Role of Vitronectin in Adhesion and Migration of Human Mesenchymal Stem Cells under Different Physiological Stress Conditions

Sen, Ankita (2023) Role of Vitronectin in Adhesion and Migration of Human Mesenchymal Stem Cells under Different Physiological Stress Conditions. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Ankita Sen (17RS015)) 17RS015.pdf - Submitted Version Restricted to Repository staff only Download (6MB)

Abstract

Mesenchymal stem cell (MSC) therapy has been widely investigated and accepted for the treatment of inflammatory and auto-immune diseases. However, in clinical trials, MSC-based therapies have had limited success. One of the primary reasons for the compromised efficacy of MSCs has been the adverse microenvironmental conditions like nutrient deprivation, ischemia, hypoxia, and inflammatory condition, at the target site, which affect their migration, engraftment, and viability post-transplantation. Hence, to attain improved efficacy assessing the impact of such stress conditions on the adhesion and migration of MSCs and identifying the key molecular players that affect these properties assumes paramount importance. Our study evaluated the effect of different physiological stress conditions like febrile temperature (40°C), serum starvation, and hypoxia (2% O₂) on the morphology, adhesion, and migration of human umbilical cord-derived Wharton’s jelly MSCs (WJ-MSCs). Exposure to 40°C and serum starvation stress led to an increase in the cell spread area and cellular adhesion while reducing the migration of WJ-MSCs. Corresponding to these changes, vitronectin (VTN), an ECM glycoprotein, was found to be upregulated under 40°C and serum starvation stress. siRNA-mediated knockdown of VTN under 40°C and serum starvation stress established the possible role of VTN in regulating the morphology, adhesion, and migration properties of WJ-MSCs under these stress conditions. Inhibition of different signalling pathways by small molecule inhibitors or siRNA treatment highlighted NF-κβ as a positive regulator of VTN expression, while the ERK pathway regulated it negatively under these conditions. Assessing the adhesion and migration properties of WJ-MSCs by inhibiting these signalling pathways further confirmed the correlation between VTN expression levels and alteration in cell adhesion and migration parameters. Furthermore, the study under serum starvation highlighted that VTN regulated focal adhesion (FA) formation by inducing the phosphorylation of myosin light chain (MLC). An increase in MLC phosphorylation under serum starvation promoted the formation of a large number of FAs, which were responsible for the observed increase in adhesion, along with reduced migration of serum-starved WJ-MSCs. Overall, VTN emerged as a key player in regulating the adhesion and migration of WJ-MSCs under certain physiological stress conditions.

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