Mitochondrial oxidative stress. Physiologic consequences and potential for a role in aging

P-coumaric Acid: Advances in Pharmacological Research Based on Oxidative Stress

P-coumaric acid is an important phenolic compound that is mainly found in fruits, vegetables, grains, and fungi and is also abundant in Chinese herbal medicines. In this review, the pharmacological research progress of p-coumaric acid in recent years was reviewed, with emphasis on its role and mechanism in oxidative stress-related diseases, such as inflammation, cardiovascular diseases, diabetes, and nervous system diseases. Studies have shown that p-coumaric acid has a positive effect on the prevention and treatment of these diseases by inhibiting oxidative stress. In addition, p-coumaric acid also has anti-tumor, antibacterial, anti-aging skin and other pharmacological effects. This review will provide reference and inspiration for further research on the pharmacological effects of p-coumaric acid.

The intrinsic apoptotic pathway lies upstream of reactive species production in cortical neurons and age-related oxidative stress in the brain

A BAX- and mitochondria-dependent production of reactive oxygen species (ROS) and reactive species (reactive nitrogen species, RNS) lying downstream of these ROS occurs in apoptotic and nonapoptotic mouse sympathetic neurons and cerebellar granule cells in cell culture. These ROS have been shown to lie downstream of caspase 3 in mouse sympathetic neurons. Here we show that BAX is necessary for similar ROS production in apoptotic and nonapoptotic mouse cortical neurons in cell culture and that it also positively regulates oxidative stress in the brains of mice of different ages. Brains from mice with genetically reduced levels of mitochondrial superoxide dismutase 2 (SOD2) exhibited elevated levels of DNA strand breaks consistent with oxidative damage. Lipid peroxides were also elevated at some ages in comparison to the brains of wild type animals. BAX deletion in these mice reduced both brain DNA strand breaks and lipid peroxide levels to well below those of wild type animals. Deletion of caspase 3 greatly reduced age-augmented levels of brain oxidative stress markers including lipid peroxides, oxidized DNA, and nitrosylated proteins. These findings indicate that BAX contributes to ROS production in mouse cortical neurons, to oxidative stress their brains, and that this effect is likely mediated via caspase 3 activity.

Chronic inflammation and the hallmarks of aging

BACKGROUND

Recently, the hallmarks of aging were updated to include dysbiosis, disabled macroautophagy, and chronic inflammation. In particular, the low-grade chronic inflammation during aging, without overt infection, is defined as "inflammaging," which is associated with increased morbidity and mortality in the aging population. Emerging evidence suggests a bidirectional and cyclical relationship between chronic inflammation and the development of age-related conditions, such as cardiovascular diseases, neurodegeneration, cancer, and frailty. How the crosstalk between chronic inflammation and other hallmarks of aging underlies biological mechanisms of aging and age-related disease is thus of particular interest to the current geroscience research.

SCOPE OF REVIEW

This review integrates the cellular and molecular mechanisms of age-associated chronic inflammation with the other eleven hallmarks of aging. Extra discussion is dedicated to the hallmark of "altered nutrient sensing," given the scope of Molecular Metabolism. The deregulation of hallmark processes during aging disrupts the delicate balance between pro-inflammatory and anti-inflammatory signaling, leading to a persistent inflammatory state. The resultant chronic inflammation, in turn, further aggravates the dysfunction of each hallmark, thereby driving the progression of aging and age-related diseases.

MAIN CONCLUSIONS

The crosstalk between chronic inflammation and other hallmarks of aging results in a vicious cycle that exacerbates the decline in cellular functions and promotes aging. Understanding this complex interplay will provide new insights into the mechanisms of aging and the development of potential anti-aging interventions. Given their interconnectedness and ability to accentuate the primary elements of aging, drivers of chronic inflammation may be an ideal target with high translational potential to address the pathological conditions associated with aging.

Beauty from within: Improvement of skin health and appearance with Lycomato a tomato-derived oral supplement

BACKROUND

Healthy and a youthful appearance is a common desire of the aging population. "Beauty from within" involves using nutrition and nutraceuticals to support skin function for reducing and reversing signs of aging such as wrinkles, pigmentary changes, skin laxity, and dullness. Carotenoids possess strong antioxidant and anti-inflammatory activities and are effective in improving skin barrier and could thereby stimulate "beauty from within" by providing endogenous support to reduce the expressions of aging.

AIM

This study was designed to determine whether 3-month supplementation with Lycomato would improve skin condition.

METHOD

A panel of 50 female subjects used Lycomato capsules as nutritional supplements for 3 months. Skin status was observed via questionnaires for the assessment of skin condition and expert visual grading of facial markers such as wrinkles, tonality, roughness, laxity, and pore size. Skin barrier was assessed using transepidermal water loss (TEWL). Measurements were obtained before treatment and after 4 and 12 weeks of use.

RESULTS

Results indicated a statistically significant improvement (p < 0.05) in skin barrier as measured by TEWL after 12 weeks of consuming the supplement. There was also a significant improvement in skin tonality, lines and wrinkles, pore size, and skin firmness as observed by expert evaluation as well as subject self-assessment.

CONCLUSION

Based on the confines and conditions of this study, oral supplementation with Lycomato resulted in significant improvement in skin barrier. Visual appearance of lines and wrinkles, skin tonality, pores, smoothness, and firmness were considerably improved, and these improvements were found to be substantially discernible by the subjects.

Increased Caveolin-2 Expression in Brain Endothelial Cells Promotes Age-Related Neuroinflammation

Aging is a major risk factor for common neurodegenerative diseases. Although multiple molecular, cellular, structural, and functional changes occur in the brain during aging, the involvement of caveolin-2 (Cav-2) in brain ageing remains unknown. We investigated Cav-2 expression in brains of aged mice and its effects on endothelial cells. The human umbilical vein endothelial cells (HUVECs) showed decreased THP-1 adhesion and infiltration when treated with Cav-2 siRNA compared to control siRNA. In contrast, Cav-2 overexpression increased THP-1 adhesion and infiltration in HUVECs. Increased expression of Cav-2 and iba-1 was observed in brains of old mice. Moreover, there were fewer iba-1-positive cells in the brains of aged Cav-2 knockout (KO) mice than of wild-type aged mice. The levels of several chemokines were higher in brains of aged wild-type mice than in young wild-type mice; moreover, chemokine levels were significantly lower in brains of young mice as well as aged Cav-2 KO mice than in their wild-type counterparts. Expression of PECAM1 and VE-cadherin proteins increased in brains of old wild-type mice but was barely detected in brains of young wild-type and Cav-2 KO mice. Collectively, our results suggest that Cav-2 expression increases in the endothelial cells of aged brain, and promotes leukocyte infiltration and age-associated neuroinflammation.

Effect of Lumenato oral supplementation on plasma carotenoid levels and improvement of visual and experiential skin attributes

BACKGROUND

Cellular metabolism and exposure to solar irradiation result in generation of free radicals which are destructive and can lead to premature aging. Antioxidants and free radical scavengers such as carotenoids successfully protect from these free radicals by quenching and neutralizing them thereby strengthening skin barrier which leads to improved skin moisturization, desquamation, and a more youthful look. This study was designed to evaluate the consumer-perceived efficacy of an oral supplement (Lumenato™) containing a mix of tomato carotenoids and oil-soluble vitamins in improving skin appearance after 12 weeks of supplement use.

MATERIALS AND METHODS

Plasma levels of phytoene, phytofluene, zeta-carotene, and lycopene were quantitated before and after 1-, 2-, 3-, and 4-week administration of Lumenato by 24 healthy volunteers. Part II of the study addressed skin visual attributes as assessed by validated tools (questionnaires). A total of 60 females, aged 35 to 55 years, completed part II of the study. The subjects answered questionnaires pertaining to their assessment of skin appearance before and after 12 weeks of taking the supplement.

RESULTS

There was a significant increase (p < 0.001) in plasma levels of phytoene, phytofluene, and zeta-carotene after 1- to 4-week treatment with Lumenato. After 12 weeks of using the supplement, the score of different skin parameters was reported to significantly improve (p < 0.001). Improvement was recorded in skin elasticity, firmness, brightness, skin tone, reduction in dark spots and periorbital dark circles, skin hydration, texture and fine lines and wrinkles. A significant (p < 0.001) improvement in overall skin condition after using the supplement was observed. The subjects noticed statistically significant (p < 0.001) improvement in skin elasticity, firmness, brightness, skin tone, reduction in dark spots and periorbital dark circles, skin hydration, texture and fine lines and wrinkles after 12 weeks of using the supplement. The overall skin condition also exhibited a significant improvement (p < 0.001). Self-assessed improvement of the face was identified at the first time point (4 weeks) and improved significantly (p < 0.001) for the 12 weeks of use. Interestingly, these improvements persisted even after treatment was stopped.

CONCLUSION

Based on the confines and conditions of this study, the use of oral supplement containing a mix of tomato carotenoids significantly increased plasma levels of phytoene, phytofluene, and zeta-carotene, and continuous use resulted in improved facial skin attributes which were palpable by the consumers and continued even after treatment was stopped.

Crosslinking-Induced Corneal Endothelium Dysfunction and Its Protection by Topical Ripasudil Treatment

Purpose

To investigate the changes of corneal endothelium under different crosslinking conditions and the protective effect of ripasudil.

Methods

Corneal crosslinking groups were infiltrated with riboflavin and subsequently irradiated with 0.54 J/cm² or 1.08 J/cm² UVA, while noncrosslinking groups included neither UVA nor riboflavin treatment, only 1.08 J/cm² UVA and only riboflavin treatment. Corneal opacity, variations in corneal endothelial cells, and corneal thickness of all groups were observed by slit lamp, in vivo confocal microscopy, and optical coherence tomography. Immunofluorescence staining and scanning electron microscopy were performed to evaluate changes in the structure and function of the corneal endothelium. The mice that received a corneal crosslinking dose of 1.08 J/cm² were instilled with ripasudil to explore its protective effect on the corneal endothelium.

Results

Treatment with UVA and riboflavin caused an increase in corneal opacity and corneal thickness and decreased endothelial cell density. Furthermore, treatment with UVA and riboflavin caused endothelial cell DNA damage and destroyed the tight junction and pump function of the endothelium, while riboflavin or the same dose of UVA alone did not affect the endothelium. Ripasudil reduced DNA damage in endothelial cells, increased the density of cells, and protected the endothelium's integrity and function.

Conclusion

Riboflavin combined with UVA can damage the corneal endothelium's normal functioning. The corneal endothelium's wound healing is dose-dependent, and the ROCK inhibitor ripasudil maintains the endothelium's pump and barrier functions.

Mechanistic insight into high-fat diet-induced metabolic inflammation in the arcuate nucleus of the hypothalamus

A high-fat diet (HFD) is linked with cytokines production by non-neuronal cells within the hypothalamus, which mediates metabolic inflammation. These cytokines then activate different inflammatory mediators in the arcuate nucleus of the hypothalamus (ARC), a primary hypothalamic area accommodating proopiomelanocortin (POMC) and agouti-related peptide (AGRP) neurons, first-order neurons that sense and integrate peripheral metabolic signals and then respond accordingly. These mediators, such as inhibitor of κB kinase-β (IKKβ), suppression of cytokine signaling 3 (SOCS3), c-Jun N-terminal kinases (JNKs), protein kinase C (PKC), etc., cause insulin and leptin resistance in POMC and AGRP neurons and support obesity and related metabolic complications. On the other hand, inhibition of these mediators has been shown to counteract the impaired metabolism. Therefore, it is important to discuss the contribution of neuronal and non-neuronal cells in HFD-induced hypothalamic inflammation. Furthermore, understanding few other questions, such as the diets causing hypothalamic inflammation, the gender disparity in response to HFD feeding, and how hypothalamic inflammation affects ARC neurons to cause impaired metabolism, will be helpful for the development of therapeutic approaches to prevent or treat HFD-induced obesity.

RIPK1 contributes to cisplatin-induced apoptosis of esophageal squamous cell carcinoma cells via activation of JNK pathway

AIMS

Previous studies have uncovered the function of receptor-interacting protein kinase 1 (RIPK1) to mediate both cell survival and death. Moreover, RIPK1 modulates apoptosis and necroptosis depending on its activity, phosphorylation or ubiquitylation status. Many studies have explained the role or mechanism of RIPK1 in necroptosis. However, the role of RIPK1 has not been elucidated fully in human esophageal squamous cell carcinoma (ESCC) cells.

MATERIALS AND METHODS

The protein and mRNA expression levels of RIPK1 in a panel of ESCC cell lines by Western blot and real-time quantitative reverse transcription PCR (qRT-PCR) were analyzed. MTS assay was used to examine cellular proliferation, flow cytometric analysis to detect apoptosis, mitochondrial membrane potential and reactive oxygen species production. ESCC cells with either inhibitor or overexpressed RIPK1were analyzed to determine cell proliferation, colony formation and apoptosis. Flow cytometry and western blotting assays were used to explore the underlying mechanism.

KEY FINDINGS

In our study, RIPK1 expression was found to contribute significantly to cisplatin-induced apoptosis in the human ESCC cells. The reduced RIPK1 expression promoted cells proliferation and overexpressed RIPK1 facilitated cell apoptosis. Mechanistic investigations have revealed that the inhibition of proliferation for RIPK1 in ESCC cells was regulated via activation of c-Jun NH2-terminal kinase signaling. Additionally, damages were observed in the mitochondrial membrane, depletion of ATP and increased generation in reactive oxygen species.

SIGNIFICANCE

Our findings verified the evidence that RIPK1 can promote cell death in ESCC cells, with potential implications for activating c-Jun NH2-terminal kinase pathway as a novel approach to the disease.

Novel proteomic changes in brain mitochondria provide insights into mitochondrial dysfunction in mouse models of Huntington's disease

Huntington's disease (HD) is a progressive ultimately fatal disorder caused by a glutamine-encoding CAG expansion in the huntingtin (HTT) gene that results in degeneration mainly in striatal and cerebro-cortical brain regions. Mitochondrial dysfunction is one important facet of HD pathogenesis. Here we used R6/2 and YAC128 HD mouse models of human HD, that express different HTT transgenes and have different progression rates, to identify HD brain mitochondrial proteomic signatures. Cerebral cortical mitochondrial preparations from HD and wild-type litter mate mice were compared by two-dimensional SDS-PAGE electrophoresis and MALDI-TOF/TOF mass spectrometry. Proteomic analyses inferred 17 and 12 differentially expressed proteins, respectively in 12 week R6/2 and 15 month YAC128 HD mice, compared to controls. Peroxiredoxin 3, stress-70, DJ-1, isocitrate dehydrogenase [NAD] α subunit and ATP synthase subunit D were differentially expressed in both models. Using the PANTHER (Protein ANalysis THrough Evolutionary Relationships) classification system we show that the inferred proteins are involved in oxidative stress defense, oxidative phosphorylation, the citric acid cycle, pyruvate metabolism, apoptosis, protein folding and iron metabolism. Common mitochondrial proteomic changes are significant in mouse models of middle (YAC128) and advanced (R6/2) HD despite differences in the HTT transgenes, age, genetic background and disease stage. The findings identify a proteomic signature of HD mitochondria in mouse models that includes previously unrecognized proteins.

Weight of evidence evaluation of a network of adverse outcome pathways linking activation of the nicotinic acetylcholine receptor in honey bees to colony death

Ongoing honey bee (Apis mellifera) colony losses are of significant international concern because of the essential role these insects play in pollinating crops. Both chemical and non-chemical stressors have been implicated as possible contributors to colony failure; however, the potential role(s) of commonly-used neonicotinoid insecticides has emerged as particularly concerning. Neonicotinoids act on the nicotinic acetylcholine receptors (nAChRs) in the central nervous system to eliminate pest insects. However, mounting evidence indicates that neonicotinoids also may adversely affect beneficial pollinators, such as the honey bee, via impairments on learning and memory, and ultimately foraging success. The specific mechanisms linking activation of the nAChR to adverse effects on learning and memory are uncertain. Additionally, clear connections between observed impacts on individual bees and colony level effects are lacking. The objective of this review was to develop adverse outcome pathways (AOPs) as a means to evaluate the biological plausibility and empirical evidence supporting (or refuting) the linkage between activation of the physiological target site, the nAChR, and colony level consequences. Potential for exposure was not a consideration in AOP development and therefore this effort should not be considered a risk assessment. Nonetheless, development of the AOPs described herein has led to the identification of research gaps which, for example, may be of high priority in understanding how perturbation of pathways involved in neurotransmission can adversely affect normal colony functions, causing colony instability and subsequent bee population failure. A putative AOP network was developed, laying the foundation for further insights as to the role of combined chemical and non-chemical stressors in impacting bee populations. Insights gained from the AOP network assembly, which more realistically represents multi-stressor impacts on honey bee colonies, are promising toward understanding common sensitive nodes in key biological pathways and identifying where mitigation strategies may be focused to reduce colony losses.

Age-related alterations in the sarcolemmal environment are attenuated by lifelong caloric restriction and voluntary exercise

Age-related loss of skeletal muscle mass and function, referred to as sarcopenia, is mitigated by lifelong calorie restriction as well as exercise. In aged skeletal muscle fibers there is compromised integrity of the cell membrane that may contribute to sarcopenia. The purpose of this study was to determine if lifelong mild (8%) caloric restriction (CR) and lifelong CR+voluntary wheel running (WR) could ameliorate disruption of membrane scaffolding and signaling proteins during the aging process, thus maintaining a favorable, healthy membrane environment in plantaris muscle fibers. Fischer-344 rats were divided into four groups: 24-month old adults fed ad libitum (OAL); 24-month old on 8% caloric restriction (OCR); 24month old 8% caloric restriction+wheel running (OCRWR); and 6-month old sedentary adults fed ad libitum (YAL) were used to determine age-related changes. Aging resulted in discontinuous membrane expression of dystrophin glycoprotein complex (DGC) proteins: dystrophin and α-syntrophin. Older muscle also displayed decreased content of neuronal nitric oxide synthase (nNOS), a key DGC signaling protein. In contrast, OCR and OCRWR provided significant protection against age-related DGC disruption. In conjunction with the age-related decline in membrane DGC patency, key membrane repair proteins (MG53, dysferlin, annexin A6, and annexin A2) were significantly increased in the OAL plantaris. However, lifelong CR and CRWR interventions were effective at maintaining membrane repair proteins near YAL levels of. OAL fibers also displayed reduced protein content of NADPH oxidase isoform 2 (Nox2) subunits (p67phox and p47phox), consistent with a perturbed sarcolemmal environment. Loss of Nox2 subunits was prevented by lifelong CR and CRWR. Our results are therefore consistent with the hypothesis that lifelong CR and WR are effective countermeasures against age-related alterations in the myofiber membrane environment.

Geissoschizine methyl ether protects oxidative stress-mediated cytotoxicity in neurons through the 'Neuronal Warburg Effect'

ETHNOPHARMACOLOGICAL RELEVANCE

The rate of production of reactive oxygen species (ROS) is determined by mitochondrial metabolic rate. In turn, excessive ROS damage mitochondrial function, which is linked to aging and neurodegenerative conditions. One possible path to prevent oxidative stress could be achieved by reducing mitochondrial respiration in favor of less efficient ATP production via glycolysis. Such a shift in energy metabolism is known as the 'Warburg effect'. Geissoschizine methyl ether (GM) is one of the active components responsible for the psychotropic effects of Yokukansan, an herbal preparation widely used in China and Japan.

AIM OF THE STUDY

GM protects neurons from glutamate-induced oxidative cytotoxicity through regulating mitochondrial function and suppressing ROS generation. We investigated the protective mechanism of GM against glutamate-induced oxidative stress in neuronal cells.

MATERIALS AND METHODS

The current study was performed on primary neurons and HT22 cells, a hippocampus neuronal cell line. Cell viability was measured by Calcein AM assay. H2DCFDA staining was used for intracellular ROS measurement. GSH level was measured using the GSH-Glo™ luminescence-based assay. Mitochondrial respiration and glycolysis were measured by the Seahorse Bioscience XFe 96 Extracellular Flux Analyzer. Protein levels were analyzed by western blot analysis.

RESULTS

GM prevented glutamate-induced cytotoxicity in an HT-22 neuronal cell line even with a 9-hour exposure delay. GM blocked glutamate-induced intracellular ROS accumulation through suppressing mitochondrial respiration. Further, we found that GM up-regulated glycolysis and the pentose-phosphate pathway, which is involved in the production of intracellular reducing agent, NADPH. In addition, GM protected primary cortical neurons from both glutamate and buthioninesulfoximine toxicity.

CONCLUSION

GM prevents glutamate-induced oxidative damage through reducing mitochondrial respiration, which further suppresses ROS generation. In addition, GM up-regulates glycolysis which compensate for the energy depletion induced by mitochondrial respiration inhibition. Overall, our study is the first to report that GM protects neurons from oxidative toxicity by shifting energy metabolism from mitochondrial respiration to glycolysis.

Protein undernutrition during development and oxidative impairment in the central nervous system (CNS): potential factors in the occurrence of metabolic syndrome and CNS disease

Mitochondria play a regulatory role in several essential cell processes including cell metabolism, calcium balance and cell viability. In recent years, it has been postulated that mitochondria participate in the pathogenesis of a number of chronic diseases, including central nervous system disorders. Thus, the concept of mitochondrial function now extends far beyond the common view of this organelle as the ‘powerhouse’ of the cell to a new appreciation of the mitochondrion as a transducer of early metabolic insult into chronic disease in later life. In this review, we have attempted to describe some of the associations between nutritional status and mitochondrial function (and dysfunction) during embryonic development with the occurrence of neural oxidative imbalance and neurogenic disease in adulthood.

Tert-butylhydroquinone compromises survival in murine experimental stroke

Tert-butylhydroquinone (tBHQ), an Nrf2 signaling pathway inducer that is widely used as a food additive in the U.S., prevents oxidative stress-induced cytotoxicity in neurons. This study assesses the effects of tBHQ on ischemic stroke outcomes in mice. We measured infarct size, neurological deficits, and brain volume after tBHQ treatments in murine permanent middle cerebral artery occlusion (pMCAO) model in vivo. Further, we evaluated the regulation of tBHQ on mitochondrial function in cerebrovascular endothelial cells in vitro, which is critical to the blood-brain barrier (BBB) permeability. Our results demonstrated that tBHQ increased post-stroke mortality and worsened stroke outcomes. Mitochondrial function was suppressed by tBHQ treatment of cerebrovascular endothelial cells, and this suppression was potentiated by co-treatment with lipopolysaccharide (LPS), the bacterial mimic. These data indicate that tBHQ-exacerbated stroke damage might due to the compromised BBB permeability in permanent stroke.

Redox regulation of muscle adaptations to contractile activity and aging

Superoxide and nitric oxide are generated by skeletal muscle, and these species are increased by contractile activity. Mitochondria have long been assumed to play the primary role in generation of superoxide in muscle, but recent studies indicate that, during contractile activity, membrane-localized NADPH oxidase(s) rapidly generate(s) superoxide that plays a role in redox signaling. This process is important in upregulation of rapid and specific cytoprotective responses that aid maintenance of cell viability following contractile activity, but the overall extent to which redox signaling contributes to regulation of muscle metabolism and homeostasis following contractile activity is currently unclear, as is identification of key redox-sensitive protein targets involved in these processes. Reactive oxygen and nitrogen species have also been implicated in the loss of muscle mass and function that occurs with aging, although recent work has questioned whether oxidative damage plays a key role in these processes. A failure of redox signaling occurs in muscle during aging and may contribute to the age-related loss of muscle fibers. Whether such changes in redox signaling reflect primary age-related changes or are secondary to the fundamental mechanisms is unclear. For instance, denervated muscle fibers within muscles from aged rodents or humans appear to generate large amounts of mitochondrial hydrogen peroxide that could influence adjacent innervated fibers. Thus, in this instance, a "secondary" source of reactive oxygen species may be potentially generated as a result of a primary age-related pathology (loss of neurons), but, nevertheless, may contribute to loss of muscle mass and function during aging.

Heat stress induced apoptosis is triggered by transcription-independent p53, Ca(2+) dyshomeostasis and the subsequent Bax mitochondrial translocation

In this study, We demonstrated that Bax mitochondrial translocation plays a vital role in the initiation of the mitochondrial signaling pathway upon activation by heat stress. In addition, both p53 mitochondrial translocation and Ca²⁺ signal mediated MPTP opening activate Bax mitochondrial translocation. Employing pifithrin-α (a p53 mitochondrial translocation inhibitor) and CsA (a permeability transition pore (MPTP) inhibitor), we found that heat stress induced Bax mitochondrial translocation was significantly inhibited in cells pretreated with both PFT and CsA. Furthermore, we demonstrated that generation of reactive oxygen species (ROS) is a critical mediator in heat stress induced apoptosis and that the antioxidant MnTBAP significantly decreased heat stress induced p53 mitochondrial translocation and Ca²⁺ signal mediated MPTP opening, as well as the subsequent Bax mitochondrial translocation and activation of the caspase cascade. Taken together, our results indicate that heat stress induces apoptosis through the mitochondrial pathway with ROS dependent mitochondrial p53 translocation and Ca²⁺ dyshomeostasis, and the ensuing intro Bax mitochondrial translocation as the upstream events involved in triggering the apoptotic process observed upon cellular exposure to heat stress.

The mitochondrial Na(+)/Ca(2+) exchanger may reduce high glucose-induced oxidative stress and nucleotide-binding oligomerization domain receptor 3 inflammasome activation in endothelial cells

Background

The mitochondrial Na⁺/Ca²⁺ exchanger, NCLX, plays an important role in the balance between Ca²⁺ influx and efflux across the mitochondrial inner membrane in endothelial cells. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca²⁺ activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy production but are also important sites of reactive oxygen species (ROS) generation and nucleotide-binding oligomerization domain receptor 3 (NLRP3) inflammasome activation.

Methods & Results

This study focused on NCLX function, in rat aortic endothelial cells (RAECs), induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct (siNCLX), enhanced mitochondrial Ca²⁺ influx and blocked efflux induced by glucose. Unexpectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation.

Conclusions

These findings suggest that NCLX affects glucose-dependent mitochondrial Ca²⁺ signaling, thereby regulating ROS generation and NLRP3 inflammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.

Molecular transitions from papillomavirus infection to cervical precancer and cancer: Role of stromal estrogen receptor signaling

To study the multistep process of cervical cancer development, we analyzed 128 frozen cervical samples spanning normalcy, increasingly severe cervical intraepithelial neoplasia (CIN1- CIN3), and cervical cancer (CxCa) from multiple perspectives, revealing a cascade of progressive changes. Compared with normal tissue, expression of many DNA replication/repair and cell proliferation genes was increased in CIN1/CIN2 lesions and further sustained in CIN3, consistent with high-risk human papillomavirus (HPV)-induced tumor suppressor inactivation. The CIN3-to-CxCa transition showed metabolic shifts, including decreased expression of mitochondrial electron transport complex components and ribosomal protein genes. Significantly, despite clinical, epidemiological, and animal model results linking estrogen and estrogen receptor alpha (ERα) to CxCa, ERα expression declined >15-fold from normalcy to cancer, showing the strongest inverse correlation of any gene with the increasing expression of p16, a marker for HPV-linked cancers. This drop in ERα in CIN and tumor cells was confirmed at the protein level. However, ERα expression in stromal cells continued throughout CxCa development. Our further studies localized stromal ERα to FSP1+, CD34+, SMA- precursor fibrocytes adjacent to normal and precancerous CIN epithelium, and FSP1-, CD34-, SMA+ activated fibroblasts in CxCas. Moreover, rank correlations with ERα mRNA identified IL-8, CXCL12, CXCL14, their receptors, and other angiogenesis and immune cell infiltration and inflammatory factors as candidates for ERα-induced stroma-tumor signaling pathways. The results indicate that estrogen signaling in cervical cancer has dramatic differences from ERα+ breast cancers, and imply that estrogen signaling increasingly proceeds indirectly through ERα in tumor-associated stromal fibroblasts.

Nicotinamide exerts antioxidative effects on senescent cells

Nicotinamide (NAM) has been shown to suppress reactive oxygen species (ROS) production in primary human fibroblasts, thereby extending their replicative lifespan when added to the medium during long-term cultivation. Based on this finding, NAM is hypothesized to affect cellular senescence progression by keeping ROS accumulation low. In the current study, we asked whether NAM is indeed able to reduce ROS levels and senescence phenotypes in cells undergoing senescence progression and those already in senescence. We employed two different cellular models: MCF-7 cells undergoing senescence progression and human fibroblasts in a state of replicative senescence. In both models, NAM treatment substantially decreased ROS levels. In addition, NAM attenuated the expression of the assessed senescence phenotypes, excluding irreversible growth arrest. N-acetyl cysteine, a potent ROS scavenger, did not have comparable effects in the tested cell types. These data show that NAM has potent antioxidative as well as anti-senescent effects. Moreover, these findings suggest that NAM can reduce cellular deterioration caused by oxidative damage in postmitotic cells in vivo.

Mitochondrial energy metabolism and redox signaling in brain aging and neurodegeneration

SIGNIFICANCE

The mitochondrial energy-transducing capacity is essential for the maintenance of neuronal function, and the impairment of energy metabolism and redox homeostasis is a hallmark of brain aging, which is particularly accentuated in the early stages of neurodegenerative diseases.

RECENT ADVANCES

The communications between mitochondria and the rest of the cell by energy- and redox-sensitive signaling establish a master regulatory device that controls cellular energy levels and the redox environment. Impairment of this regulatory devise is critical for aging and the early stages of neurodegenerative diseases.

CRITICAL ISSUES

This review focuses on a coordinated metabolic network-cytosolic signaling, transcriptional regulation, and mitochondrial function-that controls the cellular energy levels and redox status as well as factors which impair this metabolic network during brain aging and neurodegeneration.

FUTURE DIRECTIONS

Characterization of mitochondrial function and mitochondria-cytosol communications will provide pivotal opportunities for identifying targets and developing new strategies aimed at restoring the mitochondrial energy-redox axis that is compromised in brain aging and neurodegeneration.

Interactions between reactive oxygen species generated by contractile activity and aging in skeletal muscle?

SIGNIFICANCE

Aging leads to a loss of skeletal muscle mass and function that causes instability, increased risk of falls, and need for residential care. This is due to a reduction in the muscle mass and strength that is primarily due caused by a decrease in the number of muscle fibers, particularly, type II fibers, and atrophy and weakening of those remaining.

RECENT ADVANCES

Although increased oxidative damage was originally thought to be the key to the aging process, data now indicate that reactive oxygen species (ROS) may be one of the several components of the degenerative processes in aging. The skeletal muscle shows important rapid adaptations to the ROS generated by contractions that are attenuated in aged organisms and transgenic studies have indicated that overcoming these attenuated responses can prevent the age-related loss of muscle mass and function.

CRITICAL ISSUES

Elucidation of the mechanisms by which the skeletal muscle adapts to the ROS generated to contractions and the way in which these processes are attenuated by aging is critical to the development of logical approaches to prevent age-related loss of muscle mass and function.

FUTURE DIRECTIONS

Future studies are likely to focus on the redox regulation of adaptive pathways and their maintenance during aging as an approach to maintain and improve muscle function.

Redox homeostasis in pancreatic β cells

We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.

Inflammatory cause of metabolic syndrome via brain stress and NF-κB

Metabolic syndrome, a network of medical disorders that greatly increase the risk for developing metabolic and cardiovascular diseases, has reached epidemic levels in many areas of today's world. Despite this alarming medicare situation, scientific understandings on the root mechanisms of metabolic syndrome are still limited, and such insufficient knowledge contributes to the relative lack of effective treatments or preventions for related diseases. Recent interdisciplinary studies from neuroendocrinology and neuroimmunology fields have revealed that overnutrition can trigger intracellular stresses to cause inflammatory changes mediated by molecules that control innate immunity. This type of nutrition-related molecular inflammation in the central nervous system, particularly in the hypothalamus, can form a common pathogenic basis for the induction of various metabolic syndrome components such as obesity, insulin resistance, and hypertension. Proinflammatory NF-κB pathway has been revealed as a key molecular system for pathologic induction of brain inflammation, which translates overnutrition and resulting intracellular stresses into central neuroendocrine and neural dysregulations of energy, glucose, and cardiovascular homeostasis, collectively leading to metabolic syndrome. This article reviews recent research advances in the neural mechanisms of metabolic syndrome and related diseases from the perspective of pathogenic induction by intracellular stresses and NF-κB pathway of the brain.

Unincorporated iron pool is linked to oxidative stress and iron levels in Caenorhabditis elegans

Free radicals or reactive oxygen species (ROS) are relatively short-lived and are difficult to measure directly; so indirect methods have been explored for measuring these transient species. One technique that has been developed using Escherichia coli and Saccharomyces cerevisiae systems, relies on a connection between elevated superoxide levels and the build-up of a high-spin form of iron (Fe(III)) that is detectable by electron paramagnetic resonance (EPR) spectroscopy at g = 4.3. This form of iron is referred to as "free" iron. EPR signals at g = 4.3 are commonly encountered in biological samples owing to mononuclear high-spin (S = 5/2) Fe(III) ions in sites of low symmetry. Unincorporated iron in this study refers to this high-spin Fe(III) that is captured by desferrioxamine which is detected by EPR at g value of 4.3. Previously, we published an adaptation of Fe(III) EPR methodology that was developed for Caenorhabditis elegans, a multi-cellular organism. In the current study, we have systematically characterized various factors that modulate this unincorporated iron pool. Our results demonstrate that the unincorporated iron as monitored by Fe(III) EPR at g = 4.3 increased under conditions that were known to elevate steady-state ROS levels in vivo, including: paraquat treatment, hydrogen peroxide exposure, heat shock treatment, or exposure to higher growth temperature. Besides the exogenous inducers of oxidative stress, physiological aging, which is associated with elevated ROS and ROS-mediated macromolecular damage, also caused a build-up of this iron. In addition, increased iron availability increased the unincorporated iron pool as well as generalized oxidative stress. Overall, unincorporated iron increased under conditions of oxidative stress with no change in total iron levels. However, when total iron levels increased in vivo, an increase in both the pool of unincorporated iron and oxidative stress was observed suggesting that the status of the unincorporated iron pool is linked to oxidative stress and iron levels.

Redox regulation of mitochondrial function

Redox-dependent processes influence most cellular functions, such as differentiation, proliferation, and apoptosis. Mitochondria are at the center of these processes, as mitochondria both generate reactive oxygen species (ROS) that drive redox-sensitive events and respond to ROS-mediated changes in the cellular redox state. In this review, we examine the regulation of cellular ROS, their modes of production and removal, and the redox-sensitive targets that are modified by their flux. In particular, we focus on the actions of redox-sensitive targets that alter mitochondrial function and the role of these redox modifications on metabolism, mitochondrial biogenesis, receptor-mediated signaling, and apoptotic pathways. We also consider the role of mitochondria in modulating these pathways, and discuss how redox-dependent events may contribute to pathobiology by altering mitochondrial function.

Hypothalamic inflammation: a double-edged sword to nutritional diseases

The hypothalamus is one of the master regulators of various physiological processes, including energy balance and nutrient metabolism. These regulatory functions are mediated by discrete hypothalamic regions that integrate metabolic sensing with neuroendocrine and neural controls of systemic physiology. Neurons and nonneuronal cells in these hypothalamic regions act supportively to execute metabolic regulations. Under conditions of brain and hypothalamic inflammation, which may result from overnutrition-induced intracellular stresses or disease-associated systemic inflammatory factors, extracellular and intracellular environments of hypothalamic cells are disrupted, leading to central metabolic dysregulations and various diseases. Recent research has begun to elucidate the effects of hypothalamic inflammation in causing diverse components of metabolic syndrome leading to diabetes and cardiovascular disease. These new understandings have provocatively expanded previous knowledge on the cachectic roles of brain inflammatory response in diseases, such as infections and cancers. This review describes the molecular and cellular characteristics of hypothalamic inflammation in metabolic syndrome and related diseases as opposed to cachectic diseases, and also discusses concepts and potential applications of inhibiting central/hypothalamic inflammation to treat nutritional diseases.

High glucose-induced Ca2+ overload and oxidative stress contribute to apoptosis of cardiac cells through mitochondrial dependent and independent pathways

BACKGROUND

Cardiac cell apoptosis is the initiating factor of cardiac complications especially diabetic cardiomyopathy. Mitochondria are susceptible to the damaging effects of elevated glucose condition. Calcium overload and oxidative insult are the two mutually non-exclusive phenomena suggested to cause cardiac dysfunction. Here, we examined the effect of high-glucose induced calcium overload in calpain-1 mediated cardiac apoptosis in an in vitro setting.

METHODS

H9c2, rat ventricular myoblast cell line was treated with elevated glucose condition and the cellular consequences were studied. Intracellular calcium trafficking, ROS generation, calpain-1 activation and caspase-12 and caspase-9 pathway were studied using flow cytometry, confocal microscopy and Western blot analysis.

RESULTS

High-glucose treatment resulted in increased intracellular calcium ([Ca2+]i) which was mobilized to the mitochondria. Concomitant intra-mitochondrial calcium ([Ca2+]m) increase resulted in enhanced reactive oxygen and nitrogen species generation. These events led to mitochondrial dysfunction and apoptosis. Cardiomyocyte death exhibited several classical markers of apoptosis, including activation of caspases, appearance of annexin V on the outer plasma membrane, increased population of cells with sub-G0/G1 DNA content and nuclear condensation. Key findings include elucidation of cell signaling mechanism of high-glucose induced calcium-dependent cysteine protease calpain-1 activation, which triggers non-conventional caspases as alternate mode of cell death.

CONCLUSION

This information increases the understanding of cardiac cell death under hyperglycemic condition and can possibly be extended for designing new therapeutic strategies for diabetic cardiomyopathy.

GENERAL SIGNIFICANCE

The novel findings of the study reveal that high glucose induces apoptosis by both mitochondria-dependent and independent pathways via concomitant rise in intracellular calcium.

Insulin-like growth factor-1 receptor activation prevents hydrogen peroxide-induced oxidative stress, mitochondrial dysfunction and apoptosis

Vascular disease is the leading cause of morbidity and mortality. Oxidative stress can cause endothelial cell apoptosis. Low insulin like growth factor-1 (IGF-1) has been linked to adverse risk profile and increased vascular disease incidence. Since IGF-1 acts as an important survival factor for multiple cell types, we undertook this study to investigate whether IGF-1 favorably affects oxidative-stress mediated apoptosis of vascular endothelial cells. Exposure to hydrogen peroxide induced apoptotic changes (e.g. DNA fragmentation, altered mitochondrial membrane potential and caspase-3 activity) in human umbilical vein endothelial cells (HUVECs) in a time dependent manner. Addition of IGF-1 blocked the oxidative-stress effect parallel to IGF-1 receptor (IGF-1R) expression, and silencing the IGF-1R with small interference RNA attenuated the IGF-1 influence. Our findings show that enhanced IGF-1 signaling inhibits oxidative-stress induced apoptosis in HUVECs by reducing mitochondrial dysfunction. Specifically the protective mechanism of IGF-1 involves preserving the mitochondrial membrane potential, maintaining the mitochondrial retention of cytochrome-c, and reducing caspase-3 activity. These results may have therapeutic implications in preventing/reducing vascular disease associated endothelial dysfunction.

Proliferative capacity of corneal endothelial cells

The corneal endothelial monolayer helps maintain corneal transparency through its barrier and ionic "pump" functions. This transparency function can become compromised, resulting in a critical loss in endothelial cell density (ECD), corneal edema, bullous keratopathy, and loss of visual acuity. Although penetrating keratoplasty and various forms of endothelial keratoplasty are capable of restoring corneal clarity, they can also have complications requiring re-grafting or other treatments. With the increasing worldwide shortage of donor corneas to be used for keratoplasty, there is a greater need to find new therapies to restore corneal clarity that is lost due to endothelial dysfunction. As a result, researchers have been exploring alternative approaches that could result in the in vivo induction of transient corneal endothelial cell division or the in vitro expansion of healthy endothelial cells for corneal bioengineering as treatments to increase ECD and restore visual acuity. This review presents current information regarding the ability of human corneal endothelial cells (HCEC) to divide as a basis for the development of new therapies. Information will be presented on the positive and negative regulation of the cell cycle as background for the studies to be discussed. Results of studies exploring the proliferative capacity of HCEC will be presented and specific conditions that affect the ability of HCEC to divide will be discussed. Methods that have been tested to induce transient proliferation of HCEC will also be presented. This review will discuss the effect of donor age and endothelial topography on relative proliferative capacity of HCEC, as well as explore the role of nuclear oxidative DNA damage in decreasing the relative proliferative capacity of HCEC. Finally, potential new research directions will be discussed that could take advantage of and/or improve the proliferative capacity of these physiologically important cells in order to develop new treatments to restore corneal clarity.

Respiration and ROS production in brain and spinal cord mitochondria of transgenic rats with mutant G93a Cu/Zn-superoxide dismutase gene

Mitochondrial dysfunction is involved in the pathogenesis of motor neuron degeneration in the G93A mutant transgenic (tgmSOD1) animal model of ALS. However, it is unknown whether mitochondriopathy is a primary or secondary event. We isolated brain (BM) and spinal cord (SCM) mitochondria from 2 month old presymptomatic tgmSOD1 rats and studied respiration and generation of reactive oxygen species (ROS) using a new metabolic paradigm (Panov et al., Am. J. Physiol., Regul. Integr. Comp. Physiol., 2011). The yields of BM and SCM from tgmSOD1 rats were 27% and 58% lower than normal rats (WT). The rates of the State 3 and State 3U respiration of tgBM and tgSCM were normal with glutamate+pyruvate+malate as substrates but were inhibited with pyruvate+malate in tgBM and glutamate+malate in tgSCM. In tgSCM the State 4 respiration with all substrates was significantly (1.5-2 fold) increased as compared with WT-SCM. Western blot analysis showed that tgSCM had lower contents of complexes III (-60%) and IV (-35%), and the presence of mutated SOD1 protein in both tgBM and tgSCM. With glutamate+pyruvate+malate or succinate+glutamate+pyruvate+malate as substrates, tgBM and tgSCM generated 5-7 fold more ROS than normal mitochondria, and tgSCM generated two times more ROS than tgBM. We show that the major damaging ROS species in tgmSOD1 animals is H(2)O(2). It is known that mutated SOD1, damaged by H(2)O(2), associates with mitochondria, and we suggest that this further increases production of H(2)O(2). We also show that the total tissue calcium content remained normal in the brain but was diminished by 26% in the spinal cord of presymptomatic tgmSOD1 rats.

CONCLUSION

In tgSCM abnormally high rates of ROS generation, associated with reverse electron transport, result in accelerated mitochondriopathy, and the Ca(2+)-dependent excitotoxic death of motor neurons. Thus mitochondrial dysfunction is a key early element in pathogenesis of motor neuron degeneration in tgmSOD1 rats.

Carotenoids in human skin

The interaction of free radicals with antioxidants is a topic of increasing interest in the development of prevention strategies against skin ageing. Carotenoids can serve as marker substances for the complete antioxidative network of human skin. Recently, it has become possible to measure the carotenoids non-invasively and online using resonance Raman spectroscopy. This method has been used in various studies to investigate the interaction of carotenoid antioxidants and free radicals in human skin. In this review, the results of the selected studies are summarized and compared. It could be demonstrated that the carotenoid concentration of the skin reflects the lifestyle of individuals. A high level of carotenoids can be achieved with a healthy diet rich, for instance, in fruit and vegetables. Stress factors such as illness, UV and IR radiation of the sun, and smoking and alcohol consumption reduce the concentration of the carotenoids in the skin. It could be demonstrated that premature skin ageing was less in people with a high level of antioxidants in their tissue. Consequently, the furrows and wrinkles were not so deep and dense as in the skin of individuals with a low antioxidant level. The measurements are highly suited for the development of anti-ageing strategies and can be efficiently used in the medical diagnostics and therapy control.

Age-related gene response of human corneal endothelium to oxidative stress and DNA damage

PURPOSE

Nuclear oxidative DNA damage increases with age in human corneal endothelial cells (HCECs) and contributes to their decreased proliferative capacity. These studies investigated whether HCECs respond to this damage by upregulating their expression of oxidative stress and DNA damage-signaling genes in an age-dependent manner.

METHODS

HCECs were dissected from the corneas of young (30 years and younger) and older (50 years and older) donors. Total RNA was isolated and reverse-transcribed. Oxidative stress and DNA damage-signaling gene expression were analyzed using commercial PCR-based microarrays. Western blot analyses were conducted on selected proteins to verify the microarray results. Nuclear DNA damage foci were detected in the endothelium of ex vivo corneas by immunostaining for H2AX-Ser139.

RESULTS

Four of 84 genes showed a statistically significant age-related difference in the expression of oxidative stress-related genes; however, Western blot analysis demonstrated an age-related increase in only 2 (cytoglobin and GPX-1) of 11 proteins tested. No age-related differences were detected in the expression of DNA damage-signaling genes. Western blot analysis of seven DNA damage-related proteins verified this finding. Intense nuclear staining of DNA damage foci was observed in nuclei within the central endothelium of older donors. Central endothelium from young donors consistently showed a low level of positive staining.

CONCLUSIONS

HCECs respond to age-related increases in oxidative nuclear DNA damage by forming DNA damage repair foci; however, they do not vigorously defend against or repair this damage by upregulating the expression of multiple oxidative stress or DNA damage-signaling genes.

Metabolic and functional differences between brain and spinal cord mitochondria underlie different predisposition to pathology

Mitochondrial dysfunctions contribute to neurodegeneration, the locations of which vary among neurodegenerative diseases. To begin to understand what mechanisms may underlie higher vulnerability of the spinal cord motor neurons in amyotrophic lateral sclerosis, compared with brain mitochondria, we studied three major functions of rat brain mitochondria (BM) and spinal cord mitochondria (SCM) mitochondria: oxidative phosphorylation, Ca(2+) sequestration, and production of reactive oxygen species (ROS), using a new metabolic paradigm (Panov et al., J. Biol. Chem. 284: 14448-14456, 2009). We present data that SCM share some unique metabolic properties of the BM. However, SCM also have several distinctions from the BM: 1) With the exception of succinate, SCM show significantly lower rates of respiration with all substrates studied; 2) immunoblotting analysis showed that this may be due to 30-40% lower contents of respiratory enzymes and porin; 3) compared with BM, SCM sequestered 40-50% less Ca(2+), and the total tissue calcium content was 8 times higher in the spinal cord; 4) normalization for mitochondria from 1 g of tissue showed that BM can sequester several times more Ca(2+) than was available in the brain tissue, whereas SCM had the capacity to sequester only 10-20% of the total tissue Ca(2+); and 5) with succinate and succinate-containing substrate mixtures, SCM showed significantly higher state 4 respiration than BM and generated more ROS associated with the reverse electron transport. We conclude that SCM have an intrinsically higher risk of oxidative damage and overload with calcium than BM, and thus spinal cord may be more vulnerable under some pathologic conditions. (250).

C-jun inhibits mammary apoptosis in vivo

c-jun, which is overexpressed in a number of human cancers encodes a critical component of the AP-1 complex. c-jun has been shown to either induce or inhibit cellular apoptosis. Germ line deletion of both c-jun alleles is embryonically lethal. To determine the role of the endogenous c-jun gene in apoptosis, we performed mammary epithelial cell-targeted somatic deletion using floxed c-jun (c-jun(f/f)) conditional knockout mice. Laser capture microdissection demonstrated endogenous c-jun inhibits expression of apoptosis inducing genes and reactive oxygen species (ROS)-reducing genes (MnSOD, catalase). ROS have been implicated in apoptosis and undergo enzymatic elimination via MnSOD and CuZnSOD with further detoxification via catalase. c-jun-mediated survival was in part dependent on ROS production. c-jun-mediated repression of MnSOD and catalase occurred via mitochondrial complex I and NOX I. Collectively, these studies define a pivotal role of endogenous c-jun in promoting cell survival via maintaining mitochondrial integrity and expression of the key regulators of ROS production.

Differentially abundant transcripts in PBMC of hospitalized geriatric patients with hip fracture compared to healthy aged controls

The abundance of a selection of transcript species involved in inflammation, immunosenescence and stress response was compared between PBMC of 35 geriatric patients with hip fracture in acute phase (days 2-4 after hospitalization) or convalescence phase (days 7-10) and 28 healthy aged controls. Twenty-nine differentially abundant transcripts were identified in acute phase versus healthy ageing. Twelve of these transcripts remained differentially abundant in convalescence phase, and 22 were similarly differentially abundant in acute phase of geriatric infectious diseases. Seven of these 22 transcripts were previously identified as differentially abundant in PBMC of healthy aged versus healthy young controls, with further alteration for CD28, CD69, LCK, CTSD, HMOX1, and TNFRSF1A in acute phase after geriatric hip fracture and infectious diseases. The next question is whether these alterations are common to other geriatric diseases and/or preexist before the clinical onset of the diseases.

Pharmacologic concentrations of melatonin have diverse influence on differential expressions of angiogenic chemokine genes in different hepatocellular carcinoma cell lines

This study was to investigate whether melatonin (MLT) at pharmacologic concentrations (1 and 100 μM) had potential to influence the expressions of angiogenic (CCL2, CXCL6, IL8) and angiostatic (CXCL10) chemokine genes in two hepatocellular carcinoma (HCC) cell lines with different characteristics (cell line A, HCC24/KMUH, without susceptible to amphotericin B (AmB)-induced oxidative stress; cell line B, HCC38/KMUH, susceptible to AmB-induced oxidative stress). Differential expression of gene was investigated by quantitative reverse transcriptase-polymerase chain reaction. Two genes related to oxidative stress (SOD2, VNN3) were also studied. One and 100 μM MLT up-regulated CCL2, IL8 and CXCL10 genes in cell line A but down-regulated CCL2, CXCL6, IL8 and SOD2 genes in cell line B. CXCL10 gene was up-regulated by 1 and 100 μM MLT in both cell lines. SOD2 gene was down-regulated by 1 and 100 μM MLT only in cell line B. The magnitudes of gene expression fold changes of CCL2 and IL8 genes in cell line A and CCL2, CXCL6, IL8 and SOD2 genes in cell line B were similar between 1 and 100 μM MLT. The magnitudes of gene expression fold change of up-regulated CXCL10 gene in both cell lines were smaller in 100 μM MLT than in 1 μM MLT. In conclusion, the responses of angiogenic chemokine genes to MLT were mainly determined by the characteristics of cancer cells. The concentration of MLT may be the main determinant for the response of angiostatic CXCL10 gene to MLT. Clinical application of MLT in patients with HCC should consider these effects.

WITHDRAWN: Oxidative stress in aging: Theoretical outcomes and clinical evidences in humans

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.biomag.2011.03.001. The duplicate article has therefore been withdrawn.

Transcriptomic biomarkers of the response of hospitalized geriatric patients with infectious diseases

Background

Infectious diseases are significant causes of morbidity and mortality among elderly populations. However, the relationship between oxidative stress, immune function and inflammatory response in acute phase of the infectious disease is poorly understood.

Results

Herein the abundance of a selection of 148 transcripts involved in immunosenescence and stress response was compared in total RNA of PBMC of 28 healthy aged probands and 39 aged patients in acute phase of infectious disease (day 2-4 after hospitalization) or in convalescence phase (day 7-10). This study provides a list of 24 differentially abundant transcript species in the acute phase versus healthy aged. For instance, transcripts associated with inflammatory and anti-inflammatory reactions (TNFRSF1A, IL1R1, IL1R2, IL10RB) and with oxidative stress (HMOX1, GPX1, SOD2, PRDX6) were more abundant while those associated with T-cell functions (CD28, CD69, LCK) were less abundant in acute phase. The abundance of seven of these transcripts (CD28, CD69, LCK, CTSD, HMOX1, TNFRSF1A and PRDX6) was already known to be altered in healthy aged probands compared to healthy young ones and was further affected in aged patients in acute phase, compromising an efficient response.

Conclusion

This work provides insights of the state of acute phase response to infections in elderly patients and could explain further the lack of appropriate response in the elderly compared to younger persons.

Ultraviolet radiation and skin aging: roles of reactive oxygen species, inflammation and protease activation, and strategies for prevention of inflammation-induced matrix degradation - a review

Inflammation and the resulting accumulation of reactive oxygen species (ROS) play an important role in the intrinsic and photoaging of human skin in vivo. Environmental insults such as ultraviolet (UV) rays from sun, cigarette smoke exposure and pollutants, and the natural process of aging contribute to the generation of free radicals and ROS that stimulate the inflammatory process in the skin. UV irradiation initiates and activates a complex cascade of biochemical reactions in human skin. In short, UV causes depletion of cellular antioxidants and antioxidant enzymes (SOD, catalase), initiates DNA damage leading to the formation of thymidine dimmers, activates the neuroendocrine system leading to immunosuppression and release of neuroendocrine mediators, and causes increased synthesis and release of pro-inflammatory mediators from a variety of skin cells. The pro-inflammatory mediators increase the permeability of capillaries leading to infiltration and activation of neutrophils and other phagocytic cells into the skin. The net result of all these effects is inflammation and free radical generation (both reactive oxygen and nitrogen species). Furthermore, elastsases and other proteases (cathepsin G) released from neutrophils cause further inflammation, and activation of matrix metalloproteases. The inflammation further activates the transcription of various matrixes degrading metalloproteases, leading to abnormal matrix degradation and accumulation of non-functional matrix components. In addition, the inflammation and ROS cause oxidative damage to cellular proteins, lipids and carbohydrates, which accumulates in the dermal and epidermal compartments, contributing to the aetiology of photoaging. Strategies to prevent photodamage caused by this cascade of reactions initiated by UV include: prevention of UV penetration into skin by physical and chemical sunscreens, prevention/reduction of inflammation using anti-inflammatory compounds (e.g. cyclooxygenase inhibitors, inhibitors of cytokine generation); scavenging and quenching of ROS by antioxidants; inhibition of neutrophil elastase activity to prevent extracellular matrix damage and activation of matrix metalloproteases (MMPs), and inhibition of MMP expression (e.g. by retinoids) and activity (e.g. by natural and synthetic inhibitors).

Molecular and metabolic evidence for mitochondrial defects associated with beta-cell dysfunction in a mouse model of type 2 diabetes

OBJECTIVE The inability of pancreatic beta-cells to appropriately respond to glucose and secrete insulin are primary defects associated with beta-cell failure in type 2 diabetes. Mitochondrial dysfunction has been implicated as a key factor in the development of type 2 diabetes; however, a link between mitochondrial dysfunction and defective insulin secretion is unclear. RESEARCH DESIGN AND METHODS We investigated the changes in islet mitochondrial function and morphology during progression from insulin resistance (3 weeks old), immediately before hyperglycemia (5 weeks old), and after diabetes onset (10 weeks old) in transgenic MKR mice compared with controls. The molecular and protein changes at 10 weeks were determined using microarray and iTRAQ proteomic screens. RESULTS At 3 weeks, MKR mice were hyperinsulinemic but normoglycemic and beta-cells showed negligible mitochondrial or morphological changes. At 5 weeks, MKR islets displayed abrogated hyperpolarization of mitochondrial membrane potential (DeltaPsi(m)), reduced mitochondrial Ca(2+) uptake, slightly enlarged mitochondria, and reduced glucose-stimulated insulin secretion. By 10 weeks, MKR mice were hyperglycemic and hyperinsulinemic and beta-cells contained swollen mitochondria with disordered cristae. beta-Cells displayed impaired stimulus-secretion coupling including reduced hyperpolarization of DeltaPsi(m), impaired Ca(2+)-signaling, and reduced glucose-stimulated ATP/ADP and insulin release. Furthermore, decreased cytochrome c oxidase-dependent oxygen consumption and signs of oxidative stress were observed in diabetic islets. Protein profiling of diabetic islets revealed that 36 mitochondrial proteins were differentially expressed, including inner membrane proteins of the electron transport chain. CONCLUSIONS We provide novel evidence for a critical role of defective mitochondrial oxidative phosphorylation and morphology in the pathology of insulin resistance-induced beta-cell failure.

Transcription profile analysis of vastus lateralis muscle from patients with chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is a disabling condition characterized by unexplained chronic fatigue that impairs normal activities. Many body systems are affected and etiology has not yet been identified. In addition to immunological and psychological aspects, skeletal muscle symptoms are prominent in CFS patients. In an effort to establish which pathways might be involved in the onset and development of muscle symptoms, we used global transcriptome analysis to identify genes that were differentially expressed in the vastus lateralis muscle of female and male CFS patients. We found that the expression of genes that play key roles in mitochondrial function and oxidative balance, including superoxide dismutase 2, were altered, as were genes involved in energy production, muscular trophism and fiber phenotype determination. Importantly, the expression of a gene encoding a component of the nicotinic cholinergic receptor binding site was reduced, suggesting impaired neuromuscular transmission. We argue that these major biological processes could be involved in and/or responsible for the muscle symptoms of CFS.

Pharmacologic concentrations of ascorbic acid cause diverse influence on differential expressions of angiogenic chemokine genes in different hepatocellular carcinoma cell lines

This study was to investigate whether ascorbic acid (AA) at pharmacologic concentration became prooxidant and had the potential to influence the expressions of angiogenic and angiostatic chemokine genes in hepatocellular carcinoma (HCC) cell lines. Influence of low (1 mM) and high (30 mM) pharmacologic concentrations of AA on two HCC cell lines (cell line A, HCC24/KMUH; cell line B, HCC38/KMUH) were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Three angiogenic genes (CCL2, CXCL6, IL8), one angiostatic gene (CXCL10) and two genes related to oxidative stress (SOD2, VNN3) were selected for quantitative RT-PCR study. Both low and high pharmacologic concentrations of AA up-regulated CCL2, CXCL6, IL8, SOD2 and VNN3 genes in cell line A, but down-regulated CCL2 and IL8 genes in cell line B. CXCL6 gene in cell line B was down-regulated by high pharmacologic concentration of AA. CXCL10 gene was up-regulated by low pharmacologic concentration of AA, but was down-regulated by high pharmacologic concentration of AA in both cell lines. Low pharmacologic concentration of AA up-regulated VNN3 gene and high pharmacologic concentration of AA up-regulated SOD2 gene in cell line B. These results indicate that pharmacologic concentration of AA becomes prooxidant to HCC cells and has diverse influence on differential expressions of angiogenic chemokine genes in different HCC cell lines. Differential expressions of CXCL10 gene are determined by the concentrations of AA used. Clinical application of AA in patients with HCC should consider these effects.

Mammalian stanniocalcin-1 activates mitochondrial antioxidant pathways: new paradigms for regulation of macrophages and endothelium

The mammalian homolog of the fish calcium regulatory hormone stanniocalcin-1 (STC1) is ubiquitously expressed and likely functions in an autocrine/paracrine fashion. Mammalian STC1 does not appear to exert significant effects on serum calcium, and its physiological role remains to be determined. In macrophages, STC1 decreases intracellular calcium and cell mobility; attenuates the response to chemoattractants; and diminishes superoxide generation through induction of uncoupling protein-2 (UCP2). In cytokine-treated endothelial cells, STC1 attenuates superoxide generation and the activation of inflammatory pathways [c-Jun NH(2)-terminal kinase (JNK) and NF-kappaB]; maintains the expression of tight junction proteins, preserving the endothelial monolayer seal; and decreases transendothelial migration of leukocytes. Combined, the effects of STC1 on endothelial cells and macrophages predict potent anti-inflammatory action. Indeed, application of the anti-glomerular basement membrane (GBM) glomerulonephritis model to STC1 transgenic mice that display increased expression of STC1 transgene in endothelial cells and macrophages yields renal protection. Our data suggest that STC1 activates antioxidant pathways in endothelial cells and macrophages and displays cytoprotective and anti-inflammatory actions.