RESUMO
As part of its pathogenesis, Salmonella enterica serovar Typhimurium delivers effector proteins into host cells. One effector is SspH2, a member of the so-called novel E3 ubiquitin ligase family, that interacts with and enhances, NOD1 pro-inflammatory signaling, though the underlying mechanisms are unclear. Here, we report that SspH2 interacts with multiple members of the NLRC family to enhance pro-inflammatory signaling by targeted ubiquitination. We show that SspH2 modulates host innate immunity by interacting with both NOD1 and NOD2 in mammalian epithelial cell culture via the NF-κB pathway. Moreover, purified SspH2 and NOD1 directly interact, where NOD1 potentiates SspH2 E3 ubiquitin ligase activity. Mass spectrometry and mutational analyses identified four key lysine residues in NOD1 that are required for its enhanced activation by SspH2, but not its basal activity. These critical lysine residues are positioned in the same region of NOD1 and define a surface on the receptor that appears to be targeted by SspH2. Overall, this work provides evidence for post-translational modification of NOD1 by ubiquitin and uncovers a unique mechanism of spatially selective ubiquitination to enhance the activation of an archetypal NLR.
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Cisplatin is an effective chemotherapeutic agent, yet its use is limited by several adverse drug reactions, known as cisplatin-induced toxicities (CITs). We recently demonstrated that cisplatin could elicit proinflammatory responses associated with CITs through Toll-like receptor 4 (TLR4). TLR4 is best recognized for binding bacterial lipopolysaccharide (LPS) via its coreceptor, MD-2. TLR4 is also proposed to directly bind transition metals, such as nickel. Little is known about the nature of the cisplatin-TLR4 interaction. Here, we show that soluble TLR4 was capable of blocking cisplatin-induced, but not LPS-induced, TLR4 activation. Cisplatin and nickel, but not LPS, were able to directly bind soluble TLR4 in a microscale thermophoresis binding assay. Interestingly, TLR4 histidine variants that abolish nickel binding reduced, but did not eliminate, cisplatin-induced TLR4 activation. This was corroborated by binding data that showed cisplatin, but not nickel, could directly bind mouse TLR4 that lacks these histidine residues. Altogether, our findings suggest that TLR4 can directly bind cisplatin in a manner that is enhanced by, but not dependent on, histidine residues that facilitate binding to transition metals. SIGNIFICANCE STATEMENT: This work describes how the xenobiotic cisplatin interacts with Toll-like receptor 4 (TLR4) to initiate proinflammatory signaling that underlies cisplatin toxicities, which are severe adverse outcomes in cisplatin treatment. Here, this study provides a mechanistic bridge between cisplatin extracellular interactions with TLR4 and previous observations that genetic and chemical inhibition of TLR4 mitigates cisplatin-induced toxicity.
Assuntos
Cisplatino , Receptor 4 Toll-Like , Animais , Camundongos , Alérgenos , Cisplatino/toxicidade , Histidina , Lipopolissacarídeos/farmacologia , Antígeno 96 de Linfócito/química , Antígeno 96 de Linfócito/genética , Antígeno 96 de Linfócito/metabolismo , Receptor 4 Toll-Like/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismoRESUMO
Toll-like receptor 4 (TLR4) recognizes bacterial lipopolysaccharide (LPS) and can also be activated by some Group 9/10 transition metals, which is believed to mediate immune hypersensitivity reactions. In this work, we test whether TLR4 can be activated by the Group 10 metal platinum and the platinum-based chemotherapeutic cisplatin. Cisplatin is invaluable in childhood cancer treatment but its use is limited due to a permanent hearing loss (cisplatin-induced ototoxicity, CIO) adverse effect. We demonstrate that platinum and cisplatin activate pathways downstream of TLR4 to a similar extent as the known TLR4 agonists LPS and nickel. We further show that TLR4 is required for cisplatin-induced inflammatory, oxidative, and cell death responses in hair cells in vitro and for hair cell damage in vivo. Finally, we identify a TLR4 small molecule inhibitor able to curtail cisplatin toxicity in vitro. Thus, our findings indicate that TLR4 is a promising therapeutic target to mitigate CIO.
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Antineoplásicos , Neoplasias , Ototoxicidade , Antineoplásicos/efeitos adversos , Cisplatino/toxicidade , Humanos , Neoplasias/tratamento farmacológico , Platina/uso terapêutico , Receptor 4 Toll-Like/genéticaRESUMO
Cisplatin is a platinum-based chemotherapeutic that has long since been effective against a variety of solid-cancers, substantially improving the five-year survival rates for cancer patients. Its use has also historically been limited by its adverse drug reactions, or cisplatin-induced toxicities (CITs). Of these reactions, cisplatin-induced nephrotoxicity (CIN), cisplatin-induced peripheral neuropathy (CIPN), and cisplatin-induced ototoxicity (CIO) are the three most common of several CITs recognised thus far. While the anti-cancer activity of cisplatin is well understood, the mechanisms driving its toxicities have only begun to be defined. Most of the literature pertains to damage caused by oxidative stress that occurs downstream of cisplatin treatment, but recent evidence suggests that the instigator of CIT development is inflammation. Cisplatin has been shown to induce pro-inflammatory signalling in CIN, CIPN, and CIO, all of which are associated with persisting markers of inflammation, particularly from the innate immune system. This review covered the hallmarks of inflammation common and distinct between different CITs, the role of innate immune components in development of CITs, as well as current treatments targeting pro-inflammatory signalling pathways to conserve the use of cisplatin in chemotherapy and improve long-term health outcomes of cancer patients.
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Antineoplásicos , Neoplasias , Doenças do Sistema Nervoso Periférico , Antineoplásicos/efeitos adversos , Cisplatino/farmacologia , Humanos , Inflamação/tratamento farmacológico , Neoplasias/induzido quimicamente , Neoplasias/tratamento farmacológico , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Transdução de SinaisRESUMO
BACKGROUND: Whole-exome sequencing has transformed gene discovery and diagnosis in rare diseases. Translation into disease-modifying treatments is challenging, particularly for intellectual developmental disorder. However, the exception is inborn errors of metabolism, since many of these disorders are responsive to therapy that targets pathophysiological features at the molecular or cellular level. METHODS: To uncover the genetic basis of potentially treatable inborn errors of metabolism, we combined deep clinical phenotyping (the comprehensive characterization of the discrete components of a patient's clinical and biochemical phenotype) with whole-exome sequencing analysis through a semiautomated bioinformatics pipeline in consecutively enrolled patients with intellectual developmental disorder and unexplained metabolic phenotypes. RESULTS: We performed whole-exome sequencing on samples obtained from 47 probands. Of these patients, 6 were excluded, including 1 who withdrew from the study. The remaining 41 probands had been born to predominantly nonconsanguineous parents of European descent. In 37 probands, we identified variants in 2 genes newly implicated in disease, 9 candidate genes, 22 known genes with newly identified phenotypes, and 9 genes with expected phenotypes; in most of the genes, the variants were classified as either pathogenic or probably pathogenic. Complex phenotypes of patients in five families were explained by coexisting monogenic conditions. We obtained a diagnosis in 28 of 41 probands (68%) who were evaluated. A test of a targeted intervention was performed in 18 patients (44%). CONCLUSIONS: Deep phenotyping and whole-exome sequencing in 41 probands with intellectual developmental disorder and unexplained metabolic abnormalities led to a diagnosis in 68%, the identification of 11 candidate genes newly implicated in neurometabolic disease, and a change in treatment beyond genetic counseling in 44%. (Funded by BC Children's Hospital Foundation and others.).
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Exoma , Testes Genéticos/métodos , Erros Inatos do Metabolismo/genética , Análise de Sequência de DNA/métodos , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Genótipo , Humanos , Lactente , Deficiência Intelectual/genética , Masculino , Erros Inatos do Metabolismo/diagnóstico , Fenótipo , Adulto JovemRESUMO
BACKGROUND: Anthracyclines are a class of highly effective chemotherapeutic drugs commonly used to treat cancer patients. Anthracyclines, however, are associated with the development of serious adverse reactions, including anthracycline-induced cardiotoxicity (ACT). It is not possible, within current practice, to accurately individualize treatment to minimize risk. PROCEDURE: Recently, genetic variants have been associated with the risk of ACT in children. Building on these findings and the related genetic test, a predictive model was developed which classifies pediatric patients by their risk of developing ACT. We assessed the value of this ACT-predictive risk classification in addressing ACT. RESULTS: With current care, the estimated average lifetime cost of ACT is $8,667 per anthracycline-treated patient and approximately 7% of patients are expected to die from ACT. The projected impact of the information from the new predictive model is a 17% reduction in the risk of mortality from ACT and savings of about 6%: lives saved and lower costs. CONCLUSION: The newly identified genetic variants associated with the risk of ACT provide information that allows a more reliable prediction of the risk of ACT for a given patient and can be obtained at a very moderate cost, which is expected to lead to meaningful progress in reducing harm and costs associated with ACT.
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Antraciclinas/efeitos adversos , Cardiotoxicidade , Neoplasias/tratamento farmacológico , Testes Farmacogenômicos/economia , Testes Farmacogenômicos/métodos , Antineoplásicos/efeitos adversos , Criança , Análise Custo-Benefício , Árvores de Decisões , Feminino , Custos de Cuidados de Saúde , Humanos , MasculinoRESUMO
Four children in three unrelated families (one consanguineous) presented with lethargy, hyperlactatemia, and hyperammonemia of unexplained origin during the neonatal period and early childhood. We identified and validated three different CA5A alterations, including a homozygous missense mutation (c.697T>C) in two siblings, a homozygous splice site mutation (c.555G>A) leading to skipping of exon 4, and a homozygous 4 kb deletion of exon 6. The deleterious nature of the homozygous mutation c.697T>C (p.Ser233Pro) was demonstrated by reduced enzymatic activity and increased temperature sensitivity. Carbonic anhydrase VA (CA-VA) was absent in liver in the child with the homozygous exon 6 deletion. The metabolite profiles in the affected individuals fit CA-VA deficiency, showing evidence of impaired provision of bicarbonate to the four enzymes that participate in key pathways in intermediary metabolism: carbamoylphosphate synthetase 1 (urea cycle), pyruvate carboxylase (anaplerosis, gluconeogenesis), propionyl-CoA carboxylase, and 3-methylcrotonyl-CoA carboxylase (branched chain amino acids catabolism). In the three children who were administered carglumic acid, hyperammonemia resolved. CA-VA deficiency should therefore be added to urea cycle defects, organic acidurias, and pyruvate carboxylase deficiency as a treatable condition in the differential diagnosis of hyperammonemia in the neonate and young child.
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Anidrase Carbônica V/deficiência , Anidrase Carbônica V/genética , Hiperamonemia/genética , Adolescente , Sequência de Bases , Criança , Pré-Escolar , Éxons , Feminino , Deleção de Genes , Variação Genética , Homozigoto , Humanos , Hiperamonemia/terapia , Lactente , Fígado/enzimologia , Masculino , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Linhagem , Análise de Sequência de DNA , TemperaturaRESUMO
AIMS: Anthracycline-induced cardiotoxicity (ACT) occurs in 57% of treated patients and remains an important limitation of anthracycline-based chemotherapy. In various genetic association studies, potential genetic risk markers for ACT have been identified. Therefore, we developed evidence-based clinical practice recommendations for pharmacogenomic testing to further individualize therapy based on ACT risk. METHODS: We followed a standard guideline development process, including a systematic literature search, evidence synthesis and critical appraisal, and the development of clinical practice recommendations with an international expert group. RESULTS: RARG rs2229774, SLC28A3 rs7853758 and UGT1A6 rs17863783 variants currently have the strongest and the most consistent evidence for association with ACT. Genetic variants in ABCC1, ABCC2, ABCC5, ABCB1, ABCB4, CBR3, RAC2, NCF4, CYBA, GSTP1, CAT, SULT2B1, POR, HAS3, SLC22A7, SCL22A17, HFE and NOS3 have also been associated with ACT, but require additional validation. We recommend pharmacogenomic testing for the RARG rs2229774 (S427L), SLC28A3 rs7853758 (L461L) and UGT1A6*4 rs17863783 (V209V) variants in childhood cancer patients with an indication for doxorubicin or daunorubicin therapy (Level B - moderate). Based on an overall risk stratification, taking into account genetic and clinical risk factors, we recommend a number of management options including increased frequency of echocardiogram monitoring, follow-up, as well as therapeutic options within the current standard of clinical practice. CONCLUSIONS: Existing evidence demonstrates that genetic factors have the potential to improve the discrimination between individuals at higher and lower risk of ACT. Genetic testing may therefore support both patient care decisions and evidence development for an improved prevention of ACT.
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Antraciclinas/efeitos adversos , Cardiotoxicidade/prevenção & controle , Testes Genéticos , Medicina Baseada em Evidências , Predisposição Genética para Doença/genética , Humanos , Proteína 2 Associada à Farmacorresistência Múltipla , Fatores de RiscoRESUMO
Currently no pharmacogenomics-based criteria exist to guide clinicians in identifying individuals who are at risk of hearing loss from cisplatin-based chemotherapy. This review summarizes findings from pharmacogenomic studies that report genetic polymorphisms associated with cisplatin-induced hearing loss and aims to (1) provide up-to-date information on new developments in the field, (2) provide recommendations for the use of pharmacogenetic testing in the prevention, assessment, and management of cisplatin-induced hearing loss in children and adults, and (3) identify knowledge gaps to direct and prioritize future research. These practice recommendations for pharmacogenetic testing in the context of cisplatin-induced hearing loss reflect a review and evaluation of recent literature, and are designed to assist clinicians in providing optimal clinical care for patients receiving cisplatin-based chemotherapy.
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Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Cisplatino/efeitos adversos , Cisplatino/uso terapêutico , Marcadores Genéticos/genética , Perda Auditiva/induzido quimicamente , Perda Auditiva/genética , Humanos , Farmacogenética/métodos , Polimorfismo Genético/genéticaRESUMO
To further its pathogenesis, S. Typhimurium delivers effector proteins into host cells, including the novel E3 ubiquitin ligase (NEL) effector SspH2. Using model systems in a cross-kingdom approach we gained further insight into the molecular function of this effector. Here, we show that SspH2 modulates innate immunity in both mammalian and plant cells. In mammalian cell culture, SspH2 significantly enhanced Nod1-mediated IL-8 secretion when transiently expressed or bacterially delivered. In addition, SspH2 also enhanced an Rx-dependent hypersensitive response in planta. In both of these nucleotide-binding leucine rich repeat receptor (NLR) model systems, SspH2-mediated phenotypes required its catalytic E3 ubiquitin ligase activity and interaction with the conserved host protein SGT1. SGT1 has an essential cell cycle function and an additional function as an NLR co-chaperone in animal and plant cells. Interaction between SspH2 and SGT1 was restricted to SGT1 proteins that have NLR co-chaperone function and accordingly, SspH2 did not affect SGT1 cell cycle functions. Mechanistic studies revealed that SspH2 interacted with, and ubiquitinated Nod1 and could induce Nod1 activity in an agonist-independent manner if catalytically active. Interestingly, SspH2 in vitro ubiquitination activity and protein stability were enhanced by SGT1. Overall, this work adds to our understanding of the sophisticated mechanisms used by bacterial effectors to co-opt host pathways by demonstrating that SspH2 can subvert immune responses by selectively exploiting the functions of a conserved host co-chaperone.
Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Imunidade Inata , Proteínas de Membrana/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Adaptadoras de Sinalização NOD/metabolismo , Salmonella typhimurium/imunologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Ciclo Celular/química , Linhagem Celular , Deleção de Genes , Interações Hospedeiro-Patógeno , Humanos , Interleucina-8/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas Mutantes/metabolismo , Imunidade Vegetal , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estabilidade Proteica , Proteínas Recombinantes/metabolismo , Salmonella typhimurium/metabolismo , Nicotiana/genética , Nicotiana/imunologia , Nicotiana/metabolismo , Nicotiana/microbiologia , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , Regulação para CimaRESUMO
During the late stages of infection, Salmonella secretes numerous effectors through a type III secretion system that is encoded within Salmonella pathogenicity island 2 (SPI2). Despite the importance of SPI2 as a major virulence factor leading to the systemic spread of the bacteria and diseases, a global view of its effects on host responses is still lacking. Here, we measured global impacts of SPI2 effectors on the host phosphorylation and protein expression levels in RAW264.7 and in HeLa cells, as macrophage and nonphagocytic models of infection. We observe that SPI2 effectors differentially modulate the host phosphoproteome and cellular processes (e.g. protein trafficking, cytoskeletal regulation, and immune signaling) in a host cell-dependent manner. Our unbiased approach reveals the involvement of many previously unrecognized proteins, including E3 ligases (HERC4, RanBP2, and RAD18), kinases (CDK, SIK3, and WNK1), and histones (H2B1F, H4, and H15), in late stages of Salmonella infection. Furthermore, from this phosphoproteome analysis and other quantitative screens, we identified HSP27 as a direct in vitro and in vivo molecular target of the only type III secreted kinase, SteC. Using biochemical and cell biological assays, we demonstrate that SteC phosphorylates multiple sites in HSP27 and induces actin rearrangement through this protein. Together, these results provide a broader landscape of host players contributing to specific processes/pathways mediated by SPI2 effectors than was previously appreciated.
Assuntos
Proteínas de Bactérias/genética , Ilhas Genômicas , Proteínas de Choque Térmico HSP27/genética , Macrófagos/metabolismo , Fosfoproteínas/genética , Proteínas Quinases/genética , Proteoma/genética , Salmonella typhimurium/genética , Salmonella typhimurium/patogenicidade , Actinas/genética , Actinas/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Linhagem Celular , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP27/metabolismo , Células HeLa , Proteínas de Choque Térmico , Interações Hospedeiro-Patógeno , Humanos , Macrófagos/citologia , Macrófagos/microbiologia , Camundongos , Chaperonas Moleculares , Fosfoproteínas/metabolismo , Mapeamento de Interação de Proteínas , Proteínas Quinases/metabolismo , Proteoma/isolamento & purificação , Proteoma/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Bacterial pathogens operate by attacking crucial intracellular pathways in their hosts. These pathogens usually target more than one intracellular pathway and often interact at several points in each of these pathways to commandeer them fully. Although different bacterial pathogens tend to exploit similar pathway components in the host, the way in which they 'hijack' host cells usually differs. Knowledge of how pathogens target distinct cytoskeletal components and immune-cell signalling pathways is rapidly advancing, together with the understanding of bacterial virulence at a molecular level. Studying how these bacterial pathogens subvert host-cell pathways is central to understanding infectious disease.
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Bactérias/patogenicidade , Infecções Bacterianas/microbiologia , Infecções Bacterianas/patologia , Interações Hospedeiro-Patógeno , Animais , Apresentação de Antígeno , Citoesqueleto/metabolismo , Humanos , Transdução de SinaisRESUMO
Gram-negative bacterial pathogens have developed specialized secretion systems to transfer bacterial proteins directly into host cells. These bacterial effectors are central to virulence and reprogram host cell processes to favor bacterial survival, colonization, and proliferation. Knowing the complete set of effectors encoded by a particular pathogen is the key to understanding bacterial disease. In addition, the identification of the molecular assemblies that these effectors engage once inside the host cell is critical to determining the mechanism of action of each effector. In this work we used stable isotope labeling of amino acids in cell culture (SILAC), a powerful quantitative proteomics technique, to identify the proteins secreted by the Salmonella pathogenicity island-2 type three secretion system (SPI-2 T3SS) and to characterize the host interaction partners of SPI-2 effectors. We confirmed many of the known SPI-2 effectors and were able to identify several novel substrate candidates of this secretion system. We verified previously published host protein-effector binding pairs and obtained 11 novel interactions, three of which were investigated further and confirmed by reciprocal co-immunoprecipitation. The host cell interaction partners identified here suggest that Salmonella SPI-2 effectors target, in a concerted fashion, cellular processes such as cell attachment and cell cycle control that are underappreciated in the context of infection. The technology outlined in this study is specific and sensitive and serves as a robust tool for the identification of effectors and their host targets that is readily amenable to the study of other bacterial pathogens.
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Proteínas de Bactérias/metabolismo , Sistemas de Secreção Bacterianos/fisiologia , Ilhas Genômicas/fisiologia , Interações Hospedeiro-Patógeno/fisiologia , Proteínas de Membrana/metabolismo , Salmonella typhimurium/fisiologia , Salmonella typhimurium/patogenicidade , Proteínas de Bactérias/genética , Humanos , Proteínas de Membrana/genéticaRESUMO
Enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC respectively) are attaching and effacing bacterial pathogens that cause devastating diarrhoeal disease worldwide. These pathogens depend on a type III secretion system, which functions as a molecular syringe to translocate bacterial effector proteins directly into infected host cells. One of these effectors, NleC, was recently described as a zinc metalloprotease that targets NF-κB Rel-A (p65) and thus contributes to dampening of inflammatory signalling during EPEC and EHEC infection. We have identified the acetyltransferase p300 as an additional target of NleC. Several biochemical techniques were employed to demonstrate specific binding of p300 by NleC. We also show that NleC causes decreased abundance of p300 in cellular nuclei and that the metalloprotease domain of NleC is responsible for this phenotype. Furthermore, we demonstrate that overexpression of p300 can antagonize repression of IL-8 secretion by EPEC and that siRNA knock-down of p300 dampens IL-8 secretion by EPEC ΔnleC-infected cells. We have therefore identified a second target of NleC and provided the first example of a bacterial virulence factor targeting the acetyltransferase p300.
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Proteínas de Escherichia coli/metabolismo , Escherichia coli/enzimologia , Escherichia coli/patogenicidade , Interações Hospedeiro-Patógeno , Fatores de Virulência/metabolismo , Fatores de Transcrição de p300-CBP/metabolismo , Linhagem Celular , Humanos , Ligação Proteica , ProteóliseRESUMO
The effectiveness of anthracycline chemotherapeutics (e.g., doxorubicin) is limited by anthracycline-induced cardiotoxicity (ACT). A nonsynonymous variant (S427L) in the retinoic acid receptor-γ (RARG) gene has been associated with ACT. This variant causes reduced RARG activity, which is hypothesized to lead to increased susceptibility to ACT through reduced activation of the retinoic acid pathway. This study explored the effects of activating the retinoic acid pathway using a RAR-agonist, all-trans retinoic acid (ATRA), in human cardiomyocytes and mice treated with doxorubicin. In human cardiomyocytes, ATRA induced the gene expression of RARs (RARG, RARB) and repressed the expression of topoisomerase II enzyme genes (TOP2A, TOP2B), which encode for the molecular targets of anthracyclines and repressed downstream ACT response genes. Importantly, ATRA enhanced cell survival of human cardiomyocytes exposed to doxorubicin. The protective effect of ATRA was also observed in a mouse model (B6C3F1/J) of ACT, in which ATRA treatment improved heart function compared to doxorubicin-only treated mice. Histological analyses of the heart also indicated that ATRA treatment reduced the pathology associated with ACT. These findings provide additional evidence for the retinoic acid pathway's role in ACT and suggest that the RAR activator ATRA can modulate this pathway to reduce ACT.
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Antraciclinas , Cardiotoxicidade , Animais , Humanos , Camundongos , Antraciclinas/toxicidade , Antibióticos Antineoplásicos/farmacologia , Cardiotoxicidade/genética , Cardiotoxicidade/prevenção & controle , Cardiotoxicidade/metabolismo , DNA Topoisomerases Tipo II/genética , DNA Topoisomerases Tipo II/metabolismo , Doxorrubicina/toxicidade , Doxorrubicina/metabolismo , Miócitos Cardíacos/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Inibidores da Topoisomerase II/farmacologia , Tretinoína/farmacologia , Tretinoína/metabolismo , Receptor gama de Ácido RetinoicoRESUMO
Anthracyclines are highly effective chemotherapeutic agents; however, their clinical utility is limited by severe anthracycline-induced cardiotoxicity (ACT). Genome-wide association studies (GWAS) have uncovered several genetic variants associated with ACT, but the impact of these findings requires further elucidation. We conducted a transcriptome-wide association study (TWAS) using our previous GWAS summary statistics (n = 280 patients) to identify gene expression-related associations with ACT. We identified a genetic association between decreased expression of GDF5 and ACT (Z-score = -4.30, P = 1.70 × 10-5), which was replicated in an independent cohort (n = 845 patients, P = 3.54 × 10-3). Additionally, cell viability of GDF5-silenced human cardiac myocytes was significantly decreased in response to anthracycline treatment. Subsequent gene set enrichment and pathway analyses of the TWAS data revealed that genes essential for survival, cardioprotection and response to anthracyclines, as well as genes involved in ribosomal, spliceosomal and cardiomyopathy pathways are important for the development of ACT.
RESUMO
Cisplatin is a highly effective chemotherapeutic. Unfortunately, its use is limited by cisplatin-induced ototoxicity (CIO). Substantial research has been performed to uncover the genetic variants associated with CIO; however, there has been a lack of consistency in the results that have been reported. This paper aims to provide an overview of the current state of CIO genomics research, delving into the shortcomings of past research, and providing recommendations for future avenues of study.
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Cisplatino/farmacologia , Ototoxicidade , Farmacogenética , Antineoplásicos/farmacologia , Humanos , Ototoxicidade/etiologia , Ototoxicidade/genéticaRESUMO
Multiple sclerosis (MS) is a disease of the central nervous system treated with disease-modifying therapies, including the biologic, interferon-ß (IFN-ß). Up to 60% of IFN-ß-exposed MS patients develop abnormal biochemical liver test results1,2, and 1 in 50 experiences drug-induced liver injury3. Since genomic variation contributes to other forms of drug-induced liver injury4,5, we aimed to identify biomarkers of IFN-ß-induced liver injury using a two-stage genome-wide association study. The rs2205986 variant, previously linked to differential expression of IRF6, surpassed genome-wide significance in the combined two-stage analysis (P = 2.3 × 10-8, odds ratio = 8.3, 95% confidence interval = 3.6-19.2). Analysis of an independent cohort of IFN-ß-treated MS patients identified via electronic medical records showed that rs2205986 was also associated with increased peak levels of aspartate aminotransferase (P = 7.6 × 10-5) and alkaline phosphatase (P = 4.9 × 10-4). We show that these findings may be applicable to predicting IFN-ß-induced liver injury, offering insight into its safer use.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/genética , Variação Genética/genética , Fatores Reguladores de Interferon/genética , Interferon beta/genética , Esclerose Múltipla/genética , Feminino , Estudo de Associação Genômica Ampla/métodos , Humanos , MasculinoRESUMO
Cisplatin is a highly-effective and widely-used chemotherapeutic agent that causes ototoxicity in many patients. Pharmacogenomic studies of key genes controlling drug biotransformation identified variants in thiopurine methyltransferase (TPMT) as predictors of cisplatin-induced ototoxicity, although the mechanistic basis of this interaction has not been reported. Expression constructs of TPMT*3A, *3B and *3C variants were generated and monitored in cultured cells. Cellular TPMT*3A levels were detected at >20-fold lower amounts than the wild type confirming the unstable nature of this variant. The expression of wild type TPMT (TPMT*1) in two murine ear cell lines, HEI-OC1 and UB/OC-1, significantly mitigated their susceptibility to cisplatin toxicity. Cisplatin treatment induced Tlr4 gene expression in HEI-OC1 cells and this response was blunted by the expression of wild type TPMT but not TPMT*3A. In line with the significant mitigation of TPMT*1-expressing cells to cisplatin cytotoxicity, these findings demonstrate a drug-gene interaction between increased TPMT activity and decreased susceptibility to cisplatin-induced toxicity of inner ear cells.