Altered TGF-β endocytic trafficking contributes to the increased signaling in Marfan syndrome

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1864

Article

Siegert, Anna-Maria¹  Serra-Peinado, Carla¹  Gutierrez-Martinez, Enric¹  Rodriguez-Pascual, Fernando²  Fabregat, Isabel³  Egea, Gustavo^1,4,5 

[1] Univ Barcelona, Dept Biomed, Fac Med & Ciencias Salud, C Casanova 143, E-08036 Barcelona, Catalonia, Spain

[2] UAM, CSIC, Ctr Biol Mol Severo Ochoa, Madrid 28049, Spain

[3] Inst Invest Biomed Bellvitge IDIBELL, Barcelona 08908, Catalonia, Spain

[4] IDIBAPS, Barcelona 08036, Catalonia, Spain

[5] Univ Barcelona, Inst Nanociencia & Nanotecnol IN2UB, Barcelona, Catalonia, Spain

关键词: Marfan syndrome;    Human vascular smooth muscle cells;    Membrane trafficking;    TGF-beta signaling;    Endocytosis;   

DOI  :  10.1016/j.bbadis.2017.11.015

来源: Elsevier

【 摘 要 】

The main cardiovascular alteration in Marfan syndrome (MFS) is the formation of aortic aneurysms in which augmented TGF-beta signaling is reported. However, the primary role of TGF-beta signaling as a molecular link between the genetic mutation of fibrillin-1 and disease onset is controversial. The compartmentalization of TGF-beta endocytic trafficking has been shown to determine a signaling response in which clathrin-dependent internalization leads to TGF-beta signal propagation, and caveolin-1 (CAV-1) associated intemalization leads to signal abrogation. We here studied the contribution of endocytic trafficking compartmentalization to increased TGF-beta signaling in vascular smooth muscle cells (VSMC) from MFS patients. We examined molecular components involved in clathrin-(SARA, SMAD2) and caveolin-1-(SMAD7, SMURF2) dependent endocytosis. Marfan VSMC showed higher recruitment of SARA and SMAD2 to membranes and their increased interaction with TGF-beta receptor II, as well as higher colocalization of SARA with the early endosome marker EEA1. We assessed TGF-beta internalization using a biotinylated ligand (b-TGF-beta), which colocalized equally with either EEA1 or CAVA in VSMC from Marfan patients and controls. However, in Marfan cells, colocalization of b-TGF-beta with SARA and EEA1 was increased and accompanied by decreased colocalization with CAV-1 at EEA1-positive endosomes. Moreover, Marfan VSMC showed higher transcriptional levels and membrane enrichment of RAB5. Our results indicate that increased RAB5-associated SARA localization to early endosomes facilitates its TGF-beta receptor binding and phosphorylation of signaling mediator SMAD2 in Marfan VSMC. This is accompanied by a reduction of TGF-beta sorting into multifunctional vesicles containing cargo from both internalization pathways.

【 授权许可】

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