Presence of MUC4 in human milk and at the luminal surfaces of blood vessels.
MUC4 is a heterodimeric membrane mucin, composed of a mucin subunit ASGP-1 (MUC4alpha) and a transmembrane subunit ASGP-2 (MUC4beta), which has been implicated in the protection of epithelial cell surfaces. Surprisingly, development and characterization of a new monoclonal antibody (mAb), called 1G8, against ASGP-2 demonstrated by immunohistochemistry the presence of MUC4 at the luminal surfaces of blood vessels of both normal tissues and tumors. Muc4 was detected with 1G8 and other Muc4 antibodies in blood vessels from humans, rats and mice. This expression of MUC4 in endothelial cells was confirmed by immunoblotting with 1G8 in human umbilical vein endothelial cells (HUVECs), human iliac artery endothelial cells (HIAECs), and human microvascular endothelial cells (HMVECs). MUC4 could be observed on HUVECs grown on either plastic or Matrigel. Finally, MUC4 expression in the three types of endothelial cell lines was confirmed by reverse transcription-polymerase chain reaction (RT-PCR). These results provide, to our knowledge, the first demonstration of a member of the MUC gene family and membrane mucin in blood vessels. As a luminal surface component, the MUC4 is situated to contribute to the non-adhesive luminal surface and to act as an intrinsic protection and survival factor.
Zhang
Jin
J
Department of Cell Biology and Anatomy, University of Miami School of Medicine, Miami, Florida, USA.
Perez
Aymee
A
Yasin
Mohammad
M
Soto
Pedro
P
Rong
Min
M
Theodoropoulos
George
G
Carothers Carraway
Coralie A
CA
Carraway
Kermit L
KL
D000230:Adenocarcinoma; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D006825:Hybridomas; D007150:Immunohistochemistry; D015674:Mammary Neoplasms, Animal; D051379:Mice; D008895:Milk, Human / Q000378:metabolism*; D055264:Mucin-4; D009077:Mucins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000276:immunology / Q000378:metabolism
D000911:Antibodies, Monoclonal; C524658:MUC4 protein, human; C524659:Muc4 protein, mouse; C524660:Muc4 protein, rat; D055264:Mucin-4; D009077:Mucins; D012795:Sialoglycoproteins