"Science and everyday life cannot and should not be separated."
- Rosalind Franklin
Research
Research I am currently working on or have previously completed independently and under the supervision of various principal investigators.
Master Thesis
place holder
Structural elucidation of membrane associated Protein GC-C bound to Linaclotide and Plecanatide
This thesis investigated the composition of peripheral blood mononuclear cells (PBMCs) in 52 patients with Post-COVID syndrome, focusing on the influence of age and sex on immune cell populations. Flow cytometric analysis revealed sex- and age-associated differences in specific lymphocyte subsets, monocyte counts, and the CD4+/CD8+ ratio, while correlation and regression analyses identified multiple relationships between immune cell populations. Although the absence of a healthy control group limits definitive conclusions, the findings provided valuable insights which have been accounted for in a large scale explorative post-COVID biomarker study.
This project focused on the structural characterization of the guanylyl cyclase-C (GC-C) receptor in complex with the therapeutic agonists linaclotide and plecanatide. Which are used to treat gastrointestinal disorders associated with impaired fluid and electrolyte regulation, like chronic constipation. By combining protein expression, purification, and biochemical analyses, the project aimed to investigate how differences in ligand structure influence receptor binding and activation, particularly with respect to pH-dependency. The findings contribute to a better understanding of GC-C agonist pharmacology. Unfortunately the major glycosilation of the membrane protein did not allow ice free freezing. This resulted in too little resolution to successfully elucidate the structure.
Bachelor's Thesis
Publications
The effect of peptidyl arginine deiminase 4 (PAD4) inhibition on neutrophil extracellular traps (NETs) formation in DSS-induced mouse model of experimental colitis
K Xie, T Ortiz-Cerda, BFL Wimmer, N Shiung, P Witting
Free Radical Biology and Medicine, 2023, http://dx.doi.org/10.1016/j.freeradbiomed.2023.10.114
Response to Low-density Granulocytes as Novel Biomarkers of Disease Activity in IBD
Kangzhe Xie, Tamara Ortiz Cerda, Angie Schroder, Nicolette Shiung, Bruno Lemos Wimmer,
Belal Chami, Paul K Witting
Inflammatory Bowel Diseases, Volume 29, Issue 8, August 2023, Page e32, https://doi.org/10.1093/ibd/izad133