Emerging role of CCN family proteins in fibrosis

The novel thromboxane prostanoid receptor mediates CTGF production to drive human nasal fibroblast self-migration through NF-κB and PKCδ-CREB signaling pathways

Chronic rhinosinusitis without nasal polyp (CRSsNP) is characterized by tissue repair/remodeling and the subepithelial stroma region in whose nasal mucosa has been reported by us to have thromboxane A2 (TXA2) prostanoid (TP) receptor and overexpress connective tissue growth factor (CTGF). Therefore, this study aimed to investigate the relationship between TP receptor activation and CTGF production/function in human CRSsNP nasal mucosa stromal fibroblasts. We found that TP agonists including U46619 and IBOP ([1S-[1α,2α(Z),3β(1E,3 S*),4α]]-7-[3-[3-hydroxy-4-(4-iodophenoxy)-1-butenyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid) could promote CTGF protein/messenger RNA expression and secretion. The pharmacological intervention and TP activation assay with U46619 identified the possible participation of PKCμ, PKCδ, nuclear factor-κB (NF-κB), and cyclic AMP response element-binding protein (CREB) phosphorylation/activation in the CTGF induction. Moreover, a phorbol ester-phorbol-12-myristate 13-acetate (PMA) exhibited a similar cellular signaling and CTGF production profile to that elicited by TP activation. However, further small interfering RNA interference analysis revealed that only NF-κB and PKCδ-CREB pathways were necessarily required for TP-mediated CTGF production, which could not be completely supported by those findings from PMA. Finally, in a functional assay, although CTGF did not affect fibroblast proliferation, TP-mediated CTGF could drive novel self-migration in fibroblasts both in the scratch/wound healing and transwell apparatus assays. Meanwhile, the overall staining for stress fibers and formation of the lamellipodia and filopodia-like structures was concomitantly increased in the treated migrating cells. Collectively, we provided here that novel TP mediates CTGF production and self-migration in human nasal fibroblasts through NF-κB and PKCδ-CREB signaling pathways. More importantly, we also demonstrated that thromboxane, TP receptor, CTGF, and stromal fibroblasts may act in concert in the tissue remodeling/repair process during CRSsNP development and progression.

Effects and Significance of Dicliptera chinensis Polysaccharide on the Expression of Transforming Growth Factor β1/Connective Tissue Growth Factor Pathway in the Masseter and Head and Neck Skin of Rats With Radiation-Induced Fibrosis

PURPOSE

To investigate whether Dicliptera chinensis polysaccharide (DCP) can alleviate radiation-induced fibrosis of masseter and head and neck skin.

METHODS

SD rats were divided into the control, the irradiation (IR), the IR + low dose DCP (200 mg/kg), and the IR + high dose DCP (400 mg/kg) groups. The head and neck of rats in the last 3 groups received a single dose of 18 Gy X-ray. At 1st, 2nd, 4th week (w) after radiation, haematoxylin and eosin staining were performed on masseter and skin to observe the histopathological changes; immunohistochemistry staining was performed to observe the pathological changes of the skin; Masson staining was performed on masseter and skin to observe the collagen deposition; western blot analysis was used on masseter to calculate the relative transforming growth factor β1 (TGF-β1), connective tissue growth factor (CTGF) expressions; ELISA was used to detect the contents of TGF-β1 and CTGF in skin and the contents of type I and type III collagens in masseter and skin.

RESULTS

In terms of skin, compared to the IR group, the IR + high-dose DCP group exhibited relatively smaller changes in skin structure, lower levels of TGF-β1 and CTGF; thinner skin thickness was observed at the 4th w after radiation; and the positive rates of collagen fibre and the optical densities of type I and type III collagens were lower at the 2nd and 4th w. For the masseter, compared to the IR group, the morphological changes were improved and the expression levels of TGF-β1 and CTGF proteins decreased in the 2 DCP dose groups at 2nd and 4th w.

CONCLUSION

DCP can reduce the formation and accumulation of type I and type III collagens after IR and ameliorate radiation-induced fibrosis of masseter and skin by down-regulating the expressions of TGF-β1 and CTGF.

An overview of CCN4 (WISP1) role in human diseases

CCN4 (cellular communication network factor 4), a highly conserved, secreted cysteine-rich matricellular protein is emerging as a key player in the development and progression of numerous disease pathologies, including cancer, fibrosis, metabolic and inflammatory disorders. Over the past two decades, extensive research on CCN4 and its family members uncovered their diverse cellular mechanisms and biological functions, including but not limited to cell proliferation, migration, invasion, angiogenesis, wound healing, repair, and apoptosis. Recent studies have demonstrated that aberrant CCN4 expression and/or associated downstream signaling is key to a vast array of pathophysiological etiology, suggesting that CCN4 could be utilized not only as a non-invasive diagnostic or prognostic marker, but also as a promising therapeutic target. The cognate receptor of CCN4 remains elusive till date, which limits understanding of the mechanistic insights on CCN4 driven disease pathologies. However, as therapeutic agents directed against CCN4 begin to make their way into the clinic, that may start to change. Also, the pathophysiological significance of CCN4 remains underexplored, hence further research is needed to shed more light on its disease and/or tissue specific functions to better understand its clinical translational benefit. This review highlights the compelling evidence of overlapping and/or diverse functional and mechanisms regulated by CCN4, in addition to addressing the challenges, study limitations and knowledge gaps on CCN4 biology and its therapeutic potential.

Zerumbone alleviated bleomycin-induced pulmonary fibrosis in mice via SIRT1/Nrf2 pathway

Pulmonary fibrosis (PF) is a persistent interstitial lung condition for which effective treatment options are currently lacking. Zerumbone (zerum), a humulane sesquiterpenoid extracted from Zingiber zerumbet Smith, has been documented in previous studies to possess various pharmacological benefits. The aim of this study was to observe and investigate the therapeutic effects and mechanisms of zerum on pulmonary fibrosis. We utilized a transforming growth factor (TGF)-β1-induced human lung fibroblast (MRC-5) activation model and a bleomycin-induced pulmonary fibrosis mouse model. Cell counting kit 8 (CCK8) and cell migration assays were performed to assess the effects of zerum on MRC-5 cells. Masson's trichrome, Hematoxylin and Eosin (HE), and Sirius Red staining were conducted for pathological evaluation of lung tissue. Western blot experiments were conducted to measure the protein expression levels of Collagen I, α-SMA, Nrf2, and SIRT1. Immunofluorescence and immunohistochemistry assays were used to detect the expression of reactive oxygen species (ROS), Nrf2, and α-SMA. ELISA was employed to measure the levels of MDA, SOD, and GSH-Px. Our findings from in vitro and in vivo studies demonstrated that zerum significantly inhibited the migration ability of TGF-β1-induced MRC-5 cells, reduced ROS production in TGF-β1-induced MRC-5 cells and pulmonary fibrosis mice, and decreased the expression of Collagen I and α-SMA proteins. Additionally, zerum activated the SIRT1/Nrf2 signaling pathway in TGF-β1-induced MRC-5 cells and pulmonary fibrosis mice. Knockdown of SIRT1 abolished the anti-fibrotic effects of zerum. These results suggest that zerum inhibits TGF-β1 and BLM-induced cell and mouse pulmonary fibrosis by activating the SIRT1/Nrf2 pathway.

Matricellular proteins: Potential biomarkers in head and neck cancer

The extracellular matrix (ECM) is a complex network of diverse multidomain macromolecules, including collagen, proteoglycans, and fibronectin, that significantly contribute to the mechanical properties of tissues. Matricellular proteins (MCPs), as a family of non-structural proteins, play a crucial role in regulating various ECM functions. They exert their biological effects by interacting with matrix proteins, cell surface receptors, cytokines, and proteases. These interactions govern essential cellular processes such as differentiation, proliferation, adhesion, migration as well as multiple signal transduction pathways. Consequently, MCPs are pivotal in maintaining tissue homeostasis while orchestrating intricate molecular mechanisms within the ECM framework. The expression level of MCPs in adult steady-state tissues is significantly low; however, under pathological conditions such as inflammation and cancer, there is a substantial increase in their expression. In recent years, an increasing number of studies have focused on elucidating the role and significance of MCPs in the development and progression of head and neck cancer (HNC). During HNC progression, there is a remarkable upregulation in MCP expression. Through their distinctive structure and function, they actively promote tumor growth, invasion, epithelial-mesenchymal transition, and lymphatic metastasis of HNC cells. Moreover, by binding to integrins and modulating various signaling pathways, they effectively execute their biological functions. Furthermore, MCPs also hold potential as prognostic indicators. Although the star proteins of various MCPs have been extensively investigated, there remains a plethora of MCP family members that necessitate further scrutiny. This article comprehensively examines the functionalities of each MCP and highlights the research advancements in the context of HNC, with an aim to identify novel biomarkers for HNC and propose promising avenues for future investigations.

Connective Tissue Growth Factor: Regulation, Diseases, and Drug Discovery

In drug discovery, selecting targeted molecules is crucial as the target could directly affect drug efficacy and the treatment outcomes. As a member of the CCN family, CTGF (also known as CCN2) is an essential regulator in the progression of various diseases, including fibrosis, cancer, neurological disorders, and eye diseases. Understanding the regulatory mechanisms of CTGF in different diseases may contribute to the discovery of novel drug candidates. Summarizing the CTGF-targeting and -inhibitory drugs is also beneficial for the analysis of the efficacy, applications, and limitations of these drugs in different disease models. Therefore, we reviewed the CTGF structure, the regulatory mechanisms in various diseases, and drug development in order to provide more references for future drug discovery.

Balance between Pro- and Antifibrotic Proteins in Mesenchymal Stromal Cell Secretome Fractions Revealed by Proteome and Cell Subpopulation Analysis

Multipotent mesenchymal stromal cells (MSCs) regulate tissue repair through paracrine activity, with secreted proteins being significant contributors. Human tissue repair commonly results in fibrosis, where fibroblast differentiation into myofibroblasts is a major cellular mechanism. MSCs' paracrine activity can inhibit fibrosis development. We previously demonstrated that the separation of MSC secretome, represented by conditioned medium (CM), into subfractions enriched with extracellular vesicles (EV) or soluble factors (SF) boosts EV and SF antifibrotic effect. This effect is realized through the inhibition of fibroblast-to-myofibroblast differentiation in vitro. To unravel the mechanisms of MSC paracrine effects on fibroblast differentiation, we performed a comparative proteomic analysis of MSC secretome fractions. We found that CM was enriched in NF-κB activators and confirmed via qPCR that CM, but not EV or SF, upregulated NF-κB target genes (COX2, IL6, etc.) in human dermal fibroblasts. Furthermore, we revealed that EV and SF were enriched in TGF-β, Notch, IGF, and Wnt pathway regulators. According to scRNAseq, 11 out of 13 corresponding genes were upregulated in a minor MSC subpopulation disappearing in profibrotic conditions. Thus, protein enrichment of MSC secretome fractions and cellular subpopulation patterns shift the balance in fibroblast-to-myofibroblast differentiation, which should be considered in studies of MSC paracrine effects and the therapeutic use of MSC secretome.

Hippo Signaling Mediates TGFβ-Dependent Transcriptional Inputs in Cardiac Cushion Mesenchymal Cells to Regulate Extracellular Matrix Remodeling

The transforming growth factor beta (TGFβ) and Hippo signaling pathways are evolutionarily conserved pathways that play a critical role in cardiac fibroblasts during embryonic development, tissue repair, and fibrosis. TGFβ signaling and Hippo signaling are also important for cardiac cushion remodeling and septation during embryonic development. Loss of TGFβ2 in mice causes cardiac cushion remodeling defects resulting in congenital heart disease. In this study, we used in vitro molecular and pharmacologic approaches in the cushion mesenchymal cell line (tsA58-AVM) and investigated if the Hippo pathway acts as a mediator of TGFβ2 signaling. Immunofluorescence staining showed that TGFβ2 induced nuclear translocation of activated SMAD3 in the cushion mesenchymal cells. In addition, the results indicate increased nuclear localization of Yes-associated protein 1 (YAP1) following a similar treatment of TGFβ2. In collagen lattice formation assays, the TGFβ2 treatment of cushion cells resulted in an enhanced collagen contraction compared to the untreated cushion cells. Interestingly, verteporfin, a YAP1 inhibitor, significantly blocked the ability of cushion cells to contract collagen gel in the absence or presence of exogenously added TGFβ2. To confirm the molecular mechanisms of the verteporfin-induced inhibition of TGFβ2-dependent extracellular matrix (ECM) reorganization, we performed a gene expression analysis of key mesenchymal genes involved in ECM remodeling in heart development and disease. Our results confirm that verteporfin significantly decreased the expression of α-smooth muscle actin (Acta2), collagen 1a1 (Col1a1), Ccn1 (i.e., Cyr61), and Ccn2 (i.e., Ctgf). Western blot analysis indicated that verteporfin treatment significantly blocked the TGFβ2-induced activation of SMAD2/3 in cushion mesenchymal cells. Collectively, these results indicate that TGFβ2 regulation of cushion mesenchymal cell behavior and ECM remodeling is mediated by YAP1. Thus, the TGFβ2 and Hippo pathway integration represents an important step in understanding the etiology of congenital heart disease.

Emerging role of m6A modification in fibrotic diseases and its potential therapeutic effect

Fibrosis can occur in a variety of organs such as the heart, lung, liver and kidney, and its pathological changes are mainly manifested by an increase in fibrous connective tissue and a decrease in parenchymal cells in organ tissues, and continuous progression can lead to structural damage and organ hypofunction, or even failure, seriously threatening human health and life. N6-methyladenosine (m6A) modification, as one of the most common types of internal modifications of RNA in eukaryotes, exerts a multifunctional role in physiological and pathological processes by regulating the metabolism of RNA. With the in-depth understanding and research of fibrosis, we found that m6A modification plays an important role in fibrosis, and m6A regulators can further participate in the pathophysiological process of fibrosis by regulating the function of specific cells. In our review, we summarized the latest research advances in m6A modification in fibrosis, as well as the specific functions of different m6A regulators. In addition, we focused on the mechanisms and roles of m6A modification in cardiac fibrosis, liver fibrosis, pulmonary fibrosis, renal fibrosis, retinal fibrosis and oral submucosal fibrosis, with the aim of providing new insights and references for finding potential therapeutic targets for fibrosis. Finally, we discussed the prospects and challenges of targeted m6A modification in the treatment of fibrotic diseases.

Module 4-Deficient CCN2/Connective Tissue Growth Factor Attenuates the Progression of Renal Fibrosis via Suppression of Focal Adhesion Kinase Phosphorylation in Tubular Epithelial Cells

CCN2/connective tissue growth factor (CTGF) potentially serves as a therapeutic target for chronic kidney disease. Here we investigated CCN2 module-4, encoded by Ccn2 exon 5, through the generation of Ccn2 exon 5 knockout mice (Ex5-/- mice). To investigate renal fibrosis pathogenesis, Ex5-/- mice were employed to model unilateral ureteral obstruction (UUO), unilateral ischemic-reperfusion injury (UIRI), and 5/6 nephrectomy. Interstitial fibrosis was significantly attenuated in the Ex5-/- mice in the three models. Furthermore, phosphorylated focal adhesion kinase (FAK) levels in tubular epithelial cells were significantly lower in the kidneys of the UUO- and UIRI-Ex5-/- mice than those of the Ex5+/+ mice. Moreover, CCN2 module 4-mediated renal tubule FAK and promoted fibrosis. These findings indicate that CCN2 module-4-FAK pathway components will serve as therapeutic targets for effectively attenuating renal fibrosis.

Blocking CCN2 Reduces Established Palmar Neuromuscular Fibrosis and Improves Function Following Repetitive Overuse Injury

The matricellular protein cell communication factor 2/connective tissue growth factor (CCN2/CTGF) is critical to development of neuromuscular fibrosis. Here, we tested whether anti-CCN2 antibody treatment will reduce established forepaw fibro-degenerative changes and improve function in a rat model of overuse injury. Adult female rats performed a high repetition high force (HRHF) task for 18 weeks. Tissues were collected from one subset after 18 wks (HRHF-Untreated). Two subsets were provided 6 wks of rest with concurrent treatment with anti-CCN2 (HRHF-Rest/anti-CCN2) or IgG (HRHF-Rest/IgG). Results were compared to IgG-treated Controls. Forepaw muscle fibrosis, neural fibrosis and entheseal damage were increased in HRHF-Untreated rats, compared to Controls, and changes were ameliorated in HRHF-Rest/anti-CCN2 rats. Anti-CCN2 treatment also reduced phosphorylated-β-catenin (pro-fibrotic protein) in muscles and distal bone/entheses complex, and increased CCN3 (anti-fibrotic) in the same tissues, compared to HRHF-Untreated rats. Grip strength declines and mechanical sensitivity observed in HRHF-Untreated improved with rest; grip strength improved further in HRHF-Rest/anti-CCN2. Grip strength declines correlated with muscle fibrosis, entheseal damage, extraneural fibrosis, and decreased nerve conduction velocity, while enhanced mechanical sensitivity (a pain-related behavior) correlated with extraneural fibrosis. These studies demonstrate that blocking CCN2 signaling reduces established forepaw neuromuscular fibrosis and entheseal damage, which improves forepaw function, following overuse injury.

CCN2 Activates RIPK3, NLRP3 Inflammasome, and NRF2/Oxidative Pathways Linked to Kidney Inflammation

Inflammation is a key characteristic of both acute and chronic kidney diseases. Preclinical data suggest the involvement of the NLRP3/Inflammasome, receptor-interacting protein kinase-3 (RIPK3), and NRF2/oxidative pathways in the regulation of kidney inflammation. Cellular communication network factor 2 (CCN2, also called CTGF in the past) is an established fibrotic biomarker and a well-known mediator of kidney damage. CCN2 was shown to be involved in kidney damage through the regulation of proinflammatory and profibrotic responses. However, to date, the potential role of the NLRP3/RIPK3/NRF2 pathways in CCN2 actions has not been evaluated. In experimental acute kidney injury induced with folic acid in mice, CCN2 deficiency diminished renal inflammatory cell infiltration (monocytes/macrophages and T lymphocytes) as well as the upregulation of proinflammatory genes and the activation of NLRP3/Inflammasome-related components and specific cytokine products, such as IL-1β. Moreover, the NRF2/oxidative pathway was deregulated. Systemic administration of CCN2 to C57BL/6 mice induced kidney immune cell infiltration and activated the NLRP3 pathway. RIPK3 deficiency diminished the CCN2-induced renal upregulation of proinflammatory mediators and prevented NLRP3 modulation. These data suggest that CCN2 plays a fundamental role in sterile inflammation and acute kidney injury by modulating the RIKP3/NLRP3/NRF2 inflammatory pathways.

The advance of CCN3 in fibrosis

The extracellular matrix (ECM) is comprised of various extracellular macromolecules, including collagen, enzymes, and glycoproteins, which offer structural and biochemical support to neighboring cells. After tissue injury, extracellular matrix proteins deposit in the damaged tissue to promote tissue healing. However, an imbalance between ECM production and degradation can result in excessive deposition, leading to fibrosis and subsequent organ dysfunction. Acting as a regulatory protein within the extracellular matrix, CCN3 plays a crucial role in numerous biological processes, such as cell proliferation, angiogenesis, tumorigenesis, and wound healing. Many studies have demonstrated that CCN3 can reduce the production of ECM in tissues through diverse mechanisms thereby exerting an inhibitory effect on fibrosis. Consequently, CCN3 emerges as a promising therapeutic target for ameliorating fibrosis.

Recent progress on the role of cellular communication network factors (CCN) 3, 4 and 6 in regulating adiposity, liver fibrosis and pancreatic islets

CCN/WISP (cellular communication network factors, or Wnt-inducted secreted proteins) family of proteins consists of six extracellular matrix (ECM)-associated proteins that regulate development, cell adhesion and proliferation, ECM remodeling, inflammation, and tumorigenesis. In the last two decades, metabolic regulation by these matricellular proteins has been studied extensively, several excellent reviews have covered the roles of CCN1, -2 and - 5. In this brief review, we will focus on those lesser-known members and more recent discoveries, together with other recent articles presenting a more complete picture of the current state of knowledge. We have found that CCN2, -4, and - 5 promote pancreatic islet function, while CCN3 plays a unique and negative role. CCN3 and - 4 are pro-adiposity leading to insulin resistance, but CCN5 and - 6 are anti-adiposity. While CCN2 and - 4 promote tissue fibrosis and inflammation, all other four members are clearly anti-fibrotic. As for cellular signaling, they are known to interact with integrins, other cell membrane proteins and ECM thereby regulate Akt/protein kinase B, myocardin-related transcription factor (MRTF), and focal adhesion kinase. Yet, a cohesive mechanism of action to comprehensively explain those major functions is still lacking.

Significance of CCNs in liver regeneration

The liver has an inherent regenerative capacity via hepatocyte proliferation after mild-to-modest damage. When hepatocytes exhaust their replicative ability during chronic or severe liver damage, liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) as an alternative pathway. LPC is often intimately associated with hepatic stellate cells (HSC) activation to promote liver fibrosis. The Cyr61/CTGF/Nov (CCN) protein family consists of six extracellular signaling modulators (CCN1-CCN6) with affinity to a repertoire of receptors, growth factors, and extracellular matrix proteins. Through these interactions, CCN proteins organize microenvironments and modulate cell signalings in a diverse variety of physiopathological processes. In particular, their binding to subtypes of integrin (αvβ5, αvβ3, α6β1, αvβ6, etc.) influences the motility and mobility of macrophages, hepatocytes, HSC, and LPC/OC during liver injury. This paper summarizes the current understanding of the significance of CCN genes in liver regeneration in relation to hepatocyte-driven or LPC/OC-mediated pathways. Publicly available datasets were also searched to compare dynamic levels of CCNs in developing and regenerating livers. These insights not only add to our understanding of the regenerative capability of the liver but also provide potential targets for the pharmacological management of liver repair in the clinical setting. Ccns in liver regeneration Restoring damaged or lost tissues requires robust cell growth and dynamic matrix remodeling. Ccns are matricellular proteins highly capable of influencing cell state and matrix production. Current studies have identified Ccns as active players in liver regeneration. Cell types, modes of action, and mechanisms of Ccn induction may vary depending on liver injuries. Hepatocyte proliferation is a default pathway for liver regeneration following mild-to-modest damages, working in parallel with the transient activation of stromal cells, such as macrophages and hepatic stellate cells (HSC). Liver progenitor cells (LPC), also termed oval cells (OC) in rodents, are activated in the form of ductular reaction (DR) and are associated with sustained fibrosis when hepatocytes lose their proliferative ability in severe or chronic liver damage. Ccns may facilitate both hepatocyte regeneration and LPC/OC repair via various mediators (growth factors, matrix proteins, integrins, etc.) for cell-specific and context-dependent functions.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

Metabolic Effects of CCN5/WISP2 Gene Deficiency and Transgenic Overexpression in Mice

CCN5/WISP2 is a matricellular protein, the expression of which is under the regulation of Wnt signaling and IGF-1. Our initial characterization supports the notion that CCN5 might promote the proliferation and survival of pancreatic β-cells and thus improve the metabolic profile of the animals. More recently, the roles of endogenous expression of CCN5 and its ectopic, transgenic overexpression on metabolic regulation have been revealed through two reports. Here, we attempt to compare the experimental findings from those studies, side-by-side, in order to further establish its roles in metabolic regulation. Prominent among the discoveries was that a systemic deficiency of CCN5 gene expression caused adipocyte hypertrophy, increased adipogenesis, and lipid accumulation, resulting in insulin resistance and glucose intolerance, which were further exacerbated upon high-fat diet feeding. On the other hand, the adipocyte-specific and systemic overexpression of CCN5 caused an increase in lean body mass, improved insulin sensitivity, hyperplasia of cardiomyocytes, and increased heart mass, but decreased fasting glucose levels. CCN5 is clearly a regulator of adipocyte proliferation and maturation, affecting lean/fat mass ratio and insulin sensitivity. Not all results from these models are consistent; moreover, several important aspects of CCN5 physiology are yet to be explored.

NOV/CCN3 Promotes Cell Migration and Invasion in Intrahepatic Cholangiocarcinoma via miR-92a-3p

Intrahepatic cholangiocarcinoma (ICC) is a common type of human cancer with a poor prognosis, and investigating the potential molecular mechanisms that can contribute to gene diagnosis and therapy. Herein, based on the recently concerned vertebrate-specific Cyr61/CTGF/NOV (CCN) gene family because of its important roles in diverse diseases, we obtained NOV/CCN3 to query for its potential roles in tumorigenesis via bioinformatics analysis. Experimental validations confirmed that both NOV mRNA and protein are up-regulated in two ICC cell lines, suggesting that it may promote cell migration and invasion by promoting EMT. To elucidate the detailed regulatory mechanism, miR-92a-3p is screened and identified as a negative regulatory small RNA targeting NOV, and further experimental validation demonstrates that miR-92a-3p contributes to NOV-mediated migration and invasion of ICC via the Notch signaling pathway. Our study reveals that NOV may be a potential target for diagnosing and treating ICC, which will provide experimental data and molecular theoretical foundation for cancer treatment, particularly for future precision medicine.

WISP-1 induced by mechanical stress contributes to fibrosis and hypertrophy of the ligamentum flavum through Hedgehog-Gli1 signaling

Ongoing chronic fibrosis and hypertrophy of the ligamentum flavum (LF) is an important cause of lumbar spinal canal stenosis (LSCS). Our previous work showed that WNT1-inducible signaling pathway protein 1 (WISP-1) is a critical driver of LF fibrosis. However, the potential mechanism has not been explored. Here, we found that Gli1 was upregulated in hypertrophic LF tissues and required for fibrogenesis in fibroblasts. Moreover, mechanical stretching increased the expression of WISP-1 in LF fibroblasts. Furthermore, WISP-1 induced fibrogenesis in vitro through the Hedgehog-Gli1 pathway. This conclusion was supported by the fact that WISP-1 activated the Hedgehog-Gli1 pathway in LF fibroblasts and that cyclopamine attenuated the effect of WISP-1-induced fibrogenesis. WISP-1 also promoted the transition of fibroblasts into myofibroblasts via the Hedgehog pathway. Importantly, a hypertrophic LF rabbit model induced by mechanical stress also showed pathological changes in fibrosis and elevated expression of WISP-1, Gli1, and α-SMA. Therapeutic administration of cyclopamine reduced collagen expression, fibroblast proliferation, and myofibroblast differentiation and ameliorated fibrosis in the mechanical stress-induced rabbit model. Collectively, our findings show mechanical stress/WISP-1/Hedgehog signaling as a new fibrotic axis contributing to LF hypertrophy and identify Hedgehog signaling as a therapeutic target for the prevention and treatment of LF fibrosis.

Role of Matricellular CCN Proteins in Skeletal Muscle: Focus on CCN2/CTGF and Its Regulation by Vasoactive Peptides

The Cellular Communication Network (CCN) family of matricellular proteins comprises six proteins that share conserved structural features and play numerous biological roles. These proteins can interact with several receptors or soluble proteins, regulating cell signaling pathways in various tissues under physiological and pathological conditions. In the skeletal muscle of mammals, most of the six CCN family members are expressed during embryonic development or in adulthood. Their roles during the adult stage are related to the regulation of muscle mass and regeneration, maintaining vascularization, and the modulation of skeletal muscle fibrosis. This work reviews the CCNs proteins' role in skeletal muscle physiology and disease, focusing on skeletal muscle fibrosis and its regulation by Connective Tissue Growth factor (CCN2/CTGF). Furthermore, we review evidence on the modulation of fibrosis and CCN2/CTGF by the renin-angiotensin system and the kallikrein-kinin system of vasoactive peptides.

Targeting CCN Proteins in Rheumatoid Arthritis and Osteoarthritis

The CCN family of matricellular proteins (CYR61/CCN1, CTGF/CCN2, NOV/CCN3 and WISP1-2-3/CCN4-5-6) are essential players in the key pathophysiological processes of angiogenesis, wound healing and inflammation. These proteins are well recognized for their important roles in many cellular processes, including cell proliferation, adhesion, migration and differentiation, as well as the regulation of extracellular matrix differentiation. Substantial evidence implicates four of the proteins (CCN1, CCN2, CCN3 and CCN4) in the inflammatory pathologies of rheumatoid arthritis (RA) and osteoarthritis (OA). A smaller evidence base supports the involvement of CCN5 and CCN6 in the development of these diseases. This review focuses on evidence providing insights into the involvement of the CCN family in RA and OA, as well as the potential of the CCN proteins as therapeutic targets in these diseases.