1
|
Hassan MS, Morgan AM, Mekawy MM, Zeineb M. Molecular mechanisms of Cisplatin- induced placental toxicity and teratogenicity in rats and the ameliorating role of N-acetyl-cysteine. Int J Biochem Cell Biol 2019; 115:105579. [DOI: 10.1016/j.biocel.2019.105579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 11/23/2022]
|
2
|
Kübler J, Kirschner S, Hartmann L, Welzel G, Engelhardt M, Herskind C, Veldwijk MR, Schultz C, Felix M, Glatting G, Maier P, Wenz F, Brockmann MA, Giordano FA. The HIV-derived protein Vpr52-96 has anti-glioma activity in vitro and in vivo. Oncotarget 2018; 7:45500-45512. [PMID: 27275537 PMCID: PMC5216737 DOI: 10.18632/oncotarget.9787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/16/2016] [Indexed: 12/13/2022] Open
Abstract
Patients with actively replicating human immunodeficiency virus (HIV) exhibit adverse reactions even to low irradiation doses. High levels of the virus-encoded viral protein R (Vpr) are believed to be one of the major underlying causes for increased radiosensitivity. As Vpr efficiently crosses the blood-brain barrier and accumulates in astrocytes, we examined its efficacy as a drug for treatment of glioblastoma multiforme (GBM). In vitro, four glioblastoma-derived cell lines with and without methylguanine-DNA methyltransferase (MGMT) overexpression (U251, U87, U251-MGMT, U87-MGMT) were exposed to Vpr, temozolomide (TMZ), conventional photon irradiation (2 to 6 Gy) or to combinations thereof. Vpr showed high rates of acute toxicities with median effective doses of 4.0±1.1 μM and 15.7±7.5 μM for U251 and U87 cells, respectively. Caspase assays revealed Vpr-induced apoptosis in U251, but not in U87 cells. Vpr also efficiently inhibited clonogenic survival in both U251 and U87 cells and acted additively with irradiation. In contrast to TMZ, Vpr acted independently of MGMT expression. Dose escalation in mice (n=12) was feasible and resulted in no evident renal or liver toxicity. Both, irradiation with 3×5 Gy (n=8) and treatment with Vpr (n=5) delayed intracerebral tumor growth and prolonged overall survival compared to untreated animals (n=5; p3×5 Gy<0.001 and pVpr=0.04; log-rank test). Our data show that the HIV-encoded peptide Vpr exhibits all properties of an effective chemotherapeutic drug and may be a useful agent in the treatment of GBM.
Collapse
Affiliation(s)
- Jens Kübler
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefanie Kirschner
- Department of Neuroradiology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Linda Hartmann
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Grit Welzel
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Maren Engelhardt
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Institute of Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Carsten Herskind
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Marlon R Veldwijk
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christian Schultz
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Institute of Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Manuela Felix
- Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gerhard Glatting
- Medical Radiation Physics/Radiation Protection, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Patrick Maier
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Marc A Brockmann
- Department of Neuroradiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Frank A Giordano
- Department of Radiation Oncology, Universitätsmedizin Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| |
Collapse
|
3
|
Iijima K, Kobayashi J, Ishizaka Y. Structural alteration of DNA induced by viral protein R of HIV-1 triggers the DNA damage response. Retrovirology 2018; 15:8. [PMID: 29338752 PMCID: PMC5771197 DOI: 10.1186/s12977-018-0391-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/04/2018] [Indexed: 11/10/2022] Open
Abstract
Background Viral protein R (Vpr) is an accessory protein of HIV-1, which is potentially involved in the infection of macrophages and the induction of the ataxia-telangiectasia and Rad3-related protein (ATR)-mediated DNA damage response (DDR). It was recently proposed that the SLX4 complex of structure-specific endonuclease is involved in Vpr-induced DDR, which implies that aberrant DNA structures are responsible for this phenomenon. However, the mechanism by which Vpr alters the DNA structures remains unclear. Results We found that Vpr unwinds double-stranded DNA (dsDNA) and invokes the loading of RPA70, which is a single-stranded DNA-binding subunit of RPA that activates the ATR-dependent DDR. We demonstrated that Vpr influenced RPA70 to accumulate in the corresponding region utilizing the LacO/LacR system, in which Vpr can be tethered to the LacO locus. Interestingly, RPA70 recruitment required chromatin remodelling via Vpr-mediated ubiquitination of histone H2B. On the contrary, Q65R mutant of Vpr, which lacks ubiquitination activity, was deficient in both chromatin remodelling and RPA70 loading on to the chromatin. Moreover, Vpr-induced unwinding of dsDNA coincidently resulted in the accumulation of negatively supercoiled DNA and covalent complexes of topoisomerase 1 and DNA, which caused DNA double-strand breaks (DSBs) and DSB-directed integration of proviral DNA. Lastly, we noted the dependence of Vpr-promoted HIV-1 infection in resting macrophages on topoisomerase 1. Conclusions The findings of this study indicate that Vpr-induced structural alteration of DNA is a primary event that triggers both DDR and DSB, which ultimately contributes to HIV-1 infection. Electronic supplementary material The online version of this article (10.1186/s12977-018-0391-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Kenta Iijima
- Department of Intractable Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Junya Kobayashi
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Yukihito Ishizaka
- Department of Intractable Diseases, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan.
| |
Collapse
|
4
|
Doi A, Iijima K, Kano S, Ishizaka Y. Viral protein R of HIV type-1 induces retrotransposition and upregulates glutamate synthesis by the signal transducer and activator of transcription 1 signaling pathway. Microbiol Immunol 2016; 59:398-409. [PMID: 25990091 DOI: 10.1111/1348-0421.12266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/11/2015] [Accepted: 05/14/2015] [Indexed: 02/05/2023]
Abstract
Viral protein R (Vpr) of HIV-1 plays an important role in viral replication in macrophages. Various lines of evidence suggest that expression of Vpr in macrophages causes immunopathogenesis; however, the underlying mechanism is not yet fully understood. In this study, it was shown that recombinant Vpr (rVpr) induces retrotransposition of long interspersed element-1 in RAW264.7, a macrophage-like cell line, and activates reverse transcriptase-dependent immunotoxic cascades including production of IFN-β and phosphorylation of signal transducer and activator of transcription 1 (STAT1). Knockout experiments based on the CRISPR/Cas9 nickase system further demonstrated that cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) and stimulator of interferon gene (STING) are responsible for IFN-β production and STAT1 phosphorylation, respectively. Moreover, rVpr was found to increase production of glutaminase C, a regulator of glutamate synthesis, which is also dependent on the cGAS-STING pathway. Taken together with reports that glutaminase C is involved in the pathogenesis of HIV-associated neurocognitive disorder (HAND) and that Vpr is detectable in the cerebrospinal fluid of HIV-1-positive patients, a possible role of Vpr-induced L1-RTP and immunotoxic cascades in the development of HAND is discussed.
Collapse
Affiliation(s)
- Akihiro Doi
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-0052.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, 305-0006.,Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo, 102-0083
| | - Kenta Iijima
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-0052
| | - Shigeyuki Kano
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, 305-0006.,Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-0052, Japan
| | - Yukihito Ishizaka
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-0052
| |
Collapse
|
5
|
Hassan MS, Morgan AM, Mekawy MM, Zaki AR, Ghazi ZM. Teratogenic effect of cisplatin in rats and the protective role of sodium selenate. ACTA ACUST UNITED AC 2016; 68:277-87. [PMID: 26968388 DOI: 10.1016/j.etp.2016.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/13/2016] [Accepted: 02/26/2016] [Indexed: 10/22/2022]
Abstract
Eighty pregnant Sprague-Dawley rats were used in this study. They were allotted to four equal groups. The first group served as a control without any treatment while the other groups were given cisplatin, sodium selenate, and cisplatin+sodium selenate, respectively. Cisplatin was injected intraperitoneally in a dose of 5mg/kgb wt. on the 12th day of gestation while sodium selenate was administered orally in a dose of 0.5mg/kgb wt throughout gestation. Animals were sacrificed on the 20th day of gestation for fetal examination. Cisplatin produced significant elevation in the percentages of late resorption sites and dead foetuses compared with the control group. The mean foetal and placental weights were significantly reduced. Dwarf foetuses and subcutaneous (s/c) haemorrhage were also recorded in cisplatin-treated group. Visceral abnormalities were revealed in the form of dilated nares, anophthalmia and/or microphthalmia, dilated brain ventricles, hypertrophy of the heart, hypoplasia of the lung, hepatomegaly and dilated renal pelvis. Skeletal examination showed wide open fontanel, incomplete ossification of parietal and interparietal bones, incomplete ossification of sternum, reduction in the number or even complete absence of phalanges, sacral and/or caudal vertebrae. Histopathological examination of placentas in cisplatin-treated group revealed severe pathological alterations. Administration of sodium selenate significantly alleviated the afore-mentioned adverse effects of cisplatin on the fetuses and their placentas so we conclude that sodium selenate as an antioxidant has an effective protective role in cisplatin teratogenic effects.
Collapse
Affiliation(s)
- Mohammed S Hassan
- Toxicology and Forensic Medicine Department, Faculty of Veterinary Medicine, Cairo University, Egypt
| | - Ashraf M Morgan
- Toxicology and Forensic Medicine Department, Faculty of Veterinary Medicine, Cairo University, Egypt
| | - Mohey M Mekawy
- Toxicology and Forensic Medicine Department, Faculty of Veterinary Medicine, Cairo University, Egypt
| | - Amr R Zaki
- Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Beni-Suef University, Egypt.
| | - Zeinab M Ghazi
- Zoology Department, Faculty of Science, Omar Al-Mukhtar University, Libya
| |
Collapse
|
6
|
Kogan M, Deshmane S, Sawaya BE, Gracely EJ, Khalili K, Rappaport J. Inhibition of NF-κB activity by HIV-1 Vpr is dependent on Vpr binding protein. J Cell Physiol 2013; 228:781-90. [PMID: 23001849 DOI: 10.1002/jcp.24226] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 09/06/2012] [Indexed: 01/22/2023]
Abstract
Numerous studies have reported that Vpr alters NF-κB signaling in various cell types, however, the findings have been largely conflicting with reports of both stimulatory and inhibitory effects of Vpr. Our aim was to investigate the role of Vpr signaling in myeloid cells using an adenovirus based expression and indicator system. Our results show that Vpr is inhibitory to NF-κB, however, this effect is dependent on the particular manner of NF-κB stimulation. Consistent with this notion, we report that Vpr has inhibitory effects that are specific to the TNF-α pathway, but not affecting the LPS pathway, suggesting that differential targets of Vpr may exist for NF-κB regulation. Further, we identify VprBP as one possible cellular component of Vpr's regulation of IκBα in response to TNF-α stimulation. We did not identify such a role for HSP27, which instead seems to inhibit Vpr functions. Chronically HIV-1 infected U1 cells with knockdown constructs for Vpr were unexpectedly less responsive to TNF-α mediated viral replication, perhaps suggesting that other HIV-1 components may antagonize these anti-NF-κB effects in infected cells. We hypothesize that Vpr may serve an important role in the context of viral infection and immune function in vivo, through its selective inhibition of NF-κB pathways.
Collapse
Affiliation(s)
- Michael Kogan
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
| | | | | | | | | | | |
Collapse
|
7
|
Huang CY, Chiang SF, Lin TY, Chiou SH, Chow KC. HIV-1 Vpr triggers mitochondrial destruction by impairing Mfn2-mediated ER-mitochondria interaction. PLoS One 2012; 7:e33657. [PMID: 22438978 DOI: 10.1371/journal.pone.0033657] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 02/17/2012] [Indexed: 11/19/2022] Open
Abstract
Human immunodeficiency virus 1 (HIV-1) viral protein R (Vpr) has been shown to induce host cell death by increasing the permeability of mitochondrial outer membrane (MOM). The mechanism underlying the damage to the mitochondria by Vpr, however, is not clearly illustrated. In this study, Vpr that is introduced, via transient transfection or lentivirus infection, into the human embryonic kidney cell line HEK293, human CD4+ T lymphoblast cell line SupT1, or human primary CD4+ T cells serves as the model system to study the molecular mechanism of Vpr-mediated HIV-1 pathogenesis. The results show that Vpr injures MOM and causes a loss in membrane potential (MMP) by posttranscriptionally reducing the expression of mitofusin 2 (Mfn2) via VprBP-DDB1-CUL4A ubiquitin ligase complex, gradually weakening MOM, and increasing mitochondrial deformation. Vpr also markedly decreases cytoplasmic levels of dynamin-related protein 1 (DRP1) and increases bulging in mitochondria-associated membranes (MAM), the specific regions of endoplasmic reticulum (ER) which form physical contacts with the mitochondria. Overexpression of Mfn2 and DRP1 significantly decreased the loss of MMP and apoptotic cell death caused by Vpr. Furthermore, by employing time-lapse confocal fluorescence microscopy, we identify the transport of Vpr protein from the ER, via MAM to the mitochondria. Taken together, our results suggest that Vpr-mediated cellular damage may occur on an alternative protein transport pathway from the ER, via MAM to the mitochondria, which are modulated by Mfn2 and DRP1.
Collapse
|
8
|
Greiner VJ, Shvadchak V, Fritz J, Arntz Y, Didier P, Frisch B, Boudier C, Mély Y, de Rocquigny H. Characterization of the mechanisms of HIV-1 Vpr(52–96) internalization in cells. Biochimie 2011; 93:1647-58. [DOI: 10.1016/j.biochi.2011.05.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 05/31/2011] [Indexed: 02/08/2023]
|
9
|
Muthumani K, Lambert VM, Kawalekar O, Heller R, Kim JJ, Weiner DB, Ugen KE. Anti-cancer activity of the HIV accessory molecule viral protein R (Vpr): Delivery as a DNA expression plasmid or biologically active peptides. Vaccine 2010; 28:2005-10. [PMID: 20188256 DOI: 10.1016/j.vaccine.2009.10.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
By virtue of its ability to induce cell cycle arrest and apoptosis, the HIV accessory protein Vpr (viral protein R) has been evaluated by us and others as an anti-proliferative/anti-cancer agent. We have demonstrated that Vpr, when delivered to established experimental B16.F10 melanoma tumors in mice as a DNA expression plasmid through in vivo electroporation, can result in complete regression of the established tumors. We have also demonstrated that Vpr peptides from the carboxy region of the protein can inhibit in vitro growth of both B16.F10 melanoma as well as human HeLa cervical carcinoma tumor cells. These findings, summarized in this report, underscore the potential of Vpr as an anti-cancer agent and warrants, we believe, further experimental as well as clinical evaluation.
Collapse
Affiliation(s)
- Karrupiah Muthumani
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, United States
| | | | | | | | | | | | | |
Collapse
|
10
|
Abstract
Like most viral regulatory proteins, HIV-1 Vpr and homologous proteins from primate lentiviruses are small and multifunctional. They are associated with a plethora of effects and functions, including induction of cell cycle arrest in the G(2) phase, induction of apoptosis, transactivation, enhancement of the fidelity of reverse transcription, and nuclear import of viral DNA in macrophages and other nondividing cells. This review focuses on the cellular proteins that have been reported to interact with Vpr and their significance with respect to the known functions and effects of Vpr on cells and on viral replication.
Collapse
Affiliation(s)
- Vicente Planelles
- Division of Cell Biology and Immunology, Department of Pathology, University of Utah School of Medicine, 15 North Medical Drive East #2100-Room 2520, Salt Lake City, Utah 84112, USA.
| | | |
Collapse
|
11
|
Nonaka M, Hashimoto Y, Takeshima SN, Aida Y. The human immunodeficiency virus type 1 Vpr protein and its carboxy-terminally truncated form induce apoptosis in tumor cells. Cancer Cell Int 2009; 9:20. [PMID: 19674438 PMCID: PMC2735735 DOI: 10.1186/1475-2867-9-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 08/12/2009] [Indexed: 01/19/2023] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) accessory protein Vpr induces apoptosis after cell cycle arrest at the G2 phase in primate cells. We have reported previously that C81, a carboxy-terminally truncated form of Vpr, interferes with cell proliferation and results in apoptosis without G2 arrest. Here, we investigated whether this property of Vpr and C81 could be exploited for use as a potential anticancer agent. First, we demonstrated that C81 induced G1 arrest and apoptosis in all tumor cells tested. In contrast, Vpr resulted in G2 arrest and apoptosis in HeLa and 293 T cells. Vpr also suppressed the damaged-DNA-specific binding protein 1 (DDB1) in HepG2 cells, thereby inducing apoptosis without G2 arrest. G2 arrest was restored when DDB1 was overexpressed in cells that also expressed Vpr. Surprisingly, C81 induced G2 arrest when DDB1 was overexpressed in HepG2 cells, but not in HeLa or 293 T cells. Thus, the induction of Vpr- and C81-mediated cell cycle arrest appears to depend on the cell type, whereas apoptosis was observed in all tumor cells tested. Overall, Vpr and C81 have potential as novel therapeutic agents for treatment of cancer.
Collapse
Affiliation(s)
- Mizuho Nonaka
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | | | | | | |
Collapse
|
12
|
Rom I, Deshmane SL, Mukerjee R, Khalili K, Amini S, Sawaya BE. HIV-1 Vpr deregulates calcium secretion in neural cells. Brain Res 2009; 1275:81-6. [PMID: 19328187 DOI: 10.1016/j.brainres.2009.03.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 03/06/2009] [Accepted: 03/08/2009] [Indexed: 02/07/2023]
Abstract
The lack of productive infection of neurons by HIV-1 suggests that the neuronal damage seen in AIDS patients with cognitive disorders is caused indirectly via viral and cellular proteins with neurotoxic activity. Among HIV-1 proteins, Vpr has been shown to deregulate expression of various important cytokines and inflammatory proteins in infected and uninfected cells. However, the mechanisms underlying these changes remain unclear. Here, we demonstrate that neurons can take up Vpr that is released into the supernatant of HIV-infected microglia. We also found that administration of recombinant Vpr (rVpr) to human neurons resulted in a slow but sustained elevation of intracellular calcium [Ca(2+)]i. Interestingly, our data also show that [Ca(2+)]i elevation by Vpr leads to ROS production and impairs glutamate signaling in neuronal cells. Vpr disturbs calcium homeostasis through downregulation of endogenous PMCA. Finally, we found that the permeability of the plasma membrane increases in neurons treated with Vpr. Therefore, we conclude that soluble Vpr is a major viral factor that causes a disturbance in neuronal communication leading to neuronal dysfunction. The outcome of these studies will advance the understanding of HIV-1 pathogenesis and will help in the development of new therapeutic approaches.
Collapse
Affiliation(s)
- Inna Rom
- Department of Neuroscience and Center for Neurovirology, Temple University School of Medicine, 1900 North 12th Street, Philadelphia, PA 19122, USA
| | | | | | | | | | | |
Collapse
|