ROS, Cell Senescence, and Novel Molecular Mechanisms in Aging and Age-Related Diseases. Oxid Med Cell Longev. 2016;2016:3565127. [PMID: 27247702 PMCID: PMC4877482 DOI: 10.1155/2016/3565127]

Antioxidant and Oxidative Stress: A Mutual Interplay in Age-Related Diseases

Aging is the progressive loss of organ and tissue function over time. Growing older is positively linked to cognitive and biological degeneration such as physical frailty, psychological impairment, and cognitive decline. Oxidative stress is considered as an imbalance between pro- and antioxidant species, which results in molecular and cellular damage. Oxidative stress plays a crucial role in the development of age-related diseases. Emerging research evidence has suggested that antioxidant can control the autoxidation by interrupting the propagation of free radicals or by inhibiting the formation of free radicals and subsequently reduce oxidative stress, improve immune function, and increase healthy longevity. Indeed, oxidation damage is highly dependent on the inherited or acquired defects in enzymes involved in the redox-mediated signaling pathways. Therefore, the role of molecules with antioxidant activity that promote healthy aging and counteract oxidative stress is worth to discuss further. Of particular interest in this article, we highlighted the molecular mechanisms of antioxidants involved in the prevention of age-related diseases. Taken together, a better understanding of the role of antioxidants involved in redox modulation of inflammation would provide a useful approach for potential interventions, and subsequently promoting healthy longevity.

Single copy/knock-in models of ALS SOD1 in C. elegans suggest loss and gain of function have different contributions to cholinergic and glutamatergic neurodegeneration

Mutations in Cu/Zn superoxide dismutase 1 (SOD1) lead to Amyotrophic Lateral Sclerosis (ALS), a neurodegenerative disease that disproportionately affects glutamatergic and cholinergic motor neurons. Previous work with SOD1 overexpression models supports a role for SOD1 toxic gain of function in ALS pathogenesis. However, the impact of SOD1 loss of function in ALS cannot be directly examined in overexpression models. In addition, overexpression may obscure the contribution of SOD1 loss of function in the degeneration of different neuronal populations. Here, we report the first single-copy, ALS knock-in models in C. elegans generated by transposon- or CRISPR/Cas9- mediated genome editing of the endogenous sod-1 gene. Introduction of ALS patient amino acid changes A4V, H71Y, L84V, G85R or G93A into the C. elegans sod-1 gene yielded single-copy/knock-in ALS SOD1 models. These differ from previously reported overexpression models in multiple assays. In single-copy/knock-in models, we observed differential impact of sod-1 ALS alleles on glutamatergic and cholinergic neurodegeneration. A4V, H71Y, G85R, and G93A animals showed increased SOD1 protein accumulation and oxidative stress induced degeneration, consistent with a toxic gain of function in cholinergic motor neurons. By contrast, H71Y, L84V, and G85R lead to glutamatergic neuron degeneration due to sod-1 loss of function after oxidative stress. However, dopaminergic and serotonergic neuronal populations were spared in single-copy ALS models, suggesting a neuronal-subtype specificity previously not reported in invertebrate ALS SOD1 models. Combined, these results suggest that knock-in models may reproduce the neurotransmitter-type specificity of ALS and that both SOD1 loss and gain of toxic function differentially contribute to ALS pathogenesis in different neuronal populations.

In all SOD1 ALS patients, cholinergic spinal motor neurons degenerate, but degeneration of cortical glutamatergic neurons is less common. Despite decades of work, it remains unclear why some disease alleles (e.g. A4V) primarily affect cholinergic spinal neurons, while other alleles affect both cholinergic and glutamatergic neurons. New genome editing techniques allowed us to create the first C. elegans knock-in/single-copy models for SOD1 ALS by directly editing the C. elegans sod-1 gene to recreate SOD1 amino acid changes that cause ALS in patients. These new models are complementary to previously described overexpression models, which revealed mutant SOD1 toxic gain of function properties. By contrast, in the new C. elegans knock-in models, we find that both loss and gain of sod-1 function contribute to neurodegeneration. C. elegans cholinergic motor neuron loss is primarily driven by toxic gain of function, but glutamatergic neuron loss is primarily driven by loss of function. Only cholinergic and glutamatergic neurons degenerate in C. elegans knock-in models; dopaminergic, serotoninergic and GABAergic neurons do not. This pattern of neuronal loss is reminiscent of the pattern of neuronal loss seen in SOD1 ALS patients. Strikingly, in the C. elegans A4V model, only cholinergic neurons are lost. Our results suggest that an underlying premise of the ALS field–that identical pathological mechanisms lead to degeneration of cholinergic and glutamatergic neurons–should be reconsidered. Mechanisms that predominantly drive glutamatergic and cholinergic neuron degeneration in ALS may not be identical.

The Apoptosis Effect on Liver Cancer Cells of Gold Nanoparticles Modified with Lithocholic Acid

Functionalized gold nanoparticles (AuNPs) have widely applied in many fields, due to their good biocompatibility, a long drug half-life, and their bioactivity is related to their size and the modified ligands on their surface. Here, we synthesized the AuNPs capped with ligands that possess polyethylene glycol (PEG) and lithocholic acid (LCA) linked by carboxyl groups (AuNP@MPA-PEG-LCA). Our cytotoxicity results indicated that AuNP@MPA-PEG-LCA have better cell selectivity; in other words, it could inhibit the growth of multiple liver cancer cells more effectively than other cancer cells and normal cells. Apoptosis plays a role in AuNP@MPA-PEG-LCA inhibition cell proliferation, which was convincingly proved by some apoptotic index experiments, such as nuclear staining, annexin V-FITC, mitochondrial membrane potential (MMP) analysis, and AO/EB staining experiments. The most potent AuNP@MPA-PEG-LCA were confirmed to efficiently induce apoptosis through a reactive oxygen species (ROS) mediating mitochondrial dysfunction. And AuNP@MPA-PEG-LCA could be more effective in promoting programmed cell death of liver cancer cells.

Sumoylation-deficient Prdx6 repairs aberrant Sumoylation-mediated Sp1 dysregulation-dependent Prdx6 repression and cell injury in aging and oxidative stress

Progressive deterioration of antioxidant response in aging is a major culprit in the initiation of age-related pathobiology induced by oxidative stress. We previously reported that oxidative stress leads to a marked reduction in transcription factor Sp1 and its mediated Prdx6 expression in lens epithelial cells (LECs) leading to cell death. Herein, we examined how Sp1 activity goes awry during oxidative stress/aging, and whether it is remediable. We found that Sp1 is hyper-Sumoylated at lysine (K) 16 residue in aging LECs. DNA binding and promoter assays revealed, in aging and oxidative stress, a significant reduction in Sp1 overall binding, and specifically to Prdx6 promoter. Expression/overexpression assay revealed that the observed reduction in Sp1-DNA binding activity was connected to its hyper-Sumoylation due to increased reactive oxygen species (ROS) and Sumo1 levels, and reduced levels of Senp1, Prdx6 and Sp1. Mutagenesis of Sp1 at K16R (arginine) residue restored steady-state, and improved Sp1-DNA binding activity and transactivation potential. Extrinsic expression of Sp1K16R increased cell survival and reduced ROS levels by upregulating Prdx6 expression in LECs under aging/oxidative stress, demonstrating that Sp1K16R escapes the aberrant Sumoylation processes. Intriguingly, the deleterious processes are reversible by the delivery of Sumoylation-deficient Prdx6, an antioxidant, which would be a candidate molecule to restrict aging pathobiology.

Ginsenoside Rg1 attenuates liver injury induced by D-galactose in mice

The present study investigated the effect and underlying mechanisms of ginsenoside Rg1 (Rg1) in attenuating subacute liver injury induced by D-galactose (D-gal) in mice. Specific Pathogen Free (SPF) male C57BL/6J mice were randomly divided into 3 groups: i) D-gal-administration group (D-gal group), where the mice were intraperitoneally administrated with D-gal (120 mg/kg/day for 42 days); ii) D-gal + Rg1 group where the mice were treated with 120 mg/kg/day D-gal for 42 days and with Rg1 at a dose of 20 mg/kg/day for 35 days. The first dose of Rg1 was administered on the 8th day of treatment with D-gal; and iii) the normal control group, where the mice were injected with an equal volume of saline for 42 days. The day following the final injections in all groups, peripheral blood was collected and serum was prepared to measure the contents of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBiL), advanced glycation end products (AGEs) and 8-hydroxy-2 deoxyguanosine (8-OH-dG). Liver tissue homogenates were prepared to measure the contents of malondialdehyde (MDA) and glutathione (GSH), and the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). Paraffin section were prepared to observe the microscopic structure of the liver. Transmission electron microscopy was used to observe the ultrastructure of hepatocytes. Frozen section were prepared and stained with senescence-associated β-galactosidase to detect the relative optical density value of senescence-associated markers. Compared with the D-gal group, the contents of AST, ALT, TBiL, AGEs and MDA significantly decreased in the D-gal + Rg1 group, while the activities of SOD and GSH-Px markedly increased, and liver injury and degenerative alterations of hepatocytes were reduced. Administration of Rg1 induced a protective effect on D-gal-induced liver injury in mice by inhibiting the oxidative stress, reducing DNA damage and decreasing the AGE content.

[Antioxidant and anti-inflammatory modulation of exercise during aging]

Aging is characterised by a gradual loss of the functional reserve. This, along with the fostering of sedentary habits and the increase in risk factors, causes a deterioration of antioxidant defences and an increase of the circulatory levels of inflammatory and oxidative markers, boosting a low-rate chronic inflammation, defined as inflamm-aging. This phenomenon is present in the aetiopathology of chronic diseases, as well as in cognitive deterioration cases associated with aging. The objective of this review is to describe the modulation of antioxidant and anti-inflammatory effects of physical exercise of moderate intensity and volume in the elderly. Evidence of its effectiveness as a non-pharmacological resource is presented, which decreases some deleterious effects of aging. This is mainly due to its neuroprotective action, the increase in circulating anti-inflammatory markers, and the improvement of antioxidant defence derived from its practice.

Astaxanthin-Rich Haematococcus pluvialis Algal Hepatic Modulation in D-Galactose-Induced Aging in Rats: Role of Nrf2

Purpose: Aging is associated with hepatic morphological and physiological deterioration due to the accumulation of endogenous and exogenous free radicals and the resultant oxidative stress. The present study aims to investigate the effect of Haematococcus pluvialis microalgae on hepatic changes associated with D-galactose (D-Gal)-induced aging in rats.

Methods: Aging was induced in rats by daily intraperitoneal injection of D-Gal (200 mg/kg/day) for eight consecutive weeks. D-Gal-injected rats were treated by astaxanthin (ATX)-rich H. pluvialis biomass, its carotenoid and polar fractions for two weeks. Twenty four hours after the last dose, blood samples were collected and the liver tissues were isolated for further biochemical and histopathological examinations.

Results: D-Gal induced aging was associated with an elevation in serum liver function parameters, hepatic oxidative stress biomarkers viz., catalase (CAT), glutathione transferase (GST) and myeloperoxidase (MPO), as well as decreased expression of nuclear factor like-2 (Nrf2). Moreover, induction of aging exhibited an elevation of hepatic inflammatory cytokine; interleukin-6 (IL-6) and its modulator; nuclear factor Kappa B (NF-KB). However, treatment of D-Gal injected rats with ATX-rich H. pluvialis restored the serum liver function parameters as well as hepatic CAT, GST and MPO levels with an elevated expression of Nrf2. Treatment with ATX-rich H. pluvialis was also accompanied with a decrease in hepatic levels of NF-KB and IL-6. Histopathological examination emphasized all the previous results. Similarly, all trans-astaxanthin showed high affinity towards Nrf2 with -7.93 kcal/mol estimated free energy of binding as well as moderate affinities towards IL-6 and NF-KB through a docking study.

Conclusion: ATX-rich H. pluvialis showed beneficial effects by ameliorating the hepatic changes associated with D-Gal induced aging in rats due to its modulatory role of the Nrf2/Keap pathway.

Oxidative stress-induced miRNAs modulate AKT signaling and promote cellular senescence in uterine leiomyoma

Uterine leiomyomas (ULM) grow under high oxidative stress due to a hypoxic microenvironment and defects in redox metabolism. AKT is one major pathway activated by reactive oxygen species (ROS) that maintains ULM growth and survival. We previously reported that AKT inactivated by AKT inhibitors can significantly induce cellular senescence in ULM cells. Since some miRNAs are induced by AKT inhibitors in an ROS-dependent manner, we proposed that these miRNAs may modulate AKT function and cellular senescence in ULM. We therefore established ex vivo models of a three-dimensional ULM spheroid culture system to study the role of miRNAs in cellular senescence. Four miRNAs, miR-29b, miR-181a, miR-182, and miR-200c, were found to induce cellular senescence in primary ULM and myometrium spheroid cultures when stably overexpressed. miR-181a and miR-182 were found to repress AKT3 and CCND2, respectively. Correspondingly, RNAi of AKT3 or CCND2 also induced cellular senescence and G0/G1 arrest. Thus, miR-181a and miR-182 may drive cellular senescence in ULM by repressing AKT3 and CCND2 activity, respectively. We further demonstrated that senescent ULM cells can be effectively removed by BH3 mimetic ABT263, which provides a new therapeutic venue for the treatment of ULM. Our findings suggest that miRNAs are potent modulators in regulating the ROS-AKT-cell cycle axis in uterine leiomyoma.

KEY MESSAGES

A subset of oxidative stress-induced miRNAs is involved in AKT signaling in uterine leiomyoma. Overexpression of miR-181a and miR-182 resulted in cellular senescence in leiomyoma through repression of AKT3 and CCND2, respectively. Silencing of AKT3 and CCND2 drives leiomyoma cell into senescence and cycle arrest. Application of our newly developed 3D leiomyoma spheroids can provide a quick and reliable ex vivo model for cytopathologic and functional analysis. BH3 mimetics can effectively reduce the viability of miRNA-mediated senescent cells in leiomyoma.

Oxidation resistance 1 is a novel senolytic target

The selective depletion of senescent cells (SCs) by small molecules, termed senolytic agents, is a promising therapeutic approach for treating age-related diseases and chemotherapy- and radiotherapy-induced side effects. Piperlongumine (PL) was recently identified as a novel senolytic agent. However, its mechanism of action and molecular targets in SCs was unknown and thus was investigated. Specifically, we used a PL-based chemical probe to pull-down PL-binding proteins from live cells and then mass spectrometry-based proteomic analysis to identify potential molecular targets of PL in SCs. One prominent target was oxidation resistance 1 (OXR1), an important antioxidant protein that regulates the expression of a variety of antioxidant enzymes. We found that OXR1 was upregulated in senescent human WI38 fibroblasts. PL bound to OXR1 directly and induced its degradation through the ubiquitin-proteasome system in an SC-specific manner. The knockdown of OXR1 expression by RNA interference significantly increased the production of reactive oxygen species in SCs in conjunction with the downregulation of antioxidant enzymes such as heme oxygenase 1, glutathione peroxidase 2, and catalase, but these effects were much less significant when OXR1 was knocked down in non-SCs. More importantly, knocking down OXR1 selectively induced apoptosis in SCs and sensitized the cells to oxidative stress caused by hydrogen peroxide. These findings provide new insights into the mechanism by which SCs are highly resistant to oxidative stress and suggest that OXR1 is a novel senolytic target that can be further exploited for the development of new senolytic agents.

The Role of Na/K-ATPase Signaling in Oxidative Stress Related to Aging: Implications in Obesity and Cardiovascular Disease

Aging has been associated with a series of pathophysiological processes causing general decline in the overall health of the afflicted population. The cumulative line of evidence suggests an important role of oxidative stress in the development and progression of the aging process and metabolic abnormalities, exacerbating adipocyte dysfunction, cardiovascular diseases, and associated complications at the same time. In recent years, robust have established the implication of Na/K-ATPase signaling in causing oxidative stress and alterations in cellular mechanisms, in addition to its distinct pumping function. Understanding the underlying molecular mechanisms and exploring the possible sources of pro-oxidants may allow for developing therapeutic targets in these processes and formulate novel intervention strategies for patients susceptible to aging and associated complications, such as obesity and cardiovascular disease. The attenuation of oxidative stress with targeted treatment options can improve patient outcomes and significantly reduce economic burden.

Hydrogen alleviates cellular senescence via regulation of ROS/p53/p21 pathway in bone marrow-derived mesenchymal stem cells in vivo

Senescence has become a hot point issue in recent decades and requires urgent attention. As a novel and effective antioxidant, hydrogen has been proved to alleviate cellular senescence in endothelial cells in vitro. However, the effects and mechanisms of hydrogen on senescence in vivo are still unclear. In the present study, 12-month-old Sprague Dawley (SD) rats were intraperitoneal administration of hydrogen-rich saline (HRS, 10 ml/kg). Subsequently, bone marrow-derived stem cells (BMSCs) were harvested for the detection of hydrogen antisenescence effects and mechanisms. The results showed that the number of senescence-associated β-galactosidase (SA-β-Gal) positive cells was reduced in BMSCs from rats treated with HRS. BMSCs in rats treated with HRS possessed a better proliferation ability, showed more effectively tri-lineage differentiation potential, and had less percentage of cells in G1 cell cycle arrest than the control cells. Additionally, HRS administration inhibited the production of intracellular reactive oxygen species (ROS) and decreased the expression of senescence-related proteins p53 and p21. Our results revealed that hydrogen could alleviate cellular senescence in vivo. And the underlying mechanism of antisenescence effects of hydrogen in BMSCs was via the ROS/p53/p21 signaling pathway. Thus, hydrogen could be a new and convenient strategy for alleviating senescence and for therapy of age-related diseases.

Klotho protects human monocytes from LPS-induced immune impairment associated with immunosenescent-like phenotype

In this study, we provide a new evidence on immunosenescent-like phenotype induction in low density monocytes due to the long-term treatment with lipopolysaccharide (LPS). We show that LPS caused oxidative and nitrosative stress through zinc downregulation and calcium accumulation. In turn, increased amounts of ROS/RNS and pro-inflammatory cytokines TNFα, IL-1β, IL-6 led to the irreversible DNA damage, persistent DDR activation, proliferation inhibition, reduction in cell growth and immune impairment. Furthermore, we provide evidence that klotho reduced levels of ROS/RNS and pro-inflammatory cytokines as well as upregulated secretion of anti-inflammatory IL-10 in LPS-treated monocytes, thus the observed DNA damage was less severe, promptly and properly fixed and cells quickly resumed normal proliferation and maintained their immune functionality. Therefore, klotho protein could be considered as a protective factor against immunosenescent-like phenotype in monocytes an issue relevant to many immune disorders.

Coenzyme Q10 Prevents Senescence and Dysfunction Caused by Oxidative Stress in Vascular Endothelial Cells

Oxidative damage in endothelial cells is proposed to play an important role in endothelial dysfunction and atherogenesis. We previously reported that the reduced form of coenzyme Q10 (CoQ₁₀H₂) effectively inhibits oxidative stress and decelerates senescence in senescence-accelerated mice. Here, we treated human umbilical vein endothelial cells (HUVECs) with H₂O₂ and investigated the protective effect of CoQ₁₀H₂ against senescence, oxidative damage, and reduction in cellular functions. We found that CoQ₁₀H₂ markedly reduced the number of senescence-associated β-galactosidase-positive cells and suppressed the expression of senescence-associated secretory phenotype-associated genes in H₂O₂-treated HUVECs. Furthermore, CoQ₁₀H₂ suppressed the generation of intracellular reactive oxygen species (ROS) but promoted NO production that was accompanied by increased eNOS expression. CoQ₁₀H₂ prevented apoptosis and reductions in mitochondrial function and reduced migration and tube formation activity of H₂O₂-treated cells. The present study indicated that CoQ₁₀H₂ protects endothelial cells against senescence by promoting mitochondrial function and thus could delay vascular aging.

The Na/K-ATPase Oxidant Amplification Loop Regulates Aging

As aging involves oxidant injury, we examined the role of the recently described Na/K-ATPase oxidant amplification loop (NKAL). First, C57Bl6 old mice were given a western diet to stimulate oxidant injury or pNaKtide to antagonize the NKAL. The western diet accelerated functional and morphological evidence for aging whereas pNaKtide attenuated these changes. Next, human dermal fibroblasts (HDFs) were exposed to different types of oxidant stress in vitro each of which increased expression of senescence markers, cell-injury, and apoptosis as well as stimulated the NKAL. Further stimulation of the NKAL with ouabain augmented cellular senescence whereas treatment with pNaKtide attenuated it. Although N-Acetyl Cysteine and Vitamin E also ameliorated overall oxidant stress to a similar degree as pNaKtide, the pNaKtide produced protection against senescence that was substantially greater than that seen with either antioxidant. In particular, pNaKtide appeared to specifically ameliorate nuclear oxidant stress to a greater degree. These data demonstrate that the NKAL is intimately involved in the aging process and may serve as a target for anti-aging interventions.

Activating the PGC-1α/TERT Pathway by Catalpol Ameliorates Atherosclerosis via Modulating ROS Production, DNA Damage, and Telomere Function: Implications on Mitochondria and Telomere Link

Catalpol, an iridoid glucoside, has been found present in large quantities in the root of Rehmannia glutinosa L. and showed a strong antioxidant capacity in the previous study. In the present work, the protective effect of catalpol against AS via inhibiting oxidative stress, DNA damage, and telomere shortening was found in LDLr^-/- mice. This study also shows that activation of the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α)/telomerase reverse transcriptase (TERT) pathway, which is the new link between mitochondria and telomere, was involved in the protective effects of catalpol. Further, by using PGC-1α or TERT siRNA in oxLDL-treated macrophages, it is proved that catalpol reduced oxidative stress, telomere function, and related DNA damage at least partly through activating the PGC-1α/TERT pathway. Moreover, dual luciferase activity assay-validated catalpol directly enhanced PGC-1α promoter activity. In conclusion, our study revealed that the PGC-1α/TERT pathway might be a possible therapeutic target in AS and catalpol has highly favorable characteristics for the treatment of AS via modulating this pathway.

MicroRNAs mediate the senescence-associated decline of NRF2 in endothelial cells

Oxidative stress predisposes to several aging-associated diseases, such as cardiovascular diseases and cancer. In aging, increase in the production of reactive oxygen species is typically accompanied with a decline in adaptive stress responses to oxidative stress. The decline is primarily due to a decrease in antioxidant production. Nuclear factor E2-Related Factor 2 (NRF2) is a key transcription factor regulating oxidative and electrophilic stress responses, but it has also been shown to play a role in the regulation of cell metabolism. NRF2 expression declines in aging, but the mechanisms remain unclear. In this study, we show that microRNAs (miRNAs) that are abundant in old endothelial cells decrease NRF2 expression by direct targeting of NRF2 mRNA. The effect is reversed by miRNA inhibition. The senescence-associated downregulation of NRF2 decreases endothelial glycolytic activity and stress tolerance both of which are restored after reinstating NRF2. Manipulation of the senescence-associated miRNA levels affects the glycolytic activity and stress tolerance consistently with the NRF2 results. We conclude that senescence-associated miRNAs are involved in the decline of NRF2 expression, thus contributing to the repression of adaptive responses during cell senescence.

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A post-transcriptional mechanism for NRF2 downregulation in aging is proposed.

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The mechanism implicates senescence-associated miRNA alterations in NRF2 decline.

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Inhibition of senescence-associated miRNA function increases NRF2 expression in old cells.

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Upregulation of NRF2 increases cell viability.

Drosophila Voltage-Gated Calcium Channel α1-Subunits Regulate Cardiac Function in the Aging Heart

Ion channels maintain numerous physiological functions and regulate signaling pathways. They are the key targets for cellular reactive oxygen species (ROS), acting as signaling switches between ROS and ionic homeostasis. We have carried out a paraquat (PQ) screen in Drosophila to identify ion channels regulating the ROS handling and survival in Drosophila melanogaster. Our screen has revealed that α1-subunits (D-type, T-type, and cacophony) of voltage-gated calcium channels (VGCCs) handle PQ-mediated ROS stress differentially in a gender-based manner. Since ROS are also involved in determining the lifespan, we discovered that the absence of T-type and cacophony decreased the lifespan while the absence of D-type maintained a similar lifespan to that of the wild-type strain. VGCCs are also responsible for electrical signaling in cardiac cells. The cardiac function of each mutant was evaluated through optical coherence tomography (OCT), which revealed that α1-subunits of VGCCs are essential in maintaining cardiac rhythmicity and cardiac function in an age-dependent manner. Our results establish specific roles of α1-subunits of VGCCs in the functioning of the aging heart.

Fibroblast senescence in the pathology of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing interstitial pneumonia of unknown cause with a median survival of only three years. Little is known about the mechanisms that precede the excessive collagen deposition seen in IPF, but cellular senescence has been strongly implicated in disease pathology. Senescence is a state of irreversible cell-cycle arrest accompanied by an abnormal secretory profile and is thought to play a critical role in both development and wound repair. Normally, once a senescent cell has contributed to wound repair, it is promptly removed from the environment via infiltrating immune cells. However, if immune clearance fails, the persistence of senescent cells is thought to drive disease pathology through their altered secretory profile. One of the major cell types involved in wound healing is fibroblasts, and senescent fibroblasts have been identified in the lungs of patients with IPF and in fibroblast cultures from IPF lungs. The question of what is driving abnormally high numbers of fibroblasts into senescence remains unanswered. The transcription factor signal transducer and activator of transcription 3 (STAT3) plays a role in a myriad of processes, including cell-cycle progression, gene transcription, as well as mitochondrial respiration, all of which are dysregulated during senescence. Activation of STAT3 has previously been shown to correlate with IPF progression and therefore is a potential molecular target to modify early-stage senescence and restore normal fibroblast function. This review summarizes what is presently known about fibroblast senescence in IPF and how STAT3 may contribute to this phenotype.

The role of the cell-matrix interface in aging and its interaction with the renin-angiotensin system in the aged vasculature

The extracellular matrix (ECM) is an intricate network that provides structural and anchoring support to cells in order to stabilize cell morphology and tissue architecture. The ECM also controls many aspects of the cell's dynamic behavior and fate through its ongoing, bidirectional interaction with cells. These interactions between the cell and components of the surrounding ECM are implicated in several biological processes, including development and adult tissue repair in response to injury, throughout the lifespan of multiple species. The present review gives an overview of the growing evidence that cell-matrix interactions play a pivotal role in the aging process. The focus of the first part of the article is on recent studies using cell-derived decellularized ECM, which strongly suggest that age-related changes in the ECM induce cellular senescence, a well-recognized hallmark of aging. This is followed by a review of findings from genetic studies indicating that changes in genes involved in cell-ECM adhesion and matrix-mediated intracellular signaling cascades affect longevity. Finally, mention is made of novel data proposing an intricate interplay between cell-matrix interactions and the renin-angiotensin system that may have a significant impact on mammalian arterial stiffness with age.

IGFBP-3 plays an important role in senescence as an aging marker

Aging study requires aging markers to measure the degree of aging process. The aging markers such as senescence associated-β-galactosidase (SA-β-gal), lipofuscin, telomere, p53 and p16 have been known in aging study until now. Therefore, we investigated the role of genes and proteins related to aging in young, senescent and H₂O₂-induced old cells to develop a novel aging marker involved in aging mechanism. After cellular aging was compared in young, senescent and H₂O₂-induced old cells using SA-β-galactosidase staining assay, the expression level of genes and proteins in senescent and H₂O₂-induced old cells were compared and analyzed with those of young cells using RT-PCR, western blot and immunofluorescence staining. First of all, the senescent cells and the cells aged by H₂O₂ showed higher level of SA-β-galactosidase staining than young cells. In particular, the expression level of IGFBP-3 was decreased in senescent and H₂O₂-induced old cells compared with young cells. Moreover, the senescent and H2O2-induced old cells showed higher expression levels of p-PI3K, Akt-1, p-mTOR, p-FoxO1 and FoxO1 than young cells. Furthermore, the expression levels of p300, Ac-p53, p53, p-p21 and p16 were significantly increased in senescent and H₂O₂-induced cells compared to young cells. However, the expression level of SIRT-1 was decreased in senescent and H₂O₂-induced old cells compared to young cells. In conclusion, IGFBP-3 up-regulates PI3K/Akt/mTOR signaling pathway and down-regulates autophagy during cell aging. These results suggest that IGFBP-3 could play a key role in aging study as an important aging marker.

Targeting Oxidatively Induced DNA Damage Response in Cancer: Opportunities for Novel Cancer Therapies

Cancer is a death cause in economically developed countries that results growing also in developing countries. Improved outcome through targeted interventions faces the scarce selectivity of the therapies and the development of resistance to them that compromise the therapeutic effects. Genomic instability is a typical cancer hallmark due to DNA damage by genetic mutations, reactive oxygen and nitrogen species, ionizing radiation, and chemotherapeutic agents. DNA lesions can induce and/or support various diseases, including cancer. The DNA damage response (DDR) is a crucial signaling-transduction network that promotes cell cycle arrest or cell death to repair DNA lesions. DDR dysregulation favors tumor growth as downregulated or defective DDR generates genomic instability, while upregulated DDR may confer treatment resistance. Redox homeostasis deeply and capillary affects DDR as ROS activate/inhibit proteins and enzymes integral to DDR both in healthy and cancer cells, although by different routes. DDR regulation through modulating ROS homeostasis is under investigation as anticancer opportunity, also in combination with other treatments since ROS affect DDR differently in the patients during cancer development and treatment. Here, we highlight ROS-sensitive proteins whose regulation in oxidatively induced DDR might allow for selective strategies against cancer that are better tailored to the patients.

The Good, the Bad, and the Ugly of ROS: New Insights on Aging and Aging-Related Diseases from Eukaryotic and Prokaryotic Model Organisms

Aging is associated with the accumulation of cellular damage over the course of a lifetime. This process is promoted in large part by reactive oxygen species (ROS) generated via cellular metabolic and respiratory pathways. Pharmacological, nonpharmacological, and genetic interventions have been used to target cellular and mitochondrial networks in an effort to decipher aging and age-related disorders. While ROS historically have been viewed as a detrimental byproduct of normal metabolism and associated with several pathologies, recent research has revealed a more complex and beneficial role of ROS in regulating metabolism, development, and lifespan. In this review, we summarize the recent advances in ROS research, focusing on both the beneficial and harmful roles of ROS, many of which are conserved across species from bacteria to humans, in various aspects of cellular physiology. These studies provide a new context for our understanding of the parts ROS play in health and disease. Moreover, we highlight the utility of bacterial models to elucidate the molecular pathways by which ROS mediate aging and aging-related diseases.

Targeting Mitochondria to Counteract Age-Related Cellular Dysfunction

Senescence is related to the loss of cellular homeostasis and functions, which leads to a progressive decline in physiological ability and to aging-associated diseases. Since mitochondria are essential to energy supply, cell differentiation, cell cycle control, intracellular signaling and Ca²⁺ sequestration, fine-tuning mitochondrial activity appropriately, is a tightrope walk during aging. For instance, the mitochondrial oxidative phosphorylation (OXPHOS) ensures a supply of adenosine triphosphate (ATP), but is also the main source of potentially harmful levels of reactive oxygen species (ROS). Moreover, mitochondrial function is strongly linked to mitochondrial Ca²⁺ homeostasis and mitochondrial shape, which undergo various alterations during aging. Since mitochondria play such a critical role in an organism’s process of aging, they also offer promising targets for manipulation of senescent cellular functions. Accordingly, interventions delaying the onset of age-associated disorders involve the manipulation of mitochondrial function, including caloric restriction (CR) or exercise, as well as drugs, such as metformin, aspirin, and polyphenols. In this review, we discuss mitochondria’s role in and impact on cellular aging and their potential to serve as a target for therapeutic interventions against age-related cellular dysfunction.

Biocompatibility of new materials based on nano-structured nitinol with titanium and tantalum composite surface layers: experimental analysis in vitro and in vivo

A technology for obtaining materials from nanostructured nitinol with titanium- or tantalum-enriched surface layers was developed. Surface layers enriched with titanium or tantalum were shown to provide a decrease in the formation of reactive oxygen species and long-lived protein radicals in comparison to untreated nitinol. It was determined that human peripheral vessel myofibroblasts and human bone marrow mesenchymal stromal cells grown on nitinol bases coated with titanium or tantalum-enriched surface layers exhibit a nearly two times higher mitotic index. Response to implantation of pure nitinol, as well as nano-structure nitinol with titanium or tantalum-enriched surface layers, was expressed though formation of a mature uniform fibrous capsule peripherally to the fragment. The thickness of this capsule in the group of animals subjected to implantation of pure nitinol was 1.5 and 3.0-fold greater than that of the capsule in the groups implanted with nitinol fragments with titanium- or tantalum-enriched layers. No signs of calcinosis in the tissues surrounding implants with coatings were observed. The nature and structure of the formed capsules testify bioinertia of the implanted samples. It was shown that the morphology and composition of the surface of metal samples does not alter following biological tests. The obtained results indicate that nano-structure nitinol with titanium or tantalum enriched surface layers is a biocompatible material potentially suitable for medical applications.

Microenvironment-Cell Nucleus Relationship in the Context of Oxidative Stress

The microenvironment is a source of reactive oxygen species (ROS) that influence cell phenotype and tissue homeostasis. The impact of ROS on redox pathways as well as directly on epigenetic mechanisms and the DNA illustrate communication with the cell nucleus. Changes in gene transcription related to redox conditions also influence the content and structure of the extracellular matrix. However, the importance of microenvironmental ROS for normal progression through life and disease development still needs to be thoroughly understood. We illustrate how different ROS concentration levels trigger various intracellular pathways linked to nuclear functions and determine processes necessary for the differentiation of stem cells. The abnormal predominance of ROS that leads to oxidative stress is emphasized in light of its impact on aging and diseases related to aging. These phenomena are discussed in the context of the possible contribution of extracellular ROS via direct diffusion into cells responsible for organ function, but also via an impact on stromal cells that triggers extracellular modifications and influences mechanotransduction. Finally, we argue that organs-on-a-chip with controlled microenvironmental conditions can help thoroughly grasp whether ROS production is readily a cause or a consequence of certain disorders, and better understand the concentration levels of extracellular ROS that are necessary to induce a switch in phenotype.

Carnosic acid, an inducer of NAD(P)H quinone oxidoreductase 1, enhances the cytotoxicity of β-lapachone in melanoma cell lines

NAD(P)H quinone oxidoreductase 1 (NQO1)-dependent antitumor drugs such as β-lapachone (β-lap) are attractive candidates for cancer chemotherapy because several tumors exhibit higher expression of NQO1 than adjacent tissues. Although the association between NQO1 and β-lap has been elucidated, the effects of a NQO1-inducer and β-lap used in combination remain to be clarified. It has previously been reported that melanoma cell lines have detectable levels of NQO1 expression and are sensitive to NQO1-dependent drugs such as 17-allylamino-17-demethoxygeldanamycin. The present study was conducted to investigate the involvement of NQO1 in β-lap-mediated toxicity and the utility of combination treatment with a NQO1-inducer and β-lap in malignant melanoma cell lines. Decreased expression or inhibition of NQO1 caused these cell lines to become less sensitive to β-lap, indicating a requirement of NQO1 activity for β-lap-mediated toxicity. Of note was that carnosic acid (CA), a compound extracted from rosemary, was able to induce further expression of NQO1 through NF-E2 related factor 2 (NRF2) stabilization, thus significantly enhancing the cytotoxicity of β-lap in all of the melanoma cell lines tested. Taken together, the data presented in the current study indicated that the NRF2-NQO1 axis may have potential value as a therapeutic target in malignant melanoma to improve the rate of clinical response to NQO1-dependent antitumor drugs.

The Contribution of Oxidative Stress and Inflamm-Aging in Human and Equine Asthma

Aging is associated with a dysregulation of the immune system, leading to a general pro-inflammatory state of the organism, a process that has been named inflamm-aging. Oxidative stress has an important role in aging and in the regulation of immune responses, probably playing a role in the development of age-related diseases. The respiratory system function physiologically declines with the advancement of age. In elderly asthmatic patients, this may contribute to disease expression. In this review, we will focus on age-related changes affecting the immune system and in respiratory structure and function that could contribute to asthma occurrence, and/or clinical presentation in the elderly. Also, naturally occurring equine asthma will be discussed as a possible model for studying the importance of oxidative stress and immun-aging/inflamm-aging in humans.

Protective effects of rosmarinic acid against hydrogen peroxide‑induced cellular senescence and the inflammatory response in normal human dermal fibroblasts

Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS) that induces numerous cellular events, including cellular senescence and inflammatory responses. Therefore, the aim of this study was to investigate the protective effect of Rosmarinic acid (RA) in H2O2‑induced oxidative stress in normal human dermal fibroblasts (NHDFs). Cytotoxicity assays were performed using a water‑soluble tetrazolium salt, and senescence‑associated β‑galactosidase activity was determined to investigate the proportion of senescent cells. Antioxidant capacities were evaluated via H2O2‑scavenging activity, reverse transcription‑quantitative polymerase chain reaction, NRF2 luciferase reporter gene activity and intracellular ROS scavenging assays. Cytokine‑coded gene expression analysis and nuclear factor‑κB luciferase activity were determined to verify the anti‑inflammatory effect of RA. As a result, the present study demonstrated that rosmarinic acid inhibited H2O2‑induced oxidative stress and inflammatory responses in normal human dermal fibroblasts. Initially, the doses of RA that exerted minimal cytotoxic effects in NHDFs were determined using a cytotoxicity assay. Subsequently, pretreatment with the appropriate doses of RA significantly reversed the H2O2‑induced decrease in NHDF cell viability and decreased cellular senescence of NHDFs. In addition, RA inhibited H2O2‑induced ROS production in NHDFs, as determined by a ROS scavenging assay. The protective effects of RA were mediated by the inhibition of nuclear factor erythroid‑derived 2‑like 2, a transcription factor that functions as a key regulator of redox sensitivity. Furthermore, RA suppressed H2O2‑induced inflammation in NHDFs and significantly rescued H2O2‑induced downregulation of sirtuin 1. RA also inhibited nuclear factor (NF)‑κB transcriptional activity and the expression of NF‑κB target genes, including tumor necrosis factor‑α and interleukin‑6, in H2O2‑exposed NHDFs. Taken together, these data indicate that RA inhibits H2O2‑induced cellular damage in NHDFs.

Ferrosenescence: The iron age of neurodegeneration?

Aging has been associated with iron retention in many cell types, including the neurons, promoting neurodegeneration by ferroptosis. Excess intracellular iron accelerates aging by damaging the DNA and blocking genomic repair systems, a process we define as ferrosenescence. Novel neuroimaging and proteomic techniques have pinpointed indicators of both iron retention and ferrosenescence, allowing for their early correction, potentially bringing prevention of neurodegenerative disorders within reach. In this review, we take a closer look at the early markers of iron dyshomeostasis in neurodegenerative disorders, focusing on preventive strategies based on nutritional and microbiome manipulations.

Nitroxides as Antioxidants and Anticancer Drugs

Nitroxides are stable free radicals that contain a nitroxyl group with an unpaired electron. In this paper, we present the properties and application of nitroxides as antioxidants and anticancer drugs. The mostly used nitroxides in biology and medicine are a group of heterocyclic nitroxide derivatives of piperidine, pyrroline and pyrrolidine. The antioxidant action of nitroxides is associated with their redox cycle. Nitroxides, unlike other antioxidants, are characterized by a catalytic mechanism of action associated with a single electron oxidation and reduction reaction. In biological conditions, they mimic superoxide dismutase (SOD), modulate hemoprotein’s catalase-like activity, scavenge reactive free radicals, inhibit the Fenton and Haber-Weiss reactions and suppress the oxidation of biological materials (peptides, proteins, lipids, etc.). The use of nitroxides as antioxidants against oxidative stress induced by anticancer drugs has also been investigated. The application of nitroxides and their derivatives as anticancer drugs is discussed in the contexts of breast, hepatic, lung, ovarian, lymphatic and thyroid cancers under in vivo and in vitro experiments. In this article, we focus on new natural spin-labelled derivatives such as camptothecin, rotenone, combretastatin, podophyllotoxin and others. The applications of nitroxides in the aging process, cardiovascular disease and pathological conditions were also discussed.

Extracellular matrix alterations in senescent cells and their significance in tissue homeostasis

Normal cells after a defined number of successive divisions or after exposure to genotoxic stresses are becoming senescent, characterized by a permanent growth arrest. In addition, they secrete increased levels of pro-inflammatory and catabolic mediators, collectively termed "senescence-associated secretory phenotype". Furthermore, senescent cells exhibit an altered expression and organization of many extracellular matrix components, leading to specific remodeling of their microenvironment. In this review we present the current knowledge on extracellular matrix alterations associated with cellular senescence and critically discuss certain characteristic examples, highlighting the ambiguous role of senescent cells in the homeostasis of various tissues under both normal and pathologic conditions.

Transient postnatal overfeeding causes liver stress-induced premature senescence in adult mice

Unbalanced nutrition early in life is increasingly recognized as an important factor in the development of chronic, non-communicable diseases at adulthood, including metabolic diseases. We aimed to determine whether transient postnatal overfeeding (OF) leads to liver stress-induced premature senescence (SIPS) of hepatocytes in association with liver structure and hepatic function alterations. Litters sizes of male C57BL/6 mice were adjusted to 9 pups (normal feeding, NF) or reduced to 3 pups during the lactation period to induce transient postnatal OF. Compared to the NF group, seven-month-old adult mice transiently overfed during the postnatal period were overweight and developed glucose intolerance and insulin resistance. Their livers showed microsteatosis and fibrosis, while hepatic insulin signaling and glucose transporter protein expressions were altered. Increased hepatic oxidative stress (OS) was observed, with increased superoxide anion production, glucose-6-phosphate dehydrogenase protein expression, oxidative DNA damage and decreased levels of antioxidant defense markers, such as superoxide dismutase and catalase proteins. Hepatocyte senescence was characterized by increased p21^WAF, p53, Acp53, p16^INK4a and decreased pRb/Rb and Sirtuin-1 (SIRT-1) protein expression levels. Transient postnatal OF induces liver OS at adulthood, associated with hepatocyte SIPS and alterations in liver structure and hepatic functions, which could be mediated by a SIRT-1 deficiency.

Celastrol alleviates angiotensin II‑mediated vascular smooth muscle cell senescence via induction of autophagy

Reactive oxygen species (ROS) production has been implicated in the promotion of cellular senescence. Celastrol, a quinone methide triterpenoid isolated from the Celastraceae family, exerts antioxidant effects and enhances autophagy in various cell types. Since autophagy serves an important role in regulating ROS, it was hypothesized that the antioxidant effect of celastrol is via enhanced autophagy, thus inhibiting cell senescence. Therefore, the present study used a Senescence β‑Galactosidase Staining kit, western blot analysis and cell cycle analysis to investigate whether celastrol alleviates angiotensin (Ang) II‑induced cellular senescence by upregulating autophagy in vascular smooth muscle cells (VSMCs). The results demonstrated that celastrol reduced Ang II‑induced senescence of VSMCs. Ang II‑induced generation of ROS and the subsequent VSMC senescence were counteracted by pretreatment with celastrol, determined by a ROS assay kit. Celastrol significantly upregulated VSMC autophagy, which reduced intracellular ROS and the subsequent cellular senescence induced by Ang II. Furthermore, celastrol markedly suppressed activity of the mechanistic target of rapamycin signaling pathway in VSMCs. In conclusion, the present study demonstrated that celastrol counteracts VSMC senescence probably by reducing ROS production via activation of autophagy, which may hold promise for the prevention and treatment of aging‑associated cardiovascular disorders such as atherosclerosis.

Ginsenoside Rg3 Prevents Oxidative Stress-Induced Astrocytic Senescence and Ameliorates Senescence Paracrine Effects on Glioblastoma

Senescent astrocytes in aging brain express senescence-associated secretory phenotype (SASP) and link with increased brain aging and its related diseases. In order to determine whether ginsenosides ameliorate the astrocytic senescence in vitro, human astrocytic CRT cells and primary rat astrocytes were used in the present study. Ginsenosides Rg1, Re, Rb1 and Rg3 (5 μg/mL) could effectively prevent the astrocytic senescence induced by H₂O₂ exposure. However, these ginsenosides did not reverse the astrocytic senescence. Importantly, senescent astrocytes herein produce SASP. The expression of major components of SASP, IL-6 and IL-8, are greatly increased in senescent astrocytes. Ginsenoside Rg3 (10 μg/mL) effectively suppressed the expressions of IL-6 and IL-8, which is associated with regulations of NF-κB and p38MAPK activation. In addition, after incubation with Rg3, conditioned medium from senescent astrocytic CRT cells significantly decreased the ability to promote the proliferation of astrocytoma U373-MG, U87-MG and U251-MG cells compared with non-treated senescent samples. Similar patterns were confirmed in chemotherapy-induced glioblastoma senescent cells. The present study explored a potential candidate for amelioration of astrocytic senescence and SASP in brain aging, which provided a basis for developing strategies to reduce the dark side of senescence in normal or pathological aging process.

Molecular and biochemical evidence on the protective role of ellagic acid and silybin against oxidative stress-induced cellular aging

Aging is a natural process in living organisms that is defined by some molecular and cellular changes with time. Various causes such as mitochondrial DNA aberrations, aggregation of proteins, telomere shortening, and oxidative stress have an influential role in aging of the cells. Natural antioxidants are compounds that are potent to protect the body from detrimental effects of molecules such as free radicals. The aim of this study was to evaluate the anti-aging properties of ellagic acid (EA) and silybin (SIL), as natural antioxidant compounds on rat embryonic fibroblast (REF) cells. These cells were pre-incubated with EA and SIL, thereafter were exposed to hydrogen peroxide (H₂O₂). Then, the cell viability, SA-β-GAL activity, distribution of cell cycle, NF-κB, and mitochondrial complex I, II/IV enzyme activity were measured. The results of this study revealed the protective effects of EA and SIL in H₂O₂-treated REF cells, which confirm the previous achieved data on antioxidant and anti-inflammatory characteristics of EA and SIL against H₂O₂ in the treated REF cells. However, more new in vivo experiments are required to discover the anti-aging effects and mechanism of action of such compounds.

Aging: Molecular Pathways and Implications on the Cardiovascular System

The world's population over 60 years is growing rapidly, reaching 22% of the global population in the next decades. Despite the increase in global longevity, individual healthspan needs to follow this growth. Several diseases have their prevalence increased by age, such as cardiovascular diseases, the leading cause of morbidity and mortality worldwide. Understanding the aging biology mechanisms is fundamental to the pursuit of cardiovascular health. In this way, aging is characterized by a gradual decline in physiological functions, involving the increased number in senescent cells into the body. Several pathways lead to senescence, including oxidative stress and persistent inflammation, as well as energy failure such as mitochondrial dysfunction and deregulated autophagy, being ROS, AMPK, SIRTs, mTOR, IGF-1, and p53 key regulators of the metabolic control, connecting aging to the pathways which drive towards diseases. In addition, senescence can be induced by cellular replication, which resulted from telomere shortening. Taken together, it is possible to draw a common pathway unifying aging to cardiovascular diseases, and the central point of this process, senescence, can be the target for new therapies, which may result in the healthspan matching the lifespan.

Mitochondrial Superoxide Increases Age-Associated Susceptibility of Human Dermal Fibroblasts to Radiation and Chemotherapy

Elderly cancer patients treated with ionizing radiation (IR) or chemotherapy experience more frequent and greater normal tissue toxicity relative to younger patients. The current study demonstrates that exponentially growing fibroblasts from elderly (old) male donor subjects (70, 72, and 78 years) are significantly more sensitive to clonogenic killing mediated by platinum-based chemotherapy and IR (∼70%-80% killing) relative to young fibroblasts (5 months and 1 year; ∼10%-20% killing) and adult fibroblasts (20 years old; ∼10%-30% killing). Old fibroblasts also displayed significantly increased (2-4-fold) steady-state levels of O₂^•-, O₂ consumption, and mitochondrial membrane potential as well as significantly decreased (40%-50%) electron transport chain (ETC) complex I, II, IV, V, and aconitase (70%) activities, decreased ATP levels, and significantly altered mitochondrial structure. Following adenoviral-mediated overexpression of SOD2 activity (5-7-fold), mitochondrial ETC activity and aconitase activity were restored, demonstrating a role for mitochondrial O₂^•- in these effects. Old fibroblasts also demonstrated elevated levels of endogenous DNA damage that were increased following treatment with IR and chemotherapy. Most importantly, treatment with the small-molecule, superoxide dismutase mimetic (GC4419; 0.25 μmol/L) significantly mitigated the increased sensitivity of old fibroblasts to IR and chemotherapy and partially restored mitochondrial function without affecting IR or chemotherapy-induced cancer cell killing. These results support the hypothesis that age-associated increased O₂^•- and resulting DNA damage mediate the increased susceptibility of old fibroblasts to IR and chemotherapy that can be mitigated by GC4419. Cancer Res; 77(18); 5054-67. ©2017 AACR.

Long Noncoding RNAs and RNA-Binding Proteins in Oxidative Stress, Cellular Senescence, and Age-Related Diseases

Cellular senescence is a complex biological process that leads to irreversible cell-cycle arrest. Various extrinsic and intrinsic insults are associated with the onset of cellular senescence and frequently accompany genomic or epigenomic alterations. Cellular senescence is believed to contribute to tumor suppression, immune response, and tissue repair as well as aging and age-related diseases. Long noncoding RNAs (lncRNAs) are >200 nucleotides long, poorly conserved, and transcribed in a manner similar to that of mRNAs. They are tightly regulated during various cellular and physiological processes. Although many lncRNAs and their functional roles are still undescribed, the importance of lncRNAs in a variety of biological processes is widely recognized. RNA-binding proteins (RBPs) have a pivotal role in posttranscriptional regulation as well as in mRNA transport, storage, turnover, and translation. RBPs interact with mRNAs, other RBPs, and noncoding RNAs (ncRNAs) including lncRNAs, and they are involved in the regulation of a broad spectrum of cellular processes. Like other cell fate regulators, lncRNAs and RBPs, separately or cooperatively, are implicated in initiation and maintenance of cellular senescence, aging, and age-related diseases. Here, we review the current understanding of both lncRNAs and RBPs and their association with oxidative stress, senescence, and age-related diseases.

Role of Kallistatin Treatment in Aging and Cancer by Modulating miR-34a and miR-21 Expression

Kallistatin is an endogenous protein that regulates differential signaling pathways and a wide spectrum of biological activities via its two structural elements: an active site and a heparin-binding domain. Kallistatin via its heparin-binding site inhibits vascular inflammation and oxidative stress by antagonizing TNF-α-induced NADPH oxidase activity, NF-κB activation, and inflammatory gene expression in endothelial cells. Moreover, kallistatin via its active site inhibits microRNA-34a (miR-34a) synthesis and stimulates eNOS and SIRT1 expression in endothelial progenitor cells, whereas its heparin-binding site is crucial for blocking TNF-α-induced miR-21 expression and oxidative stress, thus reducing cellular senescence. By downregulating miR-34a and miR-21 expression, kallistatin treatment attenuates oxidative damage and aortic senescence in streptozotocin-induced diabetic mice and extends Caenorhabditis elegans lifespan under stress conditions. Likewise, kallistatin through the heparin-binding site inhibits TGF-β-induced miR-21 synthesis and oxidative stress in endothelial cells, resulting in inhibition of endothelial-mesenchymal transition, a process contributing to fibrosis and cancer. Furthermore, kallistatin's active site is essential for stimulating miR-34a and p53 expression and inhibiting the miR-21-Akt-Bcl-2 signaling pathway, thus inducing apoptosis in breast cancer cells. These findings reveal novel mechanisms of kallistatin in protection against senescence, aging, and cancer development by modulating miR-34a and miR-21 levels and inhibiting oxidative stress.

MicroRNA Regulation of Oxidative Stress-Induced Cellular Senescence

Aging is a time-related process of functional deterioration at cellular, tissue, organelle, and organismal level that ultimately brings life to end. Cellular senescence, a state of permanent cell growth arrest in response to cellular stress, is believed to be the driver of the aging process and age-related disorders. The free radical theory of aging, referred to as oxidative stress (OS) theory below, is one of the most studied aging promoting mechanisms. In addition, genetics and epigenetics also play large roles in accelerating and/or delaying the onset of aging and aging-related diseases. Among various epigenetic events, microRNAs (miRNAs) turned out to be important players in controlling OS, aging, and cellular senescence. miRNAs can generate rapid and reversible responses and, therefore, are ideal players for mediating an adaptive response against stress through their capacity to fine-tune gene expression. However, the importance of miRNAs in regulating OS in the context of aging and cellular senescence is largely unknown. The purpose of our article is to highlight recent advancements in the regulatory role of miRNAs in OS-induced cellular senescence.

Proteomics and metabolomics-driven pathway reconstruction of mung bean for nutraceutical evaluation

Mung bean is a legume crop which has a various health-promoting effects. Although rich flavonoids are reported to be responsible for its biological activities, little is known about other nutrients that may potentiate the activities. To obtain information on mung bean nutritional properties, gel-free/label-free proteomic analysis and metabolomic profiling were combined. Pathway reconstruction detected that amino acid metabolism is more active in flesh. Coat contained wider variety of lipids and phenolic acids/flavonoids than flesh. Among the compounds detected in coat, sphingolipids, arachidonic acid, and prostaglandin E2 are compounds which are related to immune response induction. Furthermore, identification of prostaglandin F2α added scientific support to empirical validity of mung bean usage. The abundance of bioactive compounds such as naringenin, which can be metabolized into vitexin, varied among cultivars. These results suggest that lipids together with flavonoids might be potential responsible compounds for biological activity of mung bean coat and flesh.