Associations of common genetic risk variants of the muscarinic acetylcholine receptor M2 with cardiac autonomic dysfunction in patients with schizophrenia

OBJECTIVES

Decreased vagal modulation, which has consistently been observed in schizophrenic patients, might contribute to increased cardiac mortality in schizophrenia. Previously, associations between CHRM2 (Cholinergic Receptor Muscarinic 2) and cardiac autonomic features have been reported. Here, we tested for possible associations between these polymorphisms and heart rate variability in patients with schizophrenia.

METHODS

A total of three single nucleotide polymorphisms (SNPs) in CHRM2 (rs73158705 A>G, rs8191992 T>A and rs2350782 T>C) that achieved significance (p < 5 * 10^-8) in genome-wide association studies for cardiac autonomic features were genotyped in 88 drug-naïve patients, 61 patients receiving antipsychotic medication and 144 healthy controls. Genotypes were analysed for associations with parameters of heart rate variability and complexity, in each diagnostic group.

RESULTS

We observed a significantly altered heart rate variability in unmedicated patients with identified genetic risk status in rs73158705 A>G, rs8191992 T>A and rs2350782 T>C as compared to genotype non-risk status. In patients receiving antipsychotic medication and healthy controls, these associations were not observed.

DISCUSSION

We report novel candidate genetic associations with cardiac autonomic dysfunction in schizophrenia, but larger cohorts are required for replication.

Association between genetic variants of the cholinergic system and postoperative delirium and cognitive dysfunction in elderly patients

Background

Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are frequent and serious complications after surgery. We aim to investigate the association between genetic variants in cholinergic candidate genes according to the Kyoto encyclopedia of genes and genomes - pathway: cholinergic neurotransmission with the development of POD or POCD in elderly patients.

Methods

This analysis is part of the European BioCog project (www.biocog.eu), a prospective multicenter observational study with elderly surgical patients. Patients with a Mini-Mental-State-Examination score ≤ 23 points were excluded. POD was assessed up to seven days after surgery using the Nursing Delirium Screening Scale, Confusion Assessment Method and a patient chart review. POCD was assessed three months after surgery with a neuropsychological test battery. Genotyping was performed on the Illumina Infinium Global Screening Array. Associations with POD and POCD were analyzed using logistic regression analysis, adjusted for age, comorbidities and duration of anesthesia (for POCD analysis additionally for education). Odds ratios (OR) refer to minor allele counts (0, 1, 2).

Results

745 patients could be included in the POD analysis, and 452 in the POCD analysis. The rate of POD within this group was 20.8% (155 patients), and the rate of POCD was 10.2% (46 patients). In a candidate gene approach three genetic variants of the cholinergic genes CHRM2 and CHRM4 were associated with POD (OR [95% confidence interval], rs8191992: 0.61[0.46; 0.80]; rs8191992: 1.60[1.22; 2.09]; rs2067482: 1.64[1.10; 2.44]). No associations were found for POCD.

Conclusions

We found an association between genetic variants of CHRM2 and CHRM4 and POD. Further studies are needed to investigate whether disturbances in acetylcholine release and synaptic plasticity are involved in the development of POD.

Trial registration: ClinicalTrials.gov: NCT02265263.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01071-1.

Dysregulation of Synaptic Signaling Genes Is Involved in Biology of Uterine Leiomyoma

Uterine leiomyomas are tumors, which are hormone driven and originate from the smooth muscle layer of the uterine wall. In addition to known genes in leiomyoma pathogenesis, recent approaches also highlight epigenetic malfunctions as an important mechanism of gene dysregulation. RNA sequencing raw data from pair-matched normal myometrium and fibroid tumors from two independent studies were used as discovery and validation sets and reanalyzed. RNA extracted from normal myometrium and fibroid tumors from 58 Slovenian patients was used as independent confirmation of most significant differentially expressed genes. Subsequently, GWA data from leiomyoma patients were used in order to identify genetic variants at epigenetic marks. Gene Ontology analysis of the overlap of two independent RNA-seq analyses showed that NPTX1, NPTX2, CHRM2, DRD2 and CACNA1A were listed as significant for several enriched GO terms. All five genes were subsequently confirmed in the independent Slovenian cohort. Additional integration and functional analysis showed that genetic variants in these five gene regions are listed at a chromatin structure and state, predicting promoters, enhancers, DNase hypersensitivity and altered transcription factor binding sites. We identified a unique subgroup of dysregulated synaptic signaling genes involved in the biology and pathogenesis of leiomyomas, adding to the complexity of tumor biology.

CHRM2 Genotype Affects Inhibitory Control Mechanisms During Cognitive Flexibility

The cholinergic system is one of the most important neurotransmitter systems, but knowledge about the relevance of the cholinergic muscarinergic receptor system for cognitive functions is still scarce. Evidence suggests that the cholinergic muscarinic 2 receptor (CHRM2) plays an important role in the processing of cueing/prior information that help to increase the efficacy of lower-level attentional processes. In the current study, we investigated whether this is also the case for higher-level cognitive flexibility mechanisms. To this end, we tested N = 210 healthy adults with a backward inhibition task, in which prior information needs to be used to guide cognitive flexibility mechanisms. Testing different polymorphisms of the CHRM2 gene, we found that variation in this gene play a role in cognitive flexibility. It could be demonstrated that rs8191992 TT genotype carriers are better able to suppress no longer relevant information and to use prior information for cognitive flexibility, compared to A allele carriers. We further found that rs2350780 GG genotype carriers performed worse than A allele carriers. The results broaden the relevance of the CHRM2 system for cognitive functions beyond attentional selection processes. Corroborating recent theories on the relevance of the cholinergic system for cognitive processes, these results suggest that CHRM2 is important to process of "prior information" needed to inform subsequent cognitive operations. Considering the importance of prior information for adaptive behavioral control, it is possible that CHRM2 also modulates other instances of higher-level cognitive processes as long as these require the processing of "prior information."

M3-subtype muscarinic receptor activation stimulates intracellular calcium oscillations and aldosterone production in human adrenocortical HAC15 cells

A previous body of work in bovine and rodent models shows that cholinergic agonists modulate the secretion of steroid hormones from the adrenal cortex. In this study we used live-cell Ca²⁺ imaging to investigate cholinergic activity in the HAC15 human adrenocortical carcinoma cell line. The cholinergic agonists carbachol and acetylcholine triggered heterogeneous Ca²⁺ oscillations that were strongly inhibited by antagonists with high affinity for the M₃ muscarinic receptor subtype, while preferential block of M₁ or M₂ receptors was less effective. Acute exposure to carbachol and acetylcholine modestly elevated aldosterone secretion in HAC15 cells, and this effect was also diminished by M₃ inhibition. HAC15 cells expressed relatively high levels of mRNA for M₃ and M₂ receptors, while M₁ and M₅ mRNA were much lower. In conclusion, our data extend previous findings in non-human systems to implicate the M₃ receptor as the dominant muscarinic receptor in the human adrenal cortex.

Neural and genetic correlates of binge drinking among college women

Ninety-seven female students were assigned to groups consisting of 55 infrequent and 42 frequent binge drinkers. The groups were compared on self-report measures of impulsivity, sensation seeking, and alexithymia, as well as several measures relevant to neural and genetic mechanisms, such as brain activation during a time estimation task and selected genotypes. Analyses of stimulus-locked brain activity revealed a slow cortical potential over the right parietal cortex during time estimation that was more negative among frequent binge drinkers. This group also showed a greater prevalence of a CHRM2 genotype previously associated with substance dependence and Major Depressive Disorder as well as a modest elevation on a non-planning impulsiveness scale. We conclude that the enhanced brain activation shown by binge drinkers compensates for an underlying deficit. That deficit may be reflected in poor planning skills and a genetic difference indicating increased risk for problems in later life.

Cholinergic receptor gene (CHRM2) variation and familial loading for alcohol dependence predict childhood developmental trajectories of P300

P300 amplitude in childhood predicts substance use disorders by young adulthood. Trajectories of visual P300 amplitude show an association between low amplitude P300 and familial risk for alcohol dependence (AD). Variation in the cholinergic muscarinic receptor gene (CHRM2) has previously been associated with P300 amplitude and AD. The present study used group based trajectory modeling of auditory P300 data collected longitudinally from offspring in families with and without familial loading for AD to determine if specific trajectories would be associated with familial risk and CHRM2 variation. Trajectory modeling confirms previous reports of an association between the low visual P300 trajectory with high familial risk in male offspring. This association was detected in offspring in the 8-12 age range, but not in 13-18 or 19-29 year olds or in high-risk female offspring. CHRM2 association analysis with P300 finds 8-12 year olds who are homozygous for the T allele of rs1824024 are 2.6 times more likely to follow a P300 trajectory characterized by lower and slower change regardless of familial loading. Combining the odds for being male and having a TT genotype results in odds of 6.5 that individuals will follow the low P300 trajectory.