Evaluation of the Genetic Association Between Adult Obesity and Neuropsychiatric Disease

Shared genetics between classes of obesity and psychiatric disorders: A large-scale genome-wide cross-trait analysis

AIMS

Epidemiological studies demonstrate an association between classes of obesity and psychiatric disorders, although little is known about shared genetics and causality of association. Thus, we aimed to investigate shared genetics and causal link between different classes of obesity and psychiatric disorders.

METHODS

We used genome-wide association study (GWAS) summary data range from 9725 to 500,199 sample sizes of European descent, conducted a large-scale genome-wide cross-trait association study to investigate genetic overlap between the classes of obesity and anorexia nervosa, attention-deficit/hyperactivity disorder, autism spectrum disorder, bipolar disorder, major depressive disorder, obsessive-compulsive disorder, schizophrenia, anxiety disorders and Tourette syndrome. We conducted transcriptome-wide association study analysis (TWAS) to identified variants regulated gene expression in those related disorders. Finally, pathway enrichment analysis to identified major pathways.

RESULTS

In the combined analysis, we replicated 211 previously reported loci and discovered 58 novel independent loci that were associated with all three classes of obesity and related psychiatric disorders. Functional analysis revealed that the identified variants regulated gene expression in major tissues belonging to exocrine/endocrine, digestive, circulatory, adipose, digestive, respiratory, and nervous systems, such as DCC, NEGR1, INO80E. Mendelian randomization analyses suggested that there may be a two-way or one-way causal relationship between obesity and psychiatric disorders.

CONCLUSION

This large-scale genome-wide cross-trait analysis identified shared genetics and potential causal links between classes of obesity and psychiatric disorders (attention deficit hyperactivity disorder, autism spectrum disorder, anorexia nervosa, major depressive disorder, schizophrenia, and obsessive-compulsive disorder). Such shared genetics suggests potential new biological functions in common among them.

Clinical Characterization of Copy Number Variants Associated With Neurodevelopmental Disorders in a Large-scale Multiancestry Biobank

IMPORTANCE

Past studies identified rare copy number variants (CNVs) as risk factors for neurodevelopmental disorders (NDDs), including autism spectrum disorder and schizophrenia. However, the clinical characterization of NDD CNVs is understudied in population cohorts unselected for neuropsychiatric disorders and in cohorts of diverse ancestry.

OBJECTIVE

To identify individuals harboring NDD CNVs in a multiancestry biobank and to query their enrichment for select neuropsychiatric disorders as well as association with multiple medical disorders.

DESIGN, SETTINGS, AND PARTICIPANTS

In a series of phenotypic enrichment and association analyses, NDD CNVs were clinically characterized among 24 877 participants in the BioMe biobank, an electronic health record-linked biobank derived from the Mount Sinai Health System, New York, New York. Participants were recruited into the biobank since September 2007 across diverse ancestry and medical and neuropsychiatric specialties. For the current analyses, electronic health record data were analyzed from May 2004 through May 2019.

MAIN OUTCOMES AND MEASURES

NDD CNVs were identified using a consensus of 2 CNV calling algorithms, based on whole-exome sequencing and genotype array data, followed by novel in-silico clinical assessments.

RESULTS

Of 24 877 participants, 14 586 (58.7%) were female; self-reported ancestry categories included 5965 (24.0%) who were of African ancestry, 7892 (31.7%) who were of European ancestry, and 8536 (34.3%) who were of Hispanic ancestry; and the mean (SD) age was 50.5 (17.3) years. Among 24 877 individuals, the prevalence of 64 NDD CNVs was 2.5% (n = 627), with prevalence varying by locus, corroborating the presence of some relatively highly prevalent NDD CNVs (eg, 15q11.2 deletion/duplication). An aggregate set of NDD CNVs were enriched for congenital disorders (odds ratio, 2.0; 95% CI, 1.1-3.5; P = .01) and major depressive disorder (odds ratio, 1.5; 95% CI, 1.1-2.0; P = .01). In a meta-analysis of medical diagnoses (n = 195 hierarchically clustered diagnostic codes), NDD CNVs were significantly associated with several medical outcomes, including essential hypertension (z score = 3.6; P = 2.8 × 10-4), kidney failure (z score = 3.3; P = 1.1 × 10-3), and obstructive sleep apnea (z score = 3.4; P = 8.1 × 10-4) and, in another analysis, morbid obesity (z score = 3.8; P = 1.3 × 10-4). Further, NDD CNVs were associated with increased body mass index in a multiancestry analysis (β = 0.19; 95% CI, 0.10-0.31; P = .003). For 36 common serum tests, there was no association with NDD CNVs.

CONCLUSIONS AND RELEVANCE

Clinical features of individuals harboring NDD CNVs were elucidated in a large-scale, multiancestry biobank, identifying enrichments for congenital disorders and major depressive disorder as well as associations with several medical outcomes, including hypertension, kidney failure, and obesity and obesity-related phenotypes, specifically obstructive sleep apnea and increased body mass index. The association between NDD CNVs and obesity outcomes indicate further potential pleiotropy of NDD CNVs beyond neurodevelopmental outcomes previously reported. Future clinical genetic investigations may lead to insights of at-risk individuals and therapeutic strategies targeting specific genetic variants. The importance of diverse inclusion within biobanks and considering the effect of rare genetic variants in a multiancestry context is evident.

SNAP25 mutation disrupts metabolic homeostasis, steroid hormone production and central neurobehavior

OBJECTIVE

SNAP-25 is one of the key proteins involved in formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes that are at the core of hormonal secretion and synaptic transmission. Altered expression or function of SNAP-25 can contribute to the development of neuropsychiatric and metabolic disease. A dominant negative (DN) I67T missense mutation in the b-isoform of SNAP-25 (DN-SNAP25mut) mice leads to abnormal interactions within the SNARE complex and impaired exocytotic vesicle recycling, yet the significance of this mutation to any association between the central nervous system and metabolic homeostasis is unknown.

METHODS

Here we explored aspects of metabolism, steroid hormone production and neurobehavior of DN-SNAP25mut mice.

RESULTS

DN-SNAP25mut mice displayed enhanced insulin function through increased Akt phosphorylation, alongside increased adrenal and gonadal hormone production. In addition, increased anxiety behavior and beigeing of white adipose tissue with increased energy expenditure were observed in mutants.

CONCLUSIONS

Our results show that SNAP25 plays an important role in bridging central neurological systems with peripheral metabolic homeostasis, and provide potential insights between metabolic disease and neuropsychiatric disorders in humans.

Obesity as a multisystem disease: Trends in obesity rates and obesity-related complications

Obesity is a chronic multisystem disease associated with increased morbidity and mortality. The increasing prevalence of obesity makes it a major healthcare challenge across both developed and developing countries. Traditional measures such as body mass index do not always identify individuals at increased risk of comorbidities, yet continue to be used in deciding who qualifies for weight loss treatment. A better understanding of how obesity is associated with comorbidities, in particular non-metabolic conditions, is needed to identify individuals at risk in order to prioritize treatment. For metabolic disorders such as type 2 diabetes (T2D), weight loss can prevent T2D in individuals with prediabetes. It can improve and reverse T2D if weight loss is achieved early in the course of the disease. However, access to effective weight loss treatments is a significant barrier to improved health for people with obesity. In the present paper, we review the rising prevalence of obesity and why it should be classed as a multisystem disease. We will discuss potential mechanisms underlying its association with various comorbidities and how these respond to treatment, with a particular focus on cardiometabolic disease, malignancy and mental health.

Intersections in Neuropsychiatric and Metabolic Disorders: Possible Role of TRPA1 Channels

Neuropsychiatric disorders (NPDs) are a huge burden to the patient, their family, and society. NPDs have been greatly associated with cardio-metabolic comorbidities such as obesity, type-2 diabetes mellitus, dysglycaemia, insulin resistance, dyslipidemia, atherosclerosis, and other cardiovascular disorders. Antipsychotics, which are frontline drugs in the treatment of schizophrenia and off-label use in other NPDs, also add to this burden by causing severe metabolic perturbations. Despite decades of research, the mechanism deciphering the link between neuropsychiatric and metabolic disorders is still unclear. In recent years, transient receptor potential Ankyrin 1 (TRPA1) channel has emerged as a potential therapeutic target for modulators. TRPA1 agonists/antagonists have shown efficacy in both neuropsychiatric disorders and appetite regulation and thus provide a crucial link between both. TRPA1 channels are activated by compounds such as cinnamaldehyde, allyl isothiocyanate, allicin and methyl syringate, which are present naturally in food items such as cinnamon, wasabi, mustard, garlic, etc. As these are present in many daily food items, it could also improve patient compliance and reduce the patients' monetary burden. In this review, we have tried to present evidence of the possible involvement of TRPA1 channels in neuropsychiatric and metabolic disorders and a possible hint towards using TRPA1 modulators to target appetite, lipid metabolism, glucose and insulin homeostasis and inflammation associated with NPDs.

The potential of artemisinins as anti-obesity agents via modulating the immune system

Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed.