OBJECTIVE: Nuclear protein 1 (Nupr1) is a stress-inducible protein that is involved in gene transcription. The present study was undertaken to determine whether chondrocytes express Nupr1 and whether Nupr1 regulates matrix metalloproteinase 13 (MMP-13) expression. METHODS: Paraffin-embedded cartilage sections from normal human and osteoarthritic (OA) cartilage were immunostained using anti-Nupr1 antibody. To measure Nupr1 expression, total RNA was isolated from joint tissue obtained 8 weeks after surgery from young (12-week-old) and older (12-month-old) mice that underwent destabilization of the medial meniscus (DMM) to induce OA. Human chondrocytes were stimulated with 1-10 ng/ml interleukin-1β (IL-1β), 25 μM tert-butyl-hydroperoxide (tBHP), or 2 μM thapsigargin, and Nupr1 expression was analyzed by quantitative polymerase chain reaction. In addition, chondrocytes were transfected with small interfering RNA to knock down Nupr1 expression and then stimulated overnight with IL-1β. After incubation, the conditioned medium was collected and MMP levels measured. RESULTS: Increased Nupr1 immunostaining was noted in human OA cartilage compared to normal cartilage. Expression was also increased in joint tissue from 12-month-old mice that underwent DMM surgery compared to sham-operated controls. Stimulation of chondrocytes with IL-1β induced a 2-fold increase in Nupr1 messenger RNA (mRNA) within 1 hour, with the increase peaking to 4-fold at 6 hours. Treatment of chondrocytes with tBHP to induce oxidative stress increased Nupr1 mRNA expression by >2-fold; treatment with thapsigargin to induce endoplasmic reticulum stress did not produce a similar effect. Knockdown of Nupr1 inhibited IL-1β-mediated induction of MMP-13. CONCLUSION: Nupr1 is expressed in cartilage, and its levels are increased in OA. Nupr1 expression is required for IL-1β-mediated expression of MMP-13. These findings provide evidence of a novel pathway for regulation of IL-1β-mediated production of MMPs in chondrocytes.
OBJECTIVE:Nuclear protein 1 (Nupr1) is a stress-inducible protein that is involved in gene transcription. The present study was undertaken to determine whether chondrocytes express Nupr1 and whether Nupr1 regulates matrix metalloproteinase 13 (MMP-13) expression. METHODS:Paraffin-embedded cartilage sections from normal human and osteoarthritic (OA) cartilage were immunostained using anti-Nupr1 antibody. To measure Nupr1 expression, total RNA was isolated from joint tissue obtained 8 weeks after surgery from young (12-week-old) and older (12-month-old) mice that underwent destabilization of the medial meniscus (DMM) to induce OA. Human chondrocytes were stimulated with 1-10 ng/ml interleukin-1β (IL-1β), 25 μM tert-butyl-hydroperoxide (tBHP), or 2 μM thapsigargin, and Nupr1 expression was analyzed by quantitative polymerase chain reaction. In addition, chondrocytes were transfected with small interfering RNA to knock down Nupr1 expression and then stimulated overnight with IL-1β. After incubation, the conditioned medium was collected and MMP levels measured. RESULTS: Increased Nupr1 immunostaining was noted in humanOA cartilage compared to normal cartilage. Expression was also increased in joint tissue from 12-month-old mice that underwent DMM surgery compared to sham-operated controls. Stimulation of chondrocytes with IL-1β induced a 2-fold increase in Nupr1 messenger RNA (mRNA) within 1 hour, with the increase peaking to 4-fold at 6 hours. Treatment of chondrocytes with tBHP to induce oxidative stress increased Nupr1 mRNA expression by >2-fold; treatment with thapsigargin to induce endoplasmic reticulum stress did not produce a similar effect. Knockdown of Nupr1 inhibited IL-1β-mediated induction of MMP-13. CONCLUSION:Nupr1 is expressed in cartilage, and its levels are increased in OA. Nupr1 expression is required for IL-1β-mediated expression of MMP-13. These findings provide evidence of a novel pathway for regulation of IL-1β-mediated production of MMPs in chondrocytes.
Authors: M Mathy-Hartert; L Hogge; C Sanchez; G Deby-Dupont; J M Crielaard; Y Henrotin Journal: Osteoarthritis Cartilage Date: 2008-03-04 Impact factor: 6.576
Authors: Philipp S Lange; Juan C Chavez; John T Pinto; Giovanni Coppola; Chiao-Wang Sun; Tim M Townes; Daniel H Geschwind; Rajiv R Ratan Journal: J Exp Med Date: 2008-05-05 Impact factor: 14.307
Authors: Isaac D Sheffield; Mercedes A McGee; Steven J Glenn; Da Young Baek; Joshua M Coleman; Bradley K Dorius; Channing Williams; Brandon J Rose; Anthony E Sanchez; Michael A Goodman; John M Daines; Dennis L Eggett; Val C Sheffield; Arminda Suli; David L Kooyman Journal: Front Physiol Date: 2018-06-19 Impact factor: 4.566