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iTRAQ-based proteomics analysis of HCMV latency and reactivation in T98G cells. J Virol 2021; 96:e0147621. [PMID: 34730396 DOI: 10.1128/jvi.01476-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) establishes a persistent/latent infection after primary infection, and host factor(s) plays a key role in regulating HCMV infection status. The spread of reactivated HCMV via the hematogenous or neural route usually results in severe diseases in newborns and immunocompromised individuals. As the primary reservoirs in vivo, cells of myeloid lineage have been utilized extensively to study HCMV infection. However, the molecular mechanism of HCMV latency/reactivation in neural cells is still poorly understood. We previously showed that HCMV infected T98G cells maintain a large number of viral genomes and support HCMV reactivation from latency upon cAMP/IBMX treatment. Here we employed iTRAQ-based proteomics to characterize cellular protein changes during HCMV latency and reactivation in T98G cells. A total of 168 differentially expressed proteins (DEPs) were identified, including 89 proteins in latency and 85 proteins in reactivation. Bioinformatics analysis showed that a few biological pathways were associated with HCMV latency or reactivation. Moreover, we validated 16 DEPs by both mRNA and protein expression profiles and further evaluated the effects of ApoE and PI3K pathway on HCMV infection. ApoE knockdown reduced HCMV loads and virus release, whereas overexpressing ApoE hampered HCMV latent infection, indicating a role in HCMV latency establishment/maintenance. Blocking the PI3K pathway by LY294002, a PI3K inhibitor, induced HCMV reactivation from latency in T98G cells. Overall, this comparative proteomic analysis delineates the cellular protein changes during HCMV latency and reactivation and provides a road map to advance our understanding of the mechanism(s) in the context of neural cells. IMPORTANCE Human cytomegalovirus (HCMV) is a highly transmissible beta-herpesvirus that has a prevalence of 60%-90% worldwide. This opportunist pathogen poses a significant threat to newborns and immunosuppressed individuals. One major obstacle for developing effective therapeutics is a poor understanding of HCMV latency/reactivation mechanisms. This study presents, for the first time, a systemic analysis of host cell protein expression changes during HCMV latency establishment and reactivation processes in neural cells. We showed that ApoE was downregulated by HCMV to facilitate latent infection. Also, the proteomic analysis has associated a few PI3K pathway-related proteins with HCMV reactivation. Altogether, this study highlights multiple host proteins and signaling pathways that can be further investigated as potential druggable targets for HCMV-related diseases, especially brain disorders.
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Seifert C, Balz E, Herzog S, Korolev A, Gaßmann S, Paland H, Fink MA, Grube M, Marx S, Jedlitschky G, Tzvetkov MV, Rauch BH, Schroeder HWS, Bien-Möller S. PIM1 Inhibition Affects Glioblastoma Stem Cell Behavior and Kills Glioblastoma Stem-like Cells. Int J Mol Sci 2021; 22:ijms222011126. [PMID: 34681783 PMCID: PMC8541331 DOI: 10.3390/ijms222011126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/09/2021] [Indexed: 12/15/2022] Open
Abstract
Despite comprehensive therapy and extensive research, glioblastoma (GBM) still represents the most aggressive brain tumor in adults. Glioma stem cells (GSCs) are thought to play a major role in tumor progression and resistance of GBM cells to radiochemotherapy. The PIM1 kinase has become a focus in cancer research. We have previously demonstrated that PIM1 is involved in survival of GBM cells and in GBM growth in a mouse model. However, little is known about the importance of PIM1 in cancer stem cells. Here, we report on the role of PIM1 in GBM stem cell behavior and killing. PIM1 inhibition negatively regulates the protein expression of the stem cell markers CD133 and Nestin in GBM cells (LN-18, U-87 MG). In contrast, CD44 and the astrocytic differentiation marker GFAP were up-regulated. Furthermore, PIM1 expression was increased in neurospheres as a model of GBM stem-like cells. Treatment of neurospheres with PIM1 inhibitors (TCS PIM1-1, Quercetagetin, and LY294002) diminished the cell viability associated with reduced DNA synthesis rate, increased caspase 3 activity, decreased PCNA protein expression, and reduced neurosphere formation. Our results indicate that PIM1 affects the glioblastoma stem cell behavior, and its inhibition kills glioblastoma stem-like cells, pointing to PIM1 targeting as a potential anti-glioblastoma therapy.
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Affiliation(s)
- Carolin Seifert
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Ellen Balz
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Susann Herzog
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Anna Korolev
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Sebastian Gaßmann
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Heiko Paland
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Matthias A. Fink
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Markus Grube
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Sascha Marx
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Gabriele Jedlitschky
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Mladen V. Tzvetkov
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
| | - Bernhard H. Rauch
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Pharmacology and Toxicology, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
| | - Henry W. S. Schroeder
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
| | - Sandra Bien-Möller
- Department of Pharmacology, University Medicine Greifswald, 17489 Greifswald, Germany; (C.S.); (E.B.); (S.H.); (A.K.); (S.G.); (H.P.); (M.A.F.); (M.G.); (G.J.); (M.V.T.); (B.H.R.)
- Department of Neurosurgery, University Medicine Greifswald, 17489 Greifswald, Germany; (S.M.); (H.W.S.S.)
- Correspondence: ; Tel.: +49-03834-865646
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Abstract
The N20.1 oligodendroglial cell line, immortalized with SV40 T antigen, simultaneously expresses oligodendroglial markers and glial fibrillary acidic protein (GFAP), an astroglial marker. This study examines the plasticity of N20.1 cells with regard to GFAP expression, and its relationship to expression of SV40 T antigen, p53, and a novel nuclear antigen detected by the A007 monoclonal antibody. Marked changes occur in GFAP levels and cell morphology when N20.1 cells are switched from the permissive temperature (34 degrees C) to the non-permissive temperature (39 degrees C), and with cyclic AMP elevation at 39 degrees C. At 34 degrees C, levels of GFAP are high; when cells are switched to 39 degrees C, GFAP levels decrease significantly, then increase slightly when forskolin is added. At both temperatures, the cells display feathery GFAP immunostaining. When forskolin is added at 39 degrees C, however, cells display bright fibrous GFAP staining in elongated processes. The changes in GFAP were compared to changes in T antigen and p53. As expected, the decrease in T antigen at 39 degrees C was accompanied by movement of p53 from the nucleus to cytoplasm. Total p53 levels did not change, however, and forskolin did not alter the respective distribution or levels of p53 at either temperature. At both temperatures, the cell bodies and processes show internal expression of sulfatide, as demonstrated with the O4, Sulph I, and A007 antibodies. We show, for the first time, abundant nuclear immunoreactivity with the A007 monoclonal antibody in the N20.1 cells. This nuclear reactivity is seen at 34 degrees C, but not at 39 degrees C, similar to p53, and is not detected with the other sulfatide antibodies. Double-label immunostaining shows that the nuclear A007 immunoreactivity is co-localized in nuclear structures with T antigen and p53 at 34 degrees C, but is not found in every nucleus containing these antigens. We conclude that regulation of GFAP expression and morphology in N20.1 cells is dependent on a combination of T antigen expression and level of cAMP and may be related to regulation of p53 and the A007 nuclear antigen.
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Affiliation(s)
- Diane M Studzinski
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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