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Sreekumar PG, Ferrington DA, Kannan R. Glutathione Metabolism and the Novel Role of Mitochondrial GSH in Retinal Degeneration. Antioxidants (Basel) 2021; 10:661. [PMID: 33923192 PMCID: PMC8146950 DOI: 10.3390/antiox10050661] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/18/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023] Open
Abstract
Glutathione (GSH) is present ubiquitously, and its role as a crucial cellular antioxidant in tissues, including the retina, is well established. GSH's antioxidant function arises from its ability to scavenge reactive oxygen species or to serve as an essential cofactor for GSH S-transferases and peroxidases. This review summarizes the general functions, retinal distribution, disorders linked to GSH deficiency, and the emerging role for mitochondrial GSH (mGSH) in retinal function. Though synthesized only in the cytosol, the presence of GSH in multiple cell organelles suggests the requirement for its active transport across organellar membranes. The localization and distribution of 2-oxoglutarate carrier (OGC) and dicarboxylate carrier (DIC), two recently characterized mitochondrial carrier proteins in RPE and retina, show that these transporters are highly expressed in human retinal pigment epithelium (RPE) cells and retinal layers, and their expression increases with RPE polarity in cultured cells. Depletion of mGSH levels via inhibition of the two transporters resulted in reduced mitochondrial bioenergetic parameters (basal respiration, ATP production, maximal respiration, and spare respiratory capacity) and increased RPE cell death. These results begin to reveal a critical role for mGSH in maintaining RPE bioenergetics and cell health. Thus, augmentation of mGSH pool under GSH-deficient conditions may be a valuable tool in treating retinal disorders, such as age-related macular degeneration and optic neuropathies, whose pathologies have been associated with mitochondrial dysfunction.
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Affiliation(s)
- Parameswaran G. Sreekumar
- The Stephen J. Ryan Initiative for Macular Research (RIMR), Doheny Eye Institute, Los Angeles, CA 90033, USA;
| | - Deborah A. Ferrington
- Department of Ophthalmology and Visual Neurosciences and Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA;
| | - Ram Kannan
- The Stephen J. Ryan Initiative for Macular Research (RIMR), Doheny Eye Institute, Los Angeles, CA 90033, USA;
- Stein Eye Institute, Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Fernandez A, Matias N, Fucho R, Ribas V, Von Montfort C, Nuño N, Baulies A, Martinez L, Tarrats N, Mari M, Colell A, Morales A, Dubuquoy L, Mathurin P, Bataller R, Caballeria J, Elena M, Balsinde J, Kaplowitz N, Garcia-Ruiz C, Fernandez-Checa JC. ASMase is required for chronic alcohol induced hepatic endoplasmic reticulum stress and mitochondrial cholesterol loading. J Hepatol 2013; 59:805-13. [PMID: 23707365 PMCID: PMC3779525 DOI: 10.1016/j.jhep.2013.05.023] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 05/07/2013] [Accepted: 05/13/2013] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS The pathogenesis of alcohol-induced liver disease (ALD) is poorly understood. Here, we examined the role of acid sphingomyelinase (ASMase) in alcohol induced hepatic endoplasmic reticulum (ER) stress, a key mechanism of ALD. METHODS We examined ER stress, lipogenesis, hyperhomocysteinemia, mitochondrial cholesterol (mChol) trafficking and susceptibility to LPS and concanavalin-A in ASMase(-)(/-) mice fed alcohol. RESULTS Alcohol feeding increased SREBP-1c, DGAT-2, and FAS mRNA in ASMase(+/+) but not in ASMase(-/-) mice. Compared to ASMase(+/+) mice, ASMase(-/-) mice exhibited decreased expression of ER stress markers induced by alcohol, but the level of tunicamycin-mediated upregulation of ER stress markers and steatosis was similar in both types of mice. The increase in homocysteine levels induced by alcohol feeding was comparable in both ASMase(+/+) and ASMase(-/-) mice. Exogenous ASMase, but not neutral SMase, induced ER stress by perturbing ER Ca(2+) homeostasis. Moreover, alcohol-induced mChol loading and StARD1 overexpression were blunted in ASMase(-/-) mice. Tunicamycin upregulated StARD1 expression and this outcome was abrogated by tauroursodeoxycholic acid. Alcohol-induced liver injury and sensitization to LPS and concanavalin-A were prevented in ASMase(-/-) mice. These effects were reproduced in alcohol-fed TNFR1/R2(-/-) mice. Moreover, ASMase does not impair hepatic regeneration following partial hepatectomy. Of relevance, liver samples from patients with alcoholic hepatitis exhibited increased expression of ASMase, StARD1, and ER stress markers. CONCLUSIONS Our data indicate that ASMase is critical for alcohol-induced ER stress, and provide a rationale for further clinical investigation in ALD.
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Affiliation(s)
- Anna Fernandez
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Núria Matias
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Raquel Fucho
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Vicente Ribas
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Claudia Von Montfort
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Natalia Nuño
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Anna Baulies
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Laura Martinez
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Núria Tarrats
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Montserrat Mari
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Anna Colell
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Albert Morales
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Laurent Dubuquoy
- Université Lille Nord de France, and Service des Maladies de l'Appareil Digestif, Hôpital Huriez, Lille, France; Unité 995, Institut National de la Santé et de la Recherche Médicale, Lille, France
| | - Philippe Mathurin
- Université Lille Nord de France, and Service des Maladies de l'Appareil Digestif, Hôpital Huriez, Lille, France; Unité 995, Institut National de la Santé et de la Recherche Médicale, Lille, France
| | - Ramón Bataller
- Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | - Joan Caballeria
- Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain
| | | | - Jesus Balsinde
- Institut of Molecular Biology and Genetics, CSIC-CIBERDEM, Valladolid, Spain
| | - Neil Kaplowitz
- Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033
| | - Carmen Garcia-Ruiz
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain,Carmen Garcia-Ruiz and Jose C Fernandez-Checa share senior authorship. Correspondence addressed to Jose C Fernandez-Checa,
| | - Jose C. Fernandez-Checa
- Department of Cell Death and Proliferation, IIBB-CSIC,Liver Unit-Hospital Clinic-IDIBAPS, and CIBEREHD, Barcelona, Spain,Southern California Research Center for ALPD and Cirrhosis, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033,Carmen Garcia-Ruiz and Jose C Fernandez-Checa share senior authorship. Correspondence addressed to Jose C Fernandez-Checa,
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