Dalila Saidane-Mosbahi

Ischemic preconditioning reduces endoplasmic reticulum stress and upregulates hypoxia inducible factor-1α in ischemic kidney: the role of nitric oxide.

BackgroundAlthough recent studies indicate that renal ischemic preconditioning (IPC) protects the kidney from ischemia-reperfusion (I/R) injury, the precise protective mechanism remains unclear. In the current study, we investigated whether early IPC could upregulate hypoxia inducible transcription factor-1α (HIF-1α) expression and could reduce endoplasmic reticulum (ER) stress after renal I/R and whether pharmacological inhibition of nitric oxide (NO) production would abolish these protective effects.MethodsKidneys of Wistar rats were subjected to 60 min of warm ischemia followed by 120 min of reperfusion (I/R group), or to 2 preceding cycles of 5 min ischemia and 5 min reperfusion (IPC group), or to intravenously injection of NG-nitro-L-arginine methylester (L-NAME, 5 mg/kg) 5 min before IPC (L-NAME+IPC group). The results of these experimental groups were compared to those of a sham-operated group. Sodium reabsorption rate, creatinine clearance, plasma lactate dehydrogenase (LDH) activity, tissues concentrations of malonedialdehyde (MDA), HIF-1α and nitrite/nitrate were determined. In addition, Western blot analyses were performed to identify the amounts of Akt, endothelial nitric oxide synthase (eNOS) and ER stress parameters.ResultsIPC decreased cytolysis, lipid peroxidation and improved renal function. Parallely, IPC enhanced Akt phosphorylation, eNOS, nitrite/nitrate and HIF-1α levels as compared to I/R group. Moreover, our results showed that IPC increased the relative amounts of glucose-regulated protein 78 (GRP78) and decreased those of RNA activated protein kinase (PKR)-like ER kinase (PERK), activating transcription factor 4 (ATF4) and TNF-receptor-associated factor 2 (TRAF2) as judged to I/R group. However, pre treatment with L-NAME abolished these beneficial effects of IPC against renal I/R insults.ConclusionThese findings suggest that early IPC protects kidney against renal I/R injury via reducing oxidative and ER stresses. These effects are associated with phosphorylation of Akt, eNOS activation and NO production contributing thus to HIF-1α stabilization. The beneficial impact of IPC was abolished when NO production is inhibited before IPC application.

Candida famata modulates toll‐like receptor, β‐defensin, and proinflammatory cytokine expression by normal human epithelial cells

Candida albicans is no longer the only yeast involved in infectious disorders, as others, such as C. famata, commonly associated with foods as well as terrestrial and marine environments, are being recognized as potential emerging pathogens that cause human candidiasis. We investigated the interaction between C. famata and human epithelial cells using monolayer cultures and an engineered human oral mucosa (EHOM). C. famata was able to adhere to gingival epithelial cells but failed to adopt the hyphal form in the presence/absence of proteins. Interestingly, when cultured onto the engineered human oral mucosa (EHOM), C. famata formed a biofilm and invaded the connective tissue. When normal human gingival epithelial cells were put in contact with C. famata, they expressed high levels of Toll‐like receptors (TLR)‐2, ‐4, and ‐6, but not TLR‐9 mARN. The upregulation of TLRs was paralleled by an increase of IL‐1β and TNFα, but not IFNγ mARN expression, suggesting the involvement of specific pro‐inflammatory cytokines (IL‐1β and TNFα) in the defense against infection with C. famata. The active role of epithelial cells in the innate immunity against C. famata infection was enhanced by their capacity to express high levels of human β‐defensin (HBD)‐1, ‐2, and ‐3. The upregulation of pro‐inflammatory cytokines and antimicrobial peptide expression may explain the growth inhibition of C. famata by the gingival epithelial cells. Overall results provide additional evidence of the involvement of C. famata in the activation of innate immunity and the contribution of human epithelial cells in local defenses against such exogenous stimulations as C. famata infections. J. Cell. Physiol. 222:209–218, 2010.

Attenuation of endoplasmic reticulum stress and mitochondrial injury in kidney with ischemic postconditioning application and trimetazidine treatment

BackgroundEndoplasmic reticulum (ER) and mitochondria have been implicated in the pathology of renal ischemia/reperfusion (I/R). In the present study, we investigated whether the use of ischemic postconditioning (IPostC) and trimetazidine (TMZ) separately or combined could reduce ER stress and mitochondria damage after renal ischemia.MethodsKidneys of Wistar rats were subjected to 60-min of warm ischemia followed by 120-min of reperfusion (I/R group, n = 6), or to 6 cycles of ischemia/reperfusion (10-s each cycle) just after 60-min of warm ischemia (IPostC group, n = 6), or to i.p. injection of TMZ (3 mg/kg) 30-min before ischemia (TMZ group, n = 6), or to the combination of both treatments (IPostC+TMZ group, n = 6). The results of these experimental groups were compared to those of a sham-operated group in which rat renal pedicles were only dissected. Sodium reabsorption rate, creatinine clearance lactate deshydrogenase (LDH) activity in plasma, and concentration of malonedialdehyde (MDA) in tissue were determined. In addition, Western blot analysis was performed to identify the amounts of cytochrome c, c-JunNH2-terminal kinase (JNK), voltage-dependent anion channel (VDAC), glycogen synthase kinase 3-beta (GSK3-β), and ER stress parameters.ResultsIPostC or/and TMZ significantly decreased cytolysis, oxidative stress and improved renal function in comparison to I/R group. IPostC but not TMZ significantly attenuated ER stress parameters versus I/R group. Indeed, it down-regulated the glucose-regulated protein 78 (GRP78), the activating transcription factor 4 (ATF4), the RNA activated protein kinase (PKR)-like ER kinas (PERK), the X box binding protein-1 (XBP-1) and the caspase12 protein levels. TMZ treatment significantly augmented GSK3-β phosphorylation and reduced levels of cytochrome c and VDAC phosphorylation in comparison to IPostC application. The combination of both treatments gave a synergetic effect. It significantly improved the survival rate, attenuated cytolysis, oxidative stress and improved renal function.ConclusionThis study revealed that IPostC protects kidney from I/R injury by suppressing ER stress while the beneficial effects of TMZ are mediated by mitochondria protection. The combination of both treatments ameliorated functional recovery.

Normal Human Gingival Epithelial Cells Sense C. parapsilosis by Toll-Like Receptors and Module Its Pathogenesis through Antimicrobial Peptides and Proinflammatory Cytokines

This study was designed to investigate the interaction between C. parapsilosis and human epithelial cells using monolayer cultures and an engineered human oral mucosa (EHOM). C. parapsilosis was able to adhere to gingival epithelial cells and to adopt the hyphal form in the presence of serum. Interestingly, when cultured onto the engineered human oral mucosa (EHOM), C. parapsilosis formed small biofilm and invaded the connective tissue. Following contact with C. parapsilosis, normal human gingival epithelial cells expressed high levels of Toll-like receptors (TLR)-2, -4, and -6, but not TLR-9 mRNA. The upregulation of TLRs was paralleled by an increase of IL-1β, TNFα, and IFNγ mRNA expression, suggesting the involvement of these cytokines in the defense against infection with C. parapsilosis. The active role of epithelial cells in the innate immunity against C. parapsilosis infection was enhanced by their capacity to express high levels of human beta-defensin-1, -2, and -3. The upregulation of proinflammatory cytokines and antimicrobial peptide expression may explain the growth inhibition of C. parapsilosis by the gingival epithelial cells. Overall results provide additional evidence of the involvement of epithelial cells in the innate immunity against C. parapsilosis infections.

Relevance of Epidermal Growth Factor to Improve Steatotic Liver Preservation in IGL-1 Solution

AIM Static preservation solution is critical for liver graft outcomes, especially when steatosis is present. Institut Georges Lopez (IGL)-1 solution protects fatty livers effectively against cold ischemia reperfusion injury. Its benefits are mediated by nitric oxide and prevention of oxidative stress. The supplementation of IGL-1 with epidermal growth factor (EGF) enhances steatotic graft preservation by increasing adenosine triphosphate content, thereby mitigating oxidative stress and mitochondrial damage. METHODS After steatotic livers were preserved for 24 hours in IGL-1 solution with or without EGF supplements, they were perfused ex vivo for 2 hours at 37°C. The benefits of EGF were assessed by evidences of hepatic damage and function--transaminases, bile production, and flow rate--as well as by other factors presumably associated with the poor tolerance of fatty livers toward cold ischemia-reperfusion injury (IRI)--energy metabolism, mitochondrial damage, oxidative stress, eNOS activity and proinflammatory interleukin (IL) beta content. RESULTS Steatotic livers preserved in IGL-1 solutions supplemented with EGF (10 μg/L) showed lower transaminase levels, greater bile production, and ameliorated flow rates when compared to IGL-1 alone. In addition, energy metabolism deterioration, mitochondrial damage, oxidative stress, and cytokine IL-1 beta release were prevented. CONCLUSION EGF addition to IGL-1 increased fatty liver graft preservation, thereby reducing steatotic liver damage against cold IRI.

Distribution and Sources of Polycyclic Aromatic Hydrocarbons Around a Petroleum Refinery Rejection Area in Jarzouna-Bizerte (Coastal Tunisia)

Polycyclic aromatic hydrocarbons in the refinery rejection area of STIR, Tunisias unique oil refinery located on the Jarzouna coast, were investigated. Two depth layers from three sites beside the refinery and one site some distance away from it were considered. The total concentration of 17 PAHs ranged from 916.42 ± 0.012 ng/g to 3146.2 ± 0.151 ng/g in Layer-I and from 962 ± 0.003 ng/g to 4541.1 ± 0.009 ng/g in Layer-II. The PAH profiles showed that the 4–5-ring compounds were the major PAHs detected in most sampling sites. Characteristic ratios of anthracene (Anth)/(Anth + phenanthrene (Phe)), and fluoranthene (Flu)/(Flu + pyrene (Pyr)) indicated that the PAH pollutants could originate from petrogenic and pyrolytic sources. Overall, our results indicate moderate contamination of the Jarzouna sediments with PAHs. However, even at moderate levels, PAHs levels in this marine environment must be controlled and reduced due to their possible side-effects on the ecosystems and human safety.

Cytokine release and cytotoxicity in human keratinocytes induced by polycyclic aromatic hydrocarbons (1-methylpyrene and perylene).

The cytotoxic effects of two polycyclic aromatic hydrocarbons (PAH) (1-methyplyrene and perylene) were investigated on human skin keratinocytes. Normal human keratinocytes were cultured in the presence of various concentrations of 1-methylpyrene and perylene either alone or in combination. Following incubation, keratinocyte adhesion, viability, proliferation, colony-forming efficiency, and apoptosis/necrosis level were examined. The effects of PAH on wound healing were also determined in vitro using a scrape-wound healing assay on epidermis-like tissue. In addition, the inflammatory cell response to PAH insult was examined through interleukin-1 (IL-1) α and interleukin-6 (IL-6) secretion. Each individual PAH significantly decreased keratinocyte adhesion and viability in a concentration-dependent manner, which was associated with a reduced ability of keratinocytes to proliferate and form colonies. When PAH were combined, a greater effect on keratinocyte adhesion, viability, and proliferation was noted. Decreased cell proliferation/colony-forming efficiency was accompanied by increased cell apoptosis following incubation with either PAH. This effect was enhanced by the inhibitory influence on keratinocyte migration, as assessed by culture scratching. Each PAH also exerted a significant effect on keratinocyte immune functions by modulating the secretion of inflammatory mediators. Indeed, 1-methylpyrene or perylene, individually or when combined, significantly upregulated IL-1α and IL-6 secretion. This effect was greater and was concentration dependent when the PAH combination was used. Overall results indicate that 1-methylpyrene and perylene exerted a cytotoxic effect on human keratinocytes. Our findings may shed light on mechanisms underlying potential adverse effects of 1-methylpyrene and perylene on human skin.

Effet du pré-conditionnement ischémique et de la vitamine C sur la reprise fonctionnelle des reins ischémiques

Resume But Presenter les resultats du pre-conditionnement ischemique (PCI), du pre-conditionnement pharmacologique induit par la vitamine C (Vit C) et de l’association des deux conditionnements sur la reprise fonctionnelle des reins de rats apres une ischemie chaude prolongee. Materiel Nous avons utilise 46 rats repartis en 5 groupes experimentaux. Les reins du groupe sham (n=9) subissent uniquement une dissection du pedicule. L’ischemie (60 min, n=10) est induite par le clampage des deux reins. Le PCI (n=9) consiste en deux cycles successifs (5 min15 min) d’ischemie/reperfusion (IR). La Vit C (100 mg/Kg, n=9) est administree par voie intraveineuse 30 min avant 1’1 chaude. Le groupe Vit C+PCI (n=9) est I’association des deux traitements. La malonedialdehyde (MDA) tissulaire, la lactate deshydrogenase (LDH) plasmatique, le taux de reabsorption de sodium (TRNa) et la clairance de la creatinine (DFG) sont evalues apres 120 min de reperfusion des reins. Resultats Les reins ischemiques montrent une augmentation significative des concentrations de MDA et de LDH et une diminution significative du DFG et du TRNa, par comparaison au groupe sham. L’utilisation du PCI ou de la Vit C entraine une amelioration significative de la fonction renale, par rapport au groupe ischemie. L’association Vit C+PCI montre une legere amelioration des parametres experimentaux par rapport a ceux du groupe ischemie, mais n’ameliore pas le fonctionnement des reins par rapport a une utilisation separee du PCI ou de la Vit C. Conclusion Le PCI et la Vit C ameliorent les parametres fonctionnels des reins ischemiques. Cependant, les effets protecteurs sont attenues lorsque les deux traitements sont associes.

Crude Oil Metagenomics for Better Bioremediation of Contaminated Environments

Our planet suffers more and more from various pollution problems. The marine environments are always regarded as sewers without end and are then subjected to different types of toxic rich rejects leading to oceans and seas degradation. The marine environment becomes at the same time the witness and the actor of the history of the planet, and its chemical composition witnesses all the complexity of its evolution. Coastal regions are often where we find various pollutants. Seawater (Jaffrennou et al. 2007; Perez-Carrera et al. 2007), marine sediments (Wakeham, 1996), and interstitial water (Perez-Carrera et al., 2007) have shown this pollution. Petroleum hydrocarbons are among the most toxic compounds poured at sea. Known as the most significant pollutant, crude oil can persist for years (Burns & Teal 1979), with dangerous effects on coastal environments and negative effects on both the ecosystem and the marine biodiversity (Clark 1992; Rice et al., 1996). In marine environment, crude oil is subjected to physico-chemical and biological modifications, which enhance hydrocarbons solubility in the water and consequentially cause extensive damage to marine life, natural resources, and human health.

ISCHEMIC POST-CONDITIONING PROTECTS KIDNEY FROM ISCHEMIA/REPERFUSION INJURY THROUGH ATTENUATION OF ENDOPLASMIC RETICULUM STRESS: 1361

A. Mahfoudh-Boussaid1, M.A. Zaouali2, J. Rosello-catafau3, D. Saidane-Mosbahi4, A. Miled5, S. Ghoul-Mezgar6, H. Ben Abdennebi7 1, Faculty of pharmacy, Monastir/TUNISIA, 2Experimental Pathology, IIBB-CSIC, Barcelona/SPAIN, 3, Unitat de Transplantament de fetge i viabilitat de l’empelt, Institut d ́Investigacions Biomèdiques August Pi i Sunyer-CIBERehd, barcelona/SPAIN, 4Human Physiology, Faculty of pharmacy, Monastir/TUNISIA, 5Biochemistry, Faculty of pharmacy, Monastir/TUNISIA, 6Histology, Faculty of pharmacy, Monastir/ TUNISIA, 7Humane Physiology, Faculty of pharmacy, Monastir/ TUNISIA