Siglec receptors impact mammalian lifespan by modulating oxidative stress.

Aging is a multifactorial process that includes the lifelong accumulation of molecular damage, leading to age-related frailty, disability and disease, and eventually death. In this study, we report evidence of a significant correlation between the number of genes encoding the immunomodulatory CD33-related sialic acid-binding immunoglobulin-like receptors (CD33rSiglecs) and maximum lifespan in mammals. In keeping with this, we show that mice lacking Siglec-E, the main member of the CD33rSiglec family, exhibit reduced survival. Removal of Siglec-E causes the development of exaggerated signs of aging at the molecular, structural, and cognitive level. We found that accelerated aging was related both to an unbalanced ROS metabolism, and to a secondary impairment in detoxification of reactive molecules, ultimately leading to increased damage to cellular DNA, proteins, and lipids. Taken together, our data suggest that CD33rSiglecs co-evolved in mammals to achieve a better management of oxidative stress during inflammation, which in turn reduces molecular damage and extends lifespan

Appoptosin-Mediated Caspase Cleavage of Tau Contributes to Progressive Supranuclear Palsy Pathogenesis

在该研究中，许教授课题组鉴定了一个在Tau疾病中起关键致病作用的新蛋白Appoptosin。Tau疾病是一类具有共同病理特征：即随着疾病的进程，在脑中会产生Tau蛋白异常聚集和缠结的神经退行性疾病，包括阿尔茨海默症（老年性痴呆）、额颞痴呆、以及进行性核上麻痹（PSP）等。虽然人们推测Tau蛋白异常很可能是导致这些疾病中神经元和脑功能受损的关键因素，但是并不清楚它究竟是如何诱发疾病的。尤其是PSP患者在平衡、眼球运动以及思维上都存在严重的障碍，但迄今为止，人们对该疾病的致病机制几乎一无所知。许教授的研究团队通过对PSP患者的检测，发现一个与该疾病相关的DNA单核苷酸突变（SNP）可以引起Appoptosin蛋白水平的增高，并增加Tau蛋白的过度磷酸化以及caspase-3酶介导的Tau蛋白切割，从而导致Tau蛋白的异常聚集和突触功能障碍。更为重要的是，在阿尔茨海默症和额颞痴呆患者的脑组织中，同样发现了致病蛋白Appoptosin和Tau蛋白异常切割的增加，进一步证明了Appoptosin介导的途径在Tau疾病的发病机制中起到了关键性作用。该研究为进一步阐明神经退行性疾病的病理机制指引了新的研究方向，为痴呆和运动功能障碍的临床治疗提供了全新的治疗靶点和思路，具有重要的临床意义。Progressive supranuclear palsy (PSP) is a movement disorder characterized by tau neuropathology where the underlying mechanism is unknown. An SNP (rs1768208 C/T) has been identified as a strong risk factor for PSP. Here, we identified a much higher T-allele occurrence and increased levels of the pro-apoptotic protein appoptosin in PSP patients. Elevations in appoptosin correlate with activated caspase-3 and caspase-cleaved tau levels. Appoptosin overexpression increased caspase-mediated tau cleavage, tau aggregation, and synaptic dysfunction, whereas appoptosin deficiency reduced tau cleavage and aggregation. Appoptosin transduction impaired multiple motor functions and exacerbated neuropathology in tau-transgenic mice in a manner dependent on caspase-3 and tau. Increased appoptosin and caspase-3-cleaved tau were also observed in brain samples of patients with Alzheimer’s disease and frontotemporal dementia with tau inclusions. Our findings reveal a novel role for appoptosin in neurological disorders with tau neuropathology, linking caspase-3-mediated tau cleavage to synaptic dysfunction and behavioral/motor defects

Correspondence Between Perceived Pubertal Development and Hormone Levels in 9-10 Year-Olds From the Adolescent Brain Cognitive Development Study.

Aim: To examine individual variability between perceived physical features and hormones of pubertal maturation in 9-10-year-old children as a function of sociodemographic characteristics. Methods: Cross-sectional metrics of puberty were utilized from the baseline assessment of the Adolescent Brain Cognitive Development (ABCD) Study—a multi-site sample of 9–10 year-olds (n = 11,875)—and included perceived physical features via the pubertal development scale (PDS) and child salivary hormone levels (dehydroepiandrosterone and testosterone in all, and estradiol in females). Multi-level models examined the relationships among sociodemographic measures, physical features, and hormone levels. A group factor analysis (GFA) was implemented to extract latent variables of pubertal maturation that integrated both measures of perceived physical features and hormone levels. Results: PDS summary scores indicated more males (70%) than females (31%) were prepubertal. Perceived physical features and hormone levels were significantly associated with child\u27s weight status and income, such that more mature scores were observed among children that were overweight/obese or from households with low-income. Results from the GFA identified two latent factors that described individual differences in pubertal maturation among both females and males, with factor 1 driven by higher hormone levels, and factor 2 driven by perceived physical maturation. The correspondence between latent factor 1 scores (hormones) and latent factor 2 scores (perceived physical maturation) revealed synchronous and asynchronous relationships between hormones and concomitant physical features in this large young adolescent sample. Conclusions: Sociodemographic measures were associated with both objective hormone and self-report physical measures of pubertal maturation in a large, diverse sample of 9-10 year-olds. The latent variables of pubertal maturation described a complex interplay between perceived physical changes and hormone levels that hallmark sexual maturation, which future studies can examine in relation to trajectories of brain maturation, risk/resilience to substance use, and other mental health outcomes

Excessive ethanol drinking following a history of dependence: animal model of allostasis. Neuropsychopharmacology 22(6

Excessive drinking of ethanol in animals can be produced by a number of factors including altering palatability, genetics, and history of consumption. There is evidence that certain symptoms of withdrawal can persist for a number of weeks or even months following chronic ethanol exposure in humans In a larger cohort of 312 abstinent alcoholics, 20-25% of them showed signs of anxiety and depression, as determined from the Symptom Check-List 90 (self-report inventory with coverage of areas of symptomology and psychopathology) six months to two years following withdrawal Potential rodent models of excessive ethanol drinking include the alcohol deprivation effect in nondependent animals, ethanol self-administration in dependent withdrawing animals, and ethanol self-administration in animals with a history of dependence following periods of abstinence. The alcohol deprivation effect is a transient increase in ethanol self-administration in animals following periods of abstinence from ethanol for several days to several weeks Animal studies directed at examining the effects of withdrawal on ethanol self-administration have produced varying results Allostasis is a form of physiological regulation first hypothesized to describe the fluctuations in blood pressure and immune system function that are not well explained by homeostasis The persistent affective withdrawal symptoms observed in human alcoholics also may be a reflection of a shift in reward set point such that reward system functioning is decreased below baseline in the drug-free state. It has been argued that global allostatic changes associated with chronic demands lead to an unpleasant withdrawal state when the demands are lifted and provides the basis for seeking conditions of high demand The purpose of the current experiments was to examine potential alterations in operant oral ethanol selfadministration following protracted abstinence in rats with a history of dependence. Based on the conceptualization of ethanol addiction as reflecting an enhancement in drug reward set point or threshold (Koob and Le Moal 1997), it was hypothesized that rats with a history of dependence would show a long lasting increase in baseline ethanol responding. Therefore, the model described herein has the potential to provide a means to examine long lasting alterations in the mechanisms mediating ethanol reward which may be partly responsible for the chronically relapsing nature of alcoholism in humans. A paradigm was used in which rats were first trained to lever press for ethanol and then made dependent on ethanol in vapor chambers MATERIALS AND METHODS General Methods Animals. Male Wistar rats obtained from Charles River Laboratory (Kingston, NY) were used in Experiments 1-3 ( n ϭ 48), whereas Wistar rats originally derived from Charles River Laboratory (Kingston, NY), but bred in the Beckman Laboratories of The Scripps Research Institute, were used in Experiment 4 ( n ϭ 12). These latter Wistar rats are bred using a circular-pair random system of breeding in order to maintain genetic heterogeneity and new breeders are obtained from Charles River as determined by our internal Genetics Advisory Board. Separate groups of rats were used for each of the four experiments. Body weight was 180-200 g at the start of the experiments. Rats were housed 2-3 per cage with food and water available ad libitum , except for three days of water restriction at the initiation of operant testing (see below). Lights were on a 12-hr light/dark cycle, with lights on at 6:00 AM. All procedures met the guidelines of the National Institutes of Health Guide for the Care and Use of Laboratory Animals. Operant Ethanol Self-Administration. Ethanol dilutions (5, 8, and 10% w/v) were prepared with 95% ethyl alcohol and water. Saccharin (Sigma Chemical Co., St. Louis, MO) was added to water or the ethanol solutions to achieve a concentration of 0.2% w/v. Standard operant chambers (Coulbourn Instruments, Allentown, PA) housed in sound-attenuated, ventilated cubicles were used for ethanol self-administration. Syringe pumps dispensed ethanol and water into two stainless steel drinking cups mounted 4 cm above the grid floor in the middle of one side panel. Two retractable levers were located 4.5 cm to either side of the drinking cups. Fluid delivery and recording of operant responding were controlled by microcomputer. A continuous reinforcement (FR1) schedule was used, and responding resulted in delivery of 0.1 ml of fluid. During the 0.5 second in which the pumps are activated, lever presses are not recorded. Rats were trained to lever press for ethanol using an adaptation of Samson's sweetened solution fading procedure Operant sessions were 30 minutes during the training phase and were conducted five days per week between 9:00 AM and 12:00 PM. Extended operant self-administration test sessions (12 hr) were conducted in Experiments 1 and 2. These were initiated at 6:00 PM, the beginning of the rats' active phase (dark cycle). Food was 584 A.J. Roberts et al. N EUROPSYCHOPHARMACOLOGY 2000 -VOL . 22 , NO . 6 placed in each operant box and 10% ethanol and water were available contingent on lever pressing. Test sessions in Experiments 3 and 4 were conducted in a manner similar to those used during training (30 min). Ethanol Vapor Chamber Procedure. Ethanol vapor exposure is a reliable technique for inducing ethanol dependence in that blood alcohol levels can be tightly controlled and animals are free-moving and gain weight normally Target blood alcohol levels were 150-200 mg% across the 2-4 week exposure time. This paradigm has been shown to produce physical dependence as evidenced by the appearance of observable withdrawal symptoms upon removal from the chambers Experiment 1 The purpose of this experiment was to determine whether increased responding for ethanol persisted beyond the acute withdrawal phase. It was shown previously that rats trained to lever press for ethanol and then exposed to ethanol vapor for two weeks, selfadministered more ethanol in operant boxes than control rats exposed to air across an entire 12-hr withdrawal test session Eight rats were trained to lever press for 10% ethanol and exposed to ethanol vapor ( n ϭ 4) or control air ( n ϭ 4). Groups were matched based on the final three days of 30-min operant testing. Following two weeks of vapor exposure, all rats were removed and placed immediately in operant boxes for a 12-hr overnight (active phase of circadian cycle) ethanol self-administration session. The rats were then re-exposed to the vapor chambers for five days and retested in a second 12-hr overnight session. Following this test, the rats were left out of the vapor chambers and not disturbed, except for routine husbandry, for two weeks. At this time, another 12-hr operant ethanol self-administration session was conducted. The rats were retested in this manner at 4 and 8 weeks following removal from the vapor chambers with no exposure to the operant boxes between these retest sessions (see Experiment 2 The purpose of Experiment 2 was to determine whether prior exposure to ethanol vapor would lead to in- Ethanol Self-Administration in Protracted Abstinence 585 creased ethanol self-administration even if the rats were not tested previously during early withdrawal. In this case, rats would be tested in the absence of potential learned associations between lever pressing for ethanol and relief from early withdrawal symptoms. Again, the hypothesis was that rats previously exposed to ethanol vapor should have greater motivation to lever press for ethanol following protracted withdrawal. Twenty eight rats were trained to lever press for 10% ethanol. On the final day of training, a 12-hr overnight test in the operant boxes was conducted in order to control for the extra test given to the rats during withdrawal in Experiment 1, as well as to select groups showing indistinguishable patterns of responding. The rats were then exposed for two weeks to ethanol vapor ( n ϭ 13) or control air ( n ϭ 15). One rat in the ethanol vapor group was lost due to over-intoxication (BAL Ͼ 300 mg%). Following removal from the vapor chambers, the rats were not disturbed for two weeks at which time they were tested in a second 12-hr overnight session in the operant self-administration boxes. This was repeated four and eight weeks following removal from the vapor chambers (see Experiment 3 The purpose of this experiment was to examine the effect of prior exposure to chronic ethanol vapor and subsequent abstinence on the resumption of daily 30-min test sessions. The results of Experiment 2 suggested that the only difference between the groups following protracted abstinence (when rats were not tested during early withdrawal) was in the first hour of retests. Therefore, the purpose of this experiment was to examine the effects of chronic ethanol exposure and a two week period of abstinence on the alcohol deprivation effect and its recovery to stable baseline responding. In addition, these rats were scored for ethanol withdrawal severity in order to confirm that the ethanol vapor chamber protocol was producing physical dependence as had been found previously Twelve rats were trained to lever press for 10% ethanol and then half were exposed to ethanol vapor ( n ϭ 6) and half were exposed to air ( n ϭ 6) for two weeks. Eight hours following removal from the chambers, the rats were tested for ethanol withdrawal symptoms. Rats were scored from 0 (undetectable) to 2 (severe) in a test of ventromedial distal limb flexion and observed for tail stiffness and abnormal body posture. The sum of these three measures represented overall withdrawal severity, yielding a range from 0 to 6. More detail regarding this procedure has been previously published Experiment 4 The results of the previous experiments showed that there appears to be an enhancement of the alcohol deprivation effect and an increase to a new higher baseline of responding for ethanol in rats previously exposed to ethanol vapor, relatively to air exposed rats. Thus, the purpose of Experiment 4 was to further investigate this finding by allowing rats three cycles of abstinence and retesting following a single ethanol vapor exposure. In this experiment, rats were exposed to ethanol vapor or air for one month. Again, it was hypothesized that rats previously exposed to ethanol vapor would show enhanced alcohol deprivation effects and higher baseline levels of responding over several repeated tests. Twelve rats were trained to lever press for 10% ethanol and then half were exposed to ethanol vapor ( n ϭ 6), whereas the other half was exposed to air ( n ϭ 6) for four weeks. Following removal from the chambers, the rats were left undisturbed for two weeks and then daily 30-min operant ethanol self-administration sessions were resumed for seven days. Rats were deprived of ethanol (not exposed to operant self-administration boxes) for three 1-week intervals separated by seven daily 30-min operant sessions in which 10% ethanol and water were available (see Data Analysis Operant responding was analyzed by mixed factor 2-way analysis of variance. The between-subject factor was group (ethanol vapor versus air control) and the within-subject factor was time (hours in Experiments 1 and 2 and repeated daily sessions in Experiments 3 and 4). Each cycle of retest was analyzed separately. Interactions between group and either hour or session were investigated using simple main effects analyses. RESULTS Operant responding for ethanol by rats in the present experiments was similar to that found in previous experiments in which blood alcohol levels were determined. For example, at the completion of a 12-hr early withdrawal test session, similar to that used in Experiment 1, rats were found to have blood alcohol levels of approximately 100 mg% N EUROPSYCHOPHARMACOLOGY 2000 -VOL . 22 , NO . 6 have been associated with blood alcohol levels of 40-80 mg% Experiment 1 Baseline responding for ethanol was 21.1 Ϯ 2.4 responses in the final 30-min training session prior to ethanol vapor exposure. Blood alcohol levels achieved by rats in the ethanol vapor chambers averaged 157 Ϯ 19 mg% across the two weeks of exposure (time course data not shown). Body weights upon removal from the vapor chambers were 454 Ϯ 51 g in the ethanol vapor group and 436 Ϯ 21 g in the air control group. The results of this experiment are shown in These results suggest that the enhancement in operant responding for ethanol by rats exposed to chronic ethanol vapor which accompanies acute withdrawal is maintained over several weeks of protracted abstinence. Experiment 2 Baseline responding for ethanol was 27.2 Ϯ 3.8 responses in the final 30-min training session prior to ethanol vapor exposure. Blood alcohol levels of ethanol vapor-exposed rats averaged 149 Ϯ 15 mg%. Body weights upon removal from the vapor chambers were 483 Ϯ 20 g in the ethanol vapor group and 486 Ϯ 18 g in the air control group. The results of Experiment 2 are shown in Experiment 3 Baseline responding for ethanol was 26.3 Ϯ 3.7 responses in the final 30-min training session prior to ethanol vapor exposure. Blood alcohol levels averaged 150 Ϯ 6 mg% across the two weeks of ethanol vapor exposure. Body weights upon removal from the vapor chambers were 492 Ϯ 21 g in the ethanol vapor group and 481 Ϯ 16 g in the air control group. Withdrawal scores in ethanol vapor-treated rats averaged 3.9 Ϯ 0.4 and in air controls were 0.57 Ϯ 0.2. The scores of the ethanol vapor group are consistent with previous results The results of Experiment 3 are shown in NEUROPSYCHOPHARMACOLOGY 2000-VOL. 22, NO. 6 the first retest session as indicated by a significant main effect of group (F[1,12] ϭ 11.7, p Ͻ .01) and a significant group by time epoch interaction (F[5,60] Experiment 4 Baseline responding for ethanol was 19.2 Ϯ 3.1 responses in the final 30-min training session prior to ethanol vapor exposure. Blood alcohol levels of ethanol vapor rats averaged 143 Ϯ 15 mg% for the one-month NEUROPSYCHOPHARMACOLOGY 2000-VOL. 22, NO. 6 Ethanol Self-Administration in Protracted Abstinence 589 exposure time. Body weights upon removal from the vapor chambers were 506 Ϯ 17 g in the ethanol vapor group and 522 Ϯ 16 g in the air control group. The results of this experiment are shown in NEUROPSYCHOPHARMACOLOGY 2000-VOL. 22, NO. 6 ses revealing significant effects of group in the first three test sessions of the blocks (F[1,18] ϭ 8.6-9.1, p Ͻ .01). The results of Experiment 4 are in accordance with those of the previous three experiments in that prior exposure to chronic ethanol vapor is associated with an increase in operant ethanol self-administration. As in Experiment 2, when rats were not tested during withdrawal, this effect appeared to be statistically reliable through the 4th or 5th week following removal from the vapor chambers. DISCUSSION The principal result of these experiments was that rats with a history of chronic ethanol exposure, sufficient to produce signs of physical dependence, showed persistent increases in operant ethanol self-administration during withdrawal and protracted abstinence. This is an important finding as it suggests that increases in ethanol self-administration can persist for 4-8 weeks fol- NEUROPSYCHOPHARMACOLOGY 2000-VOL. 22, NO. 6 Ethanol Self-Administration in Protracted Abstinence 591 lowing a single chronic ethanol exposure sufficient to produce dependence. The increase was anywhere from 30% to 100% above baseline, and, based on previous data would result in an increase in blood alcohol levels from about 25-30 mg% to 40-80 mg% in 30-min sessions The differences between the findings of Experiments 1 and 2 are quite intriguing and suggest that experience with ethanol self-administration during the early withdrawal period leads to a more robust increase in ethanol self-administration under conditions of protracted abstinence. This may be due to the development of an association between ethanol drinking and alleviation of withdrawal signs which enhances the reinforcing efficacy of ethanol. If animals are allowed to self-administer ethanol during repeated withdrawals, they show more robust increases in preference for ethanol 592 A.J. Roberts et al

Transplantation of wild-type mouse hematopoietic stem and progenitor cells ameliorates deficits in a mouse model of Friedreich's ataxia.

Friedreich's ataxia (FRDA) is an incurable autosomal recessive neurodegenerative disease caused by reduced expression of the mitochondrial protein frataxin due to an intronic GAA-repeat expansion in the FXN gene. We report the therapeutic efficacy of transplanting wild-type mouse hematopoietic stem and progenitor cells (HSPCs) into the YG8R mouse model of FRDA. In the HSPC-transplanted YG8R mice, development of muscle weakness and locomotor deficits was abrogated as was degeneration of large sensory neurons in the dorsal root ganglia (DRGs) and mitochondrial capacity was improved in brain, skeletal muscle, and heart. Transplanted HSPCs engrafted and then differentiated into microglia in the brain and spinal cord and into macrophages in the DRGs, heart, and muscle of YG8R FRDA mice. We observed the transfer of wild-type frataxin and Cox8 mitochondrial proteins from HSPC-derived microglia/macrophages to FRDA mouse neurons and muscle myocytes in vivo. Our results show the HSPC-mediated phenotypic rescue of FRDA in YG8R mice and suggest that this approach should be investigated further as a strategy for treating FRDA

A description of the ABCD organizational structure and communication framework

The Adolescent Brain Cognitive Development (ABCD) study is designed to be the largest study of brain development and child health in the United States, performing comprehensive assessments of 11,500 children repeatedly for 10 years. An endeavor of this magnitude requires an organized framework of governance and communication that promotes collaborative decision-making and dissemination of information. The ABCD consortium structure, built upon the Matrix Management approach of organizational theory, facilitates the integration of input from all institutions, numerous internal workgroups and committees, federal partners, and external advisory groups to make use of a broad range of expertise to ensure the study’s success. Keywords: Adolescence, Development, Neuroimaging, Longitudinal, Organizational framework, Governanc

A description of the ABCD organizational structure and communication framework.

The Adolescent Brain Cognitive Development (ABCD) study is designed to be the largest study of brain development and child health in the United States, performing comprehensive assessments of 11,500 children repeatedly for 10 years. An endeavor of this magnitude requires an organized framework of governance and communication that promotes collaborative decision-making and dissemination of information. The ABCD consortium structure, built upon the Matrix Management approach of organizational theory, facilitates the integration of input from all institutions, numerous internal workgroups and committees, federal partners, and external advisory groups to make use of a broad range of expertise to ensure the study's success

Biospecimens and the ABCD study: Rationale, methods of collection, measurement and early data.

Biospecimen collection in the Adolescent Brain Cognitive Development (ABCD) study - of hair samples, shed deciduous (baby) teeth, and body fluids - will serve dual functions of screening for study eligibility, and providing measures of biological processes thought to predict or correlate with key study outcomes on brain and cognitive development. Biosamples are being collected annually to screen for recency of drug use prior to the neuroimaging or cognitive testing visit, and to store for the following future studies: (1) on the effects of exposure to illicit and recreational drugs (including alcohol and nicotine); (2) of pubertal hormones on brain and cognitive developmental trajectories; (3) on the contribution of genomics and epigenomics to child and adolescent development and behavioral outcomes; and (4) with pre- and post-natal exposure to environmental neurotoxicants and drugs of abuse measured from novel tooth analyses. The present manuscript describes the rationales for inclusion and selection of the specific biospecimens, methodological considerations for each measure, future plans for assessment of biospecimens during follow-up visits, and preliminary ABCD data to illustrate methodological considerations