The regulative expression of paracellular tight junction genes in the duodenum and kidney of calbindin-D9k and/or –D28k knockout mice

Presentation Number: SAT-409
Date of Presentation: June 15th, 2013

Inho Hwang and Eui-Bae Jeung*
College of Veterinary Med, Cheongju Chungbuk, Korea, Republic of (South)

Abstract

The calcium absorption is regulated by both active (trans-cellular) and passive (para-cellular) pathways. Although each pathway has been progressively studied, the correlation of both pathways has not been elucidated yet. In the previous studies, calbindin-D9k (CaBP-9k) and -D28k (CaBP-28k) are shown to be involved in the transcellular pathway by buffering intracellular calcium levels. The rate of the passive calcium transport is determined by the expression of tight junction genes. Especially, members of claudin family that form cation selective ion channels are critical for calcium (re)absorption. In this study, the effect of the dietary supplementation of calcium and/or vitamin D on the tight junction gene expressions (occludin, ZO-1, JAM-A, and claudins) was examined in the CaBP-9k and/or -28k gene knockout (KO) mice. In the normal diet groups, the most of tight junction genes in the duodenum, but not in the kidney were significantly increased in CaBP-9k KO mice than wild-type (WT) mice. In the calcium and vitamin D deficient groups, the tight junction genes were significantly decreased in the duodenum of CaBP-9k KO mice but were increased in the kidney of CaBP-28k and CaBP-9k/28k KO (DKO) mice. In this study, the expressional patterns of these tight junction genes in the CaBPs KO mice were oppositely appeared in duodenum and kidney, suggesting that active and passive calcium transport pathways may cooperate to transport calcium in these organs.

 

Nothing to Disclose: IH, EBJ