1
|
Wang X, Fu S, Yu J, Ma F, Zhang L, Wang J, Wang L, Tan Y, Yi H, Wu H, Xu Z. Renal interferon-inducible protein 16 expression is associated with disease activity and prognosis in lupus nephritis. Arthritis Res Ther 2023; 25:112. [PMID: 37393341 PMCID: PMC10314472 DOI: 10.1186/s13075-023-03094-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 06/19/2023] [Indexed: 07/03/2023] Open
Abstract
BACKGROUND Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE). However, the current management of LN remains unsatisfactory due to sneaky symptoms during early stages and lack of reliable predictors of disease progression. METHODS Bioinformatics and machine learning algorithms were initially used to explore the potential biomarkers for LN development. Identified biomarker expression was evaluated by immunohistochemistry (IHC) and multiplex immunofluorescence (IF) in 104 LN patients, 12 diabetic kidney disease (DKD) patients, 12 minimal change disease (MCD) patients, 12 IgA nephropathy (IgAN) patients and 14 normal controls (NC). The association of biomarker expression with clinicopathologic indices and prognosis was analyzed. Gene Set Enrichment Analysis (GSEA) and Gene Set Variation Analysis (GSVA) were utilized to explore potential mechanisms. RESULTS Interferon-inducible protein 16 (IFI16) was identified as a potential biomarker for LN. IFI16 was highly expressed in the kidneys of LN patients compared to those with MCD, DKD, IgAN or NC. IFI16 co-localized with certain renal and inflammatory cells. Glomerular IFI16 expression was correlated with pathological activity indices of LN, while tubulointerstitial IFI16 expression was correlated with pathological chronicity indices. Renal IFI16 expression was positively associated with systemic lupus erythematosus disease activity index (SLEDAI) and serum creatinine while negatively related to baseline eGFR and serum complement C3. Additionally, higher IFI16 expression was closely related to poorer prognosis of LN patients. GSEA and GSVA suggested that IFI16 expression was involved in adaptive immune-related processes of LN. CONCLUSION Renal IFI16 expression is a potential biomarker for disease activity and clinical prognosis in LN patients. Renal IFI16 levels may be used to shed light on predicting the renal response and develop precise therapy for LN.
Collapse
Affiliation(s)
- Xueyao Wang
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Shaojie Fu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Jinyu Yu
- Department of Renal Pathology, The First Hospital of Jilin University, Changchun, China
| | - Fuzhe Ma
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Lihong Zhang
- Department of Pathology, Basic Medical College of Jilin University, Changchun, China
| | - Jiahui Wang
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Luyu Wang
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Yue Tan
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
| | - Huanfa Yi
- Central Laboratory, The First Hospital of Jilin University, Changchun, China
| | - Hao Wu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China.
| | - Zhonggao Xu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China.
| |
Collapse
|
2
|
Łasut-Szyszka B, Rusin M. The Wheel of p53 Helps to Drive the Immune System. Int J Mol Sci 2023; 24:ijms24087645. [PMID: 37108808 PMCID: PMC10143509 DOI: 10.3390/ijms24087645] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
The p53 tumor suppressor protein is best known as an inhibitor of the cell cycle and an inducer of apoptosis. Unexpectedly, these functions of p53 are not required for its tumor suppressive activity in animal models. High-throughput transcriptomic investigations as well as individual studies have demonstrated that p53 stimulates expression of many genes involved in immunity. Probably to interfere with its immunostimulatory role, many viruses code for proteins that inactivate p53. Judging by the activities of immunity-related p53-regulated genes it can be concluded that p53 is involved in detection of danger signals, inflammasome formation and activation, antigen presentation, activation of natural killer cells and other effectors of immunity, stimulation of interferon production, direct inhibition of virus replication, secretion of extracellular signaling molecules, production of antibacterial proteins, negative feedback loops in immunity-related signaling pathways, and immunologic tolerance. Many of these p53 functions have barely been studied and require further, more detailed investigations. Some of them appear to be cell-type specific. The results of transcriptomic studies have generated many new hypotheses on the mechanisms utilized by p53 to impact on the immune system. In the future, these mechanisms may be harnessed to fight cancer and infectious diseases.
Collapse
Affiliation(s)
- Barbara Łasut-Szyszka
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101 Gliwice, Poland
| | - Marek Rusin
- Center for Translational Research and Molecular Biology of Cancer, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, 44-101 Gliwice, Poland
| |
Collapse
|
3
|
Choubey D. Cytosolic DNA sensor IFI16 proteins: Potential molecular integrators of interactions among the aging hallmarks. Ageing Res Rev 2022; 82:101765. [PMID: 36270606 DOI: 10.1016/j.arr.2022.101765] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/11/2022] [Accepted: 10/16/2022] [Indexed: 01/31/2023]
Abstract
Cellular changes that are linked to aging in humans include genomic instability, telomere attrition, epigenetic alterations, mitochondrial dysfunction, cellular senescence, and altered intercellular communications. The extent of the changes in these aging hallmarks and their interactions with each other are part of the human aging. However, the molecular mechanisms through which the aging hallmarks interact with each other remain unclear. Studies have indicated a potential role for the type I interferon (IFN) and p53-inducible IFI16 proteins in interactions with the aging hallmarks. The IFI16 proteins are members of the PYHIN protein family. Proteins in the family share a DNA-binding domain (the HIN domain) and a protein-protein interaction pyrin domain (PYD). IFI16 proteins are needed for cytosolic DNA-induced activation of the cGAS-STING pathway for type I IFN (IFN-β) expression. The pathway plays an important role in aging-related inflammation (inflammaging). Further, increased levels of the IFI16 proteins potentiate the cell growth inhibitory functions of the p53 and pRb tumor suppressors proteins. Moreover, IFI16 proteins are needed for most aging hallmarks. Therefore, here we discuss how an improved understanding of the role of the IFI16 proteins in integration of the aging hallmarks has potential to improve the human health and lifespan.
Collapse
Affiliation(s)
- Divaker Choubey
- Department of Environmental & Public Health Sciences University of Cincinnati, 160 Panzeca Way, P.O. Box 670056, Cincinnati, OH 45267, USA.
| |
Collapse
|
4
|
Justice JL, Cristea IM. Nuclear antiviral innate responses at the intersection of DNA sensing and DNA repair. Trends Microbiol 2022; 30:1056-1071. [PMID: 35641341 PMCID: PMC9560981 DOI: 10.1016/j.tim.2022.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 01/13/2023]
Abstract
The coevolution of vertebrate and mammalian hosts with DNA viruses has driven the ability of host cells to distinguish viral from cellular DNA in the nucleus to induce intrinsic immune responses. Concomitant viral mechanisms have arisen to inhibit DNA sensing. At this virus-host interface, emerging evidence links cytokine responses and cellular homeostasis pathways, particularly the DNA damage response (DDR). Nuclear DNA sensors, such as the interferon (IFN)-γ inducible protein 16 (IFI16), functionally intersect with the DDR regulators ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK). Here, we discuss accumulating knowledge for the DDR-innate immunity signaling axis. Through the lens of this infection-driven signaling axis, we present host and viral molecular strategies acquired to regulate autoinflammation and antiviral responses.
Collapse
Affiliation(s)
- Joshua L Justice
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA.
| |
Collapse
|
5
|
Borucka J, Sterzyńska K, Kaźmierczak D, Świerczewska M, Nowacka M, Wojtowicz K, Klejewski A, Nowicki M, Zabel M, Ramlau R, Januchowski R. The significance of interferon gamma inducible protein 16 (IFI16) expression in drug resistant ovarian cancer cell lines. Biomed Pharmacother 2022; 150:113036. [PMID: 35489285 DOI: 10.1016/j.biopha.2022.113036] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Inherent or developed during treatment drug resistance is the main reason for the low effectiveness of chemotherapy in ovarian cancer. IFI16 is a cytoplasmic/nuclear protein involved in response to virus's infection and cell cycle arrest associated with the cellular senescence. METHODS Here we performed a detailed IFI16 expression analysis in ovarian cancer cell lines sensitive (A2780) and resistant to doxorubicin (DOX) (A2780DR1 and A2780DR2) and paclitaxel (PAC) (A2780PR1). IFI16 mRNA level, protein level in the nuclear and cytoplasmic fraction (Western blot analysis), the protein expression in cancer cells and nuclei (immunofluorescence analysis) and cancer patient lesions (immunohistochemistry) were performed in this study. RESULTS We observed upregulation of IFI16 expression in drug resistant cell lines with dominant cytoplasmic localization in DOX-resistant cell lines and nuclear one in the PAC-resistant cell line. The most abundantly overexpressed isoforms of IFI16 were IFI16A and IFI16C. Finally, an analysis of a histological type of ovarian cancer (immunohistochemistry) showed expression in serous ovarian cancer. CONCLUSIONS Expression of IFI16 in drug-resistant cell lines suggests its role in drug resistance development in ovarian cancer. Expression in serous ovarian cancer suggests its role in the pathogenesis of this histological type.
Collapse
Affiliation(s)
- Justyna Borucka
- Department of Oncology, Poznan University of Medical Sciences, Szamarzewskiego 82/84, 60-569 Poznań, Poland
| | - Karolina Sterzyńska
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Dominika Kaźmierczak
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Monika Świerczewska
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Marta Nowacka
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Karolina Wojtowicz
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Andrzej Klejewski
- Department of Nursing, Poznan University of Medical Sciences, Smoluchowskiego 11 St., 60-179 Poznań, Poland; Department of Obstetrics and Women's Diseases, Poznan University of Medical Sciences, Polna 33 St, 60-535 Poznań, Poland
| | - Michał Nowicki
- Department of Histology and Embryology, Poznan University of Medical Sciences, Święcickiego 6 St., 61-781 Poznań, Poland
| | - Maciej Zabel
- Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, Wroclaw, Poland; Department of Anatomy and Histology, Collegium Medicum, University of Zielona Gora, Zyty 28 St, 65-046 Zielona Gora, Poland
| | - Rodryg Ramlau
- Department of Oncology, Poznan University of Medical Sciences, Szamarzewskiego 82/84, 60-569 Poznań, Poland
| | - Radosław Januchowski
- Department of Anatomy and Histology, Collegium Medicum, University of Zielona Gora, Zyty 28 St, 65-046 Zielona Gora, Poland.
| |
Collapse
|
6
|
Ghosh M, Saha S, Bettke J, Nagar R, Parrales A, Iwakuma T, van der Velden AWM, Martinez LA. Mutant p53 suppresses innate immune signaling to promote tumorigenesis. Cancer Cell 2021; 39:494-508.e5. [PMID: 33545063 PMCID: PMC8044023 DOI: 10.1016/j.ccell.2021.01.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 12/04/2020] [Accepted: 01/08/2021] [Indexed: 12/27/2022]
Abstract
Mutant p53 (mtp53) proteins can exert cancer-promoting gain-of-function activities. We report a mechanism by which mtp53 suppresses both cell-autonomous and non-cell-autonomous signaling to promote cancer cell survival and evasion of tumor immune surveillance. Mtp53 interferes with the function of the cytoplasmic DNA sensing machinery, cGAS-STING-TBK1-IRF3, that activates the innate immune response. Mtp53, but not wild-type p53, binds to TANK-binding protein kinase 1 (TBK1) and prevents the formation of a trimeric complex between TBK1, STING, and IRF3, which is required for activation, nuclear translocation, and transcriptional activity of IRF3. Inactivation of innate immune signaling by mtp53 alters cytokine production, resulting in immune evasion. Restoring TBK1 signaling is sufficient to bypass mtp53 and lead to restored immune cell function and cancer cell eradication. This work is of translational interest because therapeutic approaches that restore TBK1 function could potentially reactivate immune surveillance and eliminate mtp53 tumors.
Collapse
Affiliation(s)
- Monisankar Ghosh
- Stony Brook Cancer Center, Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11790, USA
| | - Suchandrima Saha
- Stony Brook Cancer Center, Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11790, USA
| | - Julie Bettke
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY 11790, USA
| | - Rachana Nagar
- Stony Brook Cancer Center, Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11790, USA
| | - Alejandro Parrales
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Tomoo Iwakuma
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | - Luis A Martinez
- Stony Brook Cancer Center, Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11790, USA.
| |
Collapse
|
7
|
Zhang F, Yuan Y, Ma F. Function and Regulation of Nuclear DNA Sensors During Viral Infection and Tumorigenesis. Front Immunol 2021; 11:624556. [PMID: 33505405 PMCID: PMC7829187 DOI: 10.3389/fimmu.2020.624556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022] Open
Abstract
IFI16, hnRNPA2B1, and nuclear cGAS are nuclear-located DNA sensors that play important roles in initiating host antiviral immunity and modulating tumorigenesis. IFI16 triggers innate antiviral immunity, inflammasome, and suppresses tumorigenesis by recognizing double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), damaged nuclear DNA, or cooperatively interacting with multiple tumor suppressors such as p53 and BRCA1. hnRNPA2B1 initiates interferon (IFN)-α/β production and enhances STING-dependent cytosolic antiviral signaling by directly binding viral dsDNA from invaded viruses and facilitating N6 -methyladenosine (m6A) modification of cGAS, IFI16, and STING mRNAs. Nuclear cGAS is recruited to double-stranded breaks (DSBs), suppresses DNA repair, and promotes tumorigenesis. This review briefly describes the nuclear functions of IFI16, hnRNPA2B1, and cGAS, and summarizes the transcriptional, post-transcriptional, and post-translational regulation of these nuclear DNA sensors.
Collapse
Affiliation(s)
- Fan Zhang
- Key Laboratory of Synthetic Biology Regulatory Elements, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China
| | - Yi Yuan
- Key Laboratory of Synthetic Biology Regulatory Elements, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China.,Department of Laboratory Medicine, Shanghai Tongji Hospital, School of Medicine of Tongji University, Shanghai, China
| | - Feng Ma
- Key Laboratory of Synthetic Biology Regulatory Elements, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.,Suzhou Institute of Systems Medicine, Suzhou, China
| |
Collapse
|
8
|
Synergistic activation of p53 by actinomycin D and nutlin-3a is associated with the upregulation of crucial regulators and effectors of innate immunity. Cell Signal 2020; 69:109552. [PMID: 32032660 PMCID: PMC7126238 DOI: 10.1016/j.cellsig.2020.109552] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/31/2020] [Accepted: 01/31/2020] [Indexed: 02/02/2023]
Abstract
Actinomycin D and nutlin-3a (A + N) activate p53, partly through induction of phosphorylation on Ser392. The death of A549 cells induced by A + N morphologically resembles inflammation-inducing pyroptosis - cell destruction triggered by activated caspase-1. The treatment with A + N (or camptothecin) strongly upregulated caspase-1 and its two activators: IFI16 and NLRP1, however, caspase-1 activation was not detected. A549 cells may have been primed for pyroptosis, with the absence of a crucial trigger. The investigation of additional innate immunity elements revealed that A + N (or camptothecin) stimulated the expression of NLRX1, STING (stimulator of interferon genes) and two antiviral proteins, IFIT1 and IFIT3. IFI16 and caspase-1 are coded by p53-regulated genes which led us to investigate regulation of NLRP1, NLRX1, STING, IFIT1 and IFIT3 in p53-dependent mode. The upregulation of NLRP1, NLRX1 and STING was attenuated in p53 knockdown cells. The upsurge of the examined genes, and activation of p53, was inhibited by C16, an inhibitor of PKR kinase. PKR was tested due to its ability to phosphorylate p53 on Ser392. Surprisingly, C16 was active even in PKR knockdown cells. The ability of C16 to prevent activation of p53 and expression of innate immunity genes may be the source of its strong anti-inflammatory action. Moreover, cells exposed to A + N can influence neighboring cells in paracrine fashion, for instance, they shed ectodomain of COL17A1 protein and induce, in p53-dependent mode, the expression of gene for interleukin-7. Further, the activation of p53 also spurred the expression of SOCS1, an inhibitor of interferon triggered STAT1-dependent signaling. We conclude that, stimulation of p53 primes cells for the production of interferons (through upregulation of STING), and may activate negative-feedback within this signaling system by enhancing the production of SOCS1. Actinomycin D and nutlin-3a strongly and synergistically activate p53 protein Strongly activated p53 promotes expression of innate immunity genes Strong activation of innate immunity genes can be prevented by C16 compound By inducing SOCS1 protein p53 can prevent overactivation of interferon signaling Strongly activated p53 can send signal to nearby immune cells through interleukin-7
Collapse
|
9
|
Piccaluga PP, Navari M, Visani A, Rigotti F, Agostinelli C, Righi S, Diani E, Ligozzi M, Carelli M, Ponti C, Bon I, Zipeto D, Landolfo S, Gibellini D. Interferon gamma inducible protein 16 (IFI16) expression is reduced in mantle cell lymphoma. Heliyon 2019; 5:e02643. [PMID: 31840115 PMCID: PMC6893061 DOI: 10.1016/j.heliyon.2019.e02643] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/12/2019] [Accepted: 10/09/2019] [Indexed: 11/05/2022] Open
Abstract
IFI16, member of the IFN-inducible PYHIN-200 gene family, modulates proliferation, survival and differentiation of different cell lineages. In particular, IFI16 expression, which is regulated during the differentiation of B cells, was recently studied in B-CLL as well. Here, we compared IFI16 expression in several lymphomas including Burkitt lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, marginal zone lymphoma and mantle cell lymphoma with respect to normal cell counterparts. We observed that IFI16 expression was significantly deregulated only in mantle cell lymphoma (p < 0.05). Notably, IFI16 was associated with the expression of genes involved in interferon response, cell cycle, cell death and proliferation and, interestingly, lipid and glucose metabolism, suggesting that IFI16 deregulation might be associated with relevant changes in cell biology. In our group of mantle cell lymphoma samples a correlation between patient survival and IFI16 expression was not detected even though mantle cell lymphoma prognosis is known to be associated with cell proliferation. Altogether, these results suggest a complex relationship between IFI16 expression and MCL which needs to be analyzed in further studies.
Collapse
Affiliation(s)
- Pier Paolo Piccaluga
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy.,Istituto Euro-Mediterraneo di Scienza e Tecnologia (IEMEST) Palermo, Italy.,Department of Pathology, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Mohsen Navari
- Department of Medical Biotechnology, School of Paramedical Sciences, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.,Research Center of Advanced Technologies in Medicine, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.,Bioinformatics Research Group, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Axel Visani
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Flavia Rigotti
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Claudio Agostinelli
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Simona Righi
- Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy
| | - Erica Diani
- Department of Diagnostic and Public Health, Unit of Microbiology, University of Verona, Verona, Italy
| | - Marco Ligozzi
- Department of Diagnostic and Public Health, Unit of Microbiology, University of Verona, Verona, Italy
| | - Maria Carelli
- Department of Diagnostic and Public Health, Unit of Microbiology, University of Verona, Verona, Italy
| | - Cristina Ponti
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Isabella Bon
- Department of Experimental, Diagnostic, and Specialty Medicine, Microbiology Unit, University of Bologna, Bologna, Italy
| | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Santo Landolfo
- Department of Public Health and Microbiology, University of Turin, Turin, Italy
| | - Davide Gibellini
- Department of Diagnostic and Public Health, Unit of Microbiology, University of Verona, Verona, Italy
| |
Collapse
|
10
|
Overexpression of absent in melanoma 2 in oral squamous cell carcinoma contributes to tumor progression. Biochem Biophys Res Commun 2019; 509:82-88. [DOI: 10.1016/j.bbrc.2018.12.066] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 12/09/2018] [Accepted: 12/10/2018] [Indexed: 12/30/2022]
|
11
|
Hao B, Xiao Y, Song F, Long X, Huang J, Tian M, Deng S, Wu Q. Metformin-induced activation of AMPK inhibits the proliferation and migration of human aortic smooth muscle cells through upregulation of p53 and IFI16. Int J Mol Med 2017; 41:1365-1376. [PMID: 29286156 PMCID: PMC5819901 DOI: 10.3892/ijmm.2017.3346] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/07/2017] [Indexed: 11/28/2022] Open
Abstract
The proliferation and migration of vascular smooth muscle cells are significant in the development and progression of atherosclerosis and plaque rupture. Metformin is a widely used antidiabetic drug, which has been reported to inhibit cell growth and migration. The antiproliferative and antimigratory effects of metformin have been attributed to 5′ adenosine monophosphate-activated protein kinase (AMPK) activation. The purpose of the present study was to investigate the effects of metformin on primary human aortic muscle cells (HASMCs) in vitro and to clarify the underlying mechanism. We investigated the effectiveness of metformin in inhibiting the proliferation and migration of HASMCs in vitro using RNA extraction and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), cell number counting, cell viability assay, cell cycle assay and cell migration assay. Through transfection with small interfering (si)RNA targeting p53 and interferon-inducible protein 16 (IFI16), the roles of p53 and IFI16 in these processes were evaluated. The present study demonstrated that p53, IFI16 and AMPK were upregulated in senescent primary HASMCs, which exhibited a decrease in proliferation and migration. In addition, metformin was able to activate p53, IFI16 and AMPK, in order to inhibit proliferation and migration of HASMCs. Furthermore, siRNA-mediated knockdown of p53 and IFI16 attenuated AMPK activation and reversed the suppressive effects of metformin. Notably, in response to metformin, the activation of AMPK was not observed in p53- and IFI16-silenced HASMCs. These results indicated that metformin-induced activation of AMPK suppresses the proliferation and migration of HASMCs by upregulating p53 and IFI16. These findings suggested that metformin may have potential use in the treatment of atherosclerosis.
Collapse
Affiliation(s)
- Biao Hao
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Yan Xiao
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Fang Song
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Xiangshu Long
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Jing Huang
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Maobo Tian
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Shiyan Deng
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| | - Qiang Wu
- Department of Cardiology, The Affiliated People's Hospital of Guizhou Medical University, Guiyang, Guizhou 550002, P.R. China
| |
Collapse
|
12
|
Shrestha D, Kim N, Song K. Stathmin/Op18 depletion induces genomic instability and leads to premature senescence in human normal fibroblasts. J Cell Biochem 2017; 119:2381-2395. [PMID: 28885720 DOI: 10.1002/jcb.26401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 08/30/2017] [Indexed: 12/28/2022]
Abstract
Stathmin/oncoprotein18 regulates microtubule dynamics and participates in mitotic entry and exit. We isolated stathmin as a physically interacting partner of KIFC1, a minus-end-directed kinesin functioning in bipolar spindle formation and maintenance. We found that stathmin depletion leads to multipolar spindle formation in IMR-90 normal human fibroblasts. Stathmin-depleted IMR-90 cells showed early mitotic delay but managed to undergo chromosome segregation by forming multiple poles or pseudo-bipoles. Consistent with these observations, lagging chromosomes, and micronuclei were elevated in stathmin-depleted IMR-90 cells, demonstrating that stathmin is essential for maintaining genomic stability during mitosis in human cells. Genomic instability induced by stathmin depletion led to premature senescence without any indication of cell death in normal IMR-90 cells. Double knock-down of both stathmin and p53 also did not induce cell death in IMR-90 cells, while the stathmin knock-down triggered apoptosis in p53-proficient human lung adenocarcinoma cells. Our results suggest that stathmin is essential in bipolar spindle formation to maintain genomic stability during mitosis, and the depletion of stathmin prevents the initiation of chromosome instability by inducing senescence in human normal fibroblasts.
Collapse
Affiliation(s)
- Deepmala Shrestha
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Namil Kim
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Kiwon Song
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| |
Collapse
|
13
|
Piccaluga PP, Agostinelli C, Righi S, Ciccone M, Re MC, Musumeci G, Diani E, Signoretto C, Bon I, Piccin O, Cuneo A, Tripodo C, Ponti C, Zipeto D, Landolfo S, Gibellini D. IFI16 reduced expression is correlated with unfavorable outcome in chronic lymphocytic leukemia. APMIS 2017; 125:511-522. [PMID: 28517553 DOI: 10.1111/apm.12692] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 02/08/2017] [Indexed: 01/05/2023]
Abstract
Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Its clinical course is typically indolent; however, based on a series of pathobiological, clinical, genetic, and phenotypic parameters, patient survival varies from less than 5 to more than 20 years. In this paper, we show for the first time that the expression of the interferon-inducible DNA sensor IFI16, a member of the PYHIN protein family involved in proliferation inhibition and apoptosis regulation, is associated with the clinical outcome in CLL. We studied 99 CLLs cases by immunohistochemistry and 10 CLLs cases by gene expression profiling. We found quite variable degrees of IFI16 expression among CLLs cases. Noteworthy, we observed that a reduced IFI16 expression was associated with a very poor survival, but only in cases with ZAP70/CD38 expression. Furthermore, we found that IFI16 expression was associated with a specific gene expression signature. As IFI16 can be easily detected by immunohistochemistry or flow cytometry, it may become a part of phenotypic screening in CLL patients if its prognostic role is confirmed in independent series.
Collapse
Affiliation(s)
- Pier Paolo Piccaluga
- Department of Experimental, Diagnostic, and Specialty Medicine; University of Bologna; Bologna Italy
- Section of Genomics and Personalized Medicine; Istituto Euro-Mediterraneo di Scienza e Tecnologia (IEMEST); Palermo Italy
| | - Claudio Agostinelli
- Department of Experimental, Diagnostic, and Specialty Medicine; University of Bologna; Bologna Italy
| | - Simona Righi
- Department of Experimental, Diagnostic, and Specialty Medicine; University of Bologna; Bologna Italy
| | - Maria Ciccone
- Department of Biomedical Sciences; Hematology Section; S. Anna Hospital; University of Ferrara; Ferrara Italy
| | - Maria Carla Re
- Department of Experimental, Diagnostic, and Specialty Medicine; Microbiology Unit; University of Bologna; Bologna Italy
| | - Giuseppina Musumeci
- Department of Experimental, Diagnostic, and Specialty Medicine; Microbiology Unit; University of Bologna; Bologna Italy
| | - Erica Diani
- Department of Diagnostic and Public Health; Unit of Microbiology; University of Verona; Verona Italy
| | - Caterina Signoretto
- Department of Diagnostic and Public Health; Unit of Microbiology; University of Verona; Verona Italy
| | - Isabella Bon
- Department of Experimental, Diagnostic, and Specialty Medicine; Microbiology Unit; University of Bologna; Bologna Italy
| | - Ottavio Piccin
- Department of Experimental, Diagnostic, and Specialty Medicine; Otolaryngology Unit; University of Bologna; Bologna Italy
| | - Antonio Cuneo
- Department of Biomedical Sciences; Hematology Section; S. Anna Hospital; University of Ferrara; Ferrara Italy
| | - Claudio Tripodo
- Section of Genomics and Personalized Medicine; Istituto Euro-Mediterraneo di Scienza e Tecnologia (IEMEST); Palermo Italy
- Department of Human Pathology; University of Palermo; Palermo Italy
| | - Cristina Ponti
- Department of Life Sciences; University of Trieste; Trieste Italy
| | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences; University of Verona; Verona Italy
| | - Santo Landolfo
- Department of Public Health and Microbiology; University of Turin; Turin Italy
| | - Davide Gibellini
- Department of Diagnostic and Public Health; Unit of Microbiology; University of Verona; Verona Italy
| |
Collapse
|
14
|
Choubey D, Panchanathan R. IFI16, an amplifier of DNA-damage response: Role in cellular senescence and aging-associated inflammatory diseases. Ageing Res Rev 2016; 28:27-36. [PMID: 27063514 DOI: 10.1016/j.arr.2016.04.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/30/2016] [Accepted: 04/04/2016] [Indexed: 12/22/2022]
Abstract
DNA-damage induces a DNA-damage response (DDR) in mammalian cells. The response, depending upon the cell-type and the extent of DNA-damage, ultimately results in cell death or cellular senescence. DDR-induced signaling in cells activates the ATM-p53 and ATM-IKKα/β-interferon (IFN)-β signaling pathways, thus leading to an induction of the p53 and IFN-inducible IFI16 gene. Further, upon DNA-damage, DNA accumulates in the cytoplasm, thereby inducing the IFI16 protein and STING-dependent IFN-β production and activation of the IFI16 inflammasome, resulting in the production of proinflammatory cytokines (e.g., IL-1β and IL-18). Increased expression of IFI16 protein in a variety of cell-types promotes cellular senescence. However, reduced expression of IFI16 in cells promotes cell proliferation. Because expression of the IFI16 gene is induced by activation of DNA-damage response in cells and increased levels of IFI16 protein in cells potentiate the p53-mediated transcriptional activation of genes and p53 and pRb-mediated cell cycle arrest, we discuss how an improved understanding of the role of IFI16 protein in cellular senescence and associated inflammatory secretory phenotype is likely to identify the molecular mechanisms that contribute to the development of aging-associated human inflammatory diseases and a failure to cancer therapy.
Collapse
Affiliation(s)
- Divaker Choubey
- Cincinnati VA Medical Center, 3200 Vine Street, Cincinnati, OH 45220, United States; Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, P.O. Box-670056, Cincinnati, OH 45267, United States.
| | - Ravichandran Panchanathan
- Cincinnati VA Medical Center, 3200 Vine Street, Cincinnati, OH 45220, United States; Department of Environmental Health, University of Cincinnati, 160 Panzeca Way, P.O. Box-670056, Cincinnati, OH 45267, United States
| |
Collapse
|
15
|
Abstract
The predominant function of the tumor suppressor p53 is transcriptional regulation. It is generally accepted that p53-dependent transcriptional activation occurs by binding to a specific recognition site in promoters of target genes. Additionally, several models for p53-dependent transcriptional repression have been postulated. Here, we evaluate these models based on a computational meta-analysis of genome-wide data. Surprisingly, several major models of p53-dependent gene regulation are implausible. Meta-analysis of large-scale data is unable to confirm reports on directly repressed p53 target genes and falsifies models of direct repression. This notion is supported by experimental re-analysis of representative genes reported as directly repressed by p53. Therefore, p53 is not a direct repressor of transcription, but solely activates its target genes. Moreover, models based on interference of p53 with activating transcription factors as well as models based on the function of ncRNAs are also not supported by the meta-analysis. As an alternative to models of direct repression, the meta-analysis leads to the conclusion that p53 represses transcription indirectly by activation of the p53-p21-DREAM/RB pathway.
Collapse
Key Words
- CDE, cell cycle-dependent element
- CDKN1A
- CHR, cell cycle genes homology region
- ChIP, chromatin immunoprecipitation
- DREAM complex
- DREAM, DP, RB-like, E2F4, and MuvB complex
- E2F/RB complex
- HPV, human papilloma virus
- NF-Y, Nuclear factor Y
- cdk, cyclin-dependent kinase
- genome-wide meta-analysis
- p53
Collapse
Affiliation(s)
- Martin Fischer
- a Molecular Oncology; Medical School ; University of Leipzig ; Leipzig , Germany
| | | | | |
Collapse
|
16
|
Piera-Velazquez S, Jimenez SA. Role of cellular senescence and NOX4-mediated oxidative stress in systemic sclerosis pathogenesis. Curr Rheumatol Rep 2015; 17:473. [PMID: 25475596 DOI: 10.1007/s11926-014-0473-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and numerous internal organs and a severe fibroproliferative vasculopathy resulting frequently in severe disability and high mortality. Although the etiology of SSc is unknown and the detailed mechanisms responsible for the fibrotic process have not been fully elucidated, one important observation from a large US population study was the demonstration of a late onset of SSc with a peak incidence between 45 and 54 years of age in African-American females and between 65 and 74 years of age in white females. Although it is not appropriate to consider SSc as a disease of aging, the possibility that senescence changes in the cellular elements involved in its pathogenesis may play a role has not been thoroughly examined. The process of cellular senescence is extremely complex, and the mechanisms, molecular events, and signaling pathways involved have not been fully elucidated; however, there is strong evidence to support the concept that oxidative stress caused by the excessive generation of reactive oxygen species may be one important mechanism involved. On the other hand, numerous studies have implicated oxidative stress in SSc pathogenesis, thus, suggesting a plausible mechanism in which excessive oxidative stress induces cellular senescence and that the molecular events associated with this complex process play an important role in the fibrotic and fibroproliferative vasculopathy characteristic of SSc. Here, recent studies examining the role of cellular senescence and of oxidative stress in SSc pathogenesis will be reviewed.
Collapse
Affiliation(s)
- Sonsoles Piera-Velazquez
- Scleroderma Center, Thomas Jefferson University, 233 South 10th Street, Suite 509 BLSB, Philadelphia, PA, 19107, USA
| | | |
Collapse
|
17
|
IFI16 Expression Is Related to Selected Transcription Factors during B-Cell Differentiation. J Immunol Res 2015; 2015:747645. [PMID: 26185770 PMCID: PMC4491573 DOI: 10.1155/2015/747645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/27/2015] [Accepted: 05/14/2015] [Indexed: 01/21/2023] Open
Abstract
The interferon-inducible DNA sensor IFI16 is involved in the modulation of cellular survival, proliferation, and differentiation. In the hematopoietic system, IFI16 is consistently expressed in the CD34+ stem cells and in peripheral blood lymphocytes; however, little is known regarding its regulation during maturation of B- and T-cells. We explored the role of IFI16 in normal B-cell subsets by analysing its expression and relationship with the major transcription factors involved in germinal center (GC) development and plasma-cell (PC) maturation. IFI16 mRNA was differentially expressed in B-cell subsets with significant decrease in IFI16 mRNA in GC and PCs with respect to naïve and memory subsets. IFI16 mRNA expression is inversely correlated with a few master regulators of B-cell differentiation such as BCL6, XBP1, POU2AF1, and BLIMP1. In contrast, IFI16 expression positively correlated with STAT3, REL, SPIB, RELA, RELB, IRF4, STAT5B, and STAT5A. ARACNE algorithm indicated a direct regulation of IFI16 by BCL6, STAT5B, and RELB, whereas the relationship between IFI16 and the other factors is modulated by intermediate factors. In addition, analysis of the CD40 signaling pathway showed that IFI16 gene expression directly correlated with NF-κB activation, indicating that IFI16 could be considered an upstream modulator of NF-κB in human B-cells.
Collapse
|
18
|
Chaum E, Winborn CS, Bhattacharya S. Genomic regulation of senescence and innate immunity signaling in the retinal pigment epithelium. Mamm Genome 2015; 26:210-21. [PMID: 25963977 DOI: 10.1007/s00335-015-9568-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/02/2015] [Indexed: 01/04/2023]
Abstract
The tumor suppressor p53 is a major regulator of genes important for cell cycle arrest, senescence, apoptosis, and innate immunity, and has recently been implicated in retinal aging. In this study we sought to identify the genetic networks that regulate p53 function in the retina using quantitative trait locus (QTL) analysis. First we examined age-associated changes in the activation and expression levels of p53; known p53 target proteins and markers of innate immune system activation in primary retinal pigment epithelial (RPE) cells that were harvested from young and aged human donors. We observed increased expression of p53, activated caspase-1, CDKN1A, CDKN2A (p16INK4a), TLR4, and IFNα in aged primary RPE cell lines. We used the Hamilton Eye Institute (HEI) retinal dataset ( www.genenetwork.org ) to identify genomic loci that modulate expression of genes in the p53 pathway in recombinant inbred BXD mouse strains using a QTL systems biology-based approach. We identified a significant trans-QTL on chromosome 1 (region 172-177 Mb) that regulates the expression of Cdkn1a. Many of the genes in this QTL locus are involved in innate immune responses, including Fc receptors, interferon-inducible family genes, and formin 2. Importantly, we found an age-related increase in FCGR3A and FMN2 and a decrease in IFI16 levels in RPE cultures. There is a complex multigenic innate immunity locus that controls expression of genes in the p53 pathway in the RPE, which may play an important role in modulating age-related changes in the retina.
Collapse
Affiliation(s)
- Edward Chaum
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA,
| | | | | |
Collapse
|
19
|
Panchanathan R, Liu H, Choubey D. Activation of p53 in Human and Murine Cells by DNA-Damaging Agents Differentially Regulates Aryl Hydrocarbon Receptor Levels. Int J Toxicol 2015; 34:242-9. [PMID: 25878193 DOI: 10.1177/1091581815578013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates multiple cellular processes. The anticancer drug doxorubicin (DOX) can activate AhR-mediated transcription of target genes. Because DOX in cells activates a DNA damage response involving ataxia telangiectasia-mutated (ATM)-mediated activation of p53, we investigated whether the activation of the p53 in cells by DNA-damaging agents such as DOX or bleomycin could regulate the AhR levels. Here we report that activation of p53 by DNA-damaging agents in human cells increased levels of AhR through a posttranscriptional mechanism. Accordingly, fibroblasts from ATM patients, which are defective in p53 activation, expressed reduced constitutive levels of AhR and treatment of cells with bleomycin did not appreciably increase the AhR levels. Further, activation of p53 in cells stimulated the expression of AhR target genes. In murine cells, activation of p53 reduced the levels of AhR messenger RNA and protein and reduced the expression of AhR target genes. Our observations revealed that activation of p53 in human and murine cells differentially regulates AhR levels.
Collapse
Affiliation(s)
- Ravichandran Panchanathan
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Hongzhu Liu
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Divaker Choubey
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, USA Department of Research Cincinnati VA Medical Center, Cincinnati, OH, USA
| |
Collapse
|
20
|
Diner BA, Li T, Greco TM, Crow MS, Fuesler JA, Wang J, Cristea IM. The functional interactome of PYHIN immune regulators reveals IFIX is a sensor of viral DNA. Mol Syst Biol 2015; 11:787. [PMID: 25665578 PMCID: PMC4358659 DOI: 10.15252/msb.20145808] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The human PYHIN proteins, AIM2, IFI16, IFIX, and MNDA, are critical regulators of immune response, transcription, apoptosis, and cell cycle. However, their protein interactions and underlying mechanisms remain largely uncharacterized. Here, we provide the interaction network for all PYHIN proteins and define a function in sensing of viral DNA for the previously uncharacterized IFIX protein. By designing a cell-based inducible system and integrating microscopy, immunoaffinity capture, quantitative mass spectrometry, and bioinformatics, we identify over 300 PYHIN interactions reflective of diverse functions, including DNA damage response, transcription regulation, intracellular signaling, and antiviral response. In view of the IFIX interaction with antiviral factors, including nuclear PML bodies, we further characterize IFIX and demonstrate its function in restricting herpesvirus replication. We discover that IFIX detects viral DNA in both the nucleus and cytoplasm, binding foreign DNA via its HIN domain in a sequence-non-specific manner. Furthermore, IFIX contributes to the induction of interferon response. Our results highlight the value of integrative proteomics in deducing protein function and establish IFIX as an antiviral DNA sensor important for mounting immune responses.
Collapse
Affiliation(s)
- Benjamin A Diner
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - Tuo Li
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - Todd M Greco
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - Marni S Crow
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - John A Fuesler
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - Jennifer Wang
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ, USA
| |
Collapse
|
21
|
Ferrocifen derivatives that induce senescence in cancer cells: selected examples. J Inorg Biochem 2014; 141:144-151. [DOI: 10.1016/j.jinorgbio.2014.08.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 01/01/2023]
|
22
|
Discovering transcription and splicing networks in myelodysplastic syndromes. PLoS One 2013; 8:e79118. [PMID: 24244432 PMCID: PMC3828332 DOI: 10.1371/journal.pone.0079118] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/17/2013] [Indexed: 11/19/2022] Open
Abstract
More and more transcription factors and their motifs have been reported and linked to specific gene expression levels. However, focusing only on transcription is not sufficient for mechanism research. Most genes, especially in eukaryotes, are alternatively spliced to different isoforms. Some of these isoforms increase the biodiversity of proteins. From this viewpoint, transcription and splicing are two of important mechanisms to modulate expression levels of isoforms. To integrate these two kinds of regulation, we built a linear regression model to select a subset of transcription factors and splicing factors for each co-expressed isoforms using least-angle regression approach. Then, we applied this method to investigate the mechanism of myelodysplastic syndromes (MDS), a precursor lesion of acute myeloid leukemia. Results suggested that expression levels of most isoforms were regulated by a set of selected regulatory factors. Some of the detected factors, such as EGR1 and STAT family, are highly correlated with progression of MDS. We discovered that the splicing factor SRSF11 experienced alternative splicing switch, and in turn induced different amino acid sequences between MDS and controls. This splicing switch causes two different splicing mechanisms. Polymerase Chain Reaction experiments also confirmed that one of its isoforms was over-expressed in MDS. We analyzed the regulatory networks constructed from the co-expressed isoforms and their regulatory factors in MDS. Many of these networks were enriched in the herpes simplex infection pathway which involves many splicing factors, and pathways in cancers and acute or chronic myeloid leukemia.
Collapse
|
23
|
Panchanathan R, Liu H, Xin D, Choubey D. Identification of a negative feedback loop between cyclic di-GMP-induced levels of IFI16 and p202 cytosolic DNA sensors and STING. Innate Immun 2013; 20:751-9. [PMID: 24131791 DOI: 10.1177/1753425913507097] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A host type I IFN response is induced by cytosolic sensing of the bacterial second messenger cyclic-di-GMP (c-di-GMP) by STING (stimulator of IFN genes). Because the STING, an adaptor protein, links the cytosolic detection of DNA by the cytosolic DNA sensors such as the IFN-inducible human IFI16 and murine p202 proteins to the TBK1/IRF3 axis, we investigated whether c-di-GMP-induced signaling could regulate expression of IFI16 and p202 proteins. Here, we report that activation of c-di-GMP-induced signaling in human and murine cells increased steady-state levels of IFI16 and p202 proteins. The increase was c-di-GMP concentration- and time-dependent. Unexpectedly, treatment of cells with type I IFN decreased levels of the adaptor protein STING. Therefore, we investigated whether the IFI16 or p202 protein could regulate the expression of STING and activation of the TBK1/IRF3 axis. We found that constitutive knockdown of IFI16 or p202 expression in cells increased steady-state levels of STING. Additionally, the knockdown of IFI16 resulted in activation of the TBK1/IRF3 axis. Accordingly, increased levels of the IFI16 or p202 protein in cells decreased STING levels. Together, our observations identify a novel negative feedback loop between c-di-GMP-induced levels of IFI16 and p202 cytosolic DNA sensors and the adaptor protein STING.
Collapse
Affiliation(s)
- Ravichandran Panchanathan
- Department of Environmental Health, University of Cincinnati, OH, USA Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Hongzhu Liu
- Department of Environmental Health, University of Cincinnati, OH, USA Cincinnati VA Medical Center, Cincinnati, OH, USA
| | - Duan Xin
- Department of Environmental Health, University of Cincinnati, OH, USA
| | - Divaker Choubey
- Department of Environmental Health, University of Cincinnati, OH, USA Cincinnati VA Medical Center, Cincinnati, OH, USA
| |
Collapse
|
24
|
Trovato L, Prodam F, Genoni G, De Rienzo F, Walker GE, Moia S, Riccomagno S, Bellone S, Bona G. Involvement of genes related to inflammation and cell cycle in idiopathic short stature. Pituitary 2013; 16:83-90. [PMID: 22382915 DOI: 10.1007/s11102-012-0378-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Idiopathic Short Stature (ISS) defines a condition in which height is <-2SD compared to the mean of a reference population where systemic, endocrinological, nutritional or chromosomal disorders have not been identified and diagnosis is based on exclusion of any known causes of short stature. JAK/STAT pathway is triggered by GH binding to the GH receptor and promotes cellular growth through transcription of GH-responsive genes. In order to identify "candidate genes" differently expressed in ISS subjects with respect to control ones, we analyzed the expression of 84 genes related to JAK/STAT pathway by RT(2) Profiler PCR array approach in a total of 10 subjects. Then, we validated the observed data by Real Time PCR and ELISA assays in a major number of subjects. We found two genes that were differently expressed in ISS subjects with respect to the control group: CXCL9 and FCGR1A/CD64, both significantly up-regulated (fold change 2.17 and 1.70, respectively) and belonging to family of IFN-γ-inducible factors. Further, ISS subjects showed an increased gene expression of IFN-γ and IFI16, higher serum levels of IFN-γ but similar levels of CXCL9 when compared to healthy subjects. In addition, we showed a pubertal modulation of CXCL9 levels. These data suggest that inflammatory and regulatory factors of the cell cycle may be involved in the ISS condition, introducing a new perspective to its etiology.
Collapse
Affiliation(s)
- Letizia Trovato
- Division of Pediatrics, Department of Medical Sciences, University of Piemonte Orientale, 28100, Novara, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Milot E, Fotouhi-Ardakani N, Filep JG. Myeloid nuclear differentiation antigen, neutrophil apoptosis and sepsis. Front Immunol 2012; 3:397. [PMID: 23293639 PMCID: PMC3530780 DOI: 10.3389/fimmu.2012.00397] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 12/07/2012] [Indexed: 11/23/2022] Open
Abstract
Sepsis and septic shock are characterized by prolonged inflammation and delayed resolution, which are associated with suppression of neutrophil apoptosis. The role of the intrinsic apoptotic pathway and intracellular factors in regulation of neutrophil apoptosis remain incompletely understood. We previously reported that the nuclear factor MNDA (myeloid nuclear differentiation antigen) is fundamental to execution of the constitutive neutrophil death program. During neutrophil apoptosis MNDA is cleaved by caspases and relocated to the cytoplasm. However, when challenged with known mediators of sepsis, human neutrophils of healthy donors or neutrophils from patients with sepsis exhibited impaired MNDA relocation/cleavage parallel with myeloid cell leukemia-1 (MCL-1) accumulation and suppression of apoptosis. MNDA knockdown in a model cell line indicated that upon induction of apoptosis, MNDA promotes proteasomal degradation of MCL-1, thereby aggravating mitochondrial dysfunction. Thus, MNDA is central to a novel nucleus-mitochondrion circuit that promotes progression of apoptosis. Disruption of this circuit contributes to neutrophil longevity, thereby identifying MNDA as a potential therapeutic target in sepsis and other inflammatory pathologies.
Collapse
Affiliation(s)
- Eric Milot
- Department of Medicine, Maisonneuve-Rosemont Hospital Research Center, University of Montréal Montréal, QC, Canada
| | | | | |
Collapse
|
26
|
Kondo Y, Nagai K, Nakahata S, Saito Y, Ichikawa T, Suekane A, Taki T, Iwakawa R, Enari M, Taniwaki M, Yokota J, Sakoda S, Morishita K. Overexpression of the DNA sensor proteins, absent in melanoma 2 and interferon-inducible 16, contributes to tumorigenesis of oral squamous cell carcinoma with p53 inactivation. Cancer Sci 2012; 103:782-90. [PMID: 22320325 DOI: 10.1111/j.1349-7006.2012.02211.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 12/27/2011] [Accepted: 12/29/2011] [Indexed: 11/30/2022] Open
Abstract
The development of oral squamous cell carcinoma (OSCC) is a multistep process that requires the accumulation of genetic alterations. To identify genes responsible for OSCC development, we performed high-density single nucleotide polymorphism array analysis and genome-wide gene expression profiling on OSCC tumors. These analyses indicated that the absent in melanoma 2 (AIM2) gene and the interferon-inducible gene 16 (IFI16) mapped to the hematopoietic interferon-inducible nuclear proteins. The 200-amino-acid repeat gene cluster in the amplified region of chromosome 1q23 is overexpressed in OSCC. Both AIM2 and IFI16 are cytoplasmic double-stranded DNA sensors for innate immunity and act as tumor suppressors in several human cancers. Knockdown of AIM2 or IFI16 in OSCC cells results in the suppression of cell growth and apoptosis, accompanied by the downregulation of nuclear factor kappa-light-chain-enhancer of activated B cells activation. Because all OSCC cell lines have reduced p53 activity, wild-type p53 was introduced in p53-deficient OSCC cells. The expression of wild-type p53 suppressed cell growth and induced apoptosis via suppression of nuclear factor kappa-light-chain-enhancer of activated B cells activity. Finally, the co-expression of AIM2 and IFI16 significantly enhanced cell growth in p53-deficient cells; in contrast, the expression of AIM2 and/or IFI16 in cells bearing wild-type p53 suppressed cell growth. Moreover, AIM2 and IFI16 synergistically enhanced nuclear factor kappa-light-chain-enhancer of activated B cells signaling in p53-deficient cells. Thus, expression of AIM2 and IFI16 may have oncogenic activities in the OSCC cells that have inactivated the p53 system.
Collapse
Affiliation(s)
- Yuudai Kondo
- Division of Oral and Maxillofacial Surgery, Medicine of Sensory and Motor Organs, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Choubey D. DNA-responsive inflammasomes and their regulators in autoimmunity. Clin Immunol 2011; 142:223-31. [PMID: 22245264 DOI: 10.1016/j.clim.2011.12.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 12/08/2011] [Accepted: 12/10/2011] [Indexed: 01/31/2023]
Abstract
Upon sensing microbial and self-derived DNA, DNA sensors initiate innate immune responses. These sensors include the interferon (IFN)-inducible Toll-like receptor 9 (TLR9) and PYHIN proteins. Upon sensing DNA, cytosolic (murine Aim2 and human AIM2) and nuclear (IFI16) PYHIN proteins recruit an adaptor protein (ASC) and pro-caspase-1 to form an inflammasome, which activates caspase-1. The activated caspase-1 cleaves pro-IL-1β and pro-IL-18 to generate active forms. However, upon sensing cytosolic DNA, the IFI16 protein recruits STING to induce the expression of type I IFN. Recognition of self DNA by innate immune cells contributes to the production of increased levels of type I IFN. Given that the type I IFNs modulate the expression of inflammasome proteins and that the IFN-inducible proteins inhibit the activity of DNA-responsive inflammasomes, an improved understanding of the molecular mechanisms that regulate the activity of DNA-responsive inflammasomes is likely to identify new therapeutic targets to treat autoimmune diseases.
Collapse
Affiliation(s)
- Divaker Choubey
- Department of Environmental Health, University of Cincinnati, 3223 Eden Avenue, P. O. Box 670056, Cincinnati, OH 45267, USA.
| |
Collapse
|
28
|
IFI16 induction by glucose restriction in human fibroblasts contributes to autophagy through activation of the ATM/AMPK/p53 pathway. PLoS One 2011; 6:e19532. [PMID: 21573174 PMCID: PMC3088686 DOI: 10.1371/journal.pone.0019532] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Accepted: 04/06/2011] [Indexed: 11/28/2022] Open
Abstract
Background Glucose restriction in cells increases the AMP/ATP ratio (energetic stress), which activates the AMPK/p53 pathway. Depending upon the energetic stress levels, cells undergo either autophagy or cell death. Given that the activated p53 induces the expression of IFI16 protein, we investigated the potential role of the IFI16 protein in glucose restriction-induced responses. Methodology/Principal Findings We found that glucose restriction or treatment of human diploid fibroblasts (HDFs) with the activators of the AMPK/p53 pathway induced the expression of IFI16 protein. The induced levels of IFI16 protein were associated with the induction of autophagy and reduced cell survival. Moreover, the increase in the IFI16 protein levels was dependent upon the expression of the functional ATM protein kinase. Importantly, the knockdown of the IFI16 expression in HDFs inhibited the activation of the ATM/AMPK/p53 pathway in response to glucose restriction and also increased the survival of HDFs. Conclusions/Significance Our observations demonstrate a role for the IFI16 protein in the energetic stress-induced regulation of autophagy and cell survival. Additionally, our findings also indicate that the loss of IFI16 expression, as found in certain cancers, may provide a survival advantage to cancer cells in microenvironments with low glucose levels.
Collapse
|
29
|
Duan X, Ponomareva L, Veeranki S, Panchanathan R, Dickerson E, Choubey D. Differential roles for the interferon-inducible IFI16 and AIM2 innate immune sensors for cytosolic DNA in cellular senescence of human fibroblasts. Mol Cancer Res 2011; 9:589-602. [PMID: 21471287 DOI: 10.1158/1541-7786.mcr-10-0565] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The IFN-inducible IFI16 and AIM2 proteins act as innate immune sensors for cytosolic double-stranded DNA (dsDNA). On sensing dsDNA, the IFI16 protein induces the expression of IFN-β whereas the AIM2 protein forms an inflammasome, which promotes the secretion of IL-1β. Given that the knockdown of IFI16 expression in human diploid fibroblasts (HDF) delays the onset of cellular senescence, we investigated the potential roles for the IFI16 and AIM2 proteins in cellular senescence. We found that increased IFI16 protein levels in old (vs. young) HDFs were associated with the induction of IFN-β. In contrast, increased levels of the AIM2 protein in the senescent (vs. old) HDFs were associated with increased production of IL-1β. The knockdown of type I IFN-α receptor subunit, which reduced the basal levels of the IFI16 but not of the AIM2, protein delayed the onset of cellular senescence. Accordingly, increased constitutive levels of IFI16 and AIM2 proteins in ataxia telangiectasia mutated (ATM) HDFs were associated with the activation of the IFN signaling and increased levels of IL-1β. The IFN-β treatment of the young HDFs, which induced the expression of IFI16 and AIM2 proteins, activated a DNA damage response and also increased basal levels of IL-1β. Interestingly, the knockdown of AIM2 expression in HDFs increased the basal levels of IFI16 protein and activated the IFN signaling. In contrast, the knockdown of the IFI16 expression in HDFs decreased the basal and dsDNA-induced activation of the IFN signaling. Collectively, our observations show differential roles for the IFI16 and AIM2 proteins in cellular senescence and associated secretory phenotype.
Collapse
Affiliation(s)
- Xin Duan
- Department of Environmental Health, University of Cincinnati, 3223 Eden Avenue, Cincinnati, OH 45267, USA
| | | | | | | | | | | |
Collapse
|
30
|
Veeranki S, Choubey D. Systemic lupus erythematosus and increased risk to develop B cell malignancies: role of the p200-family proteins. Immunol Lett 2010; 133:1-5. [PMID: 20599558 DOI: 10.1016/j.imlet.2010.06.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 06/20/2010] [Indexed: 11/29/2022]
Abstract
Systemic lupus erythematosus (SLE), an autoimmune disease, develops at a female-to-male ratio of 10:1. Increased serum levels of type I interferons (IFN-alpha/beta) and induction of "IFN-signature" genes are associated with an active SLE disease in patients. Moreover, SLE patients exhibit three- to four-fold increase in the risk of developing malignancies involving B cells, including non-Hodgkin lymphoma (NHL) and Hodgkin's lymphoma (HL). Interestingly, homozygous mice expressing a deletion mutant (the proline-rich domain deleted) of the p53 develop various types of spontaneous tumors, particularly of B cell origin upon aging. The deletion is associated with defects in transcriptional activation of genes by p53 and inhibition of DNA damage-induced apoptosis. Notably, increased levels of the p202 protein, which is encoded by the p53-repressible interferon-inducible Ifi202 gene, in B cells of female mice are associated with defects in B cell apoptosis, inhibition of the p53-mediated transcription of pro-apoptotic genes, and increased lupus susceptibility. In this review we discuss how increased levels of the p202 protein (and its human functional homologue IFI16 protein) in B cells increase lupus susceptibility and are likely to increase the risk of developing certain B cell malignancies. A complete understanding of the molecular mechanisms that regulate B cell homeostasis is necessary to identify SLE patients with an increased risk to develop B cell malignancies.
Collapse
Affiliation(s)
- Sudhakar Veeranki
- Department of Environmental Health, University of Cincinnati, 3223 Eden Avenue, PO Box 670056, Cincinnati, OH 45267, United States
| | | |
Collapse
|
31
|
Fotouhi-Ardakani N, Kebir DE, Pierre-Charles N, Wang L, Ahern SP, Filep JG, Milot E. Role for myeloid nuclear differentiation antigen in the regulation of neutrophil apoptosis during sepsis. Am J Respir Crit Care Med 2010; 182:341-50. [PMID: 20395555 DOI: 10.1164/rccm.201001-0075oc] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Suppressed neutrophil apoptosis, a hallmark of sepsis, perpetuates inflammation and delays resolution. Myeloid nuclear differentiation antigen (MNDA) is expressed only in myeloid cells and has been implicated in cell differentiation; however, its function in mature neutrophils is not known. OBJECTIVES We studied whether MNDA could contribute to regulation of apoptosis of neutrophils from healthy subjects and patients with sepsis, and investigated the impact of MNDA knockdown on apoptosis. METHODS Human neutrophils were challenged with mediators of sepsis and neutrophils from patients with sepsis were cultured to investigate cleavage and cytoplasmic accumulation of MNDA. MNDA was knocked down in myeloid HL-60 cells to investigate development of apoptosis. MEASUREMENTS AND MAIN RESULTS During constitutive apoptosis of human neutrophils, MNDA is cleaved by caspases and accumulated in the cytoplasm, where it promotes degradation of the antiapoptotic protein Mcl-1, thereby accelerating collapse of mitochondrial transmembrane potential. Culture of neutrophils with LPS, bacterial DNA, or platelet-activating factor prevented MNDA cleavage and cytoplasmic accumulation. MNDA knockdown with short hairpin RNA markedly attenuated Mcl-1 turnover and conferred resistance to stress-induced apoptosis in HL-60 cells. Neutrophils from patients with severe sepsis exhibited markedly suppressed apoptosis that was associated with impaired cytoplasmic MNDA accumulation, preservation of Mcl-1 expression, and mitochondrial transmembrane potential. Culture of neutrophils of healthy subjects with septic plasma delayed apoptosis and cytoplasmic MNDA accumulation. CONCLUSIONS These results indicate that cytoplasmic accumulation of MNDA facilitates progression of apoptosis and suggest that impaired cytoplasmic MNDA accumulation contributes to delayed neutrophil apoptosis in patients with severe sepsis.
Collapse
|
32
|
Sozzani S, Bosisio D, Scarsi M, Tincani A. Type I interferons in systemic autoimmunity. Autoimmunity 2010; 43:196-203. [DOI: 10.3109/08916930903510872] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
33
|
Interferon-inducible IFI16, a negative regulator of cell growth, down-regulates expression of human telomerase reverse transcriptase (hTERT) gene. PLoS One 2010; 5:e8569. [PMID: 20052289 PMCID: PMC2797294 DOI: 10.1371/journal.pone.0008569] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 12/11/2009] [Indexed: 01/07/2023] Open
Abstract
Background Increased levels of interferon (IFN)-inducible IFI16 protein (encoded by the IFI16 gene located at 1q22) in human normal prostate epithelial cells and diploid fibroblasts (HDFs) are associated with the onset of cellular senescence. However, the molecular mechanisms by which the IFI16 protein contributes to cellular senescence-associated cell growth arrest remain to be elucidated. Here, we report that increased levels of IFI16 protein in normal HDFs and in HeLa cells negatively regulate the expression of human telomerase reverse transcriptase (hTERT) gene. Methodology/Principal Findings We optimized conditions for real-time PCR, immunoblotting, and telomere repeat amplification protocol (TRAP) assays to detect relatively low levels of hTERT mRNA, protein, and telomerase activity that are found in HDFs. Using the optimized conditions, we report that treatment of HDFs with inhibitors of cell cycle progression, such as aphidicolin or CGK1026, which resulted in reduced steady-state levels of IFI16 mRNA and protein, was associated with increases in hTERT mRNA and protein levels and telomerase activity. In contrast, knockdown of IFI16 expression in cells increased the expression of c-Myc, a positive regulator of hTERT expression. Additionally, over-expression of IFI16 protein in cells inhibited the c-Myc-mediated stimulation of the activity of hTERT-luc-reporter and reduced the steady-state levels of c-Myc and hTERT. Conclusions/Significance These data demonstrated that increased levels of IFI16 protein in HDFs down-regulate the expression of hTERT gene. Our observations will serve basis to understand how increased cellular levels of the IFI16 protein may contribute to certain aging-dependent diseases.
Collapse
|
34
|
Integrated biochemical and computational approach identifies BCL6 direct target genes controlling multiple pathways in normal germinal center B cells. Blood 2009; 115:975-84. [PMID: 19965633 DOI: 10.1182/blood-2009-06-227017] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BCL6 is a transcriptional repressor required for mature B-cell germinal center (GC) formation and implicated in lymphomagenesis. BCL6's physiologic function is only partially known because the complete set of its targets in GC B cells has not been identified. To address this issue, we used an integrated biochemical-computational-functional approach to identify BCL6 direct targets in normal GC B cells. This approach includes (1) identification of BCL6-bound promoters by genome-wide chromatin immunoprecipitation, (2) inference of transcriptional relationships by the use of a regulatory network reverse engineering approach (ARACNe), and (3) validation of physiologic relevance of the candidate targets down-regulated in GC B cells. Our approach demonstrated that a large set of promoters (> 4000) is physically bound by BCL6 but that only a fraction of them is repressed in GC B cells. This set of 1207 targets identifies several cellular functions directly controlled by BCL6 during GC development, including activation, survival, DNA-damage response, cell cycle arrest, cytokine signaling, Toll-like receptor signaling, and differentiation. These results define a broad role of BCL6 in preventing centroblasts from responding to signals leading to exit from the GC before they complete the phase of proliferative expansion and of antibody affinity maturation.
Collapse
|
35
|
Li G, Luna C, Qiu J, Epstein DL, Gonzalez P. Alterations in microRNA expression in stress-induced cellular senescence. Mech Ageing Dev 2009; 130:731-41. [PMID: 19782699 PMCID: PMC2795064 DOI: 10.1016/j.mad.2009.09.002] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 08/14/2009] [Accepted: 09/16/2009] [Indexed: 02/08/2023]
Abstract
We investigated miRNA expression changes associated with stress-induced premature senescence (SIPS) in primary cultures of human diploid fibroblast (HDF) and human trabecular meshwork (HTM) cells. Twenty-five miRNAs were identified by miRNA microarray analysis and their changes in expression were validated by TaqMan real-time RT-PCR in three independent cell lines of HTM and HDF. SIPS in both HTM and HDF cell types was associated with significant down-regulation of four members of the miR-15 family and five miRNAs of the miR-106b family located in the oncogenic clusters miR-17-92, miR-106a-363, and miR-106b-25. SIPS was also associated with up-regulation of two miRNAs (182 and 183) from the miR-183-96-182 cluster. Transfection with miR-106a agomir inhibited the up-regulation of p21(CDKN1A) associated with SIPS while transfection with miR-106a antagomir led to increased p21(CDKN1A) expression in senescent cells. In addition, we identified retinoic acid receptor gamma (RARG) as a target of miR-182 and showed that this protein was down-regulated during SIPS in HDF and HTM cells. These results suggest that changes in miRNA expression might contribute to phenotypic alterations of senescent cells by modulating the expression of key regulatory proteins such as p21(CDKN1A) as well as by targeting genes that are down-regulated in senescent cells such as RARG.
Collapse
Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
| | - Coralia Luna
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
| | - Jianming Qiu
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
| | - David L. Epstein
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
| | - Pedro Gonzalez
- Department of Ophthalmology, Duke University, Durham, North Carolina 27710, USA
| |
Collapse
|