1
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Haemmerle MW, Scota AV, Khosravifar M, Varney MJ, Sen S, Good AL, Yang X, Wells KL, Sussel L, Rozo AV, Doliba NM, Ghanem LR, Stoffers DA. RNA-binding protein PCBP2 regulates pancreatic β cell function and adaptation to glucose. J Clin Invest 2024; 134:e172436. [PMID: 38950317 PMCID: PMC11178539 DOI: 10.1172/jci172436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 04/23/2024] [Indexed: 07/03/2024] Open
Abstract
Glucose plays a key role in shaping pancreatic β cell function. Thus, deciphering the mechanisms by which this nutrient stimulates β cells holds therapeutic promise for combating β cell failure in type 2 diabetes (T2D). β Cells respond to hyperglycemia in part by rewiring their mRNA metabolism, yet the mechanisms governing these changes remain poorly understood. Here, we identify a requirement for the RNA-binding protein PCBP2 in maintaining β cell function basally and during sustained hyperglycemic challenge. PCBP2 was induced in primary mouse islets incubated with elevated glucose and was required to adapt insulin secretion. Transcriptomic analysis of primary Pcbp2-deficient β cells revealed impacts on basal and glucose-regulated mRNAs encoding core components of the insulin secretory pathway. Accordingly, Pcbp2-deficient β cells exhibited defects in calcium flux, insulin granule ultrastructure and exocytosis, and the amplification pathway of insulin secretion. Further, PCBP2 was induced by glucose in primary human islets, was downregulated in islets from T2D donors, and impacted genes commonly altered in islets from donors with T2D and linked to single-nucleotide polymorphisms associated with T2D. Thus, these findings establish a paradigm for PCBP2 in governing basal and glucose-adaptive gene programs critical for shaping the functional state of β cells.
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Affiliation(s)
- Matthew W. Haemmerle
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Andrea V. Scota
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Mina Khosravifar
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew J. Varney
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Sabyasachi Sen
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Austin L. Good
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xiaodun Yang
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Lori Sussel
- Department of Pediatrics and
- Department of Cell & Developmental Biology, and
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Andrea V. Rozo
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nicolai M. Doliba
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Louis R. Ghanem
- Division of Gastroenterology, Hepatology and Nutrition Division, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Doris A. Stoffers
- Institute for Diabetes, Obesity, and Metabolism and Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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2
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Jiang L, Zheng H, Ishida M, Lyu Q, Akatsuka S, Motooka Y, Sato K, Sekido Y, Nakamura K, Tanaka H, Ishikawa K, Kajiyama H, Mizuno M, Hori M, Toyokuni S. Elaborate cooperation of poly(rC)-binding proteins 1/2 and glutathione in ferroptosis induced by plasma-activated Ringer's lactate. Free Radic Biol Med 2024; 214:28-41. [PMID: 38325565 DOI: 10.1016/j.freeradbiomed.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/29/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
Reactive species are involved in various aspects of neoplastic diseases, including carcinogenesis, cancer-specific metabolism and therapeutics. Non-thermal plasma (NTP) can directly provide reactive species, by integrating atmospheric and interjacent molecules as substrates, to represent a handy strategy to load oxidative stress in situ. NTP causes apoptosis and/or ferroptosis specifically in cancer cells of various types. Plasma-activated Ringer's lactate (PAL) is another modality at the preclinical stage as cancer therapeutics, based on more stable reactive species. PAL specifically kills malignant mesothelioma (MM) cells, employing lysosomal ·NO as a switch from autophagy to ferroptosis. However, the entire molecular mechanisms have not been elucidated yet. Here we studied cytosolic iron regulations in MM and other cancer cells in response to PAL exposure. We discovered that cells with higher catalytic Fe(II) are more susceptible to PAL-induced ferroptosis. PAL caused a cytosolic catalytic Fe(II)-associated pathology through iron chaperones, poly (rC)-binding proteins (PCBP)1/2, inducing a disturbance in glutathione-regulated iron homeostasis. PCBP1/NCOA4-mediated ferritinophagy started at a later phase, further increasing cytosolic catalytic Fe(II), ending in ferroptosis. In contrast, PCBP2 after PAL exposure contributed to iron loading to mitochondria, leading to mitochondrial dysfunction. Therapeutic effect of PAL was successfully applied to an orthotopic MM xenograft model in mice. In conclusion, PAL can selectively sensitize MM cells to ferroptosis by remodeling cytoplasmic iron homeostasis, where glutathione and PCBPs play distinct roles, resulting in lethal ferritinophagy and mitochondrial dysfunction. Our findings indicate the clinical application of PAL as a ferroptosis-inducer and the potential of PCBPs as novel targets in cancer therapeutics.
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Affiliation(s)
- Li Jiang
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Hao Zheng
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Moe Ishida
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Qinying Lyu
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Shinya Akatsuka
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Yashiro Motooka
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Kotaro Sato
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan; Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-Ku, Nagoya, 466-8550, Japan
| | - Yoshitaka Sekido
- Division of Cancer Biology, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya, 464-8681, Japan
| | - Kae Nakamura
- Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan; Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-Ku, Nagoya, 466-8550, Japan
| | - Hiromasa Tanaka
- Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan; Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, 65 Tsurumai-cho, Showa-Ku, Nagoya, 466-8550, Japan
| | - Kenji Ishikawa
- Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan
| | - Hiroaki Kajiyama
- Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan; Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-Ku, Nagoya, 466-8550, Japan
| | - Masaaki Mizuno
- Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, 65 Tsurumai-cho, Showa-Ku, Nagoya, 466-8550, Japan
| | - Masaru Hori
- Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan
| | - Shinya Toyokuni
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan; Center for Low-temperature Plasma Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8603, Japan; Center for Integrated Sciences of Low-temperature Plasma Core Research (iPlasma Core), Tokai National Higher Education and Research System, Furo-Cho, Chikusa-ku, Nagoya, 464-8603, Japan.
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3
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Sato J, Satoh Y, Yamamoto T, Watanabe T, Matsubara S, Satake H, Kimura AP. PTBP2 binds to a testis-specific long noncoding RNA, Tesra, and activates transcription of the Prss42/Tessp-2 gene. Gene 2024; 893:147907. [PMID: 37858745 DOI: 10.1016/j.gene.2023.147907] [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: 08/11/2023] [Revised: 09/22/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
Long noncoding RNAs (lncRNAs) have recently been proved to be functional in the testis. Tesra, a testis-specific lncRNA, was suggested to activate the transcription of Prss42/Tessp-2, a gene that is involved in meiotic progression, in mouse spermatocytes. To reveal the molecular mechanism underlying the activation, we searched for Tesra-binding proteins by a Ribotrap assay followed by LC-MS/MS analysis and identified polypyrimidine tract binding protein 2 (PTBP2) as a candidate. Analysis of public RNA-seq data and our qRT-PCR results indicated that Ptbp2 mRNA showed an expression pattern similar to the expression patterns of Tesra and Prss42/Tessp-2 during testis development. Moreover, PTBP2 was found to be associated with Tesra in testicular germ cells by RNA immunoprecipitation. To evaluate the effect of PTBP2 on the Prss42/Tessp-2 promoter, we established an in vitro reporter gene assay system in which Tesra expression could be induced by the Tet-on system and thereby Prss42/Tessp-2 promoter activity could be increased. In this system, the Prss42/Tessp-2 promoter activity was significantly decreased by the knockdown of PTBP2. These results suggest that PTBP2 contributes to Prss42/Tessp-2 transcriptional activation by Tesra in spermatocytes. The finding provides a precious example of a molecular mechanism of testis lncRNA functioning in spermatogenesis.
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Affiliation(s)
- Josei Sato
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Yui Satoh
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Takehiro Yamamoto
- Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan
| | - Takehiro Watanabe
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Shin Matsubara
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Atsushi P Kimura
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan.
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4
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Nishikawa S, Watanabe H, Terasaka N, Katoh T, Fujishima K. De Novo Single-Stranded RNA-Binding Peptides Discovered by Codon-Restricted mRNA Display. Biomacromolecules 2024; 25:355-365. [PMID: 38051119 PMCID: PMC10777347 DOI: 10.1021/acs.biomac.3c01024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/07/2023]
Abstract
RNA-binding proteins participate in diverse cellular processes, including DNA repair, post-transcriptional modification, and cancer progression through their interactions with RNAs, making them attractive for biotechnological applications. While nature provides an array of naturally occurring RNA-binding proteins, developing de novo RNA-binding peptides remains challenging. In particular, tailoring peptides to target single-stranded RNA with low complexity is difficult due to the inherent structural flexibility of RNA molecules. Here, we developed a codon-restricted mRNA display and identified multiple de novo peptides from a peptide library that bind to poly(C) and poly(A) RNA with KDs ranging from micromolar to submicromolar concentrations. One of the newly identified peptides is capable of binding to the cytosine-rich sequences of the oncogenic Cdk6 3'UTR RNA and MYU lncRNA, with affinity comparable to that of the endogenous binding protein. Hence, we present a novel platform for discovering de novo single-stranded RNA-binding peptides that offer promising avenues for regulating RNA functions.
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Affiliation(s)
- Shota Nishikawa
- Earth-Life
Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- School
of Life Science and Technology, Tokyo Institute
of Technology, Meguro-ku, Tokyo 152-8550, Japan
| | - Hidenori Watanabe
- Earth-Life
Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Naohiro Terasaka
- Earth-Life
Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Takayuki Katoh
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kosuke Fujishima
- Earth-Life
Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Graduate
School of Media and Governance, Keio University, Fujisawa 252-0882, Japan
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5
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Muranov KO. Fenton Reaction in vivo and in vitro. Possibilities and Limitations. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:S112-S126. [PMID: 38621747 DOI: 10.1134/s0006297924140074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 04/17/2024]
Abstract
The review considers the problem of hydrogen peroxide decomposition and hydroxyl radical formation in the presence of iron in vivo and in vitro. Analysis of the literature data allows us to conclude that, under physiological conditions, transport of iron, carried out with the help of carrier proteins, minimizes the possibility of appearance of free iron ions in cytoplasm of the cell. Under pathological conditions, when the process of transferring an iron ion from a donor protein to an acceptor protein can be disrupted due to modifications of the carrier proteins, iron ions can enter cytosol. However, at pH values close to neutral, which is typical for cytosol, iron ions are converted into water-insoluble hydroxides. This makes it impossible to decompose hydrogen peroxide according to the mechanism of the classical Fenton reaction. A similar situation is observed in vitro, since buffers with pH close to neutral are used to simulate free radical oxidation. At the same time, iron hydroxides are able to catalyze decomposition of hydrogen peroxide with formation of a hydroxyl radical. Decomposition of hydrogen peroxide with iron hydroxides is called Fenton-like reaction. Studying the features of Fenton-like reaction in biological systems is the subject of future research.
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Affiliation(s)
- Konstantin O Muranov
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia.
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6
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Wang Y, Protchenko O, Huber KD, Shakoury-Elizeh M, Ghosh MC, Philpott CC. The iron chaperone poly(rC)-binding protein 1 regulates iron efflux through intestinal ferroportin in mice. Blood 2023; 142:1658-1671. [PMID: 37624904 PMCID: PMC10656723 DOI: 10.1182/blood.2023020504] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/28/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
Iron is an essential nutrient required by all cells but used primarily for red blood cell production. Because humans have no effective mechanism for ridding the body of excess iron, the absorption of dietary iron must be precisely regulated. The critical site of regulation is the transfer of iron from the absorptive enterocyte to the portal circulation via the sole iron efflux transporter, ferroportin. Here, we report that poly(rC)-binding protein 1 (PCBP1), the major cytosolic iron chaperone, is necessary for the regulation of iron flux through ferroportin in the intestine of mice. Mice lacking PCBP1 in the intestinal epithelium exhibit low levels of enterocyte iron, poor retention of dietary iron in enterocyte ferritin, and excess efflux of iron through ferroportin. Excess iron efflux occurred despite lower levels of ferroportin protein in enterocytes and upregulation of the iron regulatory hormone hepcidin. PCBP1 deletion and the resulting unregulated dietary iron absorption led to poor growth, severe anemia on a low-iron diet, and liver oxidative stress with iron loading on a high-iron diet. Ex vivo culture of PCBP1-depleted enteroids demonstrated no defects in hepcidin-mediated ferroportin turnover. However, measurement of kinetically labile iron pools in enteroids competent or blocked for iron efflux indicated that PCBP1 functioned to bind and retain cytosolic iron and limit its availability for ferroportin-mediated efflux. Thus, PCBP1 coordinates enterocyte iron and reduces the concentration of unchaperoned "free" iron to a low level that is necessary for hepcidin-mediated regulation of ferroportin activity.
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Affiliation(s)
- Yubo Wang
- Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Olga Protchenko
- Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Kari D. Huber
- Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Minoo Shakoury-Elizeh
- Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Manik C. Ghosh
- Section on Human Iron Metabolism, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Caroline C. Philpott
- Genetics and Metabolism Section, Liver Diseases Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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7
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Lu YW, Liang Z, Guo H, Fernandes T, Espinoza-Lewis RA, Wang T, Li K, Li X, Singh GB, Wang Y, Cowan D, Mably JD, Philpott CC, Chen H, Wang DZ. PCBP1 regulates alternative splicing of AARS2 in congenital cardiomyopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.18.540420. [PMID: 37293078 PMCID: PMC10245752 DOI: 10.1101/2023.05.18.540420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Alanyl-transfer RNA synthetase 2 (AARS2) is a nuclear encoded mitochondrial tRNA synthetase that is responsible for charging of tRNA-Ala with alanine during mitochondrial translation. Homozygous or compound heterozygous mutations in the Aars2 gene, including those affecting its splicing, are linked to infantile cardiomyopathy in humans. However, how Aars2 regulates heart development, and the underlying molecular mechanism of heart disease remains unknown. Here, we found that poly(rC) binding protein 1 (PCBP1) interacts with the Aars2 transcript to mediate its alternative splicing and is critical for the expression and function of Aars2. Cardiomyocyte-specific deletion of Pcbp1 in mice resulted in defects in heart development that are reminiscent of human congenital cardiac defects, including noncompaction cardiomyopathy and a disruption of the cardiomyocyte maturation trajectory. Loss of Pcbp1 led to an aberrant alternative splicing and a premature termination of Aars2 in cardiomyocytes. Additionally, Aars2 mutant mice with exon-16 skipping recapitulated heart developmental defects observed in Pcbp1 mutant mice. Mechanistically, we found dysregulated gene and protein expression of the oxidative phosphorylation pathway in both Pcbp1 and Aars2 mutant hearts; these date provide further evidence that the infantile hypertrophic cardiomyopathy associated with the disorder oxidative phosphorylation defect type 8 (COXPD8) is mediated by Aars2. Our study therefore identifies Pcbp1 and Aars2 as critical regulators of heart development and provides important molecular insights into the role of disruptions in metabolism on congenital heart defects.
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8
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Lee J, Hyun DH. The Interplay between Intracellular Iron Homeostasis and Neuroinflammation in Neurodegenerative Diseases. Antioxidants (Basel) 2023; 12:antiox12040918. [PMID: 37107292 PMCID: PMC10135822 DOI: 10.3390/antiox12040918] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/23/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
Iron is essential for life. Many enzymes require iron for appropriate function. However, dysregulation of intracellular iron homeostasis produces excessive reactive oxygen species (ROS) via the Fenton reaction and causes devastating effects on cells, leading to ferroptosis, an iron-dependent cell death. In order to protect against harmful effects, the intracellular system regulates cellular iron levels through iron regulatory mechanisms, including hepcidin-ferroportin, divalent metal transporter 1 (DMT1)-transferrin, and ferritin-nuclear receptor coactivator 4 (NCOA4). During iron deficiency, DMT1-transferrin and ferritin-NCOA4 systems increase intracellular iron levels via endosomes and ferritinophagy, respectively. In contrast, repleting extracellular iron promotes cellular iron absorption through the hepcidin-ferroportin axis. These processes are regulated by the iron-regulatory protein (IRP)/iron-responsive element (IRE) system and nuclear factor erythroid 2-related factor 2 (Nrf2). Meanwhile, excessive ROS also promotes neuroinflammation by activating the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). NF-κB forms inflammasomes, inhibits silent information regulator 2-related enzyme 1 (SIRT1), and induces pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β). Furthermore, 4-hydroxy-2,3-trans-nonenal (4-HNE), the end-product of ferroptosis, promotes the inflammatory response by producing amyloid-beta (Aβ) fibrils and neurofibrillary tangles in Alzheimer's disease, and alpha-synuclein aggregation in Parkinson's disease. This interplay shows that intracellular iron homeostasis is vital to maintain inflammatory homeostasis. Here, we review the role of iron homeostasis in inflammation based on recent findings.
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Affiliation(s)
- Jaewang Lee
- Department of Life Science, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Dong-Hoon Hyun
- Department of Life Science, Ewha Womans University, Seoul 03760, Republic of Korea
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9
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Montañés-Agudo P, Pinto YM, Creemers EE. Splicing factors in the heart: Uncovering shared and unique targets. J Mol Cell Cardiol 2023; 179:72-79. [PMID: 37059416 DOI: 10.1016/j.yjmcc.2023.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/29/2023] [Accepted: 04/09/2023] [Indexed: 04/16/2023]
Abstract
Alternative splicing generates specialized protein isoforms that allow the heart to adapt during development and disease. The recent discovery that mutations in the splicing factor RNA-binding protein 20 (RBM20) cause a severe form of familial dilated cardiomyopathy has sparked a great interest in alternative splicing in the field of cardiology. Since then, identification of splicing factors controlling alternative splicing in the heart has grown at a rapid pace. Despite the intriguing observation that a certain overlap exists between the targets of some splicing factors, an integrated and systematic analysis of their splicing networks is missing. Here, we compared the splicing networks of individual splicing factors by re-analyzing original RNA-sequencing data from eight previously published mouse models, in which a single splicing factor has been genetically deleted (i.e. HNRNPU, MBNL1/2, QKI, RBM20, RBM24, RBPMS, SRSF3, SRSF4). We show that key splicing events in Camk2d, Ryr2, Tpm1, Tpm2 and Pdlim5 require the combined action of the majority of these splicing factors. Additionally, we identified common targets and pathways among splicing factors, with the largest overlap between the splicing networks of MBNL, QKI and RBM24. We also re-analyzed a large-scale RNA-sequencing study on hearts of 128 heart failure patients. Here, we observed that MBNL1, QKI and RBM24 expression varied greatly. This variation in expression correlated with differential splicing of their downstream targets as found in mice, suggesting that aberrant splicing by MBNL1, QKI and RBM24 might contribute to the disease mechanism in heart failure.
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Affiliation(s)
- Pablo Montañés-Agudo
- Experimental Cardiology, Room K2-112, Amsterdam UMC Location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
| | - Yigal M Pinto
- Experimental Cardiology, Room K2-104, Amsterdam UMC, location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
| | - Esther E Creemers
- Experimental Cardiology, Room K2-104-2, Amsterdam UMC, Location University of Amsterdam, Meibergdreef 15, Amsterdam 1105AZ, the Netherlands.
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10
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Philpott CC, Protchenko O, Wang Y, Novoa-Aponte L, Leon-Torres A, Grounds S, Tietgens AJ. Iron-tracking strategies: Chaperones capture iron in the cytosolic labile iron pool. Front Mol Biosci 2023; 10:1127690. [PMID: 36818045 PMCID: PMC9932599 DOI: 10.3389/fmolb.2023.1127690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 01/23/2023] [Indexed: 02/05/2023] Open
Abstract
Cells express hundreds of iron-dependent enzymes that rely on the iron cofactors heme, iron-sulfur clusters, and mono-or di-nuclear iron centers for activity. Cells require systems for both the assembly and the distribution of iron cofactors to their cognate enzymes. Proteins involved in the binding and trafficking of iron ions in the cytosol, called cytosolic iron chaperones, have been identified and characterized in mammalian cells. The first identified iron chaperone, poly C-binding protein 1 (PCBP1), has also been studied in mice using genetic models of conditional deletion in tissues specialized for iron handling. Studies of iron trafficking in mouse tissues have necessitated the development of new approaches, which have revealed new roles for PCBP1 in the management of cytosolic iron. These approaches can be applied to investigate use of other nutrient metals in mammals.
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11
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Martinelli M, Aguilar G, Lee DS, Kromer A, Nguyen N, Wilkins BJ, Akimova T, Beier UH, Ghanem LR. The poly(C)-binding protein Pcbp2 is essential for CD4 + T cell activation and proliferation. iScience 2022; 26:105860. [PMID: 36632062 PMCID: PMC9826892 DOI: 10.1016/j.isci.2022.105860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/16/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022] Open
Abstract
The RNA-binding protein Pcbp2 is widely expressed in the innate and adaptive immune systems and is essential for mouse development. To determine whether Pcbp2 is required for CD4+ T cell development and function, we derived mice with conditional Pcbp2 deletion in CD4+ T cells and assessed their overall phenotype and proliferative responses to activating stimuli. We found that Pcbp2 is essential for T conventional cell (Tconv) proliferation, working through regulation of co-stimulatory signaling. Pcbp2 deficiency in the CD4+ lineage did not impact Treg abundance in vivo or function in vitro. In addition, our data demonstrate a clear association between Pcbp2 control of Runx1 exon 6 splicing in CD4+ T cells and a specific role for Pcbp2 in the maintenance of peripheral CD4+ lymphocyte population size. Last, we show that Pcbp2 function is required for optimal in vivo Tconv cell activation in a T cell adoptive transfer colitis model system.
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Affiliation(s)
- Massimo Martinelli
- Division of Gastroenterology, Hepatology and Nutrition Division, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA,Department of Translational Medical Science, Section of Pediatrics, University of Naples “Federico II”, Naples 80131, Italy
| | - Gabrielle Aguilar
- Division of Gastroenterology, Hepatology and Nutrition Division, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - David S.M. Lee
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA,Institute for Biomedical Informatics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew Kromer
- Division of Gastroenterology, Hepatology and Nutrition Division, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nhu Nguyen
- Division of Gastroenterology, Hepatology and Nutrition Division, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Benjamin J. Wilkins
- Division of Anatomic Pathology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA,Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tatiana Akimova
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ulf H. Beier
- Division of Nephrology, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Louis R. Ghanem
- Division of Gastroenterology, Hepatology and Nutrition Division, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA,Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA,Corresponding author
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12
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Malaney P, Benitez O, Zhang X, Post SM. Assessing the role of intrinsic disorder in RNA-binding protein function: hnRNP K as a case study. Methods 2022; 208:59-65. [DOI: 10.1016/j.ymeth.2022.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/20/2022] [Accepted: 10/26/2022] [Indexed: 11/09/2022] Open
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13
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Generation of PCBP1-deficient pigs using CRISPR/Cas9-mediated gene editing. iScience 2022; 25:105268. [PMID: 36274935 PMCID: PMC9579030 DOI: 10.1016/j.isci.2022.105268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/16/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
Classical swine fever virus (CSFV), a classic swine fever pathogen, causes severe economic losses worldwide. Poly (rC)-binding protein 1 (PCBP1), which interacts with Npro of CSFV, plays a vital role in CSFV growth. We are the first to report the generation of PCBP1-deficient pigs via gene-editing technology. The PCBP1-deficient pigs exhibited normal birth weight and reproductive-performance traits and developed normally. Viral challenge experiments indicated that primary cells isolated from F0- and F1-generation pigs exhibited significantly reduced CSFV infection. Additional mechanistic exploration further confirmed that the PCBP1 deficiency-mediated antiviral effect is related to the activation of type I interferon (IFN). Besides showing that a gene-editing strategy could be used to generate PCBP1-deficient pigs, our study introduces a valuable animal model for further investigating the infection mechanisms of CSFV that will help to develop better antiviral solutions. Reduced CSFV infection in PCBP1-deficient cells is related to activated ISGs expression PCBP1-deficient pigs were successfully generated via gene-editing technology Primary cells isolated from PCBP1-deficient pigs exhibited reduced CSFV infection
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14
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Kotla NK, Dutta P, Parimi S, Das NK. The Role of Ferritin in Health and Disease: Recent Advances and Understandings. Metabolites 2022; 12:metabo12070609. [PMID: 35888733 PMCID: PMC9320524 DOI: 10.3390/metabo12070609] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 11/18/2022] Open
Abstract
Systemic iron homeostasis needs to be tightly controlled, as both deficiency and excess iron cause major global health concerns, such as iron deficiency anemia, hemochromatosis, etc. In mammals, sufficient dietary acquisition is critical for fulfilling the systemic iron requirement. New questions are emerging about whether and how cellular iron transport pathways integrate with the iron storage mechanism. Ferritin is the intracellular iron storage protein that stores surplus iron after all the cellular needs are fulfilled and releases it in the face of an acute demand. Currently, there is a surge in interest in ferritin research after the discovery of novel pathways like ferritinophagy and ferroptosis. This review emphasizes the most recent ferritin-related discoveries and their impact on systemic iron regulation.
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15
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Gu H, Yang J, Zhang J, Song Y, Zhang Y, Xu P, Zhu Y, Wang L, Zhang P, Li L, Chen D, Sun Q. PCBP2 maintains antiviral signaling homeostasis by regulating cGAS enzymatic activity via antagonizing its condensation. Nat Commun 2022; 13:1564. [PMID: 35322803 PMCID: PMC8943206 DOI: 10.1038/s41467-022-29266-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/07/2022] [Indexed: 02/07/2023] Open
Abstract
Cyclic GMP-AMP synthase (cGAS) plays a major role in detecting pathogenic DNA. It produces cyclic dinucleotide cGAMP, which subsequently binds to the adaptor protein STING and further triggers antiviral innate immune responses. However, the molecular mechanisms regulating cGAS enzyme activity remain largely unknown. Here, we characterize the cGAS-interacting protein Poly(rC)-binding protein 2 (PCBP2), which plays an important role in controlling cGAS enzyme activity, thereby mediating appropriate cGAS-STING signaling transduction. We find that PCBP2 overexpression reduces cGAS-STING antiviral signaling, whereas loss of PCBP2 significantly increases cGAS activity. Mechanistically, we show that PCBP2 negatively regulates anti-DNA viral signaling by specifically interacting with cGAS but not other components. Moreover, PCBP2 decreases cGAS enzyme activity by antagonizing cGAS condensation, thus ensuring the appropriate production of cGAMP and balancing cGAS-STING signal transduction. Collectively, our findings provide insight into how the cGAS-mediated antiviral signaling is regulated.
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Affiliation(s)
- Haiyan Gu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China.,Institute of Biomedical Research, Yunnan University, Kunming, 650500, China.,Institute of Stem Cells and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Yang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China
| | - Jiayu Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China.,Institute of Stem Cells and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.,School of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ying Song
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China
| | - Yao Zhang
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China
| | - Pengfei Xu
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China
| | - Yuanxiang Zhu
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China
| | - Liangliang Wang
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China
| | - Pengfei Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China
| | - Lin Li
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China.,Institute of Stem Cells and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dahua Chen
- Institute of Biomedical Research, Yunnan University, Kunming, 650500, China.
| | - Qinmiao Sun
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101, China. .,Institute of Stem Cells and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China. .,School of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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16
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Zhao H, Wei Z, Shen G, Chen Y, Hao X, Li S, Wang R. Poly(rC)-binding proteins as pleiotropic regulators in hematopoiesis and hematological malignancy. Front Oncol 2022; 12:1045797. [PMID: 36452487 PMCID: PMC9701828 DOI: 10.3389/fonc.2022.1045797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Poly(rC)-binding proteins (PCBPs), a defined subfamily of RNA binding proteins, are characterized by their high affinity and sequence-specific interaction with poly-cytosine (poly-C). The PCBP family comprises five members, including hnRNP K and PCBP1-4. These proteins share a relatively similar structure motif, with triple hnRNP K homology (KH) domains responsible for recognizing and combining C-rich regions of mRNA and single- and double-stranded DNA. Numerous studies have indicated that PCBPs play a prominent role in hematopoietic cell growth, differentiation, and tumorigenesis at multiple levels of regulation. Herein, we summarized the currently available literature regarding the structural and functional divergence of various PCBP family members. Furthermore, we focused on their roles in normal hematopoiesis, particularly in erythropoiesis. More importantly, we also discussed and highlighted their involvement in carcinogenesis, including leukemia and lymphoma, aiming to clarify the pleiotropic roles and molecular mechanisms in the hematopoietic compartment.
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Affiliation(s)
- Huijuan Zhao
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Ziqing Wei
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Guomin Shen
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Yixiang Chen
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang, China.,Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Xueqin Hao
- Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Sanqiang Li
- Basic Medical College, Henan University of Science and Technology, Luoyang, China
| | - Rong Wang
- Department of Clinical Laboratory, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, China
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17
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Jadhav S, Protchenko O, Li F, Baratz E, Shakoury-Elizeh M, Maschek A, Cox J, Philpott CC. Mitochondrial dysfunction in mouse livers depleted of iron chaperone PCBP1. Free Radic Biol Med 2021; 175:18-27. [PMID: 34455040 PMCID: PMC9137418 DOI: 10.1016/j.freeradbiomed.2021.08.232] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/05/2021] [Accepted: 08/25/2021] [Indexed: 12/20/2022]
Abstract
Iron is an essential nutrient that forms cofactors required for the activity of hundreds of cellular proteins. However, iron can be toxic and must be precisely managed. Poly r(C) binding protein 1 (PCBP1) is an essential, multifunctional protein that binds both iron and nucleic acids, regulating the fate of both. As an iron chaperone, PCBP1 binds cytosolic iron and delivers it to iron enzymes for activation and to ferritin for storage. Mice deleted for PCBP1 in the liver exhibit dysregulated iron balance, with lower levels of liver iron stores and iron enzymes, but higher levels of chemically-reactive iron. Unchaperoned iron triggers the formation of reactive oxygen species, leading to lipid peroxidation and ferroptotic cell death. Hepatic PCBP1 deletion produces chronic liver disease in mice, with steatosis, triglyceride accumulation, and elevated plasma ALT levels. Human and mouse models of fatty liver disease are associated with mitochondrial dysfunction. Here we show that, although deletion of PCBP1 does not affect mitochondrial iron balance, it does affect mitochondrial function. PCBP1 deletion affected mitochondrial morphology and reduced levels of respiratory complexes II and IV, oxygen consumption, and ATP production. Depletion of mitochondrial lipids cardiolipin and coenzyme Q, along with reduction of mitochondrial oxygen consumption, were the first manifestations of mitochondrial dysfunction. Although dietary supplementation with vitamin E ameliorated the liver disease in mice with hepatic PCBP1 deletion, supplementation with coenzyme Q was required to fully restore mitochondrial lipids and function. In conclusion, our studies indicate that mitochondrial function can be restored in livers subjected to ongoing oxidative damage from unchaperoned iron by supplementation with coenzyme Q, a mitochondrial lipid essential for respiration that also functions as a lipophilic radical-trapping agent.
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Affiliation(s)
| | - Olga Protchenko
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD, USA
| | - Fengmin Li
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD, USA
| | - Ethan Baratz
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD, USA
| | | | - Alan Maschek
- Dept. of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - James Cox
- Dept. of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
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18
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Liao CY, Lei CQ, Shu HB. PCBP1 modulates the innate immune response by facilitating the binding of cGAS to DNA. Cell Mol Immunol 2021; 18:2334-2343. [PMID: 32415261 PMCID: PMC8484664 DOI: 10.1038/s41423-020-0462-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 02/07/2023] Open
Abstract
Cyclic GMP-AMP synthase (cGAS) is a key sensor critical for the recognition of DNA in the cytosol and catalyzes the synthesis of the second messenger cyclic GMP-AMP (cGAMP), which binds to the adapter protein MITA (also known as STING, MPYS, and ERIS) to initiate the innate immune response. How the binding of DNA to and the activation of cGAS are regulated remains poorly understood. Using a biochemical purification approach, we identified poly(rC)-binding protein 1 (PCBP1) as a cGAS-associated protein. PCBP1 was recruited to cGAS in a viral infection-dependent manner. PCBP1 directly bound to DNA and enhanced cGAS binding to its ligands, which was important for cGAS activation. Consistently, PCBP1 deficiency inhibited cytosolic DNA- and DNA virus-triggered transcription of downstream effector genes. These findings suggest that PCBP1 plays an important role in the cGAS-mediated innate immune response to DNA virus infection by promoting the binding of cGAS to viral DNA.
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Affiliation(s)
- Chen-Yang Liao
- grid.49470.3e0000 0001 2331 6153Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071 Wuhan, China
| | - Cao-Qi Lei
- grid.49470.3e0000 0001 2331 6153Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071 Wuhan, China
| | - Hong-Bing Shu
- grid.49470.3e0000 0001 2331 6153Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, 430071 Wuhan, China
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19
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RNA-Binding Proteins PCBP1 and PCBP2 Are Critical Determinants of Murine Erythropoiesis. Mol Cell Biol 2021; 41:e0066820. [PMID: 34180713 PMCID: PMC8384066 DOI: 10.1128/mcb.00668-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We previously demonstrated that the two paralogous RNA-binding proteins PCBP1 and PCBP2 are individually essential for mouse development: Pcbp1-null embryos are peri-implantation lethal, while Pcbp2-null embryos lose viability at midgestation. Midgestation Pcbp2-/- embryos revealed a complex phenotype that included loss of certain hematopoietic determinants. Whether PCBP2 directly contributes to erythropoietic differentiation and whether PCBP1 has a role in this process remained undetermined. Here, we selectively inactivated the genes encoding these two RNA-binding proteins during differentiation of the erythroid lineage in the developing mouse embryo. Individual inactivation of either locus failed to impact viability or blood formation. However, combined inactivation of the two loci resulted in midgestational repression of erythroid/hematopoietic gene expression, loss of blood formation, and fetal demise. Orthogonal ex vivo analyses of primary erythroid progenitors selectively depleted of these two RNA-binding proteins revealed that they mediate a combination of overlapping and isoform-specific impacts on hematopoietic lineage transcriptome, impacting both mRNA representation and exon splicing. These data lead us to conclude that PCBP1 and PCBP2 mediate functions critical to differentiation of the erythroid lineage.
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20
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Protchenko O, Baratz E, Jadhav S, Li F, Shakoury-Elizeh M, Gavrilova O, Ghosh MC, Cox JE, Maschek JA, Tyurin VA, Tyurina YY, Bayir H, Aron AT, Chang CJ, Kagan VE, Philpott CC. Iron Chaperone Poly rC Binding Protein 1 Protects Mouse Liver From Lipid Peroxidation and Steatosis. Hepatology 2021; 73:1176-1193. [PMID: 32438524 PMCID: PMC8364740 DOI: 10.1002/hep.31328] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/06/2020] [Accepted: 04/24/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Iron is essential yet also highly chemically reactive and potentially toxic. The mechanisms that allow cells to use iron safely are not clear; defects in iron management are a causative factor in the cell-death pathway known as ferroptosis. Poly rC binding protein 1 (PCBP1) is a multifunctional protein that serves as a cytosolic iron chaperone, binding and transferring iron to recipient proteins in mammalian cells. Although PCBP1 distributes iron in cells, its role in managing iron in mammalian tissues remains open for study. The liver is highly specialized for iron uptake, utilization, storage, and secretion. APPROACH AND RESULTS Mice lacking PCBP1 in hepatocytes exhibited defects in liver iron homeostasis with low levels of liver iron, reduced activity of iron enzymes, and misregulation of the cell-autonomous iron regulatory system. These mice spontaneously developed liver disease with hepatic steatosis, inflammation, and degeneration. Transcriptome analysis indicated activation of lipid biosynthetic and oxidative-stress response pathways, including the antiferroptotic mediator, glutathione peroxidase type 4. Although PCBP1-deleted livers were iron deficient, dietary iron supplementation did not prevent steatosis; instead, dietary iron restriction and antioxidant therapy with vitamin E prevented liver disease. PCBP1-deleted hepatocytes exhibited increased labile iron and production of reactive oxygen species (ROS), were hypersensitive to iron and pro-oxidants, and accumulated oxidatively damaged lipids because of the reactivity of unchaperoned iron. CONCLUSIONS Unchaperoned iron in PCBP1-deleted mouse hepatocytes leads to production of ROS, resulting in lipid peroxidation (LPO) and steatosis in the absence of iron overload. The iron chaperone activity of PCBP1 is therefore critical for limiting the toxicity of cytosolic iron and may be a key factor in preventing the LPO that triggers the ferroptotic cell-death pathway.
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Affiliation(s)
| | - Ethan Baratz
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD
| | | | - Fengmin Li
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD
| | | | | | - Manik C. Ghosh
- Section on Human Iron Metabolism, NICHD, NIH, Bethesda, MD
| | - James E. Cox
- Deparment of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - J. Alan Maschek
- Deparment of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Vladimir A. Tyurin
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA
| | - Yulia Y. Tyurina
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA
| | - Hülya Bayir
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA
| | - Allegra T. Aron
- Department of Chemistry, University of California, Berkeley, CA
| | | | - Valerian E. Kagan
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA
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21
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Chen X, Yu C, Kang R, Tang D. Iron Metabolism in Ferroptosis. Front Cell Dev Biol 2020; 8:590226. [PMID: 33117818 PMCID: PMC7575751 DOI: 10.3389/fcell.2020.590226] [Citation(s) in RCA: 397] [Impact Index Per Article: 99.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/17/2020] [Indexed: 01/12/2023] Open
Abstract
Ferroptosis is a form of regulated cell death that is characterized by iron-dependent oxidative damage and subsequent plasma membrane ruptures and the release of damage-associated molecular patterns. Due to the role of iron in mediating the production of reactive oxygen species and enzyme activity in lipid peroxidation, ferroptosis is strictly controlled by regulators involved in many aspects of iron metabolism, such as iron uptake, storage, utilization, and efflux. Translational and transcriptional regulation of iron homeostasis provide an integrated network to determine the sensitivity of ferroptosis. Impaired ferroptosis is implicated in various iron-related pathological conditions or diseases, such as cancer, neurodegenerative diseases, and ischemia-reperfusion injury. Understanding the molecular mechanisms underlying the regulation of iron metabolism during ferroptosis may provide effective strategies for the treatment of ferroptosis-associated diseases. Indeed, iron chelators effectively prevent the occurrence of ferroptosis, which may provide new approaches for the treatment of iron-related disorders. In this review, we summarize recent advances in the theoretical modeling of iron-dependent ferroptosis, and highlight the therapeutic implications of iron chelators in diseases.
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Affiliation(s)
- Xin Chen
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, The Third Affiliated Hospital, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,Department of Surgery, UT Southwestern Medical Center, Dallas, TX, United States
| | - Chunhua Yu
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, United States
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, United States
| | - Daolin Tang
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, The Third Affiliated Hospital, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,Department of Surgery, UT Southwestern Medical Center, Dallas, TX, United States
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22
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Altamura S, Marques O, Colucci S, Mertens C, Alikhanyan K, Muckenthaler MU. Regulation of iron homeostasis: Lessons from mouse models. Mol Aspects Med 2020; 75:100872. [DOI: 10.1016/j.mam.2020.100872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/28/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
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23
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Ishii T, Igawa T, Hayakawa H, Fujita T, Sekiguchi M, Nakabeppu Y. PCBP1 and PCBP2 both bind heavily oxidized RNA but cause opposing outcomes, suppressing or increasing apoptosis under oxidative conditions. J Biol Chem 2020; 295:12247-12261. [PMID: 32647012 PMCID: PMC7443489 DOI: 10.1074/jbc.ra119.011870] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 07/06/2020] [Indexed: 12/18/2022] Open
Abstract
PCBP1, a member of the poly(C)-binding protein (PCBP) family, has the capability of binding heavily oxidized RNA and therefore participates in the cellular response to oxidative conditions, helping to induce apoptosis. There are four other members of this family, PCBP2, PCBP3, PCBP4, and hnRNPK, but it is not known whether they play similar roles. To learn more, we first tested their affinity for an RNA strand carrying two 8-oxoguanine (8-oxoG) residues at sites located in close proximity to each other, representative of a heavily oxidized strand or RNA with one 8-oxoG or none. Among them, only PCBP2 exhibited highly selective binding to RNA carrying two 8-oxoG residues similar to that observed with PCBP1. In contrast, PCBP3, PCBP4, and hnRNPK bound RNA with or without 8-oxoG modifications and exhibited slightly increased binding to the former. Mutations in conserved RNA-binding domains of PCBP2 disrupted the specific interaction with heavily oxidized RNA. We next tested PCBP2 activity in cells. Compared with WT HeLa S3 cells, PCBP2-KO cells established by gene editing exhibited increased apoptosis with increased caspase-3 activity and PARP1 cleavage under oxidative conditions, which were suppressed by the expression of WT PCBP2 but not one of the mutants lacking binding activity. In contrast, PCBP1-KO cells exhibited reduced apoptosis with much less caspase-3 activity and PARP cleavage than WT cells. Our results indicate that PCBP2 as well as PCBP1 bind heavily oxidized RNA; however, the former may counteract PCBP1 to suppress apoptosis under oxidative conditions.
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Affiliation(s)
- Takashi Ishii
- Department of Biochemistry, Fukuoka Dental College, Fukuoka, Japan; Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Tatsuhiro Igawa
- Frontier Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Hiroshi Hayakawa
- Department of Biochemistry, Fukuoka Dental College, Fukuoka, Japan
| | - Tsugumi Fujita
- Department of Biochemistry, Fukuoka Dental College, Fukuoka, Japan
| | - Mutsuo Sekiguchi
- Frontier Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
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24
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Philpott CC, Patel SJ, Protchenko O. Management versus miscues in the cytosolic labile iron pool: The varied functions of iron chaperones. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118830. [PMID: 32835748 DOI: 10.1016/j.bbamcr.2020.118830] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 01/01/2023]
Abstract
Iron-containing proteins rely on the incorporation of a set of iron cofactors for activity. The cofactors must be synthesized or assembled from raw materials located within the cell. The chemical nature of this pool of raw material - referred to as the labile iron pool - has become clearer with the identification of micro- and macro-molecules that coordinate iron within the cell. These molecules function as a buffer system for the management of intracellular iron and are the focus of this review, with emphasis on the major iron chaperone protein coordinating the labile iron pool: poly C-binding protein 1.
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Affiliation(s)
| | - Sarju J Patel
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD, USA
| | - Olga Protchenko
- Genetics and Metabolism Section, NIDDK, NIH, Bethesda, MD, USA
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25
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Mosleh E, Ou K, Haemmerle MW, Tembo T, Yuhas A, Carboneau BA, Townsend SE, Bosma KJ, Gannon M, O’Brien RM, Stoffers DA, Golson ML. Ins1-Cre and Ins1-CreER Gene Replacement Alleles Are Susceptible To Silencing By DNA Hypermethylation. Endocrinology 2020; 161:5817889. [PMID: 32267917 PMCID: PMC7354059 DOI: 10.1210/endocr/bqaa054] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 04/07/2020] [Indexed: 12/14/2022]
Abstract
Targeted gene ablation studies of the endocrine pancreas have long suffered from suboptimal Cre deleter strains. In many cases, Cre lines purportedly specific for beta cells also displayed expression in other islet endocrine cells or in a subset of neurons in the brain. Several pancreas and endocrine Cre lines have experienced silencing or mosaicism over time. In addition, many Cre transgenic constructs were designed to include the hGH mini-gene, which by itself increases beta-cell replication and decreases beta-cell function. More recently, driver lines with Cre or CreER inserted into the Ins1 locus were generated, with the intent of producing β cell-specific Cre lines with faithful recapitulation of insulin expression. These lines were bred in multiple labs to several different mouse lines harboring various lox alleles. In our hands, the ability of the Ins1-Cre and Ins1-CreER lines to delete target genes varied from that originally reported, with both alleles displaying low levels of expression, increased levels of methylation compared to the wild-type allele, and ultimately inefficient or absent target deletion. Thus, caution is warranted in the interpretation of results obtained with these genetic tools, and Cre expression and activity should be monitored regularly when using these lines.
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Affiliation(s)
- Elham Mosleh
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kristy Ou
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Matthew W Haemmerle
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Teguru Tembo
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Andrew Yuhas
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Bethany A Carboneau
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Shannon E Townsend
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Karin J Bosma
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Maureen Gannon
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- United States Department of Veteran Affairs, Nashville, Tennessee
| | - Richard M O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Doris A Stoffers
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Maria L Golson
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
- Correspondence: Maria L. Golson, PhD, 5501 Hopkins Bayview Circle, Baltimore, MD 21224. E-mail:
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Ansa-Addo EA, Huang HC, Riesenberg B, Iamsawat S, Borucki D, Nelson MH, Nam JH, Chung D, Paulos CM, Liu B, Yu XZ, Philpott C, Howe PH, Li Z. RNA binding protein PCBP1 is an intracellular immune checkpoint for shaping T cell responses in cancer immunity. SCIENCE ADVANCES 2020; 6:eaaz3865. [PMID: 32523987 PMCID: PMC7259945 DOI: 10.1126/sciadv.aaz3865] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/25/2020] [Indexed: 05/11/2023]
Abstract
Distinct lineages of T cells can act in response to various environmental cues to either drive or restrict immune-mediated pathology. Here, we identify the RNA binding protein, poly(C)-binding protein 1 (PCBP1) as an intracellular immune checkpoint that is up-regulated in activated T cells to prevent conversion of effector T (Teff) cells into regulatory T (Treg) cells, by restricting the expression of Teff cell-intrinsic Treg commitment programs. This was critical for stabilizing Teff cell functions and subverting immune-suppressive signals. T cell-specific deletion of Pcbp1 favored Treg cell differentiation, enlisted multiple inhibitory immune checkpoint molecules including PD-1, TIGIT, and VISTA on tumor-infiltrating lymphocytes, and blunted antitumor immunity. Our results demonstrate a critical role for PCBP1 as an intracellular immune checkpoint for maintaining Teff cell functions in cancer immunity.
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Affiliation(s)
- Ephraim A. Ansa-Addo
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
- Pelotonia Institute for Immuno-Oncology and Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center-James, Columbus, OH 43210, USA
| | - Huai-Cheng Huang
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
- National Taiwan University College of Medicine, Graduate Institute of Clinical Medicine, No.7 Chung San South Road, Taipei City 10002, Taiwan
| | - Brian Riesenberg
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
- Pelotonia Institute for Immuno-Oncology and Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center-James, Columbus, OH 43210, USA
| | - Supinya Iamsawat
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Davis Borucki
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Michelle H. Nelson
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jin Hyun Nam
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Dongjun Chung
- Pelotonia Institute for Immuno-Oncology and Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center-James, Columbus, OH 43210, USA
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Chrystal M. Paulos
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Bei Liu
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Xue-Zhong Yu
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Caroline Philpott
- Genetics and Metabolism Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, MD 20892, USA
| | - Philip H. Howe
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Zihai Li
- Department of Microbiology and Immunology and Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
- Pelotonia Institute for Immuno-Oncology and Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center-James, Columbus, OH 43210, USA
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Yabe-Wada T, Philpott CC, Onai N. PCBP2 post-transcriptionally regulates sortilin expression by binding to a C-rich element in its 3' UTR. FEBS Open Bio 2020; 10:407-413. [PMID: 31961070 PMCID: PMC7050257 DOI: 10.1002/2211-5463.12794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/24/2019] [Accepted: 01/16/2020] [Indexed: 12/22/2022] Open
Abstract
Post‐transcriptional regulation of cytokine production is crucial to ensure appropriate immune responses. We previously demonstrated that poly‐rC‐binding protein‐1 (PCBP1) can act as a trans‐acting factor to stabilize transcripts encoding sortilin, which mediates cytokine trafficking. Here, we report that PCBP2, which strongly resembles PCBP1, can stabilize sortilin transcripts in macrophages using the same mechanism employed by PCBP1. PCBP2 recognized the C‐rich element in the 3′ UTR of sortilin mRNA, and PCBP2 knockdown decreased sortilin transcripts, indicating that PCBP2 stabilizes sortilin mRNA by binding to its 3′ UTR. Zn2+ reversibly inhibited the nucleotide binding ability of PCBP2 in vitro. These findings suggest that both PCBP2 and PCBP1 may control the stability of sortilin transcripts by sensing intracellular Zn2+ levels in immune cells.
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Affiliation(s)
- Toshiki Yabe-Wada
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Japan.,Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Caroline C Philpott
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nobuyuki Onai
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Japan
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Expression patterns of pcbp gene family members during zebrafish embryogenesis. Gene Expr Patterns 2020; 35:119097. [PMID: 32007595 DOI: 10.1016/j.gep.2020.119097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/14/2020] [Accepted: 01/27/2020] [Indexed: 10/25/2022]
Abstract
The poly(C)-binding protein (PCBP) family members belong to a subtype of RNA-binding proteins that are ubiquitously expressed with diverse functions. In mammals, PCBP family, also known as hnRNP E family, is composed of four proteins, namely PCBP1, PCBP2, PCBP3 and PCBP4. So far, no study has been documented on the physiological roles of each member in vertebrate development. Here we analysed the spatiotemporal expression patterns of zebrafish (Danio rerio) pcbp2 (identical to pcbp1 and pcbp2 in mammals), pcbp3 and pcbp4 at various stages of zebrafish embryonic development by whole-mount in situ hybridization. Our results revealed that all pcbp genes are maternally expressed, especially pcbp2, which is strongly expressed from the embryogenetic stage to larva. The expression patterns of PCBP members are similar to each other at the very early developmental stage sharing with common strong expression in the intestine, otic vesicle, retina and brain of zebrafish. Subsequently, the messenger RNAs of PCBP members are gradually constrained and highly expressed in intestines of the larvae. Collectively, our study figured out the expression pattern of each PCBP member in diverse organogenesis during embryo development, indicating that PCBP members may play predominant roles in the development of neural and digestive systems to maintain their normal physiological functions. Moreover, the similar expression patterns at the developmental stages and organ types among this family suggest that the aberrant expression of these genes would lead to the neural or intestinal diseases.
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Yanatori I, Richardson DR, Toyokuni S, Kishi F. How iron is handled in the course of heme catabolism: Integration of heme oxygenase with intracellular iron transport mechanisms mediated by poly (rC)-binding protein-2. Arch Biochem Biophys 2019; 672:108071. [PMID: 31421070 DOI: 10.1016/j.abb.2019.108071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/05/2019] [Accepted: 08/10/2019] [Indexed: 02/07/2023]
Abstract
Heme and iron are essential to almost all forms of life. The strict maintenance of heme and iron homeostasis is essential to prevent cellular toxicity and the existence of systemic and intracellular regulation is fundamental. Cytosolic heme can be catabolized and detoxified by heme oxygenases (HOs). Interestingly, free heme detoxification through HOs results in the production of free ferrous iron, which can be potentially hazardous for cells. Recently, the intracellular iron chaperone, poly (rC)-binding protein 2 (PCBP2), has been identified, which can be involved in accepting iron after heme catabolism as well as intracellular iron transport. In fact, HO1, NADPH-cytochrome P450 reductase, and PCBP2 form a functional unit that integrates the catabolism of heme with the binding and transport of iron by PCBP2. In this review, we provide an overview of our understanding of the iron chaperones and discuss the mechanism how iron chaperones bind iron released during the process of heme degradation.
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Affiliation(s)
- Izumi Yanatori
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Japan
| | - Des R Richardson
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Japan; Department of Pathology and Bosch Institute, University of Sydney, Camperdown, Sydney, New South Wales, 2006, Australia
| | - Shinya Toyokuni
- Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Japan
| | - Fumio Kishi
- Kenjinkai Healthcare Corporation, 530 Asa, Sanyo-Onoda Yamaguchi, 757-0001, Japan.
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30
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Nazarov IB, Bakhmet EI, Tomilin AN. KH-Domain Poly(C)-Binding Proteins as Versatile Regulators of Multiple Biological Processes. BIOCHEMISTRY (MOSCOW) 2019; 84:205-219. [PMID: 31221059 DOI: 10.1134/s0006297919030039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Five known members of the family of KH-domain poly(C)-binding proteins (Pcbp1-4, hnRNP-K) have an unusually broad spectrum of cellular functions that include regulation of gene transcription, regulation of pre-mRNA processing, splicing, mRNA stability, translational silencing and enhancement, the control of iron turnover, and many others. Mechanistically, these proteins act via nucleic acid binding and protein-protein interactions. Through performing these multiple tasks, the KH-domain poly(C)-binding family members are involved in a wide variety of biological processes such as embryonic development, cell differentiation, and cancer. Deregulation of KH-domain protein expression is frequently associated with severe developmental defects and neoplasia. This review summarizes progress in studies of the KH-domain proteins made over past two decades. The review also reports our recent finding implying an involvement of the KH-factor Pcbp1 into control of transition from naïve to primed pluripotency cell state.
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Affiliation(s)
- I B Nazarov
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.
| | - E I Bakhmet
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - A N Tomilin
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
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31
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Mohibi S, Chen X, Zhang J. Cancer the'RBP'eutics-RNA-binding proteins as therapeutic targets for cancer. Pharmacol Ther 2019; 203:107390. [PMID: 31302171 DOI: 10.1016/j.pharmthera.2019.07.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/02/2019] [Indexed: 12/11/2022]
Abstract
RNA-binding proteins (RBPs) play a critical role in the regulation of various RNA processes, including splicing, cleavage and polyadenylation, transport, translation and degradation of coding RNAs, non-coding RNAs and microRNAs. Recent studies indicate that RBPs not only play an instrumental role in normal cellular processes but have also emerged as major players in the development and spread of cancer. Herein, we review the current knowledge about RNA binding proteins and their role in tumorigenesis as well as the potential to target RBPs for cancer therapeutics.
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Affiliation(s)
- Shakur Mohibi
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Xinbin Chen
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States
| | - Jin Zhang
- Comparative Oncology Laboratory, Schools of Veterinary Medicine and Medicine, University of California at Davis, United States.
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32
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Ishii T, Sekiguchi M. Two ways of escaping from oxidative RNA damage: Selective degradation and cell death. DNA Repair (Amst) 2019; 81:102666. [PMID: 31326364 DOI: 10.1016/j.dnarep.2019.102666] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Reactive oxygen species (ROS) are produced during normal cellular metabolism, and various oxidized compounds are formed by the ROS attack. Among oxidized bases, 8-oxo-7,8-dihydroguanine (8-oxoG) is most abundant and seems important with respect to the maintenance and transfer of genetic information. The accumulation of 8-oxoG in messenger RNA may cause errors during codon-anticodon pairing in the translation process, which may result in the synthesis of abnormal proteins. Organisms that use oxygen as the source of energy production must therefore have some mechanisms to eliminate the deleterious effects of RNA oxidation. Recently, we found two protein factors, AUF1 and PCBP1, which each have a different binding capacity to oxidized RNA. Evidence demonstrated that AUF1 is involved in the specific degradation of oxidized RNA, and that PCBP1 has a function of inducing cell death to eliminate severely damaged RNA.
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Affiliation(s)
- Takashi Ishii
- Department of Biochemistry, Fukuoka Dental College, Fukuoka 814-0193, Japan.
| | - Mutsuo Sekiguchi
- Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
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Abstract
Many past and recent advances in the field of iron metabolism have relied upon the discovery of divalent metal transporter 1, DMT1 in 1997. DMT1 is the major iron transporter and contributes non-heme iron uptake in most types of cell. Each DMT1 isoform exhibits different expression patterns in cell-type specificity and distinct subcellular distribution, which enables cells to uptake both transferrin-bound and non-transferrin-bound irons efficiently. DMT1 expression is regulated by iron through the translational and degradation pathways to ensure iron homeostasis. It is considered that mammalian iron transporters including DMT1 cannot transport ferric iron but ferrous iron. Being reduced to ferrous state is likely to damage cells and tissues through the production of reactive oxygen species. Recently, iron chaperones have been identified, which can provide an answer to how ferrous iron is transported safely in cytosol. We summarize DMT1 expression depending on the types of cell or tissue and the function and mechanism of one of the iron chaperones, PCBP2.
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Affiliation(s)
- Izumi Yanatori
- Department of Biochemistry, Stanford University, School of Medicine, 279 Campus Drive, Stanford, CA 94305-5307, USA
| | - Fumio Kishi
- Hagi Public Health and Welfare Center, Yamaguchi Prefectural Government, 531-1 Emukai, Hagi, Yamaguchi 758-0041, Japan.
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Sangkhae V, Nemeth E. Placental iron transport: The mechanism and regulatory circuits. Free Radic Biol Med 2019; 133:254-261. [PMID: 29981833 PMCID: PMC7059975 DOI: 10.1016/j.freeradbiomed.2018.07.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 02/06/2023]
Abstract
As the interface between the fetal and maternal circulation, the placenta facilitates both nutrient and waste exchange for the developing fetus. Iron is essential for healthy pregnancy, and transport of iron across the placenta is required for fetal growth and development. Perturbation of this transfer can lead to adverse pregnancy outcomes. Despite its importance, our understanding of how a large amount of iron is transported across placental membranes, how this process is regulated, and which iron transporter proteins function in different placental cells remains rudimentary. Mechanistic studies in mouse models, including placenta-specific deletion or overexpression of iron-related proteins will be essential to make progress. This review summarizes our current understanding about iron transport across the syncytiotrophoblast under physiological conditions and identifies areas for further investigation.
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Affiliation(s)
- Veena Sangkhae
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 LeConte Ave, CHS 37-131, Los Angeles, CA 90095, USA.
| | - Elizabeta Nemeth
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 LeConte Ave, CHS 37-131, Los Angeles, CA 90095, USA.
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35
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Ghanem LR, Kromer A, Silverman IM, Ji X, Gazzara M, Nguyen N, Aguilar G, Martinelli M, Barash Y, Liebhaber SA. Poly(C)-Binding Protein Pcbp2 Enables Differentiation of Definitive Erythropoiesis by Directing Functional Splicing of the Runx1 Transcript. Mol Cell Biol 2018; 38:e00175-18. [PMID: 29866654 PMCID: PMC6066754 DOI: 10.1128/mcb.00175-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/10/2018] [Accepted: 05/26/2018] [Indexed: 12/14/2022] Open
Abstract
Formation of the mammalian hematopoietic system is under a complex set of developmental controls. Here, we report that mouse embryos lacking the KH domain poly(C) binding protein, Pcbp2, are selectively deficient in the definitive erythroid lineage. Compared to wild-type controls, transcript splicing analysis of the Pcbp2-/- embryonic liver reveals accentuated exclusion of an exon (exon 6) that encodes a highly conserved transcriptional control segment of the hematopoietic master regulator, Runx1. Embryos rendered homozygous for a Runx1 locus lacking this cassette exon (Runx1ΔE6) effectively phenocopy the loss of the definitive erythroid lineage in Pcbp2-/- embryos. These data support a model in which enhancement of Runx1 cassette exon 6 inclusion by Pcbp2 serves a critical role in development of hematopoietic progenitors and constitutes a critical step in the developmental pathway of the definitive erythropoietic lineage.
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Affiliation(s)
- Louis R Ghanem
- Gastroenterology, Hepatology and Nutrition Division, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrew Kromer
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian M Silverman
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Xinjun Ji
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Matthew Gazzara
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nhu Nguyen
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Gabrielle Aguilar
- Gastroenterology, Hepatology and Nutrition Division, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Massimo Martinelli
- Gastroenterology, Hepatology and Nutrition Division, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Translational Medical Science, Section of Pediatrics, University of Naples Federico II, Naples, Italy
| | - Yoseph Barash
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen A Liebhaber
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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36
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Identification and Characterization of Sindbis Virus RNA-Host Protein Interactions. J Virol 2018; 92:JVI.02171-17. [PMID: 29321325 DOI: 10.1128/jvi.02171-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022] Open
Abstract
Arthropod-borne viruses, such as the members of the genus Alphavirus, are a significant concern to global public health. As obligate intracellular pathogens, RNA viruses must interact with the host cell machinery to establish and complete their life cycles. Despite considerable efforts to define the host-pathogen interactions essential for alphaviral replication, an unbiased and inclusive assessment of alphaviral RNA-protein interactions has not been undertaken. Moreover, the biological and molecular importance of these interactions, in the full context of their molecular function as RNA-binding proteins, has not been fully realized. The data presented here introduce a robust viral RNA-protein discovery method to elucidate the Sindbis virus (SINV) RNA-protein host interface. Cross-link-assisted mRNP purification (CLAMP) assessment revealed an extensive array of host-pathogen interactions centered on the viral RNAs (vRNAs). After prioritization of the host proteins associated with the vRNAs, we identified the site of protein-vRNA interaction by a UV cross-linking and immunoprecipitation sequencing (CLIP-seq) approach and assessed the consequences of the RNA-protein binding event of hnRNP K, hnRNP I, and hnRNP M in regard to viral infection. Here, we demonstrate that mutation of the prioritized hnRNP-vRNA interaction sites effectively disrupts hnRNP-vRNA interaction. Correlating with disrupted hnRNP-vRNA binding, SINV growth kinetics were reduced relative to wild-type parental viral infections in vertebrate and invertebrate tissue culture models of infection. The molecular mechanism leading to reduced viral growth kinetics was found to be dysregulated structural-gene expression. Collectively, this study further defines the scope and importance of the alphavirus host-pathogen vRNA-protein interactions.IMPORTANCE Members of the genus Alphavirus are widely recognized for their potential to cause severe disease. Despite this recognition, there are no antiviral therapeutics, or safe and effective vaccines, currently available to treat alphaviral infection. Alphaviruses utilize the host cell machinery to efficiently establish and complete their life cycle. However, the extent and importance of host-pathogen RNA-protein interactions are woefully undercharacterized. The efforts detailed in this study fill this critical gap, and the significance of this research is 3-fold. First, the data presented here fundamentally expand the scope and understanding of alphavirus host-pathogen interactions. Second, this study identifies the sites of interaction for several prioritized interactions and defines the contribution of the RNA-protein interaction at the molecular level. Finally, these studies build a strategy by which the importance of the given host-pathogen interactions may be assessed in the future, using a mouse model of infection.
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37
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Ji X, Humenik J, Yang D, Liebhaber SA. PolyC-binding proteins enhance expression of the CDK2 cell cycle regulatory protein via alternative splicing. Nucleic Acids Res 2018; 46:2030-2044. [PMID: 29253178 PMCID: PMC5829739 DOI: 10.1093/nar/gkx1255] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 11/13/2022] Open
Abstract
The PolyC binding proteins (PCBPs) impact alternative splicing of a subset of mammalian genes that are enriched in basic cellular functions. Here, we focus our analysis on PCBP-controlled cassette exon-splicing within the cell cycle control regulator cyclin-dependent kinase-2 (CDK2) transcript. We demonstrate that PCBP binding to a C-rich polypyrimidine tract (PPT) preceding exon 5 of the CDK2 transcript enhances cassette exon inclusion. This splice enhancement is U2AF65-independent and predominantly reflects actions of the PCBP1 isoform. Remarkably, PCBPs' control of CDK2 ex5 splicing has evolved subsequent to mammalian divergence via conversion of constitutive exon 5 inclusion in the mouse CDK2 transcript to PCBP-responsive exon 5 alternative splicing in humans. Importantly, exclusion of exon 5 from the hCDK2 transcript dramatically represses the expression of CDK2 protein with a corresponding perturbation in cell cycle kinetics. These data highlight a recently evolved post-transcriptional pathway in primate species with the potential to modulate cell cycle control.
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Affiliation(s)
- Xinjun Ji
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jesse Humenik
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daphne Yang
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen A Liebhaber
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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38
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Howley BV, Howe PH. TGF-beta signaling in cancer: post-transcriptional regulation of EMT via hnRNP E1. Cytokine 2018; 118:19-26. [PMID: 29396052 DOI: 10.1016/j.cyto.2017.12.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 12/29/2017] [Indexed: 12/12/2022]
Abstract
The TGFβ signaling pathway is a critical regulator of cancer progression in part through induction of the epithelial to mesenchymal transition (EMT). This process is aberrantly activated in cancer cells, facilitating invasion of the basement membrane, survival in the circulatory system, and dissemination to distant organs. The mechanisms through which epithelial cells transition to a mesenchymal state involve coordinated transcriptional and post-transcriptional control of gene expression. One such mechanism of control is through the RNA binding protein hnRNP E1, which regulates splicing and translation of a cohort of EMT and stemness-associated transcripts. A growing body of evidence indicates a major role for hnRNP E1 in the control of epithelial cell plasticity, especially in the context of carcinoma progression. Here, we review the multiple mechanisms through which hnRNP E1 functions to control EMT and metastatic progression.
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Affiliation(s)
- Breege V Howley
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Philip H Howe
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA.
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39
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Yanatori I, Richardson DR, Toyokuni S, Kishi F. The iron chaperone poly(rC)-binding protein 2 forms a metabolon with the heme oxygenase 1/cytochrome P450 reductase complex for heme catabolism and iron transfer. J Biol Chem 2017; 292:13205-13229. [PMID: 28655775 DOI: 10.1074/jbc.m117.776021] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/26/2017] [Indexed: 11/06/2022] Open
Abstract
Mammals incorporate a major proportion of absorbed iron as heme, which is catabolized by the heme oxygenase 1 (HO1)-NADPH-cytochrome P450 reductase (CPR) complex into biliverdin, carbon monoxide, and ferrous iron. Moreover, intestinal iron is incorporated as ferrous iron, which is transported via the iron importer, divalent metal transporter 1 (DMT1). Recently, we demonstrated that the iron chaperone poly(rC)-binding protein 2 (PCBP2) can directly receive ferrous iron from DMT1 or transfer iron to the iron exporter, ferroportin 1. To promote intracellular iron flux, an iron chaperone may be essential for receiving iron generated by heme catabolism, but this hypothesis is untested so far. Herein, we demonstrate that HO1 binds to PCBP2, but not to other PCBP family members, namely PCBP1, PCBP3, or PCBP4. Interestingly, HO1 formed a complex with either CPR or PCBP2, and it was demonstrated that PCBP2 competes with CPR for HO1 binding. Using PCBP2-deletion mutants, we demonstrated that the PCBP2 K homology 3 domain is important for the HO1/PCBP2 interaction. In heme-loaded cells, heme prompted HO1-CPR complex formation and decreased the HO1/PCBP2 interaction. Furthermore, in vitro reconstitution experiments with purified recombinant proteins indicated that HO1 could bind to PCBP2 in the presence of heme, whereas loading of PCBP2 with ferrous iron caused PCBP2 to lose its affinity for HO1. These results indicate that ferrous iron released from heme can be bound by PCBP2 and suggest a model for an integrated heme catabolism and iron transport metabolon.
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Affiliation(s)
- Izumi Yanatori
- From the Department of Molecular Genetics, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan
| | - Des R Richardson
- the Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia, and
| | - Shinya Toyokuni
- the Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia, and.,the Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Fumio Kishi
- From the Department of Molecular Genetics, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan,
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40
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Abstract
The regulation of iron metabolism in biological systems centers on providing adequate iron for cellular function while limiting iron toxicity. Because mammals cannot excrete iron, mechanisms have evolved to control iron acquisition, storage, and distribution at both systemic and cellular levels. Hepcidin, the master regulator of iron homeostasis, controls iron flows into plasma through inhibition of the only known mammalian cellular iron exporter ferroportin. Hepcidin is feedback-regulated by iron status and strongly modulated by inflammation and erythropoietic demand. This review highlights recent advances that have changed our understanding of iron metabolism and its regulation.
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Affiliation(s)
- Richard Coffey
- Departments of Medicine and Pathology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1690
| | - Tomas Ganz
- Departments of Medicine and Pathology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1690.
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41
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Espinoza-Lewis RA, Yang Q, Liu J, Huang ZP, Hu X, Chen D, Wang DZ. Poly(C)-binding protein 1 (Pcbp1) regulates skeletal muscle differentiation by modulating microRNA processing in myoblasts. J Biol Chem 2017; 292:9540-9550. [PMID: 28381556 DOI: 10.1074/jbc.m116.773671] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/04/2017] [Indexed: 11/06/2022] Open
Abstract
Regulation of gene expression during muscle development and disease remains incompletely understood. microRNAs are a class of small non-coding RNAs that regulate gene expression and function post-transcriptionally. The poly(C)-binding protein1 (Pcbp1, hnRNP-E1, or αCP-1) is an RNA-binding protein that has been reported to bind the 3'-UTRs of target genes to regulate mRNA stability and protein translation. However, Pcbp1's biological function and the general mechanism of action remain largely undetermined. Here, we report that Pcbp1 is a component of the miRNA-processing pathway that regulates miRNA biogenesis. siRNA-based inhibition of Pcbp1 in mouse skeletal muscle myoblasts led to dysregulated cellular proliferation and differentiation. We also found that Pcbp1 null mutant mice exhibit early embryonic lethality, indicating that Pcbp1 is indispensable for embryonic development. Interestingly, hypomorphic Pcbp1 mutant mice displayed defects in muscle growth due to defects in the proliferation and differentiation of myoblasts and muscle satellite cells, in addition to a slow to fast myofibril switch. Moreover, Pcbp1 modulated the processing of muscle-enriched miR-1, miR-133, and miR-206 by physically interacting with argonaute 2 (AGO2) and other miRNA pathway components. Our study, therefore, uncovers the important function of Pcbp1 in skeletal muscle and the microRNA pathway, signifying its potential as a therapeutic target for muscle disease.
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Affiliation(s)
- Ramón A Espinoza-Lewis
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Qiumei Yang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and.,Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 6111130, China
| | - Jianming Liu
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Zhan-Peng Huang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Xiaoyun Hu
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Daiwen Chen
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, Sichuan 6111130, China
| | - Da-Zhi Wang
- From the Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115 and
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42
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Ryu MS, Zhang D, Protchenko O, Shakoury-Elizeh M, Philpott CC. PCBP1 and NCOA4 regulate erythroid iron storage and heme biosynthesis. J Clin Invest 2017; 127:1786-1797. [PMID: 28375153 DOI: 10.1172/jci90519] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 02/02/2017] [Indexed: 01/03/2023] Open
Abstract
Developing erythrocytes take up exceptionally large amounts of iron, which must be transferred to mitochondria for incorporation into heme. This massive iron flux must be precisely controlled to permit the coordinated synthesis of heme and hemoglobin while avoiding the toxic effects of chemically reactive iron. In cultured animal cells, iron chaperones poly rC-binding protein 1 (PCBP1) and PCBP2 deliver iron to ferritin, the sole cytosolic iron storage protein, and nuclear receptor coactivator 4 (NCOA4) mediates the autophagic turnover of ferritin. The roles of PCBP, ferritin, and NCOA4 in erythroid development remain unclear. Here, we show that PCBP1, NCOA4, and ferritin are critical for murine red cell development. Using a cultured cell model of erythroid differentiation, depletion of PCBP1 or NCOA4 impaired iron trafficking through ferritin, which resulted in reduced heme synthesis, reduced hemoglobin formation, and perturbation of erythroid regulatory systems. Mice lacking Pcbp1 exhibited microcytic anemia and activation of compensatory erythropoiesis via the regulators erythropoietin and erythroferrone. Ex vivo differentiation of erythroid precursors from Pcbp1-deficient mice confirmed defects in ferritin iron flux and heme synthesis. These studies demonstrate the importance of ferritin for the vectorial transfer of imported iron to mitochondria in developing red cells and of PCBP1 and NCOA4 in mediating iron flux through ferritin.
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43
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Zhu T, Qiao L, Wang Q, Mi R, Chen J, Lu Y, Gu J, Zheng Q. T-box family of transcription factor-TBX5, insights in development and disease. Am J Transl Res 2017; 9:442-453. [PMID: 28337273 PMCID: PMC5340680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 02/03/2017] [Indexed: 06/06/2023]
Abstract
The T-box gene family refers to a group of transcription factors that share a highly conserved, sequence-specific DNA-binding domain (T-box) containing around 180-amino acids. According to HUGO gene nomenclature committee (HGNC), there are 18 T-box family members. These T-box genes have been implicated essential roles during embryogenesis and cardiac development, given their specific expression pattern in developing mammalian heart for several T-box genes, including TBX5. TBX5 is consisted of three transcriptional variants which cover 9 exons and encode two distinct isoforms that differ in N-terminus. TBX5 is probably the most frequently studied T-box gene over the past decade due to the typical cardiac defects observed in Holt-Oram syndrome (HOS), which is caused by TBX5 mutation. Most of the mutations are within exons 3-7 where locate sequence coding for the T-box domain. Notably, a variety of cardiac defects, as well as abnormalities in limb and other organs have been seen in HOS syndrome with different kinds of TBX5 mutations, suggesting a heterogeneous disease mechanism. We have performed a meta-analysis of TBX5 and found a significant correlation between its single nucleotide polymorphism (SNP) rs3825214 (A to G), and risk of atrial fibrillation and its subtypes, supporting TBX5 as a master transcription factor for cardiac development. In addition, bioinformatics analysis of this SNP identified several TFs that may be affected for their binding affinity with TBX5. Identification and characterization of more TBX5 mutations and SNPs hold promise for therapeutic strategy targeting TBX5 associated developmental abnormalities and diseases.
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Affiliation(s)
- Ting Zhu
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Longwei Qiao
- The Center for Reproduction and Genetics, Suzhou Hospital Affiliated to Nanjing Medical UniversitySuzhou, Jiangsu 215008, China
| | - Qian Wang
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Rui Mi
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Jinnan Chen
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Yaojuan Lu
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Junxia Gu
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
| | - Qiping Zheng
- Department of Hematological Laboratory Science, Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu UniversityZhenjiang 212013, Jiangsu, China
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44
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Poly(rC)-Binding Protein 2 Regulates Hippo Signaling To Control Growth in Breast Epithelial Cells. Mol Cell Biol 2016; 36:2121-31. [PMID: 27215387 DOI: 10.1128/mcb.00104-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/15/2016] [Indexed: 01/09/2023] Open
Abstract
Poly(rC)-binding proteins (PCBPs) are multifunctional adapters that mediate interactions between nucleic acids, iron cofactors, and other proteins, affecting the fates and activities of the components of these interactions. Here, we show that PCBP2 forms a complex with the Hippo pathway components Salvador (Sav1), Mst1, Mst2, and Lats1 in human cells and mouse tissues. Hippo is a kinase cascade that functions to phosphorylate and inactivate the transcriptional coactivators YAP and TAZ, which control cell growth and proliferation. PCBP2 specifically interacts with the scaffold protein Sav1 and prevents proteolytic cleavage of the Mst1 kinase, resulting in increased signaling through Hippo and suppressed activity of YAP and TAZ. Human breast epithelial cells lacking PCBP2 exhibit impaired proteasomal degradation of TAZ. They accumulate TAZ in both the nucleus and the cytosol, increase expression of YAP and TAZ connective tissue growth factor (CTGF) and Cyr61 target genes, and exhibit anchorage-independent growth. Thus, PCBP2 can function as a component of the Hippo complex, enhancing signaling, suppressing activity of YAP and TAZ, and altering the growth characteristics of cells.
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45
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Yanatori I, Richardson DR, Imada K, Kishi F. Iron Export through the Transporter Ferroportin 1 Is Modulated by the Iron Chaperone PCBP2. J Biol Chem 2016; 291:17303-18. [PMID: 27302059 DOI: 10.1074/jbc.m116.721936] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Indexed: 12/15/2022] Open
Abstract
Ferroportin 1 (FPN1) is an iron export protein found in mammals. FPN1 is important for the export of iron across the basolateral membrane of absorptive enterocytes and across the plasma membrane of macrophages. The expression of FPN1 is regulated by hepcidin, which binds to FPN1 and then induces its degradation. Previously, we demonstrated that divalent metal transporter 1 (DMT1) interacts with the intracellular iron chaperone protein poly(rC)-binding protein 2 (PCBP2). Subsequently, PCBP2 receives iron from DMT1 and then disengages from the transporter. In this study, we investigated the function of PCBP2 in iron export. Mammalian genomes encode four PCBPs (i.e. PCBP1-4). Here, for the first time, we demonstrated using both yeast and mammalian cells that PCBP2, but not PCBP1, PCBP3, or PCBP4, binds with FPN1. Importantly, iron-loaded, but not iron-depleted, PCBP2 interacts with FPN1. The PCBP2-binding domain of FPN1 was identified in its C-terminal cytoplasmic region. The silencing of PCBP2 expression suppressed FPN1-dependent iron export from cells. These results suggest that FPN1 exports iron received from the iron chaperone PCBP2. Therefore, it was found that PCBP2 modulates cellular iron export, which is an important physiological process.
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Affiliation(s)
- Izumi Yanatori
- From the Department of Molecular Genetics, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan and
| | - Des R Richardson
- the Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kiyoshi Imada
- From the Department of Molecular Genetics, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan and
| | - Fumio Kishi
- From the Department of Molecular Genetics, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan and
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46
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Yabe-Wada T, Matsuba S, Takeda K, Sato T, Suyama M, Ohkawa Y, Takai T, Shi H, Philpott CC, Nakamura A. TLR signals posttranscriptionally regulate the cytokine trafficking mediator sortilin. Sci Rep 2016; 6:26566. [PMID: 27220277 PMCID: PMC4879639 DOI: 10.1038/srep26566] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/04/2016] [Indexed: 01/14/2023] Open
Abstract
Regulating the transcription, translation and secretion of cytokines is crucial for controlling the appropriate balance of inflammation. Here we report that the sorting receptor sortilin plays a key role in cytokine production. We observed interactions of sortilin with multiple cytokines including IFN-α, and sortilin depletion in plasmacytoid dendritic cells (pDCs) led to a reduction of IFN-α secretion, suggesting a pivotal role of sortilin in the exocytic trafficking of IFN-α in pDCs. Moreover, sortilin mRNA was degraded posttranscriptionally upon stimulation with various TLR ligands. Poly-rC-binding protein 1 (PCBP1) recognized the C-rich element (CRE) in the 3′ UTR of sortilin mRNA, and depletion of PCBP1 enhanced the degradation of sortilin transcripts, suggesting that PCBP1 can act as a trans-acting factor to stabilize sortilin transcripts. The nucleotide-binding ability of PCBP1 was impaired by zinc ions and alterations of intracellular zinc affect sortilin expression. PCBP1 may therefore control the stability of sortilin transcripts by sensing intracellular zinc levels. Collectively, our findings provide insights into the posttranslational regulation of cytokine production through the posttranscriptional control of sortilin expression by TLR signals.
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Affiliation(s)
- Toshiki Yabe-Wada
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Ishikawa, 920-0293, JAPAN.,Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shintaro Matsuba
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Ishikawa, 920-0293, JAPAN
| | - Kazuya Takeda
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Ishikawa, 920-0293, JAPAN
| | - Tetsuya Sato
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Mikita Suyama
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Yasuyuki Ohkawa
- Department of Advanced Medical Initiatives, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan
| | - Toshiyuki Takai
- Department of Experimental Immunology, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo, Sendai 980-8575, Japan
| | - Haifeng Shi
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Caroline C Philpott
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Akira Nakamura
- Department of Immunology, Kanazawa Medical University, Kahoku Uchinada, Ishikawa, 920-0293, JAPAN
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47
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Ji X, Park JW, Bahrami-Samani E, Lin L, Duncan-Lewis C, Pherribo G, Xing Y, Liebhaber SA. αCP binding to a cytosine-rich subset of polypyrimidine tracts drives a novel pathway of cassette exon splicing in the mammalian transcriptome. Nucleic Acids Res 2016; 44:2283-97. [PMID: 26896798 PMCID: PMC4797308 DOI: 10.1093/nar/gkw088] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
Alternative splicing (AS) is a robust generator of mammalian transcriptome complexity. Splice site specification is controlled by interactions of cis-acting determinants on a transcript with specific RNA binding proteins. These interactions are frequently localized to the intronic U-rich polypyrimidine tracts (PPT) located 5′ to the majority of splice acceptor junctions. αCPs (also referred to as polyC-binding proteins (PCBPs) and hnRNPEs) comprise a subset of KH-domain proteins with high affinity and specificity for C-rich polypyrimidine motifs. Here, we demonstrate that αCPs promote the splicing of a defined subset of cassette exons via binding to a C-rich subset of polypyrimidine tracts located 5′ to the αCP-enhanced exonic segments. This enhancement of splice acceptor activity is linked to interactions of αCPs with the U2 snRNP complex and may be mediated by cooperative interactions with the canonical polypyrimidine tract binding protein, U2AF65. Analysis of αCP-targeted exons predicts a substantial impact on fundamental cell functions. These findings lead us to conclude that the αCPs play a direct and global role in modulating the splicing activity and inclusion of an array of cassette exons, thus driving a novel pathway of splice site regulation within the mammalian transcriptome.
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Affiliation(s)
- Xinjun Ji
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Juw Won Park
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA Department of Computer Engineering and Computer Science, University of Louisville, Louisville, KY 40292, USA KBRIN Bioinformatics Core, University of Louisville, Louisville, KY 40202, USA
| | - Emad Bahrami-Samani
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lan Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christopher Duncan-Lewis
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gordon Pherribo
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi Xing
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephen A Liebhaber
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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