1
|
Marino S, Bellido T. PTH receptor signalling, osteocytes and bone disease induced by diabetes mellitus. Nat Rev Endocrinol 2024; 20:661-672. [PMID: 39020007 DOI: 10.1038/s41574-024-01014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/17/2024] [Indexed: 07/19/2024]
Abstract
Basic, translational and clinical research over the past few decades has provided new understanding on the mechanisms by which activation of the receptor of parathyroid hormone (parathyroid hormone 1 receptor (PTH1R)) regulates bone physiology and pathophysiology. A fundamental change in the field emerged upon the recognition that osteocytes, which are permanent residents of bone and the most abundant cells in bone, are targets of the actions of natural and synthetic ligands of PTH1R (parathyroid hormone and abaloparatide, respectively), and that these cells drive essential actions related to bone remodelling. Among the numerous genes regulated by PTH1R in osteocytes, SOST (which encodes sclerostin, the WNT signalling antagonist and inhibitor of bone formation) has a critical role in bone homeostasis and changes in its expression are associated with several bone pathologies. The bone fragility syndrome induced by diabetes mellitus is accompanied by increased osteocyte apoptosis and changes in the expression of osteocytic genes, including SOST. This Review will discuss advances in our knowledge of the role of osteocytes in PTH1R signalling and the new opportunities to restore bone health in diabetes mellitus by targeting the osteocytic PTH1R-sclerostin axis.
Collapse
Affiliation(s)
- Silvia Marino
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA
| | - Teresita Bellido
- Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
- Central Arkansas Veterans Healthcare System, John L. McClellan Little Rock, Little Rock, AR, USA.
- Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| |
Collapse
|
2
|
Momenzadeh K, Yeritsyan D, Abbasian M, Kheir N, Hanna P, Wang J, Dosta P, Papaioannou G, Goldfarb S, Tang CC, Amar-Lewis E, Nicole Prado Larrea M, Martinez Lozano E, Yousef M, Wixted J, Wein M, Artzi N, Nazarian A. Stimulation of fracture mineralization by salt-inducible kinase inhibitors. Front Bioeng Biotechnol 2024; 12:1450611. [PMID: 39359266 PMCID: PMC11445660 DOI: 10.3389/fbioe.2024.1450611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 08/19/2024] [Indexed: 10/04/2024] Open
Abstract
Introduction Over 6.8 million fractures occur annually in the US, with 10% experiencing delayed- or non-union. Anabolic therapeutics like PTH analogs stimulate fracture repair, and small molecule salt inducible kinase (SIK) inhibitors mimic PTH action. This study tests whether the SIK inhibitor YKL-05-099 accelerates fracture callus osteogenesis. Methods 126 female mice underwent femoral shaft pinning and midshaft fracture, receiving daily injections of PBS, YKL-05-099, or PTH. Callus tissues were analyzed via RT-qPCR, histology, single-cell RNA-seq, and μCT imaging. Biomechanical testing evaluated tissue rigidity. A hydrogel-based delivery system for PTH and siRNAs targeting SIK2/SIK3 was developed and tested. Results YKL-05-099 and PTH-treated mice showed higher mineralized callus volume fraction and improved structural rigidity. RNA-seq indicated YKL-05-099 increased osteoblast subsets and reduced chondrocyte precursors. Hydrogel-released siRNAs maintained target knockdown, accelerating callus mineralization. Discussion YKL-05-099 enhances fracture repair, supporting selective SIK inhibitors' development for clinical use. Hydrogel-based siRNA delivery offers targeted localized treatment at fracture sites.
Collapse
Affiliation(s)
- Kaveh Momenzadeh
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Diana Yeritsyan
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Mohammadreza Abbasian
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Nadim Kheir
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Philip Hanna
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Jialiang Wang
- The Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Pere Dosta
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
- Wyss Institute for Biologically-Inspired Engineering, Harvard University, Boston, MA, United States
| | - Garyfallia Papaioannou
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sarah Goldfarb
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Cheng-Chia Tang
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Eliz Amar-Lewis
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
- Wyss Institute for Biologically-Inspired Engineering, Harvard University, Boston, MA, United States
| | - Michaela Nicole Prado Larrea
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Edith Martinez Lozano
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Mohamed Yousef
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - John Wixted
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Marc Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Natalie Artzi
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
- Wyss Institute for Biologically-Inspired Engineering, Harvard University, Boston, MA, United States
| | - Ara Nazarian
- Musculoskeletal Translational Innovation Initiative, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
- Department of Mechanical Engineering, Boston University, Boston, MA, United States
- Department of Orthopaedic Surgery, Yerevan State Medical University, Yerevan, Armenia
| |
Collapse
|
3
|
Gifre L, Massó E, Fusaro M, Haarhaus M, Ureña P, Cozzolino M, Mazzaferro S, Calabia J, Peris P, Bover J. Vertebral fractures in patients with CKD and the general population: a call for diagnosis and action. Clin Kidney J 2024; 17:sfae191. [PMID: 39099567 PMCID: PMC11294886 DOI: 10.1093/ckj/sfae191] [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: 12/11/2023] [Indexed: 08/06/2024] Open
Abstract
Vertebral fractures (VFs) are the most common osteoporotic fractures in the general population, and they have been associated with high mortality, decreased quality of life, and high risk of subsequent fractures, especially when recent, multiple, or severe. Currently, VF diagnosis and classification determine fracture risk and the most appropriate anti-osteoporotic treatment. However, VFs are clearly underdiagnosed, especially in patients with chronic kidney disease (CKD), and CKD-associated osteoporosis has been disregarded until recently. VFs are associated with higher morbidity and mortality, and their prevalence and incidence differ depending on the grade of renal dysfunction (CKD G1-G5) and/or the type of renal replacement therapy (dialysis or transplantation). In addition to classical risk factors [such as higher age, female sex, reduced bone mineral density, diabetes and steroid use], various other factors have been associated with an increased risk of VFs in CKD, including CKD grade, haemodialysis vintage, time since renal transplantation, low or high intact parathyroid hormone and phosphate levels, and/or vitamin D and K1 deficiencies. Importantly, several clinical societies have recently modified their algorithms according to the fracture risk classification (including the presence of VFs) and determined the most appropriate anti-osteoporotic treatment for the general population. However, there are no specific guidelines addressing this topic in patients with CKD despite an important paradigm shift regarding the prognostic value of bone mineral density in 2017 after the publication of the CKD-Mineral and Bone Disorder Kidney Disease: Improving Global Outcomes guidelines. A proactive attitude towards diagnosis, treatment, and research is proposed to avoid therapeutic nihilism.
Collapse
Affiliation(s)
- Laia Gifre
- Rheumatology Department, Hospital Germans Trias i Pujol, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Catalonia, Spain
| | - Elisabet Massó
- Nephrology Department, University Hospital Germans Trias i Pujol, REMAR-IGTP Group, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Catalonia, Spain
| | - Maria Fusaro
- National Research Council (CNR), Institute of Clinical Physiology, Pisa (Italy). Department of Medicine, University of Padua, Padua, Italy
| | - Mathias Haarhaus
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden
- Diaverum AB, Hyllie Boulevard 53, Malmö, Sweden
| | - Pablo Ureña
- Department of Nephrology and Dialysis, AURA Nord Saint-Ouen, Saint-Ouen, Paris, France
- Department of Renal Physiology, Necker Hospital, University of Paris Descartes, Paris, France
| | - Mario Cozzolino
- Renal Division, Department of Health Sciences, University of Milan, Milan, Italy
| | - Sandro Mazzaferro
- Department of Translation and Precision Medicine, Sapienza University of Rome, Rome, Italy
| | - Jordi Calabia
- Nephrology Department, University Hospital Josep Trueta. IdIBGi Research Institute. Universitat de Girona, Catalonia, Spain
| | - Pilar Peris
- Rheumatology Department, Hospital Clinic de Barcelona, IDIBAPS, University of Barcelona, Barcelona, Catalonia, Spain
| | - Jordi Bover
- Nephrology Department, University Hospital Germans Trias i Pujol, REMAR-IGTP Group, Research Institute Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Catalonia, Spain
| |
Collapse
|
4
|
Lv Z, Zhang J, Liang S, Zhou C, Hu D, Brooks DJ, Bouxsein ML, Lanske B, Kostenuik P, Gori F, Baron R. Comparative study in estrogen-depleted mice identifies skeletal and osteocyte transcriptomic responses to abaloparatide and teriparatide. JCI Insight 2023; 8:e161932. [PMID: 37870958 PMCID: PMC10619488 DOI: 10.1172/jci.insight.161932] [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: 05/18/2022] [Accepted: 09/08/2023] [Indexed: 10/25/2023] Open
Abstract
Osteocytes express parathyroid hormone (PTH)/PTH-related protein (PTHrP) receptors and respond to the PTHrP analog abaloparatide (ABL) and to the PTH 1-34 fragment teriparatide (TPTD), which are used to treat osteoporosis. Several studies indicate overlapping but distinct skeletal responses to ABL or TPTD, but their effects on cortical bone may differ. Little is known about their differential effects on osteocytes. We compared cortical osteocyte and skeletal responses to ABL and TPTD in sham-operated and ovariectomized mice. Administered 7 weeks after ovariectomy for 4 weeks at a dose of 40 μg/kg/d, TPTD and ABL had similar effects on trabecular bone, but ABL showed stronger effects in cortical bone. In cortical osteocytes, both treatments decreased lacunar area, reflecting altered peri-lacunar remodeling favoring matrix accumulation. Osteocyte RNA-Seq revealed that several genes and pathways were altered by ovariectomy and affected similarly by TPTD and ABL. Notwithstanding, several signaling pathways were uniquely regulated by ABL. Thus, in mice, TPTD and ABL induced a positive osteocyte peri-lacunar remodeling balance, but ABL induced stronger cortical responses and affected the osteocyte transcriptome differently. We concluded that ABL affected the cortical osteocyte transcriptome in a manner subtly different from TPTD, resulting in more beneficial remodeling/modeling changes and homeostasis of the cortex.
Collapse
Affiliation(s)
- Zhengtao Lv
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Jiaming Zhang
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Shuang Liang
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Chenhe Zhou
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Dorothy Hu
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Daniel J. Brooks
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Mary L. Bouxsein
- Center for Advanced Orthopedic Studies, Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Harvard Medical School and Massachusetts General Hospital (MGH) Endocrine Unit, Boston, Massachusetts, USA
| | | | | | - Francesca Gori
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Roland Baron
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
- Harvard Medical School and Massachusetts General Hospital (MGH) Endocrine Unit, Boston, Massachusetts, USA
| |
Collapse
|
5
|
Gibadullin R, Kim TW, Tran LML, Gellman SH. Hormone Analogues with Unique Signaling Profiles from Replacement of α-Residue Triads with β/γ Diads. J Am Chem Soc 2023; 145:20539-20550. [PMID: 37697685 PMCID: PMC10588032 DOI: 10.1021/jacs.3c06703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
We have applied an underexplored backbone modification strategy to generate new analogues of peptides that activate two clinically important class B1 G protein-coupled receptors (GPCRs). Most peptide modification strategies involve changing side chains or, less commonly, changing the configuration at side chain-bearing carbons (i.e., l residues replaced by d residues). In contrast, backbone modifications alter the number of backbone atoms and the identities of backbone atoms relative to a poly-α-amino acid backbone. Starting from the peptide agonists PTH(1-34) (the first 34 residues of the parathyroid hormone, used clinically as the drug teriparatide) and glucagon-like peptide-1 (7-36) (GLP-1(7-36)), we replaced native α-residue triads with a diad composed of a β-amino acid residue and a γ-amino acid residue. The β/γ diad retains the number of backbone atoms in the ααα triad. Because the β and γ residue each bear a single side chain, we implemented ααα→βγ replacements at sites that contained a Gly residue (i.e., at α-residue triads that presented only two side chains). All seven of the α/β/γ-peptides derived from PTH(1-34) or GLP-1(7-36) bind to the cognate receptor (the PTHR1 or the GLP-1R), but they vary considerably in their activity profiles. Outcomes include functional mimicry of the all-α agonist, receptor-selective agonist activity, biased agonism, or strong binding with weak activation, which could lead to antagonist development. Collectively, these findings demonstrate that ααα→βγ replacements, which are easily implemented via solid-phase synthesis, can generate peptide hormone analogues that display unique and potentially useful signaling behavior.
Collapse
Affiliation(s)
- Ruslan Gibadullin
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
- Present address: Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Tae Wook Kim
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Lauren My-Linh Tran
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| |
Collapse
|
6
|
Cary BP, Gerrard EJ, Belousoff MJ, Fletcher MM, Jiang Y, Russell IC, Piper SJ, Wootten D, Sexton PM. Molecular insights into peptide agonist engagement with the PTH receptor. Structure 2023:S0969-2126(23)00125-9. [PMID: 37148874 DOI: 10.1016/j.str.2023.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/30/2022] [Accepted: 04/03/2023] [Indexed: 05/08/2023]
Abstract
The parathyroid hormone (PTH) 1 receptor (PTH1R) is a G protein-coupled receptor (GPCR) that regulates skeletal development and calcium homeostasis. Here, we describe cryo-EM structures of the PTH1R in complex with fragments of the two hormones, PTH and PTH-related protein, the drug abaloparatide, as well as the engineered tool compounds, long-acting PTH (LA-PTH) and the truncated peptide, M-PTH(1-14). We found that the critical N terminus of each agonist engages the transmembrane bundle in a topologically similar fashion, reflecting similarities in measures of Gαs activation. The full-length peptides induce subtly different extracellular domain (ECD) orientations relative to the transmembrane domain. In the structure bound to M-PTH, the ECD is unresolved, demonstrating that the ECD is highly dynamic when unconstrained by a peptide. High resolutions enabled identification of water molecules near peptide and G protein binding sites. Our results illuminate the action of orthosteric agonists of the PTH1R.
Collapse
Affiliation(s)
- Brian P Cary
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia.
| | - Elliot J Gerrard
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Matthew J Belousoff
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Madeleine M Fletcher
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Yan Jiang
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Isabella C Russell
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Sarah J Piper
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia
| | - Denise Wootten
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia.
| | - Patrick M Sexton
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia; ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, VIC, Australia.
| |
Collapse
|
7
|
Li Y, Qian Y, Qiao H, Pan W, Xie L, Li Y. Abaloparatide outperforms teriparatide in protecting against alveolar bone loss in experimental periodontitis. J Periodontol 2023; 94:244-255. [PMID: 35892139 DOI: 10.1002/jper.22-0211] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 06/18/2022] [Accepted: 07/13/2022] [Indexed: 02/05/2023]
Abstract
BACKGROUND The aim of this study was to compare the effects of two osteoanabolic drugs, abaloparatide (ABL) and teriparatide (TPTD), on protecting alveolar bone in experimental periodontitis. METHODS Twenty-four 9-week-old, male, Sprague-Dawley rats were placed with silk suture around the right maxillary second molar, and then were randomly divided into three groups, that is, the ABL, TPTD, and saline group, receiving intermittent subcutaneous injections of ABL (80 μg/kg), TPTD (80 μg/kg) or saline respectively every other day for 4 weeks. Samples on both sides were assessed through micro-computerized tomography, histological, and immunohistochemical analysis. Mouse pre-osteoblast MC3T3 cell was cultured with lipopolysaccharide (LPS) and treated with ABL or TPTD, before assays of cell proliferation, alkaline phosphatase (ALP) activity and real-time polymerase chain reaction. RESULTS On the ligature side, both ABL and TPTD significantly reduced alveolar bone loss, and ABL had significantly better effects with higher expression of runt-related transcription factor 2 (RUNX2) and Bglap (formerly called osteocalcin); meanwhile, the ligature induced osteoclastogenesis and down-regulation of osteoprotegerin (OPG) was affected by neither drug. On the non-ligature side, ABL also showed better osteoanabolic effects. In vitro studies revealed that, in the presence of LPS, ABL, and TPTD similarly promoted MC3T3 proliferation, whereas ABL induced higher ALP activity and osteoblastic gene expression compared to TPTD. CONCLUSION Both ABL and TPTD protect and regenerate alveolar bone in experimental periodontitis, and ABL behaves even better than TPTD at the same dose, attributed to its stronger osteoanabolic effects in this context.
Collapse
Affiliation(s)
- Yuan Li
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuran Qian
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hui Qiao
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Weiyi Pan
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Liang Xie
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yu Li
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| |
Collapse
|
8
|
Abstract
G protein–coupled receptors (GPCRs) constitute the largest and pharmacologically most important family of cell-surface receptors. Some GPCRs interact specifically with receptor-activity-modifying proteins (RAMPs), but the consequences of this interaction for the receptor activation mechanism are not well understood. Using a set of fluorescent biosensors for the parathyroid hormone 1 receptor (PTH1R) and its downstream signaling partners, we show here that RAMP2 induces a unique, preactivated receptor state that shows faster activation and altered downstream signaling. This type of GPCR modulation may open new methods of drug design. Receptor-activity-modifying proteins (RAMPs) are ubiquitously expressed membrane proteins that associate with different G protein–coupled receptors (GPCRs), including the parathyroid hormone 1 receptor (PTH1R), a class B GPCR and an important modulator of mineral ion homeostasis and bone metabolism. However, it is unknown whether and how RAMP proteins may affect PTH1R function. Using different optical biosensors to measure the activation of PTH1R and its downstream signaling, we describe here that RAMP2 acts as a specific allosteric modulator of PTH1R, shifting PTH1R to a unique preactivated state that permits faster activation in a ligand-specific manner. Moreover, RAMP2 modulates PTH1R downstream signaling in an agonist-dependent manner, most notably increasing the PTH-mediated Gi3 signaling sensitivity. Additionally, RAMP2 increases both PTH- and PTHrP-triggered β-arrestin2 recruitment to PTH1R. Employing homology modeling, we describe the putative structural molecular basis underlying our functional findings. These data uncover a critical role of RAMPs in the activation and signaling of a GPCR that may provide a new venue for highly specific modulation of GPCR function and advanced drug design.
Collapse
|
9
|
Yoon SH, Tang CC, Wein MN. Salt inducible kinases and PTH1R action. VITAMINS AND HORMONES 2022; 120:23-45. [PMID: 35953111 DOI: 10.1016/bs.vh.2022.04.008] [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: 06/15/2023]
Abstract
Parathyroid hormone is a central regulator of calcium homeostasis. PTH protects the organism from hypocalcemia through its actions in bone and kidney. Recent physiologic studies have revealed key target genes for PTH receptor (PTH1R) signaling in these target organs. However, the complete signal transduction cascade used by PTH1R to accomplish these physiologic actions has remained poorly defined. Here we will review recent studies that have defined an important role for salt inducible kinases downstream of PTH1R in bone, cartilage, and kidney. PTH1R signaling inhibits the activity of salt inducible kinases. Therefore, direct SIK inhibitors represent a promising novel strategy to mimic PTH actions using small molecules. Moreover, a detailed understanding of the molecular circuitry used by PTH1R to exert its biologic effects will afford powerful new models to better understand the diverse actions of this important G protein coupled receptor in health and disease.
Collapse
Affiliation(s)
- Sung-Hee Yoon
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Cheng-Chia Tang
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Marc N Wein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.
| |
Collapse
|
10
|
Daley EJ, Yoon SH, Reyes M, Bruce M, Brooks DJ, Bouxsein M, Potts JT, Kronenberg HM, Wein MN, Lanske B, Jüppner H, Gardella TJ. Actions of Parathyroid Hormone Ligand Analogues in Humanized PTH1R Knockin Mice. Endocrinology 2022; 163:bqac054. [PMID: 35460406 PMCID: PMC9167040 DOI: 10.1210/endocr/bqac054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Indexed: 11/19/2022]
Abstract
Rodent models are commonly used to evaluate parathyroid hormone (PTH) and PTH-related protein (PTHrP) ligands and analogues for their pharmacologic activities and potential therapeutic utility toward diseases of bone and mineral ion metabolism. Divergence, however, in the amino acid sequences of rodent and human PTH receptors (rat and mouse PTH1Rs are 91% identical to the human PTH1R) can lead to differences in receptor-binding and signaling potencies for such ligands when assessed on rodent vs human PTH1Rs, as shown by cell-based assays in vitro. This introduces an element of uncertainty in the accuracy of rodent models for performing such preclinical evaluations. To overcome this potential uncertainty, we used a homologous recombination-based knockin (KI) approach to generate a mouse (in-host strain C57Bl/6N) in which complementary DNA encoding the human PTH1R replaces a segment (exon 4) of the murine PTH1R gene so that the human and not the mouse PTH1R protein is expressed. Expression is directed by the endogenous mouse promoter and hence occurs in all biologically relevant cells and tissues and at appropriate levels. The resulting homozygous hPTH1R-KI (humanized) mice were healthy over at least 10 generations and showed functional responses to injected PTH analog peptides that are consistent with a fully functional human PTH1R in target bone and kidney cells. The initial evaluation of these mice and their potential utility for predicting behavior of PTH analogues in humans is reported here.
Collapse
Affiliation(s)
- Eileen J Daley
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Sung-Hee Yoon
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Monica Reyes
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Michael Bruce
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Daniel J Brooks
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Mary Bouxsein
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - John T Potts
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Henry M Kronenberg
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Marc N Wein
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Beate Lanske
- Radius Health Inc, Boston, Massachusetts 02210, USA
| | - Harald Jüppner
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Thomas J Gardella
- Massachusetts General Hospital and Harvard Medical School, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| |
Collapse
|
11
|
Portales‐Castillo I, Dean T, Khatri A, Jüppner H, Gardella TJ. Functional Properties of Two Distinct PTH1R Mutants Associated With Either Skeletal Defects or Pseudohypoparathyroidism. JBMR Plus 2022; 6:e10604. [PMID: 35720667 PMCID: PMC9189904 DOI: 10.1002/jbm4.10604] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/11/2022] [Indexed: 12/03/2022] Open
Abstract
Consistent with a vital role of parathyroid hormone (PTH) receptor type 1 (PTH1R) in skeletal development, homozygous loss-of-function PTH1R mutations in humans results in neonatal lethality (Blomstrand chondrodysplasia), whereas such heterozygous mutations cause a primary failure of tooth eruption (PFE). Despite a key role of PTH1R in calcium and phosphate homeostasis, blood mineral ion levels are not altered in such cases of PFE. Recently, two nonlethal homozygous PTH1R mutations were identified in two unrelated families in which affected members exhibit either dental and skeletal abnormalities (PTH1R-V204E) or hypocalcemia and hyperphosphatemia (PTH1R-R186H). Arg186 and Val204 map to the first transmembrane helix of the PTH1R, and thus to a critical region of this class B G protein-coupled receptor. We used cell-based assays and PTH and PTH-related protein (PTHrP) ligand analogs to assess the impact of the R186H and V204E mutations on PTH1R function in vitro. In transiently transfected HEK293 cells, PTH1R-R186H mediated cyclic adenosine monophosphate (cAMP) responses to PTH(1-34) and PTHrP(1-36) that were of comparable potency to those observed on wild-type PTH1R (PTH1R-WT) (half maximal effective concentrations [EC50s] = 0.4nM to 1.2nM), whereas the response-maxima were significantly reduced for the PTH1R-V204E mutant (maximum effect [Emax] = 81%-77% of PTH1R-WT, p ≤ 0.004). Antibody binding to an extracellular hemagglutinin (HA) tag was comparable for PTH1R-R186H and PTH1R-WT, but was significantly reduced for PTH1R-V204E (maximum binding level [Bmax] = 44% ± 11% of PTH1R-WT, p = 0.002). The potency of cAMP signaling induced by a PTH(1-11) analog was reduced by ninefold and threefold, respectively, for PTH1R-R186H and PTH1R-V204E, relative to PTH1R-WT, and a PTH(1-15) radioligand analog that bound adequately to PTH1R-WT exhibited little or no specific binding to either mutant receptor. The data support a general decrease in PTH1R surface expression and/or function as a mechanism for PFE and a selective impairment in PTH ligand affinity as a potential PTH1R-mutation-based mechanism for pseudohypoparathyroidism. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Ignacio Portales‐Castillo
- Department of Medicine, Division of NephrologyMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
| | - Thomas Dean
- Endocrine UnitMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
| | - Ashok Khatri
- Endocrine UnitMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
| | - Harald Jüppner
- Endocrine UnitMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
- Pediatric Nephrology UnitMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
| | - Thomas J Gardella
- Endocrine UnitMassachusetts General Hospital, and Harvard Medical SchoolBostonMAUSA
| |
Collapse
|
12
|
Martin TJ. PTH1R Actions on Bone Using the cAMP/Protein Kinase A Pathway. Front Endocrinol (Lausanne) 2022; 12:833221. [PMID: 35126319 PMCID: PMC8807523 DOI: 10.3389/fendo.2021.833221] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/24/2021] [Indexed: 12/29/2022] Open
Abstract
After the initial signaling action of parathyroid hormone (PTH) on bone was shown to be activation of adenylyl cyclase, its target was found to be cells of the osteoblast lineage, to the exclusion of osteoclasts and their precursors. This led to the view that the osteoblast lineage regulated osteoclast formation, a proposal that was established when the molecular mechanisms of osteoclast formation were discovered. This is in addition to the effect of PTH1Rv signaling throughout the osteoblast differentiation process to favour the formation of bone-forming osteoblasts. Initial signaling in the PTH target cells through cAMP and protein kinase A (PKA) activation is extremely rapid, and marked by an amplification process in which the later event, PKA activation, precedes cAMP accumulation in time and is achieved at lower concentrations. All of this is consistent with the existence of "spare receptors", as is the case with several other peptide hormones. PTH-related protein (PTHrP), that was discovered as a cancer product, shares structural similarity with PTH in the amino-terminal domain that allows the hormone, PTH, and the autocrine/paracrine agent, PTHrP, to share actions upon a common G protein coupled receptor, PTH1R, through which they activate adenylyl cyclase with equivalent potencies. Studies of ligand-receptor kinetics have revealed that the PTH/PTH1R ligand-receptor complex, after initial binding and adenylyl cyclase activation at the plasma membrane, is translocated to the endosome, where adenylyl cyclase activation persists for a further short period. This behavior of the PTH1R resembles that of a number of hormones and other agonists that undergo such endosomal translocation. It remains to be determined whether and to what extent the cellular effects through the PTH1R might be influenced when endosomal is added to plasma membrane activation.
Collapse
Affiliation(s)
- T. John Martin
- Department of Medicine, St Vincent’s Institute of Medical Research, St Vincent’s Health, University of Melbourne, Fitzroy, VIC, Australia
| |
Collapse
|