1
|
Bolamperti S, Villa I, Rubinacci A. Bone remodeling: an operational process ensuring survival and bone mechanical competence. Bone Res 2022; 10:48. [PMID: 35851054 PMCID: PMC9293977 DOI: 10.1038/s41413-022-00219-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 05/02/2022] [Accepted: 05/15/2022] [Indexed: 12/12/2022] Open
Abstract
Bone remodeling replaces old and damaged bone with new bone through a sequence of cellular events occurring on the same surface without any change in bone shape. It was initially thought that the basic multicellular unit (BMU) responsible for bone remodeling consists of osteoclasts and osteoblasts functioning through a hierarchical sequence of events organized into distinct stages. However, recent discoveries have indicated that all bone cells participate in BMU formation by interacting both simultaneously and at different differentiation stages with their progenitors, other cells, and bone matrix constituents. Therefore, bone remodeling is currently considered a physiological outcome of continuous cellular operational processes optimized to confer a survival advantage. Bone remodeling defines the primary activities that BMUs need to perform to renew successfully bone structural units. Hence, this review summarizes the current understanding of bone remodeling and future research directions with the aim of providing a clinically relevant biological background with which to identify targets for therapeutic strategies in osteoporosis.
Collapse
Affiliation(s)
- Simona Bolamperti
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Isabella Villa
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Alessandro Rubinacci
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy.
| |
Collapse
|
2
|
Wongdee K, Lertsuwan K, Thonapan N, Teerapornpuntakit J, Charoenphandhu N. Differential expression of Sox9 protein and proteoglycans in the epiphyseal cartilage of bromocriptine-treated pregnant and lactating rats. Anat Sci Int 2019; 95:277-285. [PMID: 31865549 DOI: 10.1007/s12565-019-00520-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/09/2019] [Indexed: 10/25/2022]
Abstract
Several investigations have shown that pregnancy and lactation are able to induce elongation of long bone by altering epiphyseal cartilage function in a prolactin-dependent manner. Since the transcription factor Sox9 is of utmost importance for chondrocyte proliferation and differentiation and since bromocriptine, a dopaminergic D2 agonist widely used to suppress milk production, is known to disrupt the production and release of prolactin, we herein aimed to investigate whether pregnancy and lactation as well as bromocriptine could alter the expression of Sox9. Our immunohistochemical analysis showed that the Sox9 expression levels were markedly upregulated in the tibial proliferative zone of day 21 pregnant rats. In day 8 (early) and day 14 (mid) lactating rats, the Sox9 expression was enhanced only in the proliferative zone, but not in the resting and hypertrophic zones. There was no change in Sox9 expression in day 21 (late) lactating rats. Postweaning rats manifested a decreased Sox9 expression in the hypertrophic zone. Bromocriptine had no effect on Sox9 expression in the proliferative zone of day 21 pregnant rats; however, it completely prevented the Sox9 upregulation in those of early and mid-lactating rats. A differential response was observed in the proliferative and hypertrophic zones of late lactating rats, in which bromocriptine enhanced Sox9 expression. Further investigation of cartilaginous matrix revealed no change in proteoglycans accumulation in lactating rats. In conclusion, the upregulated Sox9 expression predominantly occurred in the proliferative zone during late pregnancy and early and mid-lactation, while the bromocriptine effects depended on the periods and epiphyseal zones.
Collapse
Affiliation(s)
- Kannikar Wongdee
- Faculty of Allied Health Sciences, Burapha University, Chonburi, 20131, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Kornkamon Lertsuwan
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Natchayaporn Thonapan
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. .,Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand. .,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, 73170, Thailand. .,The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, 10300, Thailand.
| |
Collapse
|
3
|
Dedic C, Hung TS, Shipley AM, Maeda A, Gardella T, Miller AL, Divieti Pajevic P, Kunkel JG, Rubinacci A. Calcium fluxes at the bone/plasma interface: Acute effects of parathyroid hormone (PTH) and targeted deletion of PTH/PTH-related peptide (PTHrP) receptor in the osteocytes. Bone 2018; 116:135-143. [PMID: 30053608 PMCID: PMC6158063 DOI: 10.1016/j.bone.2018.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/20/2018] [Accepted: 07/24/2018] [Indexed: 01/10/2023]
Abstract
Calcium ion concentration ([Ca2+]) in the systemic extracellular fluid, ECF-[Ca2+], is maintained around a genetically predetermined set-point, which combines the operational level of the kidney and bone/ECF interfaces. The ECF-[Ca2+] is maintained within a narrow oscillation range by the regulatory action of Parathyroid Hormone (PTH), Calcitonin, FGF-23, and 1,25(OH)2D3. This model implies two correction mechanisms, i.e. tubular Ca2+ reabsorption and osteoclast Ca2+ resorption. Although their alterations have an effect on the ECF-[Ca2+] maintenance, they cannot fully account for rapid correction of the continuing perturbations of plasma [Ca2+], which occur daily in life. The existence of Ca2+ fluxes at quiescent bone surfaces fulfills the role of a short-term error correction mechanism in Ca2+ homeostasis. To explore the hypothesis that PTH regulates the cell system responsible for the fast Ca2+ fluxes at the bone/ECF interface, we have performed direct real-time measurements of Ca2+ fluxes at the surface of ex-vivo metatarsal bones maintained in physiological conditions mimicking ECF, and exposed to PTH. To further characterize whether the PTH receptor on osteocytes is a critical component of the minute-to-minute ECF-[Ca2+] regulation, metatarsal bones from mice lacking the PTH receptor in these cells were tested ex vivo for rapid Ca2+ exchange. We performed direct real-time measurements of Ca2+ fluxes and concentration gradients by a scanning ion-selective electrode technique (SIET). To validate ex vivo measurements, we also evaluated acute calcemic response to PTH in vivo in mice lacking PTH receptors in osteocytes vs littermate controls. Our data demonstrated that Ca2+ fluxes at the bone-ECF interface in excised bones as well as acute calcemic response in the short-term were unaffected by PTH exposure and its signaling through its receptor in osteocytes. Rapid minute-to-minute regulation of the ECF-[Ca2+] was found to be independent of PTH actions on osteocytes. Similarly, mice lacking PTH receptor in osteocytes, responded to PTH challenge with similar calcemic increases.
Collapse
Affiliation(s)
- Christopher Dedic
- Molecular and Cell Biology, Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Tin Shing Hung
- Division of Life Sciences, State Key Laboratory for Molecular Neuroscience, HKUST, Hong Kong, China
| | | | - Akira Maeda
- Endocrine Unit, Massachusetts General Hospital, Boston, USA; Chugai Pharmaceutical, Japan
| | | | - Andrew L Miller
- Division of Life Sciences, State Key Laboratory for Molecular Neuroscience, HKUST, Hong Kong, China
| | - Paola Divieti Pajevic
- Molecular and Cell Biology, Goldman School of Dental Medicine, Boston University, Boston, MA, USA
| | - Joseph G Kunkel
- Pickus Center for Biomedical Research, University of New England, Biddeford, ME, USA
| | - Alessandro Rubinacci
- Bone Metabolism Unit, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milano, Italy.
| |
Collapse
|
4
|
Arcidiacono T, Simonini M, Lanzani C, Citterio L, Salvi E, Barlassina C, Spotti D, Cusi D, Manunta P, Vezzoli G. Claudin-14 Gene Polymorphisms and Urine Calcium Excretion. Clin J Am Soc Nephrol 2018; 13:1542-1549. [PMID: 30232134 PMCID: PMC6218816 DOI: 10.2215/cjn.01770218] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 08/03/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND OBJECTIVES Claudin-16 and -19 are proteins forming pores for the paracellular reabsorption of divalent cations in the ascending limb of Henle loop; conversely, claudin-14 decreases ion permeability of these pores. Single-nucleotide polymorphisms in gene coding for claudin-14 were associated with kidney stones and calcium excretion. This study aimed to explore the association of claudin-14, claudin-16, and claudin-19 single-nucleotide polymorphisms with calcium excretion. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We performed a retrospective observational study of 393 patients with hypertension who were naïve to antihypertensive drugs, in whom we measured 24-hour urine calcium excretion; history of kidney stones was ascertained by interview; 370 of these patients underwent an intravenous 0.9% sodium chloride infusion (2 L in 2 hours) to evaluate the response of calcium excretion in three different 2-hour urine samples collected before, during, and after saline infusion. Genotypes of claudin-14, claudin-16, and claudin-19 were obtained from data of a previous genome-wide association study in the same patients. RESULTS Thirty-one single-nucleotide polymorphisms of the 3' region of the claudin-14 gene were significantly associated with 24-hour calcium excretion and calcium excretion after saline infusion. The most significant associated single-nucleotide polymorphism was rs219755 (24-hour calcium excretion in GG, 225±124 mg/24 hours; 24-hour calcium excretion in GA, 194±100 mg/24 hours; 24-hour calcium excretion in AA, 124±73 mg/24 hours; P<0.001; calcium excretion during saline infusion in GG, 30±21 mg/2 hours; calcium excretion during saline infusion in GA, 29±18 mg/2 hours; calcium excretion during saline infusion in AA, 17±11 mg/2 hours; P=0.03). No significant associations were found among claudin-16 and claudin-19 single-nucleotide polymorphisms and calcium excretion and between claudin-14, claudin-16, and claudin-19 single-nucleotide polymorphisms and stones. Bioinformatic analysis showed that one single-nucleotide polymorphism at claudin-14 among those associated with calcium excretion may potentially influence splicing of transcript. CONCLUSIONS Claudin-14 genotype at the 3' region is associated with calcium excretion in 24-hour urine and after the calciuretic stimulus of saline infusion.
Collapse
Affiliation(s)
- Teresa Arcidiacono
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Marco Simonini
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Chiara Lanzani
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Lorena Citterio
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Erika Salvi
- Department of Health Sciences, University of Milan, Milan, Italy; and
- Filarete Foundation, Milan, Italy
| | - Cristina Barlassina
- Department of Health Sciences, University of Milan, Milan, Italy; and
- Filarete Foundation, Milan, Italy
| | - Donatella Spotti
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Daniele Cusi
- Department of Health Sciences, University of Milan, Milan, Italy; and
- Filarete Foundation, Milan, Italy
| | - Paolo Manunta
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| | - Giuseppe Vezzoli
- Nephrology and Dialysis Unit, IRCCS San Raffaele Scientific Institute, Genomics of Renal Diseases and Hypertension Unit, Vita Salute San Raffaele University, Milan, Italy
| |
Collapse
|
5
|
Lv F, Xu XJ, Wang JY, Liu Y, Jiang Y, Wang O, Xia WB, Xing XP, Li M. A novel mutation in CLDN16 results in rare familial hypomagnesaemia with hypercalciuria and nephrocalcinosis in a Chinese family. Clin Chim Acta 2016; 457:69-74. [PMID: 27067446 DOI: 10.1016/j.cca.2016.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/30/2016] [Accepted: 04/06/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessively inherited disease characterized by excessive wasting of renal tubular magnesium and calcium. FHHNC is associated with various mutations in CLDN16 and CLDN19. CASES Two children from a consanguineous family of Chinese Han origin demonstrated manifestations of rickets, polyuria, polydipsia, hematuria and failure to thrive. Hypomagnesaemia (0.49-0.50mmol/L), hypercalciuria or a trend to hypercalciuria (24hour urine calcium: 3.8-5.1mg/kg/day), and secondary hyperparathyroidism (serum PTH level: 94.7-200pg/mL) were revealed upon laboratory examination. Using targeted next-generation sequencing and subsequent confirmation by Sanger sequencing, a novel homozygous mutation was identified in the CLDN16 gene of both FHHNC patients. This specific mutation, a 16bp deletion followed by a 23bp insertion in exon 3, led to the generation of a premature termination codon. The parents and an unaffected sister were all heterozygous carriers of this mutation. CONCLUSIONS We detected a novel mutation in CLDN16 for the first time. The clinical and genetic findings from this study will help to expand the understanding of this rare disease, FHHNC.
Collapse
Affiliation(s)
- Fang Lv
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiao-Jie Xu
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Jian-Yi Wang
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yi Liu
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Ou Wang
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Wei-Bo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiao-Ping Xing
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Mei Li
- Department of Endocrinology, Key Laboratory of Endocrinology of Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
| |
Collapse
|
6
|
Abstract
The imbalance between bone formation and resorption during bone remodeling has been documented to be a major factor in the pathogenesis of osteoporosis. Recent evidence suggests a significant role for the tight junction proteins, Claudins (Cldns), in the regulation of bone remodeling processes. In terms of function, whereas Cldns act "canonically" as key determinants of paracellular permeability, there is considerable recent evidence to suggest that Cldns also participate in cell signaling, ie, a "noncanonical function". To this end, Cldns have been shown to regulate cell proliferation, differentiation, and gene expression in a variety of cell types. The present review will discuss Cldns' structure, their expression profile, regulation of expression, and their canonical and non- canonical functions in general with special emphasis on bone cells. In order to shed light on the noncanonical functions of Cldns in bone, we will highlight the role of Cldn-18 in regulating bone resorption and osteoclast differentiation. Collectively, we hope to provide a framework for guiding future research on understanding how Cldns modulate osteoblast and osteoclast function and overall bone homeostasis. Such studies should provide valuable insights into the pathogenesis of osteoporosis, and may highlight Cldns as novel targets for the diagnosis and therapeutic management of osteoporosis.
Collapse
Affiliation(s)
- Fatima Z Alshbool
- Musculoskeletal Disease Center (F.Z.A., S.M.), Jerry L. Pettis VA Medical Center, Loma Linda, CA 92357; Departments of Medicine (S.M.), Biochemistry (S.M.), Physiology (S.M.), and Pharmacology (F.Z.A., S.M.), Loma Linda University, Loma Linda, California 92354
| | | |
Collapse
|
7
|
Wongdee K, Thonapan N, Saengamnart W, Krishnamra N, Charoenphandhu N. Bromocriptine modulates the expression of PTHrP receptor, Indian hedgehog, and Runx2 proteins in the growth plate of lactating rats. Mol Cell Biochem 2013; 381:191-9. [DOI: 10.1007/s11010-013-1702-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/24/2013] [Indexed: 12/28/2022]
|
8
|
Thongon N, Krishnamra N. Apical acidity decreases inhibitory effect of omeprazole on Mg(2+) absorption and claudin-7 and -12 expression in Caco-2 monolayers. Exp Mol Med 2012; 44:684-93. [PMID: 22940736 PMCID: PMC3509185 DOI: 10.3858/emm.2012.44.11.077] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Clinical studies reported hypomagnesaemia in long-term omeprazole usage that was probably due to intestinal Mg(2+) wasting. Our previous report demonstrated the inhibitory effect of omeprazole on passive Mg(2+) transport across Caco-2 monolayers. The present study aimed to identify the underlying mechanism of omeprazole suppression of passive Mg(2+) absorption. By using Caco-2 monolayers, we demonstrated a potent inhibitory effect of omeprazole on passive Mg(2+), but not Ca(2+), transport across Caco-2 monolayers. Omeprazole shifted the %maximum passive Mg(2+) transport-Mg(2+) concentration curves to the right, and increased the half maximal effective concentration of those dose-response curves, indicating a lower Mg(2+) affinity of the paracellular channel. By continually monitoring the apical pH, we showed that omeprazole suppressed apical acid accumulation. Neomycin and spermine had no effect on passive Mg(2+) transport of either control or omeprazole treated monolayers, indicating that omeprazole suppressed passive Mg(2+) transport in a calcium sensing receptor (CaSR)-independent manner. The results of western blot analysis showed that omeprazole significantly suppressed claudin (Cldn)-7 and -12, but not Cldn-2, expression in Caco-2 cells. By using apical solution of pH 5.5, 6.0, 6.5, and 7.0, we found that apical acidity markedly increased passive Mg(2+) transport, Mg(2+) affinity of the paracellular channel, and Cldn-7 and -12 expression in Caco-2 monolayers. Apical acidity abolished the inhibitory effect of omeprazole on passive Mg(2+) transport and Cldn-7 and -12 expression. Our results provided the evidence for the regulation of intestinal passive Mg(2+) absorption by luminal acidity-induced increase in Cldn-7 and -12 expression.
Collapse
Affiliation(s)
- Narongrit Thongon
- Faculty of Allied Health Sciences Burapha University Chonburi 20131, Thailand.
| | | |
Collapse
|
9
|
Duodenal villous hypertrophy and upregulation of claudin-15 protein expression in lactating rats. J Mol Histol 2012; 44:103-9. [PMID: 23001625 DOI: 10.1007/s10735-012-9451-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 09/14/2012] [Indexed: 01/27/2023]
Abstract
In lactation, the intestinal absorption of nutrients and minerals, especially calcium, is markedly enhanced to supply precursors for milk production. Little is known regarding the mechanism of this lactation-induced intestinal hyperabsorption. However, it has been postulated to result from villous hypertrophy with enlarged absorptive area and the upregulation of the cation-selective tight junction protein claudin-15, which could form calcium-permeable paracellular pores, thereby enhancing the paracellular calcium absorption. Here, we demonstrated in the duodenum of 21-day lactating rats that there were increases in the villous height, villous width and crypt depth, which together led to expansion of absorptive surface area. Quantitative real-time PCR further showed that the mRNA levels of claudin-10 and -15 were increased in the duodenal mucosal cells of lactating rats as compared to age-matched unmated control rats. However, immunohistochemical analysis revealed the lactation-induced upregulation of claudin-15, but not claudin-10 protein expression in the duodenal villous cells. The present results, therefore, corroborated the previous hypothesis that lactation induced intestinal absorption of calcium and perhaps other cation minerals, in part, by increasing villous absorptive area and claudin-15 protein expression.
Collapse
|
10
|
Linares GR, Brommage R, Powell DR, Xing W, Chen ST, Alshbool FZ, Lau KHW, Wergedal JE, Mohan S. Claudin 18 is a novel negative regulator of bone resorption and osteoclast differentiation. J Bone Miner Res 2012; 27:1553-65. [PMID: 22437732 PMCID: PMC3377820 DOI: 10.1002/jbmr.1600] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Claudin 18 (Cldn-18) belongs to a large family of transmembrane proteins that are important components of tight junction strands. Although several claudin members are expressed in bone, the functional role for any claudin member in bone is unknown. Here we demonstrate that disruption of Cldn-18 in mice markedly decreased total body bone mineral density, trabecular bone volume, and cortical thickness in Cldn-18(-/-) mice. Histomorphometric studies revealed that bone resorption parameters were increased significantly in Cldn-18(-/-) mice without changes in bone formation. Serum levels of tartrate-resistant acid phosphatase 5b (TRAP5b) and mRNA expression levels of osteoclast specific markers and signaling molecules were also increased. Loss of Cldn-18 further exacerbated calcium deficiency induced bone loss by influencing bone resorption, thereby resulting in mechanically weaker bone. In vitro studies with bone marrow macrophages revealed Cldn-18 disruption markedly enhanced receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation but not macrophage colony-stimulating factor (MCSF)-induced bone marrow macrophage (BMM) proliferation. Consistent with a direct role for Cldn-18 in regulating osteoclast differentiation, overexpression of wild type but not PDZ binding motif deleted Cldn-18 inhibited RANKL-induced osteoclast differentiation. Furthermore, our findings indicate that Cldn-18 interacts with Zonula occludens 2 (ZO-2) to modulate RANKL signaling in osteoclasts. In conclusion, we demonstrate that Cldn-18 is a novel negative regulator of bone resorption and osteoclast differentiation.
Collapse
Affiliation(s)
- Gabriel R. Linares
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Physiology, Loma Linda University, Loma Linda, CA 92354, USA
| | | | | | - Weirong Xing
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Shin-Tai Chen
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Biochemistry, Loma Linda University, Loma Linda, CA 92354, USA
- Department of Microbiology, Loma Linda University, Loma Linda, CA 92354, USA
| | - Fatima Z. Alshbool
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Pharmacology, Loma Linda University, Loma Linda, CA 92354, USA
| | - KH William Lau
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
- Department of Biochemistry, Loma Linda University, Loma Linda, CA 92354, USA
| | - Jon E. Wergedal
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, CA 92357, USA
- Department of Physiology, Loma Linda University, Loma Linda, CA 92354, USA
- Department of Medicine, Loma Linda University, Loma Linda, CA 92354, USA
- Department of Biochemistry, Loma Linda University, Loma Linda, CA 92354, USA
| |
Collapse
|
11
|
Zhang S, Mark KS. α1-Acid glycoprotein induced effects in rat brain microvessel endothelial cells. Microvasc Res 2012; 84:161-8. [PMID: 22633841 DOI: 10.1016/j.mvr.2012.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 04/13/2012] [Accepted: 05/10/2012] [Indexed: 01/01/2023]
Abstract
α1-Acid glycoprotein (AGP) is a positive acute phase protein which is elevated 1-10 times during inflammation. Whereas AGP has been reported to have immunomodulatory properties, other biological functions of this protein such as its effects on the blood-brain barrier (BBB) endothelium are unknown. Tight junction (TJ) proteins (ZO-1 and occludin) are crucial in maintaining BBB integrity and brain homeostasis. As inflammatory cytokines have been shown to alter BBB integrity and TJ protein expression, we hypothesized that AGP changes BBB function by stimulating inflammatory cytokines and/or directly modulating TJ protein expression. We used primary rat brain microvessel endothelial cells (RBMECs) as an in vitro BBB model to study the direct effects of AGP on the brain microvasculature. No change in cytokine levels was detected in supernatant from AGP-treated RBMECs, despite increased mRNA expression by the cells. Paracellular permeability was decreased up to 20%, across RBMEC monolayers following treatment with AGP, suggesting its role in enhancing BBB integrity. RBMECs showed a biphasic response of increased occludin protein expression following AGP treatment while ZO-1 expression changed in a dose- and time-dependent manner. These changes in TJ proteins suggest that AGP induced changes in occludin related to enhanced barrier properties while the change in ZO-1 may play a secondary role in BBB integrity and/or as an intracellular signaling molecule. AGP significantly changed transcription factor activator protein 1 (AP-1) DNA-binding activity which provides evidence of the potential cell signaling pathways that contribute to the effect of AGP in RBMECs. Together, this supports our hypothesis that AGP has a direct effect in brain microvasculature and may play an important role in altering BBB integrity in inflammatory-related diseases.
Collapse
Affiliation(s)
- Shuangling Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Science Center, Amarillo, TX 79106, USA.
| | | |
Collapse
|
12
|
Wongdee K, Tulalamba W, Thongbunchoo J, Krishnamra N, Charoenphandhu N. Prolactin alters the mRNA expression of osteoblast-derived osteoclastogenic factors in osteoblast-like UMR106 cells. Mol Cell Biochem 2010; 349:195-204. [PMID: 21116687 DOI: 10.1007/s11010-010-0674-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Accepted: 11/15/2010] [Indexed: 11/30/2022]
Abstract
Prolactin (PRL) is known to participate in the lactation-induced maternal bone loss, presumably by inducing the release of receptor activator of nuclear factor-κB ligand (RANKL), a potent osteoclastogenic factor from osteoblasts. Since maternal bone resorption was too massive to be solely explained by RANKL and osteoclasts did not express PRL receptors (PRLR), the involvement of some other osteoblast-derived osteoclastogenic modulators was anticipated. Herein, the authors used quantitative real-time PCR to investigate the mRNA expressions of various osteoclastogenic factors in osteoblast-like UMR106 cells directly exposed to PRL for 48 h. These cells were found to express PRLR and respond to 300 ng/ml PRL by increasing RANKL mRNA expression. This PRL concentration (comparable to plasma PRL levels in lactation) also induced the upregulation of monocyte chemoattractant protein (MCP)-1, cyclooxygenase (Cox)-2, and ephrin-B1, whereas a higher concentration (500 ng/ml) was required to upregulate tumor necrosis factor (TNF)-α and interleukin (IL)-1. However, 100-500 ng/ml PRL affected neither the cell proliferation, the cell viability nor the mRNA expressions of macrophage colony-stimulating factor, IL-6, ephrin type-B receptor 4 and ephrin-B2. In conclusion, besides RANKL overexpression, PRL upregulated the expressions of other osteoclastogenic modulators, i.e., MCP-1, Cox-2, TNF-α, IL-1, and ephrin-B1, thus, further explaining how PRL induced bone loss in lactating mothers.
Collapse
Affiliation(s)
- Kannikar Wongdee
- Consortium for Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | | | | | | |
Collapse
|
13
|
Possible chondroregulatory role of prolactin on the tibial growth plate of lactating rats. Histochem Cell Biol 2010; 134:483-91. [DOI: 10.1007/s00418-010-0745-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2010] [Indexed: 10/19/2022]
|