Marmoset Brain Research Articles

Astrocyte regional specialization is shaped by postnatal development.

Astrocytes are an abundant class of glial cells with critical roles in neural circuit assembly and function. Though many studies have uncovered significant molecular distinctions between astrocytes from different brain regions, how this regionalization unfolds over development is not fully understood. We used single-nucleus RNA sequencing to characterize the molecular diversity of brain cells across six developmental stages and four brain regions in the mouse and marmoset brain. Our analysis of over 170,000 single astrocyte nuclei revealed striking regional heterogeneity among astrocytes, particularly between telencephalic and diencephalic regions, at all developmental time points surveyed in both species. At the stages sampled, most of the region patterning was private to astrocytes and not shared with neurons or other glial types. Though astrocytes were already regionally patterned in late embryonic stages, this region-specific astrocyte gene expression signature changed dramatically over postnatal development, and its composition suggests that regional astrocytes further specialize postnatally to support their local neuronal circuits. Comparing across species, we found divergence in the expression of astrocytic region- and age-differentially expressed genes and the timing of astrocyte maturation relative to birth between mouse and marmoset, as well as hundreds of species differentially expressed genes. Finally, we used expansion microscopy to show that astrocyte morphology is largely conserved across gray matter forebrain regions in the mouse, despite substantial molecular divergence.

Investigating microstructural changes between in vivo and perfused ex vivo marmoset brains using oscillating gradient and b-tensor encoded diffusion MRI at 9.4 T.

To investigate microstructural alterations induced by perfusion fixation in brain tissues using advanced diffusion MRI techniques and estimate their potential impact on the application of ex vivo models to in vivo microstructure. We used oscillating gradient spin echo (OGSE) and b-tensor encoding diffusion MRI to examine in vivo and ex vivo microstructural differences in the marmoset brain. OGSE was used to shorten effective diffusion times, whereas b-tensor encoding allowed for the differentiation of isotropic and anisotropic kurtosis. Additionally, we performed Monte Carlo simulations to estimate the potential microstructural changes in the tissues. We report large changes (˜50%-60%) in kurtosis frequency dispersion (OGSE) and in both anisotropic and isotropic kurtosis (b-tensor encoding) after perfusion fixation. Structural MRI showed an average volume reduction of about 10%. Monte Carlo simulations indicated that these alterations could likely be attributed to extracellular fluid loss possibly combined with axon beading and increased dot compartment signal fraction. Little evidence was observed for reductions in axonal caliber. Our findings shed light on advanced MRI parameter changes that are induced by perfusion fixation and potential microstructural sources for these changes. This work also suggests that caution should be exercised when applying ex vivo models to infer in vivo tissue microstructure, as significant differences may arise.

Similarity and characterization of structural and functional neural connections within species under isoflurane anesthesia in the common marmoset

The common marmoset is an essential model for understanding social cognition and neurodegenerative diseases. This study explored the structural and functional brain connectivity in a marmoset under isoflurane anesthesia, aiming to statistically overcome the effects of high inter-individual variability and noise-related confounds such as physiological noise, ensuring robust and reliable data. Similarities and differences in individual subject data, including assessments of functional and structural brain connectivities derived from resting-state functional MRI and diffusion tensor imaging were meticulously captured. The findings highlighted the high consistency of structural neural connections within the species, indicating a stable neural architecture, while functional connectivity under anesthesia displayed considerable variability. Through independent component and dual regression analyses, several distinct brain connectivities were identified, elucidating their characteristics under anesthesia. Insights into the structural and functional features of the marmoset brain from this study affirm its value as a neuroscience research model, promising advancements in the field through fundamental and translational studies.

An anesthetic protocol for preserving functional network structure in the marmoset monkey brain

Abstract Initiatives towards acquiring large-scale neuroimaging data in non-human primates promise improving translational neuroscience and cross-species comparisons. Crucial among these efforts is the need to expand sample sizes while reducing the impact of anesthesia on the functional properties of brain networks. Yet, the effects of anesthesia on non-human primate brain networks remain unclear. Here, we demonstrate using functional magnetic resonance imaging (fMRI) at 9.4 tesla that isoflurane anesthesia induces a variety of brain states in the marmoset brain with dramatically altered functional connectivity profiles. As an alternative, we recommend using a continuous infusion of the sedative medetomidine, supplemented with a low concentration of isoflurane. Using this protocol in eight marmosets, we observed robust visual activation during flickering light stimulation and identified resting-state networks similar to the awake state. In contrast, isoflurane alone led to a suppressed visual activation and the absence of awake-like network patterns. Comparing states using a graph-theoretical approach, we confirmed that the structure of functional networks is preserved under our proposed anesthesia protocol but is lost using isoflurane alone at concentration levels greater than 1%. We believe that the widespread adoption of this protocol will be a step towards advancing translational neuroscience initiatives in non-human primate neuroimaging. To promote the collaborative use of neuroimaging resources, we openly share our datasets (https://zenodo.org/records/11118775).

Long-range projections of oxytocin neurons in the marmoset brain.

The neurohormone oxytocin (OT) has become a major target for the development of novel therapeutic strategies to treat psychiatric disorders such as autism spectrum disorder because of its integral role in governing many facets of mammalian social behavior. Whereas extensive work in rodents has produced much of our knowledge of OT, we lack basic information about its neurobiology in primates making it difficult to interpret the limited effects that OT manipulations have had in human patients. In fact, previous studies have revealed only limited OT fibers in primate brains. Here, we investigated the OT connectome in marmoset using immunohistochemistry, and mapped OT fibers throughout the brains of adult male and female marmoset monkeys. We found extensive OT projections reaching limbic and cortical areas that are involved in the regulation of social behaviors, such as the amygdala, the medial prefrontal cortex, and the basal ganglia. The pattern of OT fibers observed in marmosets is notably similar to the OT connectomes described in rodents. Our findings here contrast with previous results by demonstrating a broad distribution of OT throughout the marmoset brain. Given the prevalence of this neurohormone in the primate brain, methods developed in rodents to manipulate endogenous OT are likely to be applicable in marmosets.

New AAV9 engineered variants with enhanced neurotropism and reduced liver off-targeting in mice and marmosets

Although adeno-associated virus 9 (AAV9) has been highly exploited as delivery platform for gene-based therapies, its efficacy is hampered by low efficiency in crossing the adult blood-brain barrier (BBB) and pronounced targeting to the liver upon intravenous delivery. We generated a new galactose binding-deficient AAV9 peptide display library and selected two new AAV9 engineered capsids with enhanced targeting in mouse and marmoset brains after intravenous delivery. Interestingly, the loss of galactose binding greatly reduced undesired targeting to peripheral organs, particularly the liver, while not compromising transduction of the brain vasculature. However, the galactose binding was necessary to efficiently infect non-endothelial brain cells. Thus, the combinatorial actions of the galactose-binding domain and the incorporated displayed peptide are crucial to enhance BBB crossing along with brain cell transduction. This study describes two novel capsids with high brain endothelial infectivity and extremely low liver targeting based on manipulating the AAV9 galactose-binding domain.

Structural MRI analysis of age-related changes and sex differences in marmoset brain volume

The field of aging biology, which aims to extend healthy lifespans and prevent age-related diseases, has turned its focus to the Callithrix jacchus (common marmoset) to understand the aging process better. This study utilized magnetic resonance imaging (MRI) to non-invasively analyze the brains of 216 marmosets, investigating age-related changes in brain structure; the relationship between body weight and brain volume; and potential differences between males and females. The key findings revealed that, similar to humans, Callithrix jacchus experiences a reduction in total intracranial volume, cortex, subcortex, thalamus, and cingulate volumes as they age, highlighting site-dependent changes in brain tissue. Notably, the study also uncovered sex differences in cerebellar volume. These insights into the structural connectivity and volumetric changes in the marmoset brain throughout aging contribute to accumulating valuable knowledge in the field, promising to inform future aging research and interventions for enhancing healthspan.

Commonality and variance of resting-state networks in common marmoset brains

Animal models of brain function are critical for the study of human diseases and development of effective interventions. Resting-state network (RSN) analysis is a powerful tool for evaluating brain function and performing comparisons across animal species. Several studies have reported RSNs in the common marmoset (Callithrixjacchus; marmoset), a non-human primate. However, it is necessary to identify RSNs and evaluate commonality and inter-individual variance through analyses using a larger amount of data. In this study, we present marmoset RSNs detected using > 100,000 time-course image volumes of resting-state functional magnetic resonance imaging data with careful preprocessing. In addition, we extracted brain regions involved in the composition of these RSNs to understand the differences between humans and marmosets. We detected 16 RSNs in major marmosets, three of which were novel networks that have not been previously reported in marmosets. Since these RSNs possess the potential for use in the functional evaluation of neurodegenerative diseases, the data in this study will significantly contribute to the understanding of the functional effects of neurodegenerative diseases.

The Subcortical Atlas of the Marmoset ("SAM") monkey based on high-resolution MRI and histology.

A comprehensive three-dimensional digital brain atlas of cortical and subcortical regions based on MRI and histology has a broad array of applications in anatomical, functional, and clinical studies. We first generated a Subcortical Atlas of the Marmoset, called the "SAM," from 251 delineated subcortical regions (e.g. thalamic subregions, etc.) derived from high-resolution Mean Apparent Propagator-MRI, T2W, and magnetization transfer ratio images ex vivo. We then confirmed the location and borders of these segmented regions in the MRI data using matched histological sections with multiple stains obtained from the same specimen. Finally, we estimated and confirmed the atlas-based areal boundaries of subcortical regions by registering this ex vivo atlas template to in vivo T1- or T2W MRI datasets of different age groups (single vs. multisubject population-based marmoset control adults) using a novel pipeline developed within Analysis of Functional NeuroImages software. Tracing and validating these important deep brain structures in 3D will improve neurosurgical planning, anatomical tract tracer injections, navigation of deep brain stimulation probes, functional MRI and brain connectivity studies, and our understanding of brain structure-function relationships. This new ex vivo template and atlas are available as volumes in standard NIFTI and GIFTI file formats and are intended for use as a reference standard for marmoset brain research.

Remodeling of the postsynaptic proteome in male mice and marmosets during synapse development

Postsynaptic proteins play crucial roles in synaptic function and plasticity. During brain development, alterations in synaptic number, shape, and stability occur, known as synapse maturation. However, the postsynaptic protein composition changes during development are not fully understood. Here, we show the trajectory of the postsynaptic proteome in developing male mice and common marmosets. Proteomic analysis of mice at 2, 3, 6, and 12 weeks of age shows that proteins involved in synaptogenesis are differentially expressed during this period. Analysis of published transcriptome datasets shows that the changes in postsynaptic protein composition in the mouse brain after 2 weeks of age correlate with gene expression changes. Proteomic analysis of marmosets at 0, 2, 3, 6, and 24 months of age show that the changes in the marmoset brain can be categorized into two parts: the first 2 months and after that. The changes observed in the first 2 months are similar to those in the mouse brain between 2 and 12 weeks of age. The changes observed in marmoset after 2 months old include differential expression of synaptogenesis-related molecules, which hardly overlap with that in mice. Our results provide a comprehensive proteomic resource that underlies developmental synapse maturation in rodents and primates.

Decomposing cortical activity through neuronal tracing connectome-eigenmodes in marmosets

Deciphering the complex relationship between neuroanatomical connections and functional activity in primate brains remains a daunting task, especially regarding the influence of monosynaptic connectivity on cortical activity. Here, we investigate the anatomical-functional relationship and decompose the neuronal-tracing connectome of marmoset brains into a series of eigenmodes using graph signal processing. These cellular connectome eigenmodes effectively constrain the cortical activity derived from resting-state functional MRI, and uncover a patterned cellular-functional decoupling. This pattern reveals a spatial gradient from coupled dorsal-posterior to decoupled ventral-anterior cortices, and recapitulates micro-structural profiles and macro-scale hierarchical cortical organization. Notably, these marmoset-derived eigenmodes may facilitate the inference of spontaneous cortical activity and functional connectivity of homologous areas in humans, highlighting the potential generalizing of the connectomic constraints across species. Collectively, our findings illuminate how neuronal-tracing connectome eigenmodes constrain cortical activity and improve our understanding of the brain’s anatomical-functional relationship.

Mapping of facial and vocal processing in common marmosets with ultra-high field fMRI

Primate communication relies on multimodal cues, such as vision and audition, to facilitate the exchange of intentions, enable social interactions, avoid predators, and foster group cohesion during daily activities. Understanding the integration of facial and vocal signals is pivotal to comprehend social interaction. In this study, we acquire whole-brain ultra-high field (9.4 T) fMRI data from awake marmosets (Callithrix jacchus) to explore brain responses to unimodal and combined facial and vocal stimuli. Our findings reveal that the multisensory condition not only intensifies activations in the occipito-temporal face patches and auditory voice patches but also engages a more extensive network that includes additional parietal, prefrontal and cingulate areas, compared to the summed responses of the unimodal conditions. By uncovering the neural network underlying multisensory audiovisual integration in marmosets, this study highlights the efficiency and adaptability of the marmoset brain in processing facial and vocal social signals, providing significant insights into primate social communication.

A reappraisal of the default mode and frontoparietal networks in the common marmoset brain.

In recent years the common marmoset homolog of the human default mode network (DMN) has been a hot topic of discussion in the marmoset research field. Previously, the posterior cingulate cortex regions (PGM, A19M) and posterior parietal cortex regions (LIP, MIP) were defined as the DMN, but some studies claim that these form the frontoparietal network (FPN). We restarted from a neuroanatomical point of view and identified two DMN candidates: Comp-A (which has been called both the DMN and FPN) and Comp-B. We performed GLM analysis on auditory task-fMRI and found Comp-B to be more appropriate as the DMN, and Comp-A as the FPN. Additionally, through fingerprint analysis, a DMN and FPN in the tasking human was closer to the resting common marmoset. The human DMN appears to have an advanced function that may be underdeveloped in the common marmoset brain.

Early parental deprivation during primate infancy has a lifelong impact on gene expression in the male marmoset brain

Adverse early life experiences are well-established risk factors for neurological disorders later in life. However, the molecular mechanisms underlying the impact of adverse experiences on neurophysiological systems throughout life remain incompletely understood. Previous studies suggest that social attachment to parents in early development are indispensable for infants to grow into healthy adults. In situations where multiple offspring are born in a single birth in common marmosets, human hand-rearing is employed to ensure the survival of the offspring in captivity. However, hand-reared marmosets often exhibit behavioral abnormalities, including abnormal vocalizations, excessive attachment to the caretaker, and aggressive behavior. In this study, comprehensive transcriptome analyses were conducted on hippocampus tissues, a neuroanatomical region sensitive to social attachment, obtained from human hand-reared (N = 6) and parent-reared male marmosets (N = 5) at distinct developmental stages. Our analyses revealed consistent alterations in a subset of genes, including those related to neurodevelopmental diseases, across different developmental stages, indicating their continuous susceptibility to the effects of early parental deprivation. These findings highlight the dynamic nature of gene expression in response to early life experiences and suggest that the impact of early parental deprivation on gene expression may vary across different stages of development.

Comparative analyses of the Smith-Magenis syndrome protein RAI1 in mice and common marmoset monkeys.

Retinoic acid-induced 1 (RAI1) encodes a transcriptional regulator critical for brain development and function. RAI1 haploinsufficiency in humans causes a syndromic autism spectrum disorder known as Smith-Magenis syndrome (SMS). The neuroanatomical distribution of RAI1 has not been quantitatively analyzed during the development of the prefrontal cortex, a brain region critical for cognitive function and social behaviors and commonly implicated in autism spectrum disorders, including SMS. Here, we performed comparative analyses to uncover the evolutionarily convergent and divergent expression profiles of RAI1 in major cell types during prefrontal cortex maturation in common marmoset monkeys (Callithrix jacchus) and mice (Mus musculus). We found that while RAI1 in both species is enriched in neurons, the percentage of excitatory neurons that express RAI1 is higher in newborn mice than in newborn marmosets. By contrast, RAI1 shows similar neural distribution in adult marmosets and adult mice. In marmosets, RAI1 is expressed in several primate-specific cell types, including intralaminar astrocytes and MEIS2-expressing prefrontal GABAergic neurons. At the molecular level, we discovered that RAI1 forms a protein complex with transcription factor 20 (TCF20), PHD finger protein 14 (PHF14), and high mobility group 20A (HMG20A) in the marmoset brain. In vitro assays in human cells revealed that TCF20 regulates RAI1 protein abundance. This work demonstrates that RAI1 expression and protein interactions are largely conserved but with some unique expression in primate-specific cells. The results also suggest that altered RAI1 abundance could contribute to disease features in disorders caused by TCF20 dosage imbalance.

Physiological and pathological 3R and 4R tau expression in marmoset brain

AbstractBackgroundCommon marmosets (Callithrix jacchus) have recently emerged as an important model for studying aging and neurodegenerative disorders, including Alzheimer’s disease (AD). Amyloid‐β deposits in the cerebral cortex of marmosets present naturally with aging, which has now been widely reported. However, the role of tau in the marmoset brain has been understudied. The purpose of the present studies was to comprehensively examine 3R and 4R tau isoform expression in the marmoset brain.MethodsThe mRNA expression in the marmoset brain was confirmed by RT‐PCR. The total mRNA was isolated from frozen tissue of various age groups and reverse transcribed to cDNA, which was used for RT‐PCR. The sequence of each fragment was confirmed by the Sanger sequencing method. The tau protein expression in Sarkosyl soluble and insoluble fractions was examined by western blot using tau‐specific antibodies, and expression levels of 3R/4R were quantified by Dot blot. Synaptic tau expression was analyzed from crude synaptosome extractions of the frontal cortex. Pathological tau aggregates in cryo‐slices of a 10‐year‐old marmoset brain were visualized by immunohistochemistry.Results3R and 4R tau were expressed in the marmoset brain, with 3R tau predominately expressed in neonatal brains and 4R tau in adult/aged brains. 3R and 4R tau were also localized in synaptic regions of the frontal cortex. The Sarkosyl soluble tau was phosphorylated on T181, T217, and T231 sites with evidence of oligomers. Insoluble tau was phosphorylated on S396/S404 and S202/S205 sites and contained high molecular weight aggregates comprising 3R and 4R tau. Moreover, a 10‐year‐old marmoset brain case study demonstrated a paired helical filament structure in the hippocampus and intracellular 3R and 4R tau accumulation.ConclusionsOur results reveal physiological and pathological 3R/4R tau distributions in the frontal and temporal cortex of the marmoset brain, confirming the presence of 3R tau and AD‐like pathological tau in aging marmosets. These data support the utility of common marmosets as appropriate models for studying AD and neurodegenerative disorders.

Assessing amyloid plaque burden in aging marmosets and genetically engineered PSEN1 mutation carriers using 11C‐PiB PET

AbstractBackgroundThere is an urgent need to develop novel animal models to investigate the underlying cellular and molecular root causes of the pathogenesis and progression of AD. Our group has worked to establish the common marmoset as the first primate‐specific model of AD to reveal the earliest cellular and molecular events of AD processes and allow charting of AD progression from its inception. For this, we established a colony of outbred marmosets and used genetic engineering techniques to generate marmosets carrying the PSEN1‐C410Y and PSEN1‐A426P mutations that cause early‐onset, familial AD. The present study aims to use PET imaging to access and track the progression of Ab plaque burden non‐invasively and longitudinally in our marmoset models of AD.MethodMarmosets anesthetized with isoflurane delivered via a facemask were placed in a preclinical PET/CT scanner customized with marmoset‐specific beds. Respiratory rate, heart rate, arterial O2 saturation, and rectal temperature were monitored and maintained at normal physiological values. Our PET imaging protocol follows the Alzheimer’s Disease Neuroimaging Initiative (ADNI). The amyloid‐binding 11C‐Pittsburgh Compound B (11C‐PiB) was delivered intravenously in doses varying from 18.5 – 185 MBq (0.5 – 5 mCi). A 90‐min dynamic acquisition was performed immediately following the radiotracer injection, followed by a 3D CT scan acquired at 200 µm isotropic resolution. After the PET/CT neuroimaging scan, the marmosets were recovered from anesthesia and returned to their home cages.ResultWe observed positive 11C‐PiB binding and retention in the brains of aging outbred marmosets and in marmosets harboring PSEN1 mutations. Significant 11C‐PiB retention was observed in the cortex and white matter tracts. The areas with the highest 11C‐PiB retention were the lateral frontal cortex, anterior cingulate cortex, and temporal lobe regions.ConclusionThis study demonstrates using 11C‐PiB to track Ab plaque burden in the brains of aging marmosets and marmosets harboring PSEN1 mutations. As observed in human patients of AD, the amount of 11C‐PiB bound (measured in SUV and SUVR units) varied from animal to animal, and we are currently performing group analysis to investigate the dependence of 11C‐PiB retention on age and sex. This research was funded by NIH/NIA grants R24AG073190 and U19AG074866.

Assessing amyloid plaque burden in aging marmosets and genetically engineered PSEN1 mutation carriers using 11C‐PiB PET

AbstractBackgroundThere is an urgent need to develop novel animal models to investigate the underlying cellular and molecular root causes of the pathogenesis and progression of AD. Our group has worked to establish the common marmoset as the first primate‐specific model of AD to reveal the earliest cellular and molecular events of AD processes and allow charting of AD progression from its inception. For this, we established a colony of outbred marmosets and used genetic engineering techniques to generate marmosets carrying the PSEN1‐C410Y and PSEN1‐A426P mutations that cause early‐onset, familial AD. The present study aims to use PET imaging to access and track the progression of Ab plaque burden non‐invasively and longitudinally in our marmoset models of AD.MethodMarmosets anesthetized with isoflurane delivered via a facemask were placed in a preclinical PET/CT scanner customized with marmoset‐specific beds. Respiratory rate, heart rate, arterial O2 saturation, and rectal temperature were monitored and maintained at normal physiological values. Our PET imaging protocol follows the Alzheimer’s Disease Neuroimaging Initiative (ADNI). The amyloid‐binding 11C‐Pittsburgh Compound B (11C‐PiB) was delivered intravenously in doses varying from 18.5 – 185 MBq (0.5 – 5 mCi). A 90‐min dynamic acquisition was performed immediately following the radiotracer injection, followed by a 3D CT scan acquired at 200 µm isotropic resolution. After the PET/CT neuroimaging scan, the marmosets were recovered from anesthesia and returned to their home cages.ResultWe observed positive 11C‐PiB binding and retention in the brains of aging outbred marmosets and in marmosets harboring PSEN1 mutations. Significant 11C‐PiB retention was observed in the cortex and white matter tracts. The areas with the highest 11C‐PiB retention were the lateral frontal cortex, anterior cingulate cortex, and temporal lobe regions.ConclusionThis study demonstrates using 11C‐PiB to track Ab plaque burden in the brains of aging marmosets and marmosets harboring PSEN1 mutations. As observed in human patients of AD, the amount of 11C‐PiB bound (measured in SUV and SUVR units) varied from animal to animal, and we are currently performing group analysis to investigate the dependence of 11C‐PiB retention on age and sex.This research was funded by NIH/NIA grants R24AG073190 and U19AG074866.

Serum biomarkers associated with aging and neurodegeneration in common marmosets (Callithrix jacchus)

The common marmoset (Callithrix jacchus), a small South American monkey, is an important nonhuman primate model in the study of aging and age-related neurodegenerative disease, including Alzheimer’s disease, Parkinson’s disease, and related dementias. Thorough characterization of the wild type marmoset brain agingmodel, including biomarkers of aging and neural degeneration, will further the marmoset’s utility in translational research. We measured serum concentration of four key biomarkers of neural degeneration [total tau (T-tau), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and ubiquitin C-terminal hydrolase-L1 (UCH-L1)] via single molecule array from 24 marmosets (female n = 13, male n = 11) ranging in age from 1.3 to 18.7 years. Aged marmosets (>7 years) had significantly higher GFAP, NfL, UCH-L1, and T-tau than adult marmosets. Sex differences were not detected for any of these biomarker concentrations. These data provide an important initial range of reference values for GFAP, NfL, T-tau, and UCH-L1 to evaluate aging and neural health in marmosets, as well as evaluation of therapeutics in clinical models of disease.

GDF11 slows excitatory neuronal senescence and brain ageing by repressing p21

As a major neuron type in the brain, the excitatory neuron (EN) regulates the lifespan in C. elegans. How the EN acquires senescence, however, is unknown. Here, we show that growth differentiation factor 11 (GDF11) is predominantly expressed in the EN in the adult mouse, marmoset and human brain. In mice, selective knock-out of GDF11 in the post-mitotic EN shapes the brain ageing-related transcriptional profile, induces EN senescence and hyperexcitability, prunes their dendrites, impedes their synaptic input, impairs object recognition memory and shortens the lifespan, establishing a functional link between GDF11, brain ageing and cognition. In vitro GDF11 deletion causes cellular senescence in Neuro-2a cells. Mechanistically, GDF11 deletion induces neuronal senescence via Smad2-induced transcription of the pro-senescence factor p21. This work indicates that endogenous GDF11 acts as a brake on EN senescence and brain ageing.