ORCID

https://orcid.org/

0000-0002-1719-8354

Date of Award

Winter 1-5-2022

Author's School

McKelvey School of Engineering

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Master of Science (MS)

Degree Type

Thesis

Abstract

Actin stress fibers are abundant in cultured cells, but little is known about them in vivo. In podocytes, much evidence suggests that mechanobiological mechanisms underlie injury, with structural changes to actin stress fibers potentially responsible for pathological changes to cell morphology. However, this hypothesis is difficult to rigorously test in vivo due to challenges with visualization. This thesis presents the first visualization technique capable of resolving the three-dimensional (3D) cytoskeletal network in podocytes in detail while definitively identifying the proteins that comprise this network. Images acquired using membrane-extraction and focused ion beam scanning electron microscopy (FIB-SEM) were assembled and interpreted using machine learning image segmentation. Using isolated mouse glomeruli from healthy animals, we observed actin cables and intermediate filaments linking the interdigitated podocyte foot processes to newly described contractile actin structures located at the periphery of the cell body. Actin cables within foot processes formed a continuous, mesh-like, electron dense sheet that incorporated the slit diaphragms. Our new technique revealed, for the first time, the detailed 3D organization of actin networks in healthy podocytes. Our data are in agreement with the gel compression hypothesis regarding the glomerular filtration barrier and provide insight into how podocytes respond to mechanical cues from their surrounding environment.

Language

English (en)

Committee Members

Guy Genin Hani Suleiman Amit Pathak

Included in

Engineering Commons

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