Genetic architecture of RNA editing regulation in Alzheimer's disease across diverse ancestral populations.

Most Alzheimer's disease (AD)-associated genetic variants do not change protein coding sequence and thus likely exert their effects through regulatory mechanisms. RNA editing, the post-transcriptional modification of RNA bases, is a regulatory feature that is altered in AD patients that differs across ancestral backgrounds. Editing QTLs (edQTLs) are DNA variants that influence the level of RNA editing at a specific site. To study the relationship of DNA variants genome-wide, and particularly in AD-associated loci, with RNA editing, we performed edQTL analyses in self-reported individuals of African American (AF) or White (EU) race with corresponding global genetic ancestry averaging 82.2% African ancestry (AF) and 96.8% European global ancestry (EU) in the two groups, respectively. We used whole-genome genotyping array and RNA sequencing data from peripheral blood of 216 AD cases and 212 age-matched, cognitively intact controls. We identified 2144 edQTLs in AF and 3579 in EU, of which 1236 were found in both groups. Among these, edQTLs in linkage disequilibrium (r2 > 0.5) with AD-associated genetic variants in the SORL1, SPI1 and HLA-DRB1 loci were associated with sites that were differentially edited between AD cases and controls. While there is some shared RNA editing regulatory architecture, most edQTLs had distinct effects on the rate of RNA editing in different ancestral populations suggesting a complex architecture of RNA editing regulation. Altered RNA editing may be one possible mechanism for the functional effect of AD-associated variants and may contribute to observed differences in the genetic etiology of AD between ancestries.

Building a Community Partnership for the Development of Health Ministries Within the African American Community: The Triad Pastors Network.

African Americans continue to have worse health outcomes despite attempts to reduce health disparities. This is due, in part, to inadequate access to healthcare, but also to the health care and medical mistrust experienced by communities of color. Churches and worship centers have historically served as cultural centers of trusted resources for educational, financial, and health information within African American communities and a growing number of collaborations have developed between academic institutions and community/faith entities. Herein, we describe the infrastructure of a true and sustainable partnership developed with > 100 prominent faith leaders within the Piedmont Triad region of North Carolina for the purpose of developing or expanding existing health ministries within houses of worship, to improve health literacy and overall health long-term. The Triad Pastors Network is an asset-based partnership between the Maya Angelou Center for Health Equity at Wake Forest University School of Medicine and faith leaders in the Piedmont Triad region of North Carolina that was created under the guiding principles of community engagement to improve health equity and decrease health disparities experienced by African American communities. A partnership in which co-equality and shared governance are the core of the framework provides an effective means of achieving health-related goals in a productive and efficient manner. Faith-based partnerships are reliable approaches for improving the health literacy needed to address health disparities and inequities in communities of color.

Assessing Gender Differences on the Impact of COVID-19 on the Medical and Social Needs of Dementia Caregivers.

Our analyses aimed to assess health status and critical needs of caregivers of persons with dementia (PWD) during the COVID-19 pandemic by gender. Between March 2021 and August 2021, respondents (n = 267) were recruited from an Alzheimer's disease (AD) listserv at an US academic center to complete a questionnaire to capture sociodemographic data, caregiving characteristics, health status, status of COVID-19 testing, and COVID-19 preventative practices during the pandemic. Women caregivers reported needing assistance with caregiving responsibilities, whereas men caregivers needed assistance with health and social resources. More men caregivers also reported psychological distress compared to women caregivers. Our findings indicated significant differences in the resources needed and psychological distress of women and men who cared for PWD during the COVID-19 pandemic. The development of recommendations and resources with both men and women caregivers in mind may be beneficial to support informal caregivers during emergency situations.

Neuropsychiatric features in a multi-ethnic population with Alzheimer disease and mild cognitive impairment.

BACKGROUND: Alzheimer disease (AD) is more prevalent in African American (AA) and Hispanic White (HIW) compared to Non-Hispanic White (NHW) individuals. Similarly, neuropsychiatric symptoms (NPS) vary by population in AD. This is likely the result of both sociocultural and genetic ancestral differences. However, the impact of these NPS on AD in different groups is not well understood. METHODS: Self-declared AA, HIW, and NHW individuals were ascertained as part of ongoing AD genetics studies. Participants who scored higher than 0.5 on the Clinical Dementia Rating (CDR) Scale (CDR) were included. Group similarities and differences on Neuropsychiatric Inventory Questionnaire (NPI-Q) outcomes (NPI-Q total score, NPI-Q items) were evaluated using univariate ANOVAs and post hoc comparisons after controlling for sex and CDR stage. RESULTS: Our sample consisted of 498 participants (26% AA; 30% HIW; 44% NHW). Overall, NPI-Q total scores differed significantly between our groups, with HIW having the highest NPI-Q total scores, and by AD stage as measured by CDR. We found no significant difference in NPI-Q total score by sex. There were six NPI-Q items with comparable prevalence in all groups and six items that significantly differed between the groups (Anxiety, Apathy, Depression, Disinhibition, Elation, and Irritability). Further, within the HIW group, differences were found between Puerto Rican and Cuban American Hispanics across several NPI-Q items. Finally, Six NPI-Q items were more prevalent in the later stages of AD including Agitation, Appetite, Hallucinations, Irritability, Motor Disturbance, and Nighttime Behavior. CONCLUSIONS: We identified differences in NPS among HIW, AA, and NHW individuals. Most striking was the high burden of NPS in HIW, particularly for mood and anxiety symptoms. We suggest that NPS differences may represent the impact of sociocultural influences on symptom presentation as well as potential genetic factors rooted in ancestral background. Given the complex relationship between AD and NPS it is crucial to discern the presence of NPS to ensure appropriate interventions.

Leveraging African American family connectors for Alzheimer's disease genomic studies.

INTRODUCTION: The underrepresentation of African Americans (AAs) in Alzheimer's disease (AD) research may limit potential benefits from translational applications. This article describes an approach to recruit AA families into an AD genomic study and characteristics of seeds (family connectors) used to overcome recruitment barriers of AA families into AD research. METHODS: A four-step outreach and snowball sampling approach relying on family connectors was used to recruit AA families. Descriptive statistics of a profile survey were gathered to understand the demographic and health characteristics of family connectors. RESULTS: Twenty-five AA families (117 participants) were enrolled in the study via family connectors. Most family connectors self-identified as female (88%), were 60 years of age or older (76%), and attained post-secondary education (77%). DISCUSSION: Community-engaged strategies were essential to recruit AA families. Relationships between study coordinators and family connectors build trust early in the research process among AA families. HIGHLIGHTS: Community events were most effective for recruiting African American families. Family connectors were primarily female, in good health, and highly educated. Systematic efforts by researchers are necessary to "sell" a study to participants.

RNA editing alterations in a multi-ethnic Alzheimer disease cohort converge on immune and endocytic molecular pathways.

Little is known about the post-transcriptional mechanisms that modulate the genetic effects in the molecular pathways underlying Alzheimer disease (AD), and even less is known about how these changes might differ across diverse populations. RNA editing, the process that alters individual bases of RNA, may contribute to AD pathogenesis due to its roles in neuronal development and immune regulation. Here, we pursued one of the first transcriptome-wide RNA editing studies in AD by examining RNA sequencing data from individuals of both African-American (AA) and non-Hispanic White (NHW) ethnicities. Whole transcriptome RNA sequencing and RNA editing analysis were performed on peripheral blood specimens from 216 AD cases (105 AA, 111 NHW) and 212 gender matched controls (105 AA, 107 NHW). 449 positions in 254 genes and 723 positions in 371 genes were differentially edited in AA and NHW, respectively. While most differentially edited sites localized to different genes in AA and NHW populations, these events converged on the same pathways across both ethnicities, especially endocytic and inflammatory response pathways. Furthermore, these differentially edited sites were preferentially predicted to disrupt miRNA binding and induce nonsynonymous coding changes in genes previously associated with AD in molecular studies, including PAFAH1B2 and HNRNPA1. These findings suggest RNA editing is an important post-transcriptional regulatory program in AD pathogenesis.

Ancestral origin of ApoE ε4 Alzheimer disease risk in Puerto Rican and African American populations.

The ApoE ε4 allele is the most significant genetic risk factor for late-onset Alzheimer disease. The risk conferred by ε4, however, differs across populations, with populations of African ancestry showing lower ε4 risk compared to those of European or Asian ancestry. The cause of this heterogeneity in risk effect is currently unknown; it may be due to environmental or cultural factors correlated with ancestry, or it may be due to genetic variation local to the ApoE region that differs among populations. Exploring these hypotheses may lead to novel, population-specific therapeutics and risk predictions. To test these hypotheses, we analyzed ApoE genotypes and genome-wide array data in individuals from African American and Puerto Rican populations. A total of 1,766 African American and 220 Puerto Rican individuals with late-onset Alzheimer disease, and 3,730 African American and 169 Puerto Rican cognitively healthy individuals (> 65 years) participated in the study. We first assessed average ancestry across the genome ("global" ancestry) and then tested it for interaction with ApoE genotypes. Next, we assessed the ancestral background of ApoE alleles ("local" ancestry) and tested if ancestry local to ApoE influenced Alzheimer disease risk while controlling for global ancestry. Measures of global ancestry showed no interaction with ApoE risk (Puerto Rican: p-value = 0.49; African American: p-value = 0.65). Conversely, ancestry local to the ApoE region showed an interaction with the ApoE ε4 allele in both populations (Puerto Rican: p-value = 0.019; African American: p-value = 0.005). ApoE ε4 alleles on an African background conferred a lower risk than those with a European ancestral background, regardless of population (Puerto Rican: OR = 1.26 on African background, OR = 4.49 on European; African American: OR = 2.34 on African background, OR = 3.05 on European background). Factors contributing to the lower risk effect in the ApoE gene ε4 allele are likely due to ancestry-specific genetic factors near ApoE rather than non-genetic ethnic, cultural, and environmental factors.

Attitudes and Perceptions about Brain Donation Among African Americans: Implications for Recruitment into Alzheimer's Disease Research.

The objective of this study was to investigate attitudes toward brain donation and perceptions of medical research that influence brain donation among African Americans. Cross-sectional surveys were administered to African American community members (n = 227). Findings indicate that only 27% of respondents were willing to donate their brain. As medical mistrust was not found to be a significant barrier to research participation, there may be opportunity to increase brain donation by providing information about Alzheimer's disease and brain donation to potential donors and their families so that informed decisions about participating in research can be made.

Generation of an induced pluripotent stem cell line (UMi043-A) from an African American patient with Alzheimer's disease carrying an ABCA7 deletion (p.Arg578Alafs).

The ATP-binding cassette, subfamily A (ABC1), member 7 (ABCA7) gene is associated with Alzheimer's disease (AD) risk in populations of African, Asian, and European ancestry1-5. Numerous ABCA7 mutations contributing to risk have been identified, including a 44 base pair deletion (rs142076058) specific to individuals of African ancestry and predicted to cause a frameshift mutation (p.Arg578Alafs) (Cukier et al., 2016). The UMi043-A human induced pluripotent stem cell line was derived from an African American individual with AD who is heterozygous for this deletion and is a resource to further investigate ABCA7 and how this African-specific deletion may influence disease pathology.

Genetic analyses in multiplex families confirms chromosome 5q35 as a risk locus for Alzheimer's Disease in individuals of African Ancestry.

There is a paucity of genetic studies of Alzheimer Disease (AD) in individuals of African Ancestry, despite evidence suggesting increased risk of AD in the African American (AA) population. We performed whole-genome sequencing (WGS) and multipoint linkage analyses in 51 multi-generational AA AD families ascertained through the Research in African American Alzheimer Disease Initiative (REAAADI) and the National Institute on Aging Late Onset Alzheimer's disease (NIA-LOAD) Family Based Study. Variants were prioritized on minor allele frequency (<0.01), functional potential of coding and noncoding variants, co-segregation with AD and presence in multi-ancestry ADSP release 3 WGS data. We identified a significant linkage signal on chromosome 5q35 (HLOD=3.3) driven by nine families. Haplotype segregation analysis in the family with highest LOD score identified a 3'UTR variant in INSYN2B with the most functional evidence. Four other linked AA families harbor within-family shared variants located in INSYN2B's promoter or enhancer regions. This AA family-based finding shows the importance of diversifying population-level genetic data to better understand the genetic determinants of AD on a global scale.

Generalizability of Tau and Amyloid Plasma Biomarkers in Alzheimer's Disease Cohorts of Diverse Genetic Ancestries.

Introduction: Plasma phosphorylated threonine-181 of Tau and amyloid beta are biomarkers for differential diagnosis and preclinical detection of Alzheimer disease (AD). Given differences in AD risk across diverse populations, generalizability of existing biomarker data is not assured. Methods: In 2,086 individuals of diverse genetic ancestries (African American, Caribbean Hispanic, and Peruvians) we measured plasma pTau-181 and Aß42/Aß40. Differences in biomarkers between cohorts and clinical diagnosis groups and the potential discriminative performance of the two biomarkers were assessed. Results: pTau-181 and Aß42/Aß40 were consistent across cohorts. Higher levels of pTau181 were associated with AD while Aß42/Aß40 had minimal differences. Correspondingly, pTau-181 had greater predictive value than Aß42/Aß40, however, the area under the curve differed between cohorts. Discussion: pTau-181 as a plasma biomarker for clinical AD is generalizable across genetic ancestries, but predictive value may differ. Combining genomic and biomarker data from diverse individuals will increase understanding of genetic risk and refine clinical diagnoses.

African Ancestry Individuals with Higher Educational Attainment Are Resilient to Alzheimer's Disease Measured by pTau181.

Background: Cognitive and functional abilities in individuals with Alzheimer's disease (AD) pathology (ADP) are highly variable. Factors contributing to this variability are not well understood. Previous research indicates that higher educational attainment (EA) correlates with reduced cognitive impairments among those with ADP. While cognitive and functional impairments are correlated, they are distinguishable in their manifestations. Objective: To investigate whether levels of education are associated with functional impairments among those with ADP. Methods: This research involved 410 African American (AA) individuals (Institutional Review Boards 20070307, 01/27/2023) to ascertain whether EA correlates with functional resilience and if this effect varies between APOE ɛ4 carriers and non-carriers. Utilizing EA as a cognitive reserve proxy, CDR-FUNC as a functional difficulties measure, and blood pTau181 as an ADP proxy, the non-parametric Mann-Whitney U test assessed the relationship between EA and CDR-FUNC in individuals with advanced pTau181 levels. Results: The results showed that EA correlated with functional difficulties in AA individuals with high levels of pTau181, such that individuals with high EA are more likely to have better functional ability compared to those with lower EA (W = 730.5, p = 0.0007). Additionally, we found that the effect of high EA on functional resilience was stronger in ɛ4 non-carriers compared to ɛ4 carriers (W = 555.5, p = 0.022). Conclusion: This study extends the role of cognitive reserve and EA to functional performance showing that cognitive reserve influences the association between ADP burden and functional difficulties. Interestingly, this protective effect seems less pronounced in carriers of the strong genetic risk allele ɛ4.

Gender, Age and COVID-19 Vaccination Status in African American Adult Faith-Based Congregants in the Southeastern United States.

OBJECTIVES: The COVID-19 pandemic has revealed significant differences in COVID-19 vaccination rates, with African Americans reporting lower rates compared to other racial and ethnic groups. The purpose of these analyses was to assess whether COVID-19 vaccination status differed according to age in a sample of 1,240 African American adult congregants of faith-based organizations ages 18 years or older, and to examine whether this association was moderated by gender. DESIGN: We developed and administered a 75-item cross-sectional survey, the Triad Pastor's Network COVID-19 and COVID-19 Vaccination survey, to assess experiences and perceptions regarding the COVID-19 virus and vaccines. We assessed the association between age and having received > 1 dose of a COVID-19 vaccine using unadjusted and multivariable binary logistic regression models, and the interaction of age and gender with COVID-19 vaccination status in a multivariable model. RESULTS: Approximately 86% of participants reported having received ≥ 1 dose of a COVID-19 vaccine. The mean age (standard deviation) of the sample was 51.33 (16.62) years, and 70.9% of the sample was comprised of women. The age by gender interaction term in the multivariable model was significant (p = 0.005), prompting additional analyses stratified by gender. In women, increased age was significantly associated with higher odds of COVID-19 vaccination (odds ratio = 1.09; 95% Confidence Interval 1.06, 1.11; p < 0.001). In men, the association was not significant (p = 0.44). CONCLUSIONS: Older age was positively associated with COVID-19 vaccination in African American women, but not African American men, which may inform strategies to increase vaccination rates.

African ancestry APOE e4 non-carriers with higher educational attainment are resilient to Alzheimer disease pathology-specific blood biomarker pTau181.

Cognitive and functional abilities in individuals with Alzheimer disease (AD) pathology (ADP) show greater than expected variability. While most individuals show substantial impairments in these abilities, a considerable number show little or no impairments. Factors contributing to this variability are not well understood. For instance, multiple studies have shown that higher levels of education are associated with reduced cognitive impairments among those with ADP. However, it remains unclear whether higher levels of education are associated with functional impairments among those with ADP. We studied 410 AA individuals with advanced levels of pTau181 (a biomarker for ADP; individuals as those having log 10 (pTau181) level greater than one standard deviation above the mean) to determine whether EA (categorized as low EA for individuals with ≤ 8 years of education and high EA for those with >8 years) promotes functional resilience and whether this effect varies between APOE ε4 carriers and non-carriers. We used the four non-memory components of the Clinical Dementia Rating (CDR) to create a composite score (CDR-FUNC) to evaluate functional difficulties (scored from 0=no impairment to 12=severe). We employed the non-parametric Mann-Whitney U test to assess the relationship between EA and CDR-FUNC in advanced levels of pTau181 individuals. The results showed that EA promotes resilience to functional problems in AA individuals with advanced levels of pTau181, such that individuals with high EA are more likely to have better functional ability compared to those with lower EA (W=730.5, p=0.0007). Additionally, we found that the effect of high EA on functional resilience was stronger in ε4 non-carriers compared to ε4 carriers (W=555.5, p=0.022). This study extends the role of cognitive reserve and EA to functional performance showing that cognitive reserve influences the association between ADP burden and functional difficulties. Interestingly, this protective effect seems less pronounced in carriers of the strong genetic risk allele ε4. The results highlight the intricate interplay of genetic and non-genetic factors in AD progression, suggesting a need for more personalized strategies to manage functional decline in AD.

Assessing the Role of Trust in Public Health Agencies and COVID-19 Vaccination Status Among a Community Sample of African Americans in North Carolina.

BACKGROUND: Mistrust of the government and medical establishments are prominent reasons for vaccine hesitancy among African Americans (AAs). As COVID-19 research evolves in real time with some uncertainties remaining, AA communities may be less trusting of public health agencies. The purpose of these analyses was to assess the association between trust in public health agencies that recommend the COVID-19 vaccination and COVID-19 vaccination status among AAs in North Carolina. METHODS: A 75-item cross-sectional survey, the Triad Pastors Network COVID-19 and COVID-19 Vaccination survey, was developed and administered to African Americans in North Carolina. Multivariable logistic regression was used to examine the association between levels of trust in public health agencies who recommend the COVID-19 vaccine and COVID-19 vaccination status among AAs. RESULTS: Of the 1157 AAs included in these analyses, approximately 14% of AAs had not received the COVID-19 vaccine. These findings indicated that lower levels of trust in public health agencies significantly decreased the odds of getting the COVID-19 vaccination compared to those with higher levels of trust among AAs. The most trusted source for information on COVID-19 included federal agencies among all respondents. Among the vaccinated, primary care physicians were another trusted source of information. Pastors were another trusted source for those willing to be vaccinated. CONCLUSIONS: Despite the majority of the respondents in this sample receiving the COVID-19 vaccine, subgroups of AAs remain unvaccinated. Federal agencies have a high level of trust among AA adults; however, innovative approaches are needed to reach AAs who remain unvaccinated.

Recruiting intergenerational African American males for biomedical research Studies: a major research challenge.

The health and well-being of all individuals, independent of race, ethnicity, or gender, is a significant public health concern. Despite many improvements in the status of minority health, African American males continue to have the highest age-adjusted mortality rate of any race-sex group in the United States. Such disparities are accounted for by deaths from a number of diseases such as diabetes, human immunodeficiency virus (HIV), cancer, and cardiovascular disease, as well as by many historical and present social and cultural constructs that present as obstacles to better health outcomes. Distrust of the medical community, inadequate education, low socioeconomic status, social deprivation, and underutilized primary health care services all contribute to disproportionate health and health care outcomes among African Americans compared to their Caucasian counterparts. Results of clinical research on diseases that disproportionately affect African American males are often limited in their reliability due to common sampling errors existing in the majority of biomedical research studies and clinical trials. There are many reasons for underrepresentation of African American males in clinical trials, including their common recollection and interpretation of relevant historical of biomedical events where minorities were abused or exposed to racial discrimination or racist provocation. In addition, African American males continue to be less educated and more disenfranchised from the majority in society than Caucasian males and females and their African American female counterparts. As such, understanding their perceptions, even in early developmental years, about health and obstacles to involvement in research is important. In an effort to understand perspectives about their level of participation, motivation for participation, impact of education, and engagement in research, this study was designed to explore factors that impact their willingness to participate. Our research suggests that: (1) African American males across all ages are willing to participate in several types of research studies, even those that require human samples; (2) their level of participation is significantly influenced by education level; and (3) their decision to participate in research studies is motivated by civic duty, monetary compensation, and whether they or a relative has had the disease of interest. However, African American males, across all age groups, continue to report a lack of trust as a primary reason for their unwillingness to participate in biomedical research. There is an ongoing need to continue to seek advice, improve communication, and design research studies that garner trust and improve participation among African American males as a targeted underrepresented population. Such communication and dialogues should occur at all age levels of research development to assess. current attitudes and behaviors of African American males around participation.