Impact of different Ceramides to Structure of Stratum corneum lipid model membranes

• Applicant: Professor Dr. Reinhard Neubert
• Subject Area: Biological and Biomimetic Chemistry ; Pharmacy
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 111185811

• Final Report Year: 2012

Final Report Abstract

Within present project the importance of the investigation of Stratum corneum model membrane was demonstrated. The results of the artificial CER [EOS] specie showed that such a slight modification of the Iipid molecule does not affect the physico-chemical properties and that structural alignment of quaternary Iipid model membranes based on eit her CER[EOS] or CER[EOS]_branched was shown to be comparable. It was further shown that it does not induce a formation of the long-periodicity-phase as claimed typically in the presence of such long cha in ceramides. Furthermore, the molecules dynamic simulations underlined the neutron diffraction results. The MD Simulations opened up a new, additional possibility for arrangement of CER[EOS] within a model membrane containing also CER[AP], whereby the ω-acyl chain is inserted into the same membrane by folding back to the upper part of the chain above the carboxylic acid ester group. This new arrangement can only be proven experimentally by applying specifically deuterated CER[EOS]. This clearly necessitates the synthesis of this deuterated CER species for further evidence. However, the synthesis of the specifically deuterated CER species (either deuterated CER[EOS] or CER[AP] was much more complicated and time consuming than estimated. Consequently, this could not be realized up to now, but definitely it is necessary. Within the present project it could clearly be demonstrated that the mode of action of lipophilic penetration enhancers such as oleic acid or isopropyl myristate on a molecular level can be accomplished by using such simplified SC lipid model membranes. Furthermore, applying specifically deuterated penetration enhancers further proves the functioning of such molecules in SC lipid membranes. Consequently, for the final evidence of the conformation status of the ceramides, the mode of action of penetration enhancers and the functioning of other membrane components, the application of specifically deuterated lipids is indispensable. As this crucial step is very time-consuming and chemically intricate it is necessary to apply a PhD student rather than a diploma student with this work.

Publications

• Role of ceramide [AP] and ceramide [EOS] in the structural assembly of stratum corneum model membrane. BENSC Experimental Report, 2008. Helmholtz Zentrum Berlin für Materialien und Energie, Berlin
  A. Schroeter, T. Engelbrecht, R. Neubert, T. Hauß
  
• Basic nanostructure of stratum corneum lipid matrices based on ceramides [EOS] and [AP]: a neutron diffraction study, Biophysical Journal Vol. 97. 2009, Issue 4, pp.1104-1114.
  Schröter, A, Kessner, D, Kiselev, MA, Hauss, T, Dante, S, and Neubert, RHH.
  
• Neutron diffraction study of model membranes with complex Stratum corneum-like lipid composition. (2009) Helmholtz Zentrum Berlin für Materialien und Energie, Berlin.
  Engelbrecht, T, Schroeter, A, Hauß, T, and Neubert, RHH.
  
• Impact of the long chain [omega]-acylceramides on the stratum corneum lipid nanostructure. Part 1: Thermotropic phase behaviour of CER[EOS] and CER[EOP] studied using X-ray powder diffraction and FT-Raman spectroscopy. Chemistry and Physics of Lipids, Vol. 163. 2010, Issue 1, pp.42–50.
  Kessner, D, Brezesinski, G, Funari, SS, Dobner, B, and Neubert, RHH.
  
• Molecular Structure of the Stratum corneum Lipid Membrane: A New Theoretical Model for the Lipid matrix. Helmholtz Zentrum Berlin für Materialien und Energie, Berlin (2010)
  A. Schröter, T. Engelbrecht, T. Hauß, RHH Neubert
  
• Characterisation of a new ceramide EOS species: synthesis and investigation of the thermotropic phase behaviour and influence on the bilayer architecture of stratum corneum lipid model membranes. Soft Matter, Vol. 7.2011, pp. 8998-9011.
  Engelbrecht, TN, Hauss, T, Suss, K, Vogel, A, Roark, M, Feller, SE, Neubert, RHH, and Dobner, B.
  
• Lipophilic penetration enhancers and their impact to the bilayer structure of stratum corneum lipid model membranes: neutron diffraction studies based on the example oleic acid. Biochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 1808. 2011, Issue 12, pp 2798–2806.
  Engelbrecht, TN, Schroeter, A, Hauss, T, and Neubert, RHH.
  
• Characterization of lipid model membranes designed for studying impact of ceramide species on drug diffusion and penetration. European Journal of Pharmaceutics and Biopharmaceutics, Vol. 81. 2012, Issue 1, pp. 113–120.
  Ochalek, M, Heissler, S, Wohlrab, J, and Neubert, RH.
  
• Development and validation of LC/ESI-MS method for the detection and quantification of exogenous ceramide NP in stratum corneum and other layers of the skin. Journal of Pharmaceutical and Biomedical Analysis, Vol. 60. 2012, Pages 7–13.
  Sahle, FF, Lange, S, Dobner, B, Wohlrab, J., and Neubert, RH.
  
• Investigation of the nanostructure of stratum corneum lipid model systems, 9th International Conference and Workshop on Biological Barriers, Saarbrücken, Germany February 2012.
  A Schroeter, TN Engelbrecht, A Vogel, T Hauß, B Dobner, R.H.H Neubert
  
• Study of the Influence of the Penetration Enhancer Isopropyl Myristate on the Nanostructure of Stratum Corneum Lipid Model Membranes Using Neutron Diffraction and Deuterium-Labelling. Skin Pharmacology and Physiology, Vol. 25. 2012, pp. 200-207.
  Engelbrecht, TN, Demé, B, Dobner, B and Neubert, R. H.