TY - JOUR
T1 - The zinc sensing receptor, ZnR/GPR39, controls proliferation and differentiation of colonocytes and thereby tight junction formation in the colon
AU - Cohen, L.
AU - Sekler, I.
AU - Hershfinkel, M.
N1 - Funding Information: Acknowledgements. This work was supported by the Israel Science Foundation (Grant 513/09 to M.H.). The GPR39 KO mice were kindly provided by D Moechars from Johnson & Johnson Pharmaceutical Research and Development, a Division of Janssen Pharmaceutica.
PY - 2014/1/1
Y1 - 2014/1/1
N2 - The intestinal epithelium is a renewable tissue that requires precise balance between proliferation and differentiation, an essential process for the formation of a tightly sealed barrier. Zinc deficiency impairs the integrity of the intestinal epithelial barrier and is associated with ulcerative and diarrheal pathologies, but the mechanisms underlying the role of Zn2+ are not well understood. Here, we determined a role of the colonocytic Zn 2+ sensing receptor, ZnR/GPR39, in mediating Zn2+- dependent signaling and regulating the proliferation and differentiation of colonocytes. Silencing of ZnR/GPR39 expression attenuated Zn2+- dependent activation of ERK1/2 and AKT as well as downstream activation of mTOR/p70S6K, pathways that are linked with proliferation. Consistently, ZnR/GPR39 silencing inhibited HT29 and Caco-2 colonocyte proliferation, while not inducing caspase-3 cleavage. Remarkably, in differentiating HT29 colonocytes, silencing of ZnR/GPR39 expression inhibited alkaline phosphatase activity, a marker of differentiation. Furthermore, Caco-2 colonocytes showed elevated expression of ZnR/GPR39 during differentiation, whereas silencing of ZnR/GPR39 decreased monolayer transepithelial electrical resistance, suggesting compromised barrier formation. Indeed, silencing of ZnR/GPR39 or chelation of Zn2+ by the cell impermeable chelator CaEDTA was followed by impaired expression of the junctional proteins, that is, occludin, zonula-1 (ZO-1) and E-cadherin. Importantly, colon tissues of GPR39 knockout mice also showed a decrease in expression levels of ZO-1 and occludin compared with wildtype mice. Altogether, our results indicate that ZnR/GPR39 has a dual role in promoting proliferation of colonocytes and in controlling their differentiation. The latter is followed by ZnR/GPR39-dependent expression of tight junctional proteins, thereby leading to formation of a sealed intestinal epithelial barrier. Thus, ZnR/GPR39 may be a therapeutic target for promoting epithelial function and tight junction barrier integrity during ulcerative colon diseases.
AB - The intestinal epithelium is a renewable tissue that requires precise balance between proliferation and differentiation, an essential process for the formation of a tightly sealed barrier. Zinc deficiency impairs the integrity of the intestinal epithelial barrier and is associated with ulcerative and diarrheal pathologies, but the mechanisms underlying the role of Zn2+ are not well understood. Here, we determined a role of the colonocytic Zn 2+ sensing receptor, ZnR/GPR39, in mediating Zn2+- dependent signaling and regulating the proliferation and differentiation of colonocytes. Silencing of ZnR/GPR39 expression attenuated Zn2+- dependent activation of ERK1/2 and AKT as well as downstream activation of mTOR/p70S6K, pathways that are linked with proliferation. Consistently, ZnR/GPR39 silencing inhibited HT29 and Caco-2 colonocyte proliferation, while not inducing caspase-3 cleavage. Remarkably, in differentiating HT29 colonocytes, silencing of ZnR/GPR39 expression inhibited alkaline phosphatase activity, a marker of differentiation. Furthermore, Caco-2 colonocytes showed elevated expression of ZnR/GPR39 during differentiation, whereas silencing of ZnR/GPR39 decreased monolayer transepithelial electrical resistance, suggesting compromised barrier formation. Indeed, silencing of ZnR/GPR39 or chelation of Zn2+ by the cell impermeable chelator CaEDTA was followed by impaired expression of the junctional proteins, that is, occludin, zonula-1 (ZO-1) and E-cadherin. Importantly, colon tissues of GPR39 knockout mice also showed a decrease in expression levels of ZO-1 and occludin compared with wildtype mice. Altogether, our results indicate that ZnR/GPR39 has a dual role in promoting proliferation of colonocytes and in controlling their differentiation. The latter is followed by ZnR/GPR39-dependent expression of tight junctional proteins, thereby leading to formation of a sealed intestinal epithelial barrier. Thus, ZnR/GPR39 may be a therapeutic target for promoting epithelial function and tight junction barrier integrity during ulcerative colon diseases.
UR - http://www.scopus.com/inward/record.url?scp=84903795499&partnerID=8YFLogxK
U2 - https://doi.org/10.1038/cddis.2014.262
DO - https://doi.org/10.1038/cddis.2014.262
M3 - Article
C2 - 24967969
SN - 2041-4889
VL - 5
JO - Cell Death and Disease
JF - Cell Death and Disease
IS - 6
M1 - e1307
ER -
