The Modulatory Effect of Sodium Propionate Treatment in the Expression of Inflammatory Cytokines and Intracellular Growth of Brucella abortus 544 in Raw 264.7 Cells

In this study, we investigated the effects of sodium propionate (SP) treatment on intracellular mechanism of murine macrophages and its contribution to host immunity during Brucella abortus 544 infection. The intracellular growth assay revealed that SP inhibited Brucella replication inside the macrophages. To determine intracellular signaling involved during SP treatment after Brucella infection, we analyzed the change of five different cytokines production relevant to SP such as TNF-α, IL-10, IFN-γ, IL-1β, and IL-6, and the results indicated that the boost with IL-10 was apparent throughout the culture period for 48 h as well as IL-1β which was apparent at 24 h post-infection and IFN-γ which was apparent at 24 h and 48 h in comparison to SP untreated groups. On the other way, SP-treated cells displayed suppressed production of TNF-α and IL-6 at all time points tested and 48 h post-infection, respectively. Furthermore, we conducted western blot to establish a cellular mechanism, and the result suggested that SP treatment attenuated p50 phosphorylation, part of the NF-κB pathway. These findings indicated that the inhibitory effect of SP against Brucella infection could be attributed through induction of cytokine production and interference on intracellular pathway, suggesting SP as a potential candidate for treating brucellosis.

Sodium Propionate Relieves LPS-Induced Inflammation by Suppressing the NF-ĸB and MAPK Signaling Pathways in Rumen Epithelial Cells of Holstein Cows

Subacute ruminal acidosis (SARA) is a prevalent disease in intensive dairy farming, and the rumen environment of diseased cows acidifies, leading to the rupture of gram-negative bacteria to release lipopolysaccharide (LPS). LPS can cause rumentitis and other complications, such as liver abscess, mastitis and laminitis. Propionate, commonly used in the dairy industry as a feed additive, has anti-inflammatory effects, but its mechanism is unclear. This study aims to investigate whether sodium propionate (SP) reduces LPS-induced inflammation in rumen epithelial cells (RECs) and the underlying mechanism. RECs were stimulated with different time (0, 1, 3, 6, 9, 18 h) and different concentrations of LPS (0, 1, 5, 10 μg/mL) to establish an inflammation model. Then, RECs were treated with SP (15, 25, 35 mM) or 10 μM PDTC in advance and stimulated by LPS for the assessment. The results showed that LPS (6h and 10 μg/mL) could stimulate the phosphorylation of NF-κB p65, IκB, JNK, ERK and p38 MAPK through TLR4, and increase the release of TNF-α, IL-1β and IL-6. SP (35 mM) can reduce the expression of cytokines by effectively inhibiting the NF-κB and MAPK inflammatory pathways. This study confirmed that SP inhibited LPS-induced inflammatory responses through NF-κB and MAPK in RECs, providing potential therapeutic targets and drugs for the prevention and treatment of SARA.

Sodium propionate improves rheumatoid arthritis by inhibiting survivin mediated proliferation of fibroblast like synoviocytes by promoting miR-140-5p

BACKGROUND

Increased proliferation and impaired death of fibroblast-like synovial cells play an important role in the development of rheumatoid arthritis (RA). Survivin plays an important role in the prodromal stage and prognosis of RA and has been introduced as a biomarker of joint injury in RA patients. The purpose of this study was to explore whether propionate alleviates RA through miR-140-5p/survivin pathway.

METHODS

The synovial tissues of RA patients were collected to detect the expression levels of miR-140-5p and survivin; normal human fibroblast-like synovial cells (HLSs) and RA fibroblast-like synovial cells (RA-FLSs) were cultured and treated with 10 mM of sodium propionate (SP), then the expressions of miR-140-5p and survivin, cell viability and apoptosis were detected; collagen induced arthritis (CIA) rat model was constructed and treated with SP, then the tissue inflammation level and the expression levels of miR-140-5p and Survivin were detected.

RESULTS

The expression of miR-140-5p decreased in synovial tissues of RA patients and RA-FLSs cells, while the expression of survivin increased significantly in RA patients. SP promoted miR-140-5p expression and apoptosis in RA-FLSs cells and inhibited survivin expression and cell viability of RA-FLSs cells. In addition, miR-140-5p plays a protective role by targeting survivin. Importantly, in the CIA rat model, SP reduced joint inflammatory response, and the miR-140-5p inhibitor weakened the protective effect of SP.

CONCLUSION

SP can alleviate RA by promoting the expression of miR-140-5p and inhibiting the excessive proliferation and death impairment of RA-FLSs cells induced by survivin.

SCFA Treatment Alleviates Pathological Signs of Migraine and Related Intestinal Alterations in a Mouse Model of NTG-Induced Migraine

Background: There is a growing realization that the gut–brain axis signaling is critical for maintaining the health and homeostasis of the Central Nervous System (CNS) and the intestinal environment. The role of Short-Chain Fatty Acids (SCFAs), such as Sodium Propionate (SP) and Sodium Butyrate (SB), has been reported to counteract inflammation activation in the central and Enteric Nervous System (ENS). Methods: In this study, we evaluated the role of the SCFAs in regulating the pathophysiology of migraine and correlated dysregulations in the gut environment in a mouse model of Nitroglycerine (NTG)-induced migraine. Results: We showed that, following behavioral tests evaluating pain and photophobia, the SP and SB treatments attenuated pain attacks provoked by NTG. Moreover, treatments with both SCFAs reduced histological damage in the trigeminal nerve nucleus and decreased the expression of proinflammatory mediators. Ileum evaluation following NTG injection reported that SCFA treatments importantly restored intestinal mucosa alterations, as well as the release of neurotransmitters in the ENS. Conclusions: Taken together, these results provide evidence that SCFAs exert powerful effects, preventing inflammation through the gut–brain axis, suggesting a new insight into the potential application of SCFAs as novel supportive therapies for migraine and correlated intestinal alterations.

Sodium propionate exerts anticancer effect in mice bearing breast cancer cell xenograft by regulating JAK2/STAT3/ROS/p38 MAPK signaling

Propionate is a short-chain fatty acid (SCFA) mainly produced from carbohydrates by gut microbiota. Sodium propionate (SP) has shown to suppress the invasion in G protein-coupled receptor 41 (GPR41) and GPR43-overexpressing breast cancer cells. In this study we investigated the effects of SP on the proliferation, apoptosis, autophagy, and antioxidant production of breast cancer cells. We showed that SP (5-20 mM) dose-dependently inhibited proliferation and induced apoptosis in breast cancer cell lines JIMT-1 (ER-negative and HER2-expressing) and MCF7 (ER-positive type), and this effect was not affected by PTX, thus not mediated by the GPR41 or GPR43 SCFA receptors. Meanwhile, we demonstrated that SP treatment increased autophagic and antioxidant activity in JIMT-1 and MCF7 breast cancer cells, which might be a compensatory mechanism to overcome SP-induced apoptosis, but were not sufficient to overcome SP-mediated suppression of proliferation and induction of apoptosis. We revealed that the anticancer effect of SP was mediated by inhibiting JAK2/STAT3 signaling which led to cell-cycle arrest at G0/G1 phase, and increasing levels of ROS and phosphorylation of p38 MAPK which induced apoptosis. In nude mice bearing JIMT-1 and MCF7 cells xenograft, administration of SP (20 mg/mL in drinking water) significantly suppressed tumor growth by regulating STAT3 and p38 in tumor tissues. These results suggest that SP suppresses proliferation and induces apoptosis in breast cancer cells by inhibiting STAT3, increasing the ROS level and activating p38. Therefore, SP is a candidate therapeutic agent for breast cancer.

Sodium Propionate Enhances Nrf2-Mediated Protective Defense Against Oxidative Stress and Inflammation in Lipopolysaccharide-Induced Neonatal Mice

Background

Alveolar arrest and the impaired angiogenesis caused by chronic inflammation and oxidative stress are two main factors in bronchopulmonary dysplasia (BPD). Short-chain fatty acids (SCFAs), especially propionate, possess anti-oxidant and anti-inflammatory effects. The present study was designed to examine the roles of sodium propionate (SP) on lipopolysaccharide (LPS)-challenged BPD and its potential mechanisms.

Methods

WT, Nrf2^-/- mice and pulmonary microvascular endothelial cells (HPMECs) were used in this study. LPS was performed to mimic BPD model both in vivo and vitro. Lung histopathology, inflammation and oxidative stress-related mRNA expressions in lungs involved in BPD pathogenesis were investigated. In addition, cell viability and angiogenesis were also tested.

Results

The increased nuclear factor erythroid 2-related factor (Nrf2) and decreased Kelch-like ECH-associated protein-1 (Keap-1) expressions were observed after SP treatment in the LPS-induced neonatal mouse model of BPD. In LPS-induced wild-type but not Nrf2^-/- neonatal mice, SP reduced pulmonary inflammation and oxidative stress and exhibited obvious pathological alterations of the alveoli. Moreover, in LPS-evoked HPMECs, SP accelerated Nrf2 nuclear translocation presented and exhibited cytoprotective and pro-angiogenesis effects. In addition, SP diminished the LPS-induced inflammatory response by blocking the activation of nuclear factor-kappa B pathway. Moreover, pretreatment with ML385, an Nrf2 specific inhibitor, offsets the beneficial effects of SP on inflammation, oxidative stress and angiogenesis in LPS-evoked HPMECs.

Conclusion

SP protects against LPS-induced lung alveolar simplification and abnormal angiogenesis in neonatal mice and HPMECs in an Nrf2-dependent manner.

Supplementing the Diet with Sodium Propionate Suppresses the Severity of Viral Immuno-inflammatory Lesions

This report evaluates a dietary manipulation approach to suppress the severity of ocular infections caused by herpes simplex virus infection. The virus causes chronic damage to the cornea that results from a T-cell-orchestrated inflammatory reaction to the infection. Lesion severity can be limited if cells with regulatory activity predominate over proinflammatory T cells and nonlymphoid inflammatory cells. In this report, we show that this outcome can be achieved by including the short-chain fatty acid (SCFA) salt sodium propionate (SP) in the drinking water. Animals given the SP supplement developed significantly fewer ocular lesions than those receiving no supplement. Corneas and lymphoid organs contained fewer CD4 Th1 and Th17 T cells, neutrophils, and macrophages than those of controls, but a higher frequency of regulatory T cells (Treg) was present. The inclusion of SP in cultures to induce CD4 T cell subsets in vitro reduced the magnitude of Th1 and Th17 responses but expanded Treg induction. Dietary manipulation was an effective approach to limit the severity of viral immuno-inflammatory lesions and may be worth exploring as a means to reduce the impact of herpetic lesions in humans.IMPORTANCE Herpetic lesions are a significant problem, and they are difficult to control with therapeutics. Our studies show that the severity of herpetic lesions in a mouse model can be diminished by changing the diet to include increased levels of SCFA, which act to inhibit the involvement of inflammatory T cells. We suggest that changing the diet to include higher levels of SCFA might be a useful approach to reducing the impact of recurrent herpetic lesions in humans.

Sodium Propionate Attenuates the Lipopolysaccharide-Induced Epithelial-Mesenchymal Transition via the PI3K/Akt/mTOR Signaling Pathway

Short-chain fatty acids (SCFAs), especially propionate, originate from the fermentation of dietary fiber in the gut and play a key role in inhibiting pulmonary inflammation. Chronic inflammation may induce an epithelial-mesenchymal transition (EMT) in alveolar epithelial cells and result in fibrotic disorders. This study was designed to investigate the beneficial effect of sodium propionate (SP) on lipopolysaccharide (LPS)-induced EMT. In cultured BEAS-2B cells, the protein expression levels of E-cadherin, α-smooth muscle actin (SMA), and vimentin were 0.66 ± 0.20, 1.44 ± 0.23, and 1.32 ± 0.21 in the LPS group vs 1.11 ± 0.36 (P < 0.05), 1.04 ± 0.30 (P < 0.05), and 0.96 ± 0.13 (P < 0.01) in the LPS + SP group (mean ± standard deviation), respectively. Meanwhile, LPS-triggered inflammatory cytokines and extracellular proteins were also reduced by SP administration in BEAS-2B cells. Moreover, SP treatment attenuated inflammation, EMT, extracellular matrix (ECM) deposition, and even fibrosis in a mouse EMT model. In terms of mechanism, LPS-treated BEAS-2B cells exhibited a higher level of phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) phosphorylation, which was interrupted by SP treatment. It is worth noting that the blockade of the PI3K/Akt/mTOR signaling cascade reduced the LPS-evoked EMT process in BEAS-2B cells. These results suggest that SP can block LPS-induced EMT via inhibition of the PI3K/Akt/mTOR signaling cascade, which provides a basis for possible clinical use of SP in airway and lung diseases.

Propionate alleviates high-fat diet-induced lipid dysmetabolism by modulating gut microbiota in mice

AIMS

The aims were to examine whether oral sodium propionate supplementation regulate lipid metabolism through modulating gut microbiota.

METHODS AND RESULTS

ICR male mice (26·98 ± 0·30 g) were randomly assigned to three groups (n = 10) and fed control diet (Con), high-fat diet (HFD) and HFD plus propionate (Pro) respectively. In this study, we found that HFD increased the weight of final body, inguinal white adipose tissues (iWAT), epididymal white adipose tissue (eWAT) and perirenal white adipose tissue (pWAT), as well as the adipocyte mean area of iWAT and eWAT in mice (P < 0·05), whereas sodium propionate treatment reduced the weight of iWAT and pWAT as well as adipocyte mean area of iWAT in mice fed a HFD (P < 0·05). Moreover, in the iWAT, the mRNA expression of lipogenesis genes, including peroxisome proliferator activated receptor γ, acetyl-CoA carboxylase and carnitine palmitoyl transferase-1β, was upregulated by HFD challenge (P < 0·05), and the elevation of these genes was nearly reversed to the level of control diet-fed mice by sodium propionate treatment. Meanwhile, sodium propionate treatment increased the hormone-sensitive lipase mRNA expression in the iWAT of HFD-fed mice (P < 0·05). High-throughput pyrosequencing of the 16S rRNA demonstrated that sodium propionate treatment significantly recovered the gut microbiota dysbiosis in HFD-fed mice, including the richness and diversity of microbiota and the ratio of Firmicutes to Bacteroidetes. Furthermore, the HFD-induced reductions in colonic levels of butyrate and valerate were reversed by sodium propionate treatment, which also normalized the serum LPS level seen in HFD-fed mice to the levels of the control diet-fed mice.

CONCLUSIONS

Collectively, these results indicated that sodium propionate treatment could improve lipid metabolism in HFD-fed mice, and the potential mechanisms might be via regulating gut microbiota.

SIGNIFICANCE AND IMPACT OF THE STUDY

We demonstrated for the first time that oral sodium propionate significantly improved HFD-induced dysbiosis of gut microbiota, indicating that the mitigative effect of propionate for HFD-induced lipid dysmetabolism might be mediated by gut microbiota in mice.

Propionate Protects against Lipopolysaccharide-Induced Mastitis in Mice by Restoring Blood-Milk Barrier Disruption and Suppressing Inflammatory Response

Mastitis, an inflammation of the mammary glands, is a major disease affecting dairy animal worldwide. Propionate is one of the main short-chain fatty acid that can exert multiple effects on the inflammatory process. The purpose of this study is to investigate the mechanisms underlying the protective effects of sodium propionate against lipopolysaccharide (LPS)-induced mastitis model in mice. The data mainly confirm that inflammation and blood–milk barrier breakdown contribute to progression of the disease in this model. In mice with LPS, sodium propionate attenuates the LPS-induced histopathological changes, inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) production, myeloperoxidase activity in mammary tissues. Given their importance in the blood–milk barrier, tight junction proteins occludin and claudin-3 are further investigated. Our results show that sodium propionate strikingly increases the expressions of occludin and claudin-3 and reduces the blood–milk barrier permeability in this model. Furthermore, in LPS-stimulated mouse mammary epithelial cells (mMECs), LPS increased the expressions of phosphorylated (p)-p65, p-IκB proteins, which is attenuated by sodium propionate. Finally, we examine the possibility that propionate acts as a histone deacetylase (HDAC) inhibitor, the results show that both sodium propionate and trichostatin A increase the level of histone H3 acetylation and inhibit the increased production of TNF-α, IL-6, and IL-1β in LPS-stimulated mMECs. These data suggest that sodium propionate protects against LPS-induced mastitis mainly by restoring blood–milk barrier disruption and suppressing inflammation via NF-κB signaling pathway and HDAC inhibition.