Research ArticleThioredoxin 1 Plays a Protective Role in Retinas Exposed to Perinatal Hypoxia–Ischemia
Introduction
Thioredoxin (Trx) family proteins are key modulators of cellular redox regulation by controlling the activity of different target proteins through thiol/disulfide exchange reactions (Lee et al., 2013, Meyer et al., 2009) and other oxidative modifications at Cys residues. They depend on specific active site motifs containing one or two cysteine residues; in the case of Trx the conserved Cys-Gly-Pro-Cys motif. Trx was first described by Peter Reichard in Escherichia coli (Laurent et al., 1964). The Trx system includes Trx1 and Trx2 that are localized in the cytosol and in mitochondria, respectively (Meyer et al., 2009, Lee et al., 2013, Hanschmann et al., 2013, Lu and Holmgren, 2014). Trx1 and Trx2 are reduced by Thioredoxin reductase (TrxR) 1 and 2, respectively, with electrons donated from NADPH (Lu and Holmgren, 2014). Trx proteins have been linked to several physiological functions such as regulation of gene expression, proliferation, metabolism and cell death. Via the regulation of specific substrates within signaling circuits, Trx proteins are key regulators of redox signaling. They have also been implicated in various pathological conditions and diseases, including disorders related to inflammation and hypoxia–ischemia (Powis et al., 2000, Iwata et al., 2010, Hanschmann et al., 2013, Zhang et al., 2017). During perinatal hypoxia–ischemia the central nervous system (CNS) is subjected to changes in oxygen levels that lead to the production of reactive species (de Groot and Rauen, 2007, Johnston et al., 2000). In brief, the decrease in the levels of O2 in astrocytes produces a reduction in ATP production that alters membrane polarization due to a reduced activity of the Na+/K+ ATPase pump. Meanwhile, a massive production of glutamate (Glu) in neurons causes the activation of Glu-dependent Ca2+ channels, generating postsynaptic membrane polarization changes. Due to hypoxia, the system consumes part of its antioxidant capacity, and therefore cannot cope with the new influx of O2 during reoxygenation and the generation of different reactive species in the CNS, such as NO*, O2* and H2O2 (de Groot and Rauen, 2007, Ferreiro et al., 2001, Johnston et al., 2000, Johnston et al., 2001, Kalogeris et al., 2012, Uria-Avellanal and Robertson, 2014). We have previously shown that PHI is accompanied with an increase in the protein levels of Trx1 and glutaredoxin (Grx2) in the hippocampus (Romero et al., 2015, Romero et al., 2017). The neural retina is exposed to different levels of reactive species under physiological conditions (Tanito et al., 2002, Lillig and Holmgren, 2007). However, the increase in reactive species induced by a PHI event followed by reperfusion and reoxygenation can lead to neuronal loss and ultimately blindness (Wang et al., 2015). One of the main consequences of PHI in the retina is retinopathy of prematurity (ROP). In places where the neonatal unit has advanced techniques, regarding intensive care, most cases of ROP occur in gestational ages of less than 28 weeks (Holmstrom et al., 2014). ROP comprises changes in retinal neural and vascular development with further compensatory mechanisms (such as an increase in VEGF and vessel growth) that induce aberrant vascularization and can later lead to retinal detachment and blindness (Tsui and Chu, 2017, Zhang et al., 2018). In the present study, we investigated long-term damage of the retina induced by the exposure of new born rats to perinatal hypoxia–ischemia and analyzed the underlying impact of Trx1 in the ARPE-19 cell model. We were able to evidence changes in Trx1 protein levels both in the animal models i.e. perinatal asphyxia model and carotid ligation model, and in ARPE-19 cells due to hypoxia-reoxygenation. Administration of recombinant Trx1 to animals exposed to perinatal hypoxia–ischemia, decreased astrogliosis and improved the delayed neurodevelopment.
Section snippets
Chemicals and reagents
Chemicals and enzymes used in the present work were of analytical grade or better. Unless otherwise noted, reagents were acquired from Sigma-Aldrich (Munich, Germany). SDS-PAGE were run using precasted stain-free gradient (4–20%) gels (Mini PROTEAN TGX, Biorad, Munich, Germany), and the Turbo RTA Transfer Kit with PVDF membranes (Biorad, Munich, Germany) was used for protein transfer. Recombinant Trx1 was expressed and purified via the IMAC principle, as described before (Godoy et al. 2011).
Ethical statement
Perinatal hypoxia–ischemia induces changes in retinal layer thickness, reactive gliosis, and neuronal death and changes in retinal layer thickness
To study perinatal hypoxia–ischemia in vivo, we chose two in vivo rat models, the PA and the carotid ligation (CAR), that constitute two well established and studied models. PHI affects retinal morphology (Rey-Funes et al., 2013) particularly producing changes in layer thickness. We analysed these changes in order to determine the damage caused in our two models. Retinal tissue was subjected to hematoxilin-eosin staining in order to properly preserve and visualize each layer and thus, compare
Perinatal hypoxia–ischemia induced long-term damage to the retina
The CNS is particularly susceptible to hypoxia–ischemia; among the changes caused by the disruption in oxygen and blood flow are neuronal loss and astrogliosis (Bernert et al., 2003, Saraceno et al., 2010). The impact of perinatal hypoxia–ischemia over the CNS is not homogeneous, different areas and cell populations are particularly affected (Laptook et al., 1994, Thompson, 1995). When compared to other tissues in the CNS, it is clear that the retina represents the highest rates in metabolism
Acknowledgments
This work was supported by the Deutsche Forschungsgemeinschaft (SFB593-N01, LI984/3-1, and GRK1947-A1) to CHL, the Federal Ministry for Science and Education (BMBF: 01DN13023-PAREDOX) and MINCYT to CHL and FC, the German Academic Exchange Service DAAD and MINCYT (PROALAR program) to CHL and FC, the (PIP1142010010019, CONICET, Argentina) to FC, and the University of Buenos Aires (UBACYT 20020090100118) to FC. MIH is a fellowship holder from the National Scientific and Technical ResearchCouncil
References (78)
- et al.
Asphyctic lesion: proliferation of tyrosine hydroxylase-immunoreactive nerve cell bodies in the rat substantia nigra and functional changes in dopamine neurotransmission
Brain Res
(1991) - et al.
Protein ubiquitination in postsynaptic densities after hypoxia in rat neostriatum is blocked by hypothermia
Exp Neurol
(2009) - et al.
Norrin treatment improves ganglion cell survival in an oxygen-induced retinopathy model of retinal ischemia
Exp Eye Res
(2017) - et al.
Ischemia-reperfusion injury: processes in pathogenetic networks: a review
Transplant Proc
(2007) - et al.
Long-lasting effects of perinatal asphyxia on exploration, memory and incentive downshift
Int J Dev Neurosci
(2011) - et al.
Redox atlas of the mouse. Immunohistochemical detection of glutaredoxin-, peroxiredoxin-, and thioredoxin-family proteins in various tissues of the laboratory mouse
Biochim Biophys Acta
(2011) - et al.
Both thioredoxin 2 and glutaredoxin 2 contribute to the reduction of the mitochondrial 2-Cys peroxiredoxin Prx3
J Biol Chem
(2010) - et al.
Acylethanolamides and endocannabinoid signaling system in dorsal striatum of rats exposed to perinatal asphyxia
Neurosci Lett
(2017) - et al.
Novel treatments after experimental brain injury
Semin Neonatol
(2000) - et al.
Cell biology of ischemia/reperfusion injury
Int Rev Cell MolBiol
(2012)
Enzymatic synthesis of deoxyribonucleotides. IV. Isolation and characterization of thioredoxin, the hydrogen donor from escherichia coli B
J Biol Chem
Estradiol rescues neurons from global ischemia-induced cell death: multiple cellular pathways of neuroprotection
Steroids
Hypoxic preconditioning induces an AT2-R/VEGFR-2(Flk-1) interaction in the neonatal brain microvasculature for neuroprotection
Neuroscience
Thethioredoxin antioxidant system
Free Radic Biol Med
The role of the redox protein thioredoxin in cell growth and cancer
Free RadicBiol Med
Hypothermia prevents the development of ischemic proliferative retinopathy induced by severe perinatal asphyxia
Exp Eye Res
Thioredoxin 1 and glutaredoxin 2 contribute to maintain the phenotype and integrity of neurons following perinatal asphyxia
Biochim Biophys Acta
Estradiol therapy in adulthood reverses glial and neuronal alterations caused by perinatal asphyxia
Exp Neurol
Regulation of thioredoxin by ceramide in retinal pigment epithelial cells
Exp Eye Res
Perinatal asphyxia induced neuronal loss by apoptosis in the neonatal rat striatum: a combined tunel and stereological study
Exp Neurol
Heterogeneous populations of microglia/macrophages in the retina and their activation after retinal ischemia and reperfusion injury
Exp Eye Res
Targeting the thioredoxin system for cancer therapy
Trends Pharmacol Sci
Thioredoxin 1 and thioredoxin 2 have opposed regulatory functions on hypoxia-inducible factor-1alpha
J Biol Chem.
Oxidative stress promotes proliferation and dedifferentiation of retina glial cells in vitro
J Neurosci Res
High intraocular pressure-induced ischemia and reperfusion injury in the optic nerve and retina in rats
Graefes Arch Clin Exp Ophthalmol
Downregulation of differentiation specific gene expression by oxidative stress in ARPE-19 cells
Invest Ophthalmol Vis Sci
Neurodegeneration, neuronal loss, and neurotransmitter changes in the adult guinea pig with perinatal asphyxia
Pediatr Res
Perinatal asphyxia results in altered expression of the hippocampal acylethanolamide/endocannabinoid signaling system associated to memory impairments in postweaned rats
Front Neuroanat
Alterations in energy metabolism, neuroprotection and visual signal transduction in the retina of parkinsonian, MPTP-treated monkeys
PLoS One
Overexpression of thioredoxins 1 and 2 increases retinal ganglion cell survival after pharmacologically induced oxidative stress, optic nerve transection, and in experimental glaucoma
Trans Am Ophthalmol Soc
The expression of retinal cell markers in human retinal pigment epithelial cells and their augmentation by the synthetic retinoid fenretinide
Mol Vis
Sex differences in mouse hippocampal astrocytes after in-vitro ischemia
J Vis Exp
ARPE-19, A human retinal pigment epithelial cell line with differentiated properties
Exp Eye Res
Deletion of thioredoxin-interacting protein preserves retinal neuronal function by preventing inflammation and vascular injury
Br J Pharmacol
Influence of hypoxia on nitric oxide synthase activity and gene expression in children with congenital heart disease: a novel pathophysiological adaptive mechanism
Circulation
Synapse maturation is enhanced in the binocular region of the retinocollicular map prior to eye opening
J Neurophysiol
Life-long environmental enrichment counteracts spatial learning, reference and working memory deficits in middle-aged rats subjected to perinatal asphyxia
Front Behav Neurosci
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