| Background and objective:Sarcoidosis is a disease involving some different systems.So far,the pathogenesis of sarcoidosis is not clear,and its pathological type is non-caseating epithelioid granulomatous(aggregates of lymphocytes,macrophages,epithelioid cells,and giant cells).Typical clinical features include bilateral hilar lymph node,pulmonary infiltration,and eye and skin lesions.A few patients may also have neurological and cardiac involvement.Although there are many research reports on the pathogenesis of sarcoidosis,the mechanism is not yet clear.Most patients are diagnosed to obtain pathology through exclusion and invasive procedures.Because its cause is not clear,there is still a lack of truly effective treatments.In addition,due to the lack of reliable monitoring indicators for disease progression,sarcoidosis has become a clinically difficult disease to manage.TransferRNAs(tRNAs)are classic non-codingRNA(ncRNA),which are mainly responsible for converting the genetic information of messengerRNA(mRNA)into the amino acid sequence information of new proteins.Under sex hormones,hypoxia and other stress conditions,the anticodon loop of tRNA may be spliced into half tRNA(tiRNA).The tRNA-derivedRNA fragments(tRFs)are non-coding single-strandedRNAs with a length of 14-35 nt,usually derived from the 5’end or 3’end of tRNA in a specific environment.The length and production of tRF are very similar to those of miRNA.However,the biological function of tRF is still unknown.However,important functions of tRF and tiRNA have been gradually discovered.Using transcriptomics high-throughput sequencing methods,we can find that tRF and tiRNA act as signal molecules and gene expression regulators,and have important regulatory functions in major diseases such as tumors,metabolic diseases,and neurological diseases.We plan to use transcriptomics high-throughput sequencing to detect the expression profile of sarcoidosis serum tRNA-derived fragments(tsRNA)and obtain differentially expressed tsRNA molecules,which may be a specific marker for the diagnosis of sarcoidosis.At the same time,combined with relevant clinical data,the clinical application value of tsRNA is analyzed.Then,the target mRNA of the differentially expressed tsRNA was predicted by bioinformatics technology,and the role of tsRNA and target mRNA in the occurrence and development of sarcoidosis was preliminarily discussed.Methods:Patients who were clearly diagnosed with sarcoidosis in the Department of Respiratory and Critical Care of the Second Affiliated Hospital of Jilin University from February 2019 to September 2019 were included in the sarcoidosis group,healthy subjects were the control group,and patients and healthy control groups were reserved Group serum samples.The high-throughput sequencing technology was used to analyze the tsRNA expression profile in the serum of patients with sarcoidosis and the control group,and the data was processed and analyzed by R software to obtain differentially expressed tsRNA.Real-time polymerase chain reaction(qRT-PCR)was used to verify the expression levels of differential tsRNA in sarcoidosis and control serum samples.Analyze the correlation between the above-mentioned differential tsRNA expression and clinical characteristics.At the same time,using bioinformatics to predict the target mRNA of tsRNA,perform gene function enrichment analysis on target mRNA,construct protein interaction network,and use Cytoscape software for module analysis.The receptor operating characteristic curve(ROC curve)and the interaction model between tsRNA and target genes are used to predict the Hub genes that may exist in sarcoidosis.Results:1.There are 8 subtypes and 360 differentially expressed tsRNAs detected through transcriptomics high-throughput sequencing.According to the statistics of |log FC|>1.5 and P value<0.05,there are 4 up-regulated tsRNAs and 9 down-regulated tsRNAs,two groups There were 347 tsRNAs with no significant difference.2.In the serum of patients with sarcoidosis,the expression level of tiRNA-Glu-TTC-001(0.062±0.021 vs.0.114±0.043),the expression content of tiRNA-Lys-CTT-003(1.380±0.858 vs.3.440±1.994),tRF-The expression level of Ser-TGA-007(19.280±6.812 vs.39.115±14.073)decreased.The expression level was consistent with the results of high-throughput sequencing.The expression level was decreased compared with the healthy control group,and the expression difference was statistically significant.3.Correlation analysis of the clinical characteristics of tiRNA-Glu-TTC-001,tiRNA-LysCTT-003 and tRF-Ser-TGA-007,and it is concluded that the expression levels of tiRNA-GluTTC-001 and tiRNA-Lys-CTT-003 is lower among patients older than 50 years old,and the expression levels of the two are negatively correlated with age;the expression levels of tiRNAGlu-TTC-001 and tiRNA-Lys-CTT-003 is lower in the serum of patients who has more than 1organs and systems involved,and tiRNA-Lys-CTT-003 has a linear negative correlation with the number of involved systems;tRF-Ser-TGA-007 expression in the serum of patients with hypocalcemia decreases,and tRF-Ser-TGA-007 is related to serum calcium The calcium level showed a significant linear positive correlation;the tiRNA-Lys-CTT-003 expression in serum of patients with sarcoidosis with a series of abnormal rheumatism decreased.The above differences are statistically significant.4.Perform bioinformatics analysis on tiRNA-Glu-TTC-001,tiRNA-Lys-CTT-003 and tRFSer-TGA-007,and predict its related target mRNA,tiRNA-Glu-TTC-001 can target 637 One target mRNA;tiRNA-Lys-CTT-003 can target 111 target mRNAs;tRF-Ser-TGA-007 can target 39 target mRNAs.Analysis of GO and KEGG pathways based on the predicted target genes showed that enrichment of differential tsRNA into biological pathways focused on chemokine signaling pathway,c AMP signaling pathway,c GMP-PKG signaling pathway,Retrograde endorphin signaling,Fox O signaling pathway,etc.5.Construct the PPI network of the target tsRNA target mRNA,and use Cytoscape software for visual analysis to obtain 10 Hub genes of each target tsRNA.6.Use the GEO database for serological verification of the obtained Hub genes,draw ROC curves,evaluate the diagnostic value of Hub genes for sarcoidosis,and obtain the relevant hub genes APP,PRKACB and ARRB2 related to tiRNA-Glu-TTC-001 AUC is greater than 0.7,respectively 0.707,0.728 and 0.714.The hub genes NR5A1 and MNDA associated with tRF-SerTGA-007 are greater than 0.7,0.712 and 0.726,respectively.At the same time,RNAhybrid software was used to construct a base complementary pairing model of tiRNA-Glu-TTC-001 with APP,PRKACB and ARRB2,and a base complementary pairing model of tRF-Ser-TGA-007 difference with NR5A1.Conclusion:1.There are differences in tsRNA expression profiles between sarcoidosis patients and healthy controls.2.The expression levels of tiRNA-Glu-TTC-001,tiRNA-Lys-CTT-003 and tRF-Ser-TGA-007 in the serum of sarcoidosis are decreased,and are related to clinical indicators.3.In patients with sarcoidosis,APP,PRKACB,ARRB2 and NR5A1 may participate in the occurrence and development of sarcoidosis through immune inflammation and other related pathways.They can be used as biomarkers of sarcoidosis,providing relevant research ideas for its diagnosis,treatment and prognosis. |
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