Search

Hyo Jung Shin,1,2 Hyewon Park,1,2 Nara Shin,1,2 Juhee Shin,1,2 Do Hyeong Gwon,1,2 Hyeok Hee Kwon,1,3 Yuhua Yin,1,2 Jeong-Ah Hwang,1,2 Jinpyo Hong,2 Jun Young Heo,1,4,5 Cuk-Seong Kim,1,6 Yongbum Joo,7 Youngmo Kim,7 Jinhyun Kim,8 Jaewon Beom,9 Dong Woon Kim1,2 1Department of Medical Science, Chungnam National University College of Medicine, Daejeon 35015, Republic of Korea; 2Department of Anatomy and Cell Biology, Brain Research Institute, Chungnam National University College of Medicine, Daejeon 35015, Republic of Korea; 3Department of Pediatrics; 4Biochemistry; 5Infection Control Convergence Research Center; 6Physiology Chungnam National University College of Medicine, Daejeon, Republic of Korea; 7Department of Orthopedics, Chungnam National University College of Medicine, Daejeon, Republic of Korea; 8Division of Rheumatology, Department of Internal Medicine, Chungnam National University College of Medicine, Daejeon, Republic of Korea; 9Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of KoreaCorrespondence: Dong Woon Kim DVM., PhD.Department of Anatomy and Cell Biology, Chungnam National University College of Medicine, 266 Munhwa-Ro, Chung-Gu, Daejeon 35015, Republic of KoreaTel +82-42-580-8201Fax +82-42-586-4800Email visnu528@cnu.ac.krJinhyun Kim, MD., PhD.Department of Internal Medicine, Chungnam National University College of Medicine, 266 Munhwa-Ro, Chung-Gu, Daejeon 35015, Republic of KoreaTel +82-42-338-2420Fax +82-42-586-4800Email jkim@cnuh.co.krBackground: Osteoarthritis (OA) is the most common type of joint disease associated with cartilage breakdown. However, the role played by mitochondrial dysfunction in OA remains inadequately understood. Therefore, we investigated the role played by p66shc during oxidative damage and mitochondrial dysfunction in OA and the effects of p66shc downregulation on OA progression.Methods: Monosodium iodoacetate (MIA), which is commonly used to generate OA animal models, inhibits glycolysis and biosynthetic processes in chondrocytes, eventually causing cell death. To observe the effects of MIA and poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles, histological analysis, immunohistochemistry, micro-CT, mechanical paw withdrawal thresholds, quantitative PCR, and measurement of oxygen consumption rate and extracellular acidification rate were conducted.Results: p-p66shc was highly expressed in cartilage from OA patients and rats with MIA-induced OA. MIA caused mitochondrial dysfunction and reactive oxygen species (ROS) production, and the inhibition of p66shc phosphorylation attenuated MIA-induced ROS production in human chondrocytes. Inhibition of p66shc by PLGA-based nanoparticles-delivered siRNA ameliorated pain behavior, cartilage damage, and inflammatory cytokine production in the knee joints of MIA-induced OA rats.Conclusion: p66shc is involved in cartilage degeneration in OA. By delivering p66shc-siRNA-loaded nanoparticles into the knee joints with OA, mitochondrial dysfunction-induced cartilage damage can be significantly decreased. Thus, p66shc siRNA PLGA nanoparticles may be a promising option for the treatment of OA.Keywords: osteoarthritis, monosodium iodoacetate, p66shc, ROS, mitochondrial dysfunction, PLGA-based nanoparticles

Min-Hee Yi,1 Juhee Shin,2,3 Nara Shin,2,3 Yuhua Yin,2,4 Sun Yeul Lee,4 Cuk-Seong Kim,3,5 Sang Ryong Kim,6 Enji Zhang,7 Dong Woon Kim2,31Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; 2Department of Anatomy, Brain Research Institute, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 3Department of Medical Science, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 4Department of Anesthesiology and Pain Medicine, Chungnam National University Hospital, Daejeon 301-747, South Korea; 5Department of Physiology, Chungnam National University School of Medicine, Daejeon 301-747, Republic of Korea; 6School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Institute of Life Science & Biotechnology, Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Republic of Korea; 7Department of Anesthesia Medicine, Yanbian University Hospital, Yanbian 133000, People’s Republic of ChinaBackground: Mitophagy is the selective engulfment of mitochondria by autophagosomes and the subsequent mitochondrial catabolism by lysosomes. Evidence has suggested an important role for mitochondrial dynamics and mitophagic flux in the development of many different neurodegenerative diseases.Objectives: The potential role of the mechanism underlying mitochondrial dynamics and mitophagic flux as it may relate to neuropathic pain is not well understood. This is a disease that largely remains an area of mechanistic uncertainty. PINK1 is a PTEN-induced mitochondrial kinase that can be selectively activated under mitochondrial stress conditions and lead to the induction of mitophagy.Materials and methods: A neuropathic pain rat model was established via spinal nerve ligation (SNL) and nociception was assayed via the von Frey filament method. Increased expression of PINK1 and the mechanism of mitophagy was detected in GABAergic interneurons of dorsal horn neurons of mice that underwent L5 SNL in comparison to control mice counterparts (n=8, P

Neuropathic pain (NP) is caused by lesions of the peripheral fibers and central neurons in the somatosensory nervous system and affects 7–10% of the general population. Although the distinct cause of neuropathic pain has been investigated in primary afferent neurons over the years, pain modulation by central sensitization remains controversial. NP is believed to be driven by cell type-specific spinal synaptic plasticity in the dorsal horn. Upon intense afferent stimulation, spinothalamic tract neurons are potentiated, whereas GABAergic interneurons are inhibited leading to long-term depression. Growing evidences suggest that the inhibition of GABAergic neurons plays pivotal roles in the manifestation of neuropathic and inflammatory pain states. Downregulation of GABA transmission and impairment of GABAergic interneurons in the dorsal horn are critical consequences after spinal cord and peripheral nerve injuries. These impairments in GABAergic interneurons may be associated with dysfunctional autophagy, resulting in neuropathic pain. Here, we review an emerging number of investigations that suggest a pivotal role of impaired autophagy of GABAergic interneurons in NP. We discuss relevant research spurring the development of new targets and therapeutic agents of NP and emphasize the need for a multidisciplinary approach to manage NP in the future.