1
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Lopriore P, Vista M, Maritato P, Caldarazzo Ienco E, Bassani L, Natale G, Tessa A, Santorelli FM, Orsucci D. Deep neurological phenotyping in oculo-dento-digital syndrome. Neurol Sci 2024; 45:2853-2857. [PMID: 38253744 DOI: 10.1007/s10072-024-07331-z] [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: 12/05/2023] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
OBJECTIVES Oculodentodigital dysplasia (ODDD) is a rare autosomal dominant congenital malformation syndrome characterized by high penetrance and great phenotypic heterogeneity. Neurological manifestations are thought to occur in about one third of cases, but systematic studies are not available. We performed deep neurological phenotyping of 10 patients in one ODDD pedigree. METHODS Retrospective case series. We analyzed in depth the neurological phenotype of a three-generation family segregating the heterozygous c.416 T > C, p.(Ile139Thr) in GJA1. Clinical and neuroradiological features were retrospectively evaluated. Brain MRI and visual evoked potentials were performed in 8 and 6 cases, respectively. RESULTS Central nervous system manifestations occurred in 5 patients, the most common being isolated ataxia either in isolation or combined with spasticity. Furthermore, sphincteric disturbances (neurogenic bladder and fecal incontinence) were recognized as the first manifestation in most of the patients. Subclinical electrophysiological alteration of the optic pathway occurred in all the examined patients. Neuroimaging was significant for supratentorial hypomyelination pattern and hyperintense superior cerebellar peduncle in all examined patients. CONCLUSION The neurological involvement in ODDD carriers is often missed but peculiar clinical and radiological patterns can be recognized. Deep neurological phenotyping is needed to help untangle ODDD syndrome complexity and find genotype-phenotype correlations.
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Affiliation(s)
- P Lopriore
- Unit of Neurology, San Luca Hospital, Lucca, Italy
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - M Vista
- Unit of Neurology, San Luca Hospital, Lucca, Italy
| | - P Maritato
- Unit of Neurology, San Luca Hospital, Lucca, Italy
| | | | - L Bassani
- Unit of Radiology, San Luca Hospital, Lucca, Italy
| | - G Natale
- Molecular Medicine, IRCCS Stella Maris Foundation, Pisa, Italy
| | - A Tessa
- Molecular Medicine, IRCCS Stella Maris Foundation, Pisa, Italy
| | - F M Santorelli
- Molecular Medicine, IRCCS Stella Maris Foundation, Pisa, Italy
| | - D Orsucci
- Unit of Neurology, San Luca Hospital, Lucca, Italy.
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2
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Batissoco AC, Cruz DB, Alegria TGP, Kobayashi G, Oiticica J, Soares LE, Passos-Bueno MR, Haddad LA, Mingroni RC. GJB2 c.35del variant up-regulates GJA1 gene expression and affects differentiation of human stem cells. Genet Mol Biol 2024; 47:e20230170. [PMID: 38626573 PMCID: PMC11021044 DOI: 10.1590/1678-4685-gmb-2023-0170] [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: 06/02/2023] [Accepted: 01/17/2024] [Indexed: 04/18/2024] Open
Abstract
Pathogenic DNA alterations in GJB2 are present in nearly half of non-syndromic hearing loss cases with autosomal recessive inheritance. The most frequent variant in GJB2 causing non-syndromic hearing loss is the frameshifting c.35del. GJB2 encodes Cx26, a protein of the connexin family that assembles hemichannels and gap junctions. The expression of paralogous proteins is believed to compensate for the loss of function of specific connexins. As Cx26 has been involved in cell differentiation in distinct tissues, we employed stem cells derived from human exfoliated deciduous teeth (SHEDs), homozygous for the c.35del variant, to assess GJB2 roles in stem cell differentiation and the relationship between its loss of function and the expression of paralogous genes. Primary SHED cultures from patients and control individuals were compared. SHEDs from patients had significantly less GJB2 mRNA and increased amount of GJA1 (Cx43), but not GJB6 (Cx30) or GJB3 (Cx31) mRNA. In addition, they presented higher induced differentiation to adipocytes and osteocytes but lower chondrocyte differentiation. Our results suggest that GJA1 increased expression may be involved in functional compensation for GJB2 loss of function in human stem cells, and it may explain changes in differentiation properties observed in SHEDs with and without the c.35del variant.
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Affiliation(s)
- Ana Carla Batissoco
- Universidade de São Paulo (USP), Faculdade de Medicina (FM), Hospital das Clínicas (HC), Laboratório de Investigação Médica de Otorrinolaringologia (LIM32), São Paulo, SP, Brazil
- Universidade de São Paulo (USP), Faculdade de Medicina (FM), Departamento de Otorrinolaringologia, São Paulo, SP, Brazil
| | - Dayane Bernardino Cruz
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Thiago Geronimo Pires Alegria
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Gerson Kobayashi
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Jeanne Oiticica
- Universidade de São Paulo (USP), Faculdade de Medicina (FM), Hospital das Clínicas (HC), Laboratório de Investigação Médica de Otorrinolaringologia (LIM32), São Paulo, SP, Brazil
- Universidade de São Paulo (USP), Faculdade de Medicina (FM), Departamento de Otorrinolaringologia, São Paulo, SP, Brazil
| | - Luis Eduardo Soares
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Maria Rita Passos-Bueno
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Luciana Amaral Haddad
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
| | - Regina Célia Mingroni
- Universidade de São Paulo (USP), Instituto de Biociências (IB), Centro de Pesquisa Sobre o Genoma Humano e Células-Tronco (HUG-CELL), Departamento de Genética e Biologia Evolutiva, São Paulo, SP, Brazil
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3
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Fujii Y, Okabe I, Hatori A, Sah SK, Kanaujiya J, Fisher M, Norris R, Terasaki M, Reichenberger EJ, Chen IP. Skeletal abnormalities caused by a Connexin43 R239Q mutation in a mouse model for autosomal recessive craniometaphyseal dysplasia. RESEARCH SQUARE 2024:rs.3.rs-3906170. [PMID: 38405920 PMCID: PMC10889043 DOI: 10.21203/rs.3.rs-3906170/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Craniometaphyseal dysplasia (CMD), a rare craniotubular disorder, occurs in an autosomal dominant (AD) or autosomal recessive (AR) form. CMD is characterized by hyperostosis of craniofacial bones and flaring metaphyses of long bones. Many patients with CMD suffer from neurological symptoms. To date, the pathogenesis of CMD is not fully understood. Treatment is limited to decompression surgery. Here, we report a knock in (KI) mouse model for AR CMD carrying a R239Q mutation in CX43. Cx43KI/KI mice replicate many features of AR CMD in craniofacial and long bones. In contrast to Cx43+/+ littermates, Cx43KI/KI mice exhibit periosteal bone deposition and increased osteoclast (OC) numbers in the endosteum of long bones, leading to an expanded bone marrow cavity and increased cortical bone thickness. Although formation of Cx43+/+ and Cx43KI/KI resting OCs are comparable, on bone chips the actively resorbing Cx43KI/KI OCs resorb less bone. Cortical bones of Cx43KI/KI mice have an increase in degenerating osteocytes and empty lacunae. Osteocyte dendrite formation is decreased with reduced expression levels of Fgf23, Sost, Tnf-α, IL-1β, Esr1, Esr2, and a lower Rankl/Opg ratio. Female Cx43KI/KI mice display a more severe phenotype. Sexual dimorphism in bone becomes more evident as mice age. Our data show that the CX43R239Q mutation results in mislocalization of CX43 protein and impairment of gap junction and hemichannel activity. Different from CX43 ablation mouse models, the CX43R239Q mutation leads to the AR CMD-like phenotype in Cx43KI/KI mice not only by loss-of-function but also via a not yet revealed dominant function.
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Affiliation(s)
- Yasuyuki Fujii
- Department of Endodontology, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Iichiro Okabe
- Department of Endodontology, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Ayano Hatori
- Department of Endodontology, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Shyam Kishor Sah
- Department of Endodontology, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
| | - Jitendra Kanaujiya
- Department of Cell Biology, University of Connecticut Health, Farmington, CT, United States
| | - Melanie Fisher
- Department of Cell Biology, University of Connecticut Health, Farmington, CT, United States
| | - Rachael Norris
- Department of Cell Biology, University of Connecticut Health, Farmington, CT, United States
| | - Mark Terasaki
- Department of Cell Biology, University of Connecticut Health, Farmington, CT, United States
| | - Ernst J. Reichenberger
- Center for Regenerative Medicine and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
| | - I-Ping Chen
- Department of Endodontology, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
- Center for Regenerative Medicine and Skeletal Development, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States
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Shimomura R, Yanagishita T, Ishiguro K, Shichiji M, Sato T, Shimojima Yamamoto K, Nagata M, Ishihara Y, Miyashita Y, Ishigaki K, Nagata S, Asano Y, Yamamoto T. Rare mosaic variant of GJA1 in a patient with a neurodevelopmental disorder. Hum Genome Var 2024; 11:2. [PMID: 38221519 PMCID: PMC10788341 DOI: 10.1038/s41439-023-00262-9] [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: 10/19/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 01/16/2024] Open
Abstract
GJA1 is the causative gene for oculodentodigital dysplasia (ODDD). A novel de novo GJA1 variant, NM 000165:c263C > T [p.P88L], was identified in a mosaic state in a patient with short stature, seizures, delayed myelination, mild hearing loss, and tooth enamel hypoplasia. Although the patient exhibited severe neurodevelopmental delay, other clinical features of ODDD, including limb anomalies, were mild. This may be due to differences in the mosaic ratios in different organs.
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Affiliation(s)
- Rina Shimomura
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan
| | - Tomoe Yanagishita
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Kumiko Ishiguro
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Minobu Shichiji
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Takatoshi Sato
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Keiko Shimojima Yamamoto
- Transfusion Medicine and Cell Processing, Tokyo Women's Medical University, Tokyo, Japan
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Miho Nagata
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yasuki Ishihara
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yohei Miyashita
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
- Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Keiko Ishigaki
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Satoru Nagata
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Yoshihiro Asano
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
- Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Toshiyuki Yamamoto
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan.
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan.
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5
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Lavriha P, Qi C, Korkhov VM. Expression, Purification, and Nanodisc Reconstitution of Connexin-43 Hemichannels for Structural Characterization by Cryo-Electron Microscopy. Methods Mol Biol 2024; 2801:29-43. [PMID: 38578411 DOI: 10.1007/978-1-0716-3842-2_3] [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] [Indexed: 04/06/2024]
Abstract
Connexins are polytopic domain membrane proteins that form hexameric hemichannels (HCs) which can assemble into gap junction channels (GJCs) at the interface of two neighboring cells. The HCs may be involved in ion and small-molecule transport across the cellular plasma membrane in response to various stimuli. Despite their importance, relatively few structures of connexin HCs are available to date, compared to the structures of the GJCs. Here, we describe a protocol for expression, purification, and nanodisc reconstitution of connexin-43 (Cx43) HCs, which we have recently structurally characterized using cryo-EM analysis. Application of similar protocols to other connexin family members will lead to breakthroughs in the understanding of the structure and function of connexin HCs.
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Affiliation(s)
- Pia Lavriha
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Chao Qi
- Institute of Molecular Biology and Biophysics, ETH, Zurich, Switzerland
| | - Volodymyr M Korkhov
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland.
- Institute of Molecular Biology and Biophysics, ETH, Zurich, Switzerland.
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6
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Lukowicz-Bedford RM, Eisen JS, Miller AC. Gap junction mediated bioelectric coordination is required for slow muscle development, organization, and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572619. [PMID: 38187655 PMCID: PMC10769300 DOI: 10.1101/2023.12.20.572619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Bioelectrical signaling, intercellular communication facilitated by membrane potential and electrochemical coupling, is emerging as a key regulator of animal development. Gap junction (GJ) channels can mediate bioelectric signaling by creating a fast, direct pathway between cells for the movement of ions and other small molecules. In vertebrates, GJ channels are formed by a highly conserved transmembrane protein family called the Connexins. The connexin gene family is large and complex, presenting a challenge in identifying the specific Connexins that create channels within developing and mature tissues. Using the embryonic zebrafish neuromuscular system as a model, we identify a connexin conserved across vertebrate lineages, gjd4, which encodes the Cx46.8 protein, that mediates bioelectric signaling required for appropriate slow muscle development and function. Through a combination of mutant analysis and in vivo imaging we show that gjd4/Cx46.8 creates GJ channels specifically in developing slow muscle cells. Using genetics, pharmacology, and calcium imaging we find that spinal cord generated neural activity is transmitted to developing slow muscle cells and synchronized activity spreads via gjd4/Cx46.8 GJ channels. Finally, we show that bioelectrical signal propagation within the developing neuromuscular system is required for appropriate myofiber organization, and that disruption leads to defects in behavior. Our work reveals the molecular basis for GJ communication among developing muscle cells and reveals how perturbations to bioelectric signaling in the neuromuscular system_may contribute to developmental myopathies. Moreover, this work underscores a critical motif of signal propagation between organ systems and highlights the pivotal role played by GJ communication in coordinating bioelectric signaling during development.
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7
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Yamasaki R. Connexins Control Glial Inflammation in Various Neurological Diseases. Int J Mol Sci 2023; 24:16879. [PMID: 38069203 PMCID: PMC10706219 DOI: 10.3390/ijms242316879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/25/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Connexins (Cxs) form gap junctions through homotypic/heterotypic oligomerization. Cxs are initially synthesized in the endoplasmic reticulum, then assembled as hexamers in the Golgi apparatus before being integrated into the cell membrane as hemichannels. These hemichannels remain closed until they combine to create gap junctions, directly connecting neighboring cells. Changes in the intracellular or extracellular environment are believed to trigger the opening of hemichannels, creating a passage between the inside and outside of the cell. The size of the channel pore depends on the Cx isoform and cellular context-specific effects such as posttranslational modifications. Hemichannels allow various bioactive molecules, under ~1 kDa, to move in and out of the host cell in the direction of the electrochemical gradient. In this review, we explore the fundamental roles of Cxs and their clinical implications in various neurological dysfunctions, including hereditary diseases, ischemic brain disorders, degenerative conditions, demyelinating disorders, and psychiatric illnesses. The influence of Cxs on the pathomechanisms of different neurological disorders varies depending on the circumstances. Hemichannels are hypothesized to contribute to proinflammatory effects by releasing ATP, adenosine, glutamate, and other bioactive molecules, leading to neuroglial inflammation. Modulating Cxs' hemichannels has emerged as a promising therapeutic approach.
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Affiliation(s)
- Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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8
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Hoppock GA, Buettmann EG, Denisco JA, Goldscheitter GM, Condyles SN, Juhl OJ, Friedman MA, Zhang Y, Donahue HJ. Connexin 43 and cell culture substrate differentially regulate OCY454 osteocytic differentiation and signaling to primary bone cells. Am J Physiol Cell Physiol 2023; 325:C907-C920. [PMID: 37602413 PMCID: PMC10635658 DOI: 10.1152/ajpcell.00220.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/22/2023]
Abstract
Connexin 43 (Cx43), the predominate gap junction protein in bone, is essential for intercellular communication and skeletal homeostasis. Previous work suggests that osteocyte-specific deletion of Cx43 leads to increased bone formation and resorption; however, the cell-autonomous role of osteocytic Cx43 in promoting increased bone remodeling is unknown. Recent studies using three-dimensional (3D) culture substrates in OCY454 cells suggest that 3D cultures may offer increased bone remodeling factor expression and secretion, such as sclerostin and receptor activator of nuclear factor-κB ligand (RANKL). In this study, we compared culturing OCY454 osteocytes on 3D Alvetex scaffolds with traditional 2D tissue culture, both with [wild-type (WT)] and without Cx43 (Cx43 KO). Conditioned media from OCY454 cell cultures were used to determine soluble signaling to differentiate primary bone marrow cells into osteoblasts and osteoclasts. OCY454 cells cultured on 3D portrayed a mature osteocytic phenotype, relative to cells on 2D, shown by increased osteocytic gene expression and reduced cell proliferation. In contrast, OCY454 differentiation based on these same markers was not affected by Cx43 deficiency in 3D. Interestingly, increased sclerostin secretion was found in 3D cultured WT cells compared with that of Cx43 KO cells. Conditioned media from Cx43 KO cells promoted increased osteoblastogenesis and osteoclastogenesis, with maximal effects from 3D cultured Cx43 KO cells. These results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Finally, 3D cultures appear better suited to study mechanisms from Cx43-deficient OCY454 osteocytes in vitro due to their ability to promote osteocyte differentiation, limit proliferation, and increase bone remodeling factor secretion.NEW & NOTEWORTHY 3D cell culture of OCY454 cells promoted increased differentiation compared with traditional 2D culture. Although Cx43 deficiency did not affect OCY454 differentiation, it resulted in increased signaling, promoting osteoblastogenesis and osteoclastogenesis. Our results suggest that Cx43 deficiency promotes increased bone remodeling in a cell-autonomous manner with minimal changes in osteocyte differentiation. Also, 3D cultures appear better suited to study mechanisms in Cx43-deficient OCY454 osteocytes.
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Affiliation(s)
- Gabriel A Hoppock
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Evan G Buettmann
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Joseph A Denisco
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Galen M Goldscheitter
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Sebastian N Condyles
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Otto J Juhl
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Michael A Friedman
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Yue Zhang
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
| | - Henry J Donahue
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, Virginia, United States
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Dong J, Ruan W, Duan X. Molecular-based phenotype variations in amelogenesis imperfecta. Oral Dis 2023; 29:2334-2365. [PMID: 37154292 DOI: 10.1111/odi.14599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 04/03/2023] [Accepted: 04/15/2023] [Indexed: 05/10/2023]
Abstract
Amelogenesis imperfecta (AI) is one of the typical dental genetic diseases in human. It can occur isolatedly or as part of a syndrome. Previous reports have mainly clarified the types and mechanisms of nonsyndromic AI. This review aimed to compare the phenotypic differences among the hereditary enamel defects with or without syndromes and their underlying pathogenic genes. We searched the articles in PubMed with different strategies or keywords including but not limited to amelogenesis imperfecta, enamel defects, hypoplastic/hypomaturation/hypocalcified, syndrome, or specific syndrome name. The articles with detailed clinical information about the enamel and other phenotypes and clear genetic background were used for the analysis. We totally summarized and compared enamel phenotypes of 18 nonsyndromic AI with 17 causative genes and 19 syndromic AI with 26 causative genes. According to the clinical features, radiographic or ultrastructural changes in enamel, the enamel defects were basically divided into hypoplastic and hypomineralized (hypomaturated and hypocalcified) and presented a higher heterogeneity which were closely related to the involved pathogenic genes, types of mutation, hereditary pattern, X chromosome inactivation, incomplete penetrance, and other mechanisms.The gene-specific enamel phenotypes could be an important indicator for diagnosing nonsyndromic and syndromic AI.
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Affiliation(s)
- Jing Dong
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
- College of Life Sciences, Northwest University, Xi'an, China
| | - Wenyan Ruan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
| | - Xiaohong Duan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
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10
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Plotkin LI, Asad I, Kritikos AE, Sanz N. Role of Cx43 on the Bone Cell Generation, Function, and Survival. Bioelectricity 2023; 5:188-195. [PMID: 37746312 PMCID: PMC10517329 DOI: 10.1089/bioe.2023.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023] Open
Abstract
The presence of gap junction intercellular communication structures in bone cells has been known since the early 1970s, further confirmed by Doty and Marotti at the structural level in the 1980-1990s. Work by Civitelli, Donahue, and others showed the expression of Cx43 at the mRNA and protein levels in all bone cell types: osteoclasts (bone resorbing cells), osteoblasts (bone forming cells), and osteocytes (mature osteoblasts embedded in the bone matrix that regulate the function of both osteoclasts and osteoblasts). While Cx45, Cx46, and Cx37 were also shown to be expressed in bone cells, most studies have focused on Cx43, the most abundant member of the connexin (Cx) family of proteins expressed in bone. The role of Cx43 has been shown to be related to the formation of gap junction intercellular channels, to unopposed hemichannels, and to channel independent functions of the molecule. Cx43 participates in the response of bone cells to pharmacological, hormonal, and mechanical stimuli, and it is involved in the skeletal phenotype with old age. Human and murine studies have shown that mutations of Cx43 lead to oculodentodigital dysplasia and craniometaphyseal dysplasia, both conditions associated with abnormalities in the skeleton. However, whereas substantial advances have been made on the skeletal role of Cx43, further research is needed to understand the basis for the effects of mutated Cx43 and potential ways to prevent the effects of these mutations on bone.
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Affiliation(s)
- Lilian I. Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, USA
- Indiana Center for Musculoskeletal Health, Indianapolis, Indiana, USA
| | - Iqra Asad
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Alex E. Kritikos
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Natasha Sanz
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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11
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Hoppock GA, Buettmann EG, Denisco JA, Goldscheitter GM, Condyles SN, Juhl OJ, Friedman MA, Zhang Y, Donahue HJ. Connexin 43 and Cell Culture Substrate Differentially Regulate OCY454 Osteocytic Differentiation and Signaling to Primary Bone Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.23.546276. [PMID: 37425674 PMCID: PMC10326966 DOI: 10.1101/2023.06.23.546276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Connexin 43 (Cx43), the predominate gap junction protein in bone, is essential for intercellular communication and skeletal homeostasis. Previous work suggests osteocyte-specific deletion of Cx43 leads to increased bone formation and resorption, however the cell-autonomous role of osteocytic Cx43 in promoting increased bone remodeling is unknown. Recent studies using 3D culture substrates in OCY454 cells suggest 3D cultures may offer increased bone remodeling factor expression and secretion, such as sclerostin and RANKL. In this study, we compared culturing OCY454 osteocytes on 3D Alvetex scaffolds to traditional 2D tissue culture, both with (WT) and without Cx43 (Cx43 KO). Conditioned media from OCY454 cell cultures was used to determine soluble signaling to differentiate primary bone marrow stromal cells into osteoblasts and osteoclasts. OCY454 cells cultured on 3D portrayed a mature osteocytic phenotype, relative to cells on 2D, shown by increased osteocytic gene expression and reduced cell proliferation. In contrast, OCY454 differentiation based on these same markers was not affected by Cx43 deficiency in 3D. Interestingly, increased sclerostin secretion was found in 3D cultured WT cells compared to Cx43 KO cells. Conditioned media from Cx43 KO cells promoted increased osteoblastogenesis and increased osteoclastogenesis, with maximal effects from 3D cultured Cx43 KO cells. These results suggest Cx43 deficiency promotes increased bone remodeling in a cell autonomous manner with minimal changes in osteocyte differentiation. Finally, 3D cultures appear better suited to study mechanisms from Cx43-deficient OCY454 osteocytes in vitro due to their ability to promote osteocyte differentiation, limit proliferation, and increase bone remodeling factor secretion. New and Noteworthy 3D cell culture of OCY454 cells promoted increased differentiation compared to traditional 2D culture. While Cx43 deficiency did not affect OCY454 differentiation, it resulted in increased signaling, promoting osteoblastogenesis and osteoclastogenesis. Our results suggest Cx43 deficiency promotes increased bone remodeling in a cell autonomous manner with minimal changes in osteocyte differentiation. Also, 3D cultures appear better suited to study mechanisms in Cx43-deficient OCY454 osteocytes.
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12
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Abrams CK. Mechanisms of Diseases Associated with Mutation in GJC2/Connexin 47. Biomolecules 2023; 13:biom13040712. [PMID: 37189458 DOI: 10.3390/biom13040712] [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: 03/11/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/17/2023] Open
Abstract
Connexins are members of a family of integral membrane proteins that provide a pathway for both electrical and metabolic coupling between cells. Astroglia express connexin 30 (Cx30)-GJB6 and Cx43-GJA1, while oligodendroglia express Cx29/Cx31.3-GJC3, Cx32-GJB1, and Cx47-GJC2. Connexins organize into hexameric hemichannels (homomeric if all subunits are identical or heteromeric if one or more differs). Hemichannels from one cell then form cell-cell channels with a hemichannel from an apposed cell. (These are termed homotypic if the hemichannels are identical and heterotypic if the hemichannels differ). Oligodendrocytes couple to each other through Cx32/Cx32 or Cx47/Cx47 homotypic channels and they couple to astrocytes via Cx32/Cx30 or Cx47/Cx43 heterotypic channels. Astrocytes couple via Cx30/Cx30 and Cx43/Cx43 homotypic channels. Though Cx32 and Cx47 may be expressed in the same cells, all available data suggest that Cx32 and Cx47 cannot interact heteromerically. Animal models wherein one or in some cases two different CNS glial connexins have been deleted have helped to clarify the role of these molecules in CNS function. Mutations in a number of different CNS glial connexin genes cause human disease. Mutations in GJC2 lead to three distinct phenotypes, Pelizaeus Merzbacher like disease, hereditary spastic paraparesis (SPG44) and subclinical leukodystrophy.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
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13
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Zhao D, Wu J, Acosta FM, Xu H, Jiang JX. Connexin 43 hemichannels and prostaglandin E 2 release in anabolic function of the skeletal tissue to mechanical stimulation. Front Cell Dev Biol 2023; 11:1151838. [PMID: 37123401 PMCID: PMC10133519 DOI: 10.3389/fcell.2023.1151838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
Bone adapts to changes in the physical environment by modulating remodeling through bone resorption and formation to maintain optimal bone mass. As the most abundant connexin subtype in bone tissue, connexin 43 (Cx43)-forming hemichannels are highly responsive to mechanical stimulation by permitting the exchange of small molecules (<1.2 kDa) between bone cells and the extracellular environment. Upon mechanical stimulation, Cx43 hemichannels facilitate the release of prostaglandins E2 (PGE2), a vital bone anabolic factor from osteocytes. Although most bone cells are involved in mechanosensing, osteocytes are the principal mechanosensitive cells, and PGE2 biosynthesis is greatly enhanced by mechanical stimulation. Mechanical stimulation-induced PGE2 released from osteocytic Cx43 hemichannels acts as autocrine effects that promote β-catenin nuclear accumulation, Cx43 expression, gap junction function, and protects osteocytes against glucocorticoid-induced osteoporosis in cultured osteocytes. In vivo, Cx43 hemichannels with PGE2 release promote bone formation and anabolism in response to mechanical loading. This review summarizes current in vitro and in vivo understanding of Cx43 hemichannels and extracellular PGE2 release, and their roles in bone function and mechanical responses. Cx43 hemichannels could be a significant potential new therapeutic target for treating bone loss and osteoporosis.
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Affiliation(s)
- Dezhi Zhao
- School of Medicine, Northwest University, Xi’an, China
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jiawei Wu
- School of Medicine, Northwest University, Xi’an, China
| | - Francisca M. Acosta
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Huiyun Xu
- School of Life Sciences, Northwestern Polytechnical University, Xi’an, China
| | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, United States
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14
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Perrier S, Guerrero K, Tran LT, Michell-Robinson MA, Legault G, Brais B, Sylvain M, Dorman J, Demos M, Köhler W, Pastinen T, Thiffault I, Bernard G. Solving inherited white matter disorder etiologies in the neurology clinic: Challenges and lessons learned using next-generation sequencing. Front Neurol 2023; 14:1148377. [PMID: 37077564 PMCID: PMC10108901 DOI: 10.3389/fneur.2023.1148377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 02/23/2023] [Indexed: 04/05/2023] Open
Abstract
IntroductionRare neurodevelopmental disorders, including inherited white matter disorders or leukodystrophies, often present a diagnostic challenge on a genetic level given the large number of causal genes associated with a range of disease subtypes. This study aims to demonstrate the challenges and lessons learned in the genetic investigations of leukodystrophies through presentation of a series of cases solved using exome or genome sequencing.MethodsEach of the six patients had a leukodystrophy associated with hypomyelination or delayed myelination on MRI, and inconclusive clinical diagnostic genetic testing results. We performed next generation sequencing (case-based exome or genome sequencing) to further investigate the genetic cause of disease.ResultsFollowing different lines of investigation, molecular diagnoses were obtained for each case, with patients harboring pathogenic variants in a range of genes including TMEM106B, GJA1, AGA, POLR3A, and TUBB4A. We describe the lessons learned in reaching the genetic diagnosis, including the importance of (a) utilizing proper multi-gene panels in clinical testing, (b) assessing the reliability of biochemical assays in supporting diagnoses, and (c) understanding the limitations of exome sequencing methods in regard to CNV detection and region coverage in GC-rich areas.DiscussionThis study illustrates the importance of applying a collaborative diagnostic approach by combining detailed phenotyping data and metabolic results from the clinical environment with advanced next generation sequencing analysis techniques from the research environment to increase the diagnostic yield in patients with genetically unresolved leukodystrophies.
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Affiliation(s)
- Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kether Guerrero
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Luan T. Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Mackenzie A. Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Geneviève Legault
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Michel Sylvain
- Division of Pediatric Neurology, Centre Mère-Enfant Soleil du CHU de Québec - Université Laval, Québec City, QC, Canada
| | - James Dorman
- John H. Stroger Jr. Hospital of Cook County, Chicago, IL, United States
- Department of Neurological Sciences, Rush Medical College, Chicago, IL, United States
| | - Michelle Demos
- Division of Neurology, Department of Pediatrics, University of British Columbia, BC Children's Hospital, Vancouver, BC, Canada
| | - Wolfgang Köhler
- Leukodystrophy Center, University of Leipzig Medical Center, Leipzig, Germany
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, United States
- Isabelle Thiffault
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- *Correspondence: Geneviève Bernard
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15
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Hindu KD, Umer F. Oculo-dento-digital dysplasia: a systematic analysis of published dental literature. BDJ Open 2023; 9:13. [PMID: 36990989 DOI: 10.1038/s41405-023-00139-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 03/06/2023] [Indexed: 03/31/2023] Open
Abstract
INTRODUCTION Oculo-dento-digital dysplasia (ODDD, OMIM# 164200) is a rare genetic disorder caused by mutation in Gap junction alpha gene that encodes connexin 43 (Cx43) protein. In this paper, the case of a 16-year-old boy is reported who presented with the complaint of toothache. Examination revealed unusual facial features, i.e., long narrow nose, hypertelorism, prominent epicanthal folds along with syndactyly and camptodactyly. We have also compiled available dental literature on ODDD that will help clinicians in early diagnosis and management of this condition. MATERIALS AND METHODS A literature search was performed in PubMed NLM, EBSCO Dentistry & Oral Sciences Source, and EBSCO CINAHL Plus. RESULTS A total of 309 articles were identified in the literature search. Only 17 articles were included based on the predetermined inclusion and exclusion criteria in the review synthesis. The included articles were case reports (n = 15), a case report and review (n = 1), and an original article (n = 1). Enamel hypoplasia, hypomineralization, microdontia, pulp stones, curved roots, and taurodontism were common dental findings in ODDD. CONCLUSIONS After establishing definitive diagnosis, a multidisciplinary team should work in cohesion to improve the quality of life of patients. Immediate treatment should be focused on the correction of current oral condition and symptomatic treatment. In the long term, attention should be diverted to prevent tooth wear and maintaining the occlusal vertical dimension to establish adequate function.
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Affiliation(s)
| | - Fahad Umer
- Aga Khan University Hospital, Stadium Road, Karachi, 74800, Pakistan.
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16
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Leybaert L, De Smet MA, Lissoni A, Allewaert R, Roderick HL, Bultynck G, Delmar M, Sipido KR, Witschas K. Connexin hemichannels as candidate targets for cardioprotective and anti-arrhythmic treatments. J Clin Invest 2023; 133:168117. [PMID: 36919695 PMCID: PMC10014111 DOI: 10.1172/jci168117] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023] Open
Abstract
Connexins are crucial cardiac proteins that form hemichannels and gap junctions. Gap junctions are responsible for the propagation of electrical and chemical signals between myocardial cells and cells of the specialized conduction system in order to synchronize the cardiac cycle and steer cardiac pump function. Gap junctions are normally open, while hemichannels are closed, but pathological circumstances may close gap junctions and open hemichannels, thereby perturbing cardiac function and homeostasis. Current evidence demonstrates an emerging role of hemichannels in myocardial ischemia and arrhythmia, and tools are now available to selectively inhibit hemichannels without inhibiting gap junctions as well as to stimulate hemichannel incorporation into gap junctions. We review available experimental evidence for hemichannel contributions to cellular pro-arrhythmic events in ventricular and atrial cardiomyocytes, and link these to insights at the level of molecular control of connexin-43-based hemichannel opening. We conclude that a double-edged approach of both preventing hemichannel opening and preserving gap junctional function will be key for further research and development of new connexin-based experimental approaches for treating heart disease.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Maarten Aj De Smet
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Alessio Lissoni
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Rosalie Allewaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mario Delmar
- Leon H. Charney Division of Cardiology, School of Medicine, New York University, New York, USA
| | - Karin R Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Katja Witschas
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
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17
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Iqbal S, Brünger T, Pérez-Palma E, Macnee M, Brunklaus A, Daly MJ, Campbell AJ, Hoksza D, May P, Lal D. Delineation of functionally essential protein regions for 242 neurodevelopmental genes. Brain 2023; 146:519-533. [PMID: 36256779 PMCID: PMC9924913 DOI: 10.1093/brain/awac381] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/12/2022] [Accepted: 09/04/2022] [Indexed: 01/25/2023] Open
Abstract
Neurodevelopmental disorders (NDDs), including severe paediatric epilepsy, autism and intellectual disabilities are heterogeneous conditions in which clinical genetic testing can often identify a pathogenic variant. For many of them, genetic therapies will be tested in this or the coming years in clinical trials. In contrast to first-generation symptomatic treatments, the new disease-modifying precision medicines require a genetic test-informed diagnosis before a patient can be enrolled in a clinical trial. However, even in 2022, most identified genetic variants in NDD genes are 'variants of uncertain significance'. To safely enrol patients in precision medicine clinical trials, it is important to increase our knowledge about which regions in NDD-associated proteins can 'tolerate' missense variants and which ones are 'essential' and will cause a NDD when mutated. In addition, knowledge about functionally indispensable regions in the 3D structure context of proteins can also provide insights into the molecular mechanisms of disease variants. We developed a novel consensus approach that overlays evolutionary, and population based genomic scores to identify 3D essential sites (Essential3D) on protein structures. After extensive benchmarking of AlphaFold predicted and experimentally solved protein structures, we generated the currently largest expert curated protein structure set for 242 NDDs and identified 14 377 Essential3D sites across 189 gene disorders associated proteins. We demonstrate that the consensus annotation of Essential3D sites improves prioritization of disease mutations over single annotations. The identified Essential3D sites were enriched for functional features such as intermembrane regions or active sites and discovered key inter-molecule interactions in protein complexes that were otherwise not annotated. Using the currently largest autism, developmental disorders, and epilepsies exome sequencing studies including >360 000 NDD patients and population controls, we found that missense variants at Essential3D sites are 8-fold enriched in patients. In summary, we developed a comprehensive protein structure set for 242 NDDs and identified 14 377 Essential3D sites in these. All data are available at https://es-ndd.broadinstitute.org for interactive visual inspection to enhance variant interpretation and development of mechanistic hypotheses for 242 NDDs genes. The provided resources will enhance clinical variant interpretation and in silico drug target development for NDD-associated genes and encoded proteins.
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Affiliation(s)
- Sumaiya Iqbal
- The Center for the Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Tobias Brünger
- Cologne Center for Genomics, University of Cologne, 50923 Köln, Germany
| | - Eduardo Pérez-Palma
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, 7610658 Las Condes, Santiago de Chile, Chile
| | - Marie Macnee
- Cologne Center for Genomics, University of Cologne, 50923 Köln, Germany
| | - Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow G12 8QQ, UK
- School of Health and Wellbeing, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Mark J Daly
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Institute for Molecular Medicine Finland (FIMM), Centre of Excellence in Complex Disease Genetics, University of Helsinki, 00100 Helsinki, Finland
| | - Arthur J Campbell
- The Center for the Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - David Hoksza
- Department of Software Engineering, Faculty of Mathematics and Physics, Charles University, 110 00 Staré Město, Czechia, Czech Republic
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg
| | - Dennis Lal
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics, University of Cologne, 50923 Köln, Germany
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA
- Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH 44106, USA
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18
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Chevalier P, Moreau A, Bessière F, Richard S, Chahine M, Millat G, Morel E, Paganelli F, Lesavre N, Placide L, Montestruc F, Ankou B, Puertas RD, Asatryan B, Delinière A. Identification of Cx43 variants predisposing to ventricular fibrillation in the acute phase of ST-elevation myocardial infarction. Europace 2023; 25:101-111. [PMID: 35942675 PMCID: PMC10103570 DOI: 10.1093/europace/euac128] [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: 02/09/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
AIMS Ventricular fibrillation (VF) occurring in the acute phase of ST-elevation myocardial infarction (STEMI) is the leading cause of sudden cardiac death worldwide. Several studies showed that reduced connexin 43 (Cx43) expression and reduced conduction velocity increase the risk of VF in acute myocardial infarction (MI). Furthermore, genetic background might predispose individuals to primary VF (PVF). The primary objective was to evaluate the presence of GJA1 variants in STEMI patients. The secondary objective was to evaluate the arrhythmogenic impact of GJA1 variants in STEMI patients with VF. METHODS AND RESULTS The MAP-IDM prospective cohort study included 966 STEMI patients and was designed to identify genetic predisposition to VF. A total of 483 (50.0%) STEMI patients with PVF were included. The presence of GJA1 variants increased the risk of VF in STEMI patients [from 49.1 to 70.8%, P = 0.0423; odds ratio (OR): 0.40; 95% confidence interval: 0.16-0.97; P = 0.04]. The risk of PVF decreased with beta-blocker intake (from 53.5 to 44.8%, P = 0.0085), atrial fibrillation (from 50.7 to 26.4%, P = 0.0022), and with left ventricular ejection fraction >50% (from 60.2 to 41.4%, P < 0.0001). Among 16 GJA1 variants, three novel heterozygous missense variants were identified in three patients: V236I, H248R, and I327M. In vitro studies of these variants showed altered Cx43 localization and decreased cellular communication, mainly during acidosis. CONCLUSION Connexin 43 variants are associated with increased VF susceptibility in STEMI patients. Restoring Cx43 function may be a potential therapeutic target to prevent PVF in patients with acute MI. CLINICAL TRIAL REGISTRATION Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00859300.
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Affiliation(s)
- Philippe Chevalier
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Adrien Moreau
- PhyMedExp, INSERM U1046, CNRS UMR9214, Université de Montpellier, CHU Arnaud de Villeneuve, 34295 Montpellier, France
| | - Francis Bessière
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Sylvain Richard
- PhyMedExp, INSERM U1046, CNRS UMR9214, Université de Montpellier, CHU Arnaud de Villeneuve, 34295 Montpellier, France
| | | | - Gilles Millat
- Laboratoire de Cardiogénétique moléculaire, Centre de biologie et pathologie Est, Bron, France
| | - Elodie Morel
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | | | | | - Leslie Placide
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | | | - Bénédicte Ankou
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Rosa Doñate Puertas
- Signaling and Cardiovascular Pathophysiology-UMR-S 1180, Inserm, Université Paris-Saclay, Paris, France
| | - Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Antoine Delinière
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
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19
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Increased Hemichannel Activity Displayed by a Connexin43 Mutation Causing a Familial Connexinopathy Exhibiting Hypotrichosis with Follicular Keratosis and Hyperostosis. Int J Mol Sci 2023; 24:ijms24032222. [PMID: 36768546 PMCID: PMC9916973 DOI: 10.3390/ijms24032222] [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: 12/19/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Mutations in the GJA1 gene that encodes connexin43 (Cx43) cause several rare genetic disorders, including diseases affecting the epidermis. Here, we examined the in vitro functional consequences of a Cx43 mutation, Cx43-G38E, linked to a novel human phenotype of hypotrichosis, follicular keratosis and hyperostosis. We found that Cx43-G38E was efficiently translated in Xenopus oocytes and localized to gap junction plaques in transfected HeLa cells. Cx43-G38E formed functional gap junction channels with the same efficiency as wild-type Cx43 in Xenopus oocytes, although voltage gating of the gap junction channels was altered. Notably, Cx43-G38E significantly increased membrane current flow through the formation of active hemichannels when compared to wild-type Cx43. These data demonstrate the association of increased hemichannel activity to a connexin mutation linked to a skeletal-cutaneous phenotype, suggesting that augmented hemichannel activity could play a role in skin and skeletal disorders caused by human Cx43 mutations.
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20
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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Machado RA, Júnior HM, Ferreira SBP, Leão LL, Coletta RD, Aguiar MJB. Novel mutations in GJA1 in two Brazilian families with oculodentodigital dysplasia. Oral Surg Oral Med Oral Pathol Oral Radiol 2023; 135:96-100. [PMID: 36396593 DOI: 10.1016/j.oooo.2022.09.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/10/2022] [Accepted: 09/22/2022] [Indexed: 01/02/2023]
Abstract
Oculodentodigital dysplasia (ODDD; MIM #164200), a rare genetic disorder characterized by abnormal craniofacial, dental, ocular, and digital features, is caused by mutations in GJA1 (gap junction alpha-1) gene and inherited in an autosomal dominant pattern. However, an autosomal recessive pattern is also reported. Here we described 2 families with members affected by ODDD. In the first family, the c.752G>C (p.S251T) and c.848C>T (p.P283L) heterozygous missense mutations and the c.825C>T (p.T275T) silent mutation were identified in the proband, which showed mild ODDD phenotypes, and in his mother, which displayed hemolytic anemia and thrombocytopenia. In the second family, the patients displayed typical features of ODDD, and Sanger sequencing identified a novel homozygous c.604C>T (p.R202C) missense mutation, whereas the parents carried the mutation. Together, these findings suggest that homozygous mutation in GJA1 induces a more severe ODDD phenotype, though interfamilial phenotype variability was observed, whereas compound heterozygous mutations in GJA1 cause a mild phenotype.
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Affiliation(s)
- Renato Assis Machado
- Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo (HRAC/USP), Bauru, São Paulo, Brazil; Department of Oral Diagnosis, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Hercílio Martelli Júnior
- Oral Diagnosis, Dental School, State University of Montes Claros, Unimontes, Montes Claros, Minas Gerais, Brazil; Center for Rehabilitation of Craniofacial Anomalies, Dental School, University of Alfenas, Minas Gerais, Brazil
| | | | - Letícia Lima Leão
- Special Medical Genetics Service, Clinical Hospital, Federal University of Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo D Coletta
- Department of Oral Diagnosis, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil; Graduate Program in Oral Biology, School of Dentistry, University of Campinas, Piracicaba, São Paulo, Brazil
| | - Marcos José Burle Aguiar
- Special Medical Genetics Service, Clinical Hospital, Federal University of Minas Gerais, UFMG, Belo Horizonte, Minas Gerais, Brazil
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22
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Fleck AP, Flotte AB, Si EP, Mu D. Loss of Gap Junction Factor Connexin 43 Results in an Increase of Exosomal Tetraspanins in Human Lung Cancer Cell Line A549. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000683. [PMID: 36447528 PMCID: PMC9701318 DOI: 10.17912/micropub.biology.000683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/06/2022] [Accepted: 11/13/2022] [Indexed: 01/25/2023]
Abstract
Gap junctions (GJs) and small extracellular vesicles such as exosomes are two fundamental intercellular communication (IC) mechanisms. We tested the hypothesis that the two IC mechanisms are connected by gene editing to inactivate a ubiquitously expression GJ factor (i.e., Cx43) in the human lung cancer cell line A549. Surprisingly, we observed that loss of Cx43 led to a buildup of exosomal tetraspanin proteins such as CD63 and CD9. Given the known activities of tetraspanins in cell-cell adhesion and vesicle uptake, our observation establishes an impetus to investigate further how these two IC mechanisms are intertwined.
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Affiliation(s)
| | | | | | - David Mu
- Eastern Virginia Medical School
,
Correspondence to: David Mu (
)
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23
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GSK3beta inhibitor-induced dental mesenchymal stem cells regulate ameloblast differentiation. J Oral Biosci 2022; 64:400-409. [DOI: 10.1016/j.job.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/11/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022]
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24
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Towards a Better Understanding of Genotype-Phenotype Correlations and Therapeutic Targets for Cardiocutaneous Genes: The Importance of Functional Studies above Prediction. Int J Mol Sci 2022; 23:ijms231810765. [PMID: 36142674 PMCID: PMC9503274 DOI: 10.3390/ijms231810765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Genetic variants in gene-encoding proteins involved in cell−cell connecting structures, such as desmosomes and gap junctions, may cause a skin and/or cardiac phenotype, of which the combination is called cardiocutaneous syndrome. The cardiac phenotype is characterized by cardiomyopathy and/or arrhythmias, while the skin particularly displays phenotypes such as keratoderma, hair abnormalities and skin fragility. The reported variants associated with cardiocutaneous syndrome, in genes DSP, JUP, DSC2, KLHL24, GJA1, are classified by interpretation guidelines from the American College of Medical Genetics and Genomics. The genotype−phenotype correlation, however, remains poorly understood. By providing an overview of variants that are assessed for a functional protein pathology, we show that this number (n = 115) is low compared to the number of variants that are assessed by in silico algorithms (>5000). As expected, there is a mismatch between the prediction of variant pathogenicity and the prediction of the functional effect compared to the real functional evidence. Aiding to improve genotype−phenotype correlations, we separate variants into ‘protein reducing’ or ‘altered protein’ variants and provide general conclusions about the skin and heart phenotype involved. We conclude by stipulating that adequate prognoses can only be given, and targeted therapies can only be designed, upon full knowledge of the protein pathology through functional investigation.
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25
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Jang DG, Kwon KY, Kweon YC, Kim BG, Myung K, Lee HS, Young Park C, Kwon T, Park TJ. GJA1 depletion causes ciliary defects by affecting Rab11 trafficking to the ciliary base. eLife 2022; 11:81016. [PMID: 36004726 PMCID: PMC9448326 DOI: 10.7554/elife.81016] [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: 06/13/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
The gap junction complex functions as a transport channel across the membrane. Among gap junction subunits, gap junction protein α1 (GJA1) is the most commonly expressed subunit. A recent study showed that GJA1 is necessary for the maintenance of motile cilia; however, the molecular mechanism and function of GJA1 in ciliogenesis remain unknown. Here, we examined the functions of GJA1 during ciliogenesis in human retinal pigment epithelium-1 and Xenopus laevis embryonic multiciliated-cells. GJA1 localizes to the motile ciliary axonemes or pericentriolar regions beneath the primary cilium. GJA1 depletion caused malformation of both the primary cilium and motile cilia. Further study revealed that GJA1 depletion affected several ciliary proteins such as BBS4, CP110, and Rab11 in the pericentriolar region and basal body. Interestingly, CP110 removal from the mother centriole was significantly reduced by GJA1 depletion. Importantly, Rab11, a key regulator during ciliogenesis, was immunoprecipitated with GJA1, and GJA1 knockdown caused the mislocalization of Rab11. These findings suggest that GJA1 regulates ciliogenesis by interacting with the Rab11-Rab8 ciliary trafficking pathway.
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Affiliation(s)
- Dong Gil Jang
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Keun Yeong Kwon
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Yeong Cheon Kweon
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Byung-Gyu Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
| | - Hyun-Shik Lee
- School of Life Sciences, Kyungpook National University, Daegu, Republic of Korea
| | - Chan Young Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Taejoon Kwon
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Tae Joo Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
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26
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Nowacki JC, Fields AM, Fu MM. Emerging cellular themes in leukodystrophies. Front Cell Dev Biol 2022; 10:902261. [PMID: 36003149 PMCID: PMC9393611 DOI: 10.3389/fcell.2022.902261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Abstract
Leukodystrophies are a broad spectrum of neurological disorders that are characterized primarily by deficiencies in myelin formation. Clinical manifestations of leukodystrophies usually appear during childhood and common symptoms include lack of motor coordination, difficulty with or loss of ambulation, issues with vision and/or hearing, cognitive decline, regression in speech skills, and even seizures. Many cases of leukodystrophy can be attributed to genetic mutations, but they have diverse inheritance patterns (e.g., autosomal recessive, autosomal dominant, or X-linked) and some arise from de novo mutations. In this review, we provide an updated overview of 35 types of leukodystrophies and focus on cellular mechanisms that may underlie these disorders. We find common themes in specialized functions in oligodendrocytes, which are specialized producers of membranes and myelin lipids. These mechanisms include myelin protein defects, lipid processing and peroxisome dysfunction, transcriptional and translational dysregulation, disruptions in cytoskeletal organization, and cell junction defects. In addition, non-cell-autonomous factors in astrocytes and microglia, such as autoimmune reactivity, and intercellular communication, may also play a role in leukodystrophy onset. We hope that highlighting these themes in cellular dysfunction in leukodystrophies may yield conceptual insights on future therapeutic approaches.
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27
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The molecular genetics of human appendicular skeleton. Mol Genet Genomics 2022; 297:1195-1214. [PMID: 35907958 DOI: 10.1007/s00438-022-01930-1] [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: 07/07/2021] [Accepted: 07/09/2022] [Indexed: 10/16/2022]
Abstract
Disorders that result from de-arrangement of growth, development and/or differentiation of the appendages (limbs and digit) are collectively called as inherited abnormalities of human appendicular skeleton. The bones of appendicular skeleton have central role in locomotion and movement. The different types of appendicular skeletal abnormalities are well described in the report of "Nosology and Classification of Genetic skeletal disorders: 2019 Revision". In the current article, we intend to present the embryology, developmental pathways, disorders and the molecular genetics of the appendicular skeletal malformations. We mainly focused on the polydactyly, syndactyly, brachydactyly, split-hand-foot malformation and clubfoot disorders. To our knowledge, only nine genes of polydactyly, five genes of split-hand-foot malformation, nine genes for syndactyly, eight genes for brachydactyly and only single gene for clubfoot have been identified to be involved in disease pathophysiology. The current molecular genetic data will help life sciences researchers working on the rare skeletal disorders. Moreover, the aim of present systematic review is to gather the published knowledge on molecular genetics of appendicular skeleton, which would help in genetic counseling and molecular diagnosis.
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28
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Bonetti G, Paolacci S, Samaja M, Maltese PE, Michelini S, Michelini S, Michelini S, Ricci M, Cestari M, Dautaj A, Medori MC, Bertelli M. Low Efficacy of Genetic Tests for the Diagnosis of Primary Lymphedema Prompts Novel Insights into the Underlying Molecular Pathways. Int J Mol Sci 2022; 23:ijms23137414. [PMID: 35806420 PMCID: PMC9267137 DOI: 10.3390/ijms23137414] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/16/2022] [Accepted: 06/29/2022] [Indexed: 02/07/2023] Open
Abstract
Lymphedema is a chronic inflammatory disorder caused by ineffective fluid uptake by the lymphatic system, with effects mainly on the lower limbs. Lymphedema is either primary, when caused by genetic mutations, or secondary, when it follows injury, infection, or surgery. In this study, we aim to assess to what extent the current genetic tests detect genetic variants of lymphedema, and to identify the major molecular pathways that underlie this rather unknown disease. We recruited 147 individuals with a clinical diagnosis of primary lymphedema and used established genetic tests on their blood or saliva specimens. Only 11 of these were positive, while other probands were either negative (63) or inconclusive (73). The low efficacy of such tests calls for greater insight into the underlying mechanisms to increase accuracy. For this purpose, we built a molecular pathways diagram based on a literature analysis (OMIM, Kegg, PubMed, Scopus) of candidate and diagnostic genes. The PI3K/AKT and the RAS/MAPK pathways emerged as primary candidates responsible for lymphedema diagnosis, while the Rho/ROCK pathway appeared less critical. The results of this study suggest the most important pathways involved in the pathogenesis of lymphedema, and outline the most promising diagnostic and candidate genes to diagnose this disease.
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Affiliation(s)
- Gabriele Bonetti
- MAGI’s LAB, 38068 Rovereto, Italy; (S.P.); (P.E.M.); (A.D.); (M.C.M.); (M.B.)
- Correspondence: ; Tel.: +39-0365-62-061
| | - Stefano Paolacci
- MAGI’s LAB, 38068 Rovereto, Italy; (S.P.); (P.E.M.); (A.D.); (M.C.M.); (M.B.)
| | | | | | - Sandro Michelini
- Vascular Diagnostics and Rehabilitation Service, Marino Hospital, ASL Roma 6, 00047 Marino, Italy;
| | - Serena Michelini
- Unit of Physical Medicine, “Sapienza” University of Rome, 00185 Rome, Italy;
| | | | - Maurizio Ricci
- Division of Rehabilitation Medicine, Azienda Ospedaliero-Universitaria, Ospedali Riuniti di Ancona, 60126 Ancona, Italy;
| | - Marina Cestari
- Study Centre Pianeta Linfedema, 05100 Terni, Italy;
- Lymphology Sector of the Rehabilitation Service, USLUmbria2, 05100 Terni, Italy
| | - Astrit Dautaj
- MAGI’s LAB, 38068 Rovereto, Italy; (S.P.); (P.E.M.); (A.D.); (M.C.M.); (M.B.)
| | - Maria Chiara Medori
- MAGI’s LAB, 38068 Rovereto, Italy; (S.P.); (P.E.M.); (A.D.); (M.C.M.); (M.B.)
| | - Matteo Bertelli
- MAGI’s LAB, 38068 Rovereto, Italy; (S.P.); (P.E.M.); (A.D.); (M.C.M.); (M.B.)
- MAGI Group, 25010 San Felice del Benaco, Italy;
- MAGI Euregio, 39100 Bolzano, Italy
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29
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Lukowicz-Bedford RM, Farnsworth DR, Miller AC. Connexinplexity: the spatial and temporal expression of connexin genes during vertebrate organogenesis. G3 (BETHESDA, MD.) 2022; 12:jkac062. [PMID: 35325106 PMCID: PMC9073686 DOI: 10.1093/g3journal/jkac062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/24/2022] [Indexed: 11/28/2022]
Abstract
Animal development requires coordinated communication between cells. The Connexin family of proteins is a major contributor to intercellular communication in vertebrates by forming gap junction channels that facilitate the movement of ions, small molecules, and metabolites between cells. Additionally, individual hemichannels can provide a conduit to the extracellular space for paracrine and autocrine signaling. Connexin-mediated communication is widely used in epithelial, neural, and vascular development and homeostasis, and most tissues likely use this form of communication. In fact, Connexin disruptions are of major clinical significance contributing to disorders developing from all major germ layers. Despite the fact that Connexins serve as an essential mode of cellular communication, the temporal and cell-type-specific expression patterns of connexin genes remain unknown in vertebrates. A major challenge is the large and complex connexin gene family. To overcome this barrier, we determined the expression of all connexins in zebrafish using single-cell RNA-sequencing of entire animals across several stages of organogenesis. Our analysis of expression patterns has revealed that few connexins are broadly expressed, but rather, most are expressed in tissue- or cell-type-specific patterns. Additionally, most tissues possess a unique combinatorial signature of connexin expression with dynamic temporal changes across the organism, tissue, and cell. Our analysis has identified new patterns for well-known connexins and assigned spatial and temporal expression to genes with no-existing information. We provide a field guide relating zebrafish and human connexin genes as a critical step toward understanding how Connexins contribute to cellular communication and development throughout vertebrate organogenesis.
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Affiliation(s)
| | - Dylan R Farnsworth
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR 97403, USA
| | - Adam C Miller
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, OR 97403, USA
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30
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Zaib T, Rashid H, Khan H, Zhou X, Sun P. Recent Advances in Syndactyly: Basis, Current Status and Future Perspectives. Genes (Basel) 2022; 13:771. [PMID: 35627156 PMCID: PMC9141913 DOI: 10.3390/genes13050771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 02/05/2023] Open
Abstract
A comprehensive summary of recent knowledge in syndactyly (SD) is important for understanding the genetic etiology of SD and disease management. Thus, this review article provides background information on SD, as well as insights into phenotypic and genetic heterogeneity, newly identified gene mutations in various SD types, the role of HOXD13 in limb deformities, and recently introduced modern surgical techniques for SD. This article also proposes a procedure for genetic analysis to obtain a clearer genotype-phenotype correlation for SD in the future. We briefly describe the classification of non-syndromic SD based on variable phenotypes to explain different phenotypic features and mutations in the various genes responsible for the pathogenesis of different types of SD. We describe how different types of mutation in HOXD13 cause various types of SD, and how a mutation in HOXD13 could affect its interaction with other genes, which may be one of the reasons behind the differential phenotypes and incomplete penetrance. Furthermore, we also discuss some recently introduced modern surgical techniques, such as free skin grafting, improved flap techniques, and dermal fat grafting in combination with the Z-method incision, which have been successfully practiced clinically with no post-operative complications.
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Affiliation(s)
- Tahir Zaib
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
| | - Hibba Rashid
- Department of Biotechnology and Microbiology, Abasyn University, Peshawar 25000, Pakistan
| | - Hanif Khan
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
| | - Xiaoling Zhou
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
| | - Pingnan Sun
- Stem Cell Research Center, Shantou University Medical College, Shantou 515041, China
- (T.Z.)
- (X.Z.)
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China
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31
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Guo YH, Yang YQ. Atrial Fibrillation: Focus on Myocardial Connexins and Gap Junctions. BIOLOGY 2022; 11:489. [PMID: 35453689 PMCID: PMC9029470 DOI: 10.3390/biology11040489] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Atrial fibrillation (AF) represents the most common type of clinical cardiac arrhythmia worldwide and contributes to substantial morbidity, mortality and socioeconomic burden. Aggregating evidence highlights the strong genetic basis of AF. In addition to chromosomal abnormalities, pathogenic mutations in over 50 genes have been causally linked to AF, of which the majority encode ion channels, cardiac structural proteins, transcription factors and gap junction channels. In the heart, gap junctions comprised of connexins (Cxs) form intercellular pathways responsible for electrical coupling and rapid coordinated action potential propagation between adjacent cardiomyocytes. Among the 21 isoforms of connexins already identified in the mammal genomes, 5 isoforms (Cx37, Cx40, Cx43, Cx45 and Cx46) are expressed in human heart. Abnormal electrical coupling between cardiomyocytes caused by structural remodeling of gap junction channels (alterations in connexin distribution and protein levels) has been associated with enhanced susceptibility to AF and recent studies have revealed multiple causative mutations or polymorphisms in 4 isoforms of connexins predisposing to AF. In this review, an overview of the genetics of AF is made, with a focus on the roles of mutant myocardial connexins and gap junctions in the pathogenesis of AF, to underscore the hypothesis that cardiac connexins are a major molecular target in the management of AF.
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Affiliation(s)
- Yu-Han Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
- Cardiovascular Research Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
- Center Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
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32
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Kawatsura R, Hara Y, Akiyama M, Tachikawa N, Nakahama KI. Gap junctional intercellular communication attenuates osteoclastogenesis induced by activated osteoblasts. Biochem Biophys Res Commun 2022; 597:71-76. [PMID: 35124462 DOI: 10.1016/j.bbrc.2022.01.118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/29/2022] [Indexed: 11/02/2022]
Abstract
Osteoblasts participate in both bone formation through the synthesis of extracellular matrix and osteoclast differentiation through the expression of osteoclast differentiation factor. Osteoblasts communicate with each other via gap junctions (GJ), which enable small molecules, such as cAMP, to move to adjacent cells. Therefore, we focused on the role of cAMP propagation between osteoblasts via GJ in the osteoclast-supporting activity of osteoblasts. Osteoclast-supporting activity was evaluated by a co-culture system of osteoblasts with bone marrow-derived mononuclear cells. In this system, ablation of Gja1, a gene encoding connexin 43, in osteoblasts promoted osteoclastogenesis induced by prostaglandin E2 (PGE2). A phosphodiesterase 4 inhibitor increased both osteoclastogenesis and the intracellular cAMP concentration ([cAMP]i) in osteoblasts. Individual cell analysis of [cAMP]i in osteoblasts revealed different responses of each osteoblast to PGE2. Moreover, measurement of real-time [cAMP]i demonstrated cAMP movement from cell to cell via GJ. The inhibition of GJ resulted in the upregulation of [cAMP]i in osteoblasts stimulated by PGE2. This study suggested that GJ intercellular communication exerts protective effects against excess osteoclastogenesis via cAMP movement between osteoblasts.
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Affiliation(s)
- Risa Kawatsura
- Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan; Regenerative and Reconstructive Oral Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Yusuke Hara
- Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Masako Akiyama
- Research Administration Division, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Noriko Tachikawa
- Regenerative and Reconstructive Oral Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan
| | - Ken-Ichi Nakahama
- Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
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33
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Cheng L, Cring MR, Wadkins DA, Kuehn MH. Absence of Connexin 43 results in smaller retinas and arrested, depolarized retinal progenitor cells in human retinal organoids. Stem Cells 2022; 40:592-604. [PMID: 35263762 DOI: 10.1093/stmcls/sxac017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/18/2022] [Indexed: 11/14/2022]
Abstract
The development of the vertebrate retina relies on complex regulatory mechanisms to achieve its characteristic layered morphology containing multiple neuronal cell types. While connexin 43 (CX43) is not expressed by mature retinal neurons mutations in its gene GJA1 are associated with microphthalmia and low vision in patients. To delineate how lack of CX43 affects retinal development, GJA1 was disrupted in human induced pluripotent stem cells (hiPSCs) (GJA1-/-) using CRISPR/Cas9 editing, and these were subsequently differentiated into retinal organoids. GJA1-/- hiPSCs do not display defects in self-renewal and pluripotency, but the resulting organoids are smaller with a thinner neural retina and decreased abundance of many retinal cell types. CX43-deficient organoids express lower levels of the neural marker PAX6 and the retinal progenitor cell (RPC) markers PAX6, SIX3, and SIX6. Conversely, expression of the early neuroectoderm markers SOX1 and SOX2 remains high in GJA1-/- organoids throughout their development. Lack of CX43 results in an increased population of CHX10-positive RPCs that are smaller, disorganized, do not become polarized, and possess a limited ability to commit to retinal fate specification. Our data indicate that lack of CX43 causes a developmental arrest in RPCs that subsequently leads to pan-retinal defects and stunted ocular growth.
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Affiliation(s)
- Lin Cheng
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, IA, USA.,Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Matthew R Cring
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - David A Wadkins
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, IA, USA.,Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, IA, USA.,Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, IA, USA.,Institute for Vision Research, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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34
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van der Sande E, Haarman AEG, Quint WH, Tadema KCD, Meester-Smoor MA, Kamermans M, De Zeeuw CI, Klaver CCW, Winkelman BHJ, Iglesias AI. The Role of GJD2(Cx36) in Refractive Error Development. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 35262731 PMCID: PMC8934558 DOI: 10.1167/iovs.63.3.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/16/2022] [Indexed: 02/06/2023] Open
Abstract
Refractive errors are common eye disorders characterized by a mismatch between the focal power of the eye and its axial length. An increased axial length is a common cause of the refractive error myopia (nearsightedness). The substantial increase in myopia prevalence over the last decades has raised public health concerns because myopia can lead to severe ocular complications later in life. Genomewide association studies (GWAS) have made considerable contributions to the understanding of the genetic architecture of refractive errors. Among the hundreds of genetic variants identified, common variants near the gap junction delta-2 (GJD2) gene have consistently been reported as one of the top hits. GJD2 encodes the connexin 36 (Cx36) protein, which forms gap junction channels and is highly expressed in the neural retina. In this review, we provide current evidence that links GJD2(Cx36) to the development of myopia. We summarize the gap junctional communication in the eye and the specific role of GJD2(Cx36) in retinal processing of visual signals. Finally, we discuss the pathways involving dopamine and gap junction phosphorylation and coupling as potential mechanisms that may explain the role of GJD2(Cx36) in refractive error development.
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Affiliation(s)
- Emilie van der Sande
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Amsterdam, The Netherlands
| | - Annechien E. G. Haarman
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Wim H. Quint
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kirke C. D. Tadema
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Magda A. Meester-Smoor
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Maarten Kamermans
- Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Amsterdam, The Netherlands
- Department of Biomedical Physics and Biomedical Photonics, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Chris I. De Zeeuw
- Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Caroline C. W. Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Beerend H. J. Winkelman
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Institute for Neuroscience (NIN), Royal Dutch Academy of Art & Science (KNAW), Amsterdam, The Netherlands
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Adriana I. Iglesias
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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De Kinderen P, Meester J, Loeys B, Peeters S, Gouze E, Woods S, Mortier G, Verstraeten A. Differentiation of Induced Pluripotent Stem Cells Into Chondrocytes: Methods and Applications for Disease Modeling and Drug Discovery. J Bone Miner Res 2022; 37:397-410. [PMID: 35124831 DOI: 10.1002/jbmr.4524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 01/25/2022] [Accepted: 02/01/2022] [Indexed: 11/11/2022]
Abstract
Induced pluripotent stem cell (iPSC) technology allows pathomechanistic and therapeutic investigation of human heritable disorders affecting tissue types whose collection from patients is difficult or even impossible. Among them are cartilage diseases. Over the past decade, iPSC-chondrocyte disease models have been shown to exhibit several key aspects of known disease mechanisms. Concurrently, an increasing number of protocols to differentiate iPSCs into chondrocytes have been published, each with its respective (dis)advantages. In this review we provide a comprehensive overview of the different differentiation approaches, the hitherto described iPSC-chondrocyte disease models and mechanistic and/or therapeutic insights that have been derived from their investigation, and the current model limitations. Key lessons are that the most appropriate differentiation approach is dependent upon the cartilage disease under investigation and that further optimization is still required to recapitulate the in vivo cartilage. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Pauline De Kinderen
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Josephina Meester
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Bart Loeys
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium.,Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Silke Peeters
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Elvire Gouze
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
| | - Steven Woods
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Geert Mortier
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Aline Verstraeten
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
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36
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Sanchez AC, Thren ED, Iovine MK, Skibbens RV. Esco2 and cohesin regulate CRL4 ubiquitin ligase ddb1 expression and thalidomide teratogenicity. Cell Cycle 2022; 21:501-513. [PMID: 34989322 PMCID: PMC8942496 DOI: 10.1080/15384101.2021.2023304] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 11/03/2022] Open
Abstract
Cornelia de Lange syndrome (CdLS) and Roberts syndrome (RBS) are severe developmental maladies that arise from mutation of cohesin (including SMC3, CdLS) and ESCO2 (RBS). Though ESCO2 activates cohesin, CdLS and RBS etiologies are currently considered non-synonymous and for which pharmacological treatments are unavailable. Here, we identify a unifying mechanism that integrates these genetic maladies to pharmacologically-induced teratogenicity via thalidomide. Our results reveal that Esco2 and cohesin co-regulate the transcription of a component of CRL4 ubiquitin ligase through which thalidomide exerts teratogenic effects. These findings are the first to link RBS and CdLS to thalidomide teratogenicity and offer new insights into treatments.
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Affiliation(s)
- Annie C. Sanchez
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Elise D. Thren
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - M. Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Robert V. Skibbens
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
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Michell-Robinson MA, Perrier S, Lucia C, Tran LT, Thiffault I, Köhler W, Bernard G. Oculo-dento-digital Dysplasia: A Cause of Hypomyelinating Leukodystrophy in Adults. Neurology 2022; 98:675-677. [PMID: 35190466 PMCID: PMC9052568 DOI: 10.1212/wnl.0000000000200228] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Mackenzie A Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Cassandra Lucia
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Luan T Tran
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada.,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
| | - Isabelle Thiffault
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, MO, USA.,Faculty of Medicine, University of Missouri Kansas City, Kansas City, MO, USA.,Department of Pathology, Children's Mercy Hospital, Kansas City, MO, USA
| | - Wolfgang Köhler
- Department of Neurology, Leukodystrophy Center, University of Leipzig Medical Center, Leipzig, Germany
| | - Genevieve Bernard
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada. .,Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada.,Department of Pediatrics, McGill University, Montréal, QC, Canada.,Department of Human Genetics, McGill University, Montréal, QC, Canada.,Department of Specialized Medicine, Division of Medical Genetics, Montreal Children's Hospital and McGill University Health Centre, Montréal, QC, Canada
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Gap Junction-Dependent and -Independent Functions of Connexin43 in Biology. BIOLOGY 2022; 11:biology11020283. [PMID: 35205149 PMCID: PMC8869330 DOI: 10.3390/biology11020283] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 12/21/2022]
Abstract
For the first time in animal evolution, the emergence of gap junctions allowed direct exchanges of cellular substances for communication between two cells. Innexin proteins constituted primordial gap junctions until the connexin protein emerged in deuterostomes and took over the gap junction function. After hundreds of millions of years of gene duplication, the connexin gene family now comprises 21 members in the human genome. Notably, GJA1, which encodes the Connexin43 protein, is one of the most widely expressed and commonly studied connexin genes. The loss of Gja1 in mice leads to swelling and a blockage of the right ventricular outflow tract and death of the embryos at birth, suggesting a vital role of Connexin43 gap junction in heart development. Since then, the importance of Connexin43-mediated gap junction function has been constantly expanded to other types of cells. Other than forming gap junctions, Connexin43 can also form hemichannels to release or uptake small molecules from the environment or even mediate many physiological processes in a gap junction-independent manner on plasma membranes. Surprisingly, Connexin43 also localizes to mitochondria in the cell, playing important roles in mitochondrial potassium import and respiration. At the molecular level, Connexin43 mRNA and protein are processed with very distinct mechanisms to yield carboxyl-terminal fragments with different sizes, which have their unique subcellular localization and distinct biological activities. Due to many exciting advancements in Connexin43 research, this review aims to start with a brief introduction of Connexin43 and then focuses on updating our knowledge of its gap junction-independent functions.
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Interrogation of Carboxy-Terminus Localized GJA1 Variants Associated with Erythrokeratodermia Variabilis et Progressiva. Int J Mol Sci 2022; 23:ijms23010486. [PMID: 35008913 PMCID: PMC8745721 DOI: 10.3390/ijms23010486] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/17/2021] [Accepted: 12/24/2021] [Indexed: 02/04/2023] Open
Abstract
Although inherited GJA1 (encoding Cx43) gene mutations most often lead to oculodentodigital dysplasia and related disorders, four variants have been linked to erythrokeratodermia variabilis et progressiva (EKVP), a skin disorder characterized by erythematous and hyperkeratotic lesions. While two autosomal-dominant EKVP-linked GJA1 mutations have been shown to lead to augmented hemichannels, the consequence(s) of keratinocytes harboring a de novo P283L variant alone or in combination with a de novo T290N variant remain unknown. Interestingly, these variants reside within or adjacent to a carboxy terminus polypeptide motif that has been shown to be important in regulating the internalization and degradation of Cx43. Cx43-rich rat epidermal keratinocytes (REKs) or Cx43-ablated REKs engineered to express fluorescent protein-tagged P283L and/or T290N variants formed prototypical gap junctions at cell-cell interfaces similar to wildtype Cx43. Dye coupling and dye uptake studies further revealed that each variant or a combination of both variants formed functional gap junction channels, with no evidence of augmented hemichannel function or induction of cell death. Tracking the fate of EKVP-associated variants in the presence of the protein secretion blocker brefeldin A, or an inhibitor of protein synthesis cycloheximide, revealed that P283L or the combination of P283L and T290N variants either significantly extended Cx43 residency on the cell surface of keratinocytes or delayed its degradation. However, caution is needed in concluding that this modest change in the Cx43 life cycle is sufficient to cause EKVP, or whether an additional underlying mechanism or another unidentified gene mutation is contributing to the pathogenesis found in patients. This question will be resolved if further patients are identified where whole exome sequencing reveals a Cx43 P283L variant alone or, in combination with a T290N variant, co-segregates with EKVP across several family generations.
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Pang J, Thomas N, Tsuchiya D, Parmely T, Yan D, Xie T, Wang Y. Step-by-step preparation of mouse eye sections for routine histology, immunofluorescence, and RNA in situ hybridization multiplexing. STAR Protoc 2021; 2:100879. [PMID: 34806041 PMCID: PMC8585658 DOI: 10.1016/j.xpro.2021.100879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
It can be challenging to maintain tissue integrity using established histology protocols. Here, we describe a protocol composed of Hartman's fixation, window technique, microwave-based tissue processing, optimized depigmentation, and antigen retrieval pretreatment. This is followed by the ViewRNA single-molecule fluorescence in situ hybridization and immunofluorescence techniques to optimize routine histological staining and molecular histology multiplexing assays. Our protocol is highly reproducible in any laboratory and may decrease animal usage and lab resource expenditure. For complete details on the use and execution of this protocol, please refer to Pang et al. (2021).
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Affiliation(s)
- Ji Pang
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
- School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Nancy Thomas
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Dai Tsuchiya
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Tari Parmely
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Deyue Yan
- School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Ting Xie
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA
| | - Yongfu Wang
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
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41
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Hultström M, Peng D, Becirovic Agic M, Cupples CG, Cupples WA, Mitrou N. Surgical trauma is associated with renal immune cell activation in rats: A microarray study. Physiol Rep 2021; 9:e15142. [PMID: 34889077 PMCID: PMC8661512 DOI: 10.14814/phy2.15142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 12/20/2022] Open
Abstract
Acute kidney injury (AKI) is a common perioperative complication that is associated with increased mortality. This study investigates the renal gene expression in male Long-Evans rats after prolonged anesthesia and surgery to detect molecular mechanisms that could predispose the kidneys to injury upon further insults. Healthy and streptozotocin diabetic rats that underwent autoregulatory investigation in an earlier study were compared to rats that were sacrificed quickly for mRNA quantification in the same study. Prolonged surgery caused massive changes in renal mRNA expression by microarray analysis, which was validated by quantitative real-time PCR with good correlation. Furthermore, bioinformatics analysis using gene ontology and pathway analysis identified biological processes involved in immune system activation, such as immune system processes (p = 1.3 × 10-80 ), immune response (p = 1.3 × 10-60 ), and regulation of cytokine production (p = 1.7 × 10-52 ). PCR analysis of specific cell type markers indicated that the gene activation in kidneys was most probably macrophages, while granulocytes and T cell appeared less activated. Immunohistochemistry was used to quantify immune cell infiltration and showed no difference between groups indicating that the genetic activation depends on the activation of resident cells, or infiltration of a relatively small number of highly activated cells. In follow-up experiments, surgery was performed on healthy rats under standard and sterile condition showing similar expression of immune cell markers, which suggests that the inflammation was indeed caused by the surgical trauma rather than by bacterial infection. In conclusion, surgical trauma is associated with rapid activation of immune cells, most likely macrophages in rat kidneys.
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Affiliation(s)
- Michael Hultström
- Department of Medical Cell BiologyIntegrative PhysiologyUppsala UniversityUppsalaSweden
- Department of Surgical SciencesAnesthesia and Intensive Care MedicineUppsala UniversityUppsalaSweden
| | - Di Peng
- Department of Medical Cell BiologyIntegrative PhysiologyUppsala UniversityUppsalaSweden
| | - Mediha Becirovic Agic
- Department of Medical Cell BiologyIntegrative PhysiologyUppsala UniversityUppsalaSweden
| | - Claire G. Cupples
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - William A. Cupples
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityBurnabyBritish ColumbiaCanada
| | - Nicholas Mitrou
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityBurnabyBritish ColumbiaCanada
- Department of SurgeryUniversity of Western OntarioLondonOntarioCanada
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Ping X, Liang J, Shi K, Bao J, Wu J, Yu X, Tang X, Zou J, Shentu X. Rapamycin relieves the cataract caused by ablation of Gja8b through stimulating autophagy in zebrafish. Autophagy 2021; 17:3323-3337. [PMID: 33472493 PMCID: PMC8632074 DOI: 10.1080/15548627.2021.1872188] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 12/29/2020] [Indexed: 12/30/2022] Open
Abstract
Macroautophagy/autophagy is known to be important for intracellular quality control in the lens. GJA8 is a major gap junction protein in vertebrate lenses. Mutations in GJA8 cause cataracts in humans. The well-known cataractogenesis mechanism is that mutated GJA8 leads to abnormal assembly of gap junctions, resulting in defects in intercellular communication among lens cells. In this study, we observed that ablation of Gja8b (a homolog of mammalian GJA8) in zebrafish led to severe defects in organelle degradation, an important cause of cataractogenesis in developing lens. The role of autophagy in organelle degradation in lens remains disputable. Intriguingly, we also observed that ablation of Gja8b induced deficient autophagy in the lens. More importantly, in vivo treatment of zebrafish with rapamycin, an autophagy activator that inhibits MAPK/JNK and MTORC1 signaling, stimulated autophagy in the lens and relieved the defects in organelle degradation, resulting in the mitigation of cataracts in gja8b mutant zebrafish. Conversely, inhibition of autophagy by treatment with the chemical reagent 3-MA blocked these recovery effects, suggesting the important roles of autophagy in organelle degradation in the lens in gja8b mutant zebrafish. Further studies in HLE cells revealed that GJA8 interacted with ATG proteins. Overexpression of GJA8 stimulated autophagy in HLE cells. These data suggest an unrecognized cataractogenesis mechanism caused by ablation of Gja8b and a potential treatment for cataracts by stimulating autophagy in the lens.Abbreviations: 3-MA: 3-methyladenine; ATG: autophagy related; AV: autophagic vacuoles; Dpf: days post fertilization; GJA1: gap junction protein alpha 1; GJA3: gap junction protein alpha 3; GJA8: gap junction protein alpha 8; Hpf: hours post fertilization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; WT: wild type.
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Affiliation(s)
- Xiyuan Ping
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jiancheng Liang
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
- The Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Kexin Shi
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jing Bao
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jing Wu
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Xiaoning Yu
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Xiajing Tang
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
| | - Jian Zou
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
- The Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Xingchao Shentu
- Eye Center of the Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
- Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China
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43
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Hayashi R, Shimomura Y. Update of recent findings in genetic hair disorders. J Dermatol 2021; 49:55-67. [PMID: 34676598 DOI: 10.1111/1346-8138.16204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 10/03/2021] [Accepted: 10/04/2021] [Indexed: 11/30/2022]
Abstract
Genetic hair disorders, although unusual, are not very rare, and dermatologists often have opportunities to see patients. Significant advances in molecular genetics have led to identifying many causative genes for genetic hair disorders, including the recently identified causative genes, such as LSS and C3ORF52. Many patients have been detected with autosomal recessive woolly hair/hypotrichosis in the Japanese population caused by founder mutations in the LIPH gene. Additionally, many patients with genetic hair disorders caused by other genes have been reported in East Asia including Japan. Understanding genetic hair disorders is essential for dermatologists, and the findings obtained from analyzing these diseases will contribute to revealing the mechanisms of hair follicle morphogenesis and development in humans.
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Affiliation(s)
- Ryota Hayashi
- Division of Dermatology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yutaka Shimomura
- Department of Dermatology, Yamaguchi University Graduate School of Medicine, Ube, Japan
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44
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Yamada A, Yoshizaki K, Ishikawa M, Saito K, Chiba Y, Fukumoto E, Hino R, Hoshikawa S, Chiba M, Nakamura T, Iwamoto T, Fukumoto S. Connexin 43-Mediated Gap Junction Communication Regulates Ameloblast Differentiation via ERK1/2 Phosphorylation. Front Physiol 2021; 12:748574. [PMID: 34630166 PMCID: PMC8500398 DOI: 10.3389/fphys.2021.748574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/25/2021] [Indexed: 11/24/2022] Open
Abstract
Connexin 43 (Cx43) is an integral membrane protein that forms gap junction channels. These channels mediate intercellular transport and intracellular signaling to regulate organogenesis. The human disease oculodentodigital dysplasia (ODDD) is caused by mutations in Cx43 and is characterized by skeletal, ocular, and dental abnormalities including amelogenesis imperfecta. To clarify the role of Cx43 in amelogenesis, we examined the expression and function of Cx43 in tooth development. Single-cell RNA-seq analysis and immunostaining showed that Cx43 is highly expressed in pre-secretory ameloblasts, differentiated ameloblasts, and odontoblasts. Further, we investigated the pathogenic mechanisms of ODDD by analyzing Cx43-null mice. These mice developed abnormal teeth with multiple dental epithelium layers. The expression of enamel matrix proteins such as ameloblastin (Ambn), which is critical for enamel formation, was significantly reduced in Cx43-null mice. TGF-β1 induces Ambn transcription in dental epithelial cells. The induction of Ambn expression by TGF-β1 depends on the density of the cultured cells. Cell culture at low densities reduces cell–cell contact and reduces the effect of TGF-β1 on Ambn induction. When cell density was high, Ambn expression by TGF-β1 was enhanced. This induction was inhibited by the gap junction inhibitors, oleamide, and 18α-grycyrrhizic acid and was also inhibited in cells expressing Cx43 mutations (R76S and R202H). TGF-β1-mediated phosphorylation and nuclear translocation of ERK1/2, but not Smad2/3, were suppressed by gap junction inhibitors. Cx43 gap junction activity is required for TGF-β1-mediated Runx2 phosphorylation through ERK1/2, which forms complexes with Smad2/3. In addition to its gap junction activity, Cx43 may also function as a Ca2+ channel that regulates slow Ca2+ influx and ERK1/2 phosphorylation. TGF-β1 transiently increases intracellular calcium levels, and the increase in intracellular calcium over a short period was not related to the expression level of Cx43. However, long-term intracellular calcium elevation was enhanced in cells overexpressing Cx43. Our results suggest that Cx43 regulates intercellular communication through gap junction activity by modulating TGF-β1-mediated ERK signaling and enamel formation.
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Affiliation(s)
- Aya Yamada
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Keigo Yoshizaki
- Section of Orthodontics and Dentofacial Orthopedics, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Masaki Ishikawa
- The Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| | - Kan Saito
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Yuta Chiba
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Emiko Fukumoto
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Ryoko Hino
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Seira Hoshikawa
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Mitsuki Chiba
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Takashi Nakamura
- Division of Molecular Pharmacology and Cell Biophysics, Department of Oral Biology, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Tsutomu Iwamoto
- Division of Oral Health Science, Department of Pediatric Dentistry/Special Needs Dentistry, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Satoshi Fukumoto
- Division of Pediatric Dentistry, Department of Oral Health and Development Sciences, Tohoku University Graduate School of Dentistry, Sendai, Japan.,Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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45
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Quan Y, Du Y, Wu C, Gu S, Jiang JX. Connexin hemichannels regulate redox potential via metabolite exchange and protect lens against cellular oxidative damage. Redox Biol 2021; 46:102102. [PMID: 34474393 PMCID: PMC8408634 DOI: 10.1016/j.redox.2021.102102] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 11/23/2022] Open
Abstract
Increased oxidative stress contributes to cataract formation during aging. Anterior epithelial cells are a frontline antioxidant defense system with powerful capacities to maintain redox homeostasis and lens transparency. In this study, we report a new molecular mechanism of connexin (Cx) hemichannels (HCs) in lens epithelial cells to protect lens against oxidative stress. Our results showed haploinsufficiency of Cx43 elevated oxidative stress and susceptibility to cataracts in the mouse lens. Cx43 HCs opened in response to hydrogen peroxide (H2O2) or ultraviolet radiation (UVR) in human lens epithelium HLE-B3 cells, and this activation contributed to a cellular protective mechanism against oxidative stress-induced apoptotic cell death. Furthermore, we found that Cx43 HCs mediated the exchange of oxidants and antioxidants in lens epithelial cells undergoing oxidative stress. These transporting activities facilitated a reduction of intracellular reactive oxygen species (ROS) accumulation and maintained the intracellular glutathione (GSH) level through the exchange of redox metabolites and change of anti-oxidative gene expression. In addition, we show that Cx43 HCs can be regulated by the intracellular redox state and this regulation is mediated by residue Cys260 located at the Cx43 C-terminus. Together, our results demonstrate that Cx43 HCs activated by oxidative stress in the lens epithelial cells play a key role in maintaining redox homeostasis in lens under oxidative stress. Our findings contribute to advancing our understanding of oxidative stress induced lens disorders, such as age-related non-congenital cataracts.
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Affiliation(s)
- Yumeng Quan
- Department of Ophthalmology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China; Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Yu Du
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Changrui Wu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Sumin Gu
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Jean X Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA.
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46
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Quan Y, Du Y, Tong Y, Gu S, Jiang JX. Connexin Gap Junctions and Hemichannels in Modulating Lens Redox Homeostasis and Oxidative Stress in Cataractogenesis. Antioxidants (Basel) 2021; 10:1374. [PMID: 34573006 PMCID: PMC8464761 DOI: 10.3390/antiox10091374] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
The lens is continuously exposed to oxidative stress insults, such as ultraviolet radiation and other oxidative factors, during the aging process. The lens possesses powerful oxidative stress defense systems to maintain its redox homeostasis, one of which employs connexin channels. Connexins are a family of proteins that form: (1) Hemichannels that mediate the communication between the intracellular and extracellular environments, and (2) gap junction channels that mediate cell-cell communication between adjacent cells. The avascular lens transports nutrition and metabolites through an extensive network of connexin channels, which allows the passage of small molecules, including antioxidants and oxidized wastes. Oxidative stress-induced post-translational modifications of connexins, in turn, regulates gap junction and hemichannel permeability. Recent evidence suggests that dysfunction of connexins gap junction channels and hemichannels may induce cataract formation through impaired redox homeostasis. Here, we review the recent advances in the knowledge of connexin channels in lens redox homeostasis and their response to cataract-related oxidative stress by discussing two major aspects: (1) The role of lens connexins and channels in oxidative stress and cataractogenesis, and (2) the impact and underlying mechanism of oxidative stress in regulating connexin channels.
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Affiliation(s)
| | | | | | | | - Jean X. Jiang
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA; (Y.Q.); (Y.D.); (Y.T.); (S.G.)
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47
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Gap Junction Channelopathies and Calmodulinopathies. Do Disease-Causing Calmodulin Mutants Affect Direct Cell-Cell Communication? Int J Mol Sci 2021; 22:ijms22179169. [PMID: 34502077 PMCID: PMC8431743 DOI: 10.3390/ijms22179169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/19/2021] [Accepted: 08/21/2021] [Indexed: 11/24/2022] Open
Abstract
The cloning of connexins cDNA opened the way to the field of gap junction channelopathies. Thus far, at least 35 genetic diseases, resulting from mutations of 11 different connexin genes, are known to cause numerous structural and functional defects in the central and peripheral nervous system as well as in the heart, skin, eyes, teeth, ears, bone, hair, nails and lymphatic system. While all of these diseases are due to connexin mutations, minimal attention has been paid to the potential diseases of cell–cell communication caused by mutations of Cx-associated molecules. An important Cx accessory protein is calmodulin (CaM), which is the major regulator of gap junction channel gating and a molecule relevant to gap junction formation. Recently, diseases caused by CaM mutations (calmodulinopathies) have been identified, but thus far calmodulinopathy studies have not considered the potential effect of CaM mutations on gap junction function. The major goal of this review is to raise awareness on the likely role of CaM mutations in defects of gap junction mediated cell communication. Our studies have demonstrated that certain CaM mutants affect gap junction channel gating or expression, so it would not be surprising to learn that CaM mutations known to cause diseases also affect cell communication mediated by gap junction channels.
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48
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Patel R, Singh SK, Bhattacharya V, Ali A. Novel HOXD13 variants in syndactyly type 1b and type 1c, and a new spectrum of TP63-related disorders. J Hum Genet 2021; 67:43-49. [PMID: 34321610 DOI: 10.1038/s10038-021-00963-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 07/09/2021] [Indexed: 12/15/2022]
Abstract
Syndactyly is the most common limb defect depicting the bony and/or cutaneous fusion of digits. Syndactyly can be of various types depending on the digits involved in the fusion. To date, eight syndactyly-associated genes have been reported, of which HOXD13 and GJA1 have been explored in a few syndactyly but most of them have unknown underlying genetics. In the present study HOXD13, GJA1 and TP63 genes have been screened by resequencing in 24 unrelated sporadic cases with various syndactyly. The screening revealed two pathogenic HOXD13 variants, NM_000523:c.500 A > G [p.(Y167C)], and NM_000523:c.961 A > C [p.(T321P)] in syndactyly type 1b and type 1c, respectively. This is the first report to identify HOXD13 pathogenic variant in syndactyly type 1b and third report in syndactyly type 1c pathogenesis. Furthermore, this study also reports a TP63 pathogenic variant, NM_003722:c.953 G > A [p.(R318H)] in Ectrodactyly and Cleft lip and palate (ECLP). In conclusion, the current study expands the clinical spectrum of HOXD13 and TP63-related disorders.
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Affiliation(s)
- Rashmi Patel
- Centre for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi, India.,National Cancer Institute, Frederick, NIH, USA
| | | | - Visweswar Bhattacharya
- Department of Plastic Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Akhtar Ali
- Centre for Genetic Disorders, Institute of Science, Banaras Hindu University, Varanasi, India.
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49
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Bai D, Wang J, Li T, Chan R, Atalla M, Chen RC, Khazaneh MT, An RJ, Stathopulos PB. Differential Domain Distribution of gnomAD- and Disease-Linked Connexin Missense Variants. Int J Mol Sci 2021; 22:ijms22157832. [PMID: 34360596 PMCID: PMC8346055 DOI: 10.3390/ijms22157832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 11/26/2022] Open
Abstract
Twenty-one human genes encode connexins, a family of homologous proteins making gap junction (GJ) channels, which mediate direct intercellular communication to synchronize tissue/organ activities. Genetic variants in more than half of the connexin genes are associated with dozens of different Mendelian inherited diseases. With rapid advances in DNA sequencing technology, more variants are being identified not only in families and individuals with diseases but also in people in the general population without any apparent linkage to Mendelian inherited diseases. Nevertheless, it remains challenging to classify the pathogenicity of a newly identified connexin variant. Here, we analyzed the disease- and Genome Aggregation Database (gnomAD, as a proxy of the general population)-linked variants in the coding region of the four disease-linked α connexin genes. We found that the most abundant and position-sensitive missense variants showed distinct domain distribution preference between disease- and gnomAD-linked variants. Plotting missense variants on topological and structural models revealed that disease-linked missense variants are highly enriched on the structurally stable/resolved domains, especially the pore-lining domains, while the gnomAD-linked missense variants are highly enriched in the structurally unstable/unresolved domains, especially the carboxyl terminus. In addition, disease-linked variants tend to be on highly conserved residues and those positions show evolutionary co-variation, while the gnomAD-linked missense variants are likely on less conserved residue positions and on positions without co-variation. Collectively, the revealed distribution patterns of disease- and gnomAD-linked missense variants further our understanding of the GJ structure–biological function relationship, which is valuable for classifying the pathogenicity of newly identified connexin variants.
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50
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Jewlal E, Barr K, Laird DW, Willmore KE. Connexin 43 contributes to phenotypic robustness of the mouse skull. Dev Dyn 2021; 250:1810-1827. [PMID: 34091987 DOI: 10.1002/dvdy.381] [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: 03/26/2021] [Revised: 05/13/2021] [Accepted: 06/02/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND We compared skull shape and variation among genetically modified mice that exhibit different levels of connexin43 (Cx43) channel function, to determine whether Cx43 contributes to craniofacial phenotypic robustness. Specifically, we used two heterozygous mutant mouse models (G60S/+ and I130T/+) that, when compared to their wildtype counterparts, have an ~80% and ~50% reduction in Cx43 function, respectively. RESULTS Both mutant strains showed significant differences in skull shape compared to wildtype littermates and while these differences were more severe in the G60S/+ mouse, shape differences were localized to similar regions of the skull in both mutants. However, increased skull shape variation was observed in G60S/+ mutants only. Additionally, covariation of skull structures was disrupted in the G60S/+ mutants only, indicating that while a 50% reduction in Cx43 function is sufficient to cause a shift in mean skull shape, the threshold for Cx43 function for disrupting craniofacial phenotypic robustness is lower. CONCLUSIONS Collectively, our results indicate Cx43 can contribute to phenotypic robustness of the skull through a nonlinear relationship between Cx43 gap junctional function and phenotypic outcomes.
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Affiliation(s)
- Elizabeth Jewlal
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Katherine E Willmore
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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