Comparative metaproteomics analysis shows altered fecal microbiota signatures in patients with major depressive disorder

Abstract

Major depressive disorder (MDD) is a highly prevalent and debilitating mental illness, which is associated with disorder of gut microbiota. However, few studies focusing on detection of the signatures of bacteria in feces of MDD patients using proteomics approach have been carried out. Here, a comparative metaproteomics analysis on the basis of an isobaric tag for relative and absolute quantification coupled with tandem mass spectrometry was carried out to explore the signature of gut microbiota in patients with MDD. Ten patients (age: 18-56 years, five women) who had MDD and a score over 20 on the Hamilton's Depression Scale and 10 healthy controls (age: 24-65 years, five women) group matched for sex, age, and BMI were enrolled. As a result, 279 significantly differentiated bacterial proteins (P<0.05) were detected and used for further bioinformatic analysis. According to phylogenetic analysis, statistically significant differences were observed for four phyla: Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria (P<0.05, for each). Abundances of 16 bacterial families were significantly different between the MDD and healthy controls (P<0.05). Furthermore, Cluster of Orthologous Groups analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that disordered metabolic pathways of bacterial proteins were mainly involved in glucose metabolism and amino acid metabolism. In conclusion, fecal microbiota signatures were altered significantly in MDD patients. Our findings provide a novel insight into the potential connection between gut microbiota and depression.

The Microbiota‐Inflammasome Hypothesis of Major Depression

“…Other authors have reported a decrease of this genus after antidepressant intervention, suggesting that Colinsella might represent a useful index for MDD management and treatment . Another study in a small cohort from the same group reported partly contrasting findings, given that Firmicutes, Actinobacteria, and Lachnospiraceae were increased in MDD patients, while Bacteroidetes and Proteobacteria were reduced . The authors concluded that such differences might have stemmed form different sample size, demographics, and statistical approach …”

Microbiota-Orientated Treatments for Major Depression and Schizophrenia

“…We have published a meta-analysis suggesting that patients with irritable bowel syndrome were at higher risk of major depression [37], confirming the potential causal or bilateral relationship between microbiota disturbances and major depression. Several studies have shown microbiota disturbances in patients with major depression; these disturbances are summarized in Table 1 [38][39][40][41][42][43][44][45][46][47][48][49][50]. Probiotics yielded small but significant effects for depression (d = −0.24, p < 0.01) and anxiety (d = −0.10, p = 0.03).…”

Antidepressant treatment with fluoxetine during pregnancy and lactation modulates the gut microbiome and metabolome in a rat model relevant to depression

“…Correspondingly, in vitro studies have shown that serotonin affects the growth of microbes such as Escherichia coli and Rhodospirillum rubrum, 8 and activates bacterial quorum sensing. 9 Several studies have found alterations in the gut microbiota composition of patients with major depression [10][11][12][13][14][15][16] and rodents with depressive-like symptoms. [17][18][19][20][21] Moreover, recent human population-based studies, 16,22,23 as well as rodent experiments, [24][25][26][27][28][29] showed that SSRIs modulate the gut microbiota composition, an effect that may be related to their in vitro antimicrobial properties.…”