Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.446
Filtrar
1.
J Chem Inf Model ; 63(2): 605-618, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36607244

RESUMO

Leukocyte adhesion deficiency-1 (LAD-1) disorder is a severe immunodeficiency syndrome caused by deficiency or mutation of ß2 integrin. The phosphorylation on threonine 758 of ß2 integrin acts as a molecular switch inhibiting the binding of filamin. However, the switch mechanism of site-specific phosphorylation at the atom level is still poorly understood. To resolve the regulation mechanism, all-atom molecular dynamics simulation and Markov state model were used to study the dynamic regulation pathway of phosphorylation. Wild type system possessed lower binding free energy and fewer number of states than the phosphorylated system. Both systems underwent local disorder-to-order conformation conversion when achieving steady states. To reach steady states, wild type adopted less number of transition paths/shortest path according to the transition path theory than the phosphorylated system. The underlying phosphorylated regulation pathway was from P1 to P0 and then P4 state, and the main driving force should be hydrogen bond and hydrophobic interaction disturbing the secondary structure of phosphorylated states. These studies will shed light on the pathogenesis of LAD-1 disease and lay a foundation for drug development.


Assuntos
Antígenos CD18 , Simulação de Dinâmica Molecular , Antígenos CD18/química , Antígenos CD18/genética , Antígenos CD18/metabolismo , Filaminas/química , Filaminas/metabolismo , Fosforilação
2.
Nat Commun ; 14(1): 34, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36596803

RESUMO

The γ-aminobutyric acid type B (GABAB) receptor is a prototypical family C G protein-coupled receptor (GPCR) that plays a key role in the regulation of synaptic transmission. Although growing evidence suggests that GPCR signaling in neurons might be highly organized in time and space, limited information is available about the mechanisms controlling the nanoscale organization of GABAB receptors and other GPCRs on the neuronal plasma membrane. Using a combination of biochemical assays in vitro, single-particle tracking, and super-resolution microscopy, we provide evidence that the spatial organization and diffusion of GABAB receptors on the plasma membrane are governed by dynamic interactions with filamin A, which tethers the receptors to sub-cortical actin filaments. We further show that GABAB receptors are located together with filamin A in small nanodomains in hippocampal neurons. These interactions are mediated by the first intracellular loop of the GABAB1 subunit and modulate the kinetics of Gαi protein activation in response to GABA stimulation.


Assuntos
Receptores de GABA-B , Receptores de GABA , Receptores de GABA/metabolismo , Filaminas , Receptores de GABA-B/metabolismo , Membrana Celular/metabolismo , Ácido gama-Aminobutírico/metabolismo
3.
Int J Mol Med ; 51(3)2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36704846

RESUMO

Filamin A (FLNA) is a high molecular weight cytoskeleton protein important for cell locomotion. A relationship between FLNA mutations and pulmonary arterial hypertension (PAH) has previously been reported; however, the detailed mechanism remains unclear. The present study aimed to explore the role of FLNA in vascular smooth muscle cells during the development of PAH. Smooth muscle cell (SMC)­specific FLNA­deficient mice were generated and the mice were then exposed to hypoxia for 28 days to build the mouse model of PAH. Human pulmonary arterial smooth muscle cells (PASMCs) were also cultured and transfected with FLNA small interfering RNA or overexpression plasmids to investigate the effects of FLNA on PASMC proliferation and migration. Notably, compared with control individuals, the expression levels of FLNA were increased in lung tissues from patients with PAH, and it was obviously expressed in the PASMCs of pulmonary arterioles. FLNA deficiency in SMCs attenuated hypoxia­induced pulmonary hypertension and pulmonary vascular remodeling. In vitro studies suggested that absence of FLNA impaired PASMC proliferation and migration, and produced lower levels of phosphorylated (p)­PAK­1 and RAC1 activity. However, FLNA overexpression promoted PASMC proliferation and migration, and increased the expression levels of p­PAK­1 and RAC1 activity. The present study highlights the role of FLNA in pulmonary vascular remodeling; therefore, it could serve as a potential target for the treatment of PAH.


Assuntos
Filaminas , Hipertensão Pulmonar , Hipertensão Arterial Pulmonar , Animais , Humanos , Camundongos , Proliferação de Células , Células Cultivadas , Filaminas/genética , Filaminas/metabolismo , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/metabolismo , Hipóxia/complicações , Hipóxia/genética , Hipóxia/metabolismo , Miócitos de Músculo Liso/metabolismo , Hipertensão Arterial Pulmonar/genética , Hipertensão Arterial Pulmonar/metabolismo , Artéria Pulmonar/metabolismo , Transdução de Sinais , Remodelação Vascular/genética
4.
J Genet ; 1012022.
Artigo em Inglês | MEDLINE | ID: mdl-36560844

RESUMO

Pediatric restrictive cardiomyopathy (RCM) is the rarest in its group and accounts for only 2.5-5% of all the diagnosed cardiomyopathies in children. It is a relentless disease with poor prognosis, and heart transplantation is the only long-term treatment option. The aetiology of pediatric RCM varies and includes conditions such as endomyocardial fibrosis, storage disorder (Fabry's disease, MPS), drugs, radiation, post-cardiac transplantation and genetic. Genetic causes encompasses mutations in sarcomeric (troponin I and T, actin, myosin and titin) and nonsarcomeric protein-coding genes (Desmin, RSK2, lamin A/C and bcl-2-associated athanogene 3 (BAG3)). Inheritance of RCM could be autosomal dominant, autosomal recessive and X-linked. Here, we report a case of RCM in an adolescent girl, who was symptomatic with palpitations and breathlessness on exertion. The patient showed presence of rare variants in FLNC (c.5707G>A; p.Glu1903Lys) and BAG3 genes (c.610G>A; p.Gly204Arg). These two variants were detected individually in asymptomatic father and mother, respectively. FLNC gene codes for gamma filamin. These filamin proteins play important role in maintaining the structural integrity of the sarcomere. BAG3 is the main component of the chaperone-assisted selective autophagy (CASA) pathway. Mutant FLNC leads to the formation of protein aggregates which are cleared by an active protein quality control system including CASA pathway. For further verification, in silico protein-protein interaction was performed using online software and tools. The results showed evident interaction between FLNC and BAG3 with significant binding score (-826.6) between them.


Assuntos
Cardiomiopatias , Cardiomiopatia Restritiva , Humanos , Cardiomiopatia Restritiva/genética , Filaminas/genética , Filaminas/química , Filaminas/metabolismo , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Mutação , Fenótipo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Reguladoras de Apoptose/genética
5.
Genes (Basel) ; 13(12)2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36553581

RESUMO

Filamin protein is characterized by an N-terminal actin-binding domain that is followed by 24 Ig (immunoglobulin)-like repeats, which act as hubs for interactions with a variety of proteins. In humans, this family has been found to be involved in cancer cell invasion and metastasis and can be involved in a variety of growth signal transduction processes, but it is less studied in plants. Therefore, in this study, 54 Filamin gene family members from 23 plant species were investigated and divided into two subfamilies: FLMN and GEX2. Subcellular localization showed that most of the Filamin gene family members were located in the cell membrane. A total of 47 Filamin gene pairs were identified, most of which were whole-genome copies. Through the analyses of cis-acting elements, expression patterns and quantitative fluorescence, it was found that GH_ A02G0519 and GH_ D02G0539 are mainly expressed in the reproductive organs of upland cotton, and their interacting proteins are also related to the fertilization process, whereas GH_A02G0216 and GH_D02G0235 were related to stress. Thus, it is speculated that two genes of the GEX2 subfamily (GH_A02G0519 and GH_D02G0539) may be involved in the reproductive development of cotton and may affect the fertilization process of cotton. This study provides a theoretical basis for the further study of the cotton Filamin gene family.


Assuntos
Genoma de Planta , Gossypium , Filaminas/genética , Filaminas/metabolismo , Perfilação da Expressão Gênica , Gossypium/genética , Filogenia
6.
Int Heart J ; 63(6): 1201-1204, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36372407

RESUMO

Sinus of Valsalva aneurysm (SVA) is a rare cardiovascular disease with male predominance. Recently, an association with aortic aneurysm and SVA has been revealed in periventricular nodular heterotopia patients with loss-of-function Filamin A (FLNA) mutations, which were located on chromosome X and almost exclusively affect females.Among patients hospitalized for aortic surgery with aortic root diameter over 4.0 cm, next-generation sequencing was performed to investigate 30 candidate genes related to inherited aortic aneurysm syndromes and familial thoracic aortic aneurysm and dissection. The present report reviewed an electronic case database and identified two female cases of unruptured SVA with heterozygous FLNA truncating mutations.Case 1 displaying a rare SVA phenotype involving left and noncoronary sinus harbored a nonsense variant p.Tyr1720Ter/c.5160C > G. Case 2 displayed right and noncoronary SVA with predominantly enlarged right coronary sinus, posterior mitral valve prolapse, and harbored a frameshift variant p.Val1724fs*68/c.5171_5172delTG. Both novel mutations resulted in the premature termination of filamin A with the loss of functional Rod 2 and dimerization region.The present report raised the possibility of the presence of a cardiovascular onset form in the spectrum of FLNA hereditary diseases. The association between SVA and loss-of-function FLNA mutations indicates a unique etiology and pathogenesis among female patients, which requires further investigation to establish the linkage between FLNA variants and a wide spectrum of phenotypes.


Assuntos
Aneurisma da Aorta Torácica , Aneurisma Aórtico , Seio Aórtico , Masculino , Feminino , Humanos , Filaminas/genética , Aneurisma Aórtico/complicações , Fenótipo , Aneurisma da Aorta Torácica/diagnóstico , Aneurisma da Aorta Torácica/genética , Aneurisma da Aorta Torácica/complicações
7.
Biochem J ; 479(22): 2351-2364, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36239738

RESUMO

Apoptosis is a critical process for the maintenance of cell populations, and involves mitochondrial depolarization, the sequential cleavage of caspase-9 and -3, followed by the externalization of phosphatidylserine (PS) on the plasma membrane. The actin cytoskeleton and its accessory proteins are known regulators of apoptotic signaling in nucleated cells but their roles in platelet apoptosis are undefined. Filamin A (FLNA) is a ubiquitously expressed actin-crosslinking protein that also serves as an intracellular signaling scaffold. Here we used platelets from mice with a platelet-specific FLNA deficiency (Flnafl/Y, Pf4-cre/+, termed platelet-specific knockout) to test the role of FLNA in platelet apoptosis. Treatment with the BH3-mimetic drug ABT-737 induced caspase-3 cleavage and PS exposure in platelets from floxed mice (Flnafl/Y, termed control) but these effects were essentially abrogated in FLNA-null platelets (platelet-specific knockout). Protein kinase C (PKC), a known FLNA ligand, was also activated by ABT-737, and PKC's phosphorylation of its downstream substrates was attenuated in FLNA-null platelets. The PKC inhibitor bisindolylmaleimide (BIM) also reduced caspase-3 cleavage, thus essentially phenocopying the FLNA-null platelets. Notably, the caspase-3 cleavage defect in FLNA-null platelets was rescued by the PKC-activating phorbol ester PMA, suggesting that FLNA and PKC share a common pathway in regulating platelet apoptosis. Mitochondrial depolarization and caspase-9 cleavage were unaffected by BIM treatment, suggesting that PKC specifically controls the downstream caspase-3 point of the pro-apoptotic signaling pathway. These data point to a novel role for FLNA in the regulation of platelet apoptosis, thus providing an improved understanding of how circulating platelet counts are maintained.


Assuntos
Plaquetas , Filaminas , Proteína Quinase C , Animais , Camundongos , Apoptose , Plaquetas/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Caspase 9/genética , Caspase 9/metabolismo , Filaminas/genética , Filaminas/metabolismo , Fosfatidilserinas/metabolismo , Proteína Quinase C/metabolismo
8.
Stem Cell Res ; 64: 102928, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36194907

RESUMO

Dilated cardiomyopathy (DCM) is a heterogeneous cardiac disorder characterized by left ventricular dilatation and dysfunction. Mutations in dozens of cardiac genes have been connected to the development of DCM including the filamin C gene (FLNC). We generated two induced pluripotent stem cell (iPSCs) lines from DCM patients carrying single missense heterozygote FLNC mutations (c.6689G > A and c.3745G > A). Both lines expressed high levels of pluripotency markers, differentiated into derivatives of the three germ layers and possessed normal karyotypes. The derived iPSC lines can serve as powerful tools to model DCM in vitro and as a platform for therapeutic development.


Assuntos
Cardiomiopatia Dilatada , Células-Tronco Pluripotentes Induzidas , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Cardiomiopatia Dilatada/genética , Heterozigoto , Filaminas/genética , Filaminas/metabolismo , Mutação/genética
9.
Biol Open ; 11(9)2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-36066120

RESUMO

Filamins are large proteins with actin-binding properties. Mutations in FLNC, one of the three filamin genes in humans, have recently been implicated in dominant cardiomyopathies, but the underlying mechanisms are not well understood. Here, we aimed to use Drosophila melanogaster as a new in vivo model to study these diseases. First, we show that adult-specific cardiac RNAi-induced depletion of Drosophila Filamin (dFil) induced cardiac dilatation, impaired systolic function and sarcomeric alterations, highlighting its requirement for cardiac function and maintenance of sarcomere integrity in the adult stage. Next, we introduced in the cheerio gene, using CRISPR/Cas9 gene editing, three missense variants, previously identified in patients with hypertrophic cardiomyopathy. Flies carrying these variants did not exhibit cardiac defects or increased propensity to form filamin aggregates, arguing against their pathogenicity. Finally, we show that deletions of the C-term part of dFil carrying the last four Ig-like domains are dispensable for cardiac function. Collectively, these results highlight the relevance of this model to explore the cardiac function of filamins and increase our understanding of physio-pathological mechanisms involved in FLNC-related cardiomyopathies. This article has an associated First Person interview with the first author of the paper.


Assuntos
Cardiomiopatias , Drosophila , Actinas/metabolismo , Animais , Sistemas CRISPR-Cas , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Drosophila/metabolismo , Proteínas de Drosophila , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Filaminas/química , Filaminas/genética , Filaminas/metabolismo , Humanos , Virulência
10.
Biochemistry (Mosc) ; 87(8): 800-811, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36171660

RESUMO

Small heat shock proteins (sHsps) play an important role in the maintenance of proteome stability and, particularly, in stabilization of the cytoskeleton and cell contractile apparatus. Cell exposure to different types of stress is accompanied by the translocation of sHsps onto actin filaments; therefore, it is commonly believed that the sHsps are true actin-binding proteins. Investigations of last years have shown that this assumption is incorrect. Stress-induced translocation of sHsp to actin filaments is not the result of direct interaction of these proteins with intact actin, but results from the chaperone-like activity of sHsps and their interaction with various actin-binding proteins. HspB1 and HspB5 interact with giant elastic proteins titin and filamin thus providing an integrity of the contractile apparatus and its proper localization in the cell. HspB6 binds to the universal adapter protein 14-3-3 and only indirectly affects the structure of actin filament. HspB7 interacts with filamin C and controls actin filament assembly. HspB8 forms tight complex with the universal regulatory and adapter protein Bag3 and participates in the chaperone-assisted selective autophagy (CASA) of actin-binding proteins (e.g., filamin), as well as in the actin-depending processes taking place in mitoses. Hence, the mechanisms of sHsp participation in the maintenance of the contractile apparatus and cytoskeleton are much more complicated and diverse than it has been postulated earlier and are not limited to direct interactions of sHsps with actin. The old hypothesis on the direct binding of sHsps to intact actin should be revised and further detailed investigation on the sHsp interaction with minor proteins participating in the formation and remodeling of actin filaments is required.


Assuntos
Proteínas de Choque Térmico Pequenas , Proteínas 14-3-3/metabolismo , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Conectina , Filaminas/metabolismo , Proteínas de Choque Térmico HSP27/metabolismo , Proteínas de Choque Térmico Pequenas/química , Proteoma/metabolismo
11.
Circ Res ; 131(9): 748-764, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36164986

RESUMO

BACKGROUND: Atherosclerosis occurs mainly at arterial branching points exposed to disturbed blood flow. How MST1 (mammalian sterile 20-like kinase 1), the primary kinase in the mechanosensitive Hippo pathway modulates disturbed flow induced endothelial cells (ECs) activation and atherosclerosis remains unclear. METHODS: To assess the role of MST1 in vivo, mice with EC-specific Mst1 deficiency on ApoE-/- background (Mst1iECKOApoE-/-) were used in an atherosclerosis model generated by carotid artery ligation. Mass spectrometry, immunoprecipitation, proximity ligation assay, and dye uptake assay were used to identify the functional substrate of MST1. Human umbilical vein endothelial cells and human aortic endothelial cells were subjected to oscillatory shear stress that mimic disturbed flow in experiments conducted in vitro. RESULTS: We found that the phosphorylation of endothelial MST1 was significantly inhibited in oscillatory shear stress-exposed regions of human and mouse arteries and ECs. Ectopic lenti-mediated overexpression of wild-type MST1, but not a kinase-deficient mutant of MST1, reversed disturbed flow-caused EC activation and atherosclerosis in EC-specific Mst1 deficiency on ApoE-/- background (Mst1iECKOApoE-/-). Inhibition of MST1 by oscillatory shear stress led to reduced phosphorylation of Cx43 (connexin 43) at Ser255, the Cx43 hemichannel open, EC activation, and atherosclerosis, which were blocked by TAT-GAP19, a Cx43 hemichannel inhibitory peptide. Mass spectrometry studies identified that Filamin B fueled the translocation of Cx43 to lipid rafts for further hemichannel open. Finally, lenti-mediated overexpression of the Cx43S255 mutant into glutamate to mimic phosphorylation blunted disturbed flow-induced EC activation, thereby inhibiting the atherogenesis in both ApoE-/- and Mst1 iECKOApoE-/- mice. CONCLUSIONS: Our study reveals that inhibition of the MST1-Cx43 axis is an essential driver of oscillatory shear stress-induced endothelial dysfunction and atherosclerosis, which provides a new therapeutic target for the treatment of atherosclerosis.


Assuntos
Aterosclerose , Conexina 43 , Animais , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Aterosclerose/metabolismo , Células Cultivadas , Conexina 43/metabolismo , Filaminas/metabolismo , Glutamatos/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Mamíferos , Camundongos , Estresse Mecânico
12.
Orphanet J Rare Dis ; 17(1): 358, 2022 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104822

RESUMO

BACKGROUND: FLNC is one of the few genes associated with all types of cardiomyopathies, but it also underlies neuromuscular phenotype. The combination of concomitant neuromuscular and cardiac involvement is not often observed in filaminopathies and the impact of this on the disease prognosis has hitherto not been analyzed. RESULTS: Here we provide a detailed clinical, genetic, and structural prediction analysis of distinct FLNC-associated phenotypes based on twelve pediatric cases. They include early-onset restrictive cardiomyopathy (RCM) in association with congenital myopathy. In all patients the initial diagnosis was established during the first year of life and in five out of twelve (41.7%) patients the first symptoms were observed at birth. RCM was present in all patients, often in combination with septal defects. No ventricular arrhythmias were noted in any of the patients presented here. Myopathy was confirmed by neurological examination, electromyography, and morphological studies. Arthrogryposes was diagnosed in six patients and remained clinically meaningful with increasing age in three of them. One patient underwent successful heart transplantation at the age of 18 years and two patients are currently included in the waiting list for heart transplantation. Two died due to congestive heart failure. One patient had ICD instally as primary prevention of SCD. In ten out of twelve patients the disease was associated with missense variants and only in two cases loss of function variants were detected. In half of the described cases, an amino acid substitution A1186V, altering the structure of IgFLNc10, was found. CONCLUSIONS: The present description of twelve cases of early-onset restrictive cardiomyopathy with congenital myopathy and FLNC mutation, underlines a distinct unique phenotype that can be suggested as a separate clinical form of filaminopathies. Amino acid substitution A1186V, which was observed in half of the cases, defines a mutational hotspot for the reported combination of myopathy and cardiomyopathy. Several independent molecular mechanisms of FLNC mutations linked to filamin structure and function can explain the broad spectrum of FLNC-associated phenotypes. Early disease presentation and unfavorable prognosis of heart failure demanding heart transplantation make awareness of this clinical form of filaminopathy of great clinical importance.


Assuntos
Cardiomiopatias , Cardiomiopatia Restritiva , Doenças Musculares , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Cardiomiopatia Restritiva/genética , Filaminas/química , Filaminas/genética , Filaminas/metabolismo , Humanos , Fenótipo
13.
Front Endocrinol (Lausanne) ; 13: 892668, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35992099

RESUMO

The process of GPCR dimerization can have profound effects on GPCR activation, signaling, and intracellular trafficking. Somatostatin receptors (SSTs) are class A GPCRs abundantly expressed in pituitary tumors where they represent the main pharmacological targets of somatostatin analogs (SSAs), thanks to their antisecretory and antiproliferative actions. The cytoskeletal protein filamin A (FLNA) directly interacts with both somatostatin receptor type 2 (SST2) and 5 (SST5) and regulates their expression and signaling in pituitary tumoral cells. So far, the existence and physiological relevance of SSTs homo- and hetero-dimerization in the pituitary have not been explored. Moreover, whether octreotide or pasireotide may play modulatory effects and whether FLNA may participate to this level of receptor organization have remained elusive. Here, we used a proximity ligation assay (PLA)-based approach for the in situ visualization and quantification of SST2/SST5 dimerization in rat GH3 as well as in human melanoma cells either expressing (A7) or lacking (M2) FLNA. First, we observed the formation of endogenous SST5 homo-dimers in GH3, A7, and M2 cells. Using the PLA approach combined with epitope tagging, we detected homo-dimers of human SST2 in GH3, A7, and M2 cells transiently co-expressing HA- and SNAP-tagged SST2. SST2 and SST5 can also form endogenous hetero-dimers in these cells. Interestingly, FLNA absence reduced the basal number of hetero-dimers (-36.8 ± 6.3% reduction of PLA events in M2, P < 0.05 vs. A7), and octreotide but not pasireotide promoted hetero-dimerization in both A7 and M2 (+20.0 ± 11.8% and +44.1 ± 16.3% increase of PLA events in A7 and M2, respectively, P < 0.05 vs. basal). Finally, immunofluorescence data showed that SST2 and SST5 recruitment at the plasma membrane and internalization are similarly induced by octreotide and pasireotide in GH3 and A7 cells. On the contrary, in M2 cells, octreotide failed to internalize both receptors whereas pasireotide promoted robust receptor internalization at shorter times than in A7 cells. In conclusion, we demonstrated that in GH3 cells SST2 and SST5 can form both homo- and hetero-dimers and that FLNA plays a role in the formation of SST2/SST5 hetero-dimers. Moreover, we showed that FLNA regulates SST2 and SST5 intracellular trafficking induced by octreotide and pasireotide.


Assuntos
Octreotida , Neoplasias Hipofisárias , Animais , Dimerização , Filaminas/metabolismo , Humanos , Octreotida/metabolismo , Octreotida/farmacologia , Neoplasias Hipofisárias/patologia , Ratos , Somatostatina
14.
J Thromb Haemost ; 20(11): 2666-2678, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36006037

RESUMO

BACKGROUND: Filaminopathies A are rare disorders affecting the brain, intestine, or skeleton, characterized by dominant X-linked filamin A (FLNA) gene mutations. Macrothrombocytopenia with functionally defective platelets is frequent. We have described a filaminopathy A male patient, exhibiting a C-terminal frame-shift FLNa mutation (Berrou et al., Arterioscler Thromb Vasc Biol. 2017;37:1087-1097). Contrasting with female patients, this male patient exhibited gain of platelet functions, including increased platelet aggregation, integrin αIIbß3 activation, and secretion at low agonist concentration, raising the issue of thrombosis risk. OBJECTIVES: Our goal is to assess the thrombotic potential of the patient FLNa mutation in an in vivo model. METHODS: We have established a mutant FlnA knock-in mouse model. RESULTS: The mutant FlnA mouse platelets phenocopied patient platelets, showing normal platelet count, lower expression level of mutant FlnA, and gain of platelet functions: increased platelet aggregation, secretion, and αIIbß3 activation, as well as increased spreading and clot retraction. Surprisingly, mutant FlnA mice exhibited a normal bleeding time, but with increased re-bleeding (77%) compared to wild type (WT) FlnA mice (27%), reflecting hemostatic plug instability. Again, in an in vivo thrombosis model, the occlusion time was not altered by the FlnA mutation, but arteriolar embolies were increased (7-fold more frequent in mutant FlnA mice versus WT mice), confirming thrombus instability. CONCLUSIONS: This study shows that the FlnA mutation found in the male patient induced gain of platelet functions in vitro, but thrombus instability in vivo. Implications for the role of FLNa in physiology of thrombus formation are discussed.


Assuntos
Hemostáticos , Trombose , Masculino , Feminino , Camundongos , Animais , Filaminas/genética , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Mutação com Ganho de Função , Trombose/genética , Trombose/metabolismo , Mutação
15.
Clin Neurol Neurosurg ; 221: 107386, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35961230

RESUMO

Skeletal muscle filaminopathy is caused by mutations in the gene encoding filamin C (FLNC). The phenotypes include both proximal and distal myopathy, of which proximal myopathy phenotype pathologically displays myofibrillar myopathy as mutated filamin C produces protein aggregates. FLNC-related myofibrillar myopathy usually starts in the fourth to fifth decade and often progresses to cause inability to walk, respiratory muscle weakness requiring nocturnal ventilation, and cardiac abnormalities, such as conduction blocks and diastolic dysfunction. We report a 65-year-old patient with myofibrillar myopathy caused by a novel heterozygous nonsense mutation in the dimerization domain of FLNC, in whom histopathological features were highlighted by histological and immunohistochemical studies. The reported patient showed slow progression of mild limb weakness since her childhood.


Assuntos
Códon sem Sentido , Miopatias Congênitas Estruturais , Dimerização , Feminino , Filaminas/genética , Humanos , Debilidade Muscular , Músculo Esquelético , Mutação/genética , Miopatias Congênitas Estruturais/genética , Linhagem , Agregados Proteicos
16.
Life Sci Alliance ; 5(12)2022 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-35922155

RESUMO

Podocytes are specialized epithelial cells of the kidney glomerulus and are an essential part of the filtration barrier. Because of their position, they are exposed to constant biomechanical forces such as shear stress and hydrostatic pressure. These forces increase during disease, resulting in podocyte injury. It is likely podocytes have adaptative responses to help buffer against deleterious mechanical force and thus reduce injury. However, these responses remain largely unknown. Here, using the <i>Drosophila</i> model, we show the mechanosensor Cheerio (dFilamin) provides a key protective role in nephrocytes. We found expression of an activated mechanosensitive variant of Cheerio rescued filtration function and induced compensatory and hypertrophic growth in nephrocytes depleted of the nephrocyte diaphragm proteins Sns or Duf. Delineating the protective pathway downstream of Cheerio we found repression of the Hippo pathway induces nephrocyte hypertrophy, whereas Hippo activation reversed the Cheerio-mediated hypertrophy. Furthermore, we find Yorkie was activated upon expression of active Cheerio. Taken together, our data suggest that Cheerio acts via the Hippo pathway to induce hypertrophic growth, as a protective response in abnormal nephrocytes.


Assuntos
Proteínas de Drosophila , Podócitos , Animais , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Filaminas/metabolismo , Hipertrofia/metabolismo , Podócitos/metabolismo
17.
Mol Cell Proteomics ; 21(10): 100406, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36030044

RESUMO

Latent liver stages termed hypnozoites cause relapsing Plasmodium vivax malaria infection and represent a major obstacle in the goal of malaria elimination. Hypnozoites are clinically undetectable, and presently, there are no biomarkers of this persistent parasite reservoir in the human liver. Here, we have identified parasite and human proteins associated with extracellular vesicles (EVs) secreted from in vivo infections exclusively containing hypnozoites. We used P. vivax-infected human liver-chimeric (huHEP) FRG KO mice treated with the schizonticidal experimental drug MMV048 as hypnozoite infection model. Immunofluorescence-based quantification of P. vivax liver forms showed that MMV048 removed schizonts from chimeric mice livers. Proteomic analysis of EVs derived from FRG huHEP mice showed that human EV cargo from infected FRG huHEP mice contain inflammation markers associated with active schizont replication and identified 66 P. vivax proteins. To identify hypnozoite-specific proteins associated with EVs, we mined the proteome data from MMV048-treated mice and performed an analysis involving intragroup and intergroup comparisons across all experimental conditions followed by a peptide compatibility analysis with predicted spectra to warrant robust identification. Only one protein fulfilled this stringent top-down selection, a putative filamin domain-containing protein. This study sets the stage to unveil biological features of human liver infections and identify biomarkers of hypnozoite infection associated with EVs.


Assuntos
Vesículas Extracelulares , Malária Vivax , Parasitos , Humanos , Camundongos , Animais , Malária Vivax/tratamento farmacológico , Malária Vivax/parasitologia , Plasmodium vivax , Proteômica , Proteoma , Filaminas , Fígado , Biomarcadores , Espectrometria de Massas
18.
Oxid Med Cell Longev ; 2022: 8956636, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35832491

RESUMO

Mutations of filamin B (FLNB) gene can lead to a spectrum of autosomal skeletal malformations including spondylocarpotarsal syndrome (SCT), Larsen syndrome (LRS), type I atelosteogenesis (AO1), type III atelosteogenesis (AO3), and boomerang dysplasia (BD). Among them, LRS is milder while BD causes a more severe phenotype. However, the molecular mechanism underlying the differences in clinical phenotypes of different FLNB variants has not been fully determined. Here, we presented two patients suffering from autosomal dominant LRS and autosomal recessive vitamin D-dependent rickets type IA (VDDR-IA). Whole-exome sequencing revealed two novel missense variants in FLNB, c.4846A>G (p.T1616A) and c.7022T>G (p.I2341R), which are located in repeat 15 and 22 of filamin B, respectively. The expression of FLNBI2341R in the muscle tissue from our LRS patient was remarkably increased. And in vitro studies showed that both variants led to a lack of filopodia and accumulation of the mutants in the perinuclear region in HEK293 cells. We also found that c.4846A>G (p.T1616A) and c.7022T>G (p.I2341R) regulated endochondral osteogenesis in different ways. c.4846A>G (p.T1616A) activated AKT pathways through inhibiting SHIP2, suppressed the Smad3 pathway, and impaired the expression of Runx2 in both Saos-2 and ATDC5 cells. c.7022T>G (p.I2341R) activated both AKT and Smad3 pathways and increased the expression of Runx2 in Saos-2 cells, while in ATDC5 cells it activated AKT pathways through inhibiting SHIP2, suppressed the Smad3 pathway, and reduced the expression of Runx2. Our study demonstrated the pathogenic mechanisms of two novel FLNB variants in two different clinical settings and proved that FLNB variants could not only directly cause skeletal malformations but also worsen skeletal symptoms in the setting of other skeletal diseases. Besides, FLNB variants differentially affect skeletal development which contributes to clinical heterogeneity of FLNB-related disorders.


Assuntos
Subunidade alfa 1 de Fator de Ligação ao Core , Filaminas , Osteocondrodisplasias , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Nanismo/metabolismo , Facies , Filaminas/genética , Filaminas/metabolismo , Células HEK293 , Humanos , Osteocondrodisplasias/genética , Osteocondrodisplasias/metabolismo , Osteocondrodisplasias/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo
19.
J Card Surg ; 37(10): 3408-3412, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35819109

RESUMO

We report the case of a 28 years old woman with periventricular nodular heterotopia, due to Filamin A mutation. She had an asymmetrical aneurysm of the aortic root, involving, above all, noncoronary Valsalva sinus. She was asymptomatic and she had moderate aortic regurgitation. Reimplantation of the aortic valve with replacement of the aortic root was successfully accomplished. Filamin A is a protein that is encoded by the FLNA gene, which shows X-linked dominant inheritance. This protein is involved in neuronal migration, angiogenesis, cytoskeleton regulation, and cell signaling. Therefore, mutations of FLNA gene might result in brain, blood vessels, heart, and connective tissue disorders. A miscellany of cardiovascular abnormalities could be present in this subset of patients; cardiac symptoms may precede neurological manifestations. Aorta seems to be frequently affected. Consequently, in presence of FLNA gene mutations, cardiovascular evaluation should include vascular magnetic resonance imaging or computed tomography scan.


Assuntos
Aneurisma da Aorta Torácica , Heterotopia Nodular Periventricular , Adulto , Encéfalo , Feminino , Filaminas/genética , Humanos , Mutação , Heterotopia Nodular Periventricular/genética , Heterotopia Nodular Periventricular/patologia , Heterotopia Nodular Periventricular/cirurgia
20.
EMBO J ; 41(17): e109205, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35880301

RESUMO

Patient-derived organoids and cellular spheroids recapitulate tissue physiology with remarkable fidelity. We investigated how engagement with a reconstituted basement membrane in three dimensions (3D) supports the polarized, stress resilient tissue phenotype of mammary epithelial spheroids. Cells interacting with reconstituted basement membrane in 3D had reduced levels of total and actin-associated filamin and decreased cortical actin tension that increased plasma membrane protrusions to promote negative plasma membrane curvature and plasma membrane protein associations linked to protein secretion. By contrast, cells engaging a reconstituted basement membrane in 2D had high cortical actin tension that forced filamin unfolding and endoplasmic reticulum (ER) associations. Enhanced filamin-ER interactions increased levels of PKR-like ER kinase effectors and ER-plasma membrane contact sites that compromised calcium homeostasis and diminished cell viability. Consequently, cells with decreased cortical actin tension had reduced ER stress and survived better. Consistently, cortical actin tension in cellular spheroids regulated polarized basement membrane membrane deposition and sensitivity to exogenous stress. The findings implicate cortical actin tension-mediated filamin unfolding in ER function and underscore the importance of tissue mechanics in organoid homeostasis.


Assuntos
Actinas , Retículo Endoplasmático , Actinas/metabolismo , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático , Células Epiteliais/metabolismo , Filaminas/metabolismo , Fenótipo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...