CIRM Creativity Student Hanan Sinada’s ‘Extraordinary’ Journey as a Budding Scientist

This summer we’re sponsoring high school interns in stem cell labs throughout California as part of our annual Creativity Program. We asked those students to share their experiences through blog posts and videos.

Today, we hear from Hanan Sinada, who has been busy at the Gladstone Institutes in San Francisco.

Extraordinary. That is the word I would use to describe my time here at Gladstone. This summer I have been an intern at the Gladstone Institute of Neurology, studying microglia. The brain has two main types of cells. Those cells are neurons and glial cells. Glia makes ninety percent of the cells in your brain. Although the word “glia” is derived from the Greek word meaning “glue”, glia cells are more like the support system that surround the neurons in the brain. Many people have not heard of glial cells because they are the dark matter of the brain and not involved in synaptic transition. However, glial cells have many significant functions in the central nervous system (CNS). Their main functions are to supply oxygen and nutrients to the neurons, hold neurons in place, destroy infectious agents, eliminate dead cells, and provide insulation (myelin) to neurons.

Hanan Sinada with her mentor, Gladstone Postdoctoral Researcher Dr. Grietje Krabbe

Hanan Sinada with her mentor, Gladstone Postdoctoral Researcher Dr. Grietje Krabbe

There are three main types of glial cells: microglia, astrocytes, and oligodendrocytes. In my research we focus specifically on microglial cells. Microglia only make up 10-15 percent of the total glia population. Microglia serve as the central nervous system’s macrophages. One function of microglia is to act as antigen presenting cells. Two other roles of the microglia are phagocytosis and cytotoxicity. In cytotoxicity, microglia release cytotoxic substances such as Nitric Oxide (NO) or hydrogen peroxide (H2O2), to damage neurons that have been infected. This leads to cell death. Microglia’s main function is to maintain homeostasis. As a result, microglia are constantly scavenging for apoptotic cells, infectious agents, or any foreign material. Microglia are the main orchestrators of the inflammatory response in the central nervous system (CNS). When an injury occurs in the spinal cord or the brain, microglia release cytokines that cause inflammation in that given area.

In my research we look closely at microglia because they are related to many neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease. My lab started to question about what would happen if we annihilated all the microglia in the brain. Would it decrease the possibility of avoiding the development of those diseases? So we gave wild type mice a drug that depleted all the microglia in the brain, and surprisingly enough the microglia repopulated the brain rapidly after a couple of days. By doing immunohistochemistry and using certain markers, I was able to find where this new microglia-like cell was coming from. From previous studies we already know that this new microglia is not from the periphery. Monocytes cannot cross the blood brain barrier to replace the microglia. We believe that this new microglia is coming from progenitor cell (a type of stem cell). However, we do not know which cell type is giving rise to this new microglia population.

Before starting my internship I did not know that it was going to be the most amazing and interesting learning experience I have ever had in my life. Although every now and then I would have a science crisis, such as having to change antibody because a certain staining would not work, I am so happy and lucky to be doing this cutting edge research. Not only did I learn so much but I am proud to say that I have contributed to the future of science.