Bacteroidota inhibit microglia clearance of amyloid-beta and promote plaque deposition in Alzheimer's disease mouse models.

The gut microbiota and microglia play critical roles in Alzheimer's disease (AD), and elevated Bacteroides is correlated with cerebrospinal fluid amyloid-ß (Aß) and tau levels in AD. We hypothesize that Bacteroides contributes to AD by modulating microglia. Here we show that administering Bacteroides fragilis to APP/PS1-21 mice increases Aß plaques in females, modulates cortical amyloid processing gene expression, and down regulates phagocytosis and protein degradation microglial gene expression. We further show that administering Bacteroides fragilis to aged wild-type male and female mice suppresses microglial uptake of Aß1-42 injected into the hippocampus. Depleting murine Bacteroidota with metronidazole decreases amyloid load in aged 5xFAD mice, and activates microglial pathways related to phagocytosis, cytokine signaling, and lysosomal degradation. Taken together, our study demonstrates that members of the Bacteroidota phylum contribute to AD pathogenesis by suppressing microglia phagocytic function, which leads to impaired Aß clearance and accumulation of amyloid plaques.

Perinatal maternal undernutrition in baboons modulates hepatic mitochondrial function but not metabolites in aging offspring.

We previously demonstrated in baboons that maternal undernutrition (MUN), achieved by 70 % of control nutrition, impairs fetal liver function, but long-term changes associated with aging in this model remain unexplored. Here, we assessed clinical phenotypes of liver function, mitochondrial bioenergetics, and protein abundance in adult male and female baboons exposed to MUN during pregnancy and lactation and their control counterparts. Plasma liver enzymes were assessed enzymatically. Liver glycogen, choline, and lipid concentrations were quantified by magnetic resonance spectroscopy. Mitochondrial respiration in primary hepatocytes under standard culture conditions and in response to metabolic (1 mM glucose) and oxidative (100 µM H 2 O 2 ) stress were assessed with Seahorse XFe96. Hepatocyte mitochondrial membrane potential (MMP) and protein abundance were determined by tetramethylrhodamine ethyl ester staining and immunoblotting, respectively. Liver enzymes and metabolite concentrations were largely unaffected by MUN, except for higher aspartate aminotransferase levels in MUN offspring when male and female data were combined. Oxygen consumption rate, extracellular acidification rate, and MMP were significantly higher in male MUN offspring relative to control animals under standard culture. However, in females, cellular respiration was similar in control and MUN offspring. In response to low glucose challenge, only control male hepatocytes were resistant to low glucose-stimulated increase in basal and ATP-linked respiration. H 2 O 2 did not affect hepatocyte mitochondrial respiration. Protein markers of mitochondrial respiratory chain subunits, biogenesis, dynamics, and antioxidant enzymes were unchanged. Male-specific increases in mitochondrial bioenergetics in MUN offspring may be associated with increased energy demand in these animals. The similarity in systemic liver parameters suggests that changes in hepatocyte bioenergetics capacity precede detectable circulatory hepatic defects in MUN offspring and that the mitochondria may be an orchestrator of liver programming outcome.

Genetic characterization of a captive marmoset (Callithrix jacchus) colony using genotype-by-sequencing.

The marmoset is a fundamental nonhuman primate model for the study of aging, neurobiology, and many other topics. Genetic management of captive marmoset colonies is complicated by frequent chimerism in the blood and other tissues, a lack of tools to enable cost-effective, genome-wide interrogation of variation, and historic mergers and migrations of animals between colonies. We implemented genotype-by-sequencing (GBS) of hair follicle derived DNA (a minimally chimeric DNA source) of 82 marmosets housed at the Southwest National Primate Research Center (SNPRC). Our primary goals were the genetic characterization of our marmoset population for pedigree verification and colony management and to inform the scientific community of the functional genetic makeup of this valuable resource. We used the GBS data to reconstruct the genetic legacy of recent mergers between colonies, to identify genetically related animals whose relationships were previously unknown due to incomplete pedigree information, and to show that animals in the SNPRC colony appear to exhibit low levels of inbreeding. Of the >99,000 single-nucleotide variants (SNVs) that we characterized, >9800 are located within gene regions known to harbor pathogenic variants of clinical significance in humans. Overall, we show the combination of low-resolution (sparse) genotyping using hair follicle DNA is a powerful strategy for the genetic management of captive marmoset colonies and for identifying potential SNVs for the development of biomedical research models.

Differential mitochondrial bioenergetics and cellular resilience in astrocytes, hepatocytes, and fibroblasts from aging baboons.

Biological resilience, broadly defined as the ability to recover from an acute challenge and return to homeostasis, is of growing importance to the biology of aging. At the cellular level, there is variability across tissue types in resilience and these differences are likely to contribute to tissue aging rate disparities. However, there are challenges in addressing these cell-type differences at regional, tissue, and subject level. To address this question, we established primary cells from aged male and female baboons between 13.3 and 17.8 years spanning across different tissues, tissue regions, and cell types including (1) fibroblasts from skin and from the heart separated into the left ventricle (LV), right ventricle (RV), left atrium (LA), and right atrium (RA); (2) astrocytes from the prefrontal cortex and hippocampus; and (3) hepatocytes. Primary cells were characterized by their cell surface markers and their cellular respiration was assessed with Seahorse XFe96. Cellular resilience was assessed by modifying a live-cell imaging approach; we previously reported that monitors proliferation of dividing cells following response and recovery to oxidative (50 µM-H2O2), metabolic (1 mM-glucose), and proteostasis (0.1 µM-thapsigargin) stress. We noted significant differences even among similar cell types that are dependent on tissue source and the diversity in cellular response is stressor-specific. For example, astrocytes had a higher oxygen consumption rate and exhibited greater resilience to oxidative stress (OS) than both fibroblasts and hepatocytes. RV and RA fibroblasts were less resilient to OS compared with LV and LA, respectively. Skin fibroblasts were less impacted by proteostasis stress compared to astrocytes and cardiac fibroblasts. Future studies will test the functional relationship of these outcomes to the age and developmental status of donors as potential predictive markers.

Genetic regulatory effects in response to a high-cholesterol, high-fat diet in baboons.

Steady-state expression quantitative trait loci (eQTLs) explain only a fraction of disease-associated loci identified through genome-wide association studies (GWASs), while eQTLs involved in gene-by-environment (GxE) interactions have rarely been characterized in humans due to experimental challenges. Using a baboon model, we found hundreds of eQTLs that emerge in adipose, liver, and muscle after prolonged exposure to high dietary fat and cholesterol. Diet-responsive eQTLs exhibit genomic localization and genic features that are distinct from steady-state eQTLs. Furthermore, the human orthologs associated with diet-responsive eQTLs are enriched for GWAS genes associated with human metabolic traits, suggesting that context-responsive eQTLs with more complex regulatory effects are likely to explain GWAS hits that do not seem to overlap with standard eQTLs. Our results highlight the complexity of genetic regulatory effects and the potential of eQTLs with disease-relevant GxE interactions in enhancing the understanding of GWAS signals for human complex disease using non-human primate models.

Differential mitochondrial bioenergetics and cellular resilience in astrocytes, hepatocytes, and fibroblasts from aging baboons.

Biological resilience, broadly defined as ability to recover from acute challenge and return to homeostasis, is of growing importance to the biology of aging. At the cellular level, there is variability across tissue types in resilience and these differences likely to contribute to tissue aging rate disparities. However, there are challenges in addressing these cell-type differences at regional, tissue and subject level. To address this question, we established primary cells from aged male and female baboons between 13.3-17.8 years spanning across different tissues, tissue regions, and cell types including: (1) fibroblasts from skin and from heart separated into left ventricle (LV), right ventricle (RV), left atrium (LA) and right atrium (RA), (2) astrocytes from the prefrontal cortex and hippocampus and (3) hepatocytes. Primary cells were characterized by their cell surface markers and their cellular respiration assessed with Seahorse XFe96. Cellular resilience was assessed by modifying a live-cell imaging approach we previously reported that monitors proliferation of dividing cells following response and recovery to oxidative (50µM-H2O2), metabolic (1mM-glucose) and proteostasis (0.1µM-thapsigargin) stress. We noted significant differences even among similar cell types that are dependent on tissue source and the diversity in cellular response is stressor specific. For example, astrocytes were more energetic and exhibited greater resilience to oxidative stress (OS) than both fibroblasts and hepatocytes. RV and RA fibroblasts were less resilient to OS compared with LV and LA respectively. Skin fibroblasts were less impacted by proteostasis stress compared to astrocytes and cardiac fibroblasts. Future studies will test the functional relationship of these outcomes to age and developmental status of donors as potential predictive markers.

Female baboon adrenal zona fasciculata and zona reticularis regulatory and functional proteins decrease across the life course.

Debate exists on life-course adrenocortical zonal function trajectories. Rapid, phasic blood steroid concentration changes, such as circadian rhythms and acute stress responses, complicate quantification. To avoid pitfalls and account for life-stage changes in adrenocortical activity indices, we quantified zonae fasciculata (ZF) and reticularis (ZR) across the life-course, by immunohistochemistry of key regulatory and functional proteins. In 28 female baboon adrenals (7.5-22.1 years), we quantified 12 key proteins involved in cell metabolism, division, proliferation, steroidogenesis (including steroid acute regulatory protein, StAR), oxidative stress, and glucocorticoid and mitochondrial function. Life-course abundance of ten ZF proteins decreased with age. Cell cycle inhibitor and oxidative stress markers increased. Seven of the 12 proteins changed in the same direction for ZR and ZF. Importantly, ZF StAR decreased, while ZR StAR was unchanged. Findings indicate ZF function decreased, and less markedly ZR function, with age. Causes and aging consequences of these changes remain to be determined.

Gamma-delta T cells suppress microbial metabolites that activate striatal neurons and induce repetitive/compulsive behavior in mice.

Intestinal γδ T cells play an important role in shaping the gut microbiota, which is critical not only for maintaining intestinal homeostasis but also for controlling brain function and behavior. Here, we found that mice deficient for γδ T cells (γδ-/-) developed an abnormal pattern of repetitive/compulsive (R/C) behavior, which was dependent on the gut microbiota. Colonization of WT mice with γδ-/- microbiota induced R/C behavior whereas colonization of γδ-/- mice with WT microbiota abolished the R/C behavior. Moreover, γδ-/- mice had elevated levels of the microbial metabolite 3-phenylpropanoic acid in their cecum, which is a precursor to hippurate (HIP), a metabolite we found to be elevated in the CSF. HIP reaches the striatum and activates dopamine type 1 (D1R)-expressing neurons, leading to R/C behavior. Altogether, these data suggest that intestinal γδ T cells shape the gut microbiota and their metabolites and prevent dysfunctions of the striatum associated with behavior modulation.

Implementation preferences for the management of sexually transmitted infections in the South African health system: a discrete choice experiment.

OBJECTIVES: Despite strengthening HIV prevention with the introduction of pre-exposure prophylaxis (PrEP), STI services have remained relatively unchanged and the standard of care remains syndromic management. We used a discrete choice experiment to investigate service users' preferences for the diagnosis and treatment of STIs in South Africa. METHODS: Between 1 March 2021 and 20 April 2021, a cross-sectional online questionnaire hosted on REDCap was administered through access links sent to WhatsApp support groups for HIV PrEP users and attendees of two primary healthcare clinics and two mobile facilities in the Eastern Cape and Gauteng provinces aged between 18 and 49 years. Participants either self-completed the questionnaire or received support from a research assistant. We used a conditional logit model for the initial analysis and latent class model (LCM) to establish class memberships, with results displayed as ORs and probabilities. RESULTS: We enrolled 496 individuals; the majority were female (69%) and <30 years (74%). The LCM showed two distinct groups. The first group, comprising 68% of the participants, showed a strong preference for self-sampling compared with no sampling (OR 2.16, 95% CI 1.62 to 2.88). A clinic follow-up appointment for treatment was less preferable to same-day treatment (OR 0.78, 95% CI 0.63 to 0.95). Contact slip from index patient (OR 0.86, 95% CI 0.76 to 0.96) and healthcare professional (HCP)-initiated partner notification (OR 0.63, 95% CI 0.55 to 0.73) were both less preferable than expedited partner treatment (EPT). The second group included 32% of participants with a lower preference for self-sampling compared with no sampling (OR 0.65, 95% CI 0.41 to 1.04). There was no treatment option that was significantly different from the others; however, there was a strong preference for HCP-initiated partner notification to EPT (OR 1.53, 95% CI 1.10 to 2.12). CONCLUSIONS: Our results suggest that service users preferred STI testing prior to treatment, with the majority preferring self-taken samples and receiving aetiology-based treatment on the same day.

Comparing the Integration of Syndromic versus Etiological Management of Sexually Transmitted Infections Into HIV Pre-Exposure Prophylaxis Services for Adolescent Girls and Young Women, in South Africa.

South Africa has a high incidence of human immunodeficiency virus and sexually transmitted infections (STIs), particularly among adolescent girls and young women. National and global guidelines recommend varied strategies for integrating STI and pre-exposure prophylaxis (PrEP) services. PURPOSE: This paper describes the implementation of a syndromic compared to an etiological approach to STI integration within PrEP services in South Africa. METHODS: We analysed program data from eight fixed and four mobile clinics to describe a cascade of STI care and integration of syndromic management among clients accessing PrEP services. Diagnostic testing was conducted in a subset of clients to determine the prevalence of STIs and estimate the burden of disease missed using a syndromic approach. RESULTS: Between December 2018 and December 2021, 22,505 clients sought services and a high proportion (92.9%) was screened for STI symptoms. Of these, 9% of females and 3% of males had symptoms and 89.5% had recorded treatment. In a subset of PrEP clients (406 females, 70 males) screened through laboratory testing, chlamydia was identified in 25.7% of female and 20.0% of male samples, gonorrhea in 14.1% of female and 18.6% of male samples, and syphilis in 2.3% of female and 1.4% of male samples. Highest prevalence was found among females aged 18-20 years. DISCUSSION: Syndromic STI screening and management can be integrated into routine PrEP service delivery and can identify symptomatic STIs, but misses asymptomatic infections. PrEP clients have a high prevalence of treatable STIs. Etiologic approaches can identify more infections than syndromic screening, but cheap point-of-care tests are needed.

Mental Health Needs of Adolescent and Young Adult PrEP Users in South Africa: Implications for Sexual and Reproductive Health Programming.

PURPOSE: Poor mental health is associated with sexual and reproductive health (SRH) risks, including human immunodeficiency virus (HIV) and pre-exposure prophylaxis discontinuation. Adolescents and young people (AYP) are vulnerable to HIV and depression. This paper describes the prevalence and severity of depression and associated factors in AYP accessing SRH services in South Africa. METHODS: A cross-sectional analysis of enrollment data (January 2019 to December 2021) from a cohort of individuals receiving pre-exposure prophylaxis services at eight clinics in three provinces in South Africa was conducted. Females (n = 1,074) and males (n = 231) aged 15-24 years were included. Interviewer-administered questionnaires were conducted, and the prevalence and severity of depression assessed using the Patient Health Questionnaire-9. Multivariate analysis was used to identify factors associated with depression. RESULTS: Over 40% of participants had experienced any depression symptoms (43.7% of females, 38.5% of males). For males, experiencing intimate partner violence was the only predictor of depression symptoms (adjusted odds ratio (AOR) 8.81, 95% confidence intervals (CI) 1.03-75.44). For females, living with both parents (AOR 1.70, 95% CI 1.15-2.51), having transactional sex (AOR 1.63, 95% CI 1.00-2.65), experiencing any intimate partner violence (AOR 1.96, 95% CI 1.34-2.89), and using drugs (AOR 1.78, 95% CI 1.03-3.11) were all positively associated with depression symptoms. Resilience was a protective factor against depression symptoms for both sexes (males: AOR 0.96, 95% CI 0.93-0.98; females: AOR 0.96, 95% CI 0.95-0.97). DISCUSSION: There is a high burden of depression among AYP accessing SRH services in South Africa. Mental health screening should be integrated into SRH and HIV prevention programs for AYP.

Patterns of HIV Pre-exposure Prophylaxis use Among Adolescent Girls and Young Women Accessing Routine Sexual and Reproductive Health services in South Africa.

PURPOSE: This study describes the patterns of pre-exposure prophylaxis (PrEP) use among adolescent girls and young women (AGYW) initiated on daily oral PrEP for the prevention of HIV, within routine sexual and reproductive health services in South Africa. METHODS: We analysed clinical and survey data from a nested cohort of 967 AGYW initiated on oral PrEP between January 2019 and December 2021 in four geographical clusters in South Africa. We describe the periods of PrEP use, and the proportion who discontinued and subsequently restarted PrEP. Logistic regression analyses were conducted to determine factors associated with early PrEP discontinuation, PrEP use for ≥4 months and PrEP restart. RESULTS: PrEP use for ≤1 month was high (68.6%), although 27% returned and restarted PrEP; and 9% restarted more than once. Initiating PrEP at a mobile clinic (AOR 2.10, 95% CI 1.51 - 2.93) and having a partner known to be HIV negative or whose HIV status was unknown (AOR 7.11, 95% CI 1.45 - 34.23; AOR 6.90, 95% CI 1.44 - 33.09) were associated with PrEP use for ≤1 month. AGYW receiving injectable contraceptives were more likely to restart PrEP (AOR 1.61, 95% CI 1.10 - 2.35). Compared to those aged 15-17 years, participants 18 - 20 and 21 - 24 years were less likely to restart PrEP (AOR 0.51, 95% CI 0.35 - 0.74; AOR 0.60, 95%, CI 0.41 - 0.87), as were those initiating PrEP at a mobile clinic compared to a fixed facility (AOR 0.66, 95% CI 0.47 - 0.92). DISCUSSION: Although early PrEP discontinuation was high, it appears that PrEP use is frequently cyclical in nature. Further research is needed to determine if these cycles of PrEP correlate to periods of perceived or actual vulnerability to HIV, which may also be cyclical. PrEP delivery presents a unique opportunity to address multiple unmet health needs of young people.

The Use of HIV Pre-exposure Prophylaxis Among Men Accessing Routine Sexual and Reproductive Health Services in South Africa.

PURPOSE: This study describes a cohort of men seeking oral pre-exposure prophylaxis (PrEP) services and explores their patterns of PrEP use within an implementation project seeking to integrate PrEP provision within sexual and reproductive health services in public health clinics in South Africa. METHODS: Routine program and survey data from 364 males initiated on oral PrEP between July 2020 and May 2022 were analyzed. PrEP use was examined, including time to first discontinuation and restart patterns. Factors associated with early PrEP discontinuation and PrEP restart were analyzed. RESULTS: Despite primarily focusing on access for adolescent girls and young women, PrEP services reached males with HIV prevention needs. PrEP use for ≤1 month (early discontinuation) was high at 58%; however, 18% restarted on PrEP, with 4% restarting repeatedly. Having depression symptoms was associated with early PrEP discontinuation (adjusted odds ratio [AOR]: 1.71, 95% CI [confidence interval]: 1.06-2.78). Those ≥25 years were less likely to discontinue early, as were those with a partner treated for a sexually transmitted infection in the preceding three months (AOR: 0.33, 95% CI: 0.13-0.84) and those who had been circumcised (AOR: 0.59, 95% CI: 0.36-0.96). Those 18-20 years old were less likely to restart PrEP than those ≥25 years (AOR: 0.43, 95% CI: 0.19-0.97), as were those whose partner's HIV status was unknown (AOR: 0.33, 95% CI: 0.12-0.88). DISCUSSION: This study identified interest and uptake of oral PrEP among an underrepresented population of predominantly heterosexual males seeking sexual and reproductive health services. It found high rates of early PrEP discontinuation, with a subset returning to restart PrEP. Further research is needed to determine whether these periods of PrEP use are associated with periods of HIV risk.

Cardiac Molecular Analysis Reveals Aging-Associated Metabolic Alterations Promoting Glycosaminoglycans Accumulation Via Hexosamine Biosynthetic Pathway.

Age is a prominent risk factor for cardiometabolic disease, and often leads to heart structural and functional changes. However, precise molecular mechanisms underlying cardiac remodeling and dysfunction resulting from physiological aging per se remain elusive. Understanding these mechanisms requires biological models with optimal translation to humans. Previous research demonstrated that baboons undergo age-related reduction in ejection fraction and increased heart sphericity, mirroring changes observed in humans. The goal of this study was to identify early cardiac molecular alterations that precede functional adaptations, shedding light on the regulation of age-associated changes. We performed unbiased transcriptomics of left ventricle (LV) samples from female baboons aged 7.5-22.1 years (human equivalent ~30-88 years). Weighted-gene correlation network and pathway enrichment analyses were performed to identify potential age-associated mechanisms in LV, with histological validation. Myocardial modules of transcripts negatively associated with age were primarily enriched for cardiac metabolism, including oxidative phosphorylation, tricarboxylic acid cycle, glycolysis, and fatty-acid ß-oxidation. Transcripts positively correlated with age suggest upregulation of glucose uptake, pentose phosphate pathway, and hexosamine biosynthetic pathway (HBP), indicating a metabolic shift towards glucose-dependent anabolic pathways. Upregulation of HBP commonly results in increased glycosaminoglycan precursor synthesis. Transcripts involved in glycosaminoglycan synthesis, modification, and intermediate metabolism were also upregulated in older animals, while glycosaminoglycan degradation transcripts were downregulated with age. These alterations would promote glycosaminoglycan accumulation, which was verified histologically. Upregulation of extracellular matrix (ECM)-induced signaling pathways temporally coincided with glycosaminoglycan accumulation. We found a subsequent upregulation of cardiac hypertrophy-related pathways and an increase in cardiomyocyte width. Overall, our findings revealed a transcriptional shift in metabolism from catabolic to anabolic pathways that leads to ECM glycosaminoglycan accumulation through HBP prior to upregulation of transcripts of cardiac hypertrophy-related pathways. This study illuminates cellular mechanisms that precede development of cardiac hypertrophy, providing novel potential targets to remediate age-related cardiac diseases.

Evaluation of a carepartner-integrated telehealth gait rehabilitation program for persons with stroke: study protocol for a feasibility study.

BACKGROUND: Despite family carepartners of individuals post-stroke experiencing high levels of strain and reduced quality of life, stroke rehabilitation interventions rarely address carepartner well-being or offer training to support their engagement in therapeutic activities. Our group has developed creative intervention approaches to support families during stroke recovery, thereby improving physical and psychosocial outcomes for both carepartners and stroke survivors. The purpose of this study is to test the feasibility of an adapted, home-based intervention (Carepartner Collaborative Integrative Therapy for Gait-CARE-CITE-Gait) designed to facilitate positive carepartner involvement during home-based training targeting gait and mobility. METHODS: This two-phased design will determine the feasibility of CARE-CITE-Gait, a novel intervention that leverages principles from our previous carepartner-focused upper extremity intervention. During the 4-week CARE-CITE-Gait intervention, carepartners review online video-based modules designed to illustrate strategies for an autonomy-supportive environment during functional mobility task practice, and the study team completes two 2-h home visits for dyad collaborative goal setting. In phase I, content validity, usability, and acceptability of the CARE-CITE-Gait modules will be evaluated by stroke rehabilitation content experts and carepartners. In phase II, feasibility (based on measures of recruitment, retention, intervention adherence, and safety) will be measured. Preliminary effects of the CARE-CITE-Gait will be gathered using a single-group, quasi-experimental design with repeated measures (two baseline visits 1 week apart, posttest, and 1-month follow-up) with 15 carepartner and stroke survivor dyads. Outcome data collectors will be blinded. Outcomes include psychosocial variables (family conflict surrounding stroke recovery, strain, autonomy support, and quality of life) collected from carepartners and measures of functional mobility, gait speed, stepping activity, and health-related quality of life collected from stroke survivors. DISCUSSION: The findings of the feasibility testing and preliminary data on the effects of CARE-CITE-Gait will provide justification and information to guide a future definitive randomized clinical trial. The knowledge gained from this study will enhance our understanding of and aid the development of rehabilitation approaches that address both carepartner and stroke survivor needs during the stroke recovery process. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05257928. Registered 25 February 2022. TRIAL STATUS: This trial was registered on ClinicalTrials.gov (NCT05257928) on March 25, 2022. Recruitment of participants was initiated on May 18, 2022.

Integrated multi-omics analysis of brain aging in female nonhuman primates reveals altered signaling pathways relevant to age-related disorders.

The prefrontal cortex (PFC) has been implicated as a key brain region responsible for age-related cognitive decline. Little is known about aging-related molecular changes in PFC that may mediate these effects. To date, no studies have used untargeted discovery methods with integrated analyses to determine PFC molecular changes in healthy female primates. We quantified PFC changes associated with healthy aging in female baboons by integrating multiple omics data types (transcriptomics, proteomics, metabolomics) from samples across the adult age span. Our integrated omics approach using unbiased weighted gene co-expression network analysis to integrate data and treat age as a continuous variable, revealed highly interconnected known and novel pathways associated with PFC aging. We found Gamma-aminobutyric acid (GABA) tissue content associated with these signaling pathways, providing 1 potential biomarker to assess PFC changes with age. These highly coordinated pathway changes during aging may represent early steps for aging-related decline in PFC functions, such as learning and memory, and provide potential biomarkers to assess cognitive status in humans.

Characterizing Early Cardiac Metabolic Programming via 30% Maternal Nutrient Reduction during Fetal Development in a Non-Human Primate Model.

Intra-uterine growth restriction (IUGR) is a common cause of fetal/neonatal morbidity and mortality and is associated with increased offspring predisposition for cardiovascular disease (CVD) development. Mitochondria are essential organelles in maintaining cardiac function, and thus, fetal cardiac mitochondria could be responsive to the IUGR environment. In this study, we investigated whether in utero fetal cardiac mitochondrial programming can be detectable in an early stage of IUGR pregnancy. Using a well-established nonhuman IUGR primate model, we induced IUGR by reducing by 30% the maternal diet (MNR), both in males (MNR-M) and in female (MNR-F) fetuses. Fetal cardiac left ventricle (LV) tissue and blood were collected at 90 days of gestation (0.5 gestation, 0.5 G). Blood biochemical parameters were determined and heart LV mitochondrial biology assessed. MNR fetus biochemical blood parameters confirm an early fetal response to MNR. In addition, we show that in utero cardiac mitochondrial MNR adaptations are already detectable at this early stage, in a sex-divergent way. MNR induced alterations in the cardiac gene expression of oxidative phosphorylation (OXPHOS) subunits (mostly for complex-I, III, and ATP synthase), along with increased protein content for complex-I, -III, and -IV subunits only for MNR-M in comparison with male controls, highlight the fetal cardiac sex-divergent response to MNR. At this fetal stage, no major alterations were detected in mitochondrial DNA copy number nor markers for oxidative stress. This study shows that in 90-day nonhuman primate fetuses, a 30% decrease in maternal nutrition generated early in utero adaptations in fetal blood biochemical parameters and sex-specific alterations in cardiac left ventricle gene and protein expression profiles, affecting predominantly OXPHOS subunits. Since the OXPHOS system is determinant for energy production in mitochondria, our findings suggest that these early IUGR-induced mitochondrial adaptations play a role in offspring's mitochondrial dysfunction and can increase predisposition to CVD in a sex-specific way.

Multi-omics Analysis of Aging Liver Reveals Changes in Endoplasmic Stress and Degradation Pathways in Female Nonhuman Primates.

The liver is critical for functions that support metabolism, immunity, digestion, detoxification, and vitamin storage. Aging is associated with severity and poor prognosis of various liver diseases such as nonalcoholic fatty liver disease (NAFLD). Previous studies have used multi-omic approaches to study liver diseases or to examine the effects of aging on the liver. However, to date, no studies have used an integrated omics approach to investigate aging-associated molecular changes in the livers of healthy female nonhuman primates. The goal of this study was to identify molecular changes associated with healthy aging in the livers of female baboons ( Papio sp., n=35) by integrating multiple omics data types (transcriptomics, proteomics, metabolomics) from samples across the adult age span. To integrate omics data, we performed unbiased weighted gene co-expression network analysis (WGCNA), and the results revealed 3 modules containing 3,149 genes and 33 proteins were positively correlated with age, and 2 modules containing 37 genes and 216 proteins were negatively correlated with age. Pathway enrichment analysis showed that unfolded protein response (UPR) and endoplasmic reticulum (ER) stress were positively associated with age, whereas xenobiotic metabolism and melatonin and serotonin degradation pathways were negatively associated with age. The findings of our study suggest that UPR and a reduction in reactive oxygen species generated from serotonin degradation could protect the liver from oxidative stress during the aging process in healthy female baboons.

Genetic regulatory effects in response to a high cholesterol, high fat diet in baboons.

Steady-state expression quantitative trait loci (eQTLs) explain only a fraction of disease-associated loci identified through genome-wide association studies (GWAS), while eQTLs involved in gene-by-environment (GxE) interactions have rarely been characterized in humans due to experimental challenges. Using a baboon model, we found hundreds of eQTLs that emerge in adipose, liver, and muscle after prolonged exposure to high dietary fat and cholesterol. Diet-responsive eQTLs exhibit genomic localization and genic features that are distinct from steady-state eQTLs. Furthermore, the human orthologs associated with diet-responsive eQTLs are enriched for GWAS genes associated with human metabolic traits, suggesting that context-responsive eQTLs with more complex regulatory effects are likely to explain GWAS hits that do not seem to overlap with standard eQTLs. Our results highlight the complexity of genetic regulatory effects and the potential of eQTLs with disease-relevant GxE interactions in enhancing the understanding of GWAS signals for human complex disease using nonhuman primate models.