mTert induction in p21-positive cells counteracts capillary rarefaction and pulmonary emphysema

Lung diseases develop when telomeres shorten beyond a critical point. We constructed a mouse model in which the catalytic subunit of telomerase (mTert), or its catalytically inactive form (mTertCI), is expressed from the p21Cdkn1a locus. Expression of either TERT or TERTCI reduces global p21 levels in the lungs of aged mice, highlighting TERT non-canonical function. However, only TERT reduces accumulation of very short telomeres, oxidative damage, endothelial cell (ECs) senescence and senile emphysema in aged mice. Single-cell analysis of the lung reveals that p21 (and hence TERT) is expressed mainly in the capillary ECs. We report that a fraction of capillary ECs marked by CD34 and endowed with proliferative capacity declines drastically with age, and this is counteracted by TERT but not TERTCI. Consistently, only TERT counteracts decline of capillary density. Natural aging effects are confirmed using the experimental model of emphysema induced by VEGFR2 inhibition and chronic hypoxia. We conclude that catalytically active TERT prevents exhaustion of the putative CD34 + EC progenitors with age, thus protecting against capillary vessel loss and pulmonary emphysema.

Changes in patients’ religiosity related to dementia

Dementia is characterized by the presence of progressive cognitive and behavioral symptoms which affect normal functioning. With the purpose of determining if there are any changes related to patients’ religiosity due to dementia, we developed a questionnaire aiming to evaluate changes pre and post diagnostic. In effect, we observed that patients with dementia might experience a reduction of the importance given to religion and its associated practices with the disease progression. However, God’s belief did not show any changes despite the diagnosis. Therefore, we point out the relevance of incorporating religiosity as another aspect to take into account in the cognitive rehabilitation treatments.

The ALT pathway generates telomere fusions that can be detected in the blood of cancer patients

Telomere fusions (TFs) can trigger the accumulation of oncogenic alterations leading to malignant transformation and drug resistance. Despite their relevance in tumour evolution, our understanding of the patterns and consequences of TFs in human cancers remains limited. Here, we characterize the rates and spectrum of somatic TFs across >30 cancer types using whole-genome sequencing data. TFs are pervasive in human tumours with rates varying markedly across and within cancer types. In addition to end-to-end fusions, we find patterns of TFs that we mechanistically link to the activity of the alternative lengthening of telomeres (ALT) pathway. We show that TFs can be detected in the blood of cancer patients, which enables cancer detection with high specificity and sensitivity even for early-stage tumours and cancers of high unmet clinical need. Overall, we report a genomic footprint that enables characterization of the telomere maintenance mechanism of tumours and liquid biopsy analysis.

[Do we treat dementia of the Alzheimer type or Alzheimer's disease? Anti-dementia drugs in the era of biomarkers]

Approved drug treatments for Alzheimer´s disease (AD) are symptomatic and don´t modify the disease course. These include acetylcholinesterase inhibitors (AchI) and N-methyl-D-aspartate receptor antagonist, memantine. Around 20 years ago, these drugs were approved for Alzheimer type Dementia. This wasbased on clinical trials which inclusion criteria were focused on a clinical amnestic AD presentation. At that time, subjects with an atypical AD clinical presentation or biomarkers were not included in the pharmacological trials. New biomarkers that detect amyloid and neurodegeneration have allowed us to evaluate pathological changes compatible with AD. These new advances from aclinical and biomarkers perspective allowed a diagnostic criteria update; going from an exclusively clinical criteria to one that is hybrid: clinical presentation and biomarkers based criteria.New biomarkers facilitate the early diagnosis of AD and other dementias.However, they also generate new challenges and questions regarding the adequate pharmacological treatment.There is a need for clinical trials that evaluate anti-dementia drug’s efficacy based on current diagnostic criteria (clinical profile and biomarkers) and new practice guidelines. In addition, regulatory authorities should update ACHI and memantine indications.This will help doctors to prescribe the best possible treatment for this specific population without increasing risks.

["ZOOM effect". The TV sign in patients with dementia: Is there an increased incidence during pandemia due to a rise in isolation and virtuality?]

Delusional misidentification syndromes are misperceptions of external stimuli with an associated belief or elaboration that is held with delusional intensity. In the TV sign patient believes that the observed television events are occurring in a real three-dimensional space. It is one of the very rare forms of delusional misidentification syndrome in patients withdementia.Wereport7patientswithcognitiveimpairmentcaseswhohavepresentedTVsignduringtheCOVID-19 pandemic. Two patients had Alzheimer's dementia type diagnosis, 1 atypical Alzheimer dementia, 1 vascular dementia and 3 of them had mixed etiology (2 Alzheimer dementia + vascular and 1 dementia with Lewy bodies + vascular). Three presented other psychotic symptoms and 1 patient also had Capgras syndrome. These 7 cases series raise the possibility of an increase incidence of TV sign in patients with dementia during pandemia triggered by the rise in expo- sure to screen devices and a social isolation during this period.

Quality of life, mood, and cognitive performance in older adults with cognitive impairment during the first wave of COVID 19 in Argentina

BACKGROUND AND OBJECTIVES

In Argentina, government has established lockdown on 19 March 2020 to decrease SARS-COV-2 infection. The study aim was to understand how mandatory quarantine imposed due to COVID-19 pandemic has affected quality of life, mood, and cognitive performance of older adults with cognitive impairment.

DESIGN

Longitudinal descriptive-observational study.

PARTICIPANTS

Patients with cognitive impairment attending to online cognitive training sessions.

MEASUREMENTS

Participants have completed by themselves Quality of Life in Alzheimer's Disease scale (QOL-AD), Beck Depression Inventory (BDI-II), Test your Memory (TYM), and an attention and executive task created by our institution. Same assessments were done at the beginning of the lockdown and 7 months later.

RESULTS

Fifty-one adults were included. An increase in BDI-II score (p = 0.049) and worse performance in one of the executive attention tests (p = 0.012) have been found. No significant differences in QOL-AD, TYM, verbal fluency, or memory tests total scores have been observed. Reviewing scales subitems, differences in changes in sleep habits (p = 0.021), energy level decrease (p = 0.004), worse subjective record of memory capacity (p = 0.028), and decrease in ability to do housework (p = 0.007) have been shown. In those who lived alone, BDI and TYM higher scores in BDI-II (p = 0.030) (p = 0.022) have been found.

CONCLUSION

Mandatory quarantine imposed due to COVID-19 pandemic was associated with worsening of mood, some quality-of-life variables, and decrease in attention in older adults with cognitive impairment in Argentina.

Quality of life, mood and cognitive performance in older adults with cognitive impairment during the first wave of COVID 19 in Argentina

Background

In Argentina, government has established lock down on 19 March in order to decrease SARS‐COV 2 infection. These restrictions have remained effective for long time, with increase of anxiety depression and insomnia as shown in several studies. Older population was particularly at risk due to greater limitations to go out. Our objective was to evaluate the impact of confinement in quality of life, mood and cognitive performance of older adults with cognitive impairment.

Method

Longitudinal descriptive‐observational study. Patients with cognitive impairment (CDR 0.5‐1) attending to virtual cognitive stimulation sessions have participated. Participants have completed by themselves Quality of Life in Alzheimer's Disease scale (QOL AD), Beck Depression Inventory (BDI‐II), Test your Memory (TYM) and an attention and executive battery created by our institution. Same assessments were done at the beginning of the lock down and 7 months later. SPSS program was used and means, standard deviations and paired‐samples t test were calculated.

Result

51 adults (43 women, mean age: 68.53 SD: 8.06, mean education: 14.33 SD: 2.63) were included. An increase in BDI ‐II score (p = 0.049) and worse performance in one of the executive attention tests (p = 0.012) were found. No significant differences in total score of QOL‐AD (p = 0.090), TYM (p = 0.067), verbal fluency (p = 0.323) or memory tests (p = 0.098) were found. Reviewing sub items, differences in changes in sleep habits (p = 0.021), decrease in the energy level (p = 0.004), worse subjective record of memory capacity (p = 0.028) and decrease in ability to do housework (p = 0.007) were found. In those who lived alone a higher score in BDI ‐ II (p = 0.030) and TYM (p = 0.22) were found.

Conclusion

This is the first longitudinal study that measures the impact of lockdown on quality of life and cognitive performance in older adults with cognitive impairment in Argentina. Lockdown and isolation have shown worsening of mood and some quality of life variables and decrease in attention. Finally, our results show an increase in depressive symptoms in those patients who lived alone.

Medicinal herbs and nutritional supplements for dementia therapy: potential therapeutic targets and clinical evidence

Spices and herbs have been used for medicinal purposes for centuries. Also, in the last decades, the use of different nutritional supplements has been implemented to treat all kinds of diseases, including those that present an alteration in cognitive functioning. Dementia is a clinical syndrome in which a person's mental and cognitive capacities gradually decline. As the disease progresses, the person's autonomy diminishes. As there is not an effective treatment to prevent progressive deterioration in many of these pathologies, nutritional interventions have been, and still are, one of the most widely explored therapeutic possibilities. In this review, we have discussed a great number of potentially interesting plants, nutritional derivatives and probiotics for the treatment of dementia around the world. Their action mechanisms generally involve neuroprotective effects via anti-inflammatory, antioxidant, anti-apoptotic, b-amyloid and tau anti-aggregate actions; brain blood flow improvement, and effects on synaptic cholinergic and dopaminergic neurotransmission, which may optimize cognitive performance in patients with cognitive impairment. As for their efficacy in patients with cognitive impairment and/or dementias, evidence is still scarce and/or their outcomes are controversial. We consider that many of these substances have promising therapeutic properties. Therefore, the scientific community has to continue with a more complete research focused on both identifying possible action mechanisms and carrying out clinical trials, preferably randomized double-blind ones, with a greater number of patients, a long-term follow-up, dose standardization and the use of current diagnosis criteria.

NLRP3 inflammasome suppression improves longevity and prevents cardiac aging in male mice

While NLRP3‐inflammasome has been implicated in cardiovascular diseases, its role in physiological cardiac aging is largely unknown. During aging, many alterations occur in the organism, which are associated with progressive impairment of metabolic pathways related to insulin resistance, autophagy dysfunction, and inflammation. Here, we investigated the molecular mechanisms through which NLRP3 inhibition may attenuate cardiac aging. Ablation of NLRP3‐inflammasome protected mice from age‐related increased insulin sensitivity, reduced IGF‐1 and leptin/adiponectin ratio levels, and reduced cardiac damage with protection of the prolongation of the age‐dependent PR interval, which is associated with atrial fibrillation by cardiovascular aging and reduced telomere shortening. Furthermore, old NLRP3 KO mice showed an inhibition of the PI3K/AKT/mTOR pathway and autophagy improvement, compared with old wild mice and preserved Nampt‐mediated NAD⁺ levels with increased SIRT1 protein expression. These findings suggest that suppression of NLRP3 prevented many age‐associated changes in the heart, preserved cardiac function of aged mice and increased lifespan.

Association of COMT Val158Met Polymorphism with Psychopathological Symptoms in Patients with Eating Disorders

BACKGROUND

Dopamine physiological functions make dopaminergic genes suitable candidates for association studies in eating disorders (ED). A Val158Met polymorphism in the catechol-O-methyltransferase (COMT) gene, which is involved in dopamine degradation, has been studied in relation to ED.

OBJECTIVE

We aimed to analyze the association between this polymorphism and general psychopathological symptoms that are often coupled to these disorders.

METHOD

A total of 303 ED patients, diagnosed according to DSM-5 criteria, completed the SCL-90R questionnaire and were genotyped for the Val158Met polymorphism.

RESULTS

There were significant differences in the global indices of the SCL-90R inventory between the three ED groups (Anorexia Nervosa (AN), Bulimia Nervosa (BN) and binge-eating disorder; ANOVA-p < 0.05). Females with BN showed the highest scores (worse symptomatology) of all participants. In this group, a gene-dose effect was observed on the psychometric evaluation of the patients, as Val/Val carriers displayed the highest scores for all the SCL-90R scales, followed by Val/Met and then Met/Met carriers. Significant differences between genotypes were observed in the Obsessive- Compulsive (p = 0.018), Paranoid Ideation (p = 0.0005) and Psychoticism (p = 0.039) scales, as well as in the PSDI (p = 0.014) general index.

CONCLUSION

The results taken together suggest that COMT genetic variability may contribute to general psychopathological symptoms in patients with BN.

Downregulation of mTOR Signaling Increases Stem Cell Population Telomere Length during Starvation of Immortal Planarians

Reduction of caloric intake delays and prevents age-associated diseases and extends the life span in many organisms. It may be that these benefits are due to positive effects of caloric restriction on stem cell function. We use the planarian model Schmidtea mediterranea, an immortal animal that adapts to long periods of starvation by shrinking in size, to investigate the effects of starvation on telomere length. We show that the longest telomeres are a general signature of planarian adult stem cells. We also observe that starvation leads to an enrichment of stem cells with the longest telomeres and that this enrichment is dependent on mTOR signaling. We propose that one important effect of starvation for the rejuvenation of the adult stem cell pool is through increasing the median telomere length in somatic stem cells. Such a mechanism has broad implications for how dietary effects on aging are mediated at the whole-organism level.

[Head turn sign as a marker of dementia diagnosis]

Due to the phenomenon of ageing population, cognitive impairment has become more prevalent, and any marker able to improve its detection becomes of significant importance. With that objective in mind, a prospective observational study was performed in a medical consultation related to cognitive impairment. 150 subjects (58% women) were included with an average age of 76 years (SD 8.6). The Head Turn sign was positive for 32 subjects with a sensitivity of 41.7% for dementia, a specificity of 93.7% and a negative predictive value of 64.4%. This study shows the semiologic value of a simple clinical sign, easy to spot in the daily practice and most helpful to alert physicians about a likely dementia diagnosis.

Telomeres and telomerase in heart regeneration

Although recent advances have overturned the old view of the human heart as an inert postmitotic organ, it is clear that the adult heart´s capacity to regenerate after an ischemic episode is very limited. Unlike humans, zebrafish and other lower vertebrates vigorously regenerate damaged myocardium after cardiac injury. Understanding how the zebrafish is able to conserve life-long cardiac regeneration capacity while mammals lose it soon after birth is crucial for the development of new treatments for myocardial infarction. Mammals and lower vertebrates differ markedly in their rates of cardiomyocyte proliferation and levels of telomerase activity. Here, we review recent discoveries identifying lack of telomerase activity and concomitant telomere dysfunction as natural barriers to cardiomyocyte proliferation and cardiac regeneration.

Telomere Length Defines the Cardiomyocyte Differentiation Potency of Mouse Induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) can be differentiated in vitro and in vivo to all cardiovascular lineages and are therefore a promising cell source for cardiac regenerative therapy. However, iPSC lines do not all differentiate into cardiomyocytes (CMs) with the same efficiency. Here, we show that telomerase-competent iPSCs with relatively long telomeres and high expression of the shelterin-complex protein TRF1 (iPSC^highT ) differentiate sooner and more efficiently into CMs than those with relatively short telomeres and low TRF1 expression (iPSC^lowT ). Ascorbic acid, an enhancer of cardiomyocyte differentiation, further increases the cardiomyocyte yield from iPSC^highT but does not rescue the cardiomyogenic potential of iPSC^lowT . Interestingly, although iPSCs^lowT differentiate very poorly to the mesoderm and endoderm lineages, they differentiate very efficiently to the ectoderm lineage, indicating that cell fate can be determined by in vitro selection of iPSCs with different telomere content. Our findings highlight the importance of selecting iPSCs with ample telomere reserves in order to generate high numbers of CMs in a fast, reliable, and efficient way. Stem Cells 2017;35:362-373.

Mitochondrial and nuclear DNA matching shapes metabolism and healthy ageing

Human mitochondrial DNA (mtDNA) shows extensive within population sequence variability. Many studies suggest that mtDNA variants may be associated with ageing or diseases, although mechanistic evidence at the molecular level is lacking. Mitochondrial replacement has the potential to prevent transmission of disease-causing oocyte mtDNA. However, extension of this technology requires a comprehensive understanding of the physiological relevance of mtDNA sequence variability and its match with the nuclear-encoded mitochondrial genes. Studies in conplastic animals allow comparison of individuals with the same nuclear genome but different mtDNA variants, and have provided both supporting and refuting evidence that mtDNA variation influences organismal physiology. However, most of these studies did not confirm the conplastic status, focused on younger animals, and did not investigate the full range of physiological and phenotypic variability likely to be influenced by mitochondria. Here we systematically characterized conplastic mice throughout their lifespan using transcriptomic, proteomic,metabolomic, biochemical, physiological and phenotyping studies. We show that mtDNA haplotype profoundly influences mitochondrial proteostasis and reactive oxygen species generation,insulin signalling, obesity, and ageing parameters including telomere shortening and mitochondrial dysfunction, resulting in profound differences in health longevity between conplastic strains.

Postnatal telomere dysfunction induces cardiomyocyte cell-cycle arrest through p21 activation

The molecular mechanisms that drive mammalian cardiomyocytes out of the cell cycle soon after birth remain largely unknown. Here, we identify telomere dysfunction as a critical physiological signal for cardiomyocyte cell-cycle arrest. We show that telomerase activity and cardiomyocyte telomere length decrease sharply in wild-type mouse hearts after birth, resulting in cardiomyocytes with dysfunctional telomeres and anaphase bridges and positive for the cell-cycle arrest protein p21. We further show that premature telomere dysfunction pushes cardiomyocytes out of the cell cycle. Cardiomyocytes from telomerase-deficient mice with dysfunctional telomeres (G3 Terc(-/-)) show precocious development of anaphase-bridge formation, p21 up-regulation, and binucleation. In line with these findings, the cardiomyocyte proliferative response after cardiac injury was lost in G3 Terc(-/-) newborns but rescued in G3 Terc(-/-)/p21(-/-) mice. These results reveal telomere dysfunction as a crucial signal for cardiomyocyte cell-cycle arrest after birth and suggest interventions to augment the regeneration capacity of mammalian hearts.

Telomerase Is Essential for Zebrafish Heart Regeneration

After myocardial infarction in humans, lost cardiomyocytes are replaced by an irreversible fibrotic scar. In contrast, zebrafish hearts efficiently regenerate after injury. Complete regeneration of the zebrafish heart is driven by the strong proliferation response of its cardiomyocytes to injury. Here we show that, after cardiac injury in zebrafish, telomerase becomes hyperactivated, and telomeres elongate transiently, preceding a peak of cardiomyocyte proliferation and full organ recovery. Using a telomerase-mutant zebrafish model, we found that telomerase loss drastically decreases cardiomyocyte proliferation and fibrotic tissue regression after cryoinjury and that cardiac function does not recover. The impaired cardiomyocyte proliferation response is accompanied by the absence of cardiomyocytes with long telomeres and an increased proportion of cardiomyocytes showing DNA damage and senescence characteristics. These findings demonstrate the importance of telomerase function in heart regeneration and highlight the potential of telomerase therapy as a means of stimulating cell proliferation upon myocardial infarction.

Impact of NEGR1 genetic variability on psychological traits of patients with eating disorders

Genetics variants in the NEGR1 gene, strongly expressed in the brain, have been reported to affect the neuronal control of food intake therefore inducing obesity. With the same rationale, we hypothesized that this genetic variability may be associated with psychological traits commonly displayed by eating disorder (ED) patients and/or with the risk for the disorder. We analyzed 21 tag-single-nucleotide polymorphisms (SNPs) in the coding sequence and adjacent regions of the NEGR1 gene. A total of 169 ED patients (106 with anorexia nervosa (AN) and 63 with bulimia nervosa (BN)) and 312 healthy subjects were genotyped. Personality traits and general psychopathological symptoms were assessed by the Eating Disorders Inventory Test-2 (EDI-2) and Symptom Checklist 90 Revised inventories. None of the SNPs or haplotypes analyzed were associated with a greater risk of ED or correlated with anthropometric parameters. However, in patients with BN, four SNPs (rs12740031, rs10789322, rs6659202 and rs591540) correlated with the scores in Drive for Thinness (DT), Ineffectiveness (I) and Interoceptive Awareness (IA) (Bonferroni-P<0.05 in all instances). The first two SNPs along with rs954299 and rs2422021 formed a haplotype block, which showed a consistent association with the EDI-2 score in BN patients (Bonferroni-P=0.01). A subsequent three-SNP sliding-window approach identified a central area, encompassing both the haplotype block and the individually relevant SNPs that strongly correlated with the scores of BN patients in DT, I, IA and Bulimia. No associations were identified in the AN group. These preliminary results indicate that NEGR1 could be an important locus influencing certain personality dimensions in BN patients.

Iron modulates cell survival in a Ras- and MAPK-dependent manner in ovarian cells

Ovarian cancer is a leading cause of cancer death in women in the United States. While the majority of ovarian cancers are serous, some rarer subtypes (i.e. clear cell) are often associated with endometriosis, a benign gynecological disease. Iron is rich in the cyst fluid of endometriosis-associated ovarian cancers and induces persistent oxidative stress. The role of iron, an essential nutrient involved in multiple cellular functions, in normal ovarian cell survival and ovarian cancer remains unclear. Iron, presented as ferric ammonium citrate (FAC), dramatically inhibits cell survival in ovarian cancer cell types associated with Ras mutations, while it is without effect in immortalized normal ovarian surface epithelial (T80) and endometriotic epithelial cells (lacking Ras mutations). Interestingly, FAC induced changes in cytoplasmic vacuolation concurrently with increases in LC3-II levels (an autophagy marker); these changes occurred in an ATG5/ATG7-dependent, beclin-1/hVps34-independent, and Ras-independent manner. Knockdown of autophagy mediators in HEY ovarian cancer cells reversed FAC-induced LC3-II levels, but there was little effect on reversing the cell death response. Intriguingly, transmission electron microscopy of FAC-treated T80 cells demonstrated abundant lysosomes (confirmed using Lysotracker) rich in iron particles, which occurred in a Ras-independent manner. Although the mitogen-activated protein kinase (MAPK) inhibitor, U0126, reversed FAC-induced LC3-II/autophagic punctae and lysosomes in a Ras-independent manner, it was remarkable that U0126 reversed cell death in malignant ovarian cells associated with Ras mutations. Moreover, FAC increased heme oxygenase-1 expression in H-Ras-overexpressing T80 cells, which was associated with increased cell death when overexpressed in T80 cells. Disruption of intracellular iron levels, via chelation of intracellular iron (deferoxamine), was also detrimental to malignant ovarian cell survival; thus, homeostatic intracellular iron levels are essential for cell survival. Collectively, our results implicate iron in modulating cell death in a Ras- and MAPK-dependent manner in ovarian cancer cells.

Injection of irradiated b16 melanoma genetically-modified to secrete IFN-alpha causes regression of an established tumor

Highly aggressive murine B16 melanoma was engineered to secrete IFN-alpha constitutively. Cells expressing IFN-alpha were injected into syngeneic C57BL/6 mice and the mice were monitored for tumor development. Secretion of IFN-alpha by B16 melanoma cells completely abrogated their tumorigenicity in syngeneic mice. LFN-alpha-secreting cells also abrogated the tumorigenicity of IFN-gamma-secreting and TNF-alpha-secreting cells when injected in combination whereas cells secreting either IFN-gamma or TNF-alpha grow progressively in mice when injected alone. Moreover, protected animals developed significant immunity against subsequent challenge with parental cells. Injection of parental cells and IFN-alpha-secreting cells together in a mixed tumor transplantation assay resulted in a significant reduction of tumorigenicity of the parental cells. Histopathological studies of the tissues from the injection site of the mice inoculated with a combination of parental and B16.IFN-alpha cells revealed the existence of a massive cellular infiltrate composed of lymphocytes and granulocytes at an early stage (7-11 days). In the later stages (22 days), no recognizable tumor tissue was detected. Injection of irradiated IFN-alpha-secreting cells in the mice carrying an established tumor completely prevented tumor development in 80% of the treated mice when injection was performed on the same side as the tumors. Injection of irradiated IFN-alpha-secreting cells in the contralateral site showed much less effect on the established tumor. Systemic antitumor effects on the established tumor can be enhanced by using a combination of irradiated IFN-alpha and IFN-gamma secreting cells as a vaccinating inoculum.

Emulsifying Properties of Chemically Deamidated Corn (Zea Mays) Gluten Meal

Corn gluten meal is a by-product of starch production that is readily available. Corn protein isolates have limited applications due to their hydrophobic nature, low solubility and limited functionality as emulsifiers. In this study, a mild acidic treatment of corn gluten meal was performed in order to achieve deamidation of asparagine and glutamine residues and modify the interfacial behavior of this byproduct. A 0.1 N HCl treatment for 6 h at 70 °C rendered a deamidation degree of 20.4%, which increased the emulsification activity index of corn gluten meal from 6.8 to 16.8 m2/g protein, with a remarkable increase in emulsion stability from 0 to 90.6% oil retention. Proteins participating in the emulsion were separated by SDS-PAGE and the main polypeptides were identified as alpha and beta-zeins. After deamidation, protein dissociation and unfolding due to the obtained negative charges resulted in enhanced functionality.

The role of telomeres and telomerase in stem cell aging

Stem cells regenerate our bodies. In a similar manner to match ignition, stem cell "ignition" has to be precisely tuned to avoid uncontrolled proliferation as may occur in tumors or, inversely, the lack of proliferation as happens in degenerative disorders. During the last years it has become evident that telomeres and telomerase are main components of the stem cell "ignition" mechanism, providing a way to restrain cancer and delay aging.

A p53-dependent response limits epidermal stem cell functionality and organismal size in mice with short telomeres

Telomere maintenance is essential to ensure proper size and function of organs with a high turnover. In particular, a dwarf phenotype as well as phenotypes associated to premature loss of tissue regeneration, including the skin (hair loss, hair graying, decreased wound healing), are found in mice deficient for telomerase, the enzyme responsible for maintaining telomere length. Coincidental with the appearance of these phenotypes, p53 is found activated in several tissues from these mice, where is thought to trigger cellular senescence and/or apoptotic responses. Here, we show that p53 abrogation rescues both the small size phenotype and restitutes the functionality of epidermal stem cells (ESC) of telomerase-deficient mice with dysfunctional telomeres. In particular, p53 ablation restores hair growth, skin renewal and wound healing responses upon mitogenic induction, as well as rescues ESCmobilization defects in vivo and defective ESC clonogenic activity in vitro. This recovery of ESC functions is accompanied by a downregulation of senescence markers and an increased proliferation in the skin and kidney of telomerase-deficient mice with critically short telomeres without changes in apoptosis rates. Together, these findings indicate the existence of a p53-dependent senescence response acting on stem/progenitor cells with dysfunctional telomeres that is actively limiting their contribution to tissue regeneration, thereby impinging on tissue fitness.

A GRFa2/Prop1/stem (GPS) cell niche in the pituitary

BACKGROUND

The adult endocrine pituitary is known to host several hormone-producing cells regulating major physiological processes during life. Some candidates to progenitor/stem cells have been proposed. However, not much is known about pituitary cell renewal throughout life and its homeostatic regulation during specific physiological changes, such as puberty or pregnancy, or in pathological conditions such as tumor development.

PRINCIPAL FINDINGS

We have identified in rodents and humans a niche of non-endocrine cells characterized by the expression of GFRa2, a Ret co-receptor for Neurturin. These cells also express b-Catenin and E-cadherin in an oriented manner suggesting a planar polarity organization for the niche. In addition, cells in the niche uniquely express the pituitary-specific transcription factor Prop1, as well as known progenitor/stem markers such as Sox2, Sox9 and Oct4. Half of these GPS (GFRa2/Prop1/Stem) cells express S-100 whereas surrounding elongated cells in contact with GPS cells express Vimentin. GFRa2+-cells form non-endocrine spheroids in culture. These spheroids can be differentiated to hormone-producing cells or neurons outlining the neuroectoderm potential of these progenitors. In vivo, GPSs cells display slow proliferation after birth, retain BrdU label and show long telomeres in its nuclei, indicating progenitor/stem cell properties in vivo.

SIGNIFICANCE

Our results suggest the presence in the adult pituitary of a specific niche of cells characterized by the expression of GFRa2, the pituitary-specific protein Prop1 and stem cell markers. These GPS cells are able to produce different hormone-producing and neuron-like cells and they may therefore contribute to postnatal pituitary homeostasis. Indeed, the relative abundance of GPS numbers is altered in Cdk4-deficient mice, a model of hypopituitarism induced by the lack of this cyclin-dependent kinase. Thus, GPS cells may display functional relevance in the physiological expansion of the pituitary gland throughout life as well as protection from pituitary disease.

Telomerase reverse transcriptase delays aging in cancer-resistant mice

Telomerase confers limitless proliferative potential to most human cells through its ability to elongate telomeres, the natural ends of chromosomes, which otherwise would undergo progressive attrition and eventually compromise cell viability. However, the role of telomerase in organismal aging has remained unaddressed, in part because of the cancer-promoting activity of telomerase. To circumvent this problem, we have constitutively expressed telomerase reverse transcriptase (TERT), one of the components of telomerase, in mice engineered to be cancer resistant by means of enhanced expression of the tumor suppressors p53, p16, and p19ARF. In this context, TERT overexpression improves the fitness of epithelial barriers, particularly the skin and the intestine, and produces a systemic delay in aging accompanied by extension of the median life span. These results demonstrate that constitutive expression of Tert provides antiaging activity in the context of a mammalian organism.

Nuclear envelope defects cause stem cell dysfunction in premature-aging mice

Nuclear lamina alterations occur in physiological aging and in premature aging syndromes. Because aging is also associated with abnormal stem cell homeostasis, we hypothesize that nuclear envelope alterations could have an important impact on stem cell compartments. To evaluate this hypothesis, we examined the number and functional competence of stem cells in Zmpste24-null progeroid mice, which exhibit nuclear lamina defects. We show that Zmpste24 deficiency causes an alteration in the number and proliferative capacity of epidermal stem cells. These changes are associated with an aberrant nuclear architecture of bulge cells and an increase in apoptosis of their supporting cells in the hair bulb region. These alterations are rescued in Zmpste24^−/−Lmna^+/− mutant mice, which do not manifest progeroid symptoms. We also report that molecular signaling pathways implicated in the regulation of stem cell behavior, such as Wnt and microphthalmia transcription factor, are altered in Zmpste24^−/− mice. These findings establish a link between age-related nuclear envelope defects and stem cell dysfunction.

The longest telomeres: a general signature of adult stem cell compartments

Identification of adult stem cells and their location (niches) is of great relevance for regenerative medicine. However, stem cell niches are still poorly defined in most adult tissues. Here, we show that the longest telomeres are a general feature of adult stem cell compartments. Using confocal telomere quantitative fluorescence in situ hybridization (telomapping), we find gradients of telomere length within tissues, with the longest telomeres mapping to the known stem cell compartments. In mouse hair follicles, we show that cells with the longest telomeres map to the known stem cell compartments, colocalize with stem cell markers, and behave as stem cells upon treatment with mitogenic stimuli. Using K15-EGFP reporter mice, which mark hair follicle stem cells, we show that GFP-positive cells have the longest telomeres. The stem cell compartments in small intestine, testis, cornea, and brain of the mouse are also enriched in cells with the longest telomeres. This constitutes the description of a novel general property of adult stem cell compartments. Finally, we make the novel finding that telomeres shorten with age in different mouse stem cell compartments, which parallels a decline in stem cell functionality, suggesting that telomere loss may contribute to stem cell dysfunction with age.

Telomerase reverses epidermal hair follicle stem cell defects and loss of long-term survival associated with critically short telomeres

Organ homeostasis and organismal survival are related to the ability of stem cells to sustain tissue regeneration. As a consequence of accelerated telomerase shortening, telomerase-deficient mice show defective tissue regeneration and premature death. This suggests a direct impact of telomere length and telomerase activity on stem cell biology. We recently found that short telomeres impair the ability of epidermal stem cells to mobilize out of the hair follicle (HF) niche, resulting in impaired skin and hair growth and in the suppression of epidermal stem cell proliferative capacity in vitro. Here, we demonstrate that telomerase reintroduction in mice with critically short telomeres is sufficient to correct epidermal HF stem cell defects. Additionally, telomerase reintroduction into these mice results in a normal life span by preventing degenerative pathologies in the absence of increased tumorigenesis.

Delayed ageing through damage protection by the Arf/p53 pathway

The tumour-suppressor pathway formed by the alternative reading frame protein of the Cdkn2a locus (Arf) and by p53 (also called Trp53) plays a central part in the detection and elimination of cellular damage, and this constitutes the basis of its potent cancer protection activity. Similar to cancer, ageing also results from the accumulation of damage and, therefore, we have reasoned that Arf/p53 could have anti-ageing activity by alleviating the load of age-associated damage. Here we show that genetically manipulated mice with increased, but otherwise normally regulated, levels of Arf and p53 present strong cancer resistance and have decreased levels of ageing-associated damage. These observations extend the protective role of Arf/p53 to ageing, revealing a previously unknown anti-ageing mechanism and providing a rationale for the co-evolution of cancer resistance and longevity.

Genetic analysis of myc and telomerase interactions in vivo

Myc is a transcription factor with pleiotropic effects on tumorigenesis which are likely to be mediated by its target genes. A known Myc transcriptional target is the catalytic subunit of telomerase, Tert. However, the contribution of Tert activation to Myc-induced tumorigenesis in vivo remains unknown. In this study, we addressed the role of telomerase in Myc-induced skin papillomatosis by using compound mice with a switchable Myc gene, Inv-MycERTAM mice, in combination with either telomerase deficiency (Terc-/-) or telomerase overexpression (K5-mTert) in the skin. We first demonstrated that Myc activates telomerase in the skin. With Inv-MycERTAM x Terc-/- mice, we further showed that this telomerase activation is partially required to elicit a full hyperplastic Myc-induced response. The presence of critically short telomeres in late-generation Inv-MycERTAM x Terc-/- mice further reduced the skin lesion induced by Myc. On the other hand, telomerase overexpression in the skin of K5-mTert mice augments Myc-induced hyperplasia in the absence of changes in telomere length, suggesting a direct role of telomerase in the Myc protumorigenic response. Taken together, these results highlight telomerase as a mediator of Myc-induced papillomatosis and suggest telomerase as a putative therapeutic target for Myc-dependent lesions.

Telomerase regulation and stem cell behaviour

Telomerase expression is restricted to a few cell types of the adult organism, most notably germ cells and stem/progenitor cells. Telomerase activity in germ cells is sufficient to prevent telomere shortening with age. Stem cells, however, do not have sufficient telomerase to prevent telomere shortening associated with continuous tissue renewal with increasing age. Indeed, telomerase levels in the adult organism are thought to be rate-limiting for longevity. This is supported by rare human syndromes caused by mutations in telomerase components, which are characterized by premature loss of tissue renewal and premature death. More recently, the role of telomerase and telomere length in stem cells is starting to be elucidated.

Immunostimulation of white shrimp (Litopenaeus vannamei) following dietary administration of Ergosan

Ergosan an algal product containing 1% alginic acid, developed for use in aquaculture and reported to have immunomodulatory activity, was administered orally to intermoult adult white shrimp (Litopenaeus vannamei) for 15 days. Examination of haemolymph proteins using SDS-PAGE did not reveal any obvious differences between control and Ergosan treated shrimp. Similarly, total haemocyte counts were found to be roughly equivalent for both the control and experimental samples. However, differential analysis of haemocyte populations revealed marked changes in terms of the relative levels of hyaline, semi-granular, and particularly granular haemocytes between the two groups. Moreover, enhancement of the in vitro antimicrobial activity of haemolymph towards two shrimp pathogenic Vibrio isolates was recorded for shrimp fed with Ergosan. Finally, shrimp fed with Ergosan showed a significant increase in relative growth when compared with control groups.

Effects of telomerase and telomere length on epidermal stem cell behavior

A key process in organ homeostasis is the mobilization of stem cells out of their niches. We show through analysis of mouse models that telomere length, as well as the catalytic component of telomerase, Tert, are critical determinants in the mobilization of epidermal stem cells. Telomere shortening inhibited mobilization of stem cells out of their niche, impaired hair growth, and resulted in suppression of stem cell proliferative capacity in vitro. In contrast, Tert overexpression in the absence of changes in telomere length promoted stem cell mobilization, hair growth, and stem cell proliferation in vitro. The effects of telomeres and telomerase on stem cell biology anticipate their role in cancer and aging.

Defining the temporal requirements for Myc in the progression and maintenance of skin neoplasia

The homeostatic integrity of skin epidermis is maintained by a balance between keratinocyte proliferation, on one hand, and terminal differentiation combined with outward migration and shedding, on the other. Perturbation of this balance in favor of proliferation can result in hyperplasia and, potentially, tumorigenesis. We have previously described a reversible transgenic mouse model of epidermal neoplasia in which expression of an acutely regulatable form of Myc, MycERTAM, is targeted to epidermis via the involucrin promoter. In this model, sustained activation of MycERTAM induces a complex neoplastic lesion involving marked hyperplasia of less-differentiated suprabasal cells, angiogenesis and overt papillomatosis. Subsequent deactivation of MycERTAM triggers complete papilloma regression. Here, we provide evidence that Myc-induced papillomas are self-limiting because of the eventual differentiation of MycERTAM-expressing keratinocytes. Thus, keratinocyte differentiation eventually prevails over Myc-induced proliferation. We also show that regression of Myc-induced papillomas following MycERTAM deactivation occurs through a combination of growth arrest and irreversible differentiation. Finally, we demonstrate that transient deactivation of Myc is sufficient to expel keratinocytes irreversibly from the proliferative compartment and render them refractory to the mitogenic influence of subsequent Myc reactivation. Such observations illustrate the potential utility of even short-term inhibition of oncogenic lesions in the treatment of cancer.

Cloning and expression of Blo t 1, a novel allergen from the dust mite Blomia tropicalis, homologous to cysteine proteases

BACKGROUND

House dust mite allergens have been shown to be a very important stimulus in the causation of asthma and triggers for the exacerbation of symptoms. Therefore, characterization of mite-derived allergens at the molecular level is an important step for the development of effective diagnostic and therapeutic approaches, as well as for epidemiological studies.

OBJECTIVE

To clone, express and characterize at the molecular level the cysteine protease from Blomia tropicalis (Bt).

METHODS

A full-length cDNA encoding Blo t 1 was cloned from a Bt cDNA library using a PCR and RACE-based strategy. The cDNA was PCR-amplified, sequenced and subcloned into a prokaryotic expression vector. The allergenicity of the recombinant Blo t 1 was evaluated for IgE reactivity by Western blot.

RESULTS

Blo t 1 cDNA encodes a 221 amino acids polypeptide with an estimated molecular weight of 25 kDa. The recombinant protein is 35% identical to other mite cysteine proteases. Recombinant Blo t 1 (rBlo t 1) bound IgE from 62% of Bt skin test-positive serum. Dermatophagoides pteronyssinus (Dp) skin test-positive sera did not react with rBlo t 1, indicating the possible presence of unique IgE epitopes on the rBlo t 1 molecule. A three-dimensional image of Blo t 1, constructed based on predicted analysis, showed conserved secondary and tertiary structure with other cysteine proteases.

CONCLUSION

We report the cloning, expression and IgE reactivity of Blo t 1, a novel allergen from the domestic mite Blomia tropicalis (Bt), highly homologous to cysteine proteases. This putative cysteine protease, designated Blo t 1, may play a major role as an immunodominant allergen involved in dust mite-specific IgE-mediated hypersensitivity.

Lambda spectra in 11.6A GeV/c Au-Au collisions

E896 has measured Lambda production in 11.6A GeV/c Au-Au collisions over virtually the whole rapidity phase space. The midrapidity p(t) distributions have been measured for the first time at this energy and appear to indicate that the Lambda hyperons have different freeze-out conditions than protons. A comparison with the relativistic quantum molecular dynamics model shows that while there is good shape agreement at high rapidity the model predicts significantly different slopes of the m(t) spectra at midrapidity. The data, where overlap occurs, are consistent with previously reported measurements.