Telomerase gene therapy ameliorates the effects of neurodegeneration associated to short telomeres in mice

Neurodegenerative diseases associated with old age such as Alzheimer's disease present major problems for society, and they currently have no cure. The telomere protective caps at the ends of chromosomes shorten with age, and when they become critically short, they can induce a persistent DNA damage response at chromosome ends, triggering secondary cellular responses such as cell death and cellular senescence. Mice and humans with very short telomeres owing to telomerase deficiencies have an earlier onset of pathologies associated with loss of the regenerative capacity of tissues. However, the effects of short telomeres in very low proliferative tissues such as the brain have not been thoroughly investigated. Here, we describe a mouse model of neurodegeneration owing to presence of short telomeres in the brain as the consequence of telomerase deficiency. Interestingly, we find similar signs of neurodegeneration in very old mice as the consequence of physiological mouse aging. Next, we demonstrate that delivery of telomerase gene therapy to the brain of these mice results in amelioration of some of these neurodegeneration phenotypes. These findings suggest that short telomeres contribute to neurodegeneration diseases with aging and that telomerase activation may have a therapeutic value in these diseases

Reply to Udroiu: Interesting mathematical analysis of telomere shortening rate and life span.

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Slower rates of accumulation of DNA damage in leukocytes correlate with longer lifespans across several species of birds and mammals.

Although there is previous evidence showing an increase in various types of DNA damage with aging in mice and humans, a comparative study determining accumulation rates of DNA double strand breaks, as determined by presence of phosphorylated histone H2AX (γH2AX), in leukocytes of individuals of different ages from phylogenetically distinct species from birds to mammals was lacking. Here, we demonstrate that the rate of accumulation of DNA damage as measured by the DNA damage marker γH2AX correlates with species longevity in dolphins, goats, reindeer, American flamingos, and griffon vultures. In particular, we find that species that show slower rates of accumulation of the DNA damage marker γH2AX also live longer.This Research was developed at Blasco lab, Spanish National Cancer Research Center, Institute of Health Carlos III, and is partially funded by the Spanish State Research Agency (AEI), Ministry of Science, Innovation and Universities, SAF2015-72455-EXP and SAF2013-45111-R, which is cofunded by EU-ERDF) and the Fundacion Botin (Spain). Partial funding was obtained from project CGL2016-80963-R (Ministerio Economia, Industria y Competividad).S

Telomere shortening rate predicts species life span.

Telomere shortening to a critical length can trigger aging and shorter life spans in mice and humans by a mechanism that involves induction of a persistent DNA damage response at chromosome ends and loss of cellular viability. However, whether telomere length is a universal determinant of species longevity is not known. To determine whether telomere shortening can be a single parameter to predict species longevities, here we measured in parallel the telomere length of a wide variety of species (birds and mammals) with very different life spans and body sizes, including mouse (Mus musculus), goat (Capra hircus), Audouin's gull (Larus audouinii), reindeer (Rangifer tarandus), griffon vulture (Gyps fulvus), bottlenose dolphin (Tursiops truncatus), American flamingo (Phoenicopterus ruber), and Sumatran elephant (Elephas maximus sumatranus). We found that the telomere shortening rate, but not the initial telomere length alone, is a powerful predictor of species life span. These results support the notion that critical telomere shortening and the consequent onset of telomeric DNA damage and cellular senescence are a general determinant of species life span.We thank the Madrid Zoo for all of their help and for providing the blood samples for a variety of species. We also thank Centro Nacional de Investigaciones Oncologicas (CNIO) (or "Spanish National Cancer Research Centre" in Madrid, Spain) confocal microscope core and animal facility, particularly Rosa Serrano, for all of their help and assistance, as well as the CNIO Bioinformatics Department, particularly Kevin Troule Lozano, for assistance with analysis. We thank the personnel from the Ebro Delta Natural Park and M. Garcia-Tarrason for sampling and facilities during fieldwork. We also thank Dr. Dani Oro (Centre d'Estudis Avancats de Blanes-Consejo Superior de Investigaciones Cientificas) for help with the ages of ringed Audouin's gulls. Partial funding was obtained from Project CGL2016-80963-R (Ministerio Economia, Industria y Competividad). We also thank Paula Martinez for assisting with revising the manuscript. Research in the M.A.B. laboratory is funded by the Spanish Ministry of Economy and Competitiveness Projects (SAF2013-45111-R and SAF2015-72455-EXP), the Comunidad de Madrid Project (S2017/BMD-3770), the World Cancer Research Project (16-1177), and the Fundacion Botin (Spain).S

A General Method to Discover Epitopes from Sera.

Antigen-antibody complexes are central players in an effective immune response. However, finding those interactions relevant to a particular disease state can be arduous. Nonetheless many paths to discovery have been explored since deciphering these interactions can greatly facilitate the development of new diagnostics, therapeutics, and vaccines. In silico B cell epitope mapping approaches have been widely pursued, though success has not been consistent. Antibody mixtures in immune sera have been used as handles for biologically relevant antigens, but these and other experimental approaches have proven resource intensive and time consuming. In addition, these methods are often tailored to individual diseases or a specific proteome, rather than providing a universal platform. Most of these methods are not able to identify the specific antibody's epitopes from unknown antigens, such as un-annotated neo antigens in cancer. Alternatively, a peptide library comprised of sequences unrestricted by naturally-found protein space provides for a universal search for mimotopes of an antibody's epitope. Here we present the utility of such a non-natural random sequence library of 10,000 peptides physically addressed on a microarray for mimotope discovery without sequence information of the specific antigen. The peptide arrays were probed with serum from an antigen-immunized rabbit, or alternatively probed with serum pre-absorbed with the same immunizing antigen. With this positive and negative screening scheme, we identified the library-peptides as the mimotopes of the antigen. The unique library peptides were successfully used to isolate antigen-specific antibodies from complete immune serum. Sequence analysis of these peptides revealed the epitopes in the immunized antigen. We present this method as an inexpensive, efficient method for identifying mimotopes of any antibody's targets. These mimotopes should be useful in defining both components of the antigen-antibody complex

Telomere shortening rate predicts species life span

Telomere shortening to a critical length can trigger aging and shorter life spans in mice and humans by a mechanism that involves induction of a persistent DNA damage response at chromosome ends and loss of cellular viability. However, whether telomere length is a universal determinant of species longevity is not known. To determine whether telomere shortening can be a single parameter to predict species longevities, here we measured in parallel the telomere length of a wide variety of species (birds and mammals) with very different life spans and body sizes, including mouse (Mus musculus), goat (Capra hircus), Audouin's gull (Larus audouinii), reindeer (Rangifer tarandus), griffon vulture (Gyps fulvus), bottlenose dolphin (Tursiops truncatus), American flamingo (Phoenicopterus ruber), and Sumatran elephant (Elephas maximus sumatranus). We found that the telomere shortening rate, but not the initial telomere length alone, is a powerful predictor of species life span. These results support the notion that critical telomere shortening and the consequent onset of telomeric DNA damage and cellular senescence are a general determinant of species life span

Analyses of anti-SMCfs serum pre-absorbed against SMCfs peptide.

<p><b>A. Validation of SMCfs antibody depletion from immune serum.</b> The serum-absorption steps (11or 20) refer to the number of iterative rounds of SMCfs-peptide or CP1-peptide absorption experiments conducted before application of the depleted serum to ELISA plates coated with SMCfs peptide. Error bar indicates SD of the duplication. <b>B. Signal intensity changes in anti-SMCfs serum binding following peptide-specific depletion.</b> The depleted immune sera samples were applied to the peptide array. Binding intensities to the 108 non-natural sequence peptides, which were shown to be selectively recognized by the original anti-SMCfs serum, are displayed as a heatmap for their visual comparison. There is an 850 fold difference between the lowest fluorescence intensity and the highest intensity. Four anti-SMCfs sera samples were applied to the peptide array, 1) non-absorbed anti-SMCfs serum, 2) anti-SMCfs serum absorbed 11x against SMCfs peptide, 3) anti-SMCfs serum absorbed 20x against SMCfs peptide, 4) anti-SMCfs serum absorbed 20x against the CP1 negative control peptide.</p

Motifs in common between RP1-4 and SMCfs as identified by the GLAM2 software.

<p>Motifs in common between RP1-4 and SMCfs as identified by the GLAM2 software.</p

ELISA determinations of anti-SMCfs sera binding to array-selected peptides.

<p><b>A. Immune serum.</b> Rabbit polyclonal anti-SMCfs serum was applied to the SMCfs peptide, four of the array-selected peptides, and a control peptide. The SMCfs peptide is the positive control. <b>B. Control serum.</b> Mouse polyclonal anti-KLH serum was applied to the same set of peptides described in A. The KLH is the positive control. Error bar indicates SD of the duplication.</p