Protection of intestinal occludin tight junction protein by dietary gangliosides in lipopolysaccharide-induced acute inflammation

Dietary milk polar lipids modulate gut barrier integrity and lipid metabolism in C57BL/6J mice during systemic inflammation induced by Escherichia coli lipopolysaccharide

The focus of this work is the role milk polar lipids play in affecting gut permeability, systemic inflammation, and lipid metabolism during acute and chronic inflammation induced by a single subcutaneous injection of lipopolysaccharide. Three groups of C57BL/6J mice were fed: modified AIN-93G diet with moderate level of fat (CO); CO with milk gangliosides (GG); CO with milk phospholipids (MPL). The MPL did not prevent a gut permeability increase upon LPS stress but increased the expression of tight junction proteins zonula occludens-1 and occludin in colon mucosa. The GG prevented the gut permeability increase upon LPS stress. The MPL decreased absolute and relative liver mass and decreased hepatic gene expression of acetyl-CoA carboxylase 2 and 3-hydroxy-3-methylglutaryl-CoA reductase. The GG increased hepatic gene expression of acetyl-CoA acyltransferase 2. In conclusion, milk GG protected the intestinal barrier integrity but had little effect on systemic inflammation and lipid metabolism; milk MPL, conversely, had complex effects on gut permeability, did not affect systemic inflammation, and had beneficial effect on hepatic lipid metabolism.

Synthesis and antibacterial activity of FST and its effects on inflammatory response and intestinal barrier function in mice infected with Escherichia coli O78

Pathogenic Escherichia coli (E. coli) can cause intestinal diseases in humans and livestock, damage the intestinal barrier, increase systemic inflammation, and seriously threaten human health and the development of animal husbandry. In this study, we designed and synthesized a novel conjugate florfenicol sulfathiazole (FST) based on drug combination principles, and investigated its antibacterial activity in vitro and its protective effect on inflammatory response and intestinal barrier function in E. coli O78-infected mice in vivo. The results showed that FST had superior antibacterial properties and minimal cytotoxicity compared with its prodrugs as florfenicol and sulfathiazole. FST protected mice from lethal E. coli infection, reduced clinical signs of inflammation, reduced weight loss, alleviated intestinal structural damage. FST decreased the expression of inflammatory cytokines IL-1β, IL-6, TNF-α, and increased the expression of claudin-1, Occludin, and ZO-1 in the jejunum, improved the intestinal barrier function, and promoted the absorption of nutrients. FST also inhibited the expression of TLR4, MyD88, p-p65, and p-p38 in the jejunum. The study may lay the foundation for the development of FST as new drugs for intestinal inflammation and injury in enteric pathogen infection.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Sphingolipids: From structural components to signaling hubs

In late November 2019, Prof. Lina M. Obeid passed away from cancer, a disease she spent her life researching and studying its intricate molecular underpinnings. Along with her husband, Prof. Yusuf A. Hannun, Obeid laid down the foundations of sphingolipid biochemistry and oversaw its remarkable evolution over the years. Lipids are a class of macromolecules that are primarily associated with cellular architecture. In fact, lipids constitute the perimeter of the cell in such a way that without them, there cannot be cells. Hence, much of the early research on lipids identified the function of this class of biological molecules as merely structural. Nevertheless, unlike proteins, carbohydrates, and nucleic acids, lipids are elaborately diverse as they are not made up of monomers in polymeric forms. This diversity in structure is clearly mirrored by functional pleiotropy. In this chapter, we focus on a major subset of lipids, sphingolipids, and explore their historic rise from merely inert structural components of plasma membranes to lively and necessary signaling molecules that transmit various signals and control many cellular processes. We will emphasize the works of Lina Obeid since she was an integral pillar of the sphingolipid research world.

Rabdosia serra alleviates dextran sulfate sodium salt-induced colitis in mice through anti-inflammation, regulating Th17/Treg balance, maintaining intestinal barrier integrity, and modulating gut microbiota

Rabdosia serra (R. serra), an important component of Chinese herbal tea, has traditionally been used to treat hepatitis, jaundice, cholecystitis, and colitis. However, the chemical composition of R. serra and its effect against colitis remain unclear. In this study, the chemical composition of the water extract of R. serra was analyzed using ultra performance liquid chromatography coupled with a hybrid linear ion trap quadrupole-orbitrap mass spectrometer (UPLC-LTQ-Orbitrap-MS). A total of 46 compounds, comprising ent-kaurane diterpenoids, flavonoids, phenolic acids, and steroids, were identified in the water extract of R. serra, and the extract could significantly alleviate dextran sulfate sodium salt-induced colitis by improving colon length, upregulating anti-inflammatory factors, downregulating proinflammatory factors, and restoring the balance of T helper 17/T regulatory cells. R. serra also preserved intestinal barrier function by increasing the level of tight junction proteins (zonula occludens 1 and occludin) in mouse colonic tissue. In addition, R. serra modulated the gut microbiota composition by increasing bacterial richness and diversity, increasing the abundance of beneficial bacteria (Muribaculaceae, Bacteroides, Lactobacillus, and Prevotellaceae_UCG-001), and decreasing the abundance of pathogenic bacteria (Turicibacter, Eubacterium_fissicatena_group, and Eubacterium_xylanophilum_group). Gut microbiota depletion by antibiotics further confirmed that R. serra alleviated colitis in a microbiota-dependent manner. Overall, our findings provide chemical and biological evidence for the potential application of R. serra in the management of colitis.

Dietary Glutamine Supplementation Alleviated Inflammation Responses and Improved Intestinal Mucosa Barrier of LPS-Challenged Broilers

Simple Summary

In commercial intense industry, birds have to undergo a series of physical, social and microbial stress. LPS, a structural substance of gram-negative bacterial membrane and an effective immune stimulator for human and animal immune system, can impair growth performance, elevate the production of inflammatory cytokines and destroy the morphology of broilers’ small intestine. Moreover, LPS challenge also can reduce the expression levels of tight junction proteins and ruin the integrity of mucosal barrier of broilers. However, glutamine is considered to be conditionally essential for gut homeostasis and barrier function and maybe a useful strategy to attenuate immunological stress and improve intestine function in response to stressful conditions. Our study showed that 1% Gln supplementation improved the growth performance, alleviated the inflammatory responses and ameliorated the intestinal permeability and the integrity of intestinal mucosa barrier of LPS-challenged broilers.

Abstract

The present study was conducted to investigate the effects of glutamine (Gln) supplementation on intestinal inflammatory reaction and mucosa barrier of broilers administrated with lipopolysaccharide (LPS) stimuli. A total of 120 1-d-old male broilers were randomly divided into four treatments in a 2 × 2 experimental arrangement, containing immune challenge (injected with LPS in a dose of 0 or 500 μg/kg of body weight) and dietary treatments (supplemented with 1.22% alanine or 1% Gln). The results showed that growth performance of broilers intra-abdominally injected with LPS was impaired, and Gln administration alleviated the adverse effects on growth performance induced by LPS challenge. Furthermore, Gln supplementation reduced the increased concentration of circulating tumor necrosis factor-α, interleukin-6 and interleukin-1β induced by LPS challenge. Meanwhile, D-lactic acid and diamine oxidase concentration in plasma were also decreased by Gln supplementation. In addition, the shorter villus height, deeper crypt depth and the lower ratio of villus height to crypt depth of duodenum, jejunum and ileum induced by LPS stimulation were reversed by Gln supplementation. Gln administration beneficially increased LPS-induced reduction in the expression of intestine tight junction proteins such as zonula occludens protein 1 (ZO-1), claudin-1 and occludin except for the ZO-1 in duodenum and occludin in ileum. Moreover, Gln supplementation downregulated the mRNA expression of toll-like receptor 4, focal adhesion kinase, myeloid differentiation factor 88 and IL-1R-associated kinase 4 in TLR4/FAK/MyD88 signaling pathway. Therefore, it can be concluded that Gln administration could attenuate LPS-induced inflammatory responses and improve intestinal barrier damage of LPS-challenged broilers.

Bacterial-Induced Blood Pressure Reduction: Mechanisms for the Treatment of Hypertension via the Gut

Hypertension is a major risk factor for the development of cardiovascular disease. As more research into the gut microbiome emerges, we are finding increasing evidence to support that these microbes may have significant positive and negative effects on blood pressure and associated disorders. The bacterial-derived metabolites that are produced in the gut are capable of widespread effects to several tissue types and organs in the body. It is clear that the extensive metabolic function that is lost with gut dysbiosis is unlikely to be replenished with a single metabolite or bacterial strain. Instead, combinations of bacteria and concomitant therapies will provide a more well-rounded solution to manage hypertension. The bioactive molecules that are recognized in this review will inform on ideal characteristics of candidate bacteria and provide direction for future research on the gut microbiome in hypertension.

Dioscin prevents DSS-induced colitis in mice with enhancing intestinal barrier function and reducing colon inflammation

Dioscin is a natural steroid saponin derived from plants of the genus Dioscoreaceae. Previous studies have proved its effects of antibacterial, anti-inflammatory and hypolipidemic. In this study, our aim was to explore the protective effect and preliminary mechanism of Dioscin on dextran sulfate sodium (DSS)-induced colitis in mice. The results showed that Dioscin reduced DSS-induced disease activity index (DAI) increase, colon length shortening and colon pathological damage. In addition, Dioscin reduced excessive inflammation by reversing the cytokines levels, reducing intestinal macrophage infiltration and promoting macrophage polarization to M2 phenotype. At the same time, Dioscin maintained the intestinal barrier function by increasing the expression of zonula occludens-1 (ZO-1), occludin and mucin (Muc)-2. Moreover, Dioscin inhibited NF-κB, MAPK signaling and nucleotide oligomerization domain-like receptor family pyrin domain ontaining 3(NLRP3) inflammasome pathway in DSS-induced colitis. These results suggest that Dioscin is a competent candidate for ulcerative colitis (UC) therapy in the future.

Characterization of Gangliosides in Three Sea Urchin Species by HILIC-ESI-MS/MS

Sea urchin gangliosides (SU-GLSs) are well acknowledged for their nerve regeneration activity and neuroprotective property. The present study sought to characterize and semi-quantitate different SU-GLS subclasses in three sea urchin species, including Strongylocentrotus nudus, Hemicentrotus pulcherrimus, and Glyptocidaris crenularis. A total of 14 SU-GLS subclasses were identified by a hydrophilic interaction liquid chromatography-Q-Exactive tandem mass spectrometry method. Three sialic acid (Sia) structures, including Neu5Ac, Neu5Gc, and KDN, were identified in SU-GLSs, of which Neu5Ac and Neu5Gc had their corresponding sulfated forms. The linkage among Sias was determined to be 2-8. Additionally, KDN2-6Glc1-1Cer, KDN2-8Neu5Gc2-6Glc1-1Cer, and KDN2-8Neu5Gc2-8Neu5Gc2-6Glc-1Cer were speculated to be novel SU-GLS structures. Furthermore, the total SU-GLS content was 2.0-7.3 mg/g in the three sea urchin species. These results will provide useful data for developing a SU-GLS database of aquatic products. Besides, this study will provide a theoretical basis to explore the nutritional values of seafood products further.

Ganglioside Alters Phospholipase Trafficking, Inhibits NF-κB Assembly, and Protects Tight Junction Integrity

Background and Aims: Dietary gangliosides are present in human milk and consumed in low amounts from organ meats. Clinical and animal studies indicate that dietary gangliosides attenuate signaling processes that are a hallmark of inflammatory bowel disease (IBD). Gangliosides decrease pro-inflammatory markers, improve intestinal permeability, and reduce symptoms characteristic in patients with IBD. The objective of this study was to examine mechanisms by which dietary gangliosides exert beneficial effects on intestinal health. Methods: Studies were conducted in vitro using CaCo-2 intestinal epithelial cells. Gangliosides were extracted from milk powder and incubated with differentiated CaCo-2 cells after exposure to pro-inflammatory stimuli. Gut barrier integrity was assessed by electron microscopy, epithelial barrier function was examined by measuring transepithelial electric resistance, and content of HBD-2, IL-23, NF-κB, and sPLA₂ was assessed by ELISA. Results: Ganglioside attenuated the decrease in integrity of tight junctions induced by pro-inflammatory stimuli and improved epithelial barrier function (P < 0.05). Ganglioside decreased the basolateral secretion of sPLA₂ (P ≤ 0.05), lowered HBD-2 and IL-23 levels (P ≤ 0.05), and inhibited NF-κB activation (P ≤ 0.05). Conclusions: In summary, the present study indicates that ganglioside GD3 improves intestinal integrity by altering sPLA₂ trafficking, and the production of pro-inflammatory mediators is mitigated by decreasing assembly of the NF-κB complex. Dietary gangliosides may have promising potential beneficial effects in IBD as decreased inflammatory signaling, improved intestinal integrity, and maintenance of epithelial barrier function have been demonstrated in vitro.

Dietary Sphingolipids Contribute to Health via Intestinal Maintenance

As sphingolipids are constituents of the cell and vacuole membranes of eukaryotic cells, they are a critical component acquired from our daily diets. In the present review, we highlight the knowledge regarding how dietary sphingolipids affect our health, particularly our intestinal health. Animal- and plant-derived foods contain, respectively, sphingomyelin (SM) and glucosylceramide (GlcCer) as their representative sphingolipids, and the sphingoid base as a specific structure of sphingolipids also differs depending upon the source and class. For example, sphingosine is predominant among animal sphingolipids, and tri-hydroxy bases are present in free ceramide (Cer) from plants and fungi. Dietary sphingolipids exhibit low absorption ratios; however, they possess various functions. GlcCer facilitates improvements in intestinal impairments, lipid metabolisms, and skin disorders, and SM can exert both similar and different effects compared to those elicited by GlcCer. We discuss the digestion, absorption, metabolism, and function of sphingolipids while focused on the structure. Additionally, we also review old and new classes in the context of current advancements in analytical instruments.

Early life administration of milk fat globule membrane promoted SCFA-producing bacteria colonization, intestinal barriers and growth performance of neonatal piglets

Milk fat globule membrane (MFGM) possesses various nutritional and biological benefits for mammals, whereas its effects on neonatal gut microbiota and barrier integrity remained unclear. This study investigated the effects of MFGM administration on microbial compositions and intestinal barrier functions of neonatal piglets. Sixteen newborn piglets were randomly allocated into a CON group or MFGM group, orally administered with saline or MFGM solution (1 g/kg body weight) respectively during the first postnatal week, and all piglets were breastfed during the whole neonatal period. The present study found that the MFGM oral administration during the first postnatal week increased the plasma immunoglobulin (Ig) G level, body weight and average daily gain of piglets (P < 0.05) on 21 d. Additionally, MFGM administration enriched fecal SCFA-producing bacteria (Ruminococ aceae_UCG-002, Ruminococ aceae_UCG-010, Ruminococ aceae_UCG-004, Ruminococ aceae_UCG-014 and [Ruminococcus]_gauvrearuii_group), SCFA concentrations (acetate, propionate and butyrate; P < 0.05) and their receptor (G-protein coupled receptor 41, GPR41). Furthermore, MFGM administration promoted intestinal villus morphology (P < 0.05) and barrier functions by upregulating genes of tight junctions (E-cadherin, claudin-1, occludin and zonula occludin 1 [ZO-1]), mucins (mucin-13 and mucin-20) and interleukin (IL)-22 (P < 0.05). Positive correlation was found between the beneficial microbes and SCFA levels pairwise with the intestinal barrier genes (P < 0.05). In conclusion, orally administrating MFGM during the first postnatal week stimulated SCFA-producing bacteria colonization and SCFA generation, enhanced intestinal barrier functions and consequently improved growth performance of neonatal piglets on 21 d. Our findings will provide new insights about MFGM intervention for microbial colonization and intestinal development of neonates during their early life.

Gly-Pro-Ala peptide and FGSHF3 exert protective effects in DON-induced toxicity and intestinal damage via decreasing oxidative stress

Deoxynivalenol (DON), a common mycotoxin, usually induces oxidative stress and intestinal injury of humans and animals. This study aims to investigate the protective effect of Gly-Pro-Ala (GPA) peptide, isolated from fish skin gelatin hydrolysate fraction 3 (FGSHF3), on alleviating the toxicity and oxidative stress induced by DON in the mice and IPEC-J2 cells. DON treatment decreases average daily gain and feeds intake, which causes enlargement of the liver and spleen. FGSHF3 (200 mg/kg) and GPA (200 mg/kg) treatment significantly increase average daily gain and inhibits enlargement of the liver and spleen. Furthermore, FGSHF3 and GPA treatment significantly alleviates intestinal injury and maintains tight junction in mice and IPEC-J2 cells. FGSHF3 and GPA treatment significantly inhibits ROS and MDA production and enhances antioxidant enzyme activity, such as CAT, SOD-1, GCLM, GCLC, and GSH-PX. Furthermore, FGSHF3 and GPA treatment promote Nrf2 migration from the cytoplasm to the nucleus, resulting in exerting antioxidant effects. And its effects are abolished after Nrf2 is knockdown by siRNA. Overall, our results suggest GPA peptide may be a promising candidate for the alleviation of DON-induced toxicity in humans and animals.

Lipid metabolism dysregulation in diabetic retinopathy

Lipid metabolic abnormalities have emerged as potential risk factors for the development and progression of diabetic complications, including diabetic retinopathy (DR). This review article provides an overview of the results of clinical trials evaluating the potential benefits of lipid-lowering drugs, such as fibrates, omega-3 fatty acids, and statins, for the prevention and treatment of DR. Although several clinical trials demonstrated that treatment with fibrates leads to improvement of DR, there is a dissociation between the protective effects of fibrates in the retina, and the intended blood lipid classes, including plasma triglycerides, total cholesterol, or HDL:LDL cholesterol ratio. Guided by these findings, plasma lipid and lipoprotein-independent mechanisms are addressed based on clinical, cell culture, and animal model studies. Potential retinal-specific effects of fatty acid oxidation products, cholesterol, and ceramide, as well as lipid-independent effects of PPAR alpha activation, are summarized based on the current literature. Overall, this review highlights promising potential of lipid-based treatment strategies further enhanced by the new knowledge of intraretinal lipids and lipoproteins in DR.

Influence of Plant Bioactive Compounds on Intestinal Epithelial Barrier in Poultry

Natural plant bioactive compounds (PBC) have recently been explored as feed additives to improve productivity, health and welfare of poultry following ban or restriction of in-feed antibiotic use. Depending upon the types of PBC, they possess antimicrobial, digestive enzyme secretion stimulation, antioxidant and many pharmacological properties, which are responsible for beneficial effects in poultry production. Moreover, they may also improve the intestinal barrier function and nutrient transport. In this review, the effects of different PBC on the barrier function, permeability of intestinal epithelia and their mechanism of actions are discussed, focusing on poultry feeding. Dietary PBC may regulate intestinal barrier function through several molecular mechanisms by interacting with different metabolic cascades and cellular transcription signals, which may then modulate expressions of genes and their proteins in the tight junction (e.g., claudins, occludin and junctional adhesion molecules), adherens junction (e.g., E-cadherin), other intercellular junctional proteins (e.g., zonula occludens and catenins), and regulatory proteins (e.g., kinases). Interactive effects of PBC on immunomodulation via expressions of several cytokines, chemokines, complement components, pattern recognition receptors and their transcription factors and cellular immune system, and alteration of mucin gene expressions and goblet cell abundances in the intestine may change barrier functions. The effects of PBC are not consistent among the studies depending upon the type and dose of PBC, physiological conditions and parts of the intestine in chickens. An effective concentration in diets and specific molecular mechanisms of PBC need to be elucidated to understand intestinal barrier functionality in a better way in poultry feeding.

A highly efficient hybrid peptide ameliorates intestinal inflammation and mucosal barrier damage by neutralizing lipopolysaccharides and antagonizing the lipopolysaccharide-receptor interaction

Intestinal inflammatory disorders, such as inflammatory bowel disease, are major contributors to mortality and morbidity in humans and animals worldwide. While some native peptides have great potential as therapeutic agents against intestinal inflammation, potential cytotoxicity, anti-inciting action, and suppression of anti-inflammatory activity may limit their development as anti-inflammatory agents. Peptide hybridization is an effective approach for the design and engineering of novel functional peptides because hybrid peptides combine the advantages and benefits of various native peptides. In the present study, a novel hybrid anti-inflammatory peptide that combines the active center of Cecropin A (C) and the core functional region of LL-37 (L) was designed [C-L peptide; C (1-8)-L (17-30)] through in silico analysis to reduce cytotoxicity and improve the anti-inflammatory activity of the parental peptides. The resulting C-L peptide exhibited lower cytotoxicity than either C or L peptides alone. C-L also exerted a protective effect against lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 macrophages and in the intestines of a mouse model. The hybrid peptide exhibited increased anti-inflammatory activity compared to the parental peptides. C-L plays a role in protecting intestinal tissue from damage, LPS-induced weight loss, and leukocyte infiltration. In addition, C-L reduces the expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and interferon-gamma (IFN-γ), as well as reduces cell apoptosis. It also reduced mucosal barrier damage caused by LPS. The anti-inflammatory effects of the hybrid peptide were mainly attributed to its LPS-neutralizing activity and antagonizing the activation of LPS-induced Toll-like receptor 4-myeloid differentiation factor 2 (TLR4/MD2). The peptide also affected the TLR4-(nuclear factor κB) signaling pathway, modulating the inflammatory response upon LPS stimulation. Collectively, these findings suggest that the newly designed peptide, C-L, could be developed into a novel anti-inflammatory agent for animals or humans.

Role of Microbiota in Pathogenesis and Management of Viral Hepatitis

Hepatitis is a condition that can be self-limiting or can progress to fibrosis (scarring), cirrhosis, or liver cancer. These days, gut microbiota becomes an important part of our immune system, which is important for disease progression or recovery. Translocation of gut microbial and metabolic products causes intestinal inflammation by modulating immune cells leading to impairment of the primary barrier. But there are limited studies discussing pathogenesis and management of hepatitis with gut microbiota. In this review, we have discussed the role of gut microbiota in pathogenesis and management of various hepatitis, especially hepatitis B and C. We have discussed the role of bacterial products, LPS-TLR4 pathway, and unmethylated CpG DNA, which ultimately affects downstream NF-kB signaling in hepatitis. Finally, we have discussed the role of fecal microbiota transplantation in the management of hepatitis.

Prevention of Necrotizing Enterocolitis through Milk Polar Lipids Reducing Intestinal Epithelial Apoptosis

Neonatal necrotizing enterocolitis (NEC) is a common and devastating disease. The objective of this research was to investigate the protective mechanisms of milk polar lipids (MPLs) on the attenuation of lipopolysaccharides (LPS)-induced intestinal inflammation and apoptosis. MPLs were extracted from buttermilk and analyzed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A neonatal NEC rat model was used to investigate the effects of MPLs on NEC and its underlying mechanisms. Hematoxylin-eosin (H&E) staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) assay were used to observe intestinal morphological changes and intestinal epithelial cell apoptosis, which showed that MPLs could reduce NEC symptoms and intestinal apoptosis. The expressions of IL-6, IL-8, and TNF-α in the MPL group was significantly downregulated (P < 0.05), and the expression levels of IL-10 were significantly upregulated (P < 0.05). At the same time, MPLs also significantly reduced (P < 0.05) activation of the LPS-induced TLR4/NF-κB signaling pathway. Furthermore, MPLs inhibit apoptosis by reducing the expressions of Bax, caspase-9, and caspase-3 and by increasing the expression of Bcl-2. In conclusion, MPLs could reduce NEC symptoms in mice by inhibiting cell inflammation and protecting against intestinal apoptosis.

A Novel Cecropin-LL37 Hybrid Peptide Protects Mice Against EHEC Infection-Mediated Changes in Gut Microbiota, Intestinal Inflammation, and Impairment of Mucosal Barrier Functions

Intestinal inflammation can cause impaired epithelial barrier function and disrupt immune homeostasis, which increases the risks of developing many highly fatal diseases. Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes intestinal infections worldwide and is a major pathogen that induces intestinal inflammation. Various antibacterial peptides have been described as having the potential to suppress and treat pathogen-induced intestinal inflammation. Cecropin A (1–8)-LL37 (17–30) (C-L), a novel hybrid peptide designed in our laboratory that combines the active center of C with the core functional region of L, shows superior antibacterial properties and minimized cytotoxicity compared to its parental peptides. Herein, to examine whether C-L could inhibit pathogen-induced intestinal inflammation, we investigated the anti-inflammatory effects of C-L in EHEC O157:H7-infected mice. C-L treatment improved the microbiota composition and microbial community balance in mouse intestines. The hybrid peptide exhibited improved anti-inflammatory effects than did the antibiotic, enrofloxacin. Hybrid peptide treated infected mice demonstrated reduced clinical signs of inflammation, reduced weight loss, reduced expression of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interferon-gamma (IFN-γ)], reduced apoptosis, and reduced markers of jejunal epithelial barrier function. The peptide also affected the MyD88–nuclear factor κB signaling pathway, thereby modulating inflammatory responses upon EHEC stimulation. Collectively, these findings suggest that the novel hybrid peptide C-L could be developed into a new anti-inflammatory agent for use in animals or humans.

Dietary pterostilbene supplementation attenuates intestinal damage and immunological stress of broiler chickens challenged with lipopolysaccharide

The present study explored the potential effect of pterostilbene as a prophylactic treatment on the lipopolysaccharide (LPS)-induced intestinal injury of broiler chickens by monitoring changes in mucosal injury indicators, redox status, and inflammatory responses. In total, 192 one-day-old male Ross 308 broiler chicks were randomly divided into four groups. This trial consisted of a 2 × 2 factorial design with a diet factor (supplemented with 0 or 400 mg/kg pterostilbene from 1 to 22 d of age) and a stress factor (intraperitoneally injected with saline or LPS at 5.0 mg/kg BW at 21 da of age). The results showed that LPS challenge induced a decrease in BW gain (P < 0.001) of broilers during a 24-h period postinjection; however, this decrease was prevented by pterostilbene supplementation (P = 0.031). Administration of LPS impaired the intestinal integrity of broilers, as indicated by increased plasma diamine oxidase (DAO) activity (P = 0.014) and d-lactate content (P < 0.001), reduced jejunal villus height (VH; P < 0.001) and the ratio of VH to crypt depth (VH:CD; P < 0.001), as well as a decreased mRNA level of jejunal tight junction protein 1 (ZO-1; P = 0.002). In contrast, pterostilbene treatment increased VH:CD (P = 0.018) and upregulated the mRNA levels of ZO-1 (P = 0.031) and occludin (P = 0.024) in the jejunum. Consistently, pterostilbene counteracted the LPS-induced increased DAO activity (P = 0.011) in the plasma. In addition, the LPS-challenged broilers exhibited increases in nuclear accumulation of nuclear factor kappa B (NF-κB) p65 (P < 0.001), the protein content of tumor necrosis factor α (P = 0.033), and the mRNA abundance of IL-1β (P = 0.042) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3; P = 0.019). In contrast, pterostilbene inhibited the nuclear translocation of NF-κB p65 (P = 0.039) and suppressed the mRNA expression of IL-1β (P = 0.003) and NLRP3 (P = 0.049) in the jejunum. Moreover, pterostilbene administration induced a greater amount of reduced glutathione (P = 0.017) but a lower content of malondialdehyde (P = 0.023) in the jejunum of broilers compared with those received a basal diet. Overall, the current study indicates that dietary supplementation with pterostilbene may play a beneficial role in alleviating the intestinal damage of broiler chicks under the conditions of immunological stress.

FSGHF3 and peptides, prepared from fish skin gelatin, exert a protective effect on DSS-induced colitis via the Nrf2 pathway

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disease affecting the colon, and its incidence is rising worldwide.

The Abilities of Salidroside on Ameliorating Inflammation, Skewing the Imbalanced Nucleotide Oligomerization Domain-Like Receptor Family Pyrin Domain Containing 3/Autophagy, and Maintaining Intestinal Barrier Are Profitable in Colitis

Salidroside (Sal), as a major glycoside extracted from Rhodiola rosea L., has exhibited its mighty anti-aging, anti-oxidant, anti-cancer, anti-inflammation, and neuroprotective effects in many diseases. Recently, it has showed its protective effect in colitis mice by activating the SIRT1/FoxOs pathway. Whereas, it is not known whether Sal has other protective mechanisms on dextran sulfate sodium (DSS)-induced colitis in mice. In this study, we investigated the protective effects and mechanisms of Sal on DSS-induced colitis in mice. The results demonstrated Sal was a competent candidate in the treatment of ulcerative colitis (UC). Sal remitted DSS-induced disease activity index (DAI), colon length shortening, and colonic pathological damage. Simultaneously, Sal alleviated excessive inflammation by reversing the IL-1β, TNF-α, and IL-10 protein levels in DSS-treated mice. Western blot analysis revealed that Sal inhibited p65 and p38 activation together with peroxisome proliferator-activated receptor (PPARγ) up-regulation. In addition, Sal skewed the imbalanced activation of nucleotide oligomerization domain-like receptor family pyrin domain containing 3 inflammasome and autophagy contributing to colitis recovery. The damaged intestinal barrier induced by DSS was also alleviated along with plasma lipopolysaccharides (LPS) reduction after Sal treatment. In vitro, Sal showed PPARγ-dependent anti-inflammatory effect in LPS-stimulated RAW264.7 cells. In summary, our results demonstrated that Sal might be an effective factor for UC treatment and its pharmacological value deserved further development.

Dietary Polar Lipids and Cognitive Development: A Narrative Review

Polar lipids are amphiphilic lipids with a hydrophilic head and a hydrophobic tail. Polar lipids mainly include phospholipids and sphingolipids. They are structural components of neural tissues, with the peak rate of accretion overlapping with neurodevelopmental milestones. The critical role of polar lipids in cognitive development is thought to be mediated through the regulation of signal transduction, myelination, and synaptic plasticity. Animal products (egg, meat, and dairy) are the major dietary sources of polar lipids for children and adults, whereas human milk and infant formula provide polar lipids to infants. Due to the differences observed in both concentration and proportion of polar lipids in human milk, the estimated daily intake in infants encompasses a wide range. In addition, health authorities define neither intake recommendations nor guidelines for polar lipid intake. However, adequate intake is defined for 2 nutrients that are elements of these polar lipids, namely choline and DHA. To date, limited studies exist on the brain bioavailability of dietary polar lipids via either placental transfer or the blood-brain barrier. Nevertheless, due to their role in pre- and postnatal development of the brain, there is a growing interest for the use of gangliosides, which are sphingolipids, as a dietary supplement for pregnant/lactating mothers or infants. In line with this, supplementing gangliosides and phospholipids in wild-type animals and healthy infants does suggest some positive effects on cognitive performance. Whether there is indeed added benefit of supplementing polar lipids in pregnant/lactating mothers or infants requires more clinical research. In this article, we report findings of a review of the state-of-the-art evidence on polar lipid supplementation and cognitive development. Dietary sources, recommended intake, and brain bioavailability of polar lipids are also discussed.

Development of Salmonellosis as Affected by Bioactive Food Compounds

Infections caused by Salmonella serovars are the leading cause of foodborne hospitalizations and deaths in Americans, extensively prevalent worldwide, and pose a considerable financial burden on public health infrastructure and private manufacturing. While a comprehensive review is lacking for delineating the role of dietary components on prevention of Salmonellosis, evidence for the role of diet for preventing the infection and management of Salmonellosis symptoms is increasing. The current study is an evaluation of preclinical and clinical studies and their underlying mechanisms to elaborate the efficacy of bioactive dietary components for augmenting the prevention of Salmonella infection. Studies investigating dietary components such as fibers, fatty acids, amino acids, vitamins, minerals, phenolic compounds, and probiotics exhibited efficacy of dietary compounds against Salmonellosis through manipulation of host bile acids, mucin, epithelial barrier, innate and adaptive immunity and gut microbiota as well as impacting the cellular signaling cascades of the pathogen. Pre-clinical studies investigating synergism and/or antagonistic activities of various bioactive compounds, additional randomized clinical trials, if not curtailed by lack of equipoise and ethical concerns, and well-planned epidemiological studies could augment the development of a validated and evidence-based guideline for mitigating the public health burden of human Salmonellosis through dietary compounds.

Design and Development of a Novel Peptide for Treating Intestinal Inflammation

Intestinal inflammatory disorders, such as inflammatory bowel disease (IBD), are associated with increased pro-inflammatory cytokine secretion in the intestines. Furthermore, intestinal inflammation increases the risk of enteric cancer, which is a common malignancy globally. Native anti-inflammatory peptides are a class of anti-inflammatory agents that could be used in the treatment of several intestinal inflammation conditions. However, potential cytotoxicity, and poor anti-inflammatory activity have prevented their development as anti-inflammatory agents. Therefore, in this study, we designed and developed a novel hybrid peptide for the treatment of intestinal inflammation. Eight hybrid peptides were designed by combining the active centers of antimicrobial peptides, including LL-37 (13-36), YW12D, innate defense regulator 1, and cathelicidin 2 (1-13) with thymopentin or the active center of thymosin alpha 1 (Tα1) (17-24). The hybrid peptide, LL-37-Tα1 (LTA), had improved anti-inflammatory activity with minimal cytotoxicity. LTA was screened by molecule docking and in vitro experiments. Likewise, its anti-inflammatory effects and mechanisms were also evaluated using a lipopolysaccharide (LPS)-induced intestinal inflammation murine model. The results showed that LTA prevented LPS-induced impairment in the jejunum epithelium tissues and infiltration of leukocytes, which are both histological markers of inflammation. Additionally, LTA decreased the levels of tumor necrosis factor-alpha, interferon-gamma, interleukin-6, and interleukin-1β. LTA increased the expression of zonula occludens-1 and occludin, and reduced permeability and apoptosis in the jejunum of LPS-treated mice. Additionally, its anti-inflammatory effect is associated with neutralizing LPS, binding to the Toll-like receptor 4-myeloid differentiation factor 2 (TLR4/MD-2) complex, and modulating the nuclear factor-kappa B signal transduction pathway. The findings of this study suggest that LTA may be an effective therapeutic agent in the treatment of intestinal inflammation.

Cathelicidin- derived PR39 protects enterohemorrhagic Escherichia coli O157:H7 challenged mice by improving epithelial function and balancing the microbiota in the intestine

The zoonotic enterohaemorrhagic Escherichia coli (EHEC) O157:H7 can disrupt intestinal epithelial barrier function and in turn leading to serious intestinal and systemic disease. PR39 could effectively inhibit the growth of Gram-negative bacteria, but there is little knowledge of its effects on intestinal barrier function and the microbiota in E. coli-challenged mice. In this study, an intestinal disease caused by EHEC O157:H7 was established, to analyze the effect of PR39 on EHEC O157:H7 induced intestinal epithelial barrier injury and disorder. Interestingly, PR39 attenuated EHEC O157:H7-induced systemic symptoms and significantly decreased mortality and the degree of E. coli shedding in faeces. Furthermore, the infiltration index of macrophages and neutrophils in intestine of the PR39 treatment group were obviously attenuated, along with the level of apoptosis. PR39 treatment group had distinctly improved tight junction associated proteins’ expression after EHEC O157:H7 caused injury. Additionally, the sequencing analysis of cecum microbiota showed that PR39 altered the abnormal increase in Bacteroides caused by EHEC O157:H7 and promoted the growth of probiotics such as Lactobacillus. In conclusion, cathelicidin-derived PR39 could effectively improve EHEC O157:H7-induced epithelial barrier injury, and dysfunction of immune and microbiota homeostasis in the intestinal tract, indicating that PR39 could be an excellent potential drug for zoonotic EHEC O157:H7-related intestinal disease.

Oral Administration of Bovine Lactoferrin-Derived Lactoferricin (Lfcin) B Could Attenuate Enterohemorrhagic Escherichia coli O157:H7 Induced Intestinal Disease through Improving Intestinal Barrier Function and Microbiota

Lactoferricin (Lfcin) B, derived from lactoferrin in whey, has attracted considerable attention because of its multiple biological functions. Zoonotic enterohemorrhagic Escherichia coli (EHEC) O157:H7 has adverse effects on intestinal epithelial barrier function, leading to serious intestinal disease. In this study, the EHEC O157:H7-induced intestinal dysfunction model was developed to investigate the effects of Lfcin B on EHEC O157:H7-induced epithelial barrier disruption and microbiota dysbiosis. Results showed that the inflammatory infiltration indexes in the jejunum of Lfcin B-treated animals were significantly decreased. Lfcin B administration also significantly improved ZO-1 and occludin expression following O157:H7-induced injury. Finally, microbiota analysis of the cecal samples revealed that Lfcin B inhibited the O157:H7-induced abnormal increase in Bacteroides. Therefore, Lfcin B efficiently attenuated O157:H7-induced epithelial barrier damage and dysregulation of inflammation status, while maintaining microbiota homeostasis in the intestine, indicating that it may be an excellent food source for prevention and therapy of EHEC O157:H7-related intestinal dysfunction.

Milk polar lipids modulate lipid metabolism, gut permeability, and systemic inflammation in high-fat-fed C57BL/6J ob/ob mice, a model of severe obesity

Dynamic interactions between lipid metabolism, gut permeability, and systemic inflammation remain unclear in the context of obesity. Milk polar lipids, lipids derived from the milk fat globule membrane, could positively affect the aforementioned obesity-related endpoints. This study aimed to test the hypotheses that milk polar lipids will reduce gut permeability, systemic inflammation, and liver lipid levels, and differentially affect the hepatic expression of genes associated with fatty acid synthesis and cholesterol regulation in preexisting obesity. We fed 3 groups of C57BL/6J ob/ob mice (n = 6 per group) for 2 wk: (1) a modified AIN-93G diet (CO) with 34% fat by energy; (2) CO with milk gangliosides (GG) at 0.2 g/kg of diet; and (3) CO with milk phospholipids (PL) at 10 g/kg of diet. The GG and PL were provided as semi-purified concentrates and replaced 2.0% and 7.2% of dietary fat by energy. The GG and PL did not affect total food intake, weight gain, fasting glucose, or gut permeability. The PL decreased liver mass and the mesenteric fat depot compared with the CO. The GG increased tight junction protein occludin in colon mucosa compared with the CO. The GG and PL decreased tight junction protein zonula occludens-1 in jejunum mucosa compared with the CO. Plasma endotoxin increased during the study but was unaffected by the treatments. Compared with the CO and GG, the PL increased plasma sphingomyelin and plasma IL-6. The GG and PL differentially regulated genes associated with lipid metabolism in the liver compared with the CO. Regarding general effects on lipid metabolism, the GG and PL decreased lipid levels in the liver and the mesenteric depot, and increased lipid levels in the plasma. Diet consumption decreased significantly when the ob/ob mice were kept in metabolic cages, which were not big enough and resulted in unwanted animal deaths. Future studies may keep this in mind and use better metabolic equipment for ob/ob mice. In conclusion, dietary milk polar lipids may have limited beneficial effects on gut barrier integrity, systemic inflammation, and lipid metabolism in the context of severe obesity.

Sphingolipid de novo biosynthesis is essential for intestine cell survival and barrier function

Serine palmitoyltransferase (SPT) is the rate-limiting enzyme for sphingolipid biosynthesis. SPT has two major subunits, SPTLC1 and SPTLC2. We previously found that liver Sptlc2 deficiency in early life impairs the development of adherens junctions. Here, we investigated the role of Sptlc2 deficiency in intestine. We treated Sptlc2-Flox/villin-Cre-ERT2 mice with tamoxifen (days 1, 2, and 3) to ablate Sptlc2 specifically in the intestine. At day 6 after tamoxifen treatment, Sptlc2-deficient mice had significantly decreased body weight with concurrent diarrhea and rectal bleeding. The number of goblet cells was reduced in both large and small intestine of Sptlc2-deficient mice compared with controls. Sptlc2 deficiency suppressed the level of mucin2 in the colon and increased circulating lipopolysaccharides, suggesting that SPT activity has a housekeeping function in the intestine. All Sptlc2-deficient mice died 7-10 days after tamoxifen treatment. Notably, supplementation with antibiotics and dexamethasone reduced lethality by 70%. We also found that colon specimens from patients with inflammatory bowel diseases had significantly reduced Sptlc2 expression, SPTLC2 staining, and goblet cell numbers. SPT activity is crucial for intestinal cell survival and barrier function.

Bovine dairy complex lipids improve in vitro measures of small intestinal epithelial barrier integrity

Appropriate intestinal barrier maturation is essential for absorbing nutrients and preventing pathogens and toxins from entering the body. Compared to breast-fed infants, formula-fed infants are more susceptible to barrier dysfunction-associated illnesses. In infant formula dairy lipids are usually replaced with plant lipids. We hypothesised that dairy complex lipids improve in vitro intestinal epithelial barrier integrity. We tested milkfat high in conjugated linoleic acid, beta serum (SureStart™Lipid100), beta serum concentrate (BSC) and a ganglioside-rich fraction (G600). Using Caco-2 cells as a model of the human small intestinal epithelium, we analysed the effects of the ingredients on trans-epithelial electrical resistance (TEER), mannitol flux, and tight junction protein co-localisation. BSC induced a dose-dependent improvement in TEER across unchallenged cell layers, maintained the co-localisation of tight junction proteins in TNFα-challenged cells with increased permeability, and mitigated the TEER-reducing effects of lipopolysaccharide (LPS). G600 also increased TEER across healthy and LPS-challenged cells, but it did not alter the co-location of tight junction proteins in TNFα-challenged cells. SureStart™Lipid100 had similar TEER-increasing effects to BSC when added at twice the concentration (similar lipid concentration). Ultimately, this research aims to contribute to the development of infant formulas supplemented with dairy complex lipids that support infant intestinal barrier maturation.

Dietary and Endogenous Sphingolipid Metabolism in Chronic Inflammation

Chronic inflammation is a common underlying factor in many major metabolic diseases afflicting Western societies. Sphingolipid metabolism is pivotal in the regulation of inflammatory signaling pathways. The regulation of sphingolipid metabolism is in turn influenced by inflammatory pathways. In this review, we provide an overview of sphingolipid metabolism in mammalian cells, including a description of sphingolipid structure, biosynthesis, turnover, and role in inflammatory signaling. Sphingolipid metabolites play distinct and complex roles in inflammatory signaling and will be discussed. We also review studies examining dietary sphingolipids and inflammation, derived from in vitro and rodent models, as well as human clinical trials. Dietary sphingolipids appear to influence inflammation-related chronic diseases through inhibiting intestinal lipid absorption, altering gut microbiota, activation of anti-inflammatory nuclear receptors, and neutralizing responses to inflammatory stimuli. The anti-inflammatory effects observed with consuming dietary sphingolipids are in contrast to the observation that most cellular sphingolipids play roles in augmenting inflammatory signaling. The relationship between dietary sphingolipids and low-grade chronic inflammation in metabolic disorders is complex and appears to depend on sphingolipid structure, digestion, and metabolic state of the organism. Further research is necessary to confirm the reported anti-inflammatory effects of dietary sphingolipids and delineate their impacts on endogenous sphingolipid metabolism.

In Vivo and In Vitro Study on the Efficacy of Terpinen-4-ol in Dextran Sulfate Sodium-Induced Mice Experimental Colitis

The purpose of this study was to investigate the protective effects of Terpinen-4-ol (TER) on dextran sulfate sodium (DSS)-induced experimental colitis and clarify the possible mechanisms. In vivo, an acute colitis model was used to confirm the anti-inflammatory activity and the possible mechanisms of TER in C57BL/6 and NLRP3^−/− mice. In vitro, we performed further study, using RAW264.7 cells and Caco-2 cells, to confirm the molecular mechanisms of TER on inflammatory response. In C57BL/6 mice, TER alleviated DSS-induced disease activity index (DAI), colon length shortening, colonic pathological damage, and myeloperoxidase (MPO) activities. The production of pro-inflammatory mediators was significantly decreased by TER. Furthermore, TER inhibited NF-κB and NLRP3 inflammasome activation. Surprisingly, TER reduced the plasmatic lipopolysaccharide (LPS) concentration and re-balanced Escherichia coli (E. coli) and Lactobacillus levels. In addition, TER prevented the impairment of colon epithelium barrier by regulating the expression of zonula occludens-1 and occludin. In vitro, the results showed that TER significantly suppressed NLRP3 inflammasome activation in LPS-stimulated RAW264.7 cells, as indicated by decreased expression of NLRP3 and caspase-1, and lowered interleukin-1β secretion. In contrast, mice deficient for NLRP3 were less sensitive to DSS-induced acute colitis, and TER treatment exerted little protective effect on DSS-induced intestinal inflammation in NLRP3^−/− mice. The protective effect of TER may be largely attributed to its inhibition of NLRP3 inflammasome activation in colon. Taken together, our findings showed that TER might be a potential agent for the treatment of ulcerative colitis.

Dietary Allium hookeri reduces inflammatory response and increases expression of intestinal tight junction proteins in LPS-induced young broiler chicken

We undertook a study to assess the effects of Allium hookeri (AH) root and fermented root on inflammation and intestinal integrity of lipopolysaccharide (LPS)-challenged broiler chickens. Birds were assigned to six groups (n = 25 birds/treatment) and fed with basal diets (CON) or basal diets supplemented with AH root or fermented root at two concentrations (1 or 5%). At 7 d of age, five groups (n= 125) in each dietary treatment were injected with LPS (1 mg/kg body weight), and the remaining 25 birds were injected with sterile phosphate-buffered saline (PBS) as a negative control. LPS challenge significantly reduced average body weight gain at 24 h post-injection compared with PBS control. Fermented root supplementation increased average body weight gain by 1% compared with the LPS-challenged control. Serum α- 1-AGP levels, interleukin (IL)-1β, IL-8, tumor necrosis factor superfamily member 15 (TNFSF15), and LPS-induced tumor necrosis factor-α factor (LITAF) transcript levels were significantly higher in the small intestine in LPS-injected chickens. However α-1-AGP levels were reduced by AH root or fermented root (1 and 5%) supplementation and IL-1β, IL-8, and LITAF were also down-regulated by root and fermented root (1 and 5%) supplementation. The reduced expression of tight junction proteins (junctional adhesion molecule 2 (JAM2) and occludin) and intestinal mucin 2 (MUC2) by LPS challenge was reversed by root or fermented root (1 and 5%) supplementation. These findings demonstrate that dietary AH root and fermented root influence antiinflammatory activity and tight junction protein expression in LPS-induced chickens.

Anti-inflammaging effects of Lactobacillus brevis OW38 in aged mice

In the present study, lactic acid bacteria (LAB) strains were collected from kimchi and were screened to isolate strains that inhibit lipopolysaccharide (LPS) production by Escherichia coli and p16 expression and nuclear factor-kappa B (NF-κB) activation in LPS-stimulated macrophages. Oral administration of Lactobacillus brevis OW38 (1×109 cfu/mouse) to aged mice (male, 18 months old) for 8 weeks reduced the LPS level in colon fluid and blood. In addition, OW38 treatment also reduced the ratio of Firmicutes or Proteobacteria to Bacteroidetes, which was significantly higher in aged mice than in young mice. Treatment with OW38 in aged mice inhibited the expression of inflammatory markers, such as myeloperoxidase, tumour necrosis factor (TNF), and interleukin (IL)-1β, and inhibited NF-κB activation. Furthermore, it induced the expression of colonic tight junction proteins zonula occludens-1, occludin, and claudin-1. OW38 treatment also suppressed the expression of senescence markers p16, p53, and SAMHD1 in the colon and the hippocampus of aged mice. In addition, it significantly restored spontaneous alternation as well as the expression of brain-derived neurotrophic factor and doublecortin in aged mice compared to that in young mice (P<0.05). Based on these findings, we conclude that OW38 treatment may ameliorate aging-associated colitis and memory impairment by inhibiting gut microbiota LPS production, NF-κB activation, and p16 expression.

Mucosal Interactions between Genetics, Diet, and Microbiome in Inflammatory Bowel Disease

Numerous reviews have discussed gut microbiota composition changes during inflammatory bowel diseases (IBD), particularly Crohn’s disease (CD). However, most studies address the observed effects by focusing on studying the univariate connection between disease and dietary-induced alterations to gut microbiota composition. The possibility that these effects may reflect a number of other interconnected (i.e., pantropic) mechanisms, activated in parallel, particularly concerning various bacterial metabolites, is in the process of being elucidated. Progress seems, however, hampered by various difficult-to-study factors interacting at the mucosal level. Here, we highlight some of such factors that merit consideration, namely: (1) the contribution of host genetics and diet in altering gut microbiome, and in turn, the crosstalk among secondary metabolic pathways; (2) the interdependence between the amount of dietary fat, the fatty acid composition, the effects of timing and route of administration on gut microbiota community, and the impact of microbiota-derived fatty acids; (3) the effect of diet on bile acid composition, and the modulator role of bile acids on the gut microbiota; (4) the impact of endogenous and exogenous intestinal micronutrients and metabolites; and (5) the need to consider food associated toxins and chemicals, which can introduce confounding immune modulating elements (e.g., antioxidant and phytochemicals in oils and proteins). These concepts, which are not mutually exclusive, are herein illustrated paying special emphasis on physiologically inter-related processes.

Porcine lactoferrin-derived peptide LFP-20 protects intestinal barrier by maintaining tight junction complex and modulating inflammatory response

LFP-20, a 20-amino acid antimicrobial peptide in the N terminus of porcine lactoferrin, has antimicrobial and immunomodulatory activities. This study assessed the protective effects of LFP-20 on LPS-induced intestinal damage in a LPS-induced mouse model and in vitro, using intestinal porcine epithelial cell line 1 (IPEC-1) cells. LFP-20 prevented LPS-induced impairment in colon epithelium tissues, infiltration of macrophages or leukocytes, histological evidence of inflammation and increased levels of TNF-a, IL-6 and IFN-γ. LFP-20 increased the expression of zonula occludens-1, occludin and claudin-1 and reduced permeability as well as apoptosis of the colon in LPS-treated mice. In IPEC-1 cells, LFP-20 increased transepithelial electrical resistance and tight junction expression. Moreover, we found LFP-20 decreased the MyD88 and AKT levels to affect the NF-κB signaling pathway, to modulate inflammation response and tight junction networks in the processing of LPS stimulation. In summary, LFP-20 prevents the inflammatory response and disruption of tight junction structure induced by LPS, suggesting the potential use of LFP-20 as a prophylactic agent to protect intestinal barrier function.

Fostering Inflammatory Bowel Disease: Sphingolipid Strategies to Join Forces

Complex sphingolipids are essential structural components of intestinal membranes, providing protection and integrity to the intestinal mucosa and regulating intestinal absorption processes. The role of sphingolipid signaling has been established in numerous cellular events, including intestinal cell survival, growth, differentiation, and apoptosis. A significant body of knowledge demonstrates that intestinal sphingolipids play a crucial role, as such and through their signaling pathways, in immunity and inflammatory disorders. In this review, we report on and discuss the current knowledge on the metabolism, signaling, and functional implications of sphingolipids in inflammatory bowel disease (IBD), focusing on the different aspects of sphingolipid actions on inflammatory responses and on the potential of sphingolipid-targeted molecules as anti-IBD therapeutic agents.

Increased catabolism and decreased unsaturation of ganglioside in patients with inflammatory bowel disease

AIM: To investigate whether accelerated catabolism of ganglioside and decreased ganglioside content contribute to the etiology of pro-inflammatory intestinal disease.

METHODS: Intestinal mucosa from terminal ileum or colon was obtained from patients with ulcerative colitis or inflammatory Crohn’s disease (n = 11) undergoing bowel resection and compared to control samples of normal intestine from patients with benign colon polyps (n = 6) and colorectal cancer (n = 12) in this observational case-control study. Gangliosides and phospholipids of intestinal mucosa were characterized by class and ceramide or fatty acid composition using liquid chromatography triple-quad mass spectrometry. Content and composition of ganglioside classes GM1, GM3, GD3, GD1a, GT1 and GT3 were compared among subject groups. Content and composition of phospholipid classes phosphatidylcholine (PC) and phosphatidylethanolamine were compared among subject groups. Unsaturation index of individual ganglioside and phospholipid classes was computed and compared among subject groups. Ganglioside catabolism enzymes beta-hexosaminidase A (HEXA) and sialidase-3 (NEU3) were measured in intestinal mucosa using western blot and compared among subject groups.

RESULTS: Relative GM3 ganglioside content was 2-fold higher (P < 0.05) in intestine from patients with inflammatory bowel disease (IBD) compared to control intestine. The quantity of GM3 and ratio of GM3/GD3 was also higher in IBD intestine than control tissue (P < 0.05). Control intestine exhibited 3-fold higher (P < 0.01) relative GD1a ganglioside content than IBD intestine. GD3 and GD1a species of ganglioside containing three unsaturated bonds were present in control intestine, but were not detected in IBD intestine. The relative content of PC containing more than two unsaturated bonds was 30% lower in IBD intestine than control intestine (P < 0.05). The relative content of HEXA in IBD intestine was increased 1.7-fold (P < 0.05) and NEU3 was increased 8.3-fold (P < 0.01) compared to normal intestine. Intestinal mucosa in IBD is characterized by increased GM3 content, decreased GD1a, and a reduction in polyunsaturated fatty acid constituents in GD3, GD1a and PC.

CONCLUSION: This study suggests a new paradigm by proposing that IBD occurs as a consequence of increased metabolism of specific gangliosides.

Ganglioside GD1a suppresses LPS-induced pro-inflammatory cytokines in RAW264.7 macrophages by reducing MAPKs and NF-κB signaling pathways through TLR4

Gangliosides, sialic acid-containing glycosphingolipids, have been considered to be involved in the development, differentiation, and function of nervous systems in vertebrates. However, the mechanisms for anti-inflammation caused by gangliosides are not clear. In this paper, we investigated the anti-inflammation effects of ganglioside GD1a by using RAW264.7 macrophages. Our data demonstrated that treatment of macrophages with lipopolysaccharide significantly increased the production of NO and pro-inflammatory cytokines. GD1a suppressed the induction of iNOS and COX-2 mRNA and protein expression and secretory pro-inflammatory cytokines in culture medium, such as TNFα, IL-1α and IL-1β. In addition, LPS-induced phosphorylation of mitogen-activating protein kinases and IκBα degradation followed by translocation of the NF-κB from the cytoplasm to the nucleus were attenuated after GD1a treatment. Furthermore, GD1a probably inhibited LPS binding to macrophages and LPS-induced accumulation between TLR4 and MyD88. Taken together, the results demonstrated that ganglioside GD1a inhibited LPS-induced inflammation in RAW 264.7 macrophages by suppressing phosphorylation of mitogen-activating protein kinases and activation of NF-κB through repressing the Toll-like receptor 4 signaling pathway.

Orally administrated Lactobacillus pentosus var. plantarum C29 ameliorates age-dependent colitis by inhibiting the nuclear factor-kappa B signaling pathway via the regulation of lipopolysaccharide production by gut microbiota

To evaluate the anti-inflammaging effect of lactic acid bacteria (LAB) on age-dependent inflammation, we first screened and selected a tumor necrosis factor (TNF)-α and reactive oxygen species (ROS)-inhibitory LAB, Lactobacillus pentosus var. plantarum C29, among the LABs isolated from fermented vegetables using LPS-stimulated mouse peritoneal macrophages. Oral administration of C29 (2 × 109 CFU/rat) for 8 weeks in aged Fischer 344 rats (age, 16 months) inhibited the expression of the inflammatory markers myeloperoxidase, inducible nitric oxide (NO) synthase, cyclooxygenase-2, pro-inflammatory cytokines tumor necrosis factor (TNF)-α and IL-6 and the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), activator protein 1 (AP1), and mitogen-activated protein kinases (MAPKs). Treatment with C29 induced the expression of tight junction proteins ZO-1, occludin, and claudin-1, and reduced intestinal microbial LPS and plasmatic LPS levels and ROS, as well as the Firmicutes to Bacteroidetes ratio, which is significantly higher in aged rats than in young rats. C29 treatment also reduced plasmatic reactive oxygen species, malondialdehyde, C-reactive protein, and TNF-α, and suppressed expression of senescence markers p16 and p53 in the colon of the aged rats, but increased SIRT 1 expression. Based on these findings, we concluded that C29 treatment may suppress aging-dependent colitis by inhibiting NF-κB, AP1, and MAPK activation via the inhibition of gut microbiota LPS production and the induction of tight junction protein expression.

Antimicrobial peptide Cathelicidin-BF prevents intestinal barrier dysfunction in a mouse model of endotoxemia

Intestinal barrier functions are altered during the development of sepsis. Cathelicidin antimicrobial peptides, such as LL-37 and mCRAMP, can protect animals against intestinal barrier dysfunction. Cathelicidin-BF (C-BF), a new cathelicidin peptide purified from the venom of the snake Bungarus fasciatus, has been shown to have both antimicrobial and anti-inflammatory properties. This study investigated whether C-BF pretreatment could protect the intestinal barrier against dysfunction in a mouse model of endotoxemia, induced by intraperitoneal injection of LPS (10mg/kg). Mice were treated with low or high dose C-BF before treatment with LPS, and samples were collected 5h after LPS treatment. C-BF reduced LPS induced intestinal histological damage and gut permeability to 4 KD Fluorescein-isothiocyanate-conjugated dextran. Pretreatment with C-BF prevented LPS induced intestinal tight junction disruption and epithelial cell apoptosis. Moreover, C-BF down regulated the expression and secretion of TNF-α, a process involving the NF-κB signaling pathway. C-BF also reduced LPS induced TNF-α expression through the NF-κB signaling pathway in mouse RAW 264.7 macrophages. These findings indicate that C-BF can prevent gut barrier dysfunction induced by LPS, suggesting that C-BF may be used to develop a prophylactic agent for intestinal injury in endotoxemia.