M Y Ansari1, K Novak2, T M Haqqi3. 1. Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, 44272, OH, USA. Electronic address: mansari1@neomed.edu. 2. Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, 44272, OH, USA. Electronic address: knovak1@neomed.edu. 3. Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, 44272, OH, USA. Electronic address: thaqqi@neomed.edu.
Abstract
OBJECTIVE: To determine the Dynamin-related protein 1 (DRP1) regulation of mitochondrial fission in chondrocytes under pathological conditions, an area which is underexplored in osteoarthritis pathogenesis. DESIGN: DRP1 protein expression was determined by immunohistochemistry (IHC) or immunofluorescence (IF) staining of cartilage sections. IL-1β-induced DRP1 mRNA expression in chondrocytes was quantified by qPCR and protein expression by immunoblotting. Mitochondrial fragmentation in chondrocytes was visualized by MitoTracker staining or IF staining of mitochondrial marker proteins or by transient expression of mitoDsRed. Mitochondrial reactive oxygen species (ROS) levels were determined by MitoSOX staining. Apoptosis was determined by lactate dehydrogenase (LDH) release assay, Caspase 3/7 activity assay, propidium iodide (PI), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and IF staining of cleaved caspase 3. Cytochrome c release was determined by confocal microscopy. Surgical destabilization of the medial meniscus (DMM) was used to induce osteoarthritis (OA) in mice. RESULTS: Expression of DRP1 and mitochondrial damage was high in human OA cartilage and in the joints of mice subjected to DMM surgery which also showed increased chondrocytes apoptosis. IL-1β-induced mitochondrial network fragmentation and chondrocyte apoptosis via modulation of DRP1 expression and activity and induce apoptosis via Bax-mediated release of Cytochrome c. Pharmacological inhibition of DRP1 activity by Mdivi-1 blocked IL-1β-induced mitochondrial damage and apoptosis in chondrocytes. Additionally, IL-1β-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) is crucial for DRP1 activation and induction of mitochondrial network fragmentation in chondrocytes as these were blocked by inhibiting ERK1/2 activation. CONCLUSIONS: These findings demonstrate that ERK1/2 is a critical player in DRP1-mediated induction of mitochondrial fission and apoptosis in IL-1β-stimulated chondrocytes.
OBJECTIVE: To determine the Dynamin-related protein 1 (DRP1) regulation of mitochondrial fission in chondrocytes under pathological conditions, an area which is underexplored in osteoarthritis pathogenesis. DESIGN: DRP1 protein expression was determined by immunohistochemistry (IHC) or immunofluorescence (IF) staining of cartilage sections. IL-1β-induced DRP1 mRNA expression in chondrocytes was quantified by qPCR and protein expression by immunoblotting. Mitochondrial fragmentation in chondrocytes was visualized by MitoTracker staining or IF staining of mitochondrial marker proteins or by transient expression of mitoDsRed. Mitochondrial reactive oxygen species (ROS) levels were determined by MitoSOX staining. Apoptosis was determined by lactate dehydrogenase (LDH) release assay, Caspase 3/7 activity assay, propidium iodide (PI), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and IF staining of cleaved caspase 3. Cytochrome c release was determined by confocal microscopy. Surgical destabilization of the medial meniscus (DMM) was used to induce osteoarthritis (OA) in mice. RESULTS: Expression of DRP1 and mitochondrial damage was high in human OA cartilage and in the joints of mice subjected to DMM surgery which also showed increased chondrocytes apoptosis. IL-1β-induced mitochondrial network fragmentation and chondrocyte apoptosis via modulation of DRP1 expression and activity and induce apoptosis via Bax-mediated release of Cytochrome c. Pharmacological inhibition of DRP1 activity by Mdivi-1 blocked IL-1β-induced mitochondrial damage and apoptosis in chondrocytes. Additionally, IL-1β-induced activation of extracellular signal-regulated kinase 1/2 (ERK1/2) is crucial for DRP1 activation and induction of mitochondrial network fragmentation in chondrocytes as these were blocked by inhibiting ERK1/2 activation. CONCLUSIONS: These findings demonstrate that ERK1/2 is a critical player in DRP1-mediated induction of mitochondrial fission and apoptosis in IL-1β-stimulated chondrocytes.
Authors: Ann Cassidy-Stone; Jerry E Chipuk; Elena Ingerman; Cheng Song; Choong Yoo; Tomomi Kuwana; Mark J Kurth; Jared T Shaw; Jenny E Hinshaw; Douglas R Green; Jodi Nunnari Journal: Dev Cell Date: 2008-02 Impact factor: 12.270
Authors: Andrey S Marchev; Petya A Dimitrova; Andrew J Burns; Rumen V Kostov; Albena T Dinkova-Kostova; Milen I Georgiev Journal: Ann N Y Acad Sci Date: 2017-06-29 Impact factor: 5.691
Authors: Sang Woo Park; Keun-Young Kim; James D Lindsey; Yi Dai; Hwan Heo; Duy H Nguyen; Mark H Ellisman; Robert N Weinreb; Won-Kyu Ju Journal: Invest Ophthalmol Vis Sci Date: 2011-04-27 Impact factor: 4.799
Authors: Xueqi Gan; Shengbin Huang; Long Wu; Yongfu Wang; Gang Hu; Guangyue Li; Hongju Zhang; Haiyang Yu; Russell Howard Swerdlow; John Xi Chen; Shirley ShiDu Yan Journal: Biochim Biophys Acta Date: 2013-11-16