What Is the Astrocyte?

Astroglia is the most widely distributed type of cell in the mammalian brain, and it is also the largest in glial cells. The classic metal immersion technique (silver staining) shows that this type of glial cells are star-shaped, emitting many long and branched protrusions from the cell body, stretching and filling between the cell body of the nerve cell and its processes, supporting and separating the nerve cells. Role. ^[1]

Between adjacent astrocytes and between adjacent foot plates

The functions of astrocytes are:

(1) Potassium ion space buffer. Astrocytes have a spatial buffering effect on extracellular potassium ions and can maintain ion balance around neurons. When neurons generate action potentials, potassium ions flow out of intracellular neurons, and the potassium concentration in the synaptic space temporarily rises. Astrocytes can take up some potassium ions through potassium channels on the membrane and pass astrocytes. The gap connection between them transfers potassium ions to adjacent astrocytes, maintaining the proper concentration of potassium ions near the neurons. ^[3]

In December 2011, Professor Zhang Suchun, a Yangtze River scholar and well-known stem cell expert in the Department of Anatomy and Histology and Embryology of Shanghai Medical College of Fudan University, collaborated with the University of Wisconsin-Madison for more than 5 years. Recently, it was the first successful study in a stem cell study. Using human pluripotent stem cells to differentiate and generate astrocytes, this result has important application value for brain tissue, brain organ regeneration, repair and treatment of brain diseases. The research results were published in the internationally renowned academic journal Nature · Biotechnology. ^[4]

Human pluripotent stem cells can be differentiated into any cells in the body, and then can form various tissues and organs in the body. It is the focus and focus of current stem cell research. Astrocytes are the most abundant and important functions of glial cells Damaged cells, such as the blood-brain barrier, are damaged, and astrocytes can play a role in repair and regeneration. Although in recent years, scientists have successfully cultured and differentiated a variety of somatic cells and different tissues such as cardiac muscle, nerves, pancreas, bone, etc. using pluripotent stem cells. However, how can human embryo pluripotent stem cells be "successfully induced" to differentiate into brain repair Astrocytes, which play an important role in the treatment of brain, regeneration and brain diseases, have always been an elusive "dream" for researchers. ^[4]

In a long-term study, the research team led by Professor Zhang Suchun differentiated human pluripotent stem cells into approximately uniform immature astrocyte populations. The results revealed and confirmed that these cells had similar gene expression and glutamine as those of primary glial cells. Functional properties such as acid uptake and promotion of synapse generation. Zhang Suchun's team transplanted these cells into the mouse brain, and found that these cells were connected to brain capillaries and turned into mature astrocytes. "Nature · Biotechnology" believes that this breakthrough achievement provides a new cell model for studying brain development and function, understanding the role of glial cells in the disease process, and will promote the development of new strategies for the treatment of neurological diseases. ^[4]