Indole-3-Propionic Acid, a Functional Metabolite of Clostridium sporogenes, Promotes Muscle Tissue Development and Reduces Muscle Cell Inflammation

Abstract

Clostridium sporogenes (C. sporogenes), as a potential probiotic, metabolizes tryptophan and produces an anti-inflammatory metabolite, indole-3-propionic acid (IPA). Herein, we studied the effects of C. sporogenes and its bioactive metabolite, IPA, on skeletal muscle development and chronic inflammation in mice. In the in vivo study, the muscle tissues and serum samples of mice with C. sporogenes supplementation were used to analyze the effects of C. sporogenes on muscle metabolism; the IPA content was determined by metabonomics and ELISA. In an in vitro study, C2C12 cells were exposed to lipopolysaccharide (LPS) alone or LPS + IPA to verify the effect of IPA on muscle cell inflammation by transcriptome, and the involved mechanism was revealed by different functional assays. We observed that C. sporogenes colonization significantly increased the body weight and muscle weight gain, as well as the myogenic regulatory factors’ (MRFs) expression. In addition, C. sporogenes significantly improved host IPA content and decreased pro-inflammatory cytokine levels in the muscle tissue of mice. Subsequently, we confirmed that IPA promoted C2C12 cells’ proliferation by activating MRF signaling. IPA also effectively protected against LPS-induced C2C12 cells inflammation by activating Pregnane X Receptor and restoring the inhibited miR-26a-2-3p expression. miR-26a-2-3p serves as a novel muscle inflammation regulatory factor that could directly bind to the 3′-UTR of IL-1β, a key initiator factor in inflammation. The results suggested that C. sporogenes with its functional metabolite IPA not only helps muscle growth development, but also protects against inflammation, partly by the IPA/ miR-26a-2-3p /IL-1β cascade.

Sepsis-Induced Gut Dysbiosis Mediates the Susceptibility to Sepsis-Associated Encephalopathy in Mice

“…These studies indicate the protective effect of IPA against neuronal inflammation, which prompted us to select IPA from the metabolites enriched in SER feces as a possible protective substance against SAE. Consistent with previous findings ( 29 , 32 ), we also observed a beneficial role for IPA in SAE, which was related to its anti-inflammatory effects. In the present study, the direct effect of IPA on microglia may be responsible for the reduction in neuroinflammation after IPA treatment.…”

Biological Effects of Indole-3-Propionic Acid, a Gut Microbiota-Derived Metabolite, and Its Precursor Tryptophan in Mammals’ Health and Disease

“…Moreover, IPA acts as a ligand of the aryl hydrocarbon receptor (AhR) present in colonic epithelial cells, activation of which is associated with anti-inflammatory and anticancer effects [119] Interestingly, it has been observed that in patients suffering from colitis serum, IPA concentration decreases significantly [28]. Apart from being an AhR ligand, IPA can also produce its biological action by activating the pregnane X receptor (PXR) present in colonic, liver endothelial and muscle cells [23,119,120]. Complex laboratory techniques allow testing the function of GBB by measuring its permeability to specific substances, including Fluorescein Isothiocyanate-Dextran (FITC-Dextran).…”

“…Interestingly, IPA protects cells from ROS [25,128,129], oxidative damage and lipid peroxidation caused by potassium bromate [130][131][132], potassium iodate [24], iron (II) sulphate [133,134], iron (III) chloride [135], chromium (III) chloride [136], and 2,2 -Azino-bis(3-ethylbenzothiazoline-6sulfonic acid (ABTS) [137]. Additionally, IPA decreases the expression of proinflammatory cytokines, including TNF-α [22,27,121], IL-1β [23,27], IL-6 [27], IL-12 [22], IL-13 [22] and MCP-1 [22,82]. Interestingly, IPA also shows antimicrobial activity by inhibiting the growth of Legionella pneumophila [138,139], and Salmonella typhimurium [140].…”

“…Scientific papers evaluating the biological effects of this metabolite have multiplied greatly over the past few years [19][20][21][22]. IPA has a protective role on a cellular and tissue level, by limiting inflammation [23], lipid peroxidation [24], and the formation of free radicals [25]. Additionally, IPA affects the function of the immune [22], nervous [26], gastrointestinal [27] and cardiovascular system [19], and its synthesis decreases significantly in several pathogenic states and diseases, including colitis [28], diabetes [29], and obesity [30].…”

Heterologous Expression of NoxA Confers Aerotolerance in Clostridium sporogenes

“…Oxygen tolerance in Clostridia may also be beneficial in biomanufacturing, where these strains are used in a number of processes, such as ABE fermentation (focused on C. acetobutylicum) and other bioproduction systems for chemicals and fuels (Moon et al, 2016;Zeng, 2019;Zhao et al, 2020). Focusing specifically on C. sporogenes, this strain has been used for non-acetone forming butanol production from rice straw (Gottumukkala et al, 2013(Gottumukkala et al, , 2015 and has recently been identified as a producer of the potent antioxidant 3-indolepropionic acid (IPA) (Du et al, 2021), which has neuroprotective properties (Zhang and Davies, 2016). The use of Clostridium has been limited in these contexts due to the requirement of an oxygen-free environment.…”