STARTING AT THE BRAIN CELLS TO UNDERSTAND OBESITY

Moving from the fourth floor to the sixth floor of the IMM marks more than just an office change for Qingchun Tong, PhD, Professor and Associate Director of the Center for Neuroimmunology and Glial Biology. The shift signals a novel research focus as Tong joins the growing new center. “I have been wanting to study neuroimmunology and its relationship to body weight regulation and appetite for a long time,” he said, noting that he joined the IMM faculty in 2009 as part of the Center for Metabolic and Degenerative Diseases. As part of the new center, he will be able to forge innovative collaborations as he develops this line of research.

Investigating the brain’s immune response to diet intake, appetite regulation, and body weight changes, Tong specifically focuses interactions between neurons and nonneuronal cells, such as microglia and astrocytes. His work looks to trace astrocytes – star-shaped glial cells that comprise the majority of cells in the central nervous system – as they come into contact with neurons – known as the information messengers of the nervous system.  “We will have the ability to change and manipulate the function of astrocytes to see how they relate to neural function in terms of appetite and body weight regulation,” explained Tong, holder of the Cullen Chair in Molecular Medicine and Hans J. Müller- Eberhard, MD, PhD and Irma Gigli, MD, Distinguished Chair in Immunology.

Tong, an adjunct faculty member in the McGovern Department of Neurobiology and Anatomy, also is looking to identify key changes in the interaction between various neuronal groups or between neurons and astrocytes with nutritional or body weight changes. “We’re trying to figure out the players that mediate physical and signal interactions between neurons and astrocytes,” he explained, adding that mapping these neural circuits could be key to understanding obesity development.

The lab employs novel tracing, RNA sequencing, and imaging techniques to target glial cells and neurons under the context of normal and various stressful and disease states to understand their specific functions in normal and metabolically challenged conditions.  The role of sensory cues also is an important part of Tong’s obesity research. Environmental impacts such as bright lights and loud noises threaten animals, preventing them from looking for food.  “We are looking for key brain neurons that are a part of that decision-making process to help us as humans combat two extremely different conditions – obesity and anorexia,” he said, adding that they are trying to identify a brain region that can explain these two drastically different phenotypes.

The lab has made major advances in understanding leptin resistance – a hormone that reduces obesity. “In terms of impact, our research on obesity is far more than other conditions because we have such a large population with obesity and overweight, and obesity is a contributing factor for many other diseases,” he said.

In addition to direct contributions of brain neurons to metabolic diseases, Tong is looking at their role in affecting emotional states, such as the relationship between chronic stress and obesity development.