The Selection of RNA Aptamers against S100 Calcium Binding Protein B for Inhibition of Inflammatory Cytokines in Alzheimer’s.

The full proposal can be seen here

Progress Report 1 can be seen here
Progress Report 2 can be seen here

Final Report can be seen here

S100B is a calcium binding protein produced mainly by glial cells in the Central Nervous System (1). As calcium binds to the EF-hands of the protein, S100B undergoes different conformational changes, allowing the protein to bind to several other molecules in the body, making it a multi-functional target (2). Because of the variety of binding capabilities for S100B, these proteins participate in several neurological diseases including Alzheimer’s, epilepsy, schizophrenia, Down’s syndrome, and melanoma (3).

Alzheimer’s disease (AD) is the predominant form of dementia, where patients suffer from a decline of cognitive functions such as language, personality, and memory (4). S100B plays a substantial role in AD as suggested by the elevated levels of the protein in the brain or CNS after diagnosis. S100B can act intracellularly or can be secreted into the extracellular space of glial cells and act as a cytokine, which binds to nearby cells via receptors (5). S100B activates the Receptor for Advanced Glycation Endproducts (RAGE), an immunoglobulin-like cell surface receptor , and in turn, triggers NF-kB and MEK signaling pathways (6). Although nanomolar concentrations of S100B can have trophic and neuroprotective effects, any over expression of the S100B protein can lead to neuroinflammation, neuronal dysfunction, and cell apoptosis that contributes to the degenerative affects of Alzheimer’s (4).
Figure 1: Signal transduction pathway between S100B/RAGE/ and NF-ĸB.
RAGE is activated initially by S100B, that starts a positive feedback loop to continually trigger S100B proteins that activate NF-ĸB gene transcription which release inflammatory cytokines.

Although elevated levels of S100B can indicate brain trauma and Alzheimer’s, no preventative measures to actually delay the onset of neurological damage have been developed. An aptamer is a sequence of nucleic acid that binds specifically to target molecules, primarily proteins (7). An aptamer selected for S100B protein can potentially be used as both a therapeutic and diagnostic tool in combating Alzheimer’s.

Specific Aim 1: Selection of RNA aptamer against S100B protein High concentrations of S100B in the brain and CNS lead to over stimulation of RAGE leading to neurological damage. The selection of an aptamer for S100B that inhibits binding, either directly or allosterically, to the V domain of RAGE will impede further signal transduction pathways that hinder neurological function. The inhibition of the S100B/RAGE interaction would provide a therapeutic method to slow down the devastating effects of Alsheimer’s.

References
1. Zhang, X.Y., et. Al. (2010) “Increased Serum S100B in never-medicated and medicated Schizophrenic patients.” Journal of Psychiatric Research 10:1-5.

2. Razvanpour, A., and Shaw, G. (2009) “Unique S100 Target protein interactions.” Gen. Phsyiol. Biophys. 28: 39-46.

3. http://en.wikipedia.org/wiki/S100B

4. Leclerc,E., et. al. (2010) “The S100B/RAGE Axis in Alzheimer’s Disease.” Cardiovasc. Psychiatry Neurol. P. 1-20.

5. Huttunen, H. et al. (2000) “Coregulation of Neurite Outgrowth and cell survival by Amphoterin and S100 proteins through Receptor for Advanced Glycation Endproducts (RAGE) Activation.” Journal of Biological Chemistry. 275(51): 40096-40105.

6. Sorci, G. et al. (2003) “S100B inhibits Myogenic differentiation and Myotube formation in a RAGE-independent manner.” Molecular and Cellular Biology. 23(14): 4870-4881.

7. http://en.wikipedia.org/wiki/aptamer

Image: Leclerc,E., et. al. (2010) “The S100B/RAGE Axis in Alzheimer’s Disease.” Cardiovasc. Psychiatry Neurol. P. 1-20.

S100B RayBiotech, Inc.
$149/100ug
HIS tag
PBS buffer

10 comments:

Amanda C. Romero said...

I'm very excited for your target Ewa!! Imagine the possibilities, oh baby!!

Nia_Fernandez said...

I think saying the concentrations are high after diagnoses can be misleading!

It is a very stream lined abstract and is very easy to follow!

Austin Rezigh said...

Great project!Alzheimer's is such a powerful disease and aptamers present a clear possibilty for it's hindrance.

"As calcium binds to the EF-hands of the protein, S100B undergoes different conformational changes, allowing the protein to bind to several other molecules in the body, making it a multi-functional target (2)."

It seems possible that an aptamer could be able to alter S100B protein strucutre in a way similar to it's multiple conformations. If the corresponding substrate could bind, even loosely, could that pose a problem? (I may have completely understood what you said)Or the aptamer could yield an entirely new conformation that could serve a therapeutic function for multiple diseases.

If a successful selection occurred, how would you go about making the aptamer a diagnositc tool?

Great job with writing the abstract. I was able to follow along quite easily...I think lol.

Mayank Aranke said...

Sounds like exciting target! I'm also working with Alzheimer's, but with a target more exclusive to AD. I really like the multi-faceted approach of S100 though!

Brad Hall said...

Great target Ewa and good information finding it. The target is pretty cheap too from RayBiotech, Cat# 230-00002, 100ug is $149 and it is 12.5kDa.

Kamaxi Patel said...

Sounds like a really good project! I actually have the same protein as you and thought to use it as a diagnostic and therapeutic aptamer for Alzheimer's!

Emma Weiss said...

Thanks Guys!

Austin: I was thinking I would use S100B more a therapeutic agent since Kamaxi was approaching the same target from a diagnostic point of view. Hopefully an aptamer will cause a conformational change that discontinues the positive feedback loop of S100B.

Is it bad that my writing is easy to read? Should I beef up my writing? Is this abstract too simple?
THANKS FOR THE INPUT

holli.duhon said...

Good proposal. Made a few comments here.

Adelaide said...

Hello Emma I´m an Assistant Professor in Lisbon, Portugal, that is beggining to work with S100B in the context of demyelination, and I found your project really stimulating. Hence I would like to talk to you about it and possible collaborations... Just let me know if is there any way to contact you.

Best

Adelaide Fernandes

Emma Weiss said...

Hello Adelaide!

Thank you so much for the interest in my project, and I would be very happy to talk further with you about it. My email address is emweiss09@yahoo(dot)com. I look forward to hearing from you soon!