Nanoscale Structural Comparison of Fibrillin-1 Microfibrils Isolated from Marfan and Non-Marfan Syndrome Human Aorta

Figures

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  Figure 1. Schematic domain structure of fibrillin-1. The two fibrillin-1 gene (FBN1) mutations concerned in the current work are indicated with arrows (#1MFS, Marfan patient 1; #2MFS, Marfan patient 2). RGD, arginine-glycine-aspartic acid cell binding site.

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  Figure 2. Atomic force microscopy of fibrillin microfibrils purified from MFS and non-MFS human aortic tissues; #4 is a control sample, and #1MFS and #2MFS refer to the respective mutations. The microfibrils displayed a conserved morphology but were of various lengths irrespective of the sample of origin. A characteristic “beads-on-a-string” aspect dominates the topography, in which the beads are interconnected by filamentous interbeads. As pictured in the inset, the interbeads were often visible in the form of two or three filamentous arms connecting the beads. Additionally, lateral filaments (arms) emerging from the surface of some of the beads could also be observed (yellow arrows).

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  Figure 3. Analysis of the topographical features of fibrillin-1 microfibrils. The left side column shows the statistical comparison of the MFS and non-MFS populations in terms of bead height (a), length (c), and width (e), as well as interbead height (g). The right side column shows the statistical comparison of individual samples in terms of bead height (b), length (d), and width (f), as well as mean interbead height (h). The horizontal black bars mark the statistically significant differences between sample means (except for bead length and width, where each of the MFS samples generated statistically significant differences with each of the non-MFS samples).

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  Figure 4. Comparison of interbead periodicity in MFS and non-MFS fibrillin microfibrils. (a) Statistical comparison of pooled periodicity values in the two populations. (b) Comparison of mean periodicities between individual samples. The horizontal lines indicate pairs of samples displaying statistical differences. (c) Distribution of periodicity in the two studied groups.

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  Figure 5. Schematic representation of the sections used for measuring the structural parameters of fibrillin-1 microfibrils. Considering the arbitrary disposition of the microfibrillar assemblies, bead length (longitudinal section, red) and width (transversal section, yellow) were assessed in respect to the median axis of the respective microfibril.