RESUMO
During differentiation, human embryonic stem cells (hESCs) shut down the regulatory network conferring pluripotency in a process we designated pluripotent state dissolution (PSD). In a high-throughput RNAi screen using an inclusive set of differentiation conditions, we identify centrally important and context-dependent processes regulating PSD in hESCs, including histone acetylation, chromatin remodeling, RNA splicing, and signaling pathways. Strikingly, we detected a strong and specific enrichment of cell-cycle genes involved in DNA replication and G2 phase progression. Genetic and chemical perturbation studies demonstrate that the S and G2 phases attenuate PSD because they possess an intrinsic propensity toward the pluripotent state that is independent of G1 phase. Our data therefore functionally establish that pluripotency control is hardwired to the cell-cycle machinery, where S and G2 phase-specific pathways deterministically restrict PSD, whereas the absence of such pathways in G1 phase potentially permits the initiation of differentiation.
Assuntos
Ciclo Celular , Células-Tronco Embrionárias/citologia , Redes Reguladoras de Genes , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Diferenciação Celular , Ciclina B2/metabolismo , Células-Tronco Embrionárias/metabolismo , Epigênese Genética , Humanos , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Proteína Supressora de Tumor p53/metabolismoRESUMO
Purinergic signalling, consisting of extracellular purines and purinergic receptors, modulates cell proliferation, invasion and immunological reaction during cancer progression. Here, we focus on current evidence that suggests the crucial role of purinergic signalling in mediating cancer therapeutic resistance, the major obstacle in cancer treatment. Mechanistically, purinergic signalling can modulate the tumor microenvironment (TME), epithelial-mesenchymal transition (EMT) and anti-tumor immunity, thus affecting drug sensitivity of tumor cells. Currently, some agents attempting to target purinergic signalling either in tumor cells or in tumor-associated immune cells are under preclinical or clinical investigation. Moreover, nano-based delivery technologies significantly improve the efficacy of agents targeting purinergic signalling. In this review article, we summarize the mechanisms of purinergic signalling in promoting cancer therapeutic resistance and discuss the potentials and challenges of targeting purinergic signalling in future cancer treatment.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Neoplasias , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Transdução de Sinais , Proliferação de Células , Transição Epitelial-Mesenquimal , Microambiente TumoralRESUMO
Pruning, whereby neurons eliminate their excess neurites, is central for the maturation of the nervous system. In Drosophila, sensory neurons, ddaCs, selectively prune their larval dendrites without affecting their axons during metamorphosis. However, it is unknown whether the secretory pathway plays a role in dendrite pruning. Here, we show that the small GTPase Arf1, an important regulator of the secretory pathway, is specifically required for dendrite pruning of ddaC/D/E sensory neurons but dispensable for apoptosis of ddaF neurons. Analyses of the GTP- and GDP-locked forms of Arf1 indicate that the cycling of Arf1 between GDP-bound and GTP-bound forms is essential for dendrite pruning. We further identified Sec71 as a guanine nucleotide exchange factor for Arf1 that preferentially interacts with its GDP-bound form. Like Arf1, Sec71 is also important for dendrite pruning, but not for apoptosis, of sensory neurons. Arf1 and Sec71 are interdependent for their localizations on Golgi. Finally, we show that the Sec71/Arf1-mediated trafficking process is a prerequisite for Rab5-dependent endocytosis to facilitate endocytosis and degradation of the cell-adhesion molecule Neuroglian (Nrg).
Assuntos
Fator 1 de Ribosilação do ADP/fisiologia , Drosophila , Fatores de Troca do Nucleotídeo Guanina/fisiologia , Plasticidade Neuronal/genética , Células Receptoras Sensoriais/fisiologia , Fator 1 de Ribosilação do ADP/metabolismo , Animais , Animais Geneticamente Modificados , Apoptose/genética , Drosophila/genética , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Fatores de Troca do Nucleotídeo Guanina/genética , Metamorfose Biológica/fisiologia , Via Secretória/genéticaRESUMO
Centromeric identity and chromosome segregation are determined by the precise centromeric targeting of CENP-A, the centromere-specific histone H3 variant. The significance of the amino-terminal domain (NTD) of CENP-A in this process remains unclear. Here, we assessed the functional significance of each residue within the NTD of CENP-A from Schizosaccharomyces pombe (SpCENP-A) and identified a proline-rich 'GRANT' (Genomic stability-Regulating site within CENP-A N-Terminus) motif that is important for CENP-A function. Through sequential mutagenesis, we show that GRANT proline residues are essential for coordinating SpCENP-A centromeric targeting. GRANT proline-15 (P15), in particular, undergoes cis-trans isomerization to regulate chromosome segregation fidelity, which appears to be carried out by two FK506-binding protein (FKBP) family prolyl cis-trans isomerases. Using proteomics analysis, we further identified the SpCENP-A-localizing chaperone Sim3 as a SpCENP-A NTD interacting protein that is dependent on GRANT proline residues. Ectopic expression of sim3+ complemented the chromosome segregation defect arising from the loss of these proline residues. Overall, cis-trans proline isomerization is a post-translational modification of the SpCENP-A NTD that confers precise propagation of centromeric integrity in fission yeast, presumably via targeting SpCENP-A to the centromere.
Assuntos
Centrômero/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Cromossomos Fúngicos/metabolismo , Proteínas Nucleares/metabolismo , Prolina/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , Motivos de Aminoácidos , Centrômero/ultraestrutura , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos , Cromossomos Fúngicos/química , Teste de Complementação Genética , Instabilidade Genômica , Isomerismo , Cinética , Proteínas Nucleares/genética , Prolina/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Alinhamento de Sequência , Proteínas de Ligação a Tacrolimo/genética , Proteínas de Ligação a Tacrolimo/metabolismoRESUMO
Kinetochore fibers (K-fibers) are microtubule bundles attached to chromosomes. Efficient K-fiber formation is required for chromosome congression, crucial for faithful chromosome segregation in cells. However, the mechanisms underlying K-fiber formation before chromosome biorientation remain unclear. Depletion of hepatoma up-regulated protein (HURP), a RanGTP-dependent microtubule-associated protein localized on K-fibers, has been shown to result in low-efficiency K-fiber formation. Therefore, here we sought to identify critical interaction partners of HURP that may modulate this function. Using co-immunoprecipitation and bimolecular fluorescence complementation assays, we determined that HURP interacts directly with the centrosomal protein transforming acidic coiled coil-containing protein 3 (TACC3), a centrosomal protein, both in vivo and in vitro through the HURP1-625 region. We found that HURP is important for TACC3 function during kinetochore microtubule assembly at the chromosome region in prometaphase. Moreover, HURP regulates stable lateral kinetochore attachment and chromosome congression in early mitosis by modulation of TACC3. These findings provide new insight into the coordinated regulation of K-fiber formation and chromosome congression in prometaphase by microtubule-associated proteins.
Assuntos
Posicionamento Cromossômico , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/metabolismo , Proteínas de Neoplasias/genética , Prometáfase , Sequência de Aminoácidos , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Segregação de Cromossomos , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Cinetocoros/metabolismo , Cinetocoros/ultraestrutura , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Proteínas de Neoplasias/metabolismo , Transporte Proteico , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Fuso Acromático/metabolismo , Fuso Acromático/ultraestrutura , Imagem com Lapso de TempoRESUMO
Both EZH2 and NF-κB contribute to aggressive breast cancer, yet whether the two oncogenic factors have functional crosstalk in breast cancer is unknown. Here, we uncover an unexpected role of EZH2 in conferring the constitutive activation of NF-κB target gene expression in ER-negative basal-like breast cancer cells. This function of EZH2 is independent of its histone methyltransferase activity but requires the physical interaction with RelA/RelB to promote the expression of NF-κB targets. Intriguingly, EZH2 acts oppositely in ER-positive luminal-like breast cancer cells and represses NF-κB target gene expression by interacting with ER and directing repressive histone methylation on their promoters. Thus, EZH2 functions as a double-facet molecule in breast cancers, either as a transcriptional activator or repressor of NF-κB targets, depending on the cellular context. These findings reveal an additional mechanism by which EZH2 promotes breast cancer progression and underscore the need for developing context-specific strategy for therapeutic targeting of EZH2 in breast cancers.
Assuntos
Neoplasias da Mama/genética , Proteínas de Ligação a DNA/metabolismo , NF-kappa B/genética , Fatores de Transcrição/metabolismo , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/genética , Proteína Potenciadora do Homólogo 2 de Zeste , Feminino , Regulação Neoplásica da Expressão Gênica , Genes Reguladores , Humanos , NF-kappa B/metabolismo , Complexo Repressor Polycomb 2 , Fatores de Transcrição/genéticaRESUMO
Endoplasmic reticulum-mitochondrial contacts (EMCs) regulate multiple critical cellular activities, dysregulation of which correlates with various human maladies such as neurodegenerative diseases. A new study makes use of the ascorbate peroxidase proximity-labeling proteomics approach to scrutinize the components of EMCs in live cells, leading to the identification of reticulon 1A as a novel promoter of EMCs.
Assuntos
Retículo Endoplasmático , Mitocôndrias , Animais , Ascorbato Peroxidases , Humanos , ProteômicaRESUMO
Defective mitophagy linked to dysfunction in the proteins Parkin and PTEN-induced putative kinase 1 (PINK1) is implicated in the pathogenesis of Parkinson's disease. Although the mechanism by which Parkin mediates mitophagy in a PINK1-dependent manner is becoming clearer, the triggers for this mitophagy pathway remain elusive. Reactive oxygen species (ROS) have been suggested as such triggers, but this proposal remains controversial because ROS scavengers fail to retard mitophagy. Here we demonstrate that the role of ROS in mitophagy has been underappreciated as a result of the inefficiency of ROS scavengers to control ROS bursts after high-dose treatment with carbonyl cyanide m-chlorophenylhydrazone. Supporting this, combinatorial treatment with N-acetyl-l-cysteine and catalase substantially inhibited the ROS upsurge and PINK1-dependent Parkin translocation to mitochondria in response to carbonyl cyanide m-chlorophenylhydrazone treatment. In addition to the chemical mitophagy inducer, overexpression of voltage-dependent anion channel 1 (VDAC1) induced Parkin translocation to mitochondria, presumably by stimulating ROS generation. Similarly, combined N-acetyl-l-cysteine and catalase treatment also suppressed VDAC1-induced redistribution of Parkin. Alongside these observations, we also found that the elevated protein level of PINK1 was not necessary for Parkin translocation to mitochondria. Thus, our data suggest that ROS may act as a trigger for the induction of Parkin/PINK1-dependent mitophagy. In addition, our study casts doubt on the importance of protein quantity of PINK1 in the recruitment of Parkin to mitochondria.
Assuntos
Mitocôndrias/metabolismo , Mitofagia/fisiologia , Proteínas Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Acetilcisteína/farmacologia , Sequestradores de Radicais Livres/farmacologia , Células HeLa , Humanos , Mitocôndrias/genética , Mitofagia/efeitos dos fármacos , Proteínas Quinases/genética , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/genética , Ubiquitina-Proteína Ligases/genéticaRESUMO
Floral transition in plants is regulated by an integrated network of flowering genetic pathways. We show that an Arabidopsis PIN1-type parvulin 1, Pin1At, controls floral transition by accelerating cis/trans isomerization of the phosphorylated Ser/Thr-Pro motifs in two MADS-domain transcription factors, SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) and AGAMOUS-LIKE 24 (AGL24). Pin1At regulates flowering, which is genetically mediated by AGL24 and SOC1. Pin1At interacts with the phosphorylated AGL24 and SOC1 in vitro and with AGL24 and SOC1 in vivo and accelerates the cis/trans conformational change of phosphorylated Ser/Thr-Pro motifs of AGL24 and SOC1. We further demonstrate that these Ser/Thr-Pro motifs are important for Pin1At function in promoting flowering through AGL24 and SOC1 and that the interaction between Pin1At and AGL24 mediates the AGL24 stability in the nucleus. Taken together, we propose that phosphorylation-dependent prolyl cis/trans isomerization of key transcription factors is an important flowering regulatory mechanism.
Assuntos
Arabidopsis/enzimologia , Peptidilprolil Isomerase/fisiologia , Motivos de Aminoácidos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Flores/enzimologia , Flores/genética , Flores/crescimento & desenvolvimento , Proteínas de Domínio MADS/química , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Mutagênese Sítio-Dirigida , Peptidilprolil Isomerase de Interação com NIMA , Peptidilprolil Isomerase/genética , Peptidilprolil Isomerase/metabolismo , Fosforilação , Fotoperíodo , Estabilidade ProteicaRESUMO
BACKGROUND & AIMS: Activation of WNT signaling promotes the invasive activities of several types of cancer cells, but it is not clear if it regulates the same processes in colorectal cancer (CRC) cells, or what mechanisms are involved. We studied the expression and function of OVOL2, a member of the Ovo family of conserved zinc-finger transcription factors regulated by the WNT signaling pathway, in intestinal tumors of mice and human beings. METHODS: We analyzed the expression of OVOL2 protein and messenger RNA in CRC cell lines and tissue arrays, as well as CRC samples from patients who underwent surgery at Xiamen University in China from 2009 to 2012; clinical information also was collected. CRC cell lines (SW620) were infected with lentivirus expressing OVOL2, analyzed in migration and invasion assays, and injected into nude mice to assess tumor growth and metastasis. Tandem affinity purification was used to purify the OVOL2-containing complex from CRC cells; the complex was analyzed by liquid chromatography, tandem mass spectrometry, and immunoprecipitation experiments. Gene promoter activities were measured in luciferase reporter assays. We analyzed mice with an intestine-specific disruption of Ovol2 (Ovol2(flox/+) transgenic mice), as well as Apc(min/+) mice; these mice were crossed and analyzed. RESULTS: Analysis of data from patients indicated that the levels of OVOL2 messenger RNA were significantly lower in colon carcinomas than adenomas, and decreased significantly as carcinomas progressed from grades 2 to 4. Immunohistochemical analysis of a tissue array of 275 CRC samples showed a negative association between tumor stage and OVOL2 level. Overexpression of OVOL2 in SW620 cells decreased their migration and invasion, reduced markers of the epithelial-to-mesenchymal transition, and suppressed their metastasis as xenograft tumors in nude mice; knockdown of OVOL2 caused LS174T cells to transition from epithelial to mesenchymal phenotypes. OVOL2 bound T-cell factor (TCF)4 and ß-catenin, facilitating recruitment of histone deacetylase 1 to the TCF4-ß-catenin complex; this inhibited expression of epithelial-to-mesenchymal transition-related genes regulated by WNT, such as SLUG, in CRC cell lines. OVOL2 was a downstream target of WNT signaling in LS174T and SW480 cells. The OVOL2 promoter was hypermethylated in late-stage CRC specimens from patients and in SW620 cells; hypermethylation resulted in OVOL2 down-regulation and an inability to inhibit WNT signaling. Disruption of Ovol2 in Apc(min/+) mice increased WNT activity in intestinal tissues and the formation of invasive intestinal tumors. CONCLUSIONS: OVOL2 is a colorectal tumor suppressor that blocks WNT signaling by facilitating the recruitment of histone deacetylase 1 to the TCF4-ß-catenin complex. Strategies to increase levels of OVOL2 might be developed to reduce colorectal tumor progression and metastasis.
Assuntos
Movimento Celular , Neoplasias Colorretais/metabolismo , Fatores de Transcrição/metabolismo , Via de Sinalização Wnt , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Células CACO-2 , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Regulação para Baixo , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Genótipo , Células HCT116 , Células HEK293 , Histona Desacetilase 1/metabolismo , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Camundongos Transgênicos , Invasividade Neoplásica , Metástase Neoplásica , Fenótipo , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Fatores de Tempo , Fator de Transcrição 4 , Fatores de Transcrição/genética , Transfecção , Carga Tumoral , beta Catenina/metabolismoRESUMO
Mitochondrial morphologies change over time and are tightly regulated by dynamic machinery proteins such as dynamin-related protein 1 (Drp1), mitofusion 1/2, and optic atrophy 1 (OPA1). However, the detailed mechanisms of how these molecules cooperate to mediate fission and fusion remain elusive. DAP3 is a mitochondrial ribosomal protein that involves in apoptosis, but its biological function has not been well characterized. Here, we demonstrate that DAP3 specifically localizes in the mitochondrial matrix. Knockdown of DAP3 in mitochondria leads to defects in mitochondrial-encoded protein synthesis and abnormal mitochondrial dynamics. Moreover, depletion of DAP3 dramatically decreases the phosphorylation of Drp1 at Ser-637 on mitochondria, enhancing the retention time of Drp1 puncta on mitochondria during the fission process. Furthermore, autophagy is inhibited in the DAP3-depleted cells, which sensitizes cells to different types of death stimuli. Together, our results suggest that DAP3 plays important roles in mitochondrial function and dynamics, providing new insights into the mechanism of a mitochondrial ribosomal protein function in cell death.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial , Biossíntese de Proteínas , Proteínas Ribossômicas/metabolismo , Animais , Proteínas Reguladoras de Apoptose/deficiência , Proteínas Reguladoras de Apoptose/genética , Autofagia , Linhagem Celular , Dinaminas/química , Dinaminas/metabolismo , Técnicas de Silenciamento de Genes , Técnicas de Inativação de Genes , Homeostase , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Proteínas Mitocondriais/metabolismo , Fosforilação , Transporte Proteico , RNA Interferente Pequeno/genética , Proteínas de Ligação a RNA , Proteínas Ribossômicas/deficiência , Proteínas Ribossômicas/genética , Serina/metabolismoRESUMO
Pruning that selectively eliminates unnecessary axons/dendrites is crucial for sculpting the nervous system during development. During Drosophila metamorphosis, dendrite arborization neurons, ddaCs, selectively prune their larval dendrites in response to the steroid hormone ecdysone, whereas mushroom body γ neurons specifically eliminate their axon branches within dorsal and medial lobes. However, it is unknown which E3 ligase directs these two modes of pruning. Here, we identified a conserved SCF E3 ubiquitin ligase that plays a critical role in pruning of both ddaC dendrites and mushroom body γ axons. The SCF E3 ligase consists of four core components Cullin1/Roc1a/SkpA/Slimb and promotes ddaC dendrite pruning downstream of EcR-B1 and Sox14, but independently of Mical. Moreover, we demonstrate that the Cullin1-based E3 ligase facilitates ddaC dendrite pruning primarily through inactivation of the InR/PI3K/TOR pathway. We show that the F-box protein Slimb forms a complex with Akt, an activator of the InR/PI3K/TOR pathway, and promotes Akt ubiquitination. Activation of the InR/PI3K/TOR pathway is sufficient to inhibit ddaC dendrite pruning. Thus, our findings provide a novel link between the E3 ligase and the InR/PI3K/TOR pathway during dendrite pruning.
Assuntos
Proteínas Culina/metabolismo , Proteínas de Drosophila/metabolismo , Sistema Nervoso/embriologia , Fosfatidilinositol 3-Quinases/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Proteínas de Ligação ao Cálcio , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Culina/genética , Proteínas de Ligação a DNA/genética , Dendritos/metabolismo , Drosophila/embriologia , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Ecdisona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Metamorfose Biológica , Corpos Pedunculados/inervação , Neurônios/metabolismo , Proteínas Nucleares , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Interferente Pequeno , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Fatores de Transcrição SOXB2/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Pin1 is a highly conserved enzyme that only isomerizes specific phosphorylated Ser/Thr-Pro bonds in certain proteins, thereby inducing conformational changes. Such conformational changes represent a novel and tightly controlled signaling mechanism regulating a spectrum of protein activities in physiology and disease; often through phosphorylation-dependent, ubiquitin-mediated proteasomal degradation. In this review, we summarize recent advances in elucidating the role and regulation of Pin1 in controlling protein stability. We also propose a mechanism by which Pin1 functions as a molecular switch to control the fates of phosphoproteins. We finally stress the need to develop tools to visualize directly Pin1-catalyzed protein conformational changes as a way to determine their roles in the development and treatment of human diseases.
Assuntos
Peptidilprolil Isomerase/metabolismo , Fosfoproteínas/metabolismo , Envelhecimento , Expressão Gênica , Humanos , Peptidilprolil Isomerase de Interação com NIMA , Neoplasias/metabolismo , Doenças Neurodegenerativas/metabolismo , Peptidilprolil Isomerase/genética , Fosfoproteínas/química , Conformação Proteica , Estabilidade Proteica , Proteólise , Telômero/metabolismoRESUMO
Pin1 was the first prolyl isomerase identified that is involved in cell division. The mechanism by which Pin1 acts as a negative regulator of mitotic activity in G2 phase remains unclear. Here, we found that Aurora A can interact with and phosphorylate Pin1 at Ser16, which suppresses the G2/M function of Pin1 by disrupting its binding ability and mitotic entry. Our results also show that phosphorylation of Bora at Ser274 and Ser278 is crucial for binding of Pin1. Through the interaction, Pin1 can alter the cytoplasmic translocation of Bora and promote premature degradation by ß-TrCP, which results in a delay in mitotic entry. Together with the results that Pin1 protein levels do not significantly fluctuate during cell-cycle progression and Aurora A suppresses Pin1 G2/M function, our data demonstrate that a gain of Pin1 function can override the Aurora-A-mediated functional suppression of Pin1. Collectively, these results highlight the physiological significance of Aurora-A-mediated Pin1 Ser16 phosphorylation for mitotic entry and the suppression of Pin1 is functionally linked to the regulation of mitotic entry through the Aurora-A-Bora complex.
Assuntos
Aurora Quinase A/metabolismo , Proteínas de Ciclo Celular/metabolismo , Células/citologia , Fase G2 , Mitose , Peptidilprolil Isomerase/metabolismo , Motivos de Aminoácidos , Animais , Aurora Quinase A/genética , Proteínas de Ciclo Celular/genética , Células/enzimologia , Células/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Knockout , Peptidilprolil Isomerase de Interação com NIMA , Peptidilprolil Isomerase/genética , Fosforilação , Ligação ProteicaRESUMO
Osteoporosis, a metabolic bone disease characterized by low bone mineral density and deterioration of bone microarchitecture, has led to a high risk of fatal osteoporotic fractures worldwide. Accumulating evidence has revealed that sexual dimorphism is a notable feature of osteoporosis, with sex-specific differences in epidemiology and pathogenesis. Specifically, females are more susceptible than males to osteoporosis, while males are more prone to disability or death from the disease. To date, sex chromosome abnormalities and steroid hormones have been proven to contribute greatly to sexual dimorphism in osteoporosis by regulating the functions of bone cells. Understanding the sex-specific differences in osteoporosis and its related complications is essential for improving treatment strategies tailored to women and men. This literature review focuses on the mechanisms underlying sexual dimorphism in osteoporosis, mainly in a population of aging patients, chronic glucocorticoid administration, and diabetes. Moreover, we highlight the implications of sexual dimorphism for developing therapeutics and preventive strategies and screening approaches tailored to women and men. Additionally, the challenges in translating bench research to bedside treatments and future directions to overcome these obstacles will be discussed.
Assuntos
Doenças Ósseas Metabólicas , Osteoporose , Fraturas por Osteoporose , Masculino , Humanos , Feminino , Caracteres Sexuais , Densidade Óssea , Osteoporose/epidemiologia , Fraturas por Osteoporose/complicações , Doenças Ósseas Metabólicas/complicaçõesRESUMO
Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.
RESUMO
BRAF V600E attracts wide attention in the treatment of colorectal cancer (CRC) as stratifying and predicting a refractory classification of CRC. Recent evidence indicates that Wnt/ß-catenin signaling is broadly activated and participates in the refractoriness of BRAF V600E CRC, but the underlying molecular mechanism needs to be elucidated. Here, heat shock 70 kDa protein 8 (HSPA8), an essential regulator in chaperone-mediated autophagy (CMA), is identified as a potential therapeutic target for advanced BRAF V600E CRC. These results show that HSPA8 is transcriptionally upregulated in BRAF V600E CRC, which promotes CMA-dependent degradation of caveolin-1 (CAV1) to release ß-catenin into the nucleus and thus activates the Wnt/ß-catenin pathway, contributing to metastasis and progression of BRAF V600E CRC. Of note, HSPA8 directly interacts with the KIFSN motif on CAV1, the interaction can be enhanced by p38 MAPK-mediated CAV1 S168 phosphorylation. Furthermore, pharmacological targeting HSPA8 by VER155008 exhibits synergistic effects with BRAF inhibitors on CRC mouse models. In summary, these findings discover the important role of the HSPA8/CAV1/ß-catenin axis in the development of refractory BRAF V600E CRC and highlight HSPA8 as a predictive biomarker and therapeutic target in clinical practice.
Assuntos
Autofagia Mediada por Chaperonas , Neoplasias Colorretais , Animais , Camundongos , beta Catenina/metabolismo , Caveolina 1/genética , Caveolina 1/metabolismo , Caveolina 1/uso terapêutico , Neoplasias Colorretais/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas B-raf/uso terapêuticoRESUMO
Burn injuries are a significant cause of death worldwide, leading to systemic inflammation, multiple organ failure and sepsis. The progression of burn injury is explicitly correlated with mitochondrial homeostasis, which is disrupted by the hyperinflammation induced by burn injury, leading to mitochondrial dysfunction and cell death. Mitophagy plays a crucial role in maintaining cellular homeostasis by selectively removing damaged mitochondria. A growing body of evidence from various disease models suggest that pharmacological interventions targeting mitophagy could be a promising therapeutic strategy. Recent studies have shown that mitophagy plays a crucial role in wound healing and burn injury. Furthermore, chemicals targeting mitophagy have also been shown to improve wound recovery, highlighting the potential for novel therapeutic strategies based on an in-depth exploration of the molecular mechanisms regulating mitophagy and its association with skin wound healing.
RESUMO
The peptidyl prolyl cis-trans isomerase Pin1 plays vital roles in diverse cellular processes and pathological conditions. NeuroD is a differentiation and survival factor for a subset of neurons and pancreatic endocrine cells. Although multiple phosphorylation events are known to be crucial for NeuroD function, their mechanisms remain elusive. In this study, we demonstrate that zebrafish embryos deficient in Pin1 displayed phenotypes resembling those associated with NeuroD depletion, characterized by defects in formation of mechanosensory hair cells. Furthermore, zebrafish Pin1 interacts with NeuroD in a phosphorylation-dependent manner. In Pin1-deficient cell lines, NeuroD is rapidly degraded. However, the protein stability of NeuroD is restored upon overexpression of Pin1. These findings suggest that Pin1 functionally regulates NeuroD protein levels by post-phosphorylation cis-trans isomerization during neuronal specification.
RESUMO
Nucleolar and spindle-associated protein 1 (NUSAP1) is a microtubule-associated protein that plays a crucial role in mitosis. Despite initial reports suggesting a potential involvement of NUSAP1 in tumor progression and malignant cell regulation, there has been no systematic analysis of its role in the tumor immune microenvironment, nor its predictive value for prognosis and immunotherapy response across different cancer types. In this study, we analyze NUSAP1 mRNA and protein expression levels in various human normal and tumor tissues, using data from TCGA, GTEx, CPTAC, HPA databases, and clinical samples. Our findings reveal that NUSAP1 is highly expressed in multiple tumor tissues across most cancer types and is primarily expressed in malignant and immune cells, according to single-cell sequencing data from the TISCH database. Prognostic analysis based on curated survival data from the TCGA database indicates that NUSAP1 expression levels can predict clinical outcomes for 26 cancer types. Furthermore, Gene Set Enrichment Analysis (GSEA) suggests that NUSAP1 promotes cell proliferation, tumor cell invasion, and regulation of anti-tumor response. Analysis of immune score, immune cell infiltration, and anti-cancer immunity cycle using ESTIMATE, TIMER, and TIP databases show that high NUSAP1 levels are associated with low CD4+T and NKT cell infiltration but high Th2 and MDSC infiltration, inversely correlated with antigen-presenting molecules and positively correlated with a variety of immune negative regulatory molecules. Notably, patients with melanoma, lung, and kidney cancer with high NUSAP1 expression levels have shorter survival times and lower immunotherapy response rates. Using Cmap analysis, we identify Entinostat and AACOCF3 as potential inhibitors of NUSAP1-mediated pro-oncogenic effects. In vitro and in vivo experiments further confirm that NUSAP1 knockdown significantly reduces the proliferation ability of A549 and MCF-7 cells. Overall, our study highlights the potential of NUSAP1 expression as a novel biomarker for predicting prognosis and immuno-therapeutic efficacy across different human cancers and suggests its potential for developing novel antitumor drugs or improving immunotherapy.