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Huang S, Zhang J, He P, Cui X, Hou Y, Su W, Li F. Radiation-induced upregulation of FGL1 promotes esophageal squamous cell carcinoma metastasis via IMPDH1. BMC Cancer 2024; 24:557. [PMID: 38702629 PMCID: PMC11067193 DOI: 10.1186/s12885-024-12313-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND While radiation therapy remains pivotal in esophageal squamous cell carcinoma (ESCC) treatment, the perplexing phenomenon of post-radiation metastasis presents a formidable clinical challenge. This study investigates the role of fibrinogen-like protein 1 (FGL1) in driving ESCC metastasis following radiation exposure. METHODS FGL1 expression in post-radiation ESCC cells was meticulously examined using qRT-PCR, western blotting, and immunofluorescence. The impact of FGL1 on ESCC cell invasion and migration was assessed through Transwell and wound healing assays. In vivo, the metastatic potential of ESCC in response to FGL1 was scrutinized using nude mice models. Comprehensive RNA sequencing and functional experiments elucidated the intricate mechanism associated with FGL1. RESULTS Radiation induced upregulation of FGL1 in ESCC cells through FOXO4, intensifying ESCC cell invasion and migration. Targeted knockdown of FGL1 effectively alleviated these characteristics both in vitro and in vivo. FGL1 depletion concurrently suppressed IMPDH1 expression. Rescue experiments underscored that IMPDH1 knockdown robustly reversed the pro-invasive effects induced by FGL1 in ESCC cells. ESCC tissues exhibited heightened IMPDH1 mRNA levels, demonstrating a correlation with patient survival. CONCLUSIONS Radiation-induced upregulation of FGL1 propels ESCC metastasis through IMPDH1, proposing a potential therapeutic target to mitigate post-radiotherapy metastasis in ESCC patients.
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Affiliation(s)
- Shan Huang
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China.
| | - Jiayi Zhang
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Pu He
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Xinyue Cui
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Yuzhu Hou
- Department of Pathogenic Microbiology and Immunology, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, ShaanXi, China
| | - Wanghui Su
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
| | - Fang Li
- Department of Radiation Oncology, Second Affiliated Hospital, Xi'an Jiaotong University, No.157, Xi Wu Road, Xi'an, 710004, ShaanXi, China
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Wang J, Wang Y, Jiang Y, Li S, Jia X, Xiao X, Sun W, Wang P, Zhang Q. Datasets-Based IMPDH1 Revisited: Heterozygous Missense Variants for Dominant Retinitis Pigmentosa While Truncation Variants Are Likely Non-Pathogenic. Curr Eye Res 2024:1-9. [PMID: 38604988 DOI: 10.1080/02713683.2024.2336158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
PURPOSE Heterozygous variants of IMPDH1 are associated with autosomal dominant retinitis pigmentosa (adRP). The current study aims to investigate the characteristics of the adRP-associated variants. METHODS IMPDH1 variants from our exome sequencing dataset were retrieved and systemically evaluated through multiple online prediction tools, comparative genomics (in-house dataset, HGMD, and gnomAD), and phenotypic association. Potential pathogenic variants (PPVs) were further confirmed by Sanger sequencing and segregation analysis. RESULTS In total, seven heterozygous PPVs (six missenses and one inframe) were identified in 10 families with RP, in which six of the seven might be classified as pathogenic or likely pathogenic while one others as variants of uncertain significance. IMPDH1 variants contributed to 0.7% (10/1519) of RP families in our cohort, ranking the top four genes implicated in adRP. These adRP-associated variants were located in exons 8-10, a region within or downstream of the CBS domain. All these variants were predicted to be damaged by at least three of the six online prediction tools. Two truncation variants were considered non-pathogenic. Hitherto, 41 heterozygous variants of IMPDH1 were detected in 110 families in published literature, including 33 missenses, two inframes, and six truncations (including a synonymous variant affecting splicing). Of the 35 missense and inframe variants, most were clustered in exons 8-10 (77.1%, 27/35), including 18 (51.4%, 18/35) in exon 10 accounting for 70.9% (78/110) of the families. However, truncation variants were enriched in the general population with a pLI value of 0 (tolerated), and the reported variants in patients with RP did not cluster in specific region. CONCLUSIONS Our data together with comprehensive analysis of existing datasets suggest that causative variants of IMPDH1 are usually missense and mostly clustered in exons 8-10. Conversely, most missense variants outside this region and truncation variants should be interpreted with great care in clinical gene test.
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Affiliation(s)
- Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Department of Ophthalmology, The Central Hospital of Enshi Tujia and Miao Autonomous Prefecture, Enshi, Hubei, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guang-dong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Sakti DH, Cornish EE, Nash BM, Jamieson RV, Grigg JR. IMPDH1-associated autosomal dominant retinitis pigmentosa: natural history of novel variant Lys314Gln and a comprehensive literature search. Ophthalmic Genet 2023; 44:437-455. [PMID: 37259572 DOI: 10.1080/13816810.2023.2215310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/11/2023] [Accepted: 05/14/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Inosine monophosphate dehydrogenase (IMPDH) is a key regulatory enzyme in the de novo synthesis of the purine base guanine. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) are causative for RP10 autosomal dominant retinitis pigmentosa (adRP). This study reports a novel variant in a family with IMPDH1-associated retinopathy. We also performed a comprehensive review of all reported IMPDH1 disease causing variants with their associated phenotype. MATERIALS AND METHODS Multimodal imaging and functional studies documented the phenotype including best-corrected visual acuity (BCVA), fundus photograph, fundus autofluorescence (FAF), full field electroretinogram (ffERG), optical coherence tomography (OCT) and visual field (VF) data were collected. A literature search was performed in the PubMed and LOVD repositories. RESULTS We report 3 cases from a 2-generation family with a novel heterozygous likely pathogenic variant p. (Lys314Gln) (exon 10). The ophthalmic phenotype showed diffuse outer retinal atrophy with mild pigmentary changes with sparse pigmentary changes. FAF showed early macular involvement with macular hyperautofluorescence (hyperAF) surrounded by hypoAF. Foveal ellipsoid zone island can be found in the youngest patient but not in the older ones. The literature review identified a further 56 heterozygous, 1 compound heterozygous, and 2 homozygous variant. The heterozygous group included 43 missense, 3 in-frame, 1 nonsense, 2 frameshift, 1 synonymous, and 6 intronic variants. Exon 10 was noted as a hotspot harboring 18 variants. CONCLUSIONS We report a novel IMPDH1 variant. IMPDH1-associated retinopathy presents most frequently in the first decade of life with early macular involvement.
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Affiliation(s)
- Dhimas H Sakti
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Department of Ophthalmology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Elisa E Cornish
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Benjamin M Nash
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children's Hospitals Network, Sydney, New South Wales, Australia
| | - Robyn V Jamieson
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - John R Grigg
- Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
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Keppeke GD, Chang CC, Zhang Z, Liu JL. Effect on cell survival and cytoophidium assembly of the adRP-10-related IMPDH1 missense mutation Asp226Asn. Front Cell Dev Biol 2023; 11:1234592. [PMID: 37731818 PMCID: PMC10507268 DOI: 10.3389/fcell.2023.1234592] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 08/17/2023] [Indexed: 09/22/2023] Open
Abstract
Introduction: Inosine monophosphate dehydrogenase 1 (IMPDH1) is a critical enzyme in the retina, essential for the correct functioning of photoreceptor cells. Mutations in IMPDH1 have been linked to autosomal dominant retinitis pigmentosa subtype 10 (adRP-10), a genetic eye disorder. Some of these mutations such as the Asp226Asn (D226N) lead to the assembly of large filamentous structures termed cytoophidia. D226N also gives IMPDH1 resistance to feedback inhibition by GDP/GTP. This study aims to emulate the adRP-10 condition with a long-term expression of IMPDH1-D226N in vitro and explore cytoophidium assembly and cell survival. We also assessed whether the introduction of an additional mutation (Y12C) to disrupt the cytoophidium has an attenuating effect on the toxicity caused by the D226N mutation. Results: Expression of IMPDH1-D226N in HEp-2 cells resulted in cytoophidium assembly in ∼70% of the cells, but the presence of the Y12C mutation disrupted the filaments. Long-term cell survival was significantly affected by the presence of the D226N mutation, with a decrease of ∼40% in the cells expressing IMPDH1-D226N when compared to IMPDH1-WT; however, survival was significantly recovered in IMPDH1-Y12C/D226N, with only a ∼10% decrease when compared to IMPDH1-WT. On the other hand, the IMPDH1 expression level in the D226N-positive cells was <30% of that of the IMPDH1-WT-positive cells and only slightly higher in the Y12C/D226N, suggesting that although cell survival in Y12C/D226N was recovered, higher expression levels of the mutated IMPDH1 were not tolerated by the cells in the long term. Conclusion: The IMPDH1-D226N effect on photoreceptor cell survival may be the result of a sum of problems: nucleotide unbalance plus a toxic long-life cytoophidium, supported by the observation that by introducing Y12C in IMPDH1 the cytoophidium was disrupted and cell survival significantly recovered, but not the sensibility to GDP/GTP regulation since higher expression levels of IMPDH1-D226N were not tolerated.
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Affiliation(s)
- Gerson Dierley Keppeke
- Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Sao Paulo, Brazil
| | - Chia-Chun Chang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Ziheng Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ji-Long Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Zhang Q, Cui K, Yang X, He Q, Yu J, Yang L, Yao G, Guo W, Luo Z, Liu Y, Chen Y, He Z, Lan P. c-Myc- IMPDH1/2 axis promotes tumourigenesis by regulating GTP metabolic reprogramming. Clin Transl Med 2023; 13:e1164. [PMID: 36629054 PMCID: PMC9832425 DOI: 10.1002/ctm2.1164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Metabolic reprogramming is a hallmark of cancer. Metabolic rate-limiting enzymes and oncogenic c-Myc (Myc) play critical roles in metabolic reprogramming to affect tumourigenesis. However, a systematic assessment of metabolic rate-limiting enzymes and their relationship with Myc in human cancers is lacking. METHODS Multiple Pan-cancer datasets were used to develop the transcriptome, genomic alterations, clinical outcomes and Myc correlation landscapes of 168 metabolic rate-limiting enzymes across 20 cancers. Real-time quantitative PCR and immunoblotting were, respectively, used to examine the mRNA and protein of inosine monophosphate dehydrogenase 1 (IMPDH1) in human colorectal cancer (CRC), azoxymethane/dextran sulphate sodium-induced mouse CRC and spontaneous intestinal tumours from APCMin/+ mice. Clone formation, CCK-8 and subcutaneous xenograft model were applied to investigate the possible mechanisms connecting IMPDH1 to CRC growth. Co-immunoprecipitation and protein half-life assay were used to explore the mechanisms underlying the regulation of IMPDH1. RESULTS We explored the global expression patterns, dysregulation profiles, genomic alterations and clinical relevance of 168 metabolic rate-limiting enzymes across human cancers. Importantly, a series of enzymes were associated with Myc, especially top three upregulated enzymes (TK1, RRM2 and IMPDH1) were positively correlated with Myc in multiple cancers. As a proof-of-concept exemplification, we demonstrated that IMPDH1, a rate-limiting enzyme in GTP biosynthesis, is highly upregulated in CRC and promotes CRC growth in vitro and in vivo. Mechanistically, IMPDH2 stabilizes IMPDH1 by decreasing the polyubiquitination levels of IMPDH1, and Myc promotes the de novo GTP biosynthesis by the transcriptional activation of IMPDH1/2. Finally, we confirmed that the Myc-IMPDH1/2 axis is dysregulated across human cancers. CONCLUSIONS Our study highlights the essential roles of metabolic rate-limiting enzymes in tumourigenesis and their crosstalk with Myc, and the Myc-IMPDH1/2 axis promotes tumourigenesis by altering GTP metabolic reprogramming. Our results propose the inhibition of IMPDH1 as a viable option for cancer treatment.
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Affiliation(s)
- Qiang Zhang
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
| | - Kaisa Cui
- Wuxi Cancer InstituteAffiliated Hospital of Jiangnan UniversityWuxiJiangsuChina
| | - Xiaoya Yang
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
| | - Qilang He
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
| | - Jing Yu
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangdong Institute of GastroenterologyGuangzhouGuangdongChina
| | - Li Yang
- Zhumadian Central HospitalHuanghuai UniversityZhumadianHenanChina
| | - Gang Yao
- The People's Hospital of Zhengyang CountyZhumadianHenanChina
| | - Weiwei Guo
- The People's Hospital of Zhengyang CountyZhumadianHenanChina
| | - Zhanhao Luo
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangdong Institute of GastroenterologyGuangzhouGuangdongChina
| | - Yugeng Liu
- Center for Synthetic MicrobiomeInstitute of Synthetic BiologyShenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdongChina
| | - Yuan Chen
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
| | - Zhen He
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangdong Institute of GastroenterologyGuangzhouGuangdongChina
| | - Ping Lan
- The Sixth Affiliated HospitalSchool of MedicineSun Yat‐sen UniversityGuangzhouGuangdongChina
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangdong Institute of GastroenterologyGuangzhouGuangdongChina
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Liu C, Zhang W, Zhou X, Liu L. IMPDH1, a prognostic biomarker and immunotherapy target that correlates with tumor immune microenvironment in pan-cancer and hepatocellular carcinoma. Front Immunol 2022; 13:983490. [PMID: 36618420 PMCID: PMC9813230 DOI: 10.3389/fimmu.2022.983490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Backgrounds IMPDH1, a rate-limiting enzyme in de novos synthesis of guanine nucleotides, plays an essential role in the growth and progression of certain tumors. However, there is still a lack of study on IMPDH1 evaluating its role in the tumor immune microenvironment, the potential mechanisms, and its potential as a promising tumor therapeutic target. Methods The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Genotype-Tissue Expression (GTEx), TIMER2.0, KM-Plotter, University of Alabama at Birmingham Cancer data analysis Portal (UALCAN), cbioportal, The Human Protein Atlas (HPA), and Gene Expression Profiling Interactive Analysis 2 (GEPIA2) were used to perform the systematic analysis of IMPDH1, including mRNA expression, protein expression, prognostic value, Enrichment analysis, DNA methylation, immune cell infiltration in pan-cancer, Then, we conducted qRT-PCR and immunohistochemistry to analyze the expression level of IMPDH1 in cancer tissues and non-cancer tissues of patients with primary hepatocellular carcinoma (HCC), and performed the same verification at cellular level. Results We discovered that IMPDH1 was highly expressed in a variety of tumors and was associated with poor prognosis. IMPDH1 not only had the potential as a tumor prognostic marker and therapeutic target, but also was closely related to immune cells, immune checkpoints and immune-related genes and pathways in the tumor immune microenvironment (TIME). Meanwhile, IMPDH1 expression influenced the efficacy and prognosis of tumor patients treated with immune checkpoint inhibitors. Conclusions IMPDH1 may be as a potential combined target of immunotherapy.
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Affiliation(s)
- Chengdong Liu
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Wanli Zhang
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiaohan Zhou
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Li Liu
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China,*Correspondence: Li Liu,
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Zhao JZ, Wang W, Liu T, Zhang L, Lin DZ, Yao JY, Peng X, Jin G, Ma TT, Gao JB, Huang F, Nie J, Lv Q. MYBL2 regulates de novo purine synthesis by transcriptionally activating IMPDH1 in hepatocellular carcinoma cells. BMC Cancer 2022; 22:1290. [PMID: 36494680 PMCID: PMC9733023 DOI: 10.1186/s12885-022-10354-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Metabolic reprogramming is a hallmark of cancer, alteration of nucleotide metabolism of hepatocellular carcinoma (HCC) is not well-understood. MYBL2 regulates cell cycle progression and hepatocarcinogenesis, its role in metabolic regulation remains elusive. PATIENTS AND METHODS Copy number, mRNA and protein level of MYBL2 and IMPDH1 were analyzed in HCC, and correlated with patient survival. Chromatin Immunoprecipitation sequencing (Chip-seq) and Chromatin Immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR) were used to explore the relationship between MYBL2 and IMPDH1. Metabolomics were used to analyze how MYBL2 affected purine metabolism. The regulating effect of MYBL2 in HCC was further validated in vivo using xenograft models. RESULTS The Results showed that copy-number alterations of MYBL2 occur in about 10% of human HCC. Expression of MYBL2, IMPDH1, or combination of both were significantly upregulated and associated with poor prognosis in HCC. Correlation, ChIP-seq and ChIP-qPCR analysis revealed that MYBL2 activates transcription of IMPDH1, while knock-out of MYBL2 retarded IMPDH1 expression and inhibited proliferation of HCC cells. Metabolomic analysis post knocking-out of MYBL2 demonstrated that it was essential in de novo purine synthesis, especially guanine nucleotides. In vivo analysis using xenograft tumors also revealed MYBL2 regulated purine synthesis by regulating IMPDH1, and thus, influencing tumor progression. CONCLUSION MYBL2 is a key regulator of purine synthesis and promotes HCC progression by transcriptionally activating IMPDH1, it could be a potential candidate for targeted therapy for HCC.
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Affiliation(s)
- Jun-Zhang Zhao
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China ,grid.488525.6Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China
| | - Wei Wang
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China ,grid.488525.6Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China
| | - Tao Liu
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China ,grid.488525.6Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China
| | - Lei Zhang
- grid.488525.6Department of Pancreatic-hepatobiliary Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China
| | - De-Zheng Lin
- grid.484195.5Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangdong Institute of Gastroenterology, 510655 Guangzhou, China ,grid.488525.6Department of Endoscopic Surgery, The Sixth Affiliated Hospital, Sun Yat-Sen University, 510655 Guangzhou, China
| | - Jia-Yin Yao
- grid.488525.6Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China ,grid.484195.5Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangdong Institute of Gastroenterology, 510655 Guangzhou, China
| | - Xiang Peng
- grid.488525.6Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, 510655 Guangzhou, China ,grid.484195.5Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Supported by National Key Clinical Discipline, Guangdong Institute of Gastroenterology, 510655 Guangzhou, China
| | - Gang Jin
- grid.33199.310000 0004 0368 7223Department of Thoracic Surgery, Union Jiangnan Hospital, Huazhong University of Science and Technology, Hubei 43022 Wuhan, China
| | - Tian-Tian Ma
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
| | - Jin-Bo Gao
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
| | - Fang Huang
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China ,grid.33199.310000 0004 0368 7223Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei 43022 Wuhan, China
| | - Jun Nie
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China ,grid.33199.310000 0004 0368 7223Department of Thoracic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei 43022 Wuhan, China
| | - Qing Lv
- grid.33199.310000 0004 0368 7223Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
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Cheng L, Yao P, Weng B, Yang M, Wang Q. Meta-analysis of the associations of IMPDH and UGT1A9 polymorphisms with rejection in kidney transplant recipients taking mycophenolic acid. Eur J Clin Pharmacol 2022; 78:1227-1238. [PMID: 35524809 DOI: 10.1007/s00228-022-03311-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/05/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the associations of IMPDH and UGT1A9 polymorphisms with rejection in kidney transplant recipients taking mycophenolic acid (MPA). METHODS PubMed, Web of Science, Embase, Cochrane Library, Wanfang Data, and the China Academic Journal Network Publishing Database were systematically searched for studies investigating the associations of IMPDH1, IMPDH2, and UGT1A9 polymorphisms with rejection in kidney transplant recipients taking MPA. Associations were evaluated by pooled odds ratios (ORs) and effect sizes (ESs) with 95% confidence intervals (CIs). RESULTS Twelve studies were included in the analysis, including a total of 2342 kidney transplant recipients. The results showed that compared with the TC + CC variant genotypes, the TT genotype of IMPDH2 3757 T > C was significantly associated with a higher risk of rejection (ES = 1.60, 95% CI = 1.07-2.40, P = 0.021), while there was no significant association of the IMPDH2 3757 T > C polymorphism with acute rejection within 1 year in kidney transplant recipients (OR = 1.49, 95% CI = 0.79-2.80, P = 0.217; ES = 1.44, 95% CI = 0.88-2.36, P = 0.142). The GG genotypes of IMPDH1 125G > A and IMPDH1 106G > A were significantly associated with a higher risk of rejection (ES = 1.91, 95% CI = 1.11-3.28, P = 0.019) and acute rejection within 1 year (ES = 2.12, 95% CI = 1.45-3.10, P < 0.001) than the variant genotypes GA + AA. The TT genotype of UGT1A9 275 T > A showed a decreased risk of rejection compared with the variant genotypes TA + AA (ES = 0.44, 95% CI = 0.23-0.84, P = 0.013). CONCLUSIONS IMPDH1, IMPDH2, and UGT1A9 polymorphisms were associated with rejection in kidney transplant recipients, and the genetic backgrounds of patients should be considered when using MPA.
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Affiliation(s)
- Lin Cheng
- Department of Pharmacy, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Pu Yao
- Department of Pharmacy, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Bangbi Weng
- Department of Pharmacy, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, 400038, China
| | - Ming Yang
- Department of Pharmacy, The Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, China.
| | - Qian Wang
- Department of Pharmacy, The First Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, 400038, China.
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9
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Andashti B, Yazdanparast R, Motahar M, Barzegari E, Galehdari H. Terminal Peptide Extensions Augment the Retinal IMPDH1 Catalytic Activity and Attenuate the ATP-induced Fibrillation Events. Cell Biochem Biophys 2021; 79:221-9. [PMID: 33733369 DOI: 10.1007/s12013-021-00973-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
Defects in inosine monophosphate dehydrogenase-1 (IMPDH1) lead to insufficient biosyntheses of purine nucleotides. In eyes, these defects are believed to cause retinitis pigmentosa (RP). Major retinal isoforms of IMPDH1 are structurally distinct from those in other tissues, by bearing terminal extensions. Using recombinant mouse IMPDH1 (mH1), we evaluated the kinetics and oligomerization states of the retinal isoforms. Moreover, we adopted molecular simulation tools to study the possible effect of terminal tails on the function of major enzyme isoforms with the aim to find structural evidence in favor of contradictory observations on retinal IMPDH1 function. Our findings indicated higher catalytic activity for the major mouse retinal isoform (mH1603) along with lower fibrillation capacity under the influence of ATP. However, higher mass oligomerization products were formed by the mH1 (603) isoform in the presence of the enzyme inhibitors such as GTP and/or MPA. Collectively, our findings demonstrate that the structural differences between the retinal isoforms have led to functional variations possibly to justify the retinal cells' requirements.
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10
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Bennett LD, Klein M, John FT, Radojevic B, Jones K, Birch DG. Disease Progression in Patients with Autosomal Dominant Retinitis Pigmentosa due to a Mutation in Inosine Monophosphate Dehydrogenase 1 ( IMPDH1). Transl Vis Sci Technol 2020; 9:14. [PMID: 32821486 PMCID: PMC7401855 DOI: 10.1167/tvst.9.5.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/10/2020] [Indexed: 02/06/2023] Open
Abstract
Purpose Mutations in the inosine monophosphate dehydrogenase 1 (IMPDH1) gene are a common cause of inherited retinal degeneration (IRD). Due to species- and tissue-dependent expression of IMPDH1, there are no appropriate models of human IMPDH1 disease. Therefore, a limited understanding remains of disease expression and rates of progression for IMPDH1-related IRD. Methods We evaluated semiautomated kinetic and chromatic static perimetry, spectral-domain optical coherence tomography (SD-OCT), and ultra-wide field fundus images with autofluorescence in a cohort of 12 patients (ages 11–58 at first visit). Ten patients had longitudinal data for which rates of progression were estimated. Results Visual acuities were relatively stable over time and the photoreceptors within the central retina remained intact. Perifoveal photoreceptor loss measured over a period of years coincided with visual fields, which were constricted and progressed over time in all patients. Rod sensitivity showed a similar pattern of defect to that of the kinetic perimetry and the autofluorescence ultra-wide field imaging. Full-field electroretinograms were severely reduced and the dark-adapted rod and mixed responses were extinguished at earlier visits than the light-adapted cone responses. Conclusions There was variability in disease severity at the first visit, but results show that the peripheral retina is more susceptible to the deleterious consequences of an IMPDH1 mutation. Given the pattern of degeneration and the alternatively spliced isoforms of IMPDH1, potential interventions may consider targeting the periphery early in disease, modulating transcript expression, and/or preserving central vision at late stages of the disease. Translational Relevance These results inform clinical prognosis and offer evidence strategies toward therapeutic intervention.
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Affiliation(s)
- Lea D Bennett
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Martin Klein
- Retina Foundation of the Southwest, Dallas, TX, USA
| | - Finny T John
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Bojana Radojevic
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Kaylie Jones
- Retina Foundation of the Southwest, Dallas, TX, USA
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, TX, USA.,Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
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11
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Plana-Bonamaisó A, López-Begines S, Fernández-Justel D, Junza A, Soler-Tapia A, Andilla J, Loza-Alvarez P, Rosa JL, Miralles E, Casals I, Yanes O, de la Villa P, Buey RM, Méndez A. Post-translational regulation of retinal IMPDH1 in vivo to adjust GTP synthesis to illumination conditions. eLife 2020; 9:56418. [PMID: 32254022 PMCID: PMC7176436 DOI: 10.7554/elife.56418] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023] Open
Abstract
We report the in vivo regulation of Inosine-5´-monophosphate dehydrogenase 1 (IMPDH1) in the retina. IMPDH1 catalyzes the rate-limiting step in the de novo synthesis of guanine nucleotides, impacting the cellular pools of GMP, GDP and GTP. Guanine nucleotide homeostasis is central to photoreceptor cells, where cGMP is the signal transducing molecule in the light response. Mutations in IMPDH1 lead to inherited blindness. We unveil a light-dependent phosphorylation of retinal IMPDH1 at Thr159/Ser160 in the Bateman domain that desensitizes the enzyme to allosteric inhibition by GDP/GTP. When exposed to bright light, living mice increase the rate of GTP and ATP synthesis in their retinas; concomitant with IMPDH1 aggregate formation at the outer segment layer. Inhibiting IMPDH activity in living mice delays rod mass recovery. We unveil a novel mechanism of regulation of IMPDH1 in vivo, important for understanding GTP homeostasis in the retina and the pathogenesis of adRP10 IMPDH1 mutations.
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Affiliation(s)
- Anna Plana-Bonamaisó
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut de Neurociències, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Santiago López-Begines
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - David Fernández-Justel
- Metabolic Engineering Group, Department of Microbiology and Genetics. University of Salamanca, Salamanca, Spain
| | - Alexandra Junza
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Ariadna Soler-Tapia
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Jordi Andilla
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Pablo Loza-Alvarez
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Spain
| | - Jose Luis Rosa
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
| | - Esther Miralles
- Centres Cientifics i Tecnològics (CCiTUB), University of Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - Isidre Casals
- Centres Cientifics i Tecnològics (CCiTUB), University of Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - Oscar Yanes
- CIBER of Diabetes and Associated Metabolic Diseases (CIBERDEM), Madrid, Spain.,Metabolomics Platform, IISPV, Department of Electronic Engineering, Universitat Rovira i Virgili, Tarragona, Spain
| | - Pedro de la Villa
- Physiology Unit, Dept of Systems Biology, School of Medicine, University of Alcalá, Madrid, Spain.,Visual Neurophysiology Group-IRYCIS, Madrid, Spain
| | - Ruben M Buey
- Metabolic Engineering Group, Department of Microbiology and Genetics. University of Salamanca, Salamanca, Spain
| | - Ana Méndez
- Department of Physiological Sciences, School of Medicine, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut de Neurociències, Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain.,Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Campus Universitari de Bellvitge, University of Barcelona, Barcelona, Spain
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12
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Ruan H, Song Z, Cao Q, Ni D, Xu T, Wang K, Bao L, Tong J, Xiao H, Xiao W, Cheng G, Xiong Z, Liang H, Liu D, Wang L, Olivier T, Jane BH, Yang H, Zhang X, Chen K. IMPDH1/YB-1 Positive Feedback Loop Assembles Cytoophidia and Represents a Therapeutic Target in Metastatic Tumors. Mol Ther 2020; 28:1299-1313. [PMID: 32209435 DOI: 10.1016/j.ymthe.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/20/2020] [Accepted: 03/05/2020] [Indexed: 01/28/2023] Open
Abstract
Recently, cytoophidium, a nonmembrane-bound intracellular polymeric structure, has been shown to exist in various organisms, including tumor tissues, but its function and mechanism have not yet been examined. Examination of cytoophidia-assembled gene inosine monophosphate dehydrogenase (IMPDH) and cytidine triphosphate synthetase (CTPS) mRNA levels showed that only IMPDH1 levels were significantly higher in the clear cell renal cell carcinoma (ccRCC). IMPDH1 was positively correlated with the metastasis-related gene Y-box binding protein 1 (YB-1) and served as an independent prognostic factor in ccRCC. Kaplan-Meier analysis indicated that patients with tumors that expressed high IMPDH1 levels had a shorter overall survival (OS) and disease-free survival (DFS). Furthermore, detection of cytoophidia by immunofluorescence staining in ccRCC tissues showed that IMPDH1-assembled cytoophidia are positively associated with tumor metastasis. Mechanistically, IMPDH1 and YB-1 formed an autoregulatory positive feedback loop: IMPDH1 maintained YB-1 protein stabilization; YB-1 induced IMPDH1 expression by binding to the IMPDH1 promoter motif. Functionally, IMPDH1-assembled cytoophidia physically interacted with YB-1 and translocated YB-1 into the cell nucleus, thus correlating with ccRCC metastasis. Our findings provide the first solid theoretical rationale for targeting the IMPDH1/YB-1 axis to improve metastatic renal cancer treatment.
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Affiliation(s)
- Hailong Ruan
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhengshuai Song
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qi Cao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Dong Ni
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Tianbo Xu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Keshan Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Lin Bao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Junwei Tong
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Haibing Xiao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Wen Xiao
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Gong Cheng
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhiyong Xiong
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Huageng Liang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Di Liu
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Liang Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Tredan Olivier
- Department of Oncology, Centre Leon Berard, 28 Prom. Léa et Napoléon Bullukian, 69008 Lyon, France
| | - Boyle Helen Jane
- Department of Oncology, Centre Leon Berard, 28 Prom. Léa et Napoléon Bullukian, 69008 Lyon, France
| | - Hongmei Yang
- Department of Pathogenic Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoping Zhang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Ke Chen
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China; Institute of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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13
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Andashti B, Yazdanparast R, Barzegari E, Galehdari H. The functional impact of the C/N-terminal extensions of the mouse retinal IMPDH1 isoforms: a kinetic evaluation. Mol Cell Biochem 2020; 465:155-64. [PMID: 31838626 DOI: 10.1007/s11010-019-03675-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/07/2019] [Indexed: 10/25/2022]
Abstract
Mutations in the retinal inosine monophosphate dehydrogenase1 (IMPDH1) gene is believed to be one cause of retinitis pigmentosa (RP). The main structural difference between the mutation-susceptible retinal isoforms with canonical one resides in the C- and N-terminal extensions. There are limited studies on the structure and function of terminal peptide extensions of the IMPDH1 retinal isoforms. Using recombinant murine IMPDH1 (mH1), we evaluated the kinetics of the retinal isoforms along with inhibition by some of the purine nucleotides. Molecular modeling tools were also applied to study the probable effect(s) of the terminal peptide tails on the function of the retinal isoforms. Molecular dynamic simulations indicated the possible impact of the end-terminal segments on the enzyme function through interactions with the enzyme's finger domain, affecting its critical pseudo barrel structure. The higher experimentally-determined Km and Ki values of the retinal mIMPDH1 (546) and mIMPDH1 (603) relative to that of the canonical isoform, mIMPDH1 (514), might clearly be due to these interactions. Furthermore and despite of the canonical isoform, the retinal isoforms of mH1 exhibited no NAD+ substrate inhibition. The resent data would certainly provide the ground for future evaluation of the physiological significance of these variations.
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