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Ge Y, Zadeh M, Sharma C, Lin YD, Soshnev AA, Mohamadzadeh M. Controlling functional homeostasis of ileal resident macrophages by vitamin B12 during steady state and Salmonella infection in mice. Mucosal Immunol 2024:S1933-0219(24)00091-6. [PMID: 39255854 DOI: 10.1016/j.mucimm.2024.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 08/13/2024] [Accepted: 08/30/2024] [Indexed: 09/12/2024]
Abstract
Dietary micronutrients, particularly vitamin B12 (VB12), profoundly influence the physiological maintenance and function of intestinal cells. However, it is still unclear whether VB12 modulates the transcriptional and metabolic programming of ileal macrophages (iMacs), thereby contributing to intestinal homeostasis. Using multiomic approaches, we demonstrated that VB12 primarily supports the cell cycle activity and mitochondrial metabolism of iMacs, resulting in increased cell frequency compared to VB12 deficiency. VB12 also retained the ability to promote maintenance and metabolic regulation of iMacs during intestinal infection with Salmonella Typhimurium (STm). On the contrary, depletion of iMacs by inhibiting CSF1R signaling significantly increased host susceptibility to STm and prevented VB12-mediated pathogen reduction. These results thus suggest that regulation of VB12-dependent iMacs critically controls STm expansion, which may be of new relevance to advance our understanding of this vitamin and to strategically formulate sustainable therapeutic nutritional regimens that improve human gut health.
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Affiliation(s)
- Yong Ge
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA.
| | - Mojgan Zadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Cheshta Sharma
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Yang-Ding Lin
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Alexey A Soshnev
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, TX, USA
| | - Mansour Mohamadzadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA; South Texas Veterans Health Care System (STVHCS), San Antonio, TX, USA.
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2
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Arcot A, Walker RE, Gallagher K, Klatt KC, Gernand AD. Maternal Vitamin B12 in Pregnancy and Placental Development. J Nutr Metab 2024; 2024:3439995. [PMID: 39148633 PMCID: PMC11326881 DOI: 10.1155/2024/3439995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/07/2024] [Accepted: 06/28/2024] [Indexed: 08/17/2024] Open
Abstract
Vitamin B12, or cobalamin, is an essential nutrient required for diverse physiological functions secondary to its role as a critical cofactor for two mammalian enzymes, methionine synthase and methylmalonyl-CoA mutase. While essential throughout all life stages, several pathways that require vitamin B12, including hematopoiesis, myelination, and DNA/histone methylation, are particularly critical during pregnancy and fetal development. This narrative review aims to describe vitamin B12 in pregnancy, with emphasis on the placenta's role in ensuring adequate nutrition of the fetus and impacts of vitamin B12 deficiency on placental development and function. Our literature search included preclinical model systems and human cohorts and interventions. Our review identified evidence of B12 deficiency resulting in impaired placental development, greater placental inflammation, and modulation of placental docosahexaenoic acid concentration, collectively suggestive of vitamin B12 deficiency as a determinant of both maternal and fetal health outcomes. Heterogeneity in study design complicated generalization of findings. Future studies should consider selecting a B12 marker that is relatively stable across pregnancy, such as holotranscobalamin, while accounting for important confounders such as maternal folate.
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Affiliation(s)
- Amrita Arcot
- Department of Nutritional Sciences The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Rachel E Walker
- Department of Nutritional Sciences The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kelly Gallagher
- Ross and Carol Nese College of Nursing The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kevin C Klatt
- Department of Nutritional Sciences and Toxicology University of California, Berkeley, California, USA
| | - Alison D Gernand
- Department of Nutritional Sciences The Pennsylvania State University, University Park, Pennsylvania, USA
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3
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Muralidharan J, Romould GG, Kashyap S, Pasanna R, Sivadas A, Sachdev HS, Kurpad AV, Devi S. Effect of calcium supplementation on reversing metformin-based inhibition of vitamin B 12 bioavailability in healthy adults using a [ 13C] cyanocobalamin tracer - A pilot study. Clin Nutr ESPEN 2024; 62:76-80. [PMID: 38901951 DOI: 10.1016/j.clnesp.2024.04.024] [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: 12/12/2023] [Revised: 04/14/2024] [Accepted: 04/29/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND & AIMS Metformin is a widely prescribed first line drug for the treatment of type 2 diabetes mellitus (DM). Studies have shown that the use of metformin is often associated with a decrease in vitamin B12 (B12) levels in patients with DM. Few studies have shown that this effect could be mitigated with calcium supplementation. In the present study, we quantified the effect of metformin, and metformin co-administered with calcium on B12 absorption using a novel stable isotope [13C] cyanocobalamin tracer. METHODS A pilot crossover study was conducted to estimate the bioavailability of B12 in healthy subjects, using [13C] cyanocobalamin as a tracer. In the study, [13C] cyanocobalamin was administered orally to the participants followed by hourly venous sampling to measure the concentration of the tracer and estimate bioavailability. This protocol was followed for three experiment days, each separated by a one month wash out period. As part of the study, all participants received the tracer alone for the control day (C), metformin 850 mg along with the tracer for the metformin day (M) and metformin 850 mg with calcium 500 mg and the tracer for the metformin calcium day (MC). RESULTS Seven participants completed all three experiment days. The mean B12 bioavailability (±SD, n = 7) was 42.6 ± 10.2% for the control day (C), 30.8 ± 15.3% for the metformin day (M) and 46.4 ± 8.6% for the metformin-calcium day (MC). Repeated measures ANOVA was done and the pairwise comparison showed a significant difference in the B12 bioavailability between control and metformin day (C vs M p = 0.010), and between the metformin and metformin with calcium day (M vs MC p = 0.003). CONCLUSION B12 bioavailability reduced significantly from baseline (C) when metformin (M) was administered and this reduction was reversed when calcium was co-administered (MC) in healthy participants. In patients using metformin, calcium supplementation as a strategy to prevent B12 deficiency needs to be further studied.
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Affiliation(s)
- Jananee Muralidharan
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Gunjit Glen Romould
- Medical Student, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Sindhu Kashyap
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Roshni Pasanna
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Ambily Sivadas
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Harshpal S Sachdev
- Department of Paediatrics, Sitaram Bhartia Institute of Science and Research, New Delhi, India
| | - Anura V Kurpad
- Department of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
| | - Sarita Devi
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India.
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Mucha P, Kus F, Cysewski D, Smolenski RT, Tomczyk M. Vitamin B 12 Metabolism: A Network of Multi-Protein Mediated Processes. Int J Mol Sci 2024; 25:8021. [PMID: 39125597 PMCID: PMC11311337 DOI: 10.3390/ijms25158021] [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: 06/03/2024] [Revised: 07/12/2024] [Accepted: 07/19/2024] [Indexed: 08/12/2024] Open
Abstract
The water-soluble vitamin, vitamin B12, also known as cobalamin, plays a crucial role in cellular metabolism, particularly in DNA synthesis, methylation, and mitochondrial functionality. Its deficiency can lead to hematological and neurological disorders; however, the manifestation of these clinical outcomes is relatively late. It leads to difficulties in the early diagnosis of vitamin B12 deficiency. A prolonged lack of vitamin B12 may have severe consequences including increased morbidity to neurological and cardiovascular diseases. Beyond inadequate dietary intake, vitamin B12 deficiency might be caused by insufficient bioavailability, blood transport disruptions, or impaired cellular uptake and metabolism. Despite nearly 70 years of knowledge since the isolation and characterization of this vitamin, there are still gaps in understanding its metabolic pathways. Thus, this review aims to compile current knowledge about the crucial proteins necessary to efficiently accumulate and process vitamin B12 in humans, presenting these systems as a multi-protein network. The epidemiological consequences, diagnosis, and treatment of vitamin B12 deficiency are also highlighted. We also discuss clinical warnings of vitamin B12 deficiency based on the ongoing test of specific moonlighting proteins engaged in vitamin B12 metabolic pathways.
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Affiliation(s)
- Patryk Mucha
- Department of Biochemistry, Medical University of Gdansk, 80-210 Gdansk, Poland; (P.M.); (F.K.); (R.T.S.)
| | - Filip Kus
- Department of Biochemistry, Medical University of Gdansk, 80-210 Gdansk, Poland; (P.M.); (F.K.); (R.T.S.)
- Laboratory of Protein Biochemistry, Intercollegiate Faculty of Biotechnology of University of Gdansk and Medical University of Gdansk, 80-307 Gdansk, Poland
| | - Dominik Cysewski
- Clinical Research Centre, Medical University of Bialystok, 15-276 Bialystok, Poland;
| | - Ryszard T. Smolenski
- Department of Biochemistry, Medical University of Gdansk, 80-210 Gdansk, Poland; (P.M.); (F.K.); (R.T.S.)
| | - Marta Tomczyk
- Department of Biochemistry, Medical University of Gdansk, 80-210 Gdansk, Poland; (P.M.); (F.K.); (R.T.S.)
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Cho H, Huh KM, Cho HJ, Kim B, Shim MS, Cho YY, Lee JY, Lee HS, Kwon YJ, Kang HC. Beyond nanoparticle-based oral drug delivery: transporter-mediated absorption and disease targeting. Biomater Sci 2024; 12:3045-3067. [PMID: 38712883 DOI: 10.1039/d4bm00313f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Various strategies at the microscale/nanoscale have been developed to improve oral absorption of therapeutics. Among them, gastrointestinal (GI)-transporter/receptor-mediated nanosized drug delivery systems (NDDSs) have drawn attention due to their many benefits, such as improved water solubility, improved chemical/physical stability, improved oral absorption, and improved targetability of their payloads. Their therapeutic potential in disease animal models (e.g., solid tumors, virus-infected lungs, metastasis, diabetes, and so on) has been investigated, and could be expanded to disease targeting after systemic/lymphatic circulation, although the detailed paths and mechanisms of endocytosis, endosomal escape, intracellular trafficking, and exocytosis through the epithelial cell lining in the GI tract are still unclear. Thus, this review summarizes and discusses potential GI transporters/receptors, their absorption and distribution, in vivo studies, and potential sequential targeting (e.g., oral absorption and disease targeting in organs/tissues).
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Affiliation(s)
- Hana Cho
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
| | - Kang Moo Huh
- Department of Polymer Science and Engineering & Materials Science and Engineering, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Hyun Ji Cho
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
| | - Bogeon Kim
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
| | - Min Suk Shim
- Division of Bioengineering, Incheon National University, Incheon 22012, Republic of Korea
| | - Yong-Yeon Cho
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
- Regulated Cell Death (RCD) Control Material Research Institute, The Catholic University of Korea, Bucheon, 14662, Republic of Korea
| | - Joo Young Lee
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
- Regulated Cell Death (RCD) Control Material Research Institute, The Catholic University of Korea, Bucheon, 14662, Republic of Korea
| | - Hye Suk Lee
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
- Regulated Cell Death (RCD) Control Material Research Institute, The Catholic University of Korea, Bucheon, 14662, Republic of Korea
| | - Young Jik Kwon
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - Han Chang Kang
- Department of Pharmacy, College of Pharmacy, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
- Regulated Cell Death (RCD) Control Material Research Institute, The Catholic University of Korea, Bucheon, 14662, Republic of Korea
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Ge Y, Yang C, Zadeh M, Sprague SM, Lin YD, Jain HS, Determann BF, Roth WH, Palavicini JP, Larochelle J, Candelario-Jalil E, Mohamadzadeh M. Functional regulation of microglia by vitamin B12 alleviates ischemic stroke-induced neuroinflammation in mice. iScience 2024; 27:109480. [PMID: 38715940 PMCID: PMC11075062 DOI: 10.1016/j.isci.2024.109480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/14/2023] [Accepted: 03/08/2024] [Indexed: 05/12/2024] Open
Abstract
Ischemic stroke is the second leading cause of death and disability worldwide, and efforts to prevent stroke, mitigate secondary neurological damage, and promote neurological recovery remain paramount. Recent findings highlight the critical importance of microbiome-related metabolites, including vitamin B12 (VB12), in alleviating toxic stroke-associated neuroinflammation. Here, we showed that VB12 tonically programmed genes supporting microglial cell division and activation and critically controlled cellular fatty acid metabolism in homeostasis. Intriguingly, VB12 promoted mitochondrial transcriptional and metabolic activities and significantly restricted stroke-associated gene alterations in microglia. Furthermore, VB12 differentially altered the functions of microglial subsets during the acute phase of ischemic stroke, resulting in reduced brain damage and improved neurological function. Pharmacological depletion of microglia before ischemic stroke abolished VB12-mediated neurological improvement. Thus, our preclinical studies highlight the relevance of VB12 in the functional programming of microglia to alleviate neuroinflammation, minimize ischemic injury, and improve host neurological recovery after ischemic stroke.
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Affiliation(s)
- Yong Ge
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Changjun Yang
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Mojgan Zadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Shane M. Sprague
- Department of Neurosurgery, University of Texas Health, San Antonio, TX, USA
| | - Yang-Ding Lin
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Heetanshi Sanjay Jain
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | | | - William H. Roth
- Department of Neurology, University of Chicago Medical Center, Chicago, IL, USA
| | - Juan Pablo Palavicini
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
| | - Jonathan Larochelle
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Eduardo Candelario-Jalil
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Mansour Mohamadzadeh
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Health, San Antonio, TX, USA
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Kent K, Nozawa K, Sutton C, Daniel F, Ikawa M, Garcia TX, Matzuk MM. CUB domains are not required for OVCH2 function in sperm maturation in the mouse epididymis. Andrology 2024; 12:682-697. [PMID: 37551853 PMCID: PMC10850435 DOI: 10.1111/andr.13508] [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: 05/31/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND Ovochymase 2 (Ovch2) is an epididymis-specific gene that is required for male fertility. While a multitude of reproductive tract-specific genes required for male fertility have been identified, OVCH2 is thus far the first protein required for male fertility that contains Complement C1r/C1s, Uegf, Bmp1 (CUB) domains located in tandem in the C-terminus of the protein. Identifying the functional significance of this unique domain has implications in better understanding fertility and infertility and as a potential contraceptive target. OBJECTIVE The goals of these studies were to understand the influence and requirement of OVCH2 CUB domains in the localization and functional requirement of OVCH2 in sperm maturation and function. MATERIALS AND METHODS To this end, we performed in vivo localization analysis of OVCH2 and reproductive phenotype analysis of mice containing C-terminal FLAG tag on OVCH2, with either the entire protein intact, or CUB2 or both CUB1 and CUB2 genetically ablated. All mice were generated through the CRISPR/Cas9 gene editing approach. RESULTS We found that OVCH2 is specifically expressed in the proximal caput epididymidis, and the absence of CUB2 did not affect this localization pattern. Although the absence of both CUB domains significantly reduced sperm motility and progressive motility, this effect was not manifested in a reduction in fertility over a 6-month period mating trial, which showed no significant differences between control and CUB deletant mice. Further, the absence of one or both CUB domains did not affect reproductive organ structure or sperm morphology. CONCLUSIONS Our studies demonstrate that the CUB domains are not required for fertility in male mice, at least under the normal animal housing conditions our mice were tested in, and suggest that the enzymatic activity of the OVCH2 protease, in the absence of its CUB domains, is sufficient for normal sperm processing in the epididymis. Although our findings do not preclude the possibility that OVCH2 CUB domains are required under a yet-identified stress condition, our findings demonstrate that the most likely region for deleterious mutations in men with idiopathic infertility and the most vulnerable site for inhibition of OVCH2 protein function is in its protease domain, and not its CUB domains. Our findings have implications in the genetic screening of infertile men and the development of a novel non-hormonal male contraceptive by honing in on the more critical region of a functionally required protein.
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Affiliation(s)
- Katarzyna Kent
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kaori Nozawa
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
| | - Courtney Sutton
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
| | - Frey Daniel
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Thomas X. Garcia
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
- Scott Department of Urology, Baylor College of Medicine, TX 77030, USA
| | - Martin M. Matzuk
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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Lin YC, Sahoo BK, Gau SS, Yang RB. The biology of SCUBE. J Biomed Sci 2023; 30:33. [PMID: 37237303 PMCID: PMC10214685 DOI: 10.1186/s12929-023-00925-3] [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: 02/20/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
The SCUBE [Signal peptide-Complement C1r/C1s, Uegf, Bmp1 (CUB)-Epithelial growth factor domain-containing protein] family consists of three proteins in vertebrates, SCUBE1, 2 and 3, which are highly conserved in zebrafish, mice and humans. Each SCUBE gene encodes a polypeptide of approximately 1000 amino acids that is organized into five modular domains: (1) an N-terminal signal peptide sequence, (2) nine tandem epidermal growth factor (EGF)-like repeats, (3) a large spacer region, (4) three cysteine-rich (CR) motifs, and (5) a CUB domain at the C-terminus. Murine Scube genes are expressed individually or in combination during the development of various tissues, including those in the central nervous system and the axial skeleton. The cDNAs of human SCUBE orthologs were originally cloned from vascular endothelial cells, but SCUBE expression has also been found in platelets, mammary ductal epithelium and osteoblasts. Both soluble and membrane-associated SCUBEs have been shown to play important roles in physiology and pathology. For instance, upregulation of SCUBEs has been reported in acute myeloid leukemia, breast cancer and lung cancer. In addition, soluble SCUBE1 is released from activated platelets and can be used as a clinical biomarker for acute coronary syndrome and ischemic stroke. Soluble SCUBE2 enhances distal signaling by facilitating the secretion of dual-lipidated hedgehog from nearby ligand-producing cells in a paracrine manner. Interestingly, the spacer regions and CR motifs can increase or enable SCUBE binding to cell surfaces via electrostatic or glycan-lectin interactions. As such, membrane-associated SCUBEs can function as coreceptors that enhance the signaling activity of various serine/threonine kinase or tyrosine kinase receptors. For example, membrane-associated SCUBE3 functions as a coreceptor that promotes signaling in bone morphogenesis. In humans, SCUBE3 mutations are linked to abnormalities in growth and differentiation of both bones and teeth. In addition to studies on human SCUBE function, experimental results from genetically modified mouse models have yielded important insights in the field of systems biology. In this review, we highlight novel molecular discoveries and critical directions for future research on SCUBE proteins in the context of cancer, skeletal disease and cardiovascular disease.
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Affiliation(s)
- Yuh-Charn Lin
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Binay K Sahoo
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Shiang-Shin Gau
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ruey-Bing Yang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
- Biomedical Translation Research Center, Academia Sinica, Taipei, Taiwan.
- Program in Drug Discovery and Development Industry, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
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9
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Alruwaili M, Basri R, AlRuwaili R, Albarrak AM, Ali NH. Neurological Implications of Vitamin B12 Deficiency in Diet: A Systematic Review and Meta-Analysis. Healthcare (Basel) 2023; 11:healthcare11070958. [PMID: 37046885 PMCID: PMC10094050 DOI: 10.3390/healthcare11070958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
Background: Vitamin B12 is one of the most important B-Vitamins that the human body needs on a daily basis, the lack of which can precipitate several neurological issues. Objectives: This systematic aimed to investigate the neurological implications of Vitamin B12 deficiency and the effects when B12 levels were corrected in susceptible individuals. Methods: The databases PubMed-MEDLINE, Web of Science, Cochrane, and Scopus were all searched using pertinent keywords, reference searches, and citation searches. The terms used to access the database were “Cognition”, “Dietary patterns”, “Neurology”, “Nutritional profile”, and “Vitamin B12”. Results: Vitamin B12 was shown to noticeably improve cognition and other neurological parameters in the short term in older adults and the short-to-medium term in children; however, there was no perceived increase/improvement when the Vitamin was administered in the longer term, either alone or in conjunction with other similar nutritional interventions. Conclusion: Vitamin B12’s role in the improvement of neurological functions over a long-term period remains somewhat inconclusive to date, as the majority of our selected control trials did not display much correlation between the two factors. However, Vitamin B12 did improve cognition levels in both children and older adults over a short course of administration.
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Affiliation(s)
- Mubarak Alruwaili
- Department of Internal Medicine, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia
- Correspondence: (M.A.); (R.B.)
| | - Rehana Basri
- Department of Internal Medicine, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia
- Correspondence: (M.A.); (R.B.)
| | - Raed AlRuwaili
- Department of Internal Medicine, College of Medicine, Jouf University, Sakaka 72345, Saudi Arabia
| | - Anas Mohammad Albarrak
- Department of Internal Medicine, College of Medicine, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
| | - Naif H. Ali
- Department of Internal Medicine, Medical College, Najran University, Najran 55461, Saudi Arabia
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McCorvie TJ, Ferreira D, Yue WW, Froese DS. The complex machinery of human cobalamin metabolism. J Inherit Metab Dis 2023; 46:406-420. [PMID: 36680553 DOI: 10.1002/jimd.12593] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Vitamin B12 (cobalamin, Cbl) is required as a cofactor by two human enzymes, 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR) and methylmalonyl-CoA mutase (MMUT). Within the body, a vast array of transporters, enzymes and chaperones are required for the generation and delivery of these cofactor forms. How they perform these functions is dictated by the structure and interactions of the proteins involved, the molecular bases of which are only now being elucidated. In this review, we highlight recent insights into human Cbl metabolism and address open questions in the field by employing a protein structure and interactome based perspective. We discuss how three very similar proteins-haptocorrin, intrinsic factor and transcobalamin-exploit slight structural differences and unique ligand receptor interactions to effect selective Cbl absorption and internalisation. We describe recent advances in the understanding of how endocytosed Cbl is transported across the lysosomal membrane and the implications of the recently solved ABCD4 structure. We detail how MMACHC and MMADHC cooperate to modify and target cytosolic Cbl to the client enzymes MTR and MMUT using ingenious modifications to an ancient nitroreductase fold, and how MTR and MMUT link with their accessory enzymes to sustainably harness the supernucleophilic potential of Cbl. Finally, we provide an outlook on how future studies may combine structural and interactome based approaches and incorporate knowledge of post-translational modifications to bring further insights.
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Affiliation(s)
- Thomas J McCorvie
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Douglas Ferreira
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wyatt W Yue
- Biosciences Institute, The Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital Zürich, University of Zürich, Zürich, Switzerland
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Choy C, Lim LY, Chan LW, Cui Z, Mao S, Wong TW. Exploring Intestinal Surface Receptors in Oral Nanoinsulin Delivery. Pharmacol Rev 2022; 74:962-983. [PMID: 36779351 DOI: 10.1124/pharmrev.122.000631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 06/01/2022] [Accepted: 06/24/2022] [Indexed: 11/22/2022] Open
Abstract
Subcutaneous and inhaled insulins are associated with needle phobia, lipohypertrophy, lipodystrophy, and cough in diabetes treatment. Oral nanoinsulin has been developed, reaping the physiologic benefits of peroral administration. This review profiles intestinal receptors exploitable in targeted delivery of oral nanoinsulin. Intestinal receptor targeting improves oral insulin bioavailability and sustains blood glucose-lowering response. Nonetheless, these studies are conducted in small animal models with no optimization of insulin dose, targeting ligand type and content, and physicochemical and molecular biologic characteristics of nanoparticles against the in vivo/clinical diabetes responses as a function of the intestinal receptor population characteristics with diabetes progression. The interactive effects between nanoinsulin and antidiabetic drugs on intestinal receptors, including their up-/downregulation, are uncertain. Sweet taste receptors upregulate SGLT-1, and both have an undefined role as new intestinal targets of nanoinsulin. Receptor targeting of oral nanoinsulin represents a viable approach that is relatively green, requiring an in-depth development of the relationship between receptors and their pathophysiological profiles with physicochemical attributes of the oral nanoinsulin. SIGNIFICANCE STATEMENT: Intestinal receptor targeting of oral nanoinsulin improves its bioavailability with sustained blood glucose-lowering response. Exploring new intestinal receptor and tailoring the design of oral nanoinsulin to the pathophysiological state of diabetic patients is imperative to raise the insulin performance to a comparable level as the injection products.
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Affiliation(s)
- Carlynne Choy
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
| | - Lee Yong Lim
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
| | - Lai Wah Chan
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
| | - Zhixiang Cui
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
| | - Shirui Mao
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
| | - Tin Wui Wong
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore (C.C., L.W.C., T.W.W.); Pharmacy, School of Allied Health, The University of Western Australia, 35 Stirling Highway, Crawley WA, Australia (L.Y.L.); School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China (Z.C., S.M.); Non-Destructive Biomedical and Pharmaceutical Research Centre, Smart Manufacturing Research Institute, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.); and Particle Design Research Group, Faculty of Pharmacy, Universiti Teknologi MARA Selangor, Puncak Alam, Selangor, Malaysia (T.W.W.)
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12
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Yadav SPS, Yu A, Zhao J, Singh J, Kakkar S, Chakraborty S, Mechref Y, Molitoris B, Wagner MC. Glycosylation of a key cubilin Asn residue results in reduced binding to albumin. J Biol Chem 2022; 298:102371. [PMID: 35970386 PMCID: PMC9485058 DOI: 10.1016/j.jbc.2022.102371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 10/28/2022] Open
Abstract
Kidney disease often manifests with an increase in proteinuria, which can result from both glomerular and/or proximal tubule injury. The proximal tubules are the major site of protein and peptide endocytosis of the glomerular filtrate, and cubilin is the proximal tubule brush border membrane glycoprotein receptor that binds filtered albumin and initiates its processing in proximal tubules. Albumin also undergoes multiple modifications depending upon the physiologic state. We previously documented that carbamylated albumin had reduced cubilin binding, but the effects of cubilin modifications on binding albumin remain unclear. Here, we investigate the cubilin-albumin binding interaction to define the impact of cubilin glycosylation and map the key glycosylation sites while also targeting specific changes in a rat model of proteinuria. We identified a key Asn residue, N1285, that when glycosylated reduced albumin binding. In addition, we found a pH-induced conformation change may contribute to ligand release. To further define the albumin-cubilin binding site, we determined the solution structure of cubilin's albumin-binding domain, CUB7,8, using small-angle X-ray scattering and molecular modeling. We combined this information with mass spectrometry crosslinking experiments of CUB7,8 and albumin that provides a model of the key amino acids required for cubilin-albumin binding. Together, our data supports an important role for glycosylation in regulating the cubilin interaction with albumin, which is altered in proteinuria and provides new insight into the binding interface necessary for the cubilin-albumin interaction.
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Affiliation(s)
- Shiv Pratap Singh Yadav
- Nephrology Division, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Aiying Yu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Jingfu Zhao
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Jasdeep Singh
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi, India
| | - Saloni Kakkar
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | | | - Yehia Mechref
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Bruce Molitoris
- Nephrology Division, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Mark C Wagner
- Nephrology Division, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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13
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Ge Y, Zadeh M, Mohamadzadeh M. Vitamin B12 coordinates ileal epithelial cell and microbiota functions to resist Salmonella infection in mice. J Exp Med 2022; 219:e20220057. [PMID: 35674742 PMCID: PMC9184849 DOI: 10.1084/jem.20220057] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/15/2022] [Accepted: 05/25/2022] [Indexed: 12/15/2022] Open
Abstract
Deprivation of vitamin B12 (VB12) is linked to various diseases, but the underlying mechanisms in disease progression are poorly understood. Using multiomic approaches, we elucidated the responses of ileal epithelial cells (iECs) and gut microbiome to VB12 dietary restriction. Here, VB12 deficiency impaired the transcriptional and metabolic programming of iECs and reduced epithelial mitochondrial respiration and carnitine shuttling during intestinal Salmonella Typhimurium (STm) infection. Fecal microbial and untargeted metabolomic profiling identified marked changes related to VB12 deficiency, including reductions of metabolites potentially activating mitochondrial β-oxidation in iECs and short-chain fatty acids (SCFAs). Depletion of SCFA-producing microbes by streptomycin treatment decreased the VB12-dependent STm protection. Moreover, compromised mitochondrial function of iECs correlated with declined cell capability to utilize oxygen, leading to uncontrolled oxygen-dependent STm expansion in VB12-deficient mice. Our findings uncovered previously unrecognized mechanisms through which VB12 coordinates ileal epithelial mitochondrial homeostasis and gut microbiota to regulate epithelial oxygenation, resulting in the control of aerobic STm infection.
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Affiliation(s)
- Yong Ge
- Division of Gastroenterology & Nutrition, Department of Medicine, University of Texas Health, San Antonio, TX
- Department of Infectious Diseases & Immunology, University of Florida, Gainesville, FL
| | - Mojgan Zadeh
- Division of Gastroenterology & Nutrition, Department of Medicine, University of Texas Health, San Antonio, TX
- Department of Infectious Diseases & Immunology, University of Florida, Gainesville, FL
| | - Mansour Mohamadzadeh
- Division of Gastroenterology & Nutrition, Department of Medicine, University of Texas Health, San Antonio, TX
- Department of Infectious Diseases & Immunology, University of Florida, Gainesville, FL
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14
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Molitoris BA, Sandoval RM, Yadav SPS, Wagner MC. Albumin Uptake and Processing by the Proximal Tubule: Physiologic, Pathologic and Therapeutic Implications. Physiol Rev 2022; 102:1625-1667. [PMID: 35378997 PMCID: PMC9255719 DOI: 10.1152/physrev.00014.2021] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For nearly 50 years the proximal tubule (PT) has been known to reabsorb, process, and either catabolize or transcytose albumin from the glomerular filtrate. Innovative techniques and approaches have provided insights into these processes. Several genetic diseases, nonselective PT cell defects, chronic kidney disease (CKD), and acute PT injury lead to significant albuminuria, reaching nephrotic range. Albumin is also known to stimulate PT injury cascades. Thus, the mechanisms of albumin reabsorption, catabolism, and transcytosis are being reexamined with the use of techniques that allow for novel molecular and cellular discoveries. Megalin, a scavenger receptor, cubilin, amnionless, and Dab2 form a nonselective multireceptor complex that mediates albumin binding and uptake and directs proteins for lysosomal degradation after endocytosis. Albumin transcytosis is mediated by a pH-dependent binding affinity to the neonatal Fc receptor (FcRn) in the endosomal compartments. This reclamation pathway rescues albumin from urinary losses and cellular catabolism, extending its serum half-life. Albumin that has been altered by oxidation, glycation, or carbamylation or because of other bound ligands that do not bind to FcRn traffics to the lysosome. This molecular sorting mechanism reclaims physiological albumin and eliminates potentially toxic albumin. The clinical importance of PT albumin metabolism has also increased as albumin is now being used to bind therapeutic agents to extend their half-life and minimize filtration and kidney injury. The purpose of this review is to update and integrate evolving information regarding the reabsorption and processing of albumin by proximal tubule cells including discussion of genetic disorders and therapeutic considerations.
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Affiliation(s)
- Bruce A. Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Dept.of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ruben M. Sandoval
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Shiv Pratap S. Yadav
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Mark C. Wagner
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
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15
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Kozyraki R, Verroust P, Cases O. Cubilin, the intrinsic factor-vitamin B12 receptor. VITAMINS AND HORMONES 2022; 119:65-119. [PMID: 35337634 DOI: 10.1016/bs.vh.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cubilin (CUBN), the intrinsic factor-vitamin B12 receptor is a large endocytic protein involved in various physiological functions: vitamin B12 uptake in the gut; reabsorption of albumin and maturation of vitamin D in the kidney; nutrient delivery during embryonic development. Cubilin is an atypical receptor, peripherally associated to the plasma membrane. The transmembrane proteins amnionless (AMN) and Lrp2/Megalin are the currently known molecular partners contributing to plasma membrane transport and internalization of Cubilin. The role of Cubilin/Amn complex in the handling of vitamin B12 in health and disease has extensively been studied and so is the role of the Cubilin-Lrp2 tandem in renal pathophysiology. Accumulating evidence strongly supports a role of Cubilin in some developmental defects including impaired closure of the neural tube. Are these defects primarily caused by the dysfunction of a specific Cubilin ligand or are they secondary to impaired vitamin B12 or protein uptake? We will present the established Cubilin functions, discuss the developmental data and provide an overview of the emerging implications of Cubilin in the field of cardiovascular disease and cancer pathogenesis.
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Affiliation(s)
- Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France.
| | - Pierre Verroust
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
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Yang J, Xu Y, Deng L, Zhou L, Qiu L, Zhang Y, Zhou J. CUBN gene mutations may cause focal segmental glomerulosclerosis (FSGS) in children. BMC Nephrol 2022; 23:15. [PMID: 34979989 PMCID: PMC8725476 DOI: 10.1186/s12882-021-02654-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/20/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Imerslund-Gräsbeck Syndrome (IGS) is mainly caused by CUBN gene biallelic mutations. Proteinuria accompanies IGS specific symptoms in about half of the patients, isolated proteinuria is rarely reported. Here we present 3 patients with isolated proteinuria and focal segmental glomerulosclerosis (FSGS) caused by CUBN gene biallelic pathogenic variants. METHOD Whole exome sequencing was performed on three children with isolated proteinuria. CUBN gene biallelic pathogenic variants were found and then verified by sanger sequencing. Their clinical, pathological and molecular genetic characteristics were analyzed and correlated accordingly. RESULTS All three children presented with isolated proteinuria, no megaloblastic anemia. Their urine levels of β2 microglobulin were normal or slightly higher. Renal biopsies showed focal segmental glomerulosclerosis with mild glomerular mesangial hypercellularity, partial effacement of foot processes and podocyte microvillation. Two of them were found to carry compound heterozygous mutations and one homozygous mutation of CUBN gene. Totally four CUBN gene biallelic pathogenic variants were identified, including c.9287 T > C (p.L3096P), c.122 + 1G > A, c.7906C > T (p.R2636*), c.10233G > A (p.W3411*). Except for intron splice-site mutation, all other variants are located in highly conserved sites of CUB domain for binding to albumin. CONCLUSION The results demonstrate that CUBN gene mutations may cause isolated proteinuria pathologically presented as FSGS. Our cases extend the spectrum of renal manifestation and genotype of CUBN gene mutations.
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Affiliation(s)
- Jing Yang
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China
| | - Yongli Xu
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China
| | - Linxia Deng
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China
| | - Luowen Zhou
- Department of Neurosurgery, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Wuhan, China
| | - Liru Qiu
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China
| | - Yu Zhang
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China
| | - Jianhua Zhou
- Department of Pediatrics, Tongji Hospital, Tongji Medical college, Huazhong University of Science and Technology, Jiefang Ave. No. 1095, Wuhan, 430030, China.
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17
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Roth W, Mohamadzadeh M. Vitamin B12 and gut-brain homeostasis in the pathophysiology of ischemic stroke. EBioMedicine 2021; 73:103676. [PMID: 34749301 PMCID: PMC8586745 DOI: 10.1016/j.ebiom.2021.103676] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/14/2021] [Accepted: 10/22/2021] [Indexed: 12/31/2022] Open
Abstract
Stroke is a leading cause of morbidity and mortality worldwide. It inflicts immeasurable suffering on patients and their loved ones and carries an immense social cost. Efforts to mitigate the impact of stroke have focused on identifying therapeutic targets for the prevention and treatment. The gut microbiome represents one such potential target given its multifaceted effects on conditions known to cause and worsen the severity of stroke. Vitamin B12 (VB12) serves as a cofactor for two enzymes, methylmalonyl-CoA synthase and methionine synthase, vital for methionine and nucleotide biosynthesis. VB12 deficiency results in a buildup of metabolic substrates, such as homocysteine, that alter immune homeostasis and contribute to atherosclerotic disorders, including ischemic stroke. In addition to its support of cellular function, VB12 serves as a metabolic cofactor for gut microbes. By shaping microbial communities, VB12 further impacts local and peripheral immunity. Growing evidence suggests that gut dysbiosis-related immune dysfunction induced by VB12 deficiency may potentially contributes to stroke pathogenesis, its severity, and patient outcomes. In this review, we discuss the complex interactions of VB12, gut microbes and the associated metabolites, and immune homeostasis throughout the natural history of ischemic stroke.
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Affiliation(s)
- William Roth
- Department of Neurology, University of Florida, Gainesville, FL 32608, USA.
| | - Mansour Mohamadzadeh
- Division of Gastroenterology & Nutrition, Department of Medicine, College of Medicine, University of Texas Health, San Antonio, TX, USA.
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18
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Rosa M, Noel T, Harris M, Ladds G. Emerging roles of adhesion G protein-coupled receptors. Biochem Soc Trans 2021; 49:1695-1709. [PMID: 34282836 PMCID: PMC8421042 DOI: 10.1042/bst20201144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/24/2022]
Abstract
Adhesion G protein-coupled receptors (aGPCRs) form a sub-group within the GPCR superfamily. Their distinctive structure contains an abnormally large N-terminal, extracellular region with a GPCR autoproteolysis-inducing (GAIN) domain. In most aGPCRs, the GAIN domain constitutively cleaves the receptor into two fragments. This process is often required for aGPCR signalling. Over the last two decades, much research has focussed on aGPCR-ligand interactions, in an attempt to deorphanize the family. Most ligands have been found to bind to regions N-terminal to the GAIN domain. These receptors may bind a variety of ligands, ranging across membrane-bound proteins and extracellular matrix components. Recent advancements have revealed a conserved method of aGPCR activation involving a tethered ligand within the GAIN domain. Evidence for this comes from increased activity in receptor mutants exposing the tethered ligand. As a result, G protein-coupling partners of aGPCRs have been more extensively characterised, making use of their tethered ligand to create constitutively active mutants. This has led to demonstrations of aGPCR function in, for example, neurodevelopment and tumour growth. However, questions remain around the ligands that may bind many aGPCRs, how this binding is translated into changes in the GAIN domain, and the exact mechanism of aGPCR activation following GAIN domain conformational changes. This review aims to examine the current knowledge around aGPCR activation, including ligand binding sites, the mechanism of GAIN domain-mediated receptor activation and how aGPCR transmembrane domains may relate to activation. Other aspects of aGPCR signalling will be touched upon, such as downstream effectors and physiological roles.
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Affiliation(s)
- Matthew Rosa
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Timothy Noel
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K
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19
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Kim HJ, Xu Y, Petri A, Vanhoorelbeke K, Crawley JTB, Emsley J. Crystal structure of ADAMTS13 CUB domains reveals their role in global latency. SCIENCE ADVANCES 2021; 7:7/16/eabg4403. [PMID: 33863735 PMCID: PMC8051872 DOI: 10.1126/sciadv.abg4403] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/26/2021] [Indexed: 06/12/2023]
Abstract
ADAMTS13 is a plasma metalloprotease that is essential for the regulation of von Willebrand factor (VWF) function, mediator of platelet recruitment to sites of blood vessel damage. ADAMTS13 function is dynamically regulated by structural changes induced by VWF binding that convert it from a latent to active conformation. ADAMTS13 global latency is manifest by the interaction of its C-terminal CUB1-2 domains with its central Spacer domain. We resolved the crystal structure of the ADAMTS13 CUB1-2 domains revealing a previously unreported configuration for the tandem CUB domains. Docking simulations between the CUB1-2 domains with the Spacer domain in combination with enzyme kinetic functional characterization of ADAMTS13 CUB domain mutants enabled the mapping of the CUB1-2 domain site that binds the Spacer domain. Together, these data reveal the molecular basis of the ADAMTS13 Spacer-CUB interaction and the control of ADAMTS13 global latency.
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Affiliation(s)
- H J Kim
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Y Xu
- Department of Immunology and Inflammation, Imperial College London, London, UK
| | - A Petri
- Department of Immunology and Inflammation, Imperial College London, London, UK
| | - K Vanhoorelbeke
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - J T B Crawley
- Department of Immunology and Inflammation, Imperial College London, London, UK.
| | - J Emsley
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, UK.
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20
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Abstract
Albuminuria acts as a marker of progressive chronic kidney disease and as an indicator for initiation of hypertension treatment via modulation of the renin-angiotensin-aldosterone system with angiotensin receptor blockers or angiotensin-converting enzyme inhibitors. However, the true significance of albuminuria has yet to be fully defined. Is it merely a marker of underlying pathophysiology, or does it play a causal role in the progression of kidney disease? The answer remains under debate. In this issue of the JCI, Bedin et al. used next-generation sequencing data to identify patients with chronic proteinuria who had biallelic variants in the cubilin gene (CUBN). Through investigation of these pathogenic mutations in CUBN, the authors have further illuminated the clinical implications of albuminuria.
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21
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Urae S, Harita Y, Udagawa T, Ode KL, Nagahama M, Kajiho Y, Kanda S, Saito A, Ueda HR, Nangaku M, Oka A. A cellular model of albumin endocytosis uncovers a link between membrane and nuclear proteins. J Cell Sci 2020; 133:jcs242859. [PMID: 32482797 DOI: 10.1242/jcs.242859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 05/20/2020] [Indexed: 12/21/2022] Open
Abstract
Cubilin (CUBN) and amnionless (AMN), expressed in kidney and intestine, form a multiligand receptor complex called CUBAM that plays a crucial role in albumin absorption. To date, the mechanism of albumin endocytosis mediated by CUBAM remains to be elucidated. Here, we describe a quantitative assay to evaluate albumin uptake by CUBAM using cells expressing full-length CUBN and elucidate the crucial roles of the C-terminal part of CUBN and the endocytosis signal motifs of AMN in albumin endocytosis. We also demonstrate that nuclear valosin-containing protein-like 2 (NVL2), an interacting protein of AMN, is involved in this process. Although NVL2 was mainly localized in the nucleolus in cells without AMN expression, it was translocated to the extranuclear compartment when coexpressed with AMN. NVL2 knockdown significantly impaired internalization of the CUBN-albumin complex in cultured cells, demonstrating an involvement of NVL2 in endocytic regulation. These findings uncover a link between membrane and nucleolar proteins that is involved in endocytic processes.
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Affiliation(s)
- Seiya Urae
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
- Division of Nephrology and Endocrinology, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Yutaka Harita
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Tomohiro Udagawa
- Department of Pediatrics and Developmental Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Koji L Ode
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Masami Nagahama
- Laboratory of Molecular and Cellular Biochemistry, Meiji Pharmaceutical University, Kiyose-shi, Tokyo 204-8588, Japan
| | - Yuko Kajiho
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Shoichiro Kanda
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Akihiko Saito
- Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata-shi, Niigata 951-8510, Japan
| | - Hiroki R Ueda
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8654, Japan
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Wako-shi, Saitama 351-0198, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Akira Oka
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan
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22
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Structural basis for adhesion G protein-coupled receptor Gpr126 function. Nat Commun 2020; 11:194. [PMID: 31924782 PMCID: PMC6954182 DOI: 10.1038/s41467-019-14040-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022] Open
Abstract
Many drugs target the extracellular regions (ECRs) of cell-surface receptors. The large and alternatively-spliced ECRs of adhesion G protein-coupled receptors (aGPCRs) have key functions in diverse biological processes including neurodevelopment, embryogenesis, and tumorigenesis. However, their structures and mechanisms of action remain unclear, hampering drug development. The aGPCR Gpr126/Adgrg6 regulates Schwann cell myelination, ear canal formation, and heart development; and GPR126 mutations cause myelination defects in human. Here, we determine the structure of the complete zebrafish Gpr126 ECR and reveal five domains including a previously unknown domain. Strikingly, the Gpr126 ECR adopts a closed conformation that is stabilized by an alternatively spliced linker and a conserved calcium-binding site. Alternative splicing regulates ECR conformation and receptor signaling, while mutagenesis of the calcium-binding site abolishes Gpr126 function in vivo. These results demonstrate that Gpr126 ECR utilizes a multi-faceted dynamic approach to regulate receptor function and provide relevant insights for ECR-targeted drug design. The extracellular regions (ECRs) of adhesion GPCRs have diverse biological functions, but their structures and mechanisms of action remain unclear. Here, the authors solve the ECR structure of the Gpr126 receptor and show that ECR conformation and signaling functions are regulated by alternative splicing.
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23
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Bedin M, Boyer O, Servais A, Li Y, Villoing-Gaudé L, Tête MJ, Cambier A, Hogan J, Baudouin V, Krid S, Bensman A, Lammens F, Louillet F, Ranchin B, Vigneau C, Bouteau I, Isnard-Bagnis C, Mache CJ, Schäfer T, Pape L, Gödel M, Huber TB, Benz M, Klaus G, Hansen M, Latta K, Gribouval O, Morinière V, Tournant C, Grohmann M, Kuhn E, Wagner T, Bole-Feysot C, Jabot-Hanin F, Nitschké P, Ahluwalia TS, Köttgen A, Andersen CBF, Bergmann C, Antignac C, Simons M. Human C-terminal CUBN variants associate with chronic proteinuria and normal renal function. J Clin Invest 2020; 130:335-344. [PMID: 31613795 PMCID: PMC6934218 DOI: 10.1172/jci129937] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUNDProteinuria is considered an unfavorable clinical condition that accelerates renal and cardiovascular disease. However, it is not clear whether all forms of proteinuria are damaging. Mutations in CUBN cause Imerslund-Gräsbeck syndrome (IGS), which is characterized by intestinal malabsorption of vitamin B12 and in some cases proteinuria. CUBN encodes for cubilin, an intestinal and proximal tubular uptake receptor containing 27 CUB domains for ligand binding.METHODSWe used next-generation sequencing for renal disease genes to genotype cohorts of patients with suspected hereditary renal disease and chronic proteinuria. CUBN variants were analyzed using bioinformatics, structural modeling, and epidemiological methods.RESULTSWe identified 39 patients, in whom biallelic pathogenic variants in the CUBN gene were associated with chronic isolated proteinuria and early childhood onset. Since the proteinuria in these patients had a high proportion of albuminuria, glomerular diseases such as steroid-resistant nephrotic syndrome or Alport syndrome were often the primary clinical diagnosis, motivating renal biopsies and the use of proteinuria-lowering treatments. However, renal function was normal in all cases. By contrast, we did not found any biallelic CUBN variants in proteinuric patients with reduced renal function or focal segmental glomerulosclerosis. Unlike the more N-terminal IGS mutations, 37 of the 41 proteinuria-associated CUBN variants led to modifications or truncations after the vitamin B12-binding domain. Finally, we show that 4 C-terminal CUBN variants are associated with albuminuria and slightly increased GFR in meta-analyses of large population-based cohorts.CONCLUSIONCollectively, our data suggest an important role for the C-terminal half of cubilin in renal albumin reabsorption. Albuminuria due to reduced cubilin function could be an unexpectedly common benign condition in humans that may not require any proteinuria-lowering treatment or renal biopsy.FUNDINGATIP-Avenir program, Fondation Bettencourt-Schueller (Liliane Bettencourt Chair of Developmental Biology), Agence Nationale de la Recherche (ANR) Investissements d'avenir program (ANR-10-IAHU-01) and NEPHROFLY (ANR-14-ACHN-0013, to MS), Steno Collaborative Grant 2018 (NNF18OC0052457, to TSA and MS), Heisenberg Professorship of the German Research Foundation (KO 3598/5-1, to AK), Deutsche Forschungsgemeinschaft (DFG) Collaborative Research Centre (SFB) KIDGEM 1140 (project 246781735, to CB), and Federal Ministry of Education and Research (BMB) (01GM1515C, to CB).
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Affiliation(s)
| | - Olivia Boyer
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Pediatric Nephrology and
| | - Aude Servais
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Nephrology, Necker Hospital, Assistance Publique Hôpitaux de Paris (APHP), Paris, France
| | - Yong Li
- Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Marie-Josephe Tête
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
| | - Alexandra Cambier
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | - Julien Hogan
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | - Veronique Baudouin
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | | | | | - Florie Lammens
- Centre Hospitalier Régional Universitaire de Lille, Lille, France
| | | | - Bruno Ranchin
- Department of Pediatric Nephrology, Hospices Civils de Lyon, Bron, France
| | - Cecile Vigneau
- Centre Hospitalier Universitaire de Rennes, INSERM U1085 IRSET-9, Rennes, France
| | - Iseline Bouteau
- Centre Hospitalier Universitaire de Poitiers, Poitiers, France
| | | | | | - Tobias Schäfer
- Renal Division, University Medical Center Freiburg, Freiburg, Germany
| | - Lars Pape
- Department of Pediatric Kidney, Liver and Metabolic Disease, Hannover Medical School, Hannover, Germany
| | - Markus Gödel
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B. Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Günter Klaus
- Department of Child and Adolescent Medicine, University Medical Center Marburg-Giessen, Marburg, Germany
| | - Matthias Hansen
- KfH-Nierenzentrum für Kinder und Jugendliche und Clementine-Kinderhospital, Frankfurt, Germany
| | - Kay Latta
- KfH-Nierenzentrum für Kinder und Jugendliche und Clementine-Kinderhospital, Frankfurt, Germany
| | - Olivier Gribouval
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
| | | | - Carole Tournant
- Department of Genetics, Necker Hospital, APHP, Paris, France
| | - Maik Grohmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
- Center for Human Genetics, Mainz, Germany
| | - Elisa Kuhn
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Timo Wagner
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Christine Bole-Feysot
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | - Fabienne Jabot-Hanin
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | - Patrick Nitschké
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | | | - Anna Köttgen
- Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Carsten Bergmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
- Center for Human Genetics, Mainz, Germany
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Corinne Antignac
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Genetics, Necker Hospital, APHP, Paris, France
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24
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Bedin M, Boyer O, Servais A, Li Y, Villoing-Gaudé L, Tête MJ, Cambier A, Hogan J, Baudouin V, Krid S, Bensman A, Lammens F, Louillet F, Ranchin B, Vigneau C, Bouteau I, Isnard-Bagnis C, Mache CJ, Schäfer T, Pape L, Gödel M, Huber TB, Benz M, Klaus G, Hansen M, Latta K, Gribouval O, Morinière V, Tournant C, Grohmann M, Kuhn E, Wagner T, Bole-Feysot C, Jabot-Hanin F, Nitschké P, Ahluwalia TS, Köttgen A, Andersen CBF, Bergmann C, Antignac C, Simons M. Human C-terminal CUBN variants associate with chronic proteinuria and normal renal function. J Clin Invest 2020. [PMID: 31613795 DOI: 10.1172/jci12937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023] Open
Abstract
BACKGROUNDProteinuria is considered an unfavorable clinical condition that accelerates renal and cardiovascular disease. However, it is not clear whether all forms of proteinuria are damaging. Mutations in CUBN cause Imerslund-Gräsbeck syndrome (IGS), which is characterized by intestinal malabsorption of vitamin B12 and in some cases proteinuria. CUBN encodes for cubilin, an intestinal and proximal tubular uptake receptor containing 27 CUB domains for ligand binding.METHODSWe used next-generation sequencing for renal disease genes to genotype cohorts of patients with suspected hereditary renal disease and chronic proteinuria. CUBN variants were analyzed using bioinformatics, structural modeling, and epidemiological methods.RESULTSWe identified 39 patients, in whom biallelic pathogenic variants in the CUBN gene were associated with chronic isolated proteinuria and early childhood onset. Since the proteinuria in these patients had a high proportion of albuminuria, glomerular diseases such as steroid-resistant nephrotic syndrome or Alport syndrome were often the primary clinical diagnosis, motivating renal biopsies and the use of proteinuria-lowering treatments. However, renal function was normal in all cases. By contrast, we did not found any biallelic CUBN variants in proteinuric patients with reduced renal function or focal segmental glomerulosclerosis. Unlike the more N-terminal IGS mutations, 37 of the 41 proteinuria-associated CUBN variants led to modifications or truncations after the vitamin B12-binding domain. Finally, we show that 4 C-terminal CUBN variants are associated with albuminuria and slightly increased GFR in meta-analyses of large population-based cohorts.CONCLUSIONCollectively, our data suggest an important role for the C-terminal half of cubilin in renal albumin reabsorption. Albuminuria due to reduced cubilin function could be an unexpectedly common benign condition in humans that may not require any proteinuria-lowering treatment or renal biopsy.FUNDINGATIP-Avenir program, Fondation Bettencourt-Schueller (Liliane Bettencourt Chair of Developmental Biology), Agence Nationale de la Recherche (ANR) Investissements d'avenir program (ANR-10-IAHU-01) and NEPHROFLY (ANR-14-ACHN-0013, to MS), Steno Collaborative Grant 2018 (NNF18OC0052457, to TSA and MS), Heisenberg Professorship of the German Research Foundation (KO 3598/5-1, to AK), Deutsche Forschungsgemeinschaft (DFG) Collaborative Research Centre (SFB) KIDGEM 1140 (project 246781735, to CB), and Federal Ministry of Education and Research (BMB) (01GM1515C, to CB).
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Affiliation(s)
| | - Olivia Boyer
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Pediatric Nephrology and
| | - Aude Servais
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Nephrology, Necker Hospital, Assistance Publique Hôpitaux de Paris (APHP), Paris, France
| | - Yong Li
- Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Marie-Josephe Tête
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
| | - Alexandra Cambier
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | - Julien Hogan
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | - Veronique Baudouin
- Department of Pediatric Nephrology and Transplantation, Robert-Debré Hospital, APHP, Paris, France
| | | | | | - Florie Lammens
- Centre Hospitalier Régional Universitaire de Lille, Lille, France
| | | | - Bruno Ranchin
- Department of Pediatric Nephrology, Hospices Civils de Lyon, Bron, France
| | - Cecile Vigneau
- Centre Hospitalier Universitaire de Rennes, INSERM U1085 IRSET-9, Rennes, France
| | - Iseline Bouteau
- Centre Hospitalier Universitaire de Poitiers, Poitiers, France
| | | | | | - Tobias Schäfer
- Renal Division, University Medical Center Freiburg, Freiburg, Germany
| | - Lars Pape
- Department of Pediatric Kidney, Liver and Metabolic Disease, Hannover Medical School, Hannover, Germany
| | - Markus Gödel
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Günter Klaus
- Department of Child and Adolescent Medicine, University Medical Center Marburg-Giessen, Marburg, Germany
| | - Matthias Hansen
- KfH-Nierenzentrum für Kinder und Jugendliche und Clementine-Kinderhospital, Frankfurt, Germany
| | - Kay Latta
- KfH-Nierenzentrum für Kinder und Jugendliche und Clementine-Kinderhospital, Frankfurt, Germany
| | - Olivier Gribouval
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
| | | | - Carole Tournant
- Department of Genetics, Necker Hospital, APHP, Paris, France
| | - Maik Grohmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
- Center for Human Genetics, Mainz, Germany
| | - Elisa Kuhn
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Timo Wagner
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Christine Bole-Feysot
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | - Fabienne Jabot-Hanin
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | - Patrick Nitschké
- Bioinformatic Platform, INSERM UMR 1163, Institut Imagine, Paris, France
- Bioinformatics Core Facility, Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Université de Paris, Paris, France
| | | | - Anna Köttgen
- Institute of Genetic Epidemiology, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Carsten Bergmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
- Center for Human Genetics, Mainz, Germany
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Corinne Antignac
- Laboratory of Hereditary Kidney Disease, Imagine Institute, INSERM U1163, Université de Paris, Paris, France
- Department of Genetics, Necker Hospital, APHP, Paris, France
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25
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Systemically Administered Plant Recombinant Holo-Intrinsic Factor Targets the Liver and is not Affected by Endogenous B12 levels. Sci Rep 2019; 9:12269. [PMID: 31439908 PMCID: PMC6706418 DOI: 10.1038/s41598-019-48555-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 08/06/2019] [Indexed: 01/09/2023] Open
Abstract
Precision targeting imaging agents and/or treatment agents to select cells or organs in the body remains a significant need and is an area of intense research. It has been hypothesized that the vitamin B12 (B12) dietary pathway, or components thereof, may be exploitable in this area. The question of whether gastric Intrinsic factor (IF), critical for B12 absorption in the GI tract via the cubilin receptor, could be used as a targeting moiety for the cubilin receptor systemically, has not been investigated. Cubilin is the only known receptor for holo-IF and is found primarily in the kidney and ear (outside of the ileum of the GI) offering significant scope for specific targeting. We utilized plant derived human gastric IF in fluorescent cell and PET based in vivo imaging and biodistribution studies and demonstrated that plant derived IF primarily targets the liver, likely a consequence of the unique glycosylation profile of the IF, and is not affected by endogenous B12 levels.
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26
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He PP, Li XD, Wang L, Wang H. Bispyrene-Based Self-Assembled Nanomaterials: In Vivo Self-Assembly, Transformation, and Biomedical Effects. Acc Chem Res 2019; 52:367-378. [PMID: 30653298 DOI: 10.1021/acs.accounts.8b00398] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Self-assembled nanomaterials show potential high efficiency as theranostic agents for high-performance imaging and therapy. However, superstructures and properties of preassembled nanomaterials are somewhat compromised under complicated physiological conditions. Given the advantages of the dynamic nature and adaptive behavior of self-assembly systems, we propose an "in vivo self-assembly" strategy for in situ construction of nanomaterials in living objects. For the proof-of-concept study of in vivo self-assembly, we developed a bispyrene (BP) molecule as a multifunctional building block. BP molecules show nonfluorescence in the monomeric state. Quantum-chemical calculations indicate that BP forms twisted intramolecular charge transfer states, which are separated into two orthogonal units, preventing the fluorescence emission. Interestingly, the typical excimeric emission of BP is observed with the formation of J-type aggregates, as confirmed by single-crystal X-ray diffraction. Packing of the BP molecules generates parallel pyrene units that interact with adjacent ones in a slipped face-to-face fashion through intermolecular π-π interactions. BP and/or its amphiphilic derivatives are capable of self-aggregating into nanoparticles (NPs) in aqueous solution because of the hydrophobic and π-π interactions of BP. Upon specific biological stimuli, BP NPs can be transformed into variable self-assembled superstructures. Importantly, the self-assembled BP NPs exhibit turn-on fluorescence signals that can be used to monitor the self-assembly/disassembly process in vitro and in vivo. On the basis of the photophysical properties of BP and its aggregates, we synthesized a series of designed BP derivatives as building blocks for in situ construction of functional nanomaterials for bioimaging and/or therapeutics. We observed several new biomedical effects, e.g., (i) the assembly/aggregation-induced retention (AIR) effect, which shows improved accumulation and retention of bioactive nanomaterials in the regions of interests; (ii) the transformation-induced surface adhesion (TISA) effect, which means the BP NPs transform into nanofibers (NFs) on cell surfaces upon binding with specific receptors, which leads to less uptake of BP NPs by cells via traditional endocytosis pathway; and (iii) transformation of the BP NPs into NFs in the tumor microenvironment, showing high accumulation and long-term retention, revealing the transformation-enhanced accumulation and retention (TEAR) effect. In this Account, we summarize the fluorescence property and emission mechanism of BP building blocks upon aggregation in the biological environment. Moreover, BP-derived compounds used for in vivo self-assembly and transformation are introduced involving modulation strategies. Subsequently, unexpected biomedical effects and applications for theranostics of BP based nanomaterials are discussed. We finally conclude with an outlook toward future developments of BP-based self-assembled nanomaterials.
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Affiliation(s)
- Ping-Ping He
- Key Laboratory of Chemistry and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, 182 Minzu Road, Hongshan District, Wuhan, Hubei 430074, China
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology (NCNST), No. 11 Beiyitiao, Zhongguancun, Haidian District, Beijing 100190, China
| | - Xiang-Dan Li
- Key Laboratory of Chemistry and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, 182 Minzu Road, Hongshan District, Wuhan, Hubei 430074, China
| | - Lei Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology (NCNST), No. 11 Beiyitiao, Zhongguancun, Haidian District, Beijing 100190, China
| | - Hao Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology (NCNST), No. 11 Beiyitiao, Zhongguancun, Haidian District, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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27
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Structural assembly of the megadalton-sized receptor for intestinal vitamin B 12 uptake and kidney protein reabsorption. Nat Commun 2018; 9:5204. [PMID: 30523278 PMCID: PMC6283879 DOI: 10.1038/s41467-018-07468-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/01/2018] [Indexed: 11/08/2022] Open
Abstract
The endocytic receptor cubam formed by the 460-kDa protein cubilin and the 45-kDa transmembrane protein amnionless (AMN), is essential for intestinal vitamin B12 (B12) uptake and for protein (e.g. albumin) reabsorption from the kidney filtrate. Loss of function of any of the two components ultimately leads to serious B12 deficiency and urinary protein loss in humans (Imerslund-Gräsbeck’s syndrome, IGS). Here, we present the crystal structure of AMN in complex with the amino-terminal region of cubilin, revealing a sophisticated assembly of three cubilin subunits combining into a single intertwined β-helix domain that docks to a corresponding three-faced β-helix domain in AMN. This β-helix-β-helix association thereby anchors three ligand-binding cubilin subunits to the transmembrane AMN. Electron microscopy of full-length cubam reveals a 700–800 Å long tree-like structure with the potential of dimerization into an even larger complex. Furthermore, effects of known human mutations causing IGS are explained by the structural information. Cubilin and the transmembrane protein amnionless (AMN) form the endocytic receptor cubam that is essential for intestinal vitamin B12 uptake. Here the authors present the 2.3 Å crystal structure of AMN in complex with the amino-terminal region of cubilin and discuss cubam architecture and disease causing mutations.
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28
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Benoit CR, Stanton AE, Tartanian AC, Motzer AR, McGaughey DM, Bond SR, Brody LC. Functional and phylogenetic characterization of noncanonical vitamin B 12-binding proteins in zebrafish suggests involvement in cobalamin transport. J Biol Chem 2018; 293:17606-17621. [PMID: 30237171 PMCID: PMC6231144 DOI: 10.1074/jbc.ra118.005323] [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: 08/10/2018] [Revised: 09/13/2018] [Indexed: 12/19/2022] Open
Abstract
In humans, transport of food-derived cobalamin (vitamin B12) from the digestive system into the bloodstream involves three paralogous proteins: transcobalamin (TC), haptocorrin (HC), and intrinsic factor (IF). Each of these proteins contains two domains, an α-domain and a β-domain, which together form a cleft in which cobalamin binds. Zebrafish (Danio rerio) are thought to possess only a single cobalamin transport protein, referred to as Tcn2, which is a transcobalamin homolog. Here, we used CRISPR/Cas9 mutagenesis to create null alleles of tcn2 in zebrafish. Fish homozygous for tcn2-null alleles were viable and exhibited no obvious developmentally or behaviorally abnormal phenotypes. For this reason, we hypothesized that previously unidentified cobalamin-carrier proteins encoded in the zebrafish genome may provide an additional pathway for cobalamin transport. We identified genes predicted to code for two such proteins, Tcn-beta-a (Tcnba) and Tcn-beta-b (Tcnbb), which differ from all previously characterized cobalamin transport proteins as they lack the α-domain. These β-domain-only proteins are representative of an undescribed class of cobalamin-carrier proteins that are highly conserved throughout the ray-finned fishes. We observed that the genes encoding the three cobalamin transport homologs, tcn2, tcnba, and tcnbb, are expressed in unique spatial and temporal patterns in the developing zebrafish. Moreover, exogenously expressed recombinant Tcnba and Tcnbb bound cobalamin with high affinity, comparable with binding by full-length Tcn2. Taken together, our results suggest that this noncanonical protein structure has evolved to fully function as a cobalamin-carrier protein, thereby allowing for a compensatory cobalamin transport mechanism in the tcn2-/- zebrafish.
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Affiliation(s)
- Courtney R Benoit
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Abigail E Stanton
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Aileen C Tartanian
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Andrew R Motzer
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - David M McGaughey
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Stephen R Bond
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892
| | - Lawrence C Brody
- From the Gene and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892 and
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29
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Kozyraki R, Cases O. Cubilin, the Intrinsic Factor-Vitamin B12 Receptor in Development and Disease. Curr Med Chem 2018; 27:3123-3150. [PMID: 30295181 DOI: 10.2174/0929867325666181008143945] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 08/11/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Gp280/Intrinsic factor-vitamin B12 receptor/Cubilin (CUBN) is a large endocytic receptor serving multiple functions in vitamin B12 homeostasis, renal reabsorption of protein or toxic substances including albumin, vitamin D-binding protein or cadmium. Cubilin is a peripheral membrane protein consisting of 8 Epidermal Growth Factor (EGF)-like repeats and 27 CUB (defined as Complement C1r/C1s, Uegf, BMP1) domains. This structurally unique protein interacts with at least two molecular partners, Amnionless (AMN) and Lrp2/Megalin. AMN is involved in appropriate plasma membrane transport of Cubilin whereas Lrp2 is essential for efficient internalization of Cubilin and its ligands. Observations gleaned from animal models with Cubn deficiency or human diseases demonstrate the importance of this protein. In this review addressed to basic research and medical scientists, we summarize currently available data on Cubilin and its implication in renal and intestinal biology. We also discuss the role of Cubilin as a modulator of Fgf8 signaling during embryonic development and propose that the Cubilin-Fgf8 interaction may be relevant in human pathology, including in cancer progression, heart or neural tube defects. We finally provide experimental elements suggesting that some aspects of Cubilin physiology might be relevant in drug design.
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Affiliation(s)
- Renata Kozyraki
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
| | - Olivier Cases
- INSERM UMRS 1138, Centre de Recherche des Cordeliers, Paris-Diderot University, Paris, France
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30
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Salinas M, Flores E, López-Garrigós M, Leiva-Salinas C. Vitamin B12 deficiency and clinical laboratory: Lessons revisited and clarified in seven questions. Int J Lab Hematol 2018; 40 Suppl 1:83-88. [PMID: 29741251 DOI: 10.1111/ijlh.12833] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 03/22/2018] [Indexed: 11/26/2022]
Abstract
The objective of this review article is to address the most frequently asked questions that pathologists and primary care physicians might face when dealing with a patient with suspicion of vitamin B12 deficiency. More specifically, the article mainly discusses the importance and prevalence of the deficit, how to recognize it, and the important role of a prompt diagnosis confirmation based on laboratory biomarkers for efficient replacement therapy.
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Affiliation(s)
- M Salinas
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain.,Department of Biochemistry and Molecular Pathology, Universidad Miguel Hernandez, Elche, Spain
| | - E Flores
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain.,Department of Clinic Medicine, Universidad Miguel Hernandez, Elche, Spain
| | - M López-Garrigós
- Clinical Laboratory, Hospital Universitario de San Juan, San Juan de Alicante, Spain
| | - C Leiva-Salinas
- Department of Clinical Radiology, University of Missouri Health, Columbia, MO, USA
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31
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Abstract
Nine compounds are classified as water-soluble vitamins, eight B vitamins and one vitamin C. The vitamins are mandatory for the function of numerous enzymes and lack of one or more of the vitamins may lead to severe medical conditions. All the vitamins are supplied by food in microgram to milligram quantities and in addition some of the vitamins are synthesized by the intestinal microbiota. In the gastrointestinal tract, the vitamins are liberated from binding proteins and for some of the vitamins modified prior to absorption. Due to their solubility in water, they all require specific carriers to be absorbed. Our current knowledge concerning each of the vitamins differs in depth and focus and is influenced by the prevalence of conditions and diseases related to lack of the individual vitamin. Because of that we have chosen to cover slightly different aspects for the individual vitamins. For each of the vitamins, we summarize the physiological role, the steps involved in the absorption, and the factors influencing the absorption. In addition, for some of the vitamins, the molecular base for absorption is described in details, while for others new aspects of relevance for human deficiency are included. © 2018 American Physiological Society. Compr Physiol 8:1291-1311, 2018.
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Affiliation(s)
- Hamid M Said
- University of California-School of Medicine, Irvine, California, USA.,VA Medical Center, Long Beach, California, USA
| | - Ebba Nexo
- Department of Clinical Medicine, Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
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32
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Pulido D, Sharma U, Vadon-Le Goff S, Hussain SA, Cordes S, Mariano N, Bettler E, Moali C, Aghajari N, Hohenester E, Hulmes DJS. Structural Basis for the Acceleration of Procollagen Processing by Procollagen C-Proteinase Enhancer-1. Structure 2018; 26:1384-1392.e3. [PMID: 30078642 PMCID: PMC6372009 DOI: 10.1016/j.str.2018.06.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/18/2018] [Accepted: 06/28/2018] [Indexed: 11/06/2022]
Abstract
Procollagen C-proteinase enhancer-1 (PCPE-1) is a secreted protein that specifically accelerates proteolytic release of the C-propeptides from fibrillar procollagens, a crucial step in fibril assembly. As such, it is a potential therapeutic target to improve tissue repair and prevent fibrosis, a major cause of mortality worldwide. Here we present the crystal structure of the active CUB1CUB2 fragment of PCPE-1 bound to the C-propeptide trimer of procollagen III (CPIII). This shows that the two CUB domains bind to two different chains of CPIII and that the N-terminal region of one CPIII chain, close to the proteolytic cleavage site, lies in the cleft between CUB1 and CUB2. This suggests that enhancing activity involves unraveling of this chain from the rest of the trimer, thus facilitating the action of the proteinase involved. Support for this hypothesis comes from site-directed mutagenesis, enzyme assays, binding studies, and molecular modeling. The crystal structure of PCPE-1 bound to the C-propeptides has been determined The N terminus of one propeptide chain binds to the CUB1CUB2 fragment of PCPE-1 PCPE-1 seems to unravel the propeptide trimer to enable proteolytic release Molecular modeling with the proteinase and its substrate supports this hypothesis
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Affiliation(s)
- David Pulido
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Urvashi Sharma
- UMR5086, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France
| | | | | | - Sarah Cordes
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Natacha Mariano
- UMR5305, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France
| | - Emmanuel Bettler
- UMR5305, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France
| | - Catherine Moali
- UMR5305, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France
| | - Nushin Aghajari
- UMR5086, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France
| | | | - David J S Hulmes
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; UMR5305, CNRS/Université Claude Bernard Lyon 1, 69367 Lyon Cedex 7, France.
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Abstract
The biosynthesis of B12, involving up to 30 different enzyme-mediated steps, only occurs in bacteria. Thus, most eukaryotes require an external source of B12, and yet the vitamin appears to have only two functions in eukaryotes: as a cofactor for the enzymes methionine synthase and methylmalonylCoA mutase. These two functions are crucial for normal health in humans, and in particular, the formation of methionine is essential for providing methyl groups for over 100 methylation processes. Interference with the methionine synthase reaction not only depletes the body of methyl groups but also leads to the accumulation of homocysteine, a risk factor for many diseases. The syndrome pernicious anemia, characterized by lack of intrinsic factor, leads to a severe, sometimes fatal form of B12 deficiency. However, there is no sharp cutoff for B12 deficiency; rather, there is a continuous inverse relationship between serum B12 and a variety of undesirable outcomes, including neural tube defects, stroke, and dementia. The brain is particularly vulnerable; in children, inadequate B12 stunts brain and intellectual development. Suboptimal B12 status (serum B12<300pmol/L) is very common, occurring in 30%-60% of the population, in particular in pregnant women and in less-developed countries. Thus, many tens of millions of people in the world may suffer harm from having a poor B12 status. Public health steps are urgently needed to correct this inadequacy.
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Affiliation(s)
- A David Smith
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom.
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Helga Refsum
- Department of Nutrition, University of Oslo, Oslo, Norway
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Slater PG, Gutierrez-Maldonado SE, Gysling K, Lagos CF. Molecular Modeling of Structures and Interaction of Human Corticotropin-Releasing Factor (CRF) Binding Protein and CRF Type-2 Receptor. Front Endocrinol (Lausanne) 2018; 9:43. [PMID: 29515519 PMCID: PMC5826306 DOI: 10.3389/fendo.2018.00043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The corticotropin-releasing factor (CRF) system is a key mediator of the stress response and addictive behavior. The CRF system includes four peptides: The CRF system includes four peptides: CRF, urocortins I-III, CRF binding protein (CRF-BP) that binds CRF with high affinity, and two class B G-protein coupled receptors CRF1R and CRF2R. CRF-BP is a secreted protein without significant sequence homology to CRF receptors or to any other known class of protein. Recently, it has been described a potentiation role of CRF-BP over CRF signaling through CRF2R in addictive-related neuronal plasticity and behavior. In addition, it has been described that CRF-BP is capable to physically interact specifically with the α isoform of CRF2R and acts like an escort protein increasing the amount of the receptor in the plasma membrane. At present, there are no available structures for CRF-BP or for full-length CRFR. Knowing and studying the structure of these proteins could be beneficial in order to characterize the CRF-BP/CRF2αR interaction. In this work, we report the modeling of CRF-BP and of full-length CRF2αR and CRF2βR based on the recently solved crystal structures of the transmembrane domains of the human glucagon receptor and human CRF1R, in addition with the resolved N-terminal extracellular domain of CRFRs. These models were further studied using molecular dynamics simulations and protein-protein docking. The results predicted a higher possibility of interaction of CRF-BP with CRF2αR than CRF2βR and yielded the possible residues conforming the interacting interface. Thus, the present study provides a framework for further investigation of the CRF-BP/CRF2αR interaction.
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Affiliation(s)
- Paula G. Slater
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | - Katia Gysling
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- *Correspondence: Katia Gysling, ; Carlos F. Lagos,
| | - Carlos F. Lagos
- Department of Endocrinology, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- *Correspondence: Katia Gysling, ; Carlos F. Lagos,
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Nongmaithem SS, Joglekar CV, Krishnaveni GV, Sahariah SA, Ahmad M, Ramachandran S, Gandhi M, Chopra H, Pandit A, Potdar RD, H D Fall C, Yajnik CS, Chandak GR. GWAS identifies population-specific new regulatory variants in FUT6 associated with plasma B12 concentrations in Indians. Hum Mol Genet 2017; 26:2551-2564. [PMID: 28334792 PMCID: PMC5886186 DOI: 10.1093/hmg/ddx071] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/20/2017] [Indexed: 01/26/2023] Open
Abstract
Vitamin B12 is an important cofactor in one-carbon metabolism whose dysregulation is associated with various clinical conditions. Indians have a high prevalence of B12 deficiency but little is known about the genetic determinants of circulating B12 concentrations in Indians. We performed a genome-wide association study in 1001 healthy participants in the Pune Maternal Nutrition Study (PMNS), replication studies in 3418 individuals from other Indian cohorts and by meta-analysis identified new variants, rs3760775 (P = 1.2 × 10−23) and rs78060698 (P = 8.3 × 10−17) in FUT6 to be associated with circulating B12 concentrations. Although in-silico analysis replicated both variants in Europeans, differences in the effect allele frequency, effect size and the linkage disequilibrium structure of credible set variants with the reported variants suggest population-specific characteristics in this region. We replicated previously reported variants rs602662, rs601338 in FUT2, rs3760776, rs708686 in FUT6, rs34324219 in TCN1 (all P < 5 × 10−8), rs1131603 in TCN2 (P = 3.4 × 10−5), rs12780845 in CUBN (P = 3.0 × 10−3) and rs2270655 in MMAA (P = 2.0 × 10−3). Circulating B12 concentrations in the PMNS and Parthenon study showed a significant decline with increasing age (P < 0.001), however, the genetic contribution to B12 concentrations remained constant. Luciferase reporter and electrophoretic-mobility shift assay for the FUT6 variant rs78060698 using HepG2 cell line demonstrated strong allele-specific promoter and enhancer activity and differential binding of HNF4α, a key regulator of expression of various fucosyltransferases. Hence, the rs78060698 variant, through regulation of fucosylation may control intestinal host-microbial interaction which could influence B12 concentrations. Our results suggest that in addition to established genetic variants, population-specific variants are important in determining plasma B12 concentrations.
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Affiliation(s)
- Suraj S Nongmaithem
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500 007, India
| | - Charudatta V Joglekar
- Diabetes Unit, King Edward Memorial Hospital and Research Centre, Rasta Peth, Pune, Maharashtra 411 011, India
| | - Ghattu V Krishnaveni
- Epidemiology Research Unit, CSI Holdsworth Memorial Hospital, Mysore, Karnataka 570 021, India
| | - Sirazul A Sahariah
- Research Department, Centre for the Study of Social Change, Mumbai, Maharashtra 400 051, India
| | - Meraj Ahmad
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500 007, India
| | - Swetha Ramachandran
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500 007, India
| | - Meera Gandhi
- Research Department, Centre for the Study of Social Change, Mumbai, Maharashtra 400 051, India
| | - Harsha Chopra
- Research Department, Centre for the Study of Social Change, Mumbai, Maharashtra 400 051, India
| | - Anand Pandit
- Department of Pediatrics, King Edward Memorial Hospital and Research Centre, Rasta Peth, Pune, Maharashtra 411 011, India
| | - Ramesh D Potdar
- Research Department, Centre for the Study of Social Change, Mumbai, Maharashtra 400 051, India
| | - Caroline H D Fall
- Research Department, Centre for the Study of Social Change, Mumbai, Maharashtra 400 051, India.,MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Chittaranjan S Yajnik
- Diabetes Unit, King Edward Memorial Hospital and Research Centre, Rasta Peth, Pune, Maharashtra 411 011, India
| | - Giriraj R Chandak
- Genomic Research on Complex Diseases (GRC Group), CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana 500 007, India.,Human Genetics Unit, Genome Institute of Singapore, Biopolis, 138 672, Singapore
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36
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Mutti E, Hunger M, Fedosov S, Nexo E, Kräutler B. Organometallic DNA-B 12 Conjugates as Potential Oligonucleotide Vectors: Synthesis and Structural and Binding Studies with Human Cobalamin-Transport Proteins. Chembiochem 2017; 18:2280-2291. [PMID: 28881087 DOI: 10.1002/cbic.201700472] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Indexed: 12/14/2022]
Abstract
The synthesis and structural characterization of Co-(dN)25 -Cbl (Cbl: cobalamin; dN: deoxynucleotide) and Co-(dN)39 -Cbl, which are organometallic DNA-B12 conjugates with single DNA strands consisting of 25 and 39 deoxynucleotides, respectively, and binding studies of these two DNA-Cbl conjugates to three homologous human Cbl transporting proteins, transcobalamin (TC), intrinsic factor (IF), and haptocorrin (HC), are reported. This investigation tests the suitability of such DNA-Cbls for the task of eventual in vivo oligonucleotide delivery. The binding of DNA-Cbl to TC, IF, and HC was investigated in competition with either a fluorescent Cbl derivative and Co-(dN)25 -Cbl, or radiolabeled vitamin B12 (57 Co-CNCbl) and Co-(dN)25 -Cbl or Co-(dN)39 -Cbl. Binding of the new DNA-Cbl conjugates was fast and tight with TC, but poorer with HC and IF, which extends a similar original finding with the simpler DNA-Cbl, Co-(dN)18 -Cbl. The contrasting affinities of TC versus IF and HC for the DNA-Cbl conjugates are rationalized herein by a stepwise mechanism of Cbl binding. Critical contributions to overall affinity result from gradual conformational adaptations of the Cbl-binding proteins to the DNA-Cbl, which is first bound to the respective β domains. This transition is fast with TC, but slow with IF and HC, with which weaker binding results. The invariably tight interaction of the DNA-Cbl conjugates with TC makes the Cbl moiety a potential natural vector for the specific delivery of oligonucleotide loads from the blood into cells.
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Affiliation(s)
- Elena Mutti
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Miriam Hunger
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Sergey Fedosov
- Department of Molecular Biology and Genetics, Aarhus University, Science Park Gustav WiedsVej 10C, 8000, Aarhus C, Denmark
| | - Ebba Nexo
- Department of Clinical Biochemistry, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Bernhard Kräutler
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
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37
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Nielsen R, Christensen EI, Birn H. Megalin and cubilin in proximal tubule protein reabsorption: from experimental models to human disease. Kidney Int 2017; 89:58-67. [PMID: 26759048 DOI: 10.1016/j.kint.2015.11.007] [Citation(s) in RCA: 313] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 01/19/2023]
Abstract
Proximal tubule protein uptake is mediated by 2 receptors, megalin and cubilin. These receptors rescue a variety of filtered ligands, including biomarkers, essential vitamins, and hormones. Receptor gene knockout animal models have identified important functions of the receptors and have established their essential role in modulating urinary protein excretion. Rare genetic syndromes associated with dysfunction of these receptors have been identified and characterized, providing additional information on the importance of these receptors in humans. Using various disease models in combination with receptor gene knockout, the implications of receptor dysfunction in acute and chronic kidney injury have been explored and have pointed to potential new roles of these receptors. Based on data from animal models, this paper will review current knowledge on proximal tubule endocytic receptor function and regulation, and their role in renal development, protein reabsorption, albumin uptake, and normal renal physiology. These findings have implications for the pathophysiology and diagnosis of proteinuric renal diseases. We will examine the limitations of the different models and compare the findings to phenotypic observations in inherited human disorders associated with receptor dysfunction. Furthermore, evidence from receptor knockout mouse models as well as human observations suggesting a role of protein receptors for renal disease will be discussed in light of conditions such as chronic kidney disease, diabetes, and hypertension.
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Affiliation(s)
- Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Henrik Birn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark.
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38
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Pan C, Weng J, Wang W. Conformational Dynamics and Protein-Substrate Interaction of ABC Transporter BtuCD at the Occluded State Revealed by Molecular Dynamics Simulations. Biochemistry 2016; 55:6897-6907. [PMID: 27951660 DOI: 10.1021/acs.biochem.6b00386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ATP-binding cassette (ABC) transporters are ubiquitous in all three kingdoms of life and are implicated in many clinically relevant physiological processes. They couple the energy released by ATP hydrolysis to facilitate substrate translocation across cell membranes. The crystal structures of type II ABC importers have revealed their unique transmembrane domain architecture consisting of 10 transmembrane helices and their structurally conserved nucleotide-binding domains among all ABC transporters. However, molecular details of the interactions between the importers and their substrate remain largely elusive. Taking vitamin B12 importer BtuCD as an exemplar of type II importers, we investigated the dynamics of its occluded state and the detailed protein-substrate interactions using molecular dynamics simulation. Our trajectories show that the importer accommodates the substrate through a nonspecific binding mode as the substrate undergoes evident vertical and tilt motions inside the translocation cavity. Extensive hydrogen bond and hydrophobic interactions were observed between the substrate and the importer; however, most of these interactions are weak, with <38% occurrence. The presence of substrate leads to enlargement of the translocation cavity, especially at its cytoplasmic end, which may activate cytoplasmic regions and probably facilitate the transportation. The perturbations caused by periplasmic binding protein and nucleotides were also investigated. The study provides deeper insight into the translocation mechanism of BtuCD.
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Affiliation(s)
- Chao Pan
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
| | - Jingwei Weng
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
| | - Wenning Wang
- Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, and Institutes of Biomedical Sciences, Fudan University , Shanghai, P. R. China
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39
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Lewandowski SA, Fredriksson L, Lawrence DA, Eriksson U. Pharmacological targeting of the PDGF-CC signaling pathway for blood-brain barrier restoration in neurological disorders. Pharmacol Ther 2016; 167:108-119. [PMID: 27524729 PMCID: PMC5341142 DOI: 10.1016/j.pharmthera.2016.07.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/25/2016] [Indexed: 12/12/2022]
Abstract
Neurological disorders account for a majority of non-malignant disability in humans and are often associated with dysfunction of the blood-brain barrier (BBB). Recent evidence shows that despite apparent variation in the origin of neural damage, the central nervous system has a common injury response mechanism involving platelet-derived growth factor (PDGF)-CC activation in the neurovascular unit and subsequent dysfunction of BBB integrity. Inhibition of PDGF-CC signaling with imatinib in mice has been shown to prevent BBB dysfunction and have neuroprotective effects in acute damage conditions, including traumatic brain injury, seizures or stroke, as well as in neurodegenerative diseases that develop over time, including multiple sclerosis and amyotrophic lateral sclerosis. Stroke and traumatic injuries are major risk factors for age-associated neurodegenerative disorders and we speculate that restoring BBB properties through PDGF-CC inhibition might provide a common therapeutic opportunity for treatment of both acute and progressive neuropathology in humans. In this review we will summarize what is known about the role of PDGF-CC in neurovascular signaling events and the variety of seemingly different neuropathologies it is involved in. We will also discuss the pharmacological means of therapeutic interventions for anti-PDGF-CC therapy and ongoing clinical trials. In summary: inhibition of PDGF-CC signaling can be protective for immediate injury and decrease the long-term neurodegenerative consequences.
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Affiliation(s)
- Sebastian A Lewandowski
- Tissue Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden.
| | - Linda Fredriksson
- Vascular Biology Groups, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden; Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, 7301 Medical Science Research Building III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0644, USA
| | - Daniel A Lawrence
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, 7301 Medical Science Research Building III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0644, USA
| | - Ulf Eriksson
- Tissue Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden.
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40
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Structural basis of transcobalamin recognition by human CD320 receptor. Nat Commun 2016; 7:12100. [PMID: 27411955 PMCID: PMC4947154 DOI: 10.1038/ncomms12100] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/27/2016] [Indexed: 12/20/2022] Open
Abstract
Cellular uptake of vitamin B12 (cobalamin) requires capture of transcobalamin (TC) from the plasma by CD320, a ubiquitous cell surface receptor of the LDLR family. Here we present the crystal structure of human holo-TC in complex with the extracellular domain of CD320, visualizing the structural basis of the TC-CD320 interaction. The observed interaction chemistry can rationalize the high affinity of CD320 for TC and lack of haptocorrin binding. The in vitro affinity and complex stability of TC-CD320 were quantitated using a solid-phase binding assay and thermostability analysis. Stable complexes with TC were also observed for the disease-causing CD320ΔE88 mutant and for the isolated LDLR-A2 domain. We also determined the structure of the TC-CD320ΔE88 complex, which revealed only minor changes compared with the wild-type complex. Finally, we demonstrate significantly reduced in vitro affinity of TC for CD320 at low pH, recapitulating the proposed ligand release during the endocytic pathway. Cellular uptake of vitamin B12 (cobalamin) requires the binding of holo-transcobalamin (TC) from plasma by CD320. Here, the authors report the structure of a complex between CD320 and TC loaded with cyanocobalamin, alongside additional functional analysis.
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41
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Verma A, Sharma S, Gupta PK, Singh A, Teja BV, Dwivedi P, Gupta GK, Trivedi R, Mishra PR. Vitamin B12 functionalized layer by layer calcium phosphate nanoparticles: A mucoadhesive and pH responsive carrier for improved oral delivery of insulin. Acta Biomater 2016; 31:288-300. [PMID: 26685755 DOI: 10.1016/j.actbio.2015.12.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 12/07/2015] [Accepted: 12/10/2015] [Indexed: 12/21/2022]
Abstract
The present study investigates the potential of layer by layer coated calcium phosphate nanoparticles - for oral delivery of insulin where Vitamin B12 grafted chitosan and sodium alginate have been used as cationic and anionic polyelectrolyte respectively. The major emphasis has been given on the role Vitamin B12 conjugated chitosan as cationic polyelectrolyte (VitB12-Chi) in the delivery system. VitB12-Chi conjugate was prepared by carbodiimide reaction. The formulated VirB12-Chi-CPNPs were tested for in vitro and in vivo efficacy studies carried out in Caco-2 monolayers and diabetic rats. VitB12-Chi-CPNPs with particle size <250nm and zeta potential+32.56(±2.34) exhibited pH responsive insulin release at simulated gastric fluid and simulated intestinal fluid. Fluorescence microscopy and flow cytometry studies revealed higher uptake of VitB12-Chi-CPNPs in Caco-2 monolayer in comparison to Chi-CPNPs. Further reduction in TEER supported paracellular transport of insulin because of opening of tight epithelial junctions. In vivo intestinal uptake of FITC tagged Vit-B12-Chi-CPNPs from different intestinal segments supported paracellular and receptor mediated uptake of VitB12-Chi-CPNPs. Plasma insulin and blood glucose levels were measured in diabetic rats and showed about four fold increases in insulin bioavailability and sustained hypoglycemic effects up to 12h of administration with VitB12-Chi-CPNPs in comparison to Chi-CPNPs. Results of the study revealed the potential of layer by layer nanoparticles for oral insulin delivery. The study also specifically highlighted the role of VitB12 as a pH sensitive and targeting ligand which significantly participated in enhancing insulin oral bioavailability. STATEMENT OF SIGNIFICANCE Oral delivery of insulin is always the most desirable approach for diabetic patients however it's also the most challenging in respect to formulation development due to harsh gastrointestinal conditions. Several groups have been working from decades for oral delivery of insulin. However the beauty of this prototype formulation is that it exhibits the pH responsive behavior in natural condition of gastrointestinal tract. It resists the release of insulin at gastric condition however stimulate the release at intestinal conditions. Apart from pH responsive behavior it utilizes multiple pathways to improve the overall bioavailability of insulin including paracellular transport and receptor mediated endocytosis.
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43
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Zelder F. Recent trends in the development of vitamin B12 derivatives for medicinal applications. Chem Commun (Camb) 2015; 51:14004-17. [PMID: 26287029 DOI: 10.1039/c5cc04843e] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This Feature Article highlights recent developments in the field of vitamin B12 derivatives for medicinal applications. The following topics are emphasized: (1) the development of aquacorrinoids for cyanide detection and detoxification, (2) the use of vitamin B12 conjugates and (3) antivitamins B12 for therapy and diagnosis, and (4) the design of corrinoids as activators of soluble guanylyl cyclase (sGC).
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Affiliation(s)
- Felix Zelder
- Department of Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
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A novel chemical footprinting approach identifies critical lysine residues involved in the binding of receptor-associated protein to cluster II of LDL receptor-related protein. Biochem J 2015; 468:65-72. [PMID: 25728577 DOI: 10.1042/bj20140977] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Tandem mass tags (TMTs) were utilized in a novel chemical footprinting approach to identify lysine residues that mediate the interaction of receptor-associated protein (RAP) with cluster II of LDL (low-density lipoprotein) receptor (LDLR)-related protein (LRP). The isolated RAP D3 domain was modified with TMT-126 and the D3 domain-cluster II complex with TMT-127. Nano-LC-MS analysis revealed reduced modification with TMT-127 of peptides including Lys(256), Lys(270) and Lys(305)-Lys(306) suggesting that these residues contribute to cluster II binding. This agrees with previous findings that Lys(256) and Lys(270) are critical for binding cluster II sub-domains [Fisher, Beglova and Blacklow (2006) Mol. Cell 22, 277-283]. Cluster II-binding studies utilizing D3 domain variants K(256)A, K(305)A and K(306)A now showed that Lys(306) contributes to cluster II binding as well. For full-length RAP, we observed that peptides including Lys(60), Lys(191), Lys(256), Lys(270) and Lys(305)-Lys(306) exhibited reduced modification with TMT in the RAP-cluster II complex. Notably, Lys(60) has previously been implicated to mediate D1 domain interaction with cluster II. Our results suggest that also Lys(191) of the D2 domain contributes to cluster II binding. Binding studies employing the RAP variants K(191)A, K(256)A, K(305)A and K(306)A, however, revealed a modest reduction in cluster II binding for the K(256)A variant only. This suggests that the other lysine residues can compensate for the absence of a single lysine residue for effective complex assembly. Collectively, novel insight has been obtained into the contribution of lysine residues of RAP to cluster II binding. In addition, we propose that TMTs can be utilized to identify lysine residues critical for protein complex formation.
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Abstract
B12 -antimetabolites are compounds that counteract the physiological effects of vitamin B12 and related natural cobalamins. Presented here is a structure- and reactivity-based concept of the specific 'antivitamins B12 ': it refers to analogues of vitamin B12 that display high structural similarity to the vitamin and are 'locked chemically' to prevent their metabolic conversion into the crucial organometallic B12 -cofactors. Application of antivitamins B12 to healthy laboratory animals is, thus, expected to induce symptoms of B12 -deficiency. Antivitamins B12 may, hence, be helpful in elucidating still largely puzzling pathophysiological phenomena associated with B12 -deficiency, and also in recognizing physiological roles of B12 that probably still remain to be discovered.
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Affiliation(s)
- Bernhard Kräutler
- Institute of Organic Chemistry & Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80/82, 6020 Innsbruck (Austria).
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Kjaer TR, Le LTM, Pedersen JS, Sander B, Golas MM, Jensenius JC, Andersen GR, Thiel S. Structural insights into the initiating complex of the lectin pathway of complement activation. Structure 2015; 23:342-51. [PMID: 25579818 DOI: 10.1016/j.str.2014.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/18/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
Abstract
The proteolytic cascade of the complement system is initiated when pattern-recognition molecules (PRMs) bind to ligands, resulting in the activation of associated proteases. In the lectin pathway of complement, the complex of mannan-binding lectin (MBL) and MBL-associated serine protease-1 (MASP-1) initiates the pathway by activating a second protease, MASP-2. Here we present a structural study of a PRM/MASP complex and derive the overall architecture of the 450 kDa MBL/MASP-1 complex using small-angle X-ray scattering and electron microscopy. The serine protease (SP) domains from the zymogen MASP-1 dimer protrude from the cone-like MBL tetramer and are separated by at least 20 nm. This suggests that intracomplex activation within a single MASP-1 dimer is unlikely and instead supports intercomplex activation, whereby the MASP SP domains are accessible to nearby PRM-bound MASPs. This activation mechanism differs fundamentally from the intracomplex initiation models previously proposed for both the lectin and the classical pathway.
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Affiliation(s)
- Troels R Kjaer
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Le T M Le
- Department of Clinical Medicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Bjoern Sander
- Department of Clinical Medicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark; Center for Stochastic Geometry and Advanced Bioimaging (CSGB), Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark; Center for Stochastic Geometry and Advanced Bioimaging (CSGB), Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Jens Christian Jensenius
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Bartholins Allé 6 and Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark.
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Structural basis for trypanosomal haem acquisition and susceptibility to the host innate immune system. Nat Commun 2014; 5:5487. [DOI: 10.1038/ncomms6487] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/06/2014] [Indexed: 11/08/2022] Open
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Jensen LL, Andersen RK, Hager H, Madsen M. Lack of megalin expression in adult human terminal ileum suggests megalin-independent cubilin/amnionless activity during vitamin B12 absorption. Physiol Rep 2014; 2:2/7/e12086. [PMID: 25052491 PMCID: PMC4187553 DOI: 10.14814/phy2.12086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cubilin plays an essential role in terminal ileum and renal proximal tubules during absorption of vitamin B12 and ligands from the glomerular ultrafiltrate. Cubilin is coexpressed with amnionless, and cubilin and amnionless are mutually dependent on each other for correct processing to the plasma membrane upon synthesis. Patients with defects in either protein suffer from vitamin B12‐malabsorption and in some cases proteinuria. Cubilin lacks a transmembrane region and signals for endocytosis and is dependent on a transmembrane coreceptor during internalization. Amnionless has been shown to be able to mediate internalization of cubilin in a cell‐based model system. Cubilin has additionally been suggested to function together with megalin, and a recent study of megalin‐deficient patients indicates that uptake of cubilin ligands in the kidney is critically dependent on megalin. To further investigate the potential role of amnionless and megalin in relation to cubilin function in terminal ileum and vitamin B12 uptake, we initiated a study of CUBN/cubilin, AMN/amnionless, and LRP2/megalin expression in adult human terminal ileum. Our study is the first to reveal the expression pattern of cubilin, amnionless, and megalin in adult human terminal ileum, where cubilin and amnionless localize to the epithelial cells. Surprisingly, we did not detect any megalin protein in adult terminal ileum and consistently, only extremely low amounts of LRP2 mRNA. Our data therefore advocate that cubilin and amnionless act independently of megalin in adult terminal ileum and that the cubilin‐megalin interdependency accordingly should be considered as tissue and ligand specific. e12086 Studies of human terminal ileum samples demonstrate lack of LRP2/megalin expression in adult terminal ileum and point to a megalin‐independent cubilin‐amnionless‐driven uptake mechanism for vitamin B12.
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Affiliation(s)
- Louise L Jensen
- Department of Biomedicine, University of Aarhus, 8000 Aarhus C., Denmark
| | - Rikke K Andersen
- Department of Biomedicine, University of Aarhus, 8000 Aarhus C., Denmark
| | - Henrik Hager
- Department of Pathology, Aarhus University Hospital, 8000 Aarhus C., Denmark
| | - Mette Madsen
- Department of Biomedicine, University of Aarhus, 8000 Aarhus C., Denmark
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How calcium makes endocytic receptors attractive. Trends Biochem Sci 2014; 39:82-90. [DOI: 10.1016/j.tibs.2013.12.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/28/2013] [Accepted: 12/06/2013] [Indexed: 12/21/2022]
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Kjaer TR, Thiel S, Andersen GR. Toward a structure-based comprehension of the lectin pathway of complement. Mol Immunol 2013; 56:222-31. [DOI: 10.1016/j.molimm.2013.05.220] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/09/2013] [Indexed: 01/19/2023]
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