coagulation questions (alzheimers related)!!

[deleted-759069]

I'm just in the stage of background research, so I'm not sure about what I would hope my project to be specifically, but I do know the premise I hope for is to disaggregate the tau and fibrin reaction that occurs in Alzheimer's disease. The rationals for this are many NCBI studies reporting that a decrease in fibrin amount increases cognitive ability in Alzheimers patients, nature immunology reports studying that the abnormal activation of immune cells contributes to oxidative stress, and the underlying constant that blood-brain barrier leakages are much more common in early-onset patients and contributes to the tau/fibrin compounds.
Of course, for this, I need to think about the coagulation cascade and which model may be best suited for this. (I have some quite dumb questions on these topics that seem as if I could look up papers or even just google them, but really it leads me into many confusing, different results, so this is easier)

what organism to use as a model

I would either use jackson lab htau mice or attempt using aplysias. The main negatives of htau mice are the cost and regulations (there's a high chance to FTQ), but the blood-brain barrier will already have leakage and tau/fibrin compounds which makes it a much more reliable model. The negatives of aplysias are all the things in the air even after reading many, many papers. I don't know how different their blood clotting system is to ours and I'm not sure if they even produce tau... many days and I still can't find these out.
- if one would recommend me a better model, provide precautious measures for the mice (weight cant decrease <5% and none can die), or give me more information about aplysias I would be so grateful

Coagulation

I understand human coagulation but I'm wondering if this system has the same processes in the blood-brain barrier when compared to other regions of our body or if there are slight differences in perhaps the initiator of the cascade. I'm also not certain the differences between blood clotting between mice, aplysias, and humans. Finally, are there any pertinent differences between the intrinsic and extrinsic pathways?
- I'm wondering the differences between human coagulation in the blood-brain barrier vs. the rest of the body, the difference between intrinsic/extrinsic pathways, and the main comparisons between blood clotting in mice, aplysias, and humans.

I know I may have overloaded on the questions, so, if you can only answer one, please still reply! Or, if it saves you time, feel free to just link to a study/paper I havent seen yet! Thank you!

[elisenguyenle]

Hi there,

Great questions! I am giving some references that help to answer your questions.

Model:
Here is a database to search about the suitable mice/rat models used in Alzheimer's Disease research:
https://www.alzforum.org/research-models/search
Although I could not find research on fibrin and blood clot formation of Aplysia, I also have seen some papers using Aplysia neurons to study about tau expression. (Ex: https://link.springer.com/article/10.10 ... 010-0689-7)
I would recommend you to use mice as a research model for Alzheimer's Disease.

Now, one question to ask is how tau protein interact with fibrin and interfere with the coagulation cascade. One thing to remember is while tau protein's main function is to stabilize the microtubule assembly in the cell, fibrin is associated with the blood coagulation in the blood, which is outside the cell. Here is a paper to read about blood clot and tau proteins:
https://pdfs.semanticscholar.org/797d/c ... 56839b.pdf

For experiment designs, you can refer to this research about β-amyloid peptide interacting with fibrin in the process of blot clot formation. https://www.pnas.org/content/107/50/21812

Please feel free to ask me questions.

Elise

[pharrast]

Lots of great questions, you are doing great research on your own so far! Elise has some very useful links, so definitely use them! But one thing I will say before you get too attached to a topic involving rodents is make sure you have the resources to use them! As far as I know, in the US, only people 18+ may handle live research animals, and there are so many regulations ensuring that rodents are well taken care of (proper housing, feeding, vet care) that only research universities are able to buy them. There may well be an experiment that you can do using isolated proteins, either in solutions or if you want a greater challenge in terms of acquiring materials, in some kind of cells. You could possibly get access to rodent tissue, but you would have to talk to your school about that.
https://www.aalas.org/about-aalas/posit ... -education

[deleted-759069]

thank you guys for all your help!! sadly i was researching and found someone has already disaggregated amyloid beta and fibrin, so im not sure what to do. would it be worthwhile to try and stop interaction between the 2 all together? idk.

[pharrast]

Does your assignment say you must do an experiment never performed before? That sounds pretty tough... My next concern would really be the feasibility of working with proteins like fibrin and A-Beta in isolation, as proteins are very hard to keep from breaking down in a test tube. All of your ideas so far have been very ambitious! You will make a great scientist when the resources available to you catch up with your curiosity... It may be at this point your best option to talk to your teacher about whether an interview style project could be possible. If you have access to medical doctors working on Alzheimer's in humans and/or researchers who work with animals maybe you could simply ask them some of the questions in your first post then go in deeper and ask them about the actual evidence they use to inform their ideas about the different roles the proteins you want to study play.
Sorry I cannot be more helpful

[deleted-759069]

thanks and yeah i see what you mean, i have a back up plan with an erik erikson survey that can determine the regressive developments in alzheimers patients, but i dont really want to use it. I complained to my friends also in sf and they said its very common for people to redo experiments with some changes. I'm gonna continue this idea but use a different model and make it as different as possible, it should be okay. I could use the alzheimers petri dish model, extract fibrinogen from human plasma and react it with thrombin and stain it to track it, when its added to the model it should react with amyloid beta because the dissociation constant is in nanomolar, from here im looking into ubiquitin to actually disaggregate but im not sure. im quite privileged that my friends have professor parents and im able to get some connections, so i think ill be able to work at a campus with this.

my question this time is about staining, I found a protocol to stain fibrin but would I begin this process before extracting the fibrinogen from plasma (it would be frozen and extracted by cryoprecipitation) or after? im confused on this. i could change the fibrinogen source if needed. thank you!

link of dye http://stainsfile.info/stain/hematoxyli ... allory.htm

[pharrast]

It's good that you will have a real lab and supervisors for this type of project. They will be able to tell you more about the specific methods you should use. They might have ideas about the best way to read out the results, which may or may not be through staining.
I'm not an expert on Alzheimer's, so I can't pick apart everything you said about the interactions between proteins.
If you are in a real lab, you can buy several of the proteins in your process, rather than do the isolation yourself.

Just so you're aware, volunteering time to teach you and lab space and resources, not to mention the paperwork involved in getting a minor in a lab, is a rather large ask, so reach out ASAP to get the ball rolling. You will likely have to ask several labs before you get a yes. Hopefully someone you have a connection to is in the type of lab that works with isolated proteins (not all biology labs do the same thing!)

Keep reading! It will be impressive to the scientists you want to help you if you show you have tried your best to understand the basics, but humble in admitting that you don't know what methods to use.