Personalized Development of Antisense Oligonucleotides for Exon Skipping Restores Type XVII Collagen Expression in Junctional Epidermolysis Bullosa.

Intermediate junctional epidermolysis bullosa caused by mutations in the COL17A1 gene is characterized by the frequent development of blisters and erosions on the skin and mucous membranes. The rarity of the disease and the heterogeneity of the underlying mutations renders therapy developments challenging. However, the high number of short in-frame exons facilitates the use of antisense oligonucleotides (AON) to restore collagen 17 (C17) expression by inducing exon skipping. In a personalized approach, we designed and tested three AONs in combination with a cationic liposomal carrier for their ability to induce skipping of COL17A1 exon 7 in 2D culture and in 3D skin equivalents. We show that AON-induced exon skipping excludes the targeted exon from pre-mRNA processing, which restores the reading frame, leading to the expression of a slightly truncated protein. Furthermore, the expression and correct deposition of C17 at the dermal-epidermal junction indicates its functionality. Thus, we assume AON-mediated exon skipping to be a promising tool for the treatment of junctional epidermolysis bullosa, particularly applicable in a personalized manner for rare genotypes.

Lipopolysaccharides as a communication signal for progression of legume endosymbiosis.

Establishment of a successful symbiosis between rhizobia and legumes results from an elaborate molecular dialogue between both partners. Bacterial nodulation (Nod) factors are indispensable for initiating plant responses, whereas bacterial surface polysaccharides are important for infection progression and nodule development. The mutant ORS571-oac2 of Azorhizobium caulinodans, affected in its surface polysaccharides, provokes a defective interaction with its host Sesbania rostrata. ORS571-oac2 induced structures with retarded development and continued generation of infection centers and organ primordia, leading to multilobed ineffective nodules. Bacterial development throughout the interaction occurred without major defects. A functional bidirectional complementation was obtained upon coinfection of ORS571-oac2 and a Nod factor-deficient mutant, indicating that the Fix- phenotype of ORS571-oac2-induced nodules resulted from the absence of a positive signal from ORS571-oac2. Indeed, the Fix- phenotype could be complemented by coinoculation of ORS571-oac2 with lipopolysaccharides (LPSs) purified from A. caulinodans. Our data show that Nod factors and LPSs are consecutive signals in symbiosis. Nod factors act first to trigger the onset of the nodulation and invasion program; LPSs inform the plant to proceed with the symbiotic interaction and to develop a functional fixation zone.