Overexpression Of Superoxide Dismutase Research Articles

Overexpression of CuZn superoxide dismutase improves high-density lipoprotein function in swine

Cardiovascular disease (CVD) has been the leading cause of death worldwide. As a chronic inflammatory disease, atherosclerosis (AS) acts as the initiating factor for CVD and reactive oxygen species (ROS) play a vital role in its development. Superoxide dismutases (SOD) can alleviate the detrimental effects of ROS and serve as the first line of defense through detoxifying the products derived from oxidative stress in vivo. Considering the potential preventive effects of high-density lipoprotein (HDL) on AS and the close relationship between CuZn superoxide dismutase (CuZnSOD) and HDL, the present work investigated whether CuZnSOD overexpression in swine could improve the function of HDL. Seven CuZnSOD transgenic swine, constructed by sperm and magnetic nanoparticles, demonstrated overexpressed CuZnSOD in the liver (P < 0.01) but comparable level to control in plasma (P > 0.05). CuZnSOD overexpression significantly down-regulated the levels of triglyceride (TG), apolipoprotein A-I (apoA-I) (P < 0.05), and high-density lipoprotein cholesterol (HDL-C) (P < 0.01) in plasma. In the presence of CuZnSOD overexpression, HDL3 significantly inhibited levels of IL-6 and TNF-α induced by oxidized low-density lipoprotein (oxLDL) (P < 0.05), indicating enhanced anti-inflammatory activity of HDL. At the same time, HDL-mediated cholesterol efflux did not decrease (P > 0.05). CuZnSOD overexpression improves the anti-inflammatory function of HDL despite decreased levels of HDL-C. In Conclusion, CuZnSOD overexpression improves HDL function in swine.

Zinc metabolism and its role in immunity status in subjects with trisomy 21: chromosomal dosage effect.

Trisomy 21 (T21), which causes Down syndrome (DS), is the most common chromosomal aneuploidy in humankind and includes different clinical comorbidities, among which the alteration of the immune system has a heavy impact on patient's lives. A molecule with an important role in immune response is zinc and it is known that its concentration is significantly lower in children with T21. Different hypotheses were made about this metabolic alteration and one of the reasons might be the overexpression of superoxide dismutase 1 (SOD1) gene, as zinc is part of the SOD1 active enzymatic center. The aim of our work is to explore if there is a linear correlation between zinc level and immune cell levels measured in a total of 217 blood samples from subjects with T21. Furthermore, transcriptome map analyses were performed using Transcriptome Mapper (TRAM) software to investigate whether a difference in gene expression is detectable between subjects with T21 and euploid control group in tissues and cells involved in the immune response such as lymphoblastoid cells, thymus and white blood cells. Our results have confirmed the literature data stating that the blood zinc level in subjects with T21 is lower compared to the general population; in addition, we report that the T21/control zinc concentration ratio is 2:3, consistent with a chromosomal dosage effect due to the presence of three copies of chromosome 21. The transcriptome map analyses showed an alteration of some gene's expression which might explain low levels of zinc in the blood. Our data suggest that zinc level is not associated with the levels of immunity cells or proteins analyzed themselves and rather the main role of this ion might be played in altering immune cell function.

Overexpression of manganese superoxide dismutase mitigates ACL injury-induced muscle atrophy, weakness and oxidative damage

Oxidative stress has been implicated in the etiology of skeletal muscle weakness following joint injury. We investigated longitudinal patient muscle samples following knee injury (anterior cruciate ligament tear). Following injury, transcriptomic analysis revealed downregulation of mitochondrial metabolism-related gene networks, which were supported by reduced mitochondrial respiratory flux rates. Additionally, enrichment of reactive oxygen species (ROS)-related pathways were upregulated in muscle following knee injury, and further investigation unveiled marked oxidative damage in a progressive manner following injury and surgical reconstruction. We then investigated whether antioxidant protection is effective in preventing muscle atrophy and weakness after knee injury in mice that overexpress Mn-superoxide dismutase (MnSOD+/−). MnSOD+/− mice showed attenuated oxidative damage, atrophy, and muscle weakness compared to wild type littermate controls following ACL transection surgery. Taken together, our results indicate that ROS-related damage is a causative mechanism of muscle dysfunction after knee injury, and that mitochondrial antioxidant protection may hold promise as a therapeutic target to prevent weakness and development of disability.

Dose-Dependent Effect of Mitochondrial Superoxide Dismutase Gene Overexpression on Radioresistance of HEK293T Cells.

Over the last two decades, a multitude of gain-of-function studies have been conducted on genes that encode antioxidative enzymes, including one of the key enzymes, manganese superoxide dismutase (SOD2). The results of such studies are often contradictory, as they strongly depend on many factors, such as the gene overexpression level. In this study, the effect of altering the ectopic expression level of major transcript variants of the SOD2 gene on the radioresistance of HEK293T cells was investigated using CRISPRa technology. A significant increase in cell viability in comparison with the transfection control was detected in cells with moderate SOD2 overexpression after irradiation at 2 Gy, but not at 3 or 5 Gy. A further increase in the level of SOD2 ectopic expression up to 22.5-fold resulted in increased cell viability detectable only after irradiation at 5 Gy. Furthermore, a 15-20-fold increase in SOD2 expression raised the clonogenic survival of cells after irradiation at 5 Gy. Simultaneous overexpression of genes encoding SOD2 and Catalase (CAT) enhanced clonogenic cell survival after irradiation more effectively than separate overexpression of both. In conjunction with the literature data on the suppression of the procarcinogenic effects of superoxide dismutase overexpression by ectopic expression of CAT, the data presented here suggest the potential efficacy of simultaneous overexpression of SOD2 and CAT to reduce oxidative stress occurring in various pathological processes. Moreover, these results illustrate the importance of selecting the degree of SOD2 overexpression to obtain a protective effect.

Improved capacity for the repair of photosystem II via reinforcement of the translational and antioxidation systems in Synechocystis sp. PCC 6803.

In the cyanobacterium Synechocystis sp. PCC 6803, translation factor EF-Tu is inactivated by reactive oxygen species (ROS) via oxidation of Cys82 and the oxidation of EF-Tu enhances the inhibition of the repair of photosystem II (PSII) by suppressing protein synthesis. In our present study, we generated transformants of Synechocystis that overexpressed a mutated form of EF-Tu, designated EF-Tu (C82S), in which Cys82 had been replaced by a Ser residue, and ROS-scavenging enzymes individually or together. Expression of EF-Tu (C82S) alone in Synechocystis enhanced the repair of PSII under strong light, with the resultant mitigation of PSII photoinhibition, but it stimulated the production of ROS. However, overexpression of superoxide dismutase and catalase, together with the expression of EF-Tu (C82S), lowered intracellular levels of ROS and enhanced the repair of PSII more significantly under strong light, via facilitation of the synthesis de novo of the D1 protein. By contrast, the activity of photosystem I was hardly affected in wild-type cells and in all the lines of transformed cells under the same strong-light conditions. Furthermore, transformed cells that overexpressed EF-Tu (C82S), superoxide dismutase, and catalase were able to survive longer under stronger light than wild-type cells. Thus, the reinforced capacity for both protein synthesis and ROS scavenging allowed both photosynthesis and cell proliferation to tolerate strong light.

Superoxide dismutase 2 scavenges ROS to promote osteogenic differentiation of human periodontal ligament stem cells by regulating Smad3 in alveolar bone-defective rats.

Osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) is an essential event in alveolar bone regeneration. Oxidative stress may be the main inhibiting factor of hPDLSC osteogenesis. Superoxide dismutase 2 (SOD2) is a key antioxidant enzyme, but its effect on hPDLSC osteogenic differentiation is unclear. Several surface markers were detected by flow cytometry, and the differentiation potential of hPDLSCs was validated by alkaline phosphatase (ALP), Alizarin Red S, and Oil Red O staining. Osteogenic indicators of hPDLSCs were detected by real-time quantitative polymerase chain reaction (RT-qPCR), Western blotting, and ALP staining. Furthermore, alveolar bone defect rat models were analyzed through micro-CT, hematoxylin and eosin, and Masson staining. The intracellular reactive oxygen species (ROS) level was evaluated by a ROS assay kit. Finally, the expression of SOD2, Smad3, and p-Smad3 in hPDLSCs was detected by RT-qPCR and Western blotting (WB). SOD2 positively regulated the gene and protein expressions of ALP, BMP6, and RUNX2 in hPDLSCs (p<0.05). Ideal bone formation and continuous cortical bone were obtained by transplanting LV-SOD2 hPDLSCs (lentivirus vector for overexpressing SOD2 in hPDLSCs) in vivo. Exogenous H2 O2 downregulated osteogenic indicators (ALP, BMP6, RUNX2) in hPDLSCs (p<0.05); this was reversed by overexpression of SOD2. WB results showed that the Smad3 and p-Smad3 signaling pathways participated in the osteogenic process of SOD2 in hPDLSCs. SOD2 positively regulated hPDLSC osteogenic differentiation in vitro and in vivo. Mechanistically, SOD2 promotes hPDLSC osteogenic differentiation by regulating the phosphorylation of Smad3 to scavenge ROS. This work provides a theoretical basis for the treatment of alveolar bone regeneration.

Targeting the ZNF-148/miR-335/SOD2 signaling cascade triggers oxidative stress-mediated pyroptosis and suppresses breast cancer progression.

The implication of zinc finger protein 148 (ZNF-148) in pathophysiology of most human cancers has been reported; however, the biological functions of ZNF-148 in breast cancer remain unclear. This study sought to elucidate the potential molecular mechanism of ZNF-148 on breast cancer pathology. ZNF148 expression was tested in breast cancer tissues and cells. Then, cells were transfected with ZNF-148 overexpression or downregulation vector, and the cell proliferation, pyroptosis, apoptosis, and reactive oxygen species (ROS) production were analyzed by MTT, western blot, flow cytometry, and immunofluorescence staining, respectively. Tumor-bearing nude mouse was used to evaluate tumorigenesis of ZNF-148. Mechanisms underpinning ZNF-148 were examined using bioinformatics and luciferase assays. We found that ZNF-148 was upregulated in breast cancer tissues and cell lines. Knockdown of ZNF-148 suppressed malignant phenotypes, including cell proliferation, epithelial-mesenchymal transition, and tumorigenesis invitro and invivo, while ZNF-148 overexpression had the opposite effects. Further experiments showed that ZNF-148 deficiency promoted ROS production and triggered both apoptotic and pyroptotic cell death, which were restored by cotreating cells with ROS scavengers. A luciferase reporter assay revealed that miR-335 was the downstream target of ZNF-148 and that overexpressed ZNF-148 increased superoxide dismutase 2 (SOD2) expression by sponging miR-335. In parallel, both miR-335 downregulation and SOD2 overexpression abrogated the antitumor effects of ZNF-148 deficiency on proliferation and pyroptosis in breast cancer cells. Our findings indicated that ZNF-148 promotes breast cancer progression by triggering miR-335/SOD2/ROS-mediated pyroptotic cell death and aid the identification of potential therapeutic targets for breast cancer.

Mitochondrial Genome-Encoded Long Noncoding RNA Cytochrome B and Mitochondrial Dysfunction in Diabetic Retinopathy.

Aims: Mitochondrial dysfunction is closely associated with the development of diabetic complications. In diabetic retinopathy, electron transport chain is compromised and mitochondrial DNA (mtDNA) is damaged, downregulating transcription of mtDNA-encoded cytochrome B (CYTB) and its antisense long noncoding RNA, long noncoding RNA cytochrome B (LncCytB). Our goal was to investigate the role of LncCytB in the regulation of CYTB and mitochondrial function in diabetic retinopathy. Methods: Using human retinal endothelial cells, genetically manipulated for LncCytB (overexpression or silencing), the effect of high glucose (20 mM d-glucose) on LncCytB-CYTB interactions (by chromatin isolation by RNA purification), CYTB gene expression (by real-time quantitative polymerase chain reaction), complex III activity, mitochondrial free radicals, and oxygen consumption rate (OCR, by Seahorse XF analyzer) was investigated. Key results were confirmed in the retinal microvessels from streptozotocin-induced diabetic mice. Results: High glucose decreased LncCytB-CYTB interactions, and while LncCytB overexpression ameliorated glucose-induced decrease in CYTB gene transcripts, complex III activity and OCR and increase in mitochondrial reactive oxygen species, LncCytB-siRNA further attenuated CYTB gene transcription, complex III activity, and OCR. Similar decrease in LncCytB-CYTB interactions and CYTB transcription was observed in diabetic mice. Furthermore, maintenance of mitochondrial homeostasis by overexpressing superoxide dismutase or sirtuin 1 in mice ameliorated diabetes-induced decrease in LncCytB-CYTB interactions and CYTB gene transcripts, and also improved complex III activity and mitochondrial respiration. Innovation and Conclusion: LncCytB downregulation in hyperglycemic milieu downregulates CYTB transcription, which inhibits complex III activity and compromises mitochondrial stability and OCR. Thus, preventing LncCytB downregulation in diabetes has potential of inhibiting the development of diabetic retinopathy, possibly via maintaining mitochondrial respiration. Antioxid. Redox Signal. 39, 817-828.

A mitochondrial pentatricopeptide repeat protein enhances cold tolerance by modulating mitochondrial superoxide in rice

Cold stress affects rice growth and productivity. Defects in the plastid-localized pseudouridine synthase OsPUS1 affect chloroplast ribosome biogenesis, leading to low-temperature albino seedlings and accumulation of reactive oxygen species (ROS). Here, we report an ospus1-1 suppressor, sop10. SOP10 encodes a mitochondria-localized pentatricopeptide repeat protein. Mutations in SOP10 impair intron splicing of the nad4 and nad5 transcripts and decrease RNA editing efficiency of the nad2, nad6, and rps4 transcripts, resulting in deficiencies in mitochondrial complex I, thus decrease ROS generation and rescuing the albino phenotype. Overexpression of different compartment-localized superoxide dismutases (SOD) genes in ospus1-1 reverses the ROS over-accumulation and albino phenotypes to various degrees, with Mn-SOD reversing the best. Mutation of SOP10 in indica rice varieties enhances cold tolerance with lower ROS levels. We find that the mitochondrial superoxide plays a key role in rice cold responses, and identify a mitochondrial superoxide modulating factor, informing efforts to improve rice cold tolerance.

Nimbolide Inhibits SOD2 to Control Pancreatic Ductal Adenocarcinoma Growth and Metastasis.

Reactive oxygen species are frequently associated with various cancers including pancreatic ductal adenocarcinomas (PDACs). Superoxide dismutase 2 (SOD2) is an enzyme that plays an important role in reactive oxygen species (ROS) signaling. Investigating the molecular function and biological functions of SOD2 can help us develop new therapeutic options and uncover new biomarkers for PDAC diagnosis and prognosis. Here, we show that nimbolide (NB), a triterpene limonoid, effectively blocks the growth and metastasis of PDACs by suppressing the expression and activity of SOD2. To identify the role of SOD2 in NB-induced anticancer activity, we used RNA interference to silence and plasmid transfection to overexpress it. Silencing SOD2 significantly reduced the growth and metastatic characteristics like epithelial-to-mesenchymal transition, invasion, migration, and colony-forming capabilities of PDACs, and NB treatment further reduced these characteristics. Conversely, the overexpression of SOD2 enhanced these metastatic characteristics. ROS signaling has a strong feedback mechanism with the PI3K/Akt signaling pathway, which could be mediated through SOD2. Finally, NB treatment to SOD2-overexpressing PDAC xenografts resulted in significant inhibition of tumor growth and metastasis. Overall, this work suggests that NB, a natural and safe phytochemical that silences SOD2 to induce high levels of ROS generation, results in increased apoptosis and reduced growth and progression of PDACs. The role of SOD2 in regulating NB-induced ROS generation presents itself as a therapeutic option for PDACs.

Targeting SOD1 via RNAi with PEGylated graphene oxide nanoparticles in platinum-resistant ovarian cancer

Acquired platinum resistance poses a significant therapeutic impediment to ovarian cancer patient care, accounting for more than 200,000 deaths annually worldwide. We previously identified that overexpression of the antioxidant superoxide dismutase 1 (SOD1) in ovarian cancer is associated with a platinum-resistant phenotype via conferring oxidative stress resistance against platinum compounds. We further demonstrated that enzymatic inhibition using small-molecule inhibitors or silencing of SOD1 via RNA interference (RNAi) increased cisplatin sensitivity and potency in vitro. We launched this study to explore the potential therapeutic applications of SOD1 silencing in vivo in order to reverse cisplatin resistance using a graphene-based siRNA delivery platform. PEGylated graphene oxide (GO) polyethyleneimine (GOPEI-mPEG) nanoparticle was complexed with SOD1 siRNA. GOPEI-mPEG-siSOD1 exhibited high biocompatibility, siRNA loading capacity, and serum stability, and showed potent downregulation of SOD1 mRNA and protein levels. We further observed that cisplatin and PEI elicited mitochondrial dysfunction and transcriptionally activated the mitochondrial unfolded protein response (UPRmt) used as a reporter for their respective cytotoxicities. SOD1 silencing was found to augment cisplatin-induced cytotoxicity resulting in considerable tumour growth inhibition in cisplatin-sensitive A2780 and cisplatin-resistant A2780DDP subcutaneous mouse xenografts. Our study highlights the potential therapeutic applicability of RNAi-mediated targeting of SOD1 as a chemosensitizer for platinum-resistant ovarian cancers.

Fine particulate matter (PM2.5)-induced pulmonary oxidative stress contributes to increases in glucose intolerance and insulin resistance in a mouse model of circadian dyssynchrony

Results of human and animal studies independently suggest that either ambient fine particulate matter (PM2.5) air pollution exposure or a disturbed circadian rhythm (circadian dyssynchrony) are important contributing factors to the rapidly evolving type-2-diabetes (T2D) epidemic. The objective of this study is to investigate whether circadian dyssynchrony increases the susceptibility to PM2.5 and how PM2.5 affects metabolic health in circadian dyssynchrony. We examined systemic and organ-specific changes in glucose homeostasis and insulin sensitivity in mice maintained on a regular (12/12 h light/dark) or disrupted (18/6 h light/dark, light-induced circadian dyssynchrony, LICD) light cycle exposed to air or concentrated PM2.5 (CAP, 6 h/day, 30 days). Exposures during Zeitgeber ZT3–9 or ZT11–17 (Zeitgeber in circadian time, ZT0 = begin of light cycle) tested for time-of-day PM2.5 sensitivity (chronotoxicity). Mice transgenic for lung-specific overexpression of extracellular superoxide dismutase (ecSOD-Tg) were used to assess the contribution of CAP-induced pulmonary oxidative stress. Both, CAP exposure from ZT3–9 or ZT11–17, decreased glucose tolerance and insulin sensitivity in male mice with LICD, but not in female mice or in mice kept on a regular light cycle. Although changes in glucose homeostasis in CAP-exposed male mice with LICD were not associated with obesity, they were accompanied by white adipose tissue (WAT) inflammation, impaired insulin signaling in skeletal muscle and liver, and systemic and pulmonary oxidative stress. Preventing CAP-induced oxidative stress in the lungs mitigated the CAP-induced decrease in glucose tolerance and insulin sensitivity in LICD. Our results demonstrate that circadian dyssynchrony is a novel susceptibility state for PM2.5 and suggest that PM2.5 by inducing pulmonary oxidative stress increases glucose intolerance and insulin resistance in circadian dyssynchrony.

SOD2 in platelets: with age comes responsibility

Aging can be described as a complex progressive biological process that leads to physical and mental deterioration and eventually death [[1]Partridge L. Deelen J. Slagboom P.E. Facing up to the global challenges of ageing.Nature. 2018; 561: 45-56Crossref PubMed Scopus (438) Google Scholar]. It represents the accumulation of cellular and molecular alterations from environmental insults, genetics predispositions, and epigenetic responses [[2]Fearon I.M. Risk factors, oxidative stress, and cardiovascular disease.in: Laher I. Systems Biology of Free Radicals and Antioxidants. Springer Berlin Heidelberg, Berlin, Heidelberg2014: 765-790Crossref Scopus (2) Google Scholar] that occur over time. Cumulatively, these enhance the risk of a broad range of diseases, including thrombotic diseases, such as stroke, myocardial infarction, and venous thromboembolism [[3]Engbers M.J. van Hylckama Vlieg A. Rosendaal F.R. Venous thrombosis in the elderly: incidence, risk factors and risk groups.J Thromb Haemost. 2010; 8: 2105-2112Abstract Full Text Full Text PDF PubMed Scopus (196) Google Scholar,[4]Tsao C.W. Aday A.W. Almarzooq Z.I. Alonso A. Beaton A.Z. Bittencourt M.S. Boehme A.K. Buxton A.E. Carson A.P. Commodore-Mensah Y. Elkind M.S.V. Evenson K.R. Eze-Nliam C. Ferguson J.F. Generoso G. Ho J.E. Kalani R. Khan S.S. Kissela B.M. Knutson K.L. et al.Heart disease and stroke statistics-2022 update: a report from the American Heart Association.Circulation. 2022; 145: e153-e639Crossref PubMed Scopus (750) Google Scholar]. Although several vascular cell types (eg, endothelial cells) and plasma factors (eg, coagulation factors) are known to contribute to thrombosis, platelet activation forms a key step in both initiation and growth of thrombus in adverse clinical events [[5]Stark K. Massberg S. 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Superoxide production and reducing activity in human platelets.J Clin Invest. 1977; 59: 149-158Crossref PubMed Scopus (136) Google Scholar], a highly reactive species with a relatively short half-life, that can alter platelet function and activity [[18]Handin R.I. Karabin R. Boxer G.J. Enhancement of platelet function by superoxide anion.J Clin Invest. 1977; 59: 959-965Crossref PubMed Scopus (146) Google Scholar]. Given the damaging nature of ROS, cells have several mechanisms to counteract oxidative stress by producing antioxidants. The conversion of O2•− to H2O2 is catalyzed by superoxide dismutase (SOD). Subsequent detoxification of H2O2 to H2O, performed by other enzymes, such as glutathione peroxidase and catalase, forms a robust antioxidant system to reduce oxidative stress and prevent cellular damage in aerobic organisms. In mammals, 3 major SOD isoforms exist that differ in their cellular localization and metal cofactors in the catalytic site [[19]Wang Y. Branicky R. Noe A. Hekimi S. Superoxide dismutases: dual roles in controlling ROS damage and regulating ROS signaling.J Cell Biol. 2018; 217: 1915-1928Crossref PubMed Scopus (711) Google Scholar]. These include copper-zinc SOD (SOD1), manganese SOD (SOD2), and extracellular SOD (SOD3). SOD2 is the major isoform in mitochondria, a notable source of ROS generation because of uncoupling and premature escape of electrons from the electron transport chain. Despite not having a nucleus, platelets are metabolically active and contain abundant mitochondria [[20]Melchinger H. Jain K. Tyagi T. Hwa J. Role of platelet mitochondria: life in a nucleus-free zone.Front Cardiovasc Med. 2019; 6: 153Crossref PubMed Scopus (81) Google Scholar]. Maintenance of mitochondrial integrity is crucial to platelet function, and disruption of the mitochondrial membrane potential can lead to altered platelet activity and platelet apoptosis [21Lopez J.J. Salido G.M. Gomez-Arteta E. Rosado J.A. Pariente J.A. 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Tyagi T. Du J. Hu X. Patell K. Martin K.A. Hwa J. Unfolded protein response differentially modulates the platelet phenotype.Circ Res. 2022; 131: 290-307Crossref PubMed Scopus (1) Google Scholar]. Aging is associated with elevated ROS production and subsequently a higher propensity for mitochondrial dysfunction [[27]Cui H. Kong Y. Zhang H. Oxidative stress, mitochondrial dysfunction, and aging.J Signal Transduct. 2012; 2012646354Crossref PubMed Google Scholar]. Physiological antioxidant mechanisms, including SODs are in place to counteract this age-associated increase in oxidative stress. Interestingly, SOD2 is the only SOD which has been shown to be essential for survival; mice lacking SOD2 do not survive and die shortly after birth as a result of dilated cardiomyopathy and neurodegeneration [[28]Li Y. Huang T.T. Carlson E.J. Melov S. Ursell P.C. Olson J.L. Noble L.J. Yoshimura M.P. Berger C. Chan P.H. Wallace D.C. Epstein C.J. Dilated cardiomyopathy and neonatal lethality in mutant mice lacking manganese superoxide dismutase.Nat Genet. 1995; 11: 376-381Crossref PubMed Scopus (1453) Google Scholar,[29]Lebovitz R.M. Zhang H. Vogel H. Cartwright Jr., J. Dionne L. Lu N. Huang S. Matzuk M.M. Neurodegeneration, myocardial injury, and perinatal death in mitochondrial superoxide dismutase-deficient mice.Proc Natl Acad Sci U S A. 1996; 93: 9782-9787Crossref PubMed Scopus (838) Google Scholar]. Earlier studies have shown that lifelong SOD2 deficiency in aging mice results in higher atherosclerotic plaque formation, leading to increased vascular and cardiac dysfunction [[30]Vendrov A.E. Stevenson M.D. Alahari S. Pan H. Wickline S.A. Madamanchi N.R. Runge M.S. Attenuated superoxide dismutase 2 activity induces atherosclerotic plaque instability during aging in hyperlipidemic mice.J Am Heart Assoc. 2017; 6Crossref PubMed Scopus (35) Google Scholar,[31]Van Remmen H. Williams M.D. Guo Z. Estlack L. Yang H. Carlson E.J. Epstein C.J. Huang T.T. Richardson A. Knockout mice heterozygous for Sod2 show alterations in cardiac mitochondrial function and apoptosis.Am J Physiol Heart Circ Physiol. 2001; 281: H1422-H1432Crossref PubMed Google Scholar]. Of note, these studies used heterozygous SOD2 knockout mice with 16-month-old mice categorized as middle-aged mice, equivalent to the 40- to 59-year age group in humans. Previous reports suggest that although deletion of SOD2 is deleterious to cells, its overexpression does not increase lifespan [[32]Jang Y.C. Perez V.I. Song W. Lustgarten M.S. Salmon A.B. Mele J. Qi W. Liu Y. Liang H. Chaudhuri A. Ikeno Y. Epstein C.J. Van Remmen H. Richardson A. Overexpression of Mn superoxide dismutase does not increase life span in mice.J Gerontol A Biol Sci Med Sci. 2009; 64: 1114-1125Crossref PubMed Scopus (152) Google Scholar]. The recent exciting study by Sonkar et al. [[33]Sonkar V.K. Eustes A.S. Ahmed A. Jensen M. Solanki M.V. Swamy J. Kumar R. Fidler T.P. Houtman J.C.D. Allen B.G. Spitz D.R. Abel E.D. Dayal S. Endogenous SOD2 (superoxide dismutase) regulates platelet-dependent thrombin generation and thrombosis during aging.Arterioscler Thromb Vasc Biol. 2023; 43: 79-91Crossref PubMed Scopus (3) Google Scholar] published in Arteriosclerosis, Thrombosis, and Vascular Biology provides further mechanistic insights into the crucial role of the SOD2 (MnSOD) in platelets with aging (summarized in Figure 1). Using young (4-5 months) and aged (18-20 months) wild-type and platelet-specific SOD2 knockout mice, the authors demonstrated that although the platelet SOD2 deletion in mice does not affect platelet aggregation and adhesion, SOD2 serves as a major regulator of mitochondrial function, ROS accumulation calcium regulation, thrombin generation, and arterial thrombosis during aging. The role of platelet SOD2 clearly becomes more relevant with age as an earlier study by Fidler et al. [[34]Fidler T.P. Rowley J.W. Araujo C. Boudreau L.H. Marti A. Souvenir R. Dale K. Boilard E. Weyrich A.S. Abel E.D. Superoxide dismutase 2 is dispensable for platelet function.Thromb Haemost. 2017; 117: 1859-1867Crossref PubMed Scopus (16) Google Scholar] demonstrated no change in mitochondrial potential and platelet hyperactivation in young SOD2 knockout mice. Interestingly, mice heterozygous for SOD2 displayed no compensatory changes in SOD1, catalase, or glutathione peroxidases, further emphasizing the important role of mitochondrial SOD2 [[35]Van Remmen H. Salvador C. Yang H. Huang T.T. Epstein C.J. Richardson A. Characterization of the antioxidant status of the heterozygous manganese superoxide dismutase knockout mouse.Arch Biochem Biophys. 1999; 363: 91-97Crossref PubMed Scopus (141) Google Scholar]. Over the past few decades, identification of genetic polymorphisms, especially those associated with protein encoding genes, has opened new avenues in understanding the pathogenesis of human diseases and the nature of phenotypic diversity. Single-nucleotide polymorphisms of the human MnSOD gene have been observed in both the sequences coding for the mature protein and the sequences required for mitochondrial targeting [36Sutton A. Khoury H. Prip-Buus C. Cepanec C. Pessayre D. Degoul F. The Ala16Val genetic dimorphism modulates the import of human manganese superoxide dismutase into rat liver mitochondria.Pharmacogenetics. 2003; 13: 145-157Crossref PubMed Scopus (360) Google Scholar, 37Xu Y. Fang F. Dhar S.K. St Clair W.H. Kasarskis E.J. St Clair D.K. The role of a single-stranded nucleotide loop in transcriptional regulation of the human sod2 gene.J Biol Chem. 2007; 282: 15981-15994Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar, 38Bonetta Valentino R. The structure-function relationships and physiological roles of MnSOD mutants.Biosci Rep. 2022; : 42Google Scholar]. Polymorphisms in the human SOD2 gene have been linked to a higher risk of type 2 diabetes [39Nomiyama T. Tanaka Y. Piao L. Nagasaka K. Sakai K. Ogihara T. Nakajima K. Watada H. Kawamori R. The polymorphism of manganese superoxide dismutase is associated with diabetic nephropathy in Japanese type 2 diabetic patients.J Hum Genet. 2003; 48: 138-141Crossref PubMed Scopus (96) Google Scholar, 40Lee S.J. Choi M.G. Kim D.S. Kim T.W. Manganese superoxide dismutase gene polymorphism (V16A) is associated with stages of albuminuria in Korean type 2 diabetic patients.Metabolism. 2006; 55: 1-7Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar, 41Vats P. Sagar N. Singh T.P. Banerjee M. Association of Superoxide dismutases (SOD1 and SOD2) and Glutathione peroxidase 1 (GPx1) gene polymorphisms with type 2 diabetes mellitus.Free Radic Res. 2015; 49: 17-24Crossref PubMed Scopus (48) Google Scholar], coronary artery disease [[42]Souiden Y. Mallouli H. Meskhi S. Chaabouni Y. Rebai A. Cheour F. Mahdouani K. MnSOD and GPx1 polymorphism relationship with coronary heart disease risk and severity.Biol Res. 2016; 49: 22Crossref PubMed Scopus (34) Google Scholar], and cardiomyopathy [[43]Hiroi S. Harada H. Nishi H. Satoh M. Nagai R. Kimura A. Polymorphisms in the SOD2 and HLA-DRB1 genes are associated with nonfamilial idiopathic dilated cardiomyopathy in Japanese.Biochem Biophys Res Commun. 1999; 261: 332-339Crossref PubMed Scopus (167) Google Scholar]. Prevalence of these diseases increases substantially with age, and these diseases have also been closely linked to platelet hyperactivation and thrombosis [[44]Le Blanc J. Lordkipanidze M. Platelet function in aging.Front Cardiovasc Med. 2019; 6: 109Crossref PubMed Scopus (42) Google Scholar]. Previous studies show that missense mutations in SOD2 are especially prevalent in populations with African ancestry and are associated with a higher risk of vascular complications and age-mediated CVDs [[45]Stessman J. Maaravi Y. Hammerman-Rozenberg R. Cohen A. Nemanov L. Gritsenko I. Gruberman N. Ebstein R.P. Candidate genes associated with ageing and life expectancy in the Jerusalem longitudinal study.Mech Ageing Dev. 2005; 126: 333-339Crossref PubMed Scopus (43) Google Scholar]. As highlighted by Sonkar et al., [[33]Sonkar V.K. Eustes A.S. Ahmed A. Jensen M. Solanki M.V. Swamy J. Kumar R. Fidler T.P. Houtman J.C.D. Allen B.G. Spitz D.R. Abel E.D. Dayal S. Endogenous SOD2 (superoxide dismutase) regulates platelet-dependent thrombin generation and thrombosis during aging.Arterioscler Thromb Vasc Biol. 2023; 43: 79-91Crossref PubMed Scopus (3) Google Scholar] their results are relevant in understanding the cardiovascular consequences of decreased SOD2 function in diverse populations (Summarized in Figure 2). Endogenous oxidative stress has long been known as a major determinant of aging [[46]Melov S. Ravenscroft J. Malik S. Gill M.S. Walker D.W. Clayton P.E. Wallace D.C. Malfroy B. Doctrow S.R. Lithgow G.J. Extension of life-span with superoxide dismutase/catalase mimetics.Science. 2000; 289: 1567-1569Crossref PubMed Scopus (774) Google Scholar,[47]Keaney M. Gems D. No increase in lifespan in Caenorhabditis elegans upon treatment with the superoxide dismutase mimetic EUK-8.Free Radic Biol Med. 2003; 34: 277-282Crossref PubMed Scopus (91) Google Scholar]. Several antioxidant nutrient supplements and mimetics have been considered for their therapeutic value in human diseases, including cancers and cardiovascular dysfunction [[48]Forman H.J. Zhang H. Targeting oxidative stress in disease: promise and limitations of antioxidant therapy.Nat Rev Drug Discov. 2021; 20: 689-709Crossref PubMed Scopus (396) Google Scholar,[49]Martemucci G. Portincasa P. Di Ciaula A. Mariano M. Centonze V. D'Alessandro A.G. Oxidative stress, aging, antioxidant supplementation and their impact on human health: an overview.Mech Ageing Dev. 2022; 206111707Crossref PubMed Scopus (7) Google Scholar]. Use of native SODs as therapeutics has shown limited promise, partly due to their larger molecular size (resulting in lower cell permeability), along with a limited circulating half-life [[46]Melov S. Ravenscroft J. Malik S. Gill M.S. Walker D.W. Clayton P.E. Wallace D.C. Malfroy B. Doctrow S.R. Lithgow G.J. Extension of life-span with superoxide dismutase/catalase mimetics.Science. 2000; 289: 1567-1569Crossref PubMed Scopus (774) Google Scholar]. By contrast, smaller compounds, such as the cyclic polyamine SOD mimetic GC4419, can overcome these limitations. Along with longer half-lives, these SOD mimetics provide a better access to cells, prevent immunogenic responses, and may be more cost effective [[50]Batinic-Haberle I. Reboucas J.S. Spasojevic I. Superoxide dismutase mimics: chemistry, pharmacology, and therapeutic potential.Antioxid Redox Signal. 2010; 13: 877-918Crossref PubMed Scopus (397) Google Scholar]. Sonkar et al. [[33]Sonkar V.K. Eustes A.S. Ahmed A. Jensen M. Solanki M.V. Swamy J. Kumar R. Fidler T.P. Houtman J.C.D. Allen B.G. Spitz D.R. Abel E.D. Dayal S. Endogenous SOD2 (superoxide dismutase) regulates platelet-dependent thrombin generation and thrombosis during aging.Arterioscler Thromb Vasc Biol. 2023; 43: 79-91Crossref PubMed Scopus (3) Google Scholar] report that GC4419 considerably reduced the formation of procoagulant platelets and the thrombotic susceptibility in aged SOD2 KO and wild-type mice. Despite the lack of human data in their study, the authors suggest that the drug could be potentially useful in prevention of thrombotic complications in the aged population. GC4419, developed by Galera Therapeutics, is one of the many potential SOD mimetics that are being explored for their potential in limiting the oxidative stress associated with pathophysiologic conditions [[51]Heer C.D. Davis A.B. Riffe D.B. Wagner B.A. Falls K.C. Allen B.G. Buettner G.R. Beardsley R.A. Riley D.P. Spitz D.R. Superoxide dismutase mimetic GC4419 enhances the oxidation of pharmacological ascorbate and its anticancer effects in an H2O2-dependent manner.Antioxidants (Basel). 2018; 7: 18Crossref PubMed Scopus (29) Google Scholar]. It has already completed phase 1/2a clinical trials for use in chemotherapy and radiation treatment for squamous cell cancer and is currently in phase 2b clinical trials [[52]Sishc B.J. Ding L. Nam T.K. Heer C.D. Rodman S.N. Schoenfeld J.D. Fath M.A. Saha D. Pulliam C.F. Langen B. Beardsley R.A. Riley D.P. Keene J.L. Spitz D.R. Story M.D. Avasopasem manganese synergizes with hypofractionated radiation to ablate tumors through the generation of hydrogen peroxide.Sci Transl Med. 2021; : 13Google Scholar]. Regarding antioxidant therapeutic strategies, the results from preclinical and clinical trials are conflicting [[53]Madamanchi N.R. Hakim Z.S. Runge M.S. Oxidative stress in atherogenesis and arterial thrombosis: the disconnect between cellular studies and clinical outcomes.J Thromb Haemost. 2005; 3: 254-267Abstract Full Text Full Text PDF PubMed Scopus (156) Google Scholar]. Although the antioxidant mimetics are successful in ameliorating oxidative stress markers in mouse models and in vitro studies [[46]Melov S. Ravenscroft J. Malik S. Gill M.S. Walker D.W. Clayton P.E. Wallace D.C. Malfroy B. Doctrow S.R. Lithgow G.J. Extension of life-span with superoxide dismutase/catalase mimetics.Science. 2000; 289: 1567-1569Crossref PubMed Scopus (774) Google Scholar], their effect on limiting the disease progression is mostly negligible. Several randomized clinical trials using antioxidant supplements and/or mimetics have been disappointing. The potential reasons for failure remain complex and still poorly understood. This can be primarily attributed to the fact that although oxidative stress is a characteristic feature of several human diseases, including CVD, it does not necessarily form the major cause of the disease and may be a consequence of the disease. Moreover, diverse ROS species may be formed in different stages or etiologies of disease pathologies, and thus, a single antioxidant agent may not be sufficient for potential therapeutic benefit. Several ROS including O2•− and H2O2 play a role in physiological signaling, and thus, excessive scavenging of these signaling molecules can be detrimental. To add to the “antioxidant paradox,” it is likely that healthy subjects likely already have sufficient antioxidants and thus would exhibit a limited potential beneficial effect of supplemental antioxidant agents [[54]Halliwell B. The antioxidant paradox: less paradoxical now?.Br J Clin Pharmacol. 2013; 75: 637-644Crossref PubMed Scopus (226) Google Scholar]. With many of the SOD mimetics, such as GC4419, factors such as, pharmacokinetics (bioavailability), pharmacodynamics (culprit ROS species), route, and the timing of administration as per the disease pathology have not been clearly established despite some success in early phase clinical trials. With several SOD mimetics under consideration, dosing and the respective patient populations, need to be considered and duly compared while selecting one mimetic (or antioxidant enzyme) over the other. Despite all the strengths and limitations of clinical trials and research, it is clear that oxidative stress plays a pivotal role in the pathogenesis of CVD and hemostasis, and limiting oxidative stress is beneficial. Thus, antioxidant supplementation and use of antioxidant mimetics, such as SOD mimetics, does offer promise in diverse aging-related pathologies. However, there is an emerging need for careful evaluation of the use of these therapeutic agents for tailoring benefits in health and disease. Consideration should be given to the use of multiple antioxidants that may work in tandem to limit the differential effects of the reactive oxidants. Moreover, the choice of antioxidants, dose, and duration needs to be meticulously assessed. As is now evident, the indiscriminate use of antioxidants may not be favorable; instead, the antioxidant supplementation would only be likely beneficial when given to the right subject at the right time and for the right duration. Indeed, studies should include both human and mouse disease models to evaluate the potential value of new and existing antioxidants. Uniform guidelines about appropriate animal models and how these correspond to human aging and disease progression would be important for future studies that build on the present study by Sonkar et al. [[33]Sonkar V.K. Eustes A.S. Ahmed A. Jensen M. Solanki M.V. Swamy J. Kumar R. Fidler T.P. Houtman J.C.D. Allen B.G. Spitz D.R. Abel E.D. Dayal S. Endogenous SOD2 (superoxide dismutase) regulates platelet-dependent thrombin generation and thrombosis during aging.Arterioscler Thromb Vasc Biol. 2023; 43: 79-91Crossref PubMed Scopus (3) Google Scholar]. More exhaustive pharmacokinetics and toxicology studies need to be conducted for a conclusive consensus on the clinical needs and usage. The study by Sonkar et al. [[33]Sonkar V.K. Eustes A.S. Ahmed A. Jensen M. Solanki M.V. Swamy J. Kumar R. Fidler T.P. Houtman J.C.D. Allen B.G. Spitz D.R. Abel E.D. Dayal S. Endogenous SOD2 (superoxide dismutase) regulates platelet-dependent thrombin generation and thrombosis during aging.Arterioscler Thromb Vasc Biol. 2023; 43: 79-91Crossref PubMed Scopus (3) Google Scholar] highlights the importance of SOD2 in platelet mitochondrial function and thrombosis in aging, providing new directions in the development of antioxidant therapeutic strategies. The authors are supported by National Institutes of HealthNational Institutes of Health National Heart, Lung, and Blood Institute grants R01HL115247, R01HL122815, and R01HL150515 and T32HL007974 (to S.G.). K.J., S.G., and J.H. developed and wrote the manuscript. All authors read and approved the final paper. The authors declare no conflict of interest.

Tetrandrine Inhibits Cancer Stem Cell Characteristics and Epithelial to Mesenchymal Transition in Triple-Negative Breast Cancer via SOD1/ROS Signaling Pathway.

Targeting the stemness of triple-negativebreastcancer (TNBC)is a potential therapeutic approach for treating TNBC.Tetrandrine, a natural plant alkaloid, has several anticancer effects. Here, we aimed to evaluate the efficacy of tetrandrine in cancer stemness and epithelial to mesenchymal transition (EMT) in TNBC, and to explore the underlying mechanisms. The effects of tetrandrine on cell growth, cell viability, cell stemness capacity, cell migration, and cell invasion, as well as the molecules involved in these processes, were investigated in a cell culture system. An in vivo xenograft tumor and lung metastasis study was performed using nude mice to verify the effects and mechanisms of tetrandrine. Tetrandrine exhibited antiproliferative and cell cycle arrest activities in TNBC cell lines, significantly reduced aldehyde dehydrogenase and CD44[Formula: see text]CD24[Formula: see text] characteristic subpopulation, and successfully prevented mammosphere formation. It suppressed migration and invasion, enhanced anoikis, and regulated the expression of proteins involved in the EMT, including E-cadherin, Vimentin, and Occludin, in both TNBC cells and MDA-MB-231 spheroid cells. Further studies revealed that tetrandrine downregulated the expression of superoxide dismutase 1 (SOD1) and catalase and induced reactive oxygen species (ROS) production, which subsequently contributed to the inhibition of cell EMT and stemness. The in vivo studies also showed that tetrandrine inhibited tumor growth and metastasis of both adherent normal cells, and flow cytometry sorted specific CD44[Formula: see text]CD24[Formula: see text] breast cancer stem cells, which could be rescued by SOD1 overexpression. The results of this study suggest that tetrandrine could effectively inhibit breast cancer stem cell characteristics and the EMT process via the SOD1/ROS signaling pathway. Therefore, tetrandrine can be considered a promising anti-TNBC agent.

Overexpression of Iron Super Oxide Dismutases A/B Genes Are Associated with Antimony Resistance of Leishmania tropica Clinical Isolates.

Pentavalent antimonial has been a drug of choice against leishmaniasis, despite the emergence of treatment failure. Identification of resistance markers is urgently needed to design new therapeutic strategies. Iron-Superoxide dismutases (Fe-SODs) are antioxidant enzymes contributing to detoxify reactive oxygen species to prevent a cell from oxidative stress. Since antimonial compounds induce oxidative stress, in this survey, the expression of SOD genes was investigated to identify their expression pattern in clinical resistant isolates. This cross-sectional survey was done in Mashhad City, northeast of Iran during 2014 to 2019. The RNA expression level of mitochondrial (SODA) and glycosomal (SODB) superoxide dismutase was investigated in 25 antimony responsive (n=15) and unresponsive (n=10) anthroponotic cutaneous leishmaniasis (ACL) patients. Total RNA extraction and cDNA synthesis, the qRT-PCR approach was utilized to investigate the relative RNA expression level. The transcript level of SODs was over-expressed in the most resistant isolates. Gene expression analysis demonstrated the over-expression of SODA and B by a factor of 3.8 and 4.81, respectively, in resistance isolates vs. sensitive ones. Aberrant expression of SODA/B in unresponsive parasites could potentially implicate in detoxifying antimony-induced oxidative stress. Moreover, SODs might be considered as potential predictive markers of the response to antimonials in ACL patients in endemic areas.

Transcription factor Nrf2 binds to circRNAPIBF1 to regulate SOD2 in lung adenocarcinoma progression.

Emerging evidence indicates that circular RNAs (circRNAs) play important roles in disease development, especially in cancers. Analysis of circRNA expression microarrays from the Gene Expression Omnibus database revealed that circPIBF1 was highly upregulated in lung adenocarcinoma (LUAD). The main aim of this study was to probe the function of circPIBF1 in pyroptosis of LUAD cells and the signal transduction pathways involved. CircPIBF1 was significantly overexpressed in LUAD and was related to the dismal prognosis of patients with LUAD. CircPIBF1 could bind to nuclear factor erythroid 2-related factor 2 (Nrf2), which further promoted the expression of superoxide dismutase 2 (SOD2). In addition, Nrf2 was also observed to recruit histone acetyltransferase E1A binding protein p300 (EP300) to enhance H3K27ac modification of SOD2, thus modulating the Nrf2-Keap1 signaling pathway. Moreover, we found that knockdown of circPIBF1 significantly suppressed the expression of SOD2 in cells and LUAD cell growth, while enhanced the expression of pyroptosis-related factors, which were further reversed by overexpression of SOD2 or EP300. Collectively, our findings suggest a direct involvement of circPIBF1 in pyroptosis-related LUAD carcinogenesis and implicate a role of Nrf2/EP300/SOD2 signaling in this process.

Screening of Natural Compounds Against SOD1 as a Therapeutic Target for Amyotrophic Lateral Sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is an uncommon and progressive neurological illness that predominantly includes the neurons liable for voluntary muscular activities. Starting from weakness or stiffness in muscles, this gradually exploits the strength and ability to speak, eat, move, and even breathe. Its exact mechanism is still not clear, but mutations in the SOD1 gene have been reported to cause ALS, and some studies also found involvement of SOD1 overexpression in the pathogenesis of ALS. As of now, there is no remedy available for its cure. Objective: The objective of this study is to identify the potential inhibitors for wild type 1HL5, l113T mutant, and A4V mutant of SOD1 (Superoxide Dismutase 1) protein. Methods: In this study, in silico approaches like virtual screening, molecular docking, pharmacokinetic parameters study, and molecular dynamics simulation were used to identify the best potential inhibitors against wild type and mutant SOD1 protein. Results: On the basis of binding affinity and binding energy, the top three compounds ZINC000095486263, ZINC000095485989, and ZINC000028462577 were observed as the best compounds. In the case of 1HL5, ZINC000095486263 had the highest binding affinity with docking score - 10.62 Kcal/mol, 1UXM with ZINC000095485989 had the highest docking score -12.03 Kcal/mol, and 4A7V with ZINC000028462577 was found -11.72 Kcal/mol. Further, Molecular Dynamic Simulations (MDS) results showed that the ZINC000095486263, ZINC000095485989, and ZINC000095485956 compounds were formed a stable complex with 1HL5, 1UXM, and 4A7V respectively. Conclusions: After analyzing the results, we hereby conclude that natural compounds such as ZINC000095486263, ZINC000095485989, and ZINC000095485956 could be used as a potential inhibitor of 1HL5, 1UXM, and 4A7V respectively for ALS treatment and could be used as a drug. Further, In vivo/vitro study of these compounds could be a future direction in the field of drug discovery.

Superoxide dismutase 2 ameliorates mitochondrial dysfunction in skin fibroblasts of Leber's hereditary optic neuropathy patients.

BackgroundIn Leber’s hereditary optic neuropathy (LHON), mtDNA mutations mediate mitochondrial dysfunction and apoptosis of retinal ganglion cells. Mitochondrial superoxide dismutase 2 (SOD2) is a crucial antioxidase against reactive oxygen species (ROS). This study aims to investigate whether SOD2 could ameliorate mtDNA mutation mediated mitochondrial dysfunction in skin fibroblasts of LHON patients and explore the underlying mechanisms.MethodsThe skin of normal healthy subjects and severe LHON patients harboring m.11778G > A mutation was taken to prepare immortalized skin fibroblast cell lines (control-iFB and LHON-iFB). LHON-iFB cells were transfected with SOD2 plasmid or negative control plasmid, respectively. In addition, human neuroblastoma SH-SY5Y cells and human primary retinal pigmental epithelium (hRPE) cells were stimulated by H2O2 after gene transfection. The oxygen consumption rate (OCR) was measured with a Seahorse extracellular flux analyzer. The level of ATP production, mitochondrial membrane potential, ROS and malondialdehyde (MDA) were measured separately with the corresponding assay kits. The expression level of SOD2, inflammatory cytokines and p-IκBα/IκBα was evaluated by western-blot. Assessment of apoptosis was performed by TUNEL assay.ResultsLHON-iFB exhibited lower OCR, ATP production, mitochondrial membrane potential but higher level of ROS and MDA than control-iFB. Western-blot revealed a significantly increased expression of IL-6 and p-IκBα/IκBα in LHON-iFB. Compared with the negative control, SOD2 overexpression increased OCR, ATP production and elevated mitochondrial membrane potential, but impaired ROS and MDA production. Besides, western-blot demonstrated exogenous SOD2 reduced the protein level of IL-6 and p-IκBα/IκBα. TUNEL assays suggested SOD2 inhibited cells apoptosis. Analogously, in SH-SY5Y and hRPE cells, SOD2 overexpression increased ATP production and mitochondrial membrane potential, but decreased ROS, MDA levels and suppressed apoptosis.ConclusionSOD2 upregulation inhibited cells apoptosis through ameliorating mitochondrial dysfunction and reducing NF-κB associated inflammatory response. This study further support exogenous SOD2 may be a promising therapy for the treatment of LHON.

Alteration of Mitochondrial Integrity as Upstream Event in the Pathophysiology of SOD1-ALS.

Little is known about the early pathogenic events by which mutant superoxide dismutase 1 (SOD1) causes amyotrophic lateral sclerosis (ALS). This lack of mechanistic understanding is a major barrier to the development and evaluation of efficient therapies. Although protein aggregation is known to be involved, it is not understood how mutant SOD1 causes degeneration of motoneurons (MNs). Previous research has relied heavily on the overexpression of mutant SOD1, but the clinical relevance of SOD1 overexpression models remains questionable. We used a human induced pluripotent stem cell (iPSC) model of spinal MNs and three different endogenous ALS-associated SOD1 mutations (D90Ahom, R115Ghet or A4Vhet) to investigate early cellular disturbances in MNs. Although enhanced misfolding and aggregation of SOD1 was induced by proteasome inhibition, it was not affected by activation of the stress granule pathway. Interestingly, we identified loss of mitochondrial, but not lysosomal, integrity as the earliest common pathological phenotype, which preceded elevated levels of insoluble, aggregated SOD1. A super-elongated mitochondrial morphology with impaired inner mitochondrial membrane potential was a unifying feature in mutant SOD1 iPSC-derived MNs. Impaired mitochondrial integrity was most prominent in mutant D90Ahom MNs, whereas both soluble disordered and detergent-resistant misfolded SOD1 was more prominent in R115Ghet and A4Vhet mutant lines. Taking advantage of patient-specific models of SOD1-ALS in vitro, our data suggest that mitochondrial dysfunction is one of the first crucial steps in the pathogenic cascade that leads to SOD1-ALS and also highlights the need for individualized medical approaches for SOD1-ALS.

Fibroblast growth factor 12 attenuated cardiac remodeling via suppressing oxidative stress

Fibroblast growth factors (FGFs) mediate key cardiac functions from development to homeostasis and disease. The current research was to explore the effects of FGF12 in the fibrosis of cardiac function and heart failure, and whether FGF12 alleviated cardiac fibrosis via inhibition of oxidative stress. Ligation of left coronary artery in mice induced heart failure and myocardial infarction (MI). Angiotensin II (Ang II) was administered to cardiac fibroblasts (CFs). FGF12 upregulation or FGF12 transgenic (Tg) mice could improve cardiac dysfunction of MI mice, and attenuated cardiac fibrosis of heart failure induced by MI in mice. FGF12 overexpression suppressed the increases of collagen I, collagen III and fibronectin which was induced by Ang II in CFs. The oxidative stress was enhanced in the heart of MI mice and CFs treated with Ang II, and these enhances were attenuated via FGF12 overexpression. Superoxide dismutase (SOD) overexpression inhibited the enhancements of collagen I, collagen III and fibronectin in the heart of MI mice, and in the CFs treated with Ang II. Overexpression of nicotinamide adenine dinucleotide phosphate oxidases (Nox1) reversed the attenuating influences of FGF12 on the enhancements of collagen I, collagen III and fibronectin in the CFs induced by Ang II. These outcomes showed that FGF12 upregulation can improve cardiac dysfunction and heart fibrosis of heart failure. FGF12 attenuates oxidative stress to suppress the cardiac fibrosis.