Increased matrix stiffness of nucleus pulposus(NP)tissue is a main feature of intervertebral disc degeneration(IVDD)and affects various functions of nucleus pulposus cells(NPCs).Glycolysis is the main energy source fo...Increased matrix stiffness of nucleus pulposus(NP)tissue is a main feature of intervertebral disc degeneration(IVDD)and affects various functions of nucleus pulposus cells(NPCs).Glycolysis is the main energy source for NPC survival,but the effects and underlying mechanisms of increased extracellular matrix(ECM)stiffness on NPC glycolysis remain unknown.In this study,hydrogels with different stiffness were established to mimic the mechanical environment of NPCs.Notably,increased matrix stiffness in degenerated NP tissues from IVDD patients was accompanied with impaired glycolysis,and NPCs cultured on rigid substrates exhibited a reduction in glycolysis.展开更多
Survival of motor neuron(SMN)protein encoded by SMN1 gene,is the essential and ubiquitously expressed protein in all tissues.Prior studies demonstrated that SMN deficiency impaired bone development,but the underlying ...Survival of motor neuron(SMN)protein encoded by SMN1 gene,is the essential and ubiquitously expressed protein in all tissues.Prior studies demonstrated that SMN deficiency impaired bone development,but the underlying mechanism of abnormal endochondral ossification remains obscure.Here,we showed SMN is involved in hypertrophic chondrocytes differentiation through regulating RNA splicing and protein degradation via analyzing single cell RNA-sequencing data of hypertrophic chondrocytes.Of note,SMN loss induced dwarfism and delayed endochondral ossification in Smn1 depletion-severe spinal muscular atrophy(SMA)mouse model and Smn1 chondrocyte conditional knockdown mouse.Histological analysis revealed that SMN deficiency expanded the zone of hypertrophic chondrocytes in the growth plates,but delayed turnover from hypertrophic to ossification zone.Widespread changes in endochondral ossification related gene expression and alternative splicing profiles were identified via RNA sequencing of growth plate cartilages from SMA mice on postnatal day 4.Importantly,Mass spectrometry-based proteomics analysis elucidated Y-box-binding protein 1(YBX1)as a vital SMN-binding factor,was decreased in SMA mice.YBX1 knockdown reproduced the aberrant gene expression and splicing changes observed in SMA growth plate cartilages.Comparing the binding proteins of SMN and YBX1 revealed TNF receptor-associated factor 6(TRAF6),which promoted ubiquitination degradation of YBX1.By conditionally deleting Smn1 in chondrocytes of WT mice and overexpressing Smn1 in chondrocytes of SMA mice,we proved that SMN expression in chondrocytes is critical for hypertrophic chondrocyte-mediated endochondral ossification.Collectively,these results demonstrate that SMN deficiency contributes to rapid systemic bone dysplasia syndrome by promoting TRAF6-induced ubiquitination degradation of YBX1 in growth plate cartilages of SMA mice.展开更多
基金supported by the National Nature Science Foundation of China(No.82002345 to J.D and 81902179 to L.S)the Gusu Talent Program(No.Qngg2022008 and GSWS2021027 to J.D)the Preliminary Research Project of the Second Affiliated Hospital of Soochow University(No.SDFEYBS1905 to J.D).
文摘Increased matrix stiffness of nucleus pulposus(NP)tissue is a main feature of intervertebral disc degeneration(IVDD)and affects various functions of nucleus pulposus cells(NPCs).Glycolysis is the main energy source for NPC survival,but the effects and underlying mechanisms of increased extracellular matrix(ECM)stiffness on NPC glycolysis remain unknown.In this study,hydrogels with different stiffness were established to mimic the mechanical environment of NPCs.Notably,increased matrix stiffness in degenerated NP tissues from IVDD patients was accompanied with impaired glycolysis,and NPCs cultured on rigid substrates exhibited a reduction in glycolysis.
基金supported by the National Nature Science Foundation of China(81902179)the Postdoctoral Science Foundation of China(2020T130308)+3 种基金the Key Medical Discipline of Jiangsu Province(JSDW202223)the Natural Science Foundation of Jiangsu Province(BK20221241)the Science and Technology Project of Suzhou(SKJY2021094)the Gusu Talent Program(GSWS2022046)。
文摘Survival of motor neuron(SMN)protein encoded by SMN1 gene,is the essential and ubiquitously expressed protein in all tissues.Prior studies demonstrated that SMN deficiency impaired bone development,but the underlying mechanism of abnormal endochondral ossification remains obscure.Here,we showed SMN is involved in hypertrophic chondrocytes differentiation through regulating RNA splicing and protein degradation via analyzing single cell RNA-sequencing data of hypertrophic chondrocytes.Of note,SMN loss induced dwarfism and delayed endochondral ossification in Smn1 depletion-severe spinal muscular atrophy(SMA)mouse model and Smn1 chondrocyte conditional knockdown mouse.Histological analysis revealed that SMN deficiency expanded the zone of hypertrophic chondrocytes in the growth plates,but delayed turnover from hypertrophic to ossification zone.Widespread changes in endochondral ossification related gene expression and alternative splicing profiles were identified via RNA sequencing of growth plate cartilages from SMA mice on postnatal day 4.Importantly,Mass spectrometry-based proteomics analysis elucidated Y-box-binding protein 1(YBX1)as a vital SMN-binding factor,was decreased in SMA mice.YBX1 knockdown reproduced the aberrant gene expression and splicing changes observed in SMA growth plate cartilages.Comparing the binding proteins of SMN and YBX1 revealed TNF receptor-associated factor 6(TRAF6),which promoted ubiquitination degradation of YBX1.By conditionally deleting Smn1 in chondrocytes of WT mice and overexpressing Smn1 in chondrocytes of SMA mice,we proved that SMN expression in chondrocytes is critical for hypertrophic chondrocyte-mediated endochondral ossification.Collectively,these results demonstrate that SMN deficiency contributes to rapid systemic bone dysplasia syndrome by promoting TRAF6-induced ubiquitination degradation of YBX1 in growth plate cartilages of SMA mice.
