Anti-aging Molecule Research Articles

Senescence is involved in the pathogenesis of chronic obstructive pulmonary disease through effects on telomeres and the anti-aging molecule fibroblast growth factor 23.

Fibroblast growth factor 23 knockout mice develop premature aging and emphysema, indicating that dysregulation of the normal aging process is involved in the pathobiology of chronic obstructive pulmonary disease. Thus, we explored the association among a coding single-nucleotide polymorphism of fibroblast growth factor 23, its protein concentration in serum and telomere length in patients with chronic obstructive pulmonary disease. The study involved 361 smokers; among whom, 244 were patients with chronic obstructive pulmonary disease. We genotyped a coding single-nucleotide polymorphism of fibroblast growth factor 23, rs7955866, and measured the telomere length of the peripheral blood cells. We also determined emphysema severity and airflow obstruction using computed tomography and pulmonary function tests, respectively. Furthermore, we analyzed the association between the disease phenotypes and fibroblast growth factor 23 genotypes or telomere length of peripheral blood leukocytes, as well as the association between the serum level of the studied protein and its genotypes. The mice with A alleles on rs7955866 showed severe upper lung emphysema (P = 0.008). The serum concentration of the tested protein was lower in the mice with A allele than in the G homozygotes (P = 0.004). Telomere shortening was associated with airflow obstruction (P = 0.009), but not with upper lung emphysema. A variation of fibroblast growth factor 23 with a reduced serum concentration appeared to promote emphysema formation. Telomere shortening in peripheral blood leukocytes was not associated with emphysema, but with airflow obstruction in chronic obstructive pulmonary disease through an independent mechanism.

STOP accelerating lung aging for the treatment of COPD

Life expectancy is assumed to rise continuously and consequently global burden of age-associated diseases is expected to increase. All vital organs begin to lose some function during aging with different rates, and the same happens on the lung. Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the lungs, which progresses very slowly and the majority of patients are therefore elderly. COPD is a major and increasing global health problem with enormous amount of expenditure of indirect/direct health care costs, and therefore, there is urgent need to clarify the molecular mechanism of COPD and develop novel treatments. We here hypothesize that environmental gases, such as cigarette smoke and kitchen pollutants, may accelerate the aging of lung or worsen aging-related events in the lung, leading to defective resolution of inflammation, reduced anti-oxidant capacity and defective disposal of abnormal proteins, and this consequently induces progression of COPD. Recent studies identified some anti-aging small molecules (geroprotectors) that may open up new avenues for the treatment of COPD.

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and kidney disease

The tumor necrosis factor-like weak inducer of apoptosis (TWEAK) cytokine has been linked to kidney injury by functional studies in experimental animals, and has biomarker potential in kidney disease. TWEAK was known to promote tubular cell injury and kidney inflammation. Recent studies have expanded these observations, identifying additional targets of TWEAK relevant to kidney injury. Thus, TWEAK upregulates the chemokine and cholesterol scavenger receptor CXCL16 and downregulates the antiaging and antifibrotic molecule Klotho in tubular cells. Furthermore, fibrogenic TWEAK actions on renal fibroblasts were described. TWEAK or factor-inducible molecule 14 targeting decreased the kidney fibrosis resulting from immune and nonimmune kidney injury induced by transient tubular or glomerular insults or by persistent urinary tract obstruction. TWEAK might also contribute to the link between chronic kidney disease and kidney cancer, as suggested by its role in other genitourinary cancers. Progress has also been made in TWEAK targeting. A phase I clinical trial showed that TWEAK targeting is well tolerated in humans, and an ongoing trial is exploring efficacy in lupus nephritis. Nanomolecules and inhibitors of epidermal growth factor receptor pathway may also protect from the adverse effects of TWEAK in the kidney. These findings suggest that TWEAK targeting has clinical potential in kidney injury of immune and nonimmune origin.

Melatonin and female reproduction

Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by the pineal gland. After entering the circulation, melatonin acts as an endocrine factor and a chemical messenger of light and darkness. It regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It also affects the brain, immune, gastrointestinal, cardiovascular, renal, bone and endocrine functions and acts as an oncostatic and anti-aging molecule. Many of melatonin's actions are mediated through interactions with specific membrane-bound receptors expressed not only in the central nervous system, but also in peripheral tissues. Melatonin also acts through non-receptor-mediated mechanisms, for example serving as a scavenger for reactive oxygen species and reactive nitrogen species. At both physiological and pharmacological concentrations, melatonin attenuates and counteracts oxidative stress and regulates cellular metabolism. Growing scientific evidence of reproductive physiology supports the role of melatonin in human reproduction. This review was conducted to investigate the effects of melatonin on female reproduction and to summarize our findings in this field.

Resveratrol in mammals: effects on aging biomarkers, age‐related diseases, and life span

Through its antioxidant, anticarcinogenic, and anti-inflammatory properties, resveratrol has become a candidate for drug development in the context of aging studies. Scientific evidence has highlighted its potential as a therapeutic agent for cardiovascular diseases and some cancers but also as an antiaging molecule. Resveratrol is thought to mimic the beneficial effects of chronic and moderate calorie restriction. Nevertheless, no study has demonstrated the prolongation of life span in healthy nonobese mammal models. This review summarizes recent findings on the effects of resveratrol on aging and life span in mammals. In our opinion, more studies should be performed to assess the effects of a chronic dietary intake of resveratrol in long-lived species close to humans, such as nonhuman primates. This will certainly generate more evidence about the ability of resveratrol to achieve the physiological benefits that have been observed in small mammal laboratory models and feature the eventual unwanted secondary effects that may occur under high levels of resveratrol.

Anti-aging molecule, Sirt1: a novel therapeutic target for diabetic nephropathy

Caloric restriction prolongs the lifespan of many species. Therefore, investigators have researched the usefulness of caloric restriction for healthy lifespan extension. Sirt1, an NAD(+)-dependent deacetylase, was identified as a molecule necessary for caloric restriction-related anti-aging strategies. Sirt1 functions as an intracellular energy sensor to detect the concentration of NAD(+), and controls in vivo metabolic changes under caloric restriction and starvation through its deacetylase activity to many targets including histones, nuclear transcriptional factors, and enzymes. During the past decade, investigators have reported the relationship between disturbance of Sirt1 activation and the onset of aging- and obesity-associated diseases such as diabetes, cardiovascular disease and neurodegenerative disorders. Consequently, a calorie restriction-mimetic action of Sirt1 is now expected as a new therapy for these diseases. In addition, recent studies have gradually clarified the role of Sirt1 in the onset of kidney disease. Its activation may also become a new target of treatment in the patients with chronic kidney disease including diabetic nephropathy. In this article, we would like to review the role of Sirt1 in the onset of kidney disease based on previous studies, and discuss its possibility as the target of treatment in diabetic nephropathy.

Can We Delay the Accelerated Lung Aging in COPD? Anti-Aging Molecules and Interventions

Chronic obstructive pulmonary disease (COPD) has been recently characterized as a disease of accelerated lung aging. The prevalence of COPD is age-dependent suggesting an intimate relationship between the pathogenesis of COPD and aging. Lung function decline, the hallmark feature of COPD evolution, is more prominent with increasing age and this decline is greater in smoking individuals. One of the major goals of COPD pharmacotherapy is the development of drugs that would be able to result in a decrease of the decline in lung function over years. However, till nowadays smoking cessation is the only known intervention which is able to decelerate lung function decline. Several mechanisms of aging, including oxidative stress, inflammation and telomere shortening have been shown to be implicated in COPD. Furthermore, numerous anti-aging molecules, including sirtuins and Nrf-2 are reduced, and pathways such as mTOR and genes such as Klotho have also been shown to be abnormal in the lungs of COPD patients. The above mechanisms have been associated with the accelerated lung aging in COPD patients. Numerous therapeutic interventions have been studied in an attempt to reverse accelerated lung aging, and some of them have already been tested in clinical trials. The aim of the present review is to summarize the mechanisms associated with the accelerated lung aging in COPD and to provide information about the possible therapeutic implications targeting those mechanisms.

Sirtuins and renal diseases: relationship with aging and diabetic nephropathy

Sirtuins are members of the Sir2 (silent information regulator 2) family, a group of class III deacetylases. Mammals have seven different sirtuins, SIRT1–SIRT7. Among them, SIRT1, SIRT3 and SIRT6 are induced by calorie restriction conditions and are considered anti-aging molecules. SIRT1 has been the most extensively studied. SIRT1 deacetylates target proteins using the coenzyme NAD+ and is therefore linked to cellular energy metabolism and the redox state through multiple signalling and survival pathways. SIRT1 deficiency under various stress conditions, such as metabolic or oxidative stress or hypoxia, is implicated in the pathophysiologies of age-related diseases including diabetes, cardiovascular diseases, neurodegenerative disorders and renal diseases. In the kidneys, SIRT1 may inhibit renal cell apoptosis, inflammation and fibrosis, and may regulate lipid metabolism, autophagy, blood pressure and sodium balance. Therefore the activation of SIRT1 in the kidney may be a new therapeutic target to increase resistance to many causal factors in the development of renal diseases, including diabetic nephropathy. In addition, SIRT3 and SIRT6 are implicated in age-related disorders or longevity. In the present review, we discuss the protective functions of sirtuins and the association of sirtuins with the pathophysiology of renal diseases, including diabetic nephropathy.

Chronic kidney disease and vascular remodelling: molecular mechanisms and clinical implications

CKD (chronic kidney disease) is a severe and complex disease with a very high prevalence of CV (cardiovascular) complications. CKD patients are exposed to haemodynamic disturbances in addition to severe metabolic abnormalities that lead to a specific form of arterial remodelling, which contributes to the development of CV disease. Arterial calcification is a major event in the arterial remodelling process and is strongly linked to mineral metabolism abnormalities associated with CKD. Arterial remodelling is not limited to arterial calcification and modifications in arterial wall composition are also observed. Activation of the RAS (renin-angiotensin system), ET-1 (endothelin-1), endothelial dysfunction, oxidative stress and ADMA (asymmetric ω-NG,NG-dimethylarginine), as well as the anti-aging molecule Klotho, are implicated in this process. The present review details the mechanisms involved in arterial calcification and arterial remodelling associated with CKD, and provides the clinical consequences of large and small artery stiffness and remodelling in CKD patients.

Geroprotectors as a novel therapeutic strategy for COPD, an accelerating aging disease

Chronic obstructive pulmonary disease (COPD) progresses very slowly and the majority of patients are therefore elderly. COPD is characterized by an abnormal persistent inflammatory response to noxious environmental stimuli and there are increasing evidences for a close relationship between premature aging and chronic inflammatory diseases. Thus, COPD is considered to be a disease of an accelerating aging. In this review, we collected the evidence for roles of aging on pathogenesis of COPD and considered future therapeutic strategy for COPD based on this senescence hypothesis. Since calorie restriction has been proved to extend lifespan, many efforts were made to clarify the molecular mechanism of aging. Aging is defined as the progressive decline of homeostasis that occurs after the reproductive phase of life is complete, leading to an increasing risk of disease or death due to impaired DNA repair after damage by oxidative stress or telomere shortening as a result of repeated cell division. During aging, pulmonary function progressively deteriorates; innate immunity is impaired and pulmonary inflammation increases, accompanied by structural changes, such as an enlargement of airspaces. Noxious environmental gases, such as cigarette smoke, may worsen these aging-related events in the lung or accelerate aging of the lung due to reduction in anti-aging molecules and/or stimulation of aging molecules. Aging signaling are complex but conserved in divert species, such as worm, fruit fry, rodent and humans. Especially the insulin like growth factor (IGF-1) signaling was well documented. Geroprotectors are therapeutics that affect the root cause of aging and age-related diseases, and thus prolong the life-span of animals. Most of geroprotectors such as melatonin, metformin, rapamycin and resveratrol are anti-oxidant or anti-aging molecule regulators. Therefore, geroprotection for the lung might be an attractive approach for the treatment of COPD by preventing premature aging of lung.

SIRT3 attenuates palmitate-induced ROS production and inflammation in proximal tubular cells

Free fatty acid (FFA)-mediated renal lipotoxicity is associated with the progression of tubulointerstitial inflammation in proteinuric kidney disease. SIRT3 is an antiaging molecule regulated by calorie restriction and mitochondria-localized NAD +-dependent deacetylase. In this study, we investigated whether SIRT3 reversed renal lipotoxicity-mediated ROS and inflammation. In the kidney of the FFA-bound BSA-overloaded mouse, which is a well-established experimental model of FFA-associated tubulointerstitial inflammation, mRNA expression of SIRT3 was significantly decreased and negatively correlated with mRNA expression of an inflammatory cytokine, monocyte chemoattractant protein-1 (MCP-1). In cultured proximal tubular (mProx) cells, the saturated FFA palmitate stimulated ROS accumulation and expression of MCP-1. These effects were ameliorated by retrovirus-mediated overexpression of SIRT3, whereas they were exacerbated by either overexpression of a dominant-negative form of SIRT3(N87A) lacking deacetylase activity or knockdown of SIRT3 by siRNA transfection. Furthermore, we showed that SIRT3 positively regulated both mitochondrial oxidative capacity and antioxidant gene expression, thereby reducing ROS accumulation in mProx cells, which suggests a mechanism that underlies SIRT3-mediated reversal of palmitate-induced inflammation. In conclusion, these results highlight a new role for SIRT3 in lipotoxicity/ROS-related inflammation, reveal a new molecular mechanism underlying calorie restriction-mediated antioxidant and anti-inflammatory effects, and could aid in the design of new therapies for the prevention of tubulointerstitial lesions in proteinuric kidney disease.

Strategies for the discovery of anti-aging compounds

Importance of the field: Life expectancy has increased across the globe and the number of aged people is increasing rapidly. With the rise in the average age of people, the prevalence of age related pathologies has also increased and thus the strategies to find anti-aging molecules assume significance. Anti-aging basically concerns the prevention or delaying the alterations taking place as a function of age which are manifested as age-associated illnesses.Areas covered in this review: This review covers anti-aging strategies involving supplementation of dietary antioxidants such as polyphenols, vitamins E and C, lipoic acid, acetyl carnitine, carnosine and cysteine along with the application of mammalian target of rapamycin inhibitors and plasma membrane redox system activators. It also presents the use of different hormone supplementation, for example, melatonin, dehydroepiandrosterone, growth hormone and sex hormones as a tool against aging. The use of caloric restriction and calorie restriction mimetics as an anti-aging intervention is also reviewed.What the reader will gain: The concept, use and efficacy of different anti-aging approaches.Take home message: Despite a lot of research and sustained ongoing efforts, finding a viable anti-aging therapy which can extend the maximum human lifespan remains elusive. However, several interventions aimed towards a longer healthy life seem promising.

The Research Advances in Small Molecules Related With Delaying Aging*

Screening small molecules having anti-aging effect and researching the mechanism are of great practical significance for discovering new effective targets for treatment of age-related diseases and tumors, developing new drugs and promoting human health. What is more important is that these small molecules can be used as breakthrough points for the specific molecular mechanisms of aging, cancer and other biological phenomena via in-depth study. And this has an important role in promoting the development of molecular biology and other related life sciences. This article summarizes some representative anti-aging small molecules of the past decade or two and focuses on their molecular mechanisms.

Development of a bioassay to screen for chemicals mimicking the anti-aging effects of calorie restriction

Suppression of the growth hormone/insulin-like growth factor-I pathway in Ames dwarf (DF) mice, and caloric restriction (CR) in normal mice extends lifespan and delays the onset of age-related disorders. In combination, these interventions have an additive effect on lifespan in Ames DF mice. Therefore, common signaling pathways regulated by DF and CR could have additive effects on longevity. In this study, we tried to identity the signaling mechanism and develop a system to assess pro-longevity status in cells and mice. We previously identified genes up-regulated in the liver of DF and CR mice by DNA microarray analysis. Motif analysis of the upstream sequences of those genes revealed four major consensus sequence motifs, which have been named dwarfism and calorie restriction-responsive elements (DFCR-REs). One of the synthesized sequences bound to hepatocyte nuclear factor-4α (HNF-4α), an important transcription factor involved in liver metabolism. Furthermore, using this sequence information, we developed a highly sensitive bioassay to identify chemicals mimicking the anti-aging effects of CR. When the reporter construct, containing an element upstream of a secreted alkaline phosphatase (SEAP) gene, was co-transfected with HNF-4α and its regulator peroxisome proliferator-activated receptor (PPAR) γ coactivator-1α (PGC-1α), SEAP activity was increased compared with untransfected controls. Moreover, transient transgenic mice established using this construct showed increased SEAP activity in CR mice compared with ad libitum-fed mice. These data suggest that because of its rapidity, ease of use, and specificity, our bioassay will be more useful than the systems currently employed to screen for CR mimetics, which mimic the beneficial effects of CR. Our system will be particularly useful for high-throughput screening of natural and synthetic candidate molecules.

Bile acids extend longevity beyond calorie restriction

The discovery of potential anti-aging treatment capable of extending both our healthy aging and perhaps our longevity resuscitated an old human dream. It also brought about inordinate interest in these studies. While calorie restriction (CR) is still the best known intervention to increase life span, anti-aging molecules could mimic this effect without reducing nutrient intake. Such compounds, like rapamycin and spermidine, believed to be CR mimetic, have been discovered using the yeast Saccharomyces cerevisiae. The interest in such molecules stems from their universal action on others species including mammals [1]. In this issue of Aging, a study by Goldberg and colleagues presents an original screen designed to isolate molecules that further lengthen the life span of yeast under calorie restriction rather than imitating this effect [2]. In yeast, CR can be obtained by decreasing glucose concentration in the media. This intervention extends significantly chronological life span, i.e the time a yeast population remains viable in stationary phase [3]. By knocking-out peroxisomal proteins import (using a pex5Δ strain), the authors impaired beta-oxidation. As a consequence, the effects of CR on longevity are entirely abrogated. This genetic background was used to screen for chemical compounds that restore long life span under CR condition by targeting lipid metabolism. Among the chemical compounds identified, the authors focus on one group representing 6 bile acids compounds, the most efficient of them being lithocholic acid (LCA). Bile acids are mildly toxic oxidized derivatives of cholesterol that play important roles in lipid uptake by the intestine. Interestingly, none of the previously known small molecules that increase chronological life span in yeast (rapamycin, spermidine and methionine sulfoximine) were among the compounds that rescue the short longevity of pex5Δ under CR. While the effect of bile acids on life span was identified in a pex5Δ strain, LCA also extends the life span of wild type yeast by over two fold in glucose restricted medium as compared to regular medium. This observation suggests that LCA acts on a substrate active during calorie restriction. Although the mechanism by which bile acids increase life span is still unclear, Goldberg and colleagues provide several clues that shed light on this phenomenon. Among them, LCA treatment improves triacylglycerol-dependent lipid storage, increases stress resistance, and improves mitochondrial fitness. Using genetics, the authors found that the target of LCA is most likely inhibited by Tor1 signaling and partially regulated by cAMP/PKA/Rim15, two pathways known to regulate aging rate in yeast [4,5]. However, as yeasts do not synthesize bile acids, the mechanism of action of LCA has yet to be elucidated. Indeed, this study raises several interesting questions. Does LCA act as a pharmacological agent by binding a specific receptor in yeast or does it increase longevity by stimulating stress response due to its mild toxic effect (by hormesis)? Another question is whether bile acids or other related molecules can play an anti-aging role in metazoans. Current evidence from long-lived Little mice (Ghrhrlit/lit) and C. elegans proposes a role for bile acids in promoting longevity through a nuclear receptor mediated signaling [6,7]. If these xenobiotic molecules act through a universally conserved pathway from yeast to metazoans, it would make S. cerevisiae an unexpected model of choice to unravel this mechanism. Goldberg and colleagues open interesting and promising research to look for related compounds whose effectiveness would potentiate the longevity extension by calorie restricted diet. Studies in mammals will represent the real litmus test.

By increasing the level of cardiolipin in the inner mitochondrial membrane, a novel anti‐aging small molecule modulates many longevity‐ and disease‐related processes in mitochondria

We use the yeast Saccharomyces cerevisiae as a model to study the mechanisms by which age‐related changes in mitochondrial membrane lipids regulate longevity. We identified a novel anti‐aging small molecule, called LA, which increases the concentration of cardiolipin (CL) in the inner mitochondrial membrane. We: 1) assessed the effect of LA on the life spans of long‐ and short‐lived mutants lacking components of the mitochondrial fission, fusion, and tubulation machines or mitochondrial components involved in the biosynthesis of CL and phosphatidylethanolamine (PE); 2) examined how LA influences the chronology of numerous events characteristic of age‐related, mitochondria‐controlled apoptosis; 3) investigated the effect of LA on the susceptibility of yeast to exogenous pro‐apoptotic compounds targeting mitochondria; and 4) assessed the effect of LA on the age‐dependent dynamics of changes in mitochondrial oxygen consumption, membrane potential, and reactive oxygen species (ROS) generation. Our findings imply that: 1) by increasing CL stability and decreasing the “PE/CL” ratio within the mitochondrial membrane, LA specifically reorganizes the protein machines involved in mitochondrial fusion, fission, apoptosis, respiratory chain, and ROS production, thereby delaying aging; and 2) LA can be used for manipulating mitochondrial dysfunction in aging, neurodegeneration and cardiomyopathy.

Accelerated lung aging: a novel pathogenic mechanism of chronic obstructive pulmonary disease (COPD)

An enhanced or abnormal inflammatory response to the lungs to inhaled particles and gases, usually from cigarette smoke, is considered to be a general pathogenic mechanism in COPD (chronic obstructive pulmonary disease). Activation of leucocytes and the development of oxidant-antioxidant and protease-anti-protease imbalances are thought to be important aspects of this enhanced inflammatory response to cigarette smoke. The mechanisms involved in the perpetuation of the inflammatory response in the lungs in patients who develop COPD, even after smoking cessation, are not fully established and are key to our understanding of the pathogenic mechanisms in COPD and may be important for the development of new therapies. There is a relationship between chronic inflammatory diseases and aging, and the processes involved in aging may provide a novel mechanism in the pathogenesis of COPD. There is good evidence linking aging and COPD. During normal aging, pulmonary function deteriorates progressively and pulmonary inflammation increases, accompanied in the lungs by the features of emphysema. These features are accelerated in COPD. Emphysema is associated with markers of accelerated aging in the lungs, and COPD is also associated with features of accelerated aging in other organs, such as the cardiovascular and musculoskeletal systems. Cigarette smoke and other oxidative stresses result in cellular senescence and accelerate lung aging. There is also evidence that anti-aging molecules such as histone deacetylases and sirtuins are decreased in the lungs of COPD patients, compared with smokers without COPD, resulting in enhanced inflammation and further progression of COPD. The processes involved in accelerated aging may provide novel targets for therapy in COPD. The present article reviews the evidence for accelerated aging as a mechanism in the pathogenesis of COPD.

A mechanism linking lipid metabolism and longevity

We use the yeast Saccharomyces cerevisiae as a model to study the mechanisms linking lipid metabolism and longevity. Yeast aging can be slowed down by calorie restriction (CR), a low‐calorie diet that extends life span and delays age‐related disorders in a wide spectrum of organisms. We assessed the effect of CR and numerous mutations extending yeast life span on the spatiotemporal dynamics of the proteomes and lipidomes of organelles involved in lipid metabolism. These organelles include the endoplasmic reticulum (ER), peroxisomes and lipid bodies. Our findings imply that a calorie‐rich diet suppresses peroxisomal oxidation of free fatty acids (FFA) that originate from neutral lipids synthesized in the ER and deposited within lipid bodies. The resulting accumulation of FFA initiates several negative feedback loops regulating the metabolism of neutral lipids, ultimately leading to the accumulation of diacylglycerol (DAG). The buildup of FFA promotes necrotic cell death, whereas the accumulation of DAG hampers a stress response‐related signal transduction network. Implementing our knowledge, we identified five groups of novel anti‐aging small molecules that greatly extend yeast longevity by remodelling lipid metabolism in the ER, peroxisomes and lipid bodies and by promoting "mitohormesis" through the activation of a distinct set of stress response‐related processes in mitochondria.

Cyclin D1 Overexpression Permits the Reproducible Detection of Senescent Human Vascular Smooth Muscle Cells

The senescence of mitotic cells is hypothesized to play a causal role in organismal aging. Cultures of normal human cells become senescent in vitro as a result of a continuous decline in the mitotic fraction from cell turnover. However, one potential barrier to the evaluation of the frequency and distribution of senescent cells in tissues is the absence of a panel of robust markers for the senescent state. In parallel with an analysis of the growth kinetics of human vascular smooth muscle cells, we have undertaken transcriptomic comparisons of early- and late-passage cultures of human vascular smooth muscle cells to identify potential markers that can distinguish between senescent and growth-competent cells. A wide range of genes are upregulated at senescence in human vascular smooth muscle cells. In particular, we have identified a 12-fold upregulation of expression in the cyclin D1 message, which is reflected in a concomitant upregulation at the protein level. Quantitative cytochemical analysis of senescent and growing vascular smooth muscle cells indicates that cyclin D1 reactivity is a considerably better marker of replicative senescence than senescence-associated beta-galactosidase activity. We have applied this new marker (in combination with Ki67, COMET, and TUNEL staining) to the study of human vascular smooth muscle cells treated with resveratrol, a putative anti-aging molecule known to have significant effects on cell growth.

Reconstructed human skin: From photodamage to sunscreen photoprotection and anti-aging molecules

Acute or repetitive sun exposure has been shown to be responsible for various deletorious consequences such as sunburn reaction, photoaging and photocancers. Determination of early biological events occurring after UV exposure is essential for photoprotection. Using a human reconstructed skin in vitro, comprising both a fully differentiated epidermis and a living dermal equivalent, the effects of UVB and UVA were analysed in keratinocytes and fibroblasts. The efficiency of sunscreen protection was afforded after topical application. The effect of Vitamin C was analyzed. Reconstructed skin was exposed to UVB, UVA or SSR. Morphological aspect, DNA lesions, sunburn cells, MMP-1 were evaluated. Sunscreen photoprotection was assessed with formulations having different profile of absorption or photostability. Vitamin C was added to the culture medium during reconstruction of the skin. While UVB essentially induced direct epidermal damage such as DNA lesions or sunburn cells, UVA reached the dermis and led to alterations in fibroblasts and dermal extracellular matrix. Both UVB and UVA, alone or combined using solar simulated radiation (SSR), induced MMP-1 production, directly in dermal fibroblasts after UVA exposure, or through release of soluble epidermal factors after UVB. Based on the identification of these biological end-points, evaluation of sunscreeen photoprotection was performed after topical application of formulations. The data showed that broad UVB + UVA spectrum profile together with photostability are required for a real efficient protection. Finally, we found that Vitamin C could improve the morphogenesis of dermal epidermal junction, through its ability to promote synthesis of extracellular matrix and basement membrane proteins. These results may help in understanding the beneficial effects of such molecule in the treatment of photoaged skin. Altogether, these data emphazied the fact that human skin reconstructed in vitro is a valuable tool for research studies as well as for evaluation of compounds designed to prevent or correct photodamage.