A common NTRK2 variant is associated with emotional arousal and brain white-matter integrity in healthy young subjects

A head start: The relationship of placental factors to craniofacial and brain development

In recent years, the importance of placental function for fetal neurodevelopment has become increasingly studied. This field, known as neuroplacentology, has greatly expanded possible etiologies of neurodevelopmental disorders by exploring the influence of placental function on brain development. It is also well-established that brain development is influenced by craniofacial morphogenesis. However, there is less focus on the impact of the placenta on craniofacial development. Recent research suggests the functional influence of placental nutrients and hormones on craniofacial skeletal growth, such as prolactin, growth hormone, insulin-like growth factor 1, vitamin D, sulfate, and calcium, impacting both craniofacial and brain development. Therefore, interactions between the placenta and both fetal neurodevelopment and craniofacial development likely influence the growth and morphology of the head as a whole. This review discusses the role of placental hormone production and nutrient delivery in the development of the fetal head-defined as craniofacial and brain tissue together-expanding on the more established focus on brain development to also include the skull (or cranium) and face.

Sex-specific Regulation of Fentanyl Reward by the Circadian Transcription Factor NPAS2

Synthetic opioids like fentanyl are highly potent and prevalent in the illicit drug market, leading to tolerance, dependence, and opioid use disorder (OUD). Chronic opioid use disrupts sleep and circadian rhythms, which persist even during treatment and abstinence, increasing the risk of relapse. The body's molecular clock, regulated by transcriptional and translational feedback loops, controls various physiological processes, including the expression of endogenous opioids and their receptors. The circadian transcription factor NPAS2, highly expressed in the nucleus accumbens, may have a crucial function in opioid-related behaviors. Our study found sex-specific roles for NPAS2-mediated reward behaviors in male and female mice, including in fentanyl seeking and craving. We also identified specific cell types and transcriptional targets in the nucleus accumbens of both mice and humans by which NPAS2 may mediate the impact of fentanyl on brain physiology and in opioid reward-related behaviors. Ultimately, our findings begin to uncover the mechanisms underlying circadian rhythm dysfunction and opioid addiction.

Human lineage mutations regulate RNA-protein binding of conserved genes NTRK2 and ITPR1 involved in human evolution

Background

The role of human lineage mutations (HLMs) in human evolution through post-transcriptional modification is unclear.

Aims

To investigate the contribution of HLMs to human evolution through post-transcriptional modification.

Methods

We applied a deep learning model Seqweaver to predict how HLMs impact RNA-binding protein affinity.

Results

We found that only 0.27% of HLMs had significant impacts on RNA-binding proteins at the threshold of the top 1% of human common variations. These HLMs enriched in a set of conserved genes highly expressed in adult excitatory neurons and prenatal Purkinje neurons, and were involved in synapse organisation and the GTPase pathway. These genes also carried excess damaging coding mutations that caused neurodevelopmental disorders, ataxia and schizophrenia. Among these genes, NTRK2 and ITPR1 had the most aggregated evidence of functional importance, suggesting their essential roles in cognition and bipedalism.

Conclusions

Our findings suggest that a small subset of human-specific mutations have contributed to human speciation through impacts on post-transcriptional modification of critical brain-related genes.

Childhood urbanicity is associated with emotional episodic memory-related striatal function and common variation in NTRK2

BACKGROUND

Childhoods in urban or rural environments may differentially affect the risk of neuropsychiatric disorders, possibly through memory processing and neural response to emotional stimuli. Genetic factors may not only influence individuals' choices of residence but also modulate how the living environment affects responses to episodic memory.

METHODS

We investigated the effects of childhood urbanicity on episodic memory in 410 adults (discovery sample) and 72 adults (replication sample) with comparable socioeconomic statuses in Beijing, China, distinguishing between those with rural backgrounds (resided in rural areas before age 12 and relocated to urban areas at or after age 12) and urban backgrounds (resided in cities before age 12). We examined the effect of childhood urbanicity on brain function across encoding and retrieval sessions using an fMRI episodic memory paradigm involving the processing of neutral or aversive pictures. Moreover, genetic association analyses were conducted to understand the potential genetic underpinnings that might contribute to memory processing and neural mechanisms influenced by early-life urban or rural environments.

RESULTS

Episodic memory retrieval accuracy for more difficult neutral stimuli was similar between those with urban and rural childhoods, whereas aversive stimuli elicited higher retrieval accuracy in the urban group (P = 0.023). For aversive stimuli, subjects with urban childhood had relatively decreased engagement of the striatum at encoding and decreased engagement of the hippocampus at retrieval. This more efficient striatal encoding of aversive stimuli in those with urban childhoods was associated with common variation in neurotrophic tyrosine kinase receptor type 2 (NTRK2) (right striatum: P = 1.58×10-6). These findings were confirmed in the replication sample.

CONCLUSIONS

We suggest that this differential striatal processing of aversive stimuli observed in individuals with urban or rural childhoods may represent mechanisms by which childhood urbanicity may affect brain circuits, heightening behavioral responses to negative stressors associated with urban environments. NTRK2-associated neural processes in the striatum may play a role in these processes.

Single-cell RNA-seq data analysis reveals functionally relevant biomarkers of early brain development and their regulatory footprints in human embryonic stem cells (hESCs)

The complicated process of neuronal development is initiated early in life, with the genetic mechanisms governing this process yet to be fully elucidated. Single-cell RNA sequencing (scRNA-seq) is a potent instrument for pinpointing biomarkers that exhibit differential expression across various cell types and developmental stages. By employing scRNA-seq on human embryonic stem cells, we aim to identify differentially expressed genes (DEGs) crucial for early-stage neuronal development. Our focus extends beyond simply identifying DEGs. We strive to investigate the functional roles of these genes through enrichment analysis and construct gene regulatory networks to understand their interactions. Ultimately, this comprehensive approach aspires to illuminate the molecular mechanisms and transcriptional dynamics governing early human brain development. By uncovering potential links between these DEGs and intelligence, mental disorders, and neurodevelopmental disorders, we hope to shed light on human neurological health and disease. In this study, we have used scRNA-seq to identify DEGs involved in early-stage neuronal development in hESCs. The scRNA-seq data, collected on days 26 (D26) and 54 (D54), of the in vitro differentiation of hESCs to neurons were analyzed. Our analysis identified 539 DEGs between D26 and D54. Functional enrichment of those DEG biomarkers indicated that the up-regulated DEGs participated in neurogenesis, while the down-regulated DEGs were linked to synapse regulation. The Reactome pathway analysis revealed that down-regulated DEGs were involved in the interactions between proteins located in synapse pathways. We also discovered interactions between DEGs and miRNA, transcriptional factors (TFs) and DEGs, and between TF and miRNA. Our study identified 20 significant transcription factors, shedding light on early brain development genetics. The identified DEGs and gene regulatory networks are valuable resources for future research into human brain development and neurodevelopmental disorders.

Primate-specific stress-induced transcription factor POU2F1Z protects human neuronal cells from stress

The emergence of new primate-specific genes is an essential factor in human and primate brain development and functioning. POU2F1/Oct-1 is a transcription regulator in higher eukaryotes which is involved in the regulation of development, differentiation, stress response, and other processes. We have demonstrated that the Tigger2 transposon insertion into the POU2F1 gene which occurred in the primate lineage led to the formation of an additional exon (designated the Z-exon). Z-exon-containing primate-specific Oct-1Z transcript includes a short upstream ORF (uORF) located at its 5’-end and the main ORF encoding the Oct-1Z protein isoform (Pou2F1 isoform 3, P14859-3), which differs from other Oct-1 isoforms by its N-terminal peptide. The Oct-1Z-encoding transcript is expressed mainly in human brain cortex. Under normal conditions, the translation of the ORF coding for the Oct-1Z isoform is repressed by uORF. Under various stress conditions, uORF enables a strong increase in the translation of the Oct-1Z-encoding ORF. Increased Oct-1Z expression levels in differentiating human neuroblasts activate genes controlling stress response, neural cell differentiation, brain formation, and organogenesis. We have shown that the Oct-1Z isoform of the POU2F1/Oct-1 transcription factor is an example of a primate-specific genomic element contributing to brain development and cellular stress defense.

Primary hypothyroidism and autoimmune thyroiditis alter the transcriptional activity of genes regulating neurogenesis in the blood of patients

Objective. Thyroid hormones play an important role in the development and maturation of the central nervous symptom and their failure in the prenatal period leading to an irreversible brain damage. Their effect on the brain of adult, however, has not been fully studied. With the discovery of neurogenesis in the adult brain, many recent studies have been focused on the understanding the basic mechanisms controlling this process. Many neurogenesis regulatory genes are not only transcribed but also translated into the blood cells. The goal of our study was to analyze the transcriptional activity of neurogenesis regulatory genes in peripheral blood cells in patients with thyroid pathology.Methods. The pathway-specific PCR array (Neurotrophins and Receptors RT2 Profiler PCR Array, QIAGEN, Germany) was used to identify and validate the neurogenesis regulatory genes expression in patients with thyroid pathology and control group.Results. The results showed that GFRA3, NGFR, NRG1, NTF3, NTRK1, and NTRK2 significantly decreased their expression in patients with autoimmune thyroiditis with rising serum of autoantibodies. The patients with primary hypothyroidism, as a result of autoimmune thyroiditis and postoperative hypothyroidism, had significantly lower expression of FGF2, NGFR, NRG1, and NTF3. The mRNA level of CNTFR was markedly decreased in the group of patients with postoperative hypothyroidism. No change in the ARTN, PSPN, TFG, MT3, and NELL1 expression was observed in any group of patients.Conclusion. The finding indicates that a decrease in thyroid hormones and a high level of autoantibodies, such as anti-thyroglobulin antibody and anti-thyroid peroxidase antibody, affect the expression of mRNA neurogenesis-regulated genes in patients with thyroid pathology.

A major role for common genetic variation in anxiety disorders

Anxiety disorders are common, complex psychiatric disorders with twin heritabilities of 30-60%. We conducted a genome-wide association study of Lifetime Anxiety Disorder (ncase = 25 453, ncontrol = 58 113) and an additional analysis of Current Anxiety Symptoms (ncase = 19 012, ncontrol = 58 113). The liability scale common variant heritability estimate for Lifetime Anxiety Disorder was 26%, and for Current Anxiety Symptoms was 31%. Five novel genome-wide significant loci were identified including an intergenic region on chromosome 9 that has previously been associated with neuroticism, and a locus overlapping the BDNF receptor gene, NTRK2. Anxiety showed significant positive genetic correlations with depression and insomnia as well as coronary artery disease, mirroring findings from epidemiological studies. We conclude that common genetic variation accounts for a substantive proportion of the genetic architecture underlying anxiety.

An Analysis of Five TrkB Gene Polymorphisms in Schizophrenia and the Interaction of Its Haplotype with rs6265 BDNF Gene Polymorphism

Aim

The BDNF dysfunction in the schizophrenia has been soundly documented. The TrkB gene is a high-affinity receptor of the BDNF that is changed in schizophrenia and mood disorders. The study had two aims: first, to identify whether the five nucleotide polymorphisms (SNPs) in TrkB gene are associated with a diagnosis of schizophrenia; and the latter, if any association exists between the TrkB SNPs and psychopathology, suicide attempts, and family history of schizophrenia in a Caucasian population.

Methods

Case-control study (401 patients and 657 healthy controls) was used to examine a predisposition for schizophrenia. The tests for psychopathology, suicide attempts, and family history of schizophrenia were conducted only in patient group. The severity of the schizophrenia was measured using the five-factor model of the PANSS. In addition, the haplotype analysis for both the separate for SNPs of TrkB gene and in combination with the rs6265 SNP BDNF gene was conducted.

Results

Our case-control study revealed that the genetic variants of rs10868235 (T/T polymorphic genotype) and rs1387923 (G/G polymorphic genotype) of the TrkB gene were associated with a higher risk of developing schizophrenia in men. However, the A/A wild genotype of rs1387923 was connected with a lower risk for both the development of and the family manifestation of schizophrenia in men. The G polymorphic allele of rs1565445 was associated with an increased risk of suicide in schizophrenia. The tested SNPs of the TrkB gene did not modulate the psychopathology of schizophrenia. The haplotype that was built with five SNPs in the TrkB gene was protective for men, but after joining the rs6265 SNP of the BDNF gene, a haplotype that was protective for women was created.

Obsessive-compulsive disorder and growth factors: A comparative review

The goal of this article is to clarify the role of various growth factors in the establishment and progression of obsessive-compulsive disorder (OCD). OCD is a chronic mental disorder with recurrent intrusive thoughts and/or repetitive compulsive behaviors that increase during stressful periods. Growth and neurotrophic factors may be contributing factors in the pathophysiology of OCD. Many of them are synthesized and released within the central nervous system and act as trophic agents in neurons; some of them are involved in brain growth, development, neurogenesis, myelination and plasticity, while others take part in the protection of the nervous system following brain injuries. This paper attempts to identify all articles investigating the relationship between OCD and neurotrophic and growth factors, in both animal and human studies, with a focus on adult brain studies. Based on the PubMed and Scopus and Science Direct search tools, the available articles and studies are reviewed. Out of 230 records in total, the ones related to our review topic were taken into account to further understand the pathophysiological mechanism(s) of OCD, providing methods to improve its symptoms via the modification of neurotrophins and growth factor imbalances.

A tropomyosin receptor kinase family protein, NTRK2 is a potential predictive biomarker for lung adenocarcinoma

Neurotrophic receptor tyrosine kinase 2 (NTRK2) is a member of the tropomyosin receptor kinase family associated with the tumor development. However, the detailed function of NTRK2 in lung cancer, especially in lung adenocarcinoma (LUAD), is still not fully understood. Here, we investigated the effects of NTRK2 on LUAD biology. Through analyzing bioinformatics data derived from several databases, such as Oncomine, Gene Expression Profiling Interactive Analysis and UALCAN, we found that NTRK2 expression was significantly decreased in LUAD tissues. Clinical data acquired from Wanderer database, which is linked to The Cancer Genome Atlas database, demonstrated that the expression and methylation site of NTRK2 were significantly related to the clinical characteristics and prognosis of LUAD. Furthermore, NTRK2 expression was increased remarkably after treatment with the protein kinase B (AKT) inhibitor MK2206 and the anticancer agent actinomycin D. Functional enrichment analysis of NTRK2-associated coexpression genes was further conducted. Together, our results suggested that downregulated NTRK2 might be used in the diagnostic and prognostic evaluation of LUAD patients, or as a potential therapeutic target for the treatment of LUAD.

Haplotypes of coping behavior associated QTL regions reveal distinct transcript profiles in amygdala and hippocampus

Stress response and coping behavior in pigs are largely shaped by hypothalamic-pituitary-adrenal axis and sympatho-adrenomedullary system action. However, the dynamic interaction between amygdala and hippocampus crucially modulates the behavioral response towards significant emotional events. While this functional relationship is well documented, the molecular underpinnings still remain insufficiently understood. Our study used transcriptome profiling of porcine amygdala and hippocampus to identify molecular pathways that are differentially activated depending on the haplotype of a significantly coping behavior-associated region on pig chromosome 12 (SSC12). The pigs were classified into two groups based on the haplotype information of this QTL-region discovered in our previous genome-wide association study. Ten each of high- (HR) and low- (LR) reactive pigs (n = 20) were selected for differential gene expression analysis and weighted gene co-expression analysis with subsequent pathway analysis. Differentially expressed genes identified in the amygdala include SELL, CXCR7 and NTS, while TRAF3, PTGS2 and CFI were detected in the hippocampus indicating a role of neuroinflammation and immunological processes. Pathway analysis revealed IL-8 signaling, NF-κB signaling, glutamate and GABA metabolism, glucocorticoid receptor signaling and chemokine signaling in the amygdala and ephrin receptor signaling, as well as NF-κB signaling in the hippocampus. We discovered candidate genes in regions detected by genome-wide association study including ARRB2, ADRBK2, THRB, NEK7 and ACVR2B, which relate to dopaminergic and other monoaminergic neurotransmitter systems, neuroimmunomodulation, neuroinflammation and GABA-ergic neurotransmission. These findings provide insights into the molecular underpinning of divergent coping behavior and associated haplotypes in limbic forebrain system in pig.

Investigating the genetic profile of dopaminergic neurons in the VTA in response to perinatal nicotine exposure using mRNA-miRNA analyses

Maternal smoking during pregnancy is associated with an increased risk of developmental, behavioral, and cognitive deficits. Nicotine, the primary addictive component in tobacco, has been shown to modulate changes in gene expression when exposure occurs during neurodevelopment. The ventral tegmental area (VTA) is believed to be central to the mechanism of addiction because of its involvement in the reward pathway. The purpose of this study was to build a genetic profile for dopamine (DA) neurons in the VTA and investigate the disruptions to the molecular pathways after perinatal nicotine exposure. Initially, we isolated the VTA from rat pups treated perinatally with either nicotine or saline (control) and collected DA neurons using fluorescent-activated cell sorting. Using microarray analysis, we profiled the differential expression of mRNAs and microRNAs from DA neurons in the VTA in order to explore potential points of regulation and enriched pathways following perinatal nicotine exposure. Furthermore, mechanisms of miRNA-mediated post-transcriptional regulation were investigated using predicted and validated miRNA-gene targets in order to demonstrate the role of miRNAs in the mesocorticolimbic DA pathway. This study provides insight into the genetic profile as well as biological pathways of DA neurons in the VTA of rats following perinatal nicotine exposure.

NTRK2 (TrkB gene) variants and temporal lobe epilepsy: A genetic association study

OBJECTIVE

The NTRK2 gene encodes a member of the neurotrophic tyrosine kinase receptor family known as TrkB. It is a membrane-associated receptor with signaling and cellular differentiation properties that has been involved in neuropsychiatric disorders, including epilepsy. We report here the frequencies of NTRK2 allele variants in patients with temporal lobe epilepsy (TLE) compared to controls without epilepsy and explore the impact of these polymorphisms on major clinical variables in TLE.

METHODS

A case-control study comparing the frequencies of the NTRK2 gene polymorphisms beween 198 TLE Caucasian patients and 200 matching controls without epilepsy. In a second step, the impact of allelic variation on major clinical and electroencephalographic epilepsy variables was evaluated in the group of TLE patients. The following polymorphisms were determined by testing different regions of the NTRK2 gene: rs1867283, rs10868235, rs1147198, rs11140800, rs1187286, rs2289656, rs1624327, rs1443445, rs3780645, and rs2378672. To correct for multiple correlations the level of significance was set at p<0.01.

RESULTS

Patients with TLE showed a statistical trend for increase of the T/T genotype in rs10868235 compared to control (O.R.=1.90; 95%CI=1.17-3.09; p=0.01). Homozygous patients for the A allele in rs1443445 had earlier mean age at onset of seizures, p=0.009 (mean age of 16.6 versus 22.4years). We also observed that the T allele in rs3780645 was more frequent in patients who needed polytheraphy for seizure control than in patients on monotherapy, (O.R.=4.13; 95%CI=1.68-10.29; p=0.001). This finding may reflect an increased difficulty to obtain seizure control in this group of patients. No additional differences were observed in this study.

CONCLUSIONS

Patients with epilepsy showed a trend for a difference in rs10868235 allelic distribution compared to controls without epilepsy. NTRK2 variability influenced age at seizure onset and the pharmacological response to seizure control. As far as we know, this is the first study showing an association between NTKR2 allelic variants in human epilepsy. We believe that further studies in this venue will shade some light on the molecular mechanisms involved in epileptogenesis and in the clinical characteristics of epilepsy.

Tyrosine receptor kinase B gene variants (NTRK2 variants) are associated with depressive disorders in temporal lobe epilepsy

RATIONALE

Psychiatric comorbidities are highly prevalent in epilepsy, adding an important burden to the disease and profoundly affecting the quality of life of these individuals. Patients with temporal lobe epilepsy (TLE) are especially at risk to develop depression and several lines of evidence suggest that the association of depression with epilepsy might be related to common biological substrates. In this study, we test whether NTRK2 allele variants are associated with mood disorders or depressive disorders in patients with TLE.

METHODS

An association study of 163 patients with TLE. The NTRK2 variants studied were rs1867283, rs10868235, rs1147198, rs11140800, rs1187286, rs2289656, rs1624327, rs1443445, rs3780645, and rs2378672. All patients were submitted to the Structured Clinical Interview for DSM-IV (SCID) and epilepsy patients with mood disorders or depressive disorders were compared to epilepsy patients without mood disorders or depressive disorders.

RESULTS

In our TLE cohort, 76 patients (46.6%) showed mood disorders. After logistic regression, independent risk factors for mood disorders in TLE were female sex, presence of concomitant anxiety disorders, and genetic variations in rs1867283 and rs10868235 NTRK2 variants. Depressive disorders accounted for this results and independent variables associated with depressive disorders in TLE were female sex (OR=2.59; 95%CI=1.15-5.82; p=0.021), presence of concomitant anxiety disorders (OR=3.72; 95%CI=1.71-8.06; p=0.001) or psychotic disorders (OR=3.86; 95%CI=1.12-13.25; p=0.032), A/A genotype in the rs1867283 NTRK2 gene (OR=3.06; 95%CI=1.25-7.50; p=0.015) and C/C genotype in the rs10868235 NTRK2 gene (OR=3.54; 1.55-8.08; p=0.003). Similarly, these genotypes also remained independently and significantly associated with depressive disorders when patients with depressive disorders were compared to TLE patients without any psychiatric comorbidity.

CONCLUSION

In the present study, female sex, presence of concomitant anxiety or psychotic disorders, and specific allelic variations in the NTRK2 gene were independently associated with mood disorders or depressive disorders in TLE. If our results were confirmed, variants in the NTRK2 gene could be considered as risk factors or biomarkers for depressive disorders in patients with TLE.