Sodium Butyrate Inhibits the Inflammation of Lipopolysaccharide-Induced Acute Lung Injury in Mice by Regulating the Toll-Like Receptor 4/Nuclear Factor κB Signaling Pathway

The Synthetic LXR Agonist GW3965 Attenuates Phosgene-Induced Acute Lung Injury Through the Modulation of PI3K/Akt and NF-κB Signalling Pathways

Phosgene, used in large-scale industrial production, is highly toxic and irritant. Accidental exposure can lead to varying degrees of injuries, with severe cases potentially resulting in acute lung injury or acute respiratory distress syndrome, resulting in a mortality rate of 40%-50%. The indirect damages of phosgene (inflammation and oxidative stress) are considered important factors in phosgene-induced acute lung injury (P-ALI). The expression of Liver X Receptor α (LXRα) significantly reduces during periods of inflammation. LXRs were initially discovered to be highly expressed in the liver, whereas LXRs are expressed in immune cells and vascular endothelial cells, playing a significant role in anti-inflammatory and antioxidant responses. LXRα may have pulmonary protection in P-ALI. However, evidence to verify this association is still lacking. In this study, rats were divided into six groups to explore the potential role of LXRα in P-ALI. This study found that GW3965 effectively activated LXRα, upregulated its expression and downregulated the levels of proinflammatory cytokines, inhibited malondialdehyde activity while enhancing superoxide dismutase activity, suppressed apoptosis and ameliorated the pathological processes of P-ALI, ultimately exerting pulmonary protection in P-ALI. Further validation revealed that the pulmonary protective effect of LXRα may be associated with the PI3K/Akt and NF-kB signalling pathways.

Altered gut microbiota and metabolite profiles in community-acquired pneumonia: a metagenomic and metabolomic study

Emerging evidence suggests that altered gut microbiota is linked to community-acquired pneumonia (CAP), but the potential mechanisms by which gut microbiota and its metabolites contribute to the development of CAP remain unclear. Fecal samples from 32 CAP patients and 36 healthy controls were analyzed through metagenomic sequencing and metabolomic profiling. The gut microbiota composition in CAP patients showed significant differences and lower diversity compared to healthy controls. Genera involved in short-chain fatty acid (SCFA) production, such as Faecalibacterium, Ruminococcus, and Eubacterium, as well as species like Faecalibacterium prausnitzii, Bifidobacterium adolescentis, Eubacterium rectale, Prevotella copri, and Ruminococcus bromii, were significantly depleted in CAP patients. Bacterial co-occurrence network analysis revealed an over-representation of pro-inflammatory bacteria, which contributed to the core gut microbiome in CAP patients. Metabolomic analysis of fecal samples identified a distinct metabolic profile, with a notable increase in arachidonic acid, but a decrease in secondary bile acids, such as deoxycholic acid, lithocholic acid, and ursodeoxycholic acid, compared to healthy controls. Spearman correlation analysis between differential microbiota and bile acids showed that Faecalibacterium prausnitzii, Bifidobacterium adolescentis, Eubacterium rectale, and Prevotella copri were positively correlated with ursocholic acid, lithocholic acid, and ursodeoxycholic acid, respectively. Our results suggest that the reduction in secondary bile acids, insufficient production of SCFAs, and an overabundance of pro-inflammatory bacteria may contribute to metabolic inflammation in the body. These factors could play a key role in the pathogenesis of CAP, driven by gut microbiota alterations.

IMPORTANCE

This study presents a comprehensive metagenomic and metabolomic analysis of fecal samples from community-acquired pneumonia (CAP) patients, identifying key characteristics, such as decreased secondary bile acids, imbalanced short-chain fatty acid production, and increased pro-inflammatory bacteria. These findings provide valuable insights into the mechanisms linking gut microbiota alterations to CAP pathogenesis and suggest that targeting the gut microbiota could be a promising strategy for intervening in CAP.

Effects of Short Chain Fatty Acid-Butyrate Supplementation on the Disease Severity, Inflammation, and Psychological Factors in Patients With Active Ulcerative Colitis: A Double-Blind Randomized Controlled Trial

Background: Depression and anxiety are common in UC patients due to gut microbiota dysbiosis and increased proinflammatory markers. Butyrate, a short-chain fatty acid, participates in the regulation of gut microbiota and inflammation and has neuroprotective effects in neurodegenerative disease. Therefore, we assessed the effects of sodium butyrate supplementation on the disease severity, inflammation, and psychological factors in active UC patients. Methods: This study was a randomized, parallel, double-blind controlled trial. Participants in the intervention (n = 18) and control (n = 18) groups received 600 mg/kg of sodium butyrate or rice starch as a placebo with their main meal, respectively, for 12 weeks. The partial Mayo score was used to evaluate disease severity, while the Westergren method was employed to assess the erythrocyte sedimentation rate (ESR). NLR and PLR were determined using an automated analyzer (XS-500i, Sysmex). Moreover, the psychological factors were assessed by the hospital anxiety depression scale (HADS) and the general health questionnaire (GHQ). Results: In comparison with placebo, sodium-butyrate supplementation significantly decreased the ESR level (-6.66 ± 1.56 vs. 3.00 ± 2.11, p=0.01), NLR (-0.24 ± 0.1 vs. 0.33 ± 0.23, p=0.02), Mayo score (-2.33 ± 0.41 vs. 0.22 ± 0.40, p < 0.001), HADS anxiety score (-2.77 ± 0.64 vs. 0.94 ± 0.63, p=0.001), HADS depression score (-2.38 ± 0.47 vs. 0.61 ± 0.33, p < 0.001), and GHQ total score (-12.11 ± 1.48 vs. 3.55 ± 1.39, p < 0.001). Conclusion: Butyrate could serve as an effective adjuvant treatment for reducing disease severity and alleviating psychological symptoms. This trial was registered on the Research Ethics Committee of Shiraz University of Medical Sciences, with the reference number IR.SUMS.SCHEANUT.REC.1400.037. Trial Registration: Iranian Registry of Clinical Trials: IRCT20211214053401N1.

Therapeutic potential of short-chain fatty acids for acute lung injury: a systematic review and meta-analysis of preclinical animal studies

Background

Short-chain fatty acids (SCFAs), derived from the fermentation of dietary fiber by intestinal commensal bacteria, have demonstrated protective effects against acute lung injury (ALI) in animal models. However, the findings have shown variability across different studies. It is necessary to conduct a comprehensive evaluation of the efficacy of these treatments and their consistency.

Objective

This systematic review and meta-analysis aimed to explore the effects of SCFAs on ALI based on preclinical research evidence, in order to provide new treatment strategies for ALI.

Methods

We included studies that tested the effects of SCFAs on ALI in animal models. This study was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search for relevant studies was conducted in the PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases up to February 2024. The data were extracted in accordance with the established selection criteria, and the risk of bias was evaluated for each study.

Results

A total of 16 articles were finally included in the meta-analysis. The results indicated that the SCFAs significantly reduced lung wet-to-dry weight (SMD = -2.75, 95% CI = -3.46 to -2.03, p < 0.00001), lung injury scores (SMD = -5.07, 95% CI = -6.25 to -3.89, p < 0.00001), myeloperoxidase (SMD = -3.37, 95% CI = -4.05 to -2.70, p < 0.00001), tumor necrosis factor-alpha (SMD = -3.31, 95% CI = -4.45 to -2.16, p < 0.00001) and malondialdehyde (SMD = -3.91, 95% CI = -5.37 to -2.44, p < 0.00001) levels in animal models of ALI. The results of the subgroup analysis indicated that the efficacy of SCFAs varies significantly with dosage and duration of treatment.

Conclusion

SCFAs can reduce inflammation and oxidative stress in animal models of ALI. The clinical efficacy of SCFAs for ALI deserves further in-depth research.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=584008, CRD42024584008.

Gut feelings on short-chain fatty acids to regulate respiratory health

Respiratory infections and diseases pose significant challenges to society and healthcare systems, underscoring the need for preventative and therapeutic strategies. Recent research in rodent models indicates that short-chain fatty acids (SCFAs), metabolites produced by gut bacteria, may offer medicinal benefits for respiratory conditions. In this opinion, we summarize the current literature that highlights the potential of SCFAs to enhance immune balance in humans. SCFAs have demonstrated the potential to decrease the risk of primary and secondary respiratory infections, modulate allergic airway exacerbations, and improve overall epithelial pathogen defenses. Therefore, we suggest that systemic SCFA levels could be targeted to support gut and respiratory health in specific groups, such as patients in hospital, women and their offspring, children, older adults, and athletes/military personnel.

Sodium propionate ameliorates lipopolysaccharide-induced acute respiratory distress syndrome in rats via the PI3K/AKT/mTOR signaling pathway

Acute respiratory distress syndrome (ARDS) is a severe lung disease characterized by significant hypoxemia, which impairs the oxygen supply necessary for optimal lung function. This study aimed to investigate the effects of sodium propionate (SP), the primary end product of intestinal flora fermentation of dietary fiber, on lipopolysaccharide (LPS)-induced ARDS in rats. The rats were treated with SP, after which the lung wet/dry ratio, arterial partial oxygen pressure (PaO2), levels of pro- and anti-inflammatory cytokines, tight junction proteins ZO-1 and Occludin, as well as LC3 and phosphorylated PI3K (p-PI3K)/p-AKT/p-mTOR protein levels, were measured. Additionally, histopathological analysis was conducted. The results indicated that SP effectively alleviated arterial hypoxemia in rats and mitigated the pathological damage to both intestinal and lung tissues caused by LPS. Notably, SP significantly reduced the levels of inflammatory factors TNF-α and IL-6 in the blood and bronchoalveolar lavage fluid (BALF) of ARDS rats, while increasing the concentration of the anti-inflammatory factor IL-10. Furthermore, SP inhibited the activation of the PI3K/AKT/mTOR signaling pathway and enhanced the LC3II/LC3I ratio in lung tissue. Therefore, SP may improve LPS-induced ARDS in rats by inhibiting the activation of the PI3K/AKT/mTOR signaling pathway, promoting autophagy, decreasing the production and release of inflammatory markers, and reducing alveolar epithelial damage.

Associations between blood nickel and lung function in young Chinese: An observational study combining epidemiology and metabolomics

Prior research has explored the relationship between occupational exposure to nickel and lung function. Nonetheless, there is limited research examining the correlation between blood nickel levels and lung function among young adults in the general population. The metabolomic changes associated with nickel exposure have not been well elucidated. On August 23, 2019, we enrolled 257 undergraduate participants from the Chinese Undergraduates Cohort to undergo measurements of blood nickel levels and lung function. The follow-up study was conducted in May 2021. A linear mixed-effects model was employed to assess the relationship between blood nickel levels and lung function. We also conducted stratified analyses by home address. In addition, in order to explore the biological mechanism of lung function damage caused by nickel exposure, we performed metabolomic analyses of baseline serum samples (N = 251). Both analysis of variance and mixed linear effect models were utilized to assess the impact of blood nickel exposure on metabolism. Our findings from cross-sectional and cohort analyses revealed a significant association between blood nickel levels and decreased forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) among young adults in the general population. Furthermore, we found stronger associations in urban areas. In metabolomics analysis, a total of nine metabolites were significantly changed under blood nickel exposure. The changed metabolites were mainly enriched in six pathways including carbohydrate, amino acid, and cofactor vitamin metabolism. These metabolic pathways involve inflammation and oxidative stress, indicating that high concentrations of nickel exposure can cause inflammation and oxidative stress by disrupting the above metabolism of the body.

Structural characterization and therapeutic effect of Alhagi honey oligosaccharide on liver fibrosis in mice

Alhagi honey is derived from the secretory granules of Alhagi pseudoalhagi Desv., a leguminous plant commonly known as camelthorn. Modern medical research has demonstrated that the extract of Alhagi honey possesses regulatory properties for the gastrointestinal tract and immune system, as well as exerts anti-tumor, anti-oxidative, anti-inflammatory, anti-bacterial, and hepatoprotective effects. The aim of this study was to isolate and purify oligosaccharide monomers (referred to as Mel) from camelthorn and elucidate their structural characteristics. Subsequently, the impact of Mel on liver injury induced by carbon tetrachloride (CCl4) in mice was investigated. The analysis identified the isolated oligosaccharide monomer (α-D-Glcp-(1 → 3)-β-D-Fruf-(2 → 1)-α-D-Glcp), with the molecular formula C18H32O16. In a mouse model of CCl4-induced liver fibrosis, Mel demonstrated significant therapeutic effects by attenuating the development of fibrosis. Moreover, it enhanced anti-oxidant enzyme activity (glutathione peroxidase and superoxide dismutase) in liver tissues, thereby reducing oxidative stress markers (malondialdehyde and reactive oxygen species). Mel also improved serum albumin levels, lowered liver enzyme activities (aspartate aminotransferase and alanine aminotransferase), and decreased inflammatory factors (tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6). Immunohistochemistry, immunofluorescence, and western blotting analyses confirmed the ability of Mel to downregulate hepatic stellate cell-specific markers (collagen type I alpha 1 chain, alpha-smooth muscle actin, transforming growth factor-beta 1. Non-targeted metabolomics analysis revealed the influence of Mel on metabolic pathways related to glutathione, niacin, pyrimidine, butyric acid, and amino acids. In conclusion, the results of our study highlight the promising potential of Mel, derived from Alhagi honey, as a viable candidate drug for treating liver fibrosis. This discovery offers a potentially advantageous option for individuals seeking natural and effective means to promote liver health.

Donor Inhalation of Nebulized Dexmedetomidine Alleviates Ischemia-Reperfusion Injury in Rat Lung Transplantation

INTRODUCTION

The occurrence of lung ischemia-reperfusion injury (LIRI) after lung transplantation results in primary graft dysfunction (PGD) in more than 50% of cases, which seriously affects the prognosis of recipients. Currently, donor lung protection is the focus of research on improving graft survival in lung transplant recipients. Dexmedetomidine (Dex) is a widely used general anesthesia adjuvant in clinical practice to alleviate ischemia-reperfusion injury in the lungs, liver, heart, kidneys, and brain. However, intravenous infusion of Dex can cause negative effects on the cardiovascular system. Inhaling nebulized Dex can directly act on the alveolar tissue and alleviate its cardiovascular inhibitory effect by reducing drug intake. This study aimed to investigate the effect of donor nebulized Dex inhalation on LIRI after lung transplantation in rats.

METHODS

We randomly divided the male Sprague-Dawley rats into donor rats and recipient rats, and allowed the donor rats to inhale nebulized Dex or physiological saline 15 min before surgery. The donor lung was refrigerated for 8 h before each single-lung transplant. After 2 h of reperfusion of the transplanted lung, serum and transplanted lung tissue were collected. The wet-to-dry weight ratio of the lung tissue was measured, arterial blood gas was detected, and histopathology changes, oxidative stress, inflammatory reactions, and apoptosis were evaluated.

RESULTS

Pretransplant inhalation of Dex through the donor's lung reduced the injury of the transplanted lung, increased the levels of malondialdehyde and myeloperoxidase, and decreased the levels of superoxide dismutase and glutathione in the lung tissue. Moreover, nebulized Dex inhalation of the donor lung inhibited LIRI-induced tumor necrosis factor-α, interleukin-6, and inducible nitric oxide synthase expression and also suppressed nuclear factor kappa B phosphorylation. Nebulized Dex inhalation reduced the rate of cell apoptosis in the transplanted lung tissue by inhibiting the upregulation of Bax, downregulation of Bcl-2, and increase in caspase-3 lysis caused by LIRI.

CONCLUSION

Inhalation of atomized Dex is a potential donor lung protection strategy, which can be used to reduce LIRI after lung transplantation and may be helpful to improve the occurrence of PGD and prognosis of lung transplant recipients.

Research Progress on the Correlation Between Hypertension and Gut Microbiota

Among cardiovascular diseases, hypertension is the most important risk factor for morbidity and mortality worldwide, and its pathogenesis is complex, involving genetic, dietary and environmental factors. The characteristics of the gut microbiota can vary in response to increased blood pressure (BP) and influence the development and progression of hypertension. This paper describes five aspects of the relationship between hypertension and the gut microbiota, namely, the different types of gut microbiota, metabolites of the gut microbiota, sympathetic activation, gut-brain interactions, the effects of exercise and dietary patterns and the treatment of the gut microbiota through probiotics, faecal microbiota transplantation (FMT) and herbal remedies, providing new clues for the future prevention of hypertension. Diet, exercise and traditional Chinese medicine may contribute to long-term improvements in hypertension, although the effects of probiotics and FMT still need to be validated in large populations.

Involvement of GPR43 Receptor in Effect of Lacticaseibacillus rhamnosus on Murine Steroid Resistant Chronic Obstructive Pulmonary Disease: Relevance to Pro-Inflammatory Mediators and Oxidative Stress in Human Macrophages

BACKGROUND

Cytokine storm and oxidative stress are present in chronic obstructive pulmonary disease (COPD). Individuals with COPD present high levels of NF-κB-associated cytokines and pro-oxidant agents as well as low levels of Nrf2-associated antioxidants. This condition creates a steroid-resistant inflammatory microenvironment. Lacticaseibacillus rhamnosus (Lr) is a known anti-cytokine in lung diseases; however, the effect of Lr on lung inflammation and oxidative stress in steroid-resistant COPD mice remains unknown.

OBJECTIVE

Thus, we investigated the Lr effect on lung inflammation and oxidative stress in mice and macrophages exposed to cigarette smoke extract (CSE) and unresponsive to steroids.

METHODS

Mice and macrophages received dexamethasone or GLPG-094 (a GPR43 inhibitor), and only the macrophages received butyrate (but), all treatments being given before CSE. Lung inflammation was evaluated from the leukocyte population, airway remodeling, cytokines, and NF-κB. Oxidative stress disturbance was measured from ROS, 8-isoprostane, NADPH oxidase, TBARS, SOD, catalase, HO-1, and Nrf2.

RESULTS

Lr attenuated cellularity, mucus, collagen, cytokines, ROS, 8-isoprostane, NADPH oxidase, and TBARS. Otherwise, SOD, catalase, HO-1, and Nrf2 were upregulated in Lr-treated COPD mice. Anti-cytokine and antioxidant effects of butyrate also occurred in CSE-exposed macrophages. GLPG-094 rendered Lr and butyrate less effective.

CONCLUSIONS

Lr attenuates lung inflammation and oxidative stress in COPD mice, suggesting the presence of a GPR43 receptor-dependent mechanism also found in macrophages.

Preventive Effect of the Total Polyphenols from Nymphaea candida on Sepsis-Induced Acute Lung Injury in Mice via Gut Microbiota and NLRP3, TLR-4/NF-κB Pathway

This study aimed to investigate the preventive effects of the total polyphenols from Nymphaea candida (NCTP) on LPS-induced septic acute lung injury (ALI) in mice and its mechanisms. NCTP could significantly ameliorate LPS-induced lung tissue pathological injury in mice as well as lung wet/dry ratio and MPO activities (p < 0.05). NCTP could significantly decrease the blood leukocyte, neutrophil, monocyte, basophil, and eosinophil amounts and LPS contents in ALI mice compared with the model group (p < 0.05), improving lymphocyte amounts (p < 0.05). Moreover, compared with the model group, NCTP could decrease lung tissue TNF-α, IL-6, and IL-1β levels (p < 0.05) and downregulate the protein expression of TLR4, MyD88, TRAF6, IKKβ, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, NLRP3, ASC, and Caspase1 in lung tissues (p < 0.05). Furthermore, NCTP could inhibit ileum histopathological injuries, restoring the ileum tight junctions by increasing the expression of ZO-1 and occludin. Simultaneously, NCTP could reverse the gut microbiota disorder, restore the diversity of gut microbiota, increase the relative abundance of Clostridiales and Lachnospiraceae, and enhance the content of SCFAs (acetic acid, propionic acid, and butyric acid) in feces. These results suggested that NCTP has preventive effects on septic ALI, and its mechanism is related to the regulation of gut microbiota, SCFA metabolism, and the TLR-4/NF-κB and NLRP3 pathways.

Orally Administered Lactobacillus rhamnosus CY12 Alleviates DSS-Induced Colitis in Mice by Restoring the Intestinal Barrier and Inhibiting the TLR4-MyD88-NF-κB Pathway via Intestinal Microbiota Modulation

Oral ingestion of probiotics is a promising approach to relieving inflammatory disease through regulating the gut microbiota. A newly discovered strain, Lactobacillus rhamnosus CY12 (LCY12), obtained from cattle-yak milk, displayed numerous probiotic properties. These included enhanced viability in low pH and bile environments, adhesion capabilities, and potent antimicrobial effects. The research aimed to explore the beneficial impacts of the novel LCY12 strain on colitis in mice induced by dextran sulfate sodium (DSS) and to elucidate the underlying molecular mechanisms. The results of the study showed that administration of LCY12 effectively helped to reduce the negative effects of DSS-induced body weight loss, disease activity index score, colon length shortening, loss of goblet cells, and overall histopathological scores in the intestines. Simultaneously, LCY12 administration significantly alleviated intestinal inflammation and safeguarded intestinal barrier integrity by enhancing IL-10 levels, while dampening IL-6, IL-1β, and TNF-α production. Additionally, LCY12 boosted the presence of tight junction proteins. Furthermore, LCY12 hindered the TLR4/MyD88/NF-κB signaling pathway by downregulating TLR4 and MyD88 expression, inactivating phosphorylated IκBα, and preventing translocation of NF-κB p65 from the cytoplasm to the nucleus. The LCY12 also increased specific intestinal microbial communities and short-chain fatty acid (SCFA) production. Altogether, LCY12 oral administration alleviated colitis induced with DSS in mice by improving intestinal barrier function and regulating inflammatory cytokines, SCFA production, and intestinal microbiota.

Short-Chain Fatty Acid (SCFA) as a Connecting Link between Microbiota and Gut-Lung Axis-A Potential Therapeutic Intervention to Improve Lung Health

The microbiome is an integral part of the human gut, and it plays a crucial role in the development of the immune system and homeostasis. Apart from the gut microbiome, the airway microbial community also forms a distinct and crucial part of the human microbiota. Furthermore, several studies indicate the existence of communication between the gut microbiome and their metabolites with the lung airways, called "gut-lung axis". Perturbations in gut microbiota composition, termed dysbiosis, can have acute and chronic effects on the pathophysiology of lung diseases. Microbes and their metabolites in lung stimulate various innate immune pathways, which modulate the expression of the inflammatory genes in pulmonary leukocytes. For instance, gut microbiota-derived metabolites such as short-chain fatty acids can suppress lung inflammation through the activation of G protein-coupled receptors (free fatty acid receptors) and can also inhibit histone deacetylase, which in turn influences the severity of acute and chronic respiratory diseases. Thus, modulation of the gut microbiome composition through probiotic/prebiotic usage and fecal microbiota transplantation can lead to alterations in lung homeostasis and immunity. The resulting manipulation of immune cells function through microbiota and their key metabolites paves the way for the development of novel therapeutic strategies in improving the lung health of individuals affected with various lung diseases including SARS-CoV-2. This review will shed light upon the mechanistic aspect of immune system programming through gut and lung microbiota and exploration of the relationship between gut-lung microbiome and also highlight the therapeutic potential of gut microbiota-derived metabolites in the management of respiratory diseases.

Tempol alleviates acute lung injury by affecting glutathione synthesis through Nrf2 and inhibiting ferroptosis in lung epithelial cells

As a life-threatening disease, acute lung injury (ALI) may progress to chronic pulmonary fibrosis. For the treatment of lung injury, Tempol is a superoxide dismutase mimetic and intracellular redox agent that can be a potential drug. This study investigated the regulatory mechanism of Tempol in the treatment of ALI. A mouse model of ALI was established, and HE staining was used to examine histomorphology. The CCK-8 assay was used to measure cell viability, and oxidative stress was assessed by corresponding kits. Flow cytometry and dichlorodihydrofluorescein diacetate staining assays were used to detect reactive oxygen species (ROS) levels. Protein expression levels were measured by Western blot analysis and ELISA. Pulmonary vascular permeability was used to measure the lung wet/dry weight ratio. The level of oxidative stress was increased in ALI mice, and the level of ferroptosis was upregulated. Tempol inhibited this effect and alleviated ALI. The administration of Tempol alleviated the pathological changes in ALI, inhibited pulmonary vascular permeability, and improved lung injury in ALI mice. The upregulation of genes essential for glutathione (GSH) metabolism induced by lipopolysaccharide (LPS) was inhibited by Tempol. In addition, nuclear factor-related factor 2 (Nrf2) is activated by Tempol therapy to regulate the de novo synthesis pathway of GSH, thereby alleviating LPS-induced lung epithelial cell damage. The results showed that Tempol alleviated ALI by activating the Nrf2 pathway to inhibit oxidative stress and ferroptosis in lung epithelial cells. In conclusion, this study demonstrates that Tempol alleviates ALI by inhibiting ferroptosis in lung epithelial cells through the effect of Nrf2 on GSH synthesis.

Gut Microbiome-Based Therapeutics in Critically Ill Adult Patients-A Narrative Review

The gut microbiota plays a crucial role in the human microenvironment. Dysbiosis of the gut microbiota is a common pathophysiological phenomenon in critically ill patients. Therefore, utilizing intestinal microbiota to prevent complications and improve the prognosis of critically ill patients is a possible therapeutic direction. The gut microbiome-based therapeutics approach focuses on improving intestinal microbiota homeostasis by modulating its diversity, or treating critical illness by altering the metabolites of intestinal microbiota. There is growing evidence that fecal microbiota transplantation (FMT), selective digestive decontamination (SDD), and microbiota-derived therapies are all effective treatments for critical illness. However, different treatments are appropriate for different conditions, and more evidence is needed to support the selection of optimal gut microbiota-related treatments for different diseases. This narrative review summarizes the curative effects and limitations of microbiome-based therapeutics in different critically ill adult patients, aiming to provide possible directions for gut microbiome-based therapeutics for critically ill patients such as ventilator-associated pneumonia, sepsis, acute respiratory distress syndrome, and COVID-19, etc.

Sodium butyrate (SB) ameliorated inflammation of COPD induced by cigarette smoke through activating the GPR43 to inhibit NF-κB/MAPKs signaling pathways

Cigarette smoke is recognized as a major trigger for individuals with chronic obstructive pulmonary disease (COPD), leading to an amplified inflammatory response. The onset and progression of COPD are affected by multiple environmental and genetic risk factors, such as inflammatory mechanisms, oxidative stress, and an imbalance between proteinase and antiprotease. As a result, conventional drug therapies often have limited effectiveness. This study aimed to investigate the anti-inflammatory effect of sodium butyrate (SB) in COPD and explore its molecular mechanism, thereby deepening our understanding of the potential application of SB in the treatment of COPD. In our study, we observed an increase in the mRNA and protein expressions of inflammatory factors interleukin-1beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), Matrix metallopeptidase 9 (MMP9) and MMP12 in both NR8383 cell and rat models of COPD. However, these expressions were significantly reduced after SB treatment. Meanwhile, SB treatment effectively decreased the phosphorylation levels of nuclear transcription factor-kappa B (NF-κB) p65, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) and inhibited the nuclear translocation of these proteins in the COPD cells, leading to a reduction in the expression of various inflammatory cytokines. Additionally, SB also inhibited the expression level of the Nod-like receptor pyrin domain 3 (NLRP3) inflammasome, which consists of NLRP3, apoptosis-associated speck-like protein (ASC), and Caspase-1 in the cigeratte smoke extract (CSE)-stimulated cells. Our results showed that CSE down-regulated the mRNA levels of G-protein-coupled receptor 43 (GPR43) and GPR109A, while SB only up-regulated the expression of GPR43 and had no effect on GPR109A. Moreover, additional analysis demonstrated that the knockdown of GPR43 diminishes the anti-inflammatory effects of SB. It is evident that siRNA-mediated knockdown of GPR43 prevented the reduction in mRNA expression of IL-1β, IL-6, TNF-α, MMP9, and MMP12, as well as the expression of phosphorylated proteins NF-κB p65, JNK, and p38 MAPKs with SB treatment. These findings revealed a SB/GPR43 mediated pathway essential for attenuating pulmonary inflammatory responses in COPD, which may offer potential new treatments for COPD.

Butyrate protects against MRSA pneumonia via regulating gut-lung microbiota and alveolar macrophage M2 polarization

IMPORTANCE

Pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) continues to carry a high burden in terms of mortality. With the roles of gut microbiota in mediating lung diseases being gradually uncovered, the details of the molecular mechanism of the "gut-lung axis" mediated by beneficial microorganisms and small-molecule metabolites have gradually attracted the attention of researchers. However, further studies are still necessary to determine the efficacy of microbial-based interventions. Our findings indicate that sodium butyrate (NaB) alleviates MRSA-induced pulmonary inflammation by improving gut-lung microbiota and promoting M2 polarization of alveolar macrophages. Therefore, the preventive administration of NaB might be explored as an effective strategy to control MRSA pneumonia.

A high-concentrate diet induces mitochondrial dysfunction by activating the MAPK signaling pathway in the mammary gland of dairy cows

Subacute rumen acidosis can lead to mastitis in dairy cows. Mitochondrial dysfunction is closely related to the inflammatory response. This experiment was conducted to investigate the effects of a high-concentrate diet on mammary gland inflammation and mitochondrial damage in dairy cows. Twelve Holstein dairy cows in mid-lactation were randomly divided into 2 groups and fed a 40% concentrate (low concentrate, LC) diet or a 60% concentrate (high concentrate, HC) diet. Cows were fed individually, and the experiment lasted for 3 wk. After the experiment, mammary gland tissue, blood, and rumen fluid were collected. Compared with the LC diet, the HC diet significantly decreased rumen pH; the pH was <5.6 for more than 3 h. The HC diet also increased the concentration of LPS in the blood (7.17 ± 1.25 µg/mL vs. 12.12 ± 1.26 µg/mL), which indicated that feeding the HC diet successfully induced subacute rumen acidosis. The HC diet also increased the concentration of Ca2+ (34.80 ± 4.23 µg/g vs. 46.87 ± 7.24 µg/g) in the mammary gland and upregulated the expression of inflammatory factors IL-6 (1,128.31 ± 147.53 pg/g vs. 1,538.42 ± 241.38 pg/g), IL-1β (69.67 ± 5.86 pg/g vs. 90.13 ± 4.78 pg/g), and tumor necrosis factor-α (91.99 ± 10.43 pg/g vs. 131.75 ± 17.89 pg/g) in mammary venous blood. The HC diet also increased the activity of myeloperoxidase (0.41 ± 0.05 U/g vs. 0.71 ± 0.11 U/g) and decreased the content of ATP (0.47 ± 0.10 µg/mL vs. 0.32 ± 0.11 µg/mL) in the mammary gland. In addition, phosphorylation of JNK (1.00 ± 0.21 vs. 2.84 ± 0.75), ERK (1.00 ± 0.20 vs. 1.53 ± 0.31), and p38 (1.00 ± 0.13 vs. 1.47 ± 0.41) and protein expression of IL-6 (1.00 ± 0.22 vs. 2.21 ± 0.27) and IL-8 (1.00 ± 0.17 vs. 1.96 ± 0.26) were enhanced in cows of the HC group, indicating that the mitogen-activated protein kinase (MAPK) signaling pathway was activated. Compared with the LC diet, the HC diet reduced the protein expression of mitochondrial biogenesis-related proteins PGC-1α (1.00 ± 0.17 vs. 0.55 ± 0.12), NRF1 (1.00 ± 0.17 vs. 0.60 ± 0.10), TFAM (1.00 ± 0.10 vs. 0.73 ± 0.09), and SIRTI (1.00 ± 0.44 vs. 0.40 ± 0.10). The HC diet promoted mitochondrial fission and inhibited mitochondrial fusion by reducing protein expression of MFN1 (1.00 ± 0.31 vs. 0.49 ± 0.09), MFN2 (1.00 ± 0.19 vs. 0.69 ± 0.13), and OPA1 (1.00 ± 0.08 vs. 0.72 ± 0.07), and by increasing that of DRP1 (1.00 ± 0.09 vs. 1.39 ± 0.10), MFF (1.00 ± 0.15 vs. 1.89 ± 0.12), and TTC1/FIS1 (1.00 ± 0.08 vs. 1.76 ± 0.14), leading to mitochondrial dysfunction. The HC diet increased mitochondrial permeability by upregulating the protein expression of VDAC1 (1.00 ± 0.42 vs. 1.90 ± 0.44), ANT (1.00 ± 0.22 vs. 1.27 ± 0.17), and CYPD (1.00 ± 0.41 vs. 1.82 ± 0.43). Taken together, these results indicated that feeding the HC diet induced mitochondrial damage via the MAPK signaling pathway in the mammary gland of dairy cows.

The Role of Short-Chain Fatty Acids in Acute Pancreatitis

Acute pancreatitis (AP) is a digestive emergency and can develop into a systematic illness. The role of the gut in the progression and deterioration of AP has drawn much attention from researchers, and areas of interest include dysbiosis of the intestinal flora, weakened intestinal barrier function, and bacterial and endotoxin translocation. Short-chain fatty acids (SCFAs), as one of the metabolites of gut microbiota, have been proven to be depleted in AP patients. SCFAs help restore gut homeostasis by rebuilding gut flora, stabilizing the intestinal epithelial barrier, and regulating inflammation. SCFAs can also suppress systematic inflammatory responses, improve the injured pancreas, and prevent and protect other organ dysfunctions. Based on multiple beneficial effects, increasing SCFAs is an essential idea of gut protective treatment in AP. Specific strategies include the direct use of butyrate or indirect supplementation through fiber, pre/pro/synbiotics, or fecal microbiota transplantation as a promising adjective therapy to enteral nutrition.

MNQ derivative D21 protects against LPS-induced inflammatory damage in bovine ovarian follicular GCs in vitro via the steroid biosynthesis signaling pathway

Bacterial infections of the reproductive system of dairy cows lead to inflammation, and lipopolysaccharide (LPS) of the cell wall of Gram-negative bacteria is the main pathogenic component of inflammation. LPS inhibits follicular growth and development and alters the expression of follicular granulosa cells (GCs) genes in the ovary, leading to their functional disorders. Naphthoquinones have anti-inflammatory effects. In this experiment, 2-methoxy-1,4-naphthoquinone (MNQ), an extract of Impatiens balsamina L, and its derivative D₂₁ were used to eliminate the inflammatory response of GCs exposed to LPS in vitro and to restore functional disorders in GCs. The anti-inflammatory effects of the two compounds were compared and their mechanism of action was investigated. The cytotoxicity of MNQ and its derivative D₂₁ on follicular GCs was determined by MTT method. The relative expression of inflammatory factors and steroid synthesis-related genes were determined by qRT-PCR. The protective effects of MNQ and D₂₁ on cellular inflammatory damage were observed by TEM. ELISA were performed to detect the levels of estradiol (E₂) and progesterone (P₄) in the culture supernatant. The expression of differential genes was analyzed by RNA-seq, and GO and KEGG enrichment analysis of differential genes were performed to investigate the mechanism of anti-inflammatory effect of D₂₁. The results showed that the maximum no-cytotoxic concentrations of MNQ and D₂₁ acting on GCs for 12 h were 4 μM and 64 μM, respectively. LPS concentration of 10 μg/mL had little effect on the survival of follicular GCs, but the relative expressions of IL-6, IL-1β and TNF-α were significantly higher (P < 0.05). The results of qRT-PCR, ELISA and TEM observations showed that the anti-inflammatory effect of D₂₁ was stronger than that of MNQ. RNA-seq analysis revealed a total of 341 differential genes between the LPS vs CK group (Control group) and the D₂₁+L vs LPS group, which were mainly enriched in signaling pathways such as steroid biosynthesis. Nine genes in this signaling pathway were analyzed, and the RNA-seq and qRT-PCR results were found to be basically consistent. In this study, we confirmed that derivative D₂₁ has stronger in vitro anti-inflammatory effects and better efficacy in protecting bovine follicular GCs from inflammatory damage than MNQ and acts through the steroid biosynthesis signaling pathway.

rFGF4 alleviates lipopolysaccharide-induced acute lung injury by inhibiting the TLR4/NF-κB signaling pathway

Acute lung injury (ALI) is a serious and common clinical disease. Despite significant progress in ALI treatment, the morbidity and mortality rates remain high. However, no effective drug has been discovered for ALI. FGF4, a member of the FGF family, plays an important role in the regulation of various physiological and pathological processes. Therefore, in the present study, we aimed to study the protective effects of FGF4 against LPS-induced lung injury in vivo and in vitro. We found that rFGF4 treatment improved the lung W/D weight ratio, the survival rate, immune cell infiltration and protein concentrations in mice with LPS-induced ALI. Histological analysis revealed that rFGF4 significantly attenuated lung tissue injury and cell apoptosis. Furthermore, rFGF4 inhibited the activation of the TLR4/NF-κB signaling pathway and the production of pro-inflammatory mediators in LPS-injured lung tissues, murine alveolar macrophages (MH-S) and murine pulmonary epithelial (MLE-12) cells. The results of cell experiments further verified that rFGF4 inhibited the production of inflammatory mediators in MH-S cells and MLE-12 cells by regulating the TLR4/NF-κB signaling pathway. These results revealed that rFGF4 protected lung tissues and inhibited inflammatory mediators in mice with LPS-induced ALI by inhibiting the TLR4/NF-κB signaling pathway in MH-S and MLE-12 cells.

Neuroprotective Effects of Sodium Butyrate by Restoring Gut Microbiota and Inhibiting TLR4 Signaling in Mice with MPTP-Induced Parkinson's Disease

Parkinson's disease (PD) is a prevalent type of neurodegenerative disease. There is mounting evidence that the gut microbiota is involved in the pathogenesis of PD. Sodium butyrate (NaB) can regulate gut microbiota and improve brain functioning in neurological disorders. Hence, we examined whether the neuroprotective function of NaB on PD was mediated by the modulation of gut microbial dysbiosis and revealed its possible mechanisms. Mice were administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days to construct the PD model. NaB gavage was given 2 h after the daily MPTP injections for 21 days. NaB improved the motor functioning of PD mice, increased striatal neurotransmitter levels, and reduced the death of dopaminergic neurons. The 16S rRNA sequencing analysis revealed that NaB restored the gut microbial dysbiosis. NaB also attenuated the intestinal barrier's disruption and reduced serum, colon, and striatal pro-inflammatory cytokines, along with inhibiting the overactivation of glial cells, suggesting an inhibitory effect on inflammation from NaB throughout the gut-brain axis of the PD mice. Mechanistic studies revealed that NaB treatment suppressed the TLR4/MyD88/NF-kB pathway in the colon and striatum. In summary, NaB had a neuroprotective impact on the PD mice, likely linked to its regulation of gut microbiota to inhibit gut-brain axis inflammation.

Butyrate producers, "The Sentinel of Gut": Their intestinal significance with and beyond butyrate, and prospective use as microbial therapeutics

Gut-microbial butyrate is a short-chain fatty acid (SCFA) of significant physiological importance than the other major SCFAs (acetate and propionate). Most butyrate producers belong to the Clostridium cluster of the phylum Firmicutes, such as Faecalibacterium, Roseburia, Eubacterium, Anaerostipes, Coprococcus, Subdoligranulum, and Anaerobutyricum. They metabolize carbohydrates via the butyryl-CoA: acetate CoA-transferase pathway and butyrate kinase terminal enzymes to produce most of butyrate. Although, in minor fractions, amino acids can also be utilized to generate butyrate via glutamate and lysine pathways. Butyrogenic microbes play a vital role in various gut-associated metabolisms. Butyrate is used by colonocytes to generate energy, stabilizes hypoxia-inducible factor to maintain the anaerobic environment in the gut, maintains gut barrier integrity by regulating Claudin-1 and synaptopodin expression, limits pro-inflammatory cytokines (IL-6, IL-12), and inhibits oncogenic pathways (Akt/ERK, Wnt, and TGF-β signaling). Colonic butyrate producers shape the gut microbial community by secreting various anti-microbial substances, such as cathelicidins, reuterin, and β-defensin-1, and maintain gut homeostasis by releasing anti-inflammatory molecules, such as IgA, vitamin B, and microbial anti-inflammatory molecules. Additionally, butyrate producers, such as Roseburia, produce anti-carcinogenic metabolites, such as shikimic acid and a precursor of conjugated linoleic acid. In this review, we summarized the significance of butyrate, critically examined the role and relevance of butyrate producers, and contextualized their importance as microbial therapeutics.

Sodium butyrate pretreatment mitigates lipopolysaccharide-induced inflammation through the TLR4/NF-κB signaling pathway in bovine embryo trachea cells

The present study investigated the anti-inflammatory effects and potential mechanisms of sodium butyrate (SB) in bovine embryo tracheal cells (EBTr) stimulated with lipopolysaccharide (LPS). EBTr were exposed to either 1 mmol/L SB for 18 h for the SB group (SB) or to 0.4 μg/mL LPS for 6 h for the LPS group (LPS). PBS was added to EBTr for a control group (CON). EBTr were pretreated with SB for 18 h followed by 6 h of LPS stimulation for the LSB group (LSB). Results showed that with LPS stimulation, the gene expression of TLR4, NF-κB, IL6, and IL8, as well as cytokine production of IL6 and TNF-α, were significantly increased compared with the CON group. In contrast, protein expression of IL10 was decreased. However, these inflammatory effects induced by LPS were reversed in the LSB group. Compared with the CON group, protein expression of TLR4, phospho-NF-κB p65, phospho-IκBα, and IL1α were increased in the LPS group and these were decreased in the LSB group. Similarly, increased nuclear translocation of phospho-NF-κB p65 in the LPS group was suppressed with SB pretreatment. In conclusion, SB can reduce inflammation induced by LPS in EBTr, and this positive effect is mediated through the TLR4 and NF-κB signaling pathway.

Butyrate: Connecting the gut-lung axis to the management of pulmonary disorders

Short-chain fatty acids (SCFAs) are metabolites released by bacterial components of the microbiota. These molecules have a wide range of effects in the microbiota itself, but also in host cells in which they are known for contributing to the regulation of cell metabolism, barrier function, and immunological responses. Recent studies indicate that these molecules are important players in the gut-lung axis and highlight the possibility of using strategies that alter their intestinal production to prevent or treat distinct lung inflammatory diseases. Here, we review the effects of the SCFA butyrate and its derivatives in vitro and in vivo on murine models of respiratory disorders, besides discussing the potential therapeutic use of butyrate and the other SCFAs in lung diseases.

Colonization of nasal cavities by Staphylococcus epidermidis mitigates SARS-CoV-2 nucleocapsid phosphoprotein-induced interleukin (IL)-6 in the lung

Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can trigger excessive interleukin (IL)-6 signalling, leading to a myriad of biological effects including a cytokine storm that contributes to multiple organ failure in severe coronavirus disease 2019 (COVID-19). Using a mouse model, we demonstrated that nasal inoculation of nucleocapsid phosphoprotein (NPP) of SARS-CoV-2 increased IL-6 content in bronchoalveolar lavage fluid (BALF). Nasal administration of liquid coco-caprylate/caprate (LCC) onto Staphylococcus epidermidis (S. epidermidis)-colonized mice significantly attenuated NPP-induced IL-6. Furthermore, S. epidermidis-mediated LCC fermentation to generate electricity and butyric acid that promoted bacterial colonization and activated free fatty acid receptor 2 (Ffar2) respectively. Inhibition of Ffar2 impeded the effect of S. epidermidis plus LCC on the reduction of NPP-induced IL-6. Collectively, these results suggest that nasal S. epidermidis is part of the first line of defence in ameliorating a cytokine storm induced by airway infection of SARS-CoV-2.

Prediction of the Mechanism of Sodium Butyrate against Radiation-Induced Lung Injury in Non-Small Cell Lung Cancer Based on Network Pharmacology and Molecular Dynamic Simulations and Molecular Dynamic Simulations

Background

Radiation-induced lung injury (RILI) is a severe side effect of radiotherapy for non-small cell lung cancer (NSCLC) ,and one of the major hindrances to improve the efficacy of radiotherapy. Previous studies have confirmed that sodium butyrate (NaB) has potential of anti-radiation toxicity. However, the mechanism of the protective effect of NaB against RILI has not yet been clarified. This study aimed to explore the underlying protective mechanisms of NaB against RILI in NSCLC through network pharmacology, molecular docking, molecular dynamic simulations and in vivo experiments.

Methods

The predictive target genes of NaB were obtained from the PharmMapper database and the literature review. The involved genes of RILI and NSCLC were predicted using OMIM and GeneCards database. The intersectional genes of drug and disease were identified using the Venny tool and uploaded to the Cytoscape software to identify 5 core target genes of NaB associated with RILI. The correlations between the 5 core target genes and EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors were analyzed using TIMER 2.0, TIMER and TISIDB databases. We constructed the mechanism maps of the 3 key signaling pathways using the KEGG database based on the results of GO and KEGG analyses from Metascape database. The 5 core target genes and drug were docked using the AutoDock Vina tool and visualized using PyMOL software. GROMACS software was used to perform 100 ns molecular dynamics simulation. Irradiation-induced lung injury model in mice were established to assess the therapeutic effects of NaB.

Results

A total of 51 intersectional genes involved in NaB against RILI in NSCLC were identified. The 5 core target genes were AKT1, TP53, NOTCH1, SIRT1, and PTEN. The expressions of the 5 core target genes were significantly associated with EGFR, PD-L1, immune infiltrates, chemokines and chemokine receptors, respectively. The results from GO analysis of the 51 intersectional genes revealed that the biological processes were focused on the regulation of smooth muscle cell proliferation, oxidative stress and cell death, while the three key KEGG pathways were enriched in PI3K-Akt signal pathway, p53 signal pathway, and FOXO signal pathway. The docking of NaB with the 5 core target genes showed affinity and stability, especially AKT1. In vivo experiments showed that NaB treatment significantly protected mice from RILI, with reduced lung histological damage. In addition, NaB treatment significantly inhibited the PI3K/Akt signaling pathway.

Conclusions

NaB may protect patients from RILI in NSCLC through multiple target genes including AKT1, TP53, NOTCH1, SIRT1 and PTEN, with multiple signaling pathways involving, including PI3K-Akt pathway, p53 pathway, and FOXO pathways. Our findings effectively provide a feasible theoretical basis to further elucidate the mechanism of NaB in the treatment of RILI.

The gut-lung axis in severe acute Pancreatitis-associated lung injury: The protection by the gut microbiota through short-chain fatty acids

The role of gut microbiota in regulating the intestinal homeostasis, as well as the pathogenesis of severe acute pancreatitis-associated lung injury (PALI) is widely recognized. The bioactive functions of metabolites with small molecule weight and the detail molecular mechanisms of PALI mediated by "gut-lung axis" have gradually raised the attentions of researchers. Several studies have proved that short-chain fatty acids (SCFAs) produced by gut microbiome play crucial roles and varied activities in the process of PALI. However, relevant reviews reporting SCFAs in the involvement of PALI is lacking. In this review, we firstly introduced the synthetic and metabolic pathways of SCFAs, as well as the transport and signal transduction routes in brief. Afterwards, we focused on the possible mechanisms and clues of SCFAs to participate in the fight against PALI which referred to the inhibition of pathogen proliferation, anti-inflammatory effects, enhancement of intestinal barrier functions, and the maintenance and regulation of immune homeostasis via pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). In addition, the latest reported pathological and physiological mechanisms of the gut-lung axis involved in PALI were reviewed. Finally, we summarized the potential therapeutic interventions of PALI by targeting SCFAs, including dietary fiber supplementation, direct supplementation of SCFAs/prebiotics/probiotics, and drugs administration, which is expected to provide new sights for clinical use in the future.

NF-κB and AMPK-Nrf2 pathways support the protective effect of polysaccharides from Polygonatum cyrtonema Hua in lipopolysaccharide-induced acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

The raw and honey-processed P. cyrtonema recorded in ancient classics of Chinese medicine as having the effect of moisturizing the lungs and relieving coughs, and it has also been proved to have therapeutic effects on lung diseases in modern research. Polysaccharides are the main components with biological activities in raw and honey-processed P. cyrtonema, but there is no research for their lung-protective effect.

AIM OF STUDY

This study aimed to investigate the protective effect and the possible mechanism of polysaccharides from raw and honey-processed P. cyrtonema in LPS-induced acute lung injury in mice.

MATERIALS AND METHODS

Polysaccharides, PCP and HPCP, were respectively separated and extracted from raw and honey-processed P. cyrtonema, and the molecular weight, monosaccharide composition and other basic chemical characteristics were analyzed by HPGCP, HPLC, FI-IR, and NMR. The model of ALI mice was established by intratracheal instillation of LPS. Moreover, the protective effects of PCP and HPCP for ALI mice were evaluated by detecting the wet-to-dry ratio and histopathology in the lungs, the content of inflammatory factors TNF-α, IL-6, IL-1β in BLAF, and the content of MPO and SOD in lung tissue. In addition, the lung-protective mechanism of PCP and HPCP was explored by detecting the levels of some proteins and mRNA related to inflammation and oxidative stress pathways.

RESULTS

PCP and HPCP with molecular weights of 8.842 × 10³ and 5.521 × 10³Da were mainly composed of three monosaccharides. Moreover, it is found that fructose and galactose were mainly β-D, and glucose was α-D. Both PCP and HPCP could significantly improve lung injury, reduce the level of inflammatory factors in BALF and the level of MPO in lung tissue, and increase the level of SOD. In addition, PCR and WB indicated that PCP and HPCP at least inhibited pulmonary inflammation through the NF-κB pathway, and reduced the occurrence of pulmonary oxidative stress through the AMPK-Nrf2 pathway.

CONCLUSIONS

Polysaccharides from raw and honey-processed P. cyrtonema had a protective effect in LPS-induced lung injury in mice. This effect may be related to the antioxidant and anti-inflammatory activities of PCP and HPCP in the lungs through the NF-κB pathway and AMPK-Nrf2 pathway. And HPCP seems to perform more than PCP.

Mechanistic insights into the amelioration effects of lipopolysaccharide-induced acute lung injury by baicalein: An integrated systems pharmacology study and experimental validation

BACKGROUND

Acute lung injury is an acute progressive respiratory failure caused by several of non-cardiogenic factors which involves in excessive amplification or uncontrolled inflammatory response.

OBJECTIVES

In this study, we investigated the protective effect of baicalein against acute lung injury induced by LPS and explored the underlying mechanisms.

METHODS

Forty-eight SPF male C57BL/6 mice were randomly divided into normal group, model group, dexamethasone group and baicalein low-dose, medium-dose and high-dose groups. After 5 days of adaptive feeding, the mice were intraperitoneally injected with LPS and dissected after 12 h. Hematoxylin-eosin staining, ELISA assay, immunofluorescence assay and Western-Blot were applied to appraise microstructural changes and protein expressions of lung tissues. Systems pharmacology study was used to evaluate the protection of baicalein on acute lung injury.

FINDINGS

The results showed that baicalein administration could significantly inhibit LPS-induced lung morphological changes, inhibit inflammatory response and pyroptosis. A total of forty-three potential targets of baicalein and acute lung injury were obtained. And PI3K-Akt, TNF and NF-κB were mainly signaling pathways. It is worth mentioning that this experiment also confirmed that NLRP3, caspase-1 and other inflammasome are involved in pyroptosis.

CONCLUSION

Baicalein has protected against LPS-induced lung tissues injury via inhibiting inflammatory response and pyroptosis.

Maternal oxidized soybean oil exposure in rats during lactation damages offspring kidneys via Nrf2/HO-1 and NF-κB signaling pathway

BACKGROUND

Cooking oil is an indispensable component of the human diet. However, oils usually undergo thermal oxidation. Oxidized soybean oil (OSO) has been shown to have detrimental effects on humans and has emerged as a root cause of many chronic diseases. The objective of this work was to evaluate the effects of puerpera exposure to OSO on kidney damage in the mother and offspring using lactating rats as an experimental model.

RESULTS

Pathological sections and ultrastructure showed that OSO exposure resulted in various levels of damage to lactating rats and their offspring. OSO induced oxidative stress in the kidneys of lactating rats, as evidenced by increased levels of hydrogen peroxide, interleukin (IL)-1β, and IL-8. OSO increased the activities of glutathione peroxidase and superoxide dismutase. OSO upregulated the expression of apoptosis-related genes, nuclear factor-erythroid 2-related factor 2 (Nrf2), and nuclear factor κB-related inflammatory factor genes. In the offspring of the OSO-exposed mothers, hydrogen peroxide, malondialdehyde, IL-6, and tumor necrosis factor-alpha contents were increased. Furthermore, OSO enhanced the levels of Nrf2, NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, and p65 and decreased B-cell lymphoma 2.

CONCLUSION

These findings indicated that the kidneys of two generations of rats were compromised by oxidative damage when fed OSO during lactation. This study provides evidence for increasing the genes expression of the Nrf2/heme oxygenase 1 pathway to alleviate the kidney damage caused by OSO in the mother and offspring. © 2021 Society of Chemical Industry.

Hesperidin protects against cisplatin-induced cardiotoxicity in mice by regulating the p62-Keap1-Nrf2 pathway

Hesperidin (HES) is an abundant and economical dietary bioflavonoid, and it has several pharmacological properties such as antioxidant activity and powerful cardiac protection. However, HES protection against cisplatin (CP)-induced cardiotoxicity and its mechanism have not been fully clarified. The current study was performed to further elucidate the mechanism of HES against CP-induced cardiotoxicity. Mice were orally administered HES (100 or 300 mg kg^-1 day^-1) for 7 consecutive days and then injected intraperitoneally (i.p.) with CP (5 mg kg^-1) on days 3 and 6. On day 8, mice were anaesthetised with sodium pentobarbital (50 mg kg^-1, i.p.), and blood and heart samples were collected for analysis. HES treatment reduced CP-induced cardiac pathologic damage and leakage of the myocardial markers cardiac troponin I (cTnI), creatine kinase (CK), and lactate dehydrogenase (LDH). HES treatment reduced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), which is an oxidative product, and increased antioxidant marker levels including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). HES also reduced the CP-induced release of the inflammatory factors tumour necrosis factor (TNF)-α and interleukin (IL)-6. Additionally, HES treatment up-regulated the expression of anti-apoptotic protein Bcl-2 and down-regulated the expression of pro-apoptotic proteins Bax and Caspase-3. HES treatment also improved the expression of pathway proteins p62 and Nrf2 and inhibited the increase in CP-induced Keap1 expression. Thus, HES may provide protection against CP cardiotoxicity through inhibiting oxidative stress, inflammation, and apoptosis, which may contribute to activation of the p62-Keap1-Nrf2 signalling pathway. These findings suggest that HES may be a promising protective agent against CP cardiotoxicity in future anticancer clinical practice.

Cordyceps militaris Modulates Intestinal Barrier Function and Gut Microbiota in a Pig Model

This study investigated the effects of Cordyceps militaris (CM) on intestinal barrier function and gut microbiota in a pig model. A total of 160 pigs were randomly allocated to either a control group (fed the basal diet) or a CM group (fed the basal diet supplemented with 300 mg/kg CM). CM improved intestinal morphology and increased the numbers of goblet cells and intraepithelial lymphocytes. CM also elevated the expression of zona occluden-1, claudin-1, mucin-2 and secretory immunoglobulin A. Furthermore, the mucosal levels of pro-inflammatory cytokines were downregulated while the levels of anti-inflammatory cytokines were upregulated in the CM group. Mechanistically, CM downregulated the expression of key proteins of the TLR4/MyD88/NF-κB signaling pathway. Moreover, CM altered the colonic microbial composition and increased the concentrations of acetate and butyrate. In conclusion, CM can modulate the intestinal barrier function and gut microbiota, which may provide a new strategy for improving intestinal health.

Berberine Ameliorates Inflammation in Acute Lung Injury via NF-κB/Nlrp3 Signaling Pathway

The inflammatory response is the key pathophysiological character of acute lung injury (ALI). Berberine (BBR), a natural quaternary ammonium alkaloid, plays a functional role in anti-inflammation both in vitro and in vivo. However, the underlying mechanism between BBR and ALI has not been expounded. Here, we found that BBR improved the permeability of pulmonary and repressed the inflammatory factors in the lipopolysaccharides (LPSs)-induced ALI model. We demonstrated that BBR could suppress the expression of phosphorylated nuclear factor-kappa B (NF-κB) and further restrain the downstream gene nucleotide-binding domain and leucine-rich repeat protein-3 (Nlrp3). Moreover, we also revealed that BBR could directly interact with Nlrp3 protein. After knocked down of Nlrp3 by using siRNA, the protective role of BBR was abrogated in vitro. The expression of IL-1β and IL-18 was downregulated by BBR via the two signaling pathways. Notably, in Nlrp3 deficient mice, the protective effect of BBR was abolished. These findings demonstrate that BBR has a depressant effect on inflammatory response caused by LPS via regulating NF-κB/Nlrp3 signaling pathway, providing a potential therapeutic strategy in ALI.

Role of genistein on the yield, structure and immunomodulatory activity of Monascus exopolysaccharides

Manipulating the structures, physicochemical properties, and monosaccharide compositions of exopolysaccharides (EPS) isolated from microorganisms has been reported to enhance their biological activities. Hence, the aim of this work was to examine the effects of genistein addition during fermentation on the amount, physicochemical properties, and immunomodulatory activity of EPS secreted by M. purpureus. Results showed that genistein addition significantly increased M. purpureus biomass and EPS yield to 2.42 g L^-1 and 6.08 g L^-1, respectively, and affected the physicochemical properties and structures of EPS. Furthermore, EPS produced by genistein-treated M. purpureus (G-EMP) improved the immunomodulatory activity of RAW264.7 macrophages by increasing the secretion of nitric oxide and cytokines. Moreover, phospho-Jun N-terminal kinase (p-JNK), phospho-extracellular regulated protein kinase (p-ERK), phospho-p38 (p-p38) mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) phospho-p65 (p65) proteins were remarkably upregulated by G-EMP stimulation, blocking Toll-like receptor 4 (TLR4) that dramatically reduced the pinocytic and phagocytic capacities. Overall, these findings provide potential rationales for the application of genistein in improving the EPS yield of M. purpureus.

Gut-Lung Crosstalk in Sepsis-Induced Acute Lung Injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common acute and severe cases of the respiratory system with complicated pathogenesis and high mortality. Sepsis is the leading indirect cause of ALI/ARDS in the intensive care unit (ICU). The pathogenesis of septic ALI/ARDS is complex and multifactorial. In the development of sepsis, the disruption of the intestinal barrier function, the alteration of gut microbiota, and the translocation of the intestinal microbiome can lead to systemic and local inflammatory responses, which further alter the immune homeostasis in the systemic environment. Disruption of homeostasis may promote and propagate septic ALI/ARDS. In turn, when ALI occurs, elevated levels of inflammatory cytokines and the shift of the lung microbiome may lead to the dysregulation of the intestinal microbiome and the disruption of the intestinal mucosal barrier. Thus, the interaction between the lung and the gut can initiate and potentiate sepsis-induced ALI/ARDS. The gut–lung crosstalk may be a promising potential target for intervention. This article reviews the underlying mechanism of gut-lung crosstalk in septic ALI/ARDS.

Ethyl ferulate protects against lipopolysaccharide-induced acute lung injury by activating AMPK/Nrf2 signaling pathway

Ethyl ferulate (EF) is abundant in Rhizoma Chuanxiong and grains (e.g., rice and maize) and possesses antioxidative, antiapoptotic, antirheumatic, and anti-inflammatory properties. However, its effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is still unknown. In the present study, we found that EF significantly alleviated LPS-induced pathological damage and neutrophil infiltration and inhibited the gene expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in murine lung tissues. Moreover, EF reduced the gene expression of TNF-α, IL-1β, IL-6, and iNOS and decreased the production of NO in LPS-stimulated RAW264.7 cells and BMDMs. Mechanistic experiments revealed that EF prominently activated the AMPK/Nrf2 pathway and promoted Nrf2 nuclear translocation. AMPK inhibition (Compound C) and Nrf2 inhibition (ML385) abolished the beneficial effect of EF on the inflammatory response. Furthermore, the protective effect of EF on LPS-induced ALI was not observed in Nrf2 knockout mice. Taken together, the results of our study suggest that EF ameliorates LPS-induced ALI in an AMPK/Nrf2-dependent manner. These findings provide a foundation for developing EF as a new anti-inflammatory agent for LPS-induced ALI/ARDS therapy.

Microbiota-gut-brain axis and Alzheimer's disease: Implications of the blood-brain barrier as an intervention target

The microbiota-gut-brain axis has emerged as a focal point of biomedical research. Alterations of gut microbiota are involved in not only various immune/inflammatory disorders but also neurological disorders including Alzheimer's disease (AD). The initial stage of the involvement of gut microbiota in the pathogenesis of AD may be the dysfunction of the blood-brain barrier (BBB). Gut microbiota-derived products in the circulation can worsen the BBB integrity, easily cross the disrupted BBB and enter the brain to promote pathological changes in AD. In this review, we first summarize the current evidence of the associations among gut microbiota, AD, and BBB integrity. We then discuss the mechanism of gut microbiota on BBB dysfunction with a focus on bacteria-derived lipopolysaccharide and exosomal high-mobility group box 1. Novel insights into the modification of the BBB as an intervention approach for AD are highlighted as well.

Glycoproteins From Rabdosia japonica var. glaucocalyx Regulate Macrophage Polarization and Alleviate Lipopolysaccharide-Induced Acute Lung Injury in Mice via TLR4/NF-κB Pathway

Background and Aims:Rabdosia japonica var. glaucocalyx is a traditional Chinese medicine (TCM) for various inflammatory diseases. This present work aimed to investigate the protective effects of R. japonica var. glaucocalyx glycoproteins on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the potential mechanism.

Methods: Glycoproteins (XPS) were isolated from R. japonica var. glaucocalyx, and homogeneous glycoprotein (XPS5-1) was purified from XPS. ANA-1 cells were used to observe the effect of glycoproteins on the secretion of inflammatory mediators by enzyme-linked immunosorbent assay (ELISA). Flow cytometry assay, immunofluorescence assay, and Western blot analysis were performed to detect macrophage polarization in vitro. The ALI model was induced by LPS via intratracheal instillation, and XPS (20, 40, and 80 mg/kg) was administered intragastrically 2 h later. The mechanisms of XPS against ALI were investigated by Western blot, ELISA, and immunohistochemistry.

Results:In vitro, XPS and XPS5-1 downregulated LPS-induced proinflammatory mediators production including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and nitric oxide (NO) and upregulated LPS-induced IL-10 secretion. The LPS-stimulated macrophage polarization was also modulated from M1 to M2. In vivo, XPS maintained pulmonary histology with significantly reducing protein concentration and numbers of mononuclear cells in bronchoalveolar lavage fluid (BALF). The level of IL-10 in BALF was upregulated by XPS treatment. The level of cytokines including TNF-α, IL-1β, and IL-6 was downregulated. XPS also decreased infiltration of macrophages and polymorphonuclear leukocytes (PMNs) in lung. XPS suppressed the expression of key proteins in the TLR4/NF-κB signal pathway.

Conclusion: XPS was demonstrated to be a potential agent for treating ALI. Our findings might provide evidence supporting the traditional application of R. japonica var. glaucocalyx in inflammation-linked diseases.

Inflammation response after the cessation of chronic arsenic exposure and post-treatment of natural astaxanthin in liver: potential role of cytokine-mediated cell-cell interactions

Ongoing groundwater arsenic contamination throughout China was first recognized in the 1960s. Groundwater arsenic contamination is a high risk for human and animal health worldwide. Apart from drinking water, diet is the second pathway for arsenic to enter the human body and eventually cause liver injury. Natural astaxanthin extracted from the green algae Haematococcus pluvialis has dominated the nutraceutical market for potential health benefits. Nevertheless, the molecular mechanism underlying the protective effect post astaxanthin against arsenic-induced hepatotoxicity remains largely obscure. In this study, we investigate the effect of natural astaxanthin (derived from Haemotococcus pluvialis) on oxidative stress and liver inflammatory response in rats after the cessation of chronic arsenic exposure. Wistar rats were given astaxanthin (250 mg kg-1) daily for 2 weeks after the cessation of exposure to sodium arsenite (300 μg L-1, drinking water, 24 weeks) by intragastric administration. The results showed that post treatment with astaxanthin attenuated liver injury induced by long-term exposure to arsenic in rats. Most importantly, post treatment with astaxanthin decreased the increasing of inflammatory cytokine NF-κB, tumor necrosis factor-α, interleukin-1β, oxidative stress level, and total arsenic content in livers of rats exposed to arsenic. In addition, post treatment with astaxanthin reversed the increasing of protein levels of alpha-smooth muscle actin and collagen Iα1, which are the activation markers of hepatic stellate cells (HSCs). Collectively, these data demonstrate that post astaxanthin treatment attenuates inflammation response in the liver after the cessation of chronic arsenic exposure via inhibition of cytokine-mediated cell-cell interactions. Daily ingestion of natural astaxanthin might be a potential and beneficial candidate for the treatment of liver damage after the cessation of chronic exposure to sodium arsenite.

Histone Deacetylase 7 Inhibition in a Murine Model of Gram-Negative Pneumonia-Induced Acute Lung Injury

BACKGROUND

Pulmonary infections remain the most common cause of Acute Respiratory Distress Syndrome (ARDS), a pulmonary inflammatory disease with high mortality, for which no targeted therapy currently exists. We have previously demonstrated an ameliorated syndrome with early, broad spectrum Histone Deacetylase (HDAC) inhibition in a murine model of gram-negative pneumonia-induced Acute Lung Injury (ALI), the underlying pulmonary pathologic phenotype leading to ARDS. With the current project we aim to determine if selective inhibition of a specific HDAC leads to a similar pro-survival phenotype, potentially pointing to a future therapeutic target.

METHODS

C57Bl/6 mice underwent endotracheal instillation of 30×10Escherichia coli (strain 19138) versus saline (n = 24). Half the infected mice were administered Trichostatin A (TSA) 30 min later. All animals were sacrificed 6 h later for tissue sampling and HDAC quantification, while another set of animals (n = 24) was followed to determine survival. Experiments were repeated with selective siRNA inhibition of the HDAC demonstrating the greatest inhibition versus scrambled siRNA (n = 24).

RESULTS

TSA significantly ameliorated the inflammatory phenotype and improved survival in infected-ALI mice, and HDAC7 was the HDAC with the greatest transcription and protein translation suppression. Similar results were obtained with selective HDAC7 siRNA inhibition compared with scrambled siRNA.

CONCLUSION

HDAC7 appears to play a key role in the inflammatory response that leads to ALI after gram-negative pneumonia in mice.

Is butyrate a natural alternative to dexamethasone in the management of CoVID-19?

Coronavirus disease 2019 (CoVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 has affected more than 100 million lives. Severe CoVID-19 infection may lead to acute respiratory distress syndrome and death of the patient, and is associated with hyperinflammation and cytokine storm. The broad spectrum immunosuppressant corticosteroid, dexamethasone, is being used to manage the cytokine storm and hyperinflammation in CoVID-19 patients. However, the extensive use of corticosteroids leads to serious adverse events and disruption of the gut-lung axis. Various micronutrients and probiotic supplementations are known to aid in the reduction of hyperinflammation and restoration of gut microbiota. The attenuation of the deleterious immune response and hyperinflammation could be mediated by short chain fatty acids produced by the gut microbiota. Butyric acid, the most extensively studied short chain fatty acid, is known for its anti-inflammatory properties. Additionally, butyric acid has been shown to ameliorate hyperinflammation and reduce oxidative stress in various pathologies, including respiratory viral infections. In this review, the potential anti-inflammatory effects of butyric acid that aid in cytokine storm depletion, and its usefulness in effective management of critical illness related to CoVID-19 have been discussed.

The second phase of brain trauma can be controlled by nutraceuticals that suppress DAMP-mediated microglial activation

INTRODUCTION

A delayed second wave of brain trauma is mediated in large part by microglia that are activated to a pro-inflammatory M1 phenotype by DAMP proteins released by dying neurons. These microglia can promote apoptosis or necrosis in neighboring neurons by producing a range of pro-inflammatory cytokines and the deadly oxidant peroxynitrite. This second wave could therefore be mitigated with agents that blunt the post-traumatic M1 activation of microglia and that preferentially promote a pro-healing M2 phenotype.

AREAS COVERED

The literature on nutraceuticals that might have clinical potential in this regard.

EXPERT OPINION

The chief signaling pathway whereby DAMPs promote M1 microglial activation involves activation of toll-like receptor 4 (TLR4), NADPH oxidase, NF-kappaB, and the stress activated kinases JNK and p38. The green tea catechin EGCG can suppress TLR4 expression. Phycocyanobilin can inhibit NOX2-dependent NADPH oxidase, ferulate and melatonin can oppose pro-inflammatory signal modulation by NADPH oxidase-derived oxidants. Long-chain omega-3 fatty acids, the soy isoflavone genistein, the AMPK activator berberine, glucosamine, and ketone bodies can down-regulate NF-kappaB activation. Vitamin D activity can oppose JNK/p38 activation. A sophisticated program of nutraceutical supplementation may have important potential for mitigating the second phase of neuronal death and aiding subsequent healing.

Effects of sodium butyrate supplementation on inflammation, gut microbiota, and short-chain fatty acids in Helicobacter pylori-infected mice

BACKGROUND

Inflammation induced by Helicobacter pylori (H. pylori) infection is the basis for the pathogenesis of H. pylori. Butyric acid, a diet-related microbial-associated metabolite, is connected to inflammation, metabolic syndrome, and other diseases. Several studies have indicated the effects of sodium butyrate (SB) against bacteria; however, the effects of SB on the main virulence factors of H. pylori, H. pylori-induced inflammation, and gut microbiota composition remain unclear.

MATERIALS AND METHODS

SB was supplemented in H. pylori coculture and administered to mice infected with H. pylori. The effects of SB intake on inflammation, gut microbiota composition, and short-chain fatty acids (SCFAs) in H. pylori-infected mice were assessed.

RESULTS

The in vitro experiments demonstrated that SB not only inhibited the growth of H. pylori but also decreased the mRNA expression of CagA and VacA. SB intake reduced the production of virulence factors in H. pylori-infected mice, inhibited the IκBα/NF-κB pathway by reducing the expression of Toll-like receptors (TLRs), and reduced the production of TNF-α and IL-8. Further analysis demonstrated that H. pylori infection altered the relative abundance of the intestinal microbial community in mice. The level of SCFAs in the feces of H. pylori-infected mice was changed, although the intake of SB did not obviously change the level of SCFAs.

CONCLUSIONS

Our study showed that SB may decrease H. pylori-induced inflammation by inhibiting the viability and virulence of H. pylori and may reduce inflammation in association with the gut microbiota in H. pylori-infected mice. This study may provide novel insights into the mechanisms by which SB, a diet-related microbial-associated metabolite, affects H. pylori-induced disease development.

Paeonol attenuates inflammation by confining HMGB1 to the nucleus

Inflammation is a biological process that exists in a large number of diseases. If the magnitude or duration of inflammation becomes uncontrolled, inflammation may cause pathological damage to the host. HMGB1 and NF-κB have been shown to play pivotal roles in inflammation-related diseases. New drugs aimed at inhibiting HMGB1 expression have become a key research focus. In the present study, we showed that paeonol (Pae), the main active component of Paeonia suffruticosa, decreases the expression of inflammatory cytokines and inhibits the translocation of HMGB1 induced by lipopolysaccharide (LPS). By constructing HMGB1-overexpressing (HMGB1⁺ ) and HMGB1-mutant (HMGB1^m ) RAW264.7 cells, we found that the nuclear HMGB1 could induce an LPS-tolerant state in RAW264.7 cells and that paeonol had no influence on the expression of inflammatory cytokines in HMGB1^m RAW264.7 cells. In addition, the anti-inflammatory property of paeonol was lost in HMGB1 conditional knockout mice, indicating that HMGB1 is a target of paeonol and a mediator through which paeonol exerts its anti-inflammatory function. Additionally, we also found that HMGB1 and P50 competitively bound with P65, thus inactivating the NF-κB pathway. Our research confirmed the anti-inflammation property of paeonol and suggests that inhibiting the translocation of HMGB1 could be a new strategy for treating inflammation.