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Iyer H, Wahul AB, P K A, Sawant BS, Kumar A. A BRD's (BiRD's) eye view of BET and BRPF bromodomains in neurological diseases. Rev Neurosci 2021; 32:403-426. [PMID: 33661583 DOI: 10.1515/revneuro-2020-0067] [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: 07/08/2020] [Accepted: 10/11/2020] [Indexed: 01/18/2023]
Abstract
Neurological disorders (NLDs) are among the top leading causes for disability worldwide. Dramatic changes in the epigenetic topography of the brain and nervous system have been found in many NLDs. Histone lysine acetylation has prevailed as one of the well characterised epigenetic modifications in these diseases. Two instrumental components of the acetylation machinery are the evolutionarily conserved Bromodomain and PHD finger containing (BRPF) and Bromo and Extra terminal domain (BET) family of proteins, also referred to as acetylation 'readers'. Several reasons, including their distinct mechanisms of modulation of gene expression and their property of being highly tractable small molecule targets, have increased their translational relevance. Thus, compounds which demonstrated promising results in targeting these proteins have advanced to clinical trials. They have been established as key role players in pathologies of cancer, cardiac diseases, renal diseases and rheumatic diseases. In addition, studies implicating the role of these bromodomains in NLDs are gaining pace. In this review, we highlight the findings of these studies, and reason for the plausible roles of all BET and BRPF members in NLDs. A comprehensive understanding of their multifaceted functions would be radical in the development of therapeutic interventions.
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Affiliation(s)
- Harish Iyer
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Abhipradnya B Wahul
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Annapoorna P K
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Bharvi S Sawant
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Arvind Kumar
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
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2
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Jackson TC, Kochanek PM. RNA Binding Motif 5 (RBM5) in the CNS-Moving Beyond Cancer to Harness RNA Splicing to Mitigate the Consequences of Brain Injury. Front Mol Neurosci 2020; 13:126. [PMID: 32765218 PMCID: PMC7381114 DOI: 10.3389/fnmol.2020.00126] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022] Open
Abstract
Gene splicing modulates the potency of cell death effectors, alters neuropathological disease processes, influences neuronal recovery, but may also direct distinct mechanisms of secondary brain injury. Therapeutic targeting of RNA splicing is a promising avenue for next-generation CNS treatments. RNA-binding proteins (RBPs) regulate a variety of RNA species and are prime candidates in the hunt for druggable targets to manipulate and tailor gene-splicing responses in the brain. RBPs preferentially recognize unique consensus sequences in targeted mRNAs. Also, RBPs often contain multiple RNA-binding domains (RBDs)—each having a unique consensus sequence—suggesting the possibility that drugs could be developed to block individual functional domains, increasing the precision of RBP-targeting therapies. Empirical characterization of most RBPs is lacking and represents a major barrier to advance this emerging therapeutic area. There is a paucity of data on the role of RBPs in the brain including, identification of their unique mRNA targets, defining how CNS insults affect their levels and elucidating which RBPs (and individual domains within) to target to improve neurological outcomes. This review focuses on the state-of-the-art of the RBP tumor suppressor RNA binding motif 5 (RBM5) in the CNS. We discuss its potent pro-death roles in cancer, which motivated our interest to study it in the brain. We review recent studies showing that RBM5 levels are increased after CNS trauma and that it promotes neuronal death in vitro. Finally, we conclude with recent reports on the first set of RBM5 regulated genes identified in the intact brain, and discuss how those findings provide new clues germane to its potential function(s) in the CNS, and pose new questions on its therapeutic utility to mitigate CNS injury.
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Affiliation(s)
- Travis C Jackson
- Morsani College of Medicine, USF Health Heart Institute, University of South Florida, Tampa, FL, United States.,Morsani College of Medicine, Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, United States
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research, Department of Critical Care Medicine, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Jackson TC, Du L, Janesko-Feldman K, Vagni VA, Dezfulian C, Poloyac SM, Jackson EK, Clark RSB, Kochanek PM. The nuclear splicing factor RNA binding motif 5 promotes caspase activation in human neuronal cells, and increases after traumatic brain injury in mice. J Cereb Blood Flow Metab 2015; 35:655-66. [PMID: 25586139 PMCID: PMC4420885 DOI: 10.1038/jcbfm.2014.242] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/06/2014] [Accepted: 12/08/2014] [Indexed: 12/31/2022]
Abstract
Splicing factors (SFs) coordinate nuclear intron/exon splicing of RNA. Splicing factor disturbances can cause cell death. RNA binding motif 5 (RBM5) and 10 (RBM10) promote apoptosis in cancer cells by activating detrimental alternative splicing of key death/survival genes. The role(s) of RBM5/10 in neurons has not been established. Here, we report that RBM5 knockdown in human neuronal cells decreases caspase activation by staurosporine. In contrast, RBM10 knockdown augments caspase activation. To determine whether brain injury alters RBM signaling, we measured RBM5/10 protein in mouse cortical/hippocampus homogenates after controlled cortical impact (CCI) traumatic brain injury (TBI) plus hemorrhagic shock (CCI+HS). The RBM5/10 staining was higher 48 to 72 hours after injury and appeared to be increased in neuronal nuclei of the hippocampus. We also measured levels of other nuclear SFs known to be essential for cellular viability and report that splicing factor 1 (SF1) but not splicing factor 3A (SF3A) decreased 4 to 72 hours after injury. Finally, we confirm that RBM5/10 regulate protein expression of several target genes including caspase-2, cellular FLICE-like inhibitory protein (c-FLIP), LETM1 Domain-Containing Protein 1 (LETMD1), and amyloid precursor-like protein 2 (APLP2) in neuronal cells. Knockdown of RBM5 appeared to increase expression of c-FLIP(s), LETMD1, and APLP2 but decrease caspase-2.
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Affiliation(s)
- Travis C Jackson
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Lina Du
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Keri Janesko-Feldman
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Vincent A Vagni
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Cameron Dezfulian
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Samuel M Poloyac
- Pharmaceutical Sciences Department, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, USA
| | - Edwin K Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Robert S B Clark
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Patrick M Kochanek
- Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Yang LY, Chu YH, Tweedie D, Yu QS, Pick CG, Hoffer BJ, Greig NH, Wang JY. Post-trauma administration of the pifithrin-α oxygen analog improves histological and functional outcomes after experimental traumatic brain injury. Exp Neurol 2015; 269:56-66. [PMID: 25819102 DOI: 10.1016/j.expneurol.2015.03.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 03/13/2015] [Accepted: 03/17/2015] [Indexed: 01/10/2023]
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Programmed death of neuronal cells plays a crucial role in acute and chronic neurodegeneration following TBI. The tumor suppressor protein p53, a transcription factor, has been recognized as an important regulator of apoptotic neuronal death. The p53 inactivator pifithrin-α (PFT-α) has been shown to be neuroprotective against stroke. A previous cellular study indicated that PFT-α oxygen analog (PFT-α (O)) is more stable and active than PFT-α. We aimed to investigate whether inhibition of p53 using PFT-α or PFT-α (O) would be a potential neuroprotective strategy for TBI. To evaluate whether these drugs protect against excitotoxicity in vitro, primary rat cortical cultures were challenged with glutamate (50mM) in the presence or absence of various concentrations of the p53 inhibitors PFT-α or PFT-α (O). Cell viability was estimated by LDH assay. In vivo, adult Sprague Dawley rats were subjected to controlled cortical impact (CCI, with 4m/s velocity, 2mm deformation). Five hours after injury, PFT-α or PFT-α (O) (2mg/kg, i.v.) was administered to animals. Sensory and motor functions were evaluated by behavioral tests at 24h after TBI. The p53-positive neurons were identified by double staining with cell-specific markers. Levels of mRNA encoding for p53-regulated genes (BAX, PUMA, Bcl-2 and p21) were measured by reverse transcription followed by real time-PCR from TBI animals without or with PFT-α/PFT-α (O) treatment. We found that PFT-α(O) (10 μM) enhanced neuronal survival against glutamate-induced cytotoxicity in vitro more effectively than PFT-α (10 μM). In vivo PFT-α (O) treatment enhanced functional recovery and decreased contusion volume at 24h post-injury. Neuroprotection by PFT-α (O) treatment also reduced p53-positive neurons in the cortical contusion region. In addition, p53-regulated PUMA mRNA levels at 8h were significantly reduced by PFT-α (O) administration after TBI. PFT-α (O) treatment also decreased phospho-p53 positive neurons in the cortical contusion region. Our data suggest that PFT-α (O) provided a significant reduction of cortical cell death and protected neurons from glutamate-induced excitotoxicity in vitro, as well as improved neurological functional outcome and reduced brain injury in vivo via anti-apoptotic mechanisms. The inhibition of p53-induced apoptosis by PFT-α (O) provides a useful tool to evaluate reversible apoptotic mechanisms and may develop into a novel therapeutic strategy for TBI.
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Affiliation(s)
- L-Y Yang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Y-H Chu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - D Tweedie
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, USA
| | - Q-S Yu
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, USA
| | - C G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - B J Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - N H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, USA
| | - J-Y Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Abstract
Although p53 is a major cancer preventive factor, under certain extreme stress conditions it may induce severe pathologies. Analyses of animal models indicate that p53 is largely responsible for the toxicity of ionizing radiation or DNA damaging drugs contributing to hematopoietic component of acute radiation syndrome and largely determining severe adverse effects of cancer treatment. p53-mediated damage is strictly tissue specific and occurs in tissues prone to p53-dependent apoptosis (e.g., hematopoietic system and hair follicles); on the contrary, p53 can serve as a survival factor in tissues that respond to p53 activation by cell cycle arrest (e.g., endothelium of small intestine). There are multiple experimental indications that p53 contributes to pathogenicity of acute ischemic diseases. Temporary reversible suppression of p53 by small molecules can be an effective and safe approach to reduce severity of p53-associated pathologies.
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Affiliation(s)
- Andrei V Gudkov
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA.
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Gudkov AV, Komarova EA. Prospective therapeutic applications of p53 inhibitors. Biochem Biophys Res Commun 2005; 331:726-36. [PMID: 15865929 DOI: 10.1016/j.bbrc.2005.03.153] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Indexed: 10/25/2022]
Abstract
p53, in addition to being a key cancer preventive factor, is also a determinant of cancer treatment side effects causing excessive apoptotic death in several normal tissues during cancer therapy. p53 inhibitory strategy has been suggested to protect normal tissues from chemo- and radiotherapy, and to treat other pathologies associated with stress-mediated activation of p53. This strategy was validated by isolation and testing of small molecule p53 inhibitor pifithrin-alpha that demonstrated broad tissue protecting capacity. However, in some normal tissues and tumors p53 plays protective role by inducing growth arrest and preventing cells from premature entrance into mitosis and death from mitotic catastrophe. Inhibition of this function of p53 can sensitize tumor cells to chemo- and radiotherapy, thus opening new potential application of p53 inhibitors and justifying the need in pharmacological agents targeting specifically either pro-apoptotic or growth arrest functions of p53.
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Affiliation(s)
- Andrei V Gudkov
- Department of Molecular Genetics, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
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Tohda M, Watanabe H. Molecular cloning and characterization of a novel sequence, vof-16, with enhanced expression in permanent ischemic rat brain. Biol Pharm Bull 2005; 27:1228-35. [PMID: 15305027 DOI: 10.1248/bpb.27.1228] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We reported previously that chronic hypoperfusion induced by permanent occlusion of the bilateral common carotid arteries (2VO) in rats caused progressive cognitive deficits and neuronal damage in the hippocampus and the white matter. These changes are similar to those observed in human dementia. Reverse transcription-polymerase chain reaction (RT-PCR) differential display was carried out to identify mRNAs encoding the intrinsic factors involved in permanent ischemia from the 2VO rat brain. Over 20 clones which showed different expression levels in 2VO and sham-operated rats were isolated. One of these, named vof-16, was markedly enhanced the expression by 2VO. The whole sequence of vof-16 mRNA was 2098 nt. The distribution of vof-16 transcripts was examined by RT-PCR and in situ hybridization. The results revealed that vof-16 was abundant in the hippocampus, the tenia tecta, the piriform cortex and the area around the aorta. The expression levels of vof-16 in 2VO and sham-operated rat hippocampus were determined by a quantitative PCR method. The expression was abundant in the hippocampus of rats with cognitive impairment induced by 2VO. In contrast, the expression levels of vof-16 were lower in the 2VO rats with no impairment and in sham-operated rats. These results suggest that the expression levels of vof-16 may be related to the cognitive impairment induced by chronic ischemia after 2VO.
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Affiliation(s)
- Michihisa Tohda
- Department of Pharmacology, Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
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Komarova EA, Gudkov AV. Chemoprotection from p53-dependent apoptosis: potential clinical applications of the p53 inhibitors. Biochem Pharmacol 2001; 62:657-67. [PMID: 11556286 DOI: 10.1016/s0006-2952(01)00733-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The p53 tumor suppressor pathway is a key mediator of stress response that protects the organism from accumulating genetically altered and potentially cancerous cells by inducing growth arrest or apoptosis in damaged cells. However, under certain stressful conditions, p53 activity can result in massive apoptosis in sensitive tissues, leading to severe pathological consequences for the organism. One such situation is anticancer therapy that is often associated with general genotoxic stress, leading to p53-dependent apoptosis in the epithelia of the digestive tract and in the hematopoietic system. A chemical inhibitor of p53, capable of suppressing p53-mediated apoptosis, was shown to protect mice from lethal doses of gamma-radiation, making pharmacological suppression of p53 a perspective therapeutic approach to reduce the side-effects of cancer treatment. There are other situations, besides anti-cancer therapy, when humans are exposed to stressful conditions known to involve p53 activation, which, in extreme cases, could result in the development of life-threatening diseases. Here we review the experimental evidence on the role of p53 in tissue injuries associated with hypoxia (heart and brain ischemias) and hyperthermia (fever and burns), comparing these pathologies with the consequences of genotoxic stress of cancer treatment. The accumulated information points to the involvement of p53 in the generation of the pathological outcome of the above stresses, making them potential targets for the therapeutic application of p53 inhibitors.
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Affiliation(s)
- E A Komarova
- Department of Molecular Genetics, College of Medicine, University of Illinois at Chicago, 60607, USA
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Maeda K, Hata R, Gillardon F, Hossmann KA. Aggravation of brain injury after transient focal ischemia in p53-deficient mice. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 88:54-61. [PMID: 11295231 DOI: 10.1016/s0169-328x(01)00017-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The transcriptional factor p53 is a regulatory protein which contributes to the preservation of tissue integrity by promoting either DNA repair or apoptosis. To establish the pathophysiological role of this protein in ischemia, we produced 1 h transient middle cerebral artery (MCA) occlusion in normal and in p53-deficient mice and investigated the resulting tissue damage by multiparametric imaging. Possible genetic influences on the angioarchitecture of the MCA territory and blood flow were examined by intravascular latex infusion and laser-Doppler flowmetry. Wild-type (p53(+/+)), heterozygous (p53(+/-)) and homozygous (p53(-/-)) mice deficient for the p53 gene did not differ in respect to angioarchitecture or the effect of vascular occlusion on blood flow and general physiological parameters. Twenty-four hours after 1 h MCA occlusion, mice revealed a gene dose-dependent decline in the size of metabolic disturbances (ATP depletion and inhibition of protein synthesis) and histological injury (Cresyl Violet staining). DNA fragmentations detected by terminal deoxynucleotidyl transferase-mediated UTP nick end labeling (TUNEL) did not differ in the three groups and were only present in ATP-depleted tissue. Our findings suggest that after transient focal brain ischemia p53 prevents rather than aggravates brain injury, and that this effect is brought about by mechanisms that are unrelated to the pro-apoptotic properties of this gene.
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Affiliation(s)
- K Maeda
- Max-Planck-Institute for Neurological Research, Department of Experimental Neurology, Gleueler Strasse 50, D-50931 Cologne, Germany
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