Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
1.
Cell ; 158(3): 633-46, 2014 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-25083873

RESUMO

ATR controls chromosome integrity and chromatin dynamics. We have previously shown that yeast Mec1/ATR promotes chromatin detachment from the nuclear envelope to counteract aberrant topological transitions during DNA replication. Here, we provide evidence that ATR activity at the nuclear envelope responds to mechanical stress. Human ATR associates with the nuclear envelope during S phase and prophase, and both osmotic stress and mechanical stretching relocalize ATR to nuclear membranes throughout the cell cycle. The ATR-mediated mechanical response occurs within the range of physiological forces, is reversible, and is independent of DNA damage signaling. ATR-defective cells exhibit aberrant chromatin condensation and nuclear envelope breakdown. We propose that mechanical forces derived from chromosome dynamics and torsional stress on nuclear membranes activate ATR to modulate nuclear envelope plasticity and chromatin association to the nuclear envelope, thus enabling cells to cope with the mechanical strain imposed by these molecular processes.


Assuntos
Membrana Nuclear/metabolismo , Estresse Mecânico , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Cromatina/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HeLa , Humanos , Camundongos , Células NIH 3T3 , Osmose , Proteínas Quinases/metabolismo
2.
Proc Natl Acad Sci U S A ; 121(29): e2404551121, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38990945

RESUMO

Confined cell migration hampers genome integrity and activates the ATR and ATM mechano-transduction pathways. We investigated whether the mechanical stress generated by metastatic interstitial migration contributes to the enhanced chromosomal instability observed in metastatic tumor cells. We employed live cell imaging, micro-fluidic approaches, and scRNA-seq to follow the fate of tumor cells experiencing confined migration. We found that, despite functional ATR, ATM, and spindle assembly checkpoint (SAC) pathways, tumor cells dividing across constriction frequently exhibited altered spindle pole organization, chromosome mis-segregations, micronuclei formation, chromosome fragility, high gene copy number variation, and transcriptional de-regulation and up-regulation of c-MYC oncogenic transcriptional signature via c-MYC locus amplifications. In vivo tumor settings showed that malignant cells populating metastatic foci or infiltrating the interstitial stroma gave rise to cells expressing high levels of c-MYC. Altogether, our data suggest that mechanical stress during metastatic migration contributes to override the checkpoint controls and boosts genotoxic and oncogenic events. Our findings may explain why cancer aneuploidy often does not correlate with mutations in SAC genes and why c-MYC amplification is strongly linked to metastatic tumors.


Assuntos
Movimento Celular , Amplificação de Genes , Proteínas Proto-Oncogênicas c-myc , Estresse Mecânico , Humanos , Movimento Celular/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Animais , Linhagem Celular Tumoral , Camundongos , Mitose/genética , Instabilidade Cromossômica , Regulação Neoplásica da Expressão Gênica , Neoplasias/genética , Neoplasias/patologia , Neoplasias/metabolismo
3.
EMBO J ; 41(22): e108040, 2022 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-36215697

RESUMO

The ribonuclease DIS3 is one of the most frequently mutated genes in the hematological cancer multiple myeloma, yet the basis of its tumor suppressor function in this disease remains unclear. Herein, exploiting the TCGA dataset, we found that DIS3 plays a prominent role in the DNA damage response. DIS3 inactivation causes genomic instability by increasing mutational load, and a pervasive accumulation of DNA:RNA hybrids that induces genomic DNA double-strand breaks (DSBs). DNA:RNA hybrid accumulation also prevents binding of the homologous recombination (HR) machinery to double-strand breaks, hampering DSB repair. DIS3-inactivated cells become sensitive to PARP inhibitors, suggestive of a defect in homologous recombination repair. Accordingly, multiple myeloma patient cells mutated for DIS3 harbor an increased mutational burden and a pervasive overexpression of pro-inflammatory interferon, correlating with the accumulation of DNA:RNA hybrids. We propose DIS3 loss in myeloma to be a driving force for tumorigenesis via DNA:RNA hybrid-dependent enhanced genome instability and increased mutational rate. At the same time, DIS3 loss represents a liability that might be therapeutically exploited in patients whose cancer cells harbor DIS3 mutations.


Assuntos
Mieloma Múltiplo , Humanos , Mieloma Múltiplo/genética , Mieloma Múltiplo/patologia , Ribonucleases/metabolismo , Reparo de DNA por Recombinação , Recombinação Homóloga , Instabilidade Genômica , Reparo do DNA , DNA/metabolismo , RNA , Complexo Multienzimático de Ribonucleases do Exossomo/metabolismo
4.
Small ; 18(17): e2106097, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35344274

RESUMO

Circulating tumor cell (CTC) clusters are associated with increased metastatic potential and worse patient prognosis, but are rare, difficult to count, and poorly characterized biophysically. The PillarX device described here is a bimodular microfluidic device (Pillar-device and an X-magnetic device) to profile single CTCs and clusters from whole blood based on their size, deformability, and epithelial marker expression. Larger, less deformable clusters and large single cells are captured in the Pillar-device and sorted according to pillar gap sizes. Smaller, deformable clusters and single cells are subsequently captured in the X-device and separated based on epithelial marker expression using functionalized magnetic nanoparticles. Clusters of established and primary breast cancer cells with variable degrees of cohesion driven by different cell-cell adhesion protein expression are profiled in the device. Cohesive clusters exhibit a lower deformability as they travel through the pillar array, relative to less cohesive clusters, and have greater collective invasive behavior. The ability of the PillarX device to capture clusters is validated in mouse models and patients of metastatic breast cancer. Thus, this device effectively enumerates and profiles CTC clusters based on their unique geometrical, physical, and biochemical properties, and could form the basis of a novel prognostic clinical tool.


Assuntos
Neoplasias da Mama , Células Neoplásicas Circulantes , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Separação Celular , Feminino , Humanos , Dispositivos Lab-On-A-Chip , Camundongos , Células Neoplásicas Circulantes/patologia , Prognóstico
5.
Nat Mater ; 18(11): 1252-1263, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31332337

RESUMO

During wound repair, branching morphogenesis and carcinoma dissemination, cellular rearrangements are fostered by a solid-to-liquid transition, known as unjamming. The biomolecular machinery behind unjamming and its pathophysiological relevance remain, however, unclear. Here, we study unjamming in a variety of normal and tumorigenic epithelial two-dimensional (2D) and 3D collectives. Biologically, the increased level of the small GTPase RAB5A sparks unjamming by promoting non-clathrin-dependent internalization of epidermal growth factor receptor that leads to hyperactivation of the kinase ERK1/2 and phosphorylation of the actin nucleator WAVE2. This cascade triggers collective motility effects with striking biophysical consequences. Specifically, unjamming in tumour spheroids is accompanied by persistent and coordinated rotations that progressively remodel the extracellular matrix, while simultaneously fluidizing cells at the periphery. This concurrent action results in collective invasion, supporting the concept that the endo-ERK1/2 pathway is a physicochemical switch to initiate collective invasion and dissemination of otherwise jammed carcinoma.


Assuntos
Diferenciação Celular , Movimento Celular , Linhagem Celular Tumoral , Proliferação de Células , Receptores ErbB/metabolismo , Humanos , Cinética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Proteínas rab5 de Ligação ao GTP/metabolismo
6.
Hepatology ; 69(1): 376-393, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30033593

RESUMO

Therapeutic options for patients with advanced-stage hepatocellular carcinoma (HCC) are very limited. The only approved first-line treatment is the multi-tyrosine kinase inhibitor sorafenib, which shows low response rates and severe side effects. In particular, the compensatory activation of growth factor receptors leads to chemoresistance and limits the clinical impact of sorafenib. However, combination approaches to improve sorafenib have failed. Here we investigate the inhibition of cyclin-dependent kinase 5 (Cdk5) as a promising combination strategy to improve sorafenib response in HCC. Combination of sorafenib with Cdk5 inhibition (genetic knockdown by short hairpin RNA or CRISPR/Cas9 and pharmacologic inhibition) synergistically impaired HCC progression in vitro and in vivo by inhibiting both tumor cell proliferation and migration. Importantly, these effects were mediated by a mechanism for Cdk5: A liquid chromatography-tandem mass spectrometry-based proteomic approach revealed that Cdk5 inhibition interferes with intracellular trafficking, a process crucial for cellular homeostasis and growth factor receptor signaling. Cdk5 inhibition resulted in an accumulation of enlarged vesicles and respective cargos in the perinuclear region, considerably impairing the extent and quality of growth factor receptor signaling. Thereby, Cdk5 inhibition offers a comprehensive approach to globally disturb growth factor receptor signaling that is superior to specific inhibition of individual growth factor receptors. Conclusion: Cdk5 inhibition represents an effective approach to improve sorafenib response and to prevent sorafenib treatment escape in HCC. Notably, Cdk5 is an addressable target frequently overexpressed in HCC, and with Dinaciclib, a clinically tested Cdk5 inhibitor is readily available. Thus, our study provides evidence for clinically evaluating the combination of sorafenib and Dinaciclib to improve the therapeutic situation for patients with advanced-stage HCC.


Assuntos
Carcinoma Hepatocelular/tratamento farmacológico , Quinase 5 Dependente de Ciclina/antagonistas & inibidores , Neoplasias Hepáticas/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Sorafenibe/uso terapêutico , Animais , Feminino , Humanos , Camundongos , Resultado do Tratamento , Células Tumorais Cultivadas
7.
J Exp Biol ; 222(Pt 19)2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31527179

RESUMO

Spontaneous nerve regeneration in cephalopod molluscs occurs in a relative short time after injury, achieving functional recovery of lost capacity. In particular, transection of the pallial nerve in the common octopus (Octopus vulgaris) determines the loss and subsequent restoration of two functions fundamental for survival, i.e. breathing and skin patterning, the latter involved in communication between animals and concealment. The phenomena occurring after lesion have been investigated in a series of previous studies, but a complete analysis of the changes taking place at the level of the axons and the effects on the animals' appearance during the whole regenerative process is still missing. Our goal was to determine the course of events following injury, from impairment to full recovery. Through imaging of the traced damaged nerves, we were able to characterize the pathways followed by fibres during regeneration and end-target re-innervation, while electrophysiology and behavioural observations highlighted the regaining of functional connections between the central brain and periphery, using the contralateral nerve in the same animal as an internal control. The final architecture of a fully regenerated pallial nerve does not exactly mirror the original structure; however, functionality returns to match the phenotype of an intact octopus with no observable impact on the behaviour of the animal. Our findings provide new important scenarios for the study of regeneration in cephalopods and highlight the octopus pallial nerve as a valuable 'model' among invertebrates.


Assuntos
Regeneração Nervosa/fisiologia , Tecido Nervoso/lesões , Tecido Nervoso/fisiopatologia , Octopodiformes/fisiologia , Recuperação de Função Fisiológica/fisiologia , Animais , Axônios/fisiologia , Comportamento Animal , Fenômenos Eletrofisiológicos , Feminino , Masculino , Octopodiformes/anatomia & histologia , Respiração , Pele/inervação
9.
Nat Mater ; 16(5): 587-596, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28135264

RESUMO

Dynamics of epithelial monolayers has recently been interpreted in terms of a jamming or rigidity transition. How cells control such phase transitions is, however, unknown. Here we show that RAB5A, a key endocytic protein, is sufficient to induce large-scale, coordinated motility over tens of cells, and ballistic motion in otherwise kinetically arrested monolayers. This is linked to increased traction forces and to the extension of cell protrusions, which align with local velocity. Molecularly, impairing endocytosis, macropinocytosis or increasing fluid efflux abrogates RAB5A-induced collective motility. A simple model based on mechanical junctional tension and an active cell reorientation mechanism for the velocity of self-propelled cells identifies regimes of monolayer dynamics that explain endocytic reawakening of locomotion in terms of a combination of large-scale directed migration and local unjamming. These changes in multicellular dynamics enable collectives to migrate under physical constraints and may be exploited by tumours for interstitial dissemination.


Assuntos
Endocitose , Epitélio/metabolismo , Fenômenos Biomecânicos , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Humanos , Proteínas rab5 de Ligação ao GTP/metabolismo
11.
Nature ; 471(7336): 74-79, 2011 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-21368826

RESUMO

Protein acetylation is mediated by histone acetyltransferases (HATs) and deacetylases (HDACs), which influence chromatin dynamics, protein turnover and the DNA damage response. ATM and ATR mediate DNA damage checkpoints by sensing double-strand breaks and single-strand-DNA-RFA nucleofilaments, respectively. However, it is unclear how acetylation modulates the DNA damage response. Here we show that HDAC inhibition/ablation specifically counteracts yeast Mec1 (orthologue of human ATR) activation, double-strand-break processing and single-strand-DNA-RFA nucleofilament formation. Moreover, the recombination protein Sae2 (human CtIP) is acetylated and degraded after HDAC inhibition. Two HDACs, Hda1 and Rpd3, and one HAT, Gcn5, have key roles in these processes. We also find that HDAC inhibition triggers Sae2 degradation by promoting autophagy that affects the DNA damage sensitivity of hda1 and rpd3 mutants. Rapamycin, which stimulates autophagy by inhibiting Tor, also causes Sae2 degradation. We propose that Rpd3, Hda1 and Gcn5 control chromosome stability by coordinating the ATR checkpoint and double-strand-break processing with autophagy.


Assuntos
Autofagia , Quebras de DNA de Cadeia Dupla , Histona Desacetilases/metabolismo , Saccharomyces cerevisiae , Acetilação/efeitos dos fármacos , Aminopeptidases/metabolismo , Autofagia/efeitos dos fármacos , Família da Proteína 8 Relacionada à Autofagia , Proteínas Relacionadas à Autofagia , Instabilidade Cromossômica , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Endodesoxirribonucleases/metabolismo , Endonucleases/química , Endonucleases/metabolismo , Exodesoxirribonucleases/metabolismo , Histona Acetiltransferases/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Quinases/genética , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/antagonistas & inibidores , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Transdução de Sinais/efeitos dos fármacos , Ácido Valproico/farmacologia
12.
Nat Commun ; 15(1): 7100, 2024 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-39155303

RESUMO

The identification of genes involved in replicative stress is key to understanding cancer evolution and to identify therapeutic targets. Here, we show that CDK12 prevents transcription-replication conflicts (TRCs) and the activation of cytotoxic replicative stress upon deregulation of the MYC oncogene. CDK12 was recruited at damaged genes by PARP-dependent DDR-signaling and elongation-competent RNAPII, to repress transcription. Either loss or chemical inhibition of CDK12 led to DDR-resistant transcription of damaged genes. Loss of CDK12 exacerbated TRCs in MYC-overexpressing cells and led to the accumulation of double-strand DNA breaks, occurring between co-directional early-replicating regions and transcribed genes. Overall, our data demonstrate that CDK12 protects genome integrity by repressing transcription of damaged genes, which is required for proper resolution of DSBs at oncogene-induced TRCs. This provides a rationale that explains both how CDK12 deficiency can promote tandem duplications of early-replicated regions during tumor evolution, and how CDK12 targeting can exacerbate replicative-stress in tumors.


Assuntos
Quinases Ciclina-Dependentes , Replicação do DNA , Transcrição Gênica , Humanos , Quinases Ciclina-Dependentes/metabolismo , Quinases Ciclina-Dependentes/genética , Quebras de DNA de Cadeia Dupla , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Linhagem Celular Tumoral , RNA Polimerase II/metabolismo , RNA Polimerase II/genética , Dano ao DNA
13.
Science ; 385(6712): eadj7446, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39208097

RESUMO

Chromosomal instability (CIN) generates micronuclei-aberrant extranuclear structures that catalyze the acquisition of complex chromosomal rearrangements present in cancer. Micronuclei are characterized by persistent DNA damage and catastrophic nuclear envelope collapse, which exposes DNA to the cytoplasm. We found that the autophagic receptor p62/SQSTM1 modulates micronuclear stability, influencing chromosome fragmentation and rearrangements. Mechanistically, proximity of micronuclei to mitochondria led to oxidation-driven homo-oligomerization of p62, limiting endosomal sorting complex required for transport (ESCRT)-dependent micronuclear envelope repair by triggering autophagic degradation. We also found that p62 levels correlate with increased chromothripsis across human cancer cell lines and with increased CIN in colorectal tumors. Thus, p62 acts as a regulator of micronuclei and may serve as a prognostic marker for tumors with high CIN.


Assuntos
Autofagia , Instabilidade Cromossômica , Cromotripsia , Neoplasias Colorretais , Micronúcleos com Defeito Cromossômico , Proteína Sequestossoma-1 , Humanos , Proteína Sequestossoma-1/metabolismo , Proteína Sequestossoma-1/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Colorretais/metabolismo , Linhagem Celular Tumoral , Dano ao DNA , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Mitocôndrias/metabolismo , Mitocôndrias/genética , Membrana Nuclear/metabolismo
14.
Sci Adv ; 9(37): eadh4184, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37713487

RESUMO

Cancers feature substantial intratumoral heterogeneity of genetic and phenotypically distinct lineages. Although interactions between coexisting lineages are emerging as a potential contributor to tumor evolution, the extent and nature of these interactions remain largely unknown. We postulated that tumors develop ecological interactions that sustain diversity and facilitate metastasis. Using a combination of fluorescent barcoding, mathematical modeling, metabolic analysis, and in vivo models, we show that the Allee effect, i.e., growth dependency on population size, is a feature of tumor lineages and that cooperative ecological interactions between lineages alleviate the Allee barriers to growth in a model of triple-negative breast cancer. Soluble metabolite exchange formed the basis for these cooperative interactions and catalyzed the establishment of a polyclonal community that displayed enhanced metastatic dissemination and outgrowth in xenograft models. Our results highlight interclonal metabolite exchange as a key modulator of tumor ecology and a contributing factor to overcoming Allee effect-associated growth barriers to metastasis.


Assuntos
Corantes , Neoplasias de Mama Triplo Negativas , Humanos , Animais , Modelos Animais de Doenças , Densidade Demográfica
15.
Nat Commun ; 14(1): 7086, 2023 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-37925537

RESUMO

Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism activated in ~10-15% of cancers, characterized by telomeric damage. Telomeric damage-induced long non-coding RNAs (dilncRNAs) are transcribed at dysfunctional telomeres and contribute to telomeric DNA damage response (DDR) activation and repair. Here we observed that telomeric dilncRNAs are preferentially elevated in ALT cells. Inhibition of C-rich (teloC) dilncRNAs with antisense oligonucleotides leads to DNA replication stress responses, increased genomic instability, and apoptosis induction selectively in ALT cells. Cell death is dependent on DNA replication and is increased by DNA replication stress. Mechanistically, teloC dilncRNA inhibition reduces RAD51 and 53BP1 recruitment to telomeres, boosts the engagement of BIR machinery, and increases C-circles and telomeric sister chromatid exchanges, without increasing telomeric non-S phase synthesis. These results indicate that teloC dilncRNA is necessary for a coordinated recruitment of DDR factors to ALT telomeres and it is essential for ALT cancer cells survival.


Assuntos
Telomerase , Homeostase do Telômero , Homeostase do Telômero/genética , Replicação do DNA , RNA , Sobrevivência Celular/genética , Telômero/genética , Telômero/metabolismo , Telomerase/genética , Telomerase/metabolismo
16.
J Mol Cell Biol ; 14(11)2023 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-36460033

RESUMO

Peritoneal metastases (PM) from colorectal cancer (CRC) are associated with poor survival. The extracellular matrix (ECM) plays a fundamental role in modulating the homing of CRC metastases to the peritoneum. The mechanisms underlying the interactions between metastatic cells and the ECM, however, remain poorly understood, and the number of in vitro models available for the study of the peritoneal metastatic process is limited. Here, we show that decellularized ECM of the peritoneal cavity allows the growth of organoids obtained from PM, favoring the development of three-dimensional (3D) nodules that maintain the characteristics of in vivo PM. Organoids preferentially grow on scaffolds obtained from neoplastic peritoneum, which are characterized by greater stiffness than normal scaffolds. A gene expression analysis of organoids grown on different substrates reflected faithfully the clinical and biological characteristics of the organoids. An impact of the ECM on the response to standard chemotherapy treatment for PM was also observed. The ex vivo 3D model, obtained by combining patient-derived decellularized ECM with organoids to mimic the metastatic niche, could be an innovative tool to develop new therapeutic strategies in a biologically relevant context to personalize treatments.


Assuntos
Neoplasias Colorretais , Neoplasias Peritoneais , Humanos , Matriz Extracelular Descelularizada , Peritônio , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/secundário , Neoplasias Peritoneais/terapia , Organoides , Neoplasias Colorretais/metabolismo
17.
Nat Commun ; 12(1): 5488, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34531401

RESUMO

Specialised ribonucleoprotein (RNP) granules are a hallmark of polarized cells, like neurons and germ cells. Among their main functions is the spatial and temporal modulation of the activity of specific mRNA transcripts that allow specification of primary embryonic axes. While RNPs composition and role are well established, their regulation is poorly defined. Here, we demonstrate that Hecw, a newly identified Drosophila ubiquitin ligase, is a key modulator of RNPs in oogenesis and neurons. Hecw depletion leads to the formation of enlarged granules that transition from a liquid to a gel-like state. Loss of Hecw activity results in defective oogenesis, premature aging and climbing defects associated with neuronal loss. At the molecular level, reduced ubiquitination of the Fmrp impairs its translational repressor activity, resulting in altered Orb expression in nurse cells and Profilin in neurons.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Neurogênese/genética , Oogênese/genética , Ribonucleoproteínas/genética , Ubiquitina-Proteína Ligases/genética , Animais , Grânulos Citoplasmáticos/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/crescimento & desenvolvimento , Drosophila melanogaster/metabolismo , Embrião não Mamífero , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Homeostase/genética , Longevidade/genética , Neurônios/citologia , Neurônios/metabolismo , Oócitos/citologia , Oócitos/metabolismo , Transição de Fase , Profilinas/genética , Profilinas/metabolismo , Biossíntese de Proteínas , Processamento de Proteína Pós-Traducional , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Ribonucleoproteínas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
18.
Sci Signal ; 14(676)2021 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785611

RESUMO

Innate immune responses to Gram-negative bacteria depend on the recognition of lipopolysaccharide (LPS) by a receptor complex that includes CD14 and TLR4. In dendritic cells (DCs), CD14 enhances the activation not only of TLR4 but also that of the NFAT family of transcription factors, which suppresses cell survival and promotes the production of inflammatory mediators. NFAT activation requires Ca2+ mobilization. In DCs, Ca2+ mobilization in response to LPS depends on phospholipase C γ2 (PLCγ2), which produces inositol 1,4,5-trisphosphate (IP3). Here, we showed that the IP3 receptor 3 (IP3R3) and ITPKB, a kinase that converts IP3 to inositol 1,3,4,5-tetrakisphosphate (IP4), were both necessary for Ca2+ mobilization and NFAT activation in mouse and human DCs. A pool of IP3R3 was located on the plasma membrane of DCs, where it colocalized with CD14 and ITPKB. Upon LPS binding to CD14, ITPKB was required for Ca2+ mobilization through plasma membrane-localized IP3R3 and for NFAT nuclear translocation. Pharmacological inhibition of ITPKB in mice reduced both LPS-induced tissue swelling and the severity of inflammatory arthritis to a similar extent as that induced by the inhibition of NFAT using nanoparticles that delivered an NFAT-inhibiting peptide specifically to phagocytic cells. Our results suggest that ITPKB may represent a promising target for anti-inflammatory therapies that aim to inhibit specific DC functions.


Assuntos
Cálcio/metabolismo , Células Dendríticas , Fosfotransferases (Aceptor do Grupo Álcool) , Animais , Lipopolissacarídeos , Camundongos , Fosfotransferases (Aceptor do Grupo Álcool)/genética
19.
Nat Commun ; 11(1): 1345, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32165637

RESUMO

In several metazoans, the number of active replication origins in embryonic nuclei is higher than in somatic ones, ensuring rapid genome duplication during synchronous embryonic cell divisions. High replication origin density can be restored by somatic nuclear reprogramming. However, mechanisms underlying high replication origin density formation coupled to rapid cell cycles are poorly understood. Here, using Xenopus laevis, we show that SSRP1 stimulates replication origin assembly on somatic chromatin by promoting eviction of histone H1 through its N-terminal domain. Histone H1 removal derepresses ORC and MCM chromatin binding, allowing efficient replication origin assembly. SSRP1 protein decays at mid-blastula transition (MBT) when asynchronous somatic cell cycles start. Increasing levels of SSRP1 delay MBT and, surprisingly, accelerate post-MBT cell cycle speed and embryo development. These findings identify a major epigenetic mechanism regulating DNA replication and directly linking replication origin assembly, cell cycle duration and embryo development in vertebrates.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Histonas/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus laevis/genética , Xenopus laevis/metabolismo , Animais , Blástula/embriologia , Blástula/metabolismo , Cromatina/genética , Cromatina/metabolismo , Replicação do DNA , Proteínas de Ligação a DNA/genética , Proteínas de Grupo de Alta Mobilidade , Histonas/química , Histonas/genética , Domínios Proteicos , Origem de Replicação , Proteínas de Xenopus/genética , Xenopus laevis/embriologia
20.
Cell Death Differ ; 27(8): 2383-2401, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32042098

RESUMO

Mitochondria change distribution across cells following a variety of pathophysiological stimuli. The mechanisms presiding over this redistribution are yet undefined. In a murine model overexpressing Drp1 specifically in skeletal muscle, we find marked mitochondria repositioning in muscle fibres and we demonstrate that Drp1 is involved in this process. Drp1 binds KLC1 and enhances microtubule-dependent transport of mitochondria. Drp1-KLC1 coupling triggers the displacement of KIF5B from kinesin-1 complex increasing its binding to microtubule tracks and mitochondrial transport. High levels of Drp1 exacerbate this mechanism leading to the repositioning of mitochondria closer to nuclei. The reduction of Drp1 levels decreases kinesin-1 activation and induces the partial recovery of mitochondrial distribution. Drp1 overexpression is also associated with higher cyclin-dependent kinase-1 (Cdk-1) activation that promotes the persistent phosphorylation of desmin at Ser-31 and its disassembling. Fission inhibition has a positive effect on desmin Ser-31 phosphorylation, regardless of Cdk-1 activation, suggesting that induction of both fission and Cdk-1 are required for desmin collapse. This altered desmin architecture impairs mechanotransduction and compromises mitochondrial network stability priming mitochondria transport through microtubule-dependent trafficking with a mechanism that involves the Drp1-dependent regulation of kinesin-1 complex.


Assuntos
Desmina/metabolismo , Dinaminas/metabolismo , Cinesinas/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Animais , Proteína Quinase CDC2/metabolismo , Ativação Enzimática , Humanos , Camundongos Endogâmicos C57BL , Microtúbulos/metabolismo , Fosforilação , Fosfosserina/metabolismo , Transporte Proteico , Quinazolinonas/metabolismo , Succinato Desidrogenase/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA