The Effects of Obesity on Protein Corona Formation

Sammanfattning

Obesity is a disease that has experienced a significant world wide increase over the past decades, sometimes even being referred to as an epidemic. And while there are many serious and well known effects caused by obesity, there could be even more that we don’t yet know about. This experiment intends to study the change between protein corona formation around lipid nanoparticles incubated in plasma form a control group and obese group. The plasma samples came from rats and were collected and given to us by Novo Nordisk. Lipid nanoparticles were incubated in pooled plasma from several individuals for each group, allowing a protein corona to form. The samples were then separated, analysed, and fractioned using an AF4 setup with a multiangle light scattering detector, differential refractive index detector, and UV detector. The relevant fractions from each injection were collected and prepared for mass spectrometry. Novo Nordisk then collected the samples and analysed them using liquid chromatography coupled with tandem mass spectrometry. The protein analysis mainly looked into the change in protein corona presence of apolipoproteins and certain immunoglobulin related proteins. Most apolipoproteins displayed an increased presence in the protein corona of particles incubated in plasma from the obese group, with the highest increase being in apolipoprotein C-IV with 85,34%. Apolipoprotein C-I did show a higher increase with 304,92%, but due to reproducibility problems combined with being such an extreme number, it was disregarded. Apolipoprotein E which is known to make lipid nanoparticle drugs accumulate in the liver also showed an increase of 6,95%. There was also a large decrease shown for the polymeric immunoglobulin receptor, with a protein corona presence 41,88% lower for the obese group as compared to the control group. While there were some interesting and promising results, the data did overall suffer from reproducibility issues most likely due to a limited sample size, as there were only two replicates for each group. Future work should thus firstly focus on increasing the amount of data for each group in order to produce more conclusive results before focusing on other aspects.