scholarly journals PDGF signaling directs cardiomyocyte movement toward the midline during heart tube assembly

2016 ◽  
Author(s):  
Joshua Bloomekatz ◽  
Reena Singh ◽  
Owen W.J. Prall ◽  
Ariel C. Dunn ◽  
Megan Vaughan ◽  
...  

AbstractCommunication between neighboring tissues plays a central role in guiding organ morphogenesis. During heart tube assembly, interactions with the adjacent endoderm control the medial movement of cardiomyocytes, a process referred to as cardiac fusion. However, the molecular underpinnings of this endodermal-myocardial relationship remain unclear. Here, we show an essential role for platelet-derived growth factor receptor alpha (Pdgfra) in directing cardiac fusion. In both zebrafish and mouse, mutation of pdgfra inhibits cardiac fusion and can lead to cardia bifida. Timelapse analysis of individual cardiomyocyte trajectories reveals misdirected cells in zebrafish pdgfra mutants, suggesting that PDGF signaling steers cardiomyocytes toward the midline. Intriguingly, the ligand pdgfaa is expressed in the endoderm medial to the pdgfra-expressing myocardial precursors. Ectopic expression of pdgfaa interferes with cardiac fusion, consistent with an instructive role for PDGF signaling. Together, these data uncover a novel mechanism through which endodermal-myocardial communication guides the cell movements that initiate cardiac morphogenesis.IMPACT STATEMENTStudies in zebrafish and mouse implicate the PDGF signaling pathway in the communication between the endoderm and the myocardium that drives medial myocardial movement and thereby initiates cardiac morphogenesis.

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Joshua Bloomekatz ◽  
Reena Singh ◽  
Owen WJ Prall ◽  
Ariel C Dunn ◽  
Megan Vaughan ◽  
...  

Communication between neighboring tissues plays a central role in guiding organ morphogenesis. During heart tube assembly, interactions with the adjacent endoderm control the medial movement of cardiomyocytes, a process referred to as cardiac fusion. However, the molecular underpinnings of this endodermal-myocardial relationship remain unclear. Here, we show an essential role for platelet-derived growth factor receptor alpha (Pdgfra) in directing cardiac fusion. Mutation of pdgfra disrupts heart tube assembly in both zebrafish and mouse. Timelapse analysis of individual cardiomyocyte trajectories reveals misdirected cells in zebrafish pdgfra mutants, suggesting that PDGF signaling steers cardiomyocytes toward the midline during cardiac fusion. Intriguingly, the ligand pdgfaa is expressed in the endoderm medial to the pdgfra-expressing myocardial precursors. Ectopic expression of pdgfaa interferes with cardiac fusion, consistent with an instructive role for PDGF signaling. Together, these data uncover a novel mechanism through which endodermal-myocardial communication can guide the cell movements that initiate cardiac morphogenesis.


Blood ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 1374-1376 ◽  
Author(s):  
Els Lierman ◽  
Cedric Folens ◽  
Elizabeth H. Stover ◽  
Nicole Mentens ◽  
Helen Van Miegroet ◽  
...  

Abstract The FIP1L1-PDGFRA oncogene is a common cause of chronic eosinophilic leukemia (CEL), and encodes an activated tyrosine kinase that is inhibited by imatinib. FIP1L1-PDGFRA–positive patients with CEL respond to low-dose imatinib therapy, but resistance due to acquired T674I mutation has been observed. We report here the identification of sorafenib as a potent inhibitor of the FIP1 like 1–platelet-derived growth factor receptor alpha (FIP1L1-PDGFRα) (T674I) mutant. Sorafenib inhibited the proliferation of FIP1L1-PDGFRα and FIP1L1-PDGFRα(T674I)–transformed Ba/F3 cells and induced apoptosis of the EOL-1 cell line at a low nanomolar concentration. Western blot analysis confirmed that these effects were due to a direct effect on FIP1L1-PDGFRα and FIP1L1-PDGFRα(T674I). Sorafenib was recently approved for the treatment of renal cell carcinoma. Our data suggest that low doses of sorafenib could be efficient for the treatment of FIP1L1-PDGFRA–positive CEL and could be used to overcome resistance to imatinib associated with the T674I mutation.


mBio ◽  
2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Jing Liu ◽  
Adam Vanarsdall ◽  
Dong-Hua Chen ◽  
Andrea Chin ◽  
David Johnson ◽  
...  

HCMV is a herpesvirus that infects a large percentage of the adult population and causes significant levels of disease in immunocompromised individuals and birth defects in the developing fetus. The virus encodes a complex protein machinery that coordinates infection of different cell types in the body, including a trimer formed of gH, gL, and gO subunits.


Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5195-5205 ◽  
Author(s):  
A.F. Ramsdell ◽  
H.J. Yost

The rightward looping of the primary heart tube is dependent upon upstream patterning events that establish the vertebrate left-right axis. In Xenopus, a left-sided Vg1 signaling pathway has been implicated in instructing cells to adopt a ‘left-sided identity’; however, it is not known whether ‘right-sided identity’ is acquired by a default pathway or by antagonism of Vg1 signaling. Here, we propose that an antagonistic, BMP/ALK2/Smad-mediated signaling pathway is active on the right side of the Xenopus embryo. Truncated ALK2 receptor expression on the right side of the blastula elicits heart reversals and altered nodal expression. Consistent with these findings, constitutively active ALK2 (CA-ALK2) receptor expression on the left side of the blastula also elicits heart reversals and altered nodal expression. Coexpression of CA-ALK2 with mature Vg1 ligand results in predominantly left-sided nodal expression patterns and normal heart looping, demonstrating that the ALK2 pathway can ‘rescue’ left-right reversals that otherwise occur following right-sided misexpression of mature Vg1 ligand alone. Results with chimeric precursor proteins indicate that the mature domain of BMP ligands can mimic the ability of the ALK2 signaling pathway to antagonize the Vg1 pathway. Consistent with the observed antagonism between BMP and Vg1 ligands, left-sided ectopic expression of Xolloid results in heart reversals. Moreover, ectopic expression of Smad1 or Smad7 identified two downstream modulators of the BMP/ALK2 signaling pathway that also can regulate cardiac orientation. Collectively, these results define a BMP/ALK2-mediated pathway on the right side of the Xenopus embryo and, moreover, suggest that left-right patterning preceding cardiac morphogenesis involves the activation of two distinct and antagonistic, left- and right-sided TGF(beta)-related signaling pathways.


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