Dataset Information

Induction and degradation of the uncoupling protein thermogenin in brown adipocytes in vitro and in vivo. Evidence for a rapidly degradable pool.

ABSTRACT: The induction and degradation of the brown-fat-specific uncoupling protein thermogenin in brown fat cell cultures was investigated. Cultures were initiated with undifferentiated precursor cells from young mice and the amount of thermogenin was determined by immunoblotting. High levels of thermogenin could be induced by noradrenaline treatment in cells grown for more than 5 days in culture, and in such cell cultures continuously stimulated with noradrenaline, the thermogenin level continued to increase for at least a further 5 days. In cell cultures stimulated for only 24 h, the induced thermogenin was subsequently specifically and rapidly degraded, with a half-life of 20 h. As the half-life was prolonged by cycloheximide treatment, the degradation was apparently due to the induction of specific proteins after cessation of adrenergic stimulation. In cell cultures continuously stimulated with noradrenaline for 5 days, the induced thermogenin was degraded much more slowly after noradrenaline removal, with a half-life of 70 h. This half-life was unchanged by cycloheximide treatment, and the degradation after cycloheximide was in parallel with the degradation of protein in general, and was therefore non-specific. The prolongation of the half-life of thermogenin after the chronic treatment may be related to mitochondrial incorporation of thermogenin and consequent stabilization of the protein. The half-life of thermogenin in an in vivo situation of similar experimental design (the reacclimation of mice to warm after 5 days in the cold), was also long (about 7 days), and the loss was also non-specific, as it paralleled the loss of protein. Thus different molecular events are involved in thermogenin degradation when the protein is found in different functional pools.

SUBMITTER: Puigserver P

PROVIDER: S-EPMC1132651 | biostudies-other | 1992 Jun

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:UNLABELLED:Recent studies reveal many biomaterial vaccine carriers are able to activate immunostimulatory pathways, even in the absence of other immune signals. How the changing properties of polymers during biodegradation impact this intrinsic immunogenicity is not well studied, yet this information could contribute to rational design of degradable vaccine carriers that help direct immune response. We use degradable poly(beta-amino esters) (PBAEs) to explore intrinsic immunogenicity as a function of the degree of polymer degradation and polymer form (e.g., soluble, particles). PBAE particles condensed by electrostatic interaction to mimic a common vaccine approach strongly activate dendritic cells, drive antigen presentation, and enhance T cell proliferation in the presence of antigen. Polymer molecular weight strongly influences these effects, with maximum stimulation at short degradation times--corresponding to high molecular weight--and waning levels as degradation continues. In contrast, free polymer is immunologically inert. In mice, PBAE particles increase the numbers and activation state of cells in lymph nodes. Mechanistic studies reveal that this evolving immunogenicity occurs as the physicochemical properties and concentration of particles change during polymer degradation. This work confirms the immunological profile of degradable, synthetic polymers can evolve over time and creates an opportunity to leverage this feature in new vaccines. STATEMENT OF SIGNIFICANCE:Degradable polymers are increasingly important in vaccination, but how the inherent immunogenicity of polymers changes during degradation is poorly understood. Using common rapidly-degradable vaccine carriers, we show that the activation of immune cells--even in the absence of other adjuvants--depends on polymer form (e.g., free, particulate) and the extent of degradation. These changing characteristics alter the physicochemical properties (e.g., charge, size, molecular weight) of polymer particles, driving changes in immunogenicity. Our results are important as many common biomaterials (e.g., PLGA) are now known to exhibit immune activity that alters how vaccines are processed. Thus, the results of this study could contribute to more rational design of biomaterial carriers that also actively direct the properties of responses generated by vaccines.

Dataset Information

Induction and degradation of the uncoupling protein thermogenin in brown adipocytes in vitro and in vivo. Evidence for a rapidly degradable pool.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets