Dataset Information

Conjunctival MicroRNA expression in inflammatory trachomatous scarring.

ABSTRACT:

Purpose

Trachoma is a fibrotic disease of the conjunctiva initiated by Chlamydia trachomatis infection. This blinding disease affects over 40 million people worldwide yet the mechanisms underlying its pathogenesis remain poorly understood. We have investigated host microRNA (miR) expression in health (N) and disease (conjunctival scarring with (TSI) and without (TS) inflammation) to determine if these epigenetic differences are associated with pathology.

Methods

We collected two independent samples of human conjunctival swab specimens from individuals living in The Gambia (n?=?63 & 194). miR was extracted, and we investigated the expression of 754 miR in the first sample of 63 specimens (23 N, 17 TS, 23 TSI) using Taqman qPCR array human miRNA genecards. Network and pathway analysis was performed on this dataset. Seven miR that were significantly differentially expressed between different phenotypic groups were then selected for validation by qPCR in the second sample of 194 specimens (93 N, 74 TS, 22 TSI).

Results

Array screening revealed differential expression of 82 miR between N, TS and TSI phenotypes (fold change >3, p<0.05). Predicted mRNA targets of these miR were enriched in pathways involved in fibrosis and epithelial cell differentiation. Two miR were confirmed as being differentially expressed upon validation by qPCR. miR-147b is significantly up-regulated in TSI versus N (fold change?=?2.3, p?=?0.03) and miR-1285 is up-regulated in TSI versus TS (fold change?=?4.6, p?=?0.005), which was consistent with the results of the qPCR array.

Conclusions

miR-147b and miR-1285 are up-regulated in inflammatory trachomatous scarring. Further investigation of the function of these miR will aid our understanding of the pathogenesis of trachoma.

SUBMITTER: Derrick T

PROVIDER: S-EPMC3597489 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Conjunctival MicroRNA expression in inflammatory trachomatous scarring.

Derrick Tamsyn T Roberts Chrissy h Ch Rajasekhar Megha M Burr Sarah E SE Joof Hassan H Makalo Pateh P Bailey Robin L RL Mabey David C W DC Burton Matthew J MJ Holland Martin J MJ

PLoS neglected tropical diseases 20130314 3

<h4>Purpose</h4>Trachoma is a fibrotic disease of the conjunctiva initiated by Chlamydia trachomatis infection. This blinding disease affects over 40 million people worldwide yet the mechanisms underlying its pathogenesis remain poorly understood. We have investigated host microRNA (miR) expression in health (N) and disease (conjunctival scarring with (TSI) and without (TS) inflammation) to determine if these epigenetic differences are associated with pathology.<h4>Methods</h4>We collected two i ...[more]

PMID: 23516655

Similar Datasets

Project description:Ocular infection with Chlamydia trachomatis (trachoma) is the leading cause of blindness that results from infection. Chronic inflammation is believed to drive the scarring process and the progressive blinding disease, however the mechanisms by which this occurs are not completely understood. We hypothesized that Micro RNA (miRNA), as key regulators of genes in inflammatory pathways, are involved in the immunopathogenesis and tissue remodeling observed in trachoma. Conjunctival swabs were collected from a total of 63 individuals resident in trachoma endemic communities in The Gambia, West Africa. MiRNA was extracted from the conjunctival swabs of 23 healthy controls (N), 18 cases with trachomatous scarring (TS) and 22 cases with trachomatous scarring in the presence of clinically significant inflammation (TSI) using Qiagen Allprep DNA/RNA/protein kits. Following reverse transcription and pre-amplification, quantitative RT-PCR was performed using TaqMan Array Human MicroRNA genecards (Av2.0 and Bv3.0) on a 7900HT thermal cycler (Life Technologies, Inc). A total of 754 of the most well characterised unique human miRNA from miRBase (www.mirbase.org/) were screened. Data from each array were uploaded and analysed using the high throughput qPCR package in bioconductor R. Samples with a global miRNA median cycle threshold of 40 were filtered out. A and B cards were analysed separately due to differences in performance of samples on each card. In the A card group 40 samples were normalized and tested: 8 TSI, 16 TS and 16 N. In the B card group 29 samples were normalized and tested: 6 TSI, 13 TS and 10 N. Results were normalized by rank invariant normalization as it reduced the coefficient of variation and increased sample distribution homology more than any other normalization procedure tested. Data in each group were tested for differential expression by Limma. 63 total Samples. In the A card group 40 samples were normalized and tested: 8 TSI, 16 TS and 16 N. In the B card group 29 samples were normalized and tested: 6 TSI, 13 TS and 10 N. Results were normalized by rank invariant normalization as it reduced the coefficient of variation and increased sample distribution homology more than any other normalization procedure tested.

Project description:Trachoma is a poorly understood immuno-fibrogenic disease process, initiated by Chlamydia trachomatis (Ct). Differences in conjunctival gene expression profiles between Ethiopians with trachomatous trichiasis (with (TTI) and without (TT) inflammation) and controls (NC) were investigated to identify relevant host responses. Tarsal conjunctival swab samples were collected for RNA isolation and Ct PCR. Transcriptome-wide microarray experiments were conducted on 42 samples (TTI 13, TT 15, NC14). Specific results were confirmed using multiplex quantitative RT-PCR for 16 mRNA targets in an independent collection of case-control samples: 386 case-control pairs (TTI 244, TT 142, NC 386). The gene expression profiles of cases were consistent with: squamous metaplasia (Keratins, SPRR), pro-inflammatory cytokine production (IL-1β, CXCL5, S100A7) and tissue remodelling (MMP7, MMP9, MMP12, HAS3). There was no difference in the level of IFNG between cases and controls. However, cases had increased INDO, NOS2A, and IL13RA2 and reduced IL13. Ct was detected in 1/772. Cases show evidence of ongoing inflammation and tissue remodelling, which were more marked where clinical inflammation was also present. Significantly, these processes appear to be active in the absence of current Ct infection. There was limited evidence of a TH1 response (INDO, NOS2A) and no association between a TH2 response and cases. The epithelium appears actively involved in late cicatricial stages of trachoma through production of pro-inflammatory factors (IL-1β, CXCL5, S100A7). Longitudinal studies are needed to investigate which aetiological factors and pathways are associated with progressive scarring and whether simply controlling chlamydial infection will halt progression in people with established cicatricial disease. Case - control study. Conjunctival swab samples were collected from people with trachomatous trichiasis with (TTI) and without (TT) clinically visable inflammation compared to normal controls (C). Total RNA extracted and analysed on the Illumina WG-6 platrom. Additional extensive qRT-PCR work done on a large set of case-control pairs.

Project description:BackgroundAssociations between repeated ocular infections with Chlamydia trachomatis in childhood and conjunctival scarring in adulthood are well established. Trachomatous scarring (TS) in children has also been observed in hyper-endemic areas, but data are scant regarding childhood scarring in areas where trachoma has been reduced to hypo-endemic levels.Methods/principle findingsIn this cross-sectional study, a random sample of children, ages 1-9 years, were selected from 38 communities in the formerly hyper-endemic district of Kongwa, Tanzania. Each participant received an ocular examination and eye-swab test for C. trachomatis infection. Conjunctival photographs were taken and analyzed at 5x magnification to determine scarring presence and severity. Community-level case clustering was assessed using intra-class correlation coefficients, and associations between TS presence and demographic/clinical factors were assessed using contingency table analyses. 1,496 children (78% of eligible) participated in this study. The mean age was 5.5 years and 51% were female. Scarring prevalence was 2.1% (95% CI: 1.5%- 3.0%). The prevalence of follicular trachoma and ocular C. trachomatis infection were 3.2% and 6.5%, respectively. Most TS cases (68.7%) fell into the mildest category, grade S1. 18.7% were grade S2; 12.6% were grade S3. No significant associations were seen between TS presence and age, sex, follicular trachoma, or active ocular C. trachomatis infection (p-values: 0.14, 0.48, 0.27, 0.15, respectively). Thirty communities (78.9%) had 0-1 TS cases, and the most seen in any single community was four cases. Three years ago, follicular trachoma prevalence averaged 4.9% in communities with 0-1 TS cases, but 7.6% in communities with 2-4 TS cases (p-value: 0.08).ConclusionsIn this formerly hyper-endemic district of Tanzania, TS was rare in 1-9 year-olds and usually mild when present. Communities with higher rates of follicular trachoma in the past were more likely to have ?2 cases of scarring, but the association was not statistically significant.

Dataset Information

Conjunctival MicroRNA expression in inflammatory trachomatous scarring.

Purpose

Methods

Results

Conclusions

Publications

Conjunctival MicroRNA expression in inflammatory trachomatous scarring.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets