Microglia: The Robin to our Batman (the brain)

Recently in my online class, I learned about the different cells just within the CNS (Central Nervous System). For those of you thinking that we only had a one-part nervous system or just need a refresher course in biology, our nervous system consists of many parts. The main systems that we learn about in grade school are the CNS and the PNS. First, the CNS or the Central Nervous System, controls the brain and spinal cord.  Second, the Peripheral Nervous System, controls everything outside of the brain/spinal cord. The microglial cell is a part of the CNS, which I will be discussing further in this topic.

The swollen microglial cells (shown on the right) can result from a traumatic brain injury.
The swollen microglial cells (shown on the right) can result from a traumatic brain injury.
Microglia cells are non-neuronal cells that are within our brain and spinal cord. The cells act as a special immune system by protecting the brain and removing debris that has been left over by dead neurons, also known as nerve cells. Since the cells act as an immune system, they respond much like how our body responds to the flu or the common cold.

Brain Injury and Microglial Cells

For example, swelling of the brain immediately comes to my mind when a brain injury occurs. Possibilities are endless when it comes to a diagnosis, such as a concussion, stroke, encephalitis, or even something as small as a headache. Much like when you scrape your arm on something sharp, you bleed and minutes later, the platelets in your body come rushing to the rescue and create a healing, protective barrier from the outside world.

The microglia cells do the same thing! They swell up when injured to protect the brain against any foreign invaders.  Crazy? I think it’s pretty amazing!

When a person undergoes brain trauma or even the slightest of injuries to the head or spinal cord, the microglia cells are activated to respond quickly to the trauma site (Streit 2000). According to Streit and his studies, microglial cells aid the injured neurons by restoring them back to health, whereas a severely injured neuron cell will or can release a toxin to alert the MG cell to destroy it. Our bodies have a unique way in taking care of dying cells so that they can do no more harm or cause mutations.

Ending thoughts

In response to what I’ve learned in class about microglial cells and also through reading a few articles, it seems that even something as small as the MG cell, can have a huge impact on our brain and spinal cord in traumatic events. On occasion, we can lose brain cells from injuries, head-banging to our favorite rock song too hard, or dozing off to the laughing gas the dentist gives us, but we can always count on Robin (the microglia cells) to help restore or give a merciful death to our neurons, while Batman (the brain) stays focused on keeping us alive and well!

Please feel free to sound off down below in the comment section! I would love to hear your opinions/thoughts/ideas, etc.  I also found a really neat video showing how microglial cells engulf neural debris (approx. 1 min. long).

Citations:
Video: https://youtu.be/KC-iW1d1p34

Streit, Wolfgang J. (2000). Microglial Response to Brain Injury: A Brief Synopsis.        Toxicologic Pathology, 28(1), 28-30. doi: 10.1177/019262330002800104

Picture: https://www.bcw.edu/cs/groups/images/documents/images/mdaw/mday/~edisp/ucm_001511.jpg

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7 thoughts on “Microglia: The Robin to our Batman (the brain)

  1. I hope you expand on this topic in future blog posts. I would love to know more about the role of microglia in traumatic brain injury. I had a concussion several years ago and also suffered from post-concussive syndrome. I always worried about the short- and long-term effects, even though I know it’s relatively mild as far as brain injuries go. Thanks for presenting your topic is such a clear way!

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  2. What a smart move of using the Batman/Robin to the Brain/Microglia analogy; that really puts the subject into perspective quickly. I agree that it is amazing how these cells respond quickly to the trauma site to aid the injured neurons by restoring them back to health. I also thinks it’s amazing that our body has so many systems of checks and balances built into it such as your example of the microglia cells assisting the immune system. I think our body is unique for having this feature, compared to other “machines”. Most machines, such as a washing machine, or a car, would not be able to signal themselves to try to repair themselves or assist in the healing of themselves if an issue is detected. Our CNS is really amazing for having the capabilities to do this.

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  3. I feel like this really solidified microglial cells for me! It also got me thinking about cancer in the brain. I know that their is a natural inflammatory response from our immune system that comes with cancer. When you said that microglial cells act as an immune system in the CNS, I started wondering if a person with a brain tumor would have an inflammatory response cause by microglial cells. I found an piece on it that I found really interesting.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3408253/

    In the case of a glioma( tumor of astrocyte cancer), microglia are present inside of the tumor at a higher density per the grade and invasiveness of the glioma. Microglia actually encourage tumor growth in this case which I find surprising. By than I mean, I’ve always thought of cancer as unable to be fought by the immune system because the immune system does not recognize it as foreign body. So in my mind I imagine a patient with a tumor, a bit of inflammation because the immune system tries to attack it but ultimately no immune response because the immune system recognizes it to be part of the host’s genome. For someone with a glioma I was expecting there to be a bit of inflammation but not for the microglial cell to enter the tumor and contribute to its mass. That makes me think..Maybe the microglial cells DO recognize the tumor as an invasive species and try to attack it but then something goes wrong and it creates an environment conducive to the growth of the tumor.

    This seems like a unique property of the brain and specifically brain cancer. Microglial cells seem to have a different immunological response to cancer than other immune system cells in the body(at least in the case of a glioma). Pretty cool! I would love to know what your thought are on this!

    -Andrea

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    1. I’m glad you enjoyed the post! I too feel that it is extremely possible that Microglia cells contribute to many issues with our brain, whether that be brain cancer, Alzheimer’s, or even a simple headache, BUT only when triggered. The cells recognize the foreign body and have to choose between accepting the invader or phagocytosis. When the cells try to go through phagocytosis, in the case of Alzheimer’s, it actually makes the disease worse. I wonder if that could be the same with brain cancer.

      When the Microglia cells react or become inflamed from responding to the invaders and they try to remove the debris, this is causing the overall body’s immune system and the brains immune system to go into an overload “panic” system. Therefore causing the Microglia cells to engulf too much, not being able to completely digest the invader, and leaving a surplus of invaders within the CNS and brain to explore our body. On the other hand, These cells can help us in many ways, like letting us know we have a headache, which sometimes would be helpful if I didn’t know half the time.

      With Batman representing our brain, he has to remain focused and stay energized to help the body compartmentalize all our of daily thoughts, past memories, reflexes, enzymatic triggers from our organs, etc. Robin, our Microglia cells, is there to watch Batman’s back, to be there for him when he can’t be his strongest. This was really the best way I could help myself with learning this section of material. I hope it helped you!

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  4. I did my blog on traumatic brain injury, particularly the frontal lobe. The frontal lobe is responsible for so many of our basic human functions that when someone suffers damage to that area – they can completely change who they are as a person. It was interesting to learn that the microglia cells are activated to respond fast to the trauma site to help the brain begin to heal. Our brain truly is an amazing piece!

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  5. It is very interesting on how the body really does take care of all our needs. Even what seems of least importance could have a major impact on our health and even cause death.

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