Mechanical deformation inhibits IL-10 and stimulates IL-12 production by mouse calvarial osteoblasts in vitro

The skeleton is continuously remodelled throughout life, a process that is orchestrated by cells of the osteoblast lineage. Remodelling involves a complex network of cell-cell signalling involving systemic hormones, locally produced cytokines, growth factors and the mechanical environment of the cells. Here, we report on the effect of mechanically-induced strain on the synthesis by mouse calvarial osteoblasts in monolayer culture of IL-10 and IL-12, two cytokines that inhibit osteoclast formation in bone marrow cultures; IL-10 also suppresses osteoblast differentiation suggesting a role for both cytokines in bone physiology. A tensile strain was applied to the cells intermittently for 6s, every 90s, for 2-96h. After 2-h culture, supernatants from deformed cells contained significantly less IL-10 than control cultures. In contrast, mechanical deformation had a stimulatory effect on IL-12 synthesis; however, by 48h both had returned to control levels. These data suggest that IL-10 and IL-12 can be added to the growing list of mechanical stress-responsive genes. The down-regulation of IL-10 and stimulation of IL-12 further suggests that the initial response of the cells to mechanical deformation was an osteogenic one.

Identification of a 20-kDa protein with calcium uptake transport activity. Reconstitution in a membrane model

This paper presents results of experiments designed to further purify the membrane system involved in mitochondrial calcium transport. A partially purified extract, which transported calcium with a specific activity of 1194 nmol 45Ca2+/mg protein/5 min, was used to obtain mouse hyperimmune serum. This serum inhibited calcium uptake both in mitoplasts and in vesicles reconstituted with mitochondrial proteins containing cytochrome oxidase. Western blot analysis of the semipurified fraction showed that the serum recognized specifically two antigens of 75 and 20 kDa. Both antibodies were purified by elution from the nitrocellulose sheets and their inhibition capacity was analyzed. The antibody that recognized the 20-kDa protein produced a higher degree of inhibition than the other one.

An analysis of the composition of the inflammatory infiltrate in autoimmune and hepatitis B virus-induced chronic liver disease

The composition of the mononuclear cell infiltrate in the liver was studied in patients with autoimmune and hepatitis B virus (HBV)-induced liver disease. The ratio of inducer to cytotoxic/suppressor cells was greater in patients with lupoid chronic active liver disease, primary biliary cirrhosis, and HBeAb positive HBV-induced chronic active liver disease than in patients with HBeAg positive HBV-induced chronic hepatitis. In patients with chronic HBV-induced (HBeAb positive) liver disease, this ratio was greater in the periportal/portal area than in the lobule. These data are consistent with a relative deficiency of the cytotoxic/suppressor population of T cells in autoimmune liver diseases and possibly in HBeAb positive HBV-induced chronic active liver disease. In the latter patients, different ratios in the periportal and centrilobular zones suggest different mechanisms for periportal and lobular hepatitis.