Biomarker selection
We screened three biomarkers of metabolic syndrome-related diseases respectively.

Search strategy

        Literature searches were conducted in PubMed,EMBASE,Cochrane,Web of Science and Ovid from 1980 to April 2023.we performed the following search:"micro RNA"OR "miRNA"AND ("NAFLA"OR "non-alco- holic fatty liver disease")OR ("DM"OR 'diabetes mellitus")OR ("depression"OR *depressive disorder)AND "biomarker".

Inclusion criteria

(1).   

The study participants were patients diagnosed with NAFLD.DM or depression

(2).   

miRNAs are studied as diagnostic markers for diseases.

(3).   

Studies were performed in miRNAs detected in serum or plasma.

(4).   

The selected biomarkers should be easily detectable and detectable in the early stages of the dis- ease.preferably at concentrations that change with the disease process1-5.

Results

        We first searched in each database using keywords,removing duplicates that did not meet the inclusion criteria by reading the titles or abstracts,and then reading the articles in full to exclude studies whose re- sults were not statistically significant.The final numbers of included studies related to the three diseases of NAFLD,DM and depression were 9.13 and 5.respectively.
        To screen for the most appropriate biomarkers,we made tables of the characteristics of the miRNAs in- cluded in the study to facilitate comparison.The table includes6-9:
the names of the miRNAs
Roles in the metabolic syndrome
Region of the subject population
Biological material (plasma,serum)
Assay method (qRT-PCR)
Reference values or fold changes in concentration of miRNA as a biomarker in controls and patients10-13 Testing difficulty level
Finally,three selected miRNA were hsa-miR-34a in NAFLD,hsa-miR-155 in DM and hsa-miR-1281 in de- pression.

Databases for miRNAs

        The database was searched for more information about the selected miRNAs,involving nucleotide num- bers,target genes.functions,sequences,and their expression in cell lines14.The databases of choice in- clude miRBase.TarBase.GeneCards,RefSeg.DIANA-LncBase and RNAcentral.The results show that the three miRNAs we screened do not target human genes and meet the whitelisting requirements of iGEM.
Bioinformatics Analysis
        The existing literature data and CEO database were used for biogenic analysis to verify the correlation between MiRNA-34a and NAFLD.The result is shown in Fig 1.

Graph of results of bioinformatics analysis.

Scatter diagram

Area under curve

        AUC (Area Under Curve)is defined as the area surrounding the axis under the ROC curve,and obviously the value of this area cannot be greater than 115.Since the ROC curve is generally above the line y=x,the AUC value ranges between 0.5 and 1.The closer the AUC is to 1.0,the higher the authenticity of the detec- tion method.
The above results prove that MiRNA-34a can be used as a biomarker for the detection of NAFLD.and our experiment has certain feasibility and accuracy.
https://github.com/xyf1041632550/AFMU-China-Bioinformatics Analysis Click here for R scripts in Github.
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