Temporomandibular joint osteoarthritis(TMJ-OA) affects a significant proportion of the population worldwide.However,there has been no substantial progress in the development of FDA-approved drugs for treatment due to ...Temporomandibular joint osteoarthritis(TMJ-OA) affects a significant proportion of the population worldwide.However,there has been no substantial progress in the development of FDA-approved drugs for treatment due to a lack of understanding of the specific factors regulating key TMJ-OA molecular mechanisms.Lysyl Oxidase-Like-2(LOXL2) promotes knee joint cartilage protection and is down regulated in a TMJ-OA animal model.We evaluated the role of LOXL2 in TMJ cartilage,its molecular mechanism,and gene networks using in vivo Loxl2 knockout mice(Acan-Cre;Loxl2^(flox/flox)) and ex vivo goat TMJ cartilage.Our results show that Loxl2 knockout in mouse cartilage upregulates Il1b,Mmp9,Mmp13,Adamts4,and Adamts5,but reduces the levels of aggrecan and proteoglycan.Loxl2 deleted TMJ cartilage show a higher enrichment of inflammatory response,TNFA signaling via NF-κB,extracellular matrix(ECM),and collagen degradation pathway network.Conversely,LOXL2 treatment reduces interleukin-1beta(IL-1β)-induced expression of Mmp13,protects mitochondrial function,and ECM from degeneration.Importantly,LOXL2attenuates IL-1 β-induced chondrocyte apoptosis via the phosphorylation of NF-κB and expression of the pain-related gene PTGS2(encodes COX2).Taken together,Loxl2 knockout mice exacerbate TMJ-OA through cartilage/ECM degradation,mitochondrial dysfunction,chondrocyte apoptosis,and inflammatory gene expression,whereas LOXL2 treatment mitigate these effects.展开更多
基金supported by an NIH grant R01 DE031413 (M.V.B.)。
文摘Temporomandibular joint osteoarthritis(TMJ-OA) affects a significant proportion of the population worldwide.However,there has been no substantial progress in the development of FDA-approved drugs for treatment due to a lack of understanding of the specific factors regulating key TMJ-OA molecular mechanisms.Lysyl Oxidase-Like-2(LOXL2) promotes knee joint cartilage protection and is down regulated in a TMJ-OA animal model.We evaluated the role of LOXL2 in TMJ cartilage,its molecular mechanism,and gene networks using in vivo Loxl2 knockout mice(Acan-Cre;Loxl2^(flox/flox)) and ex vivo goat TMJ cartilage.Our results show that Loxl2 knockout in mouse cartilage upregulates Il1b,Mmp9,Mmp13,Adamts4,and Adamts5,but reduces the levels of aggrecan and proteoglycan.Loxl2 deleted TMJ cartilage show a higher enrichment of inflammatory response,TNFA signaling via NF-κB,extracellular matrix(ECM),and collagen degradation pathway network.Conversely,LOXL2 treatment reduces interleukin-1beta(IL-1β)-induced expression of Mmp13,protects mitochondrial function,and ECM from degeneration.Importantly,LOXL2attenuates IL-1 β-induced chondrocyte apoptosis via the phosphorylation of NF-κB and expression of the pain-related gene PTGS2(encodes COX2).Taken together,Loxl2 knockout mice exacerbate TMJ-OA through cartilage/ECM degradation,mitochondrial dysfunction,chondrocyte apoptosis,and inflammatory gene expression,whereas LOXL2 treatment mitigate these effects.
