Jessica Raper

In pediatric brain tumors medulloblastoma (MB) and diffuse midline glioma (DMG), tumor-associated myeloid cells (TAMs) support malignant progression by secreting paracrine growth factors and suppressing local immune function. We studied the potential for reversing this cancer-supportive phenotype by stimulating TAM pathogen receptors using ResiPOx, a brain-permeant, polyoxazoline nanoparticle formulation of the TLR7/8 agonist resiquimod. ResiPOx showed blood-brain barrier penetration and anti-tumor efficacy, extending progression-free survival (PFS) in mice with MB and DMG. Integrated cellular and molecular analysis including scRNA-seq showed that ResiPOx expanded TAM populations and reprogrammed TAMs toward anti-tumoral states, blocking paracrine IGF1 signaling and inducing local cytokine signaling and phagocytosis of tumor cells. In rhesus macaques, systemic ResiPOx was well tolerated and induced brain transcriptional patterns that resembled ResiPOx responses in DMG and MB mouse models, indicating effects in non-human primates that highlight translational potential. Our data show that ResiPOx reshapes the brain tumor microenvironment to inhibit tumor growth. As a systemically administered, brain penetrant immunomodulator, ResiPOx is able to reach multifocal and unresectable brain tumors, including MB and DMG.

Although congenital Zika virus (ZIKV) syndrome is well-characterized, the neurodevelopmental consequences of postnatal infection are understudied. We used a rhesus macaque (RM) model to investigate the consequences of postnatal ZIKV infection on brain and behavior. Male and female infant RMs infected with ZIKV at 1 month of age were compared to sex-, age-, and rearing-matched controls: uninfected and treated with Poly-IC as an innate immune control. ZIKV-infected infants showed poor state control in early infancy and increased hostility during an acute stressor. They displayed sex-specific behavioral alterations during caregiver separation though attachment bonds were preserved. MRI at 3 months revealed larger total cerebrospinal fluid (CSF) volume, reduced visual processing region volumes, and sex-specific brain structural alterations: males exhibited amygdala hypertrophy, whereas females had volumetric reductions in temporal-limbic and temporal-auditory cortices. These findings indicate that postnatal ZIKV infection is associated with alterations in sensory, social and emotion-regulatory systems and in CSF volume, that may warrant long-term monitoring of exposed children.

Congenital and early-life Zika virus (ZIKV) infection can result in neurologic deficits. Precise mechanisms of injury, especially in the more subtle presentation of postnatal infection, are not fully elucidated. Here, we defined the effects of ZIKV on the developing brain using single cell transcriptomics, histopathology and design-based stereology, diffusion MRI, and neurobehavioral assessments in infant rhesus macaques. ZIKV upregulated interferon-stimulated genes in activated microglia and cell death pathways in neurons and downregulated metabolism and differentiation genes in mature oligodendrocytes. Abnormal micro-organization of the corpus collosum and limbic white matter tracts was seen on diffusion weighted imaging. A curated gene set associated with autism spectrum disorder risk was negatively enriched in inhibitory and excitatory neurons from ZIKV-infected infants, with increased emotional reactivity already evident two weeks following infection. From single cells to organism-level behaviors, these results define the pathways and processes disrupted by early-life ZIKV infection.

Low social status leads to chronic social stress that predicts risk for physical and mental illness, especially when it starts early in life. To examine the longitudinal effects of low social status on the immune system, this study assessed the effects of low social status on developmental secretory patterns of pro- and anti-inflammatory markers under baseline conditions, as well as in response to an immune challenge (lipopolysaccharide (LPS)-induced activation of pro- and anti-inflammatory cytokines) in a translational rhesus monkey model of lifelong social subordination stress. Baseline blood samples were collected in 27 socially housed female rhesus monkeys (13 dominants, DOM, and 14 subordinates, SUB) during infancy (6 months), the juvenile pre-pubertal period (16 months), and adulthood (9–10 years) to examine the longitudinal effects of social status on inflammatory markers in unstimulated versus LPS-stimulated conditions mimicking exposure to bacterial infection. Basal levels of the stress hormone cortisol in blood were measured to examine associations between inflammation and activity of the hypothalamic–pituitary–adrenal (HPA) axis throughout the life span. Basal peripheral levels of inflammatory markers (e.g., IL-6) increased across development in both SUB and DOM animals with no significant differences. Basal cortisol levels were significantly higher in infancy as compared to adulthood, but no significant effects of social rank were detected. However, in adulthood, SUB animals showed a cytokine-specific immune response to ex vivo LPS stimulation with significantly higher secretions of IL-1β, IL-2, and IL-10 compared to DOM animals, whereas IL-8 response to LPS was lower in SUB animals than in DOMs. This cytokine-specific response to an immune challenge that mimics bacterial infection could reflect dysregulated immune cells that may have short-term adaptation, but at the cost of longer-term risks for low-grade chronic inflammation and accelerated immune aging for socially subordinate female macaques.

Although most SARS-CoV-2 infections result in mild or moderate symptoms not requiring hospitalization, many patients experience persistent symptoms after their initial recovery, a condition termed Post-Acute Sequelae of SARS-CoV-2 infection (PASC). The underlying pathogenesis behind infection associated chronic illnesses, such as PASC, are poorly understood, thus critically limiting the development of therapeutics to prevent or alleviate symptoms. The current study examined the neurocognitive impact of SARS-CoV-2 induced inflammation in a nonhuman primate model. Ten adult rhesus macaques (5 female, 5 male) were monitored before, during, and after recovery from a mild COVID-19 illness (SARS-CoV-2 strain 2019-noCoV/USA-WA1/2020). Macaques exhibited persistent alterations in taste and smell, as well as decreased cognitive flexibility up to 3 months post-infection. Female macaques experienced sleep disturbances, greater stress and poorer autonomic function months after SARS-CoV-2 infection. Importantly, the development of these neurocognitive changes were associated with acute cytokine response to infection and increased microglia activation in brain tissue at 4 months post-infection. These findings suggest a causative link between the inflammatory response to mild COVID-19 symptoms and persistent neurocognitive changes associated with PASC and provide rationale for therapeutic strategies aimed at reducing acute inflammatory responses to the virus.

This study examined the long-term effects of low social status on reproductive success and seasonal changes in reproductive and stress hormones of adult female rhesus macaques. Rhesus are a matriarchal, matrilineal species that form hierarchical social hierarchies maintained by aggression. Thus, animals in the bottom of the hierarchy (low social status: subordinate) experience high levels of aggression from those in higher social ranks and therefore must remain vigilant. Social subordination generates chronic psychosocial stress and could negatively impact reproductive function. Twenty-seven adult female rhesus monkeys (13 dominant -DOM-, 14 subordinate -SUB-; 8-11 years old) were studied for stress neuroendocrine function -measuring basal plasma levels of cortisol-, as well as for reproductive endocrine function -measuring basal levels of estradiol (E2). In addition, we examined the reproductive success rates of these females (defined as number of live births/years with male access), their success rates raising infants that survived to 1 year, and the characteristics and effectiveness of their maternal care. Our findings show significantly lower reproductive success rates in SUB than DOM females, blunted E2 seasonal changes, driven by higher E2 levels in the anovulatory season and more attentive maternal care of offspring early in life than dominant females. Age at first birth was negatively associated with infant survival rate across ranks. Interestingly, higher levels of reproductive hormones (E2) during the anovulatory season predicted lower reproductive success, although the effect was driven by animals lactating at that point. Overall, these findings suggest that subordinate female macaques show a phenotype consistent with impaired reproductive function. Simple Summary: This study examined the long-term effects of low social status on reproductive success and seasonality of reproductive and stress physiology of female rhesus monkeys. The despotic rhesus social hierarchy is matrilineal and maintained by aggression. Males leave their natal group in bachelor groups around puberty, but females remain, so social status of group members is passed down the female line. Rhesus with low social status (subordinate) experience significantly more aggression and harassment than their higher-ranking counter parts (dominant). This makes rhesus macaques an ideal model for studying chronic psychosocial stress and its long-term effects. Our findings show significantly lower reproductive success rates (number of live births based on access to males; lower infant survival rates) in subordinate than dominant females. Subordinate females also show blunted seasonal changes of the gonadal hormone estradiol (E2), driven by higher E2 levels in the anovulatory season than dominant animals, as well as more attentive maternal care of offspring early in life than dominant animals. Age at first birth was negatively associated with infant survival rate across ranks. Interestingly, higher levels of reproductive hormones (E2) during the anovulatory season were associated with lower reproductive success, although the effect was driven by animals lactating at that point. Overall, these findings suggest that female macaques with lower social status show a phenotype consistent with impaired reproductive function, though the biological mechanisms involved need to be further explored.

A substantial body of literature has demonstrated a consistent link between psychosocial stress and obesity in children, particularly in those from low socioeconomic backgrounds. Despite evidence indicating a complex interplay between stress, diet and obesity, there is a limited understanding of the specific versus potentially synergistic effects of obesity and stress on brain structural and functional development. This study investigates the developmental and long-term brain structural alterations resulting from exposure to chronic social stress due to low (subordinate -SUB-) social status and postnatal obesogenic diets. Forty-one female rhesus macaques (Dominants -DOM-, n=21; Subordinates -SUB-, n=20) were assigned to either only low-calorie diet (LCD) or to both high-calorie diet (HCD) and LCD (Choice diet) from birth through the juvenile period. After menarche, all subjects were maintained on a LCD-only diet through adulthood. Twenty-seven animals (DOM: n=13, SUB: n=14) were studied again in adulthood to investigate the long-term effects of early diet and social rank on brain structure. Cumulative Kcal consumption was measured from birth through 16 months and body weights were measured at all time points. Overall, the findings show specific effects of obesogenic diet and psychosocial stress on cortical and corticolimbic brain regions. Animals with access to the obesogenic diet had larger overall brain size (measured as intracranial volume -ICV-) and larger overall volumes of prefrontal cortex, insula, superior temporal sulcus (defined as temporo-parieto-occipital area rostral and caudal regions (TPOr and TPOc)) than those in the low-calorie diet. Most of these regional diet effects, except for the insula, were driven by general effects of the diet on brain size. The diet effects were lost when adding the adult data to the longitudinal analysis, suggesting transient effects of obesogenic diets while the animals were consuming it, but not long-term, persistent effects. These findings highlight the potential of brain rescue mechanisms that could offset lasting developmental effects of early-life obesogenic diet consumption. With respect to social rank, SUB exhibited larger volumes in brain regions related to social cognition and emotional processing than DOM animals. When the adult data was added to the longitudinal analysis, the effects of social rank were prominent in the hippocampus, superior temporal sulcus, temporo-parieto-occipital rostral region, and the temporal auditory cortices after ICV data correction, suggesting long-term, persistent and cumulative effects of these social experiences, in contrast to the transient diet effects.

Because of their close relationship with humans, non-human apes (chimpanzees, bonobos, gorillas, orangutans, and gibbons, including siamangs) are of great scientific interest. The goal of understanding their complex behavior would be greatly advanced by the ability to perform video-based pose tracking. Tracking, however, requires high-quality annotated datasets of ape photographs. Here we present OpenApePose, a new public dataset of 71,868 photographs, annotated with 16 body landmarks of six ape species in naturalistic contexts. We show that a standard deep net (HRNet-W48) trained on ape photos can reliably track out-of-sample ape photos better than networks trained on monkeys (specifically, the OpenMonkeyPose dataset) and on humans (COCO) can. This trained network can track apes almost as well as the other networks can track their respective taxa, and models trained without one of the six ape species can track the held-out species better than the monkey and human models can. Ultimately, the results of our analyses highlight the importance of large, specialized databases for animal tracking systems and confirm the utility of our new ape database.