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Zhao Y, Guo DF, Morgan DA, Cho YE, Rahmouni K. Adipocyte-specific disruption of the BBSome causes metabolic and autonomic dysfunction. Am J Physiol Regul Integr Comp Physiol 2024; 327:R54-R65. [PMID: 38738295 DOI: 10.1152/ajpregu.00039.2024] [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: 02/12/2024] [Revised: 04/16/2024] [Accepted: 05/03/2024] [Indexed: 05/14/2024]
Abstract
Obesity is a major public health issue due to its association with type 2 diabetes, hypertension, and other cardiovascular risks. The BBSome, a complex of eight conserved Bardet-Biedl syndrome (BBS) proteins, has emerged as a key regulator of energy and glucose homeostasis as well as cardiovascular function. However, the importance of adipocyte BBSome in controlling these physiological processes is not clear. Here, we show that adipocyte-specific constitutive disruption of the BBSome through selective deletion of the Bbs1 gene adiponectin (AdipoCre/Bbs1fl/fl mice) does not affect body weight under normal chow or high-fat and high-sucrose diet (HFHSD). However, constitutive BBSome deficiency caused impairment in glucose tolerance and insulin sensitivity. Similar phenotypes were observed after inducible adipocyte-specific disruption of the BBSome (AdipoCreERT2/Bbs1fl/fl mice). Interestingly, a significant increase in renal sympathetic nerve activity, measured using multifiber recording in the conscious state, was observed in AdipoCre/Bbs1fl/fl mice on both chow and HFHSD. A significant increase in tail-cuff arterial pressure was also observed in chow-fed AdipoCre/Bbs1fl/fl mice, but this was not reproduced when arterial pressure was measured by radiotelemetry. Moreover, AdipoCre/Bbs1fl/fl mice had no significant alterations in vascular reactivity. On the other hand, AdipoCre/Bbs1fl/fl mice displayed impaired baroreceptor reflex sensitivity when fed HFHSD, but not on normal chow. Taken together, these data highlight the relevance of the adipocyte BBSome for the regulation of glucose homeostasis and sympathetic traffic. The BBSome also contributes to baroreflex sensitivity under HFHSD, but not normal chow.NEW & NOTEWORTHY The current study show how genetic manipulation of fat cells impacts various functions of the body including sensitivity to the hormone insulin.
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Affiliation(s)
- Yuying Zhao
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Interdisciplinary Graduate Program in Human Toxicology, Iowa City, Iowa, United States
| | - Deng-Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Veterans Affairs Health Care System, Iowa City, Iowa, United States
| | - Donald A Morgan
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Veterans Affairs Health Care System, Iowa City, Iowa, United States
| | - Young-Eun Cho
- College of Nursing, University of Iowa, Iowa City, Iowa, United States
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Veterans Affairs Health Care System, Iowa City, Iowa, United States
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
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Rahmouni K. Neural Circuits Underlying Reciprocal Cardiometabolic Crosstalk: 2023 Arthur C. Corcoran Memorial Lecture. Hypertension 2024; 81:1233-1243. [PMID: 38533662 PMCID: PMC11096079 DOI: 10.1161/hypertensionaha.124.22066] [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] [Indexed: 03/28/2024]
Abstract
The interplay of various body systems, encompassing those that govern cardiovascular and metabolic functions, has evolved alongside the development of multicellular organisms. This evolutionary process is essential for the coordination and maintenance of homeostasis and overall health by facilitating the adaptation of the organism to internal and external cues. Disruption of these complex interactions contributes to the development and progression of pathologies that involve multiple organs. Obesity-associated cardiovascular risks, such as hypertension, highlight the significant influence that metabolic processes exert on the cardiovascular system. This cardiometabolic communication is reciprocal, as indicated by substantial evidence pointing to the ability of the cardiovascular system to affect metabolic processes, with pathophysiological implications in disease conditions. In this review, I outline the bidirectional nature of the cardiometabolic interaction, with special emphasis on the impact that metabolic organs have on the cardiovascular system. I also discuss the contribution of the neural circuits and autonomic nervous system in mediating the crosstalk between cardiovascular and metabolic functions in health and disease, along with the molecular mechanisms involved.
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Affiliation(s)
- Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Veterans Affairs Health Care System, Iowa City, Iowa
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Rouabhi Y, Guo DF, Zhao Y, Rahmouni K. Metabolic consequences of skeletal muscle- and liver-specific BBSome deficiency. Am J Physiol Endocrinol Metab 2023; 325:E711-E722. [PMID: 37909854 PMCID: PMC10864019 DOI: 10.1152/ajpendo.00174.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/04/2023] [Accepted: 10/19/2023] [Indexed: 11/03/2023]
Abstract
The BBSome is a protein complex composed of eight Bardet-Biedl syndrome (BBS) proteins including BBS1. Humans and mice lacking a functional BBSome display obesity and type 2 diabetes, highlighting the importance of this protein complex for metabolic regulation. However, the contribution of the BBSome in insulin-sensitive tissues such as skeletal muscle and liver to metabolic regulation is ill-defined. Here, we show that disruption of the BBSome through Bbs1 gene deletion in the skeletal muscle had no effect on body weight or glucose handling, but improved insulin sensitivity of female mice without changing insulin receptor signaling. Interestingly, when fed an obesogenic diet, male mice lacking the Bbs1 gene in skeletal muscle exhibited heightened insulin sensitivity despite the comparable weight gain and glucose tolerance relative to controls. On the other hand, normal chow-fed mice missing the Bbs1 gene in hepatocytes displayed increased body weight, as well as impaired glucose handling and insulin sensitivity. This was associated with attenuated insulin signaling in liver and hepatocytes, but not skeletal muscle and white adipose tissue. Moreover, hepatocytes lacking the Bbs1 gene displayed significant reduction in plasma membrane insulin receptor levels due to the mitochondrial dysfunction evoked by loss of the BBSome. Together, these findings demonstrate that myocyte BBSome is minimally involved in metabolic regulation, whereas the hepatic BBSome plays a critical role in the control of energy homeostasis and insulin sensitivity through its requirement for insulin receptor trafficking.NEW & NOTEWORTHY The ongoing epidemic of obesity and associated illnesses highlights the need to understand the biological processes that regulate energy balance. Here, we identified an important role for a protein complex called BBSome in the control of hepatic function. We show that the liver BBSome is necessary to maintain body weight and blood glucose levels due to its requirements to generate energy and detect insulin, a hormone that is essential for metabolic regulation.
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Affiliation(s)
- Younes Rouabhi
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
| | - Deng-Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Veterans Affairs Health Care System, Iowa City, Iowa, United States
| | - Yuying Zhao
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Veterans Affairs Health Care System, Iowa City, Iowa, United States
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
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Tian X, Zhao H, Zhou J. Organization, functions, and mechanisms of the BBSome in development, ciliopathies, and beyond. eLife 2023; 12:e87623. [PMID: 37466224 DOI: 10.7554/elife.87623] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 07/06/2023] [Indexed: 07/20/2023] Open
Abstract
The BBSome is an octameric protein complex that regulates ciliary transport and signaling. Mutations in BBSome subunits are closely associated with ciliary defects and lead to ciliopathies, notably Bardet-Biedl syndrome. Over the past few years, there has been significant progress in elucidating the molecular organization and functions of the BBSome complex. An improved understanding of BBSome-mediated biological events and molecular mechanisms is expected to help advance the development of diagnostic and therapeutic approaches for BBSome-related diseases. Here, we review the current literature on the structural assembly, transport regulation, and molecular functions of the BBSome, emphasizing its roles in cilium-related processes. We also provide perspectives on the pathological role of the BBSome in ciliopathies as well as how these can be exploited for therapeutic benefit.
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Affiliation(s)
- Xiaoyu Tian
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Huijie Zhao
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
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Hsu Y, Bhattarai S, Thompson JM, Mahoney A, Thomas J, Mayer SK, Datta P, Garrison J, Searby CC, Vandenberghe LH, Seo S, Sheffield VC, Drack AV. Subretinal gene therapy delays vision loss in a Bardet-Biedl Syndrome type 10 mouse model. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:164-181. [PMID: 36700052 PMCID: PMC9841241 DOI: 10.1016/j.omtn.2022.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022]
Abstract
Blindness in Bardet-Biedl syndrome (BBS) is caused by dysfunction and loss of photoreceptor cells in the retina. BBS10, mutations of which account for approximately 21% of all BBS cases, encodes a chaperonin protein indispensable for the assembly of the BBSome, a cargo adaptor important for ciliary trafficking. The loss of BBSome function in the eye causes a reduced light sensitivity of photoreceptor cells, photoreceptor ciliary malformation, dysfunctional ciliary trafficking, and photoreceptor cell death. Cone photoreceptors lacking BBS10 have congenitally low electrical function in electroretinography. In this study, we performed gene augmentation therapy by injecting a viral construct subretinally to deliver the coding sequence of the mouse Bbs10 gene to treat retinal degeneration in a BBS10 mouse model. Long-term efficacy was assessed by measuring the electrical functions of the retina over time, imaging of the treated regions to visualize cell survival, conducting visually guided swim assays to measure functional vision, and performing retinal histology. We show that subretinal gene therapy slowed photoreceptor cell death and preserved retinal function in treated eyes. Notably, cone photoreceptors regained their electrical function after gene augmentation. Measurement of functional vision showed that subretinal gene therapy provided a significant benefit in delaying vision loss.
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Affiliation(s)
- Ying Hsu
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Sajag Bhattarai
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Jacob M. Thompson
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Angela Mahoney
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Jacintha Thomas
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Sara K. Mayer
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, USA
| | - Poppy Datta
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Janelle Garrison
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | | | - Luk H. Vandenberghe
- Massachusetts Eye and Ear, Grousbeck Gene Therapy Center, Harvard Medical School, Boston, MA, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Val C. Sheffield
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
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Stump M, Guo DF, Rahmouni K. T cell-specific deficiency in BBSome component BBS1 interferes with selective immune responses. Am J Physiol Regul Integr Comp Physiol 2023; 324:R161-R170. [PMID: 36534590 PMCID: PMC9844976 DOI: 10.1152/ajpregu.00243.2022] [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: 09/28/2022] [Revised: 12/09/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022]
Abstract
Bsardet Biedl syndrome (BBS) is a genetic condition associated with various clinical features including cutaneous disorders and certain autoimmune and inflammatory diseases pointing to a potential role of BBS proteins in the regulation of immune function. BBS1 protein, which is a key component of the BBSome, a protein complex involved in the regulation of cilia function and other cellular processes, has been implicated in the immune synapse assembly by promoting the centrosome polarization to the antigen-presenting cells. Here, we assessed the effect of disrupting the BBSome, through Bbs1 gene deletion, in T cells. Interestingly, mice lacking the Bbs1 gene specifically in T cells (T-BBS1-/-) displayed normal body weight, adiposity, and glucose handling, but have smaller spleens. However, T-BBS1-/- mice had no change in the proportion and absolute number of B cells and T cells in the spleen and lymph nodes. There was also no alteration in the CD4/CD8 lineage commitment or survival in the thymus of T-BBS1-/- mice. On the other hand, T-BBS1-/- mice treated with Imiquimod dermally exhibited a significantly higher percentage of CD3-positive splenocytes that was due to CD4 but not CD8 T cell predominance. Notably, we found that T-BBS1-/- mice had significantly decreased wound closure, an effect that was more pronounced in males indicating that the BBSome plays an important role in T cell-mediated skin repair. Together, these findings implicate the BBSome in the regulation of selective functions of T cells.
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Affiliation(s)
- Madeliene Stump
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Physician Scientist Training Program, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Department of Dermatology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Deng Fu Guo
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Veterans Affairs Health Care System, Iowa City, Iowa
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Veterans Affairs Health Care System, Iowa City, Iowa
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
- Obesity Research and Education Initiative, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Abstract
The BBSome is an octameric protein complex involved in Bardet-Biedl syndrome (BBS), a human pleiotropic, autosomal recessive condition. Patients with BBS display various clinical features including obesity, hypertension, and renal abnormalities. Association studies have also linked the BBS genes to hypertension and other cardiovascular risks in the general population. The BBSome was originally associated with the function of cilia, a highly specialized organelle that extend from the cell membrane of most vertebrate cells. However, subsequent studies have implicated the BBSome in the control of a myriad of other cellular processes not related to cilia including cell membrane localization of receptors and gene expression. The development of animal models of BBS such as mouse lines lacking various components of the BBSome and associated proteins has facilitated studying their role in the control of cardiovascular function and deciphering the pathophysiological mechanisms responsible for the cardiovascular aberrations associated with BBS. These studies revealed the importance of the neuronal, renal, vascular, and cardiac BBSome in the regulation of blood pressure, renal function, vascular reactivity, and cardiac development. The BBSome has also emerged as a critical regulator of key systems involved in cardiovascular control including the renin-angiotensin system. Better understanding of the influence of the BBSome on the molecular and physiological processes relevant to cardiovascular health and disease has the potential of identifying novel mechanisms underlying hypertension and other cardiovascular risks.
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Affiliation(s)
- Yuying Zhao
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Human Toxicology Graduate Program, University of Iowa Graduate College, Iowa City, IA, USA
| | - Kamal Rahmouni
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Fraternal Order of Eagles Diabetes Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Obesity Research and Educational Initiative, University of Iowa Carver College of Medicine, Iowa City, IA, USA,Iowa City VA Health Care System, Iowa City, IA, USA,Corresponding author: Kamal Rahmouni, Ph.D., Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA, , Tel: 319 353 5256, Fax: 319 353 5350
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Chandra B, Tung ML, Hsu Y, Scheetz T, Sheffield VC. Retinal ciliopathies through the lens of Bardet-Biedl Syndrome: Past, present and future. Prog Retin Eye Res 2021; 89:101035. [PMID: 34929400 DOI: 10.1016/j.preteyeres.2021.101035] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/15/2022]
Abstract
The primary cilium is a highly specialized and evolutionary conserved organelle in eukaryotes that plays a significant role in cell signaling and trafficking. Over the past few decades tremendous progress has been made in understanding the physiology of cilia and the underlying pathomechanisms of various ciliopathies. Syndromic ciliopathies consist of a group of disorders caused by ciliary dysfunction or abnormal ciliogenesis. These disorders have multiorgan involvement in addition to retinal degeneration underscoring the ubiquitous distribution of primary cilia in different cell types. Genotype-phenotype correlation is often challenging due to the allelic heterogeneity and pleiotropy of these disorders. In this review, we discuss the clinical and genetic features of syndromic ciliopathies with a focus on Bardet-Biedl syndrome (BBS) as a representative disorder. We discuss the structure and function of primary cilia and their role in retinal photoreceptors. We describe the progress made thus far in understanding the functional and genetic characterization including expression quantitative trait locus (eQTL) analysis of BBS genes. In the future directions section, we discuss the emerging technologies, such as gene therapy, as well as anticipated challenges and their implications in therapeutic development for ciliopathies.
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Affiliation(s)
- Bharatendu Chandra
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Moon Ley Tung
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ying Hsu
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Todd Scheetz
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA
| | - Val C Sheffield
- Stead Family Department of Pediatrics, Division of Medical Genetics and Genomics, University of Iowa Carver College of Medicine, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, Iowa City, IA, USA.
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