| 1. |
- Gáll, Tamás, et al.
(författare)
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Heme induces endoplasmic reticulum stress (Hier stress) in human aortic smooth muscle cells
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9:NOV
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Tidskriftsartikel (refereegranskat)abstract
- Accumulation of damaged or misfolded proteins resulted from oxidative protein modification induces endoplasmic reticulum (ER) stress by activating the pathways of unfolded protein response. In pathologic hemolytic conditions, extracellular free hemoglobin is submitted to rapid oxidation causing heme release. Resident cells of atherosclerotic lesions, after intraplaque hemorrhage, are exposed to heme leading to oxidative injury. Therefore, we raised the question whether heme can also provoke ER stress. Smooth muscle cells are one of the key players of atherogenesis; thus, human aortic smooth muscle cells (HAoSMCs) were selected as a model cell to reveal the possible link between heme and ER stress. Using immunoblotting, quantitative polymerase chain reaction and immunocytochemistry, we quantitated the markers of ER stress. These were: phosphorylated eIF2α, Activating transcription factor-4 (ATF4), DNA-damage-inducible transcript 3 (also known as C/EBP homology protein, termed CHOP), X-box binding protein-1 (XBP1), Activating transcription factor-6 (ATF6), GRP78 (glucose-regulated protein, 78kDa) and heme responsive genes heme oxygenase-1 and ferritin. In addition, immunohistochemistry was performed on human carotid artery specimens from patients who had undergone carotid endarterectomy. We demonstrate that heme increases the phosphorylation of eiF2α in HAoSMCs and the expression of ATF4. Heme also enhances the splicing of XBP1 and the proteolytic cleavage of ATF6. Consequently, there is up-regulation of target genes increasing both mRNA and protein levels of CHOP and GRP78. However, TGFβ and collagen type I decreased. When the heme binding proteins, alpha-1-microglobulin (A1M) and hemopexin (Hpx) are present in cell media, the ER stress provoked by heme is inhibited. ER stress pathways are also retarded by the antioxidant N-acetyl cysteine (NAC) indicating that reactive oxygen species are involved in heme-induced ER stress. Consistent with these findings, elevated expression of the ER stress marker GRP78 and CHOP were observed in smooth muscle cells of complicated lesions with hemorrhage compared to either atheromas or healthy arteries. In conclusion, heme triggers ER stress in a time- and dose-dependent manner in HAoSMCs. A1M and Hpx as well as NAC effectively hamper heme-induced ER stress, supporting their use as a potential therapeutic approach to reverse such a deleterious effects of heme toxicity.
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| 2. |
- Maria, Csidey, et al.
(författare)
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Congenital aniridia patients experience on their visual impairment in Hungary An ANIRIDIA-NET survey
- 2023
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Ingår i: ORVOSI HETILAP. - : AKADEMIAI KIADO ZRT. - 0030-6002. ; 164:34, s. 1342-1349
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Aniridia is a rare congenital panocular disease associated with varying degrees of visual acuity impair-ment. Objective: To assess the experiences of congenital aniridia patients in Hungary, with visual impairment using a ques-tionnaire developed by the ANIRIDIA-NET. Patients and method: Patients completed the Hungarian version of the 20-item ANIRIDIA-NET questionnaire with our assistance. The questionnaire covered demographic data, the most common complaints caused by the disease, the difficulties caused by low vision in different life situations and the frequency of low vision aids used in daily life. Results: 33 subjects (17 female [51.51%] and 16 male [48.48%]), 16 (48.5%) children and 17 (51.5%) adults com-pleted the questionnaire, with an age of 25.69 +/- 17.49 years (5-59 years). Daily photosensitivity was reported by 27 (81.8%), dry eyes by 5 (15.2%), tearing by 4 (12.1%), fluctuating vision by 3 (9.1%), and eye pain by 2 (6.1%) sub-jects. The majority of respondents said that personal communication with schoolmates (16 [48.5%]) or colleagues at work (11 [33.3%]) never caused difficulties because of their visual impairment. 29 people (87.9%) never needed help with daily routines at home, 24 (72.7%) with getting to school/work and 17 (51.5%) with various activities. 29 peo-ple (87.8%) never used low vision aids for communication, 23 (69.7%) for travelling, 20 (60.6%) for participating in social activities, 18 (54.5%) for studying/work. Conclusion: Although aniridia is associated with reduced visual acuity, the majority of people with congenital aniridia, especially in childhood, manage to cope with personal communication and various life situations without difficulty, despite their eye complaints. Low vision aids can be an important aid for them as they grow into adulthood and as they age.
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| 3. |
- Neugart, Susanne, et al.
(författare)
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A synchronized, large-scale field experiment using Arabidopsis thaliana reveals the significance of the UV-B photoreceptor UVR8 under natural conditions
- 2024
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Ingår i: Plant, Cell and Environment. - : Blackwell Publishing. - 0140-7791 .- 1365-3040.
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Tidskriftsartikel (refereegranskat)abstract
- This study determines the functional role of the plant ultraviolet-B radiation (UV-B) photoreceptor, UV RESISTANCE LOCUS 8 (UVR8) under natural conditions using a large-scale 'synchronized-genetic-perturbation-field-experiment'. Laboratory experiments have demonstrated a role for UVR8 in UV-B responses but do not reflect the complexity of outdoor conditions where 'genotype × environment' interactions can mask laboratory-observed responses. Arabidopsis thaliana knockout mutant, uvr8-7, and the corresponding Wassilewskija wild type, were sown outdoors on the same date at 21 locations across Europe, ranging from 39°N to 67°N latitude. Growth and climatic data were monitored until bolting. At the onset of bolting, rosette size, dry weight, and phenolics and glucosinolates were quantified. The uvr8-7 mutant developed a larger rosette and contained less kaempferol glycosides, quercetin glycosides and hydroxycinnamic acid derivatives than the wild type across all locations, demonstrating a role for UVR8 under field conditions. UV effects on rosette size and kaempferol glycoside content were UVR8 dependent, but independent of latitude. In contrast, differences between wild type and uvr8-7 in total quercetin glycosides, and the quercetin-to-kaempferol ratio decreased with increasing latitude, that is, a more variable UV response. Thus, the large-scale synchronized approach applied demonstrates a location-dependent functional role of UVR8 under natural conditions.
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| 4. |
- Pethő, Dávid, et al.
(författare)
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Ferryl hemoglobin and heme induce Α1‐microglobulin in hemorrhaged atherosclerotic lesions with inhibitory function against hemoglobin and lipid oxidation
- 2021
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:13
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Tidskriftsartikel (refereegranskat)abstract
- Infiltration of red blood cells into atheromatous plaques and oxidation of hemoglobin (Hb) and lipoproteins are implicated in the pathogenesis of atherosclerosis. α1‐microglobulin (A1M) is a radical‐scavenging and heme‐binding protein. In this work, we examined the origin and role of A1M in human atherosclerotic lesions. Using immunohistochemistry, we observed a significant A1M immunoreactivity in atheromas and hemorrhaged plaques of carotid arteries in smooth muscle cells (SMCs) and macrophages. The most prominent expression was detected in macrophages of organized hemorrhage. To reveal a possible inducer of A1M expression in ruptured lesions, we exposed aortic endothelial cells (ECs), SMCs and macrophages to heme, Oxy‐ and FerrylHb. Both heme and FerrylHb, but not OxyHb, upregulated A1M mRNA expression in all cell types. Importantly, only FerrylHb induced A1M protein secretion in aortic ECs, SMCs and macrophages. To assess the possible function of A1M in ruptured lesions, we analyzed Hb oxidation and heme‐catalyzed lipid peroxidation in the presence of A1M. We showed that recombinant A1M markedly inhibited Hb oxidation and heme‐driven oxidative modification of low‐density lipoproteins as well plaque lipids derived from atheromas. These results demonstrate the presence of A1M in atherosclerotic plaques and suggest its induction by heme and FerrylHb in the resident cells.
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