Eyiyemisi Damisah, MD

“Are they secreting some sort of chemicals that help with regeneration and healing processes? It’s not understood what they do. That’s a fascinating part of the work.”

Eyiyemisi Damisah, MD, and colleagues recently published data from a study using photochemical and viral methodologies to induce death in single neurons to gain an understanding of the roles different phagocytes play in the process. They observed an orchestrated and synchronized response from the players, with each glial cell operating in a specialize role, but also uncovered an additional player in the process.

, Damisah, an assistant professor of neurosurgery at Yale School of Medicine, explained that they found that in addition to microglia and astrocytes, they observed NG2 glia in the vicinity of a dying neuron also rapidly polarize their processes toward

the cell corpse. While the role of the astrocytic and NG2 glial process polarization is not understood, they speculated that it might be an attempt to form a cell barrier.

Damisah spoke to the process that she and colleagues observed as well as the number of additional questions that were raised by their findings. 

Damisah EC, Hill RA, Rai A, et al. Astrocytes and microglia play orchestrated roles and respect phagocytic territories during neuronal corpse removal in vivo. 

. 2020;6(26):eaba3239. doi: 10.1126/sciadv.aba3239.

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The assistant professor of neurosurgery at Yale School of Medicine discussed what doors have been opened by a recent study of the cell death process she and colleagues conducted.

Eyiyemisi Damisah, MD: Additional Insights Into Cell Death

“What we’re planning on doing now is to try to understand the molecular mechanisms of that interaction between astrocytes and microglia in an aged brain compared to a young brain.”

Recently, Eyiyemisi Damisah, MD, and colleagues conducted a work using photochemical and viral methodologies to induce death in single neurons to gain an understanding of the roles that microglia and astrocytes play in the process of cell death. While they observed an orchestrated and synchronized response from the players, with each glial cell operating in a specialize role, there is still much to learn.

, Damisah, an assistant professor of neurosurgery at Yale School of Medicine, offered her insights from their observations—the first such conducted in a live mammalian brain. Additionally, she explained the questions their work has raised around the relationship of this process with aging and neurodegeneration. Specifically, she noted that it is vitally important to understand how these processes are impacted molecularly as people age.

She also spoke to the process that they utilized to induce cell death, two-photon—mediated photochemically induced apoptosis (dubbed 2Phatal), and explored how that method might be expanded to help conduct further research in this area. 

The assistant professor of neurosurgery at Yale School of Medicine discussed the work that still needs to be done to understand the role cell death process might play in neurodegeneration as the human body ages.

Eyiyemisi Damisah, MD: Understanding Aging and Cell Death

“What we observed, which was surprising, is that not only do astrocytes and microglia compete for phagocytic territories, but even amongst microglia [they compete]. If there is a dead cell in the middle and 3 different microglia interested in the cell, but only 1 will interact with the dead cell.”

A recent study conducted by Eyiyemisi Damisah, MD, assistant professor of neurosurgery, Yale School of Medicine, and colleagues, used photochemical and viral methodologies to induce death in single cells and observe the process with precise spatiotemporal resolution. All told, they attempted to better understand the role players in the removal process of cell death.

, Damisah explained what she and colleagues observed from these role players: microglia and astrocytes. Some of their observations were the first such conducted in a live mammalian brain, and the insight they gathered is the first step in better understanding a process that may have huge effects on aging and neurodegeneration.

She and colleagues saw astrocytes and microglia engaging with dying neurons in an orchestrated and synchronized fashion, with each glial cell operating in a specialize role. The astrocytes rapidly polarized and engulfed numerous small dendritic apoptotic bodies, while microglia migrated and engulfed the soma and apical dendrites.

The assistant professor of neurosurgery at Yale School of Medicine discussed the observations she and colleagues have made of the relationship between microglia and astrocytes in the cell death process.

Eyiyemisi Damisah, MD: The Relationship Between Microglia and Astrocytes

“When we think about professional phagocytes in the brain, it’s not just the microglia that are working. Astrocytes and microglia work differently and have their own ways of working, but they work together.”

, the observations suggest  that this process may be a critical one to understand as it pertains to possibly aiding in the future treatment of neurodegenerative disease. She and colleagues observed the 2 major players that work in unison, astrocytes and microglia, and assessed their roles in the removal of these particles of dead cells.

In this interview, Damisah explained the observed processes of astrocytes, which rapidly polarized and engulfed numerous small dendritic apoptotic bodies, and microglia, which migrated and engulfed the soma and apical dendrites. She also dissected what still needs to be done to understand the how this process may be explored in neurodegenerative disease.

The assistant professor of neurosurgery at Yale School of Medicine discussed the current understanding of the process of cell death in the brain, and what players are involved in the removal of dead cells.

Eyiyemisi Damisah, MD: The Cell Death Processes in the Brain

“Cell death is involved in almost everything from development to aging, so I thought it was a good way to start [this research]. What happens when a cell dies in the brain?”

Cell death has been a process long known to be ever ongoing in the body. Despite being a constant through individuals’ lives, the intricacies of the process are not totally understood. Particularly, the removal process of dead cells has not been elucidated, and the coordinated interactions and roles of phagocytes during this corpse removal process even less so.

This motivated Eyiyemisi Damisah, MD, assistant professor of neurosurgery, Yale School of Medicine, and colleagues to explore how this process unfolds by developing photochemical and viral methodologies to induce death in single cells and observe the process via intravital optical imaging. The group then used these methodologies to track multicellular phagocytic interactions with precise spatiotemporal resolution.

Ultimately, their observations suggest that a precisely composed response and cross-talk between glial cells during this removal process may be a vital part of maintaining brain homeostasis. To find out more about the assessment, 

The assistant professor of neurosurgery at Yale School of Medicine spoke to the observations she and colleagues made to better understand the process of cell death and corpse removal in the brain.

Eyiyemisi Damisah, MD

Articles

Eyiyemisi Damisah, MD: Additional Insights Into Cell Death

Eyiyemisi Damisah, MD: Understanding Aging and Cell Death

Eyiyemisi Damisah, MD: The Relationship Between Microglia and Astrocytes

Eyiyemisi Damisah, MD: The Cell Death Processes in the Brain

Eyiyemisi Damisah, MD: The Role of Astrocytes and Microglia in Cell Death

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