The International Natural Product Sciences Taskforce (INPST) and the power of Twitter networking exemplified through #INPST hashtag analysis

Background: The development of digital technologies and the evolution of open innovation approaches have enabled the creation of diverse virtual organizations and enterprises coordinating their activities primarily online. The open innovation platform titled "International Natural Product Sciences Taskforce" (INPST) was established in 2018, to bring together in collaborative environment individuals and organizations interested in natural product scientific research, and to empower their interactions by using digital communication tools. Methods: In this work, we present a general overview of INPST activities and showcase the specific use of Twitter as a powerful networking tool that was used to host a one-week "2021 INPST Twitter Networking Event" (spanning from 31st May 2021 to 6th June 2021) based on the application of the Twitter hashtag #INPST. Results and Conclusion: The use of this hashtag during the networking event period was analyzed with Symplur Signals (https://www.symplur.com/), revealing a total of 6,036 tweets, shared by 686 users, which generated a total of 65,004,773 impressions (views of the respective tweets). This networking event's achieved high visibility and participation rate showcases a convincing example of how this social media platform can be used as a highly effective tool to host virtual Twitter-based international biomedical research events

Implication du stress oxydatif, de l’inflammation, du dysfonctionnement mitochondrial et peroxysomal dans le vieillissement musculaire : Aspects Biologiques et Cliniques

Aging is characterized by a progressive increase in oxidative stress, which promotes lipid peroxidation and the formation of oxidative derivatives of cholesterol, including 7β-hydroxycholesterol (7β-946;-OHC; CID 473141) and 7-ketocholesterol (7KC; CID 91474). These oxysterols, known to activate oxidative stress, inflammation, and cell death, may contribute to the aging process and age-related diseases, such as sarcopenia, which is a loss of muscle mass, strength, and function. The identification of molecules or mixtures of molecules preventing 7β-OHC and 7KC toxicity is, therefore, an important issue.In this context, a clinical study (case-control) on plasma and erythrocytes of sarcopenic and non-sarcopenic patients from the area of Monastir and Sousse (Tunisia) was performed. Different parameters were studied: oxidative stress biomarkers, non-specific (TNF-α, IL-6, IL-8, LTB-4) and specific (myokine: apelin) inflammation and lipid biomarkers (fatty acids, oxysterols). Subsequently, a study on the chemical composition and antioxidant properties of two Mediterranean oils (Pistacia lentiscus seed oil (PLSO); Sylibum marianum / Milk thistle seed oil (MTSO)) was performed. In addition, on murine C2C12 myoblasts and myotubes, the cytotoxic effects of 7β-OHC and 7KC (50 µM; 24 h) were studied (oxidative stress, effects on organelles (mitochondria, peroxisome), cell death) and the cytoprotective activities of PLSO, MTSO and α-tocopherol were characterized.In the clinical study, the results showed a significant increase in antioxidant enzyme activities, lipid and protein peroxidation products, and inflammation markers in sarcopenic patients as well as altered fatty acid profile and increased oxysterols levels (7β-OHC, 7KC). The oils (PLSO, MTSO) are rich in bioactive compounds; polyunsaturated fatty acids, and nutrients with antioxidant properties: phytosterols, α-tocopherol, carotenoids, flavonoids, and phenolic compounds. When PLSO and MTSO are associated with 7β-OHC and 7KC, the cytotoxic effects induced by these oxysterols are strongly attenuated and similar to those observed with α-tocopherol. These cytoprotective effects are characterized by: inhibition of oxidative stress (decrease of reactive oxygen species overproduction at the mitochondrial level and on whole-cell; decrease of lipid peroxidation and protein carbonylation; normalization of antioxidant enzymatic activities); an attenuation of mitochondrial and peroxisomal dysfunction and an inhibition of caspase-independent cell death associated with survival autophagy.These studies provide information on oxidative stress, inflammation, and lipid status in sarcopenic patients. On differentiated and undifferentiated C2C12 cells, 7β-OHC and 7KC induce an important oxidative stress associated with organelles dysfunction leading to a mode of cell death considered as ferroptosis. These different cytotoxic effects are strongly attenuated by PLSO and MTSO as well as α-tocopherol.All the results provide new information on the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease.Le vieillissement se caractérise par une augmentation progressive du stress oxydant, qui favorise la peroxydation des lipides et la formation de dérivés d’oxydation du cholestérol, dont le 7β-hydroxycholestérol (7β-OHC ; CID 473141) et le 7-cétocholestérol (7KC ; CID 91474). Ces oxystérols, connus pour activer le stress oxydant, l'inflammation et la mort cellulaire, pourraient contribuer au processus de vieillissement et aux maladies liées à l'âge, comme la sarcopénie qui est une perte de la masse, de la force et de la fonction musculaire. L'identification de molécules ou de mélanges de molécules prévenant la toxicité du 7β-OHC et du 7KC est donc un enjeu important.Dans ce contexte, une étude clinique (cas-témoin) sur le plasma et les érythrocytes de patients sarcopéniques et non sarcopéniques de la région de Monastir et Sousse (Tunisie) a été réalisée pour rechercher des paramètres de stress oxydant, d’inflammation non spécifique (TNF-α, IL-6, IL-8, LTB-4) et spécifique (myokine : apeline) et des marqueurs lipidiques (acides gras, oxystérols) en association avec la sarcopénie. Par la suite, une étude sur la composition chimique et les propriétés antioxydantes de deux huiles Méditerranéennes (Pistacia lentiscus seed oil (PLSO) ; Sylibum marianum / milk thistle seed oil (MTSO)) a été réalisée. De plus, sur des myoblastes et des myotubes C2C12 murins, les effets cytotoxiques du 7β-OHC et 7KC (50 µM ; 24 h) incluant le stress oxydant, les effets sur les organites (mitochondrie, peroxysome) et/ou l’activation de la mort cellulaire ont été caractérisés ainsi que les activités cytoprotectrices de PLSO et MTSO et de l'α-tocophérol.Dans l’étude clinique, les résultats ont montré une augmentation significative des activités enzymatiques antioxydantes, des produits de peroxydation lipidique et protéique et des marqueurs d’inflammation chez les patients sarcopéniques avec une altération du profil des acides gras et une augmentation d’oxystérols (7β-OHC, 7KC). Les huiles (PLSO, MTSO) sont riches en composés bioactifs ; acides gras polyinsaturés, et nutriments aux propriétés antioxydantes : phytostérols, α-tocophérol, caroténoïdes, flavonoïdes et composés phénoliques. Quand ces huiles sont associées au 7β-OHC et 7KC, les effets cytotoxiques induits par ces oxystérols sont très fortement atténués et semblables à ceux observés avec l'α-tocophérol. Ces effets cytoprotecteurs sont caractérisés par : une inhibition du stress oxydant (diminution de la surproduction d'espèces réactives de l'oxygène au niveau mitochondrial et sur cellule entière ; diminution de la peroxydation lipidique et la carbonylation protéique ; normalisation des activités enzymatiques antioxydantes) ; une atténuation des dysfonctionnement mitochondriaux et peroxysomaux et une inhibition de la mort cellulaire indépendante des caspases (ferroptose) associée à une autophagie de survie.Cette étude apporte des informations sur le stress oxydant, l’inflammation et le statut lipidique chez les patients sarcopéniques. In vitro, l’utilisation de cellules C2C12 différenciées ou non, a permis de démontrer que le 7β-OHC et le 7KC, augmentés dans le plasma des patients sarcopéniques, sont cytotoxiques et que leurs effets sont fortement atténués par le PLSO et le MTSO ainsi que l'α-tocophérol.Les résultats obtenus apportent des informations nouvelles sur la physiopathologie de la sarcopénie et ouvrent de nouvelles perspectives de traitement pour cette maladie liée à l’âge

Implication du stress oxydatif, de l’inflammation, du dysfonctionnement mitochondrial et peroxysomal dans le vieillissement musculaire : Aspects Biologiques et Cliniques

Aging is characterized by a progressive increase in oxidative stress, which promotes lipid peroxidation and the formation of oxidative derivatives of cholesterol, including 7β-hydroxycholesterol (7β-946;-OHC; CID 473141) and 7-ketocholesterol (7KC; CID 91474). These oxysterols, known to activate oxidative stress, inflammation, and cell death, may contribute to the aging process and age-related diseases, such as sarcopenia, which is a loss of muscle mass, strength, and function. The identification of molecules or mixtures of molecules preventing 7β-OHC and 7KC toxicity is, therefore, an important issue.In this context, a clinical study (case-control) on plasma and erythrocytes of sarcopenic and non-sarcopenic patients from the area of Monastir and Sousse (Tunisia) was performed. Different parameters were studied: oxidative stress biomarkers, non-specific (TNF-α, IL-6, IL-8, LTB-4) and specific (myokine: apelin) inflammation and lipid biomarkers (fatty acids, oxysterols). Subsequently, a study on the chemical composition and antioxidant properties of two Mediterranean oils (Pistacia lentiscus seed oil (PLSO); Sylibum marianum / Milk thistle seed oil (MTSO)) was performed. In addition, on murine C2C12 myoblasts and myotubes, the cytotoxic effects of 7β-OHC and 7KC (50 µM; 24 h) were studied (oxidative stress, effects on organelles (mitochondria, peroxisome), cell death) and the cytoprotective activities of PLSO, MTSO and α-tocopherol were characterized.In the clinical study, the results showed a significant increase in antioxidant enzyme activities, lipid and protein peroxidation products, and inflammation markers in sarcopenic patients as well as altered fatty acid profile and increased oxysterols levels (7β-OHC, 7KC). The oils (PLSO, MTSO) are rich in bioactive compounds; polyunsaturated fatty acids, and nutrients with antioxidant properties: phytosterols, α-tocopherol, carotenoids, flavonoids, and phenolic compounds. When PLSO and MTSO are associated with 7β-OHC and 7KC, the cytotoxic effects induced by these oxysterols are strongly attenuated and similar to those observed with α-tocopherol. These cytoprotective effects are characterized by: inhibition of oxidative stress (decrease of reactive oxygen species overproduction at the mitochondrial level and on whole-cell; decrease of lipid peroxidation and protein carbonylation; normalization of antioxidant enzymatic activities); an attenuation of mitochondrial and peroxisomal dysfunction and an inhibition of caspase-independent cell death associated with survival autophagy.These studies provide information on oxidative stress, inflammation, and lipid status in sarcopenic patients. On differentiated and undifferentiated C2C12 cells, 7β-OHC and 7KC induce an important oxidative stress associated with organelles dysfunction leading to a mode of cell death considered as ferroptosis. These different cytotoxic effects are strongly attenuated by PLSO and MTSO as well as α-tocopherol.All the results provide new information on the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease.Le vieillissement se caractérise par une augmentation progressive du stress oxydant, qui favorise la peroxydation des lipides et la formation de dérivés d’oxydation du cholestérol, dont le 7β-hydroxycholestérol (7β-OHC ; CID 473141) et le 7-cétocholestérol (7KC ; CID 91474). Ces oxystérols, connus pour activer le stress oxydant, l'inflammation et la mort cellulaire, pourraient contribuer au processus de vieillissement et aux maladies liées à l'âge, comme la sarcopénie qui est une perte de la masse, de la force et de la fonction musculaire. L'identification de molécules ou de mélanges de molécules prévenant la toxicité du 7β-OHC et du 7KC est donc un enjeu important.Dans ce contexte, une étude clinique (cas-témoin) sur le plasma et les érythrocytes de patients sarcopéniques et non sarcopéniques de la région de Monastir et Sousse (Tunisie) a été réalisée pour rechercher des paramètres de stress oxydant, d’inflammation non spécifique (TNF-α, IL-6, IL-8, LTB-4) et spécifique (myokine : apeline) et des marqueurs lipidiques (acides gras, oxystérols) en association avec la sarcopénie. Par la suite, une étude sur la composition chimique et les propriétés antioxydantes de deux huiles Méditerranéennes (Pistacia lentiscus seed oil (PLSO) ; Sylibum marianum / milk thistle seed oil (MTSO)) a été réalisée. De plus, sur des myoblastes et des myotubes C2C12 murins, les effets cytotoxiques du 7β-OHC et 7KC (50 µM ; 24 h) incluant le stress oxydant, les effets sur les organites (mitochondrie, peroxysome) et/ou l’activation de la mort cellulaire ont été caractérisés ainsi que les activités cytoprotectrices de PLSO et MTSO et de l'α-tocophérol.Dans l’étude clinique, les résultats ont montré une augmentation significative des activités enzymatiques antioxydantes, des produits de peroxydation lipidique et protéique et des marqueurs d’inflammation chez les patients sarcopéniques avec une altération du profil des acides gras et une augmentation d’oxystérols (7β-OHC, 7KC). Les huiles (PLSO, MTSO) sont riches en composés bioactifs ; acides gras polyinsaturés, et nutriments aux propriétés antioxydantes : phytostérols, α-tocophérol, caroténoïdes, flavonoïdes et composés phénoliques. Quand ces huiles sont associées au 7β-OHC et 7KC, les effets cytotoxiques induits par ces oxystérols sont très fortement atténués et semblables à ceux observés avec l'α-tocophérol. Ces effets cytoprotecteurs sont caractérisés par : une inhibition du stress oxydant (diminution de la surproduction d'espèces réactives de l'oxygène au niveau mitochondrial et sur cellule entière ; diminution de la peroxydation lipidique et la carbonylation protéique ; normalisation des activités enzymatiques antioxydantes) ; une atténuation des dysfonctionnement mitochondriaux et peroxysomaux et une inhibition de la mort cellulaire indépendante des caspases (ferroptose) associée à une autophagie de survie.Cette étude apporte des informations sur le stress oxydant, l’inflammation et le statut lipidique chez les patients sarcopéniques. In vitro, l’utilisation de cellules C2C12 différenciées ou non, a permis de démontrer que le 7β-OHC et le 7KC, augmentés dans le plasma des patients sarcopéniques, sont cytotoxiques et que leurs effets sont fortement atténués par le PLSO et le MTSO ainsi que l'α-tocophérol.Les résultats obtenus apportent des informations nouvelles sur la physiopathologie de la sarcopénie et ouvrent de nouvelles perspectives de traitement pour cette maladie liée à l’âge

Involvement of Oxidative Stress, Inflammation, Mitochondrial and Peroxysomal Dysfunction in Skeletal Muscle Aging : Biological and Clinical Aspects

Le vieillissement se caractérise par une augmentation progressive du stress oxydant, qui favorise la peroxydation des lipides et la formation de dérivés d’oxydation du cholestérol, dont le 7β-hydroxycholestérol (7β-OHC ; CID 473141) et le 7-cétocholestérol (7KC ; CID 91474). Ces oxystérols, connus pour activer le stress oxydant, l'inflammation et la mort cellulaire, pourraient contribuer au processus de vieillissement et aux maladies liées à l'âge, comme la sarcopénie qui est une perte de la masse, de la force et de la fonction musculaire. L'identification de molécules ou de mélanges de molécules prévenant la toxicité du 7β-OHC et du 7KC est donc un enjeu important.Dans ce contexte, une étude clinique (cas-témoin) sur le plasma et les érythrocytes de patients sarcopéniques et non sarcopéniques de la région de Monastir et Sousse (Tunisie) a été réalisée pour rechercher des paramètres de stress oxydant, d’inflammation non spécifique (TNF-α, IL-6, IL-8, LTB-4) et spécifique (myokine : apeline) et des marqueurs lipidiques (acides gras, oxystérols) en association avec la sarcopénie. Par la suite, une étude sur la composition chimique et les propriétés antioxydantes de deux huiles Méditerranéennes (Pistacia lentiscus seed oil (PLSO) ; Sylibum marianum / milk thistle seed oil (MTSO)) a été réalisée. De plus, sur des myoblastes et des myotubes C2C12 murins, les effets cytotoxiques du 7β-OHC et 7KC (50 µM ; 24 h) incluant le stress oxydant, les effets sur les organites (mitochondrie, peroxysome) et/ou l’activation de la mort cellulaire ont été caractérisés ainsi que les activités cytoprotectrices de PLSO et MTSO et de l'α-tocophérol.Dans l’étude clinique, les résultats ont montré une augmentation significative des activités enzymatiques antioxydantes, des produits de peroxydation lipidique et protéique et des marqueurs d’inflammation chez les patients sarcopéniques avec une altération du profil des acides gras et une augmentation d’oxystérols (7β-OHC, 7KC). Les huiles (PLSO, MTSO) sont riches en composés bioactifs ; acides gras polyinsaturés, et nutriments aux propriétés antioxydantes : phytostérols, α-tocophérol, caroténoïdes, flavonoïdes et composés phénoliques. Quand ces huiles sont associées au 7β-OHC et 7KC, les effets cytotoxiques induits par ces oxystérols sont très fortement atténués et semblables à ceux observés avec l'α-tocophérol. Ces effets cytoprotecteurs sont caractérisés par : une inhibition du stress oxydant (diminution de la surproduction d'espèces réactives de l'oxygène au niveau mitochondrial et sur cellule entière ; diminution de la peroxydation lipidique et la carbonylation protéique ; normalisation des activités enzymatiques antioxydantes) ; une atténuation des dysfonctionnement mitochondriaux et peroxysomaux et une inhibition de la mort cellulaire indépendante des caspases (ferroptose) associée à une autophagie de survie.Cette étude apporte des informations sur le stress oxydant, l’inflammation et le statut lipidique chez les patients sarcopéniques. In vitro, l’utilisation de cellules C2C12 différenciées ou non, a permis de démontrer que le 7β-OHC et le 7KC, augmentés dans le plasma des patients sarcopéniques, sont cytotoxiques et que leurs effets sont fortement atténués par le PLSO et le MTSO ainsi que l'α-tocophérol.Les résultats obtenus apportent des informations nouvelles sur la physiopathologie de la sarcopénie et ouvrent de nouvelles perspectives de traitement pour cette maladie liée à l’âge.Aging is characterized by a progressive increase in oxidative stress, which promotes lipid peroxidation and the formation of oxidative derivatives of cholesterol, including 7β-hydroxycholesterol (7β-946;-OHC; CID 473141) and 7-ketocholesterol (7KC; CID 91474). These oxysterols, known to activate oxidative stress, inflammation, and cell death, may contribute to the aging process and age-related diseases, such as sarcopenia, which is a loss of muscle mass, strength, and function. The identification of molecules or mixtures of molecules preventing 7β-OHC and 7KC toxicity is, therefore, an important issue.In this context, a clinical study (case-control) on plasma and erythrocytes of sarcopenic and non-sarcopenic patients from the area of Monastir and Sousse (Tunisia) was performed. Different parameters were studied: oxidative stress biomarkers, non-specific (TNF-α, IL-6, IL-8, LTB-4) and specific (myokine: apelin) inflammation and lipid biomarkers (fatty acids, oxysterols). Subsequently, a study on the chemical composition and antioxidant properties of two Mediterranean oils (Pistacia lentiscus seed oil (PLSO); Sylibum marianum / Milk thistle seed oil (MTSO)) was performed. In addition, on murine C2C12 myoblasts and myotubes, the cytotoxic effects of 7β-OHC and 7KC (50 µM; 24 h) were studied (oxidative stress, effects on organelles (mitochondria, peroxisome), cell death) and the cytoprotective activities of PLSO, MTSO and α-tocopherol were characterized.In the clinical study, the results showed a significant increase in antioxidant enzyme activities, lipid and protein peroxidation products, and inflammation markers in sarcopenic patients as well as altered fatty acid profile and increased oxysterols levels (7β-OHC, 7KC). The oils (PLSO, MTSO) are rich in bioactive compounds; polyunsaturated fatty acids, and nutrients with antioxidant properties: phytosterols, α-tocopherol, carotenoids, flavonoids, and phenolic compounds. When PLSO and MTSO are associated with 7β-OHC and 7KC, the cytotoxic effects induced by these oxysterols are strongly attenuated and similar to those observed with α-tocopherol. These cytoprotective effects are characterized by: inhibition of oxidative stress (decrease of reactive oxygen species overproduction at the mitochondrial level and on whole-cell; decrease of lipid peroxidation and protein carbonylation; normalization of antioxidant enzymatic activities); an attenuation of mitochondrial and peroxisomal dysfunction and an inhibition of caspase-independent cell death associated with survival autophagy.These studies provide information on oxidative stress, inflammation, and lipid status in sarcopenic patients. On differentiated and undifferentiated C2C12 cells, 7β-OHC and 7KC induce an important oxidative stress associated with organelles dysfunction leading to a mode of cell death considered as ferroptosis. These different cytotoxic effects are strongly attenuated by PLSO and MTSO as well as α-tocopherol.All the results provide new information on the pathophysiology of sarcopenia and open new perspectives for the treatment of this frequent age-related disease

Oxiapoptophagy in Age-Related Diseases. Comment on Ouyang et al. 7-Ketocholesterol Induces Oxiapoptophagy and Inhibits Osteogenic Differentiation in MC3T3-E1 Cells. Cells 2022, 11, 2882

Due to the increase in life span and life expectancy, which can, however, be more or less pronounced depending on the economic, social and cultural context [...

Evaluation of pro-inflammatory cytokines in frail Tunisian older adults.

The present study was undertaken to evaluate serum levels of pro-inflammatory cytokines in Tunisian older adults and to examine the relationships between inflammatory marker levels, geriatric, and biochemical parameters. A cross-sectional study was conducted in a population of Tunisian older adults (N = 141, aged 65 and over). Patients were recruited from the Department of Internal Medicine, Fattouma Bourguiba University Hospital (Monastir, Tunisia) and from a nursing home (Sousse, Tunisia). Comprehensive geriatric assessment, history taking and examination including functional and nutritional assessment were done for each participant. Enzyme-linked immunosorbent assay (ELISA) test was used to measure serum cytokine (TNF-α, IL-8, IL-6) levels. The modified Short Emergency Geriatric Assessment score (SEGAm) were used to classify patients as 51 very-frail, 40 frail, and 50 non-frail. The age of the participants (80 men, 61 women) ranged from 65 to 97 years. Serum levels of TNF-α, IL-8 and C-reactive protein (CRP) were significantly higher in very-frail participants compared to frail and non-frail ones. However, no significant differences in IL-6 levels were detected among frailty groups. After adjustment for age, CRP and IL-8 levels remained significantly associated with frailty. Analysis of the receiver operating characteristic (ROC) curve corresponding to IL-8 showed an area under the curve of 0.7 (p = 0.003; 95% CI [0.58-0.81]) and a predictive threshold of 5.27 pg/ml. Positive correlations were found between frailty score, IL-6, and IL-8 levels. In addition, a significant positive correlation was observed between IL-8 levels and Timed Up and Go test results. However, a negative correlation was observed between Mini Nutritional Assessment Short-Form score, IL-6 and CRP levels, as well as between Activities of Daily Living score and serum levels of TNF-α, IL-6, and CRP. In conclusion, the key findings of this study collectively support a role of pro-inflammatory cytokines, TNF-α, CRP, and especially IL-8 in the development of frailty in older adults

Plasma Activated Media for Prostate Cancer

International audienc

Role of Bioactive Compounds in the Regulation of Mitochondrial Dysfunctions in Brain and Age-Related Neurodegenerative Diseases

Mitochondria are multifunctional organelles that participate in a wide range of metabolic processes, including energy production and biomolecule synthesis. The morphology and distribution of intracellular mitochondria change dynamically, reflecting a cell’s metabolic activity. Oxidative stress is defined as a mismatch between the body’s ability to neutralise and eliminate reactive oxygen and nitrogen species (ROS and RNS). A determination of mitochondria failure in increasing oxidative stress, as well as its implications in neurodegenerative illnesses and apoptosis, is a significant developmental process of focus in this review. The neuroprotective effects of bioactive compounds linked to neuronal regulation, as well as related neuronal development abnormalities, will be investigated. In conclusion, the study of secondary components and the use of mitochondrial features in the analysis of various neurodevelopmental diseases has enabled the development of a new class of mitochondrial-targeted pharmaceuticals capable of alleviating neurodegenerative disease states and enabling longevity and healthy ageing for the vast majority of people

Characterization of Cell Death Induced by Imine Analogs of Trans-Resveratrol: Induction of Mitochondrial Dysfunction and Overproduction of Reactive Oxygen Species Leading to, or Not, Apoptosis without the Increase in the S-Phase of the Cell Cycle

Trans-resveratrol (RSV) is a non-flavonoid polyphenol (stilbene) with numerous biological activities, such as anti-tumor activities. However, RSV is rapidly metabolized, which limits its therapeutic use. The availability of RSV analogues with similar activities for use in vivo is therefore a major challenge. For this purpose, several isomeric analogues of RSV, aza-stilbenes (AZA-ST 1a–g), were synthesized, and their toxicities were characterized and compared to those of RSV on murine N2a neuronal cells using especially flow cytometric methods. All AZA-ST 1a–g have an inhibitory concentration 50 (IC50) between 11.3 and 25 µM when determined by the crystal violet assay, while that of RSV is 14.5 µM. This led to the characterization of AZA-ST 1a–g—induced cell death, compared to RSV, using three concentrations encompassing the IC50s (6.25, 12.5 and 25 µM). For AZA-ST 1a–g and RSV, an increase in plasma membrane permeability to propidium iodide was observed, and the proportion of cells with depolarized mitochondria measured with DiOC6(3) was increased. An overproduction of reactive oxygen species (ROS) was also observed on whole cells and at the mitochondrial level using dihydroethidium and MitoSox Red, respectively. However, only RSV induced a mode of cell death by apoptosis associated with a marked increase in the proportion of cells with condensed and/or fragmented nuclei (12.5 µM: 22 ± 9%; 25 µM: 80 ± 10%) identified after staining with Hoechst 33342 and which are characteristic of apoptotic cells. With AZA-ST, a slight but significant increase in the percentage of apoptotic cells was only detected with AZA-ST 1b (25 µM: 17 ± 1%) and AZA-ST 1d (25 µM: 26 ± 4%). Furthermore, only RSV induced significant cell cycle modifications associated with an increase in the percentage of cells in the S phase. Thus, AZA-ST 1a–g—induced cell death is characterized by an alteration of the plasma membrane, an induction of mitochondrial depolarization (loss of ΔΨm), and an overproduction of ROS, which may or may not result in a weak induction of apoptosis without modification of the distribution of the cells in the different phases of the cell cycle

Cytoprotective effects of α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol on 7-ketocholesterol – Induced oxiapoptophagy: Major roles of PI3-K / PDK-1 / Akt signaling pathway and glutathione peroxidase activity in cell rescue

On murine N2a cells, 7-ketocholesterol induced an oxiapotophagic mode of cell death characterized by oxidative stress (reactive oxygen species overproduction on whole cells and at the mitochondrial level; lipid peroxidation), apoptosis induction (caspase-9, −3 and −7 cleavage, PARP degradation) and autophagy (increased ratio LC3-II / LC3-I). Oxidative stress was strongly attenuated by diphenyleneiodonium chloride which inhibits NAD(P)H oxidase. Mitochondrial and peroxisomal morphological and functional changes were also observed. Down regulation of PDK1 / Akt signaling pathways as well as of GSK3 / Mcl-1 and Nrf2 pathways were simultaneously observed in 7-ketocholesterol-induced oxiapoptophagy. These events were prevented by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by LY-294002, a PI3-K inhibitor, demonstrated an essential role of PI3-K in cell rescue. The rupture of oxidative stress in 7-ketocholesterol-induced oxiapoptophagy was also associated with important modifications of glutathione peroxidase, superoxide dismutase and catalase activities as well as of glutathione peroxidase-1, superoxide dismutase-1 and catalase level and expression. These events were also counteracted by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol. The inhibition of the cytoprotection by mercaptosuccinic acid, a glutathione peroxidase inhibitor, showed an essential role of this enzyme in cell rescue. Altogether, our data support that the reactivation of PI3-K and glutathione peroxidase activities by α-linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, oleic acid and α-tocopherol are essential to prevent 7KC-induced oxiapoptophagy