Pathway-focused arrays reveal increased matrix metalloproteinase-7 (matrilysin) transcription in trachomatous trichiasis.
OBJECTIVE
Several genes that are associated with protection from or susceptibility to trachomatous trichiasis (TT) have been identified through genetic association studies. Yet there have been few studies in which gene expression profiles were assessed in TT cases and disease-free controls. The purpose was to identify genes that are differentially expressed in the upper tarsal conjunctiva of subjects with TT.


METHODS
Pathway-focused gene arrays were used to screen conjunctival RNA expression of 226 gene transcripts of interest. The screening was followed by validation of differentially expressed genes by qRT-PCR on an independent set of samples. Three different techniques were then used to test for quantitative differences in the recovered conjunctival protein fraction.


RESULTS
Focused arrays identified a set of 13 differentially expressed genes. Validation by qRT-PCR confirmed differential expression in four of these genes (COL1A1, COL7A1, MMP7, and TLR6). Increased expression of MMP7 was the only consistent differentially regulated gene in the conjunctival samples of trichiasis subjects. MMP7 was present in isolated conjunctival proteins and in the tissue culture supernatants of peripheral blood lymphocytes after stimulation.


CONCLUSIONS
There is an imbalance in extracellular matrix turnover with minimal contribution of adaptive immune responses at this stage of trichiasis. There was little evidence of broad differential expression in genes characteristic of polar responses of adaptive T cells or macrophages. The control of the MMP7 response and its activity appears significant in the fibrotic changes observed in TT.
Holland
Martin J
MJ
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK. martin.holland@lshtm.ac.uk
Jeffries
David
D
Pattison
Michael
M
Korr
Gerit
G
Gall
Alevtina
A
Joof
Hassan
H
Manjang
Ahmed
A
Burton
Matthew J
MJ
Mabey
David C W
DC
Bailey
Robin L
RL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003229:Conjunctival Diseases / Q000453:epidemiology / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005140:Eyelashes; D005260:Female; D005714:Gambia / Q000453:epidemiology; D006201:Hair Diseases / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000235:genetics*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014141:Trachoma / Q000453:epidemiology / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics*
D004272:DNA, Mitochondrial; D012333:RNA, Messenger; C060932:MMP7 protein, human; D020783:Matrix Metalloproteinase 7