Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 58
Filtrar
1.
Front Cell Dev Biol ; 12: 1368318, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38638530

RESUMO

A comprehensive understanding of the molecules that play key roles in the physiological and pathological homeostasis of the human intervertebral disc (IVD) remains challenging, as does the development of new therapeutic treatments. We recently found a positive correlation between IVD degeneration (IDD) and P2X7 receptor (P2X7R) expression increases both in the cytoplasm and in the nucleus. Using immunocytochemistry, reverse transcription PCR (RT-PCR), overexpression, and chromatin immunoprecipitation, we found that NFATc1 and hypoxia-inducible factor-1α (HIF-1α) are critical regulators of P2X7R. Both transcription factors are recruited at the promoter of the P2RX7 gene and involved in its positive and negative regulation, respectively. Furthermore, using the proximity ligation assay, we revealed that P2X7R and NFATc1 form a molecular complex and that P2X7R is closely associated with lamin A/C, a major component of the nuclear lamina. Collectively, our study identifies, for the first time, P2X7R and NFATc1 as markers of IVD degeneration and demonstrates that both NFATc1 and lamin A/C are interaction partners of P2X7R.

2.
Int J Mol Sci ; 24(7)2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-37047537

RESUMO

Fanconi anemia (FA) is a rare genetic disorder characterized by bone marrow failure and aplastic anemia. So far, 23 genes are involved in this pathology, and their mutations lead to a defect in DNA repair. In recent years, it has been observed that FA cells also display mitochondrial metabolism defects, causing an accumulation of intracellular lipids and oxidative damage. However, the molecular mechanisms involved in the metabolic alterations have not yet been elucidated. In this work, by using lymphoblasts and fibroblasts mutated for the FANC-A gene, oxidative phosphorylation (OxPhos) and mitochondria dynamics markers expression was analyzed. Results show that the metabolic defect does not depend on an altered expression of the proteins involved in OxPhos. However, FA cells are characterized by increased uncoupling protein UCP2 expression. FANC-A mutation is also associated with DRP1 overexpression that causes an imbalance in the mitochondrial dynamic toward fission and lower expression of Parkin and Beclin1. Treatment with P110, a specific inhibitor of DRP1, shows a partial mitochondrial function recovery and the decrement of DRP1 and UCP2 expression, suggesting a pivotal role of the mitochondrial dynamics in the etiopathology of Fanconi anemia.


Assuntos
Anemia de Fanconi , Dinâmica Mitocondrial , Humanos , Anemia de Fanconi/metabolismo , Proteína do Grupo de Complementação A da Anemia de Fanconi/genética , Proteína do Grupo de Complementação A da Anemia de Fanconi/metabolismo , Fibroblastos/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/genética , Proteínas/metabolismo , Dinaminas/metabolismo
3.
Front Cell Dev Biol ; 10: 1018102, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36467410

RESUMO

Lamin A is a main constituent of the nuclear lamina and contributes to nuclear shaping, mechano-signaling transduction and gene regulation, thus affecting major cellular processes such as cell cycle progression and entry into senescence, cellular differentiation and stress response. The role of lamin A in stress response is particularly intriguing, yet not fully elucidated, and involves prelamin A post-translational processing. Here, we propose prelamin A as the tool that allows lamin A plasticity during oxidative stress response and permits timely 53BP1 recruitment to DNA damage foci. We show that while PCNA ubiquitination, p21 decrease and H2AX phosphorylation occur soon after stress induction in the absence of prelamin A, accumulation of non-farnesylated prelamin A follows and triggers recruitment of 53BP1 to lamin A/C complexes. Then, the following prelamin A processing steps causing transient accumulation of farnesylated prelamin A and maturation to lamin A reduce lamin A affinity for 53BP1 and favor its release and localization to DNA damage sites. Consistent with these observations, accumulation of prelamin A forms in cells under basal conditions impairs histone H2AX phosphorylation, PCNA ubiquitination and p21 degradation, thus affecting the early stages of stress response. As a whole, our results are consistent with a physiological function of prelamin A modulation during stress response aimed at timely recruitment/release of 53BP1 and other molecules required for DNA damage repair. In this context, it becomes more obvious how farnesylated prelamin A accumulation to toxic levels alters timing of DNA damage signaling and 53BP1 recruitment, thus contributing to cellular senescence and accelerated organismal aging as observed in progeroid laminopathies.

4.
J Exp Clin Cancer Res ; 41(1): 273, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36096808

RESUMO

BACKGROUND: Lamins, key nuclear lamina components, have been proposed as candidate risk biomarkers in different types of cancer but their accuracy is still debated. AKTIP is a telomeric protein with the property of being enriched at the nuclear lamina. AKTIP has similarity with the tumor susceptibility gene TSG101. AKTIP deficiency generates genome instability and, in p53-/- mice, the reduction of the mouse counterpart of AKTIP induces the exacerbation of lymphomas. Here, we asked whether the distribution of AKTIP is altered in cancer cells and whether this is associated with alterations of lamins. METHODS: We performed super-resolution imaging, quantification of lamin expression and nuclear morphology on HeLa, MCF7, and A549 tumor cells, and on non-transformed fibroblasts from healthy donor and HGPS (LMNA c.1824C > T p.Gly608Gly) and EDMD2 (LMNA c.775 T > G) patients. As proof of principle model combining a defined lamin alteration with a tumor cell setting, we produced HeLa cells exogenously expressing the HGPS lamin mutant progerin that alters nuclear morphology. RESULTS: In HeLa cells, AKTIP locates at less than 0.5 µm from the nuclear rim and co-localizes with lamin A/C. As compared to HeLa, there is a reduced co-localization of AKTIP with lamin A/C in both MCF7 and A549. Additionally, MCF7 display lower amounts of AKTIP at the rim. The analyses in non-transformed fibroblasts show that AKTIP mislocalizes in HGPS cells but not in EDMD2. The integrated analysis of lamin expression, nuclear morphology, and AKTIP topology shows that positioning of AKTIP is influenced not only by lamin expression, but also by nuclear morphology. This conclusion is validated by progerin-expressing HeLa cells in which nuclei are morphologically altered and AKTIP is mislocalized. CONCLUSIONS: Our data show that the combined alteration of lamin and nuclear morphology influences the localization of the tumor-associated factor AKTIP. The results also point to the fact that lamin alterations per se are not predictive of AKTIP mislocalization, in both non-transformed and tumor cells. In more general terms, this study supports the thesis that a combined analytical approach should be preferred to predict lamin-associated changes in tumor cells. This paves the way of next translational evaluation to validate the use of this combined analytical approach as risk biomarker.


Assuntos
Lamina Tipo A , Progéria , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Fibroblastos/metabolismo , Células HeLa , Humanos , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Camundongos , Progéria/genética , Progéria/metabolismo , Progéria/patologia , Telômero/metabolismo
5.
Cell Death Dis ; 13(4): 346, 2022 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-35422060

RESUMO

Lamin A, a main constituent of the nuclear lamina, is involved in mechanosignaling and cell migration through dynamic interactions with the LINC complex, formed by the nuclear envelope proteins SUN1, SUN2 and the nesprins. Here, we investigated lamin A role in Ewing Sarcoma (EWS), an aggressive bone tumor affecting children and young adults. In patients affected by EWS, we found a significant inverse correlation between LMNA gene expression and tumor aggressiveness. Accordingly, in experimental in vitro models, low lamin A expression correlated with enhanced cell migration and invasiveness and, in vivo, with an increased metastatic load. At the molecular level, this condition was linked to altered expression and anchorage of nuclear envelope proteins and increased nuclear retention of YAP/TAZ, a mechanosignaling effector. Conversely, overexpression of lamin A rescued LINC complex organization, thus reducing YAP/TAZ nuclear recruitment and preventing cell invasiveness. These effects were also obtained through modulation of lamin A maturation by a statin-based pharmacological treatment that further elicited a more differentiated phenotype in EWS cells. These results demonstrate that drugs inducing nuclear envelope remodeling could be exploited to improve therapeutic strategies for EWS.


Assuntos
Membrana Nuclear , Sarcoma de Ewing , Humanos , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Membrana Nuclear/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo
6.
Aging Cell ; 20(1): e13285, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33393189

RESUMO

Hutchinson-Gilford progeria syndrome (HGPS) causes premature aging in children, with adipose tissue, skin and bone deterioration, and cardiovascular impairment. In HGPS cells and mouse models, high levels of interleukin-6, an inflammatory cytokine linked to aging processes, have been detected. Here, we show that inhibition of interleukin-6 activity by tocilizumab, a neutralizing antibody raised against interleukin-6 receptors, counteracts progeroid features in both HGPS fibroblasts and LmnaG609G/G609G progeroid mice. Tocilizumab treatment limits the accumulation of progerin, the toxic protein produced in HGPS cells, rescues nuclear envelope and chromatin abnormalities, and attenuates the hyperactivated DNA damage response. In vivo administration of tocilizumab reduces aortic lesions and adipose tissue dystrophy, delays the onset of lipodystrophy and kyphosis, avoids motor impairment, and preserves a good quality of life in progeroid mice. This work identifies tocilizumab as a valuable tool in HGPS therapy and, speculatively, in the treatment of a variety of aging-related disorders.


Assuntos
Interleucina-6/metabolismo , Progéria/genética , Envelhecimento , Animais , Humanos , Camundongos , Progéria/patologia
7.
Mol Cell Biochem ; 476(4): 1797-1811, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33452620

RESUMO

Transportin3 (TNPO3) shuttles the SR proteins from the cytoplasm to the nucleus. The SR family includes essential splicing factors, such as SRSF1, that influence alternative splicing, controlling protein diversity in muscle and satellite cell differentiation. Given the importance of alternative splicing in the myogenic process and in the maintenance of healthy muscle, alterations in the splicing mechanism might contribute to the development of muscle disorders. Combining confocal, structured illumination and electron microscopy, we investigated the expression of TNPO3 and SRSF1 during myogenesis, looking at nuclear and cytoplasmic compartments. We investigated TNPO3 and its interaction with SRSF1 and we observed that SRSF1 remained mainly localized in the nucleus, while TNPO3 decreased in the cytoplasm and was strongly clustered in the nuclei of differentiated myotubes. In conclusion, combining different imaging techniques led us to describe the behavior of TNPO3 and SRSF1 during myogenesis, showing that their dynamics follow the myogenic process and could influence the proteomic network necessary during myogenesis. The combination of different high-, super- and ultra-resolution imaging techniques led us to describe the behavior of TNPO3 and its interaction with SRSF1, looking at nuclear and cytoplasmic compartments. These observations represent a first step in understanding the role of TNPO3 and SRFSF1 in complex mechanisms, such as myogenesis.


Assuntos
Núcleo Celular , Citoplasma , Desenvolvimento Muscular , Fatores de Processamento de Serina-Arginina/metabolismo , beta Carioferinas/metabolismo , Animais , Linhagem Celular , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Citoplasma/metabolismo , Citoplasma/ultraestrutura , Camundongos , Microscopia Confocal , Microscopia Eletrônica
8.
Cancers (Basel) ; 13(2)2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33419058

RESUMO

Ankrd2 is a protein known for being mainly expressed in muscle fibers, where it participates in the mechanical stress response. Since both myocytes and osteoblasts are mesenchymal-derived cells, we were interested in examining the role of Ankrd2 in the progression of osteosarcoma which features a mechano-stress component. Although having been identified in many tumor-derived cell lines and -tissues, no study has yet described nor hypothesized any involvement for this protein in osteosarcoma tumorigenesis. In this paper, we report that Ankrd2 is expressed in cell lines obtained from human osteosarcoma and demonstrate a contribution by this protein in the pathogenesis of this insidious disease. Ankrd2 involvement in osteosarcoma development was evaluated in clones of Saos2, U2OS, HOS and MG63 cells stably expressing Ankrd2, through the investigation of hallmark processes of cancer cells. Interestingly, we found that exogenous expression of Ankrd2 influenced cellular growth, migration and clonogenicity in a cell line-dependent manner, whereas it was able to improve the formation of 3D spheroids in three out of four cellular models and enhanced matrix metalloproteinase (MMP) activity in all tested cell lines. Conversely, downregulation of Ankrd2 expression remarkably reduced proliferation and clonogenic potential of parental cells. As a whole, our data present Ankrd2 as a novel player in osteosarcoma development, opening up new therapeutic perspectives.

9.
Cells ; 9(7)2020 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-32698523

RESUMO

Lamin A/C has been implicated in the epigenetic regulation of muscle gene expression through dynamic interaction with chromatin domains and epigenetic enzymes. We previously showed that lamin A/C interacts with histone deacetylase 2 (HDAC2). In this study, we deepened the relevance and regulation of lamin A/C-HDAC2 interaction in human muscle cells. We present evidence that HDAC2 binding to lamina A/C is related to HDAC2 acetylation on lysine 75 and expression of p300-CBP associated factor (PCAF), an acetyltransferase known to acetylate HDAC2. Our findings show that lamin A and farnesylated prelamin A promote PCAF recruitment to the nuclear lamina and lamin A/C binding in human myoblasts committed to myogenic differentiation, while protein interaction is decreased in differentiating myotubes. Interestingly, PCAF translocation to the nuclear envelope, as well as lamin A/C-PCAF interaction, are reduced by transient expression of lamin A mutated forms causing Emery Dreifuss muscular dystrophy. Consistent with this observation, lamin A/C interaction with both PCAF and HDAC2 is significantly reduced in Emery-Dreifuss muscular dystrophy myoblasts. Overall, these results support the view that, by recruiting PCAF and HDAC2 in a molecular platform, lamin A/C might contribute to regulate their epigenetic activity required in the early phase of muscle differentiation.


Assuntos
Diferenciação Celular , Histona Desacetilase 2/metabolismo , Lamina Tipo A/metabolismo , Músculos/citologia , Fatores de Transcrição de p300-CBP/metabolismo , Animais , Células HEK293 , Humanos , Lamina Tipo A/genética , Camundongos , Modelos Biológicos , Distrofia Muscular de Emery-Dreifuss/genética , Distrofia Muscular de Emery-Dreifuss/patologia , Mutação/genética , Lâmina Nuclear/metabolismo , Fenótipo , Ligação Proteica
10.
Cells ; 9(6)2020 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-32517247

RESUMO

Reactive Oxygen Species (ROS) are reactive molecules required for the maintenance of physiological functions. Oxidative stress arises when ROS production exceeds the cellular ability to eliminate such molecules. In this study, we showed that oxidative stress induces post-translational modification of the inner nuclear membrane protein emerin. In particular, emerin is phosphorylated at the early stages of the oxidative stress response, while protein phosphorylation is abolished upon recovery from stress. A finely tuned balance between emerin phosphorylation and O-GlcNAcylation seems to govern this dynamic and modulates emerin-BAF interaction and BAF nucleoplasmic localization during the oxidative stress response. Interestingly, emerin post-translational modifications, similar to those observed during the stress response, are detected in cells bearing LMNA gene mutations and are characterized by a free radical generating environment. On the other hand, under oxidative stress conditions, a delay in DNA damage repair and cell cycle progression is found in cells from Emery-Dreifuss Muscular Dystrophy type 1, which do not express emerin. These results suggest a role of the emerin-BAF protein platform in the DNA damage response aimed at counteracting the detrimental effects of elevated levels of ROS.


Assuntos
Núcleo Celular/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Nucleares/metabolismo , Estresse Oxidativo , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Células HEK293 , Células HeLa , Humanos , Lamina Tipo A/deficiência , Lamina Tipo A/metabolismo , Peso Molecular , Distrofia Muscular de Emery-Dreifuss/patologia , Fosforilação , Ligação Proteica , Transporte Proteico , Espécies Reativas de Oxigênio/metabolismo
11.
Ageing Res Rev ; 62: 101073, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32446955

RESUMO

Lamin A, a main constituent of the nuclear lamina, is the major splicing product of the LMNA gene, which also encodes lamin C, lamin A delta 10 and lamin C2. Involvement of lamin A in the ageing process became clear after the discovery that a group of progeroid syndromes, currently referred to as progeroid laminopathies, are caused by mutations in LMNA gene. Progeroid laminopathies include Hutchinson-Gilford Progeria, Mandibuloacral Dysplasia, Atypical Progeria and atypical-Werner syndrome, disabling and life-threatening diseases with accelerated ageing, bone resorption, lipodystrophy, skin abnormalities and cardiovascular disorders. Defects in lamin A post-translational maturation occur in progeroid syndromes and accumulated prelamin A affects ageing-related processes, such as mTOR signaling, epigenetic modifications, stress response, inflammation, microRNA activation and mechanosignaling. In this review, we briefly describe the role of these pathways in physiological ageing and go in deep into lamin A-dependent mechanisms that accelerate the ageing process. Finally, we propose that lamin A acts as a sensor of cell intrinsic and environmental stress through transient prelamin A accumulation, which triggers stress response mechanisms. Exacerbation of lamin A sensor activity due to stably elevated prelamin A levels contributes to the onset of a permanent stress response condition, which triggers accelerated ageing.


Assuntos
Envelhecimento , Envelhecimento/genética , Humanos , Lamina Tipo A/genética , MicroRNAs , Mutação , Proteínas Nucleares , Progéria/genética , Precursores de Proteínas/genética
12.
Exp Gerontol ; 130: 110784, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31794853

RESUMO

The transgenic LmnaG609G progeric mouse represents an outstanding animal model for studying the human Hutchinson-Gilford Progeria Syndrome (HGPS) caused by a mutation in the LMNA gene, coding for the nuclear envelope protein Lamin A/C, and, as an important, more general scope, for studying the complex process governing physiological aging in humans. Here we give a comprehensive description of the peculiarities related to the breeding of LmnaG609G mice over a prolonged period of time, and of many features observed in a large colony for a 2-years period. We describe the breeding and housing conditions underlining the possible interference of the genetic background on the phenotype expression. This information represents a useful tool when planning and interpreting studies on the LmnaG609G mouse model, complementing any specific data already reported in the literature about this model since its production. It is also particularly relevant for the heterozygous mouse, which mirrors the genotype of the human pathology however requires an extended time to manifest symptoms and to be carefully studied.


Assuntos
Cruzamento , Heterozigoto , Homozigoto , Lamina Tipo A/genética , Progéria/genética , Animais , Modelos Animais de Doenças , Proteínas de Membrana/genética , Camundongos , Mutação , Fenótipo
13.
Oxid Med Cell Longev ; 2019: 7318796, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31428229

RESUMO

Ankrd2 (ankyrin repeats containing domain 2) or Arpp (ankyrin repeat, PEST sequence, and proline-rich region) is a member of the muscle ankyrin repeat protein family. Ankrd2 is mostly expressed in skeletal muscle, where it plays an intriguing role in the transcriptional response to stress induced by mechanical stimulation as well as by cellular reactive oxygen species. Our studies in myoblasts from Emery-Dreifuss muscular dystrophy 2, a LMNA-linked disease affecting skeletal and cardiac muscles, demonstrated that Ankrd2 is a lamin A-binding protein and that mutated lamins found in Emery-Dreifuss muscular dystrophy change the dynamics of Ankrd2 nuclear import, thus affecting oxidative stress response. In this review, besides describing the latest advances related to Ankrd2 studies, including novel discoveries on Ankrd2 isoform-specific functions, we report the main findings on the relationship of Ankrd2 with A-type lamins and discuss known and potential mechanisms involving defective Ankrd2-lamin A interplay in the pathogenesis of muscular laminopathies.


Assuntos
Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Distrofia Muscular de Emery-Dreifuss/patologia , Proteínas Nucleares/metabolismo , Estresse Oxidativo , Proteínas Repressoras/metabolismo , Humanos , Lamina Tipo A/metabolismo , Mecanotransdução Celular , Proteínas Musculares/química , Distrofia Muscular de Emery-Dreifuss/metabolismo , Miocárdio/metabolismo , Proteínas Nucleares/química , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas Repressoras/química
14.
Exp Mol Med ; 51(8): 1-17, 2019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375660

RESUMO

Type-2 Familial Partial Lipodystrophy is caused by LMNA mutations. Patients gradually lose subcutaneous fat from the limbs, while they accumulate adipose tissue in the face and neck. Several studies have demonstrated that autophagy is involved in the regulation of adipocyte differentiation and the maintenance of the balance between white and brown adipose tissue. We identified deregulation of autophagy in laminopathic preadipocytes before induction of differentiation. Moreover, in differentiating white adipocyte precursors, we observed impairment of large lipid droplet formation, altered regulation of adipose tissue genes, and expression of the brown adipose tissue marker UCP1. Conversely, in lipodystrophic brown adipocyte precursors induced to differentiate, we noticed activation of autophagy, formation of enlarged lipid droplets typical of white adipocytes, and dysregulation of brown adipose tissue genes. In agreement with these in vitro results indicating conversion of FPLD2 brown preadipocytes toward the white lineage, adipose tissue from FPLD2 patient neck, an area of brown adipogenesis, showed a white phenotype reminiscent of its brown origin. Moreover, in vivo morpho-functional evaluation of fat depots in the neck area of three FPLD2 patients by PET/CT analysis with cold stimulation showed the absence of brown adipose tissue activity. These findings highlight a new pathogenetic mechanism leading to improper fat distribution in lamin A-linked lipodystrophies and show that both impaired white adipocyte turnover and failure of adipose tissue browning contribute to disease.


Assuntos
Adipócitos Marrons/fisiologia , Adipócitos/patologia , Autofagia/fisiologia , Diferenciação Celular , Transdiferenciação Celular , Lipodistrofia Parcial Familiar/patologia , Adipócitos/fisiologia , Adipogenia/fisiologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/fisiologia , Adulto , Transdiferenciação Celular/fisiologia , Células Cultivadas , Feminino , Humanos , Lipodistrofia Parcial Familiar/metabolismo , Lipodistrofia Parcial Familiar/fisiopatologia , Pessoa de Meia-Idade , Adulto Jovem
15.
Front Cell Dev Biol ; 7: 6, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30766871

RESUMO

We recently identified lamin A/C as a docking molecule for human histone deacetylase 2 (HDAC2) and showed involvement of HDAC2-lamin A/C complexes in the DNA damage response. We further showed that lamin A/C-HDAC2 interaction is altered in Hutchinson-Gilford Progeria syndrome and other progeroid laminopathies. Here, we show that both inhibitors of lamin A maturation and small molecules inhibiting HDAC activity affect lamin A/C interaction with HDAC2. While statins, which inhibit prelamin A processing, reduce protein interaction, HDAC inhibitors strengthen protein binding. Moreover, treatment with HDAC inhibitors restored the enfeebled lamin A/C-HDAC2 interaction observed in HGPS cells. Based on these results, we propose that prelamin A levels as well as HDAC2 activation status might influence the extent of HDAC2 recruitment to the lamin A/C-containing platform and contribute to modulate HDAC2 activity. Our study links prelamin A processing to HDAC2 regulation and provides new insights into the effect of statins and histone deacetylase inhibitors on lamin A/C functionality in normal and progeroid cells.

16.
Cell Physiol Biochem ; 42(1): 169-184, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28531892

RESUMO

BACKGROUND: Ankrd2 is a stress responsive protein mainly expressed in muscle cells. Upon the application of oxidative stress, Ankrd2 translocates into the nucleus where it regulates the activity of genes involved in cellular response to stress. Emery-Dreifuss Muscular Dystrophy 2 (EDMD2) is a muscular disorder caused by mutations of the gene encoding lamin A, LMNA. As well as many phenotypic abnormalities, EDMD2 muscle cells also feature a permanent basal stress state, the underlying molecular mechanisms of which are currently unclear. METHODS: Experiments were performed in EDMD2-lamin A overexpressing cell lines and EDMD2-affected human myotubes. Oxidative stress was produced by H2O2 treatment. Co-immunoprecipitation, cellular subfractionation and immunofluorescence analysis were used to validate the relation between Ankrd2 and forms of lamin A; cellular sensibility to stress was monitored by the analysis of Reactive Oxygen Species (ROS) release and cell viability. RESULTS: Our data demonstrate that oxidative stress induces the formation of a complex between Ankrd2 and lamin A. However, EDMD2-lamin A mutants were able to bind and mislocalize Ankrd2 in the nucleus even under basal conditions. Nonetheless, cells co-expressing Ankrd2 and EDMD2-lamin A mutants were more sensitive to oxidative stress than the Ankrd2-wild type lamin A counterpart. CONCLUSIONS: For the first time, we present evidence that in muscle fibers from patients affected by EDMD2, Ankrd2 has an unusual nuclear localization. By introducing a plausible mechanism ruling this accumulation, our data hint at a novel function of Ankrd2 in the pathogenesis of EDMD2-affected cells.


Assuntos
Núcleo Celular/metabolismo , Lamina Tipo A/metabolismo , Proteínas Musculares/metabolismo , Distrofia Muscular de Emery-Dreifuss/patologia , Proteínas Nucleares/metabolismo , Estresse Oxidativo , Proteínas Repressoras/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Células HEK293 , Humanos , Peróxido de Hidrogênio/toxicidade , Imunoprecipitação , Lamina Tipo A/química , Lamina Tipo A/genética , Microscopia de Fluorescência , Proteínas Musculares/química , Proteínas Musculares/genética , Músculo Esquelético/citologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Distrofia Muscular de Emery-Dreifuss/genética , Distrofia Muscular de Emery-Dreifuss/metabolismo , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Estresse Oxidativo/efeitos dos fármacos , Plasmídeos/genética , Plasmídeos/metabolismo , Ligação Proteica , Prenilação de Proteína/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/genética
17.
Springerplus ; 5(1): 1427, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27625981

RESUMO

BACKGROUND: Human mesenchymal stem cells (MSC), during in vitro expansion, undergo a progressive loss of proliferative potential that leads to the senescent state, associated with a reduction of their "medicinal" properties. This may hampers their efficacy in the treatment of injured tissues. Quality controls on MSC-based cell therapy products should include an assessment of the senescent state. However, a reliable and specific marker is still missing. From studies on lamin-associated disorders, has emerged the correlation between defective lamin A maturation and cellular senescence. FINDINGS: Primary cultured hMSC lines (n = 3), were analyzed by immunostaining at different life-span stages for the accumulation of prelamin A, along with other markers of cellular senescence. During culture, cells at the last stage of their life span displayed evident signs of senescence consistent with the positivity of SA-ß-gal staining. We also observed a significant increase of prelamin A positive cells. Furthermore, we verified that the cells marked by prelamin A were also positive for p21(Waf1) while negative for Ki67. CONCLUSIONS: Overall data support that the detection of prelamin A identifies senescent MSC, providing an easy and reliable tool to be use alone or in combination with known senescence markers to screen MSC before their use in clinical applications.

18.
Oncotarget ; 7(13): 15662-77, 2016 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-26701887

RESUMO

Chromatin disorganization is one of the major alterations linked to prelamin A processing impairment. In this study we demonstrate that BAF is necessary to modulate prelamin A effects on chromatin structure. We show that when prelamin A and BAF cannot properly interact no prelamin A-dependent effects on chromatin occur; similar to what is observed in human Nestor Guillermo Progeria Syndrome cells harboring a BAF mutation, in HEK293 cells expressing a BAF mutant unable to bind prelamin A, or in siRNA mediated BAF-depleted HEK293 cells expressing prelamin A. BAF is necessary to induce histone trimethyl-H3K9 as well as HP1-alpha and LAP2-alpha nuclear relocalization in response to prelamin A accumulation. These findings are enforced by electron microscopy evaluations showing how the prelamin A-BAF interaction governs overall chromatin organization. Finally, we demonstrate that the LAP2-alpha nuclear localization defect observed in HGPS cells involves the progerin-BAF interaction, thus establishing a functional link between BAF and prelamin A pathological forms.


Assuntos
Cromatina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Lamina Tipo A/metabolismo , Proteínas Nucleares/metabolismo , Proteínas de Ligação a DNA/genética , Células HEK293 , Humanos , Mutação , Proteínas Nucleares/genética , Progéria/genética , Progéria/metabolismo , Progéria/patologia
19.
Oncotarget ; 6(30): 29914-28, 2015 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-26359359

RESUMO

Hutchinson Gilford progeria syndrome is a fatal disorder characterized by accelerated aging, bone resorption and atherosclerosis, caused by a LMNA mutation which produces progerin, a mutant lamin A precursor. Progeria cells display progerin and prelamin A nuclear accumulation, altered histone methylation pattern, heterochromatin loss, increased DNA damage and cell cycle alterations. Since the LMNA promoter contains a retinoic acid responsive element, we investigated if all-trans retinoic acid administration could lower progerin levels in cultured fibroblasts. We also evaluated the effect of associating rapamycin, which induces autophagic degradation of progerin and prelamin A. We demonstrate that all-trans retinoic acid acts synergistically with low-dosage rapamycin reducing progerin and prelamin A, via transcriptional downregulation associated with protein degradation, and increasing the lamin A to progerin ratio. These effects rescue cell dynamics and cellular proliferation through recovery of DNA damage response factor PARP1 and chromatin-associated nuclear envelope proteins LAP2α and BAF. The combined all-trans retinoic acid-rapamycin treatment is dramatically efficient, highly reproducible, represents a promising new approach in Hutchinson-Gilford Progeria therapy and deserves investigation in ageing-associated disorders.


Assuntos
Fibroblastos/efeitos dos fármacos , Lamina Tipo A/metabolismo , Sirolimo/farmacologia , Tretinoína/farmacologia , Antineoplásicos/farmacologia , Western Blotting , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Proteínas de Ligação a DNA/metabolismo , Sinergismo Farmacológico , Fibroblastos/metabolismo , Fibroblastos/ultraestrutura , Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Humanos , Lamina Tipo A/genética , Lisina/metabolismo , Proteínas de Membrana/metabolismo , Metilação/efeitos dos fármacos , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Proteínas Nucleares/metabolismo , Fenótipo , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , Progéria/genética , Progéria/metabolismo , Progéria/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
20.
J Cell Physiol ; 230(3): 603-9, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25161103

RESUMO

Bone marrow (BM) failure, increased risk of myelodysplastic syndrome, acute leukaemia and solid tumors, endocrinopathies and congenital abnormalities are the major clinical problems in Fanconi anemia patients (FA). Chromosome instability and DNA repair defects are the cellular characteristics used for the clinical diagnosis. However, these biological defects are not sufficient to explain all the clinical phenotype of FA patients. The known defects are structural alteration in cell cytoskeleton, altered structural organization for intermediate filaments, nuclear lamina, and mitochondria. These are associated with different expression and/or maturation of the structural proteins vimentin, mitofilin, and lamin A/C suggesting the involvement of metalloproteinases (MPs). Matrix metalloproteinases (MMP) are involved in normal physiological processes such as human skeletal tissue development, maturation, and hematopoietic reconstitution after bone marrow suppression. Current observations upon the eventual role of MPs in FA cells are largely inconclusive. We evaluated the overall MPs activity in FA complementation group A (FANCA) cells by exposing them to the antioxidants N-acetyl cysteine (NAC) and resveratrol (RV). This work supports the hypothesis that treatment of Fanconi patients with antioxidants may be important in FA therapy.


Assuntos
Anemia de Fanconi/metabolismo , Metaloproteases/metabolismo , Músculo Esquelético/crescimento & desenvolvimento , Oxigênio/metabolismo , Antioxidantes/administração & dosagem , Medula Óssea/metabolismo , Medula Óssea/patologia , Instabilidade Cromossômica/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA , Anemia de Fanconi/tratamento farmacológico , Anemia de Fanconi/patologia , Feminino , Humanos , Metaloproteases/antagonistas & inibidores , Proteínas Mitocondriais/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Vimentina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA