Impact of Alzheimer's association support and engagement in the AD/ADRD research community through the COVID-19 pandemic and beyond.

INTRODUCTION: The WHO estimates that 55 million people worldwide have dementia and this number is expected to increase to 139 million by 2050. Founded in 1980, the Alzheimer's Association is the world's leading voluntary health organization in AD/ADRD care, support and research. METHODS: Alzheimer's Association-led funding opportunities and awards, conferences and other activities beginning with the COVID-19 pandemic were reviewed. RESULTS: The Association remains committed to funding, convening, leading and implementing research studies that accelerate the global effort to eliminate Alzheimer's and all other dementia. DISCUSSION: This manuscript describes funding, convening and other global initiatives, influenced in part by the COVID-19 pandemic, to strengthen and drive research forward.

Sensitivity of the U.S. Wheat Powdery Mildew Population to Quinone Outside Inhibitor Fungicides and Determination of the Complete Blumeria graminis f. sp. tritici Cytochrome b Gene.

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is managed primarily with cultivar resistance and foliar fungicides. Quinone outside inhibitors (QoIs), which target the mitochondrial cytochrome b (cytb) gene, are one of the two main fungicide classes used on wheat. While European populations of B. graminis f. sp. tritici are widely insensitive to QoIs, largely because of the cytb mutation G143A, the QoI sensitivity of the U.S. B. graminis f. sp. tritici population had never been evaluated despite years of QoI use on U.S. wheat. A total of 381 B. graminis f. sp. tritici isolates from 15 central and eastern U.S. states were screened for sensitivity to QoI fungicides pyraclostrobin and picoxystrobin. A modest range of sensitivities was observed, with maximum resistance factors of 11.2 for pyraclostrobin and 5.3 for picoxystrobin. The F129L, G137R, and G143A cytb mutations were not detected in the U.S. B. graminis f. sp. tritici population, nor were mutations identified in the PEWY loop, a key part of the Qo site. Thus, no genetic basis for the observed quantitative variation in QoI sensitivity of U.S. B. graminis f. sp. tritici was identified. Isolate sporulation was weakly negatively associated with reduced QoI sensitivity, suggesting a fitness cost. In the course of the study, the complete B. graminis f. sp. tritici cytb gene sequence was determined for the first time in the isolate 96224 v. 3.16 reference genome. Contrary to previous reports, the gene has an intron that appears to belong to intron group II, which is unusual in fungi. The study was the first QoI sensitivity screening of a large, geographically diverse set of U.S. B. graminis f. sp. tritici isolates, and while the population as a whole remains relatively sensitive, some quantitative loss of efficacy was observed.

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.

Comparative analytical performance of multiple plasma Aß42 and Aß40 assays and their ability to predict positron emission tomography amyloid positivity.

INTRODUCTION: This report details the approach taken to providing a dataset allowing for analyses on the performance of recently developed assays of amyloid beta (Aß) peptides in plasma and the extent to which they improve the prediction of amyloid positivity. METHODS: Alzheimer's Disease Neuroimaging Initiative plasma samples with corresponding amyloid positron emission tomography (PET) data were run on six plasma Aß assays. Statistical tests were performed to determine whether the plasma Aß measures significantly improved the area under the receiver operating characteristic curve for predicting amyloid PET status compared to age and apolipoprotein E (APOE) genotype. RESULTS: The age and APOE genotype model predicted amyloid status with an area under the curve (AUC) of 0.75. Three assays improved AUCs to 0.81, 0.81, and 0.84 (P < .05, uncorrected for multiple comparisons). DISCUSSION: Measurement of Aß in plasma contributes to addressing the amyloid component of the ATN (amyloid/tau/neurodegeneration) framework and could be a first step before or in place of a PET or cerebrospinal fluid screening study. HIGHLIGHTS: The Foundation of the National Institutes of Health Biomarkers Consortium evaluated six plasma amyloid beta (Aß) assays using Alzheimer's Disease Neuroimaging Initiative samples. Three assays improved prediction of amyloid status over age and apolipoprotein E (APOE) genotype. Plasma Aß42/40 predicted amyloid positron emission tomography status better than Aß42 or Aß40 alone.

Multiple insertions of COIN, a novel maize Foldback transposable element, in the Conring gene cause a spontaneous progressive cell death phenotype.

Similar progressive leaf lesion phenotypes, named conring for "concentric ring," were identified in 10 independently derived maize lines. Complementation and mapping experiments indicated that the phenotype had the same genetic basis in each line - a single recessive gene located in a 1.1-Mb region on chromosome 2. Among the 15 predicted genes in this interval, Zm00001d003866 (subsequently renamed Conring or Cnr) had insertions of four related 138 bp transposable element (TE) sequences at precisely the same site in exon 4 in nine of the 10 cnr alleles. The 10th cnr allele had a distinct insertion of 226 bp of in exon 3. Genetic evidence suggested that the 10 cnr alleles were independently derived, and arose during the derivation of each line. The four TEs, named COINa (for COnring INsertion) through COINd, have not been previously characterized and consist entirely of imperfect 69-bp terminal inverted repeats characteristic of the Foldback class of TEs. They belong to three clades of a family of maize TEs comprising hundreds of sequences in the genome of the B73 maize line. COIN elements preferentially insert at TNA sequences with a preference for C and G nucleotides in the immediately flanking 5' and 3' regions, respectively. They produce a three-base target site duplication and do not have homology to other characterized TEs. We propose that Cnr is an unstable gene that is mutated insertionally at high frequency, most commonly due to COIN element insertions at a specific site in the gene.

Sensitivity of the U.S. Blumeria graminis f. sp. tritici Population to Demethylation Inhibitor Fungicides.

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is managed in the United States with cultivar resistance and foliar fungicides. Despite high levels of fungicide sensitivity in other cereal mildew populations, fungicide sensitivity of U.S. B. graminis f. sp. tritici has never been evaluated. Almost 400 B. graminis f. sp. tritici isolates were collected from 15 U.S. states over 2 years and phenotyped for sensitivity to two widely used demethylation inhibitor (DMI) fungicides, tebuconazole and prothioconazole. A large range of sensitivity to both DMIs was observed, with more insensitive isolates originating from the eastern United States (Great Lakes, Mid-Atlantic, and Southeast regions) and more sensitive isolates from central states (Plains region, Arkansas, and Missouri). Cross-resistance was indicated by a positive although weak association between tebuconazole and prothioconazole sensitivities at all levels of analysis (EC50 values, P < 0.0001). A possible fitness cost was also associated with prothioconazole insensitivity (P = 0.0307) when analyzed at the state population level. This is the first assessment of fungicide sensitivity in the U.S. B. graminis f. sp. tritici population, and it produced evidence of regional selection for reduced DMI efficacy. The observation of reduced sensitivity to DMI fungicides in the eastern United States underlines the importance of rotating between chemistry classes to maintain the effectiveness of DMIs in U.S. wheat production. Although cross-resistance was demonstrated, variability in the relationship of EC50 values for tebuconazole and prothioconazole also suggests that multiple mechanisms influence B. graminis f. sp. tritici isolate responses to these two DMI fungicides.

Distinct domains of the AVRPM3A2/F2 avirulence protein from wheat powdery mildew are involved in immune receptor recognition and putative effector function.

Recognition of the AVRPM3A2/F2 avirulence protein from powdery mildew by the wheat PM3A/F immune receptor induces a hypersensitive response after co-expression in Nicotiana benthamiana. The molecular determinants of this interaction and how they shape natural AvrPm3a2/f2 allelic diversity are unknown. We sequenced the AvrPm3a2/f2 gene in a worldwide collection of 272 mildew isolates. Using the natural polymorphisms of AvrPm3a2/f2 as well as sequence information from related gene family members, we tested 85 single-residue-altered AVRPM3A2/F2 variants with PM3A, PM3F and PM3FL456P/Y458H (modified for improved signaling) in Nicotiana benthamiana for effects on recognition. An intact AvrPm3a2/f2 gene was found in all analyzed isolates and the protein variant recognized by PM3A/F occurred globally at high frequencies. Single-residue alterations in AVRPM3A2/F2 mostly disrupted, but occasionally enhanced, the recognition response by PM3A, PM3F and PM3FL456P/Y458H . Residues enhancing hypersensitive responses constituted a protein domain separate from both naturally occurring polymorphisms and positively selected residues of the gene family. These results demonstrate the utility of using gene family sequence diversity to screen residues for their role in recognition. This approach identified a putative interaction surface in AVRPM3A2/F2 not polymorphic in natural alleles. We conclude that molecular mechanisms besides recognition drive AvrPm3a2/f2 diversification.

Virulence Differences in Blumeria graminis f. sp. tritici from the Central and Eastern United States.

Wheat powdery mildew is a disease of global importance that occurs across a wide geographic area in the United States. A virulence survey of Blumeria graminis f. sp. tritici, the causal agent, was conducted by sampling 36 wheat fields in 15 U.S. states in the years 2013 and 2014. Using a hierarchical sampling protocol, isolates were derived from three separated plants at each of five separated sites within each field in order to assess the spatial distribution of pathotypes. In total, 1,017 isolates from those fields were tested individually on single-gene differential cultivars containing a total of 21 powdery mildew resistance (Pm) genes. Several recently introgressed mildew resistance genes from wild wheat relatives (Pm37, Pm53, MlAG12, NCAG13, and MlUM15) exhibited complete or nearly complete resistance to all local B. graminis f. sp. tritici populations from across the sampled area. One older gene, Pm4b, also retained at least some efficacy across the sampled area. The B. graminis f. sp. tritici population sampled from Arkansas and Missouri, on the western edge of the eastern soft red winter wheat region, had virulence profiles more similar to other soft wheat mildew populations than to the geographically closer population from hard wheat fields in the Plains states of Oklahoma, Nebraska, and Kansas. The Plains population differed in that it was avirulent to several Pm genes long defeated in the soft-wheat-growing areas. Virulence complexity was greatest east of the Mississippi River, and diminished toward the west. Several recently introgressed Pm genes (Pm25, Pm34, Pm35, and NCA6) that are highly effective against mildew in the field in North Carolina were unexpectedly susceptible to eastern-U.S. B. graminis f. sp. tritici populations in detached-leaf tests. Sampled fields displayed a wide range of pathotype diversity and spatial distribution, suggesting that epidemics are caused by varying numbers of pathotypes in all regions. The research confirmed that most long-used Pm genes are defeated in the eastern United States, and the U.S. B. graminis f. sp. tritici population has different virulence profiles in the hard- and soft-wheat regions, which are likely maintained by host selection, isolation by distance, and west-to-east gene flow.

BMP signaling regulates the tempo of adult hippocampal progenitor maturation at multiple stages of the lineage.

Novel environmental stimuli, such as running and learning, increase proliferation of adult hippocampal neural stem cells (NSCs) and enlarge the population of new neurons. However, it remains unclear how increased numbers of new neurons can be generated in a time frame far shorter than the time required for proliferating stem cells to generate these neurons. Here, we show that bone morphogenetic protein (BMP) signaling in the subgranular zone regulates the tempo of neural progenitor cell (NPC) maturation by directing their transition between states of quiescence and activation at multiple stages along the lineage. Virally mediated overexpression of BMP4 caused NPC cell cycle exit and slowed the normal maturation of NPCs, resulting in a long-term reduction in neurogenesis. Conversely, overexpression of the BMP inhibitor noggin promoted NPC cell cycle entry and accelerated NPC maturation. Similarly, BMP receptor type 2 (BMPRII) ablation in Ascl1(+) intermediate NPCs accelerated their maturation into neurons. Importantly, ablation of BMPRII in GFAP(+) stem cells accelerated maturation without depleting the NSC pool, indicating that an increased rate of neurogenesis does not necessarily diminish the stem cell population. Thus, inhibition of BMP signaling is a mechanism for rapidly expanding the pool of new neurons in the adult hippocampus by tipping the balance between quiescence/activation of NPCs and accelerating the rate at which they mature into neurons.

Head-to-head comparison of leading blood tests for Alzheimer's disease pathology.

INTRODUCTION: Blood tests have the potential to improve the accuracy of Alzheimer disease (AD) clinical diagnosis, which will enable greater access to AD-specific treatments. This study compared leading commercial blood tests for amyloid pathology and other AD-related outcomes. METHODS: Plasma samples from the Alzheimers Disease Neuroimaging Initiative were assayed with AD blood tests from C2N Diagnostics, Fujirebio Diagnostics, ALZPath, Janssen, Roche Diagnostics, and Quanterix. Outcomes measures were amyloid positron emission tomography (PET), tau PET, cortical thickness, and dementia severity. Logistic regression models assessed the classification accuracies of individual or combined plasma biomarkers for binarized outcomes, and Spearman correlations evaluated continuous relationships between individual plasma biomarkers and continuous outcomes. RESULTS: Measures of plasma p-tau217, either individually or in combination with other plasma biomarkers, had the strongest relationships with all AD outcomes. DISCUSSION: This study identified the plasma biomarker analytes and assays that most accurately classified amyloid pathology and other AD-related outcomes.

Nutrition state of science and dementia prevention: recommendations of the Nutrition for Dementia Prevention Working Group.

Observational studies suggest that nutritional factors have a potential cognitive benefit. However, systematic reviews of randomised trials of dietary and nutritional supplements have reported largely null effects on cognitive outcomes and have highlighted study inconsistencies and other limitations. In this Personal View, the Nutrition for Dementia Prevention Working Group presents what we consider to be limitations in the existing nutrition clinical trials for dementia prevention. On the basis of this evidence, we propose recommendations for incorporating dietary patterns and the use of genetic, and nutrition assessment tools, biomarkers, and novel clinical trial designs to guide future trial developments. Nutrition-based research has unique challenges that could require testing both more personalised interventions in targeted risk subgroups, identified by nutritional and other biomarkers, and large-scale and pragmatic study designs for more generalisable public health interventions across diverse populations.

Does Using Humor to Cope With Stress Justify Making Fun of Patients?

This article considers 3 reasons for derogatory humor in clinical settings and argues that when such humor is directed at patients without understanding their complex histories, it can diminish the therapeutic relationship rather than serve as a coping strategy. This article also investigates how narrative medicine can guide deeper understanding of the motivations for using humor in clinical settings, why humor is directed at a particular person or group, and why derogatory, cynical, or dark humor might be unethical and unprofessional. Colleagues and mentors are essential for guiding students' and trainees' professional development and for helping them cultivate coping strategies that do not cause harm.

TGF-ß Family Signaling in Neural and Neuronal Differentiation, Development, and Function.

Signaling by the transforming growth factor ß (TGF-ß) family is necessary for proper neural development and function throughout life. Sequential waves of activation, inhibition, and reactivation of TGF-ß family members regulate numerous elements of the nervous system from the earliest stages of embryogenesis through adulthood. This review discusses the expression, regulation, and function of TGF-ß family members in the central nervous system at various developmental stages, beginning with induction and patterning of the nervous system to their importance in the adult as modulators of inflammatory response and involvement in degenerative diseases.

Increased bone morphogenetic protein signaling contributes to age-related declines in neurogenesis and cognition.

Aging is associated with decreased neurogenesis in the hippocampus and diminished hippocampus-dependent cognitive functions. Expression of bone morphogenetic protein 4 (BMP4) increases with age by more than 10-fold in the mouse dentate gyrus while levels of the BMP inhibitor, noggin, decrease. This results in a profound 30-fold increase in phosphorylated-SMAD1/5/8, the effector of canonical BMP signaling. Just as observed in mice, a profound increase in expression of BMP4 is observed in the dentate gyrus of humans with no known cognitive abnormalities. Inhibition of BMP signaling either by overexpression of noggin or transgenic manipulation not only increases neurogenesis in aging mice, but remarkably, is associated with a rescue of cognitive deficits to levels comparable to young mice. Additive benefits are observed when combining inhibition of BMP signaling and environmental enrichment. These findings indicate that increased BMP signaling contributes significantly to impairments in neurogenesis and to cognitive decline associated with aging, and identify this pathway as a potential druggable target for reversing age-related changes in cognition.

Systematic repression of transcription factors reveals limited patterns of gene expression changes in ES cells.

Networks of transcription factors (TFs) are thought to determine and maintain the identity of cells. Here we systematically repressed each of 100 TFs with shRNA and carried out global gene expression profiling in mouse embryonic stem (ES) cells. Unexpectedly, only the repression of a handful of TFs significantly affected transcriptomes, which changed in two directions/trajectories: one trajectory by the repression of either Pou5f1 or Sox2; the other trajectory by the repression of either Esrrb, Sall4, Nanog, or Tcfap4. The data suggest that the trajectories of gene expression change are already preconfigured by the gene regulatory network and roughly correspond to extraembryonic and embryonic fates of cell differentiation, respectively. These data also indicate the robustness of the pluripotency gene network, as the transient repression of most TFs did not alter the transcriptomes.

Generation of mouse ES cell lines engineered for the forced induction of transcription factors.

Here we report the generation and characterization of 84 mouse ES cell lines with doxycycline-controllable transcription factors (TFs) which, together with the previous 53 lines, cover 7-10% of all TFs encoded in the mouse genome. Global gene expression profiles of all 137 lines after the induction of TFs for 48 hrs can associate each TF with the direction of ES cell differentiation, regulatory pathways, and mouse phenotypes. These cell lines and microarray data provide building blocks for a variety of future biomedical research applications as a community resource.

Uncovering early response of gene regulatory networks in ESCs by systematic induction of transcription factors.

To examine transcription factor (TF) network(s), we created mouse ESC lines, in each of which 1 of 50 TFs tagged with a FLAG moiety is inserted into a ubiquitously controllable tetracycline-repressible locus. Of the 50 TFs, Cdx2 provoked the most extensive transcriptome perturbation in ESCs, followed by Esx1, Sox9, Tcf3, Klf4, and Gata3. ChIP-Seq revealed that CDX2 binds to promoters of upregulated target genes. By contrast, genes downregulated by CDX2 did not show CDX2 binding but were enriched with binding sites for POU5F1, SOX2, and NANOG. Genes with binding sites for these core TFs were also downregulated by the induction of at least 15 other TFs, suggesting a common initial step for ESC differentiation mediated by interference with the binding of core TFs to their target genes. These ESC lines provide a fundamental resource to study biological networks in ESCs and mice.