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Previdi A, Dubourg C, Cormier Daire V, Fradin M, Collet C. Novel variant in LRP6 associated with unusual and severe clinical presentation: Case report. Clin Genet 2024; 105:666-670. [PMID: 38385987 DOI: 10.1111/cge.14501] [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: 11/30/2023] [Revised: 01/22/2024] [Accepted: 02/01/2024] [Indexed: 02/23/2024]
Abstract
Low-density lipoprotein receptor-related protein 6 (LRP6) is a co-receptor of the Wnt signaling pathway, which plays an essential role in various biological activities during embryonic and postnatal development. LRP6 is exceptionally associated with rare diseases and always with autosomal dominant inheritance. Here we report a familial phenotype of high bone mass associated with skeletal anomalies and oligodontia but also persistent left superior vena cava, inguinal hernia, hepatic cysts, abnormal posterior fossa and genital malformations. Molecular analysis revealed a novel heterozygous variant, NM_002336.2: c.724T>C, p.(Trp242Arg), in affected individuals. This variant is located in the first β-propellant motif of LRP6, to which sclerostin (SOST) and dickkopf1 (DKK1), two LRP6 co-receptor inhibitors and various Wnt ligands bind. According to the literature and integrating data from structural analysis, this variant distorts the binding of SOST and DKK1, thus leading to overactivation of Wnt signaling pathways involved in osteoblast differentiation. This novel heterozygous variant in LRP6 underlies the role of LRP6 in skeletal and dental disorders as well as, probably, cardiac, cerebral and genital developments.
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Affiliation(s)
- Anaïk Previdi
- UFR de Pharmacie, Université Paris Cité, Paris, France
| | - Christèle Dubourg
- Service de Génétique Moléculaire, CHU Rennes, Hôpital Sud, CLAD Ouest, Rennes, France
- Laboratoire de Biologie Médicale Multisites Seqoia-FMG2025, Paris, France
| | - Valérie Cormier Daire
- Département de Génomique, INSERM UMR1163, Institut Imagine, CHU Necker-Enfants Malades, Paris, France
| | - Mélanie Fradin
- Service de Génétique Clinique, CHU Rennes, Hôpital Sud, CLAD Ouest, Rennes, France
| | - Corinne Collet
- UFR de Pharmacie, Université Paris Cité, Paris, France
- Laboratoire de Biologie Médicale Multisites Seqoia-FMG2025, Paris, France
- Département de Génomique, INSERM UMR1163, Institut Imagine, CHU Necker-Enfants Malades, Paris, France
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2
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Rare Variants in LRP4 Are Associated with Mesiodens, Root Maldevelopment, and Oral Exostoses in Humans. BIOLOGY 2023; 12:biology12020220. [PMID: 36829498 PMCID: PMC9952772 DOI: 10.3390/biology12020220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/23/2023] [Accepted: 01/28/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND Low density lipoprotein receptor-related protein 4 (LRP4; MIM 604270) modulates WNT/β-catenin signaling, through its binding of WNT ligands, and to co-receptors LRP5/6, and WNT inhibitors DKK1, SOSTDC1, and SOST. LRP4 binds to SOSTDC1 and WNT proteins establishing a negative feedback loop between Wnt/β-catenin, Bmp, and Shh signaling during the bud and cap stages of tooth development. Consistent with a critical role for this complex in developing teeth, mice lacking Lrp4 or Sostdc1 have multiple dental anomalies including supernumerary incisors and molars. However, there is limited evidence supporting variants in LRP4 in human dental pathologies. METHODS We clinically, radiographically, and molecularly investigated 94 Thai patients with mesiodens. Lrp4 mutant mice were generated in order to study the effects of aberrant Lrp4 expression in mice. RESULTS Whole exome and Sanger sequencing identified three extremely rare variants (c.4154A>G, p.Asn1385Ser; c.3940G>A, p.Gly1314Ser; and c.448G>A, p.Asp150Asn) in LRP4 in seven patients with mesiodens. Two patients had oral exostoses and two patients had root maldevelopments. Supernumerary incisors were observed in Lrp4 mutant mice. CONCLUSIONS Our study implicates heterozygous genetic variants in LRP4 as contributing factors in the presentation of mesiodens, root maldevelopments, and oral exostoses, possibly as a result of altered WNT/β-catenin-BMP-SHH signaling.
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3
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Craig SEL, Michalski MN, Williams BO. Got WNTS? Insight into bone health from a WNT perspective. Curr Top Dev Biol 2023; 153:327-346. [PMID: 36967199 DOI: 10.1016/bs.ctdb.2023.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
WNT signaling, essential for many aspects of development, is among the most commonly altered pathways associated with human disease. While initially studied in cancer, dysregulation of WNT signaling has been determined to be essential for skeletal development and the maintenance of bone health throughout life. In this review, we discuss the role of Wnt signaling in bone development and disease with a particular focus on two areas. First, we discuss the roles of WNT signaling pathways in skeletal development, with an emphasis on congenital and idiopathic skeletal syndromes and diseases that are associated with genetic variations in WNT signaling components. Next, we cover a topic that has long been an interest of our laboratory, how high and low levels of WNT signaling affects the establishment and maintenance of healthy bone mass. We conclude with a discussion of the status of WNT-based therapeutics in the treatment of skeletal disease.
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Affiliation(s)
- Sonya E L Craig
- Department of Cell Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Megan N Michalski
- Department of Cell Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - Bart O Williams
- Department of Cell Biology, Van Andel Institute, Grand Rapids, MI, United States.
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4
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Kantaputra P, Tripuwabhrut K, Jatooratthawichot P, Adisornkanj P, Hatsadaloi A, Porntrakoolsaree N, Kaewgaya M, Olsen B, Tongsima S, Ngamphiw C, Ketudat Cairns JR. Mutations in the WLS are associated with dental anomalies, torus palatinus, and torus mandibularis. Eur J Orthod 2022; 45:317-323. [DOI: 10.1093/ejo/cjac068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Summary
Background
Canonical and non-canonical WNT signaling are important for odontogenesis. WNT ligand secretion mediator (WLS; MIM611514) is required to transport lipid-modified WNT proteins from the Golgi to the cell membrane, where canonical and non-canonical WNT proteins are released into the extracellular milieu. Biallelic pathogenic variants in WLS are implicated in autosomal recessive Zaki syndrome (ZKS; MIM 619648), the only genetic condition known to be caused by pathogenic variants in WLS.
Objective
To investigate molecular etiology of dental anomalies in 250 patients with or without oral exostoses.
Patients and methods
Clinical and radiographic examination, and whole exome sequencing, were performed in the case of 250 patients with dental anomalies with or without oral exostoses.
Results
Four extremely rare heterozygous missense variants (p.Ile20Thr, p.Met46Leu, p.Ser453Ile and p.Leu516Phe) in WLS were identified in 11 patients with dental anomalies. In five of these patients, a torus palatinus or a torus mandibularis was observed.
Conclusion
We report for the first time the heterozygous WLS variants in patients with dental anomalies. Root maldevelopments in patients with WLS variants supports the role of canonical and non-canonical WNT signaling in root development. We also show that variants in WLS were implicated in torus palatinus and torus mandibularis. In addition, this is the first time that heterozygous carriers of WLS variants were found to manifest phenotypes. WLS variants were likely to have adverse effects on the concentration of WNT ligands delivered to the cell membrane, resulting in aberrant canonical and non-canonical WNT signaling, and subsequent phenotypes.
Limitations of the study
Patient’s positioning during the acquisition of panoramic radiography might have affected the appearance of the tooth structures. If we had all family members of each patient to study co-segregation between genotype and phenotype, it would have strengthened the association of WLS variants and the phenotypes.
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Affiliation(s)
- Piranit Kantaputra
- Center of Excellence in Medical Genetics Research, Chiang Mai University , Chiang Mai , Thailand
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University , Chiang Mai , Thailand
| | - Kanich Tripuwabhrut
- Division of Orthodontics, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University , Chiang Mai , Thailand
| | - Peeranat Jatooratthawichot
- School of Chemistry, Institute of Science, and Center for Biomolecular Structure, Function and Application, Suranaree University of Technology , Nakhon Ratchasima , Thailand
| | - Ploy Adisornkanj
- Center of Excellence in Medical Genetics Research, Chiang Mai University , Chiang Mai , Thailand
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University , Chiang Mai , Thailand
- Dental Department, Sawang Daen Din Crown Prince Hospital , Sakon Nakhon , Thailand
| | | | | | - Massupa Kaewgaya
- Center of Excellence in Medical Genetics Research, Chiang Mai University , Chiang Mai , Thailand
| | - Bjorn Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard University , Boston, MA , USA
| | - Sissades Tongsima
- National Biobank of Thailand, National Science and Technology Development Agency (NSTDA), Thailand Science Park , Pathum Thani , Thailand
| | - Chumpol Ngamphiw
- National Biobank of Thailand, National Science and Technology Development Agency (NSTDA), Thailand Science Park , Pathum Thani , Thailand
| | - James R Ketudat Cairns
- School of Chemistry, Institute of Science, and Center for Biomolecular Structure, Function and Application, Suranaree University of Technology , Nakhon Ratchasima , Thailand
- Laboratory of Biochemistry, Chulabhorn Research Institute , Bangkok , Thailand
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5
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Puente N, Vega AI, Hernandez JL, Fernandez-Luna JL, Riancho JA. An LRP6 mutation (Arg360His) associated with low bone mineral density but not cardiovascular events in a Caucasian family. Osteoporos Int 2022; 33:2445-2448. [PMID: 35840698 PMCID: PMC9568478 DOI: 10.1007/s00198-022-06494-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/04/2022] [Indexed: 11/29/2022]
Abstract
UNLABELLED We present a family with a rare mutation of the LRP6 gene and for the first time provide evidence for its association with low bone mineral density. INTRODUCTION The Wnt pathway plays a critical role in bone homeostasis. Pathogenic variants of the Wnt co-receptor LRP6 have been associated with abnormal skeletal phenotypes or increased risk of cardiovascular events. PATIENT AND METHODS Here we report an index premenopausal patient and her family carrying a rare missense LRP6 pathogenic variant (rs141212743; 0.0002 frequency among Europeans). This variant has been previously associated with metabolic syndrome and atherosclerosis, in the presence of normal bone mineral density. However, the LRP6 variant was associated with low bone mineral density in this family, without evidence for association with serum lipid levels or cardiovascular events. CONCLUSION Thus, this novel association shows that LRP6 pathogenic variants may be involved in some cases of early-onset osteoporosis, but the predominant effect, either skeletal or cardiovascular, may vary depending on the genetic background or other acquired factors.
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Affiliation(s)
- Nuria Puente
- Servicio de Medicina Interna, Hospital UM Valdecilla, Universidad de Cantabria, IDIVAL, Avda Valdecilla sn, 39008, Santander, Spain
| | - Ana I Vega
- Servicio de Genética, Hospital UM Valdecilla, IDIVAL, Santander, Spain
| | - José L Hernandez
- Servicio de Medicina Interna, Hospital UM Valdecilla, Universidad de Cantabria, IDIVAL, Avda Valdecilla sn, 39008, Santander, Spain
| | | | - Jose A Riancho
- Servicio de Medicina Interna, Hospital UM Valdecilla, Universidad de Cantabria, IDIVAL, Avda Valdecilla sn, 39008, Santander, Spain.
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6
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Charoenngam N, Nasr A, Shirvani A, Holick MF. Hereditary Metabolic Bone Diseases: A Review of Pathogenesis, Diagnosis and Management. Genes (Basel) 2022; 13:genes13101880. [PMID: 36292765 PMCID: PMC9601711 DOI: 10.3390/genes13101880] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/03/2022] [Accepted: 10/13/2022] [Indexed: 11/20/2022] Open
Abstract
Hereditary metabolic bone diseases are characterized by genetic abnormalities in skeletal homeostasis and encompass one of the most diverse groups among rare diseases. In this review, we examine 25 selected hereditary metabolic bone diseases and recognized genetic variations of 78 genes that represent each of the three groups, including sclerosing bone disorders, disorders of defective bone mineralization and disorder of bone matrix and cartilage formation. We also review pathophysiology, manifestation and treatment for each disease. Advances in molecular genetics and basic sciences has led to accurate genetic diagnosis and novel effective therapeutic strategies for some diseases. For other diseases, the genetic basis and pathophysiology remain unclear. Further researches are therefore crucial to innovate ways to overcome diagnostic challenges and develop effective treatment options for these orphan diseases.
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Affiliation(s)
- Nipith Charoenngam
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Medicine, Mount Auburn Hospital, Harvard Medical School, Cambridge, MA 02138, USA
- Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Aryan Nasr
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Arash Shirvani
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Michael F. Holick
- Section Endocrinology, Diabetes, Nutrition and Weight Management, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-6139
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7
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Lee Y, Chae W, Kim YJ, Kim JW. Novel LRP6 Mutations Causing Non-Syndromic Oligodontia. J Pers Med 2022; 12:jpm12091401. [PMID: 36143186 PMCID: PMC9504909 DOI: 10.3390/jpm12091401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 11/26/2022] Open
Abstract
The process of tooth formation is a series of reciprocal interactions between the ectoderm and mesoderm, and it is believed that many genetic factors are involved in this complex process. More than a dozen genes have been identified in non-syndromic tooth agenesis; however, the genetic etiology underlying tooth agenesis is not fully understood yet. In this study, we identified two novel LRP6 mutations in two non-syndromic oligodontia families. Both probands had 16 and 17 missing teeth in their permanent dentition. Mutational analysis identified a de novo frameshift mutation by a 1-bp insertion in exon 9 (NM_002336.2: c.1870dupA, p.(Met624Asnfs*29)) and a splicing donor site mutation in intron 8 (c.1762+2T>C). An in vitro splicing assay confirmed the deletion of exon 8, and the deletion would result in a frameshift. Due to the premature termination codons introduced by the frameshift, both mutant transcripts would be degraded by nonsense-mediated mRNA decay, resulting in haploinsufficiency.
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Affiliation(s)
- Yejin Lee
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea
| | - Wonseon Chae
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea
| | - Youn Jung Kim
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea
| | - Jung-Wook Kim
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea
- Department of Molecular Genetics & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea
- Correspondence:
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8
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Kantaputra P, Jatooratthawichot P, Jintakanon K, Intachai W, Pradermdutsadeeporn P, Adisornkanj P, Tongsima S, Ngamphiw C, Olsen B, Tucker AS, Cairns JRK. Mutations in LRP6 highlight the role of WNT signalling in oral exostoses and dental anomalies. Arch Oral Biol 2022; 142:105514. [DOI: 10.1016/j.archoralbio.2022.105514] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/15/2022] [Accepted: 07/28/2022] [Indexed: 02/07/2023]
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9
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Chen J, Cuevas P, Dworan J, Dawid I, Turkkahraman H, Tran K, Delgado-Calle J, Bellido T, Gorski J, Liu B, Brunski J, Helms J. Wnt/β-catenin Signaling Controls Maxillofacial Hyperostosis. J Dent Res 2022; 101:793-801. [PMID: 35114849 PMCID: PMC10850863 DOI: 10.1177/00220345211067705] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The roles of Wnt/β-catenin signaling in regulating the morphology and microstructure of craniomaxillofacial (CMF) bones was explored using mice carrying a constitutively active form of β-catenin in activating Dmp1-expressing cells (e.g., daβcatOt mice). By postnatal day 24, daβcatOt mice exhibited midfacial truncations coupled with maxillary and mandibular hyperostosis that progressively worsened with age. Mechanistic insights into the basis for the hyperostotic facial phenotype were gained through molecular and cellular analyses, which revealed that constitutively activated β-catenin in Dmp1-expressing cells resulted in an increase in osteoblast number and an increased rate of mineral apposition. An increase in osteoblasts was accompanied by an increase in osteocytes, but they failed to mature. The resulting CMF bone matrix also had an abundance of osteoid, and in locations where compact lamellar bone typically forms, it was replaced by porous, woven bone. The hyperostotic facial phenotype was progressive. These findings identify for the first time a ligand-independent positive feedback loop whereby unrestrained Wnt/β-catenin signaling results in a CMF phenotype of progressive hyperostosis combined with architecturally abnormal, poorly mineralized matrix that is reminiscent of craniotubular disorders in humans.
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Affiliation(s)
- J. Chen
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P.L. Cuevas
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.S. Dworan
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
- Medical University of Vienna, Department of Anatomy, Center for Anatomy and Cell Biology, Vienna, Austria
| | - I. Dawid
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - H. Turkkahraman
- Indiana University School of Dentistry, Department of Orthodontics & Oral Facial Genetics, Indianapolis, IN, USA
| | - K. Tran
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J. Delgado-Calle
- Department of Physiology & Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - T. Bellido
- Department of Physiology & Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - J.P. Gorski
- Department of Oral and Craniofacial Sciences, School of Dentistry, and Center of Excellence in Mineralized Tissue Research, University of Missouri–Kansas City, Kansas City, MO, USA
| | - B. Liu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.B. Brunski
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - J.A. Helms
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Stanford University School of Medicine, Palo Alto, CA, USA
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10
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Kantaputra P, Guven Y, Tripuwabhrut K, Adisornkanj P, Hatsadaloi A, Kaewgahya M, Olsen B, Ngamphiw C, Jatooratthawichot P, Tongsima S, Ketudat Cairns JR. Mutations in LRP5 and BMP4 are associated with mesiodens, tooth agenesis, root malformation, and oral exostoses. Clin Genet 2022; 102:333-338. [PMID: 35754005 DOI: 10.1111/cge.14183] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/29/2022]
Abstract
WNT/β-catenin and BMP signaling pathways play important roles in the process of tooth development. Dysregulation of WNT/β-catenin and BMP signaling is implicated in a number of human malformations, including dental anomalies. Whole exome and Sanger sequencing identified seven patients with LRP5 mutations (p.Asn1121Asp, p.Asp856Asn, p.Val1433Met, and p.Val1245Met) and six patients with BMP4 mutations (p.Asn150Lys, p.Gly168Arg, p.Arg269Gln, and p.Ala42Glu). All patients were affected with isolated dental anomalies (dental anomalies with no other structural defects), including mesiodens, tooth agenesis, unseparated roots, narrow roots, shortened and tapered roots, and taurodontism. Five and a patients with LRP5 and BMP4 mutations had oral exostoses, respectively. Protein models of LRP5 mutations indicate the possible functional effects of the mutations. Here we report for the first time that mutations in LRP5 are associated with dental anomalies. LRP5 appears to be the first gene related to pathogenesis of mesiodens. We also show for the first time that in addition to tooth agenesis, mutations in BMP4 are also implicated in root maldevelopment and torus mandibularis. Sharing the phenotypes of the patients with LRP5 and BMP4 mutations, which include root maldevelopment, tooth agenesis, and torus mandibularis, implicates cross-talks between WNT/β-catenin and BMP signaling pathways, especially during root development.
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Affiliation(s)
- Piranit Kantaputra
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Division of Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Yeliz Guven
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Kanich Tripuwabhrut
- Division of Orthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Ploy Adisornkanj
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Division of Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.,Dental Department, Sawang Daen Din Crown Prince Hospital, Sakon Nakhon, Thailand
| | | | - Massupa Kaewgahya
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - Bjorn Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Harvard University, Boston, MA, USA
| | - Chumpol Ngamphiw
- National Biobank of Thailand, National Science and Technology Development Agency, Thailand Science Park, Pathum Thani, Thailand
| | - Peeranat Jatooratthawichot
- School of Chemistry, Institute of Science, and Center for Biomolecular Structure, Function and Application, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Sissades Tongsima
- National Biobank of Thailand, National Science and Technology Development Agency, Thailand Science Park, Pathum Thani, Thailand
| | - James R Ketudat Cairns
- School of Chemistry, Institute of Science, and Center for Biomolecular Structure, Function and Application, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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11
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Ruan S, Huang Y, He M, Gao H. Advanced Biomaterials for Cell-Specific Modulation and Restore of Cancer Immunotherapy. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200027. [PMID: 35343112 PMCID: PMC9165523 DOI: 10.1002/advs.202200027] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/18/2022] [Indexed: 05/09/2023]
Abstract
The past decade has witnessed the explosive development of cancer immunotherapies. Nevertheless, low immunogenicity, limited specificity, poor delivery efficiency, and off-target side effects remain to be the major limitations for broad implementation of cancer immunotherapies to patient bedside. Encouragingly, advanced biomaterials offering cell-specific modulation of immunological cues bring new solutions for improving the therapeutic efficacy while relieving side effect risks. In this review, focus is given on how functional biomaterials can enable cell-specific modulation of cancer immunotherapy within the cancer-immune cycle, with particular emphasis on antigen-presenting cells (APCs), T cells, and tumor microenvironment (TME)-resident cells. By reviewing the current progress in biomaterial-based cancer immunotherapy, here the aim is to provide a better understanding of biomaterials' role in targeting modulation of antitumor immunity step-by-step and guidelines for rationally developing targeting biomaterials for more personalized cancer immunotherapy. Moreover, the current challenge and future perspective regarding the potential application and clinical translation will also be discussed.
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Affiliation(s)
- Shaobo Ruan
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081China
| | - Yuanyu Huang
- Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081China
| | - Mei He
- College of PharmacyUniversity of FloridaGainesvilleFL32610USA
| | - Huile Gao
- West China School of PharmacySichuan UniversityChengdu610041China
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12
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Martínez‐Gil N, Ovejero D, Garcia‐Giralt N, Bruque CD, Mellibovsky L, Nogués X, Rabionet R, Grinberg D, Balcells S. Genetic analysis in a familial case with high bone mineral density suggests additive effects at two
loci. JBMR Plus 2022; 6:e10602. [PMID: 35434450 PMCID: PMC9009133 DOI: 10.1002/jbm4.10602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 12/24/2021] [Accepted: 01/16/2022] [Indexed: 11/21/2022] Open
Abstract
Osteoporosis is the most common bone disease, characterized by a low bone mineral density (BMD) and increased risk of fracture. At the other end of the BMD spectrum, some individuals present strong, fracture‐resistant, bones. Both osteoporosis and high BMD are heritable and their genetic architecture encompasses polygenic inheritance of common variants and some cases of monogenic highly penetrant variants in causal genes. We have investigated the genetics of high BMD in a family segregating this trait in an apparently Mendelian dominant pattern. We searched for rare causal variants by whole‐exome sequencing in three affected and three nonaffected family members. Using this approach, we have identified 38 rare coding variants present in the proband and absent in the three individuals with normal BMD. Although we have found four variants shared by the three affected members of the family, we have not been able to relate any of these to the high‐BMD phenotype. In contrast, we have identified missense variants in two genes, VAV3 and ADGRE5, each shared by two of out of three affected members, whose loss of function fits with the phenotype of the family. In particular, the proband, a woman displaying the highest BMD (sum Z‐score = 7), carries both variants, whereas the other two affected members carry one each. VAV3 encodes a guanine‐nucleotide‐exchange factor with an important role in osteoclast activation and function. Although no previous cases of VAV3 mutations have been reported in humans, Vav3 knockout (KO) mice display dense bones, similarly to the high‐BMD phenotype present in our family. The ADGRE5 gene encodes an adhesion G protein‐coupled receptor expressed in osteoclasts whose KO mouse displays increased trabecular bone volume. Combined, these mouse and human data highlight VAV3 and ADGRE5 as novel putative high‐BMD genes with additive effects, and potential therapeutic targets for osteoporosis. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Núria Martínez‐Gil
- Department of Genetics, Microbiology and Statistics Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD Barcelona Spain
| | - Diana Ovejero
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII Barcelona Spain
| | - Natalia Garcia‐Giralt
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII Barcelona Spain
| | - Carlos David Bruque
- Unidad de Conocimiento Traslacional Hospitalaria Patagónica, Hospital de Alta Complejidad SAMIC El Calafate Santa Cruz Argentina
| | - Leonardo Mellibovsky
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII Barcelona Spain
| | - Xavier Nogués
- Musculoskeletal Research Group, IMIM (Hospital del Mar Medical Research Institute), Centro de Investigación Biomédica en Red en Fragilidad y Envejecimiento Saludable (CIBERFES), ISCIII Barcelona Spain
| | - Raquel Rabionet
- Department of Genetics, Microbiology and Statistics Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD Barcelona Spain
| | - Daniel Grinberg
- Department of Genetics, Microbiology and Statistics Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD Barcelona Spain
| | - Susanna Balcells
- Department of Genetics, Microbiology and Statistics Faculty of Biology, Universitat de Barcelona, CIBERER, IBUB, IRSJD Barcelona Spain
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13
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St-Arnaud R, Pellicelli M, Ismail M, Arabian A, Jafarov T, Zhou CJ. NACA and LRP6 Are Part of a Common Genetic Pathway Necessary for Full Anabolic Response to Intermittent PTH. Int J Mol Sci 2022; 23:ijms23020940. [PMID: 35055125 PMCID: PMC8780913 DOI: 10.3390/ijms23020940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 11/28/2022] Open
Abstract
PTH induces phosphorylation of the transcriptional coregulator NACA on serine 99 through Gαs and PKA. This leads to nuclear translocation of NACA and expression of the target gene Lrp6, encoding a coreceptor of the PTH receptor (PTH1R) necessary for full anabolic response to intermittent PTH (iPTH) treatment. We hypothesized that maintaining enough functional PTH1R/LRP6 coreceptor complexes at the plasma membrane through NACA-dependent Lrp6 transcription is important to ensure maximal response to iPTH. To test this model, we generated compound heterozygous mice in which one allele each of Naca and Lrp6 is inactivated in osteoblasts and osteocytes, using a knock-in strain with a Naca99 Ser-to-Ala mutation and an Lrp6 floxed strain (test genotype: Naca99S/A; Lrp6+/fl;OCN-Cre). Four-month-old females were injected with vehicle or 100 μg/kg PTH(1-34) once daily, 5 days a week for 4 weeks. Control mice showed significant increases in vertebral trabecular bone mass and biomechanical properties that were abolished in compound heterozygotes. Lrp6 expression was reduced in compound heterozygotes vs. controls. The iPTH treatment increased Alpl and Col1a1 mRNA levels in the control but not in the test group. These results confirm that NACA and LRP6 form part of a common genetic pathway that is necessary for the full anabolic effect of iPTH.
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Affiliation(s)
- René St-Arnaud
- Research Centre, Shriners Hospital for Children—Canada, Montreal, QC H4A 0A9, Canada; (M.P.); (M.I.); (A.A.); (T.J.)
- Department of Surgery, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 1A4, Canada
- Department of Human Genetics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 0C7, Canada
- Department of Medicine, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 1A1, Canada
- Correspondence: ; Tel.: +1-514-282-7155; Fax: +1-514-842-5581
| | - Martin Pellicelli
- Research Centre, Shriners Hospital for Children—Canada, Montreal, QC H4A 0A9, Canada; (M.P.); (M.I.); (A.A.); (T.J.)
| | - Mahmoud Ismail
- Research Centre, Shriners Hospital for Children—Canada, Montreal, QC H4A 0A9, Canada; (M.P.); (M.I.); (A.A.); (T.J.)
| | - Alice Arabian
- Research Centre, Shriners Hospital for Children—Canada, Montreal, QC H4A 0A9, Canada; (M.P.); (M.I.); (A.A.); (T.J.)
| | - Toghrul Jafarov
- Research Centre, Shriners Hospital for Children—Canada, Montreal, QC H4A 0A9, Canada; (M.P.); (M.I.); (A.A.); (T.J.)
| | - Chengji J. Zhou
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California at Davis, Sacramento, CA 95817, USA;
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children—Northern California, Sacramento, CA 95817, USA
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14
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Chu KY, Wang YL, Chou YR, Chen JT, Wang YP, Simmer JP, Hu JCC, Wang SK. Synergistic Mutations of LRP6 and WNT10A in Familial Tooth Agenesis. J Pers Med 2021; 11:jpm11111217. [PMID: 34834569 PMCID: PMC8621929 DOI: 10.3390/jpm11111217] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/13/2021] [Accepted: 11/13/2021] [Indexed: 02/07/2023] Open
Abstract
Familial tooth agenesis (FTA), distinguished by developmental failure of selected teeth, is one of the most prevalent craniofacial anomalies in humans. Mutations in genes involved in WNT/β-catenin signaling, including AXIN2 WNT10A, WNT10B, LRP6, and KREMEN1, are known to cause FTA. However, mutational interactions among these genes have not been fully explored. In this study, we characterized four FTA kindreds with LRP6 pathogenic mutations: p.(Gln1252*), p.(Met168Arg), p.(Ala754Pro), and p.(Asn1075Ser). The three missense mutations were predicted to cause structural destabilization of the LRP6 protein. Two probands carrying both an LRP6 mutant allele and a WNT10A variant exhibited more severe phenotypes, suggesting mutational synergism or digenic inheritance. Biallelic LRP6 mutations in a patient with many missing teeth further supported the dose-dependence of LRP6-associated FTA. Analysis of 21 FTA cases with 15 different LRP6 loss-of-function mutations revealed high heterogeneity of disease severity and a distinctive pattern of missing teeth, with maxillary canines being frequently affected. We hypothesized that various combinations of sequence variants in WNT-related genes can modulate WNT signaling activities during tooth development and cause a wide spectrum of tooth agenesis severity, which highlights the importance of exome/genome analysis for the genetic diagnosis of FTA in this era of precision medicine.
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Affiliation(s)
- Kuan-Yu Chu
- Department of Dentistry, School of Dentistry, National Taiwan University, Taipei City 100, Taiwan; (K.-Y.C.); (Y.-L.W.); (J.-T.C.); (Y.-P.W.)
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City 100, Taiwan
| | - Yin-Lin Wang
- Department of Dentistry, School of Dentistry, National Taiwan University, Taipei City 100, Taiwan; (K.-Y.C.); (Y.-L.W.); (J.-T.C.); (Y.-P.W.)
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City 100, Taiwan
| | - Yu-Ren Chou
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei City 106, Taiwan;
| | - Jung-Tsu Chen
- Department of Dentistry, School of Dentistry, National Taiwan University, Taipei City 100, Taiwan; (K.-Y.C.); (Y.-L.W.); (J.-T.C.); (Y.-P.W.)
| | - Yi-Ping Wang
- Department of Dentistry, School of Dentistry, National Taiwan University, Taipei City 100, Taiwan; (K.-Y.C.); (Y.-L.W.); (J.-T.C.); (Y.-P.W.)
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48108, USA; (J.P.S.); (J.C.-C.H.)
| | - Jan C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI 48108, USA; (J.P.S.); (J.C.-C.H.)
| | - Shih-Kai Wang
- Department of Dentistry, School of Dentistry, National Taiwan University, Taipei City 100, Taiwan; (K.-Y.C.); (Y.-L.W.); (J.-T.C.); (Y.-P.W.)
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City 100, Taiwan
- Correspondence: ; Tel.: +886-2-23123456 (ext. 70251)
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15
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Zhang Z, Pan X, Chen M, Bai M. Wnt signalling in oral and maxillofacial diseases. Cell Biol Int 2021; 46:34-45. [PMID: 34643311 DOI: 10.1002/cbin.11708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/31/2021] [Accepted: 10/08/2021] [Indexed: 02/05/2023]
Abstract
Wnts include more than 19 types of secreted glycoproteins that are involved in a wide range of pathological processes in oral and maxillofacial diseases. The transmission of Wnt signalling from the extracellular matrix into the nucleus includes canonical pathways and noncanonical pathways, which play an important role in tooth development, alveolar bone regeneration, and related diseases. In recent years, with the in-depth study of Wnt signalling in oral and maxillofacial-related diseases, many new conclusions and perspectives have been reached, and there are also some controversies. This article aims to summarise the roles of Wnt signalling in various oral diseases, including periodontitis, dental pulp disease, jaw disease, cleft palate, and abnormal tooth development, to provide researchers with a better and more comprehensive understanding of Wnts in oral and maxillofacial diseases.
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Affiliation(s)
- Zhaowei Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xinyue Pan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mingyang Chen
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mingru Bai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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16
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Goto H, Kimura M, Machida J, Ota A, Nakashima M, Tsuchida N, Adachi J, Aoki Y, Tatematsu T, Takahashi K, Sana M, Nakayama A, Suzuki S, Nagao T, Matsumoto N, Tokita Y. A novel LRP6 variant in a Japanese family with oligodontia. Hum Genome Var 2021; 8:30. [PMID: 34285199 PMCID: PMC8292333 DOI: 10.1038/s41439-021-00162-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/27/2022] Open
Abstract
Congenital tooth agenesis is a common anomaly in human development. We performed exome sequence analysis of genomic DNA collected from Japanese patients with tooth agenesis and their relatives. We found a novel single-nucleotide insertion in the LRP6 gene, the product of which is involved in Wnt/β-catenin signaling as a coreceptor for Wnt ligands. The single-nucleotide insertion results in a premature stop codon in the extracellular region of the encoded protein.
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Affiliation(s)
- Hiroki Goto
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Oral and Maxillofacial Surgery, Toyokawa City Hospital, Toyokawa, Japan.,Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Masashi Kimura
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Oral and Maxillofacial Surgery, Ogaki Municipal Hospital, Ogaki, Japan.,Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Junichiro Machida
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Oral and Maxillofacial Surgery, Toyota Memorial Hospital, Toyota, Japan
| | - Akiko Ota
- Department of Oncology, Toyota Memorial Hospital, Toyota, Japan
| | - Mitsuko Nakashima
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomi Tsuchida
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.,Department of Stem Cell and Immune Regulation, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Junya Adachi
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Yoshihiko Aoki
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Tadashi Tatematsu
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Katsu Takahashi
- Dentistry and Oral surgery Tazuke Kofukai, Medical Research Institute, Kitano Hospital, Osaka, Japan
| | | | - Atsuo Nakayama
- Department of Cellular Pathology, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Shintaro Suzuki
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.,Department of Oral and Maxillofacial Surgery, Toyokawa City Hospital, Toyokawa, Japan
| | - Toru Nagao
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - Naomichi Matsumoto
- Department of Stem Cell and Immune Regulation, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yoshihito Tokita
- Department of Maxillofacial Surgery, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan. .,Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan.
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17
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Abstract
Skeletal integrity is maintained by a meticulous balance between bone resorption and bone formation, and recent studies have revealed the essential role of canonical Wnt signaling pathways in maintaining skeletal homeostasis. The SOST gene, which encodes sclerostin, a member of Dan family glycoproteins, was originally identified as the gene responsible for two sclerosing bone dysplasias, sclerosteosis and van Buchem disease. Sclerostin is highly expressed by osteocytes, negatively regulates canonical Wnt signaling pathways by binding to low-density lipoprotein receptor-related protein (LRP) 5/6, and suppresses osteoblast differentiation and/or function. Romosozumab, a specific anti-sclerostin antibody, inhibits sclerostin-LRP5/6 interactions and indirectly activates canonical Wnt signaling pathways and bone formation. This review focuses on the mechanism of action of sclerostin and summarizes clinical studies that demonstrated the efficacy of romosozumab to increase bone mineral density and reduce osteoporotic fractures, as well as its cardiovascular safety.
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Affiliation(s)
- Sakae Tanaka
- Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Toshio Matsumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
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18
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Abstract
The WNT/β-catenin signalling pathway is a rich and complex network of cellular proteins that orchestrates diverse short-range cell-to-cell communication in metazoans and is essential for both embryonic development and adult homeostasis. Due to its fundamental importance in controlling cell behaviour at multiple levels, its deregulation is associated with a wide range of diseases in humans and identification of drugs targeting the pathway has attracted strong interest in the pharmaceutical sector. Transduction of WNT signals across the plasma membrane of cells involves a staggering degree of complexity and variety with respect to ligand-receptor, receptor-receptor and receptor-co-receptor interactions (Niehrs, Nat Rev Mol Cell Biol 13:767-779, 2012). Although the low-density-lipoprotein-receptor-related-protein (LRP) family is best known for its role in binding and endocytosis of lipoproteins, specific members appear to have additional roles in cellular communication. Indeed, for WNT/β-catenin signalling one apparently universal requirement is the presence of either LRP5 or LRP6 in combination with one of the ten Frizzled (FZD) WNT receptors (FZD1-10). In the 20 years since their discovery as WNT/FZD co-receptors, research on the LRP family has contributed greatly to our understanding of WNT signalling and LRPs have emerged as central players in WNT/β-catenin signalling. LRP5/6 are highly similar and represent the least redundant class of WNT receptor that transduce WNT/β-catenin signalling from a wide range of different WNT and FZD subtypes. This apparent simplicity however belies the complex arrangement of binding sites in the extracellular domain (ECD) of LRP5/6, which regulate interaction not only with WNTs but also with several inhibitors of WNT signalling. This chapter provides a historical overview, chronologically charting this remarkable progress in the field during the last 20 years of research on LRPs and their role in WNT/-catenin signalling. A more focused overview of the structural, functional and mechanistic aspects of LRP biology is also provided, together with the implications this has for pharmacological targeting of this notoriously intractable pathway.
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Affiliation(s)
- Gary Davidson
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBSC-FMS), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
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