Identification of plant-derived microRNAs in human kidney

Abstract

Plant-derived microRNAs (miRNAs) have been implicated as functional regulators in human diseases, although conclusive evidence of this effect remains to be reported. To examine their potential functional role, we profiled the plant-derived miRNAs in 139 blood exosome samples from renal transplantation patients and were able to identify 331 plant-derived miRNAs representing 149 families. According to their miRBase annotation, these miRNAs can be traced back to 76 plant species, most of which are foods common to the human diet (e.g., tomato, soybean, potato and rice). We also profiled 41 blood exosome samples from 22 patients with acute immune rejection (AR) of renal transplants and compared them to 21 samples from 11 patients with stable allograft function to explore possible roles of the functional plant miRNAs. We identified three plant-derived miRNAs (miR4995, miR2118/2218 and miR167) associated with allograft AR whose regulatory targets are mRNAs controlling immune response, T cell activation, and other cellular functions. miR4995 mimics were generated, transfected into HEK293T cells, and their function verified. Our findings not only demonstrate the presence of functional plant-derived miRNAs in human cells, but also provide initial evidence that these miRNAs may be involved in malfunction of renal transplantation.