Papers - TAKEYA Ryu
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Altered Fhod3 expression involved in progressive high-frequency hearing loss via dysregulation of actin polymerization stoichiometry in the cuticular plate. Reviewed International coauthorship
Boussaty EC, Ninoyu Y, Andrade LR, Li Q, Takeya R, Sumimoto H, Ohyama T, Wahlin KJ, Manor U, Friedman RA
PLoS genetics 20 ( 3 ) e1011211 2024.3
Language：English Publishing type：Research paper (scientific journal) Publisher：PLoS Genetics
Age-related hearing loss (ARHL) is a common sensory impairment with complex underlying mechanisms. In our previous study, we performed a meta-analysis of genome-wide association studies (GWAS) in mice and identified a novel locus on chromosome 18 associated with ARHL specifically linked to a 32 kHz tone burst stimulus. Consequently, we investigated the role of Formin Homology 2 Domain Containing 3 (Fhod3), a newly discovered candidate gene for ARHL based on the GWAS results. We observed Fhod3 expression in auditory hair cells (HCs) primarily localized at the cuticular plate (CP). To understand the functional implications of Fhod3 in the cochlea, we generated Fhod3 overexpression mice (Pax2-Cre+/-; Fhod3Tg/+) (TG) and HC-specific conditional knockout mice (Atoh1-Cre+/-; Fhod3fl/fl) (KO). Audiological assessments in TG mice demonstrated progressive high-frequency hearing loss, characterized by predominant loss of outer hair cells, and a decreased phalloidin intensities of CP. Ultrastructural analysis revealed loss of the shortest row of stereocilia in the basal turn of the cochlea, and alterations in the cuticular plate surrounding stereocilia rootlets. Importantly, the hearing and HC phenotype in TG mice phenocopied that of the KO mice. These findings suggest that balanced expression of Fhod3 is critical for proper CP and stereocilia structure and function. Further investigation of Fhod3 related hearing impairment mechanisms may lend new insight towards the myriad mechanisms underlying ARHL, which in turn could facilitate the development of therapeutic strategies for ARHL.
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Hikmawan Wahyu Sulistomo, Takayuki Nemoto, Yohko Kage, Hajime Fujii, Taku Uchida, Kogo Takamiya, Hideki Sumimoto, Hiroaki Kataoka, Haruhiko Bito, and Ryu Takeya
Cerebral Cortex 31 ( 4 ) 2205 - 2219 2020.11
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Cerebral Cortex
Changes in the shape and size of the dendritic spines are critical for synaptic transmission. These morphological changes depend on dynamic assembly of the actin cytoskeleton and occur differently in various types of neurons. However, how the actin dynamics are regulated in a neuronal cell type-specific manner remains largely unknown. We show that Fhod3, a member of the formin family proteins that mediate F-actin assembly, controls the dendritic spine morphogenesis of specific subpopulations of cerebrocortical pyramidal neurons. Fhod3 is expressed specifically in excitatory pyramidal neurons within layers II/III and V of restricted areas of the mouse cerebral cortex. Immunohistochemical and biochemical analyses revealed the accumulation of Fhod3 in postsynaptic spines. Although targeted deletion of Fhod3 in the brain did not lead to any defects in the gross or histological appearance of the brain, the dendritic spines in pyramidal neurons within presumptive Fhod3-positive areas were morphologically abnormal. In primary cultures prepared from the Fhod3-depleted cortex, defects in spine morphology were only detected in Fhod3 promoter-active cells, a small population of pyramidal neurons, and not in Fhod3 promoter-negative pyramidal neurons. Thus, Fhod3 plays a crucial role in dendritic spine morphogenesis only in a specific population of pyramidal neurons in a cell type-specific manner.
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Formin homology 2 domain-containing 3 (Fhod3) controls neural plate morphogenesis in mouse cranial neurulation by regulating multidirectional apical constriction. Reviewed
Sulistomo HW, Nemoto T, Yanagita T, Takeya R
The Journal of biological chemistry 294 ( 8 ) 2924 - 2934 2018.12
Language：English Publishing type：Research paper (scientific journal)
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Interaction between cardiac myosin-binding protein C and formin Fhod3 Reviewed
Matsuyama S., Kage Y., Fujimoto N., Ushijima T., Tsuruda T., Kitamura K., Shiose A., Asada Y., Sumimoto H., Takeya R.
Proceedings of the National Academy of Sciences of the United States of America 115 ( 19 ) E4386 - E4395 2018.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Proceedings of the National Academy of Sciences of the United States of America
© 2018 National Academy of Sciences. All rights reserved. Mutations in cardiac myosin-binding protein C (cMyBP-C) are a major cause of familial hypertrophic cardiomyopathy. Although cMyBP-C has been considered to regulate the cardiac function via cross-bridge arrangement at the C-zone of the myosin-containing A-band, the mechanism by which cMyBP-C functions remains unclear. We identified formin Fhod3, an actin organizer essential for the formation and maintenance of cardiac sarcomeres, as a cMyBP-C–binding protein. The cardiac-specific N-terminal Ig-like domain of cMyBP-C directly interacts with the cardiac-specific N-terminal region of Fhod3. The interaction seems to direct the localization of Fhod3 to the C-zone, since a noncardiac Fhod3 variant lacking the cMyBP-C–binding region failed to localize to the C-zone. Conversely, the cardiac variant of Fhod3 failed to localize to the C-zone in the cMyBP-C–null mice, which display a phenotype of hypertrophic cardiomyopathy. The cardiomyopathic phenotype of cMyBP-C–null mice was further exacerbated by Fhod3 overexpression with a defect of sarcomere integrity, whereas that was partially ameliorated by a reduction in the Fhod3 protein levels, suggesting that Fhod3 has a deleterious effect on cardiac function under cMyBP-C–null conditions where Fhod3 is aberrantly mislocalized. Together, these findings suggest the possibility that Fhod3 contributes to the pathogenesis of cMyBP-C–related cardiomyopathy and that Fhod3 is critically involved in cMyBP-C–mediated regulation of cardiac function via direct interaction.
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Ushijima T., Fujimoto N., Matsuyama S., Kan-O M., Kiyonari H., Shioi G., Kage Y., Yamasaki S., Takeya R., Sumimoto H.
Journal of Biological Chemistry 293 ( 1 ) 148 - 162 2018.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Biological Chemistry
© 2018 by The American Society for Biochemistry and Molecular Biology, Inc. Cardiac development and function require actin-myosin interactions in the sarcomere, a highly organized contractile structure. Sarcomere assembly mediated by formin homology 2 domain-containing 3 (Fhod3), a member of formins that directs formation of straight actin filaments, is essential for embryonic cardiogenesis. However, the role of Fhod3 in the neonatal and adult stages has remained unknown. Here, we generated floxed Fhod3 mice to bypass the embryonic lethality of an Fhod3 knockout (KO). Perinatal KO of Fhod3 in the heart caused juvenile lethality at around day 10 after birth with enlarged hearts composed of severely impaired myofibrils, indicating that Fhod3 is crucial for postnatal heart development. Tamoxifeninduced conditional KO of Fhod3 in the adult heart neither led to lethal effects nor did it affect sarcomere structure and localization of sarcomere components. However, adult Fhod3-deleted mice exhibited a slight cardiomegaly and mild impairment of cardiac function, conditions that were sustained over 1 year without compensation during aging. In addition to these agerelated changes, systemic stimulation with the α1-adrenergic receptor agonist phenylephrine, which induces sustained hypertension and hypertrophy development, induced expression of fetal cardiac genes that was more pronounced in adult Fhod3- deleted mice than in the control mice, suggesting that Fhod3 modulates hypertrophic changes in the adult heart. We conclude that Fhod3 plays a crucial role in both postnatal cardiac development and functional maintenance of the adult heart.
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The expression of the formin Fhod3 in mouse tongue striated muscle Reviewed International coauthorship
Nakagawa Hikaru, Kage Yohko, Miura Ayako, Wahyu Sulistomo Hikmawan, Matsuyama Sho, Yamashita Yoshihiro, Takeya Ryu
Cell Structure and Function 49 ( 2 ) 111 - 122 2024.11
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Society for Cell Biology
The sarcomere is the contractile unit of striated muscle and is composed of actin and myosin filaments. There is increasing evidence to support that actin assembly mediated by Fhod3, a member of the formin family of proteins, is critical for sarcomere formation and maintenance in cardiac muscle. Fhod3, which is abundantly expressed in the heart, localizes to the center of sarcomeres and contributes to the regulation of the cardiac function, as evidenced by the fact that mutations in Fhod3 cause cardiomyopathy. However, the role of Fhod3 in skeletal muscle, another type of striated muscle, is unclear. We herein show that Fhod3 is expressed in the tongue at both mRNA and protein levels, although in smaller amounts than in the heart. To determine the physiological role of Fhod3 expressed in the tongue, we generated embryos lacking Fhod3 in the tongue. The tongue tissue of the Fhod3-depleted embryos did not show any significant structural defects, suggesting that Fhod3 is dispensable for normal development of the mouse tongue. Unexpectedly, the immunostaining analysis revealed the absence of specific sarcomeric signals for Fhod3 in the wild-type tongue when compared to the Fhod3-depleted tongue as a negative control, despite the use of antibodies that had previously been validated by immunostaining of heart tissues. Taken together, although Fhod3 protein is expressed at a significant level in the tongue, Fhod3 in the tongue does not appear to exhibit the same sarcomeric pattern as observed in the heart, suggesting a different role for Fhod3 in the tongue muscles.Key words: actin, formin, sarcomere, striated muscle
DOI： 10.1247/csf.24044
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Maruta, Toyoaki; Kouroki, Satoshi; Kurogi, Mio; Hidaka, Kotaro; Koshida, Tomohiro; Miura, Ayako; Nakagawa, Hikaru; Yanagita, Toshihiko; Takeya, Ryu; Tsuneyoshi, Isao.
Journal of Neuroscience Research 102 ( 10 ) e25386 2024
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Neuroscience Research
Voltage-gated sodium channels, including NaV1.7, NaV1.8, and NaV1.9, play important roles in pain transmission and chronic pain development. However, the specific mechanisms of their action remain unclear, highlighting the need for in vivo stimulation studies of these channels. Optogenetics, a novel technique for targeting the activation or inhibition of specific neural circuits using light, offers a promising solution. In our previous study, we used optogenetics to selectively excite NaV1.7-expressing neurons in the dorsal root ganglion of mice to induce nocifensive behavior. Here, we further characterize the impact of nocifensive behavior by activation of NaV1.7, NaV1.8, or NaV1.9-expressing neurons. Using CRISPR/Cas9-mediated homologous recombination, NaV1.7–iCre, NaV1.8–iCre, or NaV1.9–iCre mice expressing iCre recombinase under the control of the endogenous NaV1.7, NaV1.8, or NaV1.9 gene promoter were produced. These mice were then bred with channelrhodopsin-2 (ChR2) Cre–reporter Ai32 mice to obtain NaV1.7–ChR2, NaV1.8–ChR2, or NaV1.9–ChR2 mice. Blue light exposure triggered paw withdrawal in all mice, with the strongest response in NaV1.8–ChR2 mice. These light sensitivity differences observed across NaV1.x–ChR2 mice may be dependent on ChR2 expression or reflect the inherent disparities in their pain transmission roles. In conclusion, we have generated noninvasive pain models, with optically activated peripheral nociceptors. We believe that studies using optogenetics will further elucidate the role of sodium channel subtypes in pain transmission.
DOI： 10.1002/jnr.25386
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Effectiveness of Interprofessional Education Based on the Case-and Communication-Based Approach. Reviewed
武谷 立
IAFOR Journal of Psychology & the Behavioral Sciences 9 3 2024
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Koshida T., Maruta T., Tanaka N., Hidaka K., Kurogi M., Nemoto T., Yanagita T., Takeya R., Tsuneyoshi I.
Acta Medica Okayama 77 ( 4 ) 359 - 364 2023
Language：English Publishing type：Research paper (scientific journal) Publisher：Acta Medica Okayama
Pulsed radiofrequency (PRF) is a safe method of treating neuropathic pain by generating intermittent electric fields at the needle tip. Resiniferatoxin (RTX) is an ultrapotent agonist of transient receptor potential vanilloid subtype-1 (TRPV1) receptors. We investigated the mechanism of PRF using a rat model of RTX-induced neuropathic pain. After administering RTX intraperitoneally, PRF was applied to the right sciatic nerve. We observed the changes in TRPV1, calcitonin gene-related peptide (CGRP), and brain-derived neurotrophic factor (BDNF) in the dorsal root ganglia by western blotting. Expressions of TRPV1 and CGRP were significantly lower in the contralateral (RTX-treated, PRF-untreated) tissue than in control rats (p<0.0001 and p<0.0001, respectively) and the ipsilateral tissues (p<0.0001 and p<0.0001, respectively). BDNF levels were significantly higher in the contralateral tissues than in the control rats (p<0.0001) and the ipsilateral tissues (p<0.0001). These results suggest that, while TRPV1 and CGRP are decreased by RTX-induced neuronal damage, increased BDNF levels result in pain development. PRF may promote recovery from neuronal damage with concomitant restoration of TRPV1 and CGRP, and exert its analgesic effect by reversing BDNF increase. Further research is required to understand the role of TRPV1 and CGRP restoration in improving mechanical allodynia.
DOI： 10.18926/AMO/65741
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Selective optogenetic activation of NaV1.7-expressing afferents in NaV1.7-ChR2 mice induces nocifensive behavior without affecting responses to mechanical and thermal stimuli. Reviewed
Maruta T, Hidaka K, Kouroki S, Koshida T, Kurogi M, Kage Y, Mizuno S, Shirasaka T, Yanagita T, Takahashi S, Takeya R, Tsuneyoshi I
PloS one 17 ( 10 ) e0275751 2022.10
Language：English Publishing type：Research paper (scientific journal)
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Extracellular signal-regulated kinase phosphorylation enhancement and NaV1.7 sodium channel upregulation in rat dorsal root ganglia neurons contribute to resiniferatoxin-induced neuropathic pain: The efficacy and mechanism of pulsed radiofrequency therapy. Reviewed
Hidaka K, Maruta T, Koshida T, Kurogi M, Kage Y, Kouroki S, Shirasaka T, Takeya R, Tsuneyoshi I
Molecular pain 18 17448069221089784 2022.4
Language：English Publishing type：Research paper (scientific journal)
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Nursing pharmacology education and active-learning. Reviewed
Yanagita Toshihiko, Kanaoka Maki, Kinoshita Yumiko, Takeya Ryu
Folia Pharmacologica Japonica 157 ( 2 ) 104 - 109 2022.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Pharmacological Society
<p>Comprehensive pharmacology education in nursing based on the "Patient-oriented Pharmacology" is effective against the improvement of quality of pharmacotherapy and patient satisfaction. Two active learning programs of practical pharmacotherapy for nursing students have been performed in School of Nursing, University of Miyazaki; (1) pharmacotherapy role-play for interprofessional education (IPE) and (2) practical excise for Kampo medicine. Pharmacotherapy role-play for IPE was performed as joint lecture both medical students and nursing students. This pharmacotherapy role-play is named Case & Communication based approach (C&C approach), since it is studied through communication between physicians, nurses and patients based on cases presented beforehand. In the practical excise for Kampo medicine, nursing students studied Kampo medicines and tried to taste 9 frequently used Kampo medicines. These active-learning programs in nursing pharmacology education may be effective for better understanding of pharmacotherapy and patient's feeling, and improvement of students' motivation as a nurse.</p>
DOI： 10.1254/fpj.21100
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Differential effects of the formin inhibitor SMIFH2 on contractility and Ca2+ handling in frog and mouse cardiomyocytes Reviewed International journal
Koji Sakata, Sho Matsuyama, Nagomi Kurebayashi, Kengo Hayamizu, Takashi Murayama, Kunihide Nakamura, Kazuo Kitamura, Sachio Morimoto, Ryu Takeya
Genes to Cells 26 ( 8 ) 583 - 595 2021.8
Authorship：Last author, Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)
Genetic mutations in actin regulators have been emerging as a cause of cardiomyopathy, although the functional link between actin dynamics and cardiac contraction remains largely unknown. To obtain insight into this issue, we examined the effects of pharmacological inhibition of formins, a major class of actin-assembling proteins. The formin inhibitor SMIFH2 significantly enhanced the cardiac contractility of isolated frog hearts, thereby augmenting cardiac performance. SMIFH2 treatment had no significant effects on the Ca2+ sensitivity of frog muscle fibers. Instead, it unexpectedly increased Ca2+ concentrations of isolated frog cardiomyocytes, suggesting that the inotropic effect is due to enhanced Ca2+ transients. In contrast to frog hearts, the contractility of mouse cardiomyocytes was attenuated by SMIFH2 treatment with decreasing Ca2+ transients. Thus, SMIFH2 has opposing effects on the Ca2+ transient and contractility between frog and mouse cardiomyocytes. We further found that SMIFH2 suppressed Ca2+ -release via type 2 ryanodine receptor (RyR2); this inhibitory effect may explain the species differences, since RyR2 is critical for Ca2+ transients in mouse myocardium but absent in frog myocardium. Although the mechanisms underlying the enhancement of Ca2+ transients in frog cardiomyocytes remain unclear, SMIFH2 differentially affects the cardiac contraction of amphibian and mammalian by differentially modulating their Ca2+ handling.
DOI： 10.1111/gtc.12873
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Toyoaki Maruta, Takayuki Nemoto, Koutaro Hidaka, Tomohiro Koshida, Tetsuro Shirasaka, Toshihiko Yanagita, Ryu Takeya Isao Tsuneyoshi
PLoS ONE 14 ( 11 ) e0225586 2019.11
Language：English Publishing type：Research paper (scientific journal) Publisher：PLoS ONE
© 2019 Maruta et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Oxaliplatin is the first-line chemotherapy for metastatic colorectal cancer. Unlike other platinum anticancer agents, oxaliplatin does not result in significant renal impairment and ototoxicity. Oxaliplatin, however, has been associated with acute and chronic peripheral neuropathies. Despite the awareness of these side-effects, the underlying mechanisms are yet to be clearly established. Therefore, in this study, we aimed to understand the factors involved in the generation of chronic neuropathy elicited by oxaliplatin treatment. We established a rat model of oxaliplatin-induced neuropathic pain (4 mg kg-1 intraperitoneally). The paw withdrawal thresholds were assessed at different time-points after the treatment, and a significant decrease was observed 3 and 4 weeks after oxaliplatin treatment as compared to the vehicle treatment (4.4 ± 1.0 vs. 16.0 ± 4.1 g; P < 0.05 and 4.4 ± 0.7 vs. 14.8 ± 3.1 g; P < 0.05, respectively). We further evaluated the role of different mitogen-activated protein kinases (MAPKs) pathways in the pathophysiology of neuropathic pain. Although the levels of total extracellular signal-regulated kinase (ERK) 1/2 in the dorsal root ganglia (DRG) were not different between oxaliplatin and vehicle treatment groups, phosphorylated ERK (pERK) 1/2 was up-regulated up to 4.5-fold in the oxaliplatin group. Administration of ERK inhibitor PD98059 (6 μg day-1 intrathecally) inhibited oxaliplatin-induced ERK phosphorylation and neuropathic pain. Therefore, upregulation of p-ERK by oxaliplatin in rat DRG and inhibition of mechanical allodynia by an ERK inhibitor in the present study may provide a better understanding of intracellular molecular alterations associated with oxaliplatin-induced neuropathic pain and help in the development of potential therapeutics.
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Sanematsu F., Kanai A., Ushijima T., Shiraishi A., Abe T., Kage Y., Sumimoto H., Takeya R.
Cytoskeleton 76 ( 2 ) 219 - 229 2019.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Cytoskeleton
The formin family proteins have the ability to regulate actin filament assembly, thereby functioning in diverse cytoskeletal processes. Fhod3, a cardiac member of the family, plays a crucial role in development and functional maintenance of the heart. Although Fhod1, a protein closely-related to Fhod3, has been reported to be expressed in cardiomyocytes, the role of Fhod1 in the heart has still remained elusive. To know the physiological role of Fhod1 in the heart, we disrupted the Fhod1 gene in mice by replacement of exon 1 with a lacZ reporter gene. Histological lacZ staining unexpectedly revealed no detectable expression of Fhod1 in the heart, in contrast to intensive staining in the lung, a Fhod1-containing organ. Consistent with this, expression level of the Fhod1 protein in the heart was below the lower limit of detection of the present immunoblot analysis with three independent anti-Fhod1 antibodies. Homozygous Fhod1-null mice did not show any defects in gross and histological appearance of the heart or upregulate fetal cardiac genes that are induced under stress conditions. Furthermore, Fhod1 ablation did not elicit compensatory increase in expression of other formins. Thus, Fhod1 appears to be dispensable for normal development and function of the mouse heart, even if a marginal amount of Fhod1 is expressed in the heart.
DOI： 10.1002/cm.21523
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Fujimoto N., Kan-O M., Ushijima T., Kage Y., Tominaga R., Sumimoto H., Takeya R.
PLoS ONE 11 ( 2 ) e0148472 2016.2
Language：English Publishing type：Research paper (scientific journal) Publisher：PLoS ONE
© 2016 Fujimoto et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Fhod3 is a cardiac member of the formin family proteins that play pivotal roles in actin filament assembly in various cellular contexts. The targeted deletion of mouse Fhod3 gene leads to defects in cardiogenesis, particularly during myofibrillogenesis, followed by lethality at embryonic day (E) 11.5. However, it remains largely unknown how Fhod3 functions during myofibrillogenesis. In this study, to assess the mechanism whereby Fhod3 regulates myofibrillogenesis during embryonic cardiogenesis, we generated transgenic mice expressing Fhod3 selectively in embryonic cardiomyocytes under the control of the β-myosin heavy chain (MHC) promoter. Mice expressing wild-Type Fhod3 in embryonic cardiomyocytes survive to adulthood and are fertile, whereas those expressing Fhod3 (I1127A) defective in binding to actin die by E11.5 with cardiac defects. This cardiac phenotype of the Fhod3 mutant embryos is almost identical to that observed in Fhod3 null embryos, suggesting that the actin-binding activity of Fhod3 is crucial for embryonic cardiogenesis. On the other hand, the β-MHC promoter-driven expression of wild-Type Fhod3 sufficiently rescues cardiac defects of Fhod3-null embryos, indicating that the Fhod3 protein expressed in a transgenic manner can function properly to achieve myofibril maturation in embryonic cardiomyocytes. Using the transgenic mice, we further examined detailed localization of Fhod3 during myofibrillogenesis in situ and found that Fhod3 localizes to the specific central region of nascent sarcomeres prior to massive rearrangement of actin filaments and remains there throughout myofibrillogenesis. Taken together, the present findings suggest that, during embryonic cardiogenesis, Fhod3 functions as the essential reorganizer of actin filaments at the central region of maturating sarcomeres via the actin-binding activity of the FH2 domain.
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心筋の収縮装置「サルコメア」の形成の分子機構
武谷 立
生存科学 J.Seizon and Life Sci 26 ( 1 ) 299 - 305 2015.9
Language：English Publishing type：Research paper (scientific journal)
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Yanagita Toshihiko, Nemoto Takayuki, Takeya Ryu
Folia Pharmacologica Japonica 146 ( 2 ) 115 - 8 2015.8
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Pharmacological Society
DOI： 10.1254/fpj.146.115
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Novel human homologues of p47phox and p67phox participate in activation of superoxide-producing NADPH oxidases.
Takeya R, Ueno N, Kami K, Taura M, Kohjima M, Izaki T, Nunoi H, Sumimoto H
The Journal of biological chemistry 290 ( 10 ) 6003 2015.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Arimura T., Takeya R., Ishikawa T., Yamano T., Matsuo A., Tatsumi T., Nomura T., Sumimoto H., Kimura A.
Circulation Journal 77 ( 12 ) 2990 - 2996 2013.11
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Circulation Journal
Background: Dilated cardiomyopathy (DCM) is characterized by a dilated left ventricular cavity with systolic dysfunction manifested by heart failure. It has been revealed that mutations in genes for cytoskeleton or sarcomere proteins cause DCM. However, the disease-causing mutations can be found only in far less than half of patients with a family history, indicating that there should be other disease genes for DCM. Formin homology 2 domain containing 3 (FHOD3) is a sarcomeric protein expressed in the heart that plays an essential role in sarcomere organization during myofibrillogenesis. The purpose of this study was to explore a possible novel disease gene for DCM. Methods and Results: We analyzed 48 Japanese familial DCM patients for mutations in FHOD3, and a missense variant, Tyr1249Asn, which was predicted to modify the 3D structure and damage protein function, was found in a case with adult-onset DCM. Functional studies revealed that the DCM-associated mutation significantly reduced the ability to induce actin dynamics-dependent activation of serum response factor, although no remarkable change in the cellular localization was induced in neonatal rat cardiomyocytes transfected with a mutant construct of FHOD3. Conclusions: The DCM-associated FHOD3 variant may cause DCM by interfering with actin filament assembly.