RESUMO
Herpes simplex virus type 1 (HSV-1) is an important human pathogen with neurotropism. Following lytic infection in mucosal or skin epithelium, life-long latency is established mainly in sensory neurons, which can periodically reactivate by stress, leading to recurrent disease and virus transmission. During the virus's productive infection, the tegument protein VP16, a component of HSV-1 virion, is physically associated with two cellular factors, host cell factor-1 (HCF-1), and POU domain protein Oct-1, to construct the VP16-induced complex, which is essential to stimulate immediate early (IE)-gene transcription as well as initiate the lytic programme. Apart from HCF-1 and Oct-1, VP16 also associates with a series of other host factors, making a VP16-induced regulatory switch to either activate or inactivate virus gene transcription. In addition, VP16 has effects on distinct signalling pathways via binding to various host molecules that are essentially related to innate immune responses, RNA polymerases, molecular chaperones, and virus infection-induced host shutoff. VP16 also functionally compensates for given host factors, such as PPAR-γ and ß-catenin. In this review, we provide an overview of the updated insights on the interplay between VP16 and the host factors that coordinate virus infection.
Assuntos
Herpesvirus Humano 1 , Fatores de Transcrição , Humanos , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Herpesvirus Humano 1/metabolismo , Proteína Vmw65 do Vírus do Herpes Simples/química , Proteína Vmw65 do Vírus do Herpes Simples/metabolismo , Fator C1 de Célula Hospedeira , Etoposídeo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismoRESUMO
Herpes Simplex Virus 1 (HSV-1) is a human pathogen that has the ability to establish a lifelong infection in the host. During latency, HSV-1 genomes are chromatinized and are abundantly associated with histones in sensory neurons, yet the mechanisms that govern the latent-lytic transition remain unclear. We hypothesize that the latent-lytic switch is controlled by CTCF insulators, positioned within the HSV-1 latent genome. CTCF insulators, together with the cohesin complex, have the ability to establish and maintain chromtin loops that allow distance separated gene regions to be spatially oriented for transcriptional control. In this current study, we demonstrated that the cohesin subunit Rad21 was recruited to latent HSV-1 genomes near four of the CTCF insulators during latency. We showed that the CTCF insulator known as CTRS1/2, positioned downstream from the essential transactivating IE region of ICP4 was only enriched in Rad21 prior to but not during latency, suggesting that the CTRS1/2 insulator is not required for the maintenance of latency. Further, deletion of the CTRL2 insulator, positioned downstream from the LAT enhancer, resulted in a loss of Rad21 enrichment at insulators flanking the ICP4 region at early times post-infection in mice ganglia, suggesting that these insulators are interdependent. Finally, deletion of the CTRL2 insulator resulted in a loss of Rad21 enrichment at the CTRL2 insulator in a cell-type specific manner, and this loss of Rad21 enrichment was correlated to decreased LAT expression, suggesting that Rad21 recruitment to viral genomes is important for efficient gene expression.ImportanceCTCF insulators are important for transcriptional control and increasing evidence suggests that that CTCF insulators, together with the cohesin complex, regulate viral transcription in DNA viruses. The CTCF-cohesin interaction is important for the formation of chromatin loops, structures that orient distance separated elements in close spatial proximity for transcriptional control. Herpes Simplex Virus 1 (HSV-1) has seven putative CTCF insulators that flank the LAT and the IE, indicating that CTCF insulators play a role in the transition from latency to reactivation. Contributions from the work presented here include the finding that CTCF insulators in HSV-1 genomes are differentially enriched in the cohesin subunit Rad21, suggesting that CTCF-cohesin interactions could be establishing and anchoring chromatin loop structures to control viral transcription.
RESUMO
The regulatory functions of 10 individual viral microRNAs (miRNAs) that are abundantly expressed from the herpes simplex virus 1 (HSV-1) latency-associated transcript (LAT) region remain largely unknown. Here, we focus on HSV-1 miRNA miR-H8, which is within the LAT 3p exon, antisense to the first intron of ICP0, and has previously been shown to target a host glycosylphosphatidylinositol (GPI)-anchoring pathway. However, the functions of this miRNA have not been assessed in the context of the viral genome during infection. Therefore, we constructed a recombinant virus lacking miR-H8 (17dmiR-H8) and compared it to the parental wild-type and rescue viruses to characterize phenotypic differences. In rabbit skin cells, 17dmiR-H8 exhibited only subtle reductions in viral yields. In contrast, we found significant decreases in both viral yields (8-fold) and DNA replication (9.9-fold) in murine neuroblastoma cells, while 17dmiR-H8 exhibited a 3.6-fold increase in DNA replication in differentiated human neuronal cells (Lund human mesencephalic [LUHMES] cells). These cell culture phenotypes suggested potential host- and/or neuron-specific roles for miR-H8 in acute viral replication. To assess whether miR-H8 plays a role in HSV latency or reactivation, we used a human in vitro reactivation model as well as mouse and rabbit reactivation models. In the LUHMES cell-induced reactivation model, there was no difference in viral yields at 48 h postreactivation. In the murine dorsal root ganglion explant and rabbit ocular adrenergic reactivation models, the deletion of miR-H8 had no detectable effect on genome loads during latency or reactivation. These results indicate that miR-H8 is dispensable for the establishment of HSV-1 latency and reactivation.IMPORTANCE Herpesviruses have a remarkable ability to sustain lifelong infections by evading host immune responses, establishing a latent reservoir, and maintaining the ability to reactivate the lytic cascade to transmit the virus to the next host. The HSV-1 latency-associated transcript region is known to regulate many aspects of HSV-1 latency and reactivation, although the mechanisms for these functions remain unknown. To this end, we characterize an HSV-1 recombinant containing a deletion of a LAT-encoded miRNA, miR-H8, and demonstrate that it plays no detectable role in the establishment of latency or reactivation in differentiated human neurons (LUHMES cells) and mouse and rabbit models. Therefore, this study allows us to exclude miR-H8 from phenotypes previously attributed to the LAT region. Elucidating the genetic elements of HSV-1 responsible for establishment, maintenance, and reactivation from latency may lead to novel strategies for combating persistent herpesvirus infections.
Assuntos
Herpes Simples/virologia , Herpesvirus Humano 1/fisiologia , MicroRNAs/metabolismo , Neurônios/virologia , Ativação Viral , Latência Viral , Animais , Linhagem Celular Tumoral , Feminino , Gânglios Espinais/virologia , Regulação Viral da Expressão Gênica , Células HEK293 , Humanos , Camundongos , Neurônios/patologia , RNA Viral , CoelhosRESUMO
During all stages of infection, herpes simplex virus 1 (HSV-1) expresses viral microRNAs (miRNAs). There are at least 20 confirmed HSV-1 miRNAs, yet the roles of individual miRNAs in the context of viral infection remain largely uncharacterized. We constructed a recombinant virus lacking the sequences for miR-H1-5p and miR-H6-3p (17dmiR-H1/H6). The seed sequences for these miRNAs are antisense to each other and are transcribed from divergent noncoding RNAs in the latency-associated transcript (LAT) promoter region. Comparing phenotypes exhibited by the recombinant virus lacking these miRNAs to the wild type (17syn+), we found that during acute infection in cell culture, 17dmiR-H1/H6 exhibited a modest increase in viral yields. Analysis of pathogenesis in the mouse following footpad infection revealed a slight increase in virulence for 17dmiR-H1/H6 but no significant difference in the establishment or maintenance of latency. Strikingly, explant of latently infected dorsal root ganglia revealed a decreased and delayed reactivation phenotype. Further, 17dmiR-H1/H6 was severely impaired in epinephrine-induced reactivation in the rabbit ocular model. Finally, we demonstrated that deletion of miR-H1/H6 increased the accumulation of the LAT as well as several of the LAT region miRNAs. These results suggest that miR-H1/H6 plays an important role in facilitating efficient reactivation from latency.IMPORTANCE While HSV antivirals reduce the severity and duration of clinical disease in some individuals, there is no vaccine or cure. Therefore, understanding the mechanisms regulating latency and reactivation as a potential to elucidate targets for better therapeutics is important. There are at least 20 confirmed HSV-1 miRNAs, yet the roles of individual miRNAs in the context of viral infection remain largely uncharacterized. The present study focuses on two of the miRNAs (miR-H1/H6) that are encoded within the latency-associated transcript (LAT) region, a portion of the genome that has been associated with efficient reactivation. Here, we demonstrate that the deletion of the seed sequences of these miRNAs results in a severe reduction in reactivation of HSV-1 in the mouse and rabbit models. These results suggest a linkage between these miRNAs and reactivation.
Assuntos
Gânglios Espinais/metabolismo , Herpes Simples/metabolismo , Herpesvirus Humano 1/fisiologia , MicroRNAs/metabolismo , RNA Viral/metabolismo , Ativação Viral , Latência Viral , Animais , Gânglios Espinais/virologia , Células HEK293 , Herpes Simples/genética , Humanos , Camundongos , MicroRNAs/genética , RNA Viral/genética , CoelhosRESUMO
The cellular insulator protein CTCF plays a role in herpes simplex virus 1 (HSV-1) latency through the establishment and regulation of chromatin boundaries. We previously found that the CTRL2 regulatory element downstream from the latency-associated transcript (LAT) enhancer was bound by CTCF during latency and underwent CTCF eviction at early times postreactivation in mice latently infected with 17syn+ virus. We also showed that CTRL2 was a functional enhancer-blocking insulator in both epithelial and neuronal cell lines. We hypothesized that CTRL2 played a direct role in silencing lytic gene expression during the establishment of HSV-1 latency. To test this hypothesis, we used a recombinant virus with a 135-bp deletion spanning only the core CTRL2 insulator domain (ΔCTRL2) in the 17syn+ background. Deletion of CTRL2 resulted in restricted viral replication in epithelial cells but not neuronal cells. Following ocular infection, mouse survival decreased in the ΔCTRL2-infected cohort, and we found a significant decrease in the number of viral genomes in mouse trigeminal ganglia (TG) infected with ΔCTRL2, indicating that the CTRL2 insulator was required for the efficient establishment of latency. Immediate early (IE) gene expression significantly increased in the number of ganglia infected with ΔCTRL2 by 31 days postinfection relative to the level with 17syn+ infection, indicating that deletion of the CTRL2 insulator disrupted the organization of chromatin domains during HSV-1 latency. Finally, chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) analyses of TG from ΔCTRL2-infected mice confirmed that the distribution of the repressive H3K27me3 (histone H3 trimethylated at K27) mark on the ΔCTRL2 recombinant genomes was altered compared to that of the wild type, indicating that the CTRL2 site modulates the repression of IE genes during latency.IMPORTANCE It is becoming increasingly clear that chromatin insulators play a key role in the transcriptional control of DNA viruses. The gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) utilize chromatin insulators to order protein recruitment and dictate the formation of three-dimensional DNA loops that spatially control transcription and latency. The contribution of chromatin insulators in alphaherpesvirus transcriptional control is less well understood. The work presented here begins to bridge that gap in knowledge by showing how one insulator site in HSV-1 modulates lytic gene transcription and heterochromatin deposition as the HSV-1 genome establishes latency.
Assuntos
Fator de Ligação a CCCTC/metabolismo , Herpesvirus Humano 1/metabolismo , Heterocromatina/metabolismo , Latência Viral/fisiologia , Animais , Fator de Ligação a CCCTC/genética , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Imunoprecipitação da Cromatina , Modelos Animais de Doenças , Epigenômica , Infecções Oculares/virologia , Gânglios/virologia , Regulação Viral da Expressão Gênica , Inativação Gênica , Genoma Viral , Herpes Simples/virologia , Herpesvirus Humano 1/genética , Herpesvirus Humano 4/fisiologia , Herpesvirus Humano 8/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Ativação Viral , Replicação ViralRESUMO
There are seven conserved CTCF binding domains in the herpes simplex virus 1 (HSV-1) genome. These binding sites individually flank the latency-associated transcript (LAT) and the immediate early (IE) gene regions, suggesting that CTCF insulators differentially control transcriptional domains in HSV-1 latency. In this work, we show that two CTCF binding motifs in HSV-1 display enhancer blocking in a cell-type-specific manner. We found that CTCF binding to the latent HSV-1 genome was LAT dependent and that the quantity of bound CTCF was site specific. Following reactivation, CTCF eviction was dynamic, suggesting that each CTCF site was independently regulated. We explored whether CTCF sites recruit the polycomb-repressive complex 2 (PRC2) to establish repressive domains through a CTCF-Suz12 interaction and found that Suz12 colocalized to the CTCF insulators flanking the ICP0 and ICP4 regions and, conversely, was removed at early times postreactivation. Collectively, these data support the idea that CTCF sites in HSV-1 are independently regulated and may contribute to lytic-latent HSV-1 control in a site-specific manner.IMPORTANCE The role of chromatin insulators in DNA viruses is an area of interest. It has been shown in several beta- and gammaherpesviruses that insulators likely control the lytic transcriptional profile through protein recruitment and through the formation of three-dimensional (3D) chromatin loops. The ability of insulators to regulate alphaherpesviruses has been understudied to date. The alphaherpesvirus HSV-1 has seven conserved insulator binding motifs that flank regions of the genome known to contribute to the establishment of latency. Our work presented here contributes to the understanding of how insulators control transcription of HSV-1.
Assuntos
Fator de Ligação a CCCTC/metabolismo , DNA Viral/metabolismo , Genoma Viral , Herpes Simples/metabolismo , Herpesvirus Humano 1/fisiologia , Elementos Isolantes , Motivos de Nucleotídeos , Latência Viral/fisiologia , Animais , Fator de Ligação a CCCTC/genética , DNA Viral/genética , Feminino , Herpes Simples/genética , Herpes Simples/patologia , Camundongos , Camundongos Endogâmicos BALB C , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismoRESUMO
During herpes simplex virus (HSV) latency, most viral genes are silenced, with the exception of one region of the genome encoding the latency-associated transcript (LAT). This long noncoding RNA was originally described as having a role in enhancing HSV-1 reactivation. However, subsequent evidence showing that the LAT blocked apoptosis and promoted efficient establishment of latency suggested that its effects on reactivation were secondary to establishment. Here, we utilized an adeno-associated virus (AAV) vector to deliver a LAT-targeting hammerhead ribozyme to HSV-1-infected neurons of rabbits after the establishment of HSV-1 latency. The rabbits were then induced to reactivate latent HSV-1. Using this model, we show that decreasing LAT levels in neurons following the establishment of latency reduced the ability of the virus to reactivate. This demonstrates that the HSV-1 LAT RNA has a role in reactivation that is independent of its function in establishment of latency. In addition, these results suggest the potential of AAV vectors expressing LAT-targeting ribozymes as a potential therapy for recurrent HSV disease such as herpes stromal keratitis, a leading cause of infectious blindness.IMPORTANCE Herpes simplex virus (HSV) establishes a lifelong infection and remains dormant (latent) in our nerve cells. Occasionally HSV reactivates to cause disease, with HSV-1 typically causing cold sores whereas HSV-2 is the most common cause of genital herpes. The details of how HSV reactivates are largely unknown. Most of HSV's genes are silent during latency, with the exception of RNAs made from the latency-associated transcript (LAT) region. While viruses that make less LAT do not reactivate efficiently, these viruses also do not establish latency as efficiently. Here we deliver a ribozyme that can degrade the LAT to the nerve cells of latently infected rabbits using a gene therapy vector. We show that this treatment blocks reactivation in the majority of the rabbits. This work shows that the LAT RNA is important for reactivation and suggests the potential of this treatment as a therapy for treating HSV infections.
Assuntos
Regulação Viral da Expressão Gênica , Herpesvirus Humano 1/fisiologia , RNA Longo não Codificante/metabolismo , RNA Viral/metabolismo , Ativação Viral , Latência Viral , Animais , Células Cultivadas , Dependovirus/genética , Vetores Genéticos , Herpesvirus Humano 1/genética , Neurônios/virologia , RNA Catalítico/genética , RNA Catalítico/metabolismo , RNA Longo não Codificante/genética , RNA Viral/genética , Coelhos , Transcrição GênicaRESUMO
Herpes simplex virus 1 (HSV-1) establishes a lifelong latent infection in host peripheral neurons, including the neurons of the trigeminal ganglia (TG). HSV-1 can reactivate from neurons to cause recurrent infection. During latency, the insulator protein CTCF occupies DNA binding sites on the HSV-1 genome, and these sites have been previously characterized as functional enhancer-blocking insulators. Previously, CTCF was found to be dissociated from wild-type virus postreactivation but not in mutants that do not reactivate, indicating that CTCF eviction may also be an important component of reactivation. To further elucidate the role of CTCF in reactivation of HSV-1, we used recombinant adeno-associated virus (rAAV) vectors to deliver a small interfering RNA targeting CTCF to peripheral neurons latent with HSV-1 in rabbit TG. Our data show that CTCF depletion resulted in long-term and persistent shedding of infectious virus in the cornea and increased ICP0 expression in the ganglia, indicating that CTCF depletion facilitates HSV-1 reactivation.IMPORTANCE Increasing evidence has shown that the insulator protein CTCF regulates gene expression of DNA viruses, including the gammaherpesviruses. While CTCF occupation and insulator function control gene expression in DNA viruses, CTCF eviction has been correlated to increased lytic gene expression and the dissolution of transcriptional domains. Our previous data have shown that in the alphaherpesvirus HSV-1, CTCF was found to be dissociated from the HSV-1 genome postreactivation, further indicating a global role for CTCF eviction in the transition from latency to reactivation in HSV-1 genomes. Using an rAAV8, we targeted HSV-1-infected peripheral neurons for CTCF depletion to show that CTCF depletion precedes the shedding of infectious virus and increased lytic gene expression in vivo, providing the first evidence that CTCF depletion facilitates HSV-1 reactivation.
Assuntos
Fator de Ligação a CCCTC/genética , Técnicas de Inativação de Genes/métodos , Herpes Simples/genética , Herpesvirus Humano 1/fisiologia , Células 3T3 , Animais , Sítios de Ligação , Fator de Ligação a CCCTC/metabolismo , Córnea/virologia , Modelos Animais de Doenças , Gânglios/virologia , Genoma Viral , Herpes Simples/virologia , Herpesvirus Humano 1/química , Camundongos , Coelhos , Ativação Viral , Latência Viral , Eliminação de Partículas ViraisRESUMO
UNLABELLED: Following infection of epithelial tissues, herpes simplex virus 1 (HSV-1) virions travel via axonal transport to sensory ganglia and establish a lifelong latent infection within neurons. Recent studies have revealed that, following intraganglionic or intrathecal injection, recombinant adeno-associated virus (rAAV) vectors can also infect sensory neurons and are capable of stable, long-term transgene expression. We sought to determine if application of rAAV to peripheral nerve termini at the epithelial surface would allow rAAV to traffic to sensory ganglia in a manner similar to that seen with HSV. We hypothesized that footpad or ocular inoculation with rAAV8 would result in transduction of dorsal root ganglia (DRG) or trigeminal ganglia (TG), respectively. To test this, we inoculated the footpads of mice with various amounts of rAAV as well as rAAV capsid mutants. We demonstrated that this method of inoculation can achieve a transduction rate of >90% of the sensory neurons in the DRG that innervate the footpad. Similarly, we showed that corneal inoculation with rAAV vectors in the rabbit efficiently transduced >70% of the TG neurons in the optic tract. Finally, we demonstrated that coinfection of mouse footpads or rabbit eyes with rAAV vectors and HSV-1 resulted in colocalization in nearly all of the HSV-1-positive neurons. These results suggest that rAAV is a useful tool for the study of HSV-1 infection and may provide a means to deliver therapeutic cargos for the treatment of HSV infections or of dysfunctions of sensory ganglia. IMPORTANCE: Adeno-associated virus (AAV) has been shown to transduce dorsal root ganglion sensory neurons following direct intraganglionic sciatic nerve injection and intraperitoneal and intravenous injection as well as intrathecal injection. We sought to determine if rAAV vectors would be delivered to the same sensory neurons that herpes simplex virus (HSV-1) infects when applied peripherally at an epithelial surface that had been treated to expose the underlying sensory nerve termini. For this study, we chose two well-established HSV-1 infection models: mouse footpad infection and rabbit ocular infection. The results presented here provide the first description of AAV vectors transducing neurons following delivery at the skin/epithelium/eye. The ability of AAV to cotransduce HSV-1-infected neurons in both the mouse and the rabbit provides an opportunity to experimentally explore and disrupt host and viral proteins that are integral to the establishment of HSV-1 latency, to the maintenance of latency, and to reactivation from latency in vivo.
Assuntos
Dependovirus/crescimento & desenvolvimento , Dependovirus/genética , Vetores Genéticos , Herpesvirus Humano 1/crescimento & desenvolvimento , Células Receptoras Sensoriais/virologia , Transdução Genética , Animais , Coinfecção/virologia , Olho/virologia , Pé/virologia , Gânglios Espinais/virologia , Herpes Simples/virologia , Camundongos , Infecções por Parvoviridae/virologia , Coelhos , Gânglio Trigeminal/virologiaRESUMO
Six structural motifs based on the initial (lead) structure of merbarone were designed, prepared, and tested against the glioblastoma LN-229 cell line. Three different structural moieties were modified in the search for optimal glioblastoma activity: the 1,3-diazinane moiety, the aryl moiety, and the heteroatom linker. Calculated molecular descriptors such as lipophilicity (ClogP), acidic strength (calculated pKa), and polar surface area (PSA) were used to design a diverse structural library of these compounds. From six different structural motifs and 136 compounds, a handful of examples with moderate (100µg/ml), good (10µg/ml) and excellent (1µg/ml) glioblastoma activity were elucidated.
Assuntos
Antineoplásicos/farmacologia , Barbitúricos/farmacologia , Compostos de Fenilureia/farmacologia , Inibidores da Topoisomerase II/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Barbitúricos/síntese química , Barbitúricos/química , Carbamatos/química , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Glioblastoma , Humanos , Compostos de Fenilureia/síntese química , Compostos de Fenilureia/química , Tiobarbitúricos/química , Inibidores da Topoisomerase II/síntese química , Inibidores da Topoisomerase II/químicaRESUMO
Schiff base derivatives have recently been shown to possess antimicrobial activity, and these derivatives include a limited number of salicylaldehyde hydrazones. To further explore this structure-activity relationship between salicylaldehyde hydrazones and antifungal activity, we previously synthesized and analyzed a large series of salicylaldehyde and formylpyridinetrione hydrazones for their ability to inhibit fungal growth of both azole-susceptible and azole-resistant species of Candida. While many of these analogs showed excellent growth inhibition with low mammalian cell toxicity, their activity did not extend to azole-resistant species of Candida. To further dissect the structural features necessary to inhibit azole-resistant fungal species, we synthesized a new class of modified salicylaldehyde derivatives and subsequently identified a series of modified pyridine-based hydrazones that had potent fungicidal antifungal activity against multiple Candida spp. Here we would like to present our synthetic procedures as well as the results from fungal growth inhibition assays, mammalian cell toxicity assays, time-kill assays and synergy studies of these novel pyridine-based hydrazones on both azole-susceptible and azole-resistant fungal species.
Assuntos
Antifúngicos/síntese química , Candida albicans/efeitos dos fármacos , Candida glabrata/efeitos dos fármacos , Hidrazinas/síntese química , Piridinas/síntese química , Animais , Antifúngicos/farmacologia , Azóis/farmacologia , Candida albicans/crescimento & desenvolvimento , Candida glabrata/crescimento & desenvolvimento , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Farmacorresistência Fúngica , Células Hep G2 , Humanos , Hidrazinas/farmacologia , Testes de Sensibilidade Microbiana , Piridinas/farmacologia , Relação Estrutura-Atividade , Células VeroRESUMO
Efficient synthetic procedures for the preparation of acid hydrazines and hydrazides were developed by converting the corresponding carboxylic acid into the methyl ester catalyzed by Amberlyst-15, followed by a reaction with hydrazine monohydrate. Sulfohydrazides were prepared from the corresponding sulfonyl chlorides and hydrazine monohydrate. Both of these group of compounds were condensed with substituted salicylaldehydes using gradient concentration methods that generated a large library of hydrazone, hydrazide and sulfohydrazide analogs. Antifungal activity of the prepared analogs showed that salicylaldehyde hydrazones and hydrazides are potent inhibitors of fungal growth with little to no mammalian cell toxicity, making these analogs promising new targets for future therapeutic development.
Assuntos
Aldeídos/farmacologia , Antifúngicos/síntese química , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Hidrazinas/farmacologia , Hidrazonas/farmacologia , Aldeídos/síntese química , Aldeídos/química , Animais , Antifúngicos/química , Linhagem Celular , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Células Hep G2 , Humanos , Hidrazinas/síntese química , Hidrazinas/química , Hidrazonas/síntese química , Hidrazonas/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade , Células VeroRESUMO
Opportunistic fungal infections caused by the Candida spp. are the most common human fungal infections, often resulting in severe systemic infections-a significant cause of morbidity and mortality in at-risk populations. Azole antifungals remain the mainstay of antifungal treatment for candidiasis, however development of clinical resistance to azoles by Candida spp. limits the drugs' efficacy and highlights the need for discovery of novel therapeutics. Recently, it has been reported that simple hydrazone derivatives have the capability to potentiate antifungal activities in vitro. Similarly, pyrimidinetrione analogs have long been explored by medicinal chemists as potential therapeutics, with more recent focus being on the potential for pyrimidinetrione antimicrobial activity. In this work, we present the synthesis of a class of novel hydrazone-pyrimidinetrione analogs using novel synthetic procedures. In addition, structure-activity relationship studies focusing on fungal growth inhibition were also performed against two clinically significant fungal pathogens. A number of derivatives, including phenylhydrazones of 5-acylpyrimidinetrione exhibited potent growth inhibition at or below 10µM with minimal mammalian cell toxicity. In addition, in vitro studies aimed at defining the mechanism of action of the most active analogs provide preliminary evidence that these compound decrease energy production and fungal cell respiration, making this class of analogs promising novel therapies, as they target pathways not targeted by currently available antifungals.
Assuntos
Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Hidrazonas/farmacologia , Pirimidinonas/farmacologia , Animais , Antifúngicos/síntese química , Antifúngicos/química , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Hidrazonas/síntese química , Hidrazonas/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pirimidinonas/síntese química , Pirimidinonas/química , Relação Estrutura-Atividade , Células Vero/citologia , Células Vero/efeitos dos fármacosRESUMO
In herpes simplex virus 1 (HSV-1), binding clusters enriched in CTCF during latency have been previously identified. We hypothesized that CTCF binding to CTCF clusters in HSV-1 would be disrupted in a reactivation event. To investigate, CTCF occupation of three CTCF binding clusters in HSV-1 was analyzed following sodium butyrate (NaB)- and explant-induced reactivation in the mouse. Our data show that the CTCF domains positioned within the HSV-1 genome, specifically around the latency-associated transcript (LAT) and ICP0 and ICP4 regions of the genome, lose CTCF occupancy following the application of reactivation stimuli in wild-type virus. We also found that CTCF binding clusters upstream of the ICP0 and ICP4 promoters both function as classical insulators capable of acting as enhancer blockers of the LAT enhancer. Finally, our results suggest that CTCF occupation of domains in HSV-1 may be differentially regulated both during latency and at early times following reactivation by the presence of lytic transcripts and further implicate epigenetic regulation of HSV-1 as a critical component of the latency-reactivation transition.
Assuntos
Epigênese Genética/genética , Genoma Viral/genética , Herpesvirus Humano 1/genética , Proteínas Repressoras/metabolismo , Ativação Viral/genética , Latência Viral/genética , Análise de Variância , Animais , Fator de Ligação a CCCTC , Imunoprecipitação da Cromatina , Primers do DNA/genética , Epigênese Genética/fisiologia , Feminino , Herpesvirus Humano 1/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Reação em Cadeia da Polimerase em Tempo Real , Proteínas Repressoras/genética , Ativação Viral/fisiologiaRESUMO
The exact mechanisms of HSV-1 establishment, maintenance, latency, reactivation, and also the courses of recurrent ocular infections remain a mystery. Comprehensive understanding of the HSV-1 disease process could lead to prevention of HSV-1 acute infection, reactivation, and more effective treatments of recurrent ocular disease. Animal models have been used for over sixty years to investigate our concepts and hypotheses of HSV-1 diseases. In this paper we present descriptions and examples of rabbit and mouse eye models of HSV-1 latency, reactivation, and recurrent diseases. We summarize studies in animal models of spontaneous and induced HSV-1 reactivation and recurrent disease. Numerous stimuli that induce reactivation in mice and rabbits are described, as well as factors that inhibit viral reactivation from latency. The key features, advantages, and disadvantages of the mouse and rabbit models in relation to the study of ocular HSV-1 are discussed. This paper is pertinent but not intended to be all inclusive. We will give examples of key papers that have reported novel discoveries related to the review topics.
Assuntos
Infecções Oculares Virais/fisiopatologia , Infecções Oculares Virais/virologia , Herpes Simples/fisiopatologia , Herpes Simples/virologia , Herpesvirus Humano 1/fisiologia , Ativação Viral/fisiologia , Latência Viral/fisiologia , Animais , Modelos Animais de Doenças , Humanos , Coelhos , Recidiva , Especificidade da EspécieRESUMO
HSV-1 is a human pathogen that establishes a lifelong infection in the host. HSV-1 is transported by retrograde axonal transport to sensory neurons in the peripheral nervous system where latent viral genomes can reactivate. The resulting virus travels via anterograde axonal transport to the periphery and can cause clinical disease. CTCF insulators flank the LAT and IE regions of HSV-1 and during latency and maintain the integrity of transcriptional domains through a myriad of functions, including enhancer-blocking or barrier-insulator functions. Importantly, during reactivation, CTCF protein is evicted from the HSV-1 genome, especially from the CTRL2 insulator. CTRL2 is a functional insulator downstream of the 5'exon region of the LAT, so these results suggest that the disruption of this insulator may be required for efficient HSV-1 reactivation. To further explore this, we used a recombinant virus containing a deletion of the CTRL2 insulator (ΔCTRL2) in a rabbit ocular model of HSV-1 infection and induced reactivation. We show that, in the absence of the CTRL2 insulator, HSV-1 established an equivalent latent infection in rabbits, but those rabbits failed to efficiently reactivate from latency. Furthermore, we found a significant decrease in the expression of the gene Us9-, a gene that codes for a type II membrane protein that has been shown to be required for anterograde transport in neurons. Taken together, these results suggest that the functions of the CTRL2 insulator and Us9 activation in reactivating neurons are intrinsically linked through the regulation of a gene responsible for the axonal transport of HSV-1 to the periphery.
Assuntos
Herpes Simples , Herpesvirus Humano 1 , Animais , Transporte Axonal/genética , Fator de Ligação a CCCTC/genética , Fator de Ligação a CCCTC/metabolismo , Genoma Viral , Herpes Simples/genética , Herpesvirus Humano 1/fisiologia , CoelhosRESUMO
Invasive fungal infections pose a significant problem to the immune-compromised. Moreover, increased resistance to common antifungals requires development of novel compounds that can be used to treat invasive fungal infections. Naturally occurring steroidal glycosides have been shown to possess a range of functional antimicrobial properties, but synthetic methodology for their development hinders thorough exploration of this class of molecules and the structural components required for broad spectrum antifungal activity. In this report, we outline a novel approach to the synthesis of glycoside-linked functionalized 2α,3ß-cholestane and spirostane molecules and present data from in vitro screenings of the antifungal activities against human fungal pathogens and as well as mammalian cell toxicity of these derivatives.
Assuntos
Antifúngicos/química , Oligossacarídeos/química , Esteroides/química , Antifúngicos/síntese química , Antifúngicos/farmacologia , Colestanos/química , Fungos/efeitos dos fármacos , Glicosídeos/síntese química , Glicosídeos/química , Glicosídeos/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Espirostanos/química , EstereoisomerismoRESUMO
Invasive fungal infections are a major complication for individuals with compromised immune systems. One of the most significant challenges in the treatment of invasive fungal infections is the increased resistance of many organisms to widely used antifungals, making the development of novel antifungal agents essential. Many naturally occurring products have been found to be effective antimicrobial agents. In particular, saponins with spirostane glycosidic moieties-isolated from plant or marine species-have been shown to possess a range of antimicrobial properties. In this report, we outline a novel approach to the synthesis of a number of functionalized spirostane molecules that can be further used as building blocks for novel spirostane-linked glycosides and present results from the in vitro screenings of the antifungal potential of each derivative against four fungal species, including Candida albicans, Cryptococcus neoformans, Candida glabrata, and the filamentous fungus Aspergillus fumigatus.
Assuntos
Antifúngicos/síntese química , Antifúngicos/farmacologia , Fungos/efeitos dos fármacos , Espirostanos/síntese química , Espirostanos/farmacologia , Antifúngicos/química , Aspergillus fumigatus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Candida glabrata/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Isomerismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Espirostanos/químicaRESUMO
Synthetic modifications of cholesterol and other traditional steroid molecules have become a promising area for the exploration and development of novel antifungal agents, especially with respect to the development of fatty-acid esters of steroids. In addition, 2,3-functionalized steroids are also compounds with potentially interesting biological properties and proper functionalization of 2,3-steroids can lead to the development of efficient syntheses of building blocks for novel fatty-acid esters of steroids. In this Letter, we outline a novel and efficient approach to the synthesis of 2,3-functionalized cholestane and androstane derivatives and present their promising preliminary antifungal activities against a number of fungal species.
Assuntos
Androstanos/química , Antifúngicos/síntese química , Colestanos/química , Androstanos/síntese química , Androstanos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Colestanos/síntese química , Colestanos/farmacologia , Colesterol/química , Testes de Sensibilidade Microbiana , Relação Estrutura-AtividadeRESUMO
Glioblastoma multiforme (GBM) is the most aggressive form of primary human gliomas. While chemotherapy using the DNA alkylating agent temozolomide (TMZ) is a first line treatment for GBMs, the development of resistance to TMZ is a common limitation to successful treatment. Human Cytomegalovirus (HCMV) is a ubiquitous ß-herpesvirus that establishes a lifelong infection latent infection in host haematopoetic cells, where lytic replication of the virus is silenced. HCMV can also establish a persistent infection in hosts, where low levels of virus are lytically produced. Furthermore, multiple studies have identified HCMV DNA and/or proteins in human GBM samples, and have shown that acute infection with HCMV confers a glioblastoma stem cell (GSC) phenotype, further supporting an oncomodulatory role for HCMV in GBM progression and severity. In this current study, we examined the long-term effects of HCMV persistence to cell viability, cell proliferation, and the development of TMZ resistance over time using a glioblastoma cell line known as LN-229. Persistent HCMV infections were established and maintained in this cell line for 30 weeks without the addition of new virus. Here, we report that HCMV persistence in this cell line resulted in increased cell viability, increased cell proliferation, and a marked resistance to the DNA alkylating agent, TMZ, over time, suggesting that low levels of lytically replicating HCMV could contribute to tumor progression in GBM.