慢性肺移植拒絶に新たな手がかり(Chronic lung-transplant rejection has been a black box: new study gives answers and drug targets)

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2025-10-22 ノースウェスタン大学

ノースウェスタン大学医学部の研究チームは、慢性肺移植拒絶(CLAD)の細胞・分子メカニズムを世界で初めて詳細に解明した。肺移植後5年以内に約半数の患者が拒絶反応を起こすが、これまで原因は不明だった。研究者らは160万個以上の細胞を解析し、ドナー由来の構造細胞と受容者の免疫細胞が異常な「会話」を交わし、炎症と線維化を進行させることを発見。また、肺線維症やCOPD、COVID-19後遺症など他の肺疾患にも共通する新たな細胞型(KRT17/KRT5細胞)を特定した。解析の結果、PDGF、GDF15、TWEAKなどのシグナル経路が病態を駆動しており、既存薬ピルフェニドン(Esbriet)やニンテダニブ(Ofev)の再利用も有望とされる。これらの知見は移植医療だけでなく、あらゆる肺線維症治療への応用が期待され、「肺瘢痕化のロゼッタストーン」と呼ばれる基礎資料を提供した。研究成果は『JCI Insight』誌に掲載された。

<関連情報>

慢性肺移植機能不全の単一細胞解剖により、収束的かつ明確な線維化メカニズムが明らかになった Single-cell dissection of chronic lung allograft dysfunction reveals convergent and distinct fibrotic mechanisms

Yuanqing Yan, Taisuke Kaihou, Emilia Lecuona, Xin Wu, Masahiko Shigemura, Haiying Sun, Chitaru Kurihara, Ruli Gao, Felix L. Nunez-Santana, G.R. Scott Budinger, and Ankit Bharat
JCI Insight  Published: October 22, 2025
DOI:https://doi.org/10.1172/jci.insight.197579

慢性肺移植拒絶に新たな手がかり(Chronic lung-transplant rejection has been a black box: new study gives answers and drug targets)

Abstract

Chronic lung allograft dysfunction (CLAD) is the leading cause of mortality after lung transplantation, yet its molecular mechanisms remain poorly understood. To elucidate the pathogenesis of CLAD, we conducted a comprehensive single-cell transcriptomic analysis of CLAD lungs, integrating our generated datasets with approximately 1.6 million cells from 15 published studies of other fibrotic lung diseases. By applying pseudo-bulk approaches to mitigate batch effects, we identified molecular signatures specific to CLAD and those shared with idiopathic pulmonary fibrosis, COVID-19, and other fibrotic conditions. Our analysis revealed CLAD-specific cellular subsets including Fibro.AT2 cells, exhausted CD8+ T cells, and superactivated macrophages while suggesting that pathogenic keratin 17–positive, keratin 5–negative (KRT17+KRT5) cells represent a common fibrotic mechanism across fibrotic lung diseases. Additionally, we performed donor-recipient cell deconvolution in lung allografts, uncovering distinct transcriptional programs and intercellular crosstalk between donor- and recipient-derived cells that drive allograft fibrosis. Recipient-derived stromal and immune cells showed enhanced pro-fibrotic and allograft rejection pathways compared with their donor counterparts. By leveraging insights from other fibrotic diseases to elucidate CLAD-specific mechanisms, our study provides a molecular framework for understanding CLAD pathogenesis and identifies potential therapeutic targets for this treatment-refractory condition.

医療・健康
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