Reprogramming of microRNA expression via E2F1 downregulation promotes Salmonella infection both in infected and bystander cells.
Ontology highlight
ABSTRACT:
SUBMITTER: Aguilar C
PROVIDER: S-EPMC8184997 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Despite their high degree of genomic similarity, different Salmonella enterica serovars are often associated with very different clinical presentations. In humans, for example, the typhoidal S. enterica serovar Typhi causes typhoid fever, a life-threatening systemic disease. In contrast, the non-typhoidal S. enterica serovar Typhimurium causes self-limiting gastroenteritis. The molecular bases for these different clinical presentations are incompletely understood. The ability to re-program gene expression in host cells is an essential virulence factor for typhoidal and non-typhoidal S. enterica serovars. Here, we have compared the transcriptional profile of cultured epithelial cells infected with S. Typhimurium or S. Typhi. We found that both serovars stimulated distinct transcriptional responses in infected cells that are associated with the stimulation of specific signal transduction pathways. These specific responses were associated with the presence of a distinct repertoire of type III secretion effector proteins. These observations provide major insight into the molecular bases for potential differences in the pathogenic mechanisms of typhoidal and non-typhoidal S. enterica serovars.
| S-EPMC5549772 | biostudies-other
Project description:Human cytomegalovirus(HCMV) infection has been shown to contribute to vascular disease through the induction of angiogenesis. However, the role of microRNA in angiogenesis induced by HCMV infection remains unclear. The present study was thus designed to explore the potential effect of miR-1217 on angiogenesis and to disclose the underlying mechanism in endothelial cells. We found that HCMV infection of endothelial cells(ECs) enhanced expression of miR-217 and reduced SIRT1 and FOXO3A protein level in 24 hours post infection(hpi). Transfection of miR-217 inhibitor not only depressed cellular migration and tube formation induced by HCMV infection, but also enhanced SIRT1 and FOXO3A protein expression. Additionally, luciferase assay confirmed that miR-217 directly targeted FOXO3A mRNA 3`UTR. Furthermore, pretreatment with resveratrol depressed motility and tube formation of HCMV-infected ECs, which could be reversed by SIRT1 siRNA. Similarly, delivery of FOXO3A overexpression lentivirus suppressed proliferative rate, migration and tube formation of HCMV-infected ECs, which reversed by transfection of FOXO3A siRNA. In summary, HCMV infection of endothelial cells induces angiogenesis by both of miR-217/SIRT1 and miR-217/FOXO3A axis.
| S-EPMC3869804 | biostudies-literature
Project description:Non-typhoidal Salmonella (NTS) are highly prevalent food-borne pathogens. Recently, a highly invasive, multi-drug resistant S. Typhimurium, ST313, emerged as a major cause of bacteraemia in children and immunosuppressed adults, however the pathogenic mechanisms remain unclear. Here, we utilize invasive and non-invasive Salmonella strains combined with single-cell RNA-sequencing to study the transcriptome of individual infected and bystander monocyte-derived dendritic cells (MoDCs) implicated in disseminating invasive ST313. Compared with non-invasive Salmonella, ST313 directs a highly heterogeneous innate immune response. Bystander MoDCs exhibit a hyper-activated profile potentially diverting adaptive immunity away from infected cells. MoDCs harbouring invasive Salmonella display higher expression of IL10 and MARCH1 concomitant with lower expression of CD83 to evade adaptive immune detection. Finally, we demonstrate how these mechanisms conjointly restrain MoDC-mediated activation of Salmonella-specific CD4+ T cell clones. Here, we show how invasive ST313 exploits discrete evasion strategies within infected and bystander MoDCs to mediate its dissemination in vivo.
| S-EPMC6242960 | biostudies-literature
Project description:Influenza virus outbreaks remain a serious threat to public health. A greater understanding of how cells targeted by the virus respond to the infection can provide insight into the pathogenesis of disease. Here we examined the transcriptional profile of in vivo-infected and uninfected type 2 alveolar epithelial cells (AEC) in the lungs of influenza virus-infected mice. We show for the first time the unique gene expression profiles induced by the in vivo infection of AEC as well as the transcriptional response of uninfected bystander cells. This work allows us to distinguish the direct and indirect effects of infection at the cellular level. Transcriptome analysis revealed that although directly infected and bystander AEC from infected animals shared many transcriptome changes compared to AEC from uninfected animals, directly infected cells produce more interferon and express lower levels of Wnt signaling-associated transcripts, while concurrently expressing more transcripts associated with cell death pathways, than bystander uninfected AEC. The Wnt signaling pathway was downregulated in both in vivo-infected AEC and in vitro-infected human lung epithelial A549 cells. Wnt signaling did not affect type I and III interferon production by infected A549 cells. Our results reveal unique transcriptional changes that occur within infected AEC and show that influenza virus downregulates Wnt signaling. In light of recent findings that Wnt signaling is essential for lung epithelial stem cells, our findings reveal a mechanism by which influenza virus may affect host lung repair.IMPORTANCE Influenza virus infection remains a major public health problem. Utilizing a recombinant green fluorescent protein-expressing influenza virus, we compared the in vivo transcriptomes of directly infected and uninfected bystander cells from infected mouse lungs and discovered many pathways uniquely regulated in each population. The Wnt signaling pathway was downregulated in directly infected cells and was shown to affect virus but not interferon production. Our study is the first to discern the in vivo transcriptome changes induced by direct viral infection compared to mere exposure to the lung inflammatory milieu and highlight the downregulation of Wnt signaling. This downregulation has important implications for understanding influenza virus pathogenesis, as Wnt signaling is critical for lung epithelial stem cells and lung epithelial cell differentiation. Our findings reveal a mechanism by which influenza virus may affect host lung repair and suggest interventions that prevent damage or accelerate recovery of the lung.
| S-EPMC6189488 | biostudies-literature
Project description:Serine-arginine protein kinase (SRPK) belongs to a class of cell cycle regulating kinases that can phosphorylate proteins containing serine/arginine-Rich (SR) regions. SR proteins are a family of RNA binding phosphoproteins that control both constitutive and alternative pre-mRNA splicing events. However, little is known about their role in non-small cell lung cancer (NSCLC). In the present study, we found that serine-arginine protein kinase 2 (SRPK2) expression was upregulated in NSCLC tissues compared with adjacent normal tissues. Kaplan-Meier curve analyses showed that the overall survival time of NSCLC patients with high SRPK2 expression was shorter than those with low SRPK2 expression. Overexpression of SRPK2 promoted NSCLC cell proliferation and cell cycle arrest, while knockdown of SRPK2 inhibited proliferation and promoted cell cycle arrest in NSCLC cell lines. SRPK2 promoted the transcriptional regulation of E2F1 on downstream cell cycle related genes through phosphorylation of SC35. Xenograft model showed that SRPK2 promoted tumor growth in vivo. SRPK2 phosphorylated SC35 and phosphorylated SC35 activated E2F1 transcription of cyclin-related proteins, thereby promoting the cycle progression of NSCLC. Our findings demonstrated that SRPK2 may be a potential therapeutic target for NSCLC clinical therapy, which plays an important role in the progression of NSCLC.
| S-EPMC6945924 | biostudies-literature
Project description:TNF-related apoptosis-inducing ligand (TRAIL) was initially described to induce apoptosis of tumor cells and/or virally infected cells, although sparing normal cells, and has been implicated in the pathogenesis of HIV disease. We previously identified TRAILshort, a TRAIL splice variant, in HIV-infected patients and characterized it as being a dominant negative ligand to subvert TRAIL-mediated killing. Herein, using single-cell genomics we demonstrate that TRAILshort is produced by HIV-infected cells, as well as by uninfected bystander cells, and that the dominant stimulus which induces TRAILshort production are type I IFNs and TLR7, TLR8, and TLR9 agonists. TRAILshort has a short t1/2 by virtue of containing a PEST domain, which targets the protein toward the ubiquitin proteasome pathway for degradation. Further we show that TRAILshort binds preferentially to TRAIL receptors 1 and 2 with significantly reduced interaction with the decoy TRAIL receptors 3 and 4. Recombinant TRAILshort is sufficient to protect cells against TRAIL-induced killing, whereas immunodepletion of TRAILshort with a specific Ab restores TRAIL sensitivity. Importantly we show that TRAILshort is shed in microvesicles into the cellular microenvironment and therefore confers TRAIL resistance not only on the cell which produces it, but also upon neighboring bystander cells. These results establish a novel paradigm for understanding and overcoming TRAIL resistance, in particular how HIV-infected cells escape immune elimination by the TRAIL:TRAILshort receptor axis.
| S-EPMC5808399 | biostudies-literature
Project description:p130Cas regulates cancer progression by driving tyrosine receptor kinase signaling. Tight regulation of p130Cas expression is necessary for survival, apoptosis, and maintenance of cell motility in various cell types. Several studies revealed that transcriptional and post-translational control of p130Cas are important for maintenance of its expression and activity. To explore novel regulatory mechanisms of p130Cas expression, we studied the effect of microRNAs (miRs) on p130Cas expression in human breast cancer MCF7 cells. Here, we provide experimental evidence that miR-362-3p and miR-329 perform a tumor-suppressive function and their expression is downregulated in human breast cancer. miR-362-3p and miR-329 inhibited cellular proliferation, migration, and invasion, thereby suppressing tumor growth, by downregulating p130Cas. Ectopic expression of p130Cas attenuated the inhibitory effects of the two miRs on tumor progression. Relative expression levels of miR-362-3p/329 and p130Cas between normal and breast cancer correlated inversely; miR-362-3p/329 expression was decreased, whereas that of p130Cas increased in breast cancers. Furthermore, we showed that downregulation of miR-362-3p and miR-329 was caused by differential DNA methylation of miR genes. Enhanced DNA methylation (according to methylation-specific PCR) was responsible for downregulation of miR-362-3p and miR-329 in breast cancer. Taken together, these findings point to a novel role for miR-362-3p and miR-329 as tumor suppressors; the miR-362-3p/miR-329-p130Cas axis seemingly has a crucial role in breast cancer progression. Thus, modulation of miR-362-3p/miR-329 may be a novel therapeutic strategy against breast cancer.
| S-EPMC5072442 | biostudies-literature
Project description:POLD1, the catalytic subunit of DNA Pol δ, plays an important role in DNA synthesis and DNA damage repair, and POLD1 is downregulated in replicative senescence and mediates cell aging. However, the mechanisms of age-related downregulation of POLD1 expression have not been elucidated. In this study, four potential CpG islands in the POLD1 promoter were found, and the methylation levels of the POLD1 promoter were increased in aging 2BS cells, WI-38 cells and peripheral blood lymphocytes, especially at a single site, CpG 36, in CpG island 3. Then, the transcription factor E2F1 was observed to bind to these sites. The binding affinity of E2F1 for the POLD1 promoter was found to show age-related attenuation and was confirmed to be positively regulated by the E2F1 level and negatively regulated by POLD1 promoter methylation. Moreover, cell senescence characteristics were observed in the cells transfected with shRNA-E2F1 and could contribute to the downregulation of POLD1 induced by the E2F1 decline. Collectively, these results indicated that the attenuation of the binding affinity of E2F1 for the POLD1 promoter, mediated by an age-related decline in E2F1 and increased methylation of CpG island 3, downregulates POLD1 expression in aging.
| S-EPMC6588650 | biostudies-literature
Project description:MicroRNAs (miRNAs) fine-tune cellular signaling by regulating expression of signaling proteins, and aberrant expression of miRNAs is observed in many cancers. The tyrosine kinase c-Src is upregulated in various human cancers, but the molecular mechanisms underlying c-Src-mediated tumor progression remain unclear. In previous investigations of miRNA-mediated control of c-Src-related oncogenic pathways, we identified miRNAs that were downregulated in association with c-Src transformation and uncovered the signaling networks by predicting their target genes, which might act cooperatively to control tumor progression. Here, to further elucidate the process of cell transformation driven by c-Src, we analyzed the expression profiles of miRNAs in a doxycycline-inducible Src expression system. We found that miRNA (miR)-129-1-3p was downregulated in the early phase of c-Src-induced cell transformation, and that reexpression of miR-129-1-3p disrupted c-Src-induced cell transformation. In addition, miR-129-1-3p downregulation was tightly associated with tumor progression in human colon cancer cells/tissues. Expression of miR-129-1-3p in human colon cancer cells caused morphological changes and suppressed tumor growth, cell adhesion, and invasion. We also identified c-Src and its critical substrate Fer, and c-Yes, a member of the Src family of kinases, as novel targets of miR-129-1-3p. Furthermore, we found that miR-129-1-3p-mediated regulation of c-Src/Fer and c-Yes is important for controlling cell adhesion and invasion. Downregulation of miR-129-1-3p by early activation of c-Src increases expression of these target genes and synergistically promotes c-Src-related oncogenic signaling. Thus, c-Src-miR-129-1-3p circuits serve as critical triggers for tumor progression in many human cancers that harbor upregulation of c-Src.
| S-EPMC7004518 | biostudies-literature
Project description:Hepatocellular carcinoma (HCC) is one of the most common malignancies and a major cause of cancer-related mortality in the world. MicroRNAs (miRNAs) are small, noncoding RNAs that play essential roles in various stages during cancer progression. The aim of the current study was to elucidate the role of miR-1269 in the pathogenesis of HCC.The expression of miR-1269 in HCC cells and tissues were determined by Real-time PCR analysis. Cell viability, colony formation and anchorage-independent growth ability assays were performed to examine cell proliferative capacity and tumorigenicity. Flow cytometry analysis was conducted to determine cell cycle progression. The expression of p21, CyclinD1, phosphorylated Rb, Rb and FOXO1 were examined by Western blotting analysis. Luciferase assay was used to determine whether FOXO1 is the direct target of miR-1269.miR-1269 was upregulated in HCC cells and tissues. Ectopic miR-1269 expression promoted, but inhibition of miR-1269 reduced, proliferation, tumorigenicity and cell cycle progression of HCC cells. Furthermore, we demonstrated that FOXO1 was a direct target of miR-1269. Suppression of FOXO1 by miR-1269 was associated with dysregulation of p21, cyclin D1, phosphorylated Rb and Ki67 expression, thereby playing an essential role in the growth of HCC cells.Our study indicated that overexpression of miR-1269 promotes cell proliferation in HCC through directly suppressing FOXO1, and functions as an oncomiR in HCC.
| S-EPMC4265494 | biostudies-literature