Kosuke Saito

There is a strong association between Guillain-Barré syndrome (GBS) and Penner's serotype 19 (PEN 19) of Campylobacter jejuni. Sera from patients with GBS after C. jejuni infection have autoantibodies to GM1 ganglioside in the acute phase of the illness. Our previous work has suggested that GBS results from an immune response to cross-reactive antigen between lipopolysaccharide (LPS) of the Gram-negative bacterium and membrane components of peripheral nerves. To clarify the pathogenesis of GBS, we have investigated whether GM1-oligosaccharide structure is present in the LPS of C. jejuni (PEN 19) that was isolated from a GBS patient. After extraction of the LPS, the LPS showing the binding activity of cholera toxin, that specifically recognizes the GM1-oligosaccharide was purified by a silica bead column chromatography. Gas-liquid chromatography-mass spectrometric analysis has shown that the purified LPS contained Gal, GalNAc, and NeuAc, which are sugar components of GM1 ganglioside. 1H NMR methods [Carr-Purcell-Meiboom-Gill (CPMG), total correlation spectroscopy (TOCSY), and nuclear Overhauser effect spectroscopy (NOESY)] have revealed that the oligosaccharide structure [Gal beta 1-3 GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] protrude from the LPS core. This terminal structure [Gal beta 1-3GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta] is identical to the terminal tetrasaccharide of the GM1 ganglioside. This is the first study to demonstrate the existence of molecular mimicry between nerve tissue and the infectious agent that elicits GBS.

We isolated Campylobacter jejuni from 2 patients with Fisher's syndrome subsequent to enteritis. Crude lipopolysaccharide fractions were extracted from the bacteria and separated by thin-layer chromatography. Monoclonal antibodies to GQ1b ganglioside (GMR13 and 7F5) reacted with both lipopolysaccharide fractions, indicating that the lipopolysaccharides bear the GQ1b epitope. This is the first report of molecular mimicry between neural tissue components and the antecedent infectious agents of Fisher's syndrome.

The carbohydrate structures of lipopolysaccharides (LPSs) of Campylobacter jejuni strains belonging to Penner's serotypes (PEN) 1, 2, 4, 19, 23, and 36 were studied by thin-layer chromatography and immunostaining with several monoclonal antiganglioside antibodies. Anti-GM1 and anti-GD1a antibodies reacted with the LPSs of PEN 1, 4, and 19. Aspinall et al. (G. O. Aspinall, A. G. McDonald, T. S. Raju, H. Pang, A. P. Moran, and J. L. Penner. Eur. J. Biochem. 213:1017-1027, 1993) recently reported that the LPS of PEN 4 has a GD1a ganglioside-like structure rather than a GM1-like structure. We found that the LPS fraction of C. jejuni (PEN 4) has an LPS that bears a GM1 epitope as well as an LPS that bears a GD1a epitope.

Loss of vital functions in the somatic motor and sensory nervous systems can be induced by severe peripheral nerve transection with a long gap following trauma. In such cases, autologous nerve grafts have been used as the gold standard, with the expectation of activation and proliferation of graft-concomitant Schwann cells associated with their paracrine effects. However, there are a limited number of suitable sites available for harvesting of nerve autografts due to the unavoidable sacrifice of other healthy functions. To overcome this problem, the potential of skeletal muscle-derived multipotent stem cells (Sk-MSCs) was examined as a novel alternative cell source for peripheral nerve regeneration. Cultured/expanded Sk-MSCs were injected into severely crushed sciatic nerve corresponding to serious neurotmesis. After 4 weeks, engrafted Sk-MSCs preferentially differentiated into not only Schwann cells, but also perineurial/endoneurial cells, and formed myelin sheath and perineurium/endoneurium, encircling the regenerated axons. Increased vascular formation was also observed, leading to a favorable blood supply and waste product excretion. In addition, engrafted cells expressed key neurotrophic and nerve/vascular growth factor mRNAs; thus, endocrine/paracrine effects for the donor/recipient cells were also expected. Interestingly, skeletal myogenic capacity of expanded Sk-MSCs was clearly diminished in peripheral nerve niche. The same differentiation and tissue reconstitution capacity of Sk-MSCs was sufficiently exerted in the long nerve gap bridging the acellular conduit, which facilitated nerve regeneration/reconnection. These effects represent favorable functional recovery in Sk-MSC-treated mice, as demonstrated by good corduroy walking. We also demonstrated that these differentiation characteristics of the Sk-MSCs were comparable to native peripheral nerve-derived cells, whereas the therapeutic capacities were largely superior in Sk-MSCs. Therefore, Sk-MSCs can be a novel/suitable alternative cell source for healthy nerve autografts.