MicroRNAs play a key role in regulating the function of immune cells

According to a recent study published in the Cell Reports journal, the ability of the immune system to mobilize specialized cells to fight against infections depends partly on small molecules, known as microRNAs. MicroRNAs serve as a release for the “brakes” that maintain the cells in inactive states, until required.

Connie Krawczyk, PhD. Image Credit: Van Andel Institute.

These small microRNAs have an important role in balancing the on/off state of the immune system. Our findings reveal new insights into the nuts and bolts of immune function and add to a growing body of knowledge that could one day be leveraged to optimize vaccines or immunotherapies for a number of diseases.”

Connie Krawczyk, PhD, Study Senior Author and Associate Professor, Metabolic and Nutritional Programming Group, Van Andel Institute

The immune responses of the human body are governed by many different cells and components. Each of these cells and components plays its role in warding off pathogens, clearing out atypical cells, such as cancer, and jump-starting the process of healing. When there is no threat, the immune cells should be ready, but remain in a “resting” state.

MicroRNAs play a role in this complex defense system. These tiny RNA molecules can quickly control gene expression, which consequently has a direct impact on the immune responses of the human body.

Krawczyk and her collaborators observed that one microRNA can account for controlling numerous genes in a single type of cell while having minimal impact on another type of cell, an adaptation that perfects the immune response and makes sure that the right immune cells are deployed at the right time.

For instance, a specific microRNA known as microRNA-9 helps establish when dendritic cells, which trigger immune responses, are inactive or active by controlling the “brakes” that help maintain the cells in their inactive states.

When the microRNA-9 is called to action, it releases the “brake” and permits access to the genes required to bring the cells to action.

Our study really gets into the weeds of how the immune system works and how it is able to be so specific in its response to pathogens. The findings add to the growing evidence backing the therapeutic potential of microRNAs.”

Connie Krawczyk, PhD, Study Senior Author and Associate Professor, Metabolic and Nutritional Programming group, Van Andel Institute