Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Validation of microRNAs as Biomarkers of Salivary Gland Inflammation in Sjgren's Syndrome.

Emamian1,  Seyed M., Alevizos1,  Ilias, Illei2,  Gabor G.

NIDCR
NIDCR, NIH #10 1N114, Bethesda, MD

The diagnosis of Sjögren's syndrome (SS) is based on a number of diagnostic criteria, including the assessment of inflammation (quantified by the focus score) in a minor salivary gland (MSG) biopsy. MicroRNAs (miRNAs) are a group of RNAs, 18–24 nucleotides in length, involved in the regulation of cellular processes. miRNAs are promising as biomarkers as they are resistant to degradation and can be isolated from various sources including formalin-fixed, paraffin-embedded (FFPE) biopsies. In a preliminary study done on frozen MSG biopsies we have demonstrated that the relative expression of two miRNAs showed good association with various degrees of inflammation in a small cohort.

Purpose:

To validate hsa-mir-574-3p and hsa-mir-768-3p as biomarkers of inflammation in a larger cohort of subjects.

Methods:

the training cohort consisted of 49 subjects 33 with primary Sjögren's patients and 16 non-Sjogren's controls. In the validation cohort 49 subjects had pSS, 26 had sicca symptoms but no SS and 12 were healthy controls. miRNA was isolated from FFPE biopsies from MSGs. The relative expression of hsa-mir-574-3p and hsa-mir-768-3p was determined by calculating the difference of their respective threshold level (DCt) from the same quantitative TaqMan Real Time PCR reaction. A one unit difference in the Ct between the two microRNAs represents a two-fold difference of expression between the two microRNAs.

Results:

Using a teaching cohort of 49 subjects, we first showed the DCt of hsa-mir-574-3p and hsa-mir-768-3p derived from FFPE samples can distinguish samples from Sjögren's from non-Sjögren's MSGs regardless of focus score (p 0.0001, one-way analysis of variance) as well as groups with various degree of inflammation. To validate the applicability of these miRNAs as biomarkers we determined the correlation between individual focus scores and the DCt in an independent set of 87 subjects.

A Pearson's correlation analysis showed a significant relationship between DCt of hsa-mir-574-3p and hsa-mir-768-3p and focus scores (r=0.85, r2=0.72, p= 0.0001).

Conclusion:

The relative expression of hsa-mir-574-3p and hsamir-768-3p shows a strong correlation with focus scores in MSGs of Sjögren's patients validating these miRNAs are biomarkers of MSG inflammation and suggesting that they may be used to reduce the subjectivity involved in the diagnosis of SS.

To cite this abstract, please use the following information:
Emamian, Seyed M., Alevizos, Ilias, Illei, Gabor G.; Validation of microRNAs as Biomarkers of Salivary Gland Inflammation in Sjgren's Syndrome. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1918
DOI: 10.1002/art.29683

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