juglone treatment decreased Fulton index, but did not affect or harm cardiac function and remodelling in rats with RV pressure load induced by pulmonary artery banding. Our study demonstrates that inhibition of Pin1 reversed the PAH phenotype in PAH MVECs in vitro and in PAH rats in vivo, potentially through modulation of TGF-ß/BMP signalling pathways. Selective inhibition of Pin1 could be a novel therapeutic option for the treatment of PAH.

Pioglitazone attenuates ischaemic stroke aggravation by blocking PPARγ reduction and inhibiting chronic inflammation in diabetic mice.

Diabetes can cause vascular remodelling and is associated with worse outcome after ischaemic stroke. Pioglitazone is a commonly used anti-diabetic agent. However, it is not known whether pioglitazone use before ischaemia could reduce brain ischaemic injury. Pioglitazone was administered to 5-week-old db+ or db/db mice. Cerebral vascular remodelling was examined at the age of 9 weeks. Expression of peroxisome proliferator-activated receptor-γ (PPARγ), p-PPARγ (S112 and S273), nucleotide-binding domain (NOD)-like receptor protein 3 (Nlrp3), interleukin-1ß (IL-1ß) and tumour necrosis factor-α (TNF-α) was evaluated in the somatosensory cortex of mice. Neurological outcome was evaluated 24 h after brain ischaemia. Results showed that early pioglitazone treatment provided a long-lasting effect of euglycaemia but enhanced hyperlipidaemia in the db/db mice. Diabetic mice exhibited increased vascular tortuosity, narrower middle cerebral artery (MCA) width and IgG leakage in the brain. These changes were blocked by early pioglitazone treatment. In diabetic animals, PPARγ expression was reduced, and p-PPARγ at S273 but not S112, Nlrp3, IL-1ß and TNF-α were increased in the somatosensory cortex. PPARγ decrease and Nlrp3 increase were mainly in the neurons of the diabetic brain, which was reversed by early pioglitazone treatment. Pioglitazone attenuated the aggravated neurological outcome after stroke in diabetic mice. But this protective effect was abolished through restoring cerebral inflammation by intracerebroventricular administration of IL-1ß and TNF-α in pioglitazone-treated diabetic mice before MCAO. In summary, early pioglitazone treatment attenuates cerebral vascular remodelling and ischaemic brain injury possibly via blocking chronic neuroinflammation in the db/db mice.

Periostin-related progression of different types of experimental pulmonary hypertension: A role for M2 macrophage and FGF-2 signalling.

BACKGROUND AND OBJECTIVE: Remodelling of pulmonary arteries (PA) contributes to the progression of pulmonary hypertension (PH). Periostin, a matricellular protein, has been reported to be involved in the development of PH. We examined the role of periostin in the pathogenesis of PH using different types of experimental PH. METHODS: PH was induced by vascular endothelial growth factor receptor antagonist (Sugen5416) plus hypoxic exposure (SuHx) and venous injection of monocrotaline-pyrrole (MCT-P) in wild-type (WT) and periostin-/- mice. Pulmonary haemodynamics, PA remodelling, expression of chemokines and fibroblast growth factor (FGF)-2, accumulation of macrophages to small PA and the right ventricle (RV) were examined in PH-induced WT and periostin-/- mice. Additionally, the role of periostin in the migration of macrophages, human PA smooth muscle (HPASMCs) and endothelial cells (HPMVECs) was investigated. RESULTS: In PH induced by SuHx and MCT-P, PH and accumulation of M2 macrophage to small PA were attenuated in periostin-/- mice. PA remodelling post-SuHx treatment was also mild in periostin-/- mice compared to WT mice. Expression of macrophage-associated chemokines and FGF-2 in lung tissue, and accumulation of CD68-positive cells in the RV were less in SuHx periostin-/- than in SuHx WT mice. Periostin secretion in HPASMCs and HPMVECs was enhanced by transforming growth factor-ß. Periostin also augmented macrophage, HPASMCs and HPMVECs migration. Separately, serum periostin levels were significantly elevated in patients with PH compared to healthy controls. CONCLUSION: Periostin is involved in the development of different types of experimental PH, and may also contribute to the pathogenesis of human PH.

Using Confocal Microscopy to Generate an Accurate Vascular Model for Use in Patient Education Animation.

Hypertension is a condition requiring lifelong medication, where patients often feel well with or without treatment. Uncontrolled hypertension, however, can lead to permanent remodelling processes that occur to the vascular structure, which are seldom understood by the public. As a result, a significant burden is placed on healthcare systems globally as a result of the effects of hypertension and lack of adherence to prescribed treatment.Improving patient education through well-designed interactive applications and animation is a known strategy that can improve adherence rates to medication. In the context of hypertension, little attention has been given to helping patients understand the unseen damage that occurs to vessels exposed to high blood pressure. However, generating an accurate representation of a vessel and the changes that occur can be challenging. Using microscopy data is one way for creating an anatomically correct model, but this often needs careful consideration as data cannot be directly imported. Here we describe methods for creating an accurate 3D model of a small artery using confocal microscopy data. This model can then be animated to demonstrate the substructures and pathological changes that occur in hypertensive conditions to better inform patients about the dangers of uncontrolled blood pressure.

circ-BPTF serves as a miR-486-5p sponge to regulate CEMIP and promotes hypoxic pulmonary arterial smooth muscle cell proliferation in COPD.

Hypoxia plays a crucial role in pulmonary vascular remodelling at the early stage of chronic obstructive pulmonary disease (COPD). Circle RNA (circRNA) has been identified to play a critical role in multiple diseases. However, the role of circRNAs in pulmonary vascular remodelling in COPD remains unclear. In this study, we aim to investigate the role of circRNAs in pulmonary arterial smooth muscle cell proliferation and pulmonary vascular remodelling in COPD. COPD patients show lower partial pressure of arterial oxygen and pulmonary arterial remodeling as compared with controls. circRNA microarray and real-time PCR analyses show significantly higher level of circ-BPTF and lower miR-486-5p level in the pulmonary arteries of COPD patients as compared with controls. Hypoxia suppresses miR-486-5p expression but promotes expressions of circ-BPTF and cell migration inducing protein (CEMIP) in human pulmonary arterial smooth muscle cells (PASMCs) in vitro. Loss- and gain-of-function experiments show that circ-BPTF promotes PASMC proliferation in vitro. Moreover, luciferase reporter assay results indicate that circ-BPTF regulates PASMC proliferation by acting as an miR-486-5p sponge. CEMIP is identified as a candidate target gene of miR-486-5p by luciferase reporter assay. Overall, our study shows that circ-BPTF serves as a miR-486-5p sponge to regulate CEMIP and promote hypoxic PASMC proliferation in pulmonary vascular remodelling in COPD.

Deletion of large-conductance calcium-activated potassium channels promotes vascular remodelling through the CTRP7-mediated PI3K/Akt signaling pathway.

The large-conductance calcium-activated potassium (BK) channel is a critical regulator and potential therapeutic target of vascular tone and architecture, and abnormal expression or dysfunction of this channel is linked to many vascular diseases. Vascular remodelling is the early pathological basis of severe vascular diseases. Delaying the progression of vascular remodelling can reduce cardiovascular events, but the pathogenesis remains unclear. To clarify the role of BK channels in vascular remodelling, we use rats with BK channel α subunit knockout (BK α ‒/‒). The results show that BK α ‒/‒ rats have smaller inner and outer diameters, thickened aortic walls, increased fibrosis, and disordered elastic fibers of the aortas compared with WT rats. When the expression and function of BK α are inhibited in human umbilical arterial smooth muscle cells (HUASMCs), the expressions of matrix metalloproteinase 2 (MMP2), MMP9, and interleukin-6 are enhanced, while the expressions of smooth muscle cell contractile phenotype proteins are reduced. RNA sequencing, bioinformatics analysis and qPCR verification show that C1q/tumor necrosis factor-related protein 7 ( CTRP7) is the downstream target gene. Furthermore, except for that of MMPs, a similar pattern of IL-6, smooth muscle cell contractile phenotype proteins expression trend is observed after CTRP7 knockdown. Moreover, knockdown of both BK α and CTRP7 in HUASMCs activates PI3K/Akt signaling. Additionally, CTRP7 is expressed in vascular smooth muscle cells (VSMCs), and BK α deficiency activates the PI3K/Akt pathway by reducing CTRP7 level. Therefore, we first show that BK channel deficiency leads to vascular remodelling. The BK channel and CTRP7 may serve as potential targets for the treatment of cardiovascular diseases.

A proteomic atlas of the neointima identifies novel druggable targets for preventive therapy.

AIMS: In-stent restenosis is a complication after coronary stenting associated with morbidity and mortality. Here, we sought to investigate the molecular processes underlying neointima formation and to identify new treatment and prevention targets. METHODS AND RESULTS: Neointima formation was induced by wire injury in mouse femoral arteries. High-accuracy proteomic measurement of single femoral arteries to a depth of about 5000 proteins revealed massive proteome remodelling, with more than half of all proteins exhibiting expression differences between injured and non-injured vessels. We observed major changes in the composition of the extracellular matrix and cell migration processes. Among the latter, we identified the classical transient receptor potential channel 6 (TRPC6) to drive neointima formation. While Trpc6-/- mice presented reduced neointima formation compared to wild-type mice (1.44 ± 0.39 vs. 2.16 ± 0.48, P = 0.01), activating or repressing TRPC6 in human vascular smooth muscle cells resulted in increased [vehicle 156.9 ± 15.8 vs. 1-oleoyl-2-acetyl-sn-glycerol 179.1 ± 8.07 (103 pixels), P = 0.01] or decreased migratory capacity [vehicle 130.0 ± 26.1 vs. SAR7334 111.4 ± 38.0 (103 pixels), P = 0.04], respectively. In a cohort of individuals with angiographic follow-up (n = 3068, males: 69.9%, age: 59 ± 11 years, follow-up 217.1 ± 156.4 days), homozygous carriers of a common genetic variant associated with elevated TRPC6 expression were at increased risk of restenosis after coronary stenting (adjusted odds ratio 1.49, 95% confidence interval 1.08-2.05; P = 0.01). CONCLUSIONS: Our study provides a proteomic atlas of the healthy and injured arterial wall that can be used to define novel factors for therapeutic targeting. We present TRPC6 as an actionable target to prevent neointima formation secondary to vascular injury and stent implantation.

Immune Cells in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a complex and serious cardiopulmonary disease; it is characterised by increased pulmonary arterial pressure and pulmonary vascular remodelling accompanied by disordered endothelial and smooth muscle cell proliferation within pulmonary arterioles and arteries. Although recent reports have suggested that dysregulated immunity and inflammation are key players in PAH pathogenesis, their roles in PAH progression remain unclear. Intriguingly, altered host immune cell distribution, number, and polarisation within the lung arterial vasculature have been linked to disease development. This review mainly focusses on the roles of different immune cells in PAH and discusses the underlying mechanisms.

NDUFA4L2 in smooth muscle promotes vascular remodeling in hypoxic pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance and obliterative pulmonary vascular remodelling (PVR). The imbalance between the proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) is an important cause of PVR leading to PAH. Mitochondria play a key role in the production of hypoxia-induced pulmonary hypertension (HPH). However, there are still many issues worth studying in depth. In this study, we demonstrated that NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 like 2 (NDUFA4L2) was a proliferation factor and increased in vivo and in vitro through various molecular biology experiments. HIF-1α was an upstream target of NDUFA4L2. The plasma levels of 4-hydroxynonene (4-HNE) were increased both in PAH patients and hypoxic PAH model rats. Knockdown of NDUFA4L2 decreased the levels of malondialdehyde (MDA) and 4-HNE in human PASMCs in hypoxia. Elevated MDA and 4-HNE levels might be associated with excessive ROS generation and increased expression of 5-lipoxygenase (5-LO) in hypoxia, but this effect was blocked by siNDUFA4L2. Further research found that p38-5-LO was a downstream signalling pathway of PASMCs proliferation induced by NDUFA4L2. Up-regulated NDUFA4L2 plays a critical role in the development of HPH, which mediates ROS production and proliferation of PASMCs, suggesting NDUFA4L2 as a potential new therapeutic target for PAH.