X-Ray Micro- and Nanodiffraction Imaging on Human Mesenchymal Stem Cells and Differentiated Cells

Marten Bernhardt,Marius Priebe,Markus Osterhoff,Carina Wollnik,Ana Diaz,Tim Salditt,Florian Rehfeldt

doi:10.1016/j.bpj.2015.12.017

Marten Bernhardt, Marius Priebe + Show 5 more

Open Access

https://doi.org/10.1016/j.bpj.2015.12.017

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Journal: Biophysical journal	Publication Date: Feb 1, 2016
Citations: 22	License type: cc-by

Affiliation: University of Göttingen

Abstract

Adult human mesenchymal stem cells show structural rearrangements of their cytoskeletal network during mechanically induced differentiation toward various cell types. In particular, the alignment of acto-myosin fibers is cell fate-dependent and can serve as an early morphological marker of differentiation. Quantification of such nanostructures on a mesoscopic scale requires high-resolution imaging techniques. Here, we use small- angle x-ray scattering with a spot size in the micro- and submicrometer range as a high-resolution and label-free imaging technique to reveal structural details of stem cells and differentiated cell types. We include principal component analysis into an automated empirical analysis scheme that allows the local characterization of oriented structures. Results on freeze-dried samples lead to quantitative structural information for all cell lines tested: differentiated cells reveal pronounced structural orientation and a relatively intense overall diffraction signal, whereas naive human mesenchymal stem cells lack these features. Our data support the hypothesis of stem cells establishing ordered structures along their differentiation process.

Highlights

Human mesenchymal stem cells provide a source for a broad spectrum of cell types for regeneration [1,2]
We apply scanning small-angle x-ray scattering with focused beams to biological cells to probe the native electron density distribution
While the full potential of these methods will probably only unfold once suitable modeling of the local and highly anisotropic diffraction patterns becomes available, we here adopt a strategy of automatized empirical analysis of the diffraction data

Summary

Introduction

Human mesenchymal stem cells (hMSCs) provide a source for a broad spectrum of cell types for regeneration [1,2]. Besides changes in gene regulation, hMSCs reorganize their acto-myosin network during this process. These structural changes are cell fate-dependent, ranging from randomly oriented to parallel fiber bundles [4]. An intimate understanding of the structural change as a function of cell fate is essential to improve stem cell treatment—possibly without the need of external biochemical induction—and might enable new approaches in medicine [8,9]. Complementary imaging methods capable to probe the native unlabeled density distribution are needed.

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