Identification of cell surface markers to delineate heterogenous cell population

Decoding cellular heterogeneity is essential to understand changes in biological systems and disease mechanisms. Identifying cell surface markers can aid in resolving cellular heterogeneity and can help in diagnosis and therapeutic interventions. Conventional methods to identify cell surface markers such as transcriptome, proteome and antibody profiling have their limitations in detecting rare population. Therefore, there is an urgent need to establish an unbiased method to identify novel cell surface markers that can aid in delineating cell heterogeneity. Here, we are using planaria, Schmidtea mediterranea as a model system to establish a screening platform for cell surface marker discovery. Planaria comprises neoblasts, adult stem cells known to have distinct identities based on their gene expression. These neoblasts can be classified into clonogenic (pluripotent) stem cells, and lineage-committed progenitors. Based on radiation sensitivity, cell cycle phase, and mitochondrial content, they are further categorized into X1 and X2 populations. Currently, there is a lack of knowledge about the pluripotent and regenerative capacity of the X2 neoblasts and their sub-population.    In this AWS, I will talk about the application of yeast display library systems to screen for binders against the X2 neoblast population. The screening involves sorting live and intact X2 cells and using these cells as bait to enrich for binders. Binder clones were analyzed using flow cytometry. Selected clones are further characterized using transcriptome analysis. A fluorescence microscopy-based assay and transcriptome validation of the binder clones towards X2 cells are being established.    In summary, our approach aims to provide a more efficient means of studying neoblasts and their regenerative capacity in planarians, which can be applied to study other heterogeneous cell populations.