Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
bioRxiv ; 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39149228

RESUMEN

Regenerating limbs retain their proximodistal (PD) positional identity following amputation. This positional identity is genetically encoded by PD patterning genes that instruct blastema cells to regenerate the appropriate PD limb segment. Retinoic acid (RA) is known to specify proximal limb identity, but how RA signaling levels are established in the blastema is unknown. Here, we show that RA breakdown via CYP26B1 is essential for determining RA signaling levels within blastemas. CYP26B1 inhibition molecularly reprograms distal blastemas into a more proximal identity, phenocopying the effects of administering excess RA. We identify Shox as an RA-responsive gene that is differentially expressed between proximally and distally amputated limbs. Ablation of Shox results in shortened limbs with proximal skeletal elements that fail to initiate endochondral ossification. These results suggest that PD positional identity is determined by RA degradation and RA-responsive genes that regulate PD skeletal element formation during limb regeneration.

2.
J Nat Prod ; 87(4): 798-809, 2024 04 26.
Artículo en Inglés | MEDLINE | ID: mdl-38412432

RESUMEN

Structural and functional studies of the carminomycin 4-O-methyltransferase DnrK are described, with an emphasis on interrogating the acceptor substrate scope of DnrK. Specifically, the evaluation of 100 structurally and functionally diverse natural products and natural product mimetics revealed an array of pharmacophores as productive DnrK substrates. Representative newly identified DnrK substrates from this study included anthracyclines, angucyclines, anthraquinone-fused enediynes, flavonoids, pyranonaphthoquinones, and polyketides. The ligand-bound structure of DnrK bound to a non-native fluorescent hydroxycoumarin acceptor, 4-methylumbelliferone, along with corresponding DnrK kinetic parameters for 4-methylumbelliferone and native acceptor carminomycin are also reported for the first time. The demonstrated unique permissivity of DnrK highlights the potential for DnrK as a new tool in future biocatalytic and/or strain engineering applications. In addition, the comparative bioactivity assessment (cancer cell line cytotoxicity, 4E-BP1 phosphorylation, and axolotl embryo tail regeneration) of a select set of DnrK substrates/products highlights the ability of anthracycline 4-O-methylation to dictate diverse functional outcomes.


Asunto(s)
Metiltransferasas , Metiltransferasas/metabolismo , Metiltransferasas/química , Estructura Molecular , Productos Biológicos/farmacología , Productos Biológicos/química , Humanos , Antraciclinas/química , Antraciclinas/farmacología , Especificidad por Sustrato
3.
bioRxiv ; 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38293091

RESUMEN

Research resources like transgenic animals and antibodies are the workhorses of biomedicine, enabling investigators to relatively easily study specific disease conditions. As key biological resources, transgenic animals and antibodies are often validated, maintained, and distributed from university based stock centers. As these centers heavily rely largely on grant funding, it is critical that they are cited by investigators so that usage can be tracked. However, unlike systems for tracking the impact of papers, the conventions and systems for tracking key resource usage and impact lag behind. Previous studies have shown that about 50% of the resources are not findable, making the studies they are supporting irreproducible, but also makes tracking resources difficult. The RRID project is filling this gap by working with journals and resource providers to improve citation practices and to track the usage of these key resources. Here, we reviewed 10 years of citation practices for five university based stock centers, characterizing each reference into two broad categories: findable (authors could use the RRID, stock number, or full name) and not findable (authors could use a nickname or a common name that is not unique to the resource). The data revealed that when stock centers asked their communities to cite resources by RRID, in addition to helping stock centers more easily track resource usage by increasing the number of RRID papers, authors shifted from citing resources predominantly by nickname (~50% of the time) to citing them by one of the findable categories (~85%) in a matter of several years. In the case of one stock center, the MMRRC, the improvement in findability is also associated with improvements in the adherence to NIH rigor criteria, as determined by a significant increase in the Rigor and Transparency Index for studies using MMRRC mice. From this data, it was not possible to determine whether outreach to authors or changes to stock center websites drove better citation practices, but findability of research resources and rigor adherence was improved.

4.
Front Cell Dev Biol ; 10: 814250, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35531102

RESUMEN

After amputation, axolotl salamanders can regenerate their limbs, but the degree to which limb regeneration recapitulates limb development remains unclear. One limitation in answering this question is our lack of knowledge about salamander limb development. Here, we address this question by studying expression patterns of genes important for limb patterning during axolotl salamander limb development and regeneration. We focus on the Wnt signaling pathway because it regulates multiple functions during tetrapod limb development, including limb bud initiation, outgrowth, patterning, and skeletal differentiation. We use fluorescence in situ hybridization to show the expression of Wnt ligands, Wnt receptors, and limb patterning genes in developing and regenerating limbs. Inhibition of Wnt ligand secretion permanently blocks limb bud outgrowth when treated early in limb development. Inhibiting Wnt signaling during limb outgrowth decreases the expression of critical signaling genes, including Fgf10, Fgf8, and Shh, leading to the reduced outgrowth of the limb. Patterns of gene expression are similar between developing and regenerating limbs. Inhibition of Wnt signaling during regeneration impacted patterning gene expression similarly. Overall, our findings suggest that limb development and regeneration utilize Wnt signaling similarly. It also provides new insights into the interaction of Wnt signaling with other signaling pathways during salamander limb development and regeneration.

5.
Dev Dyn ; 251(6): 913-921, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-33896069

RESUMEN

The laboratory axolotl (Ambystoma mexicanum) is widely used in biological research. Recent advancements in genetic and molecular toolkits are greatly accelerating the work using axolotl, especially in the area of tissue regeneration. At this juncture, there is a critical need to establish gene and transgenic nomenclature to ensure uniformity in axolotl research. Here, we propose guidelines for genetic nomenclature when working with the axolotl.


Asunto(s)
Ambystoma mexicanum , Cicatrización de Heridas , Ambystoma mexicanum/genética , Animales , Animales Modificados Genéticamente
6.
Curr Biol ; 31(22): 4923-4934.e5, 2021 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-34610275

RESUMEN

In most tetrapod vertebrates, limb skeletal progenitors condense with postaxial dominance. Posterior elements (such as ulna and fibula) appear prior to their anterior counterparts (radius and tibia), followed by digit-appearance order with continuing postaxial polarity. The only exceptions are urodele amphibians (salamanders), whose limb elements develop with preaxial polarity and who are also notable for their unique ability to regenerate complete limbs as adults. The mechanistic basis for this preaxial dominance has remained an enigma and has even been proposed to relate to the acquisition of novel genes involved in regeneration. However, recent fossil evidence suggests that preaxial polarity represents an ancestral rather than derived state. Here, we report that 5'Hoxd (Hoxd11-d13) gene deletion in mouse is atavistic and uncovers an underlying preaxial polarity in mammalian limb formation. We demonstrate this shift from postaxial to preaxial dominance in mouse results from excess Gli3 repressor (Gli3R) activity due to the loss of 5'Hoxd-Gli3 antagonism and is associated with cell-cycle changes promoting precocious cell-cycle exit in the anterior limb bud. We further show that Gli3 knockdown in axolotl results in a shift to postaxial dominant limb skeleton formation, as well as expanded paddle-shaped limb-bud morphology and ensuing polydactyly. Evolutionary changes in Gli3R activity level, which also played a key role in the fin-to-limb transition, appear to be fundamental to the shift from preaxial to postaxial polarity in formation of the tetrapod limb skeleton.


Asunto(s)
Extremidades , Esbozos de los Miembros , Animales , Evolución Biológica , Extremidades/anatomía & histología , Mamíferos , Ratones , Factores de Transcripción/genética , Urodelos/anatomía & histología
7.
Curr Microbiol ; 78(8): 3044-3057, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34125273

RESUMEN

Actinobacteria have proven themselves as the major producers of bioactive compounds with wide applications. In this study, 35 actinobacteria strains were isolated from soil samples collected from the Himalayan mountains region in Pakistan. The isolated strains were identified by polyphasic taxonomy and were prioritized based on biological and chemical screening to identify the strains with ability to produce inimitable metabolites. The biological screening included antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Salmonella enterica, Escherichia coli, Mycobacterium aurum, and Bacillus subtilis and anticancer activity using human cancer cell lines PC3 and A549. For chemical screening, methanolic extracts were investigated using TLC, HPLC-UV/MS. The actinobacteria strain PU-MM93 was selected for scale-up fermentation based on its unique chemical profile and cytotoxicity (50-60% growth inhibition) against PC3 and A549 cell lines. The scale-up fermentation of PU-MM93, followed by purification and structure elucidation of compounds revealed this strain as a promising producer of the cytotoxic anthracycline aranciamycin and aglycone SM-173-B along with the potent neuroprotective carboxamide oxachelin C. Other interesting metabolites produced include taurocholic acid as first report herein from microbial origin, pactamycate and cyclo(L-Pro-L-Leu). The study suggested exploring more bioactive microorganisms from the untapped Himalayan region in Pakistan, which can produce commercially significant compounds.


Asunto(s)
Actinobacteria , Antibacterianos/farmacología , Humanos , Metabolómica , Pruebas de Sensibilidad Microbiana , Mycobacteriaceae , Pakistán
8.
J Nat Prod ; 84(7): 1930-1940, 2021 07 23.
Artículo en Inglés | MEDLINE | ID: mdl-34170698

RESUMEN

Himalaquinones A-G, seven new anthraquinone-derived metabolites, were obtained from the Himalayan-based Streptomyces sp. PU-MM59. The chemical structures of the new compounds were identified based on cumulative analyses of HRESIMS and NMR spectra. Himalaquinones A-F were determined to be unique anthraquinones that contained unusual C-4a 3-methylbut-3-enoic acid aromatic substitutions, while himalaquinone G was identified as a new 5,6-dihydrodiol-bearing angucyclinone. Comparative bioactivity assessment (antimicrobial, cancer cell line cytotoxicity, impact on 4E-BP1 phosphorylation, and effect on axolotl embryo tail regeneration) revealed cytotoxic landomycin and saquayamycin analogues to inhibit 4E-BP1p and inhibit regeneration. In contrast, himalaquinone G, while also cytotoxic and a regeneration inhibitor, did not affect 4E-BP1p status at the doses tested. As such, this work implicates a unique mechanism for himalaquinone G and possibly other 5,6-dihydrodiol-bearing angucyclinones.


Asunto(s)
Antraquinonas/farmacología , Antineoplásicos/farmacología , Streptomyces/química , Ambystoma mexicanum , Aminoglicósidos/aislamiento & purificación , Aminoglicósidos/farmacología , Animales , Antraquinonas/aislamiento & purificación , Antineoplásicos/aislamiento & purificación , Línea Celular Tumoral , Humanos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Pakistán , Microbiología del Suelo
9.
Proc Natl Acad Sci U S A ; 118(15)2021 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-33827918

RESUMEN

Vertebrates harbor recognizably orthologous gene complements but vary 100-fold in genome size. How chromosomal organization scales with genome expansion is unclear, and how acute changes in gene regulation, as during axolotl limb regeneration, occur in the context of a vast genome has remained a riddle. Here, we describe the chromosome-scale assembly of the giant, 32 Gb axolotl genome. Hi-C contact data revealed the scaling properties of interphase and mitotic chromosome organization. Analysis of the assembly yielded understanding of the evolution of large, syntenic multigene clusters, including the Major Histocompatibility Complex (MHC) and the functional regulatory landscape of the Fibroblast Growth Factor 8 (Axfgf8) region. The axolotl serves as a primary model for studying successful regeneration.


Asunto(s)
Ambystoma mexicanum/genética , Evolución Molecular , Genoma , Animales , Cromosomas/genética , Sitios Genéticos , Transcriptoma
10.
Dev Dyn ; 250(6): 852-865, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33410213

RESUMEN

BACKGROUND: Histone deacetylases (HDACs) regulate transcriptional responses to injury stimuli that are critical for successful tissue regeneration. Previously we showed that HDAC inhibitor romidepsin potently inhibits axolotl tail regeneration when applied for only 1-minute postamputation (MPA). RESULTS: Here we tested CoCl2, a chemical that induces hypoxia and cellular stress, for potential to reverse romidepsin inhibition of tail regeneration. Partial rescue of regeneration was observed among embryos co-treated with romidepsin and CoCl2 for 1 MPA, however, extending the CoCl2 dosage window either inhibited regeneration (CoCl2 :0 to 30 MPA) or was lethal (CoCl2 :0 to 24 hours postamputation; HPA). CoCl2 :0 to 30 MPA caused tissue damage, tissue loss, and cell death at the distal tail tip, while CoCl2 treatment of non-amputated embryos or CoCl2 :60 to 90 MPA treatment after re-epithelialization did not inhibit tail regeneration. CoCl2 -romidepsin:1 MPA treatment partially restored expression of transcription factors that are typical of appendage regeneration, while CoCl2 :0 to 30 MPA significantly increased expression of genes associated with cell stress and inflammation. Additional experiments showed that CoCl2 :0 to 1 MPA and CoCl2 :0 to 30 MPA significantly increased levels of glutathione and reactive oxygen species, respectively. CONCLUSION: Our study identifies a temporal window from tail amputation to re-epithelialization, within which injury activated cells are highly sensitive to CoCl2 perturbation of redox homeostasis.


Asunto(s)
Ambystoma mexicanum/fisiología , Cobalto/farmacología , Regeneración/efectos de los fármacos , Cola (estructura animal)/fisiología , Amputación Quirúrgica , Animales , Muerte Celular/efectos de los fármacos , Depsipéptidos/farmacología , Inhibidores de Histona Desacetilasas/farmacología , Cola (estructura animal)/efectos de los fármacos , Factores de Tiempo
11.
Front Cell Dev Biol ; 9: 767377, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35036404

RESUMEN

New patterns of gene expression are enacted and regulated during tissue regeneration. Histone deacetylases (HDACs) regulate gene expression by removing acetylated lysine residues from histones and proteins that function directly or indirectly in transcriptional regulation. Previously we showed that romidepsin, an FDA-approved HDAC inhibitor, potently blocks axolotl embryo tail regeneration by altering initial transcriptional responses to injury. Here, we report on the concentration-dependent effect of romidepsin on transcription and regeneration outcome, introducing an experimental and conceptual framework for investigating small molecule mechanisms of action. A range of romidepsin concentrations (0-10 µM) were administered from 0 to 6 or 0 to 12 h post amputation (HPA) and distal tail tip tissue was collected for gene expression analysis. Above a threshold concentration, romidepsin potently inhibited regeneration. Sigmoidal and biphasic transcription response curve modeling identified genes with inflection points aligning to the threshold concentration defining regenerative failure verses success. Regeneration inhibitory concentrations of romidepsin increased and decreased the expression of key genes. Genes that associate with oxidative stress, negative regulation of cell signaling, negative regulation of cell cycle progression, and cellular differentiation were increased, while genes that are typically up-regulated during appendage regeneration were decreased, including genes expressed by fibroblast-like progenitor cells. Using single-nuclei RNA-Seq at 6 HPA, we found that key genes were altered by romidepin in the same direction across multiple cell types. Our results implicate HDAC activity as a transcriptional mechanism that operates across cell types to regulate the alternative expression of genes that associate with regenerative success versus failure outcomes.

12.
J Exp Zool B Mol Dev Evol ; 336(2): 129-144, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-31584252

RESUMEN

Among tetrapods, only salamanders can regenerate their limbs and tails throughout life. This amazing regenerative ability has attracted the attention of scientists for hundreds of years. Now that large, salamander genomes are beginning to be sequenced for the first time, omics tools and approaches can be used to integrate new perspectives into the study of tissue regeneration. Here we argue the need to move beyond the primary salamander models to investigate regeneration in other species. Salamanders at first glance come across as a phylogenetically conservative group that has not diverged greatly from their ancestors. While salamanders do present ancestral characteristics of basal tetrapods, including the ability to regenerate limbs, data from fossils and data from studies that have tested for species differences suggest there may be considerable variation in how salamanders develop and regenerate their limbs. We review the case for expanded studies of salamander tissue regeneration and identify questions and approaches that are most likely to reveal commonalities and differences in regeneration among species. We also address challenges that confront such an initiative, some of which are regulatory and not scientific. The time is right to gain evolutionary perspective about mechanisms of tissue regeneration from comparative studies of salamander species.


Asunto(s)
Extremidades/fisiología , Regeneración/fisiología , Urodelos/fisiología , Animales , Regeneración/genética , Especificidad de la Especie , Urodelos/genética
13.
Dev Dyn ; 250(6): 807-821, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32864847

RESUMEN

BACKGROUND: Vertebrate eye formation requires coordinated inductive interactions between different embryonic tissue layers, first described in amphibians. A network of transcription factors and signaling molecules controls these steps, with mutations causing severe ocular, neuronal, and craniofacial defects. In eyeless mutant axolotls, eye morphogenesis arrests at the optic vesicle stage, before lens induction, and development of ventral forebrain structures is disrupted. RESULTS: We identified a 5-bp deletion in the rax (retina and anterior neural fold homeobox) gene, which was tightly linked to the recessive eyeless (e) axolotl locus in an F2 cross. This frameshift mutation, in exon 2, truncates RAX protein within the homeodomain (P154fs35X). Quantitative RNA analysis shows that mutant and wild-type rax transcripts are equally abundant in E/e embryos. Translation appears to initiate from dual start codons, via leaky ribosome scanning, a conserved feature among gnathostome RAX proteins. Previous data show rax is expressed in the optic vesicle and diencephalon, deeply conserved among metazoans, and required for eye formation in other species. CONCLUSION: The eyeless axolotl mutation is a null allele in the rax homeobox gene, with primary defects in neural ectoderm, including the retinal and hypothalamic primordia.


Asunto(s)
Ambystoma mexicanum/genética , Proteínas del Ojo/genética , Proteínas de Homeodominio/genética , Mutación , Factores de Transcripción/genética , Ambystoma mexicanum/metabolismo , Animales , Desarrollo Embrionario/genética , Proteínas del Ojo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Factores de Transcripción/metabolismo
14.
Dev Dyn ; 250(6): 822-837, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33001517

RESUMEN

BACKGROUND: Recent efforts to assemble and analyze the Ambystoma mexicanum genome have dramatically improved the potential to develop molecular tools and pursue genome-wide analyses of genetic variation. RESULTS: To better resolve the distribution and origins of genetic variation with A mexicanum, we compared DNA sequence data for two laboratory A mexicanum and one A tigrinum to identify 702 million high confidence polymorphisms distributed across the 32 Gb genome. While the wild-caught A tigrinum was generally more polymorphic in a genome-wide sense, several multi-megabase regions were identified from A mexicanum genomes that were actually more polymorphic than A tigrinum. Analysis of polymorphism and repeat content reveals that these regions likely originated from the intentional hybridization of A mexicanum and A tigrinum that was used to introduce the albino mutation into laboratory stocks. CONCLUSIONS: Our findings show that axolotl genomes are variable with respect to introgressed DNA from a highly polymorphic species. It seems likely that other divergent regions will be discovered with additional sequencing of A mexicanum. This has practical implications for designing molecular probes and suggests a need to study A mexicanum phenotypic variation and genome evolution across the tiger salamander clade.


Asunto(s)
Ambystoma mexicanum/genética , Variación Biológica Poblacional , Genoma , Polimorfismo de Nucleótido Simple , Animales , Mutación
15.
Data Brief ; 29: 105256, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32123704

RESUMEN

The amphibian order Caudata, contains several important model species for biological research. However, there is need to generate transcriptome data from representative species of the primary salamander families. Here we describe a de novo reference transcriptome for a terrestrial salamander, Bolitoglossa vallecula (Caudata: Plethodontidae). We employed paired-end (PE) illumina RNA sequencing to assemble a de novo reference transcriptome for B. vallecula. Assembled transcripts were compared against sequences from other vertebrate taxa to identify orthologous genes, and compared to the transcriptome of a close plethodontid relative (Bolitoglossa ramosi) to identify commonly expressed genes in the skin. This dataset should be useful to future comparative studies aimed at understanding important biological process, such as immunity, wound healing, and the production of antimicrobial compounds.

16.
Chembiochem ; 21(7): 952-957, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-31621997

RESUMEN

Herein we describe the ability of the permissive glycosyltransferase (GT) OleD Loki to convert a diverse set of >15 histone deacetylase (HDAC) inhibitors (HDACis) into their corresponding hydroxamate glycosyl esters. Representative glycosyl esters were subsequently evaluated in assays for cancer cell line cytotoxicity, chemical and enzymatic stability, and axolotl embryo tail regeneration. Computational substrate docking models were predictive of enzyme-catalyzed turnover and suggest certain HDACis may form unproductive, potentially inhibitory, complexes with GTs.


Asunto(s)
Proteínas Bacterianas/metabolismo , Glucosiltransferasas/metabolismo , Ácidos Hidroxámicos/metabolismo , Proteínas Bacterianas/antagonistas & inhibidores , Sitios de Unión , Biocatálisis , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Glucosiltransferasas/antagonistas & inhibidores , Glicosilación , Inhibidores de Histona Desacetilasas/química , Inhibidores de Histona Desacetilasas/metabolismo , Inhibidores de Histona Desacetilasas/farmacología , Humanos , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/farmacología , Simulación del Acoplamiento Molecular , Especificidad por Sustrato
17.
J Nat Prod ; 82(12): 3469-3476, 2019 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-31833370

RESUMEN

We report the isolation and characterization of three new nybomycins (nybomycins B-D, 1-3) and six known compounds (nybomycin, 4; deoxynyboquinone, 5; α-rubromycin, 6; ß-rubromycin, 7; γ-rubromycin, 8; and [2α(1E,3E),4ß]-2-(1,3-pentadienyl)-4-piperidinol, 9) from the Rock Creek (McCreary County, KY) underground coal mine acid reclamation site isolate Streptomyces sp. AD-3-6. Nybomycin D (3) and deoxynyboquinone (5) displayed moderate (3) to potent (5) cancer cell line cytotoxicity and displayed weak to moderate anti-Gram-(+) bacterial activity, whereas rubromycins 6-8 displayed little to no cancer cell line cytotoxicity but moderate to potent anti-Gram-(+) bacterial and antifungal activity. Assessment of the impact of 3 or 5 cancer cell line treatment on 4E-BP1 phosphorylation, a predictive marker of ROS-mediated control of cap-dependent translation, also revealed deoxynyboquinone (5)-mediated downstream inhibition of 4E-BP1p. Evaluation of 1-9 in a recently established axolotl embryo tail regeneration assay also highlighted the prototypical telomerase inhibitor γ-rubromycin (8) as a new inhibitor of tail regeneration. Cumulatively, this work highlights an alternative nybomycin production strain, a small set of new nybomycin metabolites, and previously unknown functions of rubromycins (antifungal activity and inhibition of tail regeneration) and also provides a basis for revision of the previously proposed nybomycin biosynthetic pathway.


Asunto(s)
Streptomyces/metabolismo , Antibacterianos/química , Antibacterianos/farmacología , Antifúngicos/química , Antifúngicos/farmacología , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Bacterias Grampositivas/efectos de los fármacos , Humanos , Estructura Molecular , Quinolonas/química , Quinolonas/metabolismo , Quinolonas/farmacología , Análisis Espectral/métodos
18.
Chem Sci ; 10(32): 7641-7648, 2019 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-31583069

RESUMEN

A divergent modular strategy for the enantioselective total synthesis of 12 naturally-occurring griseusin type pyranonaphthoquinones and 8 structurally-similar analogues is described. Key synthetic highlights include Cu-catalyzed enantioselective boration-hydroxylation and hydroxyl-directed C-H olefination to afford the central pharmacophore followed by epoxidation-cyclization and maturation via diastereoselective reduction and regioselective acetylation. Structural revision of griseusin D and absolute structural assignment of 2a,8a-epoxy-epi-4'-deacetyl griseusin B are also reported. Subsequent mechanistic studies establish, for the first time, griseusins as potent inhibitors of peroxiredoxin 1 (Prx1) and glutaredoxin 3 (Grx3). Biological evaluation, including comparative cancer cell line cytotoxicity and axolotl embryo tail inhibition studies, highlights the potential of griseusins as potent molecular probes and/or early stage leads in cancer and regenerative biology.

19.
Sci Rep ; 9(1): 6751, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31043677

RESUMEN

Tissue regeneration is associated with complex changes in gene expression and post-translational modifications of proteins, including transcription factors and histones that comprise chromatin. We tested 172 compounds designed to target epigenetic mechanisms in an axolotl (Ambystoma mexicanum) embryo tail regeneration assay. A relatively large number of compounds (N = 55) inhibited tail regeneration, including 18 histone deacetylase inhibitors (HDACi). In particular, romidepsin, an FDA-approved anticancer drug, potently inhibited tail regeneration when embryos were treated continuously for 7 days. Additional experiments revealed that romidepsin acted within a very narrow, post-injury window. Romidepsin treatment for only 1-minute post amputation inhibited regeneration through the first 7 days, however after this time, regeneration commenced with variable outgrowth of tailfin tissue and abnormal patterning. Microarray analysis showed that romidepsin altered early, transcriptional responses at 3 and 6-hour post-amputation, especially targeting genes that are implicated in tumor cell death, as well as genes that function in the regulation of transcription, cell differentiation, cell proliferation, pattern specification, and tissue morphogenesis. Our results show that HDAC activity is required at the time of tail amputation to regulate the initial transcriptional response to injury and regeneration.


Asunto(s)
Ambystoma mexicanum/fisiología , Histona Desacetilasas/metabolismo , Regeneración , Cola (estructura animal)/fisiología , Transcripción Genética , Animales , Biología Computacional/métodos , Epigenómica , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Regeneración/efectos de los fármacos
20.
J Nat Prod ; 82(6): 1686-1693, 2019 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-31117525

RESUMEN

The structures and bioactivities of three unprecedented fused 5-hydroxyquinoxaline/alpha-keto acid amino acid metabolites (baraphenazines A-C, 1-3), two unique diastaphenazine-type metabolites (baraphenazines D and E, 4 and 5) and two new phenazinolin-type (baraphenazines F and G, 6 and 7) metabolites from the Himalayan isolate Streptomyces sp. PU-10A are reported. This study highlights the first reported bacterial strain capable of producing diastaphenazine-type, phenazinolin-type, and izumiphenazine A-type metabolites and presents a unique opportunity for the future biosynthetic interrogation of late-stage phenazine-based metabolite maturation.


Asunto(s)
Antibacterianos/metabolismo , Fenazinas/metabolismo , Quinoxalinas/química , Streptomyces/química , Antibacterianos/química , Estructura Molecular , Fenazinas/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA