The Putative Antidepressant Mechanisms of Probiotic Bacteria: Relevant Genes and Proteins

Abstract

Probiotic bacteria are widely accepted as therapeutic agents against inflammatory bowel diseases for their immunostimulating effects. In the last decade, more evidence has emerged supporting the positive effects of probiotics on the course of neurodegenerative and psychiatric diseases. This brief review summarizes the data from clinical studies of probiotics possessing antidepressant properties and focuses on the potential genes and proteins underlying these mechanisms. Data from small-sample placebo-controlled pilot studies indicate that certain strains of bacteria can significantly reduce the symptoms of depression, especially in depressed patients. Despite the disparity between studies attempting to pinpoint the bacterial putative genes and proteins accounting for these mechanisms, they ultimately show that bacteria are a potential source of metabiotics—microbial metabolites or structural components. Since the constituents of cells—namely, secreted proteins, peptides and cell wall components—are most likely to be entangled in the gut–brain axis, they can serve as starting point in the search for probiotics with concrete properties.

Biomarkers and Utility of the Antioxidant Potential of Probiotic Lactobacilli and Bifidobacteria as Representatives of the Human Gut Microbiota

“…These are known today as postbiotics, which are defined as metabolites and cell components conferring health benefits [215,216]. Postbiotics are a promising field of research for future pharmaceuticals and functional foods possessing antioxidant properties for the treatment of depressive disorders [217]. The potential of postbiotics can be harnessed by packing them into nanostructures, allowing them to be delivered to organs affected by inflammation [218].…”

Common Inflammatory Mechanisms in COVID-19 and Parkinson’s Diseases: The Role of Microbiome, Pharmabiotics and Postbiotics in Their Prevention

“…Analysis of the state of the microbiome is an important biomarker of the state of the immune and nervous system and susceptibility to neurological and infectious diseases as COVID-19. 32,393,394 The intestinal microbiome influences the host organism due to its ability to synthesize various biologically active compounds. The whole system functions as a single network.…”

The Role of the PFNA Operon of Bifidobacteria in the Recognition of Host’s Immune Signals: Prospects for the Use of the FN3 Protein in the Treatment of COVID-19

“…Monoclonal antibodies-based treatments against pro-inflammatory cytokines are known for their infamous side effects [123]. Bifidobacteria, which are known for their anti-inflammatory properties, might be a better substitute [36][37][38]. Pharmacological components of bifidobacteria named postbiotics, which the FN3 protein, are another exciting area of research fueling antiviral drug development.…”

“…The immunomodulatory properties of bifidobacteria are already being used in the complex therapy of various diseases, including cancer [33], lung disease [34], and gastrointestinal diseases [35]. In recent years, a few reviews have scrutinized the role of bifidobacteria and probiotics containing them in modulating the host's immune system [36][37][38]. This review discusses the bifidobacterial genes and their products involved in immune regulation in humans with a focus on the recently discovered PFNA operon.…”