RÉSUMÉ
Some RNAs such as 28S rRNA, U1 small nuclear RNA (snRNA), and Y RNAs are known to be cleaved during apoptosis. The underlying mechanism, functions, and biological significance of RNA degradation in apoptosis remain elusive. Y RNAs are non-coding RNAs widely conserved from bacteria to mammals, and are major components of Ro ribonucleoprotein (RNP) complexes which contain the 60 kDa Ro protein (SS-A) and the 50 kDa La protein (SS-B). The autoantigenic Ro and La proteins were identified by autoantibodies present in the sera from patients with Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SjS). We previously identified novel, functional small RNAs named AGO-taxis small RNAs (ASRs) that are specifically bound to Argonaute protein 1 (AGO1), which are processed from Y RNAs. Cell-free analysis combined with fractionation methods revealed that the apoptosis-specific biogenesis of ASRs or cleavage of Y RNA was induced by truncation of polypyrimidine tract-binding protein 1 (PTBP1), which is an endoribonuclease inhibitor of Y RNAs by caspase 3. Caspase 3-resistant PTBP1 mutant protected cleavage of Y RNAs in apoptosis induced by staurosporine. Furthermore, caspase 3-resistant PTBP1 mutant knock-in mice showed elevated cytokines, dysregulation of the germinal center formation compared to the wild-type mice at LPS stimulation, and high positivity of antinuclear antibody. Those results suggest that cleavage of Y RNAs or biogenesis of ASR during apoptosis has critical biological functions and their deregulation result in immune dysregulation and the formation of autoantibody, possibly leading to the development of autoimmune diseases.
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BACKGROUND: Transgenic (Tg) mice are widely used in biomedical research, and they are typically generated by injecting transgenic DNA cassettes into pronuclei of one-cell stage zygotes. Such animals often show unreliable expression of the transgenic DNA, one of the major reasons for which is random insertion of the transgenes. We previously developed a method called "pronuclear injection-based targeted transgenesis" (PITT), in which DNA constructs are directed to insert at pre-designated genomic loci. PITT was achieved by pre-installing so called landing pad sequences (such as heterotypic LoxP sites or attP sites) to create seed mice and then injecting Cre recombinase or PhiC31 integrase mRNAs along with a compatible donor plasmid into zygotes derived from the seed mice. PITT and its subsequent version, improved PITT (i-PITT), overcome disadvantages of conventional Tg mice such as lack of consistent and reliable expression of the cassettes among different Tg mouse lines, and the PITT approach is superior in terms of cost and labor. One of the limitations of PITT, particularly using Cre-mRNA, is that the approach cannot be used for insertion of conditional expression cassettes using Cre-LoxP site-specific recombination. This is because the LoxP sites in the donor plasmids intended for achieving conditional expression of the transgene will interfere with the PITT recombination reaction with LoxP sites in the landing pad. RESULTS: To enable the i-PITT method to insert a conditional expression cassette, we modified the approach by simultaneously using PhiC31o and FLPo mRNAs. We demonstrate the strategy by creating a model containing a conditional expression cassette at the Rosa26 locus with an efficiency of 13.7%. We also demonstrate that inclusion of FLPo mRNA excludes the insertion of vector backbones in the founder mice. CONCLUSIONS: Simultaneous use of PhiC31 and FLP in i-PITT approach allows insertion of donor plasmids containing Cre-loxP-based conditional expression cassettes.
Sujet(s)
Génome , Integrases , Souris transgéniques , Animaux , Souris , Integrases/génétique , Integrases/métabolisme , Transgènes , Ciblage de gène/méthodes , Techniques de transfert de gènes , Plasmides/génétique , ARN messager/génétique , ARN messager/métabolisme , Mutagenèse par insertionRÉSUMÉ
Aggressive natural killer cell leukemia (ANKL) is a rare hematological malignancy with a fulminant clinical course. Our previous study revealed that ANKL cells proliferate predominantly in the liver sinusoids and strongly depend on transferrin supplementation. In addition, we demonstrated that liver-resident ANKL cells are sensitive to PPMX-T003, an anti-human transferrin receptor 1 inhibitory antibody, whereas spleen-resident ANKL cells are resistant to transferrin receptor 1 inhibition. However, the microenvironmental factors that regulate the iron dependency of ANKL cells remain unclear. In this study, we first revealed that the anti-neoplastic effect of PPMX-T003 was characterized by DNA double-strand breaks in a DNA replication-dependent manner, similar to conventional cytotoxic agents. We also found that the influx of extracellular amino acids via LAT1 stimulated sensitivity to PPMX-T003. Taken together, we discovered that the amount of extracellular amino acid influx through LAT1 was the key environmental factor determining the iron dependency of ANKL cells via adjustment of their mTOR/Myc activity, which provides a good explanation for the different sensitivity to PPMX-T003 between liver- and spleen-resident ANKL cells, as the liver sinusoid contains abundant amino acids absorbed from the gut.
Sujet(s)
Acides aminés , Fer , Cellules tueuses naturelles , Transporteur-1 d'acides aminés neutres à longue chaîne , Humains , Fer/métabolisme , Cellules tueuses naturelles/métabolisme , Transporteur-1 d'acides aminés neutres à longue chaîne/métabolisme , Acides aminés/métabolisme , Récepteurs à la transferrine/métabolisme , Souris , Animaux , Foie/métabolisme , Foie/anatomopathologieRÉSUMÉ
Lipid-mediated inflammation is involved in the development and malignancy of cancer. We previously demonstrated the existence of a novel oncogenic mechanism utilizing membrane lipids of extracellular vesicles in Epstein-Barr virus (EBV)-positive lymphomas and found that the lipid composition of lymphoma cells is skewed toward ω-3 fatty acids, which are anti-inflammatory lipids, suggesting an alteration in systemic lipid composition. The results showed that arachidonic acid (AA), an inflammatory lipid, was significantly reduced in the infected cells but detected at high levels in the sera of EBV-positive patients lead to the finding of the blockade of extracellular AA influx by downregulating FATP2, a long-chain fatty acid transporter that mainly transports AA in EBV-infected lymphoma cells. Low AA levels in tumor cells induced by downregulation of FATP2 expression confer resistance to ferroptosis and support tumor growth. TCGA data analysis and xenograft models have demonstrated that the axis plays a critical role in several types of cancers, especially poor prognostic cancers, such as glioblastoma and melanoma. Overall, our in vitro, in vivo, in silico, and clinical data suggest that several cancers exert oncogenic activity by maintaining their special lipid composition via extracellular blockade.
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Aggressive natural killer cell leukemia (ANKL) is a rare lymphoid neoplasm frequently associated with Epstein-Barr virus, with a disastrously poor prognosis. Owing to the lack of samples from patients with ANKL and relevant murine models, comprehensive investigation of its pathogenesis including the tumor microenvironment (TME) has been hindered. Here we established 3 xenograft mice derived from patients with ANKL (PDXs), which enabled extensive analysis of tumor cells and their TME. ANKL cells primarily engrafted and proliferated in the hepatic sinusoid. Hepatic ANKL cells were characterized by an enriched Myc-pathway and proliferated faster than those in other organs. Interactome analyses and in vivo CRISPR-Cas9 analyses revealed transferrin (Tf)-transferrin receptor 1 (TfR1) axis as a potential molecular interaction between the liver and ANKL. ANKL cells were rather vulnerable to iron deprivation. PPMX-T003, a humanized anti-TfR1 monoclonal antibody, showed remarkable therapeutic efficacy in a preclinical setting using ANKL-PDXs. These findings indicate that the liver, a noncanonical hematopoietic organ in adults, serves as a principal niche for ANKL and the inhibition of the Tf-TfR1 axis is a promising therapeutic strategy for ANKL.
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Infections à virus Epstein-Barr , Leucémie à grands lymphocytes granuleux , Leucémie prolymphocytaire à cellules T , Animaux , Humains , Souris , Prolifération cellulaire , Infections à virus Epstein-Barr/anatomopathologie , Herpèsvirus humain de type 4 , Leucémie à grands lymphocytes granuleux/anatomopathologie , Foie/anatomopathologie , Transferrines , Microenvironnement tumoralRÉSUMÉ
Extracellular vesicles (EVs) are intercellular communication agents that transfer microRNAs (miRNAs), other non-coding RNAs (ncRNAs), messenger RNAs (mRNAs), proteins, lipids, metabolites, and other molecules from donor cells (e.g., cancer cells) to recipient cells (e.g., stromal cells). In 2007, miRNAs were reported to be abundant among the ncRNAs present in EVs. Since then, many studies have investigated the functions of miRNAs and have attempted to apply these molecules to aid in the diagnosis and treatment of cancer. Research on EVs has expanded, particularly in the field of cancer, because cancer cells heavily secrete EVs. The cargo of these EVs, especially those in small EVs, such as exosomes, is assumed to work cooperatively and significantly in the tumor microenvironment and to promote metastasis. In this review, we first summarize recent studies on EVs in gastrointestinal cancer and highlight studies on human satellite II RNAs, which are a type of ncRNA found in EVs that possess repetitive sequences. Second, since several recent studies have revealed that phospholipids, which are components of EV membranes, play important roles in intercellular communication and the generation of lipid mediators in the tumor microenvironment, we review the reported roles of these molecules and discuss their potential use in the design of new cancer treatments.
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Exosomes , Vésicules extracellulaires , Tumeurs gastro-intestinales , Lymphomes , microARN , Humains , Vésicules extracellulaires/métabolisme , microARN/génétique , microARN/métabolisme , Exosomes/génétique , Exosomes/métabolisme , Tumeurs gastro-intestinales/génétique , Tumeurs gastro-intestinales/métabolisme , Lymphomes/métabolisme , ARN messager/métabolisme , Microenvironnement tumoralRÉSUMÉ
Background and Aims: To examine the roles of microRNAs in the development of colitis, we conducted the RNA-sequencing studies using RNA derived from normal and colitogenic CD4+ T cells. Colitogenic CD4+ T cells demonstrated the increased expression of miR-150. We focused on the involvement of miR-150 in the colitis. Methods: We crossed miR-150 knockout mice and T-cell-specific Rap1KO mice, which is colitis model mice and spontaneously develop the colitis with tubular adenomas in microbiota-dependent manner. Results: MiR-150 silencing completely inhibited the expansion of pathogenic Th17 cells and the development of colitis. Conclusion: MiR-150 is a potential therapeutic target of inflammatory bowel diseases.
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Ceramide levels controlled by the sphingomyelin (SM) cycle have essential roles in cancer cell fate through the regulation of cell proliferation, death, metastasis, and drug resistance. Recent studies suggest that exosomes confer cancer malignancy. However, the relationship between ceramide metabolism and exosome-mediated cancer malignancy is unclear. In this study, we elucidated the role of ceramide metabolism via the SM cycle in exosomes and drug resistance in human leukemia HL-60 and adriamycin-resistant HL-60/ADR cells. HL-60/ADR cells showed significantly increased exosome production and release compared with parental chemosensitive HL-60 cells. In HL-60/ADR cells, increased SM synthase (SMS) activity reduced ceramide levels, although released exosomes exhibited a high ceramide ratio in both HL-60- and HL-60/ADR-derived exosomes. Overexpression of SMS2 but not SMS1 suppressed intracellular ceramide levels and accelerated exosome production and release in HL-60 cells. Notably, HL-60/ADR exosomes conferred cell proliferation and doxorubicin resistance properties to HL-60 cells. Finally, microRNA analysis in HL-60 and HL-60/ADR cells and exosomes showed that miR-484 elevation in HL-60/ADR cells and exosomes was associated with exosome-mediated cell proliferation. This suggests that intracellular ceramide metabolism by SMS2 regulates exosome production and release, leading to acquisition of drug resistance and enhanced cell proliferation in leukemia cells.
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Exosomes , Leucémies , microARN , Céramides/métabolisme , Doxorubicine/pharmacologie , Résistance aux médicaments antinéoplasiques , Exosomes/métabolisme , Humains , microARN/génétique , Sphingomyéline/métabolisme , Transferases (other substituted phosphate groups)RÉSUMÉ
Previous RNA immunoprecipitation followed by proteomic approaches successfully demonstrated that Embryonic Lethal, Abnormal Vision, Drosophila-Like 1 (ELAVL1) interacts with hepatitis B virus (HBV)-derived RNAs. Although ELAVL family proteins stabilize AU-rich element (ARE)-containing mRNAs, their role in HBV transcription remains unclear. This study conducted loss-of-function assays of ELAVL1 for inducible HBV-replicating HepAD38 cells and HBx-overexpressed HepG2 cells. In addition, clinicopathological analyses in primary hepatocellular carcinoma (HCC) surgical samples were also conducted. Lentivirus-mediated short hairpin RNA knockdown of ELAVL1 resulted in a decrease in both viral RNA transcription and production of viral proteins, including HBs and HBx, probably due to RNA stabilization by ELAVL1. Cell growth of HepAD38 cells was more significantly impaired in ELAVL1-knockdown than those in the control group, with or without HBV replication, indicating that ELAVL1 is involved in proliferation by factors other than HBV-derived RNAs. Immunohistochemical analyses of 77 paired HCC surgical specimens demonstrated that diffuse ELAVL1 expression was detected more frequently in HCC tissues (61.0%) than in non-tumor tissues (27.3%). In addition, the abundant expression of ELAVL1 tended to affect postoperative recurrence in HBV-related HCC patients. In conclusion, ELAVL1 contributes not only to HBV replication but also to HCC cell growth. It may be a potent therapeutic target for HBV-related HCC treatment.
Sujet(s)
Carcinome hépatocellulaire , Hépatite B , Tumeurs du foie , Animaux , Carcinome hépatocellulaire/métabolisme , Drosophila/génétique , Cellules HepG2 , Hépatite B/complications , Hépatite B/génétique , Hépatite B/métabolisme , Virus de l'hépatite B/physiologie , Humains , Tumeurs du foie/métabolisme , Protéomique , ARN viral/génétique , ARN viral/métabolisme , Protéines de liaison à l'ARN/génétique , Protéines de liaison à l'ARN/métabolisme , Transactivateurs/métabolisme , Protéines virales régulatrices ou accessoires/métabolisme , Réplication virale/génétiqueRÉSUMÉ
Extracellular vesicles (EVs) including exosomes act as intercellular communicators by transferring protein and microRNA cargoes, yet the role of EV lipids remains unclear. Here, we show that the pro-tumorigenic action of lymphoma-derived EVs is augmented via secreted phospholipase A2 (sPLA2)-driven lipid metabolism. Hydrolysis of EV phospholipids by group X sPLA2, which was induced in macrophages of Epstein-Barr virus (EBV) lymphoma, increased the production of fatty acids, lysophospholipids, and their metabolites. sPLA2-treated EVs were smaller and self-aggregated, showed better uptake, and increased cytokine expression and lipid mediator signaling in tumor-associated macrophages. Pharmacological inhibition of endogenous sPLA2 suppressed lymphoma growth in EBV-infected humanized mice, while treatment with sPLA2-modified EVs reversed this phenotype. Furthermore, sPLA2 expression in human large B cell lymphomas inversely correlated with patient survival. Overall, the sPLA2-mediated EV modification promotes tumor development, highlighting a non-canonical mechanistic action of EVs as an extracellular hydrolytic platform of sPLA2.
Sujet(s)
Infections à virus Epstein-Barr , Vésicules extracellulaires , Lymphome B , Lymphomes , Secretory Phospholipases A2 , Animaux , Herpèsvirus humain de type 4 , Humains , SourisRÉSUMÉ
PD-L1-mediated signaling is one of the major processes that regulate local inflammatory responses in the gut. To date, protective effects against colitis through direct Fc-fused PD-L1 administration or indirect PD-L1 induction by probiotics have been reported. We have previously shown that the anti-HBV drug entecavir (ETV) induces PD-L1 expression in human hepatocytes. In the present study, we investigated whether ETV induces PD-L1 expression in intestinal cells and provides a protective effect against DSS-induced colitis. ETV induced PD-L1 expression in epithelial cells, rather than T and B cells, improving the symptoms of colitis. In the mechanistic analysis, Th17 cell differentiation was inhibited and B cell infiltration into the lamina propria was reduced. In addition, PD-L1 expression was positively correlated with Foxp3 or CSF1-R. In conclusion, ETV upregulated PD-L1 expression in epithelial cells and ameliorated inflammation in DSS-induced colitis. These results suggest that ETV may be a potential therapeutic agent as a PD-L1 enhancer for the treatment of human IBD.
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Antigène CD274 , Colite , Animaux , Antigène CD274/métabolisme , Colite/induit chimiquement , Colite/traitement médicamenteux , Colite/métabolisme , Sulfate dextran/pharmacologie , Guanine/analogues et dérivés , Humains , Souris , Souris de lignée C57BL , Préparations pharmaceutiques/métabolisme , Lymphocytes T régulateurs , Cellules Th17RÉSUMÉ
Acute liver injury (ALI) induced by chemicals or viruses can progress rapidly to acute liver failure (ALF), often resulting in death of patients without liver transplantation. Since liver transplantation is limited due to a paucity of donors, expensive surgical costs, and severe immune rejection, novel therapies are required to treat liver injury. Extracellular vesicles (EVs) are used for cellular communication, carrying RNAs, proteins, and lipids and delivering them intercellularly after being endocytosed by target cells. Recently, it was reported that EVs secreted from human hepatocytes have an ability to modulate the immune responses; however, these roles of EVs secreted from human hepatocytes were studied only with in vitro experiments. In the present study, we evidenced that EVs secreted from human hepatocytes attenuated the CCL4-induced ALI by inhibiting the recruitment of monocytes through downregulation of chemokine receptor in the bone marrow and recruitment of neutrophils through the reduction of C-X-C motif chemokine ligand 1 (CXCL1) and CXCL2 expression levels in the liver.
Sujet(s)
Tétrachloro-méthane/effets indésirables , Vésicules extracellulaires/métabolisme , Hépatocytes/métabolisme , Défaillance hépatique aigüe/induit chimiquement , Animaux , Femelle , Humains , SourisRÉSUMÉ
It is widely accepted that the tumor microenvironment plays an important role in the progression of lymphoid malignancies. Interaction between the tumor and its surrounding immune cells is considered a potential therapeutic target. For example, anti-programmed cell death 1 (PD-1) antibody stimulates the surrounding exhausted immune cells to release PD-1/PD-L1, thereby leading to the regression of PD-L1-positive tumors. Recently, biological phenomena, such as trogocytosis and exosome-mediated transport were demonstrated to be involved in establishing and maintaining the tumor microenvironment. We found that trogocytosis-mediated PD-L1/L2 transfer from tumor cells to monocytes/macrophages is involved in immune dysfunction in classic Hodgkin lymphoma. Exosomes derived from Epstein-Barr virus (EBV)-associated lymphoma cells induce lymphoma tumorigenesis by transferring the EBV-coding microRNAs from the infected cells to macrophages. In this review, we summarized these biological phenomena based on our findings.
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Infections à virus Epstein-Barr , Exosomes , Antigène CD274 , Herpèsvirus humain de type 4 , Humains , Pronostic , Trogocytose , Microenvironnement tumoralRÉSUMÉ
Integrin regulation by Rap1 is indispensable for lymphocyte recirculation. In mice having B-cell-specific Rap1a/b double knockouts (DKO), the number of B cells in lymph nodes decreased to approximately 4% of that of control mice, and B cells were present in the spleen and blood. Upon the immunization with NP-CGG, DKO mice demonstrated the defective GC formation in the spleen, and the reduced NP-specific antibody production. In vitro, Rap1 deficiency impaired the movement of activated B cells along the gradients of chemoattractants known to be critical for their localization in the follicles. Furthermore, B-1a cells were almost completely absent in the peritoneal cavity, spleen and blood of adult DKO mice, and the number of B-cell progenitor/precursor (B-p) were reduced in neonatal and fetal livers. However, DKO B-ps normally proliferated, and differentiated into IgM+ cells in the presence of IL-7. CXCL12-dependent migration of B-ps on the VCAM-1 was severely impaired by Rap1 deficiency. Immunostaining study of fetal livers revealed defects in the co-localization of DKO B-ps and IL-7-producing stromal cells. This study proposes that the profound effects of Rap1-deficiency on humoral responses and B-1a cell generation may be due to or in part caused by impairments of the chemoattractant-dependent positioning and the contact with stromal cells.
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Lymphocytes B/métabolisme , Chimiotaxie des leucocytes , Centre germinatif/métabolisme , Protéines G rap/métabolisme , Protéines G rap1/métabolisme , Animaux , Lymphocytes B/effets des médicaments et des substances chimiques , Lymphocytes B/immunologie , Chimiokine CXCL12/pharmacologie , Chimiotaxie des leucocytes/effets des médicaments et des substances chimiques , Centre germinatif/cytologie , Centre germinatif/effets des médicaments et des substances chimiques , Centre germinatif/immunologie , Immunité humorale , Immunisation , Molécule-1 d'adhérence intercellulaire/métabolisme , Foie/immunologie , Foie/métabolisme , Souris de lignée C57BL , Souris knockout , Précurseurs lymphoïdes B/immunologie , Précurseurs lymphoïdes B/métabolisme , Rate/immunologie , Rate/métabolisme , Molécule-1 d'adhérence des cellules vasculaires/métabolisme , Gammaglobulines/pharmacologie , Protéines G rap/génétique , Protéines G rap1/génétiqueRÉSUMÉ
Research on extracellular vesicles (EVs) has been expanded, especially in the field of cancer. The cargoes in EVs, especially those in small EVs such as exosomes include microRNAs (miRNAs), mRNA, proteins, and lipids, are assumed to work cooperatively in the tumor microenvironment. In 2007, it was reported that miRNAs were abundant among the non-coding RNAs present in exosomes. Since then, many studies have investigated the functions of miRNAs and have tried to apply these molecules to aid in the diagnosis of cancer. Accordingly, many reviews of non-coding RNAs in EVs have been published for miRNAs. This review focuses on relatively new cargoes, covering long noncoding (lnc) RNAs, circular RNAs, and repeat RNAs, among non-coding RNAs. These RNAs, regardless of EV or cell type, have newly emerged due to the innovation of sequencing technology. The poor conservation, low quantity, and technical difficulty in detecting these RNA types have made it difficult to elucidate their functions and expression patterns. We herein summarize a limited number of studies. Although lipids are major components of EVs, current research on EVs focuses on miRNA and protein biology, while the roles of lipids in exosomes have not drawn attention. However, several recent studies revealed that phospholipids, which are components of the EV membrane, play important roles in the intercommunication between cells and in the generation of lipid mediators. Here, we review the reported roles of these molecules, and describe their potential in cancer biology.
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Communication cellulaire/physiologie , Vésicules extracellulaires/métabolisme , Lipides , Tumeurs , ARN non traduit/métabolisme , Animaux , Humains , Tumeurs/métabolisme , Tumeurs/anatomopathologie , Microenvironnement tumoral/physiologieRÉSUMÉ
Epstein-Barr virus (EBV) causes malignant carcinomas including B cell lymphomas accompanied by the systemic inflammation. Previously, we observed that phosphatidylserine (PS)-exposing subset of extracellular vesicles (EVs) secreted from an EBV strain Akata-transformed lymphoma (Akata EVs) convert surrounding phagocytes into tumor-associated macrophages (TAMs) via induction of inflammatory response, which is in part mediated by EBV-derived micro RNAs. However, it is still unclear about EV-carried other potential inflammatory factors associated with TAM formation in EBV lymphomas. To this end, we sought to explore proteomic and phospholipidomic profiles of PS-exposing EVs derived from EBV-transformed lymphomas. Mass spectrometric analysis revealed that several immunomodulatory proteins including integrin αLß2 and fibroblast growth factor 2 (FGF2) were highly expressed in PS-exposing Akata EVs compared with another EBV strain B95-8-transformed lymphoma-derived counterparts which significantly lack TAM-inducing ability. Pharmacological inhibition of either integrin αLß2 or FGF2 hampered cytokine induction in monocytic cultured cells elicited by PS-exposing Akata EVs, suggesting the involvement of these proteins in EV-mediated TAM induction in EBV lymphomas. In addition, phospholipids containing precursors of immunomodulatory lipid mediators were also enriched in PS-exposing Akata EVs compared with B95-8 counterparts. Phospholipidomic analysis of fractionated Akata EVs by density gradient centrifugation further demonstrated that PS-exposing Akata EVs might be identical to certain Akata EVs in low density fractions containing exosomes. Therefore, we concluded that a variety of immunomodulatory cargo molecules in a certain EV subtype are presumably conducive to the development of EBV lymphomas.
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Infections à virus Epstein-Barr/métabolisme , Vésicules extracellulaires/métabolisme , Lymphomes/virologie , Microenvironnement tumoral/physiologie , Prolifération cellulaire/physiologie , Infections à virus Epstein-Barr/virologie , Exosomes/métabolisme , Exosomes/virologie , Herpèsvirus humain de type 4/pathogénicité , Herpèsvirus humain de type 4/physiologie , Humains , Lymphomes/métabolismeRÉSUMÉ
Acute myelogenous leukemia (AML) is one of the major hematological malignancies. In the human genome, several have been found to originate from retroviruses, and some of which are involved in the progression of various cancers. Hence, to investigate whether retroviral-like genes are associated with AML development, we conducted a transcriptome sequencing analysis of 12 retroviral-like genes of 150 AML patients and 32 healthy donor samples, of which RNA sequencing data were obtained from public databases. We found high expression of ERV3-1, an envelope gene of endogenous retrovirus group 3 member 1, in all AML patients examined in this study. In particular, blood and bone marrow cells of the myeloid lineage in AML patients, exhibited higher expression of ERV3-1 than those of the monocytic AML lineage. We also examined the protein expression of ERV3-1 by immunohistochemical analysis and found expression of the ERV3-1 protein in all 12 myeloid-phenotype patients and 7 out of 12 monocytic-phenotype patients, with a particular concentration observed at the membrane of some leukemic cells. Transcriptome analysis further suggested that upregulated ERV3-1 expression may be associated with chromosome 8 trisomy as anomaly was found to be more common among the high expression group than the low expression group. However, this finding was not corroborated by the immunohistochemical data. This discrepancy may have been caused, in part, by the small number of samples analyzed in this study. Although the precise associated molecular mechanisms remain unclear, our results suggest that ERV3-1 may be involved in AML development.
Sujet(s)
Produits du gène env/génétique , Leucémie aigüe myéloïde/génétique , Leucocytes/métabolisme , Monocytes/métabolisme , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Lignage cellulaire , Chromosomes humains de la paire 8/génétique , Femelle , Régulation de l'expression des gènes tumoraux/génétique , Génome humain/génétique , Humains , Leucémie aigüe myéloïde/sang , Leucémie aigüe myéloïde/anatomopathologie , Leucocytes/virologie , Mâle , Adulte d'âge moyen , Monocytes/virologie , Retroviridae/génétique , Trisomie/génétique , Trisomie/anatomopathologieRÉSUMÉ
Fusobacterium nucleatum (Fn) is generally an opportunistic oral pathogen that adheres to mammalian mucosal sites, triggering a host inflammatory response. In general, Fn is normally found within the human oral cavity; however, it was previously reported that Fn is a risk factor for certain respiratory diseases. Surprisingly, this was never fully elucidated. Here, we investigated the virulence potential of heat-killed Fn on primary human tracheal, bronchial, and alveolar epithelial cells. In this study, we measured the secretion of inflammatory- (IL-8 and IL-6), stress- (total heme and hydrogen peroxide), and cell death-related (caspase-1 and caspase-3) signals. We established that the inflammatory response mechanism varies in each epithelial cell type: (1) along tracheal cells, possible Fn adherence would trigger increased heme secretion and regulated inflammatory response; (2) along bronchial cells, potential Fn adherence would simultaneously initiate an increase in secreted H2O2 and inflammatory response (ascribable to decreased secreted heme amounts); and (3) along alveolar cells, putative Fn adherence would instigate the increased secretion of inflammatory responses attributable to a decrease in secreted heme levels. Moreover, regardless of the epithelial cell-specific inflammatory mechanism, we believe these are putative, not harmful. Taken together, we propose that any potential Fn-driven inflammation along the respiratory tract would be initiated by differing epithelial cell-specific inflammatory mechanisms that are collectively dependent on secreted heme.
Sujet(s)
Pneumocytes/métabolisme , Fusobacterium nucleatum/composition chimique , Hème/métabolisme , Température élevée , Pneumocytes/anatomopathologie , Caspase-1/métabolisme , Caspase-3/métabolisme , Humains , Peroxyde d'hydrogène/métabolisme , Inflammation/induit chimiquement , Inflammation/métabolisme , Interleukine-6/métabolisme , Interleukine-8/métabolismeRÉSUMÉ
MicroRNAs (miRNAs), one of small non-coding RNAs, regulate many cell functions through their post-transcriptionally downregulation of target genes. Accumulated studies have revealed that miRNAs are involved in hematopoiesis. In the present study, we investigated effects of miR-669m overexpression on hematopoiesis in mouse in vivo, and found that erythroid differentiation was inhibited by the overexpression. Our bioinformatic analyses showed that candidate targets of miR-669m which are involved in the erythropoiesis inhibition are A-kinase anchoring protein 7 (Akap7) and X-linked Kx blood group (Xk) genes. These two genes were predicted as targets of miR-669m by two different in silico methods and were upregulated in late erythroblasts in a public RNA-seq data, which was confirmed with qPCR. Further, miR-669m suppressed luciferase reporters for 3' untranslated regions of Akap7 and Xk genes, which supports these genes are direct targets of miR-669m. Physiologically, miR-669m was not expressed in the erythroblast. In conclusion, using miR-669m, we found Akap7 and Xk, which may be involved in erythroid differentiation, implying that manipulating these genes could be a therapeutic way for diseases associated with erythropoiesis dysfunction.
Sujet(s)
Protéines d'ancrage aux protéines kinases A/métabolisme , Systèmes de transport d'acides aminés neutres/métabolisme , Différenciation cellulaire , Érythroblastes/cytologie , Érythropoïèse , microARN/génétique , Protéines d'ancrage aux protéines kinases A/génétique , Systèmes de transport d'acides aminés neutres/génétique , Animaux , Érythroblastes/métabolisme , Femelle , Souris , Souris de lignée C57BLRÉSUMÉ
Programmed death-ligand 1 (PD-L1) plays an essential role in tumor cell escape from anti-tumor immunity in various types of cancer, including gastric cancer (GC). The present study investigated the intracellular and membrane-bound expression of PD-L1 in the GC cell lines MKN1, MKN74, KATO III and OCUM-1. Furthermore, soluble PD-L1 (sPD-L1) level in the supernatant of GC cells and the serum of patients with GC and healthy controls was determined by ELISA. Interferon (IFN)-γ treatment of cells resulted in increased cytoplasmic expression of PD-L1 in GC cells in a dose-dependent manner, except for MKN74 cells; however, there was no association between tumor necrosis factor-α treatment and enhanced PD-L1 expression. Concordant with these findings, results from flow cytometry analysis demonstrated that membrane-bound PD-L1 expression was also increased following GC cell treatment with IFN-γ in a dose-dependent manner. In addition, significant sPD-L1 overproduction was observed only in the culture supernatant of OCUM-1 cells. Serum level of sPD-L1 was significantly increased in patients with GC, in particular in stage IV patients, compared with healthy controls. In conclusion, the present study demonstrated that IFN-γ treatment increased the intracellular and membrane-bound PD-L1 expression in GC cells. In addition, sPD-L1 was detected not only in the supernatant of GC cells but also in the serum of patients with GC. Further investigation on the underlying mechanism of regulation of PD-L1 expression and sPD-L1 production is required.