Int J Biol Sci 2012; 8(1):118-123. doi:10.7150/ijbs.8.118

Research Paper

Immune-related MicroRNAs are Abundant in Breast Milk Exosomes

Qi Zhou1*✉, Mingzhou Li2*, Xiaoyan Wang2, Qingzhi Li2, Tao Wang2, Qi Zhu3, Xiaochuan Zhou3, Xin Wang4, Xiaolian Gao4, Xuewei Li2 ✉

1. Department of Nursing, Ya'an Vocational College, Ya'an, Sichuan, China;
2. Institute of Animal Genetics & Breeding, College of Animal Science & Technology, Sichuan Agricultural University, Ya'an, Sichuan, China;
3. LC Sciences, Houston, Texas, USA;
4. Department of Biology & Biochemistry, University of Houston, Houston, Texas, USA.
* These authors contributed equally to this work.


Breast milk is a complex liquid rich in immunological components that affect the development of the infant's immune system. Exosomes are membranous vesicles of endocytic origin that are found in various body fluids and that can mediate intercellular communication. MicroRNAs (miRNAs), a well-defined group of non-coding small RNAs, are packaged inside exosomes in human breast milk. Here, we identified 602 unique miRNAs originating from 452 miRNA precursors (pre-miRNAs) in human breast milk exosomes using deep sequencing technology. We found that, out of 87 well-characterized immune-related pre-miRNAs, 59 (67.82%) are presented and enriched in breast milk exosomes (P < 10-16, χ2 test). In addition, compared with exogenous synthetic miRNAs, these endogenous immune-related miRNAs are more resistant to relatively harsh conditions. It is, therefore, tempting to speculate that these exosomal miRNAs are transferred from the mother's milk to the infant via the digestive tract, and that they play a critical role in the development of the infant immune system.

Keywords: breast milk, exosome, immune-related miRNAs, deep sequencing.

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How to cite this article:
Zhou Q, Li M, Wang X, Li Q, Wang T, Zhu Q, Zhou X, Wang X, Gao X, Li X. Immune-related MicroRNAs are Abundant in Breast Milk Exosomes. Int J Biol Sci 2012; 8(1):118-123. doi:10.7150/ijbs.8.118. Available from