Progress & prospects: gene therapy in aging

Will Life Extension Affect Our Social Judgments? Evidence That the Possibility of Indefinite Life Extension Increases Harshness Toward Social Transgressors

We tested the hypothesis that if indefinite life extension (ILE) through medical technologies were to become a reality, then people may become harsher in their judgment of social transgressors. In support of this hypothesis, we found that higher positive attitudes towards ILE technologies related to harshness in judgment of social transgressions (Study 1), and that making ILE plausible (compared to not plausible) led participants to endorse harsher punishments for social transgressors (Studies 2-3). We replicated this effect and found that it is not amplified by subliminal death primes, although the primes also increased harshness (Study 3). These results may have implications to understanding how social judgment may be affected by the prospect of ILE.

Mesenchymal stem cells conditioned with glucose depletion augments their ability to repair-infarcted myocardium

Mesenchymal stem cells (MSCs) are an attractive candidate for autologous cell therapy, but their ability to repair damaged myocardium is severely compromised with advanced age. Development of viable autologous cell therapy for treatment of heart failure in the elderly requires the need to address MSC ageing. In this study, MSCs from young (2 months) and aged (24 months) C57BL/6 mice were characterized for gene expression of IGF-1, FGF-2, VEGF, SIRT-1, AKT, p16(INK4a) , p21 and p53 along with measurements of population doubling (PD), superoxide dismutase (SOD) activity and apoptosis. Aged MSCs displayed senescent features compared with cells isolated from young animals and therefore were pre-conditioned with glucose depletion to enhance age affected function. Pre-conditioning of aged MSCs led to an increase in expression of IGF-1, AKT and SIRT-1 concomitant with enhanced viability, proliferation and delayed senescence. To determine the myocardial repair capability of pre-conditioned aged MSCs, myocardial infarction (MI) was induced in 24 months old C57BL/6 wild type mice and GFP expressing untreated and pre-conditioned aged MSCs were transplanted. Hearts transplanted with pre-conditioned aged MSCs showed increased expression of paracrine factors, such as IGF-1, FGF-2, VEGF and SDF-1α. This was associated with significantly improved cardiac performance as measured by dp/dt(max), dp/dt(min), LVEDP and LVDP, declined left ventricle (LV) fibrosis and apoptosis as measured by Masson's Trichrome and TUNEL assays, respectively, after 30 days of transplantation. In conclusion, pre-conditioning of aged MSCs with glucose depletion can enhance proliferation, delay senescence and restore the ability of aged cells to repair senescent infarcted myocardium.

We still have a long way to go to effectively deliver genes!

Gene therapy is emerging as a revolutionary alternative to conventional therapeutic approaches. However, its clinical application is still hampered by the lack of safe and effective gene delivery techniques. Among the plethora of diverse approaches used to ferry nucleic acids into target cells, non-viral vectors represent promising and safer alternatives to viruses and physical techniques. Both cationic lipids and polymers spontaneously wrap and shrink the genetic material in complexes named lipoplexes and polyplexes, respectively, thereby protecting it and shielding its negative charges. The development of non-viral vectors commenced more than two decades ago. Since then, some major classes of interesting molecules have been identified and modified to optimize their properties. However, the way towards the final goal of gene delivery, i.e. protein expression or gene silencing, is filled with obstacles and current non-viral carriers still have concerns about their overall efficiency. We strongly believe that the future of non-viral gene delivery relies on the development of multifunctional vectors specifically tailored with diverse functionalities that act more like viruses. Although these vectors are still a long way from clinical practice they are the ideal platform to effectively shuttle the genetic material to target cells in a safe and controlled way. In this review, after briefly introducing the basis of gene delivery and therapeutic applications we discuss the main polymeric and lipidic vectors utilized for gene delivery, focusing on the strategies adopted to overcome the major weaknesses inherent to their still limited activity, on the way towards ideal multifunctional vectors.

A role for the CISD2 gene in lifespan control and human disease

CISD2, the causative gene for Wolfram syndrome 2 (WFS2), is an evolutionarily conserved novel gene. Recently, we have demonstrated that CISD2 is involved in mammalian lifespan control; this work also establishes WFS2 as a mitochondria-mediated disorder and effectively links CISD2 gene function, mitochondrial integrity, and aging in mammals. In wild-type mice, the expression levels of CISD2 decrease in an age-dependent manner during the naturally aging process; this correlates with mitochondrial breakdown and parallels the development of an aged phenotype. Future work will examine how the CISD2 knockout mouse helps us to understand WFS2 pathogenesis, as well as exploring the potential effects of increased CISD2 expression. In addition, it will be of great interest to compare gene activity and/or protein function between normal human populations and long-lived centenarian groups. Together, human and mouse genetic studies should provide evidence as to whether CISD2 is a "master gene" for extreme old age.

Suitability of the clonal marbled crayfish for biogerontological research: a review and perspective, with remarks on some further crustaceans

This article examines the suitability of the parthenogenetic marbled crayfish for research on ageing and longevity. The marbled crayfish is an emerging laboratory model for development, epigenetics and toxicology that produces up to 400 genetically identical siblings per batch. It is easily cultured, has an adult size of 4-9 cm, a generation time of 6-7 months and a life span of 2-3 years. Experimental data and biological peculiarities like isogenicity, direct development, indeterminate growth, high regeneration capacity and negligible senescence suggest that the marbled crayfish is particularly suitable to investigate the dependency of ageing and longevity from non-genetic factors such as stochastic developmental variation, allocation of metabolic resources, damage and repair, caloric restriction and social stress. It is also well applicable to examine alterations of the epigenetic code with increasing age and to identify mechanisms that keep stem cells active until old age. As a representative of the sparsely investigated crustaceans and of animals with indeterminate growth and extended brood care the marbled crayfish may even contribute to evolutionary theories of ageing and longevity. Some relatives are recommended as substitutes for investigation of topics, for which the marbled crayfish is less suitable like genetics of ageing and achievement of life spans of decades under conditions of low food and low temperature. Research on ageing in the marbled crayfish and its relatives is of practical relevance for crustacean fisheries and aquaculture and may offer starting points for the development of novel anti-ageing interventions in humans.

Longevity mutants do not establish any "new science" of ageing

The biological reasons for ageing are now well known, so it is no longer an unsolved problem in biology. Furthermore, there is only one science of ageing, which is continually advancing. The significance and importance of the mutations that lengthen the lifespan of invertebrates can be assessed only in relationship to previous well-established studies of ageing. The mutant strains of model organisms that increase longevity have altered nutrient signalling pathways similar to the effects of dietary restriction, and so it is likely that there is a shift in the trade-off between reproduction and maintenance of the soma. To believe that the isolation and characterisation of a few invertebrate mutations (as well as those in yeast) will "galvanise" the field and provide new insights into human ageing is an extreme point of view which does not recognize the huge progress in ageing research that has been made in the last 50 years or so.

Human genetic variations: Beacons on the pathways to successful ageing

Avoiding age-related disease until late in life is key to 'successful' ageing. Over 300 genome-wide association study papers have been published. Over 50 variants have already been identified as associated with four key age-related diseases, namely cardiovascular disease, type 2 diabetes, osteoporosis and prostate cancer. We review these findings with reference to pathways linked to ageing, including cell cycle control or cell senescence, oxidative stress, insulin, IGF1 and other endocrine signalling, and inflammation. Many variants are disease specific or of unknown function. Of the remainder, those with functions likely to be relevant to ageing are predominantly in cell cycle control and therefore tissue repair. Three loci associated with two or more age-related diseases have been identified, two apparently related to cell cycle control. The third shared locus (near TERT), may be involved in telomerase activity and is associated with several environmentally caused age-related cancers. These findings challenge current ideas, suggesting large numbers of cell type specific effects, often driven by regulatory rather than coding changes. They also confirm the central role of cell cycle and re-growth as a key pathway underlying the human variation in successful ageing.