Addition of Reduced Glutathione (GSH) to Freezing Medium Reduces Intracellular ROS Levels in Donkey Sperm

In donkeys, the use of frozen-thawed sperm for artificial insemination (AI) leads to low fertility rates. Furthermore, donkey sperm produce a large amount of reactive oxygen species (ROS), and post-AI inflammation induces the formation of neutrophil extracellular traps (NETosis), which further generates many more ROS. These high ROS levels may induce lipid peroxidation in the sperm plasma membrane, thus affecting its integrity. Enzymatic and non-enzymatic antioxidants, mainly found in the seminal plasma (SP), are responsible for maintaining the redox balance. However, this fluid is removed prior to cryopreservation, thereby exposing sperm cells to further oxidative stress. The exogenous addition of antioxidants to the freezing medium can reduce the detrimental effects caused by ROS generation. Therefore, the aim of this study was to evaluate how the addition of different reduced glutathione (GSH) concentrations (control, 2 mM, 4 mM, 6 mM, 8 mM, and 10 mM) to fresh sperm affect their cryotolerance. Total and progressive motility, kinematic parameters and motile sperm subpopulations were significantly (p < 0.05) different from the control in treatments containing 8 mM and 10 mM GSH, but not at lower concentrations. Plasma and acrosome membrane integrity, mitochondrial membrane potential (MMP) and intracellular superoxide levels (O2−) were not affected (p > 0.05) by any GSH concentration. Interestingly, however, the addition of 8 mM or 10 mM GSH reduced (p < 0.05) the percentages of viable sperm with high overall ROS levels compared to the control. In conclusion, frozen-thawed donkey sperm are able to tolerate high GSH concentrations, which differs from what has been observed in other species. This antioxidant capacity suggests that ROS could be important during post-AI and that the impact of using exogenous antioxidants like GSH to improve the sperm resilience to freeze-thawing is limited in this species.

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Oxidative damage and antioxidants in cervical cancer

International Journal of Gynecological Cancer ◽

10.1136/ijgc-2020-001587 ◽

2020 ◽

pp. ijgc-2020-001587

Author(s):

Daciele Paola Preci ◽

Angélica Almeida ◽

Anne Liss Weiler ◽

Maria Luiza Mukai Franciosi ◽

Andréia Machado Cardoso

Keyword(s):

Cervical Cancer ◽

Superoxide Dismutase ◽

Glutathione Peroxidase ◽

Oxidative Damage ◽

Cancer Progression ◽

Reduced Glutathione ◽

Reactive Oxygen ◽

Enzymatic Antioxidants ◽

Glutathione S Transferase ◽

The Impact

The pathogenesis of cervical cancer is related to oxidative damage caused by persistent infection by one of the oncogenic types of human papillomavirus (HPV). This damage comes from oxidative stress, which is the imbalance caused by the increase in reactive oxygen and nitrogen species and impaired antioxidant mechanisms, promoting tumor progression through metabolic processes. The incorporation of HPV into the cellular genome leads to the expression of oncoproteins, which are associated with chronic inflammation and increased production of reactive oxygen species, oxidizing proteins, lipids and DNA. The increase in these parameters is related, in general, to the reduction of circulating levels of enzymatic antioxidants—superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase; and non-enzymatic antioxidants—reduced glutathione, coenzyme Q10 and vitamins A, C and E, according to tumor staging. In contrast, some enzymatic antioxidants suffer upregulation in the tumor tissue as a way of adapting to the oxidative environment generated by themselves, such as glutathione-S-transferase, reduced glutathione, glutathione peroxidase, superoxide dismutase 2, induced nitric oxide synthase, peroxiredoxins 1, 3 and 6, and thioredoxin reductase 2. The decrease in the expression and activity of certain circulatory antioxidants and increasing the redox status of the tumor cells are thus key to cervical carcinoma prognosis. In addition, vitamin deficit is considered a possible modifiable risk factor by supplementation, since the cellular functions can have a protective effect on the development of cervical cancer. In this review, we will discuss the impact of oxidative damage on cervical cancer progression, as well as the main oxidative markers and therapeutic potentialities of antioxidants.

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POTENTIAL ROLE OF HAEMATOCOCCUS PLUVIALIS AGAINST DIABETES INDUCED OXIDATIVE STRESS AND INFLAMMATION IN RATS

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10i1.15073 ◽

2016 ◽

Vol 10 (1) ◽

pp. 245

Author(s):

Farouk Kamel Elbaz ◽

Hanan F Aly ◽

Wagdy Kb Khalil ◽

Gamila H Al ◽

Naglaa A Hafiz ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetes Mellitus ◽

Antioxidant Enzyme ◽

Inflammatory Cytokines ◽

Dna Adducts ◽

Haematococcus Pluvialis ◽

Lipid Peroxide ◽

Ros Generation ◽

Enzymatic Antioxidants ◽

The Impact

ABSTRACTObjective: The aim of this study is to investigate the impact of Haematococcus pluvialis extract against oxidative stress and inflammatory cytokinesinduced by hyperglycemia in diabetic rats.Methods: Oxidative stress; lipid peroxide (as presented by Malondialdehyde; MDA) and nitric oxide (NO), beside total antioxidant capacity, enzymaticand non-enzymatic antioxidants including reduced glutathione, glutathione peroxidase, and glutathione reductase were evaluated. The inflammatorycytokines; tumor necrosis factor-alpha and interleukin-1 beta were also investigated in rats’ serum. Several analyses including expression ofantioxidant enzyme related genes, reactive oxygen species (ROS) formation and DNA adducts were performed.Results: The results showed that diabetes mellitus induced-rats exhibited increase in oxidative stress biomarkers and inflammatory cytokines, lowerexpression levels of the antioxidant enzyme genes; superoxide dismutase and glutathione S-transferase than those in control rats. In addition, diabeticrats exhibited significantly higher levels of ROS generation and 8-hydroxy-2’-deoxyguanosine (8-OHdG) formation. In contrary, supplementation ofdiabetic rats with H. pluvialis extract improved the negative effect of the hyperglycemia on antioxidant enzymes, the gene expression of antioxidantenzymes, and ROS generation as well as 8-OHdG formation.Conclusion: H. pluvialis extract decreased the oxidative stress, enhanced antioxidant status and inflammatory cytokines induced by hyperglycemiain diabetic rats. The effect of H. pluvialis extract involved in the increase of expression levels of antioxidant enzyme genes; decreased the levels of ROSgeneration and 8-OHdG formation which may be attributed to the presence of astaxanthin in H. pluvialis extract.Keywords: Haematococcus pluvialis, Hyperglycemia, Diabetes mellitus, Oxidative stress, Inflammatory cytokines, DNA adducts.

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85 ADDITION OF REDUCED GLUTATHIONE TO FREEZING MEDIUM IMPROVED THE SPERM FUNCTIONALITY OF THAWED BOAR SPERMATOZOA

Reproduction Fertility and Development ◽

10.1071/rdv17n2ab85 ◽

2005 ◽

Vol 17 (2) ◽

pp. 192

Author(s):

J. Gadea ◽

F. Garcia-Vázquez ◽

D. Gumbao ◽

F.A. Rodríguez ◽

C. Matás

Keyword(s):

Reduced Glutathione ◽

Egg Yolk ◽

Positive Influence ◽

Membrane Lipid ◽

Sulfhydryl Groups ◽

Ros Generation ◽

Freezing Medium ◽

Group 5 ◽

Physical And Chemical ◽

Boar Spermatozoa

The processes of cooling and freezing/thawing produce physical and chemical stresses on the sperm membrane that are associated with the oxidative stress and reactive oxygen species (ROS) generation that reduce sperm viability and fertilizing ability. It is known that the process of freezing is associated with a significant reduction of the GSH content in boar sperm (Gadea et al. 2004 Theriogenology 62, 690–701). The addition of antioxidants to freezing medium could prevent the formation of ROS and improve the seminal parameters. The aim of these experiments was to investigate the effects of the addition of reduced glutathione (GSH) to freezing extenders on capacitation status and changes in the sulfhydryl groups of proteins on the sperm surface. Ejaculate-rich fractions from three mature boars were frozen by classic methodology (Westendorf et al. 1975 Dtsch. Tierarztl Wochenschr. 82, 393–395) using lactose/egg-yolk extender with 0 mM (group 0), 1 mM (group 1), or 5 mM (group 5) GSH. To detect increase in plasma membrane lipid packing disorder, sperm samples were stained with merocyanine 540 (M540) and Yo-Pro 1 (Harrison et al. 1996 Mol. Reprod. Dev. 45, 378–391). Cells were classified as low M540 (viable, noncapacitated), high M540 (viable, capacitated), or Yo-Pro-1 positive (dead sperm) using flow cytometry. The sulfhydryl status of proteins from spermatozoa surface was evaluated with a fluorescent stain 5-iodoacetamidofluoresceine (5-IAF). The addition of GSH to the freezing medium had a positive influence on the parameters studied, increasing the proportion of viable noncapacitated spermatozoa and reducing the number of dead with a similar number of viable capacitated (Table 1). The proportion of spermatozoa stained by 5-IAF was significantly lower when GSH was added. In conclusion, we can assume that the addition of reduced glutathione to the freezing medium had a protective effect on spermatozoa functionality. Table 1. Capacitation status and changes in sulfhydryl groups of proteins (5-IAF staining) after thawing of frozen boar spermatozoa This work was supported by AGL- 2003-03144.

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106EVALUATION OF ADDITION OF REDUCED GLUTATHIONE TO COOLING MEDIUM ON IN VITRO FERTILITY AND ACROSOME REACTION IN BOAR SPERMATOZOA

Reproduction Fertility and Development ◽

10.1071/rdv16n1ab106 ◽

2004 ◽

Vol 16 (2) ◽

pp. 175

Author(s):

C. Matás ◽

J. Gadea ◽

F. García-Vázquez ◽

J.C. Gardón ◽

S. Cánovas

Keyword(s):

In Vitro Fertilization ◽

Acrosome Reaction ◽

Reduced Glutathione ◽

Membrane Integrity ◽

Calcium Ionophore ◽

Egg Yolk ◽

Ros Generation ◽

Vitro Fertilization ◽

Cooling Medium

The process of cooling to 5°C prior to freezing produces physical and chemical stress on the sperm membrane associated with oxidative stress and reactive oxygen species (ROS) generation that reduces sperm viability and fertilizing ability. The addition of antioxidants to cooling medium could prevent the formation of ROS and improve the seminal parameters. The aim of these experiments was to investigate the effects of addition of reduced glutathione (GSH) to cooling extenders on (1) plasma membrane integrity, (2) acrosome reaction induction by ionophore A 23187 or progesterone, and (3) in vitro fertilization. Ejaculate-rich fractions from three mature pietrain boars were diluted in Beltsville Thaw Solution (BTS) extender and cooled to 15°C over 2h (group C). Thereafter, sperm were centrifuged and diluted in lactose/egg-yolk extender with 0mM (group 0), 1mM (group 1) or 5mM (group 5) of GSH, cooled to 5°C over 2h. The acrosome reaction was then induced by 1μM calcium ionophore or 10μM progesterone in TALP medium and incubated in 5% CO2, 38.5°C for 30 or 45min, respectively. Membrane integrity was evaluated by propidium iodide, and acrosomal status was monitored by means of FITC-labeled peanut agglutinin. Finally, in vitro fertilization was performed with these four spermatozoa groups as described previously (Matás et al. 2003 Reproduction 125, 133–141). ANOVA analysis revealed that the addition of GSH had no effect on the membrane integrity (ranged 58.8 to 66.9) or acrosome reaction induction (ranged 24.3 to 28.2, and 55.7 to 41.4 for progesterone and calcium ionophore, respectively). However, the results of the penetration assay revealed that the cooling affected the penetration rate and the number of sperm per oocyte (Table 1), and this assay is better than the others to predict changes in the spermatozoa functionality (Gadea J and Matás C 2000 Theriogenology 54, 1343–1357). In conclusion, the cooling process affects the in vitro fertilization, but the addition of GSH to the medium did not influence the parameters studied. Supported by AGL2000-0485-CO2-01. Table 1 Homologous in vitro penetration

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The Effect of Sea Buckthorn (Hippophae rhamnoides L.) Seed Oil on UV-Induced Changes in Lipid Metabolism of Human Skin Cells

Antioxidants ◽

10.3390/antiox7090110 ◽

2018 ◽

Vol 7 (9) ◽

pp. 110 ◽

Cited By ~ 8

Author(s):

Agnieszka Gęgotek ◽

Anna Jastrząb ◽

Iwona Jarocka-Karpowicz ◽

Marta Muszyńska ◽

Elżbieta Skrzydlewska

Keyword(s):

Mass Spectrometry ◽

Lipid Metabolism ◽

Seed Oil ◽

Cannabinoid Receptor ◽

Redox Balance ◽

Sea Buckthorn ◽

Ros Generation ◽

Enzymatic Antioxidants ◽

Skin Cells ◽

Sea Buckthorn Oil

Lipids and proteins of skin cells are the most exposed to harmful ultraviolet (UV) radiation contained in sunlight. There is a growing need for natural compounds that will protect these sensitive molecules from damage, without harmful side effects. The aim of this study was to investigate the effect of sea buckthorn seed oil on the redox balance and lipid metabolism in UV irradiated cells formed different skin layers to examine whether it had a protective effect. Human keratinocytes and fibroblasts were subjected to UVA (ultraviolet type A; 30 J/cm2 and 20 J/cm2) or UVB (ultraviolet type B; 60 mJ/cm2 and 200 mJ/cm2, respectively) radiation and treated with sea buckthorn seed oil (500 ng/mL), and the redox activity was estimated by reactive oxygen species (ROS) generation and enzymatic/non-enzymatic antioxidants activity/level (using electron spin resonance (ESR), high-performance liquid chromatography (HPLC), and spectrophotometry). Lipid metabolism was measured by the level of fatty acids, lipid peroxidation products, endocannabinoids and phospholipase A2 activity (GC/MS (gas chromatography/mass spectrometry), LC/MS (liquid chromatography/mass spectrometry), and spectrophotometry). Also, transcription factor Nrf2 (nuclear erythroid 2-related factor) and its activators/inhibitors, peroxisome proliferator-activated receptors (PPAR) and cannabinoid receptor levels were measured (Western blot). Sea buckthorn oil partially prevents UV-induced ROS generation and enhances the level of non-enzymatic antioxidants such as glutathione (GSH), thioredoxin (Trx) and vitamins E and A. Moreover, it stimulates the activity of Nrf2 leading to enhanced antioxidant enzyme activity. As a result, decreases in lipid peroxidation products (4-hydroxynonenal, 8-isoprostaglandin) and increases in the endocannabinoid receptor levels were observed. Moreover, sea buckthorn oil treatment enhanced the level of phospholipid and free fatty acids, while simultaneously decreasing the cannabinoid receptor expression in UV irradiated keratinocytes and fibroblasts. The main differences in sea buckthorn oil on various skin cell types was observed in the case of PPARs—in keratinocytes following UV radiation PPAR expression was decreased by sea buckthorn oil treatment, while in fibroblasts the reverse effect was observed, indicating an anti-inflammatory effect. With these results, sea buckthorn seed oil exhibited prevention of UV-induced disturbances in redox balance as well as lipid metabolism in skin fibroblasts and keratinocytes, which indicates it is a promising natural compound in skin photo-protection.

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Modulation of biochemical and physiological parameters in Hordeum vulgare L. seedlings under the influence of benzyl-butyl phthalate

PeerJ ◽

10.7717/peerj.6742 ◽

2019 ◽

Vol 7 ◽

pp. e6742 ◽

Cited By ~ 4

Author(s):

Arpna Kumari ◽

Rajinder Kaur

Keyword(s):

Hordeum Vulgare ◽

Agricultural Soils ◽

Membrane Integrity ◽

Guaiacol Peroxidase ◽

Enzymatic Antioxidants ◽

Hordeum Vulgare L ◽

Sod Activity ◽

Benzyl Butyl Phthalate ◽

Butyl Phthalate ◽

The Impact

Background Phthalates are man-made chemical compounds with numerous applications especially known for their use as plasticizers. They have weak bonding to the polymeric matrix or products in which they are used. Owing to this reason, they are readily released into the environment which makes them ubiquitous. The agricultural soils are also reported to be polluted with phthalates up to a considerable extent which causes adverse effects on flora and fauna. A few studies have been conducted on phthalate-induced phytotoxicity, which has revealed that phthalates affect the quality and yield of edible plants. In the last decades, some crops were analyzed for phthalate-induced adversities; among them, barley was the least explored. Methods The present study has investigated the impact of benzyl-butyl phthalate (BBP) on barley (Hordeum vulgare L.) seedlings to address the biochemical, physiological consequences, and toxicological implications. After the exogenous exposure of BBP (viz. 0, 25, 50, 100, 200, 400, 800, 1,600 mg/L) for 7 days, barley seedlings were analyzed for different indices. Results The exposure of BBP mediated a significant (p ≤ 0.05, 0.01) overall elevation in the contents of pigment, proline, soluble protein, carbohydrate, hydrogen peroxide (H2O2), and malondialdehyde (MDA) in shoots and roots of barley seedlings. The activities of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) were also stimulated significantly in shoots and roots of seedlings against BBP stress except for SOD activity which declined in the roots. The polyphenols (non-enzymatic antioxidants) content was also altered in all the treated concentrations as compared to the control. Furthermore, BBP caused stomatal abnormalities, induced cytotoxicity, and loss of plasma membrane integrity. Conclusions BBP disturbed the normal physiology of barley which could also affect the yield of the crop under field conditions.

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The Impact of Bacteriocenoses on Sperm Vitality, Immunological and Oxidative Characteristics of Ram Ejaculates: Does the Breed Play a Role?

Animals ◽

10.3390/ani12010054 ◽

2021 ◽

Vol 12 (1) ◽

pp. 54

Author(s):

Eva Tvrdá ◽

Miroslava Kačániová ◽

Andrej Baláži ◽

Jaromír Vašíček ◽

Jakub Vozaf ◽

...

Keyword(s):

Structural Integrity ◽

Semen Quality ◽

Pearson Correlation ◽

Interleukin 1 ◽

Bacterial Load ◽

Membrane Integrity ◽

Ros Generation ◽

Male Gametes ◽

And Function ◽

The Impact

Bacterial contamination of semen is an often overlooked, yet important, factor contributing to decreased sperm vitality. Understanding the impact of bacterial presence on sperm structural integrity and functional activity may assist the development of effective strategies to prevent, or manage, bacteriospermia in the breeding practice. The aim of this study was to describe the bacterial profiles of ram semen (n = 35), and we also focused on the associations between bacteriospermia, sperm structure, and function, as well as oxidative and inflammatory characteristics of semen. For a better insight, the samples were divided into three groups, according to the breeds used in the study: native Wallachian (NW), improved Wallachian (IW), and Slovak dairy (SD) breeds. The results showed a significantly lower motility and membrane integrity in the NW group in comparison to the IW and SD groups, which was accompanied by a significantly higher concentration of leukocytes, increased reactive oxygen species (ROS) generation, and subsequent oxidative insults to the sperm lipids and proteins. Accordingly, the NW group presented with the highest bacterial load, in which Staphylococcus and Escherichia were the predominant representatives. The Pearson correlation analysis uncovered positive relationships amongst the bacterial load and leukocytospermia (r = 0.613), the extent of lipid peroxidation (r = 0.598), protein oxidation (r = 0.514), and DNA fragmentation (r = 0.638). Furthermore, positive correlations were found between the bacterial load and pro-inflammatory molecules, such as the C-reactive protein (r = 0.592), interleukin 1 (r = 0.709), and interleukin 6 (r = 0.474), indicating a possible involvement of the immune response in the process of bacteriospermia. Overall, our data indicate that ram semen quality may be equally affected by the bacterial load and diversity. Furthermore, we can assume that the presence of bacteria in ejaculates triggers inflammatory processes, causes ROS overproduction, and, thereby, contributes to alterations in the sperm structure, while at the same time compromising the fertilization ability of male gametes.

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Effect of Antioxidants on Pig Semen Cryopreservation to Preserve Sperm Fertility after Thawing

Annals of Agricultural & Crop Sciences ◽

10.26420/annagriccropsci.2021.1090 ◽

2021 ◽

Vol 6 (5) ◽

Author(s):

da Costa Silva RJ ◽

◽

da Silva MHM ◽

Valadão L ◽

da Silva FM ◽

...

Keyword(s):

Ascorbic Acid ◽

Sperm Motility ◽

Reduced Glutathione ◽

Control Group ◽

Sperm Viability ◽

Entire Study ◽

Semen Cryopreservation ◽

Freezing Medium ◽

Microscopic Evaluation ◽

The Impact

Boar semen cryopreservation has a high potential in the swine industry, allowing the large-scale use of genetically superior animals, improving efficiency, product quality, helping to reduce the risk of disease spread and gathering needs from the market. From a genetic point of view, semen freezing is desirable for genetic diversification, favouring a more efficient reproduction as well as the constitution of germplasm banks, including for repopulation in case of disease outbreak. However, freezing this semen for long periods for practical use is limited by the reduced viability and fertilization potential caused to sperm during the cryopreservation process and consequently low conception rates and smaller litters after artificial insemination. In part, the decrease in the fertilizing power of frozen spermatozoa may be associated with oxidative damage due to excessive formation of Reactive Oxygen Species (ROS), osmotic stress and cell damage due to ice formation during cryopreservation. To suppress the damage caused by ROS, the present study was conducted to determine the impact of supplementation with three antioxidants, these being ascorbic acid, a-tocopherol and reduced glutathione, evaluating the parameters of semen quality, viability, total and progressive motility, vigour and agglutination rate after thawing. For this purpose, semen was collected from five boars, each being collected three times, at weekly intervals, always at the same time. Immediately after harvesting, the macroscopic (colour, appearance, and volume) and microscopic evaluation of the semen (mass motility, concentration, progressive individual motility, spermatic vigour and spermatic morphology) were evaluated. Subsequently, the semen was placed at 15°C for two hours and centrifuged at 800 x g for 10 minutes also at 15°C, removing the supernatant. For the freezing medium, a base medium consisting of a commercial MR-A extender, supplemented with 3% v/v glycerol, 10% v/v egg yolk and 0.20% w/v Sodium Dodecyl Sulfate (SDS) was used. The nine treatments used in the study were, respectively, ascorbic acid at concentrations of 100, 200 and 400μL, a-Tocopherol at concentrations of 200, 400 and 800μM and reduced Glutathione at concentrations of 2.5, 5 and 10 mg/l and numbered as T1 to T9, respectively. In the control group, semen was frozen in a medium without adding any antioxidant. The semen belonging to the different treatments and to the control was placed in 0.25ml insemination French straws and incubated at 6°C for two hours. The subsequent freezing was carried out in nitrogen vapours (-120°C) for ten minutes and immersed in liquid nitrogen after this period. After 7 days, the semen was thawed in a water bath at 37°C for 20 seconds, the straws dried on paper, placed on a microscope slide heated to 37°C and evaluated according to the parameters described above. Regarding the comparison between the different treatments, it was observed that the sperm viability obtained in the treatments with ascorbic acid as well as glutathione reduced, was not statistically different from the control group. Higher values of ascorbic acid and reduced glutathione reduced sperm viability after thawing. As for the use of a-tocopherol at a concentration of 400μM, the best results of the entire study were obtained, with sperm viability of 31.52% (±1.50). Regarding sperm motility and agglutination rate, a-tocopherol also showed the best results at the concentration of 200μM, in which the mean sperm motility was 2.57 ± 0.15 and 2.07 ± 0.15, respectively. The results of the present study allow us to infer that the addition of 200μM or 400μM of a-tocopherol to the swine semen-freezing medium has a positive effect on sperm viability parameters after thawing.

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ATP13A2 Regulates Cellular α-Synuclein Multimerization, Membrane Association, and Externalization

International Journal of Molecular Sciences ◽

10.3390/ijms22052689 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2689

Author(s):

Jianmin Si ◽

Chris Van den Haute ◽

Evy Lobbestael ◽

Shaun Martin ◽

Sarah van Veen ◽

...

Keyword(s):

Membrane Integrity ◽

Ubiquitin Proteasome System ◽

Regulatory Function ◽

Membrane Association ◽

Loss Of Function ◽

Atypical Form ◽

Polyamine Transport ◽

Independent Functions ◽

Ubiquitin Proteasome ◽

The Impact

ATP13A2, a late endo-/lysosomal polyamine transporter, is implicated in a variety of neurodegenerative diseases, including Parkinson’s disease and Kufor–Rakeb syndrome, an early-onset atypical form of parkinsonism. Loss-of-function mutations in ATP13A2 result in lysosomal deficiency as a consequence of impaired lysosomal export of the polyamines spermine/spermidine. Furthermore, accumulating evidence suggests the involvement of ATP13A2 in regulating the fate of α-synuclein, such as cytoplasmic accumulation and external release. However, no consensus has yet been reached on the mechanisms underlying these effects. Here, we aimed to gain more insight into how ATP13A2 is linked to α-synuclein biology in cell models with modified ATP13A2 activity. We found that loss of ATP13A2 impairs lysosomal membrane integrity and induces α-synuclein multimerization at the membrane, which is enhanced in conditions of oxidative stress or exposure to spermine. In contrast, overexpression of ATP13A2 wildtype (WT) had a protective effect on α-synuclein multimerization, which corresponded with reduced αsyn membrane association and stimulation of the ubiquitin-proteasome system. We also found that ATP13A2 promoted the secretion of α-synuclein through nanovesicles. Interestingly, the catalytically inactive ATP13A2 D508N mutant also affected polyubiquitination and externalization of α-synuclein multimers, suggesting a regulatory function independent of the ATPase and transport activity. In conclusion, our study demonstrates the impact of ATP13A2 on α-synuclein multimerization via polyamine transport dependent and independent functions.

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Neurotrophins as Key Regulators of Cell Metabolism: Implications for Cholesterol Homeostasis

International Journal of Molecular Sciences ◽

10.3390/ijms22115692 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5692

Author(s):

Mayra Colardo ◽

Noemi Martella ◽

Daniele Pensabene ◽

Silvia Siteni ◽

Sabrina Di Bartolomeo ◽

...

Keyword(s):

Growth Factors ◽

Cholesterol Metabolism ◽

System Development ◽

Cell Metabolism ◽

Redox Balance ◽

Nervous System Development ◽

Cholesterol Homeostasis ◽

Signaling Cascades ◽

Target Cells ◽

The Impact

Neurotrophins constitute a family of growth factors initially characterized as predominant mediators of nervous system development, neuronal survival, regeneration and plasticity. Their biological activity is promoted by the binding of two different types of receptors, leading to the generation of multiple and variegated signaling cascades in the target cells. Increasing evidence indicates that neurotrophins are also emerging as crucial regulators of metabolic processes in both neuronal and non-neuronal cells. In this context, it has been reported that neurotrophins affect redox balance, autophagy, glucose homeostasis and energy expenditure. Additionally, the trophic support provided by these secreted factors may involve the regulation of cholesterol metabolism. In this review, we examine the neurotrophins’ signaling pathways and their effects on metabolism by critically discussing the most up-to-date information. In particular, we gather experimental evidence demonstrating the impact of these growth factors on cholesterol metabolism.

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