What is the role of microRNAs in social behavior?

January 3rd, 2019

image taken from ‘Biomarkers Insights-QIAGEN’

Researchers have found that a microRNA cluster which regulates the synaptic strength is basically involved in the control of social behavior in mammals.

MicroRNAs (miRNAs) belong to a class of small noncoding RNAs having a length of ∼22nt. They are involved in the regulation of gene expression at the posttranscriptional level. They perform this function either by degrading their target mRNAs and/or inhibiting their translation. Unill now, 940 members of the family were known in humans.

The researchers assume that their discovery may help them to find out new strategies to treat social deficits in neurodevelopmental disorders. For example, autism spectrum disorder(ASD) or schizophrenia. The research was published in EMBO Reports.

As we know that firstly DNA copied to make messenger RNA molecules (mRNAs) which are then translated into protein. MicroRNAs are short RNA fragments which do not code for a protein.

Basically, they function by regulating the stability or translation rate of mRNAs. Thus, they are involved in the inhibition of protein production. The microRNAs form an entirely new layer of gene regulation. This layer has only been uncovered in the past 15 years. Each microRNA targets many different mRNAs, making them perfect for organizing complex cellular processes.

The research was conducted at the University of Marburg, Germany and later on at ETH Zurich, Switzerland. The research group of Gerhard Schratt and some other laboratories exposed that a group of 38 microRNAs plays a vital role in neural development. These microRNAs were named as miR379-410.

Furthermore, numerous hints pointed to the likelihood that miR379-410 is also involved in social behavior. Researchers now studied this in more detail. They found that miR379-410 controls sociability in the brain of mice. This study describes a new vision on the molecular mechanisms behind sociability.

Outcomes of the research

The scientists first observed the mice in which functional miR379-410 complex was not present. They found that these mice were more sociable than their littermates. It indicates that miR379-410 restrict the sociability in healthy animals.

More analysis showed that neurons of mice present in the hippocampus of the brain lacking miR379-410 formed more networks. And they were more likely to convey electrical signals.

“Our study shows that miR379-410 plays a very important role in the neural circuitries development which controls social behavior,” explains Schratt.

The miR379-410 complex targets many genes at the molecular level. Most of them were known to function in regulating synaptic transmission.

Also, a small subgroup of five microRNAs from the cluster which might describe the upregulation of key synaptic proteins. These proteins are basically involved in a process called homeostatic synaptic downscaling. It is a feedback loop. This loop kicks in when the brain becomes overactive. This over-activation occurs because of too strong synaptic contacts.

Though the present study uses mice models, there are many indications which show that miR379-410 complex is also involved in the regulation of social behavior in humans.

For instance, several miR-379-410 members are dysregulated in the brain and blood of patients with neurodevelopmental disorders. It affects social behavior, like schizophrenia or autism spectrum disorder.

This study may contribute to the development of therapeutic strategies to improve social deficits in neuropsychiatric disorders in the future.

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