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1.
Am J Hum Genet ; 109(8): 1549-1558, 2022 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-35858628

RESUMO

Deoxyhypusine hydroxylase (DOHH) is the enzyme catalyzing the second step in the post-translational synthesis of hypusine [Nε-(4-amino-2-hydroxybutyl)lysine] in the eukaryotic initiation factor 5A (eIF5A). Hypusine is formed exclusively in eIF5A by two sequential enzymatic steps catalyzed by deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). Hypusinated eIF5A is essential for translation and cell proliferation in eukaryotes, and all three genes encoding eIF5A, DHPS, and DOHH are highly conserved throughout eukaryotes. Pathogenic variants affecting either DHPS or EIF5A have been previously associated with neurodevelopmental disorders. Using trio exome sequencing, we identified rare bi-allelic pathogenic missense and truncating DOHH variants segregating with disease in five affected individuals from four unrelated families. The DOHH variants are associated with a neurodevelopmental phenotype that is similar to phenotypes caused by DHPS or EIF5A variants and includes global developmental delay, intellectual disability, facial dysmorphism, and microcephaly. A two-dimensional gel analyses revealed the accumulation of deoxyhypusine-containing eIF5A [eIF5A(Dhp)] and a reduction in the hypusinated eIF5A in fibroblasts derived from affected individuals, providing biochemical evidence for deficiency of DOHH activity in cells carrying the bi-allelic DOHH variants. Our data suggest that rare bi-allelic variants in DOHH result in reduced enzyme activity, limit the hypusination of eIF5A, and thereby lead to a neurodevelopmental disorder.


Assuntos
Lisina , Oxigenases de Função Mista , Transtornos do Neurodesenvolvimento , Alelos , Expressão Gênica , Humanos , Lisina/análogos & derivados , Oxigenases de Função Mista/genética , Transtornos do Neurodesenvolvimento/genética
2.
J Integr Neurosci ; 22(1): 14, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36722231

RESUMO

BACKGROUND: The pathogenesis of depression is complex, with the brain's reward system likely to play an important role. The nucleus accumbens (NAc) is a key region in the brain that integrates reward signals. Lipopolysaccharides (LPS) can induce depressive-like behaviors and enhance neuroplasticity in NAc, but the underlying mechanism is still unknown. We previously found that eukaryotic translation initiation factor A1 (eIF5A1) acts as a ribosome-binding protein to regulate protein translation and to promote neuroplasticity. METHODS: In the present study, LPS was administered intraperitoneally to rats and the expression and cellular location of eIF5A1 was then investigated by RT-PCR, Western blotting and immunofluorescence. Subsequently, a neuron-specific lentivirus was used to regulate eIF5A1 expression in vivo and in vitro. Neuroplasticity was then examined by Golgi staining and by measurement of neuronal processes. Finally, proteomic analysis was used to identify proteins regulated by eIF5A1. RESULTS: The results showed that eIF5A1 expression was significantly increased in the NAc neurons of LPS rats. Following the knockdown of eIF5A1 in NAc neurons, the LPS-induced increases in neuronal arbors and spine density were significantly attenuated. Depression-like behaviors were also reduced. Neurite outgrowth of NAc neurons in vitro also increased or decreased in parallel with the increase or decrease in eIF5A1 expression, respectively. The proteomic results showed that eIF5A1 regulates the expression of many neuroplasticity-related proteins in neurons. CONCLUSIONS: These results confirm that eIF5A1 is involved in LPS-induced depression-like behavior by increasing neuroplasticity in the NAc. Our study also suggests the brain's reward system may play an important role in the pathogenesis of depression.


Assuntos
Depressão , Núcleo Accumbens , Fatores de Iniciação de Peptídeos , Animais , Ratos , Depressão/induzido quimicamente , Lipopolissacarídeos , Plasticidade Neuronal , Proteômica , Fatores de Iniciação de Peptídeos/genética , Fator de Iniciação de Tradução Eucariótico 5A
3.
Int J Mol Sci ; 24(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37047039

RESUMO

The human eukaryotic translation initiation factor 5A (EIF5A) family consists of three members, namely EIF5A1, EIF5A2, and EIF5AL1. Recent studies have shown that the expression of EIF5As is related to many human diseases, such as diabetes, viral infection, central nervous system injury, and cancer. Among them, EIF5A1 plays different functions in various cancers, possibly as a tumor-suppressor or oncogene, while EIF5A2 promotes the occurrence and development of cancer. Yet, the biological function of EIF5AL1 is not being studied so far. Interestingly, although there are only three amino acid (at residues 36, 45, and 109) differences between EIF5A1 and EIF5AL1, we demonstrate that only EIF5A1 can be hypusinated while EIF5AL1 cannot, and EIF5AL1 has a tumor-suppressor-like function by inhibiting cell proliferation and migration. We also show that EIF5AL1 protein turnover is mediated through the proteasomal pathway, and EIF5AL1 protein turnover is much faster than that of EIF5A1, which may explain their differential protein expression level in cells. By engineering single and double mutations on these three amino acids, we pinpoint which of these amino acids are critical for hypusination and protein stability. The data of this work should fill in the gaps in EIF5As research and pave the way for future studies on EIF5AL1.


Assuntos
Lisina , Neoplasias , Humanos , Aminoácidos , Fatores de Iniciação em Eucariotos/genética , Fatores de Iniciação em Eucariotos/metabolismo , Lisina/metabolismo , Neoplasias/metabolismo , Fatores de Iniciação de Peptídeos/genética , Fatores de Iniciação de Peptídeos/metabolismo , Estabilidade Proteica , Fator de Iniciação de Tradução Eucariótico 5A
4.
Cancer Cell Int ; 20: 142, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368188

RESUMO

The eukaryotic translation initiation factor 5A1 (eIF5A1) and its homolog eIF5A2 are the only two human proteins containing the unique post-translational modification-hypusination, which is essential for the function of these two proteins. eIF5A1 was initially identified as a translation initiation factor by promoting the first peptide bond formation of protein during translation; however, recent results suggest that eIF5A1 also functions as a translation elongation factor. It has been shown that eIF5A1 is implicated in certain human diseases, including diabetes, several human cancer types, viral infections and diseases of neural system. Meanwhile, eIF5A2 is overexpressed in many cancers, and plays an important role in the development and progression of cancers. As multiple roles of these two factors were observed among these studies, therefore, it remains unclear whether they act as oncogene or tumor suppressor. In this review, the recent literature of eIF5As and their roles in human diseases, especially in human cancers, will be discussed.

5.
Biochem Biophys Res Commun ; 519(4): 838-845, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31558321

RESUMO

Metastasis is the leading cause of mortality in patients with solid tumors. In this regard, we previously reported that Pseudopodium-Enriched Atypical Kinase One (PEAK1) is necessary for non-canonical Transforming Growth Factor ß (TGFß) signaling and TGFß/fibronectin-induced metastasis. Here, we demonstrate that inhibition of DHPS-dependent eIF5A1/2 hypusination blocks PEAK1 and E-Cadherin expression, breast cancer cell viability and TGFß/fibronectin-induced PEAK1-dependent breast cancer metastasis. Interestingly, TGFß stimulation of high-grade metastatic breast cancer cells increases and sustains eIF5A1/2 hypusination. We used a suite of bioinformatics platforms to search biochemical/functional interactions and clinical databases for additional control points in eIF5A1/2 and PEAK1-Epithelial to Mesenchymal Transition (EPE) pathways. This effort revealed that interacting EPE genes were enriched for TP53 transcriptional targets and were commonly co-amplified in breast cancer patients harboring inactivating TP53 mutations. Taken together, these results suggest that combinatorial therapies targeting DHPS and protein activities elevated in TP53-mutant breast cancers may reduce systemic tumor burden and improve patient outcomes.


Assuntos
Neoplasias da Mama/metabolismo , Fibronectinas/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Proteína Supressora de Tumor p53/genética , Neoplasias da Mama/patologia , Caderinas/antagonistas & inibidores , Caderinas/genética , Caderinas/metabolismo , Feminino , Guanina/análogos & derivados , Guanina/farmacologia , Humanos , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Fatores de Iniciação de Peptídeos/antagonistas & inibidores , Prognóstico , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas de Ligação a RNA/antagonistas & inibidores , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/metabolismo , Fator de Iniciação de Tradução Eucariótico 5A
6.
Biochem Biophys Res Commun ; 445(1): 95-9, 2014 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-24491565

RESUMO

Cadmium (Cd) and Cd compounds are widely-distributed in the environment and well-known carcinogens. Here, we report that in CdCl2-exposed human bronchial epithelial cells (BEAS-2B), the level of p53 is dramatically decreased in a time- and dose-dependent manner, suggesting that the observed Cd-induced cytotoxicity is not likely due to the pro-apoptotic function of p53. Therefore, this prompted us to further study the responsive pro-apoptotic factors by proteomic approaches. Interestingly, we identified that high levels (20 or 30 µM) of Cd can significantly upregulate the protein levels of eukaryotic translation initiation factor 5A1 (eIF5A1) and redox-sensitive transcription factor NF-κB p65. Moreover, there is an enhanced NF-κB nuclear translocation as well as chromatin-binding in Cd-treated BEAS-2B cells. We also show that small interfering RNA-specific knockdown of eIF5A1 in Cd-exposed cells attenuated the Cd cytotoxicity, indicating the potential role of eIF5A1 in Cd cytotoxicity. As eIF5A1 is reported to be related with cell apoptosis but little is known about its transcriptional control, we hypothesize that NF-κB might likely modulate eIF5A1 gene expression. Notably, by bioinformatic analysis, several potential NF-κB binding sites on the upstream promoter region of eIF5A1 gene can be found. Subsequent chromatin immunoprecipitation assay revealed that indeed there is enhanced NF-κB binding on eIF5A1 promoter region of Cd-treated BEAS-2B cells. Taken together, our findings suggest for the first time a regulatory mechanism for the pro-apoptotic protein eIF5A1 in which its level is possibly modulated by NF-κB in human lung cells.


Assuntos
Cádmio/farmacologia , Células Epiteliais/efeitos dos fármacos , NF-kappa B/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Regulação para Cima/efeitos dos fármacos , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Western Blotting , Brônquios/citologia , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Cromatina/metabolismo , Relação Dose-Resposta a Droga , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Humanos , Fatores de Iniciação de Peptídeos/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Proteômica/métodos , Interferência de RNA , Proteínas de Ligação a RNA/genética , Proteína Supressora de Tumor p53/metabolismo , Fator de Iniciação de Tradução Eucariótico 5A
7.
Biol Open ; 12(3)2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36848144

RESUMO

The eukaryotic translation initiation factor 5A1 (eIF5A1) and 5A2 (eIF5A2) are important proteins in a variety of physiological and pathophysiological processes and their function has been linked to neurodevelopmental disorders, cancer, and viral infections. Here, we report two new genome-edited mouse models, generated using a CRISPR-Cas9 approach, in which the amino acid residue lysine 50 is replaced with arginine 50 (K50R) in eIF5A1 or in the closely related eIF5A2 protein. This mutation prevents the spermidine-dependent post-translational formation of hypusine, a unique lysine derivative that is necessary for activation of eIF5A1 and eIF5A2. Mouse brain lysates from homozygous eif5a2-K50R mutant mice (eif5a2K50R/K50R) confirmed the absence of hypusine formation of eIF5A2, and metabolomic analysis of primary mouse dermal fibroblasts revealed significant alterations in the metabolite landscape compared to controls including increased levels of tryptophan, kyrunenine, pyridoxine, nicotinamide adenine dinucleotide, riboflavin, flavin adenine dinucleotide, pantothenate, and coenzyme A. Further supported by new publicly available bioinformatics data, these new mouse models represent excellent in vivo models to study hypusine-dependent biological processes, hypusination-related disorders caused by eIF5A1 and eIF5A2 gene aberrations or mRNA expression dysregulation, as well as several major human cancer types and potential therapies.


Assuntos
Lisina , Neoplasias , Humanos , Animais , Camundongos , Lisina/metabolismo , Neoplasias/metabolismo , Expressão Gênica
8.
Front Cell Infect Microbiol ; 12: 960138, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35967877

RESUMO

Active hypusine-modified initiation elongation factor 5A is critical for cell proliferation and differentiation, embryonic development, and innate immune response of macrophages to bacterial infection. Here, we demonstrate that both virus infection and double-stranded RNA viral mimic stimulation induce the hypusination of eIF5A. Furthermore, we show that activation of eIF5A is essential for the replication of several RNA viruses including influenza A virus, vesicular stomatitis virus, chikungunya virus, mayaro virus, una virus, zika virus, and punta toro virus. Finally, our data reveal that inhibition of eIF5A hypusination using the spermidine analog GC7 or siRNA-mediated downmodulation of eIF5A1 induce upregulation of endoplasmic reticulum stress marker proteins and trigger the transcriptional induction of interferon and interferon-stimulated genes, mechanisms that may explain the broad-spectrum antiviral activity of eIF5A inhibition.


Assuntos
Vírus de RNA , Viroses , Infecção por Zika virus , Zika virus , Antivirais , Humanos , Interferons , RNA de Cadeia Dupla , Replicação Viral
9.
J Drug Target ; 30(6): 623-633, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35100927

RESUMO

Endometrial cancer (EC) is a common and deadly cancer in women and novel therapeutic approaches are urgently needed. Polyamines (putrescine, spermidine, spermine) are critical for mammalian cell proliferation and MYC coordinately regulates polyamine metabolism through ornithine decarboxylase (ODC). ODC is a MYC target gene and rate-limiting enzyme of polyamine biosynthesis and the FDA-approved anti-protozoan drug α-difluoromethylornithine (DFMO) inhibits ODC activity and induces polyamine depletion that leads to tumour growth arrest. Spermidine is required for the hypusine-dependent activation of eukaryotic translation initiation factors 5A1 (eIF5A1) and 5A2 (eIF5A2) and connects the MYC/ODC-induced deregulation of spermidine to eIF5A1/2 protein translation, which is increased during cancer cell proliferation. We show that eIF5A1 is significantly upregulated in EC cells compared to control cells (p=.000038) and that combined pharmacological targeting of ODC and eIF5A hypusination with cytostatic drugs DFMO and N1-guanyl-1,7-diaminoheptane (GC7), respectively, reduces eIF5A1 activation and synergistically induces apoptosis in EC cells. In vivo, DFMO/GC7 suppressed xenografted EC tumour growth in mice more potently than each drug alone compared to control (p=.002) and decreased putrescine (p=.045) and spermidine levels in tumour tissues. Our data suggest DFMO and GC7 combination therapy may be useful in the treatment or prevention of EC.


Assuntos
Neoplasias do Endométrio , Poliaminas , Animais , Eflornitina/farmacologia , Neoplasias do Endométrio/tratamento farmacológico , Feminino , Humanos , Lisina/análogos & derivados , Mamíferos/metabolismo , Camundongos , Ornitina Descarboxilase/metabolismo , Poliaminas/metabolismo , Putrescina/metabolismo , Espermidina/metabolismo , Espermidina/farmacologia , Espermina/metabolismo , Espermina/farmacologia
10.
Biomed Pharmacother ; 100: 168-175, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29428664

RESUMO

Epithelial ovarian cancer (EOC) is one of the most common gynecological cancers and has the highest mortality rate thereof. We found abundant eukaryotic translation initiation factor 5A1 (EIF5A1) in 54 EOC tissues, and high EIF5A1 levels predicted poor survival. EIF5A1 ectopic expression enhanced EOC cell proliferative, migration, and invasive capabilities, while EIF5A1 knockdown suppressed them. Most importantly, GC7 (N1-guanyl-1,7-diaminoheptane, an EIF5A1 hypusination inhibitor) could reverse the effect of EIF5A1 upregulation on EOC cell proliferation, migration, and invasion and mutant type EIF5A1K50A plasmid [bearing a single point mutation (K50 → A50) that prevents hypusination] had no effects on these malignant behaviors. Our findings imply that EIF5A1 is a vital regulator of EOC proliferation and progression and is a potential prognostic marker and therapeutic target in EOC.


Assuntos
Movimento Celular/genética , Proliferação de Células/genética , Células Epiteliais/patologia , Neoplasias Epiteliais e Glandulares/metabolismo , Neoplasias Ovarianas/metabolismo , Ovário/patologia , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Carcinoma Epitelial do Ovário , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Epiteliais/metabolismo , Feminino , Guanina/análogos & derivados , Guanina/farmacologia , Humanos , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Neoplasias Epiteliais e Glandulares/genética , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Ovário/metabolismo , Fatores de Iniciação de Peptídeos/antagonistas & inibidores , Fatores de Iniciação de Peptídeos/genética , Proteínas de Ligação a RNA/antagonistas & inibidores , Proteínas de Ligação a RNA/genética , Regulação para Cima , Fator de Iniciação de Tradução Eucariótico 5A
11.
J Proteomics ; 91: 188-99, 2013 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-23238062

RESUMO

It is well known that trauma is frequently accompanied by spontaneous functional recovery after spinal cord injury (SCI), but the underlying mechanisms remain elusive. In this study, BBB scores showed a gradual return of locomotor functions after SCT. Proteomics analysis revealed 16 differential protein spots in the gastrocnemius muscle between SCT and normal rats. Of these differential proteins, eukaryotic translation initiation factor 5A1 (elf-5A1), a highly conserved molecule throughout eukaryotes, exhibited marked upregulation in the gastrocnemius muscle after SCT. To study the role of eIF-5A1 in the restoration of hindlimb locomotor functions following SCT, we used siRNA to downregulate the mRNA level of eIF-5A1. Compared with untreated SCT control rats, those subjected to eIF-5A1 knockdown exhibited impaired functional recovery. Moreover, gene expression microarrays and bioinformatic analysis showed high correlation between three main signal pathways (ErbB, MAPK and neurotrophin signal pathways) and eIF-5A1. These signal pathways regulate cell proliferation, differentiation and neurocyte growth. Consequently, eIF-5A1 played a pivotal role via these signal pathways in hindlimb locomotor functional recovery after SCT, which could pave the way for the development of a new strategy for the treatment of spinal cord injury in clinical trials.


Assuntos
Membro Posterior/fisiologia , Músculos/metabolismo , Fatores de Crescimento Neural/metabolismo , Proteínas Oncogênicas v-erbB/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Traumatismos da Medula Espinal/fisiopatologia , Animais , Diferenciação Celular , Proliferação de Células , Biologia Computacional , Feminino , Perfilação da Expressão Gênica , Sistema de Sinalização das MAP Quinases , Movimento , Músculo Esquelético/metabolismo , Proteômica , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Transdução de Sinais , Regulação para Cima , Fator de Iniciação de Tradução Eucariótico 5A
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