Ye Wang

Hello I am Ye Wang, presently a PhD student in Gunilla Westermark’s group. I have a background in clinical medicine and my bachelor degree is from Capital Medical University, Beijing, China. I came to Uppsala University in 2011 to pursue my master degree in biomedicine. I did my master’s degree project in the amyloid field and continued my PhD study on the same topic.

 

Both Type 2 Diabetes (T2D) and Alzheimer’s disease (AD) are localized forms of amyloidosis, and epidemiological studies show that individuals with T2D have a 50-150% increased risk of developing AD. My first project focuses on the direct interaction between the two amyloidogenic peptides—islet amyloid polypeptide (IAPP), which deposits in islets of Langerhans in patients with T2D and beta amyloid (Aβ), which deposits in brains of patients with AD. I have established a cell-based assay for studying IAPP and Aβ interaction and subsequent cellular effects by using Bimolecular Fluorescence Complementation (BiFC). Specific interaction between IAPP and Aβ are visualized using BiFC in living cells 24h after transfection, and a parallel orientation of peptides is preferred. Transmission electron microscope analysis reveals fibrils with amyloid-like appearance, and an increase in both lysosomal and mitochondrial area are observed.

 

Fig. 1, In BiFC system, each peptide is connected to the N- or C-terminal half of YFP via a linker. When two peptides interact, the YFP parts are brought together allowing YFP to reconstitute, anvent that can be detected as a fluorescent signal. Peptides can interact in both parallel (left) and anti-parallel (right) manners. PPI: protein-protein interaction. YFP: yellow fluorescent protein.
 

Fig. 2, HEK293 cells transfected with IAPP-linker-YN173 and IAPP-linker-YC155 (left), IAPP-linker-YN173 and Aβ-linker-YC155 (middle) and Aβ-linker-YN173 and Aβ-linker-YC155 (right). In the right panel Aβ-expression results in the appearance of single or multiple dots in transfected cells different from the diffuse cytoplasmic fluorescence seen in the left panel. Scale bars: 20µm.

There is a need for accurately detection of amyloid but also monitoring the process of amyloid formation under physiological conditions. Therefore, a second project of mine is to evaluate Luminescent Conjugated Oligothiophenes (LCOs) in detecting islet amyloid and islet amyloid formation (this work is in collaboration with Professor Peter Nilsson’s group at Linköping University). LCOs are a group of molecules containing different length of thiophene rings and sidechains. Upon binding to protein aggregates, the conformation of the backbone is dictated by the protein, which results in conformation-sensitive spectral signatures from LCOs. So far, I have tested 4 different types of LCOs, regarding their toxicity, sensitivity and specificity in detecting islet amyloid and the ability of LCOs to monitor real-time amyloid formation. My work has resulted in the identification of a promising LCO—pFTAA-CN, to be used for detection of islet amyloid under a variety of conditions e.g. during culture of isolated human islets, unfixed frozen islets and formalin-fixed islets. With further studies I will use pFTAA-CN to monitor the inhibitory effect of small molecules on amyloid formation in cultured human islets.

Fig. 3, Islet amyloid detected by Congo red (left), Thioflavin S (middle) and the LCO pFTAA-CN (right) in formalin-fixed consecutive section form human pancreas. pFTAA-CN exhibits the same amyloid pattern as Congo red and Thioflavin S. Scale bars: 100µm.


Recent studies suggested that there is an interaction between IAPP and alpha synuclein (α-syn), another amyloid protein which deposits in brains of patients with Parkinson’s disease (PD). At present, I am working on characterization of synuclein expression in isolated human islets and possible interaction between IAPP and α-syn.

Fig. 4, In formalin-fixed human islets, α-synuclein (red) is co-localized with insulin (green). From left to right: Red: α-synuclein, Green: insulin, Blue: DAPI, Tricolor: merged. Scale bars: 50µm.

Main skills used in my research

I am familiar with most techniques in cell and molecular biology - plasmid construction, protein expression and purification, FRET, ELISA, qRT-PCR, WB, IHC, cell culture, flow cytometry etc. I am skilled in histology and histopathology and use polarized light microscope, confocal microscope and transmission electron microscope for my experiments. Part of my research also includes using small animal models - Drosophila melanogaster and Caenorhabditis elegans.


For further information about this research project please contact Ye Wan