TY - JOUR
T1 - Expression of pI(Cln) mRNA in cultured bovine lens epithelial cells
T2 - Response to changes in cell volume
AU - Reeves, Rustin E.
AU - Sanchez-Torres, Juan
AU - Coca-Prados, Miguel
AU - Cammarata, Patrick R.
N1 - Funding Information:
This work represents partial fulfillment of the requirements for the doctoral degree for RER. The authors wish to thank Mortimer M. Civan for helpful discussions. Supported by National Health Service Award EY05570 (PRC).
PY - 1998
Y1 - 1998
N2 - Purpose. The authors recently established a link between swelling-activated myo-inositol efflux and chloride movement via anion channels in cultured bovine lens epithelial cells (BLECs). To further define this pathway, the relationship between cell volume, myo-inositol movement and mRNA expression of pI(Cln), a proposed chloride channel regulatory protein was investigated. Methods. To demonstrate the effect of cell volume changes on pI(Cln) transcription, BLECs were exposed to either hypertonic or hypotonic medium conditions. For rapid cellular shrinkage, BLECs were maintained at confluence in physiologic medium (257 ± 2 mosm) then transferred to sodium hypertonic medium (473 ± 6 mosm) or raffinose hypertonic medium (452 ± 2 mosm). For rapid cellular swelling, cells were switched from sodium hypertonic medium to physiologic medium ± tamoxifen. The expression of pI(Cln) mRNA was determined by Northern blot analysis. Results. Upon cell volume reduction (increasing intracellular osmolality), BLECs upregulate the expression of pI(Cln) mRNA. Contrastly, when cell volume rapidly increases (decreasing intracellular osmolality), BLECs moderately downregulate pI(Cln) mRNA, with expression levels reaching near physiologic control by 24 h. Blockage of swelling-activated chloride movement and osmolyte efflux with either tamoxifen or niflumic acid enhances the downregulation of pI(Cln) mRNA expression. Conclusions. In cultured BLECs, pI(Cln) transcriptional regulation appears to be responsive to cell volume fluctuations. These data suggest a converse relationship exists between pI(Cln) mRNA expression and changes in cell volume.
AB - Purpose. The authors recently established a link between swelling-activated myo-inositol efflux and chloride movement via anion channels in cultured bovine lens epithelial cells (BLECs). To further define this pathway, the relationship between cell volume, myo-inositol movement and mRNA expression of pI(Cln), a proposed chloride channel regulatory protein was investigated. Methods. To demonstrate the effect of cell volume changes on pI(Cln) transcription, BLECs were exposed to either hypertonic or hypotonic medium conditions. For rapid cellular shrinkage, BLECs were maintained at confluence in physiologic medium (257 ± 2 mosm) then transferred to sodium hypertonic medium (473 ± 6 mosm) or raffinose hypertonic medium (452 ± 2 mosm). For rapid cellular swelling, cells were switched from sodium hypertonic medium to physiologic medium ± tamoxifen. The expression of pI(Cln) mRNA was determined by Northern blot analysis. Results. Upon cell volume reduction (increasing intracellular osmolality), BLECs upregulate the expression of pI(Cln) mRNA. Contrastly, when cell volume rapidly increases (decreasing intracellular osmolality), BLECs moderately downregulate pI(Cln) mRNA, with expression levels reaching near physiologic control by 24 h. Blockage of swelling-activated chloride movement and osmolyte efflux with either tamoxifen or niflumic acid enhances the downregulation of pI(Cln) mRNA expression. Conclusions. In cultured BLECs, pI(Cln) transcriptional regulation appears to be responsive to cell volume fluctuations. These data suggest a converse relationship exists between pI(Cln) mRNA expression and changes in cell volume.
KW - Bovine lens epithelial cells
KW - Chloride channel
KW - Myo-inositol
KW - Regulatory protein
KW - Volume regulation
UR - http://www.scopus.com/inward/record.url?scp=0031688041&partnerID=8YFLogxK
U2 - 10.1076/ceyr.17.9.861.5140
DO - 10.1076/ceyr.17.9.861.5140
M3 - Article
C2 - 9746432
AN - SCOPUS:0031688041
VL - 17
SP - 861
EP - 869
JO - Current Eye Research
JF - Current Eye Research
SN - 0271-3683
IS - 9
ER -