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
Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological fu...Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological function of OTUB2 in TNBC and uncover the underlying mechanisms.Methods:First,we found that the expression of OTUB2 was upregulated in TNBC by bioinformatics analysis,we then validated its expression in TNBC tissues and cells using immunohistochemistry(IHC)and qPCR and plotted the survival curves by Kaplan-Meier method.Gene set enrichment analysis(GSEA)suggested that OTUB2 may be involved in tumor proliferation and metastasis.Further functional assays,including Cell Counting Kit-8(CCK-8),colony formation,Transwell,and wound healing assays,were performed to assess the effects of OTUB2 overexpression and knockdown on TNBC cell proliferation and migration.Additionally,UbiBrowser 2.0 was used to identify OTUB2 substrate proteins and western blotting was conducted to clarify the molecular mechanisms involved.Results:Our results demonstrated that OTUB2 expression was elevated in TNBC and associated with poor prognosis.Overexpression of OTUB2 enhanced the proliferation and migration of TNBC cells,while its knockdown inhibited these processes.Moreover,OTUB2 stabilized tumor necrosis factor receptor-associated factor 6(TRAF6)by deubiquitinating it,leading to activation of the protein kinase B(AKT)pathway.Conclusions:OTUB2 exerts its promoting effects on the progression of TNBC by activating the TRAF6/AKT pathway.展开更多
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.
基金supported by the National Natural Science Foundation of China(No.82373380,Xinhua Xie).
文摘Objectives:Deubiquitinase OTUB2 plays a critical role in the progression of various tumors.However,its specific role in triple-negative breast cancer(TNBC)remains unclear.This study aims to elucidate the biological function of OTUB2 in TNBC and uncover the underlying mechanisms.Methods:First,we found that the expression of OTUB2 was upregulated in TNBC by bioinformatics analysis,we then validated its expression in TNBC tissues and cells using immunohistochemistry(IHC)and qPCR and plotted the survival curves by Kaplan-Meier method.Gene set enrichment analysis(GSEA)suggested that OTUB2 may be involved in tumor proliferation and metastasis.Further functional assays,including Cell Counting Kit-8(CCK-8),colony formation,Transwell,and wound healing assays,were performed to assess the effects of OTUB2 overexpression and knockdown on TNBC cell proliferation and migration.Additionally,UbiBrowser 2.0 was used to identify OTUB2 substrate proteins and western blotting was conducted to clarify the molecular mechanisms involved.Results:Our results demonstrated that OTUB2 expression was elevated in TNBC and associated with poor prognosis.Overexpression of OTUB2 enhanced the proliferation and migration of TNBC cells,while its knockdown inhibited these processes.Moreover,OTUB2 stabilized tumor necrosis factor receptor-associated factor 6(TRAF6)by deubiquitinating it,leading to activation of the protein kinase B(AKT)pathway.Conclusions:OTUB2 exerts its promoting effects on the progression of TNBC by activating the TRAF6/AKT pathway.
