It is well known from previous studies that polysulfated glycosaminoglycans (GAG) are able to stimulate wound healing processes by their selective binding to cytokines and growth factors. During the new funding period of the Transregio we will investigate structure activity relationships of sulfated oligohyaluronans (oligo-HA) as ligands for mediators and growth factors as well as building blocks of the aECM in detail.

The synthesis of sulfated oligo-HA was successfully established by using chemoenzymatic methods. Using this approach some hyaluronan tetra-, hexa-, and octasaccharides with defined sulfation patterns could be already synthesized. The selective protection and ligation of the reducing anomeric end led to different fluorescence- and spin-labeled HA conjugates which were used for binding assays, structural characterization, immobilization on surfaces, and for functional biological studies. The obtained activity profiles will now be used for the development of specific, custom-made protein ligands. Finally, these optimized protein ligands will be used to synthesize rationally designed biomaterials (particularly GAG with defined sulfation patterns). Artificial but comparably small proteoglycans and sulfated GAG-conjugated proteins will be developed as multivalent assemblies of GAG with defined sulfation patterns.

The successful multi-dimensional mass spectrometric (MS) characterization of polysulfated compounds is aggravated by the lability of the sulfate ester linkage (and to a minor extent also by the glycosidic linkages). We have already shown with weakly sulfated reference compounds that ion mobility MS is an excellent tool to characterized isomeric carbohydrate sulfates. Subsequent to careful tuning of the instrument parameters the detection of such compounds can be achieved without major fragmentation. This work will be now extended for polysulfated compounds. Finally, we will compare these data with PFG-(pulsed field gradient)-NMR measurements. This is important because no fragmentation will be induced under conditions of NMR and the investigations can be performed in aqueous solution not in the gas phase.