Lund University Scientists Pioneer microRNA Profiling in Immune Disease

By Malorye Allison

MicroRNAs (miRNAs) have already begun to revolutionize our understanding of oncology. Now these tiny single strands of mRNA are being studied in immune disease as well. “So far, we have identified only few genes clearly associated to polygenic immune disorders, such as asthma or diabetes,” explains Corrado Cilio, an associate professor at Lund University in Malmoe, Sweden. “It is therefore conceivable that miRNAs are involved in the fine tuning of genes controlling the molecular pathways leading to these diseases.” 

A handful of provocative studies have piqued interest in this area. “Some data from mouse work suggest that miRNA might be important in regulating the immune system,” Cilio says. For example, knockout mice whose T cell lineage cannot produce the Dicer enzyme, which is required for maturation of miRNA, also have clear defects in immune regulation. (See Cobb et al.) 

Very little research has been done on miRNA in immune diseases in humans, however. Partly, that’s because studying microRNAs can be tedious work. “That’s why I jumped on this assay,” says Cilio, speaking of Luminex’s FlexmiR Human Panel. The FlexmiR products use Exiqon A/S’s Locked Nucleic Acids (LNA) probe technology and Luminex xMAP microspheres to measure miRNA directly from patient samples in microtiter plates. The miRNA expression level is read using a Luminex analyzer. 

Using the assay, Cilio says his lab gets results “fast.” In addition, “With this assay [FlexmiR] we did not have to amplify the miRNA, so you measure exactly what you have,” he says. The assay is also convenient. “We already use the Luminex analyzer for other things already, such as measuring cytokines in samples from mice and human serum,” Cilio explains. 

The main drawback to the FlexmiR assay now is cost, according to Cilio. “As a small academic lab, we can’t afford to do a lot of samples using this system,” he says. So, just as researchers originally used gene chips to do screening studies of gene expression levels, they are using the FlexmiR Human panel to do their “fishing” and first examine a few samples for many miRNAs. Once they’ve identified some good targets, they’ll use real-time PCR in the large-scale studies. Over time, Cilio says, “The price of these kinds of assay will probably drop, just like it did with the gene chips.” 

Cilio is hopeful that just as miRNAs have opened up a whole new view of cancer, studies like his will finally illuminate the challenging and complex world of immunology. 

Additional Reference: Cuellar, TL, and McManus, MT, “MicroRNAs and Endocrine Biology,” Journal of Endocrinology (2005) 187, 327-332.

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