Smooth Muscle Cell Hypertrophy Research Articles

The particularities of connective fibers from the wall of varicose veins extirpated by cryostripping.

The varicose vein affects more than 30% of the general population. Significantly increased rates were noticed in women and older population. From the histopathological point of view, venous arterialization, smooth muscle cell hypertrophy, and hyperplasia are the main changes noticed in varicose vein disease. Some of the main therapeutic methods used in the management of varicose disease are injection sclerotherapy, conservative, surgical, saphenous vein inversion and removal, high saphenous ligation, ambulatory phlebectomy, transilluminated powered phlebectomy, endovascular management, cryostripping. The aim of this study was to evaluate the morphology of connective fibers from the wall of the varicose veins extirpated by cryostripping. The study included 109 samples taken by cryostripping method. Hematoxylin-Eosin, Masson's trichrome, Silver and Orcein staining were applied. The assessment of fibers was made according to score values between 0 and 3. It was found no major structural differences in terms of alterations of collagen fibers induced by the applied surgical procedure. It was noticed duplications and multiplications of the internal elastic lamina, as diffuse and nodular forms. Depletion of elastic fibers at the media was a lesion identified in most of the specimens. The depletion of reticulin fibers correlates with the accumulation of collagen fibers, which partially or completely replace the network in the media and intima. No correlation was found between changes in the reticulin network and the time between prelevation and buffered formalin fixation, the maximum time investigated being five days. The Orcein staining in the venous vessel evaluation panel may be a useful investigation.

Cells expressing POLG loss-of-function variants can decrease mtDNA copy number and increased growth rates in neighbouring A7r5 and HeLa cells

Mitochondrial disfunction promotes vascular disease, and mitochondrial diseases offer valuable insights into the pathological mechanisms of mitochondrial dysfunction. We previously described a patient cohort with variants in the mitochondrial DNA gamma polymerase (POLG) that were prone hypertension. We hypothesized that the POLG variants promote hypertrophy or hyperplasia of vascular smooth muscle cells in a way that stiffens or thickens blood vessels to explain the high rate of resistant hypertension in this cohort. The objective of this study was to assess the cellular phenotype of cells over-expressing POLG variants: pathogenic Y955C and variants of unknown significance; R964C, I1098N, Y1138C. We transiently expressed human FLAG-tagged POLG variants in rat A7r5 and HeLa cells for 2-4 days. Transfection effciency ranged from 20-30% in A7r5 and >60% in HeLa cells. POLG variants increased cell density by nuclear counting (20-60%) and growth rates measured by 48-72 h of live-cell imaging (Y955C > R964C > I1089N » Y1138C). Compared to wild-type, Y955C and R964C reduced mtDNA copy number (mCN) measured by droplet digital PCR by 10-20%. Imaging mtDNA nucleoids (anti-dsDNA) and the FLAG-tag showed that reduced mCN was not restricted to transfected cells. Addition of a P2A-T2A-nuclear-EGFP to the POLG constructs demonstrated that faster growth rates were not specific to transfected cells. Resting and oligomycin-stimulated mitochondrial membrane potential imaged with TMRM were unaffected by Y955C and R964C. Mitochondrial ROS (mitoSox) was similar between cultures transfected with Wild-type versus POLG variants and lower than levels stimulated by antimycin-A’s inhibition of complex III. Notably, we found a linear relationship between mCN and cell density that was not simply due to smaller cell size at higher densities. Using Hoescht-33342 staining to assess cell cycle, no clear difference in cell-cycle distribution was evident in unsynchronized cultures. We conclude that modest reduction of mCN induces a mitogenic effect, likely via a diffusible messenger that further reduces mCN in a cell population. The signalling mechanism of this phenomenon remains to be identified, but our results confirm that POLG malfunction can alter smooth muscle physiology in a way that could support pathogenic vascular remodelling and could promote enhanced growth in cancerous cells. Funded by the Natural Sciences and Research Council of Canada. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Morphological study of incompetent saphenous veins: apoptosis and ultrastructural changes of smooth muscle cells.

Varicose veins affect approximately 25% of people in industrialized countries. The study aimed at detecting apoptotic cells and histopathological changes in varicose vein walls. Patients (N.=41) with varicose veins and 30 control group patients were divided into two groups according to their age (younger and older than 50 years). Apoptosis was determined by the TUNEL assay, elastin and collagen IV expression by immunohistochemistry and ultrastructural changes by transmission electron microscopy. The results show that the number of apoptotic cells in the layers of varicose veins increased, in particular in a group of patients aged over 50 years. In the varicose veins as compared to control veins the elastic fibers were found to be thinner, more fragmented and disorderly arranged. Elastin and collagen IV expression was found to decline in the intima and the media of varicose veins in both age groups. Electron microscopy demonstrated hypertrophy and degeneration of smooth muscle cells. Furthermore, cells with ultrastructural feature of apoptosis were noted. In the disorganized and expanded extracellular matrix membrane-bound vesicles, ghost bodies with different size and electron density were observed. Ghost bodies seem to bud off from smooth muscle cells and are likely to be involved in extracellular matrix remodeling as they are seen in close contact with collagen fibers. The study demonstrates increase of apoptotic cells in the wall of varicose veins along with vein wall structural abnormalities including alterations of smooth muscle cells and decline of elastin and collagen IV expression.

Mechanotransduction-induced interplay between phospholamban and yes-activated protein induces smooth muscle cell hypertrophy

The gastrointestinal system is a hollow organ affected by fibrostenotic diseases that cause volumetric compromise of the lumen via smooth muscle hypertrophy and fibrosis. Many of the driving mechanisms remain unclear. Yes-associated protein-1 (YAP) is a critical mechanosensory transcriptional regulator that mediates cell hypertrophy in response to elevated extracellular rigidity. In the type 2 inflammatory disorder, eosinophilic esophagitis (EoE), phospholamban (PLN) can induce smooth muscle cell hypertrophy. We used EoE as a disease model for understanding a mechanistic pathway in which PLN and YAP interact in response to rigid extracellular substrate to induce smooth muscle cell hypertrophy. PLN induced YAP nuclear sequestration in a feed forward loop that caused increased cell size in response to rigid substrate. This mechanism of rigidity sensing may have previously unappreciated clinical implications for PLN expressing hollow systems such as the esophagus and heart.

Aging related decreases in NM myosin expression and contractility in a resistance vessel.

Introduction: Vasodilatation in response to NO is a fundamental response of the vasculature, and during aging, the vasculature is characterized by an increase in stiffness and decrease in sensitivity to NO mediated vasodilatation. Vascular tone is regulated by the activation of smooth muscle and nonmuscle (NM) myosin, which are regulated by the activities of myosin light chain kinase (MLCK) and MLC phosphatase. MLC phosphatase is a trimeric enzyme with a catalytic subunit, myosin targeting subunit (MYPT1) and 20kDa subunit of unknown function. Alternative mRNA splicing produces LZ+/LZ- MYPT1 isoforms and the relative expression of LZ+/LZ- MYPT1 determines the sensitivity to NO mediated vasodilatation. This study tested the hypothesis that aging is associated with changes in LZ+ MYPT1 and NM myosin expression, which alter vascular reactivity. Methods: We determined MYPT1 and NM myosin expression, force and the sensitivity of both endothelial dependent and endothelial independent relaxation in tertiary mesenteric arteries of young (6mo) and elderly (24mo) Fischer344 rats. Results: The data demonstrate that aging is associated with a decrease in both the expression of NM myosin and force, but LZ+ MYPT expression and the sensitivity to both endothelial dependent and independent vasodilatation did not change. Further, smooth muscle cell hypertrophy increases the thickness of the medial layer of smooth muscle with aging. Discussion: The reduction of NM myosin may represent an aging associated compensatory mechanism to normalize the stiffness of resistance vessels in response to the increase in media thickness observed during aging.

Dysfunctional mucociliary clearance in asthma and airway remodeling – New insights into an old topic

Bronchial asthma is a heterogeneous respiratory condition characterized by chronic airway inflammation, airway hyperresponsiveness and airway structural changes (known as remodeling). The clinical symptoms can be evoked by (non)specific triggers, and their intensity varies over time. In the past, treatment was mainly focusing on symptoms’ alleviation; in contrast modern treatment strategies target the underlying inflammation, even during asymptomatic periods. Components of airway remodeling include epithelial cell shedding and dysfunction, goblet cell hyperplasia, subepithelial matrix protein deposition, fibrosis, neoangiogenesis, airway smooth muscle cell hypertrophy and hyperplasia. Among the other important, and frequently forgotten aspects of airway remodeling, also loss of epithelial barrier integrity, immune defects in anti-infectious defence and mucociliary clearance (MCC) dysfunction should be pointed out. Mucociliary clearance represents one of the most important defence airway mechanisms. Several studies in asthmatics demonstrated various dysfunctions in MCC – e.g., ciliated cells displaying intracellular disorientation, abnormal cilia and cytoplasmic blebs. Moreover, excessive mucus production and persistent cough are one of the well-recognized features of severe asthma and are also associated with defects in MCC. Damaged airway epithelium and impaired function of the ciliary cells leads to MCC dysfunction resulting in higher susceptibility to infection and inflammation. Therefore, new strategies aimed on restoring the remodeling changes and MCC dysfunction could present a new therapeutic approach for the management of asthma and other chronic respiratory diseases.

Novel signaling axis of FHOD1-RNF213-Col1α/Col3α in the pathogenesis of hypertension-induced tunica media thickening

Hypertension-induced tunica media thickening (TMT) is the most important fundamental for the subsequent complications like stroke and cardiovascular diseases. Pathogenically, TMT originates from both vascular smooth muscle cells (VSMCs) hypertrophy due to synthesizing more amount of intracellular contractile proteins and excess secretion of extracellular matrix. However, what key molecules are involved in the pathogenesis of TMT is unknown. We hypothesize that formin homology 2 domain-containing protein 1 (FHOD1), an amply expressed mediator for assembly of thin actin filament in VSMCs, is a key regulator for the pathogenesis of TMT. In this study, we found that FHOD1 expression and its phosphorylation/activation were both upregulated in the arteries of three kinds of hypertensive rats. Ang-II induced actin filament formation and hypertrophy through activation and upregulation of FHOD1 in VSMCs. Active FHOD1-mediated actin filament assembly and secretions of collagen-1α/collagen-3α played crucial roles in Ang-II-induced VSMCs hypertrophy in vitro and hypertensive TMT in vivo. Proteomics demonstrated that activated FL-FHOD1 or its C-terminal diaphanous-autoregulatory domain significantly upregulated RNF213 (ring finger protein 213), a 591-kDa cytosolic E3 ubiquitin ligase with its loss-of-functional mutations being a susceptibility gene for Moyamoya disease which has prominent tunica media thinning in both intracranial and systemic arteries. Mechanistically, activated FHOD1 upregulated its downstream effector RNF213 independently of its classical pathway of decreasing G-actin/F-actin ratio, transcription, and translation, but dependently on its C-terminus-mediated stabilization of RNF213 protein. FHOD1-RNF213 signaling dramatically promoted collagen-1α/collagen-3α syntheses in VSMCs. Our results discovered a novel signaling axis of FHOD1-RNF213-collagen-1α/collagen-3α and its key role in the pathogenesis of hypertensive TMT.

Hibiscus attenuates renovascular hypertension-induced aortic remodeling dose dependently: the oxidative stress role and Ang II/cyclophilin A/ERK1/2 signaling.

Introduction: The high levels of angiotensin II (Ang II) can modify the vascular tone, enhance vascular smooth muscle cells (VSMCs) proliferation and hypertrophy and increase the inflammatory cellular infiltration into the vessel wall. The old herbal nonpharmacological agent, Hibiscus (HS) sabdariffa L has multiple cardioprotective impacts; thus, we investigated the role of HS extract in amelioration of renovascular hypertension (RVH)-induced aortic remodeling. Materials and methods: Thirty-five rats (7/group) were randomly allocated into 5 groups; group: I: Control-sham group, and RVH groups; II, III, IV, and V. The rats in RVH groups were subjected to the modified Goldblatt two-kidneys, one clip (2K1C) for induction of hypertension. In group: II, the rats were left untreated whereas in group III, IV, and V: RVH-rats were treated for 6weeks with low dose hibiscus (LDH), medium dose hibiscus (MDH), and high dose hibiscus (HDH) respectively. Results: We found that the augmented pro-contractile response of the aortic rings was ameliorated secondary to the in-vivo treatment with HS dose dependently. The cyclophilin A (CyPA) protein levels positively correlated with the vascular adhesion molecule-1 (VCAM-1) and ERK1/2, which, in turn, contribute to the reactive oxygen species (ROS) production. Daily HS intake modified aortic renovation by enhancing the antioxidant capacity, restraining hypertrophy and fibrosis, downregulation of the metastasis associated lung adenocarcinoma transcript (MALAT1), and cyclophilin A (CyPA)/ERK1/2 levels. Discussion: Adding to the multiple beneficial effects, HS aqueous extract was able to inhibit vascular smooth muscle cell proliferation induced by 2K1C model. Thus, adding more privilege for the utilization of the traditional herbal extracts to attenuate RVH-induced aortopathy.

Immunohistochemical basing of the pathogenesis equality of varicose vein transformation in varicocele and varicose veins of the lower extremities

Background. Varicocele as well as varicose veins of the lower extremities are quite widespread. To date, the mechanisms of variceal transformation remain not completely clear.Aim. To study the immunohistochemical profile in order to substantiate the common pathogenesis of varicose veins transformation in varicocele and varicose veins of the lower limbs; to confirm the key role of undifferentiated connective tissue dysplasia syndrome in the development of these diseases.Materials and methods. Vein wall fragments from 24 male patients aged 6–35 years old divided into the corresponding groups: group 1–12 patients with varicocele, group 2–12 patients with varicose veins of the lower limbs. Control group – 5 practically healthy men (age 16–32 years). Immunohistochemical study was performed with monoclonal antibodies to collagen types III, IV, α-SMA, fibronectin, laminin, MMP-2 and MMP-9, TGF-β1.Results and discussion. Histological and immunohistochemical studies of vein wall biopsy specimens in both groups revealed similar morphological changes, different from the control group. When assessing the expression level of α-SMA in both study groups, there was marked expression in the bundles of hypertrophic smooth muscle cells (in the zone of wall thickening where fibrosis was minimal) and weak expression in the bundles of smooth muscle cells “enmeshed” in connective tissue sleeves. Collagen type III showed weak expression in the subintimal zone and between the bundles of superficially located smooth muscle cells in both study groups. Expression of type IV collagen was detected in the areas of wall thickening and hypertrophy of smooth muscle cells. In both groups there was a pronounced expression of fibronectin in the most altered sections of the vein walls, especially in the middle layer, around the bundles of smooth muscle cells. There was marked expression of MMP-2 in all layers of the wall, and overexpression of MMP-9 in the areas of wall thinning (in the subintimal zone and muscular layer). TGF-β1 overexpression was also detected in vein biopsy specimens from both groups, predominantly in areas of thinning and pronounced intermuscular fibrosis.Conclusion. Taking into account the similarity of immunohistochemical manifestations in the vein walls in varicocele and varicose veins of the lower limbs we can speak about the common morphogenetic mechanisms of their remodeling. Thus, we consider it possible to combine various forms of varicosity into a single disease – varicose vein disease.

CEBPB/POU2F2 modulates Endothelin1 expression in prehypertensive SHR vascular smooth muscle cells.

The pathogenesis of hypertension is not fully understood; ET1 is involved in developing essential hypertension. ET1 can promote VSMC proliferation or hypertrophy through autocrine and paracrine effects. Proliferating smooth muscle cells in the aorta are "dedifferentiated" cells that cause increased arterial stiffness and remodeling. Male SHRs had higher aortic stiffness than normal control male WKY rats. Male SHR VSMCs expressed high levels of the ET1 gene, but endothelial cells did not. Therefore, it is necessary to understand the molecular mechanism of enhanced ET1 expression in SHR VSMCs. We identified POU2f2 and CEBPB as the main molecules that enhance ET1 expression in male SHR VSMCs. A promoter activity analysis confirmed that the enhancer region of the ET1 promoter in male SHR VSMCs was from -1309 to -1279 bp. POU2f2 and CEBPB exhibited an additive role in the enhancer region of the ET1 promoter. POU2f2 or CEBPB overexpression sufficiently increased ET1 expression, and co-transfection with the CEBPB and POU2f2 expression plasmids had additive effects on the activity of the ET1 promoter and ET1 secretion level of male WKY VSMCs. In addition, knockdown of POU2f2 also revealed that POU2f2 is necessary to enhance ET1 expression in SHR VSMCs. The enhancer region of the ET1 promoter is highly conserved in rats, mice, and humans. POU2f2 and CEBPB mRNA levels were significantly increased in remodeled human VMSCs. In conclusion, the novel regulation of POU2f2 and CEBPB in VSMCs will help us understand the pathogenesis of hypertension and support the development of future treatments for hypertension.

Transcription factors and potential therapeutic targets for pulmonary hypertension.

Pulmonary hypertension (PH) is a refractory and fatal disease characterized by excessive pulmonary arterial cell remodeling. Uncontrolled proliferation and hypertrophy of pulmonary arterial smooth muscle cells (PASMCs), dysfunction of pulmonary arterial endothelial cells (PAECs), and abnormal perivascular infiltration of immune cells result in pulmonary arterial remodeling, followed by increased pulmonary vascular resistance and pulmonary pressure. Although various drugs targeting nitric oxide, endothelin-1 and prostacyclin pathways have been used in clinical settings, the mortality of pulmonary hypertension remains high. Multiple molecular abnormalities have been implicated in pulmonary hypertension, changes in numerous transcription factors have been identified as key regulators in pulmonary hypertension, and a role for pulmonary vascular remodeling has been highlighted. This review consolidates evidence linking transcription factors and their molecular mechanisms, from pulmonary vascular intima PAECs, vascular media PASMCs, and pulmonary arterial adventitia fibroblasts to pulmonary inflammatory cells. These findings will improve the understanding of particularly interactions between transcription factor-mediated cellular signaling pathways and identify novel therapies for pulmonary hypertension.

Myocd regulates airway smooth muscle cell remodeling in response to chronic asthmatic injury.

Abnormal growth of airway smooth muscle cells is one of the key features in asthmatic airway remodeling, which is associated with asthma severity. The mechanisms underlying inappropriate airway smooth muscle cell growth in asthma remain largely unknown. Myocd has been reported to act as a key transcriptional coactivator in promoting airway-specific smooth muscle development in fetal lungs. Whether Myocd controls airway smooth muscle remodeling in asthma has not been investigated. Mice with lung mesenchyme-specific deletion of Myocd after lung development were generated, and a chronic asthma model was established by sensitizing and challenging the mice with ovalbumin for a prolonged period. Comparison of the asthmatic pathology between the Myocd knockout mice and the wild-type controls revealed that abrogation of Myocd mitigated airway smooth muscle cell hypertrophy and hyperplasia, accompanied by reduced peri-airway inflammation, decreased fibrillar collagen deposition on airway walls, and attenuation of abnormal mucin production in airway epithelial cells. Our study indicates that Myocd is a key transcriptional coactivator involved in asthma airway remodeling. Inhibition of Myocd in asthmatic airways may be an effective approach to breaking the vicious cycle of asthmatic progression, providing a novel strategy in treating severe and persistent asthma. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Polymorphisms in the Renin-Angiotensin System and eNOS Glu298Asp Genes Are Associated with Increased Risk for Essential Hypertension in a Mexican Population.

Essential hypertension is the result of modifiable and genetic factors, and it is associated with increased risk for atherothrombosis. Some polymorphisms are associated with hypertensive disease. The objective was to analyze the association between eNOS Glu298Asp, MTHR C677T, AGT M235T, AGT T174M, and A1166C and ACE I/D polymorphisms with essential hypertension in the Mexican population. In the present study, 224 patients with essential hypertension and 208 subjects without hypertension were included. The Glu298Asp, C677T, M235T, T174M, A1166C, and I/D polymorphisms were determined by the PCR-RFLP technique. We found statistical differences in age, gender, BMI, systolic and diastolic blood pressure, and total cholesterol between control and cases. However, we found no significant differences in HbA1c and triglycerides between both groups. We observed statistical significant differences in the genotype distribution of Glu298Asp (P = 0.001), I/D (P = 0.02), and M235T (P = 0.004) polymorphisms between both groups. In contrast, there were no differences related to distribution of genotypes of MTHFR C677T (P = 0.12), M174T (P = 0.46), and A1166C (P = 0.85) between cases and control groups. We identified that Glu298Asp, I/D, and M234T polymorphisms represented an increased risk for essential hypertension and those genetic variants could contribute to the presence of endothelial dysfunction and vasopressor effect, hyperplasia, and hypertrophy of smooth muscle cells, which had an impact for hypertension. In contrast, we found no association between C677C, M174T, and A1166C polymorphisms and hypertensive disease. We suggested that those genetic variants could be identified in individuals with high risk to avoid hypertension and thrombotic disease.

Expression profiles of circular RNAs and interaction networks of competing endogenous RNAs in neurogenic bladder of rats following suprasacral spinal cord injury.

Neurogenic bladder (NB) following suprasacral spinal cord injury (SSCI) is an interstitial disease with the structural remodeling of bladder tissue and matrix over-deposition. Circular RNAs (circRNAs) are involved in fibrotic disease development through their post-transcriptional regulatory functions. This study aimed to use transcriptome high-throughput sequencing to investigate the process of NB and bladder fibrosis after SSCI. Spinal cord transection at the T10-T11 level was used to construct the SSCI model in rats (10-week-old female Wistar rats, weighing 200 ± 20 g). The bladders were collected without (sham group) and with (SSCI 1-3 groups) NB status. Morphological examination was conducted to assess the extent of bladder fibrosis. Additionally, RNA sequencing was utilized to determine mRNAs and circRNAs expression patterns. The dynamic changes of differentially expressed mRNAs (DEMs) and circRNAs (DECs) in different periods of SSCI were further analyzed. Bladder weight, smooth muscle cell hypertrophy, and extracellular matrix gradually increased after SSCI. Compared with the sham group, 3,255 DEMs and 1,339 DECs, 3,449 DEMs and 1,324 DECs, 884 DEMs, and 1,151 DECs were detected in the SSCI 1-3 groups, respectively. Specifically, circRNA3621, circRNA0617, circRNA0586, and circRNA4426 were significant DECs common to SSCI 1-3 groups compared with the sham group. Moreover, Gene Ontology (GO) enrichment suggested that inflammatory and chronic inflammatory responses were the key events in NB progression following SSCI. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment associated with the "Chemokine signaling pathway", the "IL-17 signaling pathway", and the "TGF-beta signaling pathway" suggests their potential involvement in regulating biological processes. The circRNA-miRNA-mRNA interaction networks of DECs revealed rno-circ-2239 (micu2) as the largest node, indicating that the rno-circ-2239-miRNA-mRNA-mediated network may play a critical role in the pathogenesis of SSCI-induced NB. This study offers a comprehensive outlook on the possible roles of DEMs and DECs in bladder fibrosis and NB progression following SSCI. These findings have the potential to serve as novel biomarkers and therapeutic targets.

Downregulation of natriuretic peptide receptor-C in vascular smooth muscle cells from spontaneously hypertensive rats contributes to vascular remodeling

Hypertension is associated with vascular remodeling due to hyperproliferation and hypertrophy of vascular smooth muscle cells (VSMC). VSMC from several animal models of hypertensive rats including spontaneously hypertensive rats (SHR) exhibit hyperproliferation, hypertrophy and decreased expression of natriuretic peptide receptor-C (NPR-C). In addition, angiotensin II (Ang II) and growth factors that promotes vascular remodeling have also been shown to attenuate the expression of NPR-C in VSMC. The present study investigates the relationship between the decreased expression of NPR-C and vascular remodeling in SHR and the underlying molecular mechanisms. Aortic VSMC from SHR and their control Wistar Kyoto (WKY) rats were transfected with cDNA of NPR-C and used for the vascular remodeling studies. Transfection of VSMC with cDNA of NPR-C augmented the expression of NPR-C in both VSMC from SHR and WKY rats and resulted in the attenuation of hyperproliferation and hypertrophy of VSMC from SHR. The overexpression of NPR-C also resulted in the attenuation of increased expression of epidermal growth factor receptor (EGFR), platelet derived growth factor receptor (PDGFR), cell cycle proteins, cyclin D1, cyclin-dependent kinase 4 (Cdk4), phospho-retinoblastoma (pRb) and Giα-2 proteins, all these signaling molecules implicated in the hyperproliferation/hypertrophy of VSMC from SHR. In summary, these results indicate that augmenting the decreased expression of NPR-C in VSMC from SHR improves vascular remodeling by attenuating hyperproliferation and hypertrophy through decreasing the overexpression of several signaling molecules. It may be suggested that NPR-C plays a vasculoprotective role and that the downregulation of NPR-C contributes to the vascular remodeling in SHR.

Abstract P054: Loss Of The Smooth-muscle-cell-angiotensin Ii-sensitive Lncrna Leads To Smc Hypertrophic And Hypertensive Remodeling Due To Cell Cycle Dysregulation.

Vascular smooth muscle cells (SMC) responses to increased levels of Ang II during hypertensive remodeling included enhanced vasoconstriction and hypertrophy due to the enlargement of the SMC on the vessel wall. Hypertrophic SMC usually present defects in cell division and cell polyploidy. However, the molecular mechanisms controlling SMC hypertrophy and polyploidy vs. hyperplasia are still not fully understood. Long-non-coding-RNAs (LncRNAs) are epigenetic regulators of gene expression influencing biological processes, including cell division fidelity. We discovered a novel lncRNA decreased in dedifferentiated SMC, the SMC-Ang II-Sensitive (SAS) lncRNA, which expression is reduced in response to Ang-II in cultured SMC and the aorta of hypertensive mice, suggesting a role in mediating hypertension-induced SMC hypertrophy. Publicly available transcriptional datasets revealed that SAS is preferentially expressed in SMC-rich tissues, including the aorta and renal artery, in humans and mice. Yet, the functional relevance of SAS in SMC has never been investigated. Knockdown of SAS reduces proliferation and migration in SMC treated with Platelet-Derived Growth Factor (PDGF-BB). SAS knockdown was also associated with distinct SMC hypertrophic morphological changes, including enlargement in cell size and polynucleation in vitro. We have generated a SAS KO mouse, and aortas from these mice present a higher number of polynucleated medial SMC than their WT littermates. These data correlate with a cell cycle arrest in G1 and senescence phenotype that SAS deficient SMC present due to dysregulation in cyclins expression. Furthermore, SAS defective cells show mitochondria hyperfusion and increased oxygen consumption that correlates with the observed senescence and arrest on the G1/S checkpoint, and it is exacerbated by treatment with Ang-II. Interestingly, treatment with Losartan, an Ang-II receptor inhibitor, rescues SAS expression on Ang-II treated SMC and diminishes SMC hypertrophy. Together, these observations suggest that a decrease in SAS causes SMC hypertrophy due to defects in cell cycle completion. SAS is a potent regulator of SMC morphology and is required for proper cell division and mitochondria organization.

IL-13 Regulates Orai1 Expression in Human Bronchial Smooth Muscle Cells and Airway Remodeling in Asthma Mice Model via LncRNA H19.

BackgroundIncreased proliferation and hypertrophy of airway smooth muscle cells (ASMCs) contribute substantially to airway remodeling in asthma. Interleukin (IL)-13 regulates ASMC proliferation by increasing Orai1 expression, the pore-forming subunit of store-operated Ca2+ entry (SOCE). The underlying mechanisms of this effect are not fully understood.MethodsBioinformatic analysis identified an interaction between microRNA 93–5p (miR-93-5p) and long non-coding RNA (lncRNA) H19, and between miR-93-5p and Orai1. RNA interference was used to investigate H19 knockdown on IL-13-induced proliferation and migration of in vitro cultured human bronchial smooth muscle cells (hBSMCs). Functional relevance of H19 in airway inflammation and airway remodeling was investigated in murine models of acute and chronic asthma.ResultsIL-13 concentration-dependently increased the expression of H19 and Orai1 and decreased the expression of miR-93-5p in hBSMCs. H19 knockdown partly reversed the effects of IL-13 on the expression of miR-93-5p and Orai1 and attenuated the proliferation and migration of hBSMCs promoted by IL-13. IL-13-promoted expression of Orai1 was attenuated by miR-93-5p mimic and increased by miR-93-5p inhibitor. IL-13-promoted proliferation of hBSMCs was increased by miR-93-5p inhibitor but not affected by miR-93-5p mimic, whereas IL-13-promoted migration of hBSMCs was increased by miR-93-5p inhibitor and attenuated by miR-93-5p mimic. The inhibiting effect of H19 knockdown on IL-13-induced Orai1 expression and the proliferation and migration of hBSMCs was counteracted by miR-93-5p inhibitor but only marginally or not impacted by miR-93-5p mimic. The expression of H19 and Orai1 was higher in the lungs of asthmatic mice than in control mice. In asthmatic mice, H19 siRNA reduced Orai1 expression, inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition and smooth muscle mass in the lungs.ConclusionH19 may mediate the effects of IL-13 on Orai1 expression by inhibition of miR-93-5p in hBSMCs. H19 may be a therapeutic target for airway inflammation and airway remodeling.

Endothelin A (ETA) and Endothelin B (ETB) Receptor Subtypes Potentiate Epidermal Growth Factor (EGF)-Mediated Proliferation in Human Asthmatic Bronchial Airway Smooth Muscle.

BackgroundAsthma is a chronic disease characterized by chronic inflammation, reversible airway obstruction, airway hyperresponsiveness (AHR), and airway remodeling. One of the important features of asthma is airway remodeling, which plays a central role in airflow limitation. Airway remodeling involves numerous changes in the bronchial walls, including airway smooth muscle (ASM) cell hypertrophy and hyperplasia. Studies have shown that ASM hyperplasia in asthma is mediated by the increased production of mitogens. Endothelin-1 (ET-1) has been shown to induce proliferation and function as a co-mitogen in vascular and ASM. In patients with asthma, plasma and bronchoalveolar lavage fluid have been shown to have elevated ET-1 levels, which have been linked to airway remodeling and airflow obstruction in severe asthma. This study investigates the role of ET-1 in proliferation, the receptor subtype mediating its effect, and the signaling pathway.MethodologyNormal and asthmatic bronchial airway smooth muscle (BASM) cells were seeded into 5 × 103 cells/well. Cell proliferation was assayed using 5-bromo-2’-deoxyuridine (BrdU) incorporation. Confluent cells were treated with different concentrations of ET-1 in the presence or absence of the epidermal growth factor (EGF). Signaling pathways were explored using pretreatment of BASM with antagonists 15 minutes before ET-1/EGF stimulation.ResultsIn asthmatic BASM, ET-1 (0.1 nM) functions as a co-mitogen in the presence of EGF (10 nM), showing a significantly greater effect on asthmatic BASM proliferation compared with normal BASM. The ETA receptor antagonist BQ-123 (10-1,000 nM) significantly reduced the proliferative effect of ET-1/EGF on asthmatic BASM more than normal BASM. Moreover, the effect of ETB antagonist BQ-788 (1,000 nM) or pretreatment with the ETB agonist S6C (1-10 nM) followed by co-treatment with EGF in asthmatic BASM showed a small but significant decrease when pretreated with the inhibitor and increased with the agonist, thereby suggesting that the co-mitogenic effect of ET-1 is mainly via the activation of ETA receptors, with a small contribution by the ETB receptors in asthmatic BASM. Finally, pertussis toxin (PTX) pretreatment (25 and 50 ng/mL) showed that EGF and ET-1/EGF mitogenic and co-mitogenic signaling utilizes Gi/0-mediated transactivation by EGF and ET receptors, especially in asthmatic BASM, leading to the activation of Ras-ERK-PI3K pathways. Enhanced ERK and PI3K effects on proliferation suggested that these kinases modulate the co-mitogenic effect of ET-1 in asthmatic BASM. Enhanced cross-talk between ET and EGF receptors may be a potential mechanism contributing to airway remodeling in asthmatic BASM.ConclusionsET-1 enhances the mitogenic effect of EGF predominantly via the ETA receptor in asthmatic BASM with the activation of Ras, ERK, and PI3K. The cross-talk mechanism between ET and EGF receptors may be a potential therapeutic target to prevent the progression of airway remodeling in ASM in patients with asthma.

Experimental study of the specificity of morphological changes development in internal organs with prolonged exposure to coal-rock dust and sodium fluoride to the body

Introduction. Occupational diseases detected at occupational examinations - pneumoconiosis and fluorosis - are, as a rule, chronic, the initial stages of development are almost asymptomatic. Industrial dust affects only the respiratory organs. Specific sign of fluoride intoxication is a lesion of the musculoskeletal system. The information available in the literature on the systemic manifestations of these diseases is not numerous. In this regard, it is relevant to study the early morphological changes, the timing of their occurrence and the features of development, depending on the specificity of the production factor. The study aims to experimentally identify the specificity of the development of morphological changes in organs and tissues under prolonged exposure to harmful production factors: coal-rock dust and sodium fluoride. Materials and methods. The authors conducted studies on adult white male laboratory rats. Scientists studied the features of the development of morphological changes in the bronchopulmonary system, heart, liver and kidneys in the dynamics of the impact of production factors on experimental models of anthracosilicosis and chronic fluoride intoxication. For histological examination, specialists carried out organ sampling in animals after 1, 3, 6, 9, 12 weeks of the experime Results. Chronic exposure to coal-rock dust, as well as sodium fluoride, leads to the development of compensatory and adaptive changes in the internal organs in the early stages of the experiment before the formation of degenerative and fibroplastic disorders of the stromal and parenchymal components in the later stages. Inhalation of coal-rock dust creates in experimental animals by an early breakdown of the adaptive mechanisms of the respiratory system and heart muscle. There is a formation from the 6th week of the experiment of pneumosclerosis with the spread to the air-conducting structures, atrophy of the bronchial mucosa, degenerative changes in cardiomyocytes. Despite the early formation of stroma fibrosis, reparative processes restrain dystrophic cell changes in the liver and kidneys. All this develops by the 9th week of the experiment. The accumulation of sodium fluoride leads to the early formation of pronounced protein dystrophy of the liver and kidney parenchyma with the development of necrotic changes by the 6-9 weeks of the experiment. Disorders in the bronchopulmonary system before the 9th week of exposure are of the nature of immune inflammation with the subsequent development of degenerative changes in the air-conducting structures. The heart has moderate dystrophy throughout the experiment. Regardless of the influencing factor, changes in the vessels of the studied organs at the initial stages of the experiment lead to hypertrophy of smooth muscle cells of the media and intima, followed by the development of endotheliosis and hyalinosis. Limitations. The results of the histological examination are descriptive of pathomorphological changes in the bronchopulmonary system, heart muscle, liver and kidneys. We did not conduct a morphometry of various structures of the studied organs has not been carried out with subsequent statistical processing of the results obtained. In this regard, when studying the specifics of the development of morphological changes depending on the influencing harmful production factor, the compared indicators were the first morphological changes and the timing of their formation. Conclusions. The obtained results have theoretical and practical significance for the development of recommendations for timely preventive and organ-specific therapeutic measures in the premorbid period of the development of occupational diseases. Ethics. The researchers conducted maintenance, feeding and removal of animals from the experiment in accordance with the requirements of the Order of the Ministry of Health of the Russian Federation "On approval of the Rules of Good Laboratory Practice" (No. 199n of 01.04.2016), as well as the Guide for the Maintenance and Use of Laboratory Animals (Guide for the Care and Use of Laboratory Animals, 1996). Scientists received permission from the Bioethical Committee of the Research Institute of Complex Problems of Hygiene and Occupational Diseases to conduct the study.

Activation of the TGF-β1/Smads/α-SMA pathway is related to histological and functional changes in children with neurogenic bladder

This research is to investigate the expression of the TGF-β1/Smads/α-SMA pathway and its effect on bladder histology and function in children with neurogenic bladder (NB). The bladder specimens from 10 children with NB and 8 children with vesicoureteral junction obstruction were collected into the NB and control groups. The expression of TGF-β1, Smad2, Smad3, Smad4, Smad6, α-SMA, fibronectin, collagen I and collagen III in bladder tissues was detected. In addition, the histological characteristics of the bladder were evaluated. A preoperative urodynamic study was performed on all children with NB. We analysed the correlations among the expression of the marker protein a-SMA in myofibroblasts, effector cells of the pathway, and bladder function parameters. Compared with those in the control group, the expression of TGF-β1, Smad2, Smad3, Smad4, α-SMA, fibronectin, collagen I and collagen III was significantly increased in the NB group, while the expression of Smad6 was decreased (p < 0.01). HE and Masson staining in the NB group showed increased collagen levels and hypertrophy of smooth muscle cells. Children with NB had a low bladder volume ratio (BVR), low compliance (△C) and high maximum bladder pressure, low maximum flow rate, large postvoid residual volume, low bladder contraction index and low bladder voiding efficiency. The expression of α-SMA was negatively correlated with the BVR (r = − 0.7066, P = 0.0223) and △C (r = − 0.6516, P = 0.0412). We conclude that the TGF-β1/Smads/α-SMA pathway is activated in the bladder tissue of children with NB and may be involved in the processes causing histological and functional changes.