RESUMO
The emergence of highly infectious pathogens with their potential for triggering global pandemics necessitate the development of effective treatment strategies, including broad-spectrum antiviral therapies to safeguard human health. This study investigates the antiviral activity of emetine, dehydroemetine (DHE), and congeneric compounds against SARS-CoV-2 and HCoV-OC43, and evaluates their impact on the host cell. Concurrently, we assess the potential cardiotoxicity of these ipecac alkaloids. Significantly, our data reveal that emetine and the (-)-R,S isomer of 2,3-dehydroemetine (designated in this paper as DHE4) reduce viral growth at nanomolar concentrations (i.e., IC50 â¼ 50-100 nM), paralleling those required for inhibition of protein synthesis, while calcium channel blocking activity occurs at elevated concentrations (i.e., IC50 â¼ 40-60 µM). Our findings suggest that the antiviral mechanisms primarily involve disruption of host cell protein synthesis and is demonstrably stereoisomer specific. The prospect of a therapeutic window in which emetine or DHE4 inhibit viral propagation without cardiotoxicity renders these alkaloids viable candidates in strategies worthy of clinical investigation.
Assuntos
Alcaloides , Emetina , Emetina/análogos & derivados , Humanos , Emetina/farmacologia , Ipeca/farmacologia , Cardiotoxicidade , Antivirais/toxicidadeRESUMO
PURPOSE: The high incidence of upper urinary tract urothelial carcinoma (UTUC) in Taiwan is largely due to exposure to aristolochic acid (AA), a principal component of Aristolochia-based herbal medicines. Here we systematically review the molecular epidemiology, clinical presentation and biomarkers associated with AA-induced UTUC. METHODS: This is a narrative review. Medline, Embase, and Web of Science were searched from inception to December 31, 2021. Studies evaluating the association, detection, and clinical characteristics of AA and UTUC were included. RESULTS: A nationwide database revealed 39% of the Taiwanese population had been exposed to AA-containing herbs between 1997 and 2003. Epidemiological reports revealed AA posed a significantly higher hazard for renal failure and UTUC in herbalists and the general population who ingested AA-containing herbs. The presence of aristolactam-DNA adducts and a distinctive signature mutation, A:T to T:A transversions, located predominantly on the non-transcribed DNA strand, with a strong preference for deoxyadenosine in a consensus sequence (CAG), was observed in many UTUC patients. Clinically, AA-related UTUC patients were characterized by a younger age, female gender, impaired renal function and recurrence of contralateral UTUC. To date, there are no preventive measures, except prophylactic nephrectomy, for subjects at risk of AA nephropathy or AA-related UTUC. CONCLUSION: AA exposure via Aristolochia-based herbal medicines is a problem throughout Taiwan, resulting in a high incidence of UTUC. Aristolactam-DNA adducts and a distinctive signature mutation, A:T to T:A transversions, can be used as biomarkers to identify AA-related UTUC. AA-related UTUC is associated with a high recurrence rate of contralateral UTUC.
Assuntos
Ácidos Aristolóquicos , Carcinoma de Células de Transição , Medicamentos de Ervas Chinesas , Neoplasias Renais , Neoplasias Ureterais , Neoplasias da Bexiga Urinária , Sistema Urinário , Humanos , Feminino , Carcinoma de Células de Transição/induzido quimicamente , Carcinoma de Células de Transição/epidemiologia , Carcinoma de Células de Transição/genética , Adutos de DNA/efeitos adversos , Medicamentos de Ervas Chinesas/efeitos adversos , Taiwan/epidemiologia , Carcinógenos , Neoplasias Renais/induzido quimicamente , Neoplasias Renais/epidemiologia , Neoplasias Renais/genética , Ácidos Aristolóquicos/efeitos adversos , Ácidos Aristolóquicos/análise , Neoplasias Ureterais/induzido quimicamente , Neoplasias Ureterais/epidemiologiaRESUMO
Recurrent upper tract urothelial carcinomas (UTUCs) arise in the context of nephropathy linked to exposure to the herbal carcinogen aristolochic acid (AA). Here we delineated the molecular programs underlying UTUC tumorigenesis in patients from endemic aristolochic acid nephropathy (AAN) regions in Southern Europe. We applied an integrative multiomics analysis of UTUCs, corresponding unaffected tissues and of patient urines. Quantitative microRNA (miRNA) and messenger ribonucleic acid (mRNA) expression profiling, immunohistochemical analysis by tissue microarrays and exome and transcriptome sequencing were performed in UTUC and nontumor tissues. Urinary miRNAs of cases undergoing surgery were profiled before and after tumor resection. Ribonucleic acid (RNA) and protein levels were analyzed using appropriate statistical tests and trend assessment. Dedicated bioinformatic tools were used for analysis of pathways, mutational signatures and result visualization. The results delineate UTUC-specific miRNA:mRNA networks comprising 89 miRNAs associated with 1,862 target mRNAs, involving deregulation of cell cycle, deoxyribonucleic acid (DNA) damage response, DNA repair, bladder cancer, oncogenes, tumor suppressors, chromatin structure regulators and developmental signaling pathways. Key UTUC-specific transcripts were confirmed at the protein level. Exome and transcriptome sequencing of UTUCs revealed AA-specific mutational signature SBS22, with 68% to 76% AA-specific, deleterious mutations propagated at the transcript level, a possible basis for neoantigen formation and immunotherapy targeting. We next identified a signature of UTUC-specific miRNAs consistently more abundant in the patients' urine prior to tumor resection, thereby defining biomarkers of tumor presence. The complex gene regulation programs of AAN-associated UTUC tumors involve regulatory miRNAs prospectively applicable to noninvasive urine-based screening of AAN patients for cancer presence and recurrence.
Assuntos
Ácidos Aristolóquicos/efeitos adversos , Biomarcadores Tumorais/genética , Carcinoma de Células de Transição/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , MicroRNAs/urina , Mutação , Neoplasias da Bexiga Urinária/patologia , Biomarcadores Tumorais/urina , Carcinoma de Células de Transição/induzido quimicamente , Carcinoma de Células de Transição/genética , Carcinoma de Células de Transição/urina , Exoma , Seguimentos , Humanos , Prognóstico , Proteoma/análise , Proteoma/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Neoplasias da Bexiga Urinária/induzido quimicamente , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/urinaRESUMO
Loss of fatty acid ß-oxidation (FAO) in the proximal tubule is a critical mediator of acute kidney injury and eventual fibrosis. However, transcriptional mediators of FAO in proximal tubule injury remain understudied. Krüppel-like factor 15 (KLF15), a highly enriched zinc-finger transcription factor in the proximal tubule, was significantly reduced in proximal tubule cells after aristolochic acid I (AAI) treatment, a proximal tubule-specific injury model. Proximal tubule specific knockout of Klf15 exacerbated proximal tubule injury and kidney function decline compared to control mice during the active phase of AAI treatment, and after ischemia-reperfusion injury. Furthermore, along with worsening proximal tubule injury and kidney function decline, knockout mice exhibited increased kidney fibrosis as compared to control mice during the remodeling phase after AAI treatment. RNA-sequencing of kidney cortex demonstrated increased transcripts involved in immune system and integrin signaling pathways and decreased transcripts encompassing metabolic pathways, specifically FAO, and PPARα signaling, in knockout versus control mice after AAI treatment. In silico and experimental chromatin immunoprecipitation studies collectively demonstrated that KLF15 occupied the promoter region of key FAO genes, CPT1A and ACAA2, in close proximity to transcription factor PPARα binding sites. While the loss of Klf15 reduced the expression of Cpt1a and Acaa2 and led to compromised FAO, induction of KLF15 partially rescued loss of FAO in AAI-treated cells. Klf15, Ppara, Cpt1a, and Acaa2 expression was also decreased in other mouse kidney injury models. Tubulointerstitial KLF15 independently correlated with eGFR, PPARA and CPT1A appearance in expression arrays from human kidney biopsies. Thus, proximal tubule-specific loss of Klf15 exacerbates acute kidney injury and fibrosis, likely due to loss of interaction with PPARα leading to loss of FAO gene transcription.
Assuntos
Injúria Renal Aguda , Ácidos Graxos/metabolismo , Fatores de Transcrição Kruppel-Like , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/genética , Animais , Rim , Túbulos Renais Proximais , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos KnockoutRESUMO
BACKGROUND: Aristolochic acids (AA) and arsenic are chemical carcinogens associated with urothelial carcinogenesis. Here we investigate the combined effects of AA and arsenic toward the risk of developing upper tract urothelial carcinoma (UTUC). METHODS: Hospital-based (n = 89) and population-based (2,921 cases and 11,684 controls) Taiwanese UTUC cohorts were used to investigate the association between exposure to AA and/or arsenic and the risk of developing UTUC. In the hospital cohort, AA exposure was evaluated by measuring aristolactam-DNA adducts in the renal cortex and by identifying A>T TP53 mutations in tumors. In the population cohort, AA exposure was determined from prescription health insurance records. Arsenic levels were graded from 0 to 3 based on concentrations in well water and the presence of arseniasis-related diseases. RESULTS: In the hospital cohort, 43, 26, and 20 patients resided in grade 0, 1+2, and 3 arseniasis-endemic areas, respectively. Aristolactam-DNA adducts were present in >90% of these patients, indicating widespread AA exposure. A>T mutations in TP53 were detected in 28%, 44%, and 22% of patients residing in grade 0, 1+2, and 3 arseniasis-endemic areas, respectively. Population studies revealed that individuals who consumed more AA-containing herbs had a higher risk of developing UTUC in both arseniasis-endemic and nonendemic areas. Logistic regression showed an additive effect of AA and arsenic exposure on the risk of developing UTUC. CONCLUSIONS: Exposure to both AA and arsenic acts additively to increase the UTUC risk in Taiwan. IMPACT: This is the first study to investigate the combined effect of AA and arsenic exposure on UTUC.
Assuntos
Ácidos Aristolóquicos/toxicidade , Arsênio/toxicidade , Carcinoma de Células de Transição/induzido quimicamente , Neoplasias da Bexiga Urinária/induzido quimicamente , Idoso , Carcinoma de Células de Transição/epidemiologia , Carcinoma de Células de Transição/genética , Carcinoma de Células de Transição/patologia , Estudos de Casos e Controles , Adutos de DNA , Feminino , Humanos , Incidência , Masculino , Gradação de Tumores , Taiwan/epidemiologia , Neoplasias da Bexiga Urinária/epidemiologia , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/patologiaRESUMO
The effect of variations in the expression of cytochrome P450 reductase (CPR or POR) is determined in mice with decreased POR expression to identify potential vulnerabilities in people with low POR expression. There is an age-dependent appearance of increasing vacuolization in the proximal tubules of the renal cortex in 4- to 9-month-old male (but not female) Cpr-low (CL) mice. These mice have low POR expression in all cells of the body and upregulation of lysosome-associated membrane protein 1 expression in the renal cortex. Vacuolization is also seen in extrahepatic CL and extrarenal CL male mice, but not in mice with tissue-specific Por deletion in liver, intestinal epithelium, or kidney. The occurrence of vacuolization is accompanied by increases in serum blood-urea-nitrogen levels. Male CL mice are hypersensitive to cisplatin- and gentamicin-induced renal toxicity at 3 months of age, before proximal tubular (PT) vacuoles are detectable. At doses that do not cause renal toxicity in wild-type mice, both drugs cause substantial increases in serum blood-urea-nitrogen levels and PT vacuolization in male but not female CL mice. The hypersensitivity to drug-induced renal toxicity is accompanied by increases in circulating drug levels. These novel findings demonstrate deficiency of renal function in mice with globally reduced POR expression and suggest that low POR expression may be a risk factor for drug-induced nephrotoxicity in humans.
Assuntos
Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/patologia , NADPH-Ferri-Hemoproteína Redutase/metabolismo , Insuficiência Renal/induzido quimicamente , Animais , Nitrogênio da Ureia Sanguínea , Cisplatino/farmacocinética , Creatinina/sangue , Gentamicinas/farmacocinética , Túbulos Renais Proximais/efeitos dos fármacos , Lisossomos/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Vacúolos/patologia , Vacúolos/ultraestruturaRESUMO
Current non-invasive approaches for detection of urothelial cancers are suboptimal. We developed a test to detect urothelial neoplasms using DNA recovered from cells shed into urine. UroSEEK incorporates massive parallel sequencing assays for mutations in 11 genes and copy number changes on 39 chromosome arms. In 570 patients at risk for bladder cancer (BC), UroSEEK was positive in 83% of those who developed BC. Combined with cytology, UroSEEK detected 95% of patients who developed BC. Of 56 patients with upper tract urothelial cancer, 75% tested positive by UroSEEK, including 79% of those with non-invasive tumors. UroSEEK detected genetic abnormalities in 68% of urines obtained from BC patients under surveillance who demonstrated clinical evidence of recurrence. The advantages of UroSEEK over cytology were evident in low-grade BCs; UroSEEK detected 67% of cases whereas cytology detected none. These results establish the foundation for a new non-invasive approach for detection of urothelial cancer.
Assuntos
Aneuploidia , Carcinoma de Células de Transição/diagnóstico , Detecção Precoce de Câncer/métodos , Mutação , Neoplasias da Bexiga Urinária/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células de Transição/genética , Carcinoma de Células de Transição/urina , Criança , Pré-Escolar , Feminino , Testes Genéticos/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Telomerase/genética , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/urina , Adulto JovemRESUMO
Environmental exposures pose a significant threat to human health. However, it is often difficult to study toxicological mechanisms in human subjects due to ethical concerns. Plant-derived aristolochic acids are among the most potent nephrotoxins and carcinogens discovered to date, yet the mechanism of bioactivation in humans remains poorly understood. Microphysiological systems (organs-on-chips) provide an approach to examining the complex, species-specific toxicological effects of pharmaceutical and environmental chemicals using human cells. We microfluidically linked a kidney-on-a-chip with a liver-on-a-chip to determine the mechanisms of bioactivation and transport of aristolochic acid I (AA-I), an established nephrotoxin and human carcinogen. We demonstrate that human hepatocyte-specific metabolism of AA-I substantially increases its cytotoxicity toward human kidney proximal tubular epithelial cells, including formation of aristolactam adducts and release of kidney injury biomarkers. Hepatic biotransformation of AA-I to a nephrotoxic metabolite involves nitroreduction, followed by sulfate conjugation. Here, we identify, in a human tissue-based system, that the sulfate conjugate of the hepatic NQO1-generated aristolactam product of AA-I (AL-I-NOSO3) is the nephrotoxic form of AA-I. This conjugate can be transported out of liver via MRP membrane transporters and then actively transported into kidney tissue via one or more organic anionic membrane transporters. This integrated microphysiological system provides an ex vivo approach for investigating organ-organ interactions, whereby the metabolism of a drug or other xenobiotic by one tissue may influence its toxicity toward another, and represents an experimental approach for studying chemical toxicity related to environmental and other toxic exposures.
Assuntos
Ácidos Aristolóquicos/toxicidade , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Animais , Biomarcadores , Biotransformação , Carcinógenos/toxicidade , Dicumarol/metabolismo , Células Epiteliais , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Rim/lesões , Masculino , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , NAD(P)H Desidrogenase (Quinona)/metabolismo , Néfrons/efeitos dos fármacos , Néfrons/metabolismo , Patologia Molecular/instrumentação , Patologia Molecular/métodos , Ratos , Ratos Sprague-Dawley , Insuficiência Renal Crônica , XenobióticosRESUMO
Formalin-fixed paraffin-embedded (FFPE) tissues are rarely used for screening DNA adducts of carcinogens because the harsh conditions required to reverse the formaldehyde-mediated DNA cross-links can destroy DNA adducts. We recently adapted a commercial silica-based column kit used in genomics to manually isolate DNA under mild conditions from FFPE tissues of rodents and humans and successfully measured DNA adducts of several carcinogens including aristolochic acid I (AA-I), 4-aminobiphenyl (4-ABP), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (Yun et al. (2013) Anal. Chem. 85, 4251-8, and Guo et al. (2016) Anal. Chem. 88, 4780-7). The DNA retrieval methodology is robust; however, the procedure is time-consuming and labor intensive, and not amenable to rapid throughput processing. In this study, we have employed the Promega Maxwell 16 MDx system, which is commonly used in large scale genomics studies, for the rapid throughput extraction of DNA. This system streamlines the DNA isolation procedure and increases the sample processing rate by about 8-fold over the manual method (32 samples versus 4 samples processed per hour). High purity DNA is obtained in satisfactory yield for the measurements of DNA adducts by ultra performance liquid chromatography-electrospray-ionization-ion trap-multistage scan mass spectrometry. The measurements show that the levels of DNA adducts of AA-I, 4-ABP, and PhIP in FFPE rodent and human tissues are comparable to those levels measured in DNA from matching tissues isolated by the commercial silica-based column kits and in DNA from fresh frozen tissues isolated by the conventional phenol-chloroform extraction method. The isolation of DNA from tissues is one major bottleneck in the analysis of DNA adducts. This rapid throughput methodology greatly decreases the time required to process DNA and can be employed in large-scale epidemiology studies designed to assess the role of chemical exposures and DNA adducts in cancer risk.
Assuntos
Carcinógenos/análise , Adutos de DNA/análise , DNA/isolamento & purificação , Formaldeído/química , Inclusão em Parafina , Fixação de Tecidos , Animais , Clorofórmio/química , Cromatografia Líquida de Alta Pressão , DNA/genética , Adutos de DNA/genética , Humanos , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos , Fenóis/química , Próstata/patologia , Espectrometria de Massas por Ionização por Electrospray , Fatores de TempoRESUMO
BACKGROUND: Aristolochia species used in the practice of traditional herbal medicine contains aristolochic acid (AA), an established human carcinogen contributing to urothelial carcinomas of the upper urinary tract. AA binds covalently to genomic DNA, forming aristolactam (AL)-DNA adducts. Here we investigated whether AA is also an etiologic factor in clear cell renal cell carcinoma (ccRCC). METHODS: We conducted a population-based case-control study to investigate the linkage between Aristolochia prescription history, cumulative AA consumption, and ccRCC incidence in Taiwan (5,709 cases and 22,836 matched controls). The presence and level of mutagenic dA-AL-I adducts were determined in the kidney DNA of 51 Taiwanese ccRCC patients. The whole-exome sequences of ccRCC tumors from 10 Taiwanese ccRCC patients with prior exposure to AA were determined. RESULTS: Cumulative ingestion of more than 250 mg of AA increased risk of ccRCC (OR, 1.25), and we detected dA-AL-I adducts in 76% of Taiwanese ccRCC patients. Furthermore, the distinctive AA mutational signature was evident in six of 10 sequenced ccRCC exomes from Taiwanese patients. CONCLUSIONS: This study strongly suggests that AA contributes to the etiology of certain RCCs. IMPACT: The current study offers compelling evidence implicating AA in a significant fraction of the RCC arising in Taiwan and illustrates the power of integrating epidemiologic, molecular, and genetic data in the investigation of cancer etiology. Cancer Epidemiol Biomarkers Prev; 25(12); 1600-8. ©2016 AACR.
Assuntos
Ácidos Aristolóquicos/toxicidade , Carcinoma de Células Renais/induzido quimicamente , Adutos de DNA/análise , Neoplasias Renais/induzido quimicamente , Rim/metabolismo , Mutação , Adulto , Idoso , Idoso de 80 Anos ou mais , Ácidos Aristolóquicos/análise , Ácidos Aristolóquicos/farmacologia , Carcinógenos/toxicidade , Carcinoma de Células Renais/epidemiologia , Carcinoma de Células Renais/genética , Estudos de Casos e Controles , DNA/efeitos dos fármacos , Análise Mutacional de DNA , Feminino , Humanos , Neoplasias Renais/epidemiologia , Neoplasias Renais/genética , Masculino , Pessoa de Meia-Idade , Mutagênicos/toxicidade , Taiwan/epidemiologiaRESUMO
TP53 mutation patterns are associated with prognosis of various cancers. This study was designed to investigate the association between TP53 mutation patterns and recurrence patterns in upper urinary tract urothelial carcinoma (UTUC) patients. A total of 165 consecutive UTUC patients who underwent nephroureterectomies were enrolled for measuring mutation patterns of TP53 gene from exome 2 to 11. Bladder recurrence, contralateral UTUC recurrence, and metastases were compared among groups by using log-rank test and Cox proportional hazard model. Single base substitution as an A:T to T:A transversion was noted in 55 (33.3%) patients (AT group). Forty-two (25.5%) patients had TP53 mutations with only other than A:T to T:A transversion (NAT group), and 68 patients (41.2%) had wide-type TP53 (WT group). AT group was predominately female (64%, 52%, 29%, respectively), had a higher incidence of end-stage renal disease (24%, 14%, 10%, respectively), and had more high-grade tumors (82%, 74%, 62%, respectively) compared to NAT and WT groups. With adjustment of tumor grade/stages, bladder and contralateral UTUC recurrence-free survival duration was shortest in NAT (p < 0.001) and AT group (p < 0.001), respectively. NAT group had a shorter metastasis-free survival duration than the other two groups combined (p = 0.018). As a result, A:T to T:A transversion increased contralateral UTUC recurrence risk, but other mutations in TP53 raised the hazard of bladder recurrence and metastases. Therefore, TP53 mutation pattern may be a useful biomarker to predict recurrence patterns of UTUC patients.
Assuntos
Genes p53 , Mutação , Recidiva Local de Neoplasia , Neoplasias da Bexiga Urinária/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Proteína Supressora de Tumor p53/análise , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia , Adulto JovemRESUMO
BACKGROUND: Dietary exposure to cytotoxic and carcinogenic aristolochic acid (AA) causes severe nephropathy typically associated with urologic cancers. Monitoring of AA exposure uses biomarkers such as aristolactam-DNA adducts, detected by mass spectrometry in the kidney cortex, or the somatic A>T transversion pattern characteristic of exposure to AA, as revealed by previous DNA-sequencing studies using fresh-frozen tumors. METHODS: Here, we report a low-coverage whole-exome sequencing method (LC-WES) optimized for multisample detection of the AA mutational signature, and demonstrate its utility in 17 formalin-fixed paraffin-embedded urothelial tumors obtained from 15 patients with endemic nephropathy, an environmental form of AA nephropathy. RESULTS: LC-WES identified the AA signature, alongside signatures of age and APOBEC enzyme activity, in 15 samples sequenced at the average per-base coverage of approximately 10×. Analysis at 3 to 9× coverage revealed the signature in 91% of the positive samples. The exome-wide distribution of the predominant A>T transversions exhibited a stochastic pattern, whereas 83 cancer driver genes were enriched for recurrent nonsynonymous A>T mutations. In two patients, pairs of tumors from different parts of the urinary tract, including the bladder, harbored overlapping mutation patterns, suggesting tumor dissemination via cell seeding. CONCLUSIONS: LC-WES analysis of archived tumor tissues is a reliable method applicable to investigations of both the exposure to AA and its biologic effects in human carcinomas. IMPACT: By detecting cancers associated with AA exposure in high-risk populations, LC-WES can support future molecular epidemiology studies and provide evidence-base for relevant preventive measures.
Assuntos
Ácidos Aristolóquicos/análise , Exoma/efeitos dos fármacos , Neoplasias/química , Neoplasias/genética , Carcinógenos/análise , Formaldeído , Humanos , Neoplasias/patologia , Inclusão em Parafina , Análise de Sequência de DNA/métodos , Fixação de TecidosRESUMO
Aristolochic acids (AA) are found in all Aristolochia herbaceous plants, many of which have been used worldwide for medicinal purposes for centuries. AA are causal agents of the chronic kidney disease entity termed aristolochic acid nephropathy (AAN) and potent upper urinary tract carcinogens in humans. AAN and upper urinary tract cancers are endemic in rural areas of Croatia and other Balkan countries where exposure to AA occurs through the ingestion of home-baked bread contaminated with Aristolochia seeds. In Asia, exposure to AA occurs through usage of traditional Chinese medicinal herbs containing Aristolochia. Despite warnings from regulatory agencies, traditional Chinese herbs containing AA continue to be used world-wide. In this review, we highlight novel approaches to quantify exposure to AA, by analysis of aristolactam (AL) DNA adducts, employing ultraperformance liquid chromatography-electrospray ionization/multistage mass spectrometry (UPLC-ESI/MSn). DNA adducts are a measure of internal exposure to AA and serve as an important end point for cross-species extrapolation of toxicity data and human risk assessment. The level of sensitivity of UPLC-ESI/MSn surpasses the limits of detection of AL-DNA adducts obtained by 32P-postlabeling techniques, the most widely employed methods for detecting putative DNA adducts in humans. AL-DNA adducts can be measured by UPLC-ESI/MS3, not only in fresh frozen renal tissue, but also in formalin-fixed, paraffin-embedded (FFPE) samples, an underutilized biospecimen for assessing chemical exposures, and in exfoliated urinary cells, a non-invasive approach. The frequent detection of AL DNA adducts in renal tissues, combined with the characteristic mutational spectrum induced by AA in TP53 and other genes provides compelling data for a role of AA in upper urothelial tract cancer.
RESUMO
Maintenance of mitochondrial structure and function is critical for preventing podocyte apoptosis and eventual glomerulosclerosis in the kidney; however, the transcription factors that regulate mitochondrial function in podocyte injury remain to be identified. Here, we identified Krüppel-like factor 6 (KLF6), a zinc finger domain transcription factor, as an essential regulator of mitochondrial function in podocyte apoptosis. We observed that podocyte-specific deletion of Klf6 increased the susceptibility of a resistant mouse strain to adriamycin-induced (ADR-induced) focal segmental glomerulosclerosis (FSGS). KLF6 expression was induced early in response to ADR in mice and cultured human podocytes, and prevented mitochondrial dysfunction and activation of intrinsic apoptotic pathways in these podocytes. Promoter analysis and chromatin immunoprecipitation studies revealed that putative KLF6 transcriptional binding sites are present in the promoter of the mitochondrial cytochrome c oxidase assembly gene (SCO2), which is critical for preventing cytochrome c release and activation of the intrinsic apoptotic pathway. Additionally, KLF6 expression was reduced in podocytes from HIV-1 transgenic mice as well as in renal biopsies from patients with HIV-associated nephropathy (HIVAN) and FSGS. Together, these findings indicate that KLF6-dependent regulation of the cytochrome c oxidase assembly gene is critical for maintaining mitochondrial function and preventing podocyte apoptosis.
Assuntos
Glomerulosclerose Segmentar e Focal/metabolismo , Infecções por HIV/complicações , Rim/metabolismo , Fatores de Transcrição Kruppel-Like/fisiologia , Mitocôndrias/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Animais , Apoptose , Sítios de Ligação , Células Cultivadas , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Glomerulosclerose Segmentar e Focal/patologia , Glomerulosclerose Segmentar e Focal/virologia , Infecções por HIV/metabolismo , HIV-1/fisiologia , Humanos , Rim/patologia , Fator 6 Semelhante a Kruppel , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Chaperonas Moleculares , Podócitos/fisiologia , Regiões Promotoras GenéticasRESUMO
BACKGROUND AND OBJECTIVES: Improvements in agricultural practices in Croatia have reduced exposure to consumption of aristolochic acid-contaminated flour and development of endemic (Balkan) nephropathy. Therefore, it was hypothesized that Bosnian immigrants who settled in an endemic area in Croatia 15-30 years ago would be at lower risk of developing endemic nephropathy because of reduced exposure to aristolochic acid. To test this hypothesis, past and present exposure to aristolochic acid, proximal tubule damage as a hallmark of endemic nephropathy, and prevalence of CKD in Bosnian immigrants were analyzed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this cross-sectional observational study from 2005 to 2010, 2161 farmers were divided into groups: indigenous inhabitants from endemic nephropathy and nonendemic nephropathy villages and Bosnian immigrants; α-1 microglobulin-to-creatinine ratio >31.5 mg/g and eGFR<60 ml/min per 1.73 m(2) were considered to be abnormal. RESULTS: CKD and proximal tubule damage prevalence was significantly lower in Bosnian immigrants than inhabitants of endemic nephropathy villages (6.9% versus 16.6%; P<0.001; 1.3% versus 7.3%; P=0.003, respectively); 20 years ago, Bosnian immigrants observed fewer Aristolochia clematitis in cultivated fields (41.9% versus 67.8%) and fewer seeds among wheat seeds (6.1% versus 35.6%) and ate more purchased than homemade bread compared with Croatian farmers from endemic nephropathy villages (38.5% versus 14.8%, P<0.001). Both Croatian farmers and Bosnian immigrants observe significantly fewer Aristolochia plants growing in their fields compared with 15-30 years ago. Prior aristolochic acid exposure was associated with proximal tubule damage (odds ratio, 1.64; 95% confidence interval, 1.04 to 2.58; P=0.02), whereas present exposure was not (odds ratio, 1.31; 95% confidence interval, 0.75 to 2.30; P=0.33). Furthermore, immigrant status was an independent negative predictor of proximal tubule damage (odds ratio, 0.40; 95% confidence interval, 0.19 to 0.86; P=0.02). CONCLUSIONS: Bosnian immigrants and autochthonous Croats residing in endemic areas are exposed significantly less to ingestion of aristolochic acid than in the past. The prevalence of endemic nephropathy and its associated urothelial cancers is predicted to decrease over time.
Assuntos
Doenças dos Trabalhadores Agrícolas/induzido quimicamente , Agricultura , Ácidos Aristolóquicos/efeitos adversos , Nefropatia dos Bálcãs/induzido quimicamente , Dieta/efeitos adversos , Emigrantes e Imigrantes , Contaminação de Alimentos , Túbulos Renais Proximais/efeitos dos fármacos , Exposição Ocupacional/efeitos adversos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doenças dos Trabalhadores Agrícolas/diagnóstico , Doenças dos Trabalhadores Agrícolas/etnologia , Doenças dos Trabalhadores Agrícolas/fisiopatologia , Doenças dos Trabalhadores Agrícolas/prevenção & controle , alfa-Globulinas/urina , Nefropatia dos Bálcãs/diagnóstico , Nefropatia dos Bálcãs/etnologia , Nefropatia dos Bálcãs/fisiopatologia , Nefropatia dos Bálcãs/prevenção & controle , Biomarcadores/sangue , Biomarcadores/urina , Bósnia e Herzegóvina/etnologia , Creatinina/sangue , Creatinina/urina , Croácia/epidemiologia , Estudos Transversais , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Humanos , Túbulos Renais Proximais/patologia , Túbulos Renais Proximais/fisiopatologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Exposição Ocupacional/prevenção & controle , Razão de Chances , Prevalência , Características de Residência , Fatores de Risco , Fatores de Tempo , Adulto JovemRESUMO
DNA adducts are a measure of internal exposure to genotoxicants. However, the measurement of DNA adducts in molecular epidemiology studies often is precluded by the lack of fresh tissue. In contrast, formalin-fixed paraffin-embedded (FFPE) tissues frequently are accessible, although technical challenges remain in retrieval of high quality DNA suitable for biomonitoring of adducts. Aristolochic acids (AA) are human carcinogens found in Aristolochia plants, some of which have been used in the preparation of traditional Chinese herbal medicines. We previously established a method to measure DNA adducts of AA in FFPE tissue. In this study, we examine additional features of formalin fixation that could impact the quantity and quality of DNA and report on the recovery of AA-DNA adducts in mice exposed to AA. The yield of DNA isolated from tissues fixed with formalin decreased over 1 week; however, the levels of AA-DNA adducts were similar to those in fresh frozen tissue. Moreover, DNA from FFPE tissue served as a template for PCR amplification, yielding sequence data of comparable quality to DNA obtained from fresh frozen tissue. The estimates of AA-DNA adducts measured in freshly frozen tissue and matching FFPE tissue blocks of human kidney stored for 9 years showed good concordance. Thus, DNA isolated from FFPE tissues may be used to biomonitor DNA adducts and to amplify genes used for mutational analysis, providing clues regarding the origin of human cancers for which an environmental cause is suspected.
Assuntos
Ácidos Aristolóquicos/metabolismo , Carcinógenos/metabolismo , Adutos de DNA/genética , Animais , Adutos de DNA/isolamento & purificação , Adutos de DNA/metabolismo , Análise Mutacional de DNA/normas , Fixadores/química , Formaldeído/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Inclusão em Parafina , Padrões de Referência , Espectrometria de Massas por Ionização por Electrospray/normas , Fixação de TecidosRESUMO
Aristolochic acids are potent human carcinogens; the role of phase II metabolism in their bioactivation is unclear. Accordingly, we tested the ability of the partially reduced metabolites, N-hydroxyaristolactams (AL-NOHs), and their N-O-sulfonated and N-O-acetylated derivatives to react with DNA to form aristolactam-DNA adducts. AL-NOHs displayed little or no activity in this regard while the sulfo- and acetyl compounds readily form DNA adducts, as detected by (32)P-post-labeling analysis. Mouse hepatic and renal cytosols stimulated binding of AL-NOHs to DNA in the presence of adenosine 3'-phosphate 5'-phosphosulfate (PAPS) but not of acetyl-CoA. Using Time of Flight liquid chromatography/mass spectrometry, N-hydroxyaristolactam I formed the sulfated compound in the presence of PAPS and certain human sulfotransferases, SULT1B1 >>> SULT1A2 > SULT1A1 >>> SULT1A3. The same pattern of SULT reactivity was observed when N-hydroxyaristolactam I was incubated with these enzymes and PAPS and the reaction was monitored by formation of aristolactam-DNA adducts. In the presence of human NAD(P)H: quinone oxidoreductase, the ability of aristolochic acid I to bind DNA covalently was increased significantly by addition of PAPS and SULT1B1. We conclude from these studies that AL-NOHs, formed following partial nitroreduction of aristolochic acids, serve as substrates for SULT1B1, producing N-sulfated esters, which, in turn, are converted to highly active species that react with DNA and, potentially, cellular proteins, resulting in the genotoxicity and nephrotoxicity associated with ingestion of aristolochic acids by humans.
Assuntos
Ácidos Aristolóquicos/farmacologia , Carcinógenos/farmacologia , Adutos de DNA/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Animais , Arilsulfotransferase/metabolismo , Western Blotting , Proliferação de Células , Células Cultivadas , Citosol/metabolismo , Adutos de DNA/metabolismo , Etanolaminas , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Rim/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C3H , Modelos Moleculares , Estrutura Molecular , NAD(P)H Desidrogenase (Quinona)/metabolismo , Oxirredutases/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Ácidos Esteáricos , Sulfotransferases/metabolismoRESUMO
Adipose tissue is a highly insulin-responsive organ that contributes to metabolic regulation. Insulin resistance in the adipose tissue affects systemic lipid and glucose homeostasis. Phosphoinositide 3-kinase (PI3K) mediates downstream insulin signaling in adipose tissue, but its physiological role in vivo remains unclear. Using Cre recombinase driven by the aP2 promoter, we created mice that lack the class 1A PI3K catalytic subunit p110α or p110ß specifically in the white and brown adipose tissue. The loss of p110α, not p110ß, resulted in increased adiposity, glucose intolerance and liver steatosis. Mice lacking p110α in adipose tissue exhibited a decrease in energy expenditure but no change in food intake or activity compared with control animals. This low energy expenditure is a consequence of low cellular respiration in the brown adipocytes caused by a decrease in expression of key mitochondrial genes including uncoupling protein-1. These results illustrate a critical role of p110α in the regulation of energy expenditure through modulation of cellular respiration in the brown adipose tissue and suggest that compromised insulin signaling in adipose tissue might be involved in the onset of obesity.