Palmer Daniel R, Nims Robert, Zhang Bo, Guilak Farshid
Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, USA.
Shriners Hospitals for Children-Saint Louis, St. Louis, MO, USA.
Connect Tissue Res. 2025 May 21:1-24. doi: 10.1080/03008207.2025.2498512.
Chondrocytes, the only native cell type in cartilage, use mechanosensitive ion channels such as Transient Receptor Potential Vanilloid 4 (TRPV4) and PIEZO1 to transduce mechanical forces into transcriptomic changes that regulate cell behavior under both physiologic and pathologic conditions. Recent work has identified and characterized the differentially expressed genes (DEGs) that are upregulated following TRPV4 or PIEZO1 activation, but the transcriptomic systems downregulated by these ion channels also represent an important aspect of the chondrocyte regulatory process that remains poorly studied.
Here, we utilized previously established bulk RNAsequencing libraries to analyze the transcriptomes downregulated by activation of TRPV4 and PIEZO1 through differential gene expression analysis (using DESeq2), Gene Ontology, RT-qPCR, and Weighted Gene Correlation Network Analysis (WGCNA).
TRPV4 and PIEZO1 activations downregulated largely unique sets of DEGs, though the set of DEGs downregulated by TRPV4 exhibited a notable overlap with genes downregulated by treatment with inflammatory mediator Interleukin-1 (IL-1). The DEG set downregulated by PIEZO1 activation included genes associated with the G2/M cell cycle checkpoint, a system that checks cells for DNA damage prior to entry into mitosis, and this result was confirmed with RT-qPCR. WGCNA revealed modules of gene regulation negatively correlated with TRPV4, PIEZO1, and IL-1, outlining how these downregulated DEGs may interact to form gene regulatory networks (GRNs).
This study complements previous work in describing the full mechanosensitive transcriptome (or "mechanome") of differential gene expression in response to activation of mechanosensitive ion channels TRPV4 and PIEZO1 Q2 and suggests potential avenues for future therapeutic treatment design.
软骨细胞是软骨中唯一的天然细胞类型，它利用机械敏感离子通道，如瞬时受体电位香草酸受体4（TRPV4）和压电蛋白1（PIEZO1），将机械力转化为转录组变化，从而在生理和病理条件下调节细胞行为。最近的研究已经鉴定并表征了TRPV4或PIEZO1激活后上调的差异表达基因（DEG），但这些离子通道下调的转录组系统也是软骨细胞调节过程的一个重要方面，目前仍研究不足。
在这里，我们利用先前建立的大量RNA测序文库，通过差异基因表达分析（使用DESeq2）、基因本体论、RT-qPCR和加权基因共表达网络分析（WGCNA）来分析TRPV4和PIEZO1激活下调的转录组。
TRPV4和PIEZO1激活在很大程度上下调了独特的DEG集，尽管TRPV4下调的DEG集与炎症介质白细胞介素-1（IL-1）处理下调的基因有明显重叠。PIEZO1激活下调的DEG集包括与G2/M细胞周期检查点相关的基因，该系统在细胞进入有丝分裂之前检查DNA损伤，这一结果通过RT-qPCR得到证实。WGCNA揭示了与TRPV4、PIEZO1和IL-1负相关的基因调控模块，概述了这些下调的DEG如何相互作用形成基因调控网络（GRN）。
本研究补充了之前关于描述响应机械敏感离子通道TRPV4和PIEZO1激活的差异基因表达的完整机械敏感转录组（或“机械组”）的工作，并为未来治疗设计提出了潜在途径。
