MicroRNA (miRNA) may have utility as a screening biomarker for the stratification of children at increased genetic risk for type 1 diabetes, according to the results of an investigation published in Diabetes Care.
Researchers analyzed whether changes in miRNA levels could be detected before and during islet autoimmunity in whole-blood samples from children with human leukocyte antigen (HLA)-conferred risk of type 1 diabetes in the Type 1 Diabetes Prediction and Prevention (DIPP) study (ClinicalTrials.gov Identifier: NCT03269084).
Whole-blood samples were obtained at multiple time points, and case-control matching was based on HLA-DQB1 genotype, date and location of birth, and sex.
MicroRNA sequencing was conducted on 87 longitudinal samples from 4 multiple-autoantibody-positive individuals and matched autoantibody-negative control individuals.
Differential expression between the two cohorts was tested with use of a linear mixed-effects model for each miRNA. The most significantly upregulated miRNA in patients was hsa-miR-6868-3p (P < .001), which had not been previously associated with type 1 diabetes and was upregulated before seroconversion.
The finding (P <.001) was confirmed in these and 10 additional case-control pairs with use of miRNA sequencing of 2 time points before seroconversion (miRNA-sequencing validation cohort). MicroRNA upregulation was confirmed with TaqMan quantitative, real-time polymerase chain reaction assay in samples from 29 case-control pairs, 14 of which were included in the miRNA-sequencing analysis (TaqMan validation).
A strong correlation (r=0.75) was found between the sequencing and TaqMan results for hsa-miR-6868-3p expression. The TaqMan data revealed greater hsa-miR-6868-3p expression in the multiple-autoantibody-positive individuals compared with the control individuals (P <.001) across the time points, which was comparable to the miRNA-sequencing result.
The study authors also tested whether the miRNA could distinguish the 29 multiple-autoantibody-positive individuals from control individuals before seroconversion. Changes in threshold cycle expression values calculated relative to hsa-miR-191-5p were adjusted for individual HLA type and TaqMan plates with use of a linear model. The area under the receiver operating characteristic curve was 0.76, which indicated that the miRNA may be a screening biomarker for the stratification of children at increased genetic risk for type 1 diabetes.
The miRNA is expressed in the pancreas, as well as in the blood, breast, and brain, “presenting an interesting possibility that its upregulation in blood samples of case children originates from the pancreas and circulates through blood under inflammatory conditions,” according to the researchers. “It is important to note that this miRNA may also come from blood lymphocytes, given its expression in these cells.”
The model reached a higher sensitivity of 0.86 at a specificity of 0.66, and it is not known whether combining hsa-miR-6868- 3p with other miRNAs or messenger RNAs (mRNAs) will improve the performance of the predictive model.
The sample size of 58 participants represents a limitation of this study, and the investigators advise that the findings need to be validated in whole-blood samples of an independent and preferably larger population.
“It will also be interesting to determine whether the miRNA expression correlates with the time from seroconversion to clinical disease,” stated the study authors.
Suomi T, Kalim UU, Rasool O, et al. Type 1 diabetes in children with genetic risk may be predicted very early with a blood miRNA. Diabetes Care. Published online February 8, 2022. doi:10.2337/dc21-2120