RESUMO
Interleukin 13 (IL-13) has been shown to induce the death of activated microglia. We observed that IL-13, but not IL-4 or IL-10, significantly enhanced endoplasmic reticulum (ER) stress induction, apoptosis and death in microglia activated by lipopolysaccharide (LPS). IL-13 enhanced ER stress-regulated calpain activation and calpain-II expression in LPS-activated microglia. Calpain-II siRNA effectively reversed the IL-13 + LPS-activated caspase-12 activation. Expression of heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) was also increased in activated microglia, and this was effectively blocked by IL-13 and recombinant calpain. Both HO-1 inhibitor and PPAR-gamma antagonist augmented, but calpain inhibitor and PPAR-gamma agonists reversed, apoptosis induction in activated microglia. Transfection of PPAR-gamma siRNA effectively inhibited HO-1 protein expression in activated microglia. LPS stimulated transcriptional activation of HO-1 via an increase in PPAR-gamma DNA binding activity, which was reversed by IL-13. These results indicate that an ER stress-related calpain-down-regulated PPAR-gamma/HO-1 pathway is involved in the IL-13-enhanced activated death of microglia.
Assuntos
Calpaína/metabolismo , Retículo Endoplasmático/metabolismo , Heme Oxigenase-1/metabolismo , Interleucina-13/metabolismo , Isoenzimas/metabolismo , Microglia/fisiologia , PPAR gama/metabolismo , Estresse Fisiológico , Animais , Calpaína/antagonistas & inibidores , Calpaína/genética , Morte Celular/fisiologia , Células Cultivadas , Ativação Enzimática , Heme Oxigenase-1/genética , Interleucina-13/genética , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Lipopolissacarídeos/farmacologia , Camundongos , Microglia/citologia , Microglia/efeitos dos fármacos , Microglia/patologia , PPAR gama/genética , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
<p><b>OBJECTIVE</b>To perform molecular diagnosis for a Chinese pedigree with osteogenesis imperfecta type I.</p><p><b>METHODS</b>Thirty pairs of primers were designed to amplify all the 52 exons, exon boundaries and promoter region of the COL1A1 gene from genomic DNA of peripheral blood cells of the family members. The PCR products were purified and directly sequenced. To check the mutation in normal controls, the genomic DNA from peripheral blood cells of the index patient, his mother and 60 normal controls were analyzed by amplification refractory mutation system.</p><p><b>RESULTS</b>A missense mutation of GAT>CAT was identified at codon 1441 of the COL1A1 gene from the family, which resulted in the replacement of aspartic acid by histidine (D1441H). This mutation was not found in a group of 60 normal controls.</p><p><b>CONCLUSION</b>The method for molecular diagnosis of osteogenesis imperfecta was established and a novel COL1A1 gene mutation, D1441H, was identified in the Chinese pedigree with osteogenesis imperfecta type I.</p>
