TY - JOUR
T1 - Normal differentiation of cultured lens cells after inhibition of gap junction-mediated intercellular communication
AU - Le, Anh Chi N.
AU - Musil, Linda S.
N1 - Funding Information:
We acknowledge Dr. Daniel Goodenough (Harvard Medical School) and Dr. Jean Jiang (University of Texas Health Science Center) for antibodies against Cx45.6 and Cx56 and ongoing advice. We also thank Dr. Ross Johnson (University of Minnesota) for anti-MP28 reagents and Dr. Rae Nishi (Oregon Health Sciences University) and the members of her group for helping us establish embryonic chick lens cultures in our laboratory. We thank John Williams (Vollum Institute) for microinjection experiments. We are especially grateful to Dr. David Beebe (Washington University School of Medicine) for showing us how to prepare epithelial explants and for helpful discussions. This work was supported by Grant EY11117 from the NEI. A.C.L. was supported in part by NIH Training Grant 32DK07680.
PY - 1998/12/1
Y1 - 1998/12/1
N2 - The cells of the vertebrate lens are linked to each other by gap junctions, clusters of intercellular channels that mediate the direct transfer of low-molecular-weight substances between the cytosols of adjoining cells. Although gap junctions are detectable in the unspecialized epithelial cells that comprise the anterior face of the organ, both their number and size are greatly increased in the secondary fiber cells that differentiate from them at the lens equator. In other organs, gap junctions have been shown to play an important role in tissue development and differentiation. It has been proposed, although not experimentally tested, that this may be true in the lens as well. To investigate the function of gap junctions in the development of the lens, we have examined the effect of the gap junction blocker 18β-glycyrrhetinic acid (βGA) on the differentiation of primary cultures (both dissociated cell-derived monolayers and central epithelium explants) of embryonic chick lens epithelial cells. We found that βGA greatly reduced gap junction-mediated intercellular transfer of Lucifer yellow and biocytin throughout the 8-day culture period. βGA did not, however, affect the differentiation of these cells into MP28-expressing secondary fibers. Furthermore, inhibition of gap junctions had no apparent effect on either of the two other types of intercellular (adherens and tight) junctions present in the lens. We conclude that the high level of gap junctional intercellular communication characteristic of the lens equator in vivo is not required for secondary fiber formation as assayed in culture. Up- regulation of gap junctions is therefore likely to be a consequence rather than a cause of lens fiber differentiation and may primarily play a role in lens physiology.
AB - The cells of the vertebrate lens are linked to each other by gap junctions, clusters of intercellular channels that mediate the direct transfer of low-molecular-weight substances between the cytosols of adjoining cells. Although gap junctions are detectable in the unspecialized epithelial cells that comprise the anterior face of the organ, both their number and size are greatly increased in the secondary fiber cells that differentiate from them at the lens equator. In other organs, gap junctions have been shown to play an important role in tissue development and differentiation. It has been proposed, although not experimentally tested, that this may be true in the lens as well. To investigate the function of gap junctions in the development of the lens, we have examined the effect of the gap junction blocker 18β-glycyrrhetinic acid (βGA) on the differentiation of primary cultures (both dissociated cell-derived monolayers and central epithelium explants) of embryonic chick lens epithelial cells. We found that βGA greatly reduced gap junction-mediated intercellular transfer of Lucifer yellow and biocytin throughout the 8-day culture period. βGA did not, however, affect the differentiation of these cells into MP28-expressing secondary fibers. Furthermore, inhibition of gap junctions had no apparent effect on either of the two other types of intercellular (adherens and tight) junctions present in the lens. We conclude that the high level of gap junctional intercellular communication characteristic of the lens equator in vivo is not required for secondary fiber formation as assayed in culture. Up- regulation of gap junctions is therefore likely to be a consequence rather than a cause of lens fiber differentiation and may primarily play a role in lens physiology.
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U2 - 10.1006/dbio.1998.9030
DO - 10.1006/dbio.1998.9030
M3 - Article
C2 - 9851844
AN - SCOPUS:0032396517
SN - 0012-1606
VL - 204
SP - 80
EP - 96
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -