NF-κB pathway activators as potential ageing biomarkers: targets for new therapeutic strategies

Age-related neuroinflammation and changes in AKT-GSK-3β and WNT/ β-CATENIN signaling in rat hippocampus

Aging is a multifactorial process associated with an increased susceptibility to neurodegenerative disorders which can be related to chronic inflammation. Chronic inflammation, however, can be characterized by the persistent elevated glucocorticoid (GCs) levels, activation of the proinflammatory transcription factor NF-кB, as well as an increase in cytokines. Interestingly, both NF-кB and cytokines can be even modulated by Glycogen Synthase Kinase 3 beta (GSK-3β) activity, which is a key protein that can intermediate inflammation and metabolism, once it has a critical role in AKT signaling pathway, and can also intermediate WNT/β-CATENIN signaling pathway. The aim of this study was to verify age-related changes in inflammatory status, as well as in the AKT and WNT signaling pathways. Results showed an age-related increase in neuroinflammation as indicated by NF-кB activation, TNF-α and GCs increased levels, a decrease in AKT activation and an increase in GSK-3β activity in both 12- and 24- month old animals. Aging also seems to induce a progressive decrease in canonical WNT/β-CATENIN signaling pathway once there is a decrease in DVL-2 levels and in the transcription of Axin2 gene. Little is known about the DVL-2 regulation as well as its roles in WNT signaling pathway, but for the first time it was suggested that DVL-2 expression can be changed along aging.

The emerging role of Notch pathway in ageing: Focus on the related mechanisms in age-related diseases

Notch signaling is an evolutionarily conserved pathway, which is fundamental for the development of all tissues, organs and systems of human body. Recently, a considerable and still growing number of studies have highlighted the contribution of Notch signaling in various pathological processes of the adult life, such as age-related diseases. In particular, the Notch pathway has emerged as major player in the maintenance of tissue specific homeostasis, through the control of proliferation, migration, phenotypes and functions of tissue cells, as well as in the cross-talk between inflammatory cells and the innate immune system, and in onset of inflammatory age-related diseases. However, until now there is a confounding evidence about the related mechanisms. Here, we discuss mechanisms through which Notch signaling acts in a very complex network of pathways, where it seems to have the crucial role of hub. Thus, we stress the possibility to use Notch pathway, the related molecules and pathways constituting this network, both as innovative (predictive, diagnostic and prognostic) biomarkers and targets for personalised treatments for age-related diseases.

Human Neural Stem Cell Aging Is Counteracted by α-Glycerylphosphorylethanolamine

Neural stem cells (NSCs) represent a subpopulation of cells, located in specific regions of the adult mammalian brain, with the ability of self-renewing and generating neurons and glia. In aged NSCs, modifications in the amount and composition of membrane proteins/lipids, which lead to a reduction in membrane fluidity and cholinergic activities, have been reported. In this respect, molecules that are effective at normalizing the membrane composition and cholinergic signaling could counteract stem cell aging. α-Glycerylphosphorylethanolamine (GPE), a nootropic drug, plays a role in phospholipid biosynthesis and acetylcholine release. Herein, GPE was assayed on human NSC cultures and on hydroxyurea-aged cells. Using cell counting, colorimetric, and fluorimetric analyses, immunoenzymatic assays, and real time PCR experiments, NSC culture proliferation, senescence, reactive oxygen species, and ADP/ATP levels were assessed. Aged NSCs exhibited cellular senescence, decreased proliferation, and an impairment in mitochondrial metabolism. These changes included a substantial induction in the nuclear factor NF-κB, a key inflammatory mediator. GPE cell treatment significantly protected the redox state and functional integrity of mitochondria, and counteracted senescence and NF-κB activation. In conclusion, our data show the beneficial properties of GPE in this model of stem cell aging.

Relationship of protein O-GlcNAcylation with inflammation and immunity

Addition of O-linked N-acetylglucosamine (O-GlcNAc) to the hydroxyl group of serine/threonine residues (O-GlcNAcylation) is a post-translational modification common to multicellular eukaryotes. O-GlcNAc plays an important role in the regulation of many biological processes including, but not limited to, cell cycle progression, transcription, translation, signal transduction, and stress response. Physiologically, it functions as a major stress sensor that inhibits the inflammatory response and cell apoptosis, reduces the amount of protein degradation, and adjusts the body's immunity. In this review, we summarize the current understanding of the physiological significance of O-GlcNAcylation, as well as its correlation with inflammation and immunity.

cAMP/PKA Signaling Pathway Induces Apoptosis by Inhibited NF-κB in Aluminum Chloride-Treated Lymphocytes In Vitro

To explore the apoptosis mechanism in lymphocytes of rats induced by aluminum chloride (AlCl3) by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway, the splenic lymphocytes of rats were cultured and exposed to different concentrations of AlCl3 for 24 h. The final concentrations of AlCl3 (AlCl3 · 6H2O) in supernatant were 0 (control group, CG), 0.3 mmol/L (low-dose group, LG), 0.6 mmol/L (mid-dose group, MG), and 1.2 mmol/L (high-dose group, HG), respectively. Lymphocytes Apoptosis rate, intracellular cAMP content, PKA, survivin, B cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2-associated X protein (Bax) mRNA expressions, and the mRNA and protein expressions of nuclear factor-κ-gene binding (NF-κB, p65) were detected, respectively. The results showed that apoptosis index of lymphocytes, cAMP content in intracellular and PKA mRNA expression were significantly upregulated, whereas NF-κB and survivin mRNA expressions, nuclear NF-κB (p65) protein expression, and the ratio of Bcl-2 and Bax mRNA expression were downregulated in the AlCl3-treated groups compared with those in CG. The results indicated that the activated cAMP/PKA signaling pathway induces apoptosis by inhibited NF-κB in AlCl3-treated lymphocytes in vitro.

Molecular biomarkers for chronological age in animal ecology

The chronological age of an individual animal predicts many of its biological characteristics, and these in turn influence population-level ecological processes. Animal age information can therefore be valuable in ecological research, but many species have no external features that allow age to be reliably determined. Molecular age biomarkers provide a potential solution to this problem. Research in this area of molecular ecology has so far focused on a limited range of age biomarkers. The most commonly tested molecular age biomarker is change in average telomere length, which predicts age well in a small number of species and tissues, but performs poorly in many other situations. Epigenetic regulation of gene expression has recently been shown to cause age-related modifications to DNA and to cause changes in abundance of several RNA types throughout animal lifespans. Age biomarkers based on these epigenetic changes, and other new DNA-based assays, have already been applied to model organisms, humans and a limited number of wild animals. There is clear potential to apply these marker types more widely in ecological studies. For many species, these new approaches will produce age estimates where this was previously impractical. They will also enable age information to be gathered in cross-sectional studies and expand the range of demographic characteristics that can be quantified with molecular methods. We describe the range of molecular age biomarkers that have been investigated to date and suggest approaches for developing the newer marker types as age assays in nonmodel animal species.

Melatonin overcomes gemcitabine resistance in pancreatic ductal adenocarcinoma by abrogating nuclear factor-κB activation

Constitutive activation and gemcitabine induction of nuclear factor-κB (NF-κB) contribute to the aggressive behavior and chemotherapeutic resistance of pancreatic ductal adenocarcinoma (PDAC). Thus, targeting the NF-κB pathway has proven an insurmountable challenge for PDAC therapy. In this study, we investigated whether the inhibition of NF-κB signaling pathway by melatonin might lead to tumor suppression and overcome gemcitabine resistance in pancreatic tumors. Our results showed that melatonin inhibited activities of NF-κB by suppressing IκBα phosphorylation and decreased the expression of NF-κB response genes in MiaPaCa-2, AsPc-1, Panc-28 cells and gemcitabine resistance MiaPaCa-2/GR cells. Moreover, melatonin not only inhibited cell proliferation and invasion in a receptor-independent manner, but also enhanced gemcitabine cytotoxicity at pharmacologic concentrations in these PDAC cells. In vivo, the mice treated with both agents experienced a larger reduction in tumor burden than the single drug-treated groups in an orthotopic xenograft mouse model. Taken together, these results indicate that melatonin inhibits proliferation and invasion of PDAC cells and overcomes gemcitabine resistance of pancreatic tumors through NF-κB inhibition. Our findings therefore provide novel preclinical knowledge about melatonin inhibition of NF-κB in PDAC and suggest that melatonin should be investigated clinically, alone or in combination with gemcitabine for PDAC treatment.

DAMPs, ageing, and cancer: The 'DAMP Hypothesis'

Ageing is a complex and multifactorial process characterized by the accumulation of many forms of damage at the molecular, cellular, and tissue level with advancing age. Ageing increases the risk of the onset of chronic inflammation-associated diseases such as cancer, diabetes, stroke, and neurodegenerative disease. In particular, ageing and cancer share some common origins and hallmarks such as genomic instability, epigenetic alteration, aberrant telomeres, inflammation and immune injury, reprogrammed metabolism, and degradation system impairment (including within the ubiquitin-proteasome system and the autophagic machinery). Recent advances indicate that damage-associated molecular pattern molecules (DAMPs) such as high mobility group box 1, histones, S100, and heat shock proteins play location-dependent roles inside and outside the cell. These provide interaction platforms at molecular levels linked to common hallmarks of ageing and cancer. They can act as inducers, sensors, and mediators of stress through individual plasma membrane receptors, intracellular recognition receptors (e.g., advanced glycosylation end product-specific receptors, AIM2-like receptors, RIG-I-like receptors, and NOD1-like receptors, and toll-like receptors), or following endocytic uptake. Thus, the DAMP Hypothesis is novel and complements other theories that explain the features of ageing. DAMPs represent ideal biomarkers of ageing and provide an attractive target for interventions in ageing and age-associated diseases.

The role of vitamin C in pushing back the boundaries of skin aging: an ultrasonographic approach

Background

Imagistic methods stand as modern, non-invasive, and objective means of assessing the impact of topical cutaneous therapies.

Objective

This study focuses on the evaluation, by high-frequency ultrasound, of the cutaneous changes induced by topical use of a vitamin C complex at facial level.

Methods

A vitamin C-based solution/Placebo moisturizer cream was applied at facial level of 60 healthy female subjects according to a predetermined protocol. Ultrasonographic images (Dermascan C, 20 MHz) were taken from zygomatic level initially, at 40 and 60 days after therapy. The following parameters were assessed for every subject: thickness of the epidermis and dermis (mm), the number of low (LEP), medium (MEP), high echogenic pixels (HEP), and the number of LEP in the upper dermis/lower dermis (LEPs/LEPi).

Results

LEP decreased significantly in all age categories during and after therapy, but especially in the first 2 age intervals, up to the age of 50 (P=0.0001). MEP and HEP, pixel categories that quantify protein synthesis also had an age-dependent evolution in the study, increasing significantly in all age categories but most of all in the first age interval (P=0.002). Our ultrasonographic data suggest that collagen synthesis increased significantly after topical vitamin C therapy, and is responsible for the increase in MEP and HEP and consequent decrease of the LEP.

Conclusion

Our study shows that topically applied vitamin C is highly efficient as a rejuvenation therapy, inducing significant collagen synthesis in all age groups with minimal side effects.

Age-Specific Gene Expression Profiles of Rhesus Monkey Ovaries Detected by Microarray Analysis

The biological function of human ovaries declines with age. To identify the potential molecular changes in ovarian aging, we performed genome-wide gene expression analysis by microarray of ovaries from young, middle-aged, and old rhesus monkeys. Microarray data was validated by quantitative real-time PCR. Results showed that a total of 503 (60 upregulated, 443 downregulated) and 84 (downregulated) genes were differentially expressed in old ovaries compared to young and middle-aged groups, respectively. No difference in gene expression was found between middle-aged and young groups. Differentially expressed genes were mainly enriched in cell and organelle, cellular and physiological process, binding, and catalytic activity. These genes were primarily associated with KEGG pathways of cell cycle, DNA replication and repair, oocyte meiosis and maturation, MAPK, TGF-beta, and p53 signaling pathway. Genes upregulated were involved in aging, defense response, oxidation reduction, and negative regulation of cellular process; genes downregulated have functions in reproduction, cell cycle, DNA and RNA process, macromolecular complex assembly, and positive regulation of macromolecule metabolic process. These findings show that monkey ovary undergoes substantial change in global transcription with age. Gene expression profiles are useful in understanding the mechanisms underlying ovarian aging and age-associated infertility in primates.

Do airborne biogenic chemicals interact with the PI3K/Akt/mTOR cell signalling pathway to benefit human health and wellbeing in rural and coastal environments?

Living and taking recreation in rural and coastal environments promote health and wellbeing, although the causal factors involved are unclear. It has been proposed that such environments provide a counter to the stresses of everyday living, leading to enhanced mental and physical health. Living in natural environments will result in airborne exposure to a wide range of biogenic chemicals through inhalation and ingestion of airborne microbiota and particles. The "biogenics" hypothesis formulated here is that regular exposure to low concentrations of mixtures of natural compounds and toxins in natural environments confers pleiotropic health benefits by inhibiting the activities of interconnected cell signalling systems, particularly PI3K/Akt/mTORC1. When overactive, Akt and mTOR (mTORC1) can lead to many pathological processes including cancers, diabetes, inflammation, immunosuppression, and neurodegenerative diseases. There is a substantial body of evidence that many natural products (i.e., from bacteria, algae, fungi and higher plants) inhibit the activities of these protein kinases. Other mTOR-related interconnected metabolic control "switches" (e.g., PTEN & NF-κB), autophagy and other cytoprotective processes are also affected by natural products. The "biogenics" hypothesis formulated here is that regular intermittent exposure to a mixture of airborne biogenic compounds in natural environments confers pleiotropic health benefits by inhibiting activities of the highly interconnected PI3K/Akt/mTORC1 system. It is proposed that future experimental exposures to biogenic aerosols in animal models coupled with epidemiology, should target the activities of the various kinases in the PI3K/Akt/mTORC1 systems and related physiological processes for selected urban, rural and coastal populations in order to test this hypothesis.

Zinc, aging, and immunosenescence: an overview

Zinc plays an essential role in many biochemical pathways and participates in several cell functions, including the immune response. This review describes the role of zinc in human health, aging, and immunosenescence. Zinc deficiency is frequent in the elderly and leads to changes similar to those that occur in oxidative inflammatory aging (oxi-inflamm-aging) and immunosenescence. The possible benefits of zinc supplementation to enhance immune function are discussed.

Melatonin as a proteasome inhibitor. Is there any clinical evidence?

Proteasome inhibitors and melatonin are both intimately involved in the regulation of major signal transduction proteins including p53, cyclin p27, transcription factor NF-κB, apoptotic factors Bax and Bim, caspase 3, caspase 9, anti-apoptotic factor Bcl-2, TRAIL, NRF2 and transcription factor beta-catenin. The fact that these factors are shared targets of the proteasome inhibitor bortezomib and melatonin suggests the working hypothesis that melatonin is a proteasome inhibitor. Supporting this hypothesis is the fact that melatonin shares with bortezomib a selective pro-apoptotic action in cancer cells. Furthermore, both bortezomib and melatonin increase the sensitivity of human glioma cells to TRAIL-induced apoptosis. Direct evidence for melatonin inhibition of the proteasome was recently found in human renal cancer cells. We raise the issue whether melatonin should be investigated in combination with proteasome inhibitors to reduce toxicity, to reduce drug resistance, and to enhance efficacy. This may be particularly valid for hematological malignancies in which proteasome inhibitors have been shown to be useful. Further studies are necessary to determine whether the actions of melatonin on cellular signaling pathways are due to a direct inhibitory effect on the catalytic core of the proteasome, due to an inhibitory action on the regulatory particle of the proteasome, or due to an indirect effect of melatonin on phosphorylation of signal transducing factors.

Mediterranean diet and healthy ageing: a Sicilian perspective

Traditional Mediterranean diet (MedDiet) is a common dietary pattern characterizing a lifestyle and culture proven to contribute to better health and quality of life in Mediterranean countries. By analyzing the diet of centenarians from the Sicani Mountains and eating habits of inhabitants of Palermo, it is reported that a close adherence to MedDiet is observed in the countryside, whereas in big towns this adherence is not so close. This has an effect on the rates of mortality at old age (and reciprocally longevity) that are lower in the countryside than in big towns. Concerning the health effects of the diet, the low content of animal protein and the low glycaemic index of the Sicilian MedDiet might directly modulate the insulin/IGF-1 and the mTOR pathways, known to be involved in ageing and longevity. In particular, the reduction of animal protein intake may significantly reduce serum IGF-1 concentrations and inhibit mTOR activity with a down-regulation of the signal that leads to the activation of FOXO3A and, consequently, to the transcription of homeostatic genes that favour longevity. The down-regulation of both IGF-1 and mTORC1 also induces an anti-inflammatory effect. In addition to the effects on sensing pathways, many single components of MedDiet are known to have positive effects on health, reducing inflammation, optimizing cholesterol and other important risk factors of age-related diseases. However, a key role is played by polyphenols represented in high amount in the Sicilian MedDiet (in particular in extra virgin olive oil) that can work as hormetins that provide an environmental chemical signature regulating stress resistance pathways such as nuclear factor erythroid 2-related factor 2.

Are the leukocyte telomere length attrition and telomerase activity alteration potential predictor biomarkers for sporadic TAA in aged individuals?

A large variability in occurrence, complications, and age/gender manifestations characterizes individual susceptibility of sporadic thoracic aortic aneurysms (TAA), even in subjects with the same risk factor profiles. The reasons are poorly understood. On the other hand, TAA pathophysiology mechanisms remain unclear than those involved in abdominal aorta aneurysms. However, recent evidence is suggesting a crucial role of biological ageing in inter-individual risk variation of cardiovascular diseases, including sporadic TAA. Biological age rather than chronological age is a better predictor of vascular risk. Relevant assumptions support this concept. In confirming this evidence and our preliminary data, the mean of blood leukocyte telomere length, through use of terminal restriction fragment assay and in blood samples from sporadic TAA patients and controls, was examined. Telomerase activity was also analyzed in two groups. In addition, we verified the weight of genetic inflammatory variants and the major TAA risk factors in telomere/telomerase impairment. Aorta histopathological abnormalities and systemic inflammatory mediators were ultimately correlated with telomere/telomerase impairment. Data obtained demonstrated shorter telomeres and a reduced telomerase activity in TAA patients significantly associated with a genetic inflammatory risk profile, age, gender, smoking, hypertension, a histopathological phenotype, and higher levels of systemic inflammatory mediators than controls. In conclusion, telomere and telomerase activity's detection might be used as predictor biomarkers of sporadic TAA. Their impairment also suggests a strong role of vascular ageing in sporadic TAA, evocated by both environmental and genetic inflammatory factors.

Can the TLR-4-mediated signaling pathway be "a key inflammatory promoter for sporadic TAA"?

Thoracic aorta shows with advancing age various changes and a progressive deterioration in structure and function. As a result, vascular remodeling (VR) and medial degeneration (MD) occur as pathological entities responsible principally for the sporadic TAA onset. Little is known about their genetic, molecular, and cellular mechanisms. Recent evidence is proposing the strong role of a chronic immune/inflammatory process in their evocation and progression. Thus, we evaluated the potential role of Toll like receptor- (TLR-) 4-mediated signaling pathway and its polymorphisms in sporadic TAA. Genetic, immunohistochemical, and biochemical analyses were assessed. Interestingly, the rs4986790 TLR4 polymorphism confers a higher susceptibility for sporadic TAA (OR = 14.4, P = 0.0008) and it represents, together with rs1799752 ACE, rs3918242 MMP-9, and rs2285053 MMP-2 SNPs, an independent sporadic TAA risk factor. In consistency with these data, a significant association was observed between their combined risk genotype and sporadic TAA. Cases bearing this risk genotype showed higher systemic inflammatory mediator levels, significant inflammatory/immune infiltrate, a typical MD phenotype, lower telomere length, and positive correlations with histopatological abnormalities, hypertension, smoking, and ageing. Thus, TLR4 pathway should seem to have a key role in sporadic TAA. It might represent a potential useful tool for preventing and monitoring sporadic TAA and developing personalized treatments.

Microglia change from a reactive to an age-like phenotype with the time in culture

Age-related neurodegenerative diseases have been associated with chronic neuroinflammation and microglia activation. However, cumulative evidence supports that inflammation only occurs at an early stage once microglia change the endogenous characteristics with aging and switch to irresponsive/senescent and dystrophic phenotypes with disease progression. Thus, it will be important to have the means to assess the role of reactive and aged microglia when studying advanced brain neurodegeneration processes and age-associated related disorders. Yet, most studies are done with microglia from neonates since there are no adequate means to isolate degenerating microglia for experimentation. Indeed, only a few studies report microglia isolation from aged animals, using either short-term cultures or high concentrations of mitogens in the medium, which trigger microglia reactivity. The purpose of this study was to develop an experimental process to naturally age microglia after isolation from neonatal mice and to characterize the cultured cells at 2 days in vitro (DIV), 10 DIV, and 16 DIV. We found that 2 DIV (young) microglia had predominant amoeboid morphology and markers of stressed/reactive phenotype. In contrast, 16 DIV (aged) microglia evidenced ramified morphology and increased matrix metalloproteinase (MMP)-2 activation, as well as reduced MMP-9, glutamate release and nuclear factor kappa-B activation, in parallel with decreased expression of Toll-like receptor (TLR)-2 and TLR-4, capacity to migrate and phagocytose. These findings together with the reduced expression of microRNA (miR)-124, and miR-155, decreased autophagy, enhanced senescence associated beta-galactosidase activity and elevated miR-146a expression, are suggestive that 16 DIV cells mainly correspond to irresponsive/senescent microglia. Data indicate that the model represent an opportunity to understand and control microglial aging, as well as to explore strategies to recover microglia surveillance function.

Long-term high-level exercise promotes muscle reinnervation with age

The histologic features of aging muscle suggest that denervation contributes to atrophy, that immobility accelerates the process, and that routine exercise may protect against loss of motor units and muscle tissue. Here, we compared muscle biopsies from sedentary and physically active seniors and found that seniors with a long history of high-level recreational activity up to the time of muscle biopsy had 1) lower loss of muscle strength versus young men (32% loss in physically active vs 51% loss in sedentary seniors); 2) fewer small angulated (denervated) myofibers; 3) a higher percentage of fiber-type groups (reinnervated muscle fibers) that were almost exclusive of the slow type; and 4) sparse normal-size muscle fibers coexpressing fast and slow myosin heavy chains, which is not compatible with exercise-driven muscle-type transformation. The biopsies from the old physically active seniors varied from sparse fiber-type groupings to almost fully transformed muscle, suggesting that coexpressing fibers appear to fill gaps. Altogether, the data show that long-term physical activity promotes reinnervation of muscle fibers and suggest that decades of high-level exercise allow the body to adapt to age-related denervation by saving otherwise lost muscle fibers through selective recruitment to slow motor units. These effects on size and structure of myofibers may delay functional decline in late aging.

Identification of three particular morphological phenotypes in sporadic thoracic aortic aneurysm: phenotype III as sporadic thoracic aortic aneurysm biomarker in aged individuals

Aging has a striking impact on the heart and the vascular system, and particularly on the large elastic arteries (i.e., aorta), resulting in a multitude of changes at different structural and functional levels. As result, medial degeneration (MD) occurs. A characteristic example of MD is sporadic thoracic aortic aneurysm (S-TAA), whose patho-physiological mechanisms remain unclear. In this study, typical MD morphological phenotypes were researched in S-TAA cases and control aorta specimens using histopathological and mainly immunohistochemical analyses. Three phenotypes (I, II, and III) were detected, but the phenotype III was observed. Elevated cystic MD, plurifocal medial apoptosis, and increased metalloproteinase-9 amount characterize it. In addition, it was significantly correlated with the severity of elastic fragmentation, hypertension, and smoking, and particularly with advancing age. Thus, phenotype III might represent the typical MD phenotype associated with S-TAA in old people that have a major risk of aorta rupture and dissection independently on aneurysm diameter. This might permit the assumption that phenotype III with its typical histological abnormalities is an optimal biomarker of rupture and/or dissection in aged individuals and is useful both for applying different surgical approaches and providing appropriate surgical indications.