RhoA regulates Activin B-induced stress fiber formation and migration of bone marrow-derived mesenchymal stromal cell through distinct signaling.
In our previous study, Activin B induced actin stress fiber formation and cell migration in Bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. However, the underlying molecular mechanisms are not well studied. RhoA is recognized to play a critical role in the regulation of actomyosin cytoskeletal organization and cell migration.



Pull-down assay was performed to investigate the activity of RhoA. The dominant-negative mutants of RhoA (RhoA(N19)) was used to determine whether RhoA has a role in Activin B-induced cytoskeleton organization and cell migration in BMSCs. Cytoskeleton organization was examined by fluorescence Rhodamine-phalloidin staining, and cell migration by transwell and cell scratching assay. Western blot was carried out to investigate downstream signaling cascade of RhoA. Inhibitor and siRNAs were used to detect the role of downstream signaling in stress fiber formation and/or cell migration.



RhoA was activated by Activin B in BMSCs. RhoA(N19) blocked Activin B-induced stress fiber formation and cell migration. ROCK inhibitor blocked Activin B-induced stress fiber formation but enhanced BMSCs migration. Activin B induced phosphorylation of LIMK2 and Cofilin, which was abolished by ROCK inhibition. Both of siRNA LIMK2 and siRNA Cofilin inhibited Activin B-induced stress fiber formation.



RhoA regulates Activin B-induced stress fiber formation and migration of BMSCs. A RhoA-ROCK-LIMK2-Cofilin signaling node exists and regulates actin stress fiber formation. RhoA regulates Activin B-induced cell migration independent of ROCK.



Better understanding of the molecular mechanisms of BMSCs migration will help optimize therapeutic strategy to target BMSCs at injured tissues.
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Xueer
X
Wang
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Pei
P
Tang
Division of Experimental Hematology and Cancer Biology, Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
Fukun
F
Guo
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Min
M
Zhang
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Yinghua
Y
Chen
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Yuan
Y
Yan
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Zhihui
Z
Tian
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Pengcheng
P
Xu
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Lei
L
Zhang
Key Laboratory of Functional Proteomics of Guangdong Province, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: zlulu70@126.com.
Lu
L
Zhang
Key Laboratory of Construction and Detection in Tissue Engineering of Guangdong Province, Department of Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: zlilyzh@126.com.
Lin
L
Zhang
D051339:Actin Depolymerizing Factors / Q000378:metabolism; D028341:Activins / Q000378:metabolism*; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002465:Cell Movement; D004789:Enzyme Activation; D054461:Lim Kinases / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D008954:Models, Biological; D051381:Rats; D015398:Signal Transduction; D022502:Stress Fibers / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D051339:Actin Depolymerizing Factors; C044147:activin B; D028341:Activins; D054461:Lim Kinases; C490644:Limk2 protein, rat; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein
Activin B; BMSCs; Cell migration; Rho GTPase