Commentary: Global Alzheimer's disease and Alzheimer's disease related dementia research funding organizations support and engage the research community throughout the COVID-19 pandemic.

The COVID-19 pandemic has disproportionately affected more vulnerable populations, including those living with dementia. Over 50 million individuals worldwide are living with Alzheimer's disease (AD) or other dementia, and it is crucial to continue the fight against the condition during the global pandemic. Since the start of mandated lockdowns in March 2020, charity and non-profit organizations that fund AD and related dementia research continue to respond to the needs of the AD research community, ensuring the momentum continues and accelerates. Members of the International Alzheimer's and Related Dementia Research Funder Consortium, a group of nearly 40 funding organizations that informally convene throughout the year to share updates and information, have taken a number of steps to ensure the continued support of the research community. Even during times of uncertainty, it is essential that the field moves forward to uncover preventions, diagnoses, and treatments for these diseases that affect many millions globally.

Benfotiamine treatment activates the Nrf2/ARE pathway and is neuroprotective in a transgenic mouse model of tauopathy.

Impaired glucose metabolism, decreased levels of thiamine and its phosphate esters, and reduced activity of thiamine-dependent enzymes, such as pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase and transketolase occur in Alzheimer's disease (AD). Thiamine deficiency exacerbates amyloid beta (Aß) deposition, tau hyperphosphorylation and oxidative stress. Benfotiamine (BFT) rescued cognitive deficits and reduced Aß burden in amyloid precursor protein (APP)/PS1 mice. In this study, we examined whether BFT confers neuroprotection against tau phosphorylation and the generation of neurofibrillary tangles (NFTs) in the P301S mouse model of tauopathy. Chronic dietary treatment with BFT increased lifespan, improved behavior, reduced glycated tau, decreased NFTs and prevented death of motor neurons. BFT administration significantly ameliorated mitochondrial dysfunction and attenuated oxidative damage and inflammation. We found that BFT and its metabolites (but not thiamine) trigger the expression of Nrf2/antioxidant response element (ARE)-dependent genes in mouse brain as well as in wild-type but not Nrf2-deficient fibroblasts. Active metabolites were more potent in activating the Nrf2 target genes than the parent molecule BFT. Docking studies showed that BFT and its metabolites (but not thiamine) bind to Keap1 with high affinity. These findings demonstrate that BFT activates the Nrf2/ARE pathway and is a promising therapeutic agent for the treatment of diseases with tau pathology, such as AD, frontotemporal dementia and progressive supranuclear palsy.

Loss of spatacsin function alters lysosomal lipid clearance leading to upper and lower motor neuron degeneration.

Mutations in SPG11 account for the most common form of autosomal recessive hereditary spastic paraplegia (HSP), characterized by a gait disorder associated with various brain alterations. Mutations in the same gene are also responsible for rare forms of Charcot-Marie-Tooth (CMT) disease and progressive juvenile-onset amyotrophic lateral sclerosis (ALS). To elucidate the physiopathological mechanisms underlying these human pathologies, we disrupted the Spg11 gene in mice by inserting stop codons in exon 32, mimicking the most frequent mutations found in patients. The Spg11 knockout mouse developed early-onset motor impairment and cognitive deficits. These behavioral deficits were associated with progressive brain atrophy with the loss of neurons in the primary motor cortex, cerebellum and hippocampus, as well as with accumulation of dystrophic axons in the corticospinal tract. Spinal motor neurons also degenerated and this was accompanied by fragmentation of neuromuscular junctions and muscle atrophy. This new Spg11 knockout mouse therefore recapitulates the full range of symptoms associated with SPG11 mutations observed in HSP, ALS and CMT patients. Examination of the cellular alterations observed in this model suggests that the loss of spatacsin leads to the accumulation of lipids in lysosomes by perturbing their clearance from these organelles. Altogether, our results link lysosomal dysfunction and lipid metabolism to neurodegeneration and pinpoint a critical role of spatacsin in lipid turnover.

Methylene blue upregulates Nrf2/ARE genes and prevents tau-related neurotoxicity.

Methylene blue (MB, methylthioninium chloride) is a phenothiazine that crosses the blood brain barrier and acts as a redox cycler. Among its beneficial properties are its abilities to act as an antioxidant, to reduce tau protein aggregation and to improve energy metabolism. These actions are of particular interest for the treatment of neurodegenerative diseases with tau protein aggregates known as tauopathies. The present study examined the effects of MB in the P301S mouse model of tauopathy. Both 4 mg/kg MB (low dose) and 40 mg/kg MB (high dose) were administered in the diet ad libitum from 1 to 10 months of age. We assessed behavior, tau pathology, oxidative damage, inflammation and numbers of mitochondria. MB improved the behavioral abnormalities and reduced tau pathology, inflammation and oxidative damage in the P301S mice. These beneficial effects were associated with increased expression of genes regulated by NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE), which play an important role in antioxidant defenses, preventing protein aggregation, and reducing inflammation. The activation of Nrf2/ARE genes is neuroprotective in other transgenic mouse models of neurodegenerative diseases and it appears to be an important mediator of the neuroprotective effects of MB in P301S mice. Moreover, we used Nrf2 knock out fibroblasts to show that the upregulation of Nrf2/ARE genes by MB is Nrf2 dependent and not due to secondary effects of the compound. These findings provide further evidence that MB has important neuroprotective effects that may be beneficial in the treatment of human neurodegenerative diseases with tau pathology.

["Evoking intellectual autonomy means addressing the relationship between people"]. / « Évoquer l'autonomie intellectuelle, c'est aborder la relation entre les gens ¼.

The intellectual autonomy of elderly people must be preserved. This concerns all their senses and more widely the feeling of being alive and being connected to others. Elderly people must have control over their own lives up until the end and we must open ourselves up and accept them in their entirety. Paulette Guinchard-Kunstler has worked at the highest level to raise awareness of this issue. An interview with a woman with strong convictions.

PGC-1α overexpression exacerbates ß-amyloid and tau deposition in a transgenic mouse model of Alzheimer's disease.

The peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) interacts with various transcription factors involved in energy metabolism and in the regulation of mitochondrial biogenesis. PGC-1α mRNA levels are reduced in a number of neurodegenerative diseases and contribute to disease pathogenesis, since increased levels ameliorate behavioral defects and neuropathology of Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. PGC-1α and its downstream targets are reduced both in postmortem brain tissue of patients with Alzheimer's disease (AD) and in transgenic mouse models of AD. Therefore, we investigated whether increased expression of PGC-1α would exert beneficial effects in the Tg19959 transgenic mouse model of AD; Tg19959 mice express the human amyloid precursor gene (APP) with 2 familial AD mutations and develop increased ß-amyloid levels, plaque deposition, and memory deficits by 2-3 mo of age. Rather than an improvement, the cross of the Tg19959 mice with mice overexpressing human PGC-1α exacerbated amyloid and tau accumulation. This was accompanied by an impairment of proteasome activity. PGC-1α overexpression induced mitochondrial abnormalities, neuronal cell death, and an exacerbation of behavioral hyperactivity in the Tg19959 mice. These findings show that PGC-1α overexpression exacerbates the neuropathological and behavioral deficits that occur in transgenic mice with mutations in APP that are associated with human AD.

Bezafibrate administration improves behavioral deficits and tau pathology in P301S mice.

Peroxisome proliferator-activated receptors (PPARs) are ligand-mediated transcription factors, which control both lipid and energy metabolism and inflammation pathways. PPARγ agonists are effective in the treatment of metabolic diseases and, more recently, neurodegenerative diseases, in which they show promising neuroprotective effects. We studied the effects of the pan-PPAR agonist bezafibrate on tau pathology, inflammation, lipid metabolism and behavior in transgenic mice with the P301S human tau mutation, which causes familial frontotemporal lobar degeneration. Bezafibrate treatment significantly decreased tau hyperphosphorylation using AT8 staining and the number of MC1-positive neurons. Bezafibrate treatment also diminished microglial activation and expression of both inducible nitric oxide synthase and cyclooxygenase 2. Additionally, the drug differentially affected the brain and brown fat lipidome of control and P301S mice, preventing lipid vacuoles in brown fat. These effects were associated with behavioral improvement, as evidenced by reduced hyperactivity and disinhibition in the P301S mice. Bezafibrate therefore exerts neuroprotective effects in a mouse model of tauopathy, as shown by decreased tau pathology and behavioral improvement. Since bezafibrate was given to the mice before tau pathology had developed, our data suggest that bezafibrate exerts a preventive effect on both tau pathology and its behavioral consequences. Bezafibrate is therefore a promising agent for the treatment of neurodegenerative diseases associated with tau pathology.

Pioglitazone halts axonal degeneration in a mouse model of X-linked adrenoleukodystrophy.

X-linked adrenoleukodystrophy is a neurometabolic disorder caused by inactivation of the peroxisomal ABCD1 transporter of very long-chain fatty acids. In mice, ABCD1 loss causes late onset axonal degeneration in the spinal cord in association with locomotor disability resembling the most common phenotype in patients, adrenomyeloneuropathy. Increasing evidence indicates that oxidative stress and bioenergetic failure play major roles in the pathogenesis of X-linked adrenoleukodystrophy. In this study, we aimed to evaluate whether mitochondrial biogenesis is affected in X-linked adrenoleukodystrophy. We demonstrated that Abcd1 null mice show reduced mitochondrial DNA concomitant with downregulation of mitochondrial biogenesis pathway driven by PGC-1α/PPARγ and reduced expression of mitochondrial proteins cytochrome c, NDUFB8 and VDAC. Moreover, we show that the oral administration of pioglitazone, an agonist of PPARγ, restored mitochondrial content and expression of master regulators of biogenesis, neutralized oxidative damage to proteins and DNA, and reversed bioenergetic failure in terms of ATP levels, NAD+/NADH ratios, pyruvate kinase and glutathione reductase activities. Most importantly, the treatment halted locomotor disability and axonal damage in X-linked adrenoleukodystrophy mice. These results lend support to the use of pioglitazone in clinical trials with patients with adrenomyeloneuropathy and reveal novel molecular mechanisms of action of pioglitazone in neurodegeneration. Future studies should address the effects of this anti-diabetic drug on other axonopathies in which oxidative stress and mitochondrial dysfunction are contributing factors.

[The development and benefits of working together in geriatric short stay units]. / Mise en place et bénéfices du binôme en court séjour gériatrique.

Ambroise-Paré hospital (AP-HP, 92) set up a new work organisation based on the nurse/nursing auxiliary partnership in the geriatric short stay unit in response to the wishes of the healthcare manager and nursing team. It was introduced over three months and in several stages in order to limit sticking points and support the team in its new practice.

C9ORF72 knockdown triggers FTD-like symptoms and cell pathology in mice.

The GGGGCC intronic repeat expansion within C9ORF72 is the most common genetic cause of ALS and FTD. This mutation results in toxic gain of function through accumulation of expanded RNA foci and aggregation of abnormally translated dipeptide repeat proteins, as well as loss of function due to impaired transcription of C9ORF72. A number of in vivo and in vitro models of gain and loss of function effects have suggested that both mechanisms synergize to cause the disease. However, the contribution of the loss of function mechanism remains poorly understood. We have generated C9ORF72 knockdown mice to mimic C9-FTD/ALS patients haploinsufficiency and investigate the role of this loss of function in the pathogenesis. We found that decreasing C9ORF72 leads to anomalies of the autophagy/lysosomal pathway, cytoplasmic accumulation of TDP-43 and decreased synaptic density in the cortex. Knockdown mice also developed FTD-like behavioral deficits and mild motor phenotypes at a later stage. These findings show that C9ORF72 partial loss of function contributes to the damaging events leading to C9-FTD/ALS.

In vivo pathogenic role of mutant SOD1 localized in the mitochondrial intermembrane space.

Mutations in Cu,Zn superoxide dismutase (SOD1) are associated with familial amyotrophic lateral sclerosis (ALS). Mutant SOD1 causes a complex array of pathological events, through toxic gain of function mechanisms, leading to selective motor neuron degeneration. Mitochondrial dysfunction is among the well established toxic effects of mutant SOD1, but its mechanisms are just starting to be elucidated. A portion of mutant SOD1 is localized in mitochondria, where it accumulates mostly on the outer membrane and inside the intermembrane space (IMS). Evidence in cultured cells suggests that mutant SOD1 in the IMS causes mitochondrial dysfunction and compromises cell viability. Therefore, to test its pathogenic role in vivo we generated transgenic mice expressing G93A mutant or wild-type (WT) human SOD1 targeted selectively to the mitochondrial IMS (mito-SOD1). We show that mito-SOD1 is correctly localized in the IMS, where it oligomerizes and acquires enzymatic activity. Mito-G93ASOD1 mice, but not mito-WTSOD1 mice, develop a progressive disease characterized by body weight loss, muscle weakness, brain atrophy, and motor impairment, which is more severe in females. These symptoms are associated with reduced spinal motor neuron counts and impaired mitochondrial bioenergetics, characterized by decreased cytochrome oxidase activity and defective calcium handling. However, there is no evidence of muscle denervation, a cardinal pathological feature of ALS. Together, our findings indicate that mutant SOD1 in the mitochondrial IMS causes mitochondrial dysfunction and neurodegeneration, but per se it is not sufficient to cause a full-fledged ALS phenotype, which requires the participation of mutant SOD1 localized in other cellular compartments.

Behavioral deficit, oxidative stress, and mitochondrial dysfunction precede tau pathology in P301S transgenic mice.

Abnormal tau accumulation can lead to the development of neurodegenerative diseases. P301S mice overexpress the human tau mutated gene, resulting in tau hyperphosphorylation and tangle formation. Mice also develop synaptic deficits and microglial activation prior to any neurodegeneration and tangles. Oxidative stress can also affect tauopathy. We studied the role of oxidative stress in relationship to behavioral abnormalities and disease progression in P301S mice at 2, 7, and 10 mo of age. At 7 mo of age, P301S mice had behavioral abnormalities, such as hyperactivity and disinhibition. At the same age, we observed increased carbonyls in P301S mitochondria (∼215 and 55% increase, males/females), and deregulation in the activity and content of mitochondrial enzymes involved in reactive oxygen species formation and energy metabolism, such as citrate synthase (∼19 and ∼5% decrease, males/females), MnSOD (∼16% decrease, males only), cytochrome C (∼19% decrease, females only), and cytochrome C oxidase (∼20% increase, females only). These changes in mitochondria proteome appeared before tau hyperphosphorylation and tangle formation, which were observed at 10 mo and were associated with GSK3ß activation. At that age, mitochondria proteome deregulation became more apparent in male P301S mitochondria. The data strongly suggest that oxidative stress and mitochondrial abnormalities appear prior to tau pathology.

[Implementation of a procedure for nominating a health care surrogate]. / Mise en oeuvre d'une procédure de désignation d'une personne de confiance.

A procedure for the systematic nomination of a health care surrogate was put in place following a multi-disciplinary approach within an acute care geriatric unit at Ambroise-Paré hospital in Boulogne-Billancourt. Its originality lies in the way the whole team, on the initiative of a doctor, prepared the procedure, implemented it and assessed it. A review.

Effects of synaptic modulation on beta-amyloid, synaptophysin, and memory performance in Alzheimer's disease transgenic mice.

Accumulation of ß-amyloid (Aß) and loss of synapses are hallmarks of Alzheimer's disease (AD). How synaptic activity relates to Aß accumulation and loss of synapses is a current topic of major interest. Synaptic activation promotes Aß secretion, and chronic reduction of synaptic activity reduced Aß plaques in an AD transgenic mouse model. This suggested beneficial effects of reducing synaptic activity in AD. We now show that reduced synaptic activity causes detrimental effects on synapses and memory despite reducing plaques using two different models of chronic synaptic inhibition: deafferentation of the barrel cortex and administration of benzodiazepine. An interval of prolonged synaptic inhibition exacerbated loss of synaptophysin compared with synaptically more active brain in AD transgenic but not wild-type mice. Furthermore, an interval of benzodiazepine treatment, followed by a washout period, exacerbated memory impairment in AD transgenic mice. Exacerbation of synaptic and behavioral abnormalities occurred in the setting of reduced Aß plaques but elevated intraneuronal Aß immunoreactivity. These data support beneficial effects of synaptic activation on Aß-related synaptic and behavioral impairment in AD.

Behavioral deficits and progressive neuropathology in progranulin-deficient mice: a mouse model of frontotemporal dementia.

Progranulin haploinsufficiency causes frontotemporal dementia with tau-negative, ubiquitin-positive neuronal inclusion pathology. In this study, we showed that progranulin-deficient mice displayed increased depression- and disinhibition-like behavior, as well as deficits in social recognition from a relatively young age. These mice did not have any deficit in locomotion or exploration. Eighteen-month-old progranulin-deficient mice demonstrated impaired spatial learning and memory in the Morris water maze. In addition to behavioral deficits, progranulin-deficient mice showed a progressive development of neuropathology from 12 mo of age, including enhanced activation of microglia and astrocytes and ubiquitination and cytoplasmic accumulation of phosphorylated TDP-43. Thus, progranulin deficiency induced FTD-like behavioral and neuropathological deficits. These mice may serve as an important tool for deciphering underlying mechanisms in frontotemporal dementia.

CORE management: The reality principle.

Responsible science is mandatory for every research institution. As economic challenges, fast evolving technologies and competitiveness impact drastically the scientific productivity and quality, institutions must take action. Research core facilities using animal models (CORE) are central in biomedical institutions. Therefore, building a strong CORE represents a priority for research organizations. More precisely, COREs must define their purpose, ensure proper long term resources and promote ethics and transparency. The heads of COREs play, as managers, a key role in the development and in the coordination of all activities. They deal with multiple challenges, such as divergent objectives, heavy workload and limited resources, exposing them to psychosocial risks, and might compromise their ability to react rationally to the pressure. The implementation of a culture of care and of social responsibility is essential for COREs and for their institutions. In this, the collaborative efforts between institutions' officials, administrative staff and scientists allow the support of CORE decisions, the development of innovative tools and the promotion of a responsible science. Overall, the improvement of the CORE strategy and functioning results in increased scientific success rates for the institution, while reducing psychosocial risks for personnel.

Synaptic activity reduces intraneuronal Abeta, promotes APP transport to synapses, and protects against Abeta-related synaptic alterations.

A central question in Alzheimer's disease research is what role synaptic activity plays in the disease process. Synaptic activity has been shown to induce beta-amyloid peptide release into the extracellular space, and extracellular beta-amyloid has been shown to be toxic to synapses. We now provide evidence that the well established synaptotoxicity of extracellular beta-amyloid requires gamma-secretase processing of amyloid precursor protein. Recent evidence supports an important role for intraneuronal beta-amyloid in the pathogenesis of Alzheimer's disease. We show that synaptic activity reduces intraneuronal beta-amyloid and protects against beta-amyloid-related synaptic alterations. We demonstrate that synaptic activity promotes the transport of the amyloid precursor protein to synapses using live cell imaging, and that the protease neprilysin is involved in reduction of intraneuronal beta-amyloid with synaptic activity.