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1.
J Transl Med ; 22(1): 467, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755685

RESUMO

BACKGROUND: Osteoarthritis (OA) is a chronic degenerative joint disease causing limited mobility and pain, with no curative treatment available. Recent in vivo studies suggested autonomic alterations during OA progression in patients, yet clinical evidence is scarce. Therefore, autonomic tone was analyzed in OA patients via heart rate variability (HRV) measurements. METHODS: Time-domain (SDRR, RMSSD, pRR50) and frequency-domain (LF, HF, LF/HF) HRV indices were determined to quantify sympathetic and parasympathetic activities. In addition, perceived stress, WOMAC pain as well as serum catecholamines, cortisol and dehydroepiandrosterone-sulphate (DHEA-S) were analyzed. The impact of the grade of disease (GoD) was evaluated by linear regression analysis and correlations with clinical data were performed. RESULTS: GoD significantly impacted the autonomic tone in OA patients. All time-domain parameters reflected slightly decreased HRV in early OA patients and significantly reduced HRV in late OA patients. Moreover, frequency-domain analysis revealed decreased HF and LF power in all OA patients, reflecting diminished parasympathetic and sympathetic activities. However, LF/HF ratio was significantly higher in early OA patients compared to late OA patients and implied a clear sympathetic dominance. Furthermore, OA patients perceived significantly higher chronic stress and WOMAC pain levels compared to healthy controls. Serum cortisol and cortisol/DHEA-S ratio significantly increased with GoD and positively correlated with WOMAC pain. In contrast, serum catecholamines only trended to increase with GoD and pain level. CONCLUSIONS: This prospective study provides compelling evidence of an autonomic dysfunction with indirect sympathetic dominance in early and late knee OA patients for the first time based on HRV analyses and further confirmed by serum stress hormone measurements. Increased sympathetic activity and chronic low-grade inflammation in OA as well as in its major comorbidities reinforce each other and might therefore create a vicious cycle. The observed autonomic alterations coupled with increased stress and pain levels highlight the potential of HRV as a prognostic marker. In addition, modulation of autonomic activity represents an attractive future therapeutic option.


Assuntos
Frequência Cardíaca , Osteoartrite , Sistema Nervoso Simpático , Humanos , Masculino , Feminino , Osteoartrite/fisiopatologia , Osteoartrite/sangue , Osteoartrite/complicações , Pessoa de Meia-Idade , Idoso , Sistema Nervoso Simpático/fisiopatologia , Hidrocortisona/sangue , Dor/fisiopatologia , Dor/sangue
2.
Artigo em Inglês | MEDLINE | ID: mdl-39461410

RESUMO

Osteoarthritis (OA) is a fast-growing and extremely wide research field, in which a substantial increase in knowledge has been achieved over the last year. It covers many different topics; however, a PubMed search using the terms 'osteoarthritis' and 'biology' resulted in only a limited number of studies that were published between April 2023 and April 2024. In order to identify OA-relevant studies that focus on mechanistic studies of biological processes at the tissue, cellular, and molecular level, the following keywords were included as search terms: tissue interactions, single cell sequencing, transcriptomics, extracellular matrix, signaling, ion channels, and pain. The final selection of publications presented in this 'year in review' was influenced by the personal preferences of the authors, and eventually three larger key themes emerged: 1) Joint tissue interactions covering meniscus, subchondral bone, fat tissue, synovium, and synovial fluid. 2) Degeneration of the cartilage extracellular matrix (ECM) and generation of bioactive fragments. 3) Receptors, ion channels, signaling pathways, and cellular metabolism. Many of the studies summarized here identified novel potential targets for OA treatment, and promising results were already obtained addressing these targets in different animal models. It will be exciting to see which findings can be translated into future clinical studies and eventually lead to novel treatment approaches for human OA.

3.
Osteoarthritis Cartilage ; 32(2): 177-186, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37989468

RESUMO

OBJECTIVE: To investigate the effects of 21 days of bed rest immobilization (with and without exercise and nutrition interventions) on type II collagen biomarker concentrations in healthy individuals. DESIGN: Twelve healthy male participants (age 34.2 ± 8.3 years; body mass index 22.4 ± 1.7 kg/m²) were exposed to 6 days ambulatory baseline data collection (BDC), 21 days head-down-tilt bed rest (HDT, CON) + interventions (HDT + resistive vibration exercise (2 times/week, 25 minutes): RVE; HDT + RVE + whey protein (0.6 g/kg body weight/day) and bicarbonate supplementation (90 mmol KHCO3/day: NeX), and 6 days of re-ambulation (R) in a cross-over designed study. The starting HDT condition was randomized (CON-RVE-NEX, RVE-NEX-CON, NEX-CON-RVE). Blood and urine samples were collected before, during, and after HDT. Serum concentrations (s) of CPII, C2C, C1,2C, and urinary concentrations (u) of CTX-II and Coll2-1NO2 were measured. RESULTS: Twenty-one days of HDT resulted in increased sCPII (p < 0.001), sC2C (p < 0.001), and sC1,2C (p = 0.001) (highest increases: sCPII (+24.2% - HDT5), sC2C (+24.4% - HDT7), sC1,2C (+13.5% - HDT2). sC2C remained elevated at R+1 (p = 0.002) and R+6 (p < 0.001) compared to baseline. NeX led to lower sCPII (p < 0.001) and sC1,2C (p = 0.003) compared to CON. uCTX-II (second void and 24-hour urine) increased during HDT (p < 0.001, highest increase on HDT21: second void +82.8% (p < 0.001); 24-hour urine + 77.8% (p < 0.001). NeX resulted in lower uCTX-II concentrations in 24-hour urine (p = 0.012) compared to CON. CONCLUSIONS: Twenty-one days of bed rest immobilization results in type II collagen degradation that does not recover within 6 days of resuming ambulation. The combination of resistive vibration exercise and protein/bicarbonate supplementation minimally counteracted this effect.


Assuntos
Repouso em Cama , Bicarbonatos , Humanos , Masculino , Adulto , Colágeno Tipo II , Repouso em Cama/métodos , Terapia por Exercício/métodos , Decúbito Inclinado com Rebaixamento da Cabeça
4.
Am J Physiol Cell Physiol ; 324(2): C377-C394, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36571440

RESUMO

Osteoarthritis (OA) is among the most frequent diseases of the musculoskeletal system. Degradation of cartilage extracellular matrix (ECM) is a hallmark of OA. During the degradation process, intact/full-length proteins and proteolytic fragments are released which then might induce different downstream responses via diverse receptors, therefore leading to different biological consequences. Collagen type II and the proteoglycan aggrecan are the most abundant components of the cartilage ECM. However, over the last decades, a large number of minor components have been identified and for some of those, a role in the manifold processes associated with OA has already been demonstrated. To date, there is still no therapy able to halt or cure OA. A better understanding of the matrikine landscape occurring with or even preceding obvious degenerative changes in joint tissues is needed and might help to identify molecules that could serve as biomarkers, druggable targets, or even be blueprints for disease modifying drug OA drugs. For this narrative review, we screened PubMed for relevant literature in the English language and summarized the current knowledge regarding the function of selected ECM molecules and the derived matrikines in the context of cartilage and OA.


Assuntos
Cartilagem Articular , Osteoartrite , Humanos , Cartilagem Articular/metabolismo , Osteoartrite/metabolismo , Matriz Extracelular/metabolismo , Agrecanas/metabolismo , Agrecanas/uso terapêutico , Proteínas da Matriz Extracelular/metabolismo , Condrócitos/metabolismo
5.
Am J Physiol Cell Physiol ; 325(2): C365-C384, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37335027

RESUMO

Osteoarthritis (OA) is the most prevalent degenerative joint disease. Besides loss of articular cartilage and synovial inflammation, OA progression is characterized by pathological changes in the subchondral bone. In early OA, subchondral bone remodeling typically shifts to an increased bone resorption. However, as the disease progresses an increased bone formation takes place, leading to higher bone density with subsequent bone sclerosis. These changes can be influenced by different local or systemic factors. Recent evidence suggests that the autonomic nervous system (ANS) plays a role in regulating subchondral bone remodeling in OA. In this review, we 1) introduce bone structure and cellular mechanisms of bone remodeling in general, 2) explain the subchondral bone changes during OA pathogenesis, 3) then describe the contribution of the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS), the two major autonomic branches, to physiological subchondral bone remodeling, 4) followed by the influence of the SNS and PNS on subchondral bone remodeling in OA, and 5) finally, discuss the potential of therapeutic approaches targeting different components of the ANS.NEW & NOTEWORTHY The autonomic nervous system (ANS) with its two major branches, the sympathetic and parasympathetic nervous systems, plays a role in osteoarthritis pathogenesis by influencing bone structure and remodeling. We here review the current knowledge on subchondral bone remodeling with special regard to different bone cell types and underlying mechanisms at the cellular and molecular level. A better understanding of these mechanisms is needed for the development of novel OA treatment strategies targeting the ANS.


Assuntos
Cartilagem Articular , Osteoartrite , Humanos , Cartilagem Articular/patologia , Remodelação Óssea , Osso e Ossos/patologia , Inflamação/patologia
6.
Am J Hum Genet ; 107(5): 989-999, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33053334

RESUMO

Osteogenesis imperfecta (OI) is characterized primarily by susceptibility to fractures with or without bone deformation. OI is genetically heterogeneous: over 20 genetic causes are recognized. We identified bi-allelic pathogenic KDELR2 variants as a cause of OI in four families. KDELR2 encodes KDEL endoplasmic reticulum protein retention receptor 2, which recycles ER-resident proteins with a KDEL-like peptide from the cis-Golgi to the ER through COPI retrograde transport. Analysis of patient primary fibroblasts showed intracellular decrease of HSP47 and FKBP65 along with reduced procollagen type I in culture media. Electron microscopy identified an abnormal quality of secreted collagen fibrils with increased amount of HSP47 bound to monomeric and multimeric collagen molecules. Mapping the identified KDELR2 variants onto the crystal structure of G. gallus KDELR2 indicated that these lead to an inactive receptor resulting in impaired KDELR2-mediated Golgi-ER transport. Therefore, in KDELR2-deficient individuals, OI most likely occurs because of the inability of HSP47 to bind KDELR2 and dissociate from collagen type I. Instead, HSP47 remains bound to collagen molecules extracellularly, disrupting fiber formation. This highlights the importance of intracellular recycling of ER-resident molecular chaperones for collagen type I and bone metabolism and a crucial role of HSP47 in the KDELR2-associated pathogenic mechanism leading to OI.


Assuntos
Osso e Ossos/metabolismo , Colágeno Tipo I/metabolismo , Proteínas de Choque Térmico HSP47/metabolismo , Osteogênese Imperfeita/genética , Proteínas de Transporte Vesicular/metabolismo , Adulto , Alelos , Sequência de Aminoácidos , Animais , Sítios de Ligação , Osso e Ossos/patologia , Galinhas , Pré-Escolar , Colágeno Tipo I/química , Colágeno Tipo I/genética , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/patologia , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Expressão Gênica , Complexo de Golgi/metabolismo , Complexo de Golgi/patologia , Proteínas de Choque Térmico HSP47/química , Proteínas de Choque Térmico HSP47/genética , Humanos , Lactente , Masculino , Osteogênese Imperfeita/diagnóstico , Osteogênese Imperfeita/metabolismo , Osteogênese Imperfeita/patologia , Linhagem , Cultura Primária de Células , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Transporte Proteico , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/genética
7.
Int J Mol Sci ; 23(23)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36499685

RESUMO

Despite advanced knowledge of the cellular and biomechanical processes of intervertebral disc degeneration (IVDD), the trigger and underlying mechanisms remain unclear. Since the sympathetic nervous system (SNS) has been shown to exhibit catabolic effects in osteoarthritis pathogenesis, it is attractive to speculate that it also influences IVDD. Therefore, we explored the adrenoceptor (AR) expression profile in human IVDs and correlated it with clinical parameters of patients. IVD samples were collected from n = 43 patients undergoing lumbar spinal fusion surgery. AR gene expression was analyzed by semi-quantitative polymerase chain reaction. Clinical parameters as well as radiological Pfirrmann and Modic classification were collected and correlated with AR expression levels. In total human IVD homogenates α1A-, α1B-, α2A-, α2B-, α2C-, ß1- and ß2-AR genes were expressed. Expression of α1A- (r = 0.439), α2A- (r = 0.346) and ß2-AR (r = 0.409) showed a positive and significant correlation with Pfirrmann grade. α1A-AR expression was significantly decreased in IVD tissue of patients with adjacent segment disease (p = 0.041). The results of this study indicate that a relationship between IVDD and AR expression exists. Thus, the SNS and its neurotransmitters might play a role in IVDD pathogenesis. The knowledge of differential AR expression in different etiologies could contribute to the development of new therapeutic approaches for IVDD.


Assuntos
Degeneração do Disco Intervertebral , Disco Intervertebral , Fusão Vertebral , Humanos , Disco Intervertebral/metabolismo , Degeneração do Disco Intervertebral/metabolismo , Região Lombossacral , Receptores Adrenérgicos/metabolismo , Vértebras Lombares/metabolismo , Imageamento por Ressonância Magnética
8.
Int J Mol Sci ; 23(11)2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35682922

RESUMO

Matrix metalloproteinases (MMPs) play crucial roles in tissue homeostasis and pathologies by remodeling the extracellular matrix. Previous studies have demonstrated the biological activities of MMP-derived cleavage products. Furthermore, specific fragments can serve as biomarkers. Therefore, an in vitro cleavage assay to identify substrates and characterize cleavage patterns could provide important insight in disease-relevant mechanisms and the identification of novel biomarkers. In the pathogenesis of osteoarthritis (OA), MMP-2, -8, -9 and -13 are of vital importance. However, it is unclear which protease can cleave which matrix component. To address this question, we established an in vitro cleavage assay using recombinantly expressed MMPs and the two cartilage matrix components, COMP and thrombospondin-4. We found a time- and concentration-dependent degradation and an MMP-specific cleavage pattern for both proteins. Cleavage products can now be enriched and purified to investigate their biological activity. To verify the in vivo relevance, we compared the in vitro cleavage patterns with serum and synovial fluid from OA patients and could indeed detect fragments of similar size in the human samples. The cleavage assay can be adapted to other MMPs and substrates, making it a valuable tool for many research fields.


Assuntos
Metaloproteinases da Matriz , Osteoartrite , Biomarcadores/metabolismo , Cartilagem/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Humanos , Metaloproteinases da Matriz/metabolismo , Osteoartrite/metabolismo , Líquido Sinovial/metabolismo
9.
FASEB J ; 34(9): 12040-12052, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32716577

RESUMO

Although collagens are the most abundant proteins implicated in various disease pathways, essential mechanisms required for their proper folding and assembly are poorly understood. Heat-shock protein 47 (HSP47), an ER-resident chaperone, was mainly reported to fulfill key functions in folding and secretion of fibrillar collagens by stabilizing pro-collagen triple-helices. In this study, we demonstrate unique functions of HSP47 for different collagen subfamilies. Our results show that HSP47 binds to the N-terminal region of procollagen I and is essential for its secretion. However, HSP47 ablation does not majorly impact collagen VI secretion, but its lateral assembly. Moreover, specific ablation of Hsp47 in murine keratinocytes revealed a new role for the transmembrane collagen XVII triple-helix formation. Incompletely folded collagen XVII C-termini protruding from isolated HSP47 null keratinocyte membrane vesicles could be fully restored upon the application of recombinant HSP47. Thus, our study expands the current view regarding the client repertoire and function of HSP47, as well as emphasizes its importance for transmembrane collagen folding.


Assuntos
Proteínas de Choque Térmico HSP47/metabolismo , Queratinócitos/metabolismo , Pró-Colágeno/metabolismo , Dobramento de Proteína , Animais , Proteínas de Choque Térmico HSP47/genética , Camundongos , Pró-Colágeno/genética
10.
Int J Mol Sci ; 22(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668140

RESUMO

Osteoarthritis (OA) is a slow-progressing joint disease, leading to the degradation and remodeling of the cartilage extracellular matrix (ECM). The usually quiescent chondrocytes become reactivated and accumulate in cell clusters, become hypertrophic, and intensively produce not only degrading enzymes, but also ECM proteins, like the cartilage oligomeric matrix protein (COMP) and thrombospondin-4 (TSP-4). To date, the functional roles of these newly synthesized proteins in articular cartilage are still elusive. Therefore, we analyzed the involvement of both proteins in OA specific processes in in vitro studies, using porcine chondrocytes, isolated from femoral condyles. The effect of COMP and TSP-4 on chondrocyte migration was investigated in transwell assays and their potential to modulate the chondrocyte phenotype, protein synthesis and matrix formation by immunofluorescence staining and immunoblot. Our results demonstrate that COMP could attract chondrocytes and may contribute to a repopulation of damaged cartilage areas, while TSP-4 did not affect this process. In contrast, both proteins similarly promoted the synthesis and matrix formation of collagen II, IX, XII and proteoglycans, but inhibited that of collagen I and X, resulting in a stabilized chondrocyte phenotype. These data suggest that COMP and TSP-4 activate mechanisms to protect and repair the ECM in articular cartilage.


Assuntos
Artrite Experimental/metabolismo , Proteína de Matriz Oligomérica de Cartilagem/metabolismo , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Matriz Extracelular/metabolismo , Osteoartrite/metabolismo , Trombospondinas/metabolismo , Animais , Artrite Experimental/patologia , Cartilagem Articular/patologia , Condrócitos/patologia , Feminino , Osteoartrite/patologia , Suínos
11.
Int J Mol Sci ; 22(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34298867

RESUMO

The hexosamine biosynthetic pathway (HBP) is essential for the production of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), the building block of glycosaminoglycans, thus playing a crucial role in cartilage anabolism. Although O-GlcNAcylation represents a protective regulatory mechanism in cellular processes, it has been associated with degenerative diseases, including osteoarthritis (OA). The present study focuses on HBP-related processes as potential therapeutic targets after cartilage trauma. Human cartilage explants were traumatized and treated with GlcNAc or glucosamine sulfate (GS); PUGNAc, an inhibitor of O-GlcNAcase; or azaserine (AZA), an inhibitor of GFAT-1. After 7 days, cell viability and gene expression analysis of anabolic and catabolic markers, as well as HBP-related enzymes, were performed. Moreover, expression of catabolic enzymes and type II collagen (COL2) biosynthesis were determined. Proteoglycan content was assessed after 14 days. Cartilage trauma led to a dysbalanced expression of different HBP-related enzymes, comparable to the situation in highly degenerated tissue. While GlcNAc and PUGNAc resulted in significant cell protection after trauma, only PUGNAc increased COL2 biosynthesis. Moreover, PUGNAc and both glucosamine derivatives had anti-catabolic effects. In contrast, AZA increased catabolic processes. Overall, "fueling" the HBP by means of glucosamine derivatives or inhibition of deglycosylation turned out as cells and chondroprotectives after cartilage trauma.


Assuntos
Vias Biossintéticas/efeitos dos fármacos , Doenças das Cartilagens/tratamento farmacológico , Condrócitos/efeitos dos fármacos , Condrócitos/metabolismo , Glucosamina/farmacologia , Hexosaminas/metabolismo , Uridina Difosfato N-Acetilglicosamina/farmacologia , Biomarcadores/metabolismo , Cartilagem/efeitos dos fármacos , Cartilagem/metabolismo , Doenças das Cartilagens/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Colágeno Tipo II/metabolismo , Feminino , Expressão Gênica/efeitos dos fármacos , Glicosilação/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/tratamento farmacológico , Osteoartrite/metabolismo , Fosforilação/efeitos dos fármacos
12.
Int J Mol Sci ; 22(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34445661

RESUMO

Exogenous adenosine and its metabolite inosine exert anti-inflammatory effects in synoviocytes of osteoarthritis (OA) and rheumatoid arthritis (RA) patients. We analyzed whether these cells are able to synthesize adenosine/inosine and which adenosine receptors (ARs) contribute to anti-inflammatory effects. The functionality of synthesizing enzymes and ARs was tested using agonists/antagonists. Both OA and RA cells expressed CD39 (converts ATP to AMP), CD73 (converts AMP to adenosine), ADA (converts adenosine to inosine), ENT1/2 (adenosine transporters), all AR subtypes (A1, A2A, A2B and A3) and synthesized predominantly adenosine. The CD73 inhibitor AMPCP significantly increased IL-6 and decreased IL-10 in both cell types, while TNF only increased in RA cells. The ADA inhibitor DAA significantly reduced IL-6 and induced IL-10 in both OA and RA cells. The A2AAR agonist CGS 21680 significantly inhibited IL-6 and induced TNF and IL-10 only in RA, while the A2BAR agonist BAY 60-6583 had the same effect in both OA and RA. Taken together, OA and RA synoviocytes express the complete enzymatic machinery to synthesize adenosine/inosine; however, mainly adenosine is responsible for the anti- (IL-6 and IL-10) or pro-inflammatory (TNF) effects mediated by A2A- and A2BAR. Stimulating CD39/CD73 with simultaneous ADA blockage in addition to TNF inhibition might represent a promising therapeutic strategy.


Assuntos
Adenosina/farmacologia , Anti-Inflamatórios/farmacologia , Artrite Reumatoide/tratamento farmacológico , Osteoartrite/tratamento farmacológico , Membrana Sinovial/efeitos dos fármacos , Sinoviócitos/efeitos dos fármacos , Vasodilatadores/farmacologia , Idoso , Idoso de 80 Anos ou mais , Artrite Reumatoide/metabolismo , Artrite Reumatoide/patologia , Citocinas/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/metabolismo , Osteoartrite/patologia , Sinoviócitos/metabolismo , Sinoviócitos/patologia
13.
Int J Mol Sci ; 22(6)2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33802838

RESUMO

Osteoarthritis (OA) is a multifactorial disease which is characterized by a change in the homeostasis of the extracellular matrix (ECM). The ECM is essential for the function of the articular cartilage and plays an important role in cartilage mechanotransduction. To provide a better understanding of the interaction between the ECM and the actin cytoskeleton, we investigated the localization and expression of the Ca2+-dependent proteins cartilage oligomeric matrix protein (COMP), thrombospondin-1 (TSP-1), plastin 3 (PLS3) and stromal interaction molecule 1 (STIM1). We investigated 16 patients who suffered from varus knee OA and performed a topographical analysis of the cartilage from the medial and lateral compartment of the proximal tibial plateau. In a varus knee, OA is more pronounced in the medial compared to the lateral compartment as a result of an overloading due to the malalignment. We detected a location-dependent staining of PLS3 and STIM1 in the articular cartilage tissue. The staining intensity for both proteins correlated with the degree of cartilage degeneration. The staining intensity of TSP-1 was clearly reduced in the cartilage of the more affected medial compartment, an observation that was confirmed in cartilage extracts by immunoblotting. The total amount of COMP was unchanged; however, slight changes were detected in the localization of the protein. Our results provide novel information on alterations in OA cartilage suggesting that Ca2+-dependent mechanotransduction between the ECM and the actin cytoskeleton might play an essential role in the pathomechanism of OA.


Assuntos
Cartilagem Articular/metabolismo , Articulação do Joelho/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/metabolismo , Osteoartrite do Joelho/metabolismo , Molécula 1 de Interação Estromal/metabolismo , Trombospondinas/metabolismo , Idoso , Idoso de 80 Anos ou mais , Proteína de Matriz Oligomérica de Cartilagem/metabolismo , Condrócitos/metabolismo , Feminino , Humanos , Articulação do Joelho/patologia , Masculino , Pessoa de Meia-Idade , Osteoartrite do Joelho/patologia , Transporte Proteico
14.
Hum Mol Genet ; 27(24): 4249-4262, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30204862

RESUMO

Over 200 million people suffer from osteoporosis worldwide, one third of which will develop osteoporotic bone fractures. Unfortunately, no effective cure exists. Mutations in plastin 3 (PLS3), an F-actin binding and bundling protein, cause X-linked primary osteoporosis in men and predisposition to osteoporosis in postmenopausal women. Moreover, the strongest association so far for osteoporosis in elderly women after menopause was connected to a rare SNP in PLS3, indicating a possible role of PLS3 in complex osteoporosis as well. Interestingly, 5% of the general population are overexpressing PLS3, with yet unknown consequences. Here, we studied ubiquitous Pls3 knockout and PLS3 overexpression in mice and demonstrate that both conditions influence bone remodeling and structure: while Pls3 knockout mice exhibit osteoporosis, PLS3 overexpressing mice show thickening of cortical bone and increased bone strength. We show that unbalanced PLS3 levels affect osteoclast development and function, by misregulating the NFκB pathway. We found upregulation of RELA (NFκB subunit p65) in PLS3 overexpressing mice-known to stimulate osteoclastogenesis-but strikingly reduced osteoclast resorption. We identify NFκB repressing factor (NKRF) as a novel PLS3 interactor, which increasingly translocates to the nucleus when PLS3 is overexpressed. We show that NKRF binds to the NFκB downstream target and master regulator of osteoclastogenesis nuclear factor of activated T cells 1 (Nfatc1), thereby reducing its transcription and suppressing osteoclast function. We found the opposite in Pls3 knockout osteoclasts, where decreased nuclear NKRF augmented Nfatc1 transcription, causing osteoporosis. Regulation of osteoclastogenesis and bone remodeling via the PLS3-NKRF-NFκB-NFATC1 axis unveils a novel possibility to counteract osteoporosis.


Assuntos
Glicoproteínas de Membrana/genética , Proteínas dos Microfilamentos/genética , Fatores de Transcrição NFATC/genética , Osteogênese/genética , Osteoporose/genética , Animais , Densidade Óssea/genética , Remodelação Óssea/genética , Modelos Animais de Doenças , Fraturas Ósseas/genética , Fraturas Ósseas/patologia , Humanos , Camundongos , Mutação , Osteoclastos/metabolismo , Osteoclastos/patologia , Osteoporose/fisiopatologia , Proteínas Repressoras/genética , Fator de Transcrição RelA/genética
15.
J Immunol ; 201(2): 663-674, 2018 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-29898959

RESUMO

Myeloid cells can be beneficial as well as harmful in tissue regenerative responses. The molecular mechanisms by which myeloid cells control this critical decision of the immune system are not well understood. Using two different models of physiological acute or pathological chronic skin damage, in this study we identified myeloid cell-restricted STAT3 signaling as important and an injury context-dependent regulator of skin fibrosis. Targeted disruption of STAT3 signaling in myeloid cells significantly accelerated development of pathological skin fibrosis in a model of chronic bleomycin-induced tissue injury, whereas the impact on wound closure dynamics and quality of healing after acute excision skin injury was minor. Chronic bleomycin-mediated tissue damage in control mice provoked an antifibrotic gene signature in macrophages that was characterized by upregulated expression of IL-10, SOCS3, and decorin. In contrast, in STAT3-deficient macrophages this antifibrotic repair program was abolished whereas TGF-ß1 expression was increased. Notably, TGF-ß1 synthesis in cultured control bone marrow-derived macrophages (BMDMs) was suppressed after IL-10 exposure, and this suppressive effect was alleviated by STAT3 deficiency. Accordingly, coculture of IL-10-stimulated control BMDMs with fibroblasts suppressed expression of the TGF-ß1 downstream target connective tissue growth factor in fibroblasts, whereas this suppressive effect was lost by STAT3 deficiency in BMDMs. Our findings highlight a previously unrecognized protective role of myeloid cell-specific STAT3 signaling in immune cell-mediated skin fibrosis, and its regulatory pathway could be a potential target for therapy.


Assuntos
Macrófagos/imunologia , Células Mieloides/fisiologia , Fator de Transcrição STAT3/metabolismo , Dermatopatias/imunologia , Pele/patologia , Doença Aguda , Animais , Células Cultivadas , Doença Crônica , Modelos Animais de Doenças , Fibrose , Interleucina-10/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regeneração , Fator de Transcrição STAT3/genética , Transdução de Sinais , Dermatopatias/induzido quimicamente , Transcriptoma , Fator de Crescimento Transformador beta/metabolismo , Cicatrização
16.
Int J Mol Sci ; 21(11)2020 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-32486305

RESUMO

Bone marrow-derived mesenchymal stem cells (BMSCs) represent an alternative to chondrocytes to support cartilage regeneration in osteoarthritis (OA). The sympathetic neurotransmitter norepinephrine (NE) has been shown to inhibit their chondrogenic potential; however, their proliferation capacity under NE influence has not been studied yet. Therefore, we used BMSCs obtained from trauma and OA donors and compared the expression of adrenergic receptors (AR). Then, BMSCs from both donor groups were treated with NE, as well as with combinations of NE and α1-, α2- or ß1/2-AR antagonists (doxazosin, yohimbine or propranolol). Activation of AR-coupled signaling was investigated by analyzing ERK1/2 and protein kinase A (PKA) phosphorylation. A similar but not identical subset of ARs was expressed in trauma (α2B-, α2C- and ß2-AR) and OA BMSCs (α2A-, α2B-, and ß2-AR). NE in high concentrations inhibited the proliferation of both trauma and OA BMCSs significantly. NE in low concentrations did not influence proliferation. ERK1/2 as well as PKA were activated after NE treatment in both BMSC types. These effects were abolished only by propranolol. Our results demonstrate that NE inhibits the proliferation and accordingly lowers the regenerative capacity of human BMSCs likely via ß2-AR-mediated ERK1/2 and PKA phosphorylation. Therefore, targeting ß2-AR-signaling might provide novel OA therapeutic options.


Assuntos
Proliferação de Células/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Norepinefrina/farmacologia , Receptores Adrenérgicos beta 2/metabolismo , Adulto , Idoso , Células da Medula Óssea/citologia , Sobrevivência Celular , Células Cultivadas , Condrócitos/citologia , Doxazossina/farmacologia , Feminino , Perfilação da Expressão Gênica , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Células-Tronco Mesenquimais/citologia , Pessoa de Meia-Idade , Neurotransmissores/metabolismo , Fosforilação , Propranolol/farmacologia , Transdução de Sinais , Ioimbina/farmacologia , Adulto Jovem
17.
Int J Mol Sci ; 21(11)2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32526967

RESUMO

MicroRNAs (miRNAs) regulate cartilage differentiation and contribute to the onset and progression of joint degeneration. These small RNA molecules may affect extracellular matrix organization (ECM) in cartilage, but for only a few miRNAs has this role been defined in vivo. Previously, we showed that cartilage-specific genetic ablation of the Mirc24 cluster in mice leads to impaired cartilage development due to increased RAF/MEK/ERK pathway activation. Here, we studied the expression of the cluster in cartilage by LacZ reporter gene assays and determined its role for extracellular matrix homeostasis by proteome and immunoblot analysis. The cluster is expressed in prehypertrophic/hypertrophic chondrocytes of the growth plate and we now show that the cluster is also highly expressed in articular cartilage. Cartilage-specific loss of the cluster leads to increased proteoglycan 4 and matrix metallopeptidase 13 levels and decreased aggrecan and collagen X levels in epiphyseal cartilage. Interestingly, these changes are linked to a decrease in SRY-related HMG box-containing (SOX) transcription factors 6 and 9, which regulate ECM production in chondrocytes. Our data suggests that the Mirc24 cluster is important for ECM homoeostasis and the expression of transcriptional regulators of matrix production in cartilage.


Assuntos
Cartilagem Articular/metabolismo , Proteínas da Matriz Extracelular/genética , MicroRNAs/genética , Osteoartrite/genética , Animais , Cartilagem Articular/fisiologia , Colágeno Tipo II/genética , Proteínas da Matriz Extracelular/metabolismo , Regulação da Expressão Gênica , Lâmina de Crescimento/química , Masculino , Metaloproteinase 13 da Matriz/genética , Metaloproteinase 13 da Matriz/metabolismo , Camundongos Transgênicos , Família Multigênica , Proteoglicanas/genética , Proteoglicanas/metabolismo , Fatores de Transcrição SOX9/genética , Fatores de Transcrição SOX9/metabolismo , Fatores de Transcrição SOXD/genética , Fatores de Transcrição SOXD/metabolismo
18.
Int J Mol Sci ; 21(6)2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32197418

RESUMO

Healthy and degenerating intervertebral discs (IVDs) are innervated by sympathetic nerves, however, adrenoceptor (AR) expression and functionality have never been investigated systematically. Therefore, AR gene expression was analyzed in both tissue and isolated cells from degenerated human IVDs. Furthermore, human IVD samples and spine sections of wildtype mice (WT) and of a mouse line that develops spontaneous IVD degeneration (IVDD, in SM/J mice) were stained for ARs and extracellular matrix (ECM) components. In IVD homogenates and cells α1a-, α1b-, α2a-, α2b-, α2c-, ß1-, and ß2-AR genes were expressed. In human sections, ß2-AR was detectable, and its localization parallels with ECM alterations. Similarly, in IVDs of WT mice, only ß2-AR was expressed, and in IVDs of SM/J mice, ß2AR expression was stronger accompanied by increased collagen II, collagen XII, decorin as well as decreased cartilage oligomeric matrix protein expression. In addition, norepinephrine stimulation of isolated human IVD cells induced intracellular signaling via ERK1/2 and PKA. For the first time, the existence and functionality of ARs were demonstrated in IVD tissue samples, suggesting that the sympathicus might play a role in IVDD. Further studies will address relevant cellular mechanisms and thereby help to develop novel therapeutic options for IVDD.


Assuntos
Regulação da Expressão Gênica , Degeneração do Disco Intervertebral/metabolismo , Sistema de Sinalização das MAP Quinases , Receptores Adrenérgicos/biossíntese , Idoso , Animais , Feminino , Humanos , Degeneração do Disco Intervertebral/patologia , Masculino , Camundongos , Camundongos Transgênicos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo
19.
Am J Physiol Cell Physiol ; 326(3): C659-C660, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38252506

Assuntos
Bioengenharia , Biologia
20.
Clin Exp Rheumatol ; 37(3): 450-457, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30557125

RESUMO

OBJECTIVES: Tryptophan and its metabolites have been suggested to play a role in inflammatory processes. However, studies in rheumatoid arthritis (RA) are scarce, which prompted us to investigate two cohorts of RA patients to better understand the importance of tryptophan metabolism in this disease. METHODS: Tryptophan and its metabolites were characterised by ELISA in a cross-sectional cohort 1 (81 RA, 55 OA) and a longitudinal cohort 2 (25 RA, 3 visits over 6 months) to investigate discriminatory power between diseases and predicitive value for radiologic outcome, respectively. Radiologic outcome was monitored by RA MRI Score (RAMRIS), including grading of synovitis, bone oedema and erosion, as well as delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) index assessing cartilage quality of the MCP II joint. RESULTS: RA patients showed higher levels of serum serotonin (RA: 206.8 ng/ml ± 156.7; OA: 81.2 ng/ml ± 63.6) and estimated indoleamine (2,3)-dioxygenase (IDO) activity (kynurenine / tryptophan ratio; RA: 0.065±0.067; OA: 0.021±0.010). IDO activity showed similar, or better discriminatory power between RA and OA (AUC 0.914) than anti-CCP antibody level (AUC 0.922) and rheumatoid factor (RF, AUC 0.783), respectively. In cohort 2, regression analysis revealed a predictive value of baseline serotonin levels and IDO activity for changes in RAMRIS score and erosions at month six, respectively. CONCLUSIONS: This study supports the hypothesis that tryptophan and its metabolites can be used as biomarkers predicting radiologic outcome and discriminate between RA and OA patients. Overall, our results strengthen the notion that tryptophan metabolism is closely linked to RA disease mechanisms.


Assuntos
Artrite Reumatoide/metabolismo , Imageamento por Ressonância Magnética/métodos , Fator Reumatoide , Sinovite , Triptofano/metabolismo , Artrite Reumatoide/diagnóstico por imagem , Artrite Reumatoide/patologia , Estudos Transversais , Humanos , Osteoartrite/diagnóstico por imagem , Osteoartrite/metabolismo
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