Nat Commun︱non-human primate (monkey marmoset) autism model reveals the biological abnormalities in the early development of human diseases

Author ︱ Fu Huimin, editor in charge ︱ Wang Sizhen title correction: "Monkey marmoset" is more "Marmoset" Autism spectrum disorder (ASD) is a multifactorial neurodegeneration with characteristic synapses and changes in gene expression For sexual diseases, patients have the characteristics of impaired social interaction and communication, repetitive behaviors, and limited interest
.

Reports indicate that more than 1% of the population has been diagnosed with ASD, but there is currently no effective cure [1]
.

The symptoms of ASD usually become obvious and diagnosable around 3 years old, so treatment at or earlier than this time point is advisable [2]
.

Early behavioral signs can predict the existing abnormalities in circuit development.
Understanding the biological abnormalities and pathogenesis of ASD in the early developmental stage is of positive significance for the development of effective drug treatments
.

 ASD is also called a synaptic disorder, which includes synaptic dysfunction at the structural and molecular levels
.

In patients with ASD, the dendritic spines of cortical neurons are affected [3]
.

In addition, multiple ASD-related genes are involved in synaptic function [4]
.

Under normal circumstances, synapse breeding is carried out in a precisely regulated manner: in the early stages of life, excessive synapse formation is followed by pruning [5]
.

Synaptic development involves two processes: gene programming of synapses and activity-dependent remodeling.
The damage of these processes may adversely affect normal circuits and subsequently produce ASD symptoms
.

 During the early developmental process after birth, the brain undergoes dramatic changes in neural circuit organization and gene expression
.

Synapses occur at their highest in the newborn period, and follow the experience-dependent circuit restructuring in childhood [6]
.

In fact, the sensitive period of language acquisition and social learning occurs in childhood [7]
.

Gene expression in the neonatal period also changes rapidly with the development of synapses [8]
.

Time-related regulation of synaptic structure or function and gene expression will link ASD-related synaptic phenotypes with molecular functions
.

 In September 2021, Professor Satoshi Watanabe (first author, corresponding author) and Professor Noritaka Ichinohe (corresponding author) from the National Institute of Neuroscience and National Center for Neurology and Psychiatry of Japan jointly published the question online on Nature Communications.
A research paper on "Functional and molecular characterization of a non-human primate model of autism spectrum disorder shows similarity with the human disease"
.

It was found that the marmoset model induced by valproic acid showed similar synapses, behaviors and molecular phenotypes to human ASD
.

In the early postpartum period of this model, synapse occurrence was reduced, while VPA marmosets had an increase in synapse occurrence during their infancy
.

In infancy, the synaptic plasticity of marmosets induced by valproic acid increased temporarily and was related to changes in vocalization, and differentially expressed genes were related to circuit remodeling
.

This study proves the importance of early phenotype in the pathogenesis of ASD and provides a new molecular target for early intervention of the disease
.

 Previous studies have shown that ASD primate models have advantages over rodent models to study the pathogenesis of ASD [9]
.

Among them, the offspring of marmosets induced by valproic acid (VPA) showed abnormalities in social behavior, axon bundle structure, and neuroimmune cells, which are consistent with human data [10-12]
.

Moreover, the previous research of the research group also found that the neuron structure and synaptic growth of marmosets are similar to those of humans [5]
.

 In this study, the authors first clarified the synaptic phenotype of the VPA-induced ASD marmoset model during synapseogenesis and pruning
.

By analyzing the excitatory synaptic structure and miniature excitatory postsynaptic currents (mEPSCs) of the third layer of pyramidal neurons in the Brodmann 8b/9 area of ​​VPA induced (VPA) and uninduced (UE) marmosets ) And mini-inhibitory postsynaptic currents (mIPSCs), they found that VPA-induced changes in spine density, mEPSC frequency, and mIPSCs frequency transition from underdevelopment at birth (0 months, newborn) to 6 months (puberty) ) Overdevelopment (Figure 1a-g)
.

In addition, the time-mediated processes of spinal density, mEPSCs and mIPSCs frequency are similar (Figure 1h)
.

VPA induction significantly lowered the ratio of mESPC frequency to mISPC frequency at 3 months (infancy), but did not change at 0 or 6 months (Figure 1 h, i)
.

Figure 1 In the VPA-induced marmoset, the early underdevelopment and late overdevelopment of excitatory synapses (picture quoted from: Watanabe S, et al.
, Nat Comm 2021; 12: 5388) Excitation-inhibition in the cortical circuit ( E/I) balance is regulated by synaptic plasticity, and abnormal E/I balance is a major hallmark feature of ASD [13]
.

In order to explore whether the above-mentioned changes in the E/I balance of VPA animals at 3 months were caused by the abnormal regulation of excitatory synapses, the researchers first induced long-term inhibition (LTD) by low-frequency stimulation.
The experiment found that VPA is age-dependent.
Sex (0-3 months) affects LTD induced by low-frequency stimulation (Figure 2 a, b)
.

And at 3 months, VPA induced changes in spinal volume and synaptic structure (Figure 2 c, d)
.

And at 3 months, the post-synaptic density (PSD) length of the dorsal medial prefrontal cortex of the marmoset in the VPA group, the field EPSP amplitude, and the log fold change (log fold change) value of the average spine volume were all significantly reduced (Figure 2 e, f )
.

The above results indicate that prenatal VPA exposure will affect the E/I ratio, LTD and spinal volume at 3 months, while the effect is weaker at other ages, indicating that 3 months is another time with a strong synaptic phenotype Point
.

Figure 2 Age-changing VPA induces long-term inhibition and spinal volume in marmosets (picture quoted from: Watanabe S, et al.
, Nat Comm 2021; 12: 5388) Next, the research team hypothesized that early synaptic breeding may be Affect early social behavior
.

By recording and annotating the calls of about 3 months old marmosets in an isolated environment, they found that the total number of calls of marmosets in the VPA group during isolation was lower, but there was no significant difference
.

Compared with UE marmosets, VPA marmosets produced a higher proportion of "phee" (homonymous fèi) voice calls (79%), which resulted in significantly lower call type entropy for animals in the VPA group than in the UE group (Figure 3)
.

In short, the behavioral abnormalities found in infancy may be the result of sudden fertility abnormalities from birth to infancy
.

Figure 3 VPA-induced changes in isolation calls in marmosets (picture quoted from: Watanabe S, et al.
, Nat Comm 2021;12: 5388) Considering that there are two synaptic phenotypes in the process of time regulation, One is most affected at 0 months (Figure 1h), and the other is most affected at 3 months (Figures 1k, 2f), so the research team speculates that these phenotypes are accompanied by changes in gene expression
.

Find VPA-regulated differentially expressed genes (DEGs) through microarray, and use k-means clustering method to divide DEGs into three clusters to analyze the time profile of gene expression (Figure 4)
.

It was found that cluster 1 contained genes related to abnormal synaptic development, cluster 2 and cluster 3 contained genes related to synaptic regulation that occurred specifically at 3 months (Figure 4a-f)
.

And cluster 1 is significantly enriched in ASD-related (SFARI) genes, cluster 2 is enriched in critical period related genes, and the expression is highest in the critical period
.

Pathway analysis showed that the synaptic signaling pathway was one of the highly affected pathways in clusters 1 and 3, and the cholesterol biosynthesis-related pathway was one of the highly affected pathways in clusters 1 and 2 (Figure 4g)
.

These findings indicate that genes affected by VPA at different times may be involved in different aspects of ASD synaptic regulation
.

Figure 4 Microarray analysis of differential gene expression (picture quoted from: Watanabe S, et al.
, Nat Comm 2021;12: 5388) Then using upstream analysis, researchers searched for potential drugs to make 0 months and 3 months The normalization of the changed biological function at the time
.

At month 0, they predicted a statin and an anti-inflammatory drug; at month 3, they predicted a variety of drugs that affect myelin, inflammation, and calcium signal transduction (Table 1)
.

Table 1 The upstream drugs predicted to normalize gene expression regulation at 0 M and 3 M (Table quoted from: Watanabe S, et al.
, Nat Comm 2021; 12: 5388) Finally, the research team compared VPA marmosets with humans Gene expression of ASD
.

The results showed that the gene expression of VPA marmosets at 3 and 6 months was significantly positively correlated with human ASD, and the gene expression at 0 months was not correlated with human ASD (Figure 5a)
.

The gene expression of the marmoset at 3 months was negatively correlated with the gene expression of neurons derived from ASD human induced pluripotent stem cells (iPSC), and the correlation between the gene expression of the marmoset at 0 months and the neurons derived from IPSC was more significant.
Low (Figure 5b)
.

The correlation between VPA marmosets (3 or 6 months) and human ASD samples after death was higher than the correlation between the rat VPA model at 35 days after birth and human samples (Figure 5c)
.

These data indicate that VPA marmosets have broad similarities with human ASD
.

Figure 5 The relationship between VPA-induced marmosets and human ASD gene expression regulation (Figure quoted from: Watanabe S, et al.
, Nat Comm 2021; 12: 5388) Figure 6 Summary of the article (Figure quoted from Watanabe S, et al .
, Nat Comm 2021;12: 5388) Article conclusion and discussion, inspiration and prospects.
This study found that the valproic acid (VPA) model marmoset and human ASD have more consistent gene modules, which shows that it is better than the rodent model.
More suitable as a human ASD model
.

In addition, this study emphasizes the importance of infant age in the pathogenesis of ASD, indicating that early organisms are essential for genotype in ASD.
The phenotype after the circuit is fully mature may be different from the phenotype observed before puberty.
And adult patients with ASD may require different treatments (Figure 6)
.

 However, this study has the following limitations
.

First of all, although the synaptic and molecular phenotypes of the infantile ASD marmoset model revealed in this study are similar to the overall situation of patients with idiopathic ASD, the effectiveness of the model will be determined if the subtype most representative of the model can be determined.
Further enhancement
.

Secondly, more and more evidences show that glial cells (astrocytes and microglia) are involved in the pathogenesis of ASD, but this study did not discuss the role of astrocytes
.

Third, the early intervention proposed in this study requires early screening and diagnosis, but it has not yet been fully determined
.

Nevertheless, this study may help future research on the age-dependent treatment of ASD
.

1038/s41467-021-25487-6 Selected articles from previous issues [1] Dev Cell︱ Lactic acid promotes peripheral nerve injury and repair B side: Long-term axon lactate metabolism increases will lead to oxidative stress and axon degeneration [2] Nat Commun︱ selective inhibition of microglia activation is expected to alleviate the transmission of pathological α-syn [3] Science︱ serotonin helps overcome cocaine addiction? [4] Mol Psychiatry︱ Gao Tianming’s research group reveals the different roles of astrocytes and neurons in synaptic plasticity and memory [5] Sci Transl Med︱ Xiang Xianyuan and others reveal the brain’s immune cells crazy sugar phagocytosis, helping nerves Early diagnosis of degenerative diseases [6] A new mechanism of Mol Cell︱ Alzheimer's disease: Tau protein oligomerization induces the RNA binding protein HNRNPA2B1 nuclear cell transport and mediates the enhancement of m6A-RNA modification [7] Cereb Cortex | Li Tao project The group reported the abnormality of the cortical myelin covariation network with deep characteristics of the cerebral cortex in schizophrenia [8] Cell︱ hold hands, advance and retreat together! The formation of a cellular network between microglia and the degradation of pathological α-syn [9] lipids and Alzheimer's disease! The lack of sulfatide in the myelin sheath of the central nervous system in adulthood can lead to Alzheimer’s disease-like neuroinflammation and cognitive impairment [10] EMBO J︱ neuron Miro1 protein loss destroys mitochondrial autophagy and overactivates the integrated stress response [10] 11] Science frontier review and interpretation ︱Regulatory mechanism of nicotinic acetylcholine receptor accessory molecules and application prospects of disease treatment and transformation [12] Neurosci Bull︱ synapse-associated protein Dlg1 improves depression-like behavior in mice by inhibiting microglia activation [13 】Brain | For the first time! PAX6 may be a key factor in the pathogenesis of Alzheimer’s disease and a new therapeutic target [14] Nat Biomed Eng︱Ye Yuru’s team developed a new strategy for whole-brain gene editing-mediated treatment of Alzheimer’s disease [15] Luo Liqun Science Center Interpretation of the system ︱Nerve loop structure-a high-quality scientific research training course recommendation for the system that makes the brain "computer" run at high speed [1] A guide to data graphs! How good is it to learn these software? 【2】JAMA Neurol︱Attention! Young people are more likely to suffer from "Alzheimer's disease"? [3] Patch clamp and optogenetics and calcium imaging technology seminar (October 30-31) References (slide up and down to view) [1] Casanova, M.