Mitogen-activated protein kinase phosphatase-1 prevents lipopolysaccharide-induced apoptosis in immature rat intestinal epithelial cells

Cod (Gadus) skin collagen peptide powder reduces inflammation, restores mucosal barrier function, and inhibits fibrosis in dextran sodium sulfate-induced colitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology. Cod (Gadus), a kind of herb from the Chinese herb. Traditionally, it has used to treat trauma, reduce swelling and relieve pain in order to exert its anti-inflammatory activity. Recent reports based on its hydrolyzed or enzymatic extracts have shown its anti-inflammatory, mucosal barrier protecting properties. However, its mechanism of improvement in ulcerative colitis is not clear.

AIM OF THE STUDY

This study aimed to explore the preventive and protective effect of cod skin collagen peptide powder (CP) on mice with UC and to explore the underlying mechanism.

MATERIALS AND METHODS

Mice with dextran sodium sulfate (DSS)-induced UC were treated with CP by gavage, and the anti-inflammatory effects of CP were assessed using general physical, pro-inflammatory cytokine, histopathological, immunohistochemical, macrophage flow cytometry, and inflammatory signaling pathway assays.

RESULTS

CP ameliorates inflammation by upregulating mitogen-activated protein kinase phosphatase-1 (MKP-1) and thereby decreasing the phosphorylation levels of P38 and JNK. It also polarizes macrophages in the colon towards the M2 phenotype, which helps to reduce tissue damage and promotes colon repair. At the same time, CP also inhibits the development of fibrosis, one of the complications of UC, by upregulating ZO-1, Occludin, and downregulating α-SMA, Vimentin, Snail, and Slug.

CONCLUSION

In this study, we found CP reduced inflammation in mice with UC by inducing MKP-1 expression, which caused dephosphorylation of mitogen-activated protein kinase (MAPK). CP also restored mucosal barrier function and inhibited the development of fibrosis complicating UC in these mice. Taken together, these results suggested that CP improved the pathological manifestations of UC in mice, suggesting that it can play a biological role as a nutritional supplement for preventing and treating UC.

The effect of normalisation and error model choice on the distribution of the maximum likelihood estimator for a biochemical reaction

Sparse and noisy measurements make parameter estimation for biochemical reaction networks difficult and might lead to ill-posed optimisation problems. This is potentiated if the data has to be normalised, and only fold changes rather than absolute amounts are available. Here, the authors consider the propagation of measurement noise to the distribution of the maximum likelihood (ML) estimator in an in silico study. Therefore, a model of a reversible reaction is considered, for which reaction rate constants using fold changes is estimated. Noise propagation is analysed for different normalisation strategies and different error models. In particular, accuracy, precision, and asymptotic properties of the ML estimator is investigated. Results show that normalisation by the mean of a time series outperforms normalisation by a single time point in the example provided by the authors. Moreover, the error model with a heavy-tail distribution is slightly more robust to large measurement noise, but, beyond this, the choice of the error model did not have a significant impact on the estimation results provided by the authors.

Lacticaseibacillus rhamnosus R0011 secretome attenuates Salmonella enterica serovar Typhimurium secretome-induced intestinal epithelial cell monolayer damage and pro-inflammatory mediator production in intestinal epithelial cell and antigen-presenting cell co-cultures

Certain lactic acid bacteria (LAB) are associated with immune modulatory activities including down-regulation of pro-inflammatory gene transcription and expression. While host antigen-presenting cells (APCs) and intestinal epithelial cells (IEC) can interact directly with both pathogenic and commensal bacteria through innate immune pattern recognition receptors, recent evidence indicates indirect communication through secreted molecules is an important inter-domain communication mechanism. This communication route may be especially important in the context of IEC and APC interactions which shape host immune responses within the gut environment. We have previously shown that the Lacticaseibacillus rhamnosus R0011 secretome (LrS) dampens pro-inflammatory gene transcription and mediator production from Tumor Necrosis Factor-α and Salmonella enterica serovar Typhimurium secretome (STS)-challenged HT-29 IECs through the induction of negative regulators of innate immunity. However, many questions remain about interactions mediated through these bacterial-derived soluble components and the resulting host immune outcomes in the context of IEC and APC interactions. In the present study, we examined the ability of the LrS to down-regulate pro-inflammatory gene transcription and cytokine production from STS-challenged T84 human IEC and THP-1 human monocyte co-cultures. Cytokine and chemokine profiling revealed that apically delivered LrS induces apical secretion of macrophage inhibitory factor (MIF) and down-regulates STS-induced pro-inflammatory mediator secretion into the apical and basolateral chambers of the T84/THP-1 co-culture. Transcriptional profiling confirmed these results, as the LrS attenuated STS challenge-induced CXCL8 and NFκB1 expression in T84 IECs and THP-1 APCs. Interestingly, the LrS also reversed STS-induced damage to monolayer transepithelial resistance (TER) and permeability, results which were confirmed by ZO-1 gene expression and immunofluorescence visualization of ZO-1 expression in T84 IEC monolayers. The addition of a MIF-neutralizing antibody abrogated the ability of the LrS to reverse STS-induced damage to T84 IEC monolayer integrity, suggesting a novel role for MIF in maintaining IEC barrier function and integrity in response to soluble components derived from LAB. The results presented here provide mechanistic evidence for indirect communication mechanisms used by LAB to modulate immune responses to pathogen challenge, using in vitro approaches which allow for IEC and APC cell communication in a context which more closely mimics that which occurs in vivo.

Butyrate Glycerides Protect against Intestinal Inflammation and Barrier Dysfunction in Mice

This study investigates the attenuating effects of butyrate glycerides (BG) on intestinal inflammatory responses and barrier dysfunction induced by LPS stimulation. An initial dose-response test was carried out to identify the optimal dose of BG for further testing. The mice were given intragastric administration of BG at different doses followed by lipopolysaccharide (LPS) intraperitoneal injection. The small intestinal morphology and cytokine mRNA expression were measured. With 1.5 g/kg BW BG administration, it was possible to alleviate the injury of duodenal morphology, attenuate ileum villus height reduction and promote IL-10 mRNA expression. Therefore, the optimal dosage of 1.5 g/kg BW BG was selected for the main experiment. The ultrastructure image of jejunum and ileum epithelial cells, mRNA expression, the level of cytokine and immunofluorescence in the ileum were analyzed. The results showed that BG maintain the ileac brush border, tight junction structures and protein expression. BG attenuated the increased inflammatory cytokines, TLR4 and JNK mRNA expression. Taken together, 1.5 g/kg BW BG administration maintained intestinal barrier function and reduced intestinal and body inflammation responses induced by LPS in mice. The mechanism by which BG alleviated intestinal inflammatory response and maintained intestinal barrier function may be related to the JNK signaling pathway.

Cyclooxygenase-2 deficiency attenuates lipopolysaccharide-induced inflammation, apoptosis, and acute lung injury in adult mice

Many lung diseases are caused by an excessive inflammatory response, and inflammatory lung diseases are often modeled using lipopolysaccharide (LPS) in mice. Cyclooxygenase-2 (COX-2) encoded by the Ptgs2 gene is induced in response to inflammatory stimuli including LPS. The objective of this study was to test the hypothesis that mice deficient in COX-2 (Ptgs2-/-) will be protected from LPS-induced lung injury. Wild-type (WT; CD1 mice) and Ptgs2-/- mice (on a CD1 background) were treated with LPS or vehicle for 24 h. LPS treatment resulted in histological evidence of lung injury, which was attenuated in the Ptgs2-/- mice. LPS treatment increased the mRNA levels for tumor necrosis factor-α, interleukin-10, and monocyte chemoattractant protein-1 in the lungs of WT mice, and the LPS-induced increases in these levels were attenuated in the Ptgs2-/- mice. The protein levels of active caspase-3 and caspase-9 were lower in the LPS-treated lungs of Ptgs2-/- mice than in LPS-treated WT mice, as were the number of terminal deoxynucleotide transferase dUTP nick end labeling-positive cells in lung sections. LPS exposure resulted in a greater lung wet-to-dry weight ratio (W/D) in WT mice, suggestive of pulmonary edema, while in LPS-treated Ptgs2-/- mice, the W/D was not different from controls and less than in LPS-treated WT mice. These results demonstrate that COX-2 is involved in the inflammatory response to LPS and suggest that COX-2 not only acts as a downstream participant in the inflammatory response, but also acts as a regulator of the inflammatory response likely through a feed-forward mechanism following LPS stimulation.

Lipidomic Profiling of Human Milk Derived Exosomes and Their Emerging Roles in the Prevention of Necrotizing Enterocolitis

SCOPE

Human milk can prevent the development of necrotizing enterocolitis (NEC). Human milk is rich in cargo-carrying exosomes that participate in intercellular communication. This study investigated the effects of term and preterm human milk-derived exosomes, and elucidated their lipid expression profiles.

METHODS AND RESULTS

Milk from healthy mothers is collected who have delivered full-term or preterm infants, and exosomes are isolated and quantified. Administration of term and preterm milk exosomes significantly enhances epithelial proliferation and migration in vitro, and ameliorates the severity of NEC in vivo. A total of 395 lipids are identified in term and preterm human milk-derived exosomes. Bioinformatics analysis and western blotting reveal that top 50 lipids regulate intestinal epithelial cell function via the Extracellular-Signal-Regulated Kinase/Mitogen Activated Protein Kinase (ERK/MAPK) pathway.

CONCLUSION

This study reveals for the first time the lipidomic complexities in exosomes derived from preterm and term milk. The results provide novel mechanistic insight on how human milk prevents the development of NEC.

Single nucleotide polymorphisms in the dual specificity phosphatase genes and risk of necrotizing enterocolitis in premature infant

BACKGROUND

Differences in the susceptibility of preterm infants to develop necrotizing enterocolitis (NEC) implicate potential genetic differences in response to the inflammatory stimuli leading to NEC. Dual specificity phosphatases (DUSPs) are a key suppressor pathway of the mitogen-activated protein kinase (MAPK) pro-inflammatory signaling pathway. We hypothesized that inherited single nucleotide polymorphisms (SNPs) in DUSP genes contribute to NEC susceptibility in premature infants.

METHODS

Patients admitted between 2010 and 2015 born at <  32 weeks GA and≤1,500 g BW with stage II+NEC (cases; n = 50) and age, weight-matched controls (n = 38) were included. Blood samples were collected for DNA isolation. Agena Mass Array assay was used to examine 31 SNPs in 9 different DUSP genes. Calculated minor allele frequencies (MAF) for cases and controls were compared using χ2 and logistic regression.

RESULTS

The presence of the rs704074 SNP was associated with a 48% decreased risk of developing NEC (OR 0.52; 95% CI 0.27- 1.01, p = 0.04). The odds of surgical NEC decreased by 78% (OR 0.22; 95% CI 0.06- 0.84, p = 0.027) for each copy of rs704074/G allele in patients with NEC.

CONCLUSION

In this small single-center pilot study, DUSP-6 SNP (rs704074) was associated with a lower risk of developing NEC and surgical NEC, the most severe form of NEC, in preterm infants.

Dual-specificity phosphatase (DUSP) genetic variants predict pulmonary hypertension in patients with bronchopulmonary dysplasia

BACKGROUND

Pulmonary hypertension (PH) in patients with bronchopulmonary dysplasia (BPD) results from vasoconstriction and/or vascular remodeling, which can be regulated by mitogen-activated protein kinases (MAPKs). MAPKs are deactivated by dual-specificity phosphatases (DUSPs). We hypothesized that single-nucleotide polymorphisms (SNPs) in DUSP genes could be used to predict PH in BPD.

METHODS

Preterm infants diagnosed with BPD (n = 188) were studied. PH was defined by echocardiographic criteria. Genomic DNA isolated from patient blood samples was analyzed for 31 SNPs in DUSP genes. Clinical characteristics and minor allele frequencies were compared between BPD-PH (cases) and BPD-without PH (control) groups. Biomarker models to predict PH in BPD using clinical and SNP data were tested by calculations of area under the ROC curve.

RESULTS

In our BPD cohort, 32% (n = 61) had PH. Of the DUSP SNPs evaluated, DUSP1 SNP rs322351 was less common, and DUSP5 SNPs rs1042606 and rs3793892 were more common in cases than in controls. The best fit biomarker model combines clinical and DUSP genetic data with an area under the ROC curve of 0.76.

CONCLUSION

We identified three DUSP SNPs as potential BPD-PH biomarkers. Combining clinical and DUSP genetic data yields the most robust predictor for PH in BPD.

Antifibrotic effects of Fraxetin on carbon tetrachloride-induced liver fibrosis by targeting NF-κB/IκBα, MAPKs and Bcl-2/Bax pathways

BACKGROUND

Liver fibrosis is a chronic lesion which ultimately results in cirrhosis and possible death. Although the high incidence and lethality, few therapies are effective for liver fibrosis. Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a natural product extracted from cortex fraxini, has exhibited a significant hepatoprotective and anti-fibrotic properties. However, the underlying mechanism of the anti-hepatic fibrotic property remains unknown.

METHODS

48 Male Sprague Dawley rats were divided into four groups at random which were named as normal group, model group, fraxetin 25 mg/kg and 50 mg/kg group. The experimental model of liver fibrosis was founded by carbon tetrachloride (CCl₄) rats which were simultaneously treated with fraxetin (25 mg/kg or 50 mg/kg). Normal groups received equal volumes of saline and peanut oil.

RESULTS

Results showed that fraxetin ameliorated CCl₄ induced liver damage and fibrosis. Furthermore, histopathology examinations revealed that fraxetin improved the morphology and alleviated collagen deposition in fibrotic liver. Fraxetin inhibited inflammation and hepatocytes apoptosis by modulating the NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways.

CONCLUSION

Our findings indicate that fraxetin is effective in preventing liver fibrosis through inhibiting inflammation and hepatocytes apoptosis which is associated with regulating NF-κB/IκBα, MAPKs and Bcl-2/Bax signaling pathways in rats.

Surfactant Proteins-A and -D Attenuate LPS-Induced Apoptosis in Primary Intestinal Epithelial Cells (IECs)

INTRODUCTION

SP-A/D KO mice with sepsis demonstrate more severe lung, kidney, and gut injury/apoptosis than WT controls. We hypothesize SP-A and SP-D directly regulate lipopolysaccharide (LPS)-induced P38 mitogen-activated protein kinase (MAPK) activation and gut apoptosis during sepsis.

METHODS

Primary IECs were established from SP-A/D KO or C57BL/6 WT mice, stimulated with LPS and harvested at 24 h. IECs from WT mice were treated with SP-A, SP-D, or vehicle for 20 h, then LPS for 24 h. Apoptosis, cleaved caspase-3 levels and the ratio of BAX/Bcl-2 were assayed. The role of P38 MAPK was examined using the P38 MAPK-agonist U46619 and inhibitor SB203580 in LPS-treated cells. p-P38 MAPK/t-P38 MAPK, TLR4, and CD14 were measured by Western Blot.

RESULTS

LPS-induced apoptosis, caspase-3 levels, BAX/Bcl-2, and p-P38/t-P38 MAPK were increased in SP-A/D KO IECs. SP-A and SP-D attenuate LPS-induced increase in apoptosis, cleaved caspase-3, BAX/Bcl-2, and p-P38/t-P38 MAPK in WT IECs. U46619 increased apoptosis, caspase-3, and BAX/Bcl-2 in IECs which was attenuated by SP-A/D. SB203580 attenuates the LPS-induced increase in apoptosis, caspase-3, and BAX/Bcl-2 in WT IECs. Addition of SP-A or SP-D to SB203580 completely ameliorates LPS-induced apoptosis. The LPS-induced increase in TLR4 and CD14 expression is greater in IECs from SP-A/D KO mice and treatment of WT IECs with SP-A or SP-D prevents the LPS-induced increase in TLR4 and CD14.

CONCLUSIONS

SP-A and SP-D attenuate LPS-induced increases in apoptosis, caspase-3, and BAX/Bcl-2 in IECs. Attenuation of LPS-induced activation of TLR4 and P38 MAPK signaling pathways represents potential mechanisms for the protective effects of SP-A/D on apoptosis.

Epidermal Growth Factor, through Alleviating Oxidative Stress, Protect IPEC-J2 Cells from Lipopolysaccharides-Induced Apoptosis

The epidermal growth factor (EGF) has been widely used for protection of stress-induced intestinal mucosa dysfunction. However, whether EGF would alleviate oxidative injury and reduce apoptosis in porcine intestine is not yet known. Therefore, the aim of this study was to investigate the effect of EGF on lipopolysaccharides (LPS)-induced induction of oxidative stress and ensuing apoptosis in the porcine intestinal epithelial cell line, IPEC-J2. The present study showed that EGF significantly increased cell viability and decreased the LPS-induced induction of apoptosis, dehydrogenase (LDH) release and malonaldehyde (MDA) production. EGF also (i) decreased expression of the pro-apoptotic genes Fas, Bax, Cascase-3, Cascase-8, Cascase-9, and proteins such as P53, Fas, Bax, Caspase3; (ii) increased antiapoptotic protein B-cell lymphoma 2 (Bcl2) expression; (iii) increased mRNA levels of the nuclear factor erythroid 2-related factor 2 (Nrf2) related genes Nrf2, manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GSH-Px), heme oxygenase (HO-1) and quinone oxidoreductase (NQO1); (iv) protein level of Nrf2-realeted proteins Nrf2, HO-1, NQO1; and (v) total antioxidant capacity (T-AOC), CAT, SOD, GSH-Px concentrations. Collectively, our results indicated that EGF enhanced Nrf2 protein expression, and upregulated the expression of phase II metabolizing enzymes (such as HO-1 and NQO1) and antioxidative enzymes (SOD, CAT and GSH-Px) to alleviate oxidative injury, and then protect IPEC-J2 cells from apoptosis induced by LPS.

Exposure to Anisakis extracts can induce inflammation on in vitro cultured human colonic cells

Anisakis spp. is a parasitic nematode whose infective third-stage larvae may be found within the flesh of fish species commonly consumed by humans. Thorough cooking or freezing should render the fish safe for consumption; furthermore, marinating solutions containing biocidal agents might have a significant action against Anisakis larvae. Some studies suggest a relationship between some parasitic infections and development of inflammatory bowel disorders, and Anisakis infection might be a risk factor for stomach or colon cancer. The aim of our study was to investigate if crude extracts (CEs) obtained from Anisakis larvae marinated in a solution with added allyl isothiocyanate (ACE-AITC) and frozen, or from frozen only Anisakis larvae (ACE), can induce an inflammatory effect on in vitro differentiated colonic Caco-2 cells exposed or not to LPS. Caco-2 exposure to the two CEs induced a marked COX-2 expression and potentiated LPS-induced COX-2 overexpression, confirming that substances present in Anisakis larvae can induce an inflammatory response in the intestinal epithelium, possibly also exacerbating the effects of other inflammatory stimuli. ACE induced a marked decrease in caspase-3 activation, while AITC-ACE increased its activation. However, LPS-induced caspase-3 activation appeared lower in cells treated with ACE and with the lower concentration of AITC-ACE. Thus, it is evident that Anisakis CEs may affect various cell pathways crucial not only in the inflammatory process but also in cell growth and death. Thus, CEs obtained from nonviable Anisakis larvae retain or are otherwise provided with noxious properties able to induce a strong inflammation response in intestinal epithelial cells. Furthermore, their influence may persist also following pretreatment with the biocidal agent AITC, indicating that the harmful substances contained in crude extracts from Anisakis larvae are resistant to the thermal or biocidal agent treatments.

Immunostimulated Arginase II Expression in Intestinal Epithelial Cells Reduces Nitric Oxide Production and Apoptosis

Increased production of nitric oxide (NO) and subsequent local cytotoxicity to mucosal epithelial cells has been proposed as a putative mechanism involved in the development of necrotizing enterocolitis (NEC). Intestinal epithelial cells (IECs) metabolize L-arginine to either nitric oxide (NO) by NO synthase (NOS) or to L-ornithine and urea by arginase. L-ornithine is the first step in polyamine synthesis important for cell proliferation, while NO production can lead to apoptosis. We hypothesized that in IECs immunostimulation increases both NOS and arginase expression, and that arginase activity mitigates NO production and apoptosis. Rat intestinal epithelial cells (rIEC-6) were immunostimulated by either incubation with lipopolysaccharide (LPS) alone for 24 h or by incubation with conditioned media (CM) for 24 h. CM was obtained from RAW 264.7 cells (a macrophage cell line) treated with LPS (E. coli 0127:B8; 1 μg/ml) for 4 h. The rIEC-6 stimulated with LPS or with CM had significantly higher levels of inducible NOS (iNOS) protein, NO production, and arginase II protein than did the control cells. Direct LPS stimulation of rIEC-6 produced a less robust increase in iNOS expression and NO (represented as nitrite percent of control) than did CM stimulation. Inhibition of arginase using N^ω hydroxyl-L-arginine (NOHA) further increased stimulated NO production in rIEC-6. Viable cell numbers were significantly lower in CM stimulated cells after 24 h than in controls, and inhibition of arginase activity with NOHA resulted in a further significant decrease in viable cell numbers. We conclude that immunostimulated arginase expression of rIEC-6 cells tempers cytokine-induced iNOS-derived NO production and apoptosis.