Versican Promotes Cardiomyocyte Proliferation and Cardiac Repair.

BACKGROUND: The adult mammalian heart is incapable of regeneration, whereas a transient regenerative capacity is maintained in the neonatal heart, primarily through the proliferation of preexisting cardiomyocytes. Neonatal heart regeneration after myocardial injury is accompanied by an expansion of cardiac fibroblasts and compositional changes in the extracellular matrix. Whether and how these changes influence cardiomyocyte proliferation and heart regeneration remains to be investigated. METHODS: We used apical resection and myocardial infarction surgical models in neonatal and adult mice to investigate extracellular matrix components involved in heart regeneration after injury. Single-cell RNA sequencing and liquid chromatography-mass spectrometry analyses were used for versican identification. Cardiac fibroblast-specific Vcan deletion was achieved using the mouse strains Col1a2-2A-CreER and Vcanfl/fl. Molecular signaling pathways related to the effects of versican were assessed through Western blot, immunostaining, and quantitative reverse transcription polymerase chain reaction. Cardiac fibrosis and heart function were evaluated by Masson trichrome staining and echocardiography, respectively. RESULTS: Versican, a cardiac fibroblast-derived extracellular matrix component, was upregulated after neonatal myocardial injury and promoted cardiomyocyte proliferation. Conditional knockout of Vcan in cardiac fibroblasts decreased cardiomyocyte proliferation and impaired neonatal heart regeneration. In adult mice, intramyocardial injection of versican after myocardial infarction enhanced cardiomyocyte proliferation, reduced fibrosis, and improved cardiac function. Furthermore, versican augmented the proliferation of human induced pluripotent stem cell-derived cardiomyocytes. Mechanistically, versican activated integrin ß1 and downstream signaling molecules, including ERK1/2 and Akt, thereby promoting cardiomyocyte proliferation and cardiac repair. CONCLUSIONS: Our study identifies versican as a cardiac fibroblast-derived pro-proliferative proteoglycan and clarifies the role of versican in promoting adult cardiac repair. These findings highlight its potential as a therapeutic factor for ischemic heart diseases.

Proteomic Atlas of Atherosclerosis: The Contribution of Proteoglycans to Sex Differences, Plaque Phenotypes, and Outcomes.

BACKGROUND: Using proteomics, we aimed to reveal molecular types of human atherosclerotic lesions and study their associations with histology, imaging, and cardiovascular outcomes. METHODS: Two hundred nineteen carotid endarterectomy samples were procured from 120 patients. A sequential protein extraction protocol was employed in conjunction with multiplexed, discovery proteomics. To focus on extracellular proteins, parallel reaction monitoring was employed for targeted proteomics. Proteomic signatures were integrated with bulk, single-cell, and spatial RNA-sequencing data, and validated in 200 patients from the Athero-Express Biobank study. RESULTS: This extensive proteomics analysis identified plaque inflammation and calcification signatures, which were inversely correlated and validated using targeted proteomics. The inflammation signature was characterized by the presence of neutrophil-derived proteins, such as S100A8/9 (calprotectin) and myeloperoxidase, whereas the calcification signature included fetuin-A, osteopontin, and gamma-carboxylated proteins. The proteomics data also revealed sex differences in atherosclerosis, with large-aggregating proteoglycans versican and aggrecan being more abundant in females and exhibiting an inverse correlation with estradiol levels. The integration of RNA-sequencing data attributed the inflammation signature predominantly to neutrophils and macrophages, and the calcification and sex signatures to smooth muscle cells, except for certain plasma proteins that were not expressed but retained in plaques, such as fetuin-A. Dimensionality reduction and machine learning techniques were applied to identify 4 distinct plaque phenotypes based on proteomics data. A protein signature of 4 key proteins (calponin, protein C, serpin H1, and versican) predicted future cardiovascular mortality with an area under the curve of 75% and 67.5% in the discovery and validation cohort, respectively, surpassing the prognostic performance of imaging and histology. CONCLUSIONS: Plaque proteomics redefined clinically relevant patient groups with distinct outcomes, identifying subgroups of male and female patients with elevated risk of future cardiovascular events.

The C-terminal domains of ADAMTS1 contain exosites involved in its proteoglycanase activity.

A disintegrin-like and metalloproteinase with thrombospondin type 1 motifs (ADAMTS1) is a protease involved in fertilization, cancer, cardiovascular development, and thoracic aneurysms. Proteoglycans such as versican and aggrecan have been identified as ADAMTS1 substrates, and Adamts1 ablation in mice typically results in versican accumulation; however, previous qualitative studies have suggested that ADAMTS1 proteoglycanase activity is weaker than that of other family members such as ADAMTS4 and ADAMTS5. Here, we investigated the functional determinants of ADAMTS1 proteoglycanase activity. We found that ADAMTS1 versicanase activity is approximately 1000-fold lower than ADAMTS5 and 50-fold lower than ADAMTS4 with a kinetic constant (kcat/Km) of 3.6 × 103 M-1 s-1 against full-length versican. Studies on domain-deletion variants identified the spacer and cysteine-rich domains as major determinants of ADAMTS1 versicanase activity. Additionally, we confirmed that these C-terminal domains are involved in the proteolysis of aggrecan as well as biglycan, a small leucine-rich proteoglycan. Glutamine scanning mutagenesis of exposed positively charged residues on the spacer domain loops and loop substitution with ADAMTS4 identified clusters of substrate-binding residues (exosites) in ß3-ß4 (R756Q/R759Q/R762Q), ß9-ß10 (residues 828-835), and ß6-ß7 (K795Q) loops. This study provides a mechanistic foundation for understanding the interactions between ADAMTS1 and its proteoglycan substrates and paves the way for development of selective exosite modulators of ADAMTS1 proteoglycanase activity.

Expression of versican isoforms V0/V1 by pancreatic cancer associated fibroblasts increases fibroblast proliferation.

BACKGROUND: Versican is a large extracellular matrix (ECM) proteoglycan with four isoforms V0-3. Elevated V0/V1 levels in breast cancer and glioma regulate cell migration and proliferation, but the role of versican in pancreatic ductal adenocarcinoma (PDAC) remains unclear. METHODS: In this study, we evaluated the expression levels of versican isoforms, as well as their cellular source and interacting partners, in vivo, in human and mouse primary and metastatic PDAC tumours and in vitro, in pancreatic tumour cells and fibroblasts using immunostaining, confocal microscopy and qPCR techniques. We also investigated the effect of versican expression on fibroblast proliferation and migration using genetic and pharmacological approaches. RESULTS: We found that versican V0/V1 is highly expressed by cancer-associated fibroblasts (CAFs) in mouse and human primary and metastatic PDAC tumours. Our data also show that exposing fibroblasts to tumour-conditioned media upregulates V0 and V1 expressions, while Verbascoside (a CD44 inhibitor) downregulates V0/V1 expression. Importantly, V0/V1 knockdown significantly inhibits fibroblast proliferation. Mechanistically, we found that inhibiting hyaluronan synthesis does not affect versican co-localisation with CD44 in fibroblasts. CONCLUSION: CAFs express high levels of versican V0/V1 in primary and liver metastatic PDAC tumours and versican V0/V1 supports fibroblast proliferation.

Clinical significance and potential pathogenesis of VCAN in adult non-cystic fibrosis bronchiectasis: a retrospective study.

BACKGROUND: The pathogenesis of adult non-cystic fibrosis (CF) bronchiectasis is complex, and the relevant molecular mechanism remains ambiguous. Versican (VCAN) is a key factor in inflammation through interactions with adhesion molecules. This study constructs a stable panoramic map of mRNA, reveals the possible pathogenesis of bronchiectasis, and provides new ideas and methods for bronchiectasis. METHODS: Peripheral blood and tissue gene expression data from patients with bronchiectasis and normal control were selected by bioinformatics analysis. The expression of VCAN in peripheral blood and bronchial tissues of bronchiectasis were obtained by transcriptome sequencing. The protein expression levels of VCAN in serums were verified by the enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of VCAN in co-culture of Pseudomonas aeruginosa and bronchial epithelial cells were verified by real-time quantitative polymerase chain reaction (RT-qPCR). In addition, the biological function of VCAN was detected by the transwell assay. RESULTS: The expression of VCAN was upregulated in the bronchiectasis group by sequencing analysis (P < 0.001). The expression of VCAN in the bronchial epithelial cell line BEAS-2B was increased in P. aeruginosa (P.a), which was co-cultured with BEAS-2B cells (P < 0.05). The concentration of VCAN protein in the serum of patients with bronchiectasis was higher than that in the normal control group (P < 0.05). Transwell experiments showed that exogenous VCAN protein induced the migration of neutrophils (P < 0.0001). CONCLUSIONS: Our findings indicate that VCAN may be involved in the development of bronchiectasis by increasing the migration of neutrophils and play an important role in bronchial pathogenesis.

Alterations in the Structure, Composition, and Organization of Galactosaminoglycan-Containing Proteoglycans and Collagen Correspond to the Progressive Stages of Dupuytren's Disease.

Dupuytren's disease (DD) is a prevalent fibroproliferative disorder of the hand, shaped by genetic, epigenetic, and environmental influences. The extracellular matrix (ECM) is a complex assembly of diverse macromolecules. Alterations in the ECM's content, structure and organization can impact both normal physiological functions and pathological conditions. This study explored the content and organization of glycosaminoglycans, proteoglycans, and collagen in the ECM of patients at various stages of DD, assessing their potential as prognostic indicators. This research reveals, for the first time, relevant changes in the complexity of chondroitin/dermatan sulfate structures, specifically an increase of disaccharides containing iduronic acid residues covalently linked to either N-acetylgalactosamine 6-O-sulfated or N-acetylgalactosamine 4-O-sulfated, correlating with the disease's severity. Additionally, we noted an increase in versican expression, a high molecular weight proteoglycan, across stages I to IV, while decorin, a small leucine-rich proteoglycan, significantly diminishes as DD progresses, both confirmed by mRNA analysis and protein detection via confocal microscopy. Coherent anti-Stokes Raman scattering (CARS) microscopy further demonstrated that collagen fibril architecture in DD varies importantly with disease stages. Moreover, the urinary excretion of both hyaluronic and sulfated glycosaminoglycans markedly decreased among DD patients.Our findings indicate that specific proteoglycans with galactosaminoglycan chains and collagen arrangements could serve as biomarkers for DD progression. The reduction in glycosaminoglycan excretion suggests a systemic manifestation of the disease.

[Features of genetic mutations in children with high myopia combined with peripheral retinal degenerations]. / Osobennosti mutatsii v genakh u detei s vysokoi blizorukost'yu, sochetayushcheisya s perifericheskimi vitreokhorioretinal'nymi distrofiyami.

Degenerative changes in the peripheral regions of the ocular fundus allow a closer look at both the role of collagen genes and their mutations in children with high myopia. PURPOSE: The study investigates the features of genetic mutations in children with high myopia combined with peripheral retinal degenerations. MATERIAL AND METHODS: Study group was formed from the database of genetic studies of the Scientific and Clinical Center OOO Oftalmic, which consists of 4362 patients referred for medical genetic counseling and molecular genetic testing from 2016 to 2021. Selection criteria were: male and female patients, aged 5-18 years old, who had the following clinical signs: high myopia (>6.00 D) and the presence of peripheral retinal degenerations (PRD). The study considered both isolated cases of ophthalmic pathology, as well as its syndromic forms. The final selection included 40 children. All patients had consulted with a geneticist. Whole-exome sequencing (WES), next generation sequencing (NGS), and single gene sequencing were conducted by taking 5 mL of peripheral venous blood and extracting deoxyribonucleic acid (DNA). RESULTS: In patients with isolated cases of ophthalmic pathology (peripheral retinal degenerations and high myopia) with a confirmed genetic diagnosis, mutations in the COL2A1 gene were detected in 77.4% of cases, and in the COL11A1 gene - in 22.6% of cases. In Stickler syndrome with a confirmed genetic diagnosis, mutations in the COL2A1 gene were detected in 33.3% of cases. In Marshall syndrome, the mutation in the COL11A1 gene was detected in 11.1% of cases. In children with Ehlers-Danlos, Knobloch type 1, Cohen, Marfan, Wagner syndromes mutations in the genes COL5A1, COL18A1, VPS13B, FBN1, VCAN were detected in 55.6% of cases. In 33.3% of cases of Knobloch type 1, Cohen, Wagner syndromes the mutation is found in both copies of the gene (i.e., in both chromosomes), which leads to the development of peripheral retinal degenerations with high myopia. CONCLUSION: The results of the conducted molecular genetic testing expand our understanding of the mutation spectrum in the genes of children with both isolated cases of ophthalmic pathology, as well as syndromic pathology.

V3: an enigmatic isoform of the proteoglycan versican.

V3 is an isoform of the extracellular matrix (ECM) proteoglycan (PG) versican generated through alternative splicing of the versican gene such that the two major exons coding for sequences in the protein core that support chondroitin sulfate (CS) glycosaminoglycan (GAG) chain attachment are excluded. Thus, versican V3 isoform carries no GAGs. A survey of PubMed reveals only 50 publications specifically on V3 versican, so it is a very understudied member of the versican family, partly because to date there are no antibodies that can distinguish V3 from the CS-carrying isoforms of versican, that is, to facilitate functional and mechanistic studies. However, a number of in vitro and in vivo studies have identified the expression of the V3 transcript during different phases of development and in disease, and selective overexpression of V3 has shown dramatic phenotypic effects in "gain and loss of function" studies in experimental models. Thus, we thought it would be useful and instructive to discuss the discovery, characterization, and the putative biological importance of the enigmatic V3 isoform of versican.

Single-cell transcriptome analysis identifies Versican(+) myofibroblast as a hallmark for thoracic aortic aneurysm marked by activation of PI3K-AKT signaling pathway.

BACKGROUND: Thoracic aortic aneurysm (TAA) is a silent but dangerous cardiovascular disease. Understanding molecular mechanisms of TAA on single-cell level might provide new strategies for preventing and treating TAA. METHODS: Single-cell RNA sequencing was performed on control and aneurysmal thoracic aorta to find out specific cell clusters and cell types. Western blot and histological staining were used to verify the findings of single-cell transcriptome analysis. Characteristics of Versican (VCAN) overexpressed myofibroblast was evaluated through bioinformatic methods and experimental validation. RESULTS: A total of 3 control and 8 TAA specimens were used for single-cell transcriptome analysis including 48,128 thoracic aortic cells. Among these cells, we found out a specific cell cluster containing both hallmarks of smooth muscle cell (SMC) and fibroblast. Thus, we defined these cells as myofibroblast. Further single-cell transcriptome analysis identified VCAN as a cellular marker of myofibroblast. Western blot and histological staining revealed that VCAN(+) myofibroblast was significantly increased in TAA specimens compared with control individuals. Differential analysis, functional, pathway enrichment analysis and cell-cell communication analysis demonstrated that VCAN(+) myofibroblast was closely associated with previous reported TAA associated pathological process including SMC proliferation, SMC migration and extracellular matrix (ECM) disruption. Pathway analysis found out significant activation of PI3K-AKT signaling pathway within VCAN(+) myofibroblast, which was further confirmed by experimental validation. CONCLUSIONS: Single-cell RNA sequencing identified VCAN(+) myofibroblast as a typical cellular hallmark of TAA. These cells might participate in the pathogenesis of TAA through activation of PI3K-AKT signaling pathway to link SMC proliferation, SMC migration and ECM disruption.

TGF-ß1 dominates stromal fibroblast-mediated EMT via the FAP/VCAN axis in bladder cancer cells.

BACKGROUND: Bladder cancer is one of the most common malignant tumors of the urinary system and is associated with a poor prognosis once invasion and distant metastases occur. Epithelial-mesenchymal transition (EMT) drives metastasis and invasion in bladder cancer. Transforming growth factor ß1 (TGF-ß1) and stromal fibroblasts, especially cancer-associated fibroblasts (CAFs), are positive regulators of EMT in bladder cancer. However, it remains unclear how TGF-ß1 mediates crosstalk between bladder cancer cells and CAFs and how it induces stromal fibroblast-mediated EMT in bladder cancer. We aimed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. METHODS: Primary CAFs with high expression of fibroblast activation protein (FAP) were isolated from bladder cancer tissue samples. Subsequently, different conditioned media were used to stimulate the bladder cancer cell line T24 in a co-culture system. Gene set enrichment analysis, a human cytokine antibody array, and cytological assays were performed to investigate the mechanism of TGF-ß1 regulation of stromal fibroblast-mediated EMT in bladder cancer cells. RESULTS: Among the TGF-ß family, TGF-ß1 was the most highly expressed factor in bladder cancer tissue and primary stromal fibroblast supernatant. In the tumor microenvironment, TGF-ß1 was mainly derived from stromal fibroblasts, especially CAFs. In stimulated bladder cells, stromal fibroblast-derived TGF-ß1 promoted bladder cancer cell migration, invasion, and EMT. Furthermore, TGF-ß1 promoted the activation of stromal fibroblasts, inducing CAF-like features, by upregulating FAP in primary normal fibroblasts and a normal fibroblast cell line. Stromal fibroblast-mediated EMT was induced in bladder cancer cells by TGF-ß1/FAP. Versican (VCAN), a downstream molecule of FAP, plays an essential role in TGF-ß1/FAP axis-induced EMT in bladder cancer cells. VCAN may also function through the PI3K/AKT1 signaling pathway. CONCLUSIONS: TGF-ß1 is a critical mediator of crosstalk between stromal fibroblasts and bladder cancer cells. We revealed a new mechanism whereby TGF-ß1 dominated stromal fibroblast-mediated EMT of bladder cancer cells via the FAP/VCAN axis and identified potential biomarkers (FAP, VCAN, N-cadherin, and Vimentin) of bladder cancer. These results enhance our understanding of bladder cancer invasion and metastasis and provide potential strategies for diagnosis, treatment, and prognosis.

Plasma versican and plasma exosomal versican as potential diagnostic markers for non-small cell lung cancer.

BACKGROUND AND AIMS: This study aimed to investigate the expression of plasma versican and plasma exosomal versican in non-small cell lung cancer (NSCLC) and its correlation with clinicopathological features, and to evaluate its diagnostic performance in NSCLC and its predictive function for NSCLC incidence and metastasis risk. MATERIALS AND METHODS: There were 110 instances of NSCLC, 42 cases of benign lung disease, and 55 healthy controls from September 2018 to October 2020 at Tongji Hospital Affiliated to Tongji University. Blood was collected and plasma was separated before surgery, and plasma exosomes were extracted by ExoQuick kit. Morphological and molecular phenotype identification of exosomes was performed by transmission electron microscopy, Nanosight particle tracking analysis, and western blotting. Plasma versican and plasma exosomal versican were detected in all subjects to assess their expression levels and diagnostic value in NSCLC. Clinicopathological data were collected to explore correlations between abnormal plasma versican and plasma exosomal versican expression and clinicopathological parameters. Receiver operating characteristic (ROC) curve was used to judge its diagnostic performance in NSCLC, and binary logistic regression analysis was used to predict the risk of NSCLC incidence and metastasis. RESULTS: Plasma versican and plasma exosomal versican expression in NSCLC patients was significantly upregulated and was significantly higher in T3 + T4 patients compared with T1 + T2 patients (P < 0.05); the levels of plasma versican and plasma exosomal versican were positively correlated with lymph node metastasis, distant metastases (e.g., brain, bone), and mutation(e.g., EGFR,ALK)in NSCLC patients (all P < 0.05). Furthermore, ROC curve analysis showed that plasma versican and plasma exosomal versican had higher AUC values than NSE, CYFRA21-1, and SCC, and better diagnostic performance in NSCLC patients. However, the AUC and diagnostic performances of plasma versican and plasma exosomal versican in advanced-stage NSCLC patients were not shown to be significantly better than CEA. The results of binary logistic regression analysis showed that high levels of plasma exosomal versican had higher predictive value for lung cancer incidence, while high levels of plasma versican had higher predictive value for lung cancer metastasis. CONCLUSION: Our findings showed that plasma versican and plasma exosomal versican might be potential diagnostic markers for NSCLC. High plasma exosomal versican expression can be used as a predictor of NSCLC risk and high plasma versican expression can be used as a predictor of NSCLC metastasis risk.

Versican core protein aids in the diagnosis and grading of breast phyllodes tumor.

Phyllodes tumors (PTs) are biphasic fibroepithelial lesions that occur in the breast. Diagnosing and grading PTs remains a challenge in a small proportion of cases, due to the lack of reliable specific biomarkers. We screened a potential marker versican core protein (VCAN) through microproteomics analysis, validated its role for the grading of PTs by immunohistochemistry, and analyzed the correlation between VCAN expression and clinicopathological characteristics. Cytoplasmic immunoreactivity for VCAN was identified in all benign PT samples, among which 40 (93.0 %) showed VCAN-positive staining in ≥50 % of tumor cells. Eight (21.6 %) borderline PT samples showed VCAN-positive staining in ≥50 % of the cells with weak to moderate staining intensity, whereas 29 samples (78.4 %) showed VCAN-positive staining in <50 % of the cells. In malignant PTs, 16 (84.2 %) and three (15.8 %) samples showed VCAN-positive staining in <5 % and 5-25 % of stromal cells, respectively. Fibroadenomas showed a similar expression pattern to benign PTs. Fisher's exact test showed that the percentages of positive cells (P < .001) and staining intensities (P < .001) of tumor cells were significantly different between the five groups. VCAN positivity was associated with tumor categories (P < .0001) and CD34 expression (P < .0001). The expression of VCAN gradually decreases as the tumor categories increases, following recurrence. To the best of our knowledge, our results are the first in the literature to reveal that VCAN is useful for diagnosing and grading PTs. The expression level of VCAN appeared to be negatively associated with PT categories, suggesting that dysregulation of VCAN may be involved in the tumor progression of PTs.

VCAN Hypomethylation and Expression as Predictive Biomarkers of Drug Sensitivity in Upper Urinary Tract Urothelial Carcinoma.

Versican (VCAN), also known as extracellular matrix proteoglycan 2, has been suggested as a potential biomarker in cancers. Previous research has found that VCAN is highly expressed in bladder cancer. However, its role in predicting outcomes for patients with upper urinary tract urothelial cancer (UTUC) is not well understood. In this study, we collected tissues from 10 patients with UTUC, including 6 with and 4 without lymphovascular invasion (LVI), a pathological feature that plays a significant role in determining metastasis. Results from RNA sequencing revealed that the most differentially expressed genes were involved in extracellular matrix organization. Using the TCGA database for clinical correlation, VCAN was identified as a target for study. A chromosome methylation assay showed that VCAN was hypomethylated in tumors with LVI. In our patient samples, VCAN expression was also found to be high in UTUC tumors with LVI. In vitro analysis showed that knocking down VCAN inhibited cell migration but not proliferation. A heatmap analysis also confirmed a significant correlation between VCAN and migration genes. Additionally, silencing VCAN increased the effectiveness of cisplatin, gemcitabine and epirubicin, thus providing potential opportunities for clinical application.

Adipose Mesenchymal Stromal Cell-Derived Exosomes Carrying MiR-122-5p Antagonize the Inhibitory Effect of Dihydrotestosterone on Hair Follicles by Targeting the TGF-ß1/SMAD3 Signaling Pathway.

Androgenic alopecia (AGA) is the most common type of hair loss, where local high concentrations of dihydrotestosterone (DHT) in the scalp cause progressive shrinkage of the hair follicles, eventually contributing to hair loss. Due to the limitations of existing methods to treat AGA, the use of multi-origin mesenchymal stromal cell-derived exosomes has been proposed. However, the functions and mechanisms of action of exosomes secreted by adipose mesenchymal stromal cells (ADSCs-Exos) in AGA are still unclear. Using Cell Counting Kit-8 (CCK8) analysis, immunofluorescence staining, scratch assays, and Western blotting, it was found that ADSC-Exos contributed to the proliferation, migration, and differentiation of dermal papilla cells (DPCs) and up-regulated the expression of cyclin, ß-catenin, versican, and BMP2. ADSC-Exos also mitigated the inhibitory effects of DHT on DPCs and down-regulated transforming growth factor-beta1 (TGF-ß1) and its downstream genes. Moreover, high-throughput miRNA sequencing and bioinformatics analysis identified 225 genes that were co-expressed in ADSC-Exos; of these, miR-122-5p was highly enriched and was found by luciferase assays to target SMAD3. ADSC-Exos carrying miR-122-5p antagonized DHT inhibition of hair follicles, up-regulated the expression of ß-catenin and versican in vivo and in vitro, restored hair bulb size and dermal thickness, and promoted the normal growth of hair follicles. So, ADSC-Exos enhanced the regeneration of hair follicles in AGA through the action of miR-122-5p and the inhibition of the TGF-ß/SMAD3 axis. These results suggest a novel treatment option for the treatment of AGA.

Targeting Chondroitin Sulphate Synthase 1 (Chsy1) Promotes Axon Growth Following Neurorrhaphy by Suppressing Versican Accumulation.

Versican is a chondroitin sulfate proteoglycan (CSPG), which deposits in perineurium as a physical barrier and prevents the growth of axons out of the fascial boundary. Several studies have indicated that the chondroitin sulfate (CS) chains on versican have several possible functions beyond the physical barrier, including the ability to stabilize versican core protein in the extracellular matrix. As chondroitin sulfate synthase 1 (Chsy1) is a crucial enzyme for CS elongation, we hypothesized that in vivo knockdown of Chsy1 at peripheral nerve lesion site may decrease CS and versican accumulation, and result in accelerating neurite regeneration. In the present study, end-to-side neurorrhaphy (ESN) in Wistar rats was used as an in vivo model of peripheral nerve injury to evaluate nerve regeneration after surgical intervention. The distribution and expression of versican and Chsy1 in regenerating axons after ESN was studied using confocal microscopy and western blotting. Chsy1 was silenced at the nerve lesion (surgical) site using in vivo siRNA transfection. The results indicated that Chsy1 was successfully silenced in nerve tissue, and its downregulation was associated with functional recovery of compound muscle action potential. Silencing of Chsy1 also decreased the accumulation of versican core protein, suggesting that transient treating of Chsy1-siRNA may be an alternative and an effective strategy to promote injured peripheral nerve regeneration.

Defining the versican interactome in lung health and disease.

The extracellular matrix (ECM) imparts critical mechanical and biochemical information to cells in the lungs. Proteoglycans are essential constituents of the ECM and play a crucial role in controlling numerous biological processes, including regulating cellular phenotype and function. Versican, a chondroitin sulfate proteoglycan required for embryonic development, is almost absent from mature, healthy lungs and is reexpressed and accumulates in acute and chronic lung disease. Studies using genetically engineered mice show that the versican-enriched matrix can be pro- or anti-inflammatory depending on the cellular source or disease process studied. The mechanisms whereby versican develops a contextual ECM remain largely unknown. The primary goal of this review is to provide an overview of the interaction of versican with its many binding partners, the "versican interactome," and how through these interactions, versican is an integrator of complex extracellular information. Hopefully, the information provided in this review will be used to develop future studies to determine how versican and its binding partners can develop contextual ECMs that control select biological processes. Although this review focuses on versican and the lungs, what is described can be extended to other proteoglycans, tissues, and organs.

Proteolysis: a key post-translational modification regulating proteoglycans.

Proteoglycans are composite molecules comprising a protein backbone, i.e., the core protein, with covalently attached glycosaminoglycan chains of distinct chemical types. Most proteoglycans are secreted or attached to the cell membrane. Their specialized structures, binding properties, and biophysical attributes underlie diverse biological roles, which include modulation of tissue mechanics, cell adhesion, and the sequestration and regulated release of morphogens, growth factors, and cytokines. As an irreversible post-translational modification, proteolysis has a profound impact on proteoglycan function, abundance, and localization. Proteolysis is required for molecular maturation of some proteoglycans, clearance of extracellular matrix proteoglycans during tissue remodeling, generation of bioactive fragments from proteoglycans, and ectodomain shedding of cell-surface proteoglycans. Genetic evidence shows that proteoglycan core protein proteolysis is essential for diverse morphogenetic events during embryonic development. In contrast, dysregulated proteoglycan proteolysis contributes to osteoarthritis, cardiovascular disorders, cancer, and inflammation. Proteolytic fragments of perlecan, versican, aggrecan, brevican, collagen XVIII, and other proteoglycans are associated with independent biological activities as so-called matrikines. Yet, proteoglycan proteolysis has been investigated to only a limited extent to date. Here, we review the actions of proteases on proteoglycans and illustrate their functional impact with several examples. We discuss the applications and limitations of strategies used to define cleavage sites in proteoglycans and explain how proteoglycanome-wide proteolytic mapping, which is desirable to fully understand the impact of proteolysis on proteoglycans, can be facilitated by integrating classical proteoglycan isolation methods with mass spectrometry-based proteomics.

Aggrecan and versican: two brothers close or apart.

Aggrecan (Acan) and versican (Vcan) are large chondroitin sulfate proteoglycans of the extracellular matrix. They share the same structural domains at both N- and C-termini. The N-terminal G1 domain binds hyaluronan (HA), forms an HA-rich matrix, and regulates HA-mediated signaling. The C-terminal G3 domain binds other extracellular matrix molecules and forms a supramolecular structure that stores transforming growth factor ß (TGFß) and bone morphogenetic proteins (BMPs) and regulates their signaling. EGF-like motifs in the G3 domain may directly act like an EGF ligand. Both Acan and Vcan are present in cartilage, intervertebral disc, brain, heart, and aorta. Their localizations are essentially reciprocal. This review describes their structural domains, expression patterns and functions, and regulation of their expression.

Loss of versican and production of hyaluronan in lung epithelial cells are associated with airway inflammation during RSV infection.

Airway inflammation is a critical feature of lower respiratory tract infections caused by viruses such as respiratory syncytial virus (RSV). A growing body of literature has demonstrated the importance of extracellular matrix changes such as the accumulation of hyaluronan (HA) and versican in the subepithelial space in promoting airway inflammation; however, whether these factors contribute to airway inflammation during RSV infection remains unknown. To test the hypothesis that RSV infection promotes inflammation via altered HA and versican production, we studied an ex vivo human bronchial epithelial cell (BEC)/human lung fibroblast (HLF) coculture model. RSV infection of BEC/HLF cocultures led to decreased hyaluronidase expression by HLFs, increased accumulation of HA, and enhanced adhesion of U937 cells as would be expected with increased HA. HLF production of versican was not altered following RSV infection; however, BEC production of versican was significantly downregulated following RSV infection. In vivo studies with epithelial-specific versican-deficient mice [SPC-Cre(+) Vcan-/-] demonstrated that RSV infection led to increased HA accumulation compared with control mice, which also coincided with decreased hyaluronidase expression in the lung. SPC-Cre(+) Vcan-/- mice demonstrated enhanced recruitment of monocytes and neutrophils in bronchoalveolar lavage fluid and increased neutrophils in the lung compared with SPC-Cre(-) RSV-infected littermates. Taken together, these data demonstrate that altered extracellular matrix accumulation of HA occurs following RSV infection and may contribute to airway inflammation. In addition, loss of epithelial expression of versican promotes airway inflammation during RSV infection further demonstrating that versican's role in inflammatory regulation is complex and dependent on the microenvironment.

TIGIT is the central player in T-cell suppression associated with CAR T-cell relapse in mantle cell lymphoma.

BACKGROUND: Chimeric antigen receptor (CAR) T-cell therapy using brexucabtagene autoleucel (BA) induces remission in many patients with mantle cell lymphoma (MCL), and BA is the only CAR T-cell therapy approved by the FDA for MCL. However, development of relapses to BA is recognized with poor patient outcomes. Multiple CAR T-cell therapies have been approved for other lymphomas and the resistance mechanisms have been investigated. However, the mechanisms underlying BA relapse in MCL have not been investigated and whether any previously reported resistance mechanisms apply to BA-relapsed patients with MCL is unknown. METHODS: To interrogate BA resistance mechanisms in MCL, we performed single-cell RNA sequencing on 39 longitudinally collected samples from 15 BA-treated patients, and multiplex cytokine profiling on 80 serial samples from 20 patients. RESULTS: We demonstrate that after BA relapse, the proportion of T cells, especially cytotoxic T cells (CTLs), decreased among non-tumor cells, while the proportion of myeloid cells correspondingly increased. TIGIT, LAG3, and CD96 were the predominant checkpoint molecules expressed on exhausted T cells and CTLs; only TIGIT was significantly increased after relapse. CTLs expanded during remission, and then contracted during relapse with upregulated TIGIT expression. Tumor cells also acquired TIGIT expression after relapse, leading to the enhanced interaction of tumor cell TIGIT with monocyte CD155/PVR. In myeloid cells, post-relapse HLA-II expression was reduced relative to pretreatment and during remission. Myeloid-derived suppressor cells (MDSCs) were enriched after relapse with elevated expression of activation markers, including CLU (clusterin) and VCAN (versican). Extracellular chemokines (CCL4, CXCL9, CXCL13), soluble checkpoint inhibitors (sPD-L1, sTIM3, s4-1BB), and soluble receptors (sIL-2R, sTNFRII) were decreased during remission but elevated after relapse. CONCLUSIONS: Our data demonstrate that multiple tumor-intrinsic and -extrinsic factors are associated with T-cell suppression and BA relapse. Among these, TIGIT appears to be the central player given its elevated expression after BA relapse in not only CTLs but also MCL cells. The acquisition of TIGIT expression on tumor cells is MCL-specific and has not been reported in other CAR T-treated diseases. Together, our data suggest that co-targeting TIGIT may prevent CAR T relapses and thus promote long-term progression-free survival in MCL patients.