Gene expression profiles of the meniscus avascular phenotype: A guide for meniscus tissue engineering

Abstract

Avascular (Avas) meniscus regeneration remains a challenge, which is partly a consequence of our limited knowledge of the cells that maintain this tissue region. In this study, we utilized microarrays to characterize gene expression profiles of intact human Avas meniscus tissue and of cells following culture expansion. Using these data, we examined various 3D culture conditions to redifferentiate Avas cells toward the tissue phenotype. RNA was isolated from either the tissue directly or following cell isolation and 2 weeks in monolayer culture. RNA was hybridized on human genome arrays. Differentially expressed (DE) genes were identified by ranking analysis. DAVID pathway analysis was performed and visualized using STRING analysis. Quantitative PCR (qPCR) on additional donor menisci (tissues and cells) were used to validate array data. Avas cells cultured in 3D were subjected to qPCR to compare with the array-generated data. A total of 387 genes were DE based on differentiation state (>3-fold change; p < 0.01). In Avas-cultured cells, the upregulated pathways included focal adhesion, ECM-receptor interaction, regulation of actin cytoskeleton, and PDGF Signaling. In 3D-cultured Avas cells, TGFβ1 or combinations of TGFβ1 and BMP6 were most effective to promote an Avas tissue phenotype. THBS2 and THBS4 expression levels were identified as a means to denote meniscus cell phenotype status. We identified the key gene expression profiles, new markers and pathways involved in characterizing the Avas meniscus phenotype in the native state and during in vitro dedifferentiation and redifferentiation. These data served to screen 3D conditions to generate meniscus-like neotissues. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1947-1958, 2018.

Human engineered meniscus transcriptome after short-term combined hypoxia and dynamic compression

“…[29][30][31][32] Candidate gene biomarkers of the human inner avascular meniscus have been characterized relative to expanded and re-differentiated MFCs. 33 Chondroadherin (CHAD), which encodes a cartilage matrix adhesion-related protein, showed wide expression differences within that study and in the present work between the fibrous and hyaline-like donors (11-fold upregulation) with M/24y as the intermediate, suggesting its expression in tissue may provide early knowledge of a donor's downstream matrix forming capacity. Similar methods to predict the matrix-forming capacity of a donor's cells at an early stage may facilitate eventual clinical translation of meniscus tissue engineering-related technology.…”

Pharmacological blockade of PCAF ameliorates osteoarthritis development via dual inhibition of TNF-α-driven inflammation and ER stress

“…Firstly, studies showed that chondrocytes undergo a process of dedifferentiation in monolayer culture that is characterized by a transition to a fibroblast-like phenotype [60]. Thus in order to prevent phenotypic feature loss, passage 1–3 chondrocytes were used in our most studies.3D culture may offer a possible way to the maintenance of cartilaginous gene expression on extracellular matrix [61], which would be applied for our further study. Secondly, Destabilization of medial meniscus (DMM) model is used in our study, which is also the most commonly used surgical model for OA in mice currently.…”

Transcriptome Sequencing Reveals Sex Differences in Human Meniscal Cell Response to Estrogen Based on Dosing Kinetics

“…A number of microarray and sequencing studies have provided important insight on transcriptome differences in the meniscus including avascular meniscus that heals poorly, 39 in meniscus from patients with and without osteoarthritis, 40 the progenitor cell phenotype that may reduce osteoarthritis, 41 and single-cell sequencing to define unique meniscal progenitor populations that are critical to maintain tissue health and reduce degeneration. 42 Building off this body of work, this study focuses on transcriptome differences between male and female tissue that will inform sex differences in natural aging and inform the role of sex hormones in repair and homeostasis.…”

“…There are limitations to the current study that should be considered. This study was performed using 2D culture methods, which are known to promote a more fibroblast-like phenotype of the meniscal fibrochondrocytes 39; 55 and thus will indicate more of the fibroblast-like cell response to estrogen. Additionally, this study was performed using cells isolated from only 2 donors, both 47-years old.…”