An integrated in silico-in vitro approach for identifying therapeutic targets against osteoarthritis.

BACKGROUND: Without the availability of disease-modifying drugs, there is an unmet therapeutic need for osteoarthritic patients. During osteoarthritis, the homeostasis of articular chondrocytes is dysregulated and a phenotypical transition called hypertrophy occurs, leading to cartilage degeneration. Targeting this phenotypic transition has emerged as a potential therapeutic strategy. Chondrocyte phenotype maintenance and switch are controlled by an intricate network of intracellular factors, each influenced by a myriad of feedback mechanisms, making it challenging to intuitively predict treatment outcomes, while in silico modeling can help unravel that complexity. In this study, we aim to develop a virtual articular chondrocyte to guide experiments in order to rationalize the identification of potential drug targets via screening of combination therapies through computational modeling and simulations. RESULTS: We developed a signal transduction network model using knowledge-based and data-driven (machine learning) modeling technologies. The in silico high-throughput screening of (pairwise) perturbations operated with that network model highlighted conditions potentially affecting the hypertrophic switch. A selection of promising combinations was further tested in a murine cell line and primary human chondrocytes, which notably highlighted a previously unreported synergistic effect between the protein kinase A and the fibroblast growth factor receptor 1. CONCLUSIONS: Here, we provide a virtual articular chondrocyte in the form of a signal transduction interactive knowledge base and of an executable computational model. Our in silico-in vitro strategy opens new routes for developing osteoarthritis targeting therapies by refining the early stages of drug target discovery.

Intra-articular injection of triamcinolone acetonide sustains macrophage levels and aggravates osteophytosis during degenerative joint disease in mice.

BACKGROUND AND PURPOSE: Corticosteroids such as triamcinolone acetonide (TAA) are potent drugs administered intra-articularly as an anti-inflammatory therapy to relieve pain associated with osteoarthritis (OA). However, the ability of early TAA intervention to mitigate OA progression and modulate immune cell subsets remains unclear. Here, we sought to understand the effect of early intra-articular injection of TAA on OA progression, local macrophages, and peripheral blood monocytes. EXPERIMENTAL APPROACH: Degenerative joint disease was induced by intra-articular injection of collagenase into the knee joint of male C57BL/6 mice. After 1 week, TAA or saline was injected intra-articularly. Blood was taken throughout the study to analyse monocyte subsets. Mice were killed at days 14 and 56 post-induction of collagenase-induced OA (CiOA) to examine synovial macrophages and structural OA features. KEY RESULTS: The percentage of macrophages relative to total live cells present within knee joints was increased in collagenase- compared with saline-injected knees at day 14 and was not altered by TAA treatment. However, at day 56, post-induction of CiOA, TAA-treated knees had increased levels of macrophages compared with the knees of untreated CiOA-mice. The distribution of monocyte subsets present in peripheral blood was not altered by TAA treatment during the development of CiOA. Osteophyte maturation was increased in TAA-injected knees at day 56. CONCLUSION AND IMPLICATIONS: Intra-articular injection of TAA increases long-term synovial macrophage numbers and osteophytosis. Our findings suggest that TAA accentuates the progression of osteoarthritis-associated features when applied to an acutely inflamed knee.

Effect of Inflammatory Signaling on Human Articular Chondrocyte Hypertrophy: Potential Involvement of Tissue Repair Macrophages.

OBJECTIVE: In osteoarthritis, chondrocytes tend to acquire a hypertrophic phenotype, which contributes to the modification of the extracellular matrix, resulting in permanent cartilage changes. In mouse chondrocytes, pro-inflammatory macrophages and pro-inflammatory cytokines have been shown to stimulate hypertrophy via the activation of the nuclear factor kappa B (NF-κB) pathway. Whether or not this also occurs in human chondrocytes remains unclear. We therefore aimed to investigate whether hypertrophy-like responses in human cartilage are driven mainly by intrinsic inflammatory signaling or shaped by specific macrophage populations. DESIGN: Human articular chondrocytes were cultured with pro-inflammatory cytokines or medium conditioned by defined macrophage subsets. Furthermore, the effect of inhibition of NF-κB-dependent gene expression was evaluated using the NF-κB inhibitor SC-514. Hypertrophy was assessed by measuring the transcription level of alkaline phosphatase (ALPL), type X collagen (COL10A1), Indian hedgehog (IHH), and runt-related transcription factor 2 (RUNX2). RESULTS: The expression of hypertrophic genes was not promoted in human chondrocytes by pro-inflammatory cytokines neither pro-inflammatory M(IFNγ + TNFα) macrophages. Inhibition of the NF-κB-dependent gene expression did not affect human articular chondrocyte hypertrophy. However, tissue repair M(IL4) macrophages induced hypertrophy by promoting the expression of COL10A1, RUNX2, and IHH. CONCLUSION: Intrinsic inflammatory signaling activation is not involved in the hypertrophic shift observed in human articular chondrocytes cultured in vitro. However, tissue repair macrophages may contribute to the onset of this detrimental phenotype in human osteoarthritic cartilage, given the effect observed in our experimental models.

Etapas da elaboração do Instrumento de Classificação do Grau de Funcionalidade de Pessoas com Deficiência para Cidadãos Brasileiros: Índice de Funcionalidade Brasileiro - IF-Br / Development of a grading instrument of functioning for Brazilian citizens: Brazilian Functioning Index - IF-Br

Os sistemas usados no Brasil para definir a incapacidade variam de acordo com o setor. A partir de uma recomendação da Presidência da República, uma força-tarefa interministerial foi organizada em janeiro de 2011 para desenvolver um modelo único de avaliação e classificação da incapacidade a ser usado em todo o país. O grupo de trabalho partiu de uma avaliação ampla de informações biodemográficas das pessoas com deficiência no Brasil obtidas a partir de fontes como o censo populacional, censo escolar, relação anual de informações sociais e pesquisa de informações básicas municipais, bem como grupos focais realizados com representantes de vários estados da federação, diferentes deficiências e faixas etárias. Por meio de reuniões mensais num período de 8 meses, foi escolhido o modelo conceitual da Classificação Internacional de Deficiências, Incapacidades e Saúde como base teórica e partir do qual foram selecionadas as 41 atividades e fatores ambientais que deveriam ser contemplados no em cada uma delas. A pontuação de cada atividade foi definida numa escala de 25 a 100, de acordo com o nível de independência. Ajustes para crianças foram realizados comparando o instrumento ao desenvolvimento esperado para cada faixa etária de acordo com a descrição presente em outros instrumentos. Além da avaliação quantitativa do grau de incapacidade, foi desenvolvida uma avaliação qualitativa seguindo a lógica fuzzy, específica para as deficiências visual, motora, auditiva e intelectual. A definição de notas de corte não foi efetuada e exige estudos futuros.

The systems used for disability certification in Brazil vary according to the sectors. By recommendation from the Presidency of the Republic, an interministerial task force was organized in January 2011 to develop a single model evaluation and classification of disability to be used throughout the country. The working group began with a comprehensive review of biodemographic information of people with disabilities in Brazil, obtained from sources such as the national census, school census, annual list of social information and research of municipal basic information, as well as focus groups with representatives various states of the federation, as well as data collected from focus groups performed with different disabilities and age groups. Through monthly meetings over a period of eight months, the conceptual model of the International Classification of Impairments, Disability and Health was have chosen as a theoretical basis and from which the 41 activities were selected and the environmental factors should be assessed in each of them. The score was defined for each activity in a ratio from 25 to 100, depending on the level of independence. Adjustments were made for children comparing the expected development for each age group according to the description found in other instruments. In addition to the quantitative assessment of the degree of disability, another questionnaire was developed following a qualitative fuzzy logic, which were specific for visual, motor, auditory and intellectual impairments. The definition of cutoff scores was not performed and requires further study.