ABSTRACT
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic double-stranded DNA virus and the etiologic agent of Kaposi's sarcoma and hyperinflammatory lymphoproliferative disorders. Understanding the mechanism by which KSHV increases the infected cell population is crucial for curing KSHV-associated diseases. Using scRNA-seq, we demonstrate that KSHV preferentially infects CD14+ monocytes, sustains viral lytic replication through the viral interleukin-6 (vIL-6), which activates STAT1 and 3, and induces an inflammatory gene expression program. To study the role of vIL-6 in monocytes upon KSHV infection, we generated recombinant KSHV with premature stop codon (vIL-6(-)) and its revertant viruses (vIL-6(+)). Infection of the recombinant viruses shows that both vIL-6(+) and vIL-6(-) KSHV infection induced indistinguishable host anti-viral response with STAT1 and 3 activations in monocytes; however, vIL-6(+), but not vIL-6(-), KSHV infection promoted the proliferation and differentiation of KSHV-infected monocytes into macrophages. The macrophages derived from vIL-6(+) KSHV infection showed a distinct transcriptional profile of elevated IFN-pathway activation with immune suppression and were compromised in T-cell stimulation function compared to those from vIL-6(-) KSHV infection or uninfected control. Notably, a viral nuclear long noncoding RNA (PAN RNA), which is required for sustaining KSHV gene expression, was substantially reduced in infected primary monocytes upon vIL-6(-) KSHV infection. These results highlight the critical role of vIL-6 in sustaining KSHV transcription in primary monocytes. Our findings also imply a clever strategy in which KSHV utilizes vIL-6 to secure its viral pool by expanding infected monocytes via differentiating into longer-lived dysfunctional macrophages. This mechanism may facilitate KSHV to escape from host immune surveillance and to support a lifelong infection.
Subject(s)
Herpesviridae Infections , Herpesvirus 8, Human , Sarcoma, Kaposi , Humans , Herpesvirus 8, Human/physiology , Interleukin-6/metabolism , Monocytes/metabolism , Herpesviridae Infections/metabolism , Macrophages/metabolism , Immunologic Factors/metabolism , Virus ReplicationABSTRACT
Kaposi sarcoma-associated herpesvirus (KSHV) inflammatory cytokine syndrome (KICS) is a newly described chronic inflammatory disease condition caused by KSHV infection and is characterized by high KSHV viral load and sustained elevations of serum KSHV-encoded IL-6 (vIL-6) and human IL-6 (hIL-6). KICS has significant immortality and greater risks of other complications, including malignancies. Although prolonged inflammatory vIL-6 exposure by persistent KSHV infection is expected to have key roles in subsequent disease development, the biological effects of prolonged vIL-6 exposure remain elusive. Using thiol(SH)-linked alkylation for the metabolic (SLAM) sequencing and Cleavage Under Target & Release Using Nuclease analysis (CUT&RUN), we studied the effect of prolonged vIL-6 exposure in chromatin landscape and resulting cytokine production. The studies showed that prolonged vIL-6 exposure increased Bromodomain containing 4 (BRD4) and histone H3 lysine 27 acetylation co-occupancies on chromatin, and the recruitment sites were frequently co-localized with poised RNA polymerase II with associated enzymes. Increased BRD4 recruitment on promoters was associated with increased and prolonged NF-κB p65 binding after the lipopolysaccharide stimulation. The p65 binding resulted in quicker and sustained transcription bursts from the promoters; this mechanism increased total amounts of hIL-6 and IL-10 in tissue culture. Pretreatment with the BRD4 inhibitors, OTX015 and MZ1, eliminated the enhanced inflammatory cytokine production. These findings suggest that persistent vIL-6 exposure may establish a chromatin landscape favorable for the reactivation of inflammatory responses in monocytes. This epigenetic memory may explain the greater risk of chronic inflammatory disease development in KSHV-infected individuals.
Subject(s)
Herpesviridae Infections , Herpesvirus 8, Human , Sarcoma, Kaposi , Humans , Herpesvirus 8, Human/physiology , Interleukin-6/metabolism , Nuclear Proteins/metabolism , Transcription Factors/metabolism , Cytokines/metabolism , Herpesviridae Infections/metabolism , Chromatin/metabolism , Epigenesis, Genetic , Cell Cycle Proteins/metabolismABSTRACT
Eukaryotic genomes are structurally organized via the formation of multiple loops that create gene expression regulatory units called topologically associating domains (TADs). Here we revealed the KSHV TAD structure at 500 bp resolution and constructed a 3D KSHV genomic structural model with 2 kb binning. The latent KSHV genome formed very similar genomic architectures in three different naturally infected PEL cell lines and in an experimentally infected epithelial cell line. The majority of the TAD boundaries were occupied by structural maintenance of chromosomes (SMC1) cohesin complex and CCCTC-binding factor (CTCF), and the KSHV transactivator was recruited to those sites during reactivation. Triggering KSHV gene expression decreased prewired genomic loops within the regulatory unit, while contacts extending outside of regulatory borders increased, leading to formation of a larger regulatory unit with a shift from repressive to active compartments (B to A). The 3D genomic structural model proposes that the immediate early promoter region is localized on the periphery of the 3D viral genome during latency, while highly inducible noncoding RNA regions moved toward the inner space of the structure, resembling the configuration of a "bird cage" during reactivation. The compartment-like properties of viral episomal chromatin structure and its reorganization during the transition from latency may help facilitate viral gene transcription. IMPORTANCE The 3D architecture of chromatin allows for efficient arrangement, expression, and replication of genetic material. The genomes of all organisms studied to date have been found to be organized through some form of tiered domain structures. However, the architectural framework of the genomes of large double-stranded DNA viruses such as the herpesvirus family has not been reported. Prior studies with Kaposi's sarcoma-associated herpesvirus (KSHV) have indicated that the viral chromatin shares many biological properties exhibited by the host cell genome, essentially behaving as a mini human chromosome. Thus, we hypothesized that the KSHV genome may be organized in a similar manner. In this report, we describe the domain structure of the latent and lytic KSHV genome at 500 bp resolution and present a 3D genomic structural model for KSHV under each condition. These results add new insights into the complex regulation of the viral life cycle.
Subject(s)
Chromatin , Herpesvirus 8, Human , Chromatin/genetics , Gene Expression Regulation, Viral , Genome, Viral , Herpesvirus 8, Human/genetics , Humans , Trans-Activators/genetics , Virus Latency/geneticsABSTRACT
OBJECTIVE: Cancer patient-derived organoids (PDOs) grow as three dimensional (3D) structures in the presence of extracellular matrix and have been found to represent the original tumor's genetic complexity. In addition, PDOs can be grown and subjected to drug sensitivity testing in a shorter time course and with lesser expense than patient-derived xenograft models. Many patients with recurrent ovarian cancer develop malignant effusions that become refractory to chemotherapy. Since these same patients often present for palliative aspiration of ascites or pleural effusions, there is a potential opportunity to obtain tumor specimens in the form of multicellular spheroids (MCS) present in malignant effusion fluids. Our objective was to develop a short duration culture of MCS from ovarian cancer malignant effusions in conditions selected to support organoid growth and use them as a platform for empirical drug sensitivity testing. METHODS: In this study, malignant effusion specimens were collected from patients with high-grade serous ovarian carcinoma (HGSOC). MCS were recovered and subjected to culture conditions designed to support organoid growth. In a subset of specimens, RNA-sequencing was performed at two time points during the short-term culture to determine changes in transcriptome in response to culture conditions. Organoid induction was also characterized in these specimens using Ki67 staining and histologic analysis. Drug sensitivity testing was performed on all specimens. RESULTS: Our model describes organoids formed within days of primary culture, which can recapitulate the histological features of malignant ascites fluid and can be expanded for at least 6 days. RNA-seq analysis of four patient specimens showed that within 6 days of culture, there was significant up-regulation of genes related to cellular proliferation, epithelial-mesenchymal transition, and KRAS signaling pathways. Drug sensitivity testing identified several agents with therapeutic potential. CONCLUSIONS: Short duration organoid culture of MCS from HGSOC malignant effusions can be used as a platform for empiric drug sensitivity testing. These ex vivo models may be helpful in screening new or existing therapeutic agents prior to individualized treatment options.
Subject(s)
Cystadenoma, Serous/pathology , Organ Culture Techniques/methods , Organoids/physiopathology , Aged , Cystadenoma, Serous/drug therapy , Female , Humans , Middle Aged , Neoplasm Grading , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/pathologyABSTRACT
In order to develop a practical model of breast cancer, with in vitro and syngeneic, immune-intact, in vivo growth capacity, we established a primary cell line derived from a mammary carcinoma in the transgenic FVB/N-Tg(MMTV-ErbB2*)NDL2-5Mul mouse, referred to as "NDLUCD". The cell line is adapted to standard cell culture and can be transplanted into syngeneic FVB/N mice. The line maintains a stable phenotype over multiple in vitro passages and rounds of in vivo transplantation. NDLUCD tumors in FVB/N mice exhibit high expression of ErbB2 and ErbB3 and signaling molecules downstream of ErbB2. The syngeneic transplant tumors elicit an immune reaction in the adjacent stroma, detected and characterized using histology, immunophenotyping, and gene expression. NDLUCD cells also express PD-L1 in vivo and in vitro, and in vivo transplants are reactive to anti-immune checkpoint therapy with responses conducive to immunotherapy studies. This new NDLUCD cell line model is a practical alternative to the more commonly used 4T1 cells, and our previously described FVB/N-Tg(MMTV-PyVT)634Mul derived Met-1fvb2 and FVB/NTg(MMTV-PyVTY315F/Y322F) derived DB-7fvb2 cell lines. The NDLUCD cells have, so far, remained genetically and phenotypically stable over many generations, with consistent and reproducible results in immune intact preclinical cohorts.
Subject(s)
Antineoplastic Agents, Immunological/pharmacology , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Breast Neoplasms/drug therapy , Carcinoma/drug therapy , Mammary Neoplasms, Experimental/drug therapy , Receptor, ErbB-2/genetics , Animals , Antineoplastic Agents, Immunological/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , B7-H1 Antigen/antagonists & inhibitors , B7-H1 Antigen/immunology , Breast Neoplasms/genetics , Breast Neoplasms/immunology , Breast Neoplasms/pathology , Carcinoma/genetics , Carcinoma/immunology , Carcinoma/pathology , Cell Line, Tumor/transplantation , Drug Screening Assays, Antitumor/methods , Feasibility Studies , Female , Humans , Mammary Neoplasms, Experimental/genetics , Mammary Neoplasms, Experimental/immunology , Mammary Neoplasms, Experimental/pathology , Mice , Mice, Transgenic , Primary Cell Culture , Receptor, ErbB-2/antagonists & inhibitors , Reproducibility of ResultsABSTRACT
Several studies by our group and others have determined that expression levels of Bcl-2 and/or Bcl-xL, pro-survival molecules which are associated with chemoresistance, are elevated in patients with muscle invasive bladder cancer (MI-BC). The goal of this study was to determine whether combining Obatoclax, a BH3 mimetic which inhibits pro-survival Bcl-2 family members, can improve responses to cisplatin chemotherapy, the standard of care treatment for MI-BC. Three MI-BC cell lines (T24, TCCSuP, 5637) were treated with Obatoclax alone or in combination with cisplatin and/or pre-miR-34a, a molecule which we have previously shown to inhibit MI-BC cell proliferation via decreasing Cdk6 expression. Proliferation, clonogenic, and apoptosis assays confirmed that Obatoclax can decrease cell proliferation and promote apoptosis in a dose-dependent manner. Combination treatment experiments identified Obatoclax + cisplatin as the most effective treatment. Immunoprecipitation and Western analyses indicate that, in addition to being able to inhibit Bcl-2 and Bcl-xL, Obatoclax can also decrease cyclin D1 and Cdk4/6 expression levels. This has not previously been reported. The combined data demonstrate that Obatoclax can inhibit cell proliferation, promote apoptosis, and significantly enhance the effectiveness of cisplatin in MI-BC cells via mechanisms that likely involve the inhibition of both pro-survival molecules and cell cycle regulators.
Subject(s)
Cisplatin/pharmacology , Pyrroles/pharmacology , Urinary Bladder Neoplasms/metabolism , Urinary Bladder/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Cyclin D1/metabolism , Cyclin-Dependent Kinase 4/metabolism , Cyclin-Dependent Kinase 6/metabolism , Dose-Response Relationship, Drug , Drug Synergism , Gene Expression Regulation, Neoplastic/drug effects , Humans , Indoles , Neoplasm Invasiveness , Proto-Oncogene Proteins c-bcl-2/metabolism , Urinary Bladder/drug effects , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/pathology , bcl-X Protein/metabolismABSTRACT
BACKGROUND: An exploratory study was performed to determine the prevalence of the patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs78409 [G] allele among the Hmong as a risk factor for nonalcoholic fatty liver disease (NAFLD). NAFLD/nonalcoholic steatohepatitis is the world's most common chronic liver disease and is expected to replace viral hepatitis as the leading cause of cirrhosis and potential precursor to hepatocellular carcinoma (HCC). Of all populations in California, the Hmong experience the highest risk of death from HCC and the highest prevalence of metabolic syndrome risk factors among Asians that predispose them to NAFLD. Here a genetic explanation was sought for the high rates of chronic liver disease among the Hmong. The literature pointed to the PNPLA3 rs738409 [G] allele as a potential genetic culprit. METHODS: Cell-free DNA was isolated from 26 serum samples previously collected in community settings. Quantitative polymerase chain reaction-based single-nucleotide polymorphism (SNP) genotyping was performed with a validated TaqMan SNP genotyping assay, and results were analyzed with TaqMan Genotyper software. RESULTS: The PNPLA3 rs738409 [C>G] variant occurred at a frequency of 0.46 (12 of 26; 95% confidence interval, 0.27-0.67). This carrier rate would rank the Hmong as the third highest population in the 1000 Genomes Project. CONCLUSIONS: Although this small sample size limits the generalizability, the high frequency rates of this allele along with the presence of metabolic syndrome risk factors warrant further studies into the etiology of NAFLD among the Hmong. Cancer 2018;124:1583-9. © 2018 American Cancer Society.
Subject(s)
Asian/genetics , Genetic Predisposition to Disease , Lipase/genetics , Liver Cirrhosis/genetics , Membrane Proteins/genetics , Polymorphism, Single Nucleotide , Adult , Aged , California/epidemiology , Chronic Disease , Female , Follow-Up Studies , Genotype , Humans , Incidence , Liver Cirrhosis/epidemiology , Male , Middle Aged , Prognosis , Young AdultABSTRACT
Bivalent histone modifications are defined as repressive and activating epigenetic marks that simultaneously decorate the same genomic region. The H3K27me3 mark silences gene expression, while the H3K4me3 mark prevents the region from becoming permanently silenced and prepares the domain for activation when needed. Specific regions of Kaposi's sarcoma-associated herpesvirus (KSHV) latent episomes are poised to be activated by the KSHV replication and transcription activator (K-Rta). How KSHV episomes are prepared such that they maintain latent infection and switch to lytic replication by K-Rta remains unclear. K-Rta transactivation activity requires a protein degradation function; thus, we hypothesized that identification of cellular substrates of K-Rta may provide insight into the maintenance of KSHV latent infection and the switch to lytic replication. Here we show that a zinc finger protein, ZIC2, a key regulator for central nervous system development, is a substrate of K-Rta and is responsible for maintaining latency. K-Rta directly interacted with ZIC2 and functioned as an E3 ligase to ubiquitinate ZIC2. ZIC2 localized at immediate early and early gene cluster regions of the KSHV genome and contributed to tethering of polycomb repressive complex 2 through physical interaction, thus maintaining H3K27me3 marks at the K-Rta promoter. Accordingly, depletion of ZIC2 shifted the balance of bivalent histone modifications toward more active forms and induced KSHV reactivation in naturally infected cells. We suggest that ZIC2 turnover by K-Rta is a strategy employed by KSHV to favor the transition from latency to lytic replication.IMPORTANCE Posttranslational histone modifications regulate the accessibility of transcriptional factors to DNA; thus, they have profound effects on gene expression (e.g., viral reactivation). KSHV episomes are known to possess bivalent chromatin domains. How such KSHV chromatin domains are maintained to be reactivatable by K-Rta remains unclear. We found that ZIC2, a transcriptional factor essential for stem cell pluripotency, plays a role in maintaining KSHV latent infection in naturally infected cells. We found that ZIC2 degradation by K-Rta shifts bivalent histone marks to a more active configuration, leading to KSHV reactivation. ZIC2 interacts with and maintains polycomb repressor complex 2 at the K-Rta promoter. Our findings uncover (i) a mechanism utilized by KSHV to maintain latent infection, (ii) a latency-lytic cycle switch operated by K-Rta, and (iii) a molecular mechanism of ZIC2-mediated local histone modification.
ABSTRACT
The COVID-19 pandemic exacerbated racism experienced by Asian Americans, especially women and older individuals. Little is known about how discriminatory experiences during the pandemic have influenced health behaviors among Asian Americans. Between 10/2021 and 6/2022, we surveyed 193 Asian American women in the San Francisco area. Participants were asked to report types of discrimination they experienced since March 2020. We explored bivariable associations of discrimination and changes in health behaviors and healthcare utilization. Most women were Chinese American (75%) and over 45-years-old (87%). The top three discriminatory experiences reported were being treated with less respect (60%), being treated unfairly at restaurants/stores (49%), and people acting as if they are better (47%). Chinese American women (vs. non-Chinese Asian American women) reported higher frequencies of being threatened/harassed (40% vs. 22%). Women who reported any discriminatory experience (vs. none) were more likely to report less physical exercise (42.7% vs. 26.3%) and canceling/rescheduling medical appointments (65.0% vs. 45.1%). Our findings begin to elucidate Asian American women's experiences of discrimination since the pandemic and provide evidence of the harmful impacts of anti-Asian racism on health behaviors.
Subject(s)
COVID-19 , Racism , Humans , Female , Middle Aged , Asian , Pandemics , Health Behavior , ExerciseABSTRACT
N-Myc is a key driver of neuroblastoma and neuroendocrine prostate cancer (NEPC). One potential way to circumvent the challenge of undruggable N-Myc is to target the protein homeostasis (proteostasis) system that maintains N-Myc levels. Here, we identify heat shock protein 70 (HSP70) as a top partner of N-Myc, which binds a conserved "SELILKR" motif and prevents the access of E3 ubiquitin ligase, STIP1 homology and U-box containing protein 1 (STUB1), possibly through steric hindrance. When HSP70's dwell time on N-Myc is increased by treatment with the HSP70 allosteric inhibitor, STUB1 is in close proximity with N-Myc and becomes functional to promote N-Myc ubiquitination on the K416 and K419 sites and forms polyubiquitination chains linked by the K11 and K63 sites. Notably, HSP70 inhibition significantly suppressed NEPC tumor growth, increased the efficacy of aurora kinase A (AURKA) inhibitors, and limited the expression of neuroendocrine-related pathways.
Subject(s)
HSP70 Heat-Shock Proteins , Prostatic Neoplasms , Proteostasis , Ubiquitin-Protein Ligases , Ubiquitination , Male , Humans , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Prostatic Neoplasms/genetics , HSP70 Heat-Shock Proteins/metabolism , Ubiquitin-Protein Ligases/metabolism , Ubiquitin-Protein Ligases/genetics , Ubiquitination/drug effects , Cell Line, Tumor , Animals , Aurora Kinase A/metabolism , Aurora Kinase A/genetics , Aurora Kinase A/antagonists & inhibitors , N-Myc Proto-Oncogene Protein/metabolism , N-Myc Proto-Oncogene Protein/genetics , Mice , Carcinoma, Neuroendocrine/metabolism , Carcinoma, Neuroendocrine/genetics , Carcinoma, Neuroendocrine/drug therapy , Carcinoma, Neuroendocrine/pathology , Neuroendocrine Tumors/metabolism , Neuroendocrine Tumors/drug therapy , Neuroendocrine Tumors/genetics , Neuroendocrine Tumors/pathologyABSTRACT
Potential systemic factors contributing to aging-associated breast cancer (BC) remain elusive. Here, we reveal that the polyploid giant cells (PGCs) that contain more than two sets of genomes prevailing in aging and cancerous tissues constitute 5-10% of healthy female bone marrow mesenchymal stromal cells (fBMSCs). The PGCs can repair DNA damage and stimulate neighboring cells for clonal expansion. However, dying PGCs in advanced-senescent fBMSCs can form "spikings" which are then separated into membraned mtDNA-containing vesicles (Senescent PGC-Spiking Bodies; SPSBs). SPSB-phagocytosed macrophages accelerate aging with diminished clearance on BC cells and protumor M2 polarization. SPSB-carried mitochondrial OXPHOS components are enriched in BC of elder patients and associated with poor prognosis. SPSB-incorporated breast epithelial cells develop aggressive characteristics and PGCs resembling the polyploid giant cancer cells (PGCCs) in clonogenic BC cells and cancer tissues. These findings highlight an aging BMSC-induced BC risk mediated by SPSB-induced macrophage dysfunction and epithelial cell precancerous transition. SIGNIFICANCE: Mechanisms underlying aging-associated cancer risk remain unelucidated. This work demonstrates that polyploid giant cells (PGCs) in bone marrow mesenchymal stromal cells (BMSCs) from healthy female bone marrow donors can boost neighboring cell proliferation for clonal expansion. However, the dying-senescent PGCs in the advanced-senescent fBMSCs can form "spikings" which are separated into mitochondrial DNA (mtDNA)-containing spiking bodies (senescent PGC-spiking bodies; SPSBs). The SPSBs promote macrophage aging and breast epithelial cell protumorigenic transition and form polyploid giant cancer cells. These results demonstrate a new form of ghost message from dying-senescent BMSCs, that may serve as a systemic factor contributing to aging-associated immunosuppression and breast cancer risk.
ABSTRACT
The Kaposi sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a multifunctional protein with roles in gene regulation and maintenance of viral latency. Post-translational modification of LANA is important for functional diversification. Here, we report that LANA is subject to arginine methylation by protein arginine methyltransferase 1 in vitro and in vivo. The major arginine methylation site in LANA was mapped to arginine 20. This site was mutated to either phenylalanine (bulky hydrophobic, constitutive methylated mimetic) or lysine (positively charged, non-arginine methylatable) residues. The significance of the methylation in LANA function was examined in both the isolated form and in the context of the viral genome through the generation of recombinant KSHV. In addition, authentic LANA binding sites on the KSHV episome in naturally infected cells were identified using a whole genome KSHV tiling array. Although mutation of the methylation site resulted in no significant difference in KSHV LANA subcellular localization, we found that the methylation mimetic mutation resulted in augmented histone binding in vitro and increased LANA occupancy at identified LANA target promoters in vivo. Moreover, a cell line carrying the methylation mimetic mutant KSHV showed reduced viral gene expression relative to controls both in latency and in the course of reactivation. These results suggest that residue 20 is important for modulation of a subset of LANA functions and properties of this residue, including the hydrophobic character induced by arginine methylation, may contribute to the observed effects.
Subject(s)
Antigens, Viral/metabolism , Herpesvirus 8, Human/metabolism , Nuclear Proteins/metabolism , Protein-Arginine N-Methyltransferases/metabolism , Repressor Proteins/metabolism , Antigens, Viral/chemistry , Antigens, Viral/genetics , Arginine/metabolism , Base Sequence , Binding Sites , Chromatin/metabolism , Genetic Engineering , Genome, Viral/genetics , HEK293 Cells , Herpesvirus 8, Human/genetics , Herpesvirus 8, Human/physiology , Histones/chemistry , Histones/metabolism , Humans , Intracellular Space/metabolism , Methylation , Mutation , Nuclear Proteins/chemistry , Nuclear Proteins/genetics , Protein Multimerization , Protein Structure, Quaternary , Protein Transport , Transcription, Genetic , Virus LatencyABSTRACT
BACKGROUND: SUMOylation, as part of the epigenetic regulation of transcription, has been intensively studied in lower eukaryotes that contain only a single SUMO protein; however, the functions of SUMOylation during mammalian epigenetic transcriptional regulation are largely uncharacterized. Mammals express three major SUMO paralogues: SUMO-1, SUMO-2, and SUMO-3 (normally referred to as SUMO-1 and SUMO-2/3). Herpesviruses, including Kaposi's sarcoma associated herpesvirus (KSHV), seem to have evolved mechanisms that directly or indirectly modulate the SUMO machinery in order to evade host immune surveillance, thus advancing their survival. Interestingly, KSHV encodes a SUMO E3 ligase, K-bZIP, with specificity toward SUMO-2/3 and is an excellent model for investigating the global functional differences between SUMO paralogues. RESULTS: We investigated the effect of experimental herpesvirus reactivation in a KSHV infected B lymphoma cell line on genomic SUMO-1 and SUMO-2/3 binding profiles together with the potential role of chromatin SUMOylation in transcription regulation. This was carried out via high-throughput sequencing analysis. Interestingly, chromatin immunoprecipitation sequencing (ChIP-seq) experiments showed that KSHV reactivation is accompanied by a significant increase in SUMO-2/3 modification around promoter regions, but SUMO-1 enrichment was absent. Expression profiling revealed that the SUMO-2/3 targeted genes are primarily highly transcribed genes that show no expression changes during viral reactivation. Gene ontology analysis further showed that these genes are involved in cellular immune responses and cytokine signaling. High-throughput annotation of SUMO occupancy of transcription factor binding sites (TFBS) pinpointed the presence of three master regulators of immune responses, IRF-1, IRF-2, and IRF-7, as potential SUMO-2/3 targeted transcriptional factors after KSHV reactivation. CONCLUSION: Our study is the first to identify differential genome-wide SUMO modifications between SUMO paralogues during herpesvirus reactivation. Our findings indicate that SUMO-2/3 modification near protein-coding gene promoters occurs in order to maintain host immune-related gene unaltered during viral reactivation.
Subject(s)
Chromatin/metabolism , Herpesvirus 8, Human/physiology , Small Ubiquitin-Related Modifier Proteins/metabolism , Sumoylation , Ubiquitins/metabolism , Virus Activation , Cell Line, Tumor , Chromatin/virology , Chromatin Immunoprecipitation , Epigenesis, Genetic/immunology , Gene Ontology , Genes, MHC Class II , HEK293 Cells , Humans , Interferon Regulatory Factors/genetics , Interferon Regulatory Factors/metabolism , Promoter Regions, Genetic , Protein Binding , Transcription Factors/metabolism , TranscriptomeABSTRACT
Localized chromatin modifications of histone tails play an important role in regulating gene transcription, and aberration of these processes leads to carcinogenesis. Methylated histone lysine residues, a key player in chromatin remodeling, are demethylated by the JmjC class of enzymes. Here we show that JMJD5 (now renamed KDM8), a JmjC family member, demethylates H3K36me2 and is required for cell cycle progression. Chromatin immunoprecipitation assays applied to human genome tiling arrays in conjunction with RNA microarray revealed that KDM8 occupies the coding region of cyclin A1 and directly regulates transcription. Mechanistic analyses showed that KDM8 functioned as a transcriptional activator by inhibiting HDAC recruitment via demethylation of H3K36me2, an epigenetic repressive mark. Tumor array experiments revealed KDM8 is overexpressed in several types of cancer. In addition, loss-of-function studies in MCF7 cells leads to cell cycle arrest. These studies identified KDM8 as an important cell cycle regulator.
Subject(s)
Cell Proliferation , Cyclin A1/metabolism , Histone Demethylases/metabolism , Neoplasms/metabolism , Neoplasms/pathology , Open Reading Frames , Acetylation , Cell Line, Tumor , Cyclin A1/genetics , Gene Expression Regulation, Neoplastic , Histone Demethylases/genetics , Histones/metabolism , Humans , Neoplasms/genetics , RNA Interference , Transcription, GeneticABSTRACT
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic double-stranded DNA virus and the etiologic agent of Kaposi's sarcoma and hyperinflammatory lymphoproliferative disorders. Understanding the mechanism by which KSHV increases the infected cell population is crucial for curing KSHV-associated diseases. Here we demonstrate that KSHV preferentially infects CD14 + monocytes and sustains viral replication through the viral interleukin-6 (vIL6)-mediated activation of STAT1 and 3. Using vIL6-sufficient and vIL6-deficient recombinant KSHV, we demonstrated that vIL6 plays a critical role in promoting the proliferation and differentiation of KSHV-infected monocytes into macrophages. The macrophages derived from vIL6-sufficient KSHV infection showed a distinct transcriptional profile of elevated IFN-pathway activation with immune suppression and were compromised in T-cell stimulation function compared to those from vIL6-deficient KSHV infection or uninfected control. These results highlight a clever strategy, in which KSHV utilizes vIL6 to secure its viral pool by expanding infected dysfunctional macrophages. This mechanism also facilitates KSHV to escape from host immune surveillance and to establish a lifelong infection. 160. Summary: KSHV causes multiple inflammatory diseases, however, the underlying mechanism is not clear. Shimoda et al. demonstrate that KSHV preferentially infects monocytes and utilizes virally encoded interleukin-6 to expand and deregulate infected monocytes. This helps the virus escape from host immune surveillance.
ABSTRACT
The observed sex disparity in bladder cancer (BlCa) argues that androgen receptor (AR) signaling has a role in these malignancies. BlCas express full-length AR (FL-AR), constitutively active AR splice variants, including AR-v19, or both, and their depletion limits BlCa viability. However, the mechanistic basis of AR-dependence is unknown. Here, we depleted FL-AR, AR-v19, or all AR forms (T-AR), and performed RNA-seq studies to uncover that different AR forms govern distinct but partially overlapping transcriptional programs. Overlapping alterations include a decrease in mTOR and an increase of hypoxia regulated transcripts accompanied by a decline in oxygen consumption rate (OCR). Queries of BlCa databases revealed a significant negative correlation between AR expression and multiple hypoxia-associated transcripts arguing that this regulatory mechanism is a feature of high-grade malignancies. Our analysis of a 1600-compound library identified niclosamide as a strong ATPase inhibitor that reduces OCR in BlCa cells, decreased cell viability and induced apoptosis in a dose and time dependent manner. These results suggest that BlCa cells hijack AR signaling to enhance metabolic activity, promoting cell proliferation and survival; hence targeting this AR downstream vulnerability presents an attractive strategy to limit BlCa.
Subject(s)
Receptors, Androgen , Urinary Bladder Neoplasms , Humans , Receptors, Androgen/genetics , Urinary Bladder , Urinary Bladder Neoplasms/genetics , Epithelial Cells , HypoxiaABSTRACT
BACKGROUND: Aging and diet are risks for metabolic diseases. Bile acid receptor farnesoid X receptor (FXR) knockout (KO) mice develop metabolic liver diseases that progress into cancer as they age, which is accelerated by Western diet (WD) intake. The current study uncovers the molecular signatures for diet and age-linked metabolic liver disease development in an FXR-dependent manner. METHODS: Wild-type (WT) and FXR KO male mice, either on a healthy control diet (CD) or a WD, were euthanized at the ages of 5, 10, or 15 months. Hepatic transcriptomics, liver, serum, and urine metabolomics as well as microbiota were profiled. RESULTS: WD intake facilitated hepatic aging in WT mice. In an FXR-dependent manner, increased inflammation and reduced oxidative phosphorylation were the primary pathways affected by WD and aging. FXR has a role in modulating inflammation and B cell-mediated humoral immunity which was enhanced by aging. Moreover, FXR dictated neuron differentiation, muscle contraction, and cytoskeleton organization in addition to metabolism. There were 654 transcripts commonly altered by diets, ages, and FXR KO, and 76 of them were differentially expressed in human hepatocellular carcinoma (HCC) and healthy livers. Urine metabolites differentiated dietary effects in both genotypes, and serum metabolites clearly separated ages irrespective of diets. Aging and FXR KO commonly affected amino acid metabolism and TCA cycle. Moreover, FXR is essential for colonization of age-related gut microbes. Integrated analyses uncovered metabolites and bacteria linked with hepatic transcripts affected by WD intake, aging, and FXR KO as well as related to HCC patient survival. CONCLUSION: FXR is a target to prevent diet or age-associated metabolic disease. The uncovered metabolites and microbes can be diagnostic markers for metabolic disease.
ABSTRACT
Kaposi sarcoma-associated herpesvirus (KSHV) inflammatory cytokine syndrome (KICS) is a newly described chronic inflammatory disease condition caused by KSHV infection and is characterized by high KSHV viral load and sustained elevations of serum KSHV-encoded IL-6 (vIL-6) and human IL-6 (hIL-6). KICS has significant immortality and possesses greater risks of having other complications, which include malignancies. Although prolonged inflammatory vIL-6 exposure by persistent KSHV infection is expected to have key roles in subsequent disease development, the biological effects of prolonged vIL-6 exposure remain elusive. Using thiol-Linked Alkylation for the Metabolic Sequencing and Cleavage Under Target & Release Using Nuclease analysis, we studied the effect of prolonged vIL-6 exposure in chromatin landscape and resulting cytokine production. The studies showed that prolonged vIL-6 exposure increased Bromodomain containing 4 (BRD4) and histone H3 lysine 27 acetylation co-occupancies on chromatin, and the recruitment sites were frequently co-localized with poised RNAPII with associated enzymes. Increased BRD4 recruitment on promoters was associated with increased and prolonged NF-κB p65 binding after the lipopolysaccharide stimulation. The p65 binding resulted in quicker and sustained transcription bursts from the promoters; this mechanism increased total amounts of hIL-6 and IL-10 in tissue culture. Pretreatment with the BRD4 inhibitor, OTX015, eliminated the enhanced inflammatory cytokine production. These findings suggest that persistent vIL-6 exposure may establish a chromatin landscape favorable for the reactivation of inflammatory responses in monocytes. This epigenetic memory may explain the greater risk of chronic inflammatory disease development in KSHV-infected individuals.
ABSTRACT
The switch between the latency and lytic cycles of Kaposi's sarcoma-associated herpesvirus (KSHV) is accompanied by specific alterations of histone codes. Recently, comprehensive analysis of histone modifications of KSHV showed the deposition of H3K27me3 across the KSHV genome with two specific regions occupied by the heterochromatin marker H3K9me3. Here, we show that knockdown of JMJD2A, an H3K9me3 demethylase, attenuates viral titers, whereas its overexpression increases KSHV reactivation. JMJD2A is localized in regions of latent viral chromosomes that are deficient in the H3K9me3 mark, indicating that JMJD2A may be responsible for the low level of this mark on viral chromatin. The presence of JMJD2A on the latent genome maintains H3K9 in unmethylated form and signals the readiness of specific sets of viral genes to be reactivated. The demethylase activity of JMJD2A is important for KSHV reactivation, because a demethylase-deficient mutant cannot restore the JMJD2A knockdown phenotype. Interestingly, we found that the KSHV encoded K-bZIP associated with JMJD2A, resulting in the inhibition of demethylase activity of JMJD2A both in vivo and in vitro. Inhibition of JMJD2A by K-bZIP is likely due to a physical interaction which blocks substrate accessibility. A consequence of such an inhibition is increasing global levels of H3K9me3 and gene silencing. Consistently, K-bZIP overexpression resulted in a repression of â¼80% of the ≥2-fold differentially regulated genes compared to results for the uninduced control cells. The consequences of K-bZIP targeting JMJD2A during viral replication will be discussed. To our knowledge, this is the first description of a viral product shown to be a potent inhibitor of a host cellular histone demethylase.
Subject(s)
Basic-Leucine Zipper Transcription Factors/metabolism , Herpesvirus 8, Human/pathogenicity , Host-Pathogen Interactions , Jumonji Domain-Containing Histone Demethylases/metabolism , Repressor Proteins/metabolism , Viral Proteins/metabolism , Virus Latency , Virus Replication , Gene Knockdown Techniques , Genetic Complementation Test , Humans , Jumonji Domain-Containing Histone Demethylases/genetics , Protein Binding , Protein Interaction Mapping , Viral LoadABSTRACT
We previously demonstrated that the Trp53-R270H mutation can drive prostate cancer (CaP) initiation using the FVB.129S4 (Trp53tm3Tyj/wt); FVB.129S (Nkx3-1tm3(cre)Mmswt) genetically engineered mouse model (GEM). We now validate this finding in a different model (B6.129S4-Trp53tm3.1Tyj/J mice) and use RNA-sequencing (RNA-Seq) to identify genes which may contribute to Trp53 R270H-mediated prostate carcinogenesis. Wildtype (Trp53WT/WT), heterozygous (Trp53R270H/WT), and homozygous mice (Trp53R270H/R270H) were exposed to 5 Gy irradiation to activate and stabilize p53, and thereby enhance our ability to identify differences in transcriptional activity between the three groups of mice. Mouse prostates were harvested 6 h post-irradiation and processed for histological/immunohistochemistry (IHC) analysis or were snap-frozen for RNA extraction and transcriptome profiling. IHC analyses determined that presence of the Trp53-R270H mutation impacts apoptosis (lower caspase 3 activity) but not cell proliferation (Ki67). RNA-Seq analysis identified 1378 differentially expressed genes, including wildtype p53 target genes (E.g., Cdkn1a, Bax, Bcl2, Kras, Mdm2), p53 gain-of-function (GOF)-related genes (Mgmt, Id4), and CaP-related genes (Cav-1, Raf1, Kras). Further understanding the mechanisms which contribute to prostate carcinogenesis could allow for the development of improved preventive methods, diagnostics, and treatments for CaP.