(K-405) Physical Properties of Hyaluronan Impact Epithelial-to-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is well studied biological process that occurs during embryonic development, wound healing, and cancer metastasis. Type II EMT occurs specifically during wound healing [1]. There are notable differences in the wound healing environment of embryos and adults. The ECM of an embryo contains more hyaluronan (HA) and type III collagen fibers. Adult wound healing ECM is characterized by having more type I collagen fibers which are thicker and more aligned, with lower levels of HA [2]. HA is an ECM component that is known to interact with collagen fibers [3]. While the effect of different collagen fiber topographies on wound healing is well understood, the effect of HA with different topographies remains unknown. To address this gap, we created synthetic matrix analogs that are capable of representing different HA topographies utilizing hyaluronan binding peptide (HABP). We further investigated the role of underlying HA topography on EMT. The results of this study will shed light on the role of HA organization on EMT during embryonic development, wound healing, and cancer metastasis.

Synthesis and Surface Modification of PCL Fibers. Polycaprolactone (PCL) fibers with diameters 0.5µm and 5µm were made through electrospinning and functionalized with HABP through aminolysis as we previously reported [4]. Fiber characterization was performed through SEM and water contact angle analysis. Cell Culture MCF-7 human breast carcinoma cells were used to study EMT. Briefly, cells were cultured in EMEM with 10% FBS and 100 U/ml Penn/Strep were grown to 80% confluency and either used in experiments or further expanded for culture maintenance. Cell Morphology. Cell morphology was analyzed through fluorescent microscopy where the nucleus and f-actin were stained. When cells are in the epithelial state they are expected to have cortical actin that can be found in the membrane cortex, and cells in the mesenchymal state have cortical actin fibers that turn into stress fibers found throughout the cell.

The nanofiber membranes were characterized with water contact angle analysis after surface treatment. Figure 1A shows the addition of the peptides makes the surface hydrophilic with HABP making the surface completely hydrophilic. Next, we added soluble HA onto the membranes to investigate the effect of HA on EMT. HA is not a component of epithelial basement membrane and is primarily present in the dermis in adult skin. Fluorescent images of epithelial cells on the different surfaces shows the addition of a peptide causes cells to take on more of a mesenchymal shape (Figure 1B). Ongoing experiments are currently focusing on understanding the role that HA topography plays on EMT by measuring the concentration of EMT markers. The results of this experiment will shed light on how topography influences the factors that trigger cells to undergo EMT. The goal of this study was to determine the effect of various hyaluronan topographies on cells during Type II EMT.

1.Blake, B., & Ozdemir, T. (2023). Developing Fibrous Biomaterials to Modulate Epithelial to Mesenchymal Transition. Cells Tissues Organs. https://doi.org/10.1159/000530712

2. Degen, K. E., & Gourdie, R. G. (2012). Embryonic wound healing: a primer for engineering novel therapies for tissue repair. Birth Defects Res C Embryo Today, 96(3), 258-270. https://doi.org/10.1002/bdrc.21019

3. Frenkel, J. S. (2014). The role of hyaluronan in wound healing. Int Wound J, 11(2), 159-163. https://doi.org/10.1111/j.1742-481X.2012.01057.x

4. Ravikrishnan, A., Ozdemir, T., Bah, M., Baskerville, K. A., Shah, S. I., Rajasekaran, A. K., & Jia, X. (2016). Regulation of Epithelial-to-Mesenchymal Transition Using Biomimetic Fibrous Scaffolds. ACS Appl Mater Interfaces, 8(28), 17915-17926. https://doi.org/10.1021/acsami.6b05646