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Marycz K, Wiatrak B, Irwin-Houston JM, Marcinkowska K, Mularczyk M, Bourebaba L. Sex hormone binding globulin (SHBG) modulates mitochondrial dynamics in PPARγ-depleted equine adipose derived stromal cells. J Mol Med (Berl) 2024:10.1007/s00109-024-02459-z. [PMID: 38874666 DOI: 10.1007/s00109-024-02459-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 03/28/2024] [Accepted: 06/05/2024] [Indexed: 06/15/2024]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor that promotes adipogenesis, lipid uptake and storage, insulin sensitivity, and glucose metabolism. Hence, defects in PPARγ have been associated to the development of metabolic disorders. Sex hormone-binding globulin (SHBG) is a glycoprotein primarily produced in the liver that regulates the bioavailability of sex hormones. Alike PPARγ, low SHBG levels have been correlated with insulin resistance and associated endocrine abnormalities. Therefore, this study aimed to verify whether SHBG may restore depleted PPARγ functions and thus serve as a new candidate for the management of metabolic conditions. A model of equine adipose-derived stromal cells (EqASCs) has been used, in which a PPARγ silencing and SHBG treatment have been achieved to determine the changes in cell viability, premature senescence, oxidative stress, and mitochondrial functions. Obtained data demonstrated that loss in PPARγ triggers cell apoptosis which is not reversed by SHBG application. Moreover, PPARγ knockdown cells exhibited premature senescence, which has been substantially alleviated by SHBG concomitantly to increased BAX/BCL2 ratio, suggesting a possible effect on senescence-induced apoptosis resistance. Interestingly, PPARγ silencing induced a significant alteration in mitochondrial membrane potential as well as the expression of dynamics and metabolism-related markers. SHBG treatment enabled to ameliorate the transmembrane potential, to normalize the expression levels of key dynamics and metabolism mediators, and to restore the protein levels of PINK, which is critically involved in mitochondria recycling machinery. Presented data suggest that SHBG may provide new mechanistic insights into the regulation of PPARγ functions, and thus offers a preliminary picture on a possible SHBG-PPARγ metabolic crosstalk. KEY MESSAGES : PPARγ is a transcription factor that tightly regulates cell metabolism. Low SHBG levels correlate with insulin resistance and associated endocrine abnormalities. PPARγ silencing reduces cell viability, triggers premature senescence and profound mitochondrial failure in equine ASCs. SHBG protein reverses senescent phenotype and apoptosis resistance of PPARγ- ASCs. SHBG improves mitochondrial dynamics and metabolism following PPARγ knockdown. SHBG might serve as a PPARγ potential mimicking agent for the modulation of ASCs metabolic processes.
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Affiliation(s)
- Krzysztof Marycz
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
- International Institute of Translational Medicine, Jesionowa 11, Malin, 55-114, Wisznia Mała, Poland
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, 95516, USA
| | - Benita Wiatrak
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
| | - Jennifer M Irwin-Houston
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
| | - Klaudia Marcinkowska
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
| | - Malwina Mularczyk
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland
- International Institute of Translational Medicine, Jesionowa 11, Malin, 55-114, Wisznia Mała, Poland
| | - Lynda Bourebaba
- Department of Experimental Biology, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Sciences, Norwida 27B, 50-375, Wrocław, Poland.
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Li Y, Tian L, Li S, Chen X, Lei F, Bao J, Wu Q, Wen Y, Jie Y. Disrupted mitochondrial transcription factor A expression promotes mitochondrial dysfunction and enhances ocular surface inflammation by activating the absent in melanoma 2 inflammasome. Free Radic Biol Med 2024; 222:106-121. [PMID: 38797339 DOI: 10.1016/j.freeradbiomed.2024.05.032] [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: 03/28/2024] [Revised: 05/07/2024] [Accepted: 05/17/2024] [Indexed: 05/29/2024]
Abstract
PURPOSE Severe dry eye disease causes ocular surface damage, which is highly associated with mitochondrial dysfunction. Mitochondrial transcription factor A (TFAM) is essential for packaging mitochondrial DNA (mtDNA) and is crucial for maintaining mitochondrial function. Herein, we aimed to explore the effect of a decreased TFAM expression on ocular surface damage. METHODS Female C57BL/6 mice were induced ocular surface injury by topical administrating benzalkonium chloride (BAC). Immortalized human corneal epithelial cells (HCECs) were stimulated by tert-butyl hydroperoxide (t-BHP) to create oxidative stress damage. HCECs with TFAM knockdown were established. RNA sequencing was employed to analyze the whole-genome expression. Mitochondrial changes were measured by transmission electron microscopy, Seahorse metabolic flux analysis, mitochondrial membrane potential, and mtDNA copy number. TFAM expression and inflammatory cytokines were determined using RT-qPCR, immunohistochemistry, immunofluorescence, and immunoblotting. RESULTS In both the corneas of BAC-treated mice and t-BHP-induced HCECs, we observed impaired TFAM expression, accompanied by mitochondrial structure and function defects. TFAM downregulation in HCECs suppressed mitochondrial respiratory capacity, reduced mtDNA content, induced mtDNA leakage into the cytoplasm, and led to inflammation. RNA sequencing revealed the absent in melanoma 2 (AIM2) inflammasome was activated in the corneas of BAC-treated mice. The AIM2 inflammasome activation was confirmed in TFAM knockdown HCECs. TFAM knockdown in t-BHP-stimulated HCECs aggravated mitochondrial dysfunction and the AIM2 inflammasome activation, thereby further triggering the secretion of inflammatory factors such as interleukin (IL) -1β and IL-18. CONCLUSIONS TFAM reduction impaired mitochondrial function, activated AIM2 inflammasome and promoted ocular surface inflammation, revealing an underlying molecular mechanism for ocular surface disorders.
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Affiliation(s)
- Yaqiong Li
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Siyuan Li
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Xiaoniao Chen
- Department of Ophthalmology, The Third Medical Center of Chinese People's Liberation Army General Hospital, Beijing, 100039, China.
| | - Fengyang Lei
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Jiayu Bao
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Qianru Wu
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Ya Wen
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing TongRen Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Sciences, Beijing Tongren Hospital, Capital Medical University, Beijing, 100005, China.
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Costa BLD, Quinn PMJ, Wu WH, Liu S, Nolan ND, Demirkol A, Tsai YT, Caruso SM, Cabral T, Wang NK, Tsang SH. Targeting miR-181a/b in retinitis pigmentosa: implications for disease progression and therapy. Cell Biosci 2024; 14:64. [PMID: 38773556 PMCID: PMC11110387 DOI: 10.1186/s13578-024-01243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 04/30/2024] [Indexed: 05/24/2024] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is a genetically heterogeneous group of degenerative disorders causing progressive vision loss due to photoreceptor death. RP affects other retinal cells, including the retinal pigment epithelium (RPE). MicroRNAs (miRs) are implicated in RP pathogenesis, and downregulating miR-181a/b has shown therapeutic benefit in RP mouse models by improving mitochondrial function. This study investigates the expression profile of miR-181a/b in RPE cells and the neural retina during RP disease progression. We also evaluate how miR-181a/b downregulation, by knocking out miR-181a/b-1 cluster in RPE cells, confers therapeutic efficacy in an RP mouse model and explore the mechanisms underlying this process. RESULTS Our findings reveal distinct expression profiles, with downregulated miR-181a/b in RPE cells suggesting a protective response and upregulated miR-181a/b in the neural retina indicating a role in disease progression. We found that miR-181a/b-2, encoded in a separate genomic cluster, compensates for miR-181a/b-1 ablation in RPE cells at late time points. The transient downregulation of miR-181a/b in RPE cells at post-natal week 6 (PW6) led to improved RPE morphology, retarded photoreceptor degeneration and decreased RPE aerobic glycolysis. CONCLUSIONS Our study elucidates the underlying mechanisms associated with the therapeutic modulation of miR-181a/b, providing insights into the metabolic processes linked to its RPE-specific downregulation. Our data further highlights the impact of compensatory regulation between miR clusters with implications for the development of miR-based therapeutics.
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Affiliation(s)
- Bruna Lopes da Costa
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Peter M J Quinn
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Wen-Hsuan Wu
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Siyuan Liu
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Nicholas D Nolan
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Aykut Demirkol
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yi-Ting Tsai
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Salvatore Marco Caruso
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | - Thiago Cabral
- Department of Specialized Medicine, CCS and Vision Center Unit, Ophthalmology EBSERH, HUCAM/CCS, UFES-Federal University of Espírito Santo (UFES), Vitória, Brazil
- Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), São Paulo, Brazil
| | - Nan-Kai Wang
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care (JCVC) and Barbara & Donald Jonas Stem Cell Laboratory, New York-Presbyterian Hospital, New York, NY, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, USA.
- Columbia Stem Cell Initiative, Institute of Human Nutrition ,Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY, USA.
- Columbia University Irving Medical Center, Hammer Health Sciences Center 205b, 701 West 168th Street, New York, NY, 10032, USA.
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Teh MR, Armitage AE, Drakesmith H. Why cells need iron: a compendium of iron utilisation. Trends Endocrinol Metab 2024:S1043-2760(24)00109-7. [PMID: 38760200 DOI: 10.1016/j.tem.2024.04.015] [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: 03/15/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 05/19/2024]
Abstract
Iron deficiency is globally prevalent, causing an array of developmental, haematological, immunological, neurological, and cardiometabolic impairments, and is associated with symptoms ranging from chronic fatigue to hair loss. Within cells, iron is utilised in a variety of ways by hundreds of different proteins. Here, we review links between molecular activities regulated by iron and the pathophysiological effects of iron deficiency. We identify specific enzyme groups, biochemical pathways, cellular functions, and cell lineages that are particularly iron dependent. We provide examples of how iron deprivation influences multiple key systems and tissues, including immunity, hormone synthesis, and cholesterol metabolism. We propose that greater mechanistic understanding of how cellular iron influences physiological processes may lead to new therapeutic opportunities across a range of diseases.
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Affiliation(s)
- Megan R Teh
- MRC Translational Immune Discovery Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrew E Armitage
- MRC Translational Immune Discovery Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Hal Drakesmith
- MRC Translational Immune Discovery Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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Nakai A, Lee D, Shoda C, Negishi K, Nakashizuka H, Yamagami S, Kurihara T. Modulation of Hypoxia-Inducible Factors and Vascular Endothelial Growth Factor Expressions by Superfood Camu-Camu ( Myrciaria dubia) Treatment in ARPE-19 and Fetal Human RPE Cells. J Ophthalmol 2023; 2023:6617981. [PMID: 38187496 PMCID: PMC10771337 DOI: 10.1155/2023/6617981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/30/2023] [Accepted: 12/15/2023] [Indexed: 01/09/2024] Open
Abstract
Background Anti-vascular endothelial growth factor (anti-VEGF) therapy via intravitreal injection is an effective treatment for patients with abnormal ocular neovascularization, such as age-related macular degeneration (AMD) and diabetic macular edema (DME). However, prolonged and frequent anti-VEGF treatment is associated with a risk of local and systemic adverse events, including geographic atrophy, cerebrovascular disease, and death. Furthermore, some patients do not adequately respond to anti-VEGF therapy. Hypoxia-inducible factor (HIF) is a transcription factor that controls the expression of hypoxia-responsive genes involved in angiogenesis, inflammation, and metabolism. The HIF/VEGF pathway plays an important role in neovascularization, and the inhibition of HIF activation could be an effective biomolecular target for neovascular diseases. The demand for disease prevention or treatment using functional foods such as superfoods has increased in recent years. Few reports to date have focused on the antineovascular effects of superfoods in the retinal pigment epithelium (RPE). In light of the growing demand for functional foods, we aimed to find novel HIF inhibitors from superfoods worked in RPE cells, which could be an adjuvant for anti-VEGF therapy. Methods Seven superfoods were examined to identify novel HIF inhibitor candidates using luciferase assay screening. We used the human RPE cell line ARPE-19 and fetal human RPE (fhRPE) to investigate the biomolecular actions of novel HIF inhibitors using quantitative PCR and western blotting. Results Under CoCl2-induced pseudohypoxic condition and 1% oxygen hypoxic incubation, camu-camu (Myrciaria dubia) showed HIF inhibitory effects determined by luciferase assays. Camu-camu downregulated HIF-1α and VEGFA mRNA expressions in a concentration-dependent manner. Camu-camu also inhibited HIF-1α protein expressions, and its inhibitory effect was greater than that of vitamin C, which is present at high levels in camu-camu. Conclusion The camu-camu extract suppressed the activation of HIF and VEGF in RPE cells. This could assist anti-VEGF therapy in patients with abnormal ocular neovascularization.
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Affiliation(s)
- Ayaka Nakai
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Nihon University School of Medicine, Tokyo, Japan
| | - Deokho Lee
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Chiho Shoda
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Nihon University School of Medicine, Tokyo, Japan
| | - Kazuno Negishi
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | | | - Satoru Yamagami
- Ophthalmology, Nihon University School of Medicine, Tokyo, Japan
| | - Toshihide Kurihara
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Japan
- Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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Zhao J, Kim HJ, Montenegro D, Dunaief JL, Sparrow JR. Iron overload and chelation modulates bisretinoid levels in the retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1305864. [PMID: 38983013 PMCID: PMC11182296 DOI: 10.3389/fopht.2023.1305864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 12/07/2023] [Indexed: 07/11/2024]
Abstract
Aim Iron dysregulation in conjunction with other disease processes may exacerbate retinal degeneration. We employed models of iron overload and iron chelation to explore the interactions between iron-catalyzed oxidation and photoreactive bisretinoid lipofuscin. Methods The mice were injected intravitreally with ferric ammonium citrate (FAC) or were treated using the iron chelator deferiprone (DFP) from birth to 2 months of age. Short-wavelength fundus autofluorescence (SW-AF) and spectral-domain optical coherence tomography (SD-OCT) scans were acquired. The bisretinoid levels were quantified using ultra performance liquid chromatography (UPLC) and in vivo through quantitative fundus autofluorescence (qAF). In histologic sections, the photoreceptor cell viability was assessed by measuring the thickness of the outer nuclear layer (ONL). Results The levels of bisretinoids, all-trans-retinal dimers, and A2PE were significantly increased in the FAC-injected eyes of C57BL/6J mice. Seven days after FAC injection, hyperautofluorescent foci were visible in fundus autofluorescence (488 nm) images, and in SD-OCT scans, aberrant hyperreflectivity was present in the outer retina and ONL thinning was observed. In FAC-injected Abca4-/- mice with pronounced RPE bisretinoid lipofuscin accumulation, the hyperautofluorescent puncta were more abundant than in the wild-type mice, and the extent of ONL thinning was greater. Conversely, the intravitreal injection of FAC in Mertk-/- mice led to a more modest increase in A2PE after 2 days. In contrast to the effect of iron accumulation, chelation with DFP resulted in significantly increased levels of A2E and A2-GPE and qAF due to the reduced iron-catalyzed oxidation of bisretinoids. In Mertk-/- mice, the A2E level was significantly lower and the ONL area was smaller than in DFP-treated mice. DFP chelation did not impair the visual cycle in BALB/cJ mice. Conclusion Iron accumulation was associated with progressive impairment in photoreceptor cells that was associated with the increased formation of a bisretinoid species known to form in photoreceptor outer segments as a precursor to A2E. Additionally, disease features such as the development of hyperautofluorescence puncta in fundus AF images, hyperreflectivity in the outer retina of SD-OCT scans, and ONL thinning were more pronounced when iron was delivered to Abca4-/- mice with a greater propensity for bisretinoid formation. Higher bisretinoid levels and enhanced qAF are indicative of lesser bisretinoid loss due to oxidation.
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Affiliation(s)
- Jin Zhao
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Hye Jin Kim
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Diego Montenegro
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
| | - Josh L Dunaief
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University Medical Center, New York, NY, United States
- Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
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Hass DT, Zhang Q, Autterson GA, Bryan RA, Hurley JB, Miller JML. Medium Depth Influences O2 Availability and Metabolism in Human RPE Cultures. Invest Ophthalmol Vis Sci 2023; 64:4. [PMID: 37922158 PMCID: PMC10629522 DOI: 10.1167/iovs.64.14.4] [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: 05/14/2023] [Accepted: 10/13/2023] [Indexed: 11/05/2023] Open
Abstract
Purpose Retinal pigment epithelium (RPE) oxidative metabolism is critical for normal retinal function and is often studied in cell culture systems. Here, we show that conventional culture media volumes dramatically impact O2 availability, limiting oxidative metabolism. We suggest optimal conditions to ensure cultured RPE is in a normoxic environment permissive to oxidative metabolism. Methods We altered the availability of O2 to human primary and induced pluripotent stem cell-derived RPE cultures directly via a hypoxia chamber or indirectly via the amount of medium over cells. We measured oxygen consumption rates (OCRs), glucose consumption, lactate production, 13C6-glucose and 13C5-glutamine flux, hypoxia inducible factor 1α (HIF-1α) stability, intracellular lipid droplets after a lipid challenge, transepithelial electrical resistance, cell morphology, and pigmentation. Results Medium volumes commonly employed during RPE culture limit diffusion of O2 to cells, triggering hypoxia, activating HIF-1α, limiting OCR, and dramatically altering cell metabolism, with only minor effects on typical markers of RPE health. Media volume effects on O2 availability decrease acetyl-CoA utilization, increase glycolysis and reductive carboxylation, and alter the size and number of intracellular lipid droplets under lipid-rich conditions. Conclusions Despite having little impact on visible and typical markers of RPE culture health, media volume dramatically affects RPE physiology "under the hood." As RPE-centric diseases like age-related macular degeneration involve oxidative metabolism, RPE cultures need to be optimized to study such diseases. We provide guidelines for optimal RPE culture volumes that balance ample nutrient availability from larger media volumes with adequate O2 availability seen with smaller media volumes.
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Affiliation(s)
- Daniel T. Hass
- Department of Biochemistry, The University of Washington, Seattle, Washington, United States
| | - Qitao Zhang
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
| | | | | | - James B. Hurley
- Department of Biochemistry, The University of Washington, Seattle, Washington, United States
| | - Jason M. L. Miller
- Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, United States
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Musa M, Zeppieri M, Atuanya GN, Enaholo ES, Topah EK, Ojo OM, Salati C. Nutritional Factors: Benefits in Glaucoma and Ophthalmologic Pathologies. Life (Basel) 2023; 13:life13051120. [PMID: 37240765 DOI: 10.3390/life13051120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/17/2023] [Accepted: 04/26/2023] [Indexed: 05/19/2023] Open
Abstract
Glaucoma is a chronic optic neuropathy that can lead to irreversible functional and morphological damage if left untreated. The gold standard therapeutic approaches in managing patients with glaucoma and limiting progression include local drops, laser, and/or surgery, which are all geared at reducing intraocular pressure (IOP). Nutrients, antioxidants, vitamins, organic compounds, and micronutrients have been gaining increasing interest in the past decade as integrative IOP-independent strategies to delay or halt glaucomatous retinal ganglion cell degeneration. In our minireview, we examine the various nutrients and compounds proposed in the current literature for the management of ophthalmology diseases, especially for glaucoma. With respect to each substance considered, this minireview reports the molecular and biological characteristics, neuroprotective activities, antioxidant properties, beneficial mechanisms, and clinical studies published in the past decade in the field of general medicine. This study highlights the potential benefits of these substances in glaucoma and other ophthalmologic pathologies. Nutritional supplementation can thus be useful as integrative IOP-independent strategies in the management of glaucoma and in other ophthalmologic pathologies. Large multicenter clinical trials based on functional and morphologic data collected over long follow-up periods in patients with IOP-independent treatments can pave the way for alternative and/or coadjutant therapeutic options in the management of glaucoma and other ocular pathologies.
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Affiliation(s)
- Mutali Musa
- Department of Optometry, University of Benin, Benin City 300238, Edo State, Nigeria
| | - Marco Zeppieri
- Department of Ophthalmology, University Hospital of Udine, 33100 Udine, Italy
| | | | | | - Efioshiomoshi Kings Topah
- Department of Optometry, Faculty of Allied Health Sciences, College of Health Sciences Bayero University, Kano 700006, Kano State, Nigeria
| | - Oluwasola Michael Ojo
- School of Optometry and Vision Sciences, College of Health Sciences, University of Ilorin, Ilorin 240003, Kwara State, Nigeria
| | - Carlo Salati
- Department of Ophthalmology, University Hospital of Udine, 33100 Udine, Italy
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Rosin B, Sahel J. Lifting the iron curtain of vision. EMBO Mol Med 2023; 15:e17259. [PMID: 36715217 PMCID: PMC9906325 DOI: 10.15252/emmm.202217259] [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: 01/04/2023] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/31/2023] Open
Abstract
Ocular and specifically retinal toxicities of systemic medications are prevalent and encompass many disease modalities. For many of these pharmaceuticals, established follow-up protocols are in place to ensure timely detection and cessation of therapy. However, while for some disorders, cessation of therapy is a viable option due to existing treatment alternatives, for some others cessation of treatment can be life threatening and/or shorten the patient's life expectancy. Such is the case for iron chelating agents used in transfusion-dependent patients of Thalassemia, of which deferoxamine (DFO) is the most widely used. In their recent article in EMBO Molecular Medicine, Kong et al (2023) addressed the issue of DFO-induced retinal toxicity used both in vivo and in vitro techniques. Their study suggests a potentially protective role for α-ketoglutarate (AKG) supplementation against DFO toxicity.
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Affiliation(s)
- Boris Rosin
- Department of Ophthalmology/UPMC Eye CenterUniversity of PittsburghPittsburghPAUSA
| | - Jose‐Alain Sahel
- Department of Ophthalmology/UPMC Eye CenterUniversity of PittsburghPittsburghPAUSA
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