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Forini F, Nicolini G, Amato R, Balzan S, Saba A, Bertolini A, Andreucci E, Marracci S, Melecchi A, Terlizzi D, Zucchi R, Iervasi G, Lulli M, Casini G. Local modulation of thyroid hormone signaling in the retina affects the development of diabetic retinopathy. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166892. [PMID: 37758065 DOI: 10.1016/j.bbadis.2023.166892] [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: 07/25/2023] [Revised: 09/05/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023]
Abstract
Thyroid hormone (TH) dyshomeostasis is associated with poor prognosis in acute and prolonged illness, but its role in diabetic retinopathy (DR) has never been investigated. Here, we characterized the TH system in the retinas of db/db mice and highlighted regulatory processes in MIO-M1 cells. In the db/db retinas, typical functional traits and molecular signatures of DR were paralleled by a tissue-restricted reduction of TH levels. A local condition of low T3 (LT3S) was also demonstrated, which was likely to be induced by deiodinase 3 (DIO3) upregulation, and by decreased expression of DIO2 and of TH receptors. Concurrently, T3-responsive genes, including mitochondrial markers and microRNAs (miR-133-3p, 338-3p and 29c-3p), were downregulated. In MIO-M1 cells, a feedback regulatory circuit was evidenced whereby miR-133-3p triggered the post-transcriptional repression of DIO3 in a T3-dependent manner, while high glucose (HG) led to DIO3 upregulation through a nuclear factor erythroid 2-related factor 2-hypoxia-inducible factor-1 pathway. Finally, an in vitro simulated condition of early LT3S and hyperglycemia correlated with reduced markers of both mitochondrial function and stress response, which was reverted by T3 replacement. Together, the data suggest that, in the early phases of DR, a DIO3-driven LT3S may be protective against retinal stress, while, in the chronic phase, it not only fails to limit HG-induced damage, but also increases cell vulnerability likely due to persistent mitochondrial dysfunction.
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Affiliation(s)
- Francesca Forini
- Institute of Clinical Physiology, National Research Council, Pisa, Italy.
| | | | - Rosario Amato
- Department of Biology, University of Pisa, Pisa, Italy.
| | - Silvana Balzan
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Alessandro Saba
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy; Center for Instrument Sharing (CISUP), University of Pisa, Pisa, Italy.
| | - Andrea Bertolini
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.
| | - Elena Andreucci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy.
| | | | | | - Domiziana Terlizzi
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Riccardo Zucchi
- Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.
| | - Giorgio Iervasi
- Department of Biomedical Sciences, National Research Council, Rome, Italy.
| | - Matteo Lulli
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy.
| | - Giovanni Casini
- Department of Biology, University of Pisa, Pisa, Italy; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy; Center for Instrument Sharing (CISUP), University of Pisa, Pisa, Italy.
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Sawant OB, Jidigam VK, Wilcots K, Fuller RD, Samuels I, Rao S. Thyroid Activating Enzyme, Deiodinase II Is Required for Photoreceptor Function in the Mouse Model of Retinopathy of Prematurity. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 33237298 PMCID: PMC7691789 DOI: 10.1167/iovs.61.13.36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 10/30/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose Retinopathy of prematurity (ROP) is a severe complication of premature infants, leading to vision loss when untreated. Presently, the molecular mechanisms underlying ROP are still far from being clearly understood. This study sought to investigate whether thyroid hormone (TH) signaling contributes to the neuropathology of ROP using the mouse model of ROP to evaluate longitudinal photoreceptor function. Methods Animals were exposed to hyperoxia from P7 to P12 to induce retinopathy, thereafter the animals were returned to room air (normoxia). The thyroid-activating enzyme type 2 deiodinases (Dio2) knockout (KO) mice and the littermate controls that were exposed to hyperoxia or maintained in room air and were then analyzed. The retinal function was evaluated using electroretinograms (ERGs) at three and seven weeks followed by histologic assessments with neuronal markers to detect cellular changes in the retina. Rhodopsin protein levels were measured to validate the results obtained from the immunofluorescence analyses. Results In the ROP group, the photoreceptor ERG responses are considerably lower both in the control and the Dio2 KO animals at P23 compared to the non-ROP group. In agreement with the ERG responses, loss of Dio2 results in mislocalized cone nuclei, and abnormal rod bipolar cell dendrites extending into the outer nuclear layer. The retinal function is compromised in the adult Dio2 KO animals, although the cellular changes are less severe. Despite the reduction in scotopic a-wave amplitudes, rhodopsin levels are similar in the adult mice, across all genotypes irrespective of exposure to hyperoxia. Conclusions Using the mouse model of ROP, we show that loss of Dio2 exacerbates the effects of hyperoxia-induced retinal deficits that persist in the adults. Our data suggest that aberrant Dio2/TH signaling is an important factor in the pathophysiology of the visual dysfunction observed in the oxygen-induced retinopathy model of ROP.
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Affiliation(s)
- Onkar B. Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Eversight, Cleveland, Ohio, United States
| | - Vijay K. Jidigam
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Kenya Wilcots
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Department of Chemistry, Cleveland State University, Cleveland, Ohio, United States
| | - Rebecca D. Fuller
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Ivy Samuels
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, United States
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States
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Groeneweg S, van Geest FS, Peeters RP, Heuer H, Visser WE. Thyroid Hormone Transporters. Endocr Rev 2020; 41:5637505. [PMID: 31754699 DOI: 10.1210/endrev/bnz008] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Thyroid hormone transporters at the plasma membrane govern intracellular bioavailability of thyroid hormone. Monocarboxylate transporter (MCT) 8 and MCT10, organic anion transporting polypeptide (OATP) 1C1, and SLC17A4 are currently known as transporters displaying the highest specificity toward thyroid hormones. Structure-function studies using homology modeling and mutational screens have led to better understanding of the molecular basis of thyroid hormone transport. Mutations in MCT8 and in OATP1C1 have been associated with clinical disorders. Different animal models have provided insight into the functional role of thyroid hormone transporters, in particular MCT8. Different treatment strategies for MCT8 deficiency have been explored, of which thyroid hormone analogue therapy is currently applied in patients. Future studies may reveal the identity of as-yet-undiscovered thyroid hormone transporters. Complementary studies employing animal and human models will provide further insight into the role of transporters in health and disease. (Endocrine Reviews 41: 1 - 55, 2020).
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Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ferdy S van Geest
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
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Vancamp P, Bourgeois NMA, Houbrechts AM, Darras VM. Knockdown of the thyroid hormone transporter MCT8 in chicken retinal precursor cells hampers early retinal development and results in a shift towards more UV/blue cones at the expense of green/red cones. Exp Eye Res 2018; 178:135-147. [PMID: 30273578 DOI: 10.1016/j.exer.2018.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 09/21/2018] [Accepted: 09/27/2018] [Indexed: 12/19/2022]
Abstract
Thyroid hormones (THs) play a crucial role in coordinating brain development in vertebrates. They fine-tune processes like cell proliferation, migration, and differentiation mainly by regulating the transcriptional activity of many essential genes. Regulators of TH availability thereby define the cellular concentration of the bioactive 3,5,3'-triiodothyronine, which binds to nuclear TH receptors. One important regulator, the monocarboxylate transporter 8 (MCT8), facilitates cellular TH uptake and is known to be necessary for correct brain development, but data on its potential role during retinal development is lacking. The retinal cyto-architecture has been conserved throughout vertebrate evolution, and we used the chicken embryo to study the need for MCT8 during retinal development. Its external development allows easy manipulation, and MCT8 is abundantly expressed in the retina from early stages onwards. We induced MCT8 knockdown by electroporating a pRFP-MCT8-RNAi vector into the retinal precursor cells (RPCs) at embryonic day 4 (E4), and studied the consequences for early (E6) and late (E18) retinal development. The empty pRFP-RNAi vector was used as a control. RPC proliferation was reduced at E6. This resulted in cellular hypoplasia and a thinner retina at E18 where mainly photoreceptors and horizontal cells were lost, the two predominant cell types that are born around the stage of electroporation. At E6, differentiation into retinal ganglion cells and amacrine cells was delayed. However, since the proportion of a given cell type within the transfected cell population at E18 was similar in knockdown and controls, the partial loss of some cell types was most-likely due to reduced RPC proliferation and not impaired cell differentiation. Photoreceptors displayed delayed migration at first, but had successfully reached the outer nuclear layer at E18. However, they increasingly differentiated into short wavelength-sensitive cones at the expense of medium/long wavelength-sensitive cones, while the proportion of rods was unaltered. Improperly formed sublaminae in the inner plexiform layer additionally suggested defects in synaptogenesis. Altogether, our data echoes effects of hypothyroidism and the loss of some other regulators of TH availability in the developing zebrafish and rodent retina. Therefore, the expression of MCT8 in RPCs is crucial for adequate TH uptake during cell type-specific events in retinal development.
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Affiliation(s)
- Pieter Vancamp
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Nele M A Bourgeois
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Anne M Houbrechts
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium
| | - Veerle M Darras
- KU Leuven, Laboratory of Comparative Endocrinology, Department of Biology, B-3000, Leuven, Belgium.
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Retinal S-opsin dominance in Ansell's mole-rats (Fukomys anselli) is a consequence of naturally low serum thyroxine. Sci Rep 2018. [PMID: 29531249 PMCID: PMC5847620 DOI: 10.1038/s41598-018-22705-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Mammals usually possess a majority of medium-wavelength sensitive (M-) and a minority of short-wavelength sensitive (S-) opsins in the retina, enabling dichromatic vision. Unexpectedly, subterranean rodents from the genus Fukomys exhibit an S-opsin majority, which is exceptional among mammals, albeit with no apparent adaptive value. Because thyroid hormones (THs) are pivotal for M-opsin expression and metabolic rate regulation, we have, for the first time, manipulated TH levels in the Ansell's mole-rat (Fukomys anselli) using osmotic pumps. In Ansell's mole-rats, the TH thyroxine (T4) is naturally low, likely as an adaptation to the harsh subterranean ecological conditions by keeping resting metabolic rate (RMR) low. We measured gene expression levels in the eye, RMR, and body mass (BM) in TH-treated animals. T4 treatment increased both, S- and M-opsin expression, albeit M-opsin expression at a higher degree. However, this plasticity was only given in animals up to approximately 2.5 years. Mass-specific RMR was not affected following T4 treatment, although BM decreased. Furthermore, the T4 inactivation rate is naturally higher in F. anselli compared to laboratory rodents. This is the first experimental evidence that the S-opsin majority in Ansell's mole-rats is a side effect of low T4, which is downregulated to keep RMR low.
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Sawant OB, Horton AM, Zucaro OF, Chan R, Bonilha VL, Samuels IS, Rao S. The Circadian Clock Gene Bmal1 Controls Thyroid Hormone-Mediated Spectral Identity and Cone Photoreceptor Function. Cell Rep 2017; 21:692-706. [PMID: 29045837 PMCID: PMC5647869 DOI: 10.1016/j.celrep.2017.09.069] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/15/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022] Open
Abstract
Circadian clocks regulate various aspects of photoreceptor physiology, but their contribution to photoreceptor development and function is unclear. Cone photoreceptors are critical for color vision. Here, we define the molecular function of circadian activity within cone photoreceptors and reveal a role for the clock genes Bmal1 and Per2 in regulating cone spectral identity. ChIP analysis revealed that BMAL1 binds to the promoter region of the thyroid hormone (TH)-activating enzyme type 2 iodothyronine deiodinase (Dio2) and thus regulates the expression of Dio2. TH treatment resulted in a partial rescue of the phenotype caused by the loss of Bmal1, thus revealing a functional relationship between Bmal1 and Dio2 in establishing cone photoreceptor identity. Furthermore, Bmal1 and Dio2 are required to maintain cone photoreceptor functional integrity. Overall, our results suggest a mechanism by which circadian proteins can locally regulate the availability of TH and influence tissue development and function.
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Affiliation(s)
- Onkar B Sawant
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Amanda M Horton
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Olivia F Zucaro
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Ricky Chan
- Institute for Computational Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Vera L Bonilha
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - Ivy S Samuels
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Sujata Rao
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
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