The NEUROTRANSMITTER dopamine has been shown, in the latest research, to play a key role in development of the sympathetic nerves of the mouse lung in early postnatal life. The researchers of the study, led by Dr Xingbin Ai of Brigham and Women’s Hospital and Massachusetts General Hospital, Massauchusetts, USA, found that this was in comparison to the neurotransmitter norepinephrine, which was associated with lung development in adult life.
Asthma affects >26 million people in the USA, 6 million of which are children. Currently, the disease can only be managed by medical treatment and environmental interventions as there is no cure. Prof Ai noted that “since asthma often starts in early childhood, we believe that the identification of disease mechanisms unique to young age will provide novel therapeutic targets for early intervention of asthma.”
Alongside these findings, the research group additionally discovered that the dopamine released by the sympathetic nerves of the lung binds to the receptors of CD4+ T helper cells. This aids the differentiation process which converts these cells into Th2 cells, which cause asthma intensifying due to lung inflammation. When mice were exposed to an allergen, it was discovered that increased Th2 inflammatory events occurred in the cell due to the dopamine-DRD4 pathway. Following this, airway hyper-responsiveness decreased, as well as mucus overproduction.
Collating these results, the main finding is that the dopamine-DRD4 pathway and CD4+ T helper cells are important drivers of allergic inflammation in early development. Dr Ai does note, however, that “it is important to emphasize that simply generically blocking the nerve-immune cell communication is not a good solution, as nerves play important roles in regulating functions of the airway, such as breathing.” The next question the researchers hope to answer is how disease progression can be prevented, as well as locating the specific signalling pathways for therapeutic targeting.