Nonhuman Primate Studies Research Articles

Male-philopatric nonhuman primates and their potential role in understanding the evolution of human sociality.

In most primate species, males transfer out of their natal groups, resulting in groups of unrelated males. However, in a few species, including humans, males remain in their groups and form life-long associations with each other. This pattern of male philopatry is linked with cooperative male behaviors, including border patrols and predator defense. Because females in male-philopatric species form weaker kin networks with each other than in female-philopatric species, they are expected to evolve counter-strategies to male sexual coercion that are relatively independent of support from other females. Studies of male-philopatric nonhuman primates can provide insight into the evolutionary basis of prosocial behaviors, cooperation, and group action in humans and offer comparative models for understanding the sociality of other hominin species. This review will discuss patterns of dispersal and philopatry across primates, explore the resulting male and female behaviors, and argue that male-philopatric nonhuman primate species offer insight into the social and sexual dynamics of hominins throughout evolution.

Development and assessment of a stair ascension challenge as a measure of aging and physical function in nonhuman primates.

Nonhuman primates (NHPs) are valuable models for studying healthspan, including frailty development. Frailty metrics in people centers on functional measures, including usual gait speed which can be predictive of all-cause mortality. This concept that physical competencies are able to prognosticate an individual's health trajectory over chronologic aging is well-accepted and has led to refinements in how physical function is evaluated, and include measures of strength and power along with walking speed. NHP studies of aging require evaluation of physical function, which can be difficult in field and research settings. We compared stair climb velocity to usual walking speed in 28 peri-geriatric to geriatric NHPs, as incorporating a climbing obstacle integrates multiple components of physical function: isolated leg and back strength, proprioception, balance, and range of motion. We find that stair climbing speed was reliable between observers, and whether timing was in-person take from video capture. The stair climb rates were 50% more associated with chronological age than walking speed (R = -0.68 vs. -0.45) and only stair climbing speeds were retained as predictive of age when walking speed and bodyweight were included in multivariate models (overall R2 = 0.44; p < 0.0001). When comparing young (10-16 years) versus geriatric (16-29 years) stair climbing speed was significantly different (p < 0.001), while walking speeds only tended to be slower (p = 0.12) suggesting that the additional challenge of a stair climb better unmasks subclinical frailty development that usual walking speed.

Pre-saccadic Neural Enhancements in Marmoset Area MT.

Each time we make an eye movement, attention moves before the eyes, resulting in a perceptual enhancement at the target. Recent psychophysical studies suggest that this pre-saccadic attention enhances the visual features at the saccade target, whereas covert attention causes only spatially selective enhancements. While previous nonhuman primate studies have found that pre-saccadic attention does enhance neural responses spatially, no studies have tested whether changes in neural tuning reflect an automatic feature enhancement. Here we examined pre-saccadic attention using a saccade foraging task developed for marmoset monkeys (one male and one female). We recorded from neurons in the middle temporal area with peripheral receptive fields that contained a motion stimulus, which would either be the target of a saccade or a distracter as a saccade was made to another location. We established that marmosets, like macaques, show enhanced pre-saccadic neural responses for saccades toward the receptive field, including increases in firing rate and motion information. We then examined if the specific changes in neural tuning might support feature enhancements for the target. Neurons exhibited diverse changes in tuning but predominantly showed additive and multiplicative increases that were uniformly applied across motion directions. These findings confirm that marmoset monkeys, like macaques, exhibit pre-saccadic neural enhancements during saccade foraging tasks with minimal training requirements. However, at the level of individual neurons, the lack of feature-tuned enhancements is similar to neural effects reported during covert spatial attention.

XTX301, a Tumor-Activated Interleukin-12 Has the Potential to Widen the Therapeutic Index of IL12 Treatment for Solid Tumors as Evidenced by Preclinical Studies.

IL12 is a proinflammatory cytokine, that has shown promising antitumor activity in humans by promoting the recruitment and activation of immune cells in tumors. However, the systemic administration of IL12 has been accompanied by considerable toxicity, prompting interest in researching alternatives to drive preferential IL12 bioactivity in the tumor. Here, we have generated XTX301, a tumor-activated IL12 linked to the human Fc protein via a protease cleavable linker that is pharmacologically inactivated by an IL12 receptor subunit beta 2 masking domain. In vitro characterization demonstrates multiple matrix metalloproteases, as well as human primary tumors cultured as cell suspensions, can effectively activate XTX301. Intravenous administration of a mouse surrogate mXTX301 demonstrated significant tumor growth inhibition (TGI) in inflamed and non-inflamed mouse models without causing systemic toxicities. The superiority of mXTX301 in mediating TGI compared with non-activatable control molecules and the greater percentage of active mXTX301 in tumors versus other organs further confirms activation by the tumor microenvironment-associated proteases in vivo. Pharmacodynamic characterization shows tumor selective increases in inflammation and upregulation of immune-related genes involved in IFNγ cell signaling, antigen processing, presentation, and adaptive immune response. XTX301 was tolerated following four repeat doses up to 2.0 mg/kg in a nonhuman primate study; XTX301 exposures were substantially higher than those at the minimally efficacious dose in mice. Thus, XTX301 has the potential to achieve potent antitumor activity while widening the therapeutic index of IL12 treatment and is currently being evaluated in a phase I clinical trial.

EX103, a Novel CD20xCD3 Bispecific Antibody, Showed a Favorable Safety and Potent Single-Agent Antitumor Activity in Heavily Pretreated Relapsed/Refractory Patients with B-Cell Non-Hodgkin Lymphoma

Introduction Non-Hodgkin lymphoma (NHL) is one of the most common cancers in the United States, and relapsed or refractory (R/R) B cell NHL had a poor prognosis. In recent years, T cell engaging bispecific antibody (TCB) emerged as a promising therapy. Nevertheless, severe cytokine release syndrome (CRS) remains to be a significant challenge in TCB treatment. To overcome this issue, we designed a new CD20xCD3 bispecific antibody (EX103) with a lower affinity to CD3. In the non-human primate tox study, EX103 induced much lower IL-6 release. Preliminary data from dose escalation part of Phase I clinical study demonstrates that EX103 has an encouraging safety and robust single-agent antitumor activity trend, even at low doses, in heavily pretreated R/R B-NHL patients. Method The dose-escalation part (8 dose cohorts, ranging from 1.2 to 36 mg) of this Phase I, multicenter, single-arm, open-label clinical trial has enrolled R/R CD20+ B-cell non-Hodgkin lymphoma subjects at 4 study sites in China. Objectives include safety, dose finding (RP2D), and antitumor activity. Eligible patients in each cohort received intravenous(iv) step-up doses of EX103 (with 1 priming dose and 2 intermediate doses followed by 1 target dose of EX103) administered in a 28-day dose limiting toxicity (DLT) observation period, and then received a target dose every 2 weeks for up to 12 cycles until disease progression or unacceptable toxicity. Response rates reported are based on the Lugano criteria (2014). Results As of June 2023, 5 cohorts (target dose from 1.2 to 18 mg) of the dose-escalation were completed. Among 13 evaluable patients , 9 of them are aggressive B-NHL (5 Diffuse large B-cell lymphoma (DLBCL), 3 Follicular lymphoma (FL) grade 3B, and 1 Mantle cell lymphoma (MCL)), 2 of them are indolent B-NHL (1 FL grade 1-3A, 1 Marginal zone lymphoma (MZL)), and 2 of them are Chronic lymphocytic leukemia (CLL). No DLT was observed, and the maximum tolerated dose (MTD) was not reached. The most common adverse events (AEs) were CRS, pyrexia, neutropenia, thrombocytopenia. All CRS were grade (Gr) 1-2, no Gr 3 or higher CRS. Most CRS events occurred in first or second treatment cycle, and all CRS related clinical symptoms were resolved within 48 hours. No Immune effector cell-associated neurotoxicity syndrome (ICANS) or other clinically significant neurologic AEs were reported. Among those patients, the median age was 51 years (range 43-66) and median number of prior lines of treatment was 5 (range 2-8). The preliminary Disease Control Rate (DCR) is 84.6% (11/13). Among 9 aggressive NHL patients, the overall response rate (ORR) was 67.7 % (6/9), including 3 DLBCL patients (1 each in 6 or 12 or 18 mg cohorts) and 1 MCL patient (in 3 mg cohort) achieving CR, and 2 grade 3B FL patients achieving PR (1 each in 6 or 18 mg cohorts). Both indolent NHL patients (1 FL (Grade 1-3A) and 1 MZL in 12 mg cohort) achieved PR and the preliminary ORR for indolent NHL was 100.0 % (2/2). Of 2 CLL patients, 1 achieved SD (3mg cohort). It is worth mentioning that two of the patients who failed prior CAR-T treatment had achieved PR after received 6-14 week treatment of EX103. Both patients are still under EX103 treatment. Conclusions Although this study has a limited number of subjects so far and the findings are preliminary, the available dose-escalation data demonstrate that single-agent EX103, even at low doses (3 or 6 mg), exhibits remarkable antitumor activity and favorable safety. Furthermore, EX103 demonstrates promising efficacy in heavily pretreated patients with R/R B-NHL, including some who have previously failed CAR-T treatment. The safety and efficacy of EX103 will be further evaluated in an ongoing clinical study.

1355. The SARS-CoV-2 Monoclonal Antibody AZD3152 Potently Neutralizes Historical and Emerging Variants and is Being Developed for the Prevention and Treatment of COVID-19 in High-risk Individuals

Abstract Background EVUSHELD was developed for the prevention and treatment of mild-to-moderate COVID-19 for high-risk individuals. However, the SARS-CoV-2 virus continues to evolve in the presence of natural- and vaccine-acquired immunity, escaping previously authorized antibody therapies such as bebtelovimab and EVUSHELD. AZD3152 was selected to neutralize all known SARS-CoV-2 variants of concern and is being developed to provide immunocompromised individuals with continued protection against SARS-CoV-2. Methods Structural analyses were performed to map the AZD3152 binding site. Neutralization assays were employed to determine the potency of AZD3152 across a panel of historical and emerging SARS-CoV-2 variants. Hamsters were prophylactically administered 6.7-60 mg/kg AZD3152 or a control antibody, then challenged intranasally with 6x103 PFU WA-1 SARS-CoV-2, then monitored for weight loss; lung viral load and pathology were evaluated at days 3 and 7. A 3 week GLP repeat IM and IV dose toxicity study in nonhuman primates (NHP) was performed. Results AZD3152 binds to a conserved epitope on the spike receptor binding domain and blocks ACE2 binding. AZD3152 potently neutralizes authentic viral variants (EC50 range, 8.3 to 110.9 ng/mL) and SARS-CoV-2 pseudoviruses (EC50 range of 3.2 to 25.0 ng/mL), including XBB.1.5. Prophylactic administration of AZD3152 conferred dose-dependent protection to hamsters following challenge. Even at a suboptimal dose of 6.7 mg/kg, &amp;lt; 5% weight loss and 2 logs reduction in lung viral subgenomic RNA were observed. AZD3152 was not associated with any adverse findings in NHP and the no observed-adverse-effect-level was the highest dose tested (150 mg/kg). Toxicokinetics demonstrated similar systemic exposure following IM and IV dosing with bioavailability of 94.9% and half-life range of 15.2-26.5 days by IM. Conclusion These results demonstrate that AZD3152 binds a conserved epitope resulting in broad neutralization of SARS-CoV-2 variants, protects hamsters from disease, and has a favorable safety profile in NHP. Thus, AZD3152 may serve as a next-generation antibody for the prevention and treatment of COVID-19. Disclosures Joseph R Francica, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Yingyun Cai, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Seme Diallo, MS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Kim Rosenthal, MS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Kuishu Ren, BS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Daniel J. Flores, MS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Andrew Dippel, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Yuling Wu, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Xiaoru Chen, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Erin Cantu, BS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Rakesh Choudhary, MS, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Michal Sulikowski, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Hibret Adissu, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Nydia van Dyk, MSc, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Vaheh Oganesyan, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Saravanan Rajan, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Patricia C. Ryan, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Yueh-Ming Loo, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Taylor Cohen, PhD, AstraZeneca: Employement|AstraZeneca: Stocks/Bonds Mark T. Esser, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds Wade Blair, PhD, AstraZeneca: Employee|AstraZeneca: Stocks/Bonds

The PREMISE database of 20 Macaca fascicularis PET/MRI brain images available for research

Non-human primate studies are unique in translational research, especially in neurosciences where neuroimaging approaches are the preferred methods used for cross-species comparative neurosciences. In this regard, neuroimaging database development and sharing are encouraged to increase the number of subjects available to the community, while limiting the number of animals used in research. Here we present a simultaneous positron emission tomography (PET)/magnetic resonance (MR) dataset of 20 Macaca fascicularis images structured according to the Brain Imaging Data Structure standards. This database contains multiple MR imaging sequences (anatomical, diffusion and perfusion imaging notably), as well as PET perfusion and inflammation imaging using respectively [15O]H2O and [11C]PK11195 radiotracers. We describe the pipeline method to assemble baseline data from various cohorts and qualitatively assess all the data using signal-to-noise and contrast-to-noise ratios as well as the median of intensity and the pseudo-noise-equivalent-count rate (dynamic and at maximum) for PET data. Our study provides a detailed example for quality control integration in preclinical and translational PET/MR studies with the aim of increasing reproducibility. The PREMISE database is stored and available through the PRIME-DE consortium repository.

Atypical Ebola Virus Disease in a Rhesus Macaque.

Ebola virus (EBOV)-Makona infected more than 30 000 people from 2013 to 2016 in West Africa, among them many health care workers including foreign nationals. Most of the infected foreign nationals were evacuated and treated in their respective home countries, resulting in detailed reports of the acute disease following EBOV infection as well as descriptions of symptoms now known as post-Ebola syndrome, which occurred months after the infection. Symptoms associated with this syndrome include uveitis and neurological manifestations. In 1 of our EBOV-Makona nonhuman primate (NHP) studies, 1 NHP was euthanized on day 28 after infection having completely recovered from the acute disease. During convalescence, this NHP developed neurological signs and acute respiratory distress requiring euthanasia. The organ tropism had changed with high virus titers in lungs, brain, eye, and reproductive organs but no virus in the typical target organs for acute EBOV infection. This in part reflects sequelae described for EBOV survivors albeit developing quicker after recovery from acute disease.

DDEL-01. UTILIZING SENSOR ARRAYS FOR INTRACRANIAL PRESSURE (ICP) RESPONSE TO CEREBROSPINAL FLUID (CSF) DRUG ADMINISTRATION, AND POTENTIAL IMPLICATIONS FOR PERSONALIZED CARE IN CNS METASTASES PATIENTS

Abstract BACKGROUND Patients with leptomeningeal carcinomatosis (LC) may have elevated intracranial pressure (ICP) due to LC cancer cells having the potential to obstruct the arachnoid granulations.,Given that LC treatment may involve intrathecal (IT) drug delivery, monitoring ICP may be important for safe IT drug delivery. The EnClear device is a novel CNS drug delivery device with both intracranial and intralumbar CSF access and single-use sensing arrays that measure ICP in these dual locations. METHODS This is a non-human primate (NHP) study on three healthy NHP subjects undergoing IT gene therapy via intracerebroventricular (ICV). The sensor arrays measured ICP before, during, and after ICV infusion in both intracranial and lumbar locations. Our goal was to compare individual subject pressure response to drug administration as well as to compare lumbar and cranial pressure waveforms for concordance. Pressure response was quantified as change in pressure (ΔP) following volume (ΔV) administration, known as intracranial elastance (ΔP/ΔV). RESULTS Significant correlations were observed between ventricular and lumbar ICP waveforms with an average of 0.88 correlation coefficient. Pressure measurements between subjects demonstrated variable response to identical infusion volumes, with maximum pressures ranging from 20 mmHg to 40 mmHg. Intracranial elastance was calculated for each subject during infusions and resulted in a range of 12 to 36 mmHg/mL, a 3-fold difference in elastance between subjects. CONCLUSION In healthy NHPs, changes to cranial volume and pressure response can be measured in the lumbar space with good correlation between the two measurement locations. Despite this consistency between these two locations on the same subject, intersubject variability was seen despite identical drug administration. Pressure waveform sensing systems can be incorporated in the future to enable clinicians to understand individual patient brain compliance and leverage this knowledge for personalized drug delivery, particularly in patients with LC.

Abstract 17013: CTX320: An Investigational in vivo CRISPR-Based Therapy Efficiently and Durably Reduces Lipoprotein (a) Levels in Non-Human Primates After a Single Dose

Background: Genetic and epidemiological studies have identified elevated levels of lipoprotein (a) (Lp(a)) as a direct cause of atherosclerosis and related diseases. CTX320™ is an investigational in vivo CRISPR/Cas9 gene editing therapy designed to knock out the apolipoprotein (a) component of Lp(a) in the liver. CTX320 contains Cas9 mRNA and guide RNA (gRNA) formulated for efficient encapsulation into LNPs for in vivo administration . Here we assessed the efficacy, safety, and durability of CTX320 in primary human cells and non-human primates (NHPs). Methods: For in vitro studies, primary human hepatocytes were plated and dosed with CTX320 one day later. Cells were harvested after three days and analyzed via Sanger and next-generation sequencing. For NHP studies, cynomolgus monkeys were dosed with either vehicle control or CTX320 at doses ranging from 0.5 to 3 mg/kg. Baseline levels of plasma Lp(a) were established via ELISA prior to dosing and plasma Lp(a) levels were measured at multiple intervals after dosing until the end of each study. Results: In primary human hepatocytes, potent, dose-dependent editing of up to &gt;80% was observed with CTX320. In NHPs, dose-dependent editing in the liver of ~10%, ~45%, and ~65% at the 0.5, 1.5, and 3 mg/kg doses, respectively, was observed after treatment with CTX320. Plasma Lp(a) levels were reduced by ~20%, ~80%, and ~90% from baseline in each of these respective groups. These reduced Lp(a) levels were attained by Day 15 and lasted for the duration of the study (Day 84). As is commonly observed with LNP delivery, transient elevation in liver enzymes was observed and resolved within 14 days without intervention. In a separate durability study in NHPs, a single infusion of CTX320 at 2 mg/kg led to significant and durable decreases in plasma Lp(a) levels. By Day 14, plasma Lp(a) levels had decreased by an average of 94% from baseline, which persisted through Day 224. The study is ongoing. Conclusion: CTX320 was well-tolerated in NHPs and resulted in high levels of editing in the liver that led to long-lasting reduction in plasma Lp(a). This data suggests CTX320 could be used to reduce plasma Lp(a) levels in humans.

Abstract 16908: CTX310: An Investigational in vivo CRISPR-Based Therapy Efficiently and Durably Reduces ANGPTL3 Protein and Triglyceride Levels in Non-Human Primates After a Single Dose

Background: Angiopoietin-like 3 (ANGPTL3) is a key regulator of lipid metabolism. In humans, naturally occurring loss-of-function variants in ANGPTL3 are associated with reduced levels of serum lipids and reduced risk of atherosclerotic cardiovascular disease. CTX310™ is an investigational in vivo CRISPR/Cas9 gene editing therapy designed to knock out hepatic expression of ANGPTL3. CTX310 consists of Cas9 mRNA and guide RNA (gRNA) targeting ANGPTL3 encapsulated into lipid nanoparticles (LNPs). Here we assessed the efficacy, safety, and durability of CTX310 in primary human cells, mice, and non-human primates (NHPs). Methods: CTX310 was evaluated in vitro in primary human hepatocytes (PHHs), in vivo in wildtype C57BL/6J and LDLR-/- mice using a mouse surrogate gRNA, and in vivo in NHPs where the human target sequence is conserved. For the NHP studies, cynomolgus monkeys were infused with a single dose of CTX310 at doses ranging from 0.5 to 3.0 mg/kg to evaluate efficacy (N=32) and durability (N=8). Results: In PHHs, &gt;90% on-target editing was achieved with CTX310, leading to a &gt;90% reduction in ANGPTL3 production. Comprehensive genomic assessment indicated no sign of unintended genomic changes introduced by CTX310. In wildtype mice administered LNPs containing a mouse surrogate gRNA along with the same Cas9 mRNA and lipid components as CTX310, ~50% liver editing yielded a &gt;95% reduction in plasma ANGPTL3 protein and ~40% reduction in triglyceride levels, sustained up to nine months post-dosing. Similar levels of editing and efficacy were observed in LDLR-/- mice, suggesting an LDLR-independent uptake mechanism.In NHPs, dose-dependent editing of ANGPTL3 in the liver of up to 71% was observed, resulting in reduced levels of plasma ANGPTL3 protein (up to 86%) and triglycerides (up to 64%). Reductions in ANGPTL3 protein and triglycerides were durable past 32 weeks. As is commonly observed with LNP delivery, transient elevation of liver enzymes was observed and resolved within 14 days without intervention. Conclusion: CTX310 was well-tolerated in NHPs and led to significant and durable reductions in circulating ANGPTL3 and triglycerides. This data suggests that CTX310 could be used to treat dyslipidemias in humans.

Potent in Vitro and In Vivo Efficacy of BYON4413, a Duba-Based Antibody-Drug Conjugate Targeting CD123 in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) and myelodysplasia (MDS) result from a differentiation impairment driving an accumulation of immature myeloid cells in the bone marrow and peripheral blood. A widely reported feature of these neoplastic myeloid cells is an increased cell surface expression of CD123, the IL3 receptor α subunit. This observation has established CD123 as an attractive target for precision therapy. Here, we describe BYON4413, a novel antibody-drug conjugate (ADC) that binds with high affinity to CD123. BYON4413 comprises a humanized IgG1 antibody directed at CD123 that is site-specifically conjugated to Byondis' proprietary duocarmazine linker-drug (LD) technology, ByonZine® and ByonShieLD®. This LD, when cleaved upon internalization and lysosomal routing, releases a potent duocarmycin payload that alkylates DNA, generating damage that results in replication stress and cell death. In vitro studies with AML cell lines demonstrate that BYON4413 is highly effective in eradicating CD123-positive cells while having little impact on CD123-negative cells. Similar results are observed when we test BYON4413 on AML patient-derived BMMCs/PBMCs in ex vivo assays (n=50), indicating that the specificity of BYON4413 cytotoxicity is largely limited to CD123-positive cells. Ex vivo experiments also reveal a stronger potency of BYON4413 in AML patient-derived blasts compared to healthy CD34 + hematopoietic stem/progenitor cells. In vivo PK/PD studies demonstrate that BYON4413 is remarkably efficient at reducing the tumor burden in multiple AML patient- and cell line-derived xenograft models. Studies in non-human primates suggest that BYON4413 has a favorable toxicity profile and a high maximum tolerable dose, features that should enable combination strategies with other oncolytics. In sum, BYON4413 shows great potential to be an effective targeted therapy against AML, MDS, and other CD123 + hematological malignancies such as blastic plasmacytoid dendritic cell neoplasm (BPDCN). Readied with these promising pre-clinical results, we have designed a first-in-human dose-escalation and expansion trial enrolling AML and high-risk MDS patients scheduled to begin in Q12024.

Translating an HPFH-Mechanism into Oral Small Molecule Therapy for Beta-Hemoglobinopathies: Clinical Proof-of-Principle

Introduction: Hereditary persistence of fetal hemoglobin (HPFH) down-modulates co-inherited sickle cell disease (SCD) severity, encouraging characterization of HPFH-mechanisms for interventional reprise. One HPFH mechanism is polymorphisms in DNA methyltransferase 1( DNMT1) that decrease DNMT1 protein stability (Gong et al, Blood 2021), agreeing with biochemical observations that DNMT1 mediates repression of fetal hemoglobin (HbF) genes by BCL11A. Here we describe translation of this HPFH-mechanism into oral therapy for SCD patients at high-risk for early mortality (Steinberg et al, JAMA 2004) despite standard-treatments. Methods and Results: The small molecule decitabine (Dec) contains a pyrimidine ring modification that binds and depletes DNMT1 and a natural deoxyribose that incorporates into DNA without terminating chain synthesis: minimum biologically effective doses of Dec, to deplete DNMT1 without cytotoxicity, can thus be found (reviewed in Zavras et al, Clin Ca Res, 2021). Other key properties of Dec are tropism to hematopoietic precursors, driven by high expression in these cells of deoxycytidine kinase that phosphorylates Dec, and rapid catabolism in vivo by cytidine deaminase (CDA), that severely restricts Dec bioavailability and half-life. We therefore combined Dec with a CDA-inhibitor tetrahydrouridine (THU): dose and schedule of THU/Dec that depleted DNMT1 without cytotoxicity to hematopoietic precursors in vivo were identified in non-human primate studies and Phase 1 clinical trials (Molokie et al, PLoS Med 2017), and here we describe interim results from proof-of-principle study in patients with SCD ( Table 1). Study interventions were oral THU/Dec (~10/0.2 mg/kg) 1X/week with or without oral nicotinamide (vitamin B3) 1 g/day. B3 was studied because it is a direct precursor of NADH, a fundamental antioxidant currency and also a cofactor for epigenetic enzymes that channel hematopoiesis to erythropoiesis vs megakaryopoiesis, to potentially counter an expected side-effect of THU/Dec of increasing platelets. Randomization was to THU/Dec vs B3 for 12 weeks, followed by THU/Dec + B3 for 12 weeks, then option to extend therapy for a further 24 weeks. Standard clinical and laboratory parameters were measured. Six patients enrolled, were randomized equally to THU/Dec or B3, and opted to extend. Dose-limiting toxicities (DLTs), including neutropenia or thrombocytosis, did not occur ( Table 1). In the year preceding study-treatment, 15 vaso-occlusive crises (VOC) requiring hospitalization were documented ( Table 1). By comparison, during 52 weeks on-study (48 weeks on-therapy, 4 weeks follow-up), the grade 3/4 adverse events were VOC hospitalizations x3 (1 during follow-up without therapy, 1 during B3 alone, 1 during B3 + THU/Dec therapy), hyperkalemia x2, and non-cardiac chest pain x1 ( Table 1)(p=0.04, paired t-test 2-sided). THU/Dec dose (7.6/0.15 mg/kg) was below the Phase 1 identified minimum biologically effective dose window (8-12/0.16-0.25 mg/kg, protocol since amended to accommodate high body weights) in one patient (TDN04) who accordingly did not have HbF% or hemoglobin increases ( Fig.1). In the 5 other patients, HbF increases (pre-treatment to maximum) were: 9.4 to 17.3, 5.9 to 11, 3.4 to 9.3, 3.3 to 16.3 and 5.7 to 10 % ( Fig.1). There were corresponding improvements in hemolysis and coagulation pathway parameters (LDH, total bilirubin, D-Dimer), and total hemoglobin increased from 9.9 to 11.5, 8.7 to 10.6, 6.6 to 7.7, 5.7 to 7.1 and 8 to 9.7 g/dL respectively. TDN01 and 06, the two patients with lowest pre-treatment hemoglobin, requested and resumed THU/Dec post-study by Expanded Access. Conclusions: This is the longest-term treatment to date of oral THU/Dec to target DNMT1 in patients with SCD, with or without B3. Subjective and objective improvements were sustained without DLTs in high-risk patients who displayed known negative prediction markers for response to hydroxyurea (HbF% &amp;lt;7.5%, reticulocyte count &amp;lt;300 x10 9/L - Steinberg et al, Blood 1997). The safety and efficacy signals align with scientific target validation data, and together with accessibility, support relevance to SCD patient needs and goals worldwide, bearing in mind major study limitations of single-site enrollment and only 6 patients.

In humans, striato-pallido-thalamic projections are largely segregated by their origin in either the striosome-like or matrix-like compartments

Cortico-striato-thalamo-cortical (CSTC) loops are fundamental organizing units in mammalian brains. CSTCs process limbic, associative, and sensorimotor information in largely separated but interacting networks. CTSC loops pass through paired striatal compartments, striosome (aka patch) and matrix, segregated pools of medium spiny projection neurons with distinct embryologic origins, cortical/subcortical structural connectivity, susceptibility to injury, and roles in behaviors and diseases. Similarly, striatal dopamine modulates activity in striosome and matrix in opposite directions. Routing CSTCs through one compartment may be an anatomical basis for regulating discrete functions. We used differential structural connectivity, identified through probabilistic diffusion tractography, to distinguish the striatal compartments (striosome-like and matrix-like voxels) in living humans. We then mapped compartment-specific projections and quantified structural connectivity between each striatal compartment, the globus pallidus interna (GPi), and 20 thalamic nuclei in 221 healthy adults. We found that striosome-originating and matrix-originating streamlines were segregated within the GPi: striosome-like connectivity was significantly more rostral, ventral, and medial. Striato-pallido-thalamic streamline bundles that were seeded from striosome-like and matrix-like voxels transited spatially distinct portions of the white matter. Matrix-like streamlines were 5.7-fold more likely to reach the GPi, replicating animal tract-tracing studies. Striosome-like connectivity dominated in six thalamic nuclei (anteroventral, central lateral, laterodorsal, lateral posterior, mediodorsal-medial, and medial geniculate). Matrix-like connectivity dominated in seven thalamic nuclei (centromedian, parafascicular, pulvinar-anterior, pulvinar-lateral, ventral lateral-anterior, ventral lateral-posterior, ventral posterolateral). Though we mapped all thalamic nuclei independently, functionally-related nuclei were matched for compartment-level bias. We validated these results with prior thalamostriate tract tracing studies in non-human primates and other species; where reliable data was available, all agreed with our measures of structural connectivity. Matrix-like connectivity was lateralized (left &amp;gt; right hemisphere) in 18 thalamic nuclei, independent of handedness, diffusion protocol, sex, or whether the nucleus was striosome-dominated or matrix-dominated. Compartment-specific biases in striato-pallido-thalamic structural connectivity suggest that routing CSTC loops through striosome-like or matrix-like voxels is a fundamental mechanism for organizing and regulating brain networks. Our MRI-based assessments of striato-thalamic connectivity in humans match and extend the results of prior tract tracing studies in animals. Compartment-level characterization may improve localization of human neuropathologies and improve neurosurgical targeting in the GPi and thalamus.

Intravitreal injection of a rationally designed AAV capsid library in non-human primate identifies variants with enhanced retinal transduction and neutralizing antibody evasion

Adeno-associated virus (AAV) continues to be the gold standard vector for therapeutic gene delivery and has proven especially useful for treating ocular disease. Intravitreal injection (IVtI) is a promising delivery route because it increases accessibility of gene therapies to larger patient populations. However, data from clinical and non-human primate (NHP) studies utilizing currently available capsids indicate that anatomical barriers to AAV and pre-existing neutralizing antibodies can restrict gene expression to levels that are "sub-therapeutic" in a substantial proportion of patients. Here, we performed a combination of directed evolution in NHPs of an AAV2-based capsid library with simultaneous mutations across six surface-exposed variable regions and rational design to identify novel capsid variants with improved retinal transduction following IVtI. Following two rounds of screening in NHP, enriched variants were characterized in intravitreally injected mice and NHPs and shown to have increased transduction relative to AAV2. Lead capsid variant, P2-V1, demonstrated an increased ability to evade neutralizing antibodies in human vitreous samples relative to AAV2 and AAV2.7m8. Taken together, this study further contributed to our understanding of the selective pressures associated with retinal transduction via the vitreous and identified promising novel AAV capsid variants for clinical consideration.

Production and characterization of a chimeric antigen, based on nucleocapsid of SARS-CoV-2 fused to the extracellular domain of human CD154 in HEK-293 cells as a vaccine candidate against COVID-19.

Despite that more than one hundred vaccines against SARS-CoV-2 have been developed and that some of them were evaluated in clinical trials, the latest results revealed that these vaccines still face great challenges. Among the components of the virus, the N-protein constitutes an attractive target for a subunit vaccine because it is the most abundant, highly conserved and immunogenic protein. In the present work, a chimeric protein (N-CD protein) was constructed by the fusion of the N-protein to the extracellular domain of human CD154 as the molecular adjuvant. HEK-293 cells were transduced with lentiviral vector bearing the N-CD gene and polyclonal cell populations were obtained. The N-CD protein was purified from cell culture supernatant and further characterized by several techniques. Immunogenicity studies in mice and non-human primates showed the N-CD protein induced high IgG titers in both models after two doses. Moreover, overall health monitoring of non-human primates demonstrated that animals were healthy during 228 days after first immunization. Data obtained support further investigation in order to develop this chimeric protein as vaccine candidate against COVID-19 and other coronavirus diseases.

Representative measles virus infection requires appropriate airway epithelia culture conditions.

For many years, measles virus (MeV) was assumed to first enter the host via the apical surface of airway epithelial cells and subsequently spread systemically. We and others reported that MeV has an overwhelming preference for entry at the basolateral surface of airway epithelial cells, which led to a fundamental new understanding of how MeV enters a human host. This unexpected observation using well-differentiated primary cultures of airway epithelia from human donors contradicted previous studies using immortalized cultured cells. Here, we show that appropriate differentiation and cell morphology of primary human airway epithelial cells are critical to recapitulate MeV infection patterns and pathogenesis of the in vivo airways. By simply culturing primary cells in media containing serum or passaging primary cultures, erroneous results quickly emerge. These results have broad implications for data interpretation related to respiratory virus infection, spread, and release from human airway epithelial cells.

Early-in-life isoflurane exposure alters resting-state functional connectivity in juvenile non-human primates

BackgroundClinical studies suggest that anaesthesia exposure early in life affects neurobehavioural development. We designed a non-human primate (NHP) study to evaluate cognitive, behavioural, and brain functional and structural alterations after isoflurane exposure during infancy. These NHPs displayed decreased close social behaviour and increased astrogliosis in specific brain regions, most notably in the amygdala. Here we hypothesise that resting-state functional connectivity MRI can detect alterations in connectivity of brain areas that relate to these social behaviours and astrogliosis. MethodsImaging was performed in 2-yr-old NHPs under light anaesthesia, after early-in-life (postnatal days 6–12) exposure to 5 h of isoflurane either one or three times, or to room air. Brain images were segmented into 82 regions of interest; the amygdala and the posterior cingulate cortex were chosen for a seed-based resting-state functional connectivity MRI analysis. ResultsWe found differences between groups in resting-state functional connectivity of the amygdala and the auditory cortices, medial premotor cortex, and posterior cingulate cortex. There were also alterations in resting-state functional connectivity between the posterior cingulate cortex and secondary auditory, polar prefrontal, and temporal cortices, and the anterior insula. Relationships were identified between resting-state functional connectivity alterations and the decrease in close social behaviour and increased astrogliosis. ConclusionsEarly-in-life anaesthesia exposure in NHPs is associated with resting-state functional connectivity alterations of the amygdala and the posterior cingulate cortex with other brain regions, evident at the juvenile age of 2 yr. These changes in resting-state functional connectivity correlate with the decrease in close social behaviour and increased astrogliosis. Using resting-state functional connectivity MRI to study the neuronal underpinnings of early-in-life anaesthesia-induced behavioural alterations could facilitate development of a biomarker for anaesthesia-induced developmental neurotoxicity.

Development of a specific MPXV antigen detection immunodiagnostic assay.

Human monkeypox (mpox) has recently become a global public health emergency; however, assays that detect mpox infection are not widely available, largely due to cross-reactivity within the Orthopoxvirus genus. Immunoassay development was largely confined to researchers who focus on biothreats and endemic areas (Central and West Africa) until the 2022 outbreak. As was noted in the COVID-19 pandemic, antigen detection assays, integrated with molecular assays, are necessary to help curb the spread of disease. Antigen-detecting immunoassays offer the advantage of providing results ranging from within min to h and in lateral flow formats; they can be deployed for point-of-care, home, or field use. This study reports the development of an mpox-specific antigen detection immunoassay developed on a multiplexed, magnetic-bead-based platform utilizing reagents from all research sectors (commercial, academic, and governmental). Two semi-quantitative assays were developed in parallel and standardized with infectious mpox virus (MPXV) cell culture fluid and MPXV-positive non-human primate (NHP) sera samples. These assays could detect viral antigens in serum, were highly specific toward MPXV as compared to other infectious orthopoxviruses (vaccinia virus, cowpox virus, and camelpox virus), and exhibited a correlation with quantitative PCR results from an NHP study. Access to a toolbox of assays for mpox detection will be key for identifying cases and ensuring proper treatment, as MPXV is currently a global traveler.

A Novel Brain PET Radiotracer for Imaging Alpha Synuclein Fibrils in Multiple System Atrophy.

Abnormal α-synuclein (α-syn) aggregation characterizes α-synucleinopathies, including Parkinson's disease (PD) and multiple system atrophy (MSA). However, no suitable positron emission tomography (PET) radiotracer for imaging α-syn in PD and MSA exists currently. Our structure-activity relationship studies identified 4-methoxy-N-(4-(3-(pyridin-2-yl)-3,8-diazabicyclo[3.2.1]octan-8-yl)phenyl)benzamide (4i) as a PET radiotracer candidate for imaging α-syn. In vitro assays revealed high binding of 4i to recombinant α-syn fibrils (inhibition constant (Ki) = 6.1 nM) and low affinity for amyloid beta (Aβ) fibrils in Alzheimer's disease (AD) homogenates. However, [3H]4i also exhibited high specific binding to AD, progressive supranuclear palsy, and corticobasal degeneration tissues as well as PD and MSA tissues, suggesting notable affinity to tau. Nevertheless, the specific binding to pathologic α-syn aggregates in MSA post-mortem brain tissues was significantly higher than in PD tissues. This finding demonstrated the potential use of [11C]4i as a PET tracer for imaging α-syn in MSA patients. Nonhuman primate PET studies confirmed good brain uptake and rapid washout for [11C]4i.