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Marrella V, Facoetti A, Cassani B. Cellular Senescence in Immunity against Infections. Int J Mol Sci 2022; 23:ijms231911845. [PMID: 36233146 PMCID: PMC9570409 DOI: 10.3390/ijms231911845] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/16/2022] Open
Abstract
Cellular senescence is characterized by irreversible cell cycle arrest in response to different triggers and an inflammatory secretome. Although originally described in fibroblasts and cell types of solid organs, cellular senescence affects most tissues with advancing age, including the lymphoid tissue, causing chronic inflammation and dysregulation of both innate and adaptive immune functions. Besides its normal occurrence, persistent microbial challenge or pathogenic microorganisms might also accelerate the activation of cellular aging, inducing the premature senescence of immune cells. Therapeutic strategies counteracting the detrimental effects of cellular senescence are being developed. Their application to target immune cells might have the potential to improve immune dysfunctions during aging and reduce the age-dependent susceptibility to infections. In this review, we discuss how immune senescence influences the host’s ability to resolve more common infections in the elderly and detail the different markers proposed to identify such senescent cells; the mechanisms by which infectious agents increase the extent of immune senescence are also reviewed. Finally, available senescence therapeutics are discussed in the context of their effects on immunity and against infections.
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Affiliation(s)
- Veronica Marrella
- UOS Milan Unit, Istituto di Ricerca Genetica e Biomedica (IRGB), CNR, 20138 Milan, Italy
- IRCCS Humanitas Research Hospital, 20089 Milan, Italy
| | - Amanda Facoetti
- Department of Biomedical Sciences, Humanitas University, 20090 Milan, Italy
| | - Barbara Cassani
- IRCCS Humanitas Research Hospital, 20089 Milan, Italy
- Department of Medical Biotechnologies and Translational Medicine, Università Degli Studi di Milano, 20089 Milan, Italy
- Correspondence:
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Fernandes SG, Dsouza R, Khattar E. External environmental agents influence telomere length and telomerase activity by modulating internal cellular processes: Implications in human aging. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 85:103633. [PMID: 33711516 DOI: 10.1016/j.etap.2021.103633] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/30/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
External environment affects cellular physiological processes and impact the stability of our genome. The most important structural components of our linear chromosomes which endure the impact by these agents, are the chromosomal ends called telomeres. Telomeres preserve the integrity of our genome by preventing end to end fusions and telomeric loss through by inhibiting DNA damage response (DDR) activation. This is accomplished by the presence of a six membered shelterin complex at telomeres. Further, telomeres cannot be replicated by normal DNA polymerase and require a special enzyme called telomerase which is expressed only in stem cells, few immune cells and germ cells. Telomeres are rich in guanine content and thus become extremely prone to damage arising due to physiological processes like oxidative stress and inflammation. External environmental factors which includes various physical, biological and chemical agents also affect telomere homeostasis by increasing oxidative stress and inflammation. In the present review, we highlight the effect of these external factors on telomerase activity and telomere length. We also discuss how the external agents affect the physiological processes, thus modulating telomere stability. Further, we describe its implication in the development of aging and its related pathologies.
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Affiliation(s)
- Stina George Fernandes
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be University), Vile Parle West, Mumbai, 400056, India
| | - Rebecca Dsouza
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be University), Vile Parle West, Mumbai, 400056, India
| | - Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be University), Vile Parle West, Mumbai, 400056, India.
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Humphreys D, ElGhazaly M, Frisan T. Senescence and Host-Pathogen Interactions. Cells 2020; 9:cells9071747. [PMID: 32708331 PMCID: PMC7409240 DOI: 10.3390/cells9071747] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 12/14/2022] Open
Abstract
Damage to our genomes triggers cellular senescence characterised by stable cell cycle arrest and a pro-inflammatory secretome that prevents the unrestricted growth of cells with pathological potential. In this way, senescence can be considered a powerful innate defence against cancer and viral infection. However, damage accumulated during ageing increases the number of senescent cells and this contributes to the chronic inflammation and deregulation of the immune function, which increases susceptibility to infectious disease in ageing organisms. Bacterial and viral pathogens are masters of exploiting weak points to establish infection and cause devastating diseases. This review considers the emerging importance of senescence in the host-pathogen interaction: we discuss the pathogen exploitation of ageing cells and senescence as a novel hijack target of bacterial pathogens that deploys senescence-inducing toxins to promote infection. The persistent induction of senescence by pathogens, mediated directly through virulence determinants or indirectly through inflammation and chronic infection, also contributes to age-related pathologies such as cancer. This review highlights the dichotomous role of senescence in infection: an innate defence that is exploited by pathogens to cause disease.
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Affiliation(s)
- Daniel Humphreys
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK;
- Correspondence: (D.H.); (T.F.)
| | - Mohamed ElGhazaly
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK;
| | - Teresa Frisan
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Correspondence: (D.H.); (T.F.)
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Sun Y, Wang W, Jiao YR, Ren J, Gao L, Li Y, Hu P, Ren TY, Han QF, Chen C, Yao HC. Leukocyte telomere length: a potential biomarker for the prognosis of coronary artery disease. Biomark Med 2020; 14:933-941. [PMID: 32613841 DOI: 10.2217/bmm-2020-0171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/10/2020] [Indexed: 11/21/2022] Open
Abstract
Aim: This study aimed to explore the prognostic value of leukocyte telomere length (LTL) in patients with coronary artery disease (CAD). Materials & methods: We enrolled 366 CAD patients and 76 healthy subjects in this study. LTL was measured. All subjects were followed up for 6 months for further analysis regarding major adverse cardiac events (MACEs). Results: CAD patients had a significantly shortened LTL compared with healthy subjects (p < 0.05). The area under the curve for LTL prediction of MACEs was 0.769 (p < 0.001), with a shorter LTL being an independent predictor of MACEs (Cox proportional hazards regression, hazard ratio: 2.866; p < 0.001). Conclusion: LTL could be considered as an independent predictor of short-term MACEs in CAD.
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Affiliation(s)
- Ying Sun
- Department of Cardiology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
| | - Wei Wang
- Department of Cardiology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
| | - Yue-Ru Jiao
- Department of Cardiology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
| | - Jian Ren
- Department of Cardiology, Liaocheng Dongchangfu People's Hospital, The second affiliated Hospital of Liaocheng University, Liaocheng, 252000, China
| | - Lei Gao
- Zhong Yuan Academy of Biological Medicine, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong Province, 252000, China
| | - Yang Li
- Zhong Yuan Academy of Biological Medicine, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong Province, 252000, China
| | - Ping Hu
- Zhong Yuan Academy of Biological Medicine, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong Province, 252000, China
| | - Tian-Ying Ren
- Zhong Yuan Academy of Biological Medicine, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong Province, 252000, China
| | - Qian-Feng Han
- Department of Cardiology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
| | - Chen Chen
- Department of Urology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
| | - Heng-Chen Yao
- Department of Cardiology, Liaocheng People's Hospital, Cheeloo college of Medicine, Shandong University & Clinical School of Shandong First Medical University, Liaocheng, Shandong Province, 252000, China
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Tanaka M, Tanaka K, Ida C, Oue A, Yamashita S, Yao J, Takenouchi N, Miwa M. Conflicting effects of poly(ADP-ribose) polymerase inhibitor on cell-mediated and virion-mediated HTLV-1 infection. Virus Res 2019; 270:197653. [PMID: 31299194 DOI: 10.1016/j.virusres.2019.197653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 04/16/2019] [Accepted: 07/08/2019] [Indexed: 11/18/2022]
Abstract
Adult T-cell leukemia and human T-cell leukemia virus type 1 (HTLV-1) - associated myelopathy/tropical spastic paraparesis, which develop after HTLV-1 infection, are difficult to cure. In particular, the mode of HTLV-1 propagation is not well understood. Poly (ADP-ribose) polymerase-1 is reported to be a co-activator of HTLV-1 Tax protein; however, the effects of polyADP-ribosylation on infectivity of HTLV-1 have not been fully clarified. We studied the effects of a PARP inhibitor on two modes of HTLV-1 transmission: through cell adhesion between MT-2 cells (an HTLV-1-infected cell line) and uninfected cells and through virus particles produced by HTLV-1-producing c77 cells. Although the PARP inhibitor decreased HTLV-1 infection through cell adhesion, it increased HTLV-1 infection through virion production and caused apoptosis of HTLV-1-infected cells. Thus, careful consideration is required for clinical application of PARP inhibitors in HTLV-1 patients.
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Affiliation(s)
- Masakazu Tanaka
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan; Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima, Kagoshima 890-8544, Japan.
| | - Koji Tanaka
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan; Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Chieri Ida
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan; College of Nagoya Women's University, Nagoya, Aichi, 467-8610, Japan
| | - Atsushi Oue
- Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Sachiko Yamashita
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Jinchun Yao
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Norihiro Takenouchi
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Masanao Miwa
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan; Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan
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Bellon M, Nicot C. Telomere Dynamics in Immune Senescence and Exhaustion Triggered by Chronic Viral Infection. Viruses 2017; 9:v9100289. [PMID: 28981470 PMCID: PMC5691640 DOI: 10.3390/v9100289] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 02/06/2023] Open
Abstract
The progressive loss of immunological memory during aging correlates with a reduced proliferative capacity and shortened telomeres of T cells. Growing evidence suggests that this phenotype is recapitulated during chronic viral infection. The antigenic volume imposed by persistent and latent viruses exposes the immune system to unique challenges that lead to host T-cell exhaustion, characterized by impaired T-cell functions. These dysfunctional memory T cells lack telomerase, the protein capable of extending and stabilizing chromosome ends, imposing constraints on telomere dynamics. A deleterious consequence of this excessive telomere shortening is the premature induction of replicative senescence of viral-specific CD8+ memory T cells. While senescent cells are unable to expand, they can survive for extended periods of time and are more resistant to apoptotic signals. This review takes a closer look at T-cell exhaustion in chronic viruses known to cause human disease: Epstein–Barr virus (EBV), Hepatitis B/C/D virus (HBV/HCV/HDV), human herpesvirus 8 (HHV-8), human immunodeficiency virus (HIV), human T-cell leukemia virus type I (HTLV-I), human papillomavirus (HPV), herpes simplex virus-1/2 (HSV-1/2), and Varicella–Zoster virus (VZV). Current literature linking T-cell exhaustion with critical telomere lengths and immune senescence are discussed. The concept that enduring antigen stimulation leads to T-cell exhaustion that favors telomere attrition and a cell fate marked by enhanced T-cell senescence appears to be a common endpoint to chronic viral infections.
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Affiliation(s)
- Marcia Bellon
- Department of Pathology, Center for Viral Pathogenesis, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Christophe Nicot
- Department of Pathology, Center for Viral Pathogenesis, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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Chaib-Mezrag H, Lemaçon D, Fontaine H, Bellon M, Bai XT, Drac M, Coquelle A, Nicot C. Tax impairs DNA replication forks and increases DNA breaks in specific oncogenic genome regions. Mol Cancer 2014; 13:205. [PMID: 25185513 PMCID: PMC4168069 DOI: 10.1186/1476-4598-13-205] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/26/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Human T-cell leukemia virus type 1 (HTLV-I) is a human retrovirus associated with adult T-cell leukemia (ATL), an aggressive CD4 T-cell proliferative disease with dismal prognosis. The long latency preceding the development of the disease and the low incidence suggests that the virus itself is not sufficient for transformation and that genetic defects are required to create a permissive environment for leukemia. In fact, ATL cells are characterized by profound genetic modifications including structural and numerical chromosome alterations. RESULTS In this study we used molecular combing techniques to study the effect of the oncoprotein Tax on DNA replication. We found that replication forks have difficulties replicating complex DNA, fork progression is slower, and they pause or stall more frequently in the presence of Tax expression. Our results also show that Tax-associated replication defects are partially compensated by an increase in the firing of back-up origins. Consistent with these effects of Tax on DNA replication, an increase in double strand DNA breaks (DDSB) was seen in Tax expressing cells. Tax-mediated increases in DDSBs were associated with the ability of Tax to activate NF-kB and to stimulate intracellular nitric oxide production. We also demonstrated a reduced expression of human translesion synthesis (TLS) DNA polymerases Pol-H and Pol-K in HTLV-I-transformed T cells and ATL cells. This was associated with an increase in DNA breaks induced by Tax at specific genome regions, such as the c-Myc and the Bcl-2 major breakpoints. Consistent with the notion that the non-homologous end joining (NHEJ) pathway is hyperactive in HTLV-I-transformed cells, we found that inhibition of the NHEJ pathway induces significant killing of HTLV-I transformed cells and patient-derived leukemic ATL cells. CONCLUSION Our results suggest that, replication problems increase genetic instability in HTLV-I-transformed cells. As a result, abuse of NHEJ and a defective homologous repair (HR) DNA repair pathway can be targeted as a new therapeutic approach for the treatment of adult T-cell leukemia.
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Affiliation(s)
- Hassiba Chaib-Mezrag
- />Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 USA
| | - Delphine Lemaçon
- />IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298 France
- />INSERM, U896, Montpellier, F-34298 France
- />Université Montpellier 1, Montpellier, F-34298 France
- />Institut régional du Cancer Montpellier, Montpellier, F-34298 France
| | - Hélène Fontaine
- />IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298 France
- />INSERM, U896, Montpellier, F-34298 France
- />Université Montpellier 1, Montpellier, F-34298 France
- />Institut régional du Cancer Montpellier, Montpellier, F-34298 France
| | - Marcia Bellon
- />Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 USA
| | - Xue Tao Bai
- />Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 USA
| | - Marjorie Drac
- />DNA Combing Facility, Institut de Génétique Moléculaire, CNRS UMR5535 & BioCampus Montpellier (UMS3426), 1919 route de Mende, Montpellier cedex 5, 34293 France
| | - Arnaud Coquelle
- />IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298 France
- />INSERM, U896, Montpellier, F-34298 France
- />Université Montpellier 1, Montpellier, F-34298 France
- />Institut régional du Cancer Montpellier, Montpellier, F-34298 France
| | - Christophe Nicot
- />Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 USA
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Fields PA, Taylor GP. "Antivirals" in the treatment of adult T cell leukaemia- lymphoma (ATLL). Curr Hematol Malig Rep 2013; 7:267-75. [PMID: 23093306 DOI: 10.1007/s11899-012-0139-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adult T cell leukaemia / lymphoma (ATLL) is a mature (post thymic) T cell lymphoma caused by the human T-lymphotropic virus type 1 (HTLV-1) infection. Overall survival in the aggressive subtypes (Acute Leukaemia and Lymphomatous) remains poor in part due to chemotherapy resistance. To improve treatment outcome for de novo disease, better induction therapies are required and since the pathogenic agent is known it would seem sensible to target the virus. In a recent meta-analysis the use of zidovudine and interferon alpha (ZDV/IFN) has been associated with improved response rates and prolonged overall survival in leukemic subtypes of ATLL (both acute and Chronic) confirmed in a multivariate analysis. In a more recent UK study the overall response rate for patients with aggressive ATLL treated with chemotherapy alone was 49 % compared to 81 % with combined first line therapy (chemotherapy with concurrent or sequential ZDV/IFN). Combined first line therapy prolonged median OS in acute (p = 0.0081) and lymphomatous ATLL (p = 0.001).These data support the use of low dose ZDV/IFN with chemotherapy as first line treatment for patients with newly diagnosed aggressive ATLL. Although the mechanisms of action are incompletely understood, some possible explanations for their efficacy will be discussed.
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Affiliation(s)
- Paul A Fields
- Department of Haematology, Guys and St Thomas', Kings College Hospitals, London, SE1 9RT, UK.
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HTLV-I tax increases genetic instability by inducing DNA double strand breaks during DNA replication and switching repair to NHEJ. PLoS One 2012; 7:e42226. [PMID: 22916124 PMCID: PMC3423393 DOI: 10.1371/journal.pone.0042226] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 07/02/2012] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Appropriate responses to damaged DNA are indispensible for preserving genome stability and preventing cancer. Tumor viruses often target DNA repair machinery to achieve transformation. The Human T-cell leukemia virus type I (HTLV-I) is the only known transforming human retrovirus and the etiological agent of Adult T-cell Leukemia (ATLL). Although HTLV-I-transformed leukemic cells have numerous genetic lesions, the precise role of the viral tax gene in this process is not fully understood. RESULTS Our results show a novel function of HTLV-I oncoprotein Tax as an inducer of genomic DNA double strand breaks (DDSB) during DNA replication. We also found that Tax acts as a potent inhibitor of homologous recombination (HR) DNA repair through the activation of the NF-kB pathway. These results were confirmed using HTLV-I molecular clones expressing Tax at physiological levels in a natural context. We further found that HTLV-I- and Tax-transformed cells are not more susceptible to DNA damaging agents and repair DNA lesions at a rate similar to that of normal cells. Finally, we demonstrated that during S phase, Tax-associated DDSB are preferentially repaired using the error-prone non-homologous end joining (NHEJ) pathway. CONCLUSIONS This study provides new insights in Tax effects on DNA repair and genome instability. Although it may not be self sufficient, the creation of DNA breaks and subsequent abnormal use of the non-conservative NHEJ DNA repair during the S phase in HTLV-I-infected Tax-expressing cells may cooperate with other factors to increase genetic and genome instability and favor transformation.
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Bidoia C. Human T-lymphotropic virus proteins and post-translational modification pathways. World J Virol 2012; 1:115-30. [PMID: 24175216 PMCID: PMC3782272 DOI: 10.5501/wjv.v1.i4.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 06/04/2012] [Accepted: 07/13/2012] [Indexed: 02/05/2023] Open
Abstract
Cell life from the cell cycle to the signaling transduction and response to stimuli is finely tuned by protein post-translational modifications (PTMs). PTMs alter the conformation, the stability, the localization, and hence the pattern of interactions of the targeted protein. Cell pathways involve the activation of enzymes, like kinases, ligases and transferases, that, once activated, act on many proteins simultaneously, altering the state of the cell and triggering the processes they are involved in. Viruses enter a balanced system and hijack the cell, exploiting the potential of PTMs either to activate viral encoded proteins or to alter cellular pathways, with the ultimate consequence to perpetuate through their replication. Human T-lymphotropic virus type 1 (HTLV-1) is known to be highly oncogenic and associates with adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis and other inflammatory pathological conditions. HTLV-1 protein activity is controlled by PTMs and, in turn, viral activity is associated with the modulation of cellular pathways based on PTMs. More knowledge is acquired about the PTMs involved in the activation of its proteins, like Tax, Rex, p12, p13, p30, HTLV-I basic leucine zipper factor and Gag. However, more has to be understood at the biochemical level in order to counteract the associated fatal outcomes. This review will focus on known PTMs that directly modify HTLV-1 components and on enzymes whose activity is modulated by viral proteins.
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Affiliation(s)
- Carlo Bidoia
- Carlo Bidoia, Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland
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11
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Human T-lymphotropic type 1 virus p30 inhibits homologous recombination and favors unfaithful DNA repair. Blood 2011; 117:5897-906. [PMID: 21427292 DOI: 10.1182/blood-2010-08-304600] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Whereas oncogenic retroviruses are common in animals, human T-lymphotropic virus 1 (HTLV-1) is the only transmissible retrovirus associated with cancer in humans and is etiologically linked to adult T-cell leukemia. The leukemogenesis process is still largely unknown, but relies on extended survival and clonal expansion of infected cells, which in turn accumulate genetic defects. A common feature of human tumor viruses is their ability to stimulate proliferation and survival of infected pretumoral cells and then hide by establishing latency in cells that have acquired a transformed phenotype. Whereas disruption of the DNA repair is one of the major processes responsible for the accumulation of genomic abnormalities and carcinogenesis, the absence of DNA repair also poses the threat of cell-cycle arrest or apoptosis of virus-infected cells. This study describes how the HTLV-1 p30 viral protein inhibits conservative homologous recombination (HR) DNA repair by targeting the MRE11/RAD50/NBS1 complex and favors the error-prone nonhomologous-end-joining (NHEJ) DNA-repair pathway instead. As a result, HTLV-1 p30 may facilitate the accumulation of mutations in the host genome and the cumulative risk of transformation. Our results provide new insights into how human tumor viruses may manipulate cellular DNA-damage responses to promote cancer.
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Tsai TL, Shieh DB, Yeh CS, Tzeng Y, Htet K, Chuang KS, Hwu JR, Su WC. The down regulation of target genes by photo activated DNA nanoscissors. Biomaterials 2010; 31:6545-54. [DOI: 10.1016/j.biomaterials.2010.04.058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Accepted: 04/29/2010] [Indexed: 01/24/2023]
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13
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Santra S, Kaittanis C, Perez JM. Aliphatic hyperbranched polyester: a new building block in the construction of multifunctional nanoparticles and nanocomposites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5364-73. [PMID: 19957939 PMCID: PMC2854188 DOI: 10.1021/la9037843] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Herein we report the design and synthesis of multifunctional hyperbranched polyester-based nanoparticles and nanocomposites with properties ranging from magnetic, fluorescence, antioxidant and X-ray contrast. The fabrication of these nanostructures was achieved using a novel aliphatic and biodegradable hyperbranched polyester (HBPE) synthesized from readily available diethyl malonate. The polymer's globular structure with functional surface carboxylic groups and hydrophobic cavities residing in the polymer's interior allows for the formation of multifunctional polymeric nanoparticles, which are able to encapsulate a diversity of hydrophobic cargos. Via simple surface chemistry modifications, the surface carboxylic acid groups were modified to yield nanoparticles with a variety of surface functionalizations, such as amino, azide and propargyl groups, which mediated the conjugation of small molecules. This capability achieved the engineering of the HBPE nanoparticle surface for specific cell internalization studies and the formation of nanoparticle assemblies for the creation of novel nanocomposites that retained, and in some cases enhanced, the properties of the parental nanoparticle building blocks. Considering these results, the HBPE polymer, nanoparticles and composites should be ideal for biomedical, pharmaceutical, nanophotonics applications.
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Affiliation(s)
- Santimukul Santra
- Nanoscience Technology Center, College of Medicine, University of Central Florida, 12424 Research Parkway, Orlando, Florida 32826, USA
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14
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HTLV-I Tax-dependent and -independent events associated with immortalization of human primary T lymphocytes. Blood 2010; 115:2441-8. [PMID: 20093405 DOI: 10.1182/blood-2009-08-241117] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Human T-cell leukemia virus type I (HTLV-I)-associated malignancies are seen in a small percentage of infected persons. Although in vitro immortalization by HTLV-I virus is very efficient, we report that Tax has poor oncogenic activity in human primary T cells and that immortalization by Tax is rare. Sustained telomerase activity represents one of the oncogenic steps required for Tax-mediated immortalization. Tax expression was required for the growth of primary T cells, but was not sufficient to propel T cells into cell cycle in the absence of exogenous interleukin-2 (IL-2). Tax was sufficient to activate the phosphoinositide-3 kinase (PI3K)/Akt pathway as shown by down regulation of Src homology phosphatase-1 and increased phosphorylation of Akt. We also found disruption of putative tumor suppressors IL-16 and translocated promoter region (TPR) in Tax-immortalized and HTLV-I-transformed cell lines. Our results confirmed previous observations that Tax activates the anaphase-promoting complex. However, Tax did not affect the mitotic spindle checkpoint, which was also functional in HTLV-I-transformed cells. These data provide a better understanding of Tax functions in human T cells, and highlight the limitations of Tax, suggesting that other viral proteins are key to T-cell transformation and development of adult T-cell leukemia.
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Taylor JM, Nicot C. HTLV-1 and apoptosis: role in cellular transformation and recent advances in therapeutic approaches. Apoptosis 2008; 13:733-47. [PMID: 18421579 DOI: 10.1007/s10495-008-0208-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A universal cellular defense mechanism against viral invasion is the elimination of infected cells through apoptotic cell death. To counteract host defenses many viruses have evolved complex apoptosis evasion strategies. The oncogenic human retrovirus HTLV-1 is the etiological agent of adult-T-cell leukemia/lymphoma (ATLL) and the neurodegenerative disease known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The poor prognosis in HTLV-1-induced ATLL is linked to the resistance of neoplastic T cells against conventional therapies and the immuno-compromised state of patients. Nevertheless, several studies have shown that the apoptotic pathway is largely intact and can be reactivated in ATLL tumor cells to induce specific killing. A better understanding of the molecular mechanisms employed by HTLV-1 to counteract cellular death pathways remains an important challenge for future therapies and the treatment of HTLV-1-associated diseases.
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Affiliation(s)
- John M Taylor
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kansas Medical Center, 3025 Wahl Hall West, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
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