MicroRNA-339 and microRNA-556 regulate Klotho expression in vitro

Upstream and downstream regulators of Klotho expression in chronic kidney disease

Klotho is a critical protein that protects the kidney. Klotho is severely downregulated in chronic kidney disease (CKD), and its deficiency is implicated in the pathogenesis and progression of CKD. Conversely, an increase in Klotho levels results in improved kidney function and delays CKD progression, supporting the notion that modulating Klotho levels could represent a possible therapeutic strategy for CKD treatment. Nevertheless, the regulatory mechanisms responsible for the loss of Klotho remain elusive. Previous studies have demonstrated that oxidative stress, inflammation, and epigenetic modifications can modulate Klotho levels. These mechanisms result in a decrease in Klotho mRNA transcript levels and reduced translation, thus can be grouped together as upstream regulatory mechanisms. However, therapeutic strategies that aim to rescue Klotho levels by targeting these upstream mechanisms do not always result in increased Klotho, indicating the involvement of other regulatory mechanisms. Emerging evidence has shown that endoplasmic reticulum (ER) stress, the unfolded protein response, and ER-associated degradation also affect the modification, translocation, and degradation of Klotho, and thus are proposed to be downstream regulatory mechanisms. Here, we discuss the current understanding of upstream and downstream regulatory mechanisms of Klotho and examine potential therapeutic strategies to upregulate Klotho expression for CKD treatment.

Association of circulatory Klotho levels and its expression with miRNA- 339 in patients with schizophrenia

Schizophrenia is one of the major neuropsychiatric disorders affecting 1% of the population worldwide. Neuroinflammation, neurodevelopment, and oxidative stress are some of the crucial factors that can contribute to the pathogenesis of Schizophrenia. Klotho gene is an antiaging gene whose dysregulated expression can lead to Schizophrenia and aging-like symptoms in patients. Klotho gene expression is regulated by miRNA- 339, which might lead to expression changes of the klotho gene in schizophrenia patients. This study aimed to determine the Role of miRNA- 339-5p in the Regulation of Klotho Gene Expression and its Circulatory Levels in Schizophrenia. In this study total of 60 cases, schizophrenia patients and 30 healthy controls were recruited, and written informed consent was obtained from all the study subjects. The klotho gene and miRNA - 339-5p expressions were done using a reverse transcription polymerase chain reaction. And relative fold change expression was calculated by Livaak's method, that is 2^-double delta ct. It was found that the klotho gene is around 2.08 times upregulated as compared to healthy control, and miRNA- 339-5p was downregulated and showed an inverse relationship. The present study is the first to evaluate the klotho gene expression and correlate it with miRNA- 339-5p. Further confirmation of the results study should be planned with a large sample size and with drug naïve patients.

Ageing at Molecular Level: Role of MicroRNAs

The progression of age triggers a vast number of diseases including cardiovascular, cancer, and neurodegenerative disorders. Regardless of our plentiful knowledge about age-related diseases, little is understood about molecular pathways that associate the ageing process with various diseases. Several cellular events like senescence, telomere dysfunction, alterations in protein processing, and regulation of gene expression are common between ageing and associated diseases. Accumulating information on the role of microRNAs (miRNAs) suggests targeting miRNAs can aid our understanding of the interplay between ageing and associated diseases. In the present chapter, we have attempted to explore the information available on the role of miRNAs in ageing of various tissues/organs and diseases and understand the molecular mechanism of ageing.

BMSC-derived exosomes protect against kidney injury through regulating klotho in 5/6 nephrectomy rats

Aim

The aim of this study was to investigate the renoprotective effects of exosomes derived from rat bone marrow mesenchymal stem cells (rBMSCs) in a rat model of 5/6 nephrectomy (Nx)-induced chronic kidney disease (CKD).

Methods

A rat model of 5/6 Nx-induced CKD was established using conventional method. rBMSC-derived exosomes were isolated using ultracentrifugation and characterized. The exosomes were injected into 5/6 Nx rats through the caudal vein. After 12 weeks, 24 h proteinuria, serum creatinine (SCr), and blood urea nitrogen (BUN) levels were evaluated, and renal pathology was analyzed by H&E and Masson staining, and transmission electron microscopy. The expression of klotho was analyzed and the activity of the klotho promoter was evaluated using a luciferase reporter assay.

Results

The isolated exosomes showed typical morphological features. Exosomes transplantation reduced 24 h urinary protein excretion, and SCr and BUN levels in 5/6 Nx-induced CKD rats. Furthermore, renal pathology was improved in the exosome-treated 5/6 Nx rats. Mechanistically, the exosomes significantly upregulated the activity of klotho promoter and its expression.

Conclusions

Transplantation of rBMSC-derived exosomes may protect against kidney injury, probably by regulating klotho activity and expression. Our results provide a theoretical basis for the application of rBMSC-derived exosomes in CKD therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00742-8.

Investigation of the Role of Induced Overexpression of the Isolated Secreted Klotho on the A-172 Human Glioblastoma Cells

Klotho gene, identified in 1997 as an anti-aging gene, can manufacture two protein products: transmembrane and secreted forms. The later research revealed the involvement of klotho in carcinogenesis. However, little is known about the action of different Klotho forms on antitumor effects is still. The purpose of this article is to evaluate the effect of isolated secreted Klotho overexpression on the growth features of human glioblastoma cell line A-172.A-172 was transfected by a plasmid vector incorporating secreted Klotho sequence by the liposomal method. Overexpression assay was carried out quantitatively on both mRNA and protein using RT-qPCR and ELISA, correspondingly. It was shown that the relative expression of secreted Klotho in the experimental group was significantly higher than in the untransfected group by both methods (p < 0.001). At the same time, the growth curves and MTT proliferation assay demonstrated significantly decreased values under induced overexpression (p < 0.01). The increased amount of cells with activated caspases and annexin V (p < 0.001) corresponded with the expression of secreted Klotho. This mechanism, as suggested, maybe causative of the observed effects.

Klotho and Mesenchymal Stem Cells: A Review on Cell and Gene Therapy for Chronic Kidney Disease and Acute Kidney Disease

Chronic kidney disease (CKD) and acute kidney injury (AKI) are public health problems, and their prevalence rates have increased with the aging of the population. They are associated with the presence of comorbidities, in particular diabetes mellitus and hypertension, resulting in a high financial burden for the health system. Studies have indicated Klotho as a promising therapeutic approach for these conditions. Klotho reduces inflammation, oxidative stress and fibrosis and counter-regulates the renin-angiotensin-aldosterone system. In CKD and AKI, Klotho expression is downregulated from early stages and correlates with disease progression. Therefore, the restoration of its levels, through exogenous or endogenous pathways, has renoprotective effects. An important strategy for administering Klotho is through mesenchymal stem cells (MSCs). In summary, this review comprises in vitro and in vivo studies on the therapeutic potential of Klotho for the treatment of CKD and AKI through the administration of MSCs.

Epigenetic modifications of Klotho expression in kidney diseases

Developments of many renal diseases are substantially influenced by epigenetic modifications of numerous genes, mainly mediated by DNA methylations, histone modifications, and microRNA interference; however, not all gene modifications causally affect the disease onset or progression. Klotho is a critical gene whose repressions in various pathological conditions reportedly involve epigenetic regulatory mechanisms. Klotho is almost unexceptionally repressed early after acute or chronic renal injuries and its levels inversely correlated with the disease progression and severity. Moreover, the strategies of Klotho derepression via epigenetic modulations beneficially change the pathological courses both in vitro and in vivo. Hence, Klotho is not only considered a biomarker of the renal disease but also a potential or even an ideal target of therapeutic epigenetic intervention. Here, we summarize and discuss studies that investigate the Klotho repression and intervention in renal diseases from an epigenetic point of view. These information might shed new sights into the effective therapeutic strategies to prevent and treat various renal disorders.

Epigenetic and non-epigenetic regulation of Klotho in kidney disease

Klotho is a novel renoprotective anti-aging protein available in membrane-bound or soluble form. Klotho is expressed in brain, pancreas, and other solid organs but shows highest expression levels in the kidney. Klotho sustains normal kidney physiology but Klotho regulation also contributes to the progression of kidney disease. Systemic and intrarenal levels of Klotho fall drastically during acute kidney injury, kidney fibrosis, diabetic nephropathy, and other forms of chronic kidney disease, etc. Moreover, exogenous supplementation or overexpression of endogenous Klotho attenuates kidney disease. The regulation of endogenous Klotho expression involves epigenetic as well as non-epigenetic mechanisms. The epigenetic modifications such as DNA methylation, post-translational histone modifications, miRNAs regulate the change in Klotho expression in kidney disease. Non-epigenetic mechanisms such as ER stress, Wnt signaling, activation of the renin angiotensin system (RAS), excessive reactive oxygen species and cytokine generation, albumin overload, and PPAR-γ signaling also contribute to Klotho regulation. Evolving evidence highlight the capacity of natural products to regulate Klotho expression in kidney disease. All these preclinical data suggest that Klotho could be a novel biomarker as well as therapeutic target. Here we review the different mechanisms of Klotho regulation in the context of Klotho as a biomarker and potential therapeutic agent.

Sweet Control: MicroRNA Regulation of the Glycome

Glycosylation is a sophisticated informational system that controls specific biological functions at the cellular and organismal level. Dysregulation of glycosylation may underlie some of the most complex and common diseases of the modern era. In the past 5 years, microRNAs have come to the forefront as a critical regulator of the glycome. Herein, we review the current literature on miRNA regulation of glycosylation and how this work may point to a new way to identify the biological importance of glycosylation enzymes.

Thrombin, a Mediator of Coagulation, Inflammation, and Neurotoxicity at the Neurovascular Interface: Implications for Alzheimer's Disease

The societal burden of Alzheimer’s disease (AD) is staggering, with current estimates suggesting that 50 million people world-wide have AD. Identification of new therapeutic targets is a critical barrier to the development of disease-modifying therapies. A large body of data implicates vascular pathology and cardiovascular risk factors in the development of AD, indicating that there are likely shared pathological mediators. Inflammation plays a role in both cardiovascular disease and AD, and recent evidence has implicated elements of the coagulation system in the regulation of inflammation. In particular, the multifunctional serine protease thrombin has been found to act as a mediator of vascular dysfunction and inflammation in both the periphery and the central nervous system. In the periphery, thrombin contributes to the development of cardiovascular disease, including atherosclerosis and diabetes, by inducing endothelial dysfunction and related inflammation. In the brain, thrombin has been found to act on endothelial cells of the blood brain barrier, microglia, astrocytes, and neurons in a manner that promotes vascular dysfunction, inflammation, and neurodegeneration. Thrombin is elevated in the AD brain, and thrombin signaling has been linked to both tau and amyloid beta, pathological hallmarks of the disease. In AD mouse models, inhibiting thrombin preserves cognition and endothelial function and reduces neuroinflammation. Evidence linking atrial fibrillation with AD and dementia indicates that anticoagulant therapy may reduce the risk of dementia, with targeting thrombin shown to be particularly effective. It is time for “outside-the-box” thinking about how vascular risk factors, such as atherosclerosis and diabetes, as well as the coagulation and inflammatory pathways interact to promote increased AD risk. In this review, we present evidence that thrombin is a convergence point for AD risk factors and as such that thrombin-based therapeutics could target multiple points of AD pathology, including neurodegeneration, vascular activation, and neuroinflammation. The urgent need for disease-modifying drugs in AD demands new thinking about disease pathogenesis and an exploration of novel drug targets, we propose that thrombin inhibition is an innovative tactic in the therapeutic battle against this devastating disease.

Epigenetic changes during ageing and their underlying mechanisms

As life expectancy increases worldwide, ageing and age-related diseases arise as a major issue for societies around the globe. Understanding the biological mechanisms underlying the ageing process is thus instrumental for the development of efficient interventions aimed to prevent and treat age-related conditions. Current knowledge in the biogerontology field points to epigenetics as a critical component of the ageing process, not only by serving as a bona-fide marker of biological age but also by controlling and conferring inheritability to cellular and organismal ageing. This is reflected by a myriad of evidences demonstrating the relationship between DNA methylation, histone modifications, chromatin remodeling and small non-coding RNAs and several age-related phenotypes. Given the reversibility of epigenetic alterations, epigenetic reprogramming may also be envisioned as a potential approach to treat age-related disorders. Here we review how different types of epigenetic mechanisms are involved in the ageing process. In addition, we highlight how interventions modulate epigenetics and thus promote health- and lifespan.

Role of Klotho Protein in Tumor Genesis, Cancer Progression, and Prognosis in Patients with High-Grade Glioma

BACKGROUND

Klotho, a single-pass transmembrane protein associated with premature aging, acts as a tumor suppressor gene by inhibiting insulin/insulin-like growth factor-1 and fibroblast growth factor pathways. Downregulated Klotho expression is reported in melanoma, mesothelioma, bladder, breast, gastric, cervix, lung, and kidney cancers and is associated with a poor prognosis. Klotho expression and Klotho promoter hypermethylation are predictive factors for patient prognosis.

METHODS

To investigate the potential role of Klotho in glioblastoma-multiforme (GBM), 22 GBM samples were collected from the Sheba Tumor Bank and examined.

RESULTS

We found that increased Klotho messenger ribonucleic acid (RNA) expression predicted longer survival (P = 0.03) of GBM patients. Methylation analysis was performed on bisulfite-treated deoxyribonucleic acid from the GBM patient samples using ionization time-of-flight mass spectrometry according to the Sequenom EpiTYPER protocols. Klotho promoter hypermethylation was detected in 65% of the GBM samples and correlated significantly with improved survival (P < 0.04). We found 3 major Klotho promotor hypermethylation sites located 585-579 bp, 540-533 bp, and 537-534 bp upstream of the transcription start site. Methylated deoxyribonucleic acid immunoprecipitation studies confirmed these results. Notably, the messenger RNA expression in these GBM samples revealed an unexpected linear correlation with methylation of these 3 hypermethylation sites identified in the Klotho promotor. Thus Klotho expression and methylation could predict prognosis in patients with GBM.

CONCLUSIONS

Epigenetic regulation in GBM appears to be complicated. Specific CpG islands affect genes or micro RNAs that interact to control Klotho expression. The diverse effects of these islands may be due to unique factors of GBM.

microRNA-200c regulates KLOTHO expression in human kidney cells under oxidative stress

KLOTHO deficiency is associated with the progression of kidney dysfunction, whereas its overexpression exerts renoprotective effects. Oxidative stress suppresses KLOTHO expression in renal epithelial cells but upregulates microRNA-200c (miR-200c) in human umbilical vein endothelial cells. In this study, we investigated whether oxidative stress-induced miR-200c is implicated in KLOTHO downregulation in human renal tubular epithelium (HK-2) cells. HK-2 cells were stimulated with hydrogen peroxide (H₂O₂) to examine the effect of oxidative stress. A luciferase reporter containing the KLOTHO 3′-UTR was used to investigate the effect of miR-200c on KLOTHO mRNA metabolism. The expressions of KLOTHO, oxidative stress markers, and miR-200c were determined in human kidney biopsy specimens. H₂O₂ suppressed KLOTHO expression without a reduction in KLOTHO mRNA levels but upregulated miR-200c expression. Similarly, transfection of a miR-200c mimic reduced KLOTHO levels and luciferase activity without a reduction in KLOTHO mRNA levels. In contrast, transfection of a miR-200c inhibitor maintained KLOTHO expression. Immunofluorescent assay revealed KLOTHO was present in the cytosol and nuclei of HK-2 cells. In human kidney biopsies, KLOTHO expression was inversely correlated with levels of oxidative stress markers (8-hydroxy-2′-deoxyguanosine: ρ = −0.38, P = 0.026; 4-hydroxy-2-hexenal: ρ = −0.35, P = 0.038) and miR-200c (ρ = −0.34, P = 0.043). Oxidative stress-induced miR-200c binds to the KLOTHO mRNA 3′-UTR, resulting in reduced KLOTHO expression.

Human alternative Klotho mRNA is a nonsense-mediated mRNA decay target inefficiently spliced in renal disease

Klotho is a renal protein involved in phosphate homeostasis, which is downregulated in renal disease. It has long been considered an antiaging factor. Two Klotho gene transcripts are thought to encode membrane-bound and secreted Klotho. Indeed, soluble Klotho is detectable in bodily fluids, but the relative contributions of Klotho secretion and of membrane-bound Klotho shedding are unknown. Recent advances in RNA surveillance reveal that premature termination codons, as present in alternative Klotho mRNA (for secreted Klotho), prime mRNAs for degradation by nonsense-mediated mRNA decay (NMD). Disruption of NMD led to accumulation of alternative Klotho mRNA, indicative of normally continuous degradation. RNA IP for NMD core factor UPF1 resulted in enrichment for alternative Klotho mRNA, which was also not associated with polysomes, indicating no active protein translation. Alternative Klotho mRNA transcripts colocalized with some P bodies, where NMD transcripts are degraded. Moreover, we could not detect secreted Klotho in vitro. These results suggest that soluble Klotho is likely cleaved membrane-bound Klotho only. Furthermore, we found that, especially in acute kidney injury, splicing of the 2 mRNA transcripts is dysregulated, which was recapitulated by various noxious stimuli in vitro. This likely constitutes a novel mechanism resulting in the downregulation of membrane-bound Klotho.

Abnormality of Klotho Signaling Is Involved in Polycystic Ovary Syndrome

This study investigated the involvement of the klotho-associated signaling in the apoptosis of granulosa cells (GCs) from the ovaries of patients with polycystic ovary syndrome (PCOS) and PCOS animals. Primary GCs were obtained from 26 healthy women and 43 women with PCOS. The PCOS animal model was established by the injection of dehydroepiandrosterone (DHEA). Klotho protein and associated microRNA expression in human primary GCs and rats' ovarian tissues were measured by Western blot and real-time polymerase chain reaction, respectively. Results showed that significantly lower miR-126-5p and miR-29a-5p microRNA expressions, higher klotho protein expression, lower insulin growth factor 1 (IGF-1R) and Wnt family member 1 (Wnt1) protein expressions, and lower Akt phosphorylation at Ser⁴⁷³ and Thr³⁰⁸ residues were observed in the GCs from patients with PCOS and the ovarian tissues of PCOS rats compared to that in GCs from healthy women and ovarian tissues of normal control rats, respectively. Knockdown of klotho gene expression normalized IGF-1R and Wnt1 protein expressions and Akt phosphorylation in GCs from patients with PCOS and the ovarian tissues from PCOS rats; it also blocked the effects of insulin on apoptosis and proliferation in GCs from patients with PCOS and inhibited caspase-3 activity in ovarian tissues of PCOS rats. Knockdown of klotho gene expression increased the pregnancy rate in DHEA-treated female rats and increased the body weight of their newborns through normalizing the ovarian function and decreasing the formation of cystic follicles. In conclusion, the miR-126-5p, miR-29a-5p/klotho/insulin-IGF-1, Wnt, and Akt signal pathway may be involved in the apoptosis of GCs and subsequent development of PCOS.

Klotho/FGF23 Axis in Chronic Kidney Disease and Cardiovascular Disease

BACKGROUND

Membrane αKlotho (hereinafter called Klotho) is highly expressed in the kidney and functions as a coreceptor of FGF receptors (FGFRs) to activate specific fibroblast growth factor 23 (FGF23) signal pathway. FGF23 is produced in bones and participates in the maintenance of mineral homeostasis. The extracellular domain of transmembrane Klotho can be cleaved by secretases and released into the circulation as soluble Klotho. Soluble Klotho does not only weakly activate FGFRs to transduce the FGF23 signaling pathway, but also functions as an enzyme and hormonal substance to play a variety of biological functions. FGF23 exerts its biological effects through activation of FGFRs in a Klotho-dependent manner. However, extremely high FGF23 can exert its pathological action in a Klotho-independent manner.

SUMMARY

The decline in serum and urinary Klotho followed by a rise in serum FGF23 at an early stage of chronic kidney disease (CKD) functions as an early biomarker for kidney dysfunction and can also serve as a predictor for risk of cardiovascular disease (CVD) and mortality in both CKD patients and the general population. Moreover, Klotho deficiency is a pathogenic factor for CKD progression and CVD. FGF23 may also contribute to CVD. Prevention of Klotho decline, reactivation of endogenous Klotho production, or supplementation of exogenous Klotho attenuate renal fibrosis, retard CKD progression, improve mineral metabolism, ameliorate cardiomyopathy, and alleviate vascular calcification in CKD. However, the poor CVD outcome after depletion of FGF23 with FGF23 antibody stimulates the generation of a more specific inhibitor of FGF23 for CKD treatment.

KEY MESSAGE

Klotho/FGF23 may not only be diagnostic and/or prognostic biomarkers for CKD and CVD, but are also pathogenic contributors to CKD progression and CVD development. The Klotho/FGF23 axis should be a novel target for renal clinics.

Discovery of Klotho peptide antagonists against Wnt3 and Wnt3a target proteins using combination of protein engineering, protein-protein docking, peptide docking and molecular dynamics simulations

The Klotho is known as lifespan enhancing protein involved in antagonizing the effect of Wnt proteins. Wnt proteins are stem cell regulators, and uninterrupted exposure of Wnt proteins to the cell can cause stem and progenitor cell senescence, which may lead to aging. Keeping in mind the importance of Klotho in Wnt signaling, in silico approaches have been applied to study the important interactions between Klotho and Wnt3 and Wnt3a (wingless-type mouse mammary tumor virus (MMTV) integration site family members 3 and 3a). The main aim of the study is to identify important residues of the Klotho that help in designing peptides which can act as Wnt antagonists. For this aim, a protein engineering study is performed for Klotho, Wnt3 and Wnt3a. During the theoretical analysis of homology models, unexpected role of number of disulfide bonds and secondary structure elements has been witnessed in case of Wnt3 and Wnt3a proteins. Different in silico experiments were carried out to observe the effect of correct number of disulfide bonds on 3D protein models. For this aim, total of 10 molecular dynamics (MD) simulations were carried out for each system. Based on the protein–protein docking simulations of selected protein models of Klotho with Wnt3 and Wnt3a, different peptides derived from Klotho have been designed. Wnt3 and Wnt3a proteins have three important domains: Index finger, N-terminal domain and a patch of ∼10 residues on the solvent exposed surface of palm domain. Protein–peptide docking of designed peptides of Klotho against three important domains of palmitoylated Wnt3 and Wnt3a yields encouraging results and leads better understanding of the Wnt protein inhibition by proposed Klotho peptides. Further in vitro studies can be carried out to verify effects of novel designed peptides as Wnt antagonists.

Downregulation of kidney protective factors by inflammation: role of transcription factors and epigenetic mechanisms

Chronic kidney disease (CKD) is associated to an increased risk of death, CKD progression, and acute kidney injury (AKI) even from early stages, when glomerular filtration rate (GFR) is preserved. The link between early CKD and these risks is unclear, since there is no accumulation of uremic toxins. However, pathological albuminuria and kidney inflammation are frequent features of early CKD, and the production of kidney protective factors may be decreased. Indeed, Klotho expression is already decreased in CKD category G1 (normal GFR). Klotho has anti-aging and nephroprotective properties, and decreased Klotho levels may contribute to increase the risk of death, CKD progression, and AKI. In this review, we discuss the downregulation by mediators of inflammation of molecules with systemic and/or renal local protective functions, exemplified by Klotho and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a transcription factor that promotes mitochondrial biogenesis. Cytokines such as TWEAK, TNF-α, or transforming growth factor -β1 produced locally during kidney injury or released from inflammatory sites at other organs may decrease kidney expression of Klotho and PGC-1α or lead to suboptimal recruitment of these nephroprotective proteins. Transcription factors (e.g., Smad3 and NF-κB) and epigenetic mechanisms (e.g., histone acetylation or methylation) contribute to downregulate the expression of Klotho and/or PGC-1α, while histone crotonylation promotes PGC-1α expression. NF-κBiz facilitates the repressive effect of NF-κB on Klotho expression. A detailed understanding of these mediators may contribute to the development of novel therapeutic approaches to prevent CKD progression and its negative impact on mortality and AKI.

Has gene duplication impacted the evolution of Eutherian longevity?

One of the greatest unresolved questions in aging biology is determining the genetic basis of interspecies longevity variation. Gene duplication is often the key to understanding the origin and evolution of important Eutherian phenotypes. We systematically identified longevity-associated genes in model organisms that duplicated throughout Eutherian evolution. Longevity-associated gene families have a marginally significantly higher rate of duplication compared to non-longevity-associated gene families. Anti-longevity-associated gene families have significantly increased rate of duplication compared to pro-longevity gene families and are enriched in neurodegenerative disease categories. Conversely, duplicated pro-longevity-associated gene families are enriched in cell cycle genes. There is a cluster of longevity-associated gene families that expanded solely in long-lived species that is significantly enriched in pathways relating to 3-UTR-mediated translational regulation, metabolism of proteins and gene expression, pathways that have the potential to affect longevity. The identification of a gene cluster that duplicated solely in long-lived species involved in such fundamental processes provides a promising avenue for further exploration of Eutherian longevity evolution.

Epigenetic targets in cancer and aging: dietary and therapeutic interventions

INTRODUCTION

Epigenetic regulation plays a critical role in normal growth and embryonic development by controlling the transcriptional activities of several genes. A growing number of epigenetic changes have been reported in the regulation of key genes involved in cancer and aging. Drugs with epigenetic modulatory activities, mainly histone deacetylase and DNA methyltransferase inhibitors, have received wider attention in aging and cancer research.

AREAS COVERED

In this review, we summarize the major epigenetic alterations in cancer and aging, with special emphasis on possible therapeutic targets and interventions by dietary as well as bioactive phytochemicals.

EXPERT OPINION

Some epigenetic-targeting drugs have received FDA approval and many others are undergoing different phases of clinical trials for cancer therapy. In addition to the synthetic compounds, several bioactive phytochemicals and dietary interventions, such as caloric restriction, have been shown to possess epigenetic modulatory activities in multiple cancers. These epigenetic modulators have been shown to delay aging and minimize the risk of cancer both in preclinical as well as clinical models. Therefore, knowledge of bioactive phytochemicals along with dietary interventions can be utilized for cancer prevention and therapy both alone and with existing drugs to achieve optimum efficacy.

Genetics and epigenetics of aging and longevity

Evolutionary theories of aging predict the existence of certain genes that provide selective advantage early in life with adverse effect on lifespan later in life (antagonistic pleiotropy theory) or longevity insurance genes (disposable soma theory). Indeed, the study of human and animal genetics is gradually identifying new genes that increase lifespan when overexpressed or mutated: gerontogenes. Furthermore, genetic and epigenetic mechanisms are being identified that have a positive effect on longevity. The gerontogenes are classified as lifespan regulators, mediators, effectors, housekeeping genes, genes involved in mitochondrial function, and genes regulating cellular senescence and apoptosis. In this review we demonstrate that the majority of the genes as well as genetic and epigenetic mechanisms that are involved in regulation of longevity are highly interconnected and related to stress response.