Fig 1 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Source publication
Background
Lipopolysaccharide (LPS) induces acute liver injury and the complex mechanisms include the activation of toll like receptor 4 (TLR4) signaling pathway in many species. However, immuno-pathological changes during TLR4 signaling under LPS stress in acute liver injury is poorly understood in avian species. The present investigation was ther...
Citations
... Te proportion of positive cells in each high magnifcation feld (× 100) and the intensity of cell coloration were scored using the semiquantitative integration method. Color intensity score: no coloration was scored as 0, light yellow coloration as 1, brown coloration as 2, and tan coloration as 3. Proportion of positive cells scored: < 1% as 0, 1%-25% as 1, 26%-50% as 2, and > 50% as 3. Te total immunohistochemistry score was the sum of the above two items, with a total score of 0-1: negative, 1-2: weakly positive, 2-3: moderately positive, 3-4: more strongly positive, and 4-5: severely positive [24]. ...
Aloe vera is an important raw material for medicine and food, and aloe-emodin (AE) is one of the main extracts of Aloe vera. The aim of this study was to investigate the inhibitory effect of AE on multidrug-resistant Escherichia coli (MDR-E. coli) and the anti-inflammatory mechanism of this pathogenic bacterial infection. The minimum inhibitory concentration of AE against MDR-E. coli was determined in vitro. The potential therapeutic targets and signaling pathways of AE on inflammation were predicted by network pharmacology, and a mouse infection model was constructed by intraperitoneal injection of pathogenic bacteria and treated with AE. The results showed that AE had a better bacteriostatic effect and modulated the inflammatory response by affecting the expression of multiple inflammatory factors, and AE treatment significantly reduced symptoms such as inflammation, organ swelling, and bacterial load in the mouse model. The results suggest that AE may be an important active ingredient for Aloe vera to exert therapeutic health effects.
... TLRs recognize lipopolysaccharide (LPS), a key component of Salmonella, thereby triggering the host immune response (Higuchi et al., 2008;Keestra et al., 2013;Nawab et al., 2019). Inhibition of TLR4, TLR2, and TLR21 expressions in chicken leukocytes reduce the resistance ability to S. Enteritidis infection in young chickens (Huang et al., 2017). After infected with Newcastle disease viruses (NDV), the expression of the chicken TLR7 gene was increased in different tissues (Yan et al., 2017). ...
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a common zoonotic pathogen that not only causes gastroenteritis or death of livestock and poultry but also poses a serious threat to human health, causing severe economic losses to the poultry industry and society. Herein, RNA-sequencing (RNA-seq) was used to analyze the transcriptome variation of chicken cecum at four different time points (1, 3, 7, and 14 days) following S. Enteritidis infection. There were 529, 1477, 476, and 432 differentially expressed genes (DEGs) in the cecum at four different days post-infection (dpi), respectively. The DEGs were significantly enriched in various immune-related pathways on 3 dpi and 7 dpi, such as cytokine-cytokine-receptor interaction and Toll-like receptor signaling pathway. DEGs were significantly enriched in several metabolic pathways on 14 dpi. Gene ontology (GO) enrichment of DEGs showed that up-regulated genes were significantly enriched in immune-related terms on 3 and 7 dpi. On 14 dpi, up-regulated genes were mainly enriched in the signaling-related terms, while the down-regulated genes were primarily enriched in the metabolic-related terms. Based on weighted gene co-expression network analysis (WGCNA), the key modules related to energy, non-coding processes, immunity, and development-related functions were identified at 1, 3, 7, and 14 dpi, respectively, and 5, 8, 6, and 5 hub genes were screened out, respectively. This study demonstrated that the chicken cecal transcriptome regulation responding to S. Enteritidis infection is time-dependent. The regulation of S. Enteritidis infection in chickens is coordinated by multiple systems, mainly involving immunity, metabolism, and signal transduction. Both 3 and 7 dpi are key time points for immune response. As the infection progresses, metabolism-related pathways were increasingly identified. This change reflects the dynamic adjustment between immune response and metabolism in Jining Bairi chickens following S. Enteritidis infection. These results suggested that starting from 3 dpi, the chickens gradually transition from an immune response triggered by S. Enteritidis infection to a state where they adapt to the infection by modulating their metabolism.
... TLR4 activation by LPS triggers a signaling cascade involving MyD88, an adaptor protein that leads to the degradation of IκB, a critical inhibitor of NF-κB. Degradation of IκB allows NF-κB to translocate to the nucleus and drive the transcription of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 (Huang et al., 2017;Xiao et al., 2024). ...
The broiler chickens’ immune system fully develops a few weeks after hatching, leaving them susceptible to disease during the early post-hatching phase. This study investigated effects of in ovo delivery of carvacrol on the expression of immune-related genes following an Escherichia coli lipopolysaccharide (LPS) challenge at d7 post-hatch. The experiment was designed as a 2 × 2 factorial arrangement with two in ovo treatments (saline or carvacrol) and two LPS challenged groups (yes or no): (1) saline + no challenge (control), (2) saline + LPS, (3) carvacrol + no challenge, (4) carvacrol + LPS. Hatchability and performance parameters were determined before, and organ weights after the LPS challenge. Immune-related gene expression was assessed in the jejunum and spleen post-challenge. At d7, the carvacrol-treated group had lower FI (Δ11 g, P = 0.02) compared to the saline group. In the jejunum, a significant interaction (P = 0.003) was found between in ovo treatment and LPS challenge for IFN-γ expression, which was highest in the saline + LPS and carvacrol + no challenge groups. Carvacrol delivery resulted in lower IL-8 (P = 0.03) and IκB (P = 0.04) expression, regardless of LPS challenge. In the spleen, a significant interaction (P = 0.03) showed that carvacrol downregulated expression of pro-inflammatory IL-1β, observed in the saline + LPS group. For NF-κB and TLR4, LPS challenge did not affect saline-treated chickens, but lowered expression of these genes in carvacrol-treated chickens (P = 0.03 and 0.02, respectively). IFN-γ expression did not differ between in ovo delivery treatments after LPS challenge but was higher (P = 0.02) in the carvacrol-treated chickens than in the saline-treated chickens for the non-challenged groups. These findings indicate an anti-inflammatory effect of in ovo carvacrol delivery by inhibiting LPS-induced downregulation of NF-κB and mitigating IL-1β and TNF-α expression. Carvacrol stimulated IFN-γ expression, potentially modulating adaptive immune responses. In conclusion, in ovo carvacrol delivery could mitigate release of key inflammatory cytokines, while increasing IFN-γ.
... This study proposes that a safer SG vaccine can be developed through bacterial strain manipulation using genetic engineering to address this gap. It is well-established that bacterial lipopolysaccharides (LPS) initiate pro-inflammatory immune responses and endotoxicity, which can be lethal to the host, especially at a young age [7]. Lipid A and its acyl chains in LPS play a central role in triggering inflammatory cytokines. ...
Fowl typhoid (FT) poses a significant threat to the poultry industry and can cause substantial economic losses, especially in developing regions. Caused by Salmonella Gallinarum (SG), vaccination can prevent FT. However, existing vaccines, like the SG9R strain, have limitations, including residual virulence and potential reversion of pathogenicity. This study aims to develop safer and more effective SG vaccine strains through targeted genetic modifications, focusing on genes involved in lipopolysaccharide (LPS) biosynthesis and modification. We evaluated two novel mutant SG strains, JOL3015 and JOL3016, carrying in-frame deletions in ΔlonΔrfaLΔarnT and ΔlonΔrfaLΔpagL, respectively. Intramuscular immunisation of 4-week-old young birds with JOL3015 and JOL3016 strains showed minimal impact on their growth. However, the immunisation significantly increased antigen-specific IgY, sIgA secretion, and CD4⁺ and CD8⁺ T-cell responses while inducing lower pro-inflammatory cytokine levels than SG9R. Histopathological evaluations revealed substantial protection in the immunised birds, with minimal tissue damage and inflammatory responses, thus reducing the in vivo bacterial burden. Furthermore, none of the immunised birds died. This outcome highlights the significant safety and protection the selected genetic modifications conferred. Our results indicate that JOL3016 provided comparable protective outcomes on par with SG9R, yet with significantly lower endotoxicity responses during the lethal challenge with SG WT JOL422. The novel detoxified SG strains, particularly JOL3016, offer a promising alternative to existing vaccines for FT. They provide effective protection with minimal impact on poultry growth, thereby minimising the risks associated with reversion and endotoxicity. The study highlights the potential of genetically engineered vaccine strains in improving poultry health and productivity, emphasising the importance of continued research.
Supplementary Information
The online version contains supplementary material available at 10.1186/s13567-024-01413-8.
... This study proposes that a safer SG vaccine can be developed through bacterial strain manipulation using genetic engineering to address this gap. It is well-established that bacterial lipopolysaccharides (LPS) initiate pro-inflammatory immune responses and endotoxicity, which can be lethal to the host, especially at a young age [7]. Lipid A and its acyl chains in LPS play a central role in triggering inflammatory cytokines. ...
... In recent years, in-depth studies on TLR4 genes in several species, such as humans (Arbour et al. 2000), mice (Wu et al. 2007), chickens (Huang et al. 2017) and sheep (Fenhammar et al. 2014) have revealed that TLR4 plays an important role in inflammation, but the study of TLR4 in L. yarkandensis has not been reported yet. therefore, in this study, the sequence of the coding region of TLR4 in L. yarkandensis was cloned, and the relative transcript amount of TLR4 genes in various regions of the intestinal tract in L. yarkandensis and O. cuniculus was analyzed through analyses by applying real-time quantitative fluorescent PCR technology. ...
Lepus yarkandensis live year-round in harsh desert environments and are less susceptible to enteritis. The living conditions of Oryctolagus cuniculus in captivity were suitable, but they were highly susceptible to death by Gram-negative bacteria infected with inflammatory bowel disease complex.TLR4 is closely related to the occurrence of enteritis, and the neighbor-joining topology based on the 12S rDNA sequences showed that the relationship between O. cuniculus and L. yarkandensis is as high as 98%.Therefore, we chose O. cuniculus and L. yarkandensis for comparative study.The purpose of this study was to investigate the role of Toll-like receptor 4 (TLR4) in the regulation of immunity and inflammation in the intestinal tract of L. yarkandensis. In this study, the TLR4 gene was cloned for the first time in the colon of L. yarkandensis. The expression of TLR4 in the intestinal tissues of L. yarkandensis and O. cuniculus was detected by histological observation, real-time fluorescence quantification PCR(qRT-PCR), and protein blotting (Western blot).An LPS-induced cell inflammation model was constructed in vitro, and ELISA was used to examine the effect of pEGFP-N1-TLR4 and siRNA knockout on the anti-inflammatory ability of the TLR4 gene. The results showed that the open reading frame of the L. yarkandensis TLR4 gene was 2520 bp in length. Compared with the sequence of O. cuniculus, there were 15 differences in the TLR4 amino acid sequence of L. yarkandensis, 12 of which occurred in the LRR domain and 2 in the TIR domain, and the sequence changed from G to D at position 298. Immunohistochemistry showed that TLR4 was mainly expressed in the epithelial cells of the colon L. yarkandensis, and the expression level of TLR4 in the cecum and colon was significantly lower compared with that of O. cuniculus. qRT-PCR and Western blot results showed that the expression level of TLR4 in the colon of L. yarkandensis was significantly lower than that of O. cuniculus. At the cellular level, ELISA showed that overexpression of the TLR4 protein in L. yarkandensis could reduce the LPS-induced inflammatory response. Therefore, according to the above results, the protein structure and function of L. yarkandensis TLR4 may be different due to the change of nucleotide, which affects its binding with LPS and the activation of downstream molecules, so that L. yarkandensis is not prone to enteritis and can adapt to the harsh desert environment for a long time. This study also laid the foundation for improving the disease resistance of O. cuniculus and promoting the development and utilization of genes in L. yarkandensis.
... TLR4, an LPS recognition receptor, combines with the LPS, and thereby activates NF-κB via the MyD88 protein, causing the release of inflammatory cytokines [53,54]. Previous research in broilers by Huang et al. [55] implied that LPS administration up-regulated the expression of TLR4 and its downstream molecules (MyD88, NF-κB, TNF-α and IL-1β) in the chicken liver. The tannins have been proven to suppress the activation of the TLR4 signaling pathway and the release of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IFN-γ) [43]. ...
... When pathogenic bacteria attack the intestinal mucosa, the balance between reactive oxygen species production and the antioxidant defense capacity of the body will be disrupted [56]. It has been proven that intraperitoneal LPS injection can result in intestinal inflammation and oxidative stress, concurrently [24,55]. Consistently, in the present study, LPS challenge elevated the MDA concentration and reduced the relative mRNA expressions of HO-1, SOD1, and SOD2 in the intestinal mucosa, which was mitigated to levels observed in the CON group by dietary CGT supplementation. ...
Simple Summary
In intensive farms, broilers are easily infected by harmful bacteria, resulting in intestinal damage and affecting their health. The prohibition of antibiotics makes it necessary to find new antibacterial products, especially native substances. As a kind of traditional Chinese herbal medicine, Chinese gallotannins (CGT) containing tannins have antioxidant, anti-inflammatory, and bactericidal effects. Therefore, in this experiment, we established a model of intestinal injury in broilers by intraperitoneal administration of lipopolysaccharide (LPS) in Escherichia coli to explore the protective effect of CGT on intestinal injury in broilers induced by LPS challenge. The results show that CGT effectively alleviated intestinal mucosal injury and repaired the intestinal barrier effectively by repairing intestinal villus morphology, inhibiting apoptosis, decreasing pro-inflammatory factors, and stabilizing microbial ecology, thus raising the body weight to a normal level. A dietary supplementation of 300 mg/kg CGT might be a potential way to substitute antibiotics to attenuate intestinal injury induced by LPS in broilers.
Abstract
This experiment was conducted to study the protective effects of dietary Chinese gallotannins (CGT) supplementation against Escherichia coli lipopolysaccharide (LPS)-induced intestinal injury in broilers. Four hundred and fifty healthy Arbor Acres broilers (one-day-old) were randomly divided into three groups: (1) basal diet (CON group), (2) basal diet with LPS challenge (LPS group), and (3) basal diet supplemented with 300 mg/kg CGT as well as LPS challenge (LPS+CGT group). The experiment lasted for 21 days. Intraperitoneal LPS injections were administered to broilers in the LPS group and the LPS+CGT group on days 17, 19, and 21 of the trial, whereas the CON group received an intraperitoneal injection of 0.9% physiological saline. Blood and intestinal mucosa samples were collected 3 h after the LPS challenge. The results showed that LPS administration induced intestinal inflammation and apoptosis and damaged small intestinal morphology and structure in broilers. However, dietary supplementation with CGT alleviated the deleterious effects on intestinal morphology and barrier integrity caused by the LPS challenge, while also reducing intestinal apoptosis and inflammation, enhancing intestinal antioxidant capacity, and increasing cecal microbial alpha diversity in the LPS-challenged broilers. Therefore, our findings demonstrated that a 300 mg/kg CGT addition could improve intestinal morphology and gut barrier structure, as well as maintaining bacterial homeostasis, in broilers exposed to LPS. This might partially be attributed to the reduced cell apoptosis, decreased inflammatory response, and enhanced antioxidant capacity in the small intestinal mucosa.
... To address this gap, a safer SG vaccine can be developed through bacterial strain manipulation using genetic engineering. It is a known fact that bacterial lipopolysaccharides (LPS) initiate proin ammatory immune responses and endotoxicity, which can be lethal to the host, especially at a young age [7]. Lipid A and its acyl chains in LPS play a central role in triggering in ammatory cytokines. ...
Fowl typhoid (FT) poses a significant threat to the poultry industry, especially in developing regions, causing substantial economic losses. Caused by Salmonella Gallinarium, FT can be prevented by vaccination, but existing vaccines like the SG9R strain have limitations, including residual virulence and potential reversion of pathogenicity. This study aims to develop safer and more effective SG vaccine strains through targeted genetic modifications, focusing on genes involved in lipopolysaccharide (LPS) biosynthesis and modification. We evaluated two novel mutant SG strains, JOL3015 and JOL3016, carrying in-frame deletions in Δ lon Δ rfaL Δ arnT and Δ lon Δ rfaL Δ pagL respectively. Intramuscular immunization with JOL3015 and JOL3016 strains showed minimal impact on the growth of 4-week-old young birds, significantly increased antigen-specific IgY, sIgA secretion, and CD4 ⁺ and CD8 ⁺ T cell responses, while inducing lower proinflammatory cytokine levels than SG9R. Histopathological evaluations revealed substantial protection in immunized birds, with minimal tissue damage and inflammatory responses, reducing the in vivo bacterial burden. None of the immunized birds died, highlighting the significant safety and protection conferred by the selected genetic modifications. Our results indicate that JOL3016 provided comparable protective outcomes on par with SG9R, yet with significantly lower endotoxicity responses during the lethal challenge with SG WT JOL422. The novel detoxified SG strains, particularly JOL3016, offer a promising alternative to existing vaccines for FT. They provide effective protection with minimal impact on poultry growth, minimizing the risks associated with reversion and endotoxicity. This study highlights the potential of genetically engineered vaccine strains in improving poultry health and productivity, emphasizing the importance of continued research.
... As these effects are similar to those observed in mammalian studies, PAMPs may also induce hepatic injury in birds. Indeed, LPS induces hepatic injury in young chickens [17,18]. The liver is a major metabolic organ in vertebrates; therefore, PAMP-induced hepatic injury leads to a loss of productivity in poultry production. ...
... These results were also contrary to those of previous studies in rodents, in which serum AST and LDH activities were increased [4,24]. Interestingly, LPS-induced hepatic injury has also been observed in young chickens [17,18], although the experimental conditions, including age and LPS source, were different from those of our study. In our preliminary histological experiment, LPS injection induced no apparent hepatic injury (characterized by hemorrhage; data not shown). ...
The pathogen-associated molecular patterns (PAMPs) lipopolysaccharide (LPS) and zymosan, derived from gram-negative bacteria and fungi, respectively, activate the innate immune system and cause injury to multiple organs, including the liver and intestine, in mammals. In rodents, PAMP-induced injury has been demonstrated to be potentiated by co-administration of D-galactosamine (D-GalN) in rodents. However, whether PAMPs and D-GalN collectively cause organ injury in birds remains unclear. The present study aimed to measure the effects of intraperitoneal injection of D-GalN with LPS or zymosan on parameters related to hepatic injury in chicks (Gallus gallus). Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities were not affected by intraperitoneal injection of D-GalN alone. Although these activities were not affected by LPS injection alone, they were increased by combining LPS with D-GalN. In contrast, plasma AST, ALT, and LDH activities were not affected by zymosan, both alone and with D-GalN. The expression of mRNAs for interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) in the liver was significantly increased by the combination of LPS and D-GalN. In contrast, combining zymosan with D-GalN significantly increased iNOS mRNA expression, irrespective of hepatic injury. These results suggest that IL-6 may be the cause and/or result of hepatic injury in chicks. Additionally, chicks are tolerant to the hepatic effects of D-GalN, LPS, or zymosan alone.
... Toll-like receptors (TLRs) are considered to be important components of the innate immune response (11). They are expressed by both hepatocytes and Kupffer cells and serve important roles in hepatic inflammation (12)(13)(14). ...
Inflammation is involved in the pathological process underlying a number of liver diseases. Bilobalide (BB) is a natural compound from Ginkgo biloba leaves that was recently demonstrated to exert hepatoprotective effects by inhibiting oxidative stress in the liver cancer cell line HepG2. The anti-inflammatory activity of BB has been reported in recent studies. The major objective of the present study was to investigate whether BB could attenuate inflammation-associated cell damage. HepG2 cells were cultured with lipopolysaccharide (LPS) and BB, and cell damage was evaluated by measuring cell viability using MTT assay. The activity of the NF-κB signaling pathway was assessed by measuring the levels of IκBα, NF-κB p65, phosphorylated (p)-IκBα, p-p65, p65 DNA-binding activity and inflammatory cytokines IL-1β, IL-6 and TNF-α. A toll-like receptor (TLR)4 inhibitor (CLI-095) was used to detect the involvement of TLR4 in cell injury caused by LPS. In addition, the PI3K/Akt inhibitor LY294002 was applied to explore the involvement of the PI3K/Akt axis in mediating the effects of BB. The results demonstrated that LPS induced HepG2 cell injury. LPS also elevated the levels of p-IκBα, p-p65, p65 DNA-binding activity and inflammatory cytokines. However, CLI-095 significantly attenuated the LPS-induced cell damage and inhibited the activation of NF-κB signaling. BB also dose-dependently attenuated the LPS-induced cell damage, activation of NF-κB signaling and TLR4 overexpression. Furthermore, it was observed that LY294002 diminished the cytoprotective effects of BB on cell injury, TLR4 expression and NF-κB activation. These findings indicated that BB could attenuate LPS-induced inflammatory injury to HepG2 cells by regulating TLR4-NF-κB signaling.
