A Protocol to Prepare Decellularized Stem Cell Matrix for Rejuvenation of Cell Expansion and Cartilage Regeneration

Laminin expression profiles of osteogenic-and chondrogenic-induced dECM sheets

Decellularized extracellular matrix sheets (dECMSs) produced by stem cells have attracted attention because they preserve the natural biological activity of the ECM to direct lineage-specific differentiation with less immunogenicity. As a core ECM protein, laminin modulates cellular phenotype and differentiation. Nevertheless, no studies thus far have explored the distribution and abundance of laminins in diverse dECMSs. Herein, we first compared the differential expression of laminins among dECMSs in osteogenic-induced medium (OI-dECMS), chondrogenic-induced medium (CI-dECMS), and standard medium (dECMS), employing a defined mass spectrometry (MS)-based proteomic analysis. In vitro, dECMSs were verified to be successfully decellularized. Cluster analysis identified a marked fluctuation in the expression of 7 laminins and 17 laminin-associated proteins in OI-dECMS vs dECMS and CI-dECMS vs dECMS. Two significantly changed pathways were selected from the KEGG pathway enrichment analysis: the FAK/ERK pathway and the PI3K/AKT pathway. Moreover, Alkaline Phosphatase (ALP) activity, Alcian blue staining, and RT-qPCR results for recellularization showed that CI-dECMS promotes chondrogenesis while OI-dECMS inhibits osteogenesis compared with dECMS. In vivo experiments were conducted to implant dECMSs in a rat osteochondral defect, demonstrating that dECMS and CI-dECMS promoted bone and cartilage repair. Furthermore, the inhibitory analysis was performed to verify the function of specific laminin isoforms modulating osteogenesis and chondrogenesis, which might be related to FAK/ERK and PI3K/AKT pathways. In summary, this study constructed dECMS, OI-dECMS, and CI-dECMS and uncovered the internal comprehensive molecular regulatory network centralized by laminins, thus proposing a biomimetic substitute for bone and cartilage regeneration.

A comparative analysis of stem cells derived from young rabbit knee joints: the potentially superior performance of decellularized extracellular matrix pretreated infrapatellar fat pad stem cells on nanofiber scaffolds

Introduction

Osteoarthritis (OA) remains a significant clinical challenge, necessitating improved strategies for cartilage repair. Stem cells and scaffolds have crucial roles in tissue repair and regeneration. In this study, we comprehensively investigated the proliferation and differentiation potential of infrapatellar fat pad stem cells (IFPSCs), synovium-derived stem cells (SDSCs), and bone marrow stem cells (BMSCs) from unpretreated knee joints in young rabbits, and after decellularized extracellular matrix (dECM) deposition by stem cell pretreatment in vitro.

Methods

We also examined adhesion and differentiation effects of poly-L-lactic acid (PLLA) and poly-D, L-lactic acid (PDLLA) scaffolds after inoculation with the three stem cell types. We conducted osteogenic, adipogenic, and chondrogenic induction studies using three unpretreated stem cell groups, nine stem cell groups cross-preconditioned with different dECM types, and six stem cell groups cultured on nanofiber PLLA and PDLLA scaffolds. Staining and PCR analyses were then performed.

Results

In vitro studies indicated that without pretreatment, IFPSCs exhibited the highest proliferation capacity, followed by SDSCs, while BMSCs had the lowest proliferation rate. After cross-pretreatment with dECMs from different sources, IFPSCs pretreated with IECM (decellularized extracellular matrix deposited by IFPSCs) showed the greatest proliferation. BMSCs displayed the highest osteogenic potential, while SDSCs and IFPSCs showed greater chondrogenic potential. No significant differences were observed in adipogenic potential among the three groups. BMSCs exhibited reduced osteogenic potential after pretreatment with all three dECMs, whereas IFPSCs and SDSCs showed enhanced osteogenic potential following SECM and IECM pretreatment, respectively. Additionally, all 3 cell types showed reduced lipogenic potential after pretreatment with the three dECM types. For chondrogenesis, BECM pretreatment were suitable for enhancing the chondrogenic potential of all 3 cell types. Furthermore, BMSCs and IFPSCs exhibited better adhesion and survival than SDSCs on electrospun scaffolds, which mimicked dECM structures. Besides, BMSCs and IFPSCs are more suitable for PLLA to promote osteogenic, adipogenic, and chondrogenic differentiation, whereas SDSCs are better suited for PDLLA.

Discussion

Overall, it is anticipated that IFPSCs can be expanded with BECM pretreatment in vitro, and when combined with degradable nanofiber PLLA scaffolds in vivo, will facilitate better OA repair.

Distinct role of perlecan in mesenchymal tissue regeneration via genetic and epigenetic modification

Perlecan (HSPG2), a key component of basement membrane proteins, plays a crucial role in tissue development and regeneration. However, its direct impact on mesenchymal tissue differentiation, mediated through both genetic modification (gain- and loss-of-function mutations) and epigenetic changes (matrix microenvironment alterations), remains underexplored. In this study, we utilized CRISPR/Cas9 to achieve knockout (KO) and overexpression (OE) of HSPG2 in human fetal nucleus pulposus stem/progenitor cells (NPSCs) and adult infrapatellar fat pad-derived stem cells (IPFSCs) to investigate perlecan's influence on mesenchymal differentiation. We also assessed the effects of decellularized extracellular matrix (dECM) derived from fetal NPSCs with modified HSPG2 expression on the proliferation and differentiation of adult NPSCs. Our findings demonstrate that HSPG2-KO enhance chondrogenic differentiation, while HSPG2-OE suppressed adipogenic differentiation in both fetal NPSCs and adult IPFSCs. Notably, dECM from HSPG2-OE fetal NPSCs significantly promoted chondrogenic differentiation in adult NPSCs, suggesting potential applications for perlecan in developing advanced biomaterials for cartilage regeneration.

Modulation of Canine Adipose-Derived Mesenchymal Stem/Medicinal Signalling Cells with Ascorbic Acid: Effect on Proliferation and Chondrogenic Differentiation on Standard Plastic and Silk Fibroin Surfaces

Ascorbic acid (AA) plays a crucial role in both the proliferation and chondrogenic differentiation potential of mesenchymal stem/medicinal signalling cells (MSCs); these are both key aspects of their general therapeutic use and their increasing use in veterinary medicine. Current immunomodulatory therapies require efficient expansion of MSCs in the laboratory, while emerging tissue regeneration strategies, such as cartilage or bone repair, aim to use differentiated MSCs and modulate the expression of chondrogenic and hypertrophic markers. Our aim was to investigate whether the addition of AA to the growth medium enhances the proliferation of canine adipose-derived MSCs (cAMSCs) grown on standard plastic surfaces and whether it affects chondrogenic differentiation potential on silk fibroin (SF) films. We assessed cell viability with trypan blue and proliferation potential by calculating population doubling. Chondrogenic induction on SF films was assessed by Alcian blue staining and gene expression analysis of chondrogenic and hypertrophic genes. The results showed that growth medium with AA significantly enhanced the proliferation of cAMSCs without affecting cell viability and modulated the expression of chondrogenic and hypertrophic genes of cAMSCs grown on SF films. Our results suggest that AA may be used in growth medium for expansion of cAMSCs and, at the same time, provide the basis for future studies to investigate the role of AA and SF in chondrogenic differentiation of MSCs.

The matrix microenvironment influences but does not dominate tissue-specific stem cell lineage differentiation

Mesenchymal stem cells (MSCs) play a pivotal role in tissue engineering and regenerative medicine, with their clinical application often hindered by cell senescence during ex vivo expansion. Recent studies suggest that MSC-deposited decellularized extracellular matrix (dECM) offers a conducive microenvironment that fosters cell proliferation and accentuates stem cell differentiation. However, the ability of this matrix environment to govern lineage differentiation of tissue-specific stem cells remains ambiguous. This research employs human adipose-derived MSCs (ADSCs) and synovium-derived MSCs (SDSCs) as models for adipogenesis and chondrogenesis differentiation pathways, respectively. Genetically modified dECM (GMdECM), produced by SV40LT-transduced immortalized cells, was studied for its influence on cell differentiation. Both types of immortalized cells displayed a reduction in chondrogenic ability but an enhancement in adipogenic potential. ADSCs grown on ADSC-deposited dECM showed stable chondrogenic potential but increased adipogenic capacity; conversely, SDSCs expanded on SDSC-generated dECM displayed elevated chondrogenic capacity and diminished adipogenic potential. This cell-dependent response was confirmed through GMdECM expansion, with SDSCs showing enhanced chondrogenesis. However, ADSCs did not exhibit improved chondrogenic potential on GMdECM, suggesting that the matrix microenvironment does not dictate the final differentiation path of tissue-specific stem cells. Potential molecular mechanisms, such as elevated basement membrane protein expression in GMdECMs and dynamic TWIST1 expression during expansion and chondrogenic induction, may underpin the strong chondrogenic differentiation of GMdECM-expanded SDSCs.

Exosomes derived from bone marrow mesenchymal stem cells pretreated with decellularized extracellular matrix enhance the alleviation of osteoarthritis through miR-3473b/phosphatase and tensin homolog axis

BACKGROUND

Osteoarthritis (OA) is a prevalent degenerative articular disease for which there is no effective treatment. Progress has been made in mesenchymal stem cell (MSC)-based therapy in OA, and the efficacy has been demonstrated to be a result of paracrine exosomes from MSCs. Decellularized extracellular matrix (dECM) provides an optimum microenvironment for the expansion of MSCs. In the present study, we aimed to investigate whether exosomes isolated from bone marrow mesenchymal stem cells (BMSCs) with dECM pretreatment (dECM-BMSC-Exos) enhance the amelioration of OA.

METHODS

Exosomes from BMSCs with or without dECM pretreatment were isolated. We measured and compared the effect of the BMSC-Exo and dECM-BMSC-Exo on interleukin (IL)-1β-induced chondrocytes by analyzing proliferation, anabolism and catabolism, migration and apoptosis in vitro. The in vivo experiment was performed by articular injection of exosomes into DMM mice, followed by histological evaluation of cartilage. MicroRNA sequencing of exosomes was performed on BMSC-Exo and dECM-BMSC-Exo to investigate the underlying mechanism. The function of miR-3473b was validated by rescue studies in vitro and in vivo using antagomir-3473b.

RESULTS

IL-1β-treated chondrocytes treated with dECM-BMSC-Exos showed enhanced proliferation, anabolism, migration and anti-apoptosis properties compared to BMSC-Exos. DMM mice injected with dECM-BMSC-Exo showed better cartilage regeneration than those injected with BMSC-Exo. Interestingly, miR-3473b was significantly elevated in dECM-BMSC-Exos and was found to mediate the protective effect in chondrocytes by targeting phosphatase and tensin homolog (PTEN), which activated the PTEN/AKT signaling pathway.

CONCLUSIONS

dECM-BMSC-Exo can enhance the alleviation of osteoarthritis via promoting migration, improving anabolism and inhibiting apoptosis of chondrocytes by upregulating miR-3473b, which targets PTEN.

Toward defining the role of the synovium in mitigating normal articular cartilage wear and tear

Cartilage repair has been studied extensively in the context of injury and disease, but the joint's management of regular sub-injurious damage to cartilage, or 'wear and tear,' which occurs due to normal activity, is poorly understood. We hypothesize that this cartilage maintenance is mediated in part by cells derived from the synovium that migrate to the worn articular surface. Here, we demonstrate in vitro that the early steps required for such a process can occur. First, we show that under physiologic mechanical loads, chondrocyte death occurs in the cartilage superficial zone along with changes to the cartilage surface topography. Second, we show that synoviocytes are released from the synovial lining under physiologic loads and attach to worn cartilage. Third, we show that synoviocytes parachuted onto a simulated or native cartilage surface will modify their behavior. Specifically, we show that synoviocyte interactions with chondrocytes lead to changes in synoviocyte mechanosensitivity, and we demonstrate that cartilage-attached synoviocytes can express COL2A1, a hallmark of the chondrogenic phenotype. Our findings suggest that synoviocyte-mediated repair of cartilage 'wear and tear' as a component of joint homeostasis is feasible and is deserving of future study.

Matrix from urine stem cells boosts tissue-specific stem cell mediated functional cartilage reconstruction

Articular cartilage has a limited capacity to self-heal once damaged. Tissue-specific stem cells are a solution for cartilage regeneration; however, ex vivo expansion resulting in cell senescence remains a challenge as a large quantity of high-quality tissue-specific stem cells are needed for cartilage regeneration. Our previous report demonstrated that decellularized extracellular matrix (dECM) deposited by human synovium-derived stem cells (SDSCs), adipose-derived stem cells (ADSCs), urine-derived stem cells (UDSCs), or dermal fibroblasts (DFs) provided an ex vivo solution to rejuvenate human SDSCs in proliferation and chondrogenic potential, particularly for dECM deposited by UDSCs. To make the cell-derived dECM (C-dECM) approach applicable clinically, in this study, we evaluated ex vivo rejuvenation of rabbit infrapatellar fat pad-derived stem cells (IPFSCs), an easily accessible alternative for SDSCs, by the abovementioned C-dECMs, in vivo application for functional cartilage repair in a rabbit osteochondral defect model, and potential cellular and molecular mechanisms underlying this rejuvenation. We found that C-dECM rejuvenation promoted rabbit IPFSCs' cartilage engineering and functional regeneration in both ex vivo and in vivo models, particularly for the dECM deposited by UDSCs, which was further confirmed by proteomics data. RNA-Seq analysis indicated that both mesenchymal-epithelial transition (MET) and inflammation-mediated macrophage activation and polarization are potentially involved in the C-dECM-mediated promotion of IPFSCs' chondrogenic capacity, which needs further investigation.

Extracellular matrix derived from Wharton's Jelly-derived mesenchymal stem cells promotes angiogenesis via integrin αVβ3/c-Myc/P300/VEGF

BACKGROUND

Angiogenesis is required in many physiological conditions, including bone regeneration, wound healing, and tissue regeneration. Mesenchymal stem cells-derived extracellular matrix (MSCs-ECM) could guide intricate cellular and tissue processes such as homeostasis, healing and regeneration.

METHODS

The purpose of this study is to explore the effect and mechanism of ECM derived from decellularized Wharton's Jelly-derived mesenchymal stem cells (WJ-MSCs) on endothelial cell viability and angiogenesis. The human umbilical vein endothelial cells (HUVECs) were pretreated with WJ-MSCs ECM for 2d/7d/14d, respectively. After pretreatment, the angiogenesis ability of HUVECs was detected.

RESULTS

In this study, we found for the first time that WJ-MSCs ECM could improve the angiogenesis ability of HUVECs with a time-dependent manner in vitro. Mechanically, WJ-MSCs ECM activated the focal adhesion kinase (FAK)/P38 signaling pathway via integrin αVβ3, which further promoted the expression of the cellular (c)-Myc. Further, c-Myc increased histone acetylation levels of the vascular endothelial growth factor (VEGF) promoter by recruiting P300, which ultimately promoting VEGF expression.

CONCLUSIONS

ECM derived from Wharton's Jelly-derived mesenchymal stem cells promotes angiogenesis via integrin αVβ3/c-Myc/P300/VEGF. This study is expected to provide a new approach to promote angiogenesis in bone and tissue regeneration.

Stem cells immortalized by hTERT perform differently from those immortalized by SV40LT in proliferation, differentiation, and reconstruction of matrix microenvironment

Although matrix microenvironment has the potential to improve expanded stem cell proliferation and differentiation capacity, decellularized extracellular matrix (dECM) deposited by senescent cells does not contribute to the rejuvenation of adult stem cells, which has become a barrier to personalized stem cell therapy. Genetic modification is an effective strategy to protect cells from senescence but it carries the increased risk of malignant transformation and genetic instability. In this study, lentivirus carrying either human telomerase reverse transcriptase (hTERT) or simian virus 40 large T antigen (SV40LT) was used to transduce human infrapatellar fat pad-derived stem cells (IPFSCs). We found that virus transduction modified the proliferative, chondrogenic, and adipogenic abilities of IPFSCs. Interestingly, dECM deposited by immortalized cells significantly influenced replicative senescent IPFSCs in proliferation and differentiation preference, the effect of which is hinged on the approach of immortalization using either SV40LT or hTERT. Our findings indicate both dECM expansion and immortalization strategies can be used for replicative senescent adult stem cells' proliferation and lineage-specific differentiation, which benefits future stem cell-based tissue regeneration. This approach may also work for adult stem cells with premature senescence in elderly/aged patients, which needs further investigation. STATEMENT OF SIGNIFICANCE: Adult stem cells are a promising solution for autologous cell-based therapy. Unfortunately, cell senescence due to donor age and/or ex vivo expansion prevents clinical application. Recent progress with decellularized extracellular matrix provides a potential for the rejuvenation of senescent stem cells by improving their proliferation and differentiation capacities. Given the fact that the young matrix can provide a healthy and energetic microenvironment, in this study, two approaches using lentivirus transduction of hTERT and SV40LT were compared. The goal was to immortalize donor cells for deposition of decellularized extracellular matrix. The matrix was demonstrated to contribute diverging effects on the chondrogenic and adipogenic differentiation of expanded stem cells and exhibited proliferation benefits as well. These findings provide an invaluable asset for stem cell-based tissue regeneration.

Matrix reverses immortalization-mediated stem cell fate determination

Primary cell culture in vitro suffers from cellular senescence. We hypothesized that expansion on decellularized extracellular matrix (dECM) deposited by simian virus 40 large T antigen (SV40LT) transduced autologous infrapatellar fat pad stem cells (IPFSCs) could rejuvenate high-passage IPFSCs in both proliferation and chondrogenic differentiation. In the study, we found that SV40LT transduced IPFSCs exhibited increased proliferation and adipogenic potential but decreased chondrogenic potential. Expansion on dECMs deposited by passage 5 IPFSCs yielded IPFSCs with dramatically increased proliferation and chondrogenic differentiation capacity; however, this enhanced capacity diminished if IPFSCs were grown on dECM deposited by passage 15 IPFSCs. Interestingly, expansion on dECM deposited by SV40LT transduced IPFSCs yielded IPFSCs with enhanced proliferation and chondrogenic capacity but decreased adipogenic potential, particularly for the dECM group derived from SV40LT transduced passage 15 cells. Our immunofluorescence staining and proteomics data identify matrix components such as basement membrane proteins as top candidates for matrix mediated IPFSC rejuvenation. Both cell proliferation and differentiation were endorsed by transcripts measured by RNASeq during the process. This study provides a promising model for in-depth investigation of the matrix protein influence on surrounding stem cell differentiation.

Unfavorable Contribution of a Tissue-Engineering Cartilage Graft to Osteochondral Defect Repair in Young Rabbits

A stem cell-based tissue-engineering approach is a promising strategy for treatment of cartilage defects. However, there are conflicting data in the feasibility of using this approach in young recipients. A young rabbit model with an average age of 7.7 months old was used to evaluate the effect of a tissue-engineering approach on the treatment of osteochondral defects. Following in vitro evaluation of proliferation and chondrogenic capacity of infrapatellar fat pad-derived stem cells (IPFSCs) after expansion on either tissue culture plastic (TCP) or decellularized extracellular matrix (dECM), a premature tissue construct engineered from pretreated IPFSCs was used to repair osteochondral defects in young rabbits. We found that dECM expanded IPFSCs exhibited higher proliferation and chondrogenic differentiation compared to TCP expanded cells in both pellet and tissue construct culture systems. Six weeks after creation of bilateral osteochondral defects in the femoral trochlear groove of rabbits, the Empty group (left untreated) had the best cartilage resurfacing with the highest score in Modified O’Driscoll Scale (MODS) than the other groups; however, this score had no significant difference compared to that of 15-week samples, indicating that young rabbits stop growing cartilage once they reach 9 months old. Interestingly, implantation of premature tissue constructs from both dECM and TCP groups exhibited significantly improved cartilage repair at 15 weeks compared to those at six weeks (about 9 months old), indicating that a tissue-engineering approach is able to repair adult cartilage defects. We also found that implanted pre-labeled cells in premature tissue constructs were undetectable in resurfaced cartilage at both time points. This study suggests that young rabbits (less than 9 months old) might respond differently to the classical tissue-engineering approach that is considered as a potential treatment for cartilage defects in adult rabbits.

Cell-derived decellularized extracellular matrix scaffolds for articular cartilage repair

Articular cartilage repair remains a great clinical challenge. Tissue engineering approaches based on decellularized extracellular matrix (dECM) scaffolds show promise for facilitating articular cartilage repair. Traditional regenerative approaches currently used in clinical practice, such as microfracture, mosaicplasty, and autologous chondrocyte implantation, can improve cartilage repair and show therapeutic effect to some degree; however, the long-term curative effect is suboptimal. As dECM prepared by proper decellularization procedures is a biodegradable material, which provides space for regeneration tissue growth, possesses low immunogenicity, and retains most of its bioactive molecules that maintain tissue homeostasis and facilitate tissue repair, dECM scaffolds may provide a biomimetic microenvironment promoting cell attachment, proliferation, and chondrogenic differentiation. Currently, cell-derived dECM scaffolds have become a research hotspot in the field of cartilage tissue engineering, as ECM derived from cells cultured in vitro has many advantages compared with native cartilage ECM. This review describes cell types used to secrete ECM, methods of inducing cells to secrete cartilage-like ECM and decellularization methods to prepare cell-derived dECM. The potential mechanism of dECM scaffolds on cartilage repair, methods for improving the mechanical strength of cell-derived dECM scaffolds, and future perspectives on cell-derived dECM scaffolds are also discussed in this review.

Site-Dependent Lineage Preference of Adipose Stem Cells

Adult stem cells have unique properties in both proliferation and differentiation preference. In this study, we hypothesized that adipose stem cells have a depot-dependent lineage preference. Four rabbits were used to provide donor-matched adipose stem cells from either subcutaneous adipose tissue (ScAT) or infrapatellar fat pad (IPFP). Proliferation and multi-lineage differentiation were evaluated in adipose stem cells from donor-matched ScAT and IPFP. RNA sequencing (RNA-seq) and proteomics were conducted to uncover potential molecular discrepancy in adipose stem cells and their corresponding matrix microenvironments. We found that stem cells from ScAT exhibited significantly higher proliferation and adipogenic capacity compared to those from donor-matched IPFP while stem cells from IPFP displayed significantly higher chondrogenic potential compared to those from donor-matched ScAT. Our findings are strongly endorsed by supportive data from transcriptome and proteomics analyses, indicating a site-dependent lineage preference of adipose stem cells.

Role of lineage-specific matrix in stem cell chondrogenesis

Cartilage repair in clinics is a challenge owing to the limited regenerative capacities of cartilage. Synovium-derived stem cells (SDSCs) are suggested as tissue-specific stem cells for chondrogenesis. In this study, we hypothesize that decellularized extracellular matrix (dECM) deposited by SDSCs could provide a superior tissue-specific matrix microenvironment for optimal rejuvenation of adult SDSCs for cartilage regeneration. dECMs were deposited by adult stem cells with varying chondrogenic capacities; SDSCs (strong) (SECM), adipose-derived stem cells (weak) (AECM) and dermal fibroblasts (weak) (DECM), and urine-derived stem cells (none) (UECM). Plastic flasks (Plastic) were used as a control substrate. Human SDSCs were expanded on the above substrates for one passage and examined for chondrogenic capacities. We found that each dECM consisted of unique matrix proteins and exhibited varied stiffnesses, which affected cell morphology and elasticity. Human SDSCs grown on dECMs displayed a significant increase in cell proliferation and unique surface phenotypes. Under induction media, dECM expanded cells yielded pellets with a dramatically increased number of chondrogenic markers. Interestingly, SECM expanded cells had less potential for hypertrophy compared to those grown on other dECMs, indicating that a tissue-specific matrix might provide a superior microenvironment for stem cell chondrogenic differentiation.

Impact of Fibronectin Knockout on Proliferation and Differentiation of Human Infrapatellar Fat Pad-Derived Stem Cells

Fibronectin plays an essential role in tissue development and regeneration. However, the effects of fibronectin knockout (FN1-KO) on stem cells' proliferation and differentiation remain unknown. In this study, CRISPR/Cas9 generated FN1-KO in human infrapatellar fat pad-derived stem cells (IPFSCs) was evaluated for proliferation ability including cell cycle and surface markers as well as stemness gene expression and for differentiation capacity including chondrogenic and adipogenic differentiation. High passage IPFSCs were also evaluated for proliferation and differentiation capacity after expansion on decellularized ECM (dECM) deposited by FN1-KO cells. Successful FN1-KO in IPFSCs was confirmed by Sanger sequencing and Inference of CRISPR Edits analysis (ICE) as well as immunostaining for fibronectin expression. Compared to the GFP control, FN1-KO cells showed an increase in cell growth, percentage of cells in the S and G2 phases, and CD105 and CD146 expression but a decrease in expression of stemness markers CD73, CD90, SSEA4, and mesenchymal condensation marker CDH2 gene. FN1-KO decreased both chondrogenic and adipogenic differentiation capacity. Interestingly, IPFSCs grown on dECMs deposited by FN1-KO cells exhibited a decrease in cell proliferation along with a decline in CDH2 expression. After induction, IPFSCs plated on dECMs deposited by FN1-KO cells also displayed decreased expression of both chondrogenic and adipogenic capacity. We concluded that FN1-KO increased human IPFSCs' proliferation capacity; however, this capacity was reversed after expansion on dECM deposited by FN1-KO cells. Significance of fibronectin in chondrogenic and adipogenic differentiation was demonstrated in both FN1-KO IPFSCs and FN(-) matrix microenvironment.

Functionality of decellularized matrix in cartilage regeneration: A comparison of tissue versus cell sources

Increasing evidence indicates that decellularized extracellular matrices (dECMs) derived from cartilage tissues (T-dECMs) or chondrocytes/stem cells (C-dECMs) can support proliferation and chondrogenic differentiation of cartilage-forming cells. However, few review papers compare the differences between these dECMs when they serve as substrates for cartilage regeneration. In this review, after an introduction of cartilage immunogenicity and decellularization methods to prepare T-dECMs and C-dECMs, a comprehensive comparison focuses on the effects of T-dECMs and C-dECMs on proliferation and chondrogenic differentiation of chondrocytes/stem cells in vitro and in vivo. Key factors within dECMs, consisting of microarchitecture characteristics and micromechanical properties as well as retained insoluble and soluble matrix components, are discussed in-depth for potential mechanisms underlying the functionality of these dECMs in regulating chondrogenesis. With this information, we hope to benefit dECM based cartilage engineering and tissue regeneration for future clinical application.

STATEMENT OF SIGNIFICANCE

The use of decellularized extracellular matrix (dECM) is becoming a promising approach for tissue engineering and regeneration. Compared to dECM derived from cartilage tissue, recently reported dECM from cell sources exhibits a distinct role in cell based cartilage regeneration. In this review paper, for the first time, tissue and cell based dECMs are comprehensively compared for their functionality in cartilage regeneration. This information is expected to provide an update for dECM based cartilage regeneration.