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1.
Bone Res ; 12(1): 41, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39019845

RESUMO

Mechanical overloading and aging are two essential factors for osteoarthritis (OA) development. Mitochondria have been identified as a mechano-transducer situated between extracellular mechanical signals and chondrocyte biology, but their roles and the associated mechanisms in mechanical stress-associated chondrocyte senescence and OA have not been elucidated. Herein, we found that PDZ domain containing 1 (PDZK1), one of the PDZ proteins, which belongs to the Na+/H+ Exchanger (NHE) regulatory factor family, is a key factor in biomechanically induced mitochondrial dysfunction and chondrocyte senescence during OA progression. PDZK1 is reduced by mechanical overload, and is diminished in the articular cartilage of OA patients, aged mice and OA mice. Pdzk1 knockout in chondrocytes exacerbates mechanical overload-induced cartilage degeneration, whereas intraarticular injection of adeno-associated virus-expressing PDZK1 had a therapeutic effect. Moreover, PDZK1 loss impaired chondrocyte mitochondrial function with accumulated damaged mitochondria, decreased mitochondrion DNA (mtDNA) content and increased reactive oxygen species (ROS) production. PDZK1 supplementation or mitoubiquinone (MitoQ) application alleviated chondrocyte senescence and cartilage degeneration and significantly protected chondrocyte mitochondrial functions. MRNA sequencing in articular cartilage from Pdzk1 knockout mice and controls showed that PDZK1 deficiency in chondrocytes interfered with mitochondrial function through inhibiting Hmgcs2 by increasing its ubiquitination. Our results suggested that PDZK1 deficiency plays a crucial role in mediating excessive mechanical load-induced chondrocyte senescence and is associated with mitochondrial dysfunction. PDZK1 overexpression or preservation of mitochondrial functions by MitoQ might present a new therapeutic approach for mechanical overload-induced OA.


Assuntos
Senescência Celular , Condrócitos , Camundongos Knockout , Mitocôndrias , Osteoartrite , Animais , Condrócitos/metabolismo , Condrócitos/patologia , Osteoartrite/patologia , Osteoartrite/metabolismo , Osteoartrite/genética , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Senescência Celular/efeitos dos fármacos , Humanos , Camundongos , Masculino , Camundongos Endogâmicos C57BL , Estresse Mecânico , Cartilagem Articular/patologia , Cartilagem Articular/metabolismo , Espécies Reativas de Oxigênio/metabolismo
2.
J Orthop Translat ; 45: 226-235, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38596341

RESUMO

Objectives: To investigate the potential role of Ribosomal protein L35 (RPL35) in regulating chondrocyte catabolic metabolism and to examine whether osteoarthritis (OA) progression can be delayed by overexpressing RPL35 in a mouse compression loading model. Methods: RNA sequencing analysis was performed on chondrocytes treated with or without 20 % elongation strain loading for 24 h. Experimental OA in mice was induced by destabilization of the medial meniscus and compression loading. Mice were randomly assigned to a sham group, an intra-articular adenovirus-mediated overexpression of the negative group, and an intra-articular adenovirus-mediated overexpression of the RPL35 operated group. The Osteoarthritis Research Society International score was used to evaluate cartilage degeneration. Immunostaining and western blot analyses were conducted to detect relative protein levels. Primary mouse chondrocytes were treated with 20 % elongation strain loading for 24 h to investigate the role of RPL35 in modulating chondrocyte catabolic metabolism and regulating cellular senescence in chondrocytes. Results: The protein expression of RPL35 in mouse chondrocytes was significantly reduced when excessive mechanical loading was applied, while elevated protein levels of RPL35 protected articular chondrocytes from degeneration. In addition, the RPL35 knockdown alone induced chondrocyte senescence, decreased the expression of anabolic markers, and increased the expression of catabolic markers in vitro in part through the hedgehog (Hh) pathway. Conclusions: These findings demonstrated a functional pathway important for OA development and identified intra-articular injection of RPL35 as a potential therapy for OA prevention and treatment. The translational potential of this article: It is necessary to develop new targeted drugs for OA due to the limitations of conventional pharmacotherapy. Our study explores and demonstrates the protective effect of RPL35 against excessive mechanical stress in OA models in vivo and in vitro in animals. These findings might provide novel insights into OA pathogenesis and show its translational potential for OA therapy.

3.
J Transl Med ; 21(1): 339, 2023 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-37217897

RESUMO

BACKGROUND: Disruption of N6 methyl adenosine (m6A) modulation hampers gene expression and cellular functions, leading to various illnesses. However, the role of m6A modification in osteoarthritis (OA) synovitis remains unclear. This study aimed to explore the expression patterns of m6A regulators in OA synovial cell clusters and identify key m6A regulators that mediate synovial macrophage phenotypes. METHODS: The expression patterns of m6A regulators in the OA synovium were illustrated by analyzing bulk RNA-seq data. Next, we built an OA LASSO-Cox regression prediction model to identify the core m6A regulators. Potential target genes of these m6A regulators were identified by analyzing data from the RM2target database. A molecular functional network based on core m6A regulators and their target genes was constructed using the STRING database. Single-cell RNA-seq data were collected to verify the effects of m6A regulators on synovial cell clusters. Conjoint analyses of bulk and single-cell RNA-seq data were performed to validate the correlation between m6A regulators, synovial clusters, and disease conditions. After IGF2BP3 was screened as a potential modulator in OA macrophages, the IGF2BP3 expression level was tested in OA synovium and macrophages, and its functions were further tested by overexpression and knockdown in vitro. RESULTS: OA synovium showed aberrant expression patterns of m6A regulators. Based on these regulators, we constructed a well-fitting OA prediction model comprising six factors (FTO, YTHDC1, METTL5, IGF2BP3, ZC3H13, and HNRNPC). The functional network indicated that these factors were closely associated with OA synovial phenotypic alterations. Among these regulators, the m6A reader IGF2BP3 was identified as a potential macrophage mediator. Finally, IGF2BP3 upregulation was verified in the OA synovium, which promoted macrophage M1 polarization and inflammation. CONCLUSIONS: Our findings revealed the functions of m6A regulators in OA synovium and highlighted the association between IGF2BP3 and enhanced M1 polarization and inflammation in OA macrophages, providing novel molecular targets for OA diagnosis and treatment.


Assuntos
Osteoartrite , Humanos , Dioxigenase FTO Dependente de alfa-Cetoglutarato , Inflamação/metabolismo , Macrófagos/metabolismo , Osteoartrite/genética , Fenótipo , Membrana Sinovial/metabolismo
4.
Cell Death Dis ; 13(10): 893, 2022 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-36273194

RESUMO

Noninflammatory clearance of dying cells by professional phagocytes, termed efferocytosis, is fundamental in both homeostasis and inflammatory fibrosis disease but has not been confirmed to occur in chronic pancreatitis (CP). Here, we investigated whether efferocytosis constitutes a novel regulatory target in CP and its mechanisms. PRSS1 transgenic (PRSS1Tg) mice were treated with caerulein to mimic CP development. Phospholipid metabolite profiling and epigenetic assays were performed with PRSS1Tg CP models. The potential functions of Atp8b1 in CP model were clarified using Atp8b1-overexpressing adeno-associated virus, immunofluorescence, enzyme-linked immunosorbent assay(ELISA), and lipid metabolomic approaches. ATAC-seq combined with RNA-seq was then used to identify transcription factors binding to the Atp8b1 promoter, and ChIP-qPCR and luciferase assays were used to confirm that the identified transcription factor bound to the Atp8b1 promoter, and to identify the specific binding site. Flow cytometry was performed to analyze the proportion of pancreatic macrophages. Decreased efferocytosis with aggravated inflammation was identified in CP. The lysophosphatidylcholine (LPC) pathway was the most obviously dysregulated phospholipid pathway, and LPC and Atp8b1 expression gradually decreased during CP development. H3K27me3 ChIP-seq showed that increased Atp8b1 promoter methylation led to transcriptional inhibition. Atp8b1 complementation substantially increased the LPC concentration and improved CP outcomes. Bhlha15 was identified as a transcription factor that binds to the Atp8b1 promoter and regulates phospholipid metabolism. Our study indicates that the acinar Atp8b1/LPC pathway acts as an important "find-me" signal for macrophages and plays a protective role in CP, with Atp8b1 transcription promoted by the acinar cell-specific transcription factor Bhlha15. Bhlha15, Atp8b1, and LPC could be clinically translated into valuable therapeutic targets to overcome the limitations of current CP therapies.


Assuntos
Adenosina Trifosfatases , Lisofosfatidilcolinas , Macrófagos , Pancreatite Crônica , Animais , Camundongos , Células Acinares/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Ceruletídeo/toxicidade , Histonas/metabolismo , Inflamação/metabolismo , Lisofosfatidilcolinas/genética , Lisofosfatidilcolinas/metabolismo , Macrófagos/metabolismo , Pancreatite Crônica/induzido quimicamente , Pancreatite Crônica/genética , Pancreatite Crônica/metabolismo , Proteínas de Transferência de Fosfolipídeos/genética , Proteínas de Transferência de Fosfolipídeos/metabolismo , Fatores de Transcrição/metabolismo
5.
Cell Death Dis ; 13(6): 567, 2022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35739102

RESUMO

Emerging evidence has shown an imbalance in M1/M2 macrophage polarization to play an essential role in osteoarthritis (OA) progression. However, the underlying mechanistic basis for this polarization is unknown. RNA sequencing of OA M1-polarized macrophages found highly expressed levels of pentraxin 3 (PTX3), suggesting a role for PTX3 in OA occurrence and development. Herein, PTX3 was found to be increased in the synovium and articular cartilage of OA patients and OA mice. Intra-articular injection of PTX3 aggravated, while PTX3 neutralization reversed synovitis and cartilage degeneration. No metabolic disorder or proteoglycan loss were observed in cartilage explants when treated with PTX3 alone. However, cartilage explants exhibited an OA phenotype when treated with culture supernatants of macrophages stimulated with PTX3, suggesting that PTX3 did not have a direct effect on chondrocytes. Therefore, the OA anti-chondrogenic effects of PTX3 are primarily mediated through macrophages. Mechanistically, PTX3 was upregulated by miR-224-5p deficiency, which activated the p65/NF-κB pathway to promote M1 macrophage polarization by targeting CD32. CD32 was expressed by macrophages, that when stimulated with PTX3, secreted abundant pro-inflammation cytokines that induced severe articular cartilage damage. The paracrine interaction between macrophages and chondrocytes produced a feedback loop that enhanced synovitis and cartilage damage. The findings of this study identified a functional pathway important to OA development. Blockade of this pathway and PTX3 may prevent and treat OA.


Assuntos
Proteína C-Reativa , MicroRNAs , Osteoartrite , Componente Amiloide P Sérico , Sinovite , Animais , Condrócitos/metabolismo , Humanos , Macrófagos , Camundongos , MicroRNAs/metabolismo , Osteoartrite/genética , Osteoartrite/metabolismo , Componente Amiloide P Sérico/genética , Componente Amiloide P Sérico/metabolismo , Sinovite/genética , Sinovite/metabolismo
6.
Nature ; 606(7916): 992-998, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35614223

RESUMO

Most cancer vaccines target peptide antigens, necessitating personalization owing to the vast inter-individual diversity in major histocompatibility complex (MHC) molecules that present peptides to T cells. Furthermore, tumours frequently escape T cell-mediated immunity through mechanisms that interfere with peptide presentation1. Here we report a cancer vaccine that induces a coordinated attack by diverse T cell and natural killer (NK) cell populations. The vaccine targets the MICA and MICB (MICA/B) stress proteins expressed by many human cancers as a result of DNA damage2. MICA/B serve as ligands for the activating NKG2D receptor on T cells and NK cells, but tumours evade immune recognition by proteolytic MICA/B cleavage3,4. Vaccine-induced antibodies increase the density of MICA/B proteins on the surface of tumour cells by inhibiting proteolytic shedding, enhance presentation of tumour antigens by dendritic cells to T cells and augment the cytotoxic function of NK cells. Notably, this vaccine maintains efficacy against MHC class I-deficient tumours resistant to cytotoxic T cells through the coordinated action of NK cells and CD4+ T cells. The vaccine is also efficacious in a clinically important setting: immunization following surgical removal of primary, highly metastatic tumours inhibits the later outgrowth of metastases. This vaccine design enables protective immunity even against tumours with common escape mutations.


Assuntos
Síndromes Mielodisplásicas , Neoplasias , Dermatopatias Genéticas , Vacinas , Antígenos de Histocompatibilidade Classe I , Humanos , Células Matadoras Naturais , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Neoplasias/prevenção & controle
7.
Adv Mater ; 34(15): e2108992, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34981867

RESUMO

Implantable meshes used in tension-free repair operations facilitate treatment of internal soft-tissue defects. However, clinical meshes fail to achieve anti-deformation, anti-adhesion, and pro-healing properties simultaneously, leading to undesirable surgery outcomes. Herein, inspired by the peritoneum, a novel biocompatible Janus porous poly(vinyl alcohol) hydrogel (JPVA hydrogel) is developed to achieve efficient repair of internal soft-tissue defects by a facile yet efficient strategy based on top-down solvent exchange. The densely porous and smooth bottom-surface of JPVA hydrogel minimizes adhesion of fibroblasts and does not trigger any visceral adhesion, and its loose extracellular-matrix-like porous and rough top-surface can significantly improve fibroblast adhesion and tissue growth, leading to superior abdominal wall defect treatment to commercially available PP and PCO meshes. With unique anti-swelling property (maximum swelling ratio: 6.4%), JPVA hydrogel has long-lasting anti-deformation performance and maintains high mechanical strength after immersion in phosphate-buffered saline (PBS) for 14 days, enabling tolerance to the maximum abdominal pressure in an internal wet environment. By integrating visceral anti-adhesion and defect pro-healing with anti-deformation, the JPVA hydrogel patch shows great prospects for efficient internal soft-tissue defect repair.


Assuntos
Parede Abdominal , Peritônio , Parede Abdominal/cirurgia , Materiais Biocompatíveis/farmacologia , Humanos , Hidrogéis , Porosidade , Aderências Teciduais
8.
Rheumatology (Oxford) ; 61(6): 2631-2643, 2022 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-34559207

RESUMO

OBJECTIVES: This study aimed to investigate the role and mechanism of asporin in modulating chondrocyte senescence in OA pathology. METHODS: Asporin and senescence-related hallmark expression were examined in human and experimental OA mouse cartilage samples. Twelve-week-old male C57 mice were administered with recombinant protein (rm-asporin)- or asporin-siRNA-expressing lentiviruses via intra-articular injection once a week after destabilization of the medial meniscus (DMM) surgery to induce OA. Cartilage damage was measured using the Osteoarthritis Research Society International score. Senescence-associated ß-galactosidase (SA-ß-Gal) staining, γH2AX, p21 and p16INK4a were analysed by immunofluorescence staining and western blot to assess the specific role of asporin in chondrocyte senescence. The TGF-ß1-Smad2 signalling pathway and miR-26b-5p were further evaluated to explore the mechanism of asporin in OA. RESULTS: Asporin was upregulated in articular chondrocytes of OA patients and DMM mice and accompanied by accumulation of senescent cells. Asporin overexpression exaggerated OA progression, whereas silencing asporin restored chondrocyte homeostasis and deferred chondrocyte senescence, leading to markedly attenuated DMM-induced OA. Cellular and molecular analyses showed that asporin can be inhibited by miR-26b-5p, which was significantly downregulated in OA cartilage, leading to exacerbation of experimental OA partially through inhibition of TGF-ß1-Smad2 signalling in chondrocytes. CONCLUSIONS: Our findings indicate that asporin plays an essential role in chondrocyte senescence and OA pathogenesis. Upregulated by miR-26b-5p, asporin inhibits the TGF-ß1-Smad2 pathway to accelerate chondrocyte senescence and exacerbate cartilage degeneration. Targeting the miR-26b-5p-asporin-Smad2 axis may serve as a practical therapeutic strategy to delay chondrocyte senescence and OA development.


Assuntos
Cartilagem Articular , MicroRNAs , Osteoartrite , Animais , Cartilagem Articular/metabolismo , Condrócitos/metabolismo , Humanos , Masculino , Meniscos Tibiais , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Osteoartrite/metabolismo , Proteína Smad2/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
9.
Cell Death Dis ; 12(6): 533, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34031369

RESUMO

Milk fat globule-epidermal growth factor (EGF) factor 8 (MFG-E8), as a necessary bridging molecule between apoptotic cells and phagocytic cells, has been widely studied in various organs and diseases, while the effect of MFG-E8 in osteoarthritis (OA) remains unclear. Here, we identified MFG-E8 as a key factor mediating chondrocyte senescence and macrophage polarization and revealed its role in the pathology of OA. We found that MFG-E8 expression was downregulated both locally and systemically as OA advanced in patients with OA and in mice after destabilization of the medial meniscus surgery (DMM) to induce OA. MFG-E8 loss caused striking progressive articular cartilage damage, synovial hyperplasia, and massive osteophyte formation in OA mice, which was relieved by intra-articular administration of recombinant mouse MFG-E8 (rmMFG-E8). Moreover, MFG-E8 restored chondrocyte homeostasis, deferred chondrocyte senescence and reprogrammed macrophages to the M2 subtype to alleviate OA. Further studies showed that MFG-E8 was inhibited by miR-99b-5p, expression of which was significantly upregulated in OA cartilage, leading to exacerbation of experimental OA partially through activation of NF-κB signaling in chondrocytes. Our findings established an essential role of MFG-E8 in chondrocyte senescence and macrophage reprogramming during OA, and identified intra-articular injection of MFG-E8 as a potential therapeutic target for OA prevention and treatment.


Assuntos
Antígenos de Superfície/fisiologia , Condrócitos/fisiologia , Macrófagos/fisiologia , Osteoartrite/genética , Animais , Antígenos de Superfície/genética , Células Cultivadas , Reprogramação Celular/genética , Senescência Celular/genética , Condrócitos/patologia , Feminino , Humanos , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/fisiologia , Proteínas do Leite/genética , NF-kappa B/metabolismo , Osteoartrite/patologia , Células RAW 264.7 , Transdução de Sinais/genética
10.
Mol Cell ; 79(1): 167-179.e11, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32497496

RESUMO

The identification of microRNA (miRNA) targets by Ago2 crosslinking-immunoprecipitation (CLIP) methods has provided major insights into the biology of this important class of non-coding RNAs. However, these methods are technically challenging and not easily applicable to an in vivo setting. To overcome these limitations and facilitate the investigation of miRNA functions in vivo, we have developed a method based on a genetically engineered mouse harboring a conditional Halo-Ago2 allele expressed from the endogenous Ago2 locus. By using a resin conjugated to the HaloTag ligand, Ago2-miRNA-mRNA complexes can be purified from cells and tissues expressing the endogenous Halo-Ago2 allele. We demonstrate the reproducibility and sensitivity of this method in mouse embryonic stem cells, developing embryos, adult tissues, and autochthonous mouse models of human brain and lung cancers. This method and the datasets we have generated will facilitate the characterization of miRNA-mRNA networks in vivo under physiological and pathological conditions.


Assuntos
Proteínas Argonautas/fisiologia , Células-Tronco Embrionárias/metabolismo , Glioma/metabolismo , MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Animais , Células-Tronco Embrionárias/citologia , Feminino , Regulação da Expressão Gênica , Glioma/genética , Glioma/patologia , Sequenciamento de Nucleotídeos em Larga Escala , Hidrolases/genética , Camundongos , Camundongos Knockout , MicroRNAs/genética , Ligação Proteica , RNA Mensageiro/genética , Proteínas Recombinantes de Fusão/genética
11.
Nat Commun ; 11(1): 2026, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-32332729

RESUMO

The cell-context dependency for RNA binding proteins (RBPs) mediated control of stem cell fate remains to be defined. Here we adapt the HyperTRIBE method using an RBP fused to a Drosophila RNA editing enzyme (ADAR) to globally map the mRNA targets of the RBP MSI2 in mammalian adult normal and malignant stem cells. We reveal a unique MUSASHI-2 (MSI2) mRNA binding network in hematopoietic stem cells that changes during transition to multipotent progenitors. Additionally, we discover a significant increase in RNA binding activity of MSI2 in leukemic stem cells compared with normal hematopoietic stem and progenitor cells, resulting in selective regulation of MSI2's oncogenic targets. This provides a basis for MSI2 increased dependency in leukemia cells compared to normal cells. Moreover, our study provides a way to measure RBP function in rare cells and suggests that RBPs can achieve differential binding activity during cell state transition independent of gene expression.


Assuntos
Diferenciação Celular/genética , Células-Tronco Hematopoéticas/patologia , Leucemia/genética , Células-Tronco Neoplásicas/patologia , Proteínas de Ligação a RNA/metabolismo , Adenosina Desaminase/genética , Animais , Sítios de Ligação/genética , Modelos Animais de Doenças , Proteínas de Drosophila/genética , Regulação Leucêmica da Expressão Gênica , Redes Reguladoras de Genes , Células HEK293 , Humanos , Leucemia/sangue , Leucemia/patologia , Camundongos , Camundongos Knockout , Cultura Primária de Células , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/genética , RNA-Seq , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo
12.
JCI Insight ; 4(23)2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31801909

RESUMO

NK cells contribute to protective antitumor immunity, but little is known about the functional states of NK cells in human solid tumors. To address this issue, we performed single-cell RNA-seq analysis of NK cells isolated from human melanoma metastases, including lesions from patients who had progressed following checkpoint blockade. This analysis identified major differences in the transcriptional programs of tumor-infiltrating compared with circulating NK cells. Tumor-infiltrating NK cells represented 7 clusters with distinct gene expression programs indicative of significant functional specialization, including cytotoxicity and chemokine synthesis programs. In particular, NK cells from 3 clusters expressed high levels of XCL1 and XCL2, which encode 2 chemokines known to recruit XCR1+ cross-presenting DCs into tumors. In contrast, NK cells from 2 other clusters showed a higher level of expression of cytotoxicity genes. These data reveal key features of NK cells in human tumors and identify NK cell populations with specialized gene expression programs.


Assuntos
Regulação Neoplásica da Expressão Gênica , Células Matadoras Naturais/imunologia , Linfócitos do Interstício Tumoral/imunologia , Melanoma/genética , Melanoma/imunologia , Metástase Neoplásica/imunologia , Linhagem Celular Tumoral , Quimiocinas/genética , Quimiocinas/metabolismo , Quimiocinas C , Apresentação Cruzada , Humanos , Imunidade Inata
13.
Nat Immunol ; 19(10): 1137-1145, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30224821

RESUMO

Numerous microRNAs and their target mRNAs are coexpressed across diverse cell types. However, it is unknown whether they are regulated in a manner independent of or dependent on cellular context. Here, we explored transcriptome-wide targeting and gene regulation by miR-155, whose activation-induced expression plays important roles in innate and adaptive immunity. Through mapping of miR-155 targets through differential iCLIP, mRNA quantification with RNA-seq, and 3' untranslated region (UTR)-usage analysis with poly(A)-seq in macrophages, dendritic cells, and T and B lymphocytes either sufficient or deficient in activated miR-155, we identified numerous targets differentially bound by miR-155. Whereas alternative cleavage and polyadenylation (ApA) contributed to differential miR-155 binding to some transcripts, in most cases, identical 3'-UTR isoforms were differentially regulated across cell types, thus suggesting ApA-independent and cellular-context-dependent miR-155-mediated gene regulation. Our study provides comprehensive maps of miR-155 regulatory networks and offers a valuable resource for dissecting context-dependent and context-independent miRNA-mediated gene regulation in key immune cell types.


Assuntos
Linfócitos B/imunologia , Células Dendríticas/imunologia , Regulação da Expressão Gênica/imunologia , Macrófagos/imunologia , MicroRNAs/imunologia , Linfócitos T/imunologia , Animais , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
14.
Nat Genet ; 49(6): 866-875, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28436985

RESUMO

The identity of the RNA-binding proteins (RBPs) that govern cancer stem cells remains poorly characterized. The MSI2 RBP is a central regulator of translation of cancer stem cell programs. Through proteomic analysis of the MSI2-interacting RBP network and functional shRNA screening, we identified 24 genes required for in vivo leukemia. Syncrip was the most differentially required gene between normal and myeloid leukemia cells. SYNCRIP depletion increased apoptosis and differentiation while delaying leukemogenesis. Gene expression profiling of SYNCRIP-depleted cells demonstrated a loss of the MLL and HOXA9 leukemia stem cell program. SYNCRIP and MSI2 interact indirectly though shared mRNA targets. SYNCRIP maintains HOXA9 translation, and MSI2 or HOXA9 overexpression rescued the effects of SYNCRIP depletion. Altogether, our data identify SYNCRIP as a new RBP that controls the myeloid leukemia stem cell program. We propose that targeting these RBP complexes might provide a novel therapeutic strategy in leukemia.


Assuntos
Regulação Leucêmica da Expressão Gênica , Ribonucleoproteínas Nucleares Heterogêneas/genética , Leucemia Mieloide/genética , Proteínas de Ligação a RNA/metabolismo , Animais , Sobrevivência Celular , Feminino , Hematopoese/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Leucemia Aguda Bifenotípica/genética , Leucemia Aguda Bifenotípica/patologia , Leucemia Mieloide/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Progenitoras Mieloides/metabolismo , Células Progenitoras Mieloides/patologia , RNA Interferente Pequeno , Proteínas de Ligação a RNA/genética , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Elife ; 42015 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-26575292

RESUMO

RBM15, an RNA binding protein, determines cell-fate specification of many tissues including blood. We demonstrate that RBM15 is methylated by protein arginine methyltransferase 1 (PRMT1) at residue R578, leading to its degradation via ubiquitylation by an E3 ligase (CNOT4). Overexpression of PRMT1 in acute megakaryocytic leukemia cell lines blocks megakaryocyte terminal differentiation by downregulation of RBM15 protein level. Restoring RBM15 protein level rescues megakaryocyte terminal differentiation blocked by PRMT1 overexpression. At the molecular level, RBM15 binds to pre-messenger RNA intronic regions of genes important for megakaryopoiesis such as GATA1, RUNX1, TAL1 and c-MPL. Furthermore, preferential binding of RBM15 to specific intronic regions recruits the splicing factor SF3B1 to the same sites for alternative splicing. Therefore, PRMT1 regulates alternative RNA splicing via reducing RBM15 protein concentration. Targeting PRMT1 may be a curative therapy to restore megakaryocyte differentiation for acute megakaryocytic leukemia.


Assuntos
Processamento de Proteína Pós-Traducional , Proteína-Arginina N-Metiltransferases/metabolismo , Splicing de RNA , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/metabolismo , Linhagem Celular , Humanos , Metilação , Proteólise , Ubiquitinação
16.
J Clin Invest ; 125(3): 1286-98, 2015 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-25664853

RESUMO

Leukemia stem cells (LSCs) are found in most aggressive myeloid diseases and contribute to therapeutic resistance. Leukemia cells exhibit a dysregulated developmental program as the result of genetic and epigenetic alterations. Overexpression of the RNA-binding protein Musashi2 (MSI2) has been previously shown to predict poor survival in leukemia. Here, we demonstrated that conditional deletion of Msi2 in the hematopoietic compartment results in delayed leukemogenesis, reduced disease burden, and a loss of LSC function in a murine leukemia model. Gene expression profiling of these Msi2-deficient animals revealed a loss of the hematopoietic/leukemic stem cell self-renewal program and an increase in the differentiation program. In acute myeloid leukemia patients, the presence of a gene signature that was similar to that observed in Msi2-deficent murine LSCs correlated with improved survival. We determined that MSI2 directly maintains the mixed-lineage leukemia (MLL) self-renewal program by interacting with and retaining efficient translation of Hoxa9, Myc, and Ikzf2 mRNAs. Moreover, depletion of MLL target Ikzf2 in LSCs reduced colony formation, decreased proliferation, and increased apoptosis. Our data provide evidence that MSI2 controls efficient translation of the oncogenic LSC self-renewal program and suggest MSI2 as a potential therapeutic target for myeloid leukemia.


Assuntos
Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide/metabolismo , Células-Tronco Neoplásicas/fisiologia , Proteínas de Ligação a RNA/fisiologia , Animais , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Humanos , Leucemia Mieloide/patologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ligação Proteica , Transcriptoma
17.
J Exp Med ; 211(1): 71-87, 2014 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-24395885

RESUMO

Hematopoietic stem cells (HSCs) are maintained through the regulation of symmetric and asymmetric cell division. We report that conditional ablation of the RNA-binding protein Msi2 results in a failure of HSC maintenance and engraftment caused by a loss of quiescence and increased commitment divisions. Contrary to previous studies, we found that these phenotypes were independent of Numb. Global transcriptome profiling and RNA target analysis uncovered Msi2 interactions at multiple nodes within pathways that govern RNA translation, stem cell function, and TGF-ß signaling. Msi2-null HSCs are insensitive to TGF-ß-mediated expansion and have decreased signaling output, resulting in a loss of myeloid-restricted HSCs and myeloid reconstitution. Thus, Msi2 is an important regulator of the HSC translatome and balances HSC homeostasis and lineage bias.


Assuntos
Divisão Celular/fisiologia , Hematopoese/fisiologia , Células-Tronco Hematopoéticas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais/fisiologia , Animais , Sequência de Bases , Linhagem da Célula/fisiologia , Ensaio de Unidades Formadoras de Colônias , Primers do DNA/genética , Citometria de Fluxo , Imunofluorescência , Imunoprecipitação , Camundongos , Camundongos Knockout , Análise em Microsséries , Dados de Sequência Molecular , Proteínas de Ligação a RNA/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA
18.
PLoS One ; 8(5): e63056, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23671654

RESUMO

Microsatellite instability (MSI) is characterized by the expansion or contraction of DNA repeat tracts as a consequence of DNA mismatch repair deficiency (MMRD). Accurate detection of MSI in cancer cells is important since MSI is associated with several cancer subtypes and can help inform therapeutic decisions. Although experimental assays have been developed to detect MSI, they typically depend on a small number of known microsatellite loci or mismatch repair genes and have limited reliability. Here, we report a novel genome-wide approach for MSI detection based on the global detection of insertions and deletions (indels) in microsatellites found in expressed genes. Our large-scale analyses of 20 cancer cell lines and 123 normal individuals revealed striking indel features associated with MSI: there is a significant increase of short microsatellite deletions in MSI samples compared to microsatellite stable (MSS) ones, suggesting a mechanistic bias of repair efficiency between insertions and deletions in normal human cells. By incorporating this observation into our MSI scoring metric, we show that our approach can correctly distinguish between MSI and MSS cancer cell lines. Moreover, when we applied this approach to primal tumor samples, our metric is also well consistent with diagnosed MSI status. Thus, our study offers new insight into DNA mismatch repair system, and also provides a novel MSI diagnosis method for clinical oncology with better reliability.


Assuntos
Neoplasias do Colo/genética , Instabilidade de Microssatélites , Neoplasias do Colo/diagnóstico , Neoplasias do Colo/metabolismo , Reparo de Erro de Pareamento de DNA , Marcadores Genéticos , Células HCT116 , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação INDEL , Técnicas de Diagnóstico Molecular , Análise de Sequência de DNA , Transcriptoma
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