Neurodegenerative diseases, infectious pathologies and liquid crystals: Hypothesis of a common information vector...

The existence of an information vector common to very different pathologies is the hypothesis of one of us, the argumentation and discussion of which we present here. It is a mesomorphic state of material called liquid crystal. The liquid-ordered (Lo) phase, made up of membrane rafts mediated by cholesterol, lies at the center of our concept. This mesophase is either preexistent and then modified by the pathogenic process, or initiated by the latter. The most notable disorders involved are Alzheimer's, Parkinson's, Charcot and Creutzfeldt-Jakob diseases, flu-like illnesses and acquired immunodeficiency syndrome (AIDS), although this list may well be extended to include other anisotropic, birefringent amyloid proteinopathies, which have properties compatible with those of liquid crystals. Incidentally, numerous conventional infectious pathologies can also induce a mesomorphic state in cell membranes. It has already been established that mesophases contain the chemical information transmitted from the intramolecular microscopic level, where covalent bonds are applied. Information is then transmitted at the intermolecular macroscopic level, where it is made up of informed, self-organized collections. Electrostatic interactions, coordination of metallic ions, van der Waals forces and donor-acceptor interactions of hydrogen bonding all come into play. These reactions are produced notably in the nanodomains enriched by cholesterol and sphingolipids. Lipids in the cell membrane are where the phase separations favoring elastic hydrodynamic instabilities conducive to the Lo phase take place. In addition, perturbations of the mesomorphic states of membrane rafts due, for example, to lipid dysfunction-even mild ones-with an intracerebral or generalized location could bring about a displacement of thermodynamic equilibrium favoring the initiation and progression of the pathologies under consideration here. Indeed, the most recent work has rendered our hypothesis highly probable. Moreover, our hypothesis is supported by medical and biological observations arising essentially from biophysics and widely documented in the literature. Thus, these facts expand the number of diagnostic and therapeutic perspectives that could be evoked and perhaps even demand exploration.