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1.
Neurobiol Aging ; 104: 111.e1-111.e4, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33875291

RESUMO

Genetic risk factors are occasionally shared between different neurodegenerative diseases. Previous studies have linked ANG, a gene encoding angiogenin, to both Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS). Functional studies suggest ANG plays a neuroprotective role in both PD and amyotrophic lateral sclerosis by reducing cell death. We further explored the genetic association between ANG and PD by analyzing genotype data from the International Parkinson's Disease Genomics Consortium (14,671 cases and 17,667 controls) and whole genome sequencing data from the Accelerating Medicines Partnership - Parkinson's disease initiative (AMP-PD, https://amp-pd.org/) (1,647 cases and 1,050 controls). Our analysis did not replicate the findings of previous studies and identified no significant association between ANG variants and PD risk.


Assuntos
Variação Genética/genética , Doença de Parkinson/genética , Ribonuclease Pancreático/genética , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Morte Celular , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Doença de Parkinson/patologia , Ribonuclease Pancreático/fisiologia , Fatores de Risco , Sequenciamento Completo do Genoma
2.
Diabetes ; 69(7): 1503-1517, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32321760

RESUMO

Diabetic retinopathy is a potentially blinding eye disease that threatens the vision of one-ninth of patients with diabetes. Progression of the disease has long been attributed to an initial dropout of pericytes that enwrap the retinal microvasculature. Revealed through retinal vascular digests, a subsequent increase in basement membrane bridges was also observed. Using cell-specific markers, we demonstrate that pericytes rather than endothelial cells colocalize with these bridges. We show that the density of bridges transiently increases with elevation of Ang-2, PDGF-BB, and blood glucose; is rapidly reversed on a timescale of days; and is often associated with a pericyte cell body located off vessel. Cell-specific knockout of KLF4 in pericytes fully replicates this phenotype. In vivo imaging of limbal vessels demonstrates pericyte migration off vessel, with rapid pericyte filopodial-like process formation between adjacent vessels. Accounting for off-vessel and on-vessel pericytes, we observed no pericyte loss relative to nondiabetic control retina. These findings reveal the possibility that pericyte perturbations in location and process formation may play a role in the development of pathological vascular remodeling in diabetic retinopathy.


Assuntos
Retinopatia Diabética/etiologia , Homeostase , Hiperglicemia/patologia , Pericitos/fisiologia , Animais , Antígenos/análise , Becaplermina/fisiologia , Colágeno Tipo IV/análise , Diabetes Mellitus Experimental/tratamento farmacológico , Insulina/uso terapêutico , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Cadeias Pesadas de Miosina/análise , Pericitos/efeitos dos fármacos , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Proteoglicanas/análise , Ribonuclease Pancreático/fisiologia , Estreptozocina
3.
PLoS One ; 14(8): e0220037, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31393891

RESUMO

Human genome contains a group of more than a dozen similar genes with diverse biological functions including antiviral, antibacterial and angiogenesis activities. The characterized gene products of this group show significant sequence similarity and a common structural fold associated with binding and cleavage of ribonucleic acid (RNA) substrates. Therefore, these proteins have been categorized as members of human pancreatic-type ribonucleases (hRNases). hRNases differ in cell/tissue localization and display distinct substrate binding preferences and a wide range of ribonucleolytic catalytic efficiencies. Limited information is available about structural and dynamical properties that influence this diversity among these homologous RNases. Here, we use computer simulations to characterize substrate interactions, electrostatics and dynamical properties of hRNases 1-7 associated with binding to two nucleotide substrates (ACAC and AUAU). Results indicate that even with complete conservation of active-site catalytic triad associated with ribonucleolytic activity, these enzymes show significant differences in substrate interactions. Detailed characterization suggests that in addition to binding site electrostatic and van der Waals interactions, dynamics of distal regions may also play a role in binding. Another key insight is that a small difference in temperature of 300 K (used in experimental studies) and 310 K (physiological temperature) shows significant changes in enzyme-substrate interactions.


Assuntos
Sítios de Ligação/fisiologia , Ribonuclease Pancreático/metabolismo , Ribonuclease Pancreático/ultraestrutura , Catálise , Domínio Catalítico/fisiologia , Simulação por Computador , Humanos , Cinética , Nucleotídeos/metabolismo , RNA/metabolismo , Ribonuclease Pancreático/fisiologia , Ribonucleases/metabolismo , Eletricidade Estática , Especificidade por Substrato/fisiologia
4.
Fundam Clin Pharmacol ; 33(6): 659-669, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31044460

RESUMO

Thalidomide, a well-known immunomodulatory compound, has an anti-angiogenic activity, which may be utilized for the treatment of angiogenesis-related diseases such as hemangioendothelioma. The aim of the present study was to investigate both the antitumor role of thalidomide on hemangioendothelioma and the underlying mechanism. By using the xenograft mouse model, we found that thalidomide can inhibit the progression of hemangioendothelioma in vivo. Moreover, thalidomide shows no effect on the proliferation of hemangioendothelioma endothelial cell (EOMA), but significantly impairs the pro-angiogenic capacity of the EOMA cells in vitro. By qRT-PCR screening, we observed that the expression of angiogenin was downregulated by thalidomide treatment. We next performed tissue array analysis and found a positive correlation between angiogenin expression level and hemangioendothelioma occurrence in patients. Moreover, we confirmed that the antitumoral role of thalidomide is dependent on angiogenin expression both in vivo and in vitro. Taken together, we concluded that thalidomide can inhibit the progression of hemangioendothelioma by downregulating the expression of pro-angiogenic factor angiogenin and therefore can be used as a potent therapeutic to treat hemangioendothelioma.


Assuntos
Hemangioendotelioma/prevenção & controle , Ribonuclease Pancreático/antagonistas & inibidores , Talidomida/farmacologia , Animais , Carcinogênese , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Hemangioendotelioma/patologia , Humanos , Camundongos , Ribonuclease Pancreático/fisiologia
5.
Methods ; 152: 18-22, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29777751

RESUMO

MicroRNAs (miRNAs) comprise a class of small non-coding RNAs that regulate the stability and/or translatability of most protein-coding transcripts. Steady-state levels of mature miRNAs can be controlled through mechanisms that influence their biogenesis and/or decay rates. Pathways that mediate mature miRNA decay are less well understood than those that mediate miRNA biogenesis. We recently described Tudor-staphylococcal/micrococcal-like nuclease (TSN)-mediated miRNA decay (TumiD) as a cellular pathway that promotes the sequence-specific endonucleolytic decay of miRNAs that harbor a CA and/or UA dinucleotide. Here, we describe an in vitro assay for evaluating the susceptibility of AGO2-loaded miRNAs to degradation by different classes of nucleases. This in vitro approach can be used to complement in vivo studies that aim to identify novel miRNA decay factors.


Assuntos
Proteínas Argonautas/metabolismo , MicroRNAs/metabolismo , Estabilidade de RNA , Proteínas Argonautas/química , Bioquímica/métodos , Endonucleases , Células HEK293 , Humanos , MicroRNAs/química , Proteínas Nucleares/metabolismo , Proteínas Nucleares/fisiologia , Ribonuclease Pancreático/metabolismo , Ribonuclease Pancreático/fisiologia
6.
J Am Soc Nephrol ; 27(9): 2670-83, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26823555

RESUMO

The ribonuclease angiogenin is a component of the mammalian stress response, and functions in both cell-autonomous and non-cell-autonomous ways to promote tissue adaptation to injury. We recently showed that angiogenin regulates tissue homeostasis during AKI associated with endoplasmic reticulum (ER) stress through the production of transfer RNA fragments that interfere with translation initiation and thereby alleviate ER stress. However, whether the paracrine signaling mediated by angiogenin secretion is a genuine component of the ER stress response to kidney injury is unknown. Here, we explored the molecular mechanisms by which angiogenin is secreted upon ER stress, and determined how it modulates the inflammatory microenvironment. In cultured renal epithelial cells, ER stress specifically induced angiogenin secretion under the selective control of inositol-requiring enzyme 1α, a key activator of the unfolded protein response. The transcription factors spliced X-box-binding protein 1 and p65, which are activated by inositol-requiring enzyme 1α upon ER stress, each bound the angiogenin promoter and controlled the amount of angiogenin secreted. Furthermore, p65 promoted angiogenin transcription in an ER stress-dependent manner. Similar to secretion of the ER stress-induced proinflammatory cytokine IL-6, secretion of angiogenin required the ER-Golgi pathway. Notably, incubation of human macrophages with angiogenin promoted macrophage reprogramming toward an activated and proinflammatory phenotype. In patients, angiogenin expression increased upon renal inflammation, and the urinary concentration of angiogenin correlated with the extent of immune-mediated kidney injury. Collectively, our data identify angiogenin as a mediator of the ER stress-dependent inflammatory response and as a potential noninvasive biomarker of AKI.


Assuntos
Rim/metabolismo , Transdução de Sinais , Resposta a Proteínas não Dobradas/fisiologia , Animais , Células Cultivadas , Estresse do Retículo Endoplasmático/fisiologia , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Ribonuclease Pancreático/metabolismo , Ribonuclease Pancreático/fisiologia
7.
Acta Biochim Biophys Sin (Shanghai) ; 48(5): 399-410, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26705141

RESUMO

As a member of the vertebrate-specific secreted ribonucleases, angiogenin (ANG) was first isolated and identified solely by its ability to induce new blood vessel formation, and now, it has been recognized to play important roles in various physiological and pathological processes through regulating cell proliferation, survival, migration, invasion, and/or differentiation. ANG exhibits very weak ribonucleolytic activity that is critical for its biological functions, and exerts its functions through activating different signaling transduction pathways in different target cells. A series of recent studies have indicated that ANG contributes to cellular nucleic acid metabolism. Here, we comprehensively review the results of studies regarding the structure, mechanism, and function of ANG over the past three decades. Moreover, current problems and future research directions of ANG are discussed. The understanding of the function and mechanism of ANG in a wide context will help to better delineate its roles in diseases, especially in cancer and neurodegenerative diseases.


Assuntos
Ribonuclease Pancreático , Animais , Carcinogênese , Humanos , Tolerância Imunológica , Modelos Moleculares , Neovascularização Fisiológica , Doenças Neurodegenerativas/etiologia , Ácidos Nucleicos/metabolismo , Mapas de Interação de Proteínas , Ribonuclease Pancreático/química , Ribonuclease Pancreático/genética , Ribonuclease Pancreático/fisiologia , Transdução de Sinais
8.
J Biol Chem ; 289(38): 25996-26006, 2014 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-25078100

RESUMO

Mounting evidence suggests that human pancreatic ribonuclease (RNase 1) plays important roles in vivo, ranging from regulating blood clotting and inflammation to directly counteracting tumorigenic cells. Understanding these putative roles has been pursued with continual comparisons of human RNase 1 to bovine RNase A, an enzyme that appears to function primarily in the ruminant gut. Our results imply a different physiology for human RNase 1. We demonstrate distinct functional differences between human RNase 1 and bovine RNase A. Moreover, we characterize another RNase 1 homolog, bovine brain ribonuclease, and find pronounced similarities between that enzyme and human RNase 1. We report that human RNase 1 and bovine brain ribonuclease share high catalytic activity against double-stranded RNA substrates, a rare quality among ribonucleases. Both human RNase 1 and bovine brain RNase are readily endocytosed by mammalian cells, aided by tight interactions with cell surface glycans. Finally, we show that both human RNase 1 and bovine brain RNase are secreted from endothelial cells in a regulated manner, implying a potential role in vascular homeostasis. Our results suggest that brain ribonuclease, not RNase A, is the true bovine homolog of human RNase 1, and provide fundamental insight into the ancestral roles and functional adaptations of RNase 1 in mammals.


Assuntos
Ribonuclease Pancreático/química , Animais , Encéfalo/enzimologia , Bovinos , Células Cultivadas , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Cinética , Lipossomos/química , Ligação Proteica , Transporte Proteico , Estabilidade de RNA , RNA de Cadeia Dupla/química , Ribonuclease Pancreático/fisiologia
9.
FEBS J ; 281(16): 3559-75, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24966023

RESUMO

Comparative studies on homologous proteins can provide knowledge on how limited changes in the primary structure find their expression in large effects on catalytic activity, stability or the folding behavior. For more than half a century, members of the ribonuclease A superfamily have been the subject of a myriad of studies on protein folding and stability. Both the unfolding and refolding kinetics as well as the structure of several folding intermediates of ribonuclease A have been characterized in detail. Moreover, the RNA-degrading activity of these enzymes provides a basis for their cytotoxicity, which renders them potential tumor therapeutics. Because amphibian ribonuclease A homologues evade the human ribonuclease inhibitor, they emerged as particularly promising candidates. Interestingly, the amphibian ribonuclease A homologues investigated to date are more stable than the mammalian homologues. Nevertheless, despite the generation of numerous genetically engineered variants, knowledge of the folding of amphibian ribonuclease A homologues remains rather limited. An exception is onconase, a ribonuclease A homologue from Rana pipiens, which has been characterized in detail. This review summarizes the data on the unfolding and refolding kinetics and pathways, as well on the stability of amphibian ribonuclease A homologues compared with those of ribonuclease A, the best known member of this superfamily.


Assuntos
Proteínas de Anfíbios/química , Ribonuclease Pancreático/química , Proteínas de Anfíbios/fisiologia , Animais , Estabilidade Enzimática , Humanos , Cinética , Oxirredução , Dobramento de Proteína , Ribonuclease Pancreático/fisiologia , Homologia de Sequência de Aminoácidos , Temperatura de Transição
10.
J Oral Pathol Med ; 42(8): 606-11, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23432607

RESUMO

BACKGROUND: Angiogenin (ANG) is a member of the ribonuclease superfamily and of medical interest largely because it supports the growth of primary and metastatic malignancies. This study is the first to investigate the potential role of ANG in tongue carcinoma neo-angiogenesis and cancer cell proliferation. METHODS: Angiogenin expression (in carcinoma cells and endothelial intratumor vessel cells), CD105-assessed micro-vessel density (MVD), and MIB-1 expression were correlated with prognostic parameters in 28 primarily consecutively operated pT1-T2 tongue carcinomas (squamous cell carcinoma [SCC]). Whenever feasible, a computer-based image analysis system was used for the immunohistochemical reaction analysis. RESULTS: No significant correlations emerged between ANG expression in the tongue carcinoma cells or endothelial intratumor vessel cells and tongue SCC recurrence rate or disease-free survival (DFS). ANG expression was also unrelated to CD105-assessed MVD or MIB-1 expression. Conversely, CD105-assessed MVD correlated directly with recurrence rate (P = 0.02) and DFS was significantly shorter in cases with CD105-assessed MVD >167 micro-vessels/mm(2) than in those with CD105-assessed MVD ≤167 micro-vessels/mm(2) (P = 0.042). CONCLUSIONS: Our results support the hypothesis that CD105-assessed MVD would be a valuable parameter for predicting which patients with tongue SCC are at greatest risk of disease recurrence. Despite our study results, the role of ANG in tongue carcinoma warrants further investigation in larger series.


Assuntos
Indutores da Angiogênese/farmacologia , Carcinoma de Células Escamosas/irrigação sanguínea , Neovascularização Patológica/patologia , Ribonuclease Pancreático/fisiologia , Neoplasias da Língua/irrigação sanguínea , Indutores da Angiogênese/análise , Antígenos CD/análise , Proliferação de Células/efeitos dos fármacos , Intervalo Livre de Doença , Endoglina , Células Endoteliais/patologia , Endotélio Vascular/patologia , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Antígeno Ki-67/análise , Microvasos/patologia , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Prognóstico , Receptores de Superfície Celular/análise , Ribonuclease Pancreático/análise , Resultado do Tratamento
11.
J Immunol ; 190(6): 2536-43, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23382559

RESUMO

TLR7 activation is implicated in the pathogenesis of systemic lupus erythematosus. Mice that overexpress TLR7 develop a lupus-like disease with autoantibodies and glomerulonephritis and early death. To determine whether degradation of the TLR7 ligand RNA would alter the course of disease, we created RNase A transgenic (Tg) mice. We then crossed the RNase Tg to TLR7 Tg mice to create TLR7 × RNase double Tg (DTg) mice. DTg mice had a significantly increased survival associated with reduced activation of T and B lymphocytes and reduced kidney deposition of IgG and C3. We observed massive hepatic inflammation and cell death in TLR7 Tg mice. In contrast, hepatic inflammation and necrosis were strikingly reduced in DTg mice. These findings indicate that high concentrations of serum RNase protect against immune activation and inflammation associated with TLR7 stimulation and that RNase may be a useful therapeutic strategy in the prevention or treatment of inflammation in systemic lupus erythematosus and, possibly, liver diseases.


Assuntos
Regulação para Baixo/genética , Regulação para Baixo/imunologia , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/genética , Ribonuclease Pancreático/genética , Receptor 7 Toll-Like/biossíntese , Receptor 7 Toll-Like/genética , Regulação para Cima/genética , Regulação para Cima/imunologia , Animais , Bovinos , Células Cultivadas , Células-Tronco Embrionárias , Hepatite/enzimologia , Hepatite/imunologia , Hepatite/patologia , Humanos , Inflamação/enzimologia , Inflamação/imunologia , Inflamação/prevenção & controle , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/mortalidade , Lúpus Eritematoso Sistêmico/prevenção & controle , Masculino , Glicoproteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ribonuclease Pancreático/sangue , Ribonuclease Pancreático/fisiologia , Baço/enzimologia , Baço/imunologia , Baço/patologia , Análise de Sobrevida , Receptor 7 Toll-Like/fisiologia
12.
J Neurosci Res ; 90(12): 2227-36, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22930493

RESUMO

Parkinson's disease (PD) is the second most common form of neurodegeneration among the elderly population. PD is clinically characterized by tremors, rigidity, slowness of movement, and postural imbalance. Interestingly, a significant association has been demonstrated between PD and low levels of vitamin D in the serum, and vitamin D supplement appears to have a beneficial clinical effect on PD. Genetic studies have provided the opportunity to determine which proteins link vitamin D to PD pathology, e.g., Nurr1 gene, toll-like receptor, gene related to lipid disorders, vascular endothelial factor, tyrosine hydroxylase, and angiogenin. Vitamin D also exerts its effects on cancer through nongenomic factors, e.g., bacillus Calmette-Guerin vaccination, interleukin-10, Wntß-catenin signaling pathways, mitogen-activated protein kinase pathways, and the reduced form of the nicotinamide adenine dinucleotide phosphate. In conclusion, vitamin D might have a beneficial role in PD. Calcitriol is best used for PD because it is the active form of the vitamin D(3) metabolite and modulates inflammatory cytokine expression. Further investigation with calcitriol in PD is needed.


Assuntos
Doença de Parkinson/etiologia , Vitamina D/fisiologia , Animais , Vacina BCG/uso terapêutico , Calcitriol/efeitos adversos , Calcitriol/uso terapêutico , Colesterol/metabolismo , Estudos de Associação Genética , Humanos , Hipercalcemia/induzido quimicamente , Camundongos , Camundongos Knockout , NADPH Oxidases/fisiologia , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/deficiência , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 2 do Grupo A da Subfamília 4 de Receptores Nucleares/fisiologia , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Doença de Parkinson/prevenção & controle , Transtornos Parkinsonianos/etiologia , Transtornos Parkinsonianos/genética , Ratos , Receptores de Calcitriol/deficiência , Receptores de Calcitriol/fisiologia , Ribonuclease Pancreático/fisiologia , Transdução de Sinais/fisiologia , Receptores Toll-Like/fisiologia , Tirosina 3-Mono-Oxigenase/fisiologia , Fator A de Crescimento do Endotélio Vascular/fisiologia , Vitamina D/uso terapêutico , Deficiência de Vitamina D/complicações
13.
J Neurosci ; 32(15): 5024-38, 2012 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-22496549

RESUMO

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disorder affecting motoneurons. Mutations in angiogenin, encoding a member of the pancreatic RNase A superfamily, segregate with ALS. We previously demonstrated that angiogenin administration shows promise as a neuroprotective therapeutic in studies using transgenic ALS mice and primary motoneuron cultures. Its mechanism of action and target cells in the spinal cord, however, are largely unknown. Using mixed motoneuron cultures, motoneuron-like NSC34 cells, and primary astroglia cultures as model systems, we here demonstrate that angiogenin is a neuronally secreted factor that is endocytosed by astroglia and mediates neuroprotection in paracrine. We show that wild-type angiogenin acts unidirectionally to induce RNA cleavage in astroglia, while the ALS-associated K40I mutant is also secreted and endocytosed, but fails to induce RNA cleavage. Angiogenin uptake into astroglia requires heparan sulfate proteoglycans, and engages clathrin-mediated endocytosis. We show that this uptake mechanism exists for mouse and human angiogenin, and delivers a functional RNase output. Moreover, we identify syndecan 4 as the angiogenin receptor mediating the selective uptake of angiogenin into astroglia. Our data provide new insights into the paracrine activities of angiogenin in the nervous system, and further highlight the critical role of non-neuronal cells in the pathogenesis of ALS.


Assuntos
Astrócitos/metabolismo , Astrócitos/fisiologia , Neurônios Motores/metabolismo , Clivagem do RNA/fisiologia , Ribonuclease Pancreático/metabolismo , Ribonuclease Pancreático/fisiologia , Animais , Western Blotting , Sobrevivência Celular/fisiologia , Células Cultivadas , Clatrina/fisiologia , Meios de Cultivo Condicionados , Endocitose/fisiologia , Feminino , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fármacos Neuroprotetores , Comunicação Parácrina/fisiologia , Ligação Proteica , Reação em Cadeia da Polimerase em Tempo Real , Sindecana-4/metabolismo , Transfecção
14.
PLoS One ; 7(2): e32479, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22384259

RESUMO

BACKGROUND: Mutations in the coding region of angiogenin (ANG) gene have been found in patients suffering from Amyotrophic Lateral Sclerosis (ALS). Neurodegeneration results from the loss of angiogenic ability of ANG (protein coded by ANG). In this work, we performed extensive molecular dynamics (MD) simulations of wild-type ANG and disease associated ANG variants to elucidate the mechanism behind the loss of ribonucleolytic activity and nuclear translocation activity, functions needed for angiogenesis. METHODOLOGY/PRINCIPAL FINDINGS: MD simulations were carried out to study the structural and dynamic differences in the catalytic site and nuclear localization signal residues between WT-ANG (Wild-type ANG) and six mutants. Variants K17I, S28N, P112L and V113I have confirmed association with ALS, while T195C and A238G single nucleotide polymorphisms (SNPs) encoding L35P and K60E mutants respectively, have not been associated with ALS. Our results show that loss of ribonucleolytic activity in K17I is caused by conformational switching of the catalytic residue His114 by 99°. The loss of nuclear translocation activity of S28N and P112L is caused by changes in the folding of the residues (31)RRR(33) that result in the reduction in solvent accessible surface area (SASA). Consequently, we predict that V113I will exhibit loss of angiogenic properties by loss of nuclear translocation activity and L35P by loss of both ribonucleolytic activity and nuclear translocation activity. No functional loss was inferred for K60E. The MD simulation results were supported by hydrogen bond interaction analyses and molecular docking studies. CONCLUSIONS/SIGNIFICANCE: Conformational switching of catalytic residue His114 seems to be the mechanism causing loss of ribonucleolytic activity and reduction in SASA of nuclear localization signal residues (31)RRR(33) results in loss of nuclear translocation activity in ANG mutants. Therefore, we predict that L35P mutant, would exhibit loss of angiogenic functions, and hence would correlate with ALS while K60E would not show any loss.


Assuntos
Esclerose Lateral Amiotrófica/genética , Mutação , Ribonuclease Pancreático/genética , Transporte Ativo do Núcleo Celular , Esclerose Lateral Amiotrófica/metabolismo , Cristalografia por Raios X/métodos , Variação Genética , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Simulação de Dinâmica Molecular , Neovascularização Patológica , Conformação Proteica , Ribonuclease Pancreático/química , Ribonuclease Pancreático/fisiologia , Fatores de Risco , Transdução de Sinais , Solventes/química , Propriedades de Superfície
15.
Hematol Oncol ; 30(3): 131-6, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21919032

RESUMO

Angiogenesis is a complex process essential for the growth, invasion, and metastasis of various malignant tumours, including multiple myeloma (MM). Various angiogenic cytokines have been implicated in the angiogenic process. Among them, platelet-derived growth factor-AB (PDGF-AB) has been reported to be a potent stimulator of angiogenesis in many solid tumours and haematological malignancies, including MM. The aim of the study was to investigate the relationship between PDGF-AB, microvascular density (MVD), and various angiogenic cytokines, such as basic fibroblast growth factor (b-FGF), angiogenin (ANG), and interleukin-6 (IL-6), in MM patients. Forty-seven MM patients before treatment, 22 of whom were in plateau phase, were studied. We determined the serum levels of the aforementioned cytokines and MVD in bone marrow biopsies before and after treatment. Mean serum values of PDGF-AB, b-FGF, ANG, and MVD were significantly higher in patients compared with controls and with increasing disease stage. Significant positive correlations were observed between serum PDGF-AB, ANG, and IL-6 levels and MVD. Furthermore, we found significant positive correlations between PDGF-AB and b-FGF, IL-6, ANG, and ß2 microglobulin. We also found that patients with high MVD had statistically significantly higher serum levels of PDGF-AB when a median MVD value of 7.7 was used as the cutoff point. Furthermore, a significant difference was found in serum levels of PDGF-AB between pre- and post-treatment patients. Finally, survival time was significantly higher in the low MVD group versus the high MVD group (76 vs 51 months). Our results showed that there is a strong positive correlation between PDGF-AB and the studied angiogenic cytokines and MVD. It seems that PDGF-AB plays a role in the complex network of cytokines inducing bone marrow neovascularization in patients with MM.


Assuntos
Fator 2 de Crescimento de Fibroblastos/fisiologia , Interleucina-6/fisiologia , Microvasos/patologia , Mieloma Múltiplo/fisiopatologia , Proteínas de Neoplasias/fisiologia , Neovascularização Patológica/fisiopatologia , Fator de Crescimento Derivado de Plaquetas/fisiologia , Ribonuclease Pancreático/fisiologia , Microglobulina beta-2/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Medula Óssea/irrigação sanguínea , Medula Óssea/patologia , Progressão da Doença , Feminino , Fator 2 de Crescimento de Fibroblastos/sangue , Humanos , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/sangue , Neovascularização Patológica/sangue , Fator de Crescimento Derivado de Plaquetas/análise , Ribonuclease Pancreático/sangue , Microglobulina beta-2/sangue
17.
Mol Cell ; 43(4): 613-23, 2011 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-21855800

RESUMO

Angiogenin is a stress-activated ribonuclease that cleaves tRNA within anticodon loops to produce tRNA-derived stress-induced fragments (tiRNAs). Transfection of natural or synthetic tiRNAs inhibits protein synthesis and triggers the phospho-eIF2α-independent assembly of stress granules (SGs), essential components of the stress response program. We show that selected tiRNAs inhibit protein synthesis by displacing eIF4G/eIF4A from uncapped > capped RNAs. tiRNAs also displace eIF4F, but not eIF4E:4EBP1, from isolated m(7)G cap. We identify a terminal oligoguanine motif that is required to displace the eIF4F complex, inhibit translation, and induce SG assembly. We show that the tiRNA-associated translational silencer YB-1 contributes to angiogenin-, tiRNA-, and oxidative stress-induced translational repression. Our data reveal some of the mechanisms by which stress-induced tRNA cleavage inhibits protein synthesis and activates a cytoprotective stress response program.


Assuntos
Iniciação Traducional da Cadeia Peptídica , RNA de Transferência/fisiologia , Ribonuclease Pancreático/fisiologia , Linhagem Celular , Fator de Iniciação Eucariótico 4G/metabolismo , Fator de Iniciação Eucariótico 4G/fisiologia , Humanos , RNA de Transferência/química , Estresse Fisiológico , Proteína 1 de Ligação a Y-Box/metabolismo , Proteína 1 de Ligação a Y-Box/fisiologia
18.
Front Biosci (Landmark Ed) ; 16(2): 531-8, 2011 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-21196186

RESUMO

Metastatic, rather than primary tumours are responsible for ninety percent cancer deaths. Despite significant advances in the understanding of molecular and cellular mechanisms in tumour metastases, there are limitations in preventive treatment of metastatic tumours. Much evidence arising from laboratory and clinical studies suggests that growth factors and their receptors are implicated in cancer metastases development. We review the origin and production of growth factors and their receptors in all stages of cancer metastases including epithelial-mesenchymal transition, cancer cell invasion and migration, survival within the circulation, seeding at distant organs and metastatic tumour angiogenesis. The functions of growth factors and their receptors are also discussed. This review presents the efforts made in understanding this challenge to aid in the development of new treatment strategies for cancer metastases.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/fisiologia , Metástase Neoplásica/fisiopatologia , Neoplasias/patologia , Receptores de Fatores de Crescimento/fisiologia , Angiopoietinas/fisiologia , Animais , Apoptose , Movimento Celular , Fator de Crescimento Epidérmico/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Receptores ErbB/fisiologia , Glucose-6-Fosfato Isomerase/fisiologia , Fator de Crescimento de Hepatócito/fisiologia , Humanos , Fator de Crescimento Insulin-Like I/fisiologia , Interleucina-8/fisiologia , Complexos Multienzimáticos/fisiologia , Invasividade Neoplásica/fisiopatologia , Inoculação de Neoplasia , Células Neoplásicas Circulantes/patologia , Neovascularização Patológica/fisiopatologia , Fosfodiesterase I/fisiologia , Diester Fosfórico Hidrolases , Pirofosfatases/fisiologia , Receptor IGF Tipo 1/fisiologia , Ribonuclease Pancreático/fisiologia , Proteínas Smad/fisiologia , Fatores de Transcrição da Família Snail , Fatores de Transcrição/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Fator de Necrose Tumoral alfa/fisiologia
19.
Oral Oncol ; 46(9): 648-53, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20656548

RESUMO

Squamous cell carcinoma of the head and neck (HNSCC) is the eighth most common disease, affecting approximately 640,000 patients worldwide each year. Despite recent advances in surgery, radiotherapy, and chemotherapy, the overall cure for patients with HNSCC has remained at less than 50% for many decades. Patients with recurrent and metastatic disease have a median survival of only 6-10 months. Systemic chemotherapy is the only treatment option for those patients. New treatment options are thus desperately needed to supplement, complement, or replace currently available therapies. New agents that target molecular and cellular pathways of the disease pathogenesis of HNSCC are promising candidates. One class of these new agents is angiogenesis inhibitors that have been proven effective in the treatment of advanced colorectal, breast, and non-small cell lung cancers. Similar to other solid tumors, angiogenesis plays an important role in the pathogenesis of HNSCC. A number of angiogenic factors including vascular endothelial growth factor (VEGF) and angiogenin (ANG) have been shown to be significantly upregulated in HNSCC. Among them, ANG is unique in which it is a ribonuclease that regulates ribosomal RNA (rRNA) transcription. ANG-stimulated rRNA transcription has been shown to be a general requirement for angiogenesis induced by other angiogenic factors. ANG inhibitors have been demonstrated to inhibit angiogenesis and tumor growth induced not only by ANG but also by other angiogenic factors. As the role of ANG in HNSCC is being unveiled, the therapeutic potential of ANG inhibitors in HNSCC is expected.


Assuntos
Inibidores da Angiogênese/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Proteínas de Neoplasias/antagonistas & inibidores , RNA Ribossômico/metabolismo , Ribonuclease Pancreático/antagonistas & inibidores , Carcinoma de Células Escamosas/metabolismo , Feminino , Terapia Genética , Neoplasias de Cabeça e Pescoço/metabolismo , Humanos , Masculino , Proteínas de Neoplasias/fisiologia , Ribonuclease Pancreático/fisiologia
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