Opposite Regulation of Transepithelial Electrical Resistance and Paracellular Permeability by Rho in Madin-Darby Canine Kidney Cells*
- Hiroshi Hasegawa‡,
- Hirotada Fujita‡,
- Hironori Katoh‡,
- Junko Aoki‡,
- Kazuhiro Nakamura‡,
- Atsushi Ichikawa§ and
- Manabu Negishi‡¶
- From the Departments of ‡Molecular Neurobiology and§Physiological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
Abstract
Small GTPase Rho has been thought to be important for the formation and the maintenance of tight junction in epithelial cells, but the role of Rho in the regulation of barrier function of tight junction is not well understood. We here examined whether Rho was involved in the barrier function of tight junction in Madin-Darby canine kidney (MDCK) cells. The activation of prostaglandin EP3β receptor, coupled to a Rho activation pathway, induced the increase in transepithelial electrical resistance (TER) but the increase in paracellular flux of mannitol in the preformed monolayer of the MDCK cells expressing the EP3β receptor. This effect of the EP3 receptor was mimicked by the expression of constitutively active RhoA but not by active Rac1 in MDCK cells, using an isopropyl-β-d-thiogalactoside-inducible expression system. On the other hand, the activation of EP3β receptor suppressed the elevation of TER and the decrease in paracellular mannitol flux during Ca2+ switch-induced tight junction formation, whereas the expression of active RhoA or Rac1 did not apparently affect the TER development in the Ca2+ switch. These results demonstrate that the EP3 receptor and active RhoA regulate permeabilities of ionic and nonionic molecules in opposite directions in the preformed monolayer, and the EP3 receptor suppresses the elevation of TER during the tight junction formation.
Footnotes
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↵* This work was supported in part by a Grants-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan and grants from the Asahi Glass Research Foundation and the Mochida Memorial Foundation for Medical and Pharmaceutical Research.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵¶ To whom correspondence should be addressed: Dept. of Molecular Neurobiology, Faculty of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan. Tel.: 81-75-753-4547; Fax: 81-75-753-4557; E-mail: mnegishi@pharm.kyoto-u.ac.jp.
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↵2 H. Hasegawa, H. Fujita, and M. Negishi, unpublished observations.
- Abbreviations:
- TER
-
transepithelial electrical resistance
- PT
-
pertussis toxin
- MDCK
-
Madin-Darby canine kidney
- 8-br-cAMP
-
8-bromo-cyclic AMP
- HA
-
hemagglutinin
- DMEM
-
Dulbecco’s modified Eagle’s medium
- IPTG
-
isopropyl-β-D thiogalactoside
- PBS
-
phosphate-buffered saline
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- Received December 31, 1998.
- Revision received April 12, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
