Multiple Sclerosis

Paige O. and Janelle H.

What is Multiple Sclerosis?

Your immune system attacks a fatty material called mylein, which covers your nerve fibers (in the CNS) for protection. Without this outer shell, your nerves become damaged and scar tissue may form.

The damage means your brain can no longer send signals through your body in the correct way. Your nerves also don’t function as normal, and cannot help you move and feel. As a result, you may have the following symptoms:

  • Trouble walking
  • Feeling tired
  • Muscle weakness or spasms
  • Blurred or double vision
  • Numbness and tingling
  • Sexual problems
  • Poor bladder or bowel control
  • Pain
  • Depression
  • Problems focusing or remembering


Often called the "Prime of Life" disease since it usually occurs between the ages of 20-40



"MS Overview and Outlook." WebMD. WebMD, n.d. Web. 13 Nov. 2015.

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Causes

Vitamin D: Researchers are not sure, but they believe vitamin D may play a role in the disease. This is because it is more common among people who live nearer to the equator.

Genes: Chromosome 6 is affected by M.S. Chromosome 6 is identified as identifying cell functions and roles.

Local and Long Distance Signaling

In both local and long-distance signaling, only specific target cells recognize and respond to a given signaling molecule.

Local signaling:


  • Paracrine signaling- A secreting cell acts on nearby target cells by discharging molecules of a local regulator into the extracellular fluid
  • Synaptic Signaling- a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell.


Long-distance signaling:


  • Hormonal signaling-specialized endocrine cells secrete hormones into body fluids, often the blood. Hormones may reach virtually all body cells.


With multiple sclerosis, the signaling with the neurons (synaptic signaling) is where the disease forms and attacks the body. Mixed up signals from the neurons can lead to numbness and tingling, or even paralysis (as seen above in the symptoms listed). These symptoms and losses can be temporary or permanent.


"Chapter 11: Cell-to-Cell Signaling." Quizlet. N.p., n.d. Web. 13 Nov. 2015.

Normal Signal Transduction Pathway vs. MS Signal Transduction Pathway

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Whats Happening

The affected nerve cells can no longer transmit signals from one area of the brain to another.


Example: This effect is similar to Christmas lights. If there is a break in the cord then the whole strand of lights will not work

Extracellular Molecules in Signal Transduction

Communication by extracellular signals usually involves six steps:

(1) synthesis

(2) release of the signaling molecule by the signaling cell;

(3) transport of the signal to the target cell;

(4) detection of the signal by a specific receptor protein;

(5) a change in cellular metabolism, function, or development triggered by the receptor-signal complex

(6) removal of the signal, which often terminates the cellular response.



In animals, signaling by extracellular, secreted molecules can be classified into three types — endocrine, paracrine, or autocrine — based on the distance over which the signal acts.



Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 20.1

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How does this effect M.S?


In M.S, the paracrine signaling is what the disease is effecting. Neuroinflammation has been hypothesized by researchers to take place in the lower locus ceruleus part of the brain. This inflammation is associated with high levels of extracellular ATP which is released from activated cells or leaks from injured or dead cells in the central nervous system. The cells involved in M.S, such as neurons and immune cells, can sense this molecule, as well as other extracellular nucleotides. When extracellular nucleotides build up apoptosis of immune cells begins.


Cieślak, Marek, Filip Kukulski, and Michał Komoszyński. "Emerging Role of Extracellular Nucleotides and Adenosine in Multiple Sclerosis."Purinergic Signalling. Springer Netherlands, n.d. Web. 13 Nov. 2015.


"Neurotransmitters in M.S." ScienceDaily. ScienceDaily, n.d. Web. 17 Nov. 2015.

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How cyclic AMP affects cellular biochemical pathwyas in MS

Cyclic AMP is well known for to decrease inflammation. It is very important to the body and helps in signal transduction and is a second messenger.
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How do Cells Receive Signals?

Once a receptor protein receives a signal, it undergoes a conformational change, which in turn launches a series of biochemical reactions within the cell. These intracellular signaling pathways typically amplify the message. Activation of receptors can trigger the synthesis of small molecules called second messengers, which initiate and coordinate intracellular signaling pathways (a common second messenger is cAMP). These cAMP molecules activate the enzyme protein kinase A, which then phosphorylates multiple protein substrates by attaching phosphate groups to them. Each step in the cascade further amplifies the initial signal, and the phosphorylation reactions mediate both short and long-term responses in the cell. The reaction stops once it is degraded by the enzyme phosphodiesterase.



"Cell Signaling." Nature.com. Nature Publishing Group, n.d. Web. 17 Nov. 2015.

Where does it go Wrong in M.S?

As stated above, the signaling in a cell effected with M.S goes array when the mylein is eaten away by your immune system, and the nerve cell has an opening in it. This redirects the signal from the nerve and into empty space surrounding the nerve cell, meaning the signal never reaches the target cell.