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- Ghavami, Saeid, et al.
(författare)
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Airway mesenchymal cell death by mevalonate cascade inhibition : integration of autophagy, unfolded protein response and apoptosis focusing on Bcl2 family proteins
- 2014
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Ingår i: Biochimica et Biophysica Acta. Molecular Cell Research. - : Elsevier. - 0167-4889 .- 1879-2596. ; 1843:7, s. 1259-1271
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Tidskriftsartikel (refereegranskat)abstract
- HMG-CoA reductase, the proximal rate-limiting enzyme in the mevalonate pathway, is inhibited by statins. Beyond their cholesterol lowering impact, statins have pleiotropic effects and their use is linked to improved lung health. We have shown that mevalonate cascade inhibition induces apoptosis and autophagy in cultured human airway mesenchymal cells. Here, we show that simvastatin also induces endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in these cells. We tested whether coordination of ER stress, autophagy and apoptosis determines survival or demise of human lung mesenchymal cells exposed to statin. We observed that simvastatin exposure activates UPR (activated transcription factor 4, activated transcription factor 6 and IRE1 alpha) and caspase-4 in primary human airway fibroblasts and smooth muscle cells. Exogenous mevalonate inhibited apoptosis, autophagy and UPR, but exogenous cholesterol was without impact, indicating that sterol intermediates are involved with mechanisms mediating statin effects. Caspase-4 inhibition decreased simvastatin-induced apoptosis, whereas inhibition of autophagy by ATG7 or ATG3 knockdown significantly increased cell death. In BAX(-/-)/BAIC(-/) murine embryonic fibroblasts, simvastatin-triggered apoptotic and UPR events were abrogated, but autophagy flux was increased leading to cell death via necrosis. Our data indicate that mevalonate cascade inhibition, likely associated with depletion of sterol intermediates, can lead to cell death via coordinated apoptosis, autophagy, and ER stress. The interplay between these pathways appears to be principally regulated by autophagy and Bcl-2-family pro-apoptotic proteins. These findings uncover multiple mechanisms of action of statins that could contribute to refining the use of such agent in treatment of lung disease.
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| 2. |
- Ghavami, Saeid, et al.
(författare)
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Mevalonate Cascade Regulation of Airway Mesenchymal Cell Autophagy and Apoptosis: A Dual Role for p53
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:1, s. 0016523-
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Tidskriftsartikel (refereegranskat)abstract
- Statins inhibit the proximal steps of cholesterol biosynthesis, and are linked to health benefits in various conditions, including cancer and lung disease. We have previously investigated apoptotic pathways triggered by statins in airway mesenchymal cells, and identified reduced prenylation of small GTPases as a primary effector mechanism leading to p53-mediated cell death. Here, we extend our studies of statin-induced cell death by assessing endpoints of both apoptosis and autophagy, and investigating their interplay and coincident regulation. Using primary cultured human airway smooth muscle (HASM) and human airway fibroblasts (HAF), autophagy, and autophagosome formation and flux were assessed by transmission electron microscopy, cytochemistry (lysosome number and co-localization with LC3) and immunoblotting (LC3 lipidation and Atg 12-5 complex formation). Chemical inhibition of autophagy increased simvastatin-induced caspase activation and cell death. Similarly, Atg5 silencing with shRNA, thus preventing Atg5-12 complex formation, increased proapoptotic effects of simvastatin. Simvastatin concomitantly increased p53-dependent expression of p53 up-regulated modulator of apoptosis (PUMA), NOXA, and damage-regulated autophagy modulator (DRAM). Notably both mevalonate cascade inhibition-induced autophagy and apoptosis were p53 dependent: simvastatin increased nuclear p53 accumulation, and both cyclic pifithrin-alpha and p53 shRNAi partially inhibited NOXA, PUMA expression and caspase-3/7 cleavage (apoptosis) and DRAM expression, Atg5-12 complex formation, LC3 lipidation, and autophagosome formation (autophagy). Furthermore, the autophagy response is induced rapidly, significantly delaying apoptosis, suggesting the existence of a temporally coordinated p53 regulation network. These findings are relevant for the development of statin-based therapeutic approaches in obstructive airway disease.
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| 3. |
- Ghavami, Saeid, et al.
(författare)
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Statin-triggered cell death in primary human lung mesenchyrnal cells involves p53-PUMA and release of Smac and Omi but not cytochrome c
- 2010
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier. - 0006-3002 .- 1878-2434. ; 1803:4, s. 452-467
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Tidskriftsartikel (refereegranskat)abstract
- Statins inhibit 3-hydroxy-3-methyl-glutarylcoenzyme CoA (HMG-CoA) reductase, the proximal enzyme forcholesterol biosynthesis. They exhibit pleiotropic effects and are linked to health benefits for diseasesincluding cancer and lung disease. Understanding their mechanism of action could point to new therapies,thus we investigated the response of primary cultured human airway mesenchymal cells, which play aneffector role in asthma and chronic obstructive lung disease (COPD), to simvastatin exposure. Simvastatininduced apoptosis involving caspase-9, -3 and -7, but not caspase-8 in airway smooth muscle cells andfibroblasts. HMG-CoA inhibition did not alter cellular cholesterol content but did abrogate de novocholesterol synthesis. Pro-apoptotic effects were prevented by exogenous mevalonate, geranylgeranylpyrophosphate and farnesyl pyrophosphate, downstream products of HMG-CoA. Simvastatin increasedexpression of Bax, oligomerization of Bax and Bak, and expression of BH3-only p53-dependent genes, PUMAand NOXA. Inhibition of p53 and silencing of p53 unregulated modulator of apoptosis (PUMA) expressionpartly counteracted simvastatin-induced cell death, suggesting a role for p53-independent mechanisms.Simvastatin did not induce mitochondrial release of cytochrome c, but did promote release of inhibitor ofapoptosis (IAP) proteins, Smac and Omi. Simvastatin also inhibited mitochondrial fission with the loss ofmitochondrial Drp1, an essential component of mitochondrial fission machinery. Thus, simvastatin activatesnovel apoptosis pathways in lung mesenchymal cells involving p53, IAP inhibitor release, and disruption ofmitochondrial fission.
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| 4. |
- Laux, Timothy S, et al.
(författare)
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Nicaragua revisited : evidence of lower prevalence of chronic kidney disease in a high-altitude, coffee-growing village
- 2012
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Ingår i: JN. Journal of Nephrology (Milano. 1992). - : SAGE Publications. - 1121-8428 .- 1724-6059. ; 25:4, s. 533-540
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chronic kidney disease (CKD) is found at epidemic levels in certain populations of the Pacific Coast in northwestern Nicaragua especially in younger men. There are knowledge gaps concerning CKD's prevalence in regions at higher altitudes.METHODS: A cross-sectional study of adults between the ages of 20 and 60 years in 1 coffee-growing village in Nicaragua located at 1,000 m above sea level (MASL) altitude was performed. Predictors included participant sex, age, occupation, conventional CKD risk factors and other factors associated with CKD suggested by previous surveys in Central America. Outcomes included serum creatinine (SCr) values >1.2 mg/dL for men and >0.9 mg/dL for women, estimated glomerular filtration rate (GFR) <60 ml/min per 1.73 m2, dipstick proteinuria stratified as microalbuminuria (30-300 mg/dL) and macroalbuminuria (>300 mg/dL), hypertension and body mass index.RESULTS: Of 324 eligible participants, 293 were interviewed (90.4%), and 267 of those received the physical exam (82.4% overall). Of the sample, 45% were men. Prevalence rate of estimated GFR <60 ml/min per 1.73 m2 was 0 for men (0%) and 2 for women (1.4%). The prevalence of at least microalbuminuria was significantly higher among men compared with women (27.5% vs. 21.4%, respectively; p=0.02).CONCLUSIONS: The CKD prevalence in this village is comparable to a previously studied Nicaraguan coffee-farming region and much lower than previously screened portions of northwestern Nicaragua. There is heterogeneity in CKD prevalence across Nicaragua. At this time, screenings should target individuals living in previously identified, higher risk regions. More work is needed to understand determinants of CKD in this resource-poor nation.
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| 5. |
- Laux, Timothy S., et al.
(författare)
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Revalence of hypertension and associated risk factors in six nicaraguan communities
- 2012
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Ingår i: Ethnicity & Disease. - 1049-510X. ; 22:2, s. 129-135
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Describe the prevalence of hypertension. Design: Population based cross-sectional survey. Setting: Six Nicaraguan communities with varying economies. Participants: 1,355 adults aged 20-60 years who completed both self-reported and quantitative measures of health. Main Outcome Measures: Prevalence of hypertension (systolic >= 140 mm Hg, diastolic >= 90 mm Hg, or self-reported medical history with diagnosis by a health care professional), uncontrolled hypertension (systolic >= 140 mm Hg or diastolic >= 90 mm Hg), diabetes (urinary glucose excretion >= 100 mg/dL or self-reported medical history diagnosed by a health care professional), and uncontrolled diabetes (urinary glucose excretion >= 100 mg/dL only). Results: The prevalence of hypertension was 22.0% (19.2% in men, 24.2% in women). Blood pressure was controlled in 31.0% of male hypertensives and 55.1% of female hypertensives (odds ratio [OR] 2.86; 95% confidence interval [CI] 1.74-4.69). Older age and higher body mass index were strongly associated with hypertension. Women who completed primary school had a lower risk of hypertension (OR .40; 95% CI .19-.85) compared to those with no formal education. A history of living in both urban and rural settings was associated with lower prevalence of hypertension (OR .52; 95% CI .34-.79). Diabetes mellitus was found in 1.2% of men and 4.3% of women. Male sex was independently associated with decreased risk of diabetes (OR .31; 95% CI .11-.86). Conclusions: At least one cardiovascular risk factor was found in half of this Nicaraguan sample. Cardiovascular risk factors should be the target of educational efforts, screening, and treatment.
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| 6. |
- Ray, Nicholas E., et al.
(författare)
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A review of how we assess denitrification in oyster habitats and proposed guidelines for future studies
- 2021
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Ingår i: Limnology and Oceanography. - : Wiley. - 1541-5856. ; 19:10, s. 714-731
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Forskningsöversikt (refereegranskat)abstract
- Excess nitrogen (N) loading and resulting eutrophication plague coastal ecosystems globally. Much work is being done to remove N before it enters coastal receiving waters, yet these efforts are not enough. Novel techniques to remove N from within the coastal ecosystem are now being explored. One of these techniques involves using oysters and their habitats to remove N via denitrification. There is substantial interest in incorporating oyster-mediated enhancement of benthic denitrification into N management plans and trading schemes. Measuring denitrification, however, is expensive and time consuming. For large-scale adoption of oyster-mediated denitrification into nutrient management plans, we need an accurate model that can be applied across ecosystems. Despite significant effort to measure and report rates of denitrification in oyster habitats, we are unable to create such a model, due to methodological differences between studies, incomplete data reporting, and inconsistent measurements of environmental variables that may be used to predict denitrification. To make a model that can predict denitrification in oyster habitats a reality, a common sampling and reporting scheme is needed across studies. Here, we provide relevant background on how oysters may stimulate denitrification, and the importance of oyster-mediated denitrification in remediating excess N loading to coastal systems. We then summarize methods commonly used to measure denitrification in oyster habitats, discuss the importance of various environmental variables that may be useful for predicting denitrification, and present a set of guidelines for measuring denitrification in oyster habitats, allowing development of models to support incorporation of oyster-mediated denitrification into future policy decisions.
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