scholarly journals Tempol Alleviates Chronic Intermittent Hypoxia-Induced Pancreatic Injury Through Repressing Inflammation and Apoptosis

2019 ◽  
pp. 445-455
Author(s):  
Y. WANG ◽  
L. AI ◽  
B. HAI ◽  
Y. CAO ◽  
R. LI ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Pancreatic Injury ◽  
Protective Role ◽  
Pancreatic Tissue ◽  
Mitogen Activated Protein Kinase ◽  
Chronic Intermittent Hypoxia ◽  
Obstructive Sleep ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis ◽  
Oxide Synthase

Obstructive sleep apnea (OSA) has been demonstrated to be implicated in disorder of insulin secretion and diabetes mellitus. In this study, we aimed to evaluate the protective role of tempol, a powerful antioxidant, in chronic intermittent hypoxia (IH)-induced pancreatic injury. The rat model of OSA was established by IH exposure. The pathological changes, increased blood-glucose level, and raised proinsulin/insulin ratio in pancreatic tissues of rats received IH were effectively relieved by tempol delivery. In addition, the enhanced levels of pro-inflammatory cytokines, TNF-α, IL-1β, IL-6, and inflammatory mediators, PGE2, cyclooxygenase-2 (COX-2), NO, and inducible nitric oxide synthase (iNOS) in pancreatic tissue were suppressed by tempol. Moreover, tempol inhibited IH-induced apoptosis in pancreatic tissue as evidenced by upregulated Bcl-2 level, and downregulated Bax and cleaved caspase-3 levels. Finally, the abnormal activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways induced by IH was restrained by tempol administration. In summary, our study demonstrates that tempol relieves IH-induced pancreatic injury by inhibiting inflammatory response and apoptosis, which provides theoretical basis for tempol as an effective treatment for OSA-induced pancreatic injury.

scholarly journals Uncoupling of Vascular Nitric Oxide Synthase Caused by Intermittent Hypoxia

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad Badran ◽  
Bisher Abuyassin ◽  
Saeid Golbidi ◽  
Najib Ayas ◽  
Ismail Laher
Keyword(s):  
Nitric Oxide ◽  
Endothelial Dysfunction ◽  
Intermittent Hypoxia ◽  
Asymmetric Dimethylarginine ◽  
Chronic Intermittent Hypoxia ◽  
No Production ◽  
Diabetic Mice ◽  
Enos Uncoupling ◽  
Obstructive Sleep ◽  
Oxide Synthase

Objective. Obstructive sleep apnea (OSA), characterized by chronic intermittent hypoxia (CIH), is often present in diabetic (DB) patients. Both conditions are associated with endothelial dysfunction and cardiovascular disease. We hypothesized that diabetic endothelial dysfunction is further compromised by CIH.Methods. Adult male diabetic (BKS.Cg-Dock7m+/+Leprdb/J) (db/db) mice (10 weeks old) and their heterozygote littermates were subjected to CIH or intermittent air (IA) for 8 weeks. Mice were separated into 4 groups: IA (intermittent air nondiabetic), IH (intermittent hypoxia nondiabetic), IADB (intermittent air diabetic), and IHDB (intermittent hypoxia diabetic) groups. Endothelium-dependent and endothelium-independent relaxation and modulation by basal nitric oxide (NO) were analyzed using wire myograph. Plasma 8-isoprostane, interleukin-6 (IL-6), and asymmetric dimethylarginine (ADMA) were measured using ELISA. Uncoupling of eNOS was measured using dihydroethidium (DHE) staining.Results. Endothelium-dependent vasodilation and basal NO production were significantly impaired in the IH and IADB group compared to IA group but was more pronounced in IHDB group. Levels of 8-isoprostane, IL-6, ADMA, and eNOS uncoupling were ≈2-fold higher in IH and IADB groups and were further increased in the IHDB group.Conclusion. Endothelial dysfunction is more pronounced in diabetic mice subjected to CIH compared to diabetic or CIH mice alone. Oxidative stress, ADMA, and eNOS uncoupling were exacerbated by CIH in diabetic mice.

scholarly journals A Protective Role of SOD1 Overexpression in Central Mediation of Bradycardia Following Chronic Intermittent Hypoxia in Mice

2020 ◽  
Author(s):  
Jin Chen ◽  
He Gu ◽  
Robert D Wurster ◽  
Zixi Jack Cheng
Keyword(s):  
Transgenic Mice ◽  
Intermittent Hypoxia ◽  
Baroreflex Sensitivity ◽  
Cardiovascular Complications ◽  
Protective Role ◽  
Chronic Intermittent Hypoxia ◽  
Wild Type ◽  
Baroreflex Control ◽  
Aortic Depressor Nerve ◽  
Obstructive Sleep

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that is associated with many cardiovascular complications. Similar to OSA, chronic intermittent hypoxia (CIH) (a model for OSA) leads to oxidative stress and impairs baroreflex control of the heart rate (HR) in rodents. The baroreflex arc includes the aortic depressor nerve (ADN), vagal efferent, and central neurons. In this study, we used mice as a model to examine the effects of CIH on baroreflex sensitivity, aortic baroreceptor afferents and central and vagal efferent components of the baroreflex circuitry. Furthermore, we tested whether human Cu/Zn Superoxide Dismutase (SOD1) overexpression in the transgenic mice offers protection against CIH induced deficit of the baroreflex arc. Wild-type C57BL/6J and SOD1 mice were exposed to room air (RA) or CIH and were then anesthetized, ventilated and catheterized for measurement of mean arterial pressure (MAP) and HR. Compared with wild-type RA control, CIH impaired baroreflex sensitivity but increased maximum baroreceptor gain and the bradycardic response to vagal efferent stimulation. Additionally, CIH reduced the bradycardic response to ADN stimulation, indicating a diminished central regulation of bradycardia. Interestingly, SOD1 overexpression prevented CIH-induced attenuation of HR responses to ADN stimulation and preserved HR responses to vagal efferent stimulation in transgenic mice. We suggest that CIH decreased central mediation of the baroreflex and SOD1 overexpression may prevent the CIH-induced central deficit.

scholarly journals Protective Role of Raf-1 in Salmonella-Induced Macrophage Apoptosis

2001 ◽  
Vol 193 (3) ◽  
pp. 353-364 ◽  
Author(s):  
Veronika Jesenberger ◽  
Katarzyna J. Procyk ◽  
Jochen Rüth ◽  
Martin Schreiber ◽  
Hans-Christian Theussl ◽  
...  
Keyword(s):  
Proteasome Inhibitors ◽  
Nuclear Factor Κb ◽  
Protective Role ◽  
Mitogen Activated Protein Kinase ◽  
Caspase 1 ◽  
Extracellular Signal ◽  
Macrophage Apoptosis ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis

Invasive Salmonella induces macrophage apoptosis via the activation of caspase-1 by the bacterial protein SipB. Here we show that infection of macrophages with Salmonella causes the activation and degradation of Raf-1, an important intermediate in macrophage proliferation and activation. Raf-1 degradation is SipB- and caspase-1–dependent, and is prevented by proteasome inhibitors. To study the functional significance of Raf-1 in this process, the c-raf-1 gene was inactivated by Cre-loxP–mediated recombination in vivo. Macrophages lacking c-raf-1 are hypersensitive towards pathogen-induced apoptosis. Surprisingly, activation of the antiapoptotic mitogen-activated protein kinase kinase (MEK)/extracellular signal–regulated kinase (ERK) and nuclear factor κB pathways is normal in Raf-1–deficient macrophages, and mitochondrial fragility is not increased. Instead, pathogen-mediated activation of caspase-1 is enhanced selectively, implying that Raf-1 antagonizes stimulus-induced caspase-1 activation and apoptosis.

scholarly journals Zamzam water protects cancer cells from chemotherapy-induced apoptosis via mitogen-activated protein kinase-dependent pathway

2019 ◽  
Vol 118 ◽  
pp. 109376
Author(s):  
Abdul Khalid Siraj ◽  
Rafia Begum ◽  
Roxanne Melosantos ◽  
Wafaa Albalawy ◽  
Jehan Abboud ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cancer Cells ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis ◽  
Dependent Pathway

scholarly journals UVB-mediated activation of p38 mitogen-activated protein kinase enhances resistance of normal human keratinocytes to apoptosis by stabilizing cytoplasmic p53

2002 ◽  
Vol 365 (1) ◽  
pp. 133-145 ◽  
Author(s):  
Nadine CHOUINARD ◽  
Kristoffer VALERIE ◽  
Mahmoud ROUABHIA ◽  
Jacques HUOT
Keyword(s):  
Adaptive Response ◽  
Human Keratinocytes ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Dominant Negative Mutant ◽  
Normal Human Keratinocytes ◽  
Mitogen Activated Protein ◽  
Normal Human ◽  
Induced Apoptosis ◽  
Negative Mutant

Human keratinocytes respond to UV rays by developing a fast adaptive response that contributes to maintaining their functions and survival. We investigated the role of the mitogen-activated protein kinase pathways in transducing the UV signals in normal human keratinocytes. We found that UVA, UVB or UVC induced a marked and persistent activation of p38, whereas c-Jun N-terminal kinase or extracellular signal-regulated kinase were less or not activated respectively. Inhibition of p38 activity by expression of a dominant-negative mutant of p38 or with SB203580 impaired cell viability and led to an increase in UVB-induced apoptosis. This sensitization to apoptosis was independent of caspase activities. Inhibition of p38 did not sensitize transformed HaCaT keratinocytes to UVB-induced apoptosis. In normal keratinocytes, expression of a dominant-negative mutant of p53 increased UVB-induced cell death, pointing to a role for p53. In these cells, UVB triggered a p38-dependent phosphorylation of p53 on Ser-15. This phosphorylation was associated with an SB203580-sensitive accumulation of p53, even in the presence of a serine phosphatase inhibitor. Accumulated p53 was localized mainly in the cytoplasm, independently of CRM1 nuclear export. In HaCaT cells, p53 was localized exclusively in the nucleus and its distribution and level were not affected by UVB or p38 inhibition. However, UVB induced an SB203580-insensitive phosphorylation on Ser-15 of mutated p53. Overall, our results suggest that, in normal human keratinocytes, protection against UVB depends on p38-mediated phosphorylation and stabilization of p53 and is tightly associated with the cytoplasmic sequestration of wild-type p53. We conclude that the p38/p53 pathway plays a key role in the adaptive response of normal human keratinocytes against UV stress.

MKK3-p38 signaling promotes apoptosis and the early inflammatory response in the obstructed mouse kidney

2007 ◽  
Vol 293 (5) ◽  
pp. F1556-F1563 ◽  
Author(s):  
Frank Y. Ma ◽  
Greg H. Tesch ◽  
Richard A. Flavell ◽  
Roger J. Davis ◽  
David J. Nikolic-Paterson
Keyword(s):  
Inflammatory Response ◽  
P38 Mapk ◽  
Renal Injury ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Mrna Levels ◽  
Direct Role ◽  
Mitogen Activated Protein ◽  
Early Inflammatory Response ◽  
Induced Apoptosis

Activation of the p38 mitogen-activated protein kinase (MAPK) pathway induces inflammation, apoptosis, and fibrosis. However, little is known of the contribution of the upstream kinases, MMK3 and MKK6, to activation of the p38 kinase in the kidney and consequent renal injury. This study investigated the contribution of MKK3 to p38 MAPK activation and renal injury in the obstructed kidney. Groups of eight wild-type (WT) or Mkk3−/− mice underwent unilateral ureteric obstruction (UUO) and were killed 3 or 7 days later. Western blotting showed a marked increase in phospho-p38 (p-p38) MAPK in UUO WT kidney. The same trend of increased p-p38 MAPK was seen in the UUO Mkk3−/− kidney, although the actual level of p-p38 MAPK was significantly reduced compared with WT, and this could not be entirely compensated for by the increase in MKK6 expression in the Mkk3−/− kidney. Apoptosis of tubular and interstitial cells in WT UUO mice was reduced by 50% in Mkk3−/− UUO mice. Furthermore, cultured Mkk3−/− tubular epithelial cells showed resistance to H2O2-induced apoptosis, suggesting a direct role for MKK3-p38 signaling in tubular apoptosis. Upregulation of MCP-1 mRNA levels and macrophage infiltration seen on day 3 in WT UUO mice was significantly reduced in Mkk3−/− mice, but this difference was not evident by day 7. The development of renal fibrosis in Mkk3−/− UUO mice was not different from that seen in WT UUO mice. In conclusion, these studies identify discrete roles for MKK3-p38 signaling in renal cell apoptosis and the early inflammatory response in the obstructed kidney.

scholarly journals Regulation of p73-mediated apoptosis by c-Jun N-terminal kinase

2007 ◽  
Vol 405 (3) ◽  
pp. 617-623 ◽  
Author(s):  
Emma V. Jones ◽  
Mark J. Dickman ◽  
Alan J. Whitmarsh
Keyword(s):  
Dna Damage ◽  
Stress Responses ◽  
Tumour Progression ◽  
Chemotherapeutic Agents ◽  
Signalling Pathway ◽  
Mitogen Activated Protein Kinase ◽  
P53 Family ◽  
Jnk Pathway ◽  
Mitogen Activated Protein ◽  
Induced Apoptosis

The JNK (c-Jun N-terminal kinase)/mitogen-activated protein kinase signalling pathway is a major mediator of stress responses in cells, including the response to DNA damage. DNA damage also causes the stabilization and activation of p73, a member of the p53 family of transcription factors. p73, like p53, can mediate apoptosis by up-regulating the expression of pro-apoptotic genes, including Bax (Bcl2-associated X protein) and PUMA (p53 up-regulated modulator of apoptosis). Changes in p73 expression have been linked to tumour progression, particularly in neuroblastomas, whereas in tumours that feature inactivated p53 there is evidence that p73 may mediate the apoptotic response to chemotherapeutic agents. In the present study, we demonstrate a novel link between the JNK signalling pathway and p73. We use pharmacological and genetic approaches to show that JNK is required for p73-mediated apoptosis induced by the DNA damaging agent cisplatin. JNK forms a complex with p73 and phosphorylates it at several serine and threonine residues. The mutation of JNK phosphorylation sites in p73 abrogates cisplatin-induced stabilization of p73 protein, leading to a reduction in p73 transcriptional activity and reduced p73-mediated apoptosis. Our results demonstrate that the JNK pathway is an important regulator of DNA damage-induced apoptosis mediated by p73.

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