The actin cytoskeleton of hepatic stellate cells (HSCs) is reorganized when they are cultured in 3D collagen matrices. Here, we investigated the molecular mechanism of actin cytoskeleton reorganization in HSCs cultured in 3D floating collagen matrices (FCM) compared to those on 2D polystyrene surfaces (PS). First, we found that the generation of dendritic cellular processes was controlled by Rac1. Next, we examined the differential gene expression of HSCs cultured on 2D PS and in 3D FCM by RNA-Seq and focused on the changes of actin cytoskeleton reorganization-related molecular components and guanine nucleotide exchange factors (GEFs). The results showed that the expression of genes associated with actin cytoskeleton reorganization-related cellular components, filopodia and lamellipodia, were significantly decreased, but podosome-related genes was significantly increased in 3D FCM. Furthermore, we found that a Rac1-specific GEF, ARHGEF4, played roles in morphological changes, migration and podosome-related gene expression in HSCs cultured in 3D FCM. Abbreviations: 2D PS: 2-dimensional polystyrene surface; 3D FCM: 3-dimensional floating collagen matrices; ARHGEF4: Rho guanine nucleotide exchange factor 4; ARHGEF6: Rho guanine nucleotide exchange factor 6; GEF: guanine nucleotide exchange factor; HSC: hepatic stellate cell.

中文翻译：

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ARHGEF4介导3维胶原蛋白基质中肝星状细胞的肌动蛋白细胞骨架重组。

在3D胶原蛋白基质中培养肝星状细胞（HSC）的肌动蛋白细胞骨架。在这里，我们研究了在2D聚苯乙烯表面（PS）上培养的3D浮动胶原蛋白基质（FCM）中培养的HSC中肌动蛋白细胞骨架重组的分子机制。首先，我们发现树突状细胞过程的生成受Rac1控制。接下来，我们检查了通过RNA-Seq在2D PS和3D FCM中培养的HSC的差异基因表达，并重点研究了肌动蛋白细胞骨架重组相关分子成分和鸟嘌呤核苷酸交换因子（GEF）的变化。结果表明，与肌动蛋白细胞骨架重组相关的细胞成分，丝状伪足和片状脂质体相关的基因的表达显着降低，但在3D FCM中，足小体相关基因显着增加。此外，我们发现Rac1特异性GEF ARHGEF4在3D FCM中培养的HSC中在形态变化，迁移和足小体相关基因表达中起作用。缩写：2D PS：二维聚苯乙烯表面；3D FCM：3维浮动胶原蛋白矩阵；ARHGEF4：Rho鸟嘌呤核苷酸交换因子4；ARHGEF6：Rho鸟嘌呤核苷酸交换因子6；GEF：鸟嘌呤核苷酸交换因子；HSC：肝星状细胞。Rho鸟嘌呤核苷酸交换因子4; ARHGEF6：Rho鸟嘌呤核苷酸交换因子6；GEF：鸟嘌呤核苷酸交换因子；HSC：肝星状细胞。Rho鸟嘌呤核苷酸交换因子4; ARHGEF6：Rho鸟嘌呤核苷酸交换因子6；GEF：鸟嘌呤核苷酸交换因子；HSC：肝星状细胞。