bims-mideyd 2021-12-26 papers

bims-mideyd

Biomed News

on Mitochondrial dysfunction in eye diseases

Issue of 2021–12–26
twelve papers selected by
Rajalekshmy “Raji” Shyam, Indiana University Bloomington

mTOR Inhibition via Rapamycin Treatment Partially Reverts the Deficit in Energy Metabolism Caused by FH Loss in RPE Cells.
Modulation of Sirt1-mTORC1 Pathway in Microglia Attenuates Retinal Ganglion Cell Loss After Optic Nerve Injury.
Role of Oxidative Stress in Ocular Diseases Associated with Retinal Ganglion Cells Degeneration.
Cannabinol modulates neuroprotection and intraocular pressure: A potential multi-target therapeutic intervention for glaucoma.
The Protective Effects of α-Mangostin Attenuate Sodium Iodate-Induced Cytotoxicity and Oxidative Injury via Mediating SIRT-3 Inactivation via the PI3K/AKT/PGC-1α Pathway.
Reintroduction of DJ-1 in Müller Cells Inhibits Retinal Degeneration in the DJ-1 Deficient Retina.
Overexpression of CERKL Protects Retinal Pigment Epithelium Mitochondria from Oxidative Stress Effects.
Mammalian Target of Rapamycin Inhibitor Rapamycin Alleviates 7-Ketocholesterol Induced Inflammatory Responses and Vascular Endothelial Growth Factor Elevation by Regulating MAPK Pathway in Human Retinal Pigment Epithelium Cells.
The Role of Oxidative Stress and Therapeutic Potential of Antioxidants in Graves' Ophthalmopathy.
Potential Combination Drug Therapy to Prevent Redox Stress and Mitophagy Dysregulation in Retinal Müller Cells under High Glucose Conditions: Implications for Diabetic Retinopathy.
Omega-3 fatty acids promote neuroprotection, decreased apoptosis and reduced glial cell activation in the retina of a mouse model of OPA1-related autosomal dominant optic atrophy.
Hydroxysafflor yellow A and anhydrosafflor yellow B alleviate ferroptosis and parthanatos in PC12 cells injured by OGD/R.

Antioxidants (Basel). 2021 Dec 03. pii: 1944. [Epub ahead of print]10(12):

mTOR Inhibition via Rapamycin Treatment Partially Reverts the Deficit in Energy Metabolism Caused by FH Loss in RPE Cells.

David A Merle, Francesca Provenzano, Mohamed Ali Jarboui, Ellen Kilger, Simon J Clark, Michela Deleidi, Angela Armento, Marius Ueffing.

  Age-related macular degeneration (AMD) is a complex degenerative disease of the retina with multiple risk-modifying factors, including aging, genetics, and lifestyle choices. The combination of these factors leads to oxidative stress, inflammation, and metabolic failure in the retinal pigment epithelium (RPE) with subsequent degeneration of photoreceptors in the retina. The alternative complement pathway is tightly linked to AMD. In particular, the genetic variant in the complement factor H gene (CFH), which leads to the Y402H polymorphism in the factor H protein (FH), confers the second highest risk for the development and progression of AMD. Although the association between the FH Y402H variant and increased complement system activation is known, recent studies have uncovered novel FH functions not tied to this activity and highlighted functional relevance for intracellular FH. In our previous studies, we show that loss of CFH expression in RPE cells causes profound disturbances in cellular metabolism, increases the vulnerability towards oxidative stress, and modulates the activation of pro-inflammatory signaling pathways, most importantly the NF-kB pathway. Here, we silenced CFH in hTERT-RPE1 cells to investigate the mechanism by which intracellular FH regulates RPE cell homeostasis. We found that silencing of CFH results in hyperactivation of mTOR signaling along with decreased mitochondrial respiration and that mTOR inhibition via rapamycin can partially rescue these metabolic defects. To obtain mechanistic insight into the function of intracellular FH in hTERT-RPE1 cells, we analyzed the interactome of FH via immunoprecipitation followed by mass spectrometry-based analysis. We found that FH interacts with essential components of the ubiquitin-proteasomal pathway (UPS) as well as with factors associated with RB1/E2F signalling in a complement-pathway independent manner. Moreover, we found that FH silencing affects mRNA levels of the E3 Ubiquitin-Protein Ligase Parkin and PTEN induced putative kinase (Pink1), both of which are associated with UPS. As inhibition of mTORC1 was previously shown to result in increased overall protein degradation via UPS and as FH mRNA and protein levels were shown to be affected by inhibition of UPS, our data stress a potential regulatory link between endogenous FH activity and the UPS.

Keywords:  age-related macular degeneration (AMD); complement factor H (CFH/FH); interactome; mammalian target of rapamycin (mTOR); mitochondrial respiration; retinal pigment epithelium (RPE) cells; ubiquitin-proteasomal pathway

DOI:  https://doi.org/10.3390/antiox10121944
J Inflamm Res. 2021 ;14 6857-6869

Modulation of Sirt1-mTORC1 Pathway in Microglia Attenuates Retinal Ganglion Cell Loss After Optic Nerve Injury.

Qianxue Mou, Ke Yao, Meng Ye, Bowen Zhao, Yuanyuan Hu, Xiaotong Lou, Huixia Li, Hong Zhang, Yin Zhao.

   Purpose: Optic nerve injury (ONI) causes neuroinflammation and neurodegeneration leading to visual deficits. The response of microglia has emerged as an impactful component of etiology in neurodegeneration. This study aimed to investigate the effect of SIRT1-mTORC1 signaling pathway in microglia regulation after ONI.
Methods: Cx3Cr1-CreERT2/Raptor F/F and Cx3Cr1-CreERT2/Sirt1 F/F mice were used to delete Raptor and Sirt1 in microglia, respectively. Optic nerve crush (ONC) model was established to mimic ONI. PLX5622, a highly specific inhibitor of the colony-stimulating factor 1 receptor (CSF1R), is used to eliminate microglia in optic nerve. Ionized calcium binding adaptor molecule 1 (Iba1) immunostaining was used to detect microglial activation. Retinal ganglion cells (RGCs) were quantified by Nissl staining and retinal whole-mount immunostaining with RNA-binding protein with multiple splicing (RBPMS). Axonal damage was valued by transmission electron microscopy (TEM).
Results: Microglial activation emerged on day 3 post ONC and was earlier than RGCs loss which occurred at day 5 after injury. Depleting microglia with PLX5622 could attenuate the loss of RGCs and axon damage after ONC. Gain- and loss-of-function studies revealed that SIRT1 determined the activation of microglia in optic nerve. In addition, microglia-specific deletion of Raptor resulted in decreased microglial activation. Interestingly, activating mTORC1 with CCT007093 could reverse the function of SIRT1 in regulating the process of microglial activation mediated RGCs loss.
Conclusion: Our study reveals a potential novel mechanism of SIRT1-mTORC1 pathway in microglia regulation, and indicates a therapeutic potential for the protection of RGCs in ONI.

Keywords:  SIRT1; mTORC1; microglia; optic nerve injury; retinal ganglion cells

DOI:  https://doi.org/10.2147/JIR.S338815
Antioxidants (Basel). 2021 Dec 05. pii: 1948. [Epub ahead of print]10(12):

Role of Oxidative Stress in Ocular Diseases Associated with Retinal Ganglion Cells Degeneration.

Eugene Yu-Chuan Kang, Pei-Kang Liu, Yao-Tseng Wen, Peter M J Quinn, Sarah R Levi, Nan-Kai Wang, Rong-Kung Tsai.

  Ocular diseases associated with retinal ganglion cell (RGC) degeneration is the most common neurodegenerative disorder that causes irreversible blindness worldwide. It is characterized by visual field defects and progressive optic nerve atrophy. The underlying pathophysiology and mechanisms of RGC degeneration in several ocular diseases remain largely unknown. RGCs are a population of central nervous system neurons, with their soma located in the retina and long axons that extend through the optic nerve to form distal terminals and connections in the brain. Because of this unique cytoarchitecture and highly compartmentalized energy demand, RGCs are highly mitochondrial-dependent for adenosine triphosphate (ATP) production. Recently, oxidative stress and mitochondrial dysfunction have been found to be the principal mechanisms in RGC degeneration as well as in other neurodegenerative disorders. Here, we review the role of oxidative stress in several ocular diseases associated with RGC degenerations, including glaucoma, hereditary optic atrophy, inflammatory optic neuritis, ischemic optic neuropathy, traumatic optic neuropathy, and drug toxicity. We also review experimental approaches using cell and animal models for research on the underlying mechanisms of RGC degeneration. Lastly, we discuss the application of antioxidants as a potential future therapy for the ocular diseases associated with RGC degenerations.

Keywords:  degeneration; glaucoma; hereditary optic atrophy; ischemic optic neuropathy; mitochondria; optic neuritis; oxidative stress; retinal ganglion cell; traumatic optic neuropathy

DOI:  https://doi.org/10.3390/antiox10121948
Biochim Biophys Acta Mol Basis Dis. 2021 Dec 16. pii: S0925-4439(21)00258-1. [Epub ahead of print]1868(3): 166325

Cannabinol modulates neuroprotection and intraocular pressure: A potential multi-target therapeutic intervention for glaucoma.

Rishi K Somvanshi, Shenglong Zou, Salam Kadhim, Sapna Padania, Eric Hsu, Ujendra Kumar.

   OBJECTIVES: Glaucoma is characterized by progressive damage of the retinal ganglion cells (RGCs), resulting in irreversible vision loss. Cannabinoids (CBs) ameliorate several factors that contribute to the progression of glaucoma, including increased intraocular pressure (IOP), degeneration of RGC and optical nerve (ON) damage. However, a direct correlation of specific CBs with the molecular events pertaining to glaucoma pathology is not well established. Therefore, this study aims to evaluate the role of cannabinol (CBN) on RGC protection, modulation of IOP, and its effects on the level of extracellular matrix (ECM) proteins using both in vitro and in vivo models of glaucoma.
METHODS AND RESULTS: When exposed to elevated hydrostatic pressure, CBN, in a dose-dependent manner, protected differentiated mouse 661W retinal ganglion precursor-like cells from pressure-induced toxicity. In human trabecular meshwork cells (hTM), CBN attenuated changes in the ECM proteins, including fibronectin and α-smooth muscle actin (α-SMA), as well as mitogen-activated protein kinases (phospho-ERK1/2) in the presence or absence of transforming growth factor-beta 2 (TGF-β2) induced stress. Ocular pharmacokinetic parameters were evaluated post-intravitreal (IVT) CBN delivery in vivo. Furthermore, we demonstrated that IVT-administered CBN improved pattern electroretinogram (pERG) amplitudes and reduced IOP in a rat episcleral vein laser photocoagulation model of glaucoma.
CONCLUSION: CBN promotes neuroprotection, abrogates changes in ECM protein, and normalizes the IOP levels in the eye. Therefore, our observations in the present study indicate a therapeutic potential for CBN in the treatment of glaucoma.

Keywords:  Cannabinol; Glaucoma; Intraocular pressure; Neuroprotection; Pattern electroretinogram; Retinal ganglion cells; Trabecular meshwork

DOI:  https://doi.org/10.1016/j.bbadis.2021.166325
Antioxidants (Basel). 2021 Nov 24. pii: 1870. [Epub ahead of print]10(12):

The Protective Effects of α-Mangostin Attenuate Sodium Iodate-Induced Cytotoxicity and Oxidative Injury via Mediating SIRT-3 Inactivation via the PI3K/AKT/PGC-1α Pathway.

Chen-Ju Chuang, Meilin Wang, Jui-Hsuan Yeh, Tzu-Chun Chen, Shang-Chun Tsou, Yi-Ju Lee, Yuan-Yen Chang, Hui-Wen Lin.

  It is well known that age-related macular degeneration (AMD) is an irreversible neurodegenerative disease that can cause blindness in the elderly. Oxidative stress-induced retinal pigment epithelial (RPE) cell damage is a part of the pathogenesis of AMD. In this study, we evaluated the protective effect and mechanisms of alpha-mangostin (α-mangostin, α-MG) against NaIO3-induced reactive oxygen species (ROS)-dependent toxicity, which activates apoptosis in vivo and in vitro. MTT assay and flow cytometry demonstrated that the pretreatment of ARPE-19 cells with α-MG (0, 3.75, 7.5, and 15 μM) significantly increased cell viability and reduced apoptosis from NaIO3-induced oxidative stress in a concentration-dependent manner, which was achieved by the inhibition of Bax, cleaved PARP-1, cleaved caspase-3 protein expression, and enhancement of Bcl-2 protein. Furthermore, pre-incubation of ARPE-19 cells with α-MG markedly inhibited the intracellular ROS and extracellular H2O2 generation via blocking of the abnormal enzyme activities of superoxide dismutase (SOD), the downregulated levels of catalase (CAT), and the endogenous antioxidant, glutathione (GSH), which were regulated by decreasing PI3K-AKT-PGC-1α-STRT-3 signaling in ARPE-19 cells. In addition, our in vivo results indicated that α-MG improved retinal deformation and increased the thickness of both the outer nuclear layer and inner nuclear layer by inhibiting the expression of cleaved caspase-3 protein. Taken together, our results suggest that α-MG effectively protects human ARPE-19 cells from NaIO3-induced oxidative damage via antiapoptotic and antioxidant effects.

Keywords:  age-related macular degeneration (AMD); alpha-mangostin (α-MG); antiapoptotic; antioxidant; oxidative stress; retinal pigment epithelial (RPE)

DOI:  https://doi.org/10.3390/antiox10121870
Antioxidants (Basel). 2021 Nov 23. pii: 1862. [Epub ahead of print]10(12):

Reintroduction of DJ-1 in Müller Cells Inhibits Retinal Degeneration in the DJ-1 Deficient Retina.

Naouel Gharbi, Dagne Røise, Jorunn-Elise Førre, Amanda J Edson, Helena A Hushagen, Valentina Tronci, Ann-Kristin Frøyset, Kari E Fladmark.

  The eye is continuously under oxidative stress due to high metabolic activity and reactive oxygen species generated by daily light exposure. The redox-sensitive protein DJ-1 has proven to be essential in order to protect retina and retinal pigment epithelium (RPE) from oxidative-stress-induced degeneration. Here, we analyzed the specific role of Müller cell DJ-1 in the adult zebrafish retina by re-establishing Müller-cell-specific DJ-1 expression in a DJ-1 knockout retina. Loss of DJ-1 resulted in an age-dependent retinal degeneration, including loss of cells in the ganglion cell layer, retinal thinning, photoreceptor disorganization and RPE cell dysfunction. The degenerative phenotype induced by the absence of DJ-1 was inhibited by solely expressing DJ-1 in Müller cells. The protective effect was dependent upon the cysteine-106 residue of DJ-1, which has been shown to be an oxidative sensor of DJ-1. In a label-free proteomics analysis of isolated retinas, we identified proteins differentially expressed after DJ-1 knockout, but with restored levels after Müller cell DJ-1 re-insertion. Our data show that Müller cell DJ-1 has a major role in protecting the retina from age-dependent oxidative stress.

Keywords:  DJ-1; Müller cell; neurodegeneration; oxidative stress; retina

DOI:  https://doi.org/10.3390/antiox10121862
Antioxidants (Basel). 2021 Dec 19. pii: 2018. [Epub ahead of print]10(12):

Overexpression of CERKL Protects Retinal Pigment Epithelium Mitochondria from Oxidative Stress Effects.

Rocío García-Arroyo, Aleix Gavaldà-Navarro, Francesc Villarroya, Gemma Marfany, Serena Mirra.

  The precise function of CERKL, a Retinitis Pigmentosa (RP) causative gene, is not yet fully understood. There is evidence that CERKL is involved in the regulation of autophagy, stress granules, and mitochondrial metabolism, and it is considered a gene that is resilient against oxidative stress in the retina. Mutations in most RP genes affect photoreceptors, but retinal pigment epithelium (RPE) cells may be also altered. Here, we aimed to analyze the effect of CERKL overexpression and depletion in vivo and in vitro, focusing on the state of the mitochondrial network under oxidative stress conditions. Our work indicates that the depletion of CERKL increases the vulnerability of RPE mitochondria, which show a shorter size and altered shape, particularly upon sodium arsenite treatment. CERKL-depleted cells have dysfunctional mitochondrial respiration particularly upon oxidative stress conditions. The overexpression of two human CERKL isoforms (558 aa and 419 aa), which display different protein domains, shows that a pool of CERKL localizes at mitochondria in RPE cells and that CERKL protects the mitochondrial network-both in size and shape-against oxidative stress. Our results support CERKL being a resilient gene that regulates the mitochondrial network in RPE as in retinal neurons and suggest that RPE cell alteration contributes to particular phenotypic traits in patients carrying CERKL mutations.

Keywords:  CERKL; mitochondrial network; oxidative stress; retinal pigment epithelium; retinitis pigmentosa

DOI:  https://doi.org/10.3390/antiox10122018
J Ocul Pharmacol Ther. 2021 Dec 21.

Mammalian Target of Rapamycin Inhibitor Rapamycin Alleviates 7-Ketocholesterol Induced Inflammatory Responses and Vascular Endothelial Growth Factor Elevation by Regulating MAPK Pathway in Human Retinal Pigment Epithelium Cells.

Lin Yang, Peng Yu, Mei Chen, Bo Lei.

  Purpose: To validate the protective effect of a mammalian target of rapamycin (mTOR) inhibitor on human retinal pigment epithelium (RPE) cells challenged with 7-ketocholesterol (7-KC) and explored the underlying mechanisms. Methods: Human primary RPE (hRPE) cells and ARPE-19 cells were cultured with or without 10 nM of rapamycin for 6 h before being exposed to 10 μM of 7-KC for 24 h. The transcriptome of 7-KC challenged ARPE-19 cells was investigated by RNA sequencing (RNA-seq). The effects of 7-KC and rapamycin on the viability of ARPE-19 cells were measured with CCK-8. Gene expression was verified by real-time PCR, and protein levels were determined by ELISA or Western blotting. Results: The expression of IL-6, IL-8, and vascular endothelial growth factor (VEGF) in RPE cells was markedly increased after stimulation with 7-KC for 12/24 h compared with the controls. RNA-seq showed that a total of 10,243 genes were differentially expressed, with 5,518 genes upregulated and 4,725 genes downregulated between the 7-KC treated and the control group. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that 7-KC stimulation activated mTOR signaling and other pathways, including adherent junction, MAPK, and Wnt signalings. mTOR inhibitor rapamycin significantly suppressed the elevation of IL-6, IL-8, and VEGF stimulated by 7-KC. Rapamycin not only decreased the level of phosphorylated mTOR, P70S6K, 4EBP1 but also inhibited the activation of MAPK pathway. Conclusions: Inhibition of mTOR signaling pathway suppressed the elevation of inflammatory cytokines IL-6, IL-8, and the angiogenic agent VEGF induced by 7-KC. The protective effect of rapamycin was associated with its downregulation on MAPK pathway.

Keywords:  7-KC; MAPK; inflammation; mTOR; rapamycin

DOI:  https://doi.org/10.1089/jop.2021.0082
Biomedicines. 2021 Dec 10. pii: 1871. [Epub ahead of print]9(12):

The Role of Oxidative Stress and Therapeutic Potential of Antioxidants in Graves' Ophthalmopathy.

Tzu-Yu Hou, Shi-Bei Wu, Hui-Chuan Kau, Chieh-Chih Tsai.

  Graves' ophthalmopathy (GO) is the most common extrathyroidal manifestation of Graves' disease. It is characterized initially by an inflammatory process, followed by tissue remodeling and fibrosis, leading to proptosis, exposure keratopathy, ocular motility limitation, and compressive optic neuropathy. The pathogenic mechanism is complex and multifactorial. Accumulating evidence suggests the involvement of oxidative stress in the pathogenesis of GO. Cigarette smoking, a major risk factor for GO, has been shown to induce reactive oxygen species (ROS) generation and oxidative damage in GO orbital fibroblasts. In addition, an elevation in ROS and antioxidant enzymes is observed in tears, blood, and urine, as well as orbital fibroadipose tissues and fibroblasts from GO patients. In vitro and in vivo studies have examined the efficacy of various antioxidant supplements for GO. These findings suggest a therapeutic role of antioxidants in GO patients. This review summarizes the current understanding of oxidative stress in the pathogenesis and potential antioxidants for the treatment of GO.

Keywords:  Graves’ disease; Graves’ ophthalmopathy; antioxidant; immune; oxidative stress; reactive oxygen species

DOI:  https://doi.org/10.3390/biomedicines9121871
Diseases. 2021 Dec 14. pii: 91. [Epub ahead of print]9(4):

Potential Combination Drug Therapy to Prevent Redox Stress and Mitophagy Dysregulation in Retinal Müller Cells under High Glucose Conditions: Implications for Diabetic Retinopathy.

Lalit Pukhrambam Singh, Takhellambam S Devi.

  Chronic hyperglycemia-induced thioredoxin-interacting protein (TXNIP) expression, associated oxidative/nitrosative stress (ROS/RNS), and mitochondrial dysfunction play critical roles in the etiology of diabetic retinopathy (DR). However, there is no effective drug treatment to prevent or slow down the progression of DR. The purpose of this study is to examine if a combination drug treatment targeting TXNIP and the mitochondria-lysosome pathway prevents high glucose-induced mitochondrial stress and mitophagic flux in retinal Müller glial cells in culture, relevant to DR. We show that diabetes induces TXNIP expression, redox stress, and Müller glia activation (gliosis) in rat retinas when compared to non-diabetic rat retinas. Furthermore, high glucose (HG, 25 mM versus low glucose, LG 5.5 mM) also induces TXNIP expression and mitochondrial stress in a rat retinal Müller cell line, rMC1, in in vitro cultures. Additionally, we develop a mitochondria-targeted mCherry and EGFP probe tagged with two tandem COX8a mitochondrial target sequences (adenovirus-CMV-2×mt8a-CG) to examine mitophagic flux in rMC1. A triple drug combination treatment was applied using TXNIP-IN1 (which inhibits TXNIP interaction with thioredoxin), Mito-Tempo (mitochondrial anti-oxidant), and ML-SA1 (lysosome targeted activator of transient calcium channel MCOLN1/TRPML1 and of transcription factor TFEB) to study the mitochondrial-lysosomal axis dysregulation. We found that HG induces TXNIP expression, redox stress, and mitophagic flux in rMC1 versus LG. Treatment with the triple drug combination prevents mitophagic flux and restores transcription factor TFEB and PGC1α nuclear localization under HG, which is critical for lysosome biosynthesis and mitogenesis, respectively. Our results demonstrate that 2×mt8a-CG is a suitable probe for monitoring mitophagic flux, both in live and fixed cells in in vitro experiments, which may also be applicable to in vivo animal studies, and that the triple drug combination treatment has the potential for preventing retinal injury and disease progression in diabetes.

Keywords:  TXNIP; diabetic retinopathy; high glucose; mitophagy; redox stress; retinal Müller cell

DOI:  https://doi.org/10.3390/diseases9040091
Exp Eye Res. 2021 Dec 18. pii: S0014-4835(21)00467-X. [Epub ahead of print] 108901

Omega-3 fatty acids promote neuroprotection, decreased apoptosis and reduced glial cell activation in the retina of a mouse model of OPA1-related autosomal dominant optic atrophy.

Maria Kalogerou, Sotiris Ioannou, Panagiotis Kolovos, Ekatherine Prokopiou, Louiza Potamiti, Kyriacos Kyriacou, Michail Panagiotidis, Maria Ioannou, Eleni Fella, Elena Panayiotou Worth, Tassos Georgiou.

  The purpose of this study was to evaluate the neuroprotective effects of omega-3 polyunsaturated fatty acid (ω3-PUFA) supplementation in a mouse model of OPA1-associated autosomal dominant optic atrophy (ADOA). The blood level of arachidonic acid (AA) and eicosapentaenoic acid (EPA) served to adjust the treatment dosage (AA/EPA = 1.0-1.5). Eight-month-old mice were allocated to four groups (n = 20/group): the ω3-PUFA-treated Opa1enu/+, untreated Opa1enu/+, ω3-PUFA-treated wild-type and untreated wild-type groups. Treated mice received the ω3-PUFAs, EPA and docosahexaenoic acid (DHA; 5:1 ratio) by daily gavage for 4 months based on the measured AA/EPA ratio. Blood, retina and optic nerve (ON) fatty acid levels were determined by gas chromatography, and the retina and ON were histologically examined. Western blotting and/or immunohistochemistry was performed to analyse retinal mediators involved in Opa1-mutation-mediated apoptosis, inflammation and oxidative stress. Increased EPA and reduced AA levels were primarily observed predominantly in the blood and retinal tissues, and a similarly high EPA level tended to be observed in the ONs of ω3-PUFA-treated mice. Retinal ganglion cell and ON axonal densities were higher in both mouse strains upon ω3-PUFA treatment than in the corresponding untreated groups. Caspase-3 expression analysis showed fewer apoptotic retinal cells in both groups of treated mice. Decreases in inflammatory microglia and astrocytes activation and proapoptotic Bcl-2-associated X protein (Bax) expression were noted in the treated groups, with no difference in the antioxidant superoxide dismutase-2 expression. ω3-PUFA supplementation had neuroprotective effects on the retinas of Opa1enu/+ and wild-type mice via blockade of microglia and astrocytes activation and suppression of Bax and caspase-3. Our findings indicated that inhibition of oxidative stress may not be involved in ω3-PUFA-mediated neuroprotection. These novel findings support the use of ω3-PUFAs as a beneficial therapy in the occurrence of ADOA, posing the basis for future clinical trials to confirm these observations.

Keywords:  Autosomal dominant optic atrophy; Neuroprotection; OPA1; Omega-3 polyunsaturated fatty acid

DOI:  https://doi.org/10.1016/j.exer.2021.108901
Free Radic Biol Med. 2021 Dec 16. pii: S0891-5849(21)01112-6. [Epub ahead of print]179 1-10

Hydroxysafflor yellow A and anhydrosafflor yellow B alleviate ferroptosis and parthanatos in PC12 cells injured by OGD/R.

Guangwei Chen, Chang Li, Ling Zhang, Jiehong Yang, Huanhuan Meng, Haitong Wan, Yu He.

  Ferroptosis and parthanatos are two types of programmed cell death associated with cerebral ischemia. There is a sizeable interest in seeking chemical components for the regulation of ferroptosis and parthanatos. Hydroxysafflor yellow A (HSYA) and anhydrosafflor yellow B (AHSYB) mitigated cell death caused by oxidative stress due to antioxidant capacity, yet the mechanism is still uncertain. Thus, we investigated whether HSYA and AHSYB prevent death through these two pathways with the aim to elucidate their potential protective mechanisms of cerebral ischemia. In this study, oxidative stress model was established by treating PC12 cells with oxygen glucose deprivation and reperfusion (OGD/R). Cellular functions and signaling pathways were analyzed in PC12 cells using cell counting kit-8 (CCK-8), flow cytometry, ELISA, iron assay kit, transmission electron microscopy (TEM), immunofluorescence, and western blot analysis. And the research proved HSYA and AHSYB protected cells from oxidative stress. The phenomenon is associated with ferroptosis and parthanatos. HSYA and AHSYB upregulated cystine/glutamate antiporter system xc- (system xc-) and glutathione peroxidase 4 (GPX4), returned the levels of GSH/GSSG ratio, reactive oxygen species (ROS) and iron ion, as well as alleviated lipid peroxidation. By reason of reducing ROS, HSYA and AHSYB restrained poly(ADP-ribose) polymerase-1 (PARP-1) overactivation, reduced the production of excess poly(ADP-ribose) (PAR) polymer and apoptosis inducing factor (AIF) nuclear translocation. The results suggested that HSYA and AHSYB limited ferroptosis and parthanatos to alleviate oxidative stress in PC12 cells. These findings may have implications for improving understanding of how drugs reduce oxidative stress and develop new strategies for treating degenerative diseases such as cerebral ischemia.

Keywords:  Anhydrosafflor yellow B; Ferrroptosis; Hydroxysafflor yellow A; OGD/R; Oxidative stress; PC12 cells; Parthanatos

DOI:  https://doi.org/10.1016/j.freeradbiomed.2021.12.262