Serum extracellular vesicular miR-21-5p is a predictor of the prognosis in idiopathic pulmonary fibrosis.
Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis. Although the median survival is 3 years, the clinical course varies to a large extent among IPF patients. To date, there has been no definitive prognostic marker. Extracellular vesicles (EVs) are known to hold nucleic acid, including microRNAs, and to regulate gene expression in the recipient cells. Moreover, EVs have been shown to express distinct surface proteins or enveloped microRNAs depending on the parent cell or pathological condition. We aimed to identify serum EV microRNAs that would be prognostic for IPF.



To determine target microRNAs in IPF, we measured serum EV microRNA expression profiles using microRNA PCR arrays in a bleomycin mouse model and validated the microRNAs in additional mice using RT-PCR. Secondly, we enrolled 41 IPF patients and conducted a 30-month prospective cohort study. Expression of serum EV miR-21-5p was normalized by dividing by the EV amount. The relative amount of EVs was measured using the ExoScreen method. We calculated the correlations between baseline serum EV miR-21-5p expression and other clinical variables. Furthermore, we determined if serum EV miR-21-5p can predict mortality during 30 months using the Cox hazard model. According to the median level, we divided the IPF patients into two groups. Then we compared the survival rate during 30 months between the two groups using the Kaplan-Meier method.



Serum EV miR-21-5p was elevated in both the acute inflammatory phase (day 7) and the chronic fibrotic phase (day 28) in the mouse model. In the clinical setting, serum EV miR-21-5p was significantly higher in IPF patients than in healthy control subjects. The baseline serum EV miR-21-5p was correlated with the rate of decline in vital capacity over 6 months. Furthermore, serum EV miR-21-5p was independently associated with mortality during the following 30 months, even after adjustment for other variables. In the survival analysis, IPF patients whose baseline serum EV miR-21-5p was high had a significantly poorer prognosis over 30 months.



Our results suggest that serum EV miR-21-5p has potential as a prognostic biomarker for IPF.
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Tomonori
T
Makiguchi
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. yamitsu@med.tohoku.ac.jp.
Mitsuhiro
M
Yamada
Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
Yusuke
Y
Yoshioka
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Hisatoshi
H
Sugiura
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Akira
A
Koarai
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Shigeki
S
Chiba
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Naoya
N
Fujino
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Yutaka
Y
Tojo
Department of Advanced Preventive Medicine for Infectious Disease and Regenerative Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
Chiharu
C
Ota
Department of Advanced Preventive Medicine for Infectious Disease and Regenerative Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
Hiroshi
H
Kubo
Department of Respiratory Medicine, Japanese Red Cross Ishinomaki Hospital, 71 Nishimichishita, Hebita-aza, Ishinomaki, 986-8522, Japan.
Seiichi
S
Kobayashi
Department of Respiratory Medicine, Japanese Red Cross Ishinomaki Hospital, 71 Nishimichishita, Hebita-aza, Ishinomaki, 986-8522, Japan.
Masaru
M
Yanai
Hikarigaoka Spellman Hospital, 6-7-1 Higashisendai, Miyagino-ku, Sendai, 983-0833, Japan.
Sanae
S
Shimura
Division of Molecular and Cellular Medicine, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
Takahiro
T
Ochiya
Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Masakazu
M
Ichinose
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D000073888:Cell-Free Nucleic Acids / Q000097:blood* / Q000235:genetics; D004195:Disease Models, Animal; D000067128:Extracellular Vesicles / Q000235:genetics / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D005819:Genetic Markers; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000097:blood* / Q000175:diagnosis / Q000235:genetics / Q000401:mortality; D053208:Kaplan-Meier Estimate; D008297:Male; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000097:blood* / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D013997:Time Factors; D015854:Up-Regulation
D000073888:Cell-Free Nucleic Acids; D005819:Genetic Markers; C524940:MIRN21 microRNA, human; C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs