Temperament traits mediate the relationship between CACNA1C polymorphisms and bipolar disorder in cisgender women

The influence of temperament traits on bipolar disorder (BD) has been investigated. Both temperament traits and BD are partially genetically determined and seem to be influenced by variations in the CACNA1C gene. These variations presented a significant interactive effect with biological sex, although studies that evaluate this relationship are scarce. Here, we assessed the mediation effect of temperament traits on the relationship between two polymorphisms in the CACNA1C gene (rs1006737 and rs4765913) and BD according to sex. This is a cross-sectional study consisting of 878 Caucasian individuals (508 women and 370 men), aged 18-35, enrolled in a population-based study in the city of Pelotas, Southern Brazil. BD diagnosis was evaluated using the clinical interview MINI 5.0, and temperament traits were assessed via the application of the Affective and Emotional Composite Temperament Scale (AFECTS). Mediation models were tested using the modeling tool PROCESS (version 3.3) for SPSS. Bootstrapping-enhanced mediation analyses in women indicated that traits anger (39%) and caution (27%) mediated the association between the rs4765913 SNP and BD, while traits volition (29%), anger (35%), and caution (29%) mediated the association between the AA haplotype (rs1006737-rs4765913) and the BD. No effect was encountered for cisgender men. Our model revealed that paths from CACNA1C SNPs to BD are mediated by specific temperament traits in women, reinforcing the definition of temperament traits as endophenotypes.

BDNF Levels According to Variations in the CACNA1C Gene: Sex-Based Disparity

The CACNA1C gene encodes the pore-forming alpha-1c subunit of L-type voltage-gated calcium channels. The calcium influx through these channels regulates the transcription of the brain-derived neurotrophic factor (BDNF). Polymorphisms in this gene have been consistently associated with psychiatric disorders, and alterations in BDNF levels are a possible biological mechanism to explain such associations. Here, we sought to investigate the effect of the CACNA1C rs1006737 and rs4765913 polymorphisms and their haplotypes on serum BDNF concentration. We further aim to investigate the regulatory function of these SNPs and the ones linked to them. The study enrolled 641 young adults (362 women and 279 men) in a cross-sectional population-based survey. Linear regression was used to test the effects of polymorphisms and haplotypes on BDNF levels adjusted for potential confounders. Moreover, regulatory putative functional roles were assessed using in silico approach. BDNF levels were not associated with CACNA1C polymorphisms/haplotype in the total sample. When the sample was stratified by sex, checking the effect of polymorphisms on men and women separately, the A-allele of rs4765913 was associated with lower BDNF levels in women compared with the TT genotype (p = 0.010). The AA (rs1006737-rs4765913) haplotype was associated with BDNF levels in opposite directions regarding sex, with lower levels of BDNF in women (p = 0.040) compared to those without this haplotype, while with higher levels in men (p = 0.027). These findings were supported by the presence of regulatory marks only on the male fetal brain. Our results suggest that the BDNF levels regulation may be a potential mechanism underpinning the association between CACNA1C and psychiatric disorders, with a differential role in women and men.

Association between CACNA1C gene rs100737 polymorphism and glutamatergic neurometabolites in bipolar disorder

Abnormalities in Ca²⁺ homeostasis in Bipolar Disorders (BD) have been associated with impairments in glutamatergic receptors and voltage-gated calcium channels. Increased anterior cingulate cortex (ACC) glutamatergic neurometabolites have been consistently disclosed in BD by proton magnetic resonance spectroscopy (¹H-MRS). A single nucleotide polymorphism (SNP) in the CACNA1C gene (rs1006737), which encodes the alpha 1-C subunit of the L-type calcium channel, has been associated with BD and is reported to modulate intra-cellular Ca²⁺. Thus, this study aimed to explore the association of the CACNA1C genotype with ACC glutamatergic metabolites measured by ¹H-MRS in both BD and HC subjects. A total of 194 subjects (121 euthymic BD type I patients and 73 healthy controls (HC) were genotyped for CACNA1C rs1006737, underwent a 3-Tesla ¹H-MRS imaging examination and ACC glutamatergic metabolite were assessed. We found overall increased glutamatergic metabolites in AA carriers in BD. Specifically, higher Glx/Cr was observed in subjects with the AA genotype compared to both AG and GG in the overall sample (BD + HC). Also, female individuals in the BD group with AA genotype were found to have higher Glx/Cr compared to those with other genotypes. CACNA1C AA carriers in use of anticonvulsant medication had higher estimated Glutamine (Glx-Glu) than the other genotypes. Thus, this study suggest an association between calcium channel genetics and increased glutamatergic metabolites in BD, possibly playing a synergic role in intracellular Ca²⁺ overload and excitotoxicity.

CACNA1C Gene rs1006737 Polymorphism Affects Cognitive Performance in Chinese Han Schizophrenia

OBJECTIVE

To investigate the relationship between L-type calcium channel α1C subunit (CACNA1C) gene polymorphism and schizophrenia (SCZ) and cognitive function in the Han nationality, the main nationality in China.

METHODS

Genotyping of CACNA1C SNP (rs1006737, rs1024582, rs2007044) in SCZ patients (n = 312) and healthy controls (n = 305) was performed. Cognitive function was assessed in the SCZ patients using Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Then, the correlation between SNP and SCZ, as well as cognition, was calculated.

RESULTS

There was no significant difference in allele frequency and genotype distribution frequency of the three polymorphic loci of CACNA1C gene between the two groups. In cognitive tests, delayed memory scores in RBANS were significantly lower in rs1006737 "A" risk allele carriers than in non-carriers.

CONCLUSION

There is no significant difference in allele and genotype frequency of CANCA1C Gene rs1006737, rs1024582 and rs2007044 between the schizophrenia patients and healthy controls. The cognitive function of schizophrenia patients is correlated with the rs1006737, and the delayed memory of "A" allele carriers is significantly reduced.

Sex-Dependent Effects of the APOE ɛ4 Allele on Behavioral Traits and White Matter Structures in Young Adults

The APOE ɛ4 allele is associated with a risk of Alzheimer’s disease in the elderly, with the association being pronounced in females. Conversely, findings of the effects of the APOE ɛ4 allele in young adults are mixed. Here, we investigated the sex–genotype interaction effects of the APOE ɛ4 allele on cognitive functions as well as brain structures among 1258 young adults. After adjusting for multiple comparisons, there were significant effects of the interaction between sex and the number of APOE ɛ4 allele on some speed tasks (e.g., simple processing speed tasks and the reverse Stroop task) as well as on regional white matter volume (rWMV). The observed sex–genotype interaction conferred better cognitive performance and greater rWMV in the anterior frontal and precentral white matter areas in females having more APOE ɛ4 alleles and reduced rWMV in the same areas in male having more APOE ɛ4 alleles. These findings support the long-debated antagonistic pleiotropic effects of the APOE ɛ4 allele in females.

Sex and Estrous Cycle Effects on Anxiety- and Depression-Related Phenotypes in a Two-Hit Developmental Stress Model

Stress during sensitive developmental periods can adversely affect physical and psychological development and contribute to later-life mental disorders. In particular, adverse experiences during childhood dramatically increase the risk for the development of depression and anxiety disorders. Although women of reproductive age are twice as likely to develop anxiety and depression than men of the corresponding age, little is known about sex-specific factors that promote or protect against the development of psychopathology. To examine potential developmental mechanisms driving sex disparity in risk for anxiety and depression, we established a two-hit developmental stress model including maternal separation in early life followed by social isolation in adolescence. Our study shows complex interactions between early-life and adolescent stress, between stress and sex, and between stress and female estrogen status in shaping behavioral phenotypes of adult animals. In general, increased locomotor activity and body weight reduction were the only two phenotypes where two stressors showed synergistic activity. In terms of anxiety- and depression-related phenotypes, single exposure to early-life stress had the most significant impact and was female-specific. We show that early-life stress disrupts the protective role of estrogen in females, and promotes female vulnerability to anxiety- and depression-related phenotypes associated with the low-estrogenic state. We found plausible transcriptional and epigenetic alterations in psychiatric risk genes, Nr3c1 and Cacna1c, that likely contributed to the stress-induced behavioral effects. In addition, two general transcriptional regulators, Egr1 and Dnmt1, were found to be dysregulated in maternally-separated females and in animals exposed to both stressors, respectively, providing insights into possible transcriptional mechanisms that underlie behavioral phenotypes. Our findings provide a novel insight into developmental risk factors and biological mechanisms driving sex differences in depression and anxiety disorders, facilitating the search for more effective, sex-specific treatments for these disorders.

The Effects of Family Socioeconomic Status on Psychological and Neural Mechanisms as Well as Their Sex Differences

Family socioeconomic status (SES) is an important factor that affects an individual’s neural and cognitive development. The two novel aims of this study were to reveal (a) the effects of family SES on mean diffusivity (MD) using diffusion tensor imaging given the characteristic property of MD to reflect neural plasticity and development and (b) the sex differences in SES effects. In a study cohort of 1,216 normal young adults, we failed to find significant main effects of family SES on MD; however, previously observed main effects of family SES on regional gray matter volume and fractional anisotropy (FA) were partly replicated. We found a significant effect of the interaction between sex and family income on MD in the thalamus as well as significant effects of the interaction between sex and parents’ educational qualification (year’s of education) on MD and FA in the body of the corpus callosum as well as white matter areas between the anterior cingulate cortex and lateral prefrontal cortex. These results suggest the sex-specific associations of family SES with neural and/or cognitive mechanisms particularly in neural tissues in brain areas that play key roles in basic information processing and higher-order cognitive processes in a way females with greater family SES level show imaging outcome measures that have been associated with more neural tissues (such as greater FA and lower MD) and males showed opposite.