Genetic association between major depressive disorder and type 2 diabetes mellitus: Shared pathways and protein networks

Unlocking Therapeutic Synergy: Tailoring Drugs for Comorbidities such as Depression and Diabetes through Identical Molecular Targets in Different Cell Types

Research in the field of pharmacology aims to generate new treatments for pathologies. Nowadays, there are an increased number of chronic disorders that severely and durably handicap many patients. Among the most widespread pathologies, obesity, which is often associated with diabetes, is constantly increasing in incidence, and in parallel, neurodegenerative and mood disorders are increasingly affecting many people. For years, these pathologies have been so frequently observed in the population in a concomitant way that they are considered as comorbidities. In fact, common mechanisms are certainly at work in the etiology of these pathologies. The main purpose of this review is to show the value of anticipating the effect of baseline treatment of a condition on its comorbidity in order to obtain concomitant positive actions. One of the implications would be that by understanding and targeting shared molecular mechanisms underlying these conditions, it may be possible to tailor drugs that address both simultaneously. To this end, we firstly remind readers of the close link existing between depression and diabetes and secondly address the potential benefit of the pleiotropic actions of two major active molecules used to treat central and peripheral disorders, first a serotonin reuptake inhibitor (Prozac ®) and then GLP-1R agonists. In the second part, by discussing the therapeutic potential of new experimental antidepressant molecules, we will support the concept that a better understanding of the intracellular signaling pathways targeted by pharmacological agents could lead to future synergistic treatments targeting solely positive effects for comorbidities.

Prevalence and factors associated with metabolic syndrome in first hospitalization for major depression disorder patients

Major depressive disorder (MDD) is a common and socially burdensome psychiatric disorder with a causal and complex relationship with metabolic syndrome (MetS), which is often co-morbid. However, the prevalence and risk factors for MetS in patients with MDD are inconclusive. The purpose of this study is to investigate the prevalence and factors influencing MetS in first hospitalization MDD patients. A total of 981 MDD patients were included. Sociodemographic and general clinical data were collected from the patients, while metabolism-related parameters were also measured, and psychological symptoms were assessed. Our study found that the prevalence of MetS in the study population was 9.68%. MDD patients with MetS had higher levels of metabolism-related parameters and more severe psychological symptoms. We identified risk factors for MetS and its severity separately: age of onset of MDD, more severe depressive symptoms, and higher thyroid stimulating hormone (TSH) levels were risk factors for the development of MetS, whereas higher TSH levels were risk factors for the severity of MetS. Our results suggest that MetS is not highly prevalent in MDD patients, but certain risk factors may increase its likelihood and severity, and that these findings could be beneficial for clinical intervention and care of MetS.

Genetic association between ankylosing spondylitis and major depressive disorders: Shared pathways, protein networks and the key gene

The prevalence of ankylosing spondylitis (AS) and major depressive disorders (MDD) becomes increasingly pronounced, exerting a significant impact on the life quality of contemporary people. Although there is mounting evidence of a link between AS and major depression disorders, the specific interactions between the two have not been thoroughly investigated. To this end, this study aimed to check whether the gene expression profiles of patients with AS and major depression disorders overlapped, and whether there were any functional links between the identified genes via protein-protein interactions. Herein, the relationship between the 4 datasets (GSE73754, GSE98793, GSE25101, and GSE54564) chosen from the Gene Expression Omnibus for evaluation and validation was investigated using gene characterization and functional enrichment. Then, following Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes that explore the biological processes of common genes and demonstrate the interrelationships between common genes, hub genes were obtained using the STRING database and the application cytoHubba plugin of Cytoscape software. The correlation between the gene and 22 types of immuno-infiltrating cells was explored, and the key gene as well as the diagnostic efficiency of the key gene was obtained through verification. A total of 204 shared genes were discovered, the majority of which were functionally enriched in Ribosome, Coronavirus disease COVID19, Starch and sucrose metabolism, and Galactose metabolism. Then, efforts were made to go through STRING. Immuno-infiltration studies revealed that Neutrophils, T cells CD8, T cells CD4 naive, T cells CD4 memory resting, T cells CD4 memory activated, and T cells regulatory were associated with the pathogenesis of AS and MDD. Additionally, the receiver operating characteristic curve revealed that the key gene MRPL13 played diagnostic roles in AS and MDD after intersecting 10 hub genes with 37 differential expression genes from the 2 validation datasets. The obtained results suggest an overlapping genetic structure between AS and major depression disorders. MRPL13 may provide key insights into the relationship between AS and MDD.

Brain structural and functional alterations in individuals with combined overweight/obesity and mood disorders: A systematic review of neuroimaging studies

Growing evidence suggests there is a bidirectional relationship between depression and obesity, which are associated with structural and functional brain abnormalities. However, the underlying neurobiological mechanisms subserving the foregoing associations have yet to be characterized. It is necessary to summarize the neuroplastic brain changes in relation to depression and obesity. We systematically searched articles from 1990 to November 2022 on databases including MEDLINE/PubMed, Web of Science, PsycINFO. Only neuroimaging studies within the scope of potential differences in brain function and structure in individuals with depression and obesity/ BMI changes were included. Twenty-four eligible studies were included in the review herein, consisting of 17 studies reporting changes in brain structure, 4 studies reporting abnormal brain function, and 3 studies reporting both changes in brain structure and function. Results indicated an interaction between depression and obesity on brain functions, and their influence on brain structure is both extensive and specific. Overall, reduced whole brain, intracranial, and gray matter volume (e.g. frontal, temporal gyri, thalamic, and hippocampal) and impaired white matter integrity was observed in persons with depression and obesity comorbidity. Additional evidence on resting state fMRI reveals select brain regions associated with cognitive control, emotion regulation, and reward functions. Due to the diversity of tasks in task fMRI, the distinct neural activation patterns are revealed separately. The bidirectional relationship between depression and obesity reflects different characteristics in brain structure and function. Longitudinal designs should be reinforced in follow-up studies.

Genetic variations in the retrograde endocannabinoid signaling pathway in Chinese patients with major depressive disorder

Background

The retrograde endocannabinoid (eCB) pathway is closely associated with the etiology of major depressive disorder (MDD) at both pathophysiological and genetic levels. This study aimed to investigate the potential role of genetic mutations in the eCB pathway and underlying mechanisms in Han Chinese patients with MDD.

Methods

A total of 96 drug-naïve patients with first-episode MDD and 62 healthy controls (HCs) were recruited. Whole-exome sequencing was performed to identify the gene mutation profiles in patients with MDD. Results were filtered to focus on low-frequency variants and rare mutations (minor allele frequencies <0.05) related to depressive phenotypes. Enrichment analyses were performed for 146 selected genes to examine the pathways in which the most significant enrichment occurred. A protein-protein interaction (PPI) network analysis was performed to explore the biological functions of the eCB pathway. Finally, based on current literature, a preliminary analysis was conducted to explore the effect of genetic mutations on the function of this pathway.

Results

Our analysis identified 146 (15.02%) depression-related genetic mutations in patients with MDD when compared with HCs, and 37 of the mutations were enriched in the retrograde eCB signaling pathway. Seven hub genes in the eCB pathway were closely related to mitochondrial function, including Complex I genes (NDUFS4, NDUFV2, NDUFA2, NDUFA12, NDUFB11) and genes associated with protein (PARK7) and enzyme (DLD) function in the regulation of mitochondrial oxidative stress.

Conclusion

These results indicate that genetic mutations in the retrograde eCB pathway represent potential etiological factors associated with the pathogenesis of MDD.

Association of metformin and depression in patients with type 2 diabetes

BACKGROUND

Emerging evidence showed metformin may have pleiotropic effects on ameliorating depression. However, whether metformin was associated with decreased risk of depression remains unclear.

METHODS

A historical cohort study was conducted based on a medical claim database from 2010 to 2017 in Beijing, China. Patients newly diagnosed with T2D were classified into the metformin and non-metformin groups according to their initial antidiabetic prescription. The incidences of depression between the groups were compared using Cox proportional regression model.

RESULTS

There were 193,624 (37.4 %) and 323,930 (62.6 %) T2D patients in the metformin and non-metformin groups. The mean age was 54.9 (SD: 13.1) years and 53.9% were females. With a median follow-up of 3.2 years, 64,963 patients developed depression. The adjusted incidence of depression in the metformin group (30.6, 95 % CI: 30.1, 31.0 per 1000 person-years) was significantly lower than in the non-metformin group (39.6, 95 % CI: 39.3, 40.0 per 1000 person-years, P < 0.001). The metformin group was significantly associated with a lower risk of depression compared with the overall non-metformin group (HR: 0.77, 95% CI: 0.75, 0.78), as well as compared with α-glucosidase inhibitors (HR: 0.73, 95 % CI: 0.71, 0.74), sulfonylureas (HR: 0.84, 95 % CI: 0.82, 0.86), and glinides (HR: 0.85, 95 % CI: 0.82, 0.88), except for thiazolidinediones (HR: 0.96, 95 % CI: 0.91, 1.01). The association between metformin and lower depression risk was significant in all the age and sex subgroups.

CONCLUSIONS

Metformin was associated with a lower risk of depression compared with other oral hypoglycemic agents, indicating a potential pleiotropic effect on depression.