Background: The lymphatic system regulates interstitial fluid and protein balance and modulates
immune responses by regulating leukocyte and antigen traffic to lymph nodes. The present
article describes a stable mouse lymphatic endothelial cell line from mesenteric adventitial
tissue (SV-LEC) which is distinct from blood aortic (AEC) and venous (VEC) endothelial cells,
based on expression of several lymphatic markers (e.g., Prox-1, LYVE-1, Flt-4). SV-LEC also expresses
MAdCAM-1 in response to TNF- α, an effect seen in VEC, but not AEC.
Methods and Results: Lymphatic endothelial cells (SV-LEC) were isolated from mesenteric
adventitia from mice expressing temperature-sensitive SV40 large T ('Immortomouse', H-2KbtsA58)
selected with hypoxia culture in D-valine-substituted MEM supplemented with VEGFC
in a low oxygen atmosphere (0% O2, 5% CO2, and 95% N2) with 5 mM thioglycolate. Expression
of lymphatic-specific markers (Flt-4, LYVE-1, Prox-1) and the tight junction proteins
(ZO-1) were examined by RT-PCR, immunoblotting, and fluorescent microscopy.
MAdCAM-1 (a high endothelial venular marker) expression was also examined in response
to TNF- α IL-1 βand IFN- γ.
Results: Message for Flt-4 and LYVE-1 was detected on SV-LEC. Immunoblotting for
LYVE-1 and Prox-1 showed strong expression on SV-LEC and VEC, but not AEC. Occludin
expression was seen in all cell types, junctional ZO-1 was detected at SV-LEC and VEC junctions,
not AEC.
Conclusion: SV-LEC expresses several lymphatic endothelial markers, some of which are
shared with VEC, but not AEC, and may represent a useful system for modeling lymphatic
function in vitro.
