Investigation of beta defensin gene expression in the ocular anterior segment by semiquantitative RT-PCR.
OBJECTIVE
To determine if beta defensins are expressed in the anterior segment of the eye and to determine the temporal pattern of expression using a real time semiquantitative reverse transcription polymerase chain reaction (RT-PCR).


METHODS
Ocular tissue (corneal epithelium, conjunctiva, iris, and lens capsule) was collected from 23 patients undergoing surgery. Serial corneal or conjunctival impression cytology was performed on a separate group of 10 patients undergoing corneal tunnel phacoemulsification or trabeculectomy. The samples were analysed for beta defensin mRNA by semiquantitative RT-PCR and the mRNA standardised for cell numbers.


RESULTS
RT-PCR amplified beta defensin 1 mRNA from all lens capsule (six) and corneal (five) samples and all but one of the conjunctival (six) and iris samples (six). beta Defensin 2 mRNA was amplified from three of five corneal, two of six conjunctival, and none of the iris or capsule samples. The impression cytology samples demonstrated a decline in defensin expression over the three time points studied. There were no false positive results from either the no-RT or negative control samples.


CONCLUSIONS
This preliminary study confirms that natural antibacterial peptides are expressed in the anterior segment of the eye. There appears to be a pattern to the expression with inducible beta defensin 2 not expressed intraocularly and higher levels of beta defensin 1 than beta defensin 2 expressed in extraocular tissue. The implication is that beta defensin 1 is constitutively produced in ocular tissues and represents a key component of the innate immune system.
Lehmann
O J
OJ
Moorfields Eye Hospital, London, UK. ojlehmann@yahoo.com
Hussain
I R
IR
Watt
P J
PJ
D000869:Anterior Eye Segment / Q000378:metabolism*; D003228:Conjunctiva / Q000378:metabolism; D023082:Defensins; D019573:Epithelium, Corneal / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007498:Iris / Q000378:metabolism; D007903:Lens Capsule, Crystalline / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D023082:Defensins; D011506:Proteins; D012333:RNA, Messenger