Targeting Mechanics-Induced Fibroblast Activation through CD44-RhoA-YAP Pathway Ameliorates Crystalline Silica-Induced Silicosis.

Abstract

Silicosis is pneumoconiosis of the lung, usually resulting from prolonged exposure to crystalline silica (CS). The hallmark of silicosis is excessive extracellular matrix (ECM) deposition produced by activated fibroblasts. Recent work demonstrated that excessive ECM-forming mechanical cues play an essential role in promoting fibroblast activation and perpetuating fibrotic pathologies. However, the detailed molecular mechanism still needs to be uncovered. Methods: NIH-3T3 fibroblasts were cultured on either 1 kappa (soft) or 60 kappa (stiff) gel-coated coverslips. A series of knockdown and reverse experiments in vitro were performed to establish the signaling for mechanics-induced fibroblast activation. An experimental model of silicosis was established by one-time intratracheal instillation of CS suspension. The cluster of differentiation 44 (CD44) antibody (IM7), dihydrotanshinone I (DHI) and verteporfin (VP) were used to explore the effect of CD44-RhoA-YAP signaling blockade on mechanics-induced fibroblast activation and CS-induced pulmonary fibrosis. Results: Matrix stiffness could induce nuclear translocation of the Yes-associated protein (YAP) through CD44 in fibroblasts. This effect required RhoA activity and F-actin cytoskeleton polymerization but was independent of Hippo pathway kinases, Mst 1 and Lats 1, forming CD44-RhoA-YAP signaling pathway. Pharmacological upstream blocking by CD44 antibody or downstream blockade of YAP by DHI or VP could attenuate fibroblast migration, invasion, proliferation, and collagen deposition. Furthermore, CD44-RhoA-YAP signaling blockade could alleviate CS-induced fibrosis and improve pulmonary function in vivo. Conclusion: CD44-RhoA-YAP signaling mediates mechanics-induced fibroblast activation. Targeting this pathway could ameliorate crystalline silica-induced silicosis and provide a potential therapeutic strategy to mitigate fibrosis.

• Authors: Siyi Li, Chao Li, Yiting Zhang, Xiu He, Xi Chen, Xinning Zeng, Fangwei Liu, Ying Chen, Jie Chen
• Journal: Theranostics (Theranostics) Vol. 9 Issue 17 Pg. 4993-5008 ( 2019) ISSN: 1838-7640 [Electronic] Australia
• PMID: 31410197 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Actins
• Adaptor Proteins, Signal Transducing
• Antibodies
• Cell Cycle Proteins
• Furans
• Hyaluronan Receptors
• Phenanthrenes
• Proto-Oncogene Proteins
• Quinones
• YAP-Signaling Proteins
• Yap1 protein, mouse
• macrophage stimulating protein
• Verteporfin
• dihydrotanshinone I
• Hepatocyte Growth Factor
• Silicon Dioxide
• Lats1 protein, mouse
• Protein Serine-Threonine Kinases
• RhoA protein, mouse
• rhoA GTP-Binding Protein

Topics

• 3T3 Cells
• Actins (metabolism)
• Adaptor Proteins, Signal Transducing (antagonists & inhibitors, metabolism)
• Animals
• Antibodies (immunology, therapeutic use)
• Cell Cycle Proteins (antagonists & inhibitors, metabolism)
• Cell Movement
• Cell Proliferation
• Extracellular Matrix (drug effects, metabolism)
• Fibroblasts (drug effects, metabolism, physiology)
• Furans
• Hepatocyte Growth Factor (metabolism)
• Hyaluronan Receptors (immunology, metabolism)
• Male
• Mice
• Mice, Inbred C57BL
• Phenanthrenes (pharmacology, therapeutic use)
• Protein Serine-Threonine Kinases (metabolism)
• Proto-Oncogene Proteins (metabolism)
• Quinones
• Signal Transduction
• Silicon Dioxide (toxicity)
• Silicosis (drug therapy, metabolism)
• Verteporfin (pharmacology, therapeutic use)
• YAP-Signaling Proteins
• rhoA GTP-Binding Protein (metabolism)