scholarly journals High dose expression of heme oxigenase-1 induces retinal degeneration through ER stress-related DDIT3

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Huirong Li ◽  
Bo Liu ◽  
Lili Lian ◽  
Jiajia Zhou ◽  
Shengjin Xiang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Retinal Degeneration ◽  
Knockout Mice ◽  
Photoreceptor Cell ◽  
Heme Oxygenase 1 ◽  
High Dose ◽  
Photoreceptor Degeneration ◽  
Expression Levels ◽  
High Level

Abstract Background Oxidative stress is a common cause of neurodegeneration and plays a central role in retinal degenerative diseases. Heme oxygenase-1 (HMOX1) is a redox-regulated enzyme that is induced in neurodegenerative diseases and acts against oxidative stress but can also promote cell death, a phenomenon that is still unexplained in molecular terms. Here, we test whether HMOX1 has opposing effects during retinal degeneration and investigate the molecular mechanisms behind its pro-apoptotic role. Methods Basal and induced levels of HMOX1 in retinas are examined during light-induced retinal degeneration in mice. Light damage-independent HMOX1 induction at two different expression levels is achieved by intraocular injection of different doses of an adeno-associated virus vector expressing HMOX1. Activation of Müller glial cells, retinal morphology and photoreceptor cell death are examined using hematoxylin-eosin staining, TUNEL assays, immunostaining and retinal function are evaluated with electroretinograms. Downstream gene expression of HMOX1 is analyzed by RNA-seq, qPCR examination and western blotting. The role of one of these genes, the pro-apoptotic DNA damage inducible transcript 3 (Ddit3), is analyzed in a line of knockout mice. Results Light-induced retinal degeneration leads to photoreceptor degeneration and concomitant HMOX1 induction. HMOX1 expression at low levels before light exposure prevents photoreceptor degeneration but expression at high levels directly induces photoreceptor degeneration even without light stress. Photoreceptor degeneration following high level expression of HMOX1 is associated with a mislocalization of rhodopsin in photoreceptors and an increase in the expression of DDIT3. Genetic deletion of Ddit3 in knockout mice prevents photoreceptor cell degeneration normally resulting from high level HMOX1 expression. Conclusion The results reveal that the expression levels determine whether HMOX1 is protective or deleterious in the retina. Furthermore, in contrast to the protective low dose of HMOX1, the deleterious high dose is associated with induction of DDIT3 and endoplasmic reticulum stress as manifested, for instance, in rhodopsin mislocalization. Hence, future applications of HMOX1 or its regulated targets in gene therapy approaches should carefully consider expression levels in order to avoid potentially devastating effects.

scholarly journals Redefining the role of Ca2+-permeable channels in photoreceptor degeneration using diltiazem

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Soumyaparna Das ◽  
Valerie Popp ◽  
Michael Power ◽  
Kathrin Groeneveld ◽  
Jie Yan ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Strong Increase ◽  
Channel Blockers ◽  
Photoreceptor Degeneration ◽  
Therapy Development ◽  
Hypertensive Drug ◽  
Future Therapy

AbstractHereditary degeneration of photoreceptors has been linked to over-activation of Ca2+-permeable channels, excessive Ca2+-influx, and downstream activation of Ca2+-dependent calpain-type proteases. Unfortunately, after more than 20 years of pertinent research, unequivocal evidence proving significant and reproducible photoreceptor protection with Ca2+-channel blockers is still lacking. Here, we show that both D- and L-cis enantiomers of the anti-hypertensive drug diltiazem were very effective at blocking photoreceptor Ca2+-influx, most probably by blocking the pore of Ca2+-permeable channels. Yet, unexpectedly, this block neither reduced the activity of calpain-type proteases, nor did it result in photoreceptor protection. Remarkably, application of the L-cis enantiomer of diltiazem even led to a strong increase in photoreceptor cell death. These findings shed doubt on the previously proposed links between Ca2+ and retinal degeneration and are highly relevant for future therapy development as they may serve to refocus research efforts towards alternative, Ca2+-independent degenerative mechanisms.

scholarly journals Minocycline decreases CCR2-positive monocytes in the retina and ameliorates photoreceptor degeneration in a mouse model of retinitis pigmentosa

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0239108
Author(s):  
Ryo Terauchi ◽  
Hideo Kohno ◽  
Sumiko Watanabe ◽  
Saburo Saito ◽  
Akira Watanabe ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Fluorescent Protein ◽  
Outer Nuclear Layer ◽  
Inhibitory Effect ◽  
Subretinal Space ◽  
Photoreceptor Degeneration ◽  
Retinal Inflammation ◽  
Green Fluorescent

Retinal inflammation accelerates photoreceptor cell death caused by retinal degeneration. Minocycline, a semisynthetic broad-spectrum tetracycline antibiotic, has been previously reported to rescue photoreceptor cell death in retinal degeneration. We examined the effect of minocycline on retinal photoreceptor degeneration using c-mer proto-oncogene tyrosine kinase (Mertk)−/−Cx3cr1GFP/+Ccr2RFP/+ mice, which enabled the observation of CX3CR1-green fluorescent protein (GFP)- and CCR2-red fluorescent protein (RFP)-positive macrophages by fluorescence. Retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed photoreceptor degeneration and accumulation of GFP- and RFP-positive macrophages in the outer retina and subretinal space at 6 weeks of age. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were intraperitoneally administered minocycline. The number of CCR2-RFP positive cells significantly decreased after minocycline treatment. Furthermore, minocycline administration resulted in partial reversal of the thinning of the outer nuclear layer and decreased the number of apoptotic cells, as assessed by the TUNEL assay, in Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In conclusion, we found that minocycline ameliorated photoreceptor cell death in an inherited photoreceptor degeneration model due to Mertk gene deficiency and has an inhibitory effect on CCR2 positive macrophages, which is likely to be a neuroprotective mechanism of minocycline.

scholarly journals Protective Effect of Osmundacetone against Neurological Cell Death Caused by Oxidative Glutamate Toxicity

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 328
Author(s):  
Tuy An Trinh ◽  
Young Hye Seo ◽  
Sungyoul Choi ◽  
Jun Lee ◽  
Ki Sung Kang
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Defense Mechanism ◽  
Neuroprotective Effect ◽  
Glutamate Release ◽  
Chromatin Condensation ◽  
Critical Role ◽  
Glutamate Toxicity ◽  
Heme Oxygenase 1 ◽  
Brain Functions

Oxidative stress is one of the main causes of brain cell death in neurological disorders. The use of natural antioxidants to maintain redox homeostasis contributes to alleviating neurodegeneration. Glutamate is an excitatory neurotransmitter that plays a critical role in many brain functions. However, excessive glutamate release induces excitotoxicity and oxidative stress, leading to programmed cell death. Our study aimed to evaluate the effect of osmundacetone (OAC), isolated from Elsholtzia ciliata (Thunb.) Hylander, against glutamate-induced oxidative toxicity in HT22 hippocampal cells. The effect of OAC treatment on excess reactive oxygen species (ROS), intracellular calcium levels, chromatin condensation, apoptosis, and the expression level of oxidative stress-related proteins was evaluated. OAC showed a neuroprotective effect against glutamate toxicity at a concentration of 2 μM. By diminishing the accumulation of ROS, as well as stimulating the expression of heat shock protein 70 (HSP70) and heme oxygenase-1 (HO-1), OAC triggered the self-defense mechanism in neuronal cells. The anti-apoptotic effect of OAC was demonstrated through its inhibition of chromatin condensation, calcium accumulation, and reduction of apoptotic cells. OAC significantly suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs), including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 kinases. Thus, OAC could be a potential agent for supportive treatment of neurodegenerative diseases.

scholarly journals Heme induces programmed necrosis on macrophages through autocrine TNF and ROS production

Blood ◽  
2012 ◽  
Vol 119 (10) ◽  
pp. 2368-2375 ◽  
Author(s):  
Guilherme B. Fortes ◽  
Leticia S. Alves ◽  
Rosane de Oliveira ◽  
Fabianno F. Dutra ◽  
Danielle Rodrigues ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Critical Role ◽  
Membrane Integrity ◽  
Iron Chelation ◽  
Heme Oxygenase 1 ◽  
Cytotoxic Effects ◽  
Interacting Protein ◽  
Free Heme ◽  
Necrosis Factor

Abstract Diseases that cause hemolysis or myonecrosis lead to the leakage of large amounts of heme proteins. Free heme has proinflammatory and cytotoxic effects. Heme induces TLR4-dependent production of tumor necrosis factor (TNF), whereas heme cytotoxicity has been attributed to its ability to intercalate into cell membranes and cause oxidative stress. We show that heme caused early macrophage death characterized by the loss of plasma membrane integrity and morphologic features resembling necrosis. Heme-induced cell death required TNFR1 and TLR4/MyD88-dependent TNF production. Addition of TNF to Tlr4−/− or to Myd88−/− macrophages restored heme-induced cell death. The use of necrostatin-1, a selective inhibitor of receptor-interacting protein 1 (RIP1, also known as RIPK1), or cells deficient in Rip1 or Rip3 revealed a critical role for RIP proteins in heme-induced cell death. Serum, antioxidants, iron chelation, or inhibition of c-Jun N-terminal kinase (JNK) ameliorated heme-induced oxidative burst and blocked macrophage cell death. Macrophages from heme oxygenase-1 deficient mice (Hmox1−/−) had increased oxidative stress and were more sensitive to heme. Taken together, these results revealed that heme induces macrophage necrosis through 2 synergistic mechanisms: TLR4/Myd88-dependent expression of TNF and TLR4-independent generation of ROS.

Photoreceptor Cell Death Mechanisms in Inherited Retinal Degeneration

2008 ◽  
Vol 38 (3) ◽  
pp. 253-269 ◽  
Author(s):  
Javier Sancho-Pelluz ◽  
Blanca Arango-Gonzalez ◽  
Stefan Kustermann ◽  
Francisco Javier Romero ◽  
Theo van Veen ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Cell Death Mechanisms ◽  
Inherited Retinal Degeneration

Inhibition of LOX-1 prevents inflammation and photoreceptor cell death in retinal degeneration

2020 ◽  
Vol 80 ◽  
pp. 106190
Author(s):  
Xinran Gao ◽  
Ruilin Zhu ◽  
Jiantong Du ◽  
Wenbo Zhang ◽  
Wenna Gao ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Degeneration ◽  
Photoreceptor Cell

scholarly journals AAV-miR-204 Protects from Retinal Degeneration by Attenuation of Microglia Activation and Photoreceptor Cell Death

2020 ◽  
Vol 19 ◽  
pp. 144-156 ◽  
Author(s):  
Marianthi Karali ◽  
Irene Guadagnino ◽  
Elena Marrocco ◽  
Rossella De Cegli ◽  
Annamaria Carissimo ◽  
...  
Keyword(s):  
Cell Death ◽  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Microglia Activation

Apoptosis, retinitis pigmentosa, and degeneration

1994 ◽  
Vol 72 (11-12) ◽  
pp. 489-498 ◽  
Author(s):  
Paul Wong
Keyword(s):  
Cell Death ◽  
Retinitis Pigmentosa ◽  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Retinal Cell ◽  
Current Evidence ◽  
Cell Degeneration ◽  
Genetic Lesion ◽  
Common Causes ◽  
Active Cell Death

The mechanism of photoreceptor cell death in different inherited retinal degenerations is not fully understood. Mutations in a number of different genes (such as rhodopsin, the beta subunit of cGMP phosphodiesterase, and peripherin) have been identified as the primary genetic lesion in different forms of human retinitis pigmentosa, one of the most common causes of inherited blindness. In all cases the manifestation of the disorder regardless of the specific primary genetic lesion is similar, resulting in photoreceptor cell degeneration and blindness. A recent hypothesis is that the active photoreceptor cell death, which is characteristic of these genetically distinct disorders, is mediated by a common induction of apoptosis. In the present review, the current evidence for active cell death during retinal cell death in several different rodent models of retinitis pigmentosa and retinal degeneration is examined.Key words: retinal degeneration, apoptosis, retinitis pigmentosa, clusterin, DNA fragmentation.

scholarly journals Mitochondria-targeted heme oxygenase-1 decreases oxidative stress in renal epithelial cells

2013 ◽  
Vol 305 (3) ◽  
pp. F255-F264 ◽  
Author(s):  
Subhashini Bolisetty ◽  
Amie Traylor ◽  
Abolfazl Zarjou ◽  
Michelle S. Johnson ◽  
Gloria A. Benavides ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Heme Oxygenase ◽  
Manganese Superoxide Dismutase ◽  
Negative Impact ◽  
Tricarboxylic Acid Cycle ◽  
Mitochondrial Fraction ◽  
Hek293 Cells ◽  
Heme Oxygenase 1 ◽  
Protective Mechanism

Mitochondria are both a source and target of the actions of reactive oxygen species and possess a complex system of inter-related antioxidants that control redox signaling and protect against oxidative stress. Interestingly, the antioxidant enzyme heme oxygenase-1 (HO-1) is not present in the mitochondria despite the fact that the organelle is the site of heme synthesis and contains multiple heme proteins. Detoxification of heme is an important protective mechanism since the reaction of heme with hydrogen peroxide generates pro-oxidant ferryl species capable of propagating oxidative stress and ultimately cell death. We therefore hypothesized that a mitochondrially localized HO-1 would be cytoprotective. To test this, we generated a mitochondria-targeted HO-1 cell line by transfecting HEK293 cells with a plasmid construct containing the manganese superoxide dismutase mitochondria leader sequence fused to HO-1 cDNA (Mito-HO-1). Nontargeted HO-1-overexpressing cells were generated by transfecting HO-1 cDNA (HO-1) or empty vector (Vector). Mitochondrial localization of HO-1 with increased HO activity in the mitochondrial fraction of Mito-HO-1 cells was observed, but a significant decrease in the expression of heme-containing proteins occurred in these cells. Both cytosolic HO-1- and Mito-HO-1-expressing cells were protected against hypoxia-dependent cell death and loss of mitochondrial membrane potential, but these effects were more pronounced with Mito-HO-1. Furthermore, decrement in production of tricarboxylic acid cycle intermediates following hypoxia was significantly mitigated in Mito-HO-1 cells. These data suggest that specific mitochondrially targeted HO-1 under acute pathological conditions may have beneficial effects, but the selective advantage of long-term expression is constrained by a negative impact on the synthesis of heme-containing mitochondrial proteins.

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