scholarly journals Wnt/β-catenin signaling contributes to articular cartilage homeostasis through lubricin induction in the superficial zone

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Fengjun Xuan ◽  
Fumiko Yano ◽  
Daisuke Mori ◽  
Ryota Chijimatsu ◽  
Yuji Maenohara ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Mechanical Loading ◽  
Cartilage Degeneration ◽  
Mrna Levels ◽  
Superficial Zone ◽  
Gain Of Function ◽  
Wnt Ligands ◽  
Signaling Activation ◽  
Signaling Activity

Abstract Background Both loss- and gain-of-function of Wnt/β-catenin signaling in chondrocytes result in exacerbation of osteoarthritis (OA). Here, we examined the activity and roles of Wnt/β-catenin signaling in the superficial zone (SFZ) of articular cartilage. Methods Wnt/β-catenin signaling activity was analyzed using TOPGAL mice. We generated Prg4-CreERT2;Ctnnb1fl/fl and Prg4-CreERT2;Ctnnb1-ex3fl/wt mice for loss- and gain-of-function, respectively, of Wnt/β-catenin signaling in the SFZ. Regulation of Prg4 expression by Wnt/β-catenin signaling was examined in vitro, as were upstream and downstream factors of Wnt/β-catenin signaling in SFZ cells. Results Wnt/β-catenin signaling activity, as determined by the TOPGAL reporter, was high specifically in the SFZ of mouse adult articular cartilage, where Prg4 is abundantly expressed. In SFZ-specific β-catenin-knockout mice, OA development was significantly accelerated, which was accompanied by decreased Prg4 expression and SFZ destruction. In contrast, Prg4 expression was enhanced and cartilage degeneration was suppressed in SFZ-specific β-catenin-stabilized mice. In primary SFZ cells, Prg4 expression was downregulated by β-catenin knockout, while it was upregulated by β-catenin stabilization by exon 3 deletion or treatment with CHIR99021. Among Wnt ligands, Wnt5a, Wnt5b, and Wnt9a were highly expressed in SFZ cells, and recombinant human WNT5A and WNT5B stimulated Prg4 expression. Mechanical loading upregulated expression of these ligands and further promoted Prg4 transcription. Moreover, mechanical loading and Wnt/β-catenin signaling activation increased mRNA levels of Creb1, a potent transcription factor for Prg4. Conclusions We demonstrated that Wnt/β-catenin signaling regulates Prg4 expression in the SFZ of mouse adult articular cartilage, which plays essential roles in the homeostasis of articular cartilage.

MUSCLE-INDUCED PATELLOFEMORAL JOINT LOADING RAPIDLY AFFECTS CARTILAGE mRNA LEVELS IN A SITE SPECIFIC MANNER

2004 ◽  
Vol 08 (01) ◽  
pp. 1-12 ◽  
Author(s):  
Andrea L. Clark ◽  
Linda Mills ◽  
David A Hart ◽  
Walter Herzog
Keyword(s):  
Articular Cartilage ◽  
Mechanical Loading ◽  
Patellofemoral Joint ◽  
Mrna Level ◽  
Recovery Period ◽  
Cartilage Explants ◽  
Mrna Levels ◽  
Biological Responses

Mechanical loading of articular cartilage affects the synthesis and degradation of matrix macromolecules. Much of the work in this area has involved mechanical loading of articular cartilage explants or cells in vitro and assessing biological responses at the mRNA and protein levels. In this study, we developed a new experimental technique to load an intact patellofemoral joint in vivo using muscle stimulation. The articular cartilages were cyclically loaded for one hour in a repeatable and measurable manner. Cartilage was harvested from central and peripheral regions of the femoral groove and patella, either immediately after loading or after a three hour recovery period. Total RNA was isolated from the articular cartilage and biological responses were assessed on the mRNA level using the reverse transcriptase-polymerase chain reaction. Articular cartilage from intact patellofemoral joints demonstrated heterogeneity at the mRNA level for six of the genes assessed independent of the loading protocol. Cyclical loading of cartilage in its native environment led to alterations in mRNA levels for a subset of molecules when assessed immediately after the loading period. However, the increases in TIMP-1 and decreases in bFGF mRNA levels were transient; being present immediately after load application but not after a three hour recovery period.

Phenotypic maintenance of articular chondrocytes in vitro requires BMP activity

2007 ◽  
Vol 20 (03) ◽  
pp. 185-191 ◽  
Author(s):  
A. O. Oshin ◽  
E. Caporali ◽  
C. R. Byron ◽  
A. A. Stewart ◽  
M. C. Stewart
Keyword(s):  
Articular Cartilage ◽  
Collagen Type ◽  
Articular Chondrocytes ◽  
Soluble Form ◽  
Mrna Levels ◽  
Type Ii ◽  
Collagen Type Ii ◽  
Endogenous Expression ◽  
Chondrocytic Phenotype

SummaryArticular chondrocytes are phenotypically unique cells that are responsible for the maintenance of articular cartilage. The articular chondrocytic phenotype is influenced by a range of soluble factors. In particular, members of the bone morphogenetic protein (BMP) family support the articular chondrocytic phenotype and stimulate synthesis of cartilaginous matrix. This study was carried out to determine the importance of BMPs in supporting the differentiated phenotype of articular chondrocytes in vitro. Exogenous BMP-2 supported expression of collagen type II and aggrecan in monolayer chondrocyte cultures, slowing the dedifferentiation process that occurs under these conditions. In contrast, BMP-2 had little effect on expression of these genes in three-dimensional aggregate cultures. Endogenous BMP-2 expression was lost in monolayer cultures, coincident with the down-regulation of collagen type II and aggrecan mRNAs, whereas BMP-2 mRNA levels were stable in aggregate cultures. Antagonism of endogenous BMP activity in aggregate cultures by Noggin or a soluble form of the BMP receptor resulted in reduced expression of collagen type II and aggrecan mRNAs, reduced collagen type II protein and sulfated glycosaminoglycan (GAG) deposition into the aggregate matrices and reduced secretion of GAGs into the culture media. These results indicate that endogenous BMPs are required for maintenance of the differentiated articular chondrocytic phenotype in vitro. These findings are of importance to cell-based strategies designed to repair articular cartilage. Articular chondrocytes require conditions that will support endogenous expression of BMPs to maintain the specialized phenotype of these cells.

scholarly journals Ginsenoside Rg1 Suppresses Type 2 PRRSV Infection via NF-κB Signaling Pathway In Vitro, and Provides Partial Protection against HP-PRRSV in Piglet

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1045 ◽  
Author(s):  
Yu ◽  
Yi ◽  
Ma ◽  
Wei ◽  
Cai ◽  
...  
Keyword(s):  
Respiratory Syndrome Virus ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Ginsenoside Rg1 ◽  
Virus Attachment ◽  
Current Vaccine ◽  
Anti Oxidant ◽  
Signaling Activation

Porcine reproductive and respiratory syndrome virus (PRRSV) is a huge threat to the modern pig industry, and current vaccine prevention strategies could not provide full protection against it. Therefore, exploring new anti-PRRSV strategies is urgently needed. Ginsenoside Rg1, derived from ginseng and notoginseng, is shown to exert anti-inflammatory, neuronal apoptosis-suppressing and anti-oxidant effects. Here we demonstrate Rg1-inhibited PRRSV infection both in Marc-145 cells and porcine alveolar macrophages (PAMs) in a dose-dependent manner. Rg1 treatment affected multiple steps of the PRRSV lifecycle, including virus attachment, replication and release at concentrations of 10 or 50 µM. Meanwhile, Rg1 exhibited broad inhibitory activities against Type 2 PRRSV, including highly pathogenic PRRSV (HP-PRRSV) XH-GD and JXA1, NADC-30-like strain HNLY and classical strain VR2332. Mechanistically, Rg1 reduced mRNA levels of the pro-inflammatory cytokines, including IL-1β, IL-8, IL-6 and TNF-α, and decreased NF-κB signaling activation triggered by PRRSV infection. Furthermore, 4-week old piglets intramuscularly treated with Rg1 after being challenged with the HP-PRRSV JXA1 strain display moderate lung injury, decreased viral load in serum and tissues, and an improved survival rate. Collectively, our study provides research basis and supportive clinical data for using Ginsenoside Rg1 in PRRSV therapies in swine.

scholarly journals EGFR signaling is critical for maintaining the superficial layer of articular cartilage and preventing osteoarthritis initiation

2016 ◽  
Vol 113 (50) ◽  
pp. 14360-14365 ◽  
Author(s):  
Haoruo Jia ◽  
Xiaoyuan Ma ◽  
Wei Tong ◽  
Basak Doyran ◽  
Zeyang Sun ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
High Surface ◽  
Cartilage Degeneration ◽  
Superficial Layer ◽  
Joint Disease ◽  
Egfr Signaling ◽  
Superficial Zone ◽  
Cartilage Surface ◽  
Healthy Cartilage ◽  
Important Regulator

Osteoarthritis (OA) is the most common joint disease, characterized by progressive destruction of the articular cartilage. The surface of joint cartilage is the first defensive and affected site of OA, but our knowledge of genesis and homeostasis of this superficial zone is scarce. EGFR signaling is important for tissue homeostasis. Immunostaining revealed that its activity is mostly dominant in the superficial layer of healthy cartilage but greatly diminished when OA initiates. To evaluate the role of EGFR signaling in the articular cartilage, we studied a cartilage-specific Egfr-deficient (CKO) mouse model (Col2-Cre EgfrWa5/flox). These mice developed early cartilage degeneration at 6 mo of age. By 2 mo of age, although their gross cartilage morphology appears normal, CKO mice had a drastically reduced number of superficial chondrocytes and decreased lubricant secretion at the surface. Using superficial chondrocyte and cartilage explant cultures, we demonstrated that EGFR signaling is critical for maintaining the number and properties of superficial chondrocytes, promoting chondrogenic proteoglycan 4 (Prg4) expression, and stimulating the lubrication function of the cartilage surface. In addition, EGFR deficiency greatly disorganized collagen fibrils in articular cartilage and strikingly reduced cartilage surface modulus. After surgical induction of OA at 3 mo of age, CKO mice quickly developed the most severe OA phenotype, including a complete loss of cartilage, extremely high surface modulus, subchondral bone plate thickening, and elevated joint pain. Taken together, our studies establish EGFR signaling as an important regulator of the superficial layer during articular cartilage development and OA initiation.

Mechanical Loading Reduces Chondrocyte Death After Single Impact Trauma: Porcine Knee Model

2012 ◽  
Author(s):  
Lauren L. Vernon ◽  
David G. Wilensky ◽  
Chong Wang ◽  
Lee D. Kaplan ◽  
Chun-Yuh C. Huang
Keyword(s):  
Articular Cartilage ◽  
Mechanical Loading ◽  
Motor Vehicle ◽  
Degenerative Changes ◽  
Matrix Composition ◽  
Single Impact ◽  
Knee Model ◽  
Chondrocyte Death ◽  
Porcine Knee

Osteoarthritis often results from degenerative changes induced by trauma such as joint impact injuries sustained during athletics, combat, or motor vehicle accidents. Articular cartilage, avascular in nature, relies of synovial nutrition [1] and lacks sufficient regenerative capabilities [2]. Acute cartilage injuries have been shown to induce cell death [3, 4, 5], leading to reduced chondrocyte density and degenerative changes to the cartilage matrix composition; over time the tissue becomes compromised and loses its ability to maintain and restore itself. It has been demonstrated, that mechanical loading can affect local perfusion and diffusion through the matrix thereby altering the flow of nutrients and metabolites [2, 6]. Furthermore, mechanical loading modulates the chondrocyte biosynthesis of extracellular matrix that is required in the cartilage repair process. In this study, a two part in-vitro porcine knee model was utilized to investigate articular cartilage response immediately following a single impact injury under cyclic mechanical loading conditions.

Mechanical Chondrocyte Damage Thresholds

2012 ◽  
Author(s):  
Mark C. van Turnhout ◽  
Stefan A. H. de Vries ◽  
Corrinus C. van Donkelaar ◽  
Cees W. J. Oomens
Keyword(s):  
Cell Death ◽  
Articular Cartilage ◽  
Mechanical Loading ◽  
Early Stage ◽  
Cartilage Degeneration ◽  
Chondrocyte Apoptosis ◽  
Tissue Volume ◽  
Mechanical Thresholds

Chondrocyte content in articular cartilage is very low. Only 2% to 5% of the tissue volume consists of chondrocytes [1]. Yet, these cells are responsible for maintenance of the tissue. Hence, the loss of chondrocytes that is often occurring at an early stage of cartilage degeneration is detrimental to articular cartilage. Excessive mechanical loading is known to be a cause of cell death. However, mechanical thresholds beyond which chondrocyte apoptosis would be induced are unknown.

scholarly journals Determination of the Depth- and Time- Dependent Mechanical Behavior of Mouse Articular Cartilage Using Cyclic Reference Point Indentation

Cartilage ◽  
2018 ◽  
Vol 11 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Andrew Chang ◽  
Simon Y. Tang
Keyword(s):  
Articular Cartilage ◽  
Mechanical Behavior ◽  
Mouse Models ◽  
Reference Point ◽  
Molecular Mechanisms ◽  
Cartilage Degeneration ◽  
Small Scale ◽  
Superficial Zone ◽  
Vast Number ◽  
Reference Point Indentation

Mouse models of osteoarthritis and cartilage degeneration are important and powerful tools for investigating the molecular mechanisms of the disease pathology. Because of the vast number of genetically modified mouse models that are available for research, the ability to use these models is particularly attractive for the mechanobiologic interactions in the pathogenesis of osteoarthritis. However, the very small scale of mouse articular cartilage, where the healthy tissue is only 80 µm in thickness, poses challenges in quantifying mechanical characteristics of the tissue. We introduce here a novel approach that combines experimental and analytical methods to quantify the nuanced mechanical changes during cartilage degeneration at this scale. Cyclic reference point indentation is used to directly test the murine articular cartilage to obtain the force-deformation and the phase-shift characteristics of the tissue. The cartilage zonal thicknesses are confirmed from histology. These data are then fitted to a parallel spring model to determine the depth-dependent tissue stiffness and modulus. Using this approach, we investigated the effects of trypsin degradation on the zonal mechanical behavior of mouse articular cartilage. We observe a decline of the superficial zone stiffness coupled with the loss of the superficial layer. Subsequent degradation by trypsin allowed the identification of middle- and deep- zone properties. Taken together, this approach can be a useful tool for understanding the disease mechanisms of cartilage homeostasis and degeneration, and for monitoring of therapies for osteoarthritis.

scholarly journals Current Advances in the Regeneration of Degenerated Articular Cartilage: A Literature Review on Tissue Engineering and Its Recent Clinical Translation

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 31
Author(s):  
Farah Daou ◽  
Andrea Cochis ◽  
Massimiliano Leigheb ◽  
Lia Rimondini
Keyword(s):  
Tissue Engineering ◽  
Articular Cartilage ◽  
Literature Review ◽  
Healthy Aging ◽  
Ex Vivo ◽  
Cartilage Degeneration ◽  
Clinical Translation ◽  
Predisposing Factor

Functional ability is the basis of healthy aging. Articular cartilage degeneration is amongst the most prevalent degenerative conditions that cause adverse impacts on the quality of life; moreover, it represents a key predisposing factor to osteoarthritis (OA). Both the poor capacity of articular cartilage for self-repair and the unsatisfactory outcomes of available clinical interventions make innovative tissue engineering a promising therapeutic strategy for articular cartilage repair. Significant progress was made in this field; however, a marked heterogeneity in the applied biomaterials, biofabrication, and assessments is nowadays evident by the huge number of research studies published to date. Accordingly, this literature review assimilates the most recent advances in cell-based and cell-free tissue engineering of articular cartilage and also focuses on the assessments performed via various in vitro studies, ex vivo models, preclinical in vivo animal models, and clinical studies in order to provide a broad overview of the latest findings and clinical translation in the context of degenerated articular cartilage and OA.

scholarly journals Resistance to MET/VEGFR2 Inhibition by Cabozantinib Is Mediated by YAP/TBX5-Dependent Induction of FGFR1 in Castration-Resistant Prostate Cancer

Cancers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 244 ◽  
Author(s):  
Filippos Koinis ◽  
Paul Corn ◽  
Nila Parikh ◽  
Jian Song ◽  
Ioulia Vardaki ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Transcriptional Activation ◽  
Acquired Resistance ◽  
Mrna Levels ◽  
Castration Resistant Prostate Cancer ◽  
Downstream Target ◽  
Disease States ◽  
Signaling Activation

The overall goal of this study was to elucidate the role of FGFR1 induction in acquired resistance to MET and VEGFR2 inhibition by cabozantinib in prostate cancer (PCa) and leverage this understanding to improve therapy outcomes. The response to cabozantinib was examined in mice bearing patient-derived xenografts in which FGFR1 was overexpressed. Using a variety of cell models that reflect different PCa disease states, the mechanism underpinning FGFR1 signaling activation by cabozantinib was investigated. We performed parallel investigations in specimens from cabozantinib-treated patients to confirm our in vitro and in vivo data. FGFR1 overexpression was sufficient to confer resistance to cabozantinib. Our results demonstrate transcriptional activation of FGF/FGFR1 expression in cabozantinib-resistant models. Further analysis of molecular pathways identified a YAP/TBX5-driven mechanism of FGFR1 and FGF overexpression induced by MET inhibition. Importantly, knockdown of YAP and TBX5 led to decreased FGFR1 protein expression and decreased mRNA levels of FGFR1, FGF1, and FGF2. This association was confirmed in a cohort of hormone-naïve patients with PCa receiving androgen deprivation therapy and cabozantinib, further validating our findings. These findings reveal that the molecular basis of resistance to MET inhibition in PCa is FGFR1 activation through a YAP/TBX5-dependent mechanism. YAP and its downstream target TBX5 represent a crucial mediator in acquired resistance to MET inhibitors. Thus, our studies provide insight into the mechanism of acquired resistance and will guide future development of clinical trials with MET inhibitors.

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