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Inhibition of KLF5-Myo9b-RhoA Pathway-Mediated Podosome Formation in Macrophages Ameliorates Abdominal Aortic Aneurysm

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posted on 2019-01-17, 15:08 authored by Dong Ma, Bin Zheng, Toru Suzuki, Ruonan Zhang, Chunyang Jiang, Disi Bai, Weina Yin, Zhan Yang, Xinhua Zhang, Lianguo Hou, Hong Zhan, Jin-kun Wen
RATIONALE: Abdominal aortic aneurysms (AAAs) are characterized by pathological remodeling of the aortic wall. Although both increased Krüppel-like factor 5 (KLF5) expression and macrophage infiltration have been implicated in vascular remodeling, the role of KLF5 in macrophage infiltration and AAA formation remains unclear. OBJECTIVE: To determine the role of KLF5 in AAA formation and macrophage infiltration into AAAs. METHODS AND RESULTS: KLF5 expression was significantly increased in human AAA tissues and in 2 mouse models of experimental AAA. Moreover, in myeloid-specific Klf5 knockout mice (myeKlf5-/- mice), macrophage infiltration, medial smooth muscle cell loss, elastin degradation, and AAA formation were markedly decreased. In cell migration and time-lapse imaging analyses, the migration of murine myeKlf5-/- macrophages was impaired, and in luciferase reporter assays, KLF5 activated Myo9b (myosin IXB) transcription by direct binding to the Myo9b promoter. In subsequent coimmunostaining studies, Myo9b was colocalized with filamentous actin, cortactin, vinculin, and Tks5 in the podosomes of phorbol 12,13-dibutyrate-treated macrophages, indicating that Myo9b participates in podosome formation. Gain- and loss-of-function experiments showed that KLF5 promoted podosome formation in macrophages by upregulating Myo9b expression. Furthermore, RhoA-GTP levels increased after KLF5 knockdown in macrophages, suggesting that KLF5 lies upstream of RhoA signaling. Finally, Myo9b expression was increased in human AAA tissues, located in macrophages, and positively correlated with AAA size. CONCLUSIONS: These data are the first to indicate that KLF5-dependent regulation of Myo9b/RhoA is required for podosome formation and macrophage migration during AAA formation, warranting consideration of the KLF5-Myo9b-RhoA pathway as a therapeutic target for AAA treatment.

Funding

This work is supported by the National Natural Science Foundation of China (No. 31671182, 31271396, 31271224, and 31301136) and the National Basic Research Program of China (No. 2012CB518601).

History

Citation

Circulation Research, 2017, 120 (5), pp. 799-815

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

  • AM (Accepted Manuscript)

Published in

Circulation Research

Publisher

American Heart Association, Lippincott, Williams & Wilkins

issn

0009-7330

eissn

1524-4571

Acceptance date

2017-01-23

Copyright date

2017

Available date

2019-01-17

Publisher version

https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.116.310367

Notes

The online-only Data Supplement is available with this article at http://circres.ahajournals.org/lookup/suppl/doi:10.1161/CIRCRESAHA.116.310367/-/DC1.

Language

en