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Barutcu AR, Black MB, Samuel R, Slattery S, McMullen PD, Nong A. Integrating gene expression and splicing dynamics across dose-response oxidative modulators. Front Genet 2024; 15:1389095. [PMID: 38846964 PMCID: PMC11155298 DOI: 10.3389/fgene.2024.1389095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 05/06/2024] [Indexed: 06/09/2024] Open
Abstract
Toxicological risk assessment increasingly utilizes transcriptomics to derive point of departure (POD) and modes of action (MOA) for chemicals. One essential biological process that allows a single gene to generate several different RNA isoforms is called alternative splicing. To comprehensively assess the role of splicing dysregulation in toxicological evaluation and elucidate its potential as a complementary endpoint, we performed RNA-seq on A549 cells treated with five oxidative stress modulators across a wide dose range. Differential gene expression (DGE) showed limited pathway enrichment except at high concentrations. However, alternative splicing analysis revealed variable intron retention events affecting diverse pathways for all chemicals in the absence of significant expression changes. For instance, diazinon elicited negligible gene expression changes but progressive increase in the number of intron retention events, suggesting splicing alterations precede expression responses. Benchmark dose modeling of intron retention data highlighted relevant pathways overlooked by expression analysis. Systematic integration of splicing datasets should be a useful addition to the toxicogenomic toolkit. Combining both modalities paint a more complete picture of transcriptomic dose-responses. Overall, evaluating intron retention dynamics afforded by toxicogenomics may provide biomarkers that can enhance chemical risk assessment and regulatory decision making. This work highlights splicing-aware toxicogenomics as a possible additional tool for examining cellular responses.
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Banerjee M, Srivastava S, Rai SN, States JC. Chronic arsenic exposure induces malignant transformation of human HaCaT cells through both deterministic and stochastic changes in transcriptome expression. Toxicol Appl Pharmacol 2024; 484:116865. [PMID: 38373578 PMCID: PMC10994602 DOI: 10.1016/j.taap.2024.116865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/11/2024] [Accepted: 02/13/2024] [Indexed: 02/21/2024]
Abstract
Biological processes are inherently stochastic, i.e., are partially driven by hard to predict random probabilistic processes. Carcinogenesis is driven both by stochastic and deterministic (predictable non-random) changes. However, very few studies systematically examine the contribution of stochastic events leading to cancer development. In differential gene expression studies, the established data analysis paradigms incentivize expression changes that are uniformly different across the experimental versus control groups, introducing preferential inclusion of deterministic changes at the expense of stochastic processes that might also play a crucial role in the process of carcinogenesis. In this study, we applied simple computational techniques to quantify: (i) The impact of chronic arsenic (iAs) exposure as well as passaging time on stochastic gene expression and (ii) Which genes were expressed deterministically and which were expressed stochastically at each of the three stages of cancer development. Using biological coefficient of variation as an empirical measure of stochasticity we demonstrate that chronic iAs exposure consistently suppressed passaging related stochastic gene expression at multiple time points tested, selecting for a homogenous cell population that undergo transformation. Employing multiple balanced removal of outlier data, we show that chronic iAs exposure induced deterministic and stochastic changes in the expression of unique set of genes, that populate largely unique biological pathways. Together, our data unequivocally demonstrate that both deterministic and stochastic changes in transcriptome-wide expression are critical in driving biological processes, pathways and networks towards clonal selection, carcinogenesis, and tumor heterogeneity.
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Affiliation(s)
- Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA; Center for Integrative Environmental Health Sciences, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA
| | - Sudhir Srivastava
- Department of Bioinformatics and Biostatistics, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA
| | - Shesh N Rai
- Department of Bioinformatics and Biostatistics, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA; Biostatistics and Bioinformatics Facility, James Graham Brown Cancer Center, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA; Biostatistics and Informatics Facility Core, Center for Integrative Environmental Health Sciences, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA; Center for Integrative Environmental Health Sciences, University of Louisville, 505, S. Hancock Street, Louisville, KY 40202, USA.
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3
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Gao J, Li J, Zhang J, Sun Y, Ju X, Li W, Duan H, Xue Z, Sun L, Hussain Sahito J, Fu Z, Zhang X, Tang J. Identification of Novel QTL for Mercury Accumulation in Maize Using an Enlarged SNP Panel. Genes (Basel) 2024; 15:257. [PMID: 38397246 PMCID: PMC10888321 DOI: 10.3390/genes15020257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/14/2024] [Accepted: 02/17/2024] [Indexed: 02/25/2024] Open
Abstract
Mercury (Hg) pollution not only poses a threat to the environment but also adversely affects the growth and development of plants, with potential repercussions for animals and humans through bioaccumulation in the food chain. Maize, a crucial source of food, industrial materials, and livestock feed, requires special attention in understanding the genetic factors influencing mercury accumulation. Developing maize varieties with low mercury accumulation is vital for both maize production and human health. In this study, a comprehensive genome-wide association study (GWAS) was conducted using an enlarged SNP panel comprising 1.25 million single nucleotide polymorphisms (SNPs) in 230 maize inbred lines across three environments. The analysis identified 111 significant SNPs within 78 quantitative trait loci (QTL), involving 169 candidate genes under the Q model. Compared to the previous study, the increased marker density and optimized statistical model led to the discovery of 74 additional QTL, demonstrating improved statistical power. Gene ontology (GO) enrichment analysis revealed that most genes participate in arsenate reduction and stress responses. Notably, GRMZM2G440968, which has been reported in previous studies, is associated with the significant SNP chr6.S_155668107 in axis tissue. It encodes a cysteine proteinase inhibitor, implying its potential role in mitigating mercury toxicity by inhibiting cysteine. Haplotype analyses provided further insights, indicating that lines carrying hap3 exhibited the lowest mercury content compared to other haplotypes. In summary, our study significantly enhances the statistical power of GWAS, identifying additional genes related to mercury accumulation and metabolism. These findings offer valuable insights into unraveling the genetic basis of mercury content in maize and contribute to the development of maize varieties with low mercury accumulation.
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Affiliation(s)
- Jionghao Gao
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Jianxin Li
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Jihong Zhang
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Yan Sun
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Xiaolong Ju
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Wenlong Li
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Haiyang Duan
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Zhengjie Xue
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Li Sun
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Javed Hussain Sahito
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Zhiyuan Fu
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Xuehai Zhang
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
| | - Jihua Tang
- Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China; (J.G.); (J.L.); (J.Z.); (Y.S.); (X.J.); (W.L.); (H.D.); (Z.X.); (L.S.); (J.H.S.); (Z.F.)
- The Shennong Laboratory, Zhengzhou 450002, China
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Ferragut Cardoso AP, Nail AN, Banerjee M, Wise SS, States JC. miR-186 induces tetraploidy in arsenic exposed human keratinocytes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 256:114823. [PMID: 36989553 DOI: 10.1016/j.ecoenv.2023.114823] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/21/2023] [Accepted: 03/21/2023] [Indexed: 05/25/2023]
Abstract
Chronic inorganic arsenic (iAs) exposure in drinking water is a global issue affecting >225 million people. Skin is a major target organ for iAs. miRNA dysregulation and chromosomal instability (CIN) are proposed mechanisms of iAs-induced carcinogenesis. CIN is a cancer hallmark and tetraploid cells can better tolerate increase in chromosome number and aberration, contributing to the evolution of CIN. miR-186 is overexpressed in iAs-induced squamous cell carcinoma relative to iAs-induced hyperkeratosis. Bioinformatic analysis indicated that miR-186 targets mRNAs of important cell cycle regulators including mitotic checkpoint serine/threonine kinase B (BUB1) and cell division cycle 27 (CDC27). We hypothesized that miR-186 overexpression contributes to iAs-induced transformation of keratinocytes by targeting mitotic regulators leading to induction of CIN. Ker-CT cells, a near diploid human keratinocyte cell line, were transduced with miR-186 overexpressing or scrambled control lentivirus. Stable clones were isolated after puromycin selection. Clones transduced with lentivirus expressing either a scrambled control miRNA or miR-186 were maintained with 0 or 100 nM iAs for 4 weeks. Unexposed scrambled control clones were considered as passage matched controls. Chronic iAs exposure increased miR-186 expression in miR-186 clones. miR-186 overexpression significantly reduced CDC27 levels irrespective of iAs exposure. The percentage of tetraploid or aneuploid cells was increased in iAs exposed miR-186 clones. Aneuploidy can arise from a tetraploid intermediate. Suppression of CDC27 by miR-186 may lead to impairment of mitotic checkpoint complex formation and its ability to maintain cell cycle arrest leading to chromosome misalignment. As a result, cells overexpressing miR-186 and chronically exposed to iAs may have incorrect chromosome segregation and CIN. These data suggest that dysregulation of miRNA by iAs mediates tetraploidy, aneuploidy and chromosomal instability contributing to iAs-induced carcinogenesis.
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Affiliation(s)
- Ana P Ferragut Cardoso
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Alexandra N Nail
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - Sandra S Wise
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, 40202, USA.
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5
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Banerjee M, Yaddanapudi K, States JC. Zinc supplementation prevents mitotic accumulation in human keratinocyte cell lines upon environmentally relevant arsenic exposure. Toxicol Appl Pharmacol 2022; 454:116255. [PMID: 36162444 PMCID: PMC9683715 DOI: 10.1016/j.taap.2022.116255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/09/2022] [Accepted: 09/20/2022] [Indexed: 12/01/2022]
Abstract
Disrupted cell cycle progression underlies the molecular pathogenesis of multiple diseases. Chronic exposure to inorganic arsenic (iAs) is a global health issue leading to multi-organ cancerous and non-cancerous diseases. Exposure to supratherapeutic concentrations of iAs causes cellular accumulation in G2 or M phase of the cell cycle in multiple cell lines by inducing cyclin B1 expression. It is not clear if iAs exposure at doses corresponding to serum levels of chronically exposed populations (∼100 nM) has any effect on cell cycle distribution. In the present study we investigated if environmentally relevant iAs exposure induced cell cycle disruption and mechanisms thereof employing two human keratinocyte cell lines (HaCaT and Ker-CT), flow cytometry, immunoblots and quantitative real-time PCR (qRT-PCR). iAs exposure (100 nM; 24 h) led to mitotic accumulation of cells in both cell lines, along with the stabilization of ANAPC11 ubiquitination targets cyclin B1 and securin, without affecting their steady state mRNA levels. This result suggested that induction of cyclin B1 and securin is modulated at the level of protein degradation. Moreover, zinc supplementation successfully prevented iAs-induced mitotic accumulation and stabilization of cyclin B1 and securin without affecting their mRNA levels. Together, these data suggest that environmentally relevant iAs exposure leads to mitotic accumulation possibly by displacing zinc from the RING finger subunit of anaphase promoting complex/cyclosome (ANAPC11), the cell cycle regulating E3 ubiquitin ligase. This early cell cycle disruptive effect of environmentally relevant iAs concentration could underpin the molecular pathogenesis of multiple diseases associated with chronic iAs exposure.
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Affiliation(s)
- Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA.
| | - Kavitha Yaddanapudi
- Immuno-Oncology Group, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA; Department of Surgery, Division of Immunotherapy, University of Louisville, Louisville, KY, USA; Department of Microbiology/Immunology, University of Louisville, Louisville, KY, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
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6
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Arsenic impairs the lineage commitment of hematopoietic progenitor cells through the attenuation of GATA-2 DNA binding activity. Toxicol Appl Pharmacol 2022; 452:116193. [PMID: 35961411 DOI: 10.1016/j.taap.2022.116193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/28/2022] [Accepted: 08/05/2022] [Indexed: 11/22/2022]
Abstract
Arsenic exposure produces significant hematotoxicity in vitro and in vivo. Our previous work shows that arsenic (in the form of arsenite, AsIII) interacts with the zinc finger domains of GATA-1, inhibiting the function of this critical transcription factor, and resulting in the suppression of erythropoiesis. In addition to GATA-1, GATA-2 also plays a key role in the regulation of hematopoiesis. GATA-1 and GATA-2 have similar zinc finger domains (C4-type) that are structurally favorable for AsIII interactions. Taking this into consideration, we hypothesized that early stages of hematopoietic differentiation that are dependent on the function of GATA-2 may also be disrupted by AsIII exposure. We found that in vitro AsIII exposures disrupt the erythromegakaryocytic lineage commitment and differentiation of erythropoietin-stimulated primary mouse bone marrow hematopoietic progenitor cells (HPCs), producing an aberrant accumulation of cells in early stages of hematopoiesis and subsequent reduction of committed erythro-megakaryocyte progenitor cells. Arsenic significantly accumulated in the GATA-2 protein, causing the loss of zinc, and disruption of GATA-2 function, as measured by chromatin immunoprecipitation and the expression of GATA-2 responsive genes. Our results show that the attenuation of GATA-2 function is an important mechanism contributing to the aberrant lineage commitment and differentiation of early HPCs. Collectively, findings from the present study suggest that the AsIII-induced disruption of erythro-megakaryopoiesis may contribute to the onset and/or exacerbation of hematological disorders, such as anemia.
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Bastick JC, Banerjee M, States JC. Zinc supplementation prevents arsenic-induced dysregulation of ZRANB2 splice function. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 94:103921. [PMID: 35764259 PMCID: PMC9945473 DOI: 10.1016/j.etap.2022.103921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Environmentally relevant (100 nM) inorganic arsenic (iAs) exposure displaces zinc from zinc fingers of upstream splice regulator ZRANB2 disrupting the splicing of its target TRA2B. Excess zinc displaced iAs from ZRANB2 zinc fingers in cell free system. Thus, the hypothesis that zinc supplementation could prevent iAs-mediated disruption of ZRANB2 splice function in human keratinocytes was tested. The data show that zinc supplementation prevented iAs-induced dysregulation of TRA2B splicing by ZRANB2 as well as the induction of ZRANB2 protein expression. These results provide additional support for the hypothesis that zinc supplementation could prevent iAs-mediated disease in iAs-exposed populations.
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Affiliation(s)
- Jonathan C Bastick
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA
| | - Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA.
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Nail AN, McCaffrey LM, Banerjee M, Ferragut Cardoso AP, States JC. Chronic arsenic exposure suppresses ATM pathway activation in human keratinocytes. Toxicol Appl Pharmacol 2022; 446:116042. [DOI: 10.1016/j.taap.2022.116042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 01/15/2023]
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Ghosh S, Banerjee M, Haribabu B, Jala VR. Urolithin A attenuates arsenic-induced gut barrier dysfunction. Arch Toxicol 2022; 96:987-1007. [PMID: 35122514 PMCID: PMC10867785 DOI: 10.1007/s00204-022-03232-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/20/2022] [Indexed: 01/16/2023]
Abstract
Environmental chemicals such as inorganic arsenic (iAs) significantly contribute to redox toxicity in the human body by enhancing oxidative stress. Imbalanced oxidative stress rapidly interferes with gut homeostasis and affects variety of cellular processes such as proliferation, apoptosis, and maintenance of intestinal barrier integrity. It has been shown that gut microbiota are essential to protect against iAs3+-induced toxicity. However, the effect of microbial metabolites on iAs3+-induced toxicity and loss of gut barrier integrity has not been investigated. The objectives of the study are to investigate impact of iAs on gut barrier function and determine benefits of gut microbial metabolite, urolithin A (UroA) against iAs3+-induced adversaries on gut epithelium. We have utilized both colon epithelial cells and in a human intestinal 3D organoid model system to investigate iAs3+-induced cell toxicity, oxidative stress, and gut barrier dysfunction in the presence or absence of UroA. Here, we report that treatment with UroA attenuated iAs3+-induced cell toxicity, apoptosis, and oxidative stress in colon epithelial cells. Moreover, our data suggest that UroA significantly reduces iAs3+-induced gut barrier permeability and inflammatory markers in both colon epithelial cells and in a human intestinal 3D organoid model system. Mechanistically, UroA protected against iAs3+-induced disruption of tight junctional proteins in intestinal epithelial cells through blockade of oxidative stress and markers of inflammation. Taken together, our studies for the first time suggest that microbial metabolites such as UroA can potentially be used to protect against environmental hazards by reducing intestinal oxidative stress and by enhancing gut barrier function.
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Affiliation(s)
- Sweta Ghosh
- Department of Microbiology and Immunology, UofL Health-Brown Cancer Center, Center for Microbiomics, Inflammation and Pathogenicity, University of Louisville, 505 South Hancock Street # 323, Louisville, KY, 40202, USA
| | - Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
| | - Bodduluri Haribabu
- Department of Microbiology and Immunology, UofL Health-Brown Cancer Center, Center for Microbiomics, Inflammation and Pathogenicity, University of Louisville, 505 South Hancock Street # 323, Louisville, KY, 40202, USA
| | - Venkatakrishna Rao Jala
- Department of Microbiology and Immunology, UofL Health-Brown Cancer Center, Center for Microbiomics, Inflammation and Pathogenicity, University of Louisville, 505 South Hancock Street # 323, Louisville, KY, 40202, USA.
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Ferragut Cardoso AP, Banerjee M, Al-Eryani L, Sayed M, Wilkey DW, Merchant ML, Park JW, States JC. Temporal Modulation of Differential Alternative Splicing in HaCaT Human Keratinocyte Cell Line Chronically Exposed to Arsenic for up to 28 Wk. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:17011. [PMID: 35072517 PMCID: PMC8785870 DOI: 10.1289/ehp9676] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
BACKGROUND Chronic arsenic exposure via drinking water is associated with an increased risk of developing cancer and noncancer chronic diseases. Pre-mRNAs are often subject to alternative splicing, generating mRNA isoforms encoding functionally distinct protein isoforms. The resulting imbalance in isoform species can result in pathogenic changes in critical signaling pathways. Alternative splicing as a mechanism of arsenic-induced toxicity and carcinogenicity is understudied. OBJECTIVE This study aimed to accurately profile differential alternative splicing events in human keratinocytes induced by chronic arsenic exposure that might play a role in carcinogenesis. METHODS Independent quadruplicate cultures of immortalized human keratinocytes (HaCaT) were maintained continuously for 28 wk with 0 or 100 nM sodium arsenite. RNA-sequencing (RNA-Seq) was performed with poly(A) RNA isolated from cells harvested at 7, 19, and 28 wk with subsequent replicate multivariate analysis of transcript splicing (rMATS) analysis to detect and quantify differential alternative splicing events. Reverse transcriptase-polymerase chain reaction (RT-PCR) for selected alternative splicing events was performed to validate RNA-Seq predictions. Functional enrichment was performed by gene ontology (GO) analysis of the differential alternative splicing event data set at each time point. RESULTS At least 600 differential alternative splicing events were detected at each time point tested, comprising all the five main types of alternative splicing and occurring in both open reading frames (ORFs) and untranslated regions (UTRs). Based on functional relevance ELK4, SHC1, and XRRA1 were selected for validation of predicted alternative splicing events at 7 wk by RT-PCR. Densitometric analysis of RT-PCR data corroborated the rMATS predicted alternative splicing for all three events. Protein expression validation of the selected alternative splicing events was challenging given that very few isoform-specific antibodies are available. GO analysis demonstrated that the enriched terms in differential alternatively spliced mRNAs changed dynamically with the time of exposure. Notably, RNA metabolism and splicing regulation pathways were enriched at the 7-wk time point, when the greatest number of differentially alternatively spliced mRNAs are detected. Our preliminary proteomic analysis demonstrated that the expression of the canonical isoforms of the splice regulators DDX42, RMB25, and SRRM2 were induced upon chronic arsenic exposure, corroborating the splicing predictions. DISCUSSION These results using cultures of HaCaT cells suggest that arsenic exposure disrupted an alternative splice factor network and induced time-dependent genome-wide differential alternative splicing that likely contributed to the changing proteomic landscape in arsenic-induced carcinogenesis. However, significant challenges remain in corroborating alternative splicing data at the proteomic level. https://doi.org/10.1289/EHP9676.
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Affiliation(s)
- Ana P. Ferragut Cardoso
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Laila Al-Eryani
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Mohammed Sayed
- Computer Science and Engineering, University of Louisville, Louisville, Kentucky, USA
| | - Daniel W. Wilkey
- Division of Nephrology & Hypertension, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Michael L. Merchant
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
- Division of Nephrology & Hypertension, Department of Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Juw W. Park
- Computer Science and Engineering, University of Louisville, Louisville, Kentucky, USA
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, Kentucky, USA
| | - J. Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
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11
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Vergara-Gerónimo CA, León Del Río A, Rodríguez-Dorantes M, Ostrosky-Wegman P, Salazar AM. Arsenic-protein interactions as a mechanism of arsenic toxicity. Toxicol Appl Pharmacol 2021; 431:115738. [PMID: 34619159 DOI: 10.1016/j.taap.2021.115738] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/28/2021] [Accepted: 09/30/2021] [Indexed: 12/13/2022]
Abstract
Millions of people worldwide are exposed to arsenic, a metalloid listed as one of the top chemical pollutants of concern to human health. Epidemiological and experimental studies link arsenic exposure to the development of cancer and other diseases. Several mechanisms have been proposed to explain the effects induced by arsenic. Notably, arsenic and its metabolites interact with proteins by direct binding to individual cysteine residues, cysteine clusters, zinc finger motifs, and RING finger domains. Consequently, arsenic interactions with proteins disrupt the functions of proteins and may lead to the development and progression of diseases. In this review, we focus on current evidence in the literature that implicates the interaction of arsenic with proteins as a mechanism of arsenic toxicity. Data show that arsenic-protein interactions affect multiple cellular processes and alter epigenetic regulation, cause endocrine disruption, inhibit DNA damage repair mechanisms, and deregulate gene expression, among other adverse effects.
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Affiliation(s)
- Cristian A Vergara-Gerónimo
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Apartado Postal 70228, Ciudad de México, Mexico
| | - Alfonso León Del Río
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Apartado Postal 70228, Ciudad de México, Mexico
| | | | - Patricia Ostrosky-Wegman
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Apartado Postal 70228, Ciudad de México, Mexico
| | - Ana María Salazar
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Apartado Postal 70228, Ciudad de México, Mexico.
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12
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Saintilnord WN, Fondufe-Mittendorf Y. Arsenic-induced epigenetic changes in cancer development. Semin Cancer Biol 2021; 76:195-205. [PMID: 33798722 PMCID: PMC8481342 DOI: 10.1016/j.semcancer.2021.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/29/2022]
Abstract
Arsenic is a ubiquitous metalloid whose high levels of toxicity pose major health concerns to millions of people worldwide by increasing susceptibility to various cancers and non-cancer illnesses. Since arsenic is not a mutagen, the mechanism by which it causes changes in gene expression and disease pathogenesis is not clear. One possible mechanism is through generation of reactive oxygen species. Another equally important mechanism still very much in its infancy is epigenetic dysregulation. In this review, we discuss recent discoveries underlying arsenic-induced epigenetic changes in cancer development. Importantly, we highlight the proposed mechanisms targeted by arsenic to drive oncogenic gene expression.
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Affiliation(s)
- Wesley N Saintilnord
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA.
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13
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Danes JM, Palma FR, Bonini MG. Arsenic and other metals as phenotype driving electrophiles in carcinogenesis. Semin Cancer Biol 2021; 76:287-291. [PMID: 34563651 DOI: 10.1016/j.semcancer.2021.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 12/17/2022]
Abstract
There are several sources of heavy metal exposures whether occupational or environmental. These are connected both with the existence of natural reservoirs of metal toxicants or human activity such as mining, welding and construction. In general, exposure to heavy metals, such as cadmium (Cd), mercury (Hg), nickel (Ni), lead (Pb) and metalloids, such as arsenic (As), has been associated with diseases including neurodegenerative diseases, diabetes and cancer. Common to these diseases is the loss of cellular physiologic performance and phenotype required for proper function. On the metal side, electrophilic behavior that disrupts the electronic (or redox) state of cells is a common feature. This suggests that there may be a connection between changes to the redox equilibrium of cells caused by environmental exposures to heavy metals and the pathogenic effects of such exposures. In this mini-review, we will focus on two environmental contaminants cadmium (a metal) and arsenic (a metalloid) and explore their interactions with living organisms from the perspective of their electrophilic chemical reactivity that underlies both their potential as carcinogens and as drivers of more aggressive tumor phenotypes.
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Affiliation(s)
- Jeanne M Danes
- Department of Medicine, Division of Hematology Oncology, Northwestern University Feinberg School of Medicine and the Robert H. Lurie Comprehensive Cancer Center of Chicago, United States
| | - Flavio R Palma
- Department of Medicine, Division of Hematology Oncology, Northwestern University Feinberg School of Medicine and the Robert H. Lurie Comprehensive Cancer Center of Chicago, United States
| | - Marcelo G Bonini
- Department of Medicine, Division of Hematology Oncology, Northwestern University Feinberg School of Medicine and the Robert H. Lurie Comprehensive Cancer Center of Chicago, United States.
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14
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Banerjee M, Ferragut Cardoso A, Al-Eryani L, Pan J, Kalbfleisch TS, Srivastava S, Rai SN, States JC. Dynamic alteration in miRNA and mRNA expression profiles at different stages of chronic arsenic exposure-induced carcinogenesis in a human cell culture model of skin cancer. Arch Toxicol 2021; 95:2351-2365. [PMID: 34032870 PMCID: PMC8241660 DOI: 10.1007/s00204-021-03084-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/17/2021] [Indexed: 12/22/2022]
Abstract
Chronic arsenic exposure causes skin cancer, although the underlying molecular mechanisms are not well defined. Altered microRNA and mRNA expression likely play a pivotal role in carcinogenesis. Changes in genome-wide differential expression of miRNA and mRNA at 3 strategic time points upon chronic sodium arsenite (As3+) exposure were investigated in a well-validated HaCaT cell line model of arsenic-induced cutaneous squamous cell carcinoma (cSCC). Quadruplicate independent HaCaT cell cultures were exposed to 0 or 100 nM As3+ for up to 28-weeks (wk). Cell growth was monitored throughout the course of exposure and epithelial-mesenchymal transition (EMT) was examined employing immunoblot. Differentially expressed miRNA and mRNA profiles were generated at 7, 19, and 28-wk by RNA-seq, followed by identification of differentially expressed mRNA targets of differentially expressed miRNAs through expression pairing at each time point. Pathway analyses were performed for total differentially expressed mRNAs and for the miRNA targeted mRNAs at each time point. RNA-seq predictions were validated by immunoblot of selected target proteins. While the As3+-exposed cells grew slower initially, growth was equal to that of unexposed cells by 19-wk (transformation initiation), and exposed cells subsequently grew faster than passage-matched unexposed cells. As3+-exposed cells had undergone EMT at 28-wk. Pathway analyses demonstrate dysregulation of carcinogenesis-related pathways and networks in a complex coordinated manner at each time point. Immunoblot data largely corroborate RNA-seq predictions in the endoplasmic reticulum stress (ER stress) pathway. This study provides a detailed molecular picture of changes occurring during the arsenic-induced transformation of human keratinocytes.
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Affiliation(s)
- Mayukh Banerjee
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
| | - Ana Ferragut Cardoso
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
| | - Laila Al-Eryani
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA
- Knowledge Management and Special Projects Branch, Center for Strategic Scientific Initiatives (HNC1L), National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jianmin Pan
- Biostatistics and Bioinformatics Facility, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
- Biostatistics and Informatics Facility, Center for Integrative Environmental Health Sciences, University of Louisville, Louisville, KY, USA
| | - Theodore S Kalbfleisch
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY, USA
- Gluck Equine Research Center, University of Kentucky, Lexington, KY, USA
| | - Sudhir Srivastava
- Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA
- Centre for Agricultural Bioinformatics, ICAR-Indian Agricultural Statistics Research Institute, New Delhi, 110012, India
| | - Shesh N Rai
- Biostatistics and Bioinformatics Facility, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
- Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA
- Biostatistics and Informatics Facility, Center for Integrative Environmental Health Sciences, University of Louisville, Louisville, KY, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY, USA.
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