Biology subjects

Aszodi, A.

Publications and source records attributed to Aszodi, A..

3 recordsLinked to original sources

bioRxiv2026

Aggrecan hypomorphism accelerates the progression of post-traumatic osteoarthritis in mice

ObjectiveThe Agc1CreERT2 mouse line is a powerful tamoxifen-inducible genetic tool used for conditional gene manipulation specifically in cartilage. The aim of this study was to investigate the effects of aggrecan hypomorphism on the progression of post-traumatic osteoarthritis (PT-OA) in Agc1CreERT2 mice. MethodsProteoglycan content in cartilage samples from the knees of E18.5 embryos were quantified by sulfated glycosaminoglycan (sGAG) assay. Destabilization of the medial meniscus (DMM) surgery was performed to induce PT-OA in 12-week-old wild-type, heterozygous Agc1CreERT2/+ and homozygous Agc1CreERT2/CreERT2 mice. Progression of OA was assessed at 4-, 8-, and 12-weeks post-DMM by OARSI, synovitis and osteophyte maturation histopathology scores and micro-computed tomography ({micro}CT). Aggrecan deposition, cartilage matrix-degrading proteases, aggrecan and collagen II degradation neoepitopes were investigated by immunohistochemical staining, and serum C-terminal cross-linked telopeptide of type II collagen (CTX-II) levels by an enzyme-linked immunosorbent assay (ELISA). Chondrocyte apoptosis was analyzed with the terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay. The biomechanical properties of articular cartilage (AC) were investigated with indentation-type atomic force microscopy (IT-AFM). ResultsBefore DMM, homozygous Agc1CreERT2/CreERT2 mice had reduced sGAG and aggrecan levels and increased cartilage stiffness. After DMM, they exhibited increased cartilage degradation, synovitis, osteophyte formation and meniscus mineralization, chondrocyte apoptosis and cartilage stiffness compared with wild-type mice. Immunohistochemistry demonstrated increased expression of the aggrecanase ADAMTS-5, the metalloproteinase MMP-13, the aggrecan degradation neoepitope NITEGE and the collagen degradation neoepitope C1,2C in AC. ELISA also revealed elevated serum CTX-II levels. Heterozygous Agc1CreERT2/+ mice also exhibited accelerated PT-OA compared with wild-type mice, characterized by elevated CTX-II levels at 4-weeks, increased synovitis, osteophyte and soft tissue mineralization at 8-weeks, and more severe cartilage degeneration at 12-weeks post-DMM. ConclusionBoth homozygous and heterozygous Agc1CreERT2mice exhibit increased susceptibility to PT-OA, underscoring the importance of physiological aggrecan expression in maintaining joint homeostasis and regulating joint pathophysiology. These findings indicate that Agc1CreERT2/+mice are not phenotypically neutral in the DMM model and that this intrinsic susceptibility should be considered when interpreting studies employing inducible, cartilage-specific gene deletion.

molecular biology↗

bioRxiv2026

Integrin α10β1- selected mesenchymal stem cells are protective in a murine model of post-traumatic osteoarthritis

BackgroundPost-traumatic osteoarthritis (PT-OA) is a debilitating condition with significant unmet clinical need. Mesenchymal stem cells (MSCs) represent promising candidates for the treatment of cartilage conditions, owing to their immunomodulatory and regenerative capacities. However, the marked heterogeneity of MSC preparations remains a major challenge for product standardization and prediction of therapeutic efficacy. We previously identified integrin 10{beta}1 as a marker for the selection of a more homogenous MSC preparation, with cartilage repair potential in vivo. In this study, we evaluated the therapeutic efficacy of human MSCs selected for high integrin 10{beta}1 expression in a murine PT-OA model, and compared their effects with those of unselected MSCs. MethodsUnselected or integrin 10-selected human bone marrow MSCs were characterized by flow cytometry and differentiation potential into adipogenic, osteogenic and chondrogenic lineages. Cells encapsulated into fibrin gel were applied intra-articularly at the time of surgery in the destabilization of the medial meniscus (DMM) mouse model of PT-OA. Eight weeks after DMM induction, severity of cartilage damage was assessed on Safranin O-stained sections using the OARSI scoring system. Synovitis, periarticular chondrogenesis, and osteophyte formation were evaluated histologically. OA-associated proteases, extracellular matrix degradation markers, and apoptosis were analyzed by immunohistochemistry, ELISA, and TUNEL assay. Persistence of transplanted human cells was assessed by PCR. ResultsIntegrin 10{beta}1-selected MSCs showed the characteristic MSCs immunophenotype and trilineage differentiation capacity. In vivo, treatment with integrin 10-selected MSCs significantly attenuated PT-OA-induced articular cartilage degeneration compared with both unselected MSCs and vehicle-treated controls. Further histopathological analyses revealed tendency toward reduced synovitis and periarticular chondrogenesis. Moreover, integrin 10-selected MSC treatment was associated with modest reductions in apoptotic activity and decreased expression of OA-related proteases and extracellular matrix degradation markers. Lastly, human cells were not detectable in joint tissues at the study endpoint. ConclusionsIntegrin 10-selected MSCs demonstrated superior chondroprotective effects compared with unselected MSCs, highlighting their potential as a standardized and efficacious cell therapy for PT-OA. These findings further validate the feasibility and safety of selection and in vivo administration of MSCs with high expression of integrin 10.

molecular biology↗

bioRxiv2024

Load activated FGFR and beta1 integrins target distinct chondrocyte mechano-response genes

In response to mechanical stimuli, chondrocytes adapt their transcriptional activity, thereby shaping the cellular mechano-response; however, it remains unclear whether the activation of cell surface receptors during mechanical loading converge in the activation of the same mechano-response genes, or whether pathway-specific genes can be defined. We aimed to determine whether load-activated FGF/FGFR signalling and {beta}1 integrin jointly activate ERK and control the same or distinct subsets of mechano-regulated genes. To this end, tissue-engineered neocartilage was generated from murine costal chondrocytes or human articular chondrocytes and subjected to dynamic unconfined compression with or without FGFR inhibition. To assess the role of {beta}1 integrins, neocartilage was generated from embryonic {beta}1 integrin-deficient or wild type costal chondrocytes. Load-activated FGFR signalling drove ERK activation in murine chondrocytes, and partially also in human chondrocytes, and mechano-response genes could be classified according to their regulation: Fosl1, Itga5, Ngf and Timp1 were regulated by load-activated FGFR depending on the developmental stage, whereas {beta}1 integrins controlled Inhba expression. In human chondrocytes, load-activated FGFR controlled expression of BMP2, PTGS2 and DUSP5, but not FOSB. We show here that the chondrocyte loading response is coordinated by concurrent activation of multiple receptors, and identified for the first time distinct target genes of activated receptors. These insights open up the opportunity to pharmacologically shape the mechano-response of chondrocytes in future studies with promising implications for the management of osteoarthritis and the development of novel therapeutic strategies.

cell biology↗