Intrinsic innate immunostimulation by small circRNA vaccines [tumor]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE221085 | GEO | 2023/12/31
REPOSITORIES: GEO
Similar Datasets
Project description:Various RNAs have been shown to elicit innate immunity by activating endosomal PRRs such as Toll-like receptors 3/7/8 (TLR3/7/8), and cytosolic PRRs (e.g., retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated protein 5 (MDA5)). Such innate immunity provides cytokines and co-stimulation signals that are essential for adaptive immunomodulation.
2023-12-31 | GSE221084 | GEO
Project description:The same entry pathway is shared by HBV and HDV. Both viruses attach to hepatocytes via heparansulfate proteoglycan and utilize sodium taurocholate co-transporting polypeptide (NTCP) for a specifc entry. This specific entry step is inhibited by Myrcludex B, a 47-aa lipopeptide myristoylated at the N-terminus. Here we compared the cellular response in the gene expression level triggerred by both viruses. The microarray data shows that HBV infection leads to a silent response but HDV infection triggers high level of innate response such as inteferon-stimulated genes (ISG) expression. Moreover, the response depends on the hepatic cell lines used for infection. Compared to HepG2 cells, HuH7 can not induce ISG even infected by HDV. Abstract of manuscript: Background & aims: Hepatitis B virus (HBV) and D virus (HDV) co-infections cause the most severe form of viral hepatitis. HDV induces an innate immune response, but it is unknown how the host cell senses HDV and if this defense affects HDV replication. We aim to characterize interferon (IFN) activation by HDV, identify the responsible sensor and evaluate the effect of IFN on HDV replication. Methods: HDV and HBV susceptible hepatoma cell lines and primary human hepatocytes (PHH) were used for infection studies. Viral markers and cellular gene expression were analyzed at different time points after infection. Pattern recognition receptors (PRRs) required for HDV-mediated IFN activation and the impact on HDV replication were studied using stable knock-down or overexpression of the PRRs. Results: Microarray analysis revealed that HDV but not HBV infection activated a broad range of interferon stimulated genes (ISGs) in HepG2NTCP cells. HDV strongly activated IFN-β and IFN-λ in cell lines and PHH. HDV induced IFN levels remained unaltered upon RIG-I or TLR3 knock-down, but were almost completely abolished upon MDA5 depletion. Conversely, overexpression of MDA5 but not RIG-I and TLR3 in Huh7.5NTCP cells partially restored ISG induction. During long-term infection, IFN levels gradually diminished in both HepG2NTCP and HepaRGNTCP cell lines. MDA5 depletion had little effect on HDV replication despite dampening HDV-induced IFN response. Moreover, treatment with type I or type III IFNs did not abolish HDV replication. Conclusions: Active replication of HDV induces an IFN-β/λ response, which is predominantly mediated by MDA5. This IFN response and exogenous IFN treatment have only a moderate effect on HDV replication in vitro indicating the adaption of HDV replication to an IFN activated state.
2018-01-30 | GSE109824 | GEO
Project description:The RIG-I-like receptors (RLRs: RIG-I, MDA5 and LGP2) trigger inflammatory and antiviral responses by sensing non-self RNA molecules produced during viral replication. LGP2 regulation of RIG-I and MDA5-dependant type-I interferon signaling is a matter of controversy. Here we show that LGP2 interacts with different components of the RNA silencing machinery. Particularly, we identified a direct protein-protein interaction between LGP2 and interferon-inducible double-stranded RNA-dependent protein kinase activator A (PACT). The LGP2-PACT interaction is mediated by the regulatory C-terminal domain of LGP2 and is necessary for inhibiting the RIG-I- and amplifying the MDA5-responses. We describe a point mutation within LGP2 that disrupts LGP2-PACT interaction and leads to the loss of LGP2 regulatory activity over RIG-I and MDA5. These results provide a model in which PACT-LGP2 interaction regulates RIG-I and MDA5 inflammatory response and allows cellular RNA silencing machinery to coordinate the innate immune response.
2019-10-02 | PXD013191 | Pride
Project description:The RIG-I like receptors (RLRs) RIG-I and MDA5 are cytosolic RNA helicases best characterized as restriction factors for RNA viruses. However, evidence suggests RLRs participate in innate immune recognition of other pathogens, including DNA viruses. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human gammaherpesvirus and the etiological agent of Kaposi's sarcoma and primary effusion lymphoma (PEL). We demonstrate that RIG-I and MDA5 restrict KSHV lytic reactivation in PEL. By performing fRIP-Seq, we define the in vivo RLR substrates and demonstrate that RIG-I and MDA5-mediated restriction is facilitated exclusively by the recognition of host-derived RNAs.
2018-10-11 | GSE116650 | GEO
Project description:Loss of RNA homeostasis underlies numerous neurodegenerative and neuroinflammatory diseases. However, the molecular mechanisms that trigger neuroinflammation are poorly understood. Viral double-stranded RNA (dsRNA) triggers innate immune responses when sensed by host pattern recognition receptors (PRRs) present in all cell types. Here, we report that human neurons intrinsically carry exceptionally high levels of immunostimulatory dsRNAs and identify long 3'UTRs as giving rise to neuronal dsRNA structures. We found that the neuron-enriched ELAVL family of genes (ELAVL2, -3, -4) can increase 1) 3'UTR length, 2) dsRNA load, and 3) activation of dsRNA-sensing PRRs such as MDA5, PKR, and TLR3. In wild-type neurons, neuronal dsRNAs signaled through PRRs to induce tonic production of the antiviral type I interferon. Depleting ELAVL2 in WT neurons led to global shortening of 3'UTR length, reduced immunostimulatory dsRNA levels, and rendered WT neurons susceptible to herpes simplex virus and Zika virus infection. Neurons deficient in ADAR1, a dsRNA-editing enzyme mutated in the neuroinflammatory disorder Aicardi-Goutières syndrome, exhibited intolerably high levels of dsRNA that triggered PRR mediated toxic inflammation and neuronal death. Depleting ELAVL2 in ADAR1 knockout neurons led to prolonged neuron survival by reducing immunostimulatory dsRNA levels. In summary, neurons are specialized cells where PRRs constantly sense ‘self’ dsRNAs to pre-emptively induce protective antiviral immunity, but maintaining RNA homeostasis is paramount to prevent pathological neuroinflammation.
2023-10-20 | GSE214949 | GEO
Project description:Toll like receptor 3 (TLR3) is an endosomal pattern recognition receptor (PRR), recognizing double stranded RNA (dsRNA) as a distinct Pathogen-associated molecular pattern (PAMP) for viral infections. We aim to understand the contribution of TLR3 to the dsRNA response in hepatocytes. The innate immune response of cells of hepatic origin (Huh7, Huh7.5, PH5CH and primary human hepatocytes (PHH)) was analyzed by transcriptome analysis (RNAseq) upon supernatant delivery or transfection of synthetic dsRNA (poly(I:C)). Expression of TLR3 and RIG-I was reconstituted by lentiviral transduction in Huh7 and Huh7.5 cells. Huh7 and Huh7.5 cells, devoid of functional TLR3 expression, did not respond to supernatant delivery of poly(I:C), in contrast to PH5CH and PHH, confirming a high selectivity of this method towards activating TLR3 in all hepatocyte models.
| EGAS00001005147 | EGA
Project description:The important role of IGF-1R in cancers has been well established. Classical model involves IGF-1/2 binding to IGF-1R, following activation of the PI3K/Akt pathway, thereby promoting cell proliferation, apoptosis inhibition and treatment resistance. While IGF-1R has become a promising target for cancer therapy, clinical disclosures subsequently have been less encouraging. The question is whether targeting IGF/IGF-1R still holds therapeutic potential. Here we show a novel mechanism that knockdown IGF-1R surprisingly triggers cytoplasmic viral RNA sensors MDA5 and RIG-1, leading to mitochondrial apoptosis in cancer. We analyzed MDA5 and RIG-1 in the intestinal epithelium of IGF-1R knockdown mice. Igf1r+/- mice demonstrated higher MDA5 and RIG-1 than WT mice. IGF-1R knockdown-triggered MDA5 and RIG-1 was further analyzed in human cancer and normal cells. Increased MDA5 and RIG-1 were clearly seen in the cytoplasm identified by immunofluoresce in the cells silenced IGF-1R. Block off IGF-1R downstream PI3K/Akt did not impact on MDA5 and RIG-1 expression. IGF-1R knockdown-triggered MDA5 and RIG-1 and their signaling pathways were similar to those of viral RNA mimetic poly(I:C) had. IGF-1R knockdown-triggered MDA5 and RIG-1 led to cancer apoptosis through activation of the mitochondrial pathway. In vivo assay, Igf1r+/- mice strongly resisted AOM-induced colonic tumorigenesis through triggering MDA¬5- and RIG-1-mediated apoptosis. Notably, RIG-I and MDA5-mediated proapoptotic signaling pathway is preferential active in cancer cells. These data suggest that targeting IGF-1R-triggered MDA5 and RIG-1 might have therapeutic potential for cancer treatment.
2019-11-30 | GSE122534 | GEO
Project description:Defense against virus infections relies on rapid and massive engagement of cellular proteins with antiviral properties. Germline-encoded pattern recognition receptors (PRRs) sense the presence of pathogens and initiate a signaling cascade leading to the induction of antiviral cytokines, including type-I interferons. IFN-alpha/beta bind to the IFN receptor (IFNAR), initiating signaling that culminates in the expression of interferon-stimulated genes (ISGs). In sum, viral infection triggers the expression of several hundred proteins covering a wide range of biological activities. Among these proteins are PRRs (e.g. RIG-I, MDA5, TLRs), signaling molecules (e.g. MYD88, MAVS), transcription factors (e.g. IRFs, STATs) and proteins with direct antiviral functions (e.g. MX proteins, IFITs), as well as negative regulators of immune responses (e.g. SOCS proteins, DAPK1) that prevent overshooting of immune reactions. ISGs are thus a heterogeneous group of proteins that serve different purposes related to direct antiviral defense and immune regulation.
2019-03-01 | PXD012277 | Pride
Project description:Retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), including RIG-I (encoded by Ddx58) and MDA5 (melanoma-differentiation-associated gene 5, encoded by Ifih1), are crucial for initiating antiviral responses. Endogenous retroviral elements (ERVs) are transposable elements derived from exogenous retrovirus that integrated into the genome. KRAB-associated protein 1 (KAP1) is a master epigenetic suppressor of ERVs, and thereby protects cells from detrimental genome instability. Increased ERV transcripts are sensed by RLRs and trigger innate immune signaling. However, whether KAP1 could directly control RLRs activity remain unclear. Here we show that KAP1 attenuates RNA viral infection induced type I IFNs and facilitates viral replication by inhibiting RIG-I/MDA5 expression in primary peritoneal macrophages of C57BL/6J mice. Kap1 deficiency increased IFN-β expression and inhibited VSV replication in C57BL/6J mice in vivo. Mechanistically, KAP1 binds to the promoter regions of Ddx58 and Ifih1, and promotes the establishment of repressive histone marks in primary peritoneal macrophages of C57BL/6J mice. Concordantly, KAP1 suppresses the expression of RIG-I and MDA5 at transcriptional level in primary peritoneal macrophages of C57BL/6J mice. Our results establish that KAP1 epigenetically suppresses host antiviral responses by direct targeting RIG-1 and MDA5, and thus facilitates the immune escape of RNA viruses.
2021-07-28 | GSE178443 | GEO
Project description:<p>We studied a child with life-threatening and recurrent respiratory tract infections, caused by multiple viruses including rhinovirus, influenza virus, and respiratory syncytial virus (RSV). We identified in her a homozygous missense mutation in IFIH1 that encodes MDA5 by Whole Exome Sequencing. MDA5-deficiency is a novel inborn error of innate immunity that results in impaired dsRNA-sensing, reduced IFN induction, and susceptibility to the common cold virus.</p>
| phs001235 | dbGaP