SUMMARYThe structure and motility of isolated rat primary (I) Schwann cells (SC) have been compared to that of subcultured (II) SC during and after mitotic stimulation. I SC contain myelin components which persist for 2 weeks in serum-free medium while they rapidly disappear in medium containing serum and high glucose concentration. These components were never detected in II SC. Both I SC and II SC after their mitotic phase are spindle-shaped, contain many intermediate and actin filaments, have no basement membrane but show intense migratory and undulatory activities. Rare fibroblasts in I cultures are recognized by their extremely variable shape, the presence of Thy 1.1 antigen in their membrane and their intense edge ruffling alternating with abrupt translocation. In contrast, I SC movements consist of intracellular translocation of nuclei along SC processes, which retract and extend constantly, and in slow rhythmic undulation episodes (2.3±0.2/min) alternating with migration at 135±50 µ/h. The total number of these episodes per day in serum-free medium is rigorously identical for different cells (166.3±0.2) and this uniformity of frequency suggests a genotypic basis. Cycles, consisting of an undulation episode followed by a resting interval, have mean durations of 8.6±4.1 min and a sharp peak of occurrence at 6 min, with exponential distribution of the longer periods. Motility of II SC is considerably inhibited during mitotic stimulation by cholera toxin and a pituitary extract while SC phenotype has changed to a flat multipolar cell with prominent Golgi and ribosomes. Migration is reduced to 24±2 µ/h and only 2 % of the SC show pulsations of the same periodicity as the I SC undulations. A dramatic increase in pulsation frequency occurs 6-12 h after removal of mitogenic factors when 80% of II SC start pulsating twice as fast for 2-3 days. When mitoses cease, SC quickly recover their SC phenotype with rhythmic undulations while migration speed increased to 92±20 µ/h. Thus, in spite of dramatic modification of shape, structure and behavior during mitotic stimulation, SC subsequently recover their unique motility pattern which might be essential for their myelinating function.Rat Schwann cells (SC), the myelin-form-ing cells of the peripheral nervous system, can now be cultured in isolation by using two different techniques [1][2][3]. In the first, rat dorsal root ganglia obtained just before birth are explanted and treated with antimitotic agents for a few days. After 10 days, the ganglia are excised and a "Schwann cell bed" is developed after the neurites are eliminated [1,2]. In the second technique, dissociation of newborn rat sciatic nerve results in a mixed population of SC and fibroblasts, which after 2 days of culturing are identified by their respective surface antigenic markers Ran 1 and Thy 1.1 [3,4]. In these cultures, fibroblast growth is first inhibited by AraC treatment and subsequently, by complement-mediated killing of Thy 1.1 positive cells [3]. SC growth can then be intensely stimulated by pi...

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Decline in immune function during aging increases susceptibility to different aging related diseases. However, the underlying molecular mechanisms, especially the genetic factors contributing to imbalance of naïve/memory T-cell subpopulations, still remain largely elusive. Here we show that loss of DJ-1 encoded by PARK7/DJ-1, causing early-onset familial Parkinson's disease (PD), unexpectedly delayed immunoaging in both human and mice. Compared with two gender-matched unaffected sibling carriers of similar ages, the index PD patient with DJ-1 deficiency showed a decline in many critical immunoaging features, including almost doubled frequencies of non-senescent T cells. The observation of a 'younger' immune system in the index patient was further consolidated by the results in aged DJ-1 knockout mice. Our data from bone marrow chimera models and adoptive transfer experiments demonstrated that DJ-1 regulates several immunoaging features via hematopoietic-intrinsic and naïve-CD8-intrinsic mechanisms. Our finding suggests an unrecognized critical role of DJ-1 in regulating immunoaging, discovering a potent target to interfere with immunoaging- and aging-associated diseases.

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