title: Hypotonic stress induces RANKL via transient receptor potential melastatin 3 (TRPM3) and vaniloid 4 (TRPV4) in human PDL cells.
abstract: Bone remodeling occurs in response to various types of mechanical stress. The periodontal ligament (PDL) plays an important role in mechanical stress-mediated alveolar bone remodeling. However, the underlying mechanism at the cellular level has not been extensively studied. In this study, we investigated the effect of shear stress on the expression of bone remodeling factors, including receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL) and osteoprotegerin (OPG), as well as its upstream signaling pathway in primary human PDL cells. We applied hypotonic stress to reproduce shear stress to PDL cells. Hypotonic stress induced the messenger RNA (mRNA) and protein expression of RANKL but not OPG. It also increased intracellular Ca(2+) concentration ([Ca(2+)]i). Extracellular Ca(2+) depletion and nonspecific plasma membrane Ca(2+) channel blockers completely inhibited the increase in both [Ca(2+)]i and RANKL mRNA expression. We identified the expression and activation of transient receptor potential melastatin 3 (TRPM3) and vaniloid 4 (TRPV4) channels in PDL cells. Pregnenolone sulfate (PS) and 4α-phorbol 12, 13-didecanoate (4α-PDD), which are agonists of TRPM3 and TRPV4, augmented Ca(2+) influx and RANKL mRNA expression. Both pharmacological (2-aminoethoxydiphenyl borate [2-APB], ruthenium red [RR], ononetin [Ono], and HC 067047 [HC]) and genetic (small interfering RNA [siRNA]) inhibitors of TRPM3 and TRPV4 reduced the hypotonic stress-mediated increase in [Ca(2+)]i and RANKL mRNA expression. Our study shows that hypotonic stress induced RANKL mRNA expression via TRPM3- and TRPV4-mediated extracellular Ca(2+) influx and RANKL expression. This signaling pathway in PDL cells may play a critical role in mechanical stress-mediated alveolar bone remodeling.
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Korea BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: G Y
authors.initials: GY
authors.lastname: Son
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: Y M
authors.initials: YM
authors.lastname: Yang
authors.affiliation: Department of Advanced General Dentistry, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: W S
authors.initials: WS
authors.lastname: Park
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Korea.
authors.forename: I
authors.initials: I
authors.lastname: Chang
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seoul, Korea BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea dmshin@yuhs.ac.
authors.forename: D M
authors.initials: DM
authors.lastname: Shin
mesh_terms: D001696:Biomechanical Phenomena; D016723:Bone Remodeling / Q000502:physiology; D001896:Boron Compounds / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D020868:Gene Silencing; D006801:Humans; D007038:Hypotonic Solutions; D009025:Morpholines / Q000494:pharmacology; D053244:Osteoprotegerin / Q000096:biosynthesis; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D010704:Phorbols / Q000494:pharmacology; D011284:Pregnenolone / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D053245:RANK Ligand / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage; D012430:Ruthenium Red / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical; D050053:TRPM Cation Channels / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D050916:TRPV Cation Channels / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: C517592:4alpha-phorbol 12,13-didecanone; D001896:Boron Compounds; D002121:Calcium Channel Blockers; C573308:HC-067047; D007038:Hypotonic Solutions; D009025:Morpholines; D053244:Osteoprotegerin; D010704:Phorbols; D011758:Pyrroles; D053245:RANK Ligand; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D050053:TRPM Cation Channels; C475667:TRPM3 protein, human; D050916:TRPV Cation Channels; C416986:TRPV4 protein, human; C018370:pregnenolone sulfate; D012430:Ruthenium Red; D011284:Pregnenolone; C109986:2-aminoethoxydiphenyl borate
keywords: bone remodeling/regeneration; cell signaling; ion channels; mechanotransduction; osmotic stress; periodontal ligament