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Du K, Ricci JMB, Lu Y, Garcia-Olazabal M, Walter RB, Warren WC, Dodge TO, Schumer M, Park H, Meyer A, Schartl M. Phylogenomic analyses of all species of swordtail fishes (genus Xiphophorus) show that hybridization preceded speciation. Nat Commun 2024; 15:6609. [PMID: 39098897 PMCID: PMC11298535 DOI: 10.1038/s41467-024-50852-6] [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: 12/31/2023] [Accepted: 07/16/2024] [Indexed: 08/06/2024] Open
Abstract
Hybridization has been recognized to play important roles in evolution, however studies of the genetic consequence are still lagging behind in vertebrates due to the lack of appropriate experimental systems. Fish of the genus Xiphophorus are proposed to have evolved with multiple ancient and ongoing hybridization events. They have served as an informative research model in evolutionary biology and in biomedical research on human disease for more than a century. Here, we provide the complete genomic resource including annotations for all described 26 Xiphophorus species and three undescribed taxa and resolve all uncertain phylogenetic relationships. We investigate the molecular evolution of genes related to cancers such as melanoma and for the genetic control of puberty timing, focusing on genes that are predicted to be involved in pre-and postzygotic isolation and thus affect hybridization. We discovered dramatic size-variation of some gene families. These persisted despite reticulate evolution, rapid speciation and short divergence time. Finally, we clarify the hybridization history in the entire genus settling disputed hybridization history of two Southern swordtails. Our comparative genomic analyses revealed hybridization ancestries that are manifested in the mosaic fused genomes and show that hybridization often preceded speciation.
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Du K, Lu Y, Garcia-Olazabal M, Walter RB, Warren WC, Dodge T, Schumer M, Park H, Meyer A, Schartl M. Phylogenomics analyses of all species of Swordtails (Genus Xiphophorus ) highlights hybridization precedes speciation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573732. [PMID: 38260540 PMCID: PMC10802237 DOI: 10.1101/2023.12.30.573732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Hybridization has been recognized as an important driving force for evolution, however studies of the genetic consequence and its cause are still lagging behind in vertebrates due to the lack of appropriate experimental systems. Fish of the central American genus Xiphophorus were proposed to have evolved with multiple ancient and ongoing hybridization events, and served as a valuable research model in evolutionary biology and in biomedical research on human disease for more than a century. Here, we provide the complete genome resource and its annotation of all 26 Xiphophorus species. On this dataset we resolved the so far conflicting phylogeny. Through comparative genomic analyses we investigated the molecular evolution of genes related to melanoma, for a main sexually selected trait and for the genetic control of puberty timing, which are predicted to be involved in pre-and postzygotic isolation and thus to influence the probability of interspecific hybridization in Xiphophorus . We demonstrate dramatic size-variation of some gene families across species, despite the reticulate evolution and short divergence time. Finally, we clarify the hybridization history in the genus Xiphophorus genus, settle the long dispute on the hybridization origin of two Southern swordtails, highlight hybridizations precedes speciation, and reveal the distribution of hybridization ancestry remaining in the fused genome.
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Lu Y, Rice E, Du K, Kneitz S, Naville M, Dechaud C, Volff JN, Boswell M, Boswell W, Hillier L, Tomlinson C, Milin K, Walter RB, Schartl M, Warren WC. High resolution genomes of multiple Xiphophorus species provide new insights into microevolution, hybrid incompatibility, and epistasis. Genome Res 2023; 33:557-571. [PMID: 37147111 PMCID: PMC10234306 DOI: 10.1101/gr.277434.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 03/29/2023] [Indexed: 05/07/2023]
Abstract
Because of diverged adaptative phenotypes, fish species of the genus Xiphophorus have contributed to a wide range of research for a century. Existing Xiphophorus genome assemblies are not at the chromosomal level and are prone to sequence gaps, thus hindering advancement of the intra- and inter-species differences for evolutionary, comparative, and translational biomedical studies. Herein, we assembled high-quality chromosome-level genome assemblies for three distantly related Xiphophorus species, namely, X. maculatus, X. couchianus, and X. hellerii Our overall goal is to precisely assess microevolutionary processes in the clade to ascertain molecular events that led to the divergence of the Xiphophorus species and to progress understanding of genetic incompatibility to disease. In particular, we measured intra- and inter-species divergence and assessed gene expression dysregulation in reciprocal interspecies hybrids among the three species. We found expanded gene families and positively selected genes associated with live bearing, a special mode of reproduction. We also found positively selected gene families are significantly enriched in nonpolymorphic transposable elements, suggesting the dispersal of these nonpolymorphic transposable elements has accompanied the evolution of the genes, possibly by incorporating new regulatory elements in support of the Britten-Davidson hypothesis. We characterized inter-specific polymorphisms, structural variants, and polymorphic transposable element insertions and assessed their association to interspecies hybridization-induced gene expression dysregulation related to specific disease states in humans.
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Speer RM, Meaza I, Toyoda JH, Lu Y, Xu Q, Walter RB, Kong M, Lu H, Kouokam JC, Wise JP. Particulate hexavalent chromium alters microRNAs in human lung cells that target key carcinogenic pathways. Toxicol Appl Pharmacol 2022; 438:115890. [PMID: 35101437 PMCID: PMC8938933 DOI: 10.1016/j.taap.2022.115890] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 12/20/2021] [Accepted: 01/17/2022] [Indexed: 10/19/2022]
Abstract
Hexavalent chromium [Cr(VI)] is a global environmental pollutant and human lung carcinogen. However, the mechanisms of Cr(VI) carcinogenesis are not well defined. Cr(VI)-altered gene expression has been reported in the literature and is implicated in numerous mechanisms of Cr(VI) carcinogenesis. MicroRNAs (miRNAs) play a key role in controlling gene expression and are associated with carcinogenic mechanisms. To date no studies have evaluated global changes in miRNA expression in human cells after Cr(VI) exposure. We used RNA sequencing to evaluate how a particulate Cr(VI) compound (zinc chromate), the most potent form of Cr(VI), alters global miRNA expression after acute (24 h) or prolonged (72 and 120 h) exposure to 0.1, 0.2 and 0.3 μg/cm2 zinc chromate in an immortalized, non-cancerous human lung cell line (WTHBF-6). Particulate Cr(VI) significantly affected expression of miRNAs at all time points and concentrations tested. We also found the number of significantly downregulated miRNAs increased in a time- and concentration-dependent manner and many miRNAs were upregulated after 24 h exposure at the intermediate concentration tested. Pathway analyses of the differentially expressed miRNAs predicted miRNAs target pathways of Cr(VI) carcinogenesis in a time- and concentration-dependent manner. These data are the first to evaluate global changes in miRNA expression in human lung cells after Cr(VI) exposure and indicate miRNAs may play a key role in pathways of Cr(VI) carcinogenesis.
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Lu Y, Bierbach D, Ormanns J, Warren WC, Walter RB, Schartl M. Fixation of allelic gene expression landscapes and expression bias pattern shape the transcriptome of the clonal Amazon molly. Genome Res 2021; 31:372-379. [PMID: 33547183 PMCID: PMC7919451 DOI: 10.1101/gr.268870.120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 01/12/2021] [Indexed: 02/07/2023]
Abstract
The Amazon molly is a unique clonal fish species that originated from an interspecies hybrid between Poecilia species P. mexicana and P. latipinna. It reproduces by gynogenesis, which eliminates paternal genomic contribution to offspring. An earlier study showed that Amazon molly shows biallelic expression for a large portion of the genome, leading to two main questions: (1) Are the allelic expression patterns from the initial hybridization event stabilized or changed during establishment of the asexual species and its further evolution? (2) Is allelic expression biased toward one parental allele a stochastic or adaptive process? To answer these questions, the allelic expression of P. formosa siblings was assessed to investigate intra- and inter-cohort allelic expression variability. For comparison, interspecies hybrids between P. mexicana and P. latipinna were produced in the laboratory to represent the P. formosa ancestor. We have identified inter-cohort and intra-cohort variation in parental allelic expression. The existence of inter-cohort divergence suggests functional P. formosa allelic expression patterns do not simply reflect the atavistic situation of the first interspecies hybrid but potentially result from long-term selection of transcriptional fitness. In addition, clonal fish show a transcriptional trend representing minimal intra-clonal variability in allelic expression patterns compared to the corresponding hybrids. The intra-clonal similarity in gene expression translates to sophisticated genetic functional regulation at the individuum level. These findings suggest the parental alleles inherited by P. formosa form tightly regulated genetic networks that lead to a stable transcriptomic landscape within clonal individuals.
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Lu Y, Boswell M, Boswell W, Salinas RY, Savage M, Reyes J, Walter S, Marks R, Gonzalez T, Medrano G, Warren WC, Schartl M, Walter RB. Global assessment of organ specific basal gene expression over a diurnal cycle with analyses of gene copies exhibiting cyclic expression patterns. BMC Genomics 2020; 21:787. [PMID: 33176680 PMCID: PMC7659085 DOI: 10.1186/s12864-020-07202-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 10/28/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Studying functional divergences between paralogs that originated from genome duplication is a significant topic in investigating molecular evolution. Genes that exhibit basal level cyclic expression patterns including circadian and light responsive genes are important physiological regulators. Temporal shifts in basal gene expression patterns are important factors to be considered when studying genetic functions. However, adequate efforts have not been applied to studying basal gene expression variation on a global scale to establish transcriptional activity baselines for each organ. Furthermore, the investigation of cyclic expression pattern comparisons between genome duplication created paralogs, and potential functional divergence between them has been neglected. To address these questions, we utilized a teleost fish species, Xiphophorus maculatus, and profiled gene expression within 9 organs at 3-h intervals throughout a 24-h diurnal period. RESULTS Our results showed 1.3-21.9% of genes in different organs exhibited cyclic expression patterns, with eye showing the highest fraction of cycling genes while gonads yielded the lowest. A majority of the duplicated gene pairs exhibited divergences in their basal level expression patterns wherein only one paralog exhibited an oscillating expression pattern, or both paralogs exhibit oscillating expression patterns, but each gene duplicate showed a different peak expression time, and/or in different organs. CONCLUSIONS These observations suggest cyclic genes experienced significant sub-, neo-, or non-functionalization following the teleost genome duplication event. In addition, we developed a customized, web-accessible, gene expression browser to facilitate data mining and data visualization for the scientific community.
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Lu Y, Olivas TJ, Boswell M, Boswell W, Warren WC, Schartl M, Walter RB. Intra-Strain Genetic Variation of Platyfish ( Xiphophorus maculatus) Strains Determines Tumorigenic Trajectory. Front Genet 2020; 11:562594. [PMID: 33133148 PMCID: PMC7573281 DOI: 10.3389/fgene.2020.562594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/09/2020] [Indexed: 11/16/2022] Open
Abstract
Xiphophorus interspecies hybrids represent a valuable model system to study heritable tumorigenesis, and the only model system that exhibits both spontaneous and inducible tumors. Types of tumorigenesis depend on the specific pedigree of the parental species, X. maculatus, utilized to produce interspecies hybrids. Although the ancestors of the two currently used X. maculatus parental lines, Jp163 A and Jp163 B, were originally siblings produced by the same mother, backcross interspecies hybrid progeny between X. hellerii and X. maculatus Jp163 A develop spontaneous melanoma initiating at the dorsal fin due to segregation of an oncogene and a regulator encoded by the X. maculatus genome, while the backcross hybrid progeny with X. hellerii or X. couchianus and Jp163 B exhibit melanoma on the flanks of their bodies, especially after treatment with ultraviolet light. Therefore, dissecting the genetic differences between these two closely related lines may lead to better understanding of functional molecular differences associated with tumorigenic mechanisms. For this purpose, comparative genomic analyses were undertaken to establish genetic variants between these two X. maculatus lines. Surprisingly, given the heritage of these two fish lines, we found genetic variants are clustered together in select chromosomal regions. Among these variants are non-synonymous mutations located in 381 genes. The non-random distribution of genetic variants between these two may highlight ancestral chromosomal recombination patterns that became fixed during subsequent inbreeding. Employing comparative transcriptomics, we also determined differences in the skin transcriptional landscape between the two lines. The genetic differences observed are associated with pathways highlighting fundamental cellular functions including inter-cellular and microenvironment-cellular interactions, and DNA repair. These results collectively lead to the conclusion that diverged functional genetic baselines are present between Jp163 A and B strains. Further, disruption of these fixed genetic baselines in the hybrids may give rise to spontaneous or inducible mechanisms of tumorigenesis.
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Childress WM, Bosworth B, Chesney E, Walter RB, Tiersch TR. On-Site Capabilities of a Mobile Laboratory for Aquatic Germplasm Cryopreservation. NORTH AMERICAN JOURNAL OF AQUACULTURE 2019; 81:349-363. [PMID: 31736675 PMCID: PMC6857928 DOI: 10.1002/naaq.10099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/16/2019] [Indexed: 05/08/2023]
Abstract
Cryopreservation of genetic material can become an important tool for user groups in imperiled fishes, wild fisheries, aquaculture, and biomedical research. Persistent challenges within aquatic species cryopreservation are standardization and reliable collection of diverse, high quality samples. The overall goal of this study was to work with different user groups and cryopreserve sperm on-site at their facilities to evaluate the uses and challenges of a mobile laboratory with high-throughput and quality control capabilities comparable to those of a specialized centralized facility. The objectives were to demonstrate collection and cryopreservation of sperm of: 1) large-bodied freshwater Blue Catfish (Ictalurus furcatus) for aquaculture; 2) small-bodied freshwater Xiphophorus for biomedical and imperiled repository development, and 3) saltwater Red Snapper (Lutjanus campechanus) for wild fisheries research. Over the course of this project, the mobile laboratory traveled more than 4,000 km collecting germplasm from more than 650 male fishes. A total of 136 Blue Catfish were processed in 2015 and 2016 resulting in a total of 6,146 0.5-mL French straws. A total of 521 males from 11 different species in the genus Xiphophorus were processed over 4 d in 2015 resulting in a total of 488 0.25-mL French straws. And, a total of 17 Red Snapper males were processed during 2015 resulting in a total of 316 0.5-mL French straws. This is the first development of a mobile laboratory with high-throughput capability for aquatic species. User groups would no longer be limited to germplasm resources that can only be shipped as samples or transported as live animals to a central cryopreservation facility. Mobile laboratories create opportunities to collect higher quality germplasm, provide access to new species, and enable direct cooperation, including training, with a wide variety of user groups and applications.
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Hagedorn M, Varga Z, Walter RB, Tiersch TR. Workshop report: Cryopreservation of aquatic biomedical models. Cryobiology 2019; 86:120-129. [PMID: 30389588 PMCID: PMC9903301 DOI: 10.1016/j.cryobiol.2018.10.264] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/23/2018] [Accepted: 10/26/2018] [Indexed: 02/06/2023]
Abstract
The genetic resources of aquatic biomedical model organisms are the products of millions of years of evolution, decades of scientific development, and hundreds of millions of dollars of research funding investment. Genetic resources (e.g., specific alleles, transgenes, or combinations) of each model organism can be considered a form of scientific wealth that can be accumulated and exchanged, typically in the form of live animals or germplasm. Large-scale maintenance of live aquatic organisms that carry these genetic resources is inefficient, costly, and risky. In situ maintenance may be substantially enhanced and backed up by combining cryopreserved germplasm repositories and genetic information systems with live animal culture. Unfortunately, cryopreservation has not advanced much beyond the status of an exploratory research for most aquatic species, lacks widespread application, and methods for successful cryopreservation remain poorly defined. For most aquatic species biological materials other than sperm or somatic cells are not comprehensively banked to represent and preserve a broad range of genetic diversity for each species. Therefore, new approaches and standardization are needed for repository-level application to ensure reproducible recovery of cryopreserved materials. Additionally, development of new technologies is needed to address preservation of novel biological materials, such as eggs and embryos of aquatic species. To address these goals, the Office of Research Infrastructure Programs (ORIP) of the National Institutes of Health (NIH) hosted the Cryopreservation of Aquatic Biomedical Models Workshop on January 7 to 8, 2017, in conjunction with the 8th Aquatic Animal Models of Human Disease Conference in Birmingham, Alabama. The goals of the workshop were to assess the status of germplasm cryopreservation in various biomedical aquatic models and allow representatives of the scientific community to develop and prioritize a consensus of specific actionable recommendations that will move the field of cryopreservation of aquatic resources forward. This workshop included sessions devoted to new approaches for cryopreservation of aquatic species, discussion of current efforts and approaches in preservation of aquatic model germplasm, consideration of needs for standardization of methods to support reproducibility, and enhancement of repository development by establishment of scalable high-throughput technologies. The following three broad recommendations were forwarded from workshop attendees: 1: Establish a comprehensive, centralized unit ("hub") to programmatically develop training for and documentation of cryopreservation methods for aquatic model systems. This would include development of species-specific protocols and approaches, outreach programs, community development and standardization, freezing services and training of the next generation of experts in aquatic cryopreservation. 2: Provide mechanisms to support innovative technical advancements that will increase the reliability, reproducibility, simplicity, throughput, and efficiency of the cryopreservation process, including vitrification and pipelines for sperm, oocytes, eggs, embryos, larvae, stem cells, and somatic cells of all aquatic species. This recommendation encompasses basic cryopreservation knowledge and engineering technology, such as microfluidics and automated processing technologies. 3: Implement mechanisms that allow the various aquatic model stock centers to increase their planning, personnel, ability to secure genetic resources and to promote interaction within an integrated, comprehensive repository network for aquatic model species repositories.
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Lu Y, Boswell W, Boswell M, Klotz B, Kneitz S, Regneri J, Savage M, Mendoza C, Postlethwait J, Warren WC, Schartl M, Walter RB. Application of the Transcriptional Disease Signature (TDSs) to Screen Melanoma-Effective Compounds in a Small Fish Model. Sci Rep 2019; 9:530. [PMID: 30679619 PMCID: PMC6345854 DOI: 10.1038/s41598-018-36656-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/22/2018] [Indexed: 12/20/2022] Open
Abstract
Cell culture and protein target-based compound screening strategies, though broadly utilized in selecting candidate compounds, often fail to eliminate candidate compounds with non-target effects and/or safety concerns until late in the drug developmental process. Phenotype screening using intact research animals is attractive because it can help identify small molecule candidate compounds that have a high probability of proceeding to clinical use. Most FDA approved, first-in-class small molecules were identified from phenotypic screening. However, phenotypic screening using rodent models is labor intensive, low-throughput, and very expensive. As a novel alternative for small molecule screening, we have been developing gene expression disease profiles, termed the Transcriptional Disease Signature (TDS), as readout of small molecule screens for therapeutic molecules. In this concept, compounds that can reverse, or otherwise affect known disease-associated gene expression patterns in whole animals may be rapidly identified for more detailed downstream direct testing of their efficacy and mode of action. To establish proof of concept for this screening strategy, we employed a transgenic strain of a small aquarium fish, medaka (Oryzias latipes), that overexpresses the malignant melanoma driver gene xmrk, a mutant egfr gene, that is driven by a pigment cell-specific mitf promoter. In this model, melanoma develops with 100% penetrance. Using the transgenic medaka malignant melanoma model, we established a screening system that employs the NanoString nCounter platform to quantify gene expression within custom sets of TDS gene targets that we had previously shown to exhibit differential transcription among xmrk-transgenic and wild-type medaka. Compound-modulated gene expression was identified using an internet-accessible custom-built data processing pipeline. The effect of a given drug on the entire TDS profile was estimated by comparing compound-modulated genes in the TDS using an activation Z-score and Kolmogorov-Smirnov statistics. TDS gene probes were designed that target common signaling pathways that include proliferation, development, toxicity, immune function, metabolism and detoxification. These pathways may be utilized to evaluate candidate compounds for potential favorable, or unfavorable, effects on melanoma-associated gene expression. Here we present the logistics of using medaka to screen compounds, as well as, the development of a user-friendly NanoString data analysis pipeline to support feasibility of this novel TDS drug-screening strategy.
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Franchini P, Jones JC, Xiong P, Kneitz S, Gompert Z, Warren WC, Walter RB, Meyer A, Schartl M. Long-term experimental hybridisation results in the evolution of a new sex chromosome in swordtail fish. Nat Commun 2018; 9:5136. [PMID: 30510159 PMCID: PMC6277394 DOI: 10.1038/s41467-018-07648-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/13/2018] [Indexed: 01/13/2023] Open
Abstract
The remarkable diversity of sex determination mechanisms known in fish may be fuelled by exceptionally high rates of sex chromosome turnovers or transitions. However, the evolutionary causes and genomic mechanisms underlying this variation and instability are yet to be understood. Here we report on an over 30-year evolutionary experiment in which we tested the genomic consequences of hybridisation and selection between two Xiphophorus fish species with different sex chromosome systems. We find that introgression and imposing selection for pigmentation phenotypes results in the retention of an unexpectedly large maternally derived genomic region. During the hybridisation process, the sex-determining region of the X chromosome from one parental species was translocated to an autosome in the hybrids leading to the evolution of a new sex chromosome. Our results highlight the complexity of factors contributing to patterns observed in hybrid genomes, and we experimentally demonstrate that hybridisation can catalyze rapid evolution of a new sex chromosome. Fish have a high diversity of sex-determining systems, but the mechanisms responsible for this are not well understood. Here, Franchini et al. show how hybridization and backcrossing have led to the evolution of a new sex chromosome in swordtail fish during 30 years of experimental evolution.
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Regneri J, Klotz B, Wilde B, Kottler VA, Hausmann M, Kneitz S, Regensburger M, Maurus K, Götz R, Lu Y, Walter RB, Herpin A, Schartl M. Analysis of the putative tumor suppressor gene cdkn2ab in pigment cells and melanoma of Xiphophorus and medaka. Pigment Cell Melanoma Res 2018; 32:248-258. [PMID: 30117276 DOI: 10.1111/pcmr.12729] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 07/25/2018] [Accepted: 07/27/2018] [Indexed: 01/05/2023]
Abstract
In humans, the CDKN2A locus encodes two transcripts, INK4A and ARF. Inactivation of either one by mutations or epigenetic changes is a frequent signature of malignant melanoma and one of the most relevant entry points for melanomagenesis. To analyze whether cdkn2ab, the fish ortholog of CDKN2A, has a similar function as its human counterpart, we studied its action in fish models for human melanoma. Overexpression of cdkn2ab in a Xiphophorus melanoma cell line led to decreased proliferation and induction of a senescence-like phenotype, indicating a melanoma-suppressive function analogous to mammals. Coexpression of Xiphophorus cdkn2ab in medaka transgenic for the mitfa:xmrk melanoma-inducing gene resulted in full suppression of melanoma development, whereas CRISPR/Cas9 knockout of cdkn2ab resulted in strongly enhanced tumor growth. In summary, this provides the first functional evidence that cdkn2ab acts as a potent tumor suppressor gene in fish melanoma models.
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Klotz B, Kneitz S, Regensburger M, Hahn L, Dannemann M, Kelso J, Nickel B, Lu Y, Boswell W, Postlethwait J, Warren W, Kunz M, Walter RB, Schartl M. Expression signatures of early-stage and advanced medaka melanomas. Comp Biochem Physiol C Toxicol Pharmacol 2018; 208:20-28. [PMID: 29162497 PMCID: PMC5936653 DOI: 10.1016/j.cbpc.2017.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 01/07/2023]
Abstract
Melanoma is one of the most aggressive tumors with a very low survival rate once metastasized. The incidence of newly detected cases increases every year suggesting the necessity of development and application of innovative treatment strategies. Human melanoma develops from melanocytes localized in the epidermis of the skin to malignant tumors because of deregulated effectors influencing several molecular pathways. Despite many advances in describing the molecular changes accompanying melanoma formation, many critical and clinically relevant molecular features of the transformed pigment cells and the underlying mechanisms are largely unknown. To contribute to a better understanding of the molecular processes of melanoma formation, we use a transgenic medaka melanoma model that is well suited for the investigation of melanoma tumor development because fish and human melanocytes are both localized in the epidermis. The purpose of our study was to gain insights into melanoma development from the first steps of tumor formation up to melanoma progression and to identify gene expression patterns that will be useful for monitoring treatment effects in drug screening approaches. Comparing transcriptomes from juvenile fish at the tumor initiating stage with nevi and advanced melanoma of adults, we identified stage specific expression signatures and pathways that are characteristic for the development of medaka melanoma, and are also found in human malignancies.
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Boswell WT, Boswell M, Walter DJ, Navarro KL, Chang J, Lu Y, Savage MG, Shen J, Walter RB. Exposure to 4100K fluorescent light elicits sex specific transcriptional responses in Xiphophorus maculatus skin. Comp Biochem Physiol C Toxicol Pharmacol 2018; 208:96-104. [PMID: 28965926 PMCID: PMC5876067 DOI: 10.1016/j.cbpc.2017.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/14/2017] [Accepted: 09/20/2017] [Indexed: 02/06/2023]
Abstract
It has been reported that exposure to artificial light may affect oxygen intake, heart rate, absorption of vitamins and minerals, and behavioral responses in humans. We have reported specific gene expression responses in the skin of Xiphophorus fish after exposure to ultraviolet light (UV), as well as, both broad spectrum and narrow waveband visible light. In regard to fluorescent light (FL), we have shown that male X. maculatus exposed to 4100K FL (i.e. "cool white") rapidly suppress transcription of many genes involved with DNA replication and repair, chromosomal segregation, and cell cycle progression in skin. We have also detailed sex specific transcriptional responses of Xiphophorus skin after exposure to UVB. However, investigation of gender differences in global gene expression response after exposure to 4100K FL has not been reported, despite common use of this FL source for residential, commercial, and animal facility illumination. Here, we compare RNA-Seq results analyzed to assess changes in the global transcription profiles of female and male X. maculatus skin in response to 4100K FL exposure. Our results suggest 4100K FL exposure incites a sex-biased genetic response including up-modulation of inflammation in females and down modulation of DNA repair/replication in males. In addition, we identify clusters of genes that become oppositely modulated in males and females after FL exposure that are principally involved in cell death and cell proliferation.
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Gonzalez TJ, Lu Y, Boswell M, Boswell W, Medrano G, Walter S, Ellis S, Savage M, Varga ZM, Lawrence C, Sanders G, Walter RB. Fluorescent light exposure incites acute and prolonged immune responses in zebrafish (Danio rerio) skin. Comp Biochem Physiol C Toxicol Pharmacol 2018; 208:87-95. [PMID: 28965927 PMCID: PMC5876079 DOI: 10.1016/j.cbpc.2017.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/19/2017] [Accepted: 09/22/2017] [Indexed: 01/13/2023]
Abstract
Artificial light produces an emission spectrum that is considerably different than the solar spectrum. Artificial light has been shown to affect various behavior and physiological processes in vertebrates. However, there exists a paucity of data regarding the molecular genetic effects of artificial light exposure. Previous studies showed that one of the commonly used fluorescent light source (FL; 4100K or "cool white") can affect signaling pathways related to maintenance of circadian rhythm, cell cycle progression, chromosome segregation, and DNA repair/recombination in the skin of male Xiphophorus maculatus. These observations raise questions concerning the kinetics of the FL induced gene expression response, and which biological functions become modulated at various times after light exposure. To address these questions, we exposed zebrafish to 4100K FL and utilized RNA-Seq to assess gene expression changes in skin at various times (1 to 12h) after FL exposure. We found 4100K FL incites a robust early (1-2h) transcriptional response, followed by a more protracted late response (i.e., 4-12h). The early transcriptional response involves genes associated with cell migration/infiltration and cell proliferation as part of an overall increase in immune function and inflammation. The protracted late transcriptional response occurs within gene sets predicted to maintain and perpetuate the inflammatory response, as well as suppression of lipid, xenobiotic, and melatonin metabolism.
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Walter RB, Boswell M, Chang J, Boswell WT, Lu Y, Navarro K, Walter SM, Walter DJ, Salinas R, Savage M. Waveband specific transcriptional control of select genetic pathways in vertebrate skin (Xiphophorus maculatus). BMC Genomics 2018; 19:355. [PMID: 29747585 PMCID: PMC5946439 DOI: 10.1186/s12864-018-4735-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/26/2018] [Indexed: 01/08/2023] Open
Abstract
Background Evolution occurred exclusively under the full spectrum of sunlight. Conscription of narrow regions of the solar spectrum by specific photoreceptors suggests a common strategy for regulation of genetic pathways. Fluorescent light (FL) does not possess the complexity of the solar spectrum and has only been in service for about 60 years. If vertebrates evolved specific genetic responses regulated by light wavelengths representing the entire solar spectrum, there may be genetic consequences to reducing the spectral complexity of light. Results We utilized RNA-Seq to assess changes in the transcriptional profiles of Xiphophorus maculatus skin after exposure to FL (“cool white”), or narrow wavelength regions of light between 350 and 600 nm (i.e., 50 nm or 10 nm regions, herein termed “wavebands”). Exposure to each 50 nm waveband identified sets of genes representing discrete pathways that showed waveband specific transcriptional modulation. For example, 350–400 or 450–500 nm waveband exposures resulted in opposite regulation of gene sets marking necrosis and apoptosis (i.e., 350–400 nm; necrosis suppression, apoptosis activation, while 450–500 nm; apoptosis suppression, necrosis activation). Further investigation of specific transcriptional modulation employing successive 10 nm waveband exposures between 500 and 550 nm showed; (a) greater numbers of genes may be transcriptionally modulated after 10 nm exposures, than observed for 50 nm or FL exposures, (b) the 10 nm wavebands induced gene sets showing greater functional specificity than 50 nm or FL exposures, and (c) the genetic effects of FL are primarily due to 30 nm between 500 and 530 nm. Interestingly, many genetic pathways exhibited completely opposite transcriptional effects after different waveband exposures. For example, the epidermal growth factor (EGF) pathway exhibits transcriptional suppression after FL exposure, becomes highly active after 450–500 nm waveband exposure, and again, exhibits strong transcriptional suppression after exposure to the 520–530 nm waveband. Conclusions Collectively, these results suggest one may manipulate transcription of specific genetic pathways in skin by exposure of the intact animal to specific wavebands of light. In addition, we identify genes transcriptionally modulated in a predictable manner by specific waveband exposures. Such genes, and their regulatory elements, may represent valuable tools for genetic engineering and gene therapy protocols. Electronic supplementary material The online version of this article (10.1186/s12864-018-4735-5) contains supplementary material, which is available to authorized users.
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Warren WC, García-Pérez R, Xu S, Lampert KP, Chalopin D, Stöck M, Loewe L, Lu Y, Kuderna L, Minx P, Montague MJ, Tomlinson C, Hillier LW, Murphy DN, Wang J, Wang Z, Garcia CM, Thomas GWC, Volff JN, Farias F, Aken B, Walter RB, Pruitt KD, Marques-Bonet T, Hahn MW, Kneitz S, Lynch M, Schartl M. Clonal polymorphism and high heterozygosity in the celibate genome of the Amazon molly. Nat Ecol Evol 2018; 2:669-679. [PMID: 29434351 PMCID: PMC5866774 DOI: 10.1038/s41559-018-0473-y] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 01/09/2018] [Indexed: 12/21/2022]
Abstract
The extreme rarity of asexual vertebrates in nature is generally explained by genomic decay due to absence of meiotic recombination, thus leading to extinction of such lineages. We explore features of a vertebrate asexual genome, the Amazon molly, Poecilia formosa, and find few signs of genetic degeneration but unique genetic variability and ongoing evolution. We uncovered a substantial clonal polymorphism and, as a conserved feature from its interspecific hybrid origin, a 10-fold higher heterozygosity than in the sexual parental species. These characteristics seem to be a principal reason for the unpredicted fitness of this asexual vertebrate. Our data suggest that asexual vertebrate lineages are scarce not because they are at a disadvantage, but because the genomic combinations required to bypass meiosis and to make up a functioning hybrid genome are rarely met in nature.
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Warren WC, Kuderna L, Alexander A, Catchen J, Pérez-Silva JG, López-Otín C, Quesada V, Minx P, Tomlinson C, Montague MJ, Farias FHG, Walter RB, Marques-Bonet T, Glenn T, Kieran TJ, Wise SS, Wise JP, Waterhouse RM, Wise JP. The Novel Evolution of the Sperm Whale Genome. Genome Biol Evol 2017; 9:3260-3264. [PMID: 28985367 PMCID: PMC5726484 DOI: 10.1093/gbe/evx187] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2017] [Indexed: 01/21/2023] Open
Abstract
The sperm whale, made famous by Moby Dick, is one of the most fascinating of all ocean-dwelling species given their unique life history, novel physiological adaptations to hunting squid at extreme ocean depths, and their position as one of the earliest branching toothed whales (Odontoceti). We assembled the sperm whale (Physeter macrocephalus) genome and resequenced individuals from multiple ocean basins to identify new candidate genes for adaptation to an aquatic environment and infer demographic history. Genes crucial for skin integrity appeared to be particularly important in both the sperm whale and other cetaceans. We also find sperm whales experienced a steep population decline during the early Pleistocene epoch. These genomic data add new comparative insight into the evolution of whales.
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Kayser S, Krzykalla J, Elliott MA, Norsworthy K, Gonzales P, Hills RK, Baer MR, Ráčil Z, Mayer J, Novak J, Žák P, Szotkowski T, Grimwade D, Russell NH, Walter RB, Estey EH, Westermann J, Görner M, Benner A, Krämer A, Smith BD, Burnett AK, Thiede C, Röllig C, Ho AD, Ehninger G, Schlenk RF, Tallman MS, Levis MJ, Platzbecker U. Characteristics and outcome of patients with therapy-related acute promyelocytic leukemia front-line treated with or without arsenic trioxide. Leukemia 2017; 31:2347-2354. [PMID: 28322237 PMCID: PMC6037311 DOI: 10.1038/leu.2017.92] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 02/08/2023]
Abstract
Therapy-related acute promyelocytic leukemia (t-APL) is relatively rare, with limited data on outcome after treatment with arsenic trioxide (ATO) compared to standard intensive chemotherapy (CTX). We evaluated 103 adult t-APL patients undergoing treatment with all-trans retinoic acid (ATRA) alone (n=7) or in combination with ATO (n=24), CTX (n=53), or both (n=19). Complete remissions were achieved after induction therapy in 57% with ATRA, 100% with ATO/ATRA, 78% with CTX/ATRA, and 95% with CTX/ATO/ATRA. Early death rates were 43% for ATRA, 0% for ATO/ATRA, 12% for CTX/ATRA and 5% for CTX/ATO/ATRA. Three patients relapsed, two developed therapy-related acute myeloid leukemia and 13 died in remission including seven patients with recurrence of the prior malignancy. Median follow-up for survival was 3.7 years. None of the patients treated with ATRA alone survived beyond one year. Event-free survival was significantly higher after ATO-based therapy (95%, 95% CI, 82-99%) as compared to CTX/ATRA (78%, 95% CI, 64-87%; P=0.042), if deaths due to recurrence of the prior malignancy were censored. The estimated 2-year overall survival in intensively treated patients was 88% (95% CI, 80-93%) without difference according to treatment (P=0.47). ATO when added to ATRA or CTX/ATRA is feasible and leads to better outcomes as compared to CTX/ATRA in t-APL.
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MESH Headings
- Adolescent
- Adult
- Aged
- Aged, 80 and over
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Arsenic Trioxide
- Arsenicals/therapeutic use
- Female
- Humans
- Leukemia, Promyelocytic, Acute/drug therapy
- Leukemia, Promyelocytic, Acute/etiology
- Leukemia, Promyelocytic, Acute/genetics
- Male
- Middle Aged
- Neoplasms, Second Primary/drug therapy
- Neoplasms, Second Primary/etiology
- Neoplasms, Second Primary/genetics
- Oxides/therapeutic use
- Remission Induction
- Survival Analysis
- Treatment Outcome
- Young Adult
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Halpern AB, Othus M, Huebner EM, Buckley SA, Pogosova-Agadjanyan EL, Orlowski KF, Scott BL, Becker PS, Hendrie PC, Chen TL, Percival MEM, Estey EH, Stirewalt DL, Walter RB. Mitoxantrone, etoposide and cytarabine following epigenetic priming with decitabine in adults with relapsed/refractory acute myeloid leukemia or other high-grade myeloid neoplasms: a phase 1/2 study. Leukemia 2017; 31:2560-2567. [PMID: 28555084 PMCID: PMC5709258 DOI: 10.1038/leu.2017.165] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/06/2017] [Accepted: 05/22/2017] [Indexed: 12/29/2022]
Abstract
DNA methyltransferase inhibitors sensitize leukemia cells to chemotherapeutics. We therefore conducted a phase 1/2 study of mitoxantrone, etoposide, and cytarabine following “priming” with 5-10 days of decitabine (dec/MEC) in 52 adults (median age 55 [range: 19-72] years) with relapsed/refractory acute myeloid leukemia (AML) or other high-grade myeloid neoplasms. During dose escalation in cohorts of 6-12 patients, all dose levels were well-tolerated. As response rates appeared similar with 7 and 10-days of decitabine, a 7-day course was defined as the recommended phase 2 dose (RP2D). Among 46 patients treated at/above the RP2D, 10 (22%) achieved a complete remission (CR), 8 without measurable residual disease; five additional patients achieved CR with incomplete platelet recovery, for an overall response rate of 33%. Seven patients (15%) died within 28 days of treatment initiation. Infection/neutropenic fever, nausea, and mucositis were the most common adverse events. While the CR rate compared favorably to a matched historic control population (observed/expected CR ratio=1.77), CR rate and survival were similar to two contemporary salvage regimens used at our institution (G-CLAC and G-CLAM). Thus, while meeting the pre-specified efficacy goal, we found no evidence that dec/MEC is substantially better than other cytarabine-based regimens currently used for relapsed/refractory AML.
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Lu Y, Klimovich CM, Robeson KZ, Boswell W, Ríos-Cardenas O, Walter RB, Morris MR. Transcriptome assembly and candidate genes involved in nutritional programming in the swordtail fish Xiphophorus multilineatus. PeerJ 2017; 5:e3275. [PMID: 28480144 PMCID: PMC5417068 DOI: 10.7717/peerj.3275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Accepted: 04/04/2017] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Nutritional programming takes place in early development. Variation in the quality and/or quantity of nutrients in early development can influence long-term health and viability. However, little is known about the mechanisms of nutritional programming. The live-bearing fish Xiphophorus multilineatus has the potential to be a new model for understanding these mechanisms, given prior evidence of nutritional programming influencing behavior and juvenile growth rate. We tested the hypotheses that nutritional programming would influence behaviors involved in energy homeostasis as well gene expression in X. multilineatus. METHODS We first examined the influence of both juvenile environment (varied in nutrition and density) and adult environment (varied in nutrition) on behaviors involved in energy acquisition and energy expenditure in adult male X. multilineatus. We also compared the behavioral responses across the genetically influenced size classes of males. Males stop growing at sexual maturity, and the size classes of can be identified based on phenotypes (adult size and pigment patterns). To study the molecular signatures of nutritional programming, we assembled a de novo transcriptome for X. multilineatus using RNA from brain, liver, skin, testis and gonad tissues, and used RNA-Seq to profile gene expression in the brains of males reared in low quality (reduced food, increased density) and high quality (increased food, decreased density) juvenile environments. RESULTS We found that both the juvenile and adult environments influenced the energy intake behavior, while only the adult environment influenced energy expenditure. In addition, there were significant interactions between the genetically influenced size classes and the environments that influenced energy intake and energy expenditure, with males from one of the four size classes (Y-II) responding in the opposite direction as compared to the other males examined. When we compared the brains of males of the Y-II size class reared in a low quality juvenile environment to males from the same size class reared in high quality juvenile environment, 131 genes were differentially expressed, including metabolism and appetite master regulator agrp gene. DISCUSSION Our study provides evidence for nutritional programming in X. multilineatus, with variation across size classes of males in how juvenile environment and adult diet influences behaviors involved in energy homeostasis. In addition, we provide the first transcriptome of X. multilineatus, and identify a group of candidate genes involved in nutritional programming.
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Hourigan CS, Gale RP, Gormley NJ, Ossenkoppele GJ, Walter RB. Measurable residual disease testing in acute myeloid leukaemia. Leukemia 2017; 31:1482-1490. [PMID: 28386105 DOI: 10.1038/leu.2017.113] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/15/2017] [Accepted: 03/21/2017] [Indexed: 12/24/2022]
Abstract
There is considerable interest in developing techniques to detect and/or quantify remaining leukaemia cells termed measurable or, less precisely, minimal residual disease (MRD) in persons with acute myeloid leukaemia (AML) in complete remission defined by cytomorphological criteria. An important reason for AML MRD-testing is the possibility of estimating the likelihood (and timing) of leukaemia relapse. A perfect MRD-test would precisely quantify leukaemia cells biologically able and likely to cause leukaemia relapse within a defined interval. AML is genetically diverse and there is currently no uniform approach to detecting such cells. Several technologies focused on immune phenotype or cytogenetic and/or molecular abnormalities have been developed, each with advantages and disadvantages. Many studies report a positive MRD-test at diverse time points during AML therapy identifies persons with a higher risk of leukaemia relapse compared with those with a negative MRD-test even after adjusting for other prognostic and predictive variables. No MRD-test in AML has perfect sensitivity and specificity for relapse prediction at the cohort- or subject levels and there are substantial rates of false-positive and -negative tests. Despite these limitations, correlations between MRD-test results and relapse risk have generated interest in MRD-test result-directed therapy interventions. However, convincing proof that a specific intervention will reduce relapse risk in persons with a positive MRD-test is lacking and needs testing in randomized trials. Routine clinical use of MRD-testing requires further refinements and standardization/harmonization of assay platforms and results reporting. Such data are needed to determine whether results of MRD-testing can be used as a surrogate end point in AML therapy trials. This could make drug-testing more efficient and accelerate regulatory approvals. Although MRD-testing in AML has advanced substantially, much remains to be done.
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Song H, Lu Y, Qu Z, Mossine VV, Martin MB, Hou J, Cui J, Peculis BA, Mawhinney TP, Cheng J, Greenlief CM, Fritsche K, Schmidt FJ, Walter RB, Lubahn DB, Sun GY, Gu Z. Effects of aged garlic extract and FruArg on gene expression and signaling pathways in lipopolysaccharide-activated microglial cells. Sci Rep 2016; 6:35323. [PMID: 27734935 PMCID: PMC5062119 DOI: 10.1038/srep35323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/28/2016] [Indexed: 01/06/2023] Open
Abstract
Aged garlic extract (AGE) is widely used as a dietary supplement on account of its protective effects against oxidative stress and inflammation. But less is known about specific molecular targets of AGE and its bioactive components, including N-α-(1-deoxy-D-fructos-1-yl)-L-arginine (FruArg). Our recent study showed that both AGE and FruArg significantly attenuate lipopolysaccharide (LPS)-induced neuroinflammatory responses in BV-2 microglial cells. This study aims to unveil effects of AGE and FruArg on gene expression regulation in LPS stimulated BV-2 cells. Results showed that LPS treatment significantly altered mRNA levels from 2563 genes. AGE reversed 67% of the transcriptome alteration induced by LPS, whereas FruArg accounted for the protective effect by reversing expression levels of 55% of genes altered by LPS. Key pro-inflammatory canonical pathways induced by the LPS stimulation included toll-like receptor signaling, IL-6 signaling, and Nrf2-mediated oxidative stress pathway, along with elevated expression levels of genes, such as Il6, Cd14, Casp3, Nfkb1, Hmox1, and Tnf. These effects could be modulated by treatment with both AGE and FruArg. These findings suggests that AGE and FruArg are capable of alleviating oxidative stress and neuroinflammatory responses stimulated by LPS in BV-2 cells.
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Schartl M, Walter RB. Xiphophorus and Medaka Cancer Models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 916:531-52. [PMID: 27165369 DOI: 10.1007/978-3-319-30654-4_23] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Besides recently developed zebrafish cancer models, other fish species have been employed for many years as cancer models in laboratory studies. Two models, namely in Xiphophorus and medaka have proven useful in providing important clues to cancer etiology. Medaka is a complementary model to zebrafish in many areas of research since it offers similar resources and experimental tools. Xiphophorus provides the advantages of a natural ("evolutionary mutant") model with established genetics. Xiphophorus hybrids can develop spontaneous and radiation or carcinogen induced cancers. This chapter describes the tumor models in both species, which mainly focus on melanoma, and summarizes the main findings and future research directions.
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Kneitz S, Mishra RR, Chalopin D, Postlethwait J, Warren WC, Walter RB, Schartl M. Germ cell and tumor associated piRNAs in the medaka and Xiphophorus melanoma models. BMC Genomics 2016; 17:357. [PMID: 27183847 PMCID: PMC4869193 DOI: 10.1186/s12864-016-2697-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 05/06/2016] [Indexed: 11/10/2022] Open
Abstract
Background A growing number of studies report an abnormal expression of Piwi-interacting RNAs (piRNAs) and the piRNA processing enzyme Piwi in many cancers. Whether this finding is an epiphenomenon of the chaotic molecular biology of the fast dividing, neoplastically transformed cells or is functionally relevant to tumorigenesisis is difficult to discern at present. To better understand the role of piRNAs in cancer development small laboratory fish models can make a valuable contribution. However, little is known about piRNAs in somatic and neoplastic tissues of fish. Results To identify piRNA clusters that might be involved in melanoma pathogenesis, we use several transgenic lines of medaka, and platyfish/swordtail hybrids, which develop various types of melanoma. In these tumors Piwi, is expressed at different levels, depending on tumor type. To quantify piRNA levels, whole piRNA populations of testes and melanomas of different histotypes were sequenced. Because no reference piRNA cluster set for medaka or Xiphophorus was yet available we developed a software pipeline to detect piRNA clusters in our samples and clusters were selected that were enriched in one or more samples. We found several loci to be overexpressed or down-regulated in different melanoma subtypes as compared to hyperpigmented skin. Furthermore, cluster analysis revealed a clear distinction between testes, low-grade and high-grade malignant melanoma in medaka. Conclusions Our data imply that dysregulation of piRNA expression may be associated with development of melanoma. Our results also reinforce the importance of fish as a suitable model system to study the role of piRNAs in tumorigenesis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2697-z) contains supplementary material, which is available to authorized users.
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