S100alpha and S100beta proteins in human cutaneous sensory corpuscles: effects of nerve and spinal cord injury.
S100 protein in the vertebrate peripheral nervous system consists of homo- or heterodimers of S100alpha and S100beta proteins, the first predominating in neurons and the second in glial cells. Recently, however, occurrence of S100beta protein in neurons has been reported. The expression of S100 protein by Schwann cells, as well as their derivatives in sensory corpuscles, depends on the sensory axon (i.e., the Schwann cell-axon contact). The present study analyzed the distribution of S100alpha and S100beta proteins in human cutaneous sensory corpuscles and the effects of peripheral or central sensory axon severance in the expression of these proteins. Simple or double immunohistochemistry was carried out using a panel of antibodies against S100alpha, S100beta or S100alpha+beta proteins, and the sections were examined by light or laser confocal scanning microscopy. Skin samples were obtained from normal subjects and patients with spinal cord injury, nerve entrapment, and nerve sections plus graft. The lamellar cells of Meissner corpuscles as well as the inner-core lamellae of the Pacinian corpuscles displayed strong immunoreactivity (IR) for all antigens examined, the most intense labeling being obtained for S100beta protein. The pattern of immunostaining was unchanged after spinal cord injury, whereas the number of stained corpuscles as well as the intensity of IR for each antigen decreased in cutaneous sensory corpuscles after nerve injury, both entrapment and section plus graft. No evidence was found of axonal labeling. The present results provide evidence that Schwann-related cells in human cutaneous sensory corpuscles contain both S100alpha and S100beta and that the expression of these proteins is dependent on the functional and structural integrity of sensory fibers.