Muscle Fibroblasts Research Articles

Single-cell analysis reveals cellular heterogeneity, gene expression profiles, and pathway dynamics in acne vulgaris.

Acne vulgaris is a common dermatological condition, particularly in adolescents, and is associated with significant physical and psychological impacts. Its pathogenesis involves genetic factors, sebaceous gland dysfunction, inflammatory responses, and alterations in skin microbiota. Despite advancements in treatment, a comprehensive understanding of its cellular and molecular mechanisms remains limited, making therapeutic strategies challenging. Single-cell RNA sequencing (scRNA-seq) data from six acne vulgaris patients were obtained from the GEO database (GSE175817), filtered, and integrated. Differentially expressed genes (DEGs) were identified and subjected to functional enrichment analysis to explore the underlying pathogenesis. Gene set variation analysis (GSVA) was used to investigate metabolic pathway alterations, and ligand-receptor interactions were analyzed to examine cell-to-cell communication between lesional and non-lesional skin tissues. The integration of scRNA-seq data yielded the identification of eight distinct cell clusters, including endothelial cells, myeloid cells, lymphocytes, melanocytes, sebaceous gland cells, smooth muscle cells, keratinocytes and fibroblasts. The proportions of lymphoid and myeloid cells were found to be significantly different between the lesional and non-lesional sites. The differential expression of genes (DEGs) was found to be significantly specific to the different cell clusters. Abnormal intercellular communication was found to result in a substantial increase in the number and intensity of communications in the area of acne vulgaris lesions. Moreover, specific ligand-receptor pairs for SPP1 and IL6 associated with acne vulgaris were identified. Furthermore, the presence of specific alterations in metabolic pathways, including riboflavin metabolism, niacin metabolism, and lipoic acid metabolism, was observed. Our findings demonstrate the cellular heterogeneity and dysfunction of intercellular communication and metabolic signaling in the lesional skin tissues of patients with acne vulgaris. These findings have important implications for understanding the complex biological processes of acne vulgaris.

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

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

Smooth Muscle Cells and Fibroblasts in the Proximal Thoracic Aorta Exhibit Minor Differences Between Embryonic Origins in Angiotensin II-driven Transcriptional Alterations.

Thoracic aortopathy is influenced by angiotensin II (AngII) and exhibits regional heterogeneity with the proximal region of the thoracic aorta being susceptible. Smooth muscle cells (SMCs) and selected fibroblasts in this region are derived from two embryonic origins: second heart field (SHF) and cardiac neural crest (CNC). While our previous study revealed a critical role of SHF-derived cells in AngII-mediated aortopathy formation, the contribution of CNC-derived cells remains unclear. Mef2c-Cre R26R mT/mG mice were infused with AngII (1,000 ng/kg/min). Proximal thoracic aortas were harvested at baseline or after 3 days of infusion, representing the prepathological phase. Cells were sorted by origins using mGFP (SHF-derived) and mTomato (other origins, nSHF-derived) signals, respectively. After sorting cells by origin, single-cell RNA sequencing was performed and analyzed. Short-term AngII infusion induced significant transcriptomic changes in both SHF- and nSHF-derived SMCs, but differences between origins were modest. Fibroblast transcriptomes also underwent notable changes by AngII infusion, but differences between SHF and nSHF origins remained modest. Interestingly, AngII infusion resulted in the emergence of a new fibroblast sub-population. Several molecules related to the extracellular matrix, such as Eln and Col3a1 , were downregulated in SHF-derived fibroblasts compared to nSHF-derived fibroblasts in the new subcluster. Fibroblasts in the new subcluster exhibited lineage-specific differences in extracellular matrix-related genes; however, overall transcriptomic differences between origins in SMCs and fibroblasts in response to AngII were modest in the pre-pathological phase of AngII-induced thoracic aortopathy.

Single-cell RNA sequencing reveals the contribution of smooth muscle cells and endothelial cells to fibrosis in human atrial tissue with atrial fibrillation

AimsAtrial fibrillation (AF) has high mortality and morbidity rates. However, the intracellular molecular complexity of the atrial tissue of patients with AF has not been adequately assessed.Methods and resultsWe investigated the cellular heterogeneity of human atrial tissue and changes in differentially expressed genes between cells using single-cell RNA sequencing, fluorescence in situ hybridization, intercellular communication, and cell trajectory analysis. Using genome-wide association studies (GWAS) and proteomics, we discovered cell types enriched for AF susceptibility genes. We discovered eight different cell types, which were further subdivided into 23 subpopulations. In AF, the communication strength between smooth muscle cells (SMCs) and fibroblast (FB) 3 cells increased and the relevant signaling pathways were quite similar. Subpopulations of endothelial cells (ECs) are mainly involved in fibrosis through TXNDC5 and POSTN. AF susceptibility genes revealed by GWAS were especially enriched in neuronal and epicardial cells, FB3, and lymphoid (Lys) cells, whereas proteomic sequencing differential proteins were concentrated in FB3 cells and SMCs.ConclusionsThis study provides a cellular landscape based on the atrial tissue of patients with AF and highlights intercellular changes and differentially expressed genes that occur during the disease process. A thorough description of the cellular populations involved in AF will facilitate the identification of new cell-based interventional targets with direct functional significance for the treatment of human disease.

Analysis of the effectiveness of laparoscopic myomectomy using a standardized technique

BACKGROUND: Uterine fibroids are a benign monoclonal tumor arising from myometrial smooth muscle cells and fibroblasts with the deposition of extracellular matrix components in response to vascular injury. Diagnosis of uterine fibroids is steadily growing every year due to the introduction of new and accessible research methods. At the moment, the preferred organ-preserving surgical method for treating uterine fibroids is laparoscopic myomectomy, which allows preserving reproductive function. Considering the high risk of intra- and postoperative bleeding during surgery, the development and use of blood-saving technologies remains relevant. This article contains results of the effectiveness of the surgical technique without performing the stage of vessel clipping, which involves assessing the volume of intraoperative blood loss and the duration of the operation. AIM: The aim of this study was to analyze the effectiveness of using a standardized technique of laparoscopic myomectomy without uterine artery clipping. MATERIALS AND METHODS: This study included 77 patients with symptomatic uterine fibroids who underwent surgical treatment in Gynecological Department I with Operating Unit, The Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott (St. Petersburg, Russia). Implying an assessment of the volume of intraoperative blood loss and the duration of the operation. RESULTS: The average number of removed myomatous nodes was 2.2 ± 1.2 (from 1 to 11). The size of the removed fibroids averaged 5.1 ± 1.8 cm in diameter. At the same time, the minimum size of the remote node was 1.5 cm, and the maximum size was 15 cm. Intramural [International Federation of Gynecology and Obstetrics (FIGO) types 3 and 4] localization of myomatous nodes was found in 30 (17.6%) cases, intramural subserosal (FIGO type 5) in 45 (26.4%) cases, subserosal (FIGO type 6) in 54 (31.7%) cases, subserosal pedunculated (FIGO type 7) in 30 (17.6%) cases, and intramural submucosal and submucosal forms (FIGO types 0–2) in ten (5.8 %) cases. The average intraoperative blood loss was 187.7 ± 16.71 ml, average hemoglobin level in the postoperative period was 117.1 ± 13.15 g/l, with an initial level of 126 ± 12.1 g/l. The average duration of the operation was 95 ± 30.3 minutes, and the average bed-day was 8 ± 1.5. CONCLUSIONS: The data obtained allow for drawing a reasonable conclusion about the effectiveness and safety of the standardized technique of laparoscopic myomectomy, developed in Gynecological Department I with Operating Unit, The Research Institute of Obstetrics, Gynecology and Reproductology named after D.O. Ott (Saint Petersburg, Russia), and for recommending its widespread use.

CeO2/MnFe2O4 nanocomposite: Structural, magnetic, electrochemical and cytotoxicity properties

CeO2/MnFe2O4 nanocomposite: Structural, magnetic, electrochemical and cytotoxicity properties

Muscle fibroblasts and stem cells stimulate motor neurons in an age and exercise‐dependent manner

AbstractExercise preserves neuromuscular function in aging through unknown mechanisms. Skeletal muscle fibroblasts (FIB) and stem cells (MuSC) are abundant in skeletal muscle and reside close to neuromuscular junctions, but their relative roles in motor neuron maintenance remain undescribed. Using direct cocultures of embryonic rat motor neurons with either human MuSC or FIB, RNA sequencing revealed profound differential regulation of the motor neuron transcriptome, with FIB generally favoring neuron growth and cell migration and MuSC favoring production of ribosomes and translational machinery. Conditioned medium from FIB was superior to MuSC in preserving motor neurons and increasing their maturity. Lastly, we established the importance of donor age and exercise status and found an age‐related distortion of motor neuron and muscle cell interaction that was fully mitigated by lifelong physical activity. In conclusion, we show that human muscle FIB and MuSC synergistically stimulate the growth and viability of motor neurons, which is further amplified by regular exercise.

Histologic and immunohistochemical analysis of connective tissue changes in patients with intestinal sutures failure

Objective. To determine the role of connective tissue pathology in the development of intestinal suture failure in order to improve the results of treatment of patients with this complication. Materials and methods. The study included 45 patients with intestinal suture failure who were treated at the Shalimov National Research Center for Surgery and Transplantation of the National Academy of Medical Sciences of Ukraine in 2017–2023. Results. A comprehensive study of fragments of small and large intestine tissues revealed similar morphological changes in patients with phenotypic signs of undifferentiated connective tissue dysplasia and intestinal sutures failure. Immunohistochemical examination of tissues with monoclonal antibodies to α–smooth muscle actin in both groups of patients revealed uneven, focal expression in smooth muscle differentiation cells and fibroblasts; with monoclonal antibodies to type IV collagen – moderate positive expression in the basal membrane of blood vessels, in smooth muscle cells of the muscle layer of the vessel wall, in areas of connective tissue, which meant pathological remodeling of connective tissue. Conclusions. The similar results of histological and immunohistochemical studies in patients with signs of undifferentiated connective tissue dysplasia and intestinal sutures failure confirm the influence of connective tissue pathology on the development of this complication.

Non-invasive assessment of IgA nephropathy severity with [18F]AlF-NOTA-FAPI-04 PET/CT imaging.

Renal biopsy plays a crucial role in diagnosing and assessing the severity of immunoglobulin A nephropathy (IgAN), despite being an invasive procedure with potential risk of failure. Our study focused on evaluating the capability of [18F]AlF-NOTA-FAPI-04 PET/CT in identifying the extent of pathological alterations in IgAN. Twenty patients (13 males and 7 females; mean age, 44±16 years) with newly diagnosed primary IgAN and 10 patients (7 males and 3 females; mean age, 51±4 years) without known renal disease underwent [18F]AlF-NOTA-FAPI-04 PET/CT imaging. Kidney tissues from biopsies were stained with various techniques and examined using immunofluorescence. The Oxford classification was used to evaluate pathological indicators. Immunohistochemical staining was conducted to assess α-smooth muscle actin (αSMA) and fibroblast activation protein (FAP) expression. Renal FAPI uptake measured by positron emission tomography/computed tomography (PET/CT) (maximum and mean standardized uptake value, SUVmax and SUVmean) was correlated with histological findings. The renal parenchymal FAPI uptake was significantly higher in IgAN patients compared with control patients (SUVmax=3.9±1.3 vs 1.9±0.4, SUVmean=3.6±1.2 vs 1.5±0.4; all P<.001). We identified a significant difference in renal parenchymal FAPI uptake among the various categories of the Oxford classification. Correlation analysis revealed a positive association between SUVmax and interstitial fibrosis and tubular atrophy, as well as tubulointerstitial inflammation scores in scarred cortex and non-scarred cortex (r=0.637, 0.593 and 0.491, all P<.05), Similar associations were observed between SUVmean and these scores (r=0.641, 0.592 and 0.479, all P<.05). Furthermore, significant positive correlations were observed between SUVmax or SUVmean and the staining scores for glomerular αSMA and FAP, as well as for tubulointerstitial αSMA and FAP (all P<.01). [18F]AlF-NOTA-FAPI-04 PET/CT imaging offers IgAN patients a non-invasive and reproducible auxiliary modality to monitor disease progression.

The role of cellular senescence in aortic dissection

Abstract Background Aortic dissection (AD) is a catastrophic disease with high mortality. Survived patients frequently suffer from serious complications due to progressive destruction of the aortic walls. Recently we have reported that cell proliferation precedes the inflammatory response which is important in AD development and progression. Since cell proliferation promotes cellular senescence that can induce inflammatory response through SASP (senescence-associated secretary phenotype), we hypothesized that cellular senescence plays a critical role in AD pathogenesis. Purpose To investigate if cellular senescence contributes to AD pathogenesis in mouse AD model. Methods and Results A mouse AD model was created by the continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII) for 14days. BAPN+AngII infusion induced senescence markers and senescent cells in mouse AD model. Senescent cells, as demonstrated by the expression of senescence-associated beta-galactosidase, were evident in intimal endothelial cells, medial smooth muscle cells, adventitial macrophages, and fibroblasts. Rapamycin, an inhibitor of mTOR pathway, suppressed the expression of senescent cells on the aortic tissue and the senescent marker protein expression. To examine the role of cellular senescence in AD, we orally administrated ABT263 known as "senolytics" that eliminates senescent cells. ABT263 treatment prevented cellular senescence in mouse AD model. The AD mortality of ABT263 group was 35%, which was lower than that of vehicle group (66.7%, P &amp;lt; 0.05 by log-rank test). The severity of AD, as assessed by the lesion length in vehicle group was 33.2 ± 3.1mm, whereas that in ABT263 group was 24.6 ± 1.8mm (P &amp;lt; 0.05). Transcriptome analysis revealed that ABT263 treatment suppressed the immune and inflammatory response in the aorta before AD onset. Quantitative RT-PCR confirmed that ABT263 treatment prevented the induction of p21Cip1, interleukin-6, several chemokines and M1 macrophage marker CD80 and CD86. It is known that Jnk activation induces SASP and accelerates cellular senescence. Western blotting confirmed that ABT263 reduced the ratio of pJnk to total Jnk, which was induced by BAPN + AngⅡ. Moreover, aortic smooth muscle cells（SMCs）remained contractile phenotype in ABT263 group, whereas BAPN+AngII reduced that phenotype in vehicle group. Conclusions Cell proliferation via mTOR pathway causes cellular senescence in mouse AD model. Jnk activation was confirmed in mouse AD model. Cellular senescence contributes to AD progression and death associated with inflammatory responses including SASP, the differentiation to M1 macrophage, and the phenotype change of SMCs.Cellular senescence represents a potential predictor and a therapeutic target for AD.

Comprehensive study of CeO2/CuFe2O4 nanocomposites: Structural, EPR, magnetic, electrochemical, and cytotoxicity properties

Comprehensive study of CeO2/CuFe2O4 nanocomposites: Structural, EPR, magnetic, electrochemical, and cytotoxicity properties

ADAMTS7 Promotes Smooth Muscle Foam Cell Expansion in Atherosclerosis.

Human genetic studies have repeatedly associated ADAMTS7 with atherosclerotic cardiovascular disease. Subsequent investigations in mice demonstrated that ADAMTS7 is proatherogenic and induced in response to vascular injury and that the proatherogenicity of ADAMTS7, a secreted protein, is due to its catalytic activity. However, the cell-specific mechanisms governing ADAMTS7 proatherogenicity remain unclear. To determine which vascular cell types express ADAMTS7, we interrogated single-cell RNA sequencing of human carotid atherosclerosis and found ADAMTS7 expression in smooth muscle cells (SMCs), endothelial cells (ECs), and fibroblasts. We subsequently created SMC- and EC-specific Adamts7 conditional knockout and transgenic mice. Conditional knockout of Adamts7 in either cell type is insufficient to reduce atherosclerosis, whereas transgenic induction in either cell type increases atherosclerosis. In SMC transgenic mice, this increase coincides with an expansion of lipid-laden SMC foam cells and decreased fibrous cap formation. RNA-sequencing in SMCs revealed an upregulation of lipid uptake genes typically assigned to macrophages. Subsequent experiments demonstrated that ADAMTS7 increases SMC oxLDL uptake through increased CD36 levels. Furthermore, Cd36 expression is increased due to increased levels of PU.1, a transcription factor typically associated with myeloid fate determination. In summary, Adamts7 expression in either SMCs or ECs promotes SMC foam cell formation and atherosclerosis. In SMCs, ADAMTS7 promotes oxLDL uptake via increased PU.1 and Cd36 expression, thereby increasing SMC foam cell formation and atherosclerosis.

Abstract P205: Single-nucleus Sequencing Reveals Endothelial Cell-specific Dysregulation in the Kidney in Multiple Models of Hypertension

The kidney plays a crucial role in the onset and progression of hypertension. To investigate the roles of different renal cell types in hypertension, we applied single-nucleus sequencing and spatial transcriptome sequencing to kidney samples from three well-established hypertension models: C57BL/6 mice treated with Ang II, the Dahl salt-sensitive (SS) rat on high-salt diets, and the spontaneously hypertensive rat (SHR), along with their respective controls including Sprague-Dawley (SD) and Wistar Kyoto (WKY) rats. Our dataset comprised 179,637 nuclei from 24 samples across 12 experimental conditions, identifying 17 major cell types including various epithelial cells, endothelial cells, vascular smooth muscle cells, fibroblasts, and immune cells. At baseline, differentially expressed genes between the SS and SD groups were specifically enriched in endothelial cell pathways related to vascular development. This included expression deficiencies in genes involved in angiogenesis in SS rats, such as Arhgap24 and Nox4. Compensatory expression changes in these genes were observed in the SS rats after a high-salt diet and in 26-week-old SHR, but not in their respective controls. These genes were also associated with multiple blood pressure-associated single-nucleotide polymorphisms (SNPs). Furthermore, changes in endothelial cell communication were most prominent upon stimuli, with impaired PTPRM (Protein Tyrosine Phosphatase Receptor Type M) signaling being a robust feature in hypertension models, involving angiogenic endothelial cells in the SS model and proliferating capillary endothelial cells in the SHR model. Our study highlights the critical role of renal endothelial cell angiogenic dysfunction in the pathogenesis of hypertension and suggests a link between specific renal endothelial cell subtype dysregulation and hypertension development.

Single-cell analysis reveals the implication of vascular endothelial cell-intrinsic ANGPT2 in human intracranial aneurysm.

While previous single-cell RNA sequencing (scRNA-seq) studies have attempted to dissect intracranial aneurysm (IA), the primary molecular mechanism for IA pathogenesis remains unknown. Here, we uncovered the alterations of cellular compositions, especially the transcriptome changes of vascular endothelial cells (ECs), in human IA. We performed scRNA-seq to compare the cell atlas of sporadic IA and the control artery. The transcriptomes of 43,462 cells were profiled for further analysis. In general, IA had increased immune cells (T/NK cells, B cells, myeloid cells, mast cells, neutrophils) and fewer vascular cells (ECs, vascular smooth muscle cells and fibroblasts). Based on the obtained high-quantity and high-quality EC data, we found genes associated with angiogenesis in ECs from IA patients. By EC-specific expression of candidate genes in vivo, we observed the involvement of angpt2a in causing cerebral vascular abnormality. Furthermore, an IA zebrafish model mimicking the main features of human IA was generated through targeting pdgfrb gene, and knockdown of angpt2a alleviated the vascular dilation in the IA zebrafish model. By performing a landscape view of the single-cell transcriptomes of IA and the control artery, we contribute to a deeper understanding of the cellular composition and the molecular changes of ECs in IA. The implication of angiogenic regulator ANGPT2 in IA formation and progression, provides a novel potential therapeutical target for IA interventions.

Potential of diagnostic electron microscopy of calcification, pathological neovascularization and elastolysis in combination with phenotyping of cell populations in large arteries

Aim. To determine the potential of diagnostic electron microscopy of intraplaque processes (severity of lipid damage, fibrous cap thickness and condition, severity of pathological neovascularization, presence, nature and severity of calcification, ratio and distribution of various cell populations).Material and methods. The study objects were plaques removed during endar­terectomy from the human carotid artery and segments of the human internal mammary artery removed during coronary bypass surgery. Whole specimens were subjected to chemical fixation, staining with heavy metal salts, embedding in epoxy resin followed by layer-by-layer grinding, polishing, contrasting, visualization using back-scattered electron scanning electron microscopy and three-dimensional reconstruction with color mapping (modified EM-BSEM).Results. The use of a modified EM-BSEM made it possible to: 1) visualize the fibrous cap thickness and assess the extracellular matrix; 2) analyze the neointimal lipid distribution; 3) perform three-dimensional reconstruction and analyze the microenvironment of calcifications of various sizes; 4) visualize endothelial cells, defects in interendothelial contacts and the basement membrane of neointimal capillaries with their subsequent three-dimensional reconstruction; 5) perform an analysis of age-dependent defects in the basement membrane and internal elastic membrane of the internal mammary artery. The resolution of the obtained images was significantly superior to intravascular imaging methods (intravascular ultrasound and optical coherence tomography), allowing additional assessment of capillary fluidity, the degree of calcification encapsulation and the condition of elastic fibers. Three-dimensional reconstruction of calcifications, neointimal capillaries and elastic fibers made it possible to assess their spatial density and heterogeneity. Simultaneously with the identification and assessment of these histological structures, objective phenotyping of cell populations was performed, which made it possible to isolate macrophages and foam cells, vascular smooth muscle cells, fibroblasts and endothelial cells in atherosclerotic plaques and automatically identify them through color mapping determined by their electronic contrast distribution signatures.Conclusion. The modified EM-BSEM method allows for universal electron microscopic diagnosis of atherosclerotic and elastolytic lesions of large arteries with high information content about vascular remodeling and high accuracy. Electronic contrast distribution signatures unique for each cell population indicate the possibility of their automated phenotyping using specialized neural network algorithms.

The Role of Progenitor Cells in the Pathogenesis of Arteriosclerosis

The increasing incidence of arteriosclerosis has become a significant global health burden. Arteriosclerosis is characterized by the thickening and hardening of arterial walls, which can lead to the narrowing or complete blockage of blood vessels. However, the pathogenesis of the disease remains incompletely understood. Recent research has shown that stem and progenitor cells found in the bone marrow and local vessel walls play a role in the development of arteriosclerosis by differentiating into various types of vascular cells, including endothelial cells, smooth muscle cells, fibroblasts, and inflammatory cells. This review aims to provide a comprehensive understanding of the role of stem and progenitor cells in the pathogenesis of arteriosclerosis, shedding light on the underlying mechanisms and potential therapeutic approaches for this disease.

Chitinase‑3 like‑protein‑1: A potential predictor of cardiovascular disease (Review).

Chitinase‑3 like‑protein‑1 (CHI3L1), a glycoprotein belonging to the glycoside hydrolase family 18, binds to chitin; however, this protein lacks chitinase activity. Although CHI3L1 is not an enzyme capable of degrading chitin, it plays significant roles in abnormal glucose and lipid metabolism, indicating its involvement in metabolic disorders. In addition, CHI3L1 is considered a key player in inflammatory diseases, with clinical data suggesting its potential as a predictor of cardiovascular disease. CHI3L1 regulates the inflammatory response of various cell types, including macrophages, vascular smooth muscle cells and fibroblasts. In addition, CHI3L1 participates in vascular remodeling and fibrosis, contributing to the pathogenesis of cardiovascular disease. At present, research is focused on elucidating the role of CHI3L1 in cardiovascular disease. The present systematic review was conducted to comprehensively evaluate the effects of CHI3L1 on cardiovascular cells, and determine the potential implications in the occurrence and progression of cardiovascular disease. The present study may further the understanding of the involvement of CHI3L1 in cardiovascular pathology, demonstrating its potential as a therapeutic target or biomarker in the management of cardiovascular disease.

Exosomes derived from gastric cancer cells promote phenotypic transformation of hepatic stellate cells and affect the malignant behavior of gastric cancer cells.

This study aimed to evaluate the effect of exosomes derived from gastric cancer cells on the phenotypic transformation of hepatic stellate cells (HSCs) and the effect of HSC activation on the malignant behavior of gastric cancer cells, including its molecular mechanism. Exosomes derived from the human gastric adenocarcinoma cell line AGS were extracted and purified by polymer precipitation and ultrafiltration, respectively. The exosomes' morphologic characteristics were observed using transmission electron microscopy, particle size was determined through nanoparticle-tracking analysis, and marker proteins were detected using western blotting. Exosome uptake by LX-2 HSCs was observed through fluorescence-based tracing. Reverse transcription quantitative PCR (RT-qPCR) was used to detect the messenger RNA (mRNA) expression of alpha-smooth muscle actin (α-SMA) and fibroblast activation protein (FAP). Using functional assays, the effects of LX-2 HSC activation on the biological behavior of malignant gastric cancer cells were evaluated. The effects of LX-2 HSC activation on the protein expression of epithelial-mesenchymal transition (EMT)-related genes and β-catenin were evaluated via western blotting. The extracted particles conformed to the definitions of exosomes and were thus considered gastric cancer cell-derived exosomes. Fluorescence-based tracing successfully demonstrated that exosomes were enriched in LX-2 HSCs. RT-qPCR revealed that the mRNA expression of the cancer-associated fibroblast markers α-SMA and FAP was significantly increased. LX-2 HSC activation considerably enhanced gastric cancer cell proliferation, invasion, and migration. Western blotting showed that the expression of the EMT-related epithelial marker E-cadherin was significantly downregulated, whereas the expression of interstitial markers (N-cadherin and vimentin) and β-catenin was remarkably upregulated in gastric cancer cells. Exosomes derived from gastric cancer cells promoted phenotypic transformation of HSCs and activated HSCs to become tumor-associated fibroblasts. Gastric cancer cell-derived cells significantly enhanced gastric cancer cell proliferation, invasion, and migration after HSC activation, which may promote EMT of gastric cancer cells through the Wnt/β-catenin pathway.

IL-17 signaling pathway: A potential therapeutic target for reducing skeletal muscle inflammation

The interleukin-17 (IL-17) signaling pathway is intricately linked with immunity and inflammation; however, the association between the IL-17 signaling pathway and skeletal muscle inflammation remains poorly understood. The study aims to investigate the role of the IL-17 signaling pathway in skeletal muscle inflammation and to evaluate the therapeutic potential of anti-IL-17 antibodies in reducing muscle inflammation. A skeletal muscle inflammation model was induced by cardiotoxin (CTX) injection in C57BL6/J mice. Following treatment with an anti-IL-17 antibody, we conducted a comprehensive analysis integrating single-cell RNA sequencing (scRNA-seq), bioinformatics, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and Western blot techniques to elucidate underlying mechanisms. scRNA-seq analysis revealed a significant increase in neutrophil numbers and activity in inflamed skeletal muscle compared to other cell types, including macrophages, T cells, B cells, endothelial cells, fast muscle cells, fibroblasts, and skeletal muscle satellite cells. The top 30 differentially expressed genes within neutrophils, along with 55 chemokines, were predominantly enriched in the IL-17 signaling pathway. Moreover, the IL-17 signaling pathway exhibited heightened expression in inflamed skeletal muscle, particularly within neutrophils. Treatment with anti-IL-17 antibody resulted in the suppression of IL-17 signaling pathway expression, accompanied by reduced levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, as well as decreased numbers and activity of Ly6g+/Mpo+ neutrophils compared to CTX-induced skeletal muscle inflammation. Our findings suggest that the IL-17 signaling pathway plays a crucial role in promoting inflammation within skeletal muscle. Targeting this pathway may hold promise as a therapeutic strategy for ameliorating the inflammatory micro-environment and reducing cytokine production.

O-264 Profiling Tumor-Initiating Cells in Uterine Leiomyoma through Single-Cell Multi-omics

Abstract Study question What are the molecular and cellular features that contribute to the transformation of myometrial stem cells into tumor-initiating cells within uterine leiomyoma? Summary answer Transformative changes in differentiation and genetic processes, in a distinct subset of M/LM cells drives their progression into a tumorigenic state. What is known already Uterine leiomyomas (LM), which are benign smooth muscle-derived tumours of myometrium, impact approximately 75% of women, causing significant physical and psychological challenges and imposing substantial healthcare costs. The widespread consensus postulates a monoclonal origin for LM, implying their derivation from a dysregulated single multipotent stem cell that could give rise to tumor-initiating cells (TICs). While previous studies have shown cellular heterogeneity in both myometrium (M) and LM, the precise identity of the originating cells is unknown. Study design, size, duration Prospective, observational, and biomedical study conducted at Hospital La Fe (Valencia, Spain) for one year. Eight sample pairs of LM and M underwent single-nuclei RNAseq (snRNA-seq; n = 16) and single-cell proteomic (scP; n = 16) analyses, to generate a detailed transcriptomic and proteomic map decoupled from cell type, state, and spatial location. We further employed single-cell RNA velocity inference for differentiation trajectory [BR1] analysis of mesenchymal cells, followed by the identification of potential driver genes in LM tumorigenesis. Participants/materials, setting, methods Upon obtaining informed consent, we procured LM and M samples from eight patients aged 35-50 undergoing hysterectomies. Part of these samples were preserved in paraffin for spatial transcriptomics utilizing VISIUM (10x Genomics). The remaining tissues were dissociated into single-cell suspensions and underwent scRNA-seq and scP using Chromium Controller and Orbitrap Eclipse Tribid mass spectrometry, respectively. The analysis of the collected data was carried out using publicly accessible R/Python tools. Main results and the role of chance Analysis of snRNAseq (∼52,000 cells) revealed similar cellular compositions in M and LM, including endothelial, perivascular, smooth muscle cells (SMC), fibroblasts, and immune cells. Further trajectory analysis unveiled a subset of myometrial cells with potential as TICs, exhibiting reduced expression of hormone receptors like PGR. Analysis of these cells [BR1] suggested differentiation into two distinct cell types -fibroblasts and SMCs- with elevated hormone expression over pseudotime. Differential analysis between M and LM also showed a dysregulated transcriptomic profile in the TICs within the tumor, as evidenced by upregulation of RAD51B and HMGA2 and downregulation PGR among other genes. These genes are indicative markers, underscoring their significant roles in the tumorigenesis of LM by influencing hormone response and disrupting DNA repair mechanisms. Spatial transcriptomic analysis confirmed these findings and suggested that the distribution of TICs could be ubiquitous, since the expression of potential myometrial-stem markers, was markedly increased only on certain spots within the tissue across both LM and M. Lastly, scProt profiling (∼5,000 cells) also allowed the identification of putative TICs, which showed upregulation in LM of specific proteins involved in replication, transcription, and translation. Limitations, reasons for caution Our study sets the basis for TICs isolation in LM, yet functional validation studies need to be performed to address the clinical potential of our findings. Further studies including more patients, and addressing racial disparities will help to generalize these findings to a broader population. Wider implications of the findings Our findings indicate the presence of a particular subset of M/LM cells whose changes in differentiation path and genetic processes seem to drive the transformation of these cells into a tumorigenic state to develop LM. Targeting these markers might show promise for effectively treating these tumors. Trial registration number NCT04214457