Neurons, smarter than believed

This was published by scientists at Lund University in Sweden in an article in the journal of Nature Medicine. This pioneering discovery paves the way for future therapeutic targets for inflammatory and degenerative diseases of CNS like multiple sclerosis (MS), Alzheimer’s, and Parkinson’s.

It is generally known that motor neurons regulate basic functions like movement, learning, and memory. But Swedish scientists are now able to show that the neurons are also capable of combating CNS inflammation.

The role of neurons in the regulation of immune response in the CNS has been neglected as brain and spinal cord are well protected against immune cells surveillance by a tight barrier and because neurons do not express molecules known to be involved in immune response.

“Now, we show that motor neurons are capable of actively regulating immune response and indeed they have a central role in prevention of CNS inflammation”, says Associate Professor Shohreh Issazadeh-Navikas at Lund University.

In this report, Swedish scientists have demonstrated that neurons can transmit signals to harmful T cells (a type of white blood cells important for immune defense) in the brain. These signals cause these T cells to alter their function, transforming them from harmful to benign T cells that counteract inflammation and neuronal cell death.

Pathogenic T cells can enter the CNS because of several reasons such as during viral infection of CNS, as a result of mechanical damage to CNS or inflammatory diseases of CNS or autoimmune reactions, for example in case of MS (an inflammatory disease of CNS believed to be caused by autoimmune T cells). Inflammation is now implicated to be involved also in other neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

The impetus for this research work came from previous observations made by Shohreh Issazadeh-Navikas at the Karolinska Institute and at Harvard Medical School. There she found in different experimental conditions that neurons appeared to be able to secrete certain immunological proteins that could have potential to combat inflammations.

“These observations indicated that neurons could actually play a role in the regulation of the immune cells causing CNS inflammation. This was a new concept that had virtually been unexplored, since it was believed that neurons were mainly targets of inflammatory attack rather than active player in its regulation.”

Dedicated work by a research team under supervision of Shohreh Issazadeh-Navikas at Lund University in collaboration with Dr. Bryndis Birnir resulted in the current pioneering publication in the Nature Medicine.

According to Shohreh Issazadeh-Navikas, their findings provide new knowledge about how chronic inflammation of the brain is regulated, and it could have implications for novel therapeutic approaches of inflammatory and neurodegenerative diseases such as Alzheimer, Parkinson and MS.