Individual Variabilities in Adipose Stem Cell Proliferation, Gene Expression and Responses to Lipopolysaccharide Stimulation.

Adipose stem cells (ASCs) are reported to play a role in normal physiology as well as in inflammation and disease. The objective of this work was to elucidate inter-individual differences in growth, gene expression and response to inflammatory stimuli in ASCs from different donors. Human ASC1 (male donor) and ASC2 (female donor) were purchased from Lonza (Walkersville, MD). Cell proliferation was determined by the sulforhodamine B assay. After time-dependent treatment of ASCs with or without bacterial lipopolysaccharide (LPS), marker gene mRNAs for proliferation, steroid hormones, and xenobiotic and immune pathways were determined using RT-PCR, and secreted cytokine levels in media were measured using the Bio-Plex cytokine assay kit. ASCs from both donors expressed androgen receptors but not estrogen receptors. ASC2 had a 2-fold higher proliferation rate and a 6-fold higher level of proliferation marker Ki67 mRNA than ASC1. ASC2 exhibited significantly greater fold induction of TNF-α and CCL2 by LPS compared to ASC1. TNF-α and GM-CSF protein levels were also significantly higher in the LPS-induced ASC2 media, but IL-6 secretion was higher in the LPS-induced ASC1 media. Our findings suggest that inter-individual variability and/or possible sex differences exist in ASCs, which may serve as a key determinant to inflammatory responses of ASCs.

Modulation of CXC-motif chemokine receptor 7, but not 4, expression is related to migration of the human prostate cancer cell LNCaP: regulation by androgen and inflammatory stimuli.

OBJECTIVE: To elucidate the regulation, function of the chemokine CXC-motif ligand 12 (CXCL12) and its receptors (CXCR) 4 and 7 in prostate cancer tumor microenvironment. MATERIAL: In-silico-analysis of expression in prostate cancer tissues. In-vitro comparison, testing of regulation in human prostate cancer cells LNCaP, DU145, and PC3. TREATMENT: Dihydrotestosterone (DHT) treatments (0-10 nM) were for 0-48 h. The inflammatory agent Flagellin treatment (20 ng/ml) was for 2 h. Migration assays were performed for 24 h using 10 ng/ml CXCL12. METHODS: Real-time PCR, western analysis, and migration assays were used to determine mRNA, protein, and functional changes, respectively. RESULTS: Malignant prostate cancer tissues exhibit higher CXCR4/7 mRNA ratio, and higher CXCR7 mRNA levels were detected in the androgen-responsive LNCaP cells. Putative androgen-responsive elements were identified in CXCR4, 7 gene, and exposure to DHT, flagellin increased CXCR4 mRNA but decreased CXCR7 mRNA levels in LNCaP cells. Androgen receptor siRNA significantly attenuated the effects of DHT on CXCR4, 7 mRNA in LNCaP cells. However, DHT and flagellin only decrease CXCR7 protein and additively increased migration of LNCaP cells towards CXCL12. CONCLUSIONS: Down regulation of CXCR7 protein by DHT and flagellin increased migration, supporting CXCR7 as decoy receptor counteracting CXCL12/CXCR4-mediated migration in prostate cancer cells.

Elucidating the Role of CD84 and AHR in Modulation of LPS-Induced Cytokines Production by Cruciferous Vegetable-Derived Compounds Indole-3-Carbinol and 3,3'-Diindolylmethane.

Modulation of the immune system by cancer protective food bioactives has preventive and therapeutic importance in prostate cancer, but the mechanisms remain largely unclear. The current study tests the hypothesis that the diet-derived cancer protective compounds, indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM), affect the tumor microenvironment by regulation of inflammatory responses in monocytes and macrophages. We also ask whether I3C and DIM act through the aryl hydrocarbon (AHR)-dependent pathway or the signaling lymphocyte activation molecule (SLAM) family protein CD84-mediated pathway. The effect of I3C and DIM was examined using the human THP-1 monocytic cell in its un-differentiated (monocyte) and differentiated (macrophage) state. We observed that I3C and DIM inhibited lipopolysaccharide (LPS) induction of IL-1ß mRNA and protein in the monocyte form but not the macrophage form of THP-1. Interestingly, CD84 mRNA but not protein was inhibited by I3C and DIM. AHR siRNA knockdown experiments confirmed that the inhibitory effects of I3C and DIM on IL-1ß as well as CD84 mRNA are regulated through AHR-mediated pathways. Additionally, the AHR ligand appeared to differentially regulate other LPS-induced cytokines expression. Hence, cross-talk between AHR and inflammation-mediated pathways, but not CD84-mediated pathways, in monocytes but not macrophages may contribute to the modulation of tumor environments by I3C and DIM in prostate cancer.

Phospholipid-rich krill oil promotes intestinal health by strengthening beneficial gut microbial interactions in an infectious colitis model.

Krill oil (KO) is rich in bioactive ingredients including phospholipids, omega-3 fatty acids, and astaxanthin. While health benefits and roles of KO in modulating lipid metabolism are well documented, its ability to alleviate symptoms related to infectious colitis and modulate gut microbial interactions is still largely unknown. Here we used a multi-omics approach, including transcriptome, microbiome, and metabolome analyses, to understand how KO mediates gut microbial interactions and promotes epithelial healing in an infectious colitis model. KO reversed the infection-induced intestinal hyperplasia to baseline. KO dampened intestinal inflammation via multiple targets, mediating several proinflammatory pathways, including IL17 signaling, and reducing luminal histamine levels. KO supplementation enriched butyrate-producing bacteria, including Roseburia and Clostridium, and strengthened beneficial microbial interactions in the gut microbial community. Supplementation with phospholipid-rich KO also increased microbial phylogenetic diversity. KO enhanced mucosal barrier function by increasing the production of Muc6 and the antimicrobial peptide, Leap2. KO played an active role during epithelial healing by inhibiting the expression of granzyme K while increasing the expression of a colitis protective factor, Dclk1. Together, our findings demonstrate that KO rich in omega-3 phospholipids can play a protective role in infectious colitis and should be considered a dietary option for promoting gut health.

Identification and elucidation of cross talk between SLAM Family Member 7 (SLAMF7) and Toll-like receptor (TLR) pathways in monocytes and macrophages.

To further elucidate the expression, regulation and function of Signaling Lymphocytic Activation Molecule Family (SLAMF) protein members in human monocytes and macrophages. Un-differentiated monocytic THP-1 cell (u-THP-1) and differentiated THP-1 macrophage (d-THP-1) were used as culture models in the study. Responses of cells to the differentiation agents phorbol ester (25 ng/ml) and TLR (Toll-like receptor) ligands were assessed. RT-PCR and Western blot analysis were used to determine mRNA and protein level. Pro-inflammatory cytokine mRNA expression levels and phagocytosis were used as functional markers. Data analyzed using t-test, one-way or two-way ANOVA followed by post hoc test. SLAMFs were differentially expressed in THP-1 cells. Differentiation of u-THP-1 to d-THP-1 led to significantly higher SLAMF7 mRNA and protein levels than other SLAMF. In addition, TLR stimuli increased SLAMF7 mRNA expression but not protein expression. Importantly, SLAMF7 agonist antibody and TLR ligands synergistically increased the mRNA expression levels of IL-1ß, IL-6 and TNF-α, but had no effect on phagocytosis. SLAMF7 knocked-down in d-THP-1 significantly lowered TLR-induced mRNA expressions of pro-inflammatory markers. SLAM family proteins are differentially regulated by differentiation and TLRs. SLAMF7 enhanced TLR-mediated induction of pro-inflammatory cytokines in monocytes and macrophages but not phagocytosis.

Ellagitannin Punicalagin Disrupts the Pathways Related to Bacterial Growth and Affects Multiple Pattern Recognition Receptor Signaling by Acting as a Selective Histone Deacetylase Inhibitor.

Punicalagin (PA) is a key ellagitannin abundant in pomegranate with wide-ranging biological activities. In this study, we examined the biological processes by which PA regulates bacterial growth and inflammation in human cells using multiomics and molecular docking approaches. PA promoted macrophage-mediated bacterial killing and inhibited the growth of Citrobacter rodentium by inducing a distinct metabolome pattern. PA acted as a selective regulator of histone deacetylases (HDACs) and affected 37 pathways in macrophages, including signaling mediated by pattern recognition receptors, such as Toll-like and NOD-like receptors. In silico simulation showed that PA can bind with high affinity to HDAC7. PA downregulated HDAC7 at both mRNA and protein levels and resulted in a decrease in the level of histone 3 lysine 27 acetylation. Our findings provide evidence that PA exerts its biological effects via multiple pathways, which can be exploited in the development of this bioactive food ingredient for disease management.

Multi-omics analysis detected multiple pathways by which pomegranate punicalagin exerts its biological effects in modulating host-microbiota interactions in murine colitis models.

As one of the key bioactive food ingredients in pomegranate, punicalagin (PA) possesses wide-ranging functional activities. However, the knowledge on PA-modulated microbial interactions and their physiological relevance in the gastrointestinal tract is limited. In this study, the modulating effects of PA on host-microbiota interactions were examined using multi-omics approaches in two colitis models. In a chemical colitis model, PA ingestion dampened intestinal inflammation and repressed gut microbial diversity. PA significantly reversed multiple lipids and γ-glutamyl amino acids from elevated levels in colitis mice to the baseline. Anti-inflammatory and microbiota-modulating effects of PA were further validated in an infectious colitis model induced by Citrobacter rodentium, in which PA also restored the microbial dysbiosis index to the baseline and promoted microbial interactions. Multiple microbial signatures with high predictive accuracy for key colitis pathophysiological parameters were identified, which can be developed as biomarkers for monitoring the efficacy of PA-containing functional foods in promoting gut health. Our findings should facilitate the exploitation of dual applications of PA as a bioactive food ingredient and a therapeutic agent.

Red cabbage microgreen modulation of gut microbiota is associated with attenuation of diet-induced obesity risk factors in a mouse model.

Cruciferous vegetable microgreens, such as red cabbage microgreens (RCMG), are of special interest due to their well-documented health-promoting effects compared to their mature counterparts. However, little is known of the biological effects of microgreens. The present study used a rodent diet-induced obesity model to investigate the effect of consuming RCMG on the gut microbiota. We found that the consumption of RCMG exerted profound impacts on the microbial composition in mice. Specifically, the species diversity of mice on both low fat (LF) and high fat (HF) diets was significantly increased by the consumption of RCMG. In comparison with the LF control group, the intake of RCMG increased the gut Firmicutes/Bacteroidetes (F/B) ratio. Furthermore, an unidentified species of the Clostridiales order, increased by RCMG, was found to be negatively correlated with the hepatic cholesterol ester level in mice (r = -0.43, p < 0.05). In addition, RCMG significantly inhibited HF diet-induced elevation of the genus AF12, of which the abundance was positively correlated with the body weight gain (r = 0.52, p < 0.01) and fecal bile acid in mice (r = 0.59, p < 0.01). Overall, our results demonstrated that the consumption of RCMG in the diet can alter the gut microbiota, and attenuation of HF diet-induced body weight gain and altered cholesterol metabolism may be mediated through regulation of the gut microbiota.

Biological pathways via which the anthocyanin malvidin alleviated the murine colitis induced by Citrobacter rodentium.

Enteropathogenic E. coli (EPEC) is a causal agent for diarrheal diseases and contributes to morbidity and mortality in children under the age of five years. The emergence and rapid spread of antibiotic resistant EPEC strains necessitate the search for novel alternatives to antibiotics. In this study, we used Citrobacter rodentium, a natural mouse pathogen that mimics many aspects of human EPEC infections, to investigate the antimicrobial properties of the blueberry anthocyanin malvidin 3-glucoside (MG) using a multi-omics approach. MG supplementation reversed the bodyweight loss induced by C. rodentium infection and improved colonic hyperplasia and histopathological scores. In the colon tissue, MG supplementation significantly increased the expression of Hace1, a key regulator of TNFα-driven signaling, and impacted multiple pathways, such as TGFß signaling. MG partially restored C. rodentium-induced microbial dysbiosis and significantly enhanced the abundance of the probiotic Bifidobacterium animalis. Moreover, MG disrupted the interactions of E. coli with other gut microbes. MG significantly mediated several host- and microbiota-derived metabolites, such as cytosine, ureidopropionic acid, and glutaric acid. MG normalized the bioactive lipid oleoylethanolamine, a member of the endocannabinoid system, from the dysregulated level in infected mice, directly contributing to its overall beneficial effects. Our findings provided novel insights into molecular processes via which the flavonoid malvidin exerts its biological effects in the gastrointestinal tract.

Red Cabbage Modulates Composition and Co-Occurrence Networks of Gut Microbiota in a Rodent Diet-Induced Obesity Model.

Red cabbage (RC), a cruciferous vegetable rich in various bioactive substances, can significantly reduce the risk factors of several non-communicable diseases, but the mechanism underlying the biological effects of RC remains unclear. Furthermore, mechanisms that operate through the regulation of gut microbiota also are not known. Given the relationships between diet, gut microbiota, and health, a diet-induced mice obesity model was used to elucidate the influence of RC on gut microbial composition and bacteria-bacteria interactions in mice. After 24 h of dietary intervention, a high-fat (HF) diet with the intake of RC led to increased Firmicutes/Bacteroidetes (F/B) ratios in the feces of mice. RC also reduced the relative abundance of Bifidobacteria, Lactobacillus, and Akkermansia muciniphila in mice fed a low-fat (LF) diet. After 8-weeks of dietary intervention, RC significantly changed the structure and the ecological network of the gut microbial community. Particularly, RC inhibited an HF-diet-induced increase in AF12 in mice, and this genus was positively correlated with body weight, low-density lipoprotein level, and fecal bile acid of mice. Unclassified Clostridiales, specifically increased via RC consumption, were also found to negatively correlate with hepatic free cholesterol levels in mice. Overall, our results demonstrated that RC modulating gut microbial composition and interactions are associated with the attenuation of HF-diet-induced body weight gain and altered cholesterol metabolism in mice.

Discovery of potent, soluble and orally active TRPV1 antagonists. Structure-activity relationships of a series of isoxazoles.

Systematic optimisation of a poorly soluble lead series of isoxazole-3-carboxamides was conducted. Substitution of the 4-position with specific polar functionality afforded the requisite balance of potency, solubility and physicochemical properties. Compound 21a was found to be efficacious in the rat Capsaicin Hargreaves assay following oral administration.

Structure-activity studies of a novel series of isoxazole-3-carboxamide derivatives as TRPV1 antagonists.

Optimisation of a screening hit incorporating both TRPV1 activity and solubility was conducted. Substitution of the isoxazole-3-carboxamide with the bespoke 1S, 3R-3-aminocyclohexanol motif afforded the requisite balance of potency and solubility. Compounds 32 and 40 were found to have antihyperalgesic effects in the rat CFA Hg assay and induce a mechanism based hyperthermia.

Transcriptomic Analysis of LNCaP Tumor Xenograft to Elucidate the Components and Mechanisms Contributed by Tumor Environment as Targets for Dietary Prostate Cancer Prevention Studies.

LNCaP athymic xenograft model has been widely used to allow researchers to examine the effects and mechanisms of experimental treatments such as diet and diet-derived cancer preventive and therapeutic compounds on prostate cancer. However, the biological characteristics of human LNCaP cells before/after implanting in athymic mouse and its relevance to clinical human prostate outcomes remain unclear and may dictate interpretation of biological efficacies/mechanisms of diet/diet-derived experimental treatments. In this study, transcriptome profiles and pathways of human prostate LNCaP cells before (in vitro) and after (in vivo) implanting into xenograft mouse were compared using RNA-sequencing technology (RNA-seq) followed by bioinformatic analysis. A shift from androgen-responsive to androgen nonresponsive status was observed when comparing LNCaP xenograft tumor to culture cells. Androgen receptor and aryl-hydrocarbon pathway were found to be inhibited and interleukin-1 (IL-1) mediated pathways contributed to these changes. Coupled with in vitro experiments modeling for androgen exposure, cell-matrix interaction, inflammation, and hypoxia, we identified specific mechanisms that may contribute to the observed changes in genes and pathways. Our results provide critical baseline transcriptomic information for a tumor xenograft model and the tumor environments that might be associated with regulating the progression of the xenograft tumor, which may influence interpretation of diet/diet-derived experimental treatments.

Effects of Differences in Resistant Starch Content of Rice on Intestinal Microbial Composition.

The aim of this study was to evaluate the effects of resistant starch (RS) and fat levels on the gut microbiome in C57BL/6 mice. Three levels of RS from three varieties of rice were the major source of carbohydrates and fat levels were low (10%) and high (39%). We confirmed that RS decreased the Firmicutes to Bacteroidetes ratio, increased SCFA production by higher Bacteroidaceae and S24-7 abundance, and enriched predicted gene families of glycosidases and functional pathways associated with carbohydrate and glycan metabolism. We also found correlations between microbial taxa and tissue gene expression related to carbohydrate and lipid metabolism. Moreover, increasing RS levels resulted in a molecular ecological network with enhanced modularity and interspecific synergy, which is less sensitive to high fat intervention. Overall, RS as low as 0.44% from cooked rice can modulate gut microbiome in mice, which correlated to a protective effect against deleterious effects of an obesogenic diet.

Delineating effect of corn microRNAs and matrix, ingested as whole food, on gut microbiota in a rodent model.

Dietary microRNAs (miRNAs) are thought to regulate a wide range of biological processes, including the gut microbiota. However, it is difficult to separate specific effect(s) of miRNA from that of the food matrix. This study aims to elucidate the specific effect(s) of dietary corn miRNAs, ingested as a whole food, on the gut microbiota. We developed an autoclave procedure to remove 98% of miRNA from corn. A mouse feeding study was conducted comparing autoclaved corn to nonautoclaved corn and purified corn miRNA. Compared to nonspecific nucleotides and corn devoid of miRNAs, feeding purified corn miRNAs or corn to C57BL/6 mice via gavage or diet supplementation for two weeks lead to a decrease in total bacteria in the cecum. The effect appeared to be due to changes in Firmicutes. Additionally, corn matrix minus miRNA and processing also affected gut bacteria. In silico analysis identified corn miRNAs that aligned to Firmicutes genome sequences lending further support to the interaction between corn miRNAs and this bacterium. These data support interactions between plant food miRNA, as well as matrix, and the gut microbiota exist but complex. However, it provides additional support for mechanism by which bioactive dietary components interact with the gut microbiota.

Javamide-II Inhibits IL-6 without Significant Impact on TNF-alpha and IL-1beta in Macrophage-Like Cells.

The main aim of this study is to find a therapeutic compound to inhibit IL-6, not TNF-alpha and IL-1beta, in macrophage-like cells, because the high-levels of IL-6 production by macrophages are reported to cause unfavorable outcomes under several disease conditions (e.g., autoimmune diseases, and acute viral infections, including COVID-19). In this study, the potential effects of javamide-II on IL-6, IL-1beta and TNF-alpha productions were determined using their ELISA kits in macrophage-like THP-1 cells. Western blots were also performed using the same cells, to determine its effects on signaling pathways (ERK, p38, JNK, c-Fos, ATF-2, c-Jun and NF-κB p65). At concentrations of 0.2-40 µM, javamide-II inhibited IL-6 production significantly in the THP-1 cells (IC50 of 0.8 µM) (P < 0.02). However, javamide-II did not inhibit IL-1beta or TNF-alpha productions much at the same concentrations. In addition, the treatment of javamide-II decreased the phosphorylation of p38 without significant effects on ERK and JNK phosphorylations in the THP-1 cells. Furthermore, the p38 inhibition, followed by the reduction of ATF-2 phosphorylation (not c-Fos, c-Jun or NF-κB p65), led to the suppression of IL-6 mRNA expression in the cells (P < 0.02). The data indicate that javamide-II may be a potent compound to inhibit IL-6 production via suppressing the p38 signal pathway, without significant effects on the productions of TNF-alpha and IL-1beta in macrophage-like THP-1 cells.

Indole-3-Carbinol Inhibits Citrobacter rodentium Infection through Multiple Pathways Including Reduction of Bacterial Adhesion and Enhancement of Cytotoxic T Cell Activity.

Intestinal inflammation is associated with an increased risk of developing colorectal cancer and may result from dysregulated responses to commensal bacteria or exposure to bacterial pathogens. Dietary modulation of intestinal inflammation may protect against development of colon cancer. However, the precise diet-derived components and underlying mechanisms remain elusive. Citrobacter rodentium (Cr) induces acute intestinal inflammation and has been used to study the role of inflammation in the susceptibility to colon cancer. Here we examine the effects of indole-3-carbinol (I3C), a dietary compound with anticarcinogenic properties, on intestinal immune and inflammatory responses to Cr infection and adhesion to colonic cells in vitro. C57BL/6J mice were fed a diet with/without 1 µmol/g I3C and infected with Cr. Compared to infected mice fed with a control diet, consumption of a 1 µmol I3C/g diet significantly reduced fecal excretion of Cr, Cr colonization of the colon, and reduced colon crypt hyperplasia. Furthermore, expression of Cr-induced inflammatory markers such as IL-17A, IL-6, and IL1ß were attenuated in infected mice fed with the I3C diet, compared to mice fed a control diet. The expression of cytotoxic T cell markers CD8 and FasL mRNA were increased in I3C-fed infected mice. In-vitro, I3C inhibited Cr growth and adhesion to Caco-2 cells. I3C alleviates Cr-induced murine colitis through multiple mechanisms including inhibition of Cr growth and adhesion to colonic cells in vitro and enhancement of cytotoxic T cell activity.

Potentiation of IL-4 Signaling by Retinoic Acid in Intestinal Epithelial Cells and Macrophages-Mechanisms and Targets.

We previously demonstrated that IL4, IL13, CLCA1, and CCL26 mRNA were significantly upregulated in the lungs of pigs given a low dose of all trans-retinoic acid (ATRA) and infected with Ascaris suum. We also demonstrated that in vitro ATRA induced a state of partial alternative activation in porcine macrophages (Mφs) and amplified certain aspects of M2a activation induced by IL-4. Given these results, we tested the effect of ATRA on IL-4 responses in two porcine intestinal epithelial cell lines, IPEC1 and IPEC-J2 and observed that ATRA increased mRNA for the IL-4 receptor alpha chain. ATRA also increased IL-4 induced phosphorylation of signal transducer and activator of transcription 6 (STAT6) and mRNA expression of the chloride channel, calcium activated, family member 1 (CLCA1), important for mucus formation, and chemokine (C-C motif) ligand 26 (CCL26), a potent eosinophil chemoattractant. We extended these findings to human Mφ THP-1 cells and showed that ATRA synergistically increased IL-4-induced CCL2, CCL13, and CCL26 mRNA and protein levels. Transglutaminase 2 mRNA, protein, and enzyme activity were synergistically induced in THP-1 cells pretreated with ATRA and then treated with IL-4, thus, ATRA increased signaling in response to IL-4 in porcine epithelial cells and porcine and human Mφs. Given the prevalence of allergic and parasitic diseases worldwide and the close similarities in the porcine and human immune responses, these findings have important implications for the nutritional regulation of allergic inflammation at mucosal surfaces.

Dietary Indole-3-Carbinol Alleviated Spleen Enlargement, Enhanced IgG Response in C3H/HeN Mice Infected with Citrobacter rodentium.

Enteropathogenic and enterohemorrhagic Escherichia coli are important enteric pathogens that induce hemorrhagic colitis or even fatal hemolytic uremic syndrome. Emerging evidence shows that some bio-actives derived from fruits and vegetables may serve as alternatives to antibiotics for overcoming multidrug resistant E. coli infections. In this study, the Citrobacter rodentium (Cr) infection model was utilized to mimic E. coli-induced acute intestinal inflammation, and the effects of a cruciferous vegetable-derived cancer protective compound, indole-3-carbinol (I3C), on the immune responses of Cr-susceptible C3H/HeN mice were investigated. Dietary I3C significantly inhibited the loss of body weight and the increase in spleen size in Cr infected mice. In addition, I3C treatment reduced the inflammatory response to Cr infection by maintaining anti-inflammatory cytokine IL-22 mRNA levels while reducing expression of other pro-inflammatory cytokines including IL17A, IL6, IL1ß, TNF-α, and IFN-γ. Moreover, the serum cytokine levels of IL17, TNF-α, IL12p70, and G-CSF also were down-regulated by I3C in Cr-infected mice. Additionally, dietary I3C specifically enhanced the Cr-specific IgG response to Cr infection. In general, dietary I3C reduced the Cr-induced pro-inflammatory response in susceptible C3H/HeN mice and alleviated the physiological changes and tissue damage induced by Cr infection but not Cr colonization.

Mechanistic insights into the attenuation of intestinal inflammation and modulation of the gut microbiome by krill oil using in vitro and in vivo models.

BACKGROUND: The anti-inflammatory property of ω-3 polyunsaturated fatty acids (PUFA) has been exploited in the management of inflammatory bowel disease (IBD) with promising results. However, it remains unclear if PUFA play a significant role in the resolution of inflammation and promotion of mucosal healing. Krill oil (KO) is a natural product rich in PUFA and the potent antioxidant, astaxanthin. In this study, we attempted to understand the mechanisms through which KO modulates the gut microbiome and metabolome using in vitro and in vivo colitis models and a multi-omics based approach. RESULTS: KO significantly decreased LPS-induced IL1ß and TNFα expression in human macrophages in vitro in a dose-dependent manner by regulating a broad spectrum of signaling pathways, including NF-κB and NOD-like receptor signaling, and displayed a synergistic effect with COX2 and IKK2 inhibitors in attenuating inflammatory pathways. Moreover, KO was involved in the resolution of inflammation by promoting M2 polarization and enhancing macrophage-mediated intracellular bacterial killing. Parasite-dependent intestinal mucosal damage and microbial dysbiosis induced by Trichuris suis infection in pigs were partially restored by feeding KO. KO supplementation reduced the abundance of Rickettsiales and several species of Lactobacillus, which were among the important features identified by random forests analysis contributing to classification accuracy for KO supplementation. Several microbial signatures with strong predictive power for the status of both infection and supplementation were identified. The inhibitory effect of KO on histidine metabolism was identified using untargeted metabolomics. KO supplementation reduced several key metabolites related to histamine metabolism by suppressing the expression of a gene encoding L-histidine decarboxylase in the colon mucosa and reducing histamine biosynthesis of microbial origin. Moreover, the pro-resolving properties of KO were validated using a Citrobacter rodentium-induced Th1-dependent colitis murine model. Further, microbial signatures with high prediction accuracy for colitis-related pathophysiological traits were identified in mice. CONCLUSION: The findings from this study provided a mechanistic basis for optimizing microbiome-inspired alternative therapeutics in the management of IBD. The microbial signatures identified, particularly those with strong predictive accuracy for colitis phenotypes, will facilitate the development of biomarkers associated with appropriate dietary intervention to manage intestinal inflammation. Video abstract.