TY - JOUR
T1 - Analysis of circadian rhythm gene expression with reference to diurnal pattern of intraocular pressure in mice
AU - Dalvin, Lauren A.
AU - Fautsch, Michael P.
N1 - Publisher Copyright:
© 2015 The Association for Research in Vision and Ophthalmology, Inc.
PY - 2015
Y1 - 2015
N2 - PURPOSE. To determine the expression of circadian rhythm clock genes in the iris–ciliary body complex of mice and their association with the diurnal pattern of intraocular pressure (IOP). METHODS. Thirty wild-type C57BL/6 mice were acclimated to a 12-hour light–dark cycle. Intraocular pressure was measured with a rebound tonometer at six time points daily (circadian time [CT] 2, 6, 10, 14, 18, and 22 hours) for five consecutive days. On day 6, mice were euthanized at CT 2, 6, 10, 14, 18, and 22. Eyes were flash-frozen or fixed in 4% phosphate-buffered paraformaldehyde. Total RNA was extracted from the iris–ciliary body complex, and RNA expression of circadian rhythm genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 was assessed by quantitative real-time PCR. Fixed eyes were paraffin embedded, and immunohistochemistry was performed to localize corresponding proteins (BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2). Linear regression analysis was performed to correlate gene expression with IOP. RESULTS. Intraocular pressure demonstrated a consistent circadian pattern. The clock genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 showed a circadian pattern of expression in the iris–ciliary body complex of mice. Bmal1, Clock, Cry1, Per1, and Per2 gene expression demonstrated statistically significant correlations with diurnal variations of IOP. BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2 proteins were found to be expressed locally in the nonpigmented epithelium of the ciliary body. CONCLUSIONS. Expression patterns of candidate circadian rhythm genes correlates with the diurnal pattern variation of IOP in mouse eyes, indicating a possible mechanism of IOP regulation through these genes.
AB - PURPOSE. To determine the expression of circadian rhythm clock genes in the iris–ciliary body complex of mice and their association with the diurnal pattern of intraocular pressure (IOP). METHODS. Thirty wild-type C57BL/6 mice were acclimated to a 12-hour light–dark cycle. Intraocular pressure was measured with a rebound tonometer at six time points daily (circadian time [CT] 2, 6, 10, 14, 18, and 22 hours) for five consecutive days. On day 6, mice were euthanized at CT 2, 6, 10, 14, 18, and 22. Eyes were flash-frozen or fixed in 4% phosphate-buffered paraformaldehyde. Total RNA was extracted from the iris–ciliary body complex, and RNA expression of circadian rhythm genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 was assessed by quantitative real-time PCR. Fixed eyes were paraffin embedded, and immunohistochemistry was performed to localize corresponding proteins (BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2). Linear regression analysis was performed to correlate gene expression with IOP. RESULTS. Intraocular pressure demonstrated a consistent circadian pattern. The clock genes Bmal1, Clock, Cry1, Cry2, Per1, and Per2 showed a circadian pattern of expression in the iris–ciliary body complex of mice. Bmal1, Clock, Cry1, Per1, and Per2 gene expression demonstrated statistically significant correlations with diurnal variations of IOP. BMAL1, CLOCK, CRY1, CRY2, PER1, and PER2 proteins were found to be expressed locally in the nonpigmented epithelium of the ciliary body. CONCLUSIONS. Expression patterns of candidate circadian rhythm genes correlates with the diurnal pattern variation of IOP in mouse eyes, indicating a possible mechanism of IOP regulation through these genes.
KW - Aqueous outflow
KW - Circadian rhythm
KW - Clock genes
KW - Intraocular pressure
KW - Iris–ciliary body complex
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U2 - 10.1167/iovs.15-16449
DO - 10.1167/iovs.15-16449
M3 - Article
C2 - 25813988
AN - SCOPUS:84939621814
SN - 0146-0404
VL - 56
SP - 2657
EP - 2663
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 4
ER -