Introduction of Specific 3D Micromorphologies in Collagen Scaffolds Using Odd and Even Dicarboxylic Acids

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Introduction of Specific 3D Micromorphologies in Collagen Scaffolds Using Odd and Even Dicarboxylic Acids

The construction of scaffolds and subsequent incorporation of cells and biologics have been widely investigated to regenerate damaged tissues. Scaffolds act as a template to guide tissue formation, and their characteristics have a considerable impact on the regenerative process. Whereas many technologies exist to induce specific two-dimensional (2D) morphologies into biomaterials, the introduction of three-dimensional (3D) micromorphologies into individual pore walls of scaffolds produced from biological molecules such as collagen poses a challenge. We here report the use of dicarboxylic acids to induce specific micromorphologies in collagen scaffolds and evaluate their effect on cellular migration and differentiation. Insoluble type I collagen fibrils were suspended in monocarboxylic and dicarboxylic acids of different concentrations, and unidirectional and random pore scaffolds were constructed by freezing and lyophilization. The application of various acids and concentrations resulted in variations in 3D micromorphologies, including wall structure, wall thickness, and pore size. The use of dicarboxylic acids resulted in acid-specific micromorphologies, whereas monocarboxylic acids did not. Dicarboxylic acids with an odd or even number of C-atoms resulted in frayed/fibrillar or smooth wall structures, respectively, with varying appearances. The formation of micromorphologies was concentration-dependent. In vitro analysis indicated the cytocompatibility of scaffolds, and micromorphology-related cell behavior was indicated by enhanced myosin staining and myosin heavy chain gene expression for C2C12 myoblasts cultured on scaffolds with frayedlike micromorphologies compared to those with smooth micromorphologies. In conclusion, porous collagen scaffolds with various intrawall 3D micromorphologies can be constructed by application of dicarboxylic acids, superimposing the second level of morphology to the overall scaffold structure. Acid crystal formation is key to the specific micromorphologies observed and can be explained by the odd/even theory for dicarboxylic acids. Scaffolds with a 3D micrometer-defined topography may be used as a screening platform to select optimal substrates for the regeneration of specific tissues

An autosomal dominant neurological disorder caused by de novo variants in FAR1 resulting in uncontrolled synthesis of ether lipids

Purpose: In this study we investigate the disease etiology in 12 patients with de novo variants in FAR1 all resulting in an amino acid change at position 480 (p.Arg480Cys/His/Leu). Methods: Following next-generation sequencing and clinical phenotyping, functional characterization was performed in patients’ fibroblasts using FAR1 enzyme analysis, FAR1 immunoblotting/immunofluorescence, and lipidomics. Results: All patients had spastic paraparesis and bilateral congenital/juvenile cataracts, in most combined with speech and gross motor developmental delay and truncal hypotonia. FAR1 deficiency caused by biallelic variants results in defective ether lipid synthesis and plasmalogen deficiency. In contrast, patients’ fibroblasts with the de novo FAR1 variants showed elevated plasmalogen levels. Further functional studies in fibroblasts showed that these variants cause a disruption of the plasmalogen-dependent feedback regulation of FAR1 protein levels leading to uncontrolled ether lipid production. Conclusion: Heterozygous de novo variants affecting the Arg480 residue of FAR1 lead to an autosomal dominant disorder with a different disease mechanism than that of recessive FAR1 deficiency and a diametrically opposed biochemical phenotype. Our findings show that for patients with spastic paraparesis and bilateral cataracts, FAR1 should be considered as a candidate gene and added to gene panels for hereditary spastic paraplegia, cerebral palsy, and juvenile cataracts