肝臓の「硬さ」が肝線維化を促す仕組みの一端を解明ー肝星細胞の活性化初期に、肝再生と肝線維化への分岐を決めるー

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2026-09-29 東京科学大学

東京科学大学(Science Tokyo)の研究チームは、肝臓の「硬さ」が肝星細胞の状態を変化させ、肝線維化を促進する仕組みの一端を明らかにした。研究では、正常肝から肝硬変までを想定した異なる硬さの環境でマウス肝星細胞を培養し、単一細胞RNAシークエンスとトラジェクトリー解析を実施した。その結果、活性化初期の肝星細胞は、柔らかい環境では肝再生に関連する状態へ、硬い環境では肝線維化に関連する状態へ異なる軌道をたどることが判明した。さらに、硬い環境で特徴的に発現する「HSC Early Hard Signature」を同定し、この遺伝子群がヒト肝硬変組織でも高発現し、慢性肝疾患患者の重症化リスクと関連することを示した。肝線維化によって肝臓が硬くなり、その硬さがさらに線維化を促すという悪循環の一端を示す成果であり、肝硬変の進行予測や新たな治療法の開発につながることが期待される。

肝臓の「硬さ」が肝線維化を促す仕組みの一端を解明ー肝星細胞の活性化初期に、肝再生と肝線維化への分岐を決めるー
図1. 肝星細胞の活性化初期における硬さ別の形態変化。柔らかい環境では、肝星細胞の活性化初期の形態変化が抑えられている。

<関連情報>

細胞外マトリックスの硬さが肝星細胞活性化における初期の転写経路を形成する Matrix stiffness shapes early transcriptional trajectories during hepatic stellate cell activation

Kento Inada, Masato Miyoshi, Sei Kakinuma, Keiya Watakabe, Tomohiro Mochida, Taro Shimizu, Jun Tsuchiya, Tsubasa Nobusawa, Shun Kaneko, Fukiko Kawai-Kitahata, Miyako Murakawa, Sayuri Nitta, Mina Nakagawa, Yasuhiro Asahina & Ryuichi Okamoto
Hepatology International  Published:01 September 2026
DOI:https://doi.org/10.1007/s12072-026-11141-0

Abstract

Background
Matrix stiffness increases during fibrosis and drives hepatic stellate cell (HSC) activation through YAP-dependent mechanotransduction. Although recent studies have revealed HSC heterogeneity beyond classical quiescent and fully activated states, how physiological-range stiffness influences activation trajectories underlying this heterogeneity remains unclear. This study aimed to determine how substrate stiffness shapes the transcriptomic profiles and biases activation trajectories.

Methods
We performed time-resolved single-cell RNA sequencing of primary mouse HSCs cultured on stiffness-tunable polydimethylsiloxane (PDMS) substrates (Soft, 0.2 kPa; Hard, 32 kPa), using tissue culture polystyrene (TCPS) as a conventional baseline. In vitro findings were anchored to public in vivo datasets from mouse and human liver injury.

Results
Matrix stiffness altered HSC morphology and transcriptional state, with softer substrates promoting a rounder phenotype and reducing the expression of activation markers, particularly during early activation. Pseudotime and RNA velocity analyses also revealed different early trajectories associated with matrix stiffness. Under the soft condition, HSCs exhibited an expanded quiescent-to-initiatory transitional state characterized by Nrf2-related features and regeneration-associated factors, including Hgf and Rspo3. In contrast, the hard condition induced a gene signature, which was upregulated from early stages of HSC activation onward, localized to fibrotic septa in human liver and correlated with cirrhosis severity in an HCV patient cohort.

Conclusion
Matrix stiffness shapes early HSC activation trajectories toward transcriptional programs associated with regeneration or fibrosis. These findings support stiffness-controlled culture systems as improved models of HSC activation and provide a framework for regenerative and antifibrotic strategies.

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