Restoring striatal dopamine synthesis is a promising gene therapy strategy for Parkinson's disease. Previous adeno-associated virus-mediated aromatic L-amino acid decarboxylase (AADC) monotherapies remain dependent on exogenous levodopa, whereas multigene delivery is constrained by strict adeno-associated virus packaging limits. A 'dual approach' targeting the two rate-limiting enzymes, tyrosine hydroxylase (TH) and AADC, offers the potential for autonomous dopamine synthesis. We report the 12-month primary safety and tolerability outcomes of a multicenter, open-label, dose-escalation, phase 1 trial evaluating BBM-P002, a new adeno-associated virus vector-AAVT42-codelivering constitutively active TH and AADC. Ten participants with moderate-to-advanced Parkinson's disease were enrolled and received bilateral intraputaminal infusions across doses of 4.0 × 1011 vg (Cohort 1; n = 1), 6.0 × 1011 vg (Cohort 2; n = 2), 1.0 × 1012 vg (Cohort 3; n = 2) and 1.2 × 1012 vg (Cohort 4; n = 5). The trial achieved its primary outcome, as BBM-P002 demonstrated a favorable safety and tolerability profile within 12 months post-treatment. No dose-limiting toxicities or drug-related serious adverse events occurred. A total of 23 adverse events were reported, all judged unrelated to BBM-P002 and primarily mild and transient. Systemic toxicity and clinically meaningful immunogenicity were absent. In conclusion, intraputaminal delivery of BBM-P002 was safe and well tolerated in this phase 1 trial, supporting continued clinical development. ClinicalTrials.gov registration: NCT05822739 .

Glucagon-like peptide-1 (GLP-1) is a key incretin hormone rapidly degraded by circulating proteases such as DPP-4. The metabolism of GLP-1 by other proteases, particularly tissue-resident proteases, remains largely unexplored. Here, we identify insulin-degrading enzyme (IDE) as a previously unknown GLP-1-degrading protease with two cleavage sites. We show that IDE-mediated degradation of GLP-1, but not insulin, represents a major mechanism regulating glucose control. To resist IDE, we engineered GLP-1 and Semaglutide with D-amino acid substitutions at these sites. These peptides exhibit enhanced stability in plasma, liver and intestinal secretomes, peritoneal fluid, and central nervous system (CNS). D-Ser 18 -Semaglutide shows prolonged plasma retention and sustained glucose-lowering effects in mice. Moreover, IDE knockdown and intracerebral injection of D-Ser 18 -Semaglutide confirm IDE’s physiological role in GLP-1 degradation, particularly in the CNS. These findings reveal a previously unidentified regulatory mechanism of GLP-1 metabolism and provide a strategy for designing long-acting agonists with improved metabolic and CNS therapeutic potential.

Based mainly on rodents studies, forty-hertz (40-Hz) physical stimulation has been regarded as a potential noninvasive treatment for Alzheimer's disease (AD). Considering the brain differences between rodents and humans, the effects of 40-Hz physical stimulation need to be further validated using nonhuman primates before its clinical application. Here, we took advantage of a rare opportunity to expose nine aged rhesus monkeys (26 to 31 y old) to 40-Hz auditory stimulation. Given the strong correlation between cerebrospinal fluid (CSF) Aβ and Tau concentrations and corresponding AD pathology in brain parenchyma in clinical practice, we investigated the effects of 40-Hz stimulation on AD pathology by monitoring changes in CSF Aβ and Tau concentrations. Our results revealed that 7 consecutive days of 40-Hz auditory stimulation triggered a rapid and significant increase of Aβ levels by more than 200%, but no effect on Tau levels in the CSF. Additionally, we observed that the elevation of CSF Aβ levels persisted for more than 5 wk after cessation, which had not been reported in any previous studies. After this, a pathological examination of the temporal cortices of 4 of the experimental monkeys was carried out and the data demonstrated that all of them had prevalent extracellular Aβ senile plaque pathology, whereas Tau pathology was negative or very weak. These results provide a good explanation for the differences between the CSF Aβ and Tau protein levels. Together, these first-time results from monkeys suggest that 40-Hz auditory stimulation has strong potential of a noninvasive AD treatment method.

DJ-1 is a genetic factor associated with Parkinson’s disease (PD), and altered DJ-1 function has been implicated in PD pathogenesis. However, DJ-1 knockout mice fail to reproduce robust PD-like phenotypes or neuropathology, leaving the contribution of DJ-1 deficiency to PD-related disease processes unresolved. To investigate this question in a species more closely related to primates than rodents, we used the tree shrew and performed bilateral, neuron-targeted DJ-1 knockout in the substantia nigra using an AAV-mediated in situ gene editing system. Four out of five DJ-1 knockout tree shrews developed key PD features, including motor abnormalities, substantial loss of nigral dopaminergic neurons, and aggregation of phosphorylated α-synuclein at serine 129 (PSer129αSyn). Notably, one DJ-1 knockout animal did not develop these phenotypes, despite comparable AAV transduction efficiency and DJ-1 knockout levels in the substantia nigra, suggesting that DJ-1 loss may not be solely sufficient in all cases and that additional modifying or compensatory factors may influence disease manifestation. Further pathological analysis showed that PSer129αSyn aggregation was associated with the development of PD-like phenotypes in this model. These findings support a model in which DJ-1 deficiency can promote key PD-like phenotypes in tree shrews, potentially involving PSer129αSyn accumulation, nigral dopaminergic neuron loss, and motor dysfunction. Given that multiple molecular pathways have been proposed to link DJ-1 dysfunction to PD, our results provide in vivo evidence supporting PSer129αSyn aggregation as an important pathological process associated with DJ-1 deficiency. This tree shrew model may therefore provide a useful experimental platform for studying DJ-1-related PD pathogenesis and evaluating potential therapeutic strategies.

Mapping of axon trajectories is crucial for understanding brain organization. Using whole-brain high-throughput fluorescence imaging, we developed a cytoarchitecture-based link estimation (CABLE) method for accurate fiber tract mapping at cellular resolution. This method infers the fiber direction from the inherent anisotropy of the nucleus or soma shape and spatial arrangement of adjacent cells. The inferred fiber tracts were validated by tracing virally labeled individual axons in the monkey brain. This CABLE method could disentangle complex intersecting or bending fibers that were uncertain in diffusion magnetic resonance imaging tractography, allowing accurate brain-wide fiber tract reconstruction in marmoset and macaque brains. Finally, we applied CABLE for rapid mapping of axon fiber abnormalities in diseased neonatal human brain tissues, establishing a path for high-resolution brain mapping of fiber tracts in the human brain. CABLE harnesses cytoarchitectural information such as cell or nuclear shape to infer fiber tracts in the brain of, for example, marmosets, macaques or humans.

The seasonal variations that occur in the gut microbiota of healthy adult rhesus monkeys kept in outdoor groups under conventional rearing patterns and how these variations are affected by environmental variables are relatively poorly understood. In this study, we collected 120 fecal samples from 30 adult male rhesus monkeys kept in outdoor groups across four seasons and recorded the temperature and humidity of the housing facilities, as well as the proportions of fruit and vegetables in their diet. A 16S rRNA sequencing analysis showed that the alpha diversity of the gut microbiota of the rhesus monkeys was higher in winter and spring than in summer and autumn. A principal coordinate analysis (PCoA) further demonstrated notable seasonal variations in the composition and functionality of the gut microbiota in the rhesus monkeys. The phyla Firmicutes and Bacteroidetes and the genus Prevotella 9 were the significantly dominant groups in all 120 fecal samples from the rhesus monkeys. A linear discriminant analysis (LDA) effect size (LEfSe) analysis (LDA > 4) indicated that at the phylum level, Firmicutes was significantly enriched in winter, Bacteroidetes was significantly enriched in summer, and Proteobacteria and Campylobacter were significantly enriched in spring. At the genus level, Helicobacter and Ralstonia were significantly enriched in spring; Prevotella 9, Streptococcus, and Prevotella were significantly enriched in summer; and UCG_005 was significantly enriched in autumn. The beneficial genera Lactobacillus, Limosilactobacillus, and Ligilactobacillus and the beneficial species Lactobacillus johnsonii, Limosilactobacillus reuteri, Ligilactobacillus murinus, and Lactobacillus amylovorus all showed the same seasonal trend; namely, their average relative abundance was markedly greater during the winter months compared to other seasons. Compared with other seasons, carbohydrate metabolic function was significantly upregulated in winter (p < 0.01), amino acid metabolic function was relatively increased in spring, and energy metabolic function and the metabolic function of cofactors and vitamins were significantly downregulated in winter and relatively upregulated in summer. A variance partitioning analysis (VPA) and redundancy analysis (RDA) showed that the proportions of fruits and vegetables in the diet, but not climatic factors (temperature and humidity), significantly influenced the seasonal changes in the gut microbiota. These variations were related to changes in the proportions of fruits and vegetables. This research presents novel findings regarding the influence of external environmental factors on the gastrointestinal environment of rhesus monkeys.

The surge in demand for experimental monkeys has led to a rapid increase in their costs. Consequently, there is a growing need for a cost-effective model of Parkinson disease (PD) that exhibits all core clinical and pathologic phenotypes. Evolutionarily, tree shrews (Tupaia belangeri) are closer to primates in comparison with rodents and could be an ideal species for modeling PD. To develop a tree shrew PD model, we used the 1-methyl-4-phenylpyridinium (MPP+), a metabolite derived from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, to induce lesions in dopaminergic neurons of the unilateral substantia nigra. The induced tree shrew model consistently exhibited and maintained all classic clinical manifestations of PD for a 5-month period. The symptoms included bradykinesia, rest tremor, and postural instability, and ∼50% individuals showed apomorphine-induced rotations, a classic phenotype of unilateral PD models. All these are closely resembled the ones observed in PD monkeys. Meanwhile, this model was also sensitive to L-dopa treatment in a dose-dependent manner, which suggested that the motor deficits are dopamine dependent. Immunostaining showed a significant loss of dopaminergic neurons (∼95%) in the lesioned substantia nigra, which is a crucial PD pathological marker. Moreover, a control group of nigral saline injection did not show any motor deficits and pathological changes. Cytomorphologic analysis revealed that the size of nigral dopaminergic neurons in tree shrews is much bigger than that of rodents and is close to that of macaques. The morphologic similarity may be an important structural basis for the manifestation of the highly similar phenotypes between monkey and tree shrew PD models. Collectively, in this study, we have successfully developed a PD model in a small animal species that faithfully recapitulated the classic clinical symptoms and key pathological indicators of PD monkeys, providing a novel and low-cost avenue for evaluation of PD treatments and underlying mechanisms.

Complex brain diseases seriously endanger human health, and early diagnostic biomarkers and effective treatments are currently lacking. Due to ethical constraints on human research, establishing monkey models is crucial to address these issues. With the rapid development of technology, transgenic monkey models of a range of brain diseases, especially autism spectrum disorder (ASD), have been successfully established. However, to establish practical and effective brain disease models and subsequently apply them to disease mechanism and treatment studies, there is still a lack of a standard tool, i.e., a system for collecting and analyzing the daily behaviors of brain disease model monkeys. Therefore, with the goal of undertaking a comprehensive and quantitative study of behavioral phenotypes, we established a standard daily behavior collection and analysis system, including behavioral data collection protocols and a monkey daily behavior ethogram (MDBE) for rhesus and cynomolgus monkeys, which are the most commonly used non-human primates in model construction. Then, we used ASD as an application example after referring to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), which is widely used in clinical disease diagnosis to obtain ASD core clinical symptoms. We then established a sub-ethogram (ASD monkey core behavior ethogram (MCBE-ASD)) specifically for quantitative assessment of the core clinical symptoms of an ASD monkey model based on MDBE. Subsequently, we demonstrated the high reproducibility of the system.

Cerebrospinal fluid (CSF) samples are commonly collected via lumbar puncture (LP) in both clinical and research settings for measurement of biomarkers of Alzheimer's disease (AD). To determine the effects of LP on CSF AD biomarkers, we collected CSF samples at seven different time points after an LP in rhesus monkeys. We find that amyloid-beta (Aβ) and Tau levels increased significantly on day 1, peaked on day 3, and returned to baseline on day 10 after LP. The NFL levels increased significantly on day 5, peaked on day 10, and returned to baseline after day 30. The increased AD biomarker levels were mainly due to CSF outflow and deep intrathecal invasion during LP. Therefore, if LPs are repeated within a short period of time, prior LP can affect Aβ and Tau levels within 10 days and NFL levels within 30 days, which may lead to clinical misdiagnosis or incorrect scientific conclusions.

As a prime mover in Alzheimer’s disease (AD), microglial activation requires membrane translocation, integration, and activation of the metamorphic protein chloride intracellular channel 1 (CLIC1), which is primarily cytoplasmic under physiological conditions. However, the formation and activation mechanisms of functional CLIC1 are unknown. Here, we found that the human antimicrobial peptide (AMP) LL-37 promoted CLIC1 membrane translocation and integration. It also activates CLIC1 to cause microglial hyperactivation, neuroinflammation, and excitotoxicity. In mouse and monkey models, LL-37 caused significant pathological phenotypes linked to AD, including elevated amyloid-β, increased neurofibrillary tangles, enhanced neuronal death and brain atrophy, enlargement of lateral ventricles, and impairment of synaptic plasticity and cognition, while Clic1 knockout and blockade of LL-37-CLIC1 interactions inhibited these phenotypes. Given AD’s association with infection and that overloading AMP may exacerbate AD, this study suggests that LL-37, which is up-regulated upon infection, may be a driving force behind AD by acting as an endogenous agonist of CLIC1.

The surge in demand for experimental monkeys has led to a rapid increase in their associated costs. Consequently, there is a growing need for the development of a cost-effective model for Parkinson’s disease (PD) that exhibits all core clinical and pathological phenotypes of PD. Evolutionarily, tree shrews ( Tupaia belangeri ) are much closer to primates in comparison to rodents and share more similar PD-related brain structures and movement ability with monkeys. As such, tree shrews represent an ideal small animal species for modeling PD. To develop a tree shrew PD model, we used the 1-Methyl-4-phenylpyridinium (MPP + ) metabolite, derived from the well-established PD modeling drug 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), to induce lesions in the dopaminergic neurons of the unilateral substantia nigra. After determining the optimal modeling dosage, the tree shrews consistently exhibited and maintained all classic clinical manifestations of PD for a 5-month period. The symptoms closely resembled the ones observed in PD monkeys and included bradykinesia, rest tremor, postural instability, and apomorphine-induced rotations, a classic phenotype of unilateral PD models. Immunostaining showed a significant loss of dopaminergic neurons (approximately 95%) in the substantia nigra on the lesioned side of the brain, a crucial pathological marker of PD. Further cytomorphological analysis revealed that the size of nigral dopaminergic neurons in tree shrews exceeded that of rodents and more closely approximated that of macaques. Based on the principle that structure determines function, the morphological similarity between tree shrews and monkeys may be an important structural basis for the manifestation of the highly similar phenotypes between monkey and tree shrew PD models. Collectively, this study successfully developed a PD model in a small animal species that faithfully recapitulated the classical clinical symptoms and key pathological indicators of PD monkeys. In addition to the well-recognized monkey models, the tree shrew model provides a novel avenue for the evaluation of PD treatments and underlying mechanisms.

OBJECTIVE:Anxious behaviors often occur in individuals who have experienced early adversity. Anxious behaviors can bring many hazards, such as social withdrawal, eating disorders, negative self-efficacy, self-injurious thoughts and behaviors, anxiety disorders, and even depression. Abnormal behavior are is closely related to changes in corresponding circuit functions in the brain. This study investigated the relationship between brain circuits and anxious behaviors in maternal-deprived rhesus monkey animal model, which mimic early adversity in human.METHODS:Twenty-five rhesus monkeys (Macaca mulatta) were grouped by two different rearing conditions: 11 normal control and mother-reared (MR) monkeys and 14 maternally deprived and peer-reared (MD) monkeys. After obtaining images of the brain areas with significant differences in maternal separation and normal control macaque function, the relationship between functional junction intensity and stereotypical behaviors was determined by correlation analysis.RESULTS:The correlation analysis revealed that stereotypical behaviors were negatively correlated with the coupling between the left lateral amygdala subregion and the left inferior frontal gyrus in both MD and MR macaques.CONCLUSION:This study suggests that early adversity-induced anxious behaviors are associated with changes in the strength of the amygdala-prefrontal connection. The normalization of the regions involved in the functional connection might reverse the behavioral abnormality. It provides a solid foundation for effective intervention in human early adversity.SIGNIFICANCE STATEMENT:This study suggests that early adversity-induced anxious behaviors are associated with changes in the strength of the amygdala-prefrontal connection. The higher the amygdala-prefrontal connection strength, the less stereotyped behaviors exhibited by monkeys experiencing early adversity. Thus, in the future, changing the strength of the amygdala-prefrontal connection may reverse the behavioral abnormalities of individuals who experience early adversity. This study provides a solid foundation for effective intervention in humans' early adversity.

The adult cortex has long been regarded as non-neurogenic. Whether injury can induce neurogenesis in the adult cortex is still controversial. Here, we report that focal ischemia stimulates a transient wave of local neurogenesis. Using 5′-bromo-2′-deoxyuridine labeling, we demonstrated a rapid generation of doublecortin-positive neuroblasts that died quickly in mouse cerebral cortex following ischemia. Nestin-CreER-based cell ablation and fate mapping showed a small contribution of neuroblasts by subventricular zone neural stem cells. Using a mini-photothrombotic ischemia mouse model and retrovirus expressing green fluorescent protein labeling, we observed maturation of locally generated new neurons. Furthermore, fate tracing analyses using PDGFRα-, GFAP-, and Sox2-CreER mice showed a transient wave of neuroblast generation in mild ischemic cortex and identified that Sox2-positive astrocytes were the major neurogenic cells in adult cortex. In addition, a similar upregulation of Sox2 and appearance of neuroblasts were observed in the focal ischemic cortex of Macaca mulatta. Our findings demonstrated a transient neurogenic response of Sox2-positive astrocytes in ischemic cortex, which suggests the possibility of inducing neuronal regeneration by amplifying this intrinsic response in the future.

Purpose To investigate the effects of different indoor lighting intensity (500 lx, 750 lx and 1,000 lx) on normal ocular axial length growth by using juvenal rhesus monkeys. Methods Twenty-four juvenile monkeys were exposed continuously to normal intensity light (NIL, 500 lx, n=16), medium intensity light (MIL, 750 lx, n=8) and high intensity light (HIL, 1 000 lx, n=8), with a same CCT value (about 3000 K) for 246 days. Axial length, anterior chamber depth, corneal curvature radius were measured at about a monthly interval. Results After 246 days of light exposure, the growth of axial length of the MIL group (750 lx) were 0.151 ± 0.081 mm and 0.139 ± 0.070 mm in the right and left eyes, respectively, and significantly larger in comparison with the NIL group (500lx, OD: 0.068 ± 0.055 mm, OS: 0.074 ± 0.057 mm) and the HIL group (1000lx,OD:0.063 ± 0.093 mm, OS: 0.084 ± 0.052 mm) monkeys. This effect was stable and robust during the whole experimental period. Conclusion The effects of different intensity lighting on normal ocular axial development was not linear as most people currently think. We must be cautious when it comes to elevate light intensity in classrooms. Whether this conclusion is correct under lights of other CCT value needs further study.

Intracerebroventricular (ICV) administration through cannulas is a direct way to deliver large molecules and substances that are blocked by the blood-brain barrier into the central nervous system (CNS). It is widely used in brain studies on monkeys. However, this method is invasive, as it requires guide cannulas to be implanted into the brain. Whether the long-term implantation of the cannula and the administration of molecule-delivering vehicles, usually saline, can affect the brain by inducing chronic CNS inflammation or even worse brain atrophy, remains an issue to be solved. To answer this question, we investigated inflammatory markers and brain structures on three vehicle-control monkeys who received cannula implantation and one-year ICV saline administration in another study. During the experiment, the monkeys’ cerebrospinal fluid (CSF) samples were collected periodically, and the level of three classic inflammatory markers (IL-1β, IL-6, and TNF-α) were measured by electrochemiluminescence immunoassay. The monkeys’ brain structures were imaged in vivo periodically by 9.4 Tesla magnetic resonance imaging, which can provide the best-resolution magnetic resonance images of living monkeys, and the volume of the hippocampus was measured to evaluate the brain atrophy. The data reveal that, during the administrating period, the long-term levels of the inflammatory markers in the CSF and the volumes of the hippocampus did not change significantly compared with the baseline. These results suggest that the long-term ICV administration of saline through cannulas did not induce chronic neuroinflammation or brain atrophy in these rhesus monkeys, suggesting chronic ICV administration via implanted cannulas is a reliable method in monkey brain research.

Alzheimer’s disease (AD) is the most common neurodegenerative disease. To date, its cause is unclear and there are no effective treatments or preventive measures. Despite there are accumulating evidences for the existence of AD pathological hallmarks in the brain of aging rhesus monkeys, it remains a mainstream notion that monkeys do not develop AD naturally. This is an important issue because it will determine how we use monkeys in AD studies. To settle down this issue, a group (n=10) of aged rhesus monkeys 26 years old or above went through a systematic AD screening procedure in this study. Three of these monkeys showed severe memory impairments (SMI) after evaluated with a classic working memory test. Further behavioral testing revealed that the SMI monkeys also exhibited apathy-like behavior, which is another core AD clinical symptom. In addition to the cognitive deficits, two of the three SMI monkeys developed all of the three AD pathological hallmarks, including neurofibrillary tangles, senile plaques and neuronal loss. According to the diagnostic criteria of human AD, the two SMI monkeys were clearly naturally occurring AD monkeys. These results suggest that AD is not a uniquely human disease and monkeys have great potential for the development of much needed etiological AD models, which are vital for better understanding of developmental process of AD and the base of identification of early diagnostic biomarkers and effective therapeutic targets of AD.