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Recognition of Melanocytes in Immuno-Neuroendocrinology and Circadian Rhythms: Beyond the Conventional Melanin Synthesis. Cells 2022; 11:cells11132082. [PMID: 35805166 PMCID: PMC9266247 DOI: 10.3390/cells11132082] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 12/15/2022] Open
Abstract
Melanocytes produce melanin to protect the skin from UV-B radiation. Notwithstanding, the spectrum of their functions extends far beyond their well-known role as melanin production factories. Melanocytes have been considered as sensory and computational cells. The neurotransmitters, neuropeptides, and other hormones produced by melanocytes make them part of the skin’s well-orchestrated and complex neuroendocrine network, counteracting environmental stressors. Melanocytes can also actively mediate the epidermal immune response. Melanocytes are equipped with ectopic sensory systems similar to the eye and nose and can sense light and odor. The ubiquitous inner circadian rhythm controls the body’s basic physiological processes. Light not only affects skin photoaging, but also regulates inner circadian rhythms and communicates with the local neuroendocrine system. Do melanocytes “see” light and play a unique role in photoentrainment of the local circadian clock system? Why, then, are melanocytes responsible for so many mysterious functions? Do these complex functional devices work to maintain homeostasis locally and throughout the body? In addition, melanocytes have also been shown to be localized in internal sites such as the inner ear, brain, and heart, locations not stimulated by sunlight. Thus, what can the observation of extracutaneous melanocytes tell us about the “secret identity” of melanocytes? While the answers to some of these intriguing questions remain to be discovered, here we summarize and weave a thread around available data to explore the established and potential roles of melanocytes in the biological communication of skin and systemic homeostasis, and elaborate on important open issues and propose ways forward.
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Vona B, Schwartzbaum DA, Rodriguez AA, Lewis SS, Toosi MB, Radhakrishnan P, Bozan N, Akın R, Doosti M, Manju R, Duman D, Sineni CJ, Nampoothiri S, Karimiani EG, Houlden H, Bademci G, Tekin M, Girisha KM, Maroofian R, Douzgou S. Biallelic KITLG variants lead to a distinct spectrum of hypomelanosis and sensorineural hearing loss. J Eur Acad Dermatol Venereol 2022; 36:1606-1611. [PMID: 35543077 PMCID: PMC9546089 DOI: 10.1111/jdv.18207] [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: 12/11/2021] [Accepted: 04/21/2022] [Indexed: 11/30/2022]
Abstract
Background Pathogenic variants in KITLG, a crucial protein involved in pigmentation and neural crest cell migration, cause non‐syndromic hearing loss, Waardenburg syndrome type 2, familial progressive hyperpigmentation and familial progressive hyper‐ and hypopigmentation, all of which are inherited in an autosomal dominant manner. Objectives To describe the genotypic and clinical spectrum of biallelic KITLG‐variants. Methods We used a genotype‐first approach through the GeneMatcher data sharing platform to collect individuals with biallelic KITLG variants and reviewed the literature for overlapping reports. Results We describe the first case series with biallelic KITLG variants; we expand the known hypomelanosis spectrum to include a ‘sock‐and‐glove‐like’, symmetric distribution, progressive repigmentation and generalized hypomelanosis. We speculate that KITLG biallelic loss‐of‐function variants cause generalized hypomelanosis, whilst variants with residual function lead to a variable auditory‐pigmentary disorder mostly reminiscent of Waardenburg syndrome type 2 or piebaldism. Conclusions We provide consolidating evidence that biallelic KITLG variants cause a distinct auditory‐pigmentary disorder. We evidence a significant clinical variability, similar to the one previously observed in KIT‐related piebaldism.
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Affiliation(s)
- B Vona
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany.,Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - D A Schwartzbaum
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - A A Rodriguez
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - S S Lewis
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - M B Toosi
- Department of Pediatrics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - P Radhakrishnan
- Suma Genomics Private Limited and Manipal Center for Biotherapeutics Research, Manipal Academy of Higher Education, Manipal, India
| | - N Bozan
- Department of Otolaryngology, Yuzuncu Yıl University Faculty of Medicine, Van, Turkey
| | - R Akın
- Department of Otolaryngology, Yuzuncu Yıl University Faculty of Medicine, Van, Turkey
| | - M Doosti
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran
| | - R Manju
- Renai Medicity, Cochin, Kerala, India
| | - D Duman
- Department of Audiology, Ankara University Faculty of Health Sciences, Ankara, Turkey
| | - C J Sineni
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - S Nampoothiri
- Department of Paediatric Genetics, Amrita Institute of Medical Sciences and Research Centre, Kochi, India
| | - E G Karimiani
- Department of Medical Genetics, Next Generation Genetic Polyclinic, Mashhad, Iran.,Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace, London, SW17 0RE, UK.,Innovative medical research center, Mashhad branch, Islamic Azad University, Mashhad, Iran
| | - H Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - G Bademci
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - M Tekin
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA.,Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - K M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.,Suma Genomics Private Limited and Manipal Center for Biotherapeutics Research, Manipal Academy of Higher Education, Manipal, India
| | - R Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London, UK
| | - S Douzgou
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway.,Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PL, UK
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Al-janabi AM, Ahmmed HS, Al-Khafaji SM. Connexin 26 (GJB2) gene mutations linked with autosomal recessive non-syndromic sensor neural hearing loss in the Iraqi population. J Med Life 2021; 14:841-846. [PMID: 35126756 PMCID: PMC8811675 DOI: 10.25122/jml-2021-0152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/08/2021] [Indexed: 11/19/2022] Open
Abstract
Deafness is a total or partial hearing loss that may appear at any age and with different degrees of severity. Approximately 50% of hearing loss have a genetic origin, and among them, non-syndromic sensorineural deafness represents about 70% of the cases. From them, 80% correspond to autosomal recessive inheritance deafness. Autosomal recessive deafness was not studied enough at the molecular level in Iraq. This study aimed to verify the frequency of three GJB2 mutations in non-syndromic sensorineural deafness in the Iraqi population. The current case-control study was conducted from January 2018 to January 2020. The study included 95 deafness patients (55 males and 40 females) and 110 healthy control group. Age and sex were matched between the two groups. In order to detect c.35delG, 235delC, and 167delT mutations in the GJB2 gene, we employed the PCR-RFLP technique. The c.35delG was the main frequent mutation encountered with the GJB2 gene among patients with autosomal recessive non-syndromic sensorineural hearing loss. Among them, 35 (36.8%) were homozygous, 40 (42.1%) were heterozygous, and 20 (21.1%) were wild genotypes. The second-degree mutation in the GJB2 gene was c.235delC mutation, which from the 95 deaf patients, there were 20 (21.1%) with homozygous, 33 (34.7%) heterozygous, and 42 (44.2%) wild genotypes. None of the 95 deaf patients showed the c.167delT mutation, and no mutations appeared in the control group. Our data concluded that the GJB2 c.35delG and c.235delC gene mutations were the main cause of autosomal recessive non-syndromic sensorineural hearing loss in the Iraqi deaf population.
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