Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte

Targeting transcription factors for therapeutic benefit in rheumatoid arthritis

Rheumatoid arthritis (RA) is a destructive inflammatory autoimmune disease that causes pain and disability. Many of the currently available drugs for treating RA patients are aimed at halting the progression of the disease and alleviating inflammation. Further, some of these treatment options have drawbacks, including disease recurrence and adverse effects due to long-term use. These inefficiencies have created a need for a different approach to treating RA. Recently, the focus has shifted to direct targeting of transcription factors (TFs), as they play a vital role in the pathogenesis of RA, activating key cytokines, chemokines, adhesion molecules, and enzymes. In light of this, synthetic drugs and natural compounds are being explored to target key TFs or their signaling pathways in RA. This review discusses the role of four key TFs in inflammation, namely NF-κB, STATs, AP-1 and IRFs, and their potential for being targeted to treat RA.

Aging-induced isoDGR-modified fibronectin activates monocytic and endothelial cells to promote atherosclerosis

BACKGROUND AND AIMS

Aging is the primary risk factor for cardiovascular disease (CVD), but the mechanisms underlying age-linked atherosclerosis remain unclear. We previously observed that long-lived vascular matrix proteins can acquire 'gain-of-function' isoDGR motifs that might play a role in atherosclerotic pathology.

METHODS

IsoDGR-specific mAb were generated and used for ELISA-based measurement of motif levels in plasma samples from patients with coronary artery diseases (CAD) and non-CAD controls. Functional consequences of isoDGR accumulation in age-damaged fibronectin were determined by bioassay for capacity to activate monocytes, macrophages, and endothelial cells (signalling activity, pro-inflammatory cytokine expression, and recruitment/adhesion potential). Mice deficient in the isoDGR repair enzyme PCMT1 were used to assess motif distribution and macrophage localisation in vivo.

RESULTS

IsoDGR-modified fibronectin and fibrinogen levels in patient plasma were significantly enhanced in CAD and further associated with smoking status. Functional assays demonstrated that isoDGR-modified fibronectin activated both monocytes and macrophages via integrin receptor 'outside in' signalling, triggering an ERK:AP-1 cascade and expression of pro-inflammatory cytokines MCP-1 and TNFα to drive additional recruitment of circulating leukocytes. IsoDGR-modified fibronectin also induced endothelial cell expression of integrin β1 to further enhance cellular adhesion and matrix deposition. Analysis of murine aortic tissues confirmed accumulation of isoDGR-modified proteins co-localised with CD68+ macrophages in vivo.

CONCLUSIONS

Age-damaged fibronectin features isoDGR motifs that increase binding to integrins on the surface of monocytes, macrophages, and endothelial cells. Subsequent activation of 'outside-in' signalling elicits a range of potent cytokines and chemokines that drive additional leukocyte recruitment to the developing atherosclerotic matrix.

Mutant glucocorticoid receptor binding elements on the interleukin-6 promoter regulate dexamethasone effects

Background

Glucocorticoids (GCs) have been extensively used as essential modulators in clinical infectious and inflammatory diseases. The GC receptor (GR) is a transcription factor belonging to the nuclear receptor family that regulates anti-inflammatory processes and releases pro-inflammatory cytokines, such as interleukin (IL)-6.

Results

Five putative GR binding sites and other transcriptional factor binding sites were identified on theIL-6 promoter, and dexamethasone (DEX) was noted to reduce the lipopolysaccharide (LPS)-induced IL-6 production. Among mutant transcriptional factor binding sites, nuclear factor-kappa B (NF-κB), activator protein (AP)-1, and specificity protein (Sp)1–2 sites reduced basal and LPS-induced IL-6 promoter activities through various responses. The second GR binding site (GR2) was noted to play a crucial role in both basal and inducible promoter activities in LPS-induced inflammation.

Conclusions

We concluded that selective GR2 modulator might exert agonistic and antagonistic effects and could activate crucial signaling pathways during the LPS-stimulated inflammatory process.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00413-z.

Indole-3-lactic acid, a metabolite of tryptophan, secreted by Bifidobacterium longum subspecies infantis is anti-inflammatory in the immature intestine

BACKGROUND

Necrotizing enterocolitis (NEC), a necrotic inflammation of the intestine, represents a major health problem in the very premature infant. Although prevention is difficult, the combination of ingestion of maternal-expressed breastmilk in conjunction with a probiotic provides the best protection. In this study, we establish a mechanism for breastmilk/probiotic protection.

METHODS

Ultra-high-performance liquid chromatography-tandem mass spectrometry of Bifidobacterium longum subsp. infantis (B. infantis) secretions was used to identify an anti-inflammatory molecule. Indole-3-lactic acid (ILA) was then tested in an established human immature small intestinal cell line, necrotizing colitis enterocytes, and other immature human enteroids for anti-inflammatory effects and to establish developmental function. ILA was also examined in immature and mature enterocytes.

RESULTS

We have identified ILA, a metabolite of breastmilk tryptophan, as the anti-inflammatory molecule. This molecule is developmentally functional in immature but not mature intestinal enterocytes; ILA reduces the interleukin-8 (IL-8) response after IL-1β stimulus. It interacts with the transcription factor aryl hydrocarbon receptor (AHR) and prevents transcription of the inflammatory cytokine IL-8.

CONCLUSIONS

This molecule produced by B. infantis (ATCC No. 15697) interaction with ingested breastmilk functions in a complementary manner and could become useful in the treatment of all at-risk premature infants for NEC if safety and clinical studies are performed.

The developmentally regulated fetal enterocyte gene, ZP4, mediates anti-inflammation by the symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis

Initial colonizing bacteria play a critical role in completing the development of the immune system in the gastrointestinal tract of infants. Yet, the interaction of colonizing bacterial organisms with the developing human intestine favors inflammation over immune homeostasis. This characteristic of bacterial-intestinal interaction partially contributes to the pathogenesis of necrotizing enterocolitis (NEC), a devastating premature infant intestinal inflammatory disease. However, paradoxically some unique pioneer bacteria (initial colonizing species) have been shown to have a beneficial effect on the homeostasis of the immature intestine and the prevention of inflammation. We have reported that one such pioneer bacterium, Bacteroides fragilis (B. fragilis), and its surface component polysaccharide A (PSA) inhibit IL-1β-induced inflammation in a human primary fetal small intestinal cell line (H4 cells). In this study, using transcription profiling of H4 cellular RNA after pretreatment with or without PSA before an inflammatory stimulation of IL-1β, we have begun to further determine the cellular mechanism for anti-inflammation. We show that a developmentally regulated gene, zona pellucida protein 4 (ZP4), is uniquely elevated after IL-1β stimulation and reduced with PSA exposure. ZP4 was known as a sperm receptor-mediating species-specific binding protein in the initial life of mammals. However, its intestinal epithelial function is unclear. We found that ZP4 is a developmentally regulated gene involved with immune function and regulated by both Toll-like receptor 2 and 4. Knockdown of ZP4-affected PSA inhibited IL-8 mRNA expression in response to IL-1β. This represents an initial study of ZP4 innate immune function in immature enterocytes. This study may lead to new opportunity for efficient treatment of NEC.NEW & NOTEWORTHY This study extends previous observations to define the cellular mechanisms of polysaccharide A-induced anti-inflammation in immature enterocytes using transcription profiling of enterocyte genes after preexposure to polysaccharide A before an inflammatory stimulus with IL-1β.

Curcumin and Intestinal Inflammatory Diseases: Molecular Mechanisms of Protection

Intestinal inflammatory diseases, such as Crohn’s disease, ulcerative colitis, and necrotizing enterocolitis, are becoming increasingly prevalent. While knowledge of the pathogenesis of these related diseases is currently incomplete, each of these conditions is thought to involve a dysfunctional, or overstated, host immunological response to both bacteria and dietary antigens, resulting in unchecked intestinal inflammation and, often, alterations in the intestinal microbiome. This inflammation can result in an impaired intestinal barrier allowing for bacterial translocation, potentially resulting in systemic inflammation and, in severe cases, sepsis. Chronic inflammation of this nature, in the case of inflammatory bowel disease, can even spur cancer growth in the longer-term. Recent research has indicated certain natural products with anti-inflammatory properties, such as curcumin, can help tame the inflammation involved in intestinal inflammatory diseases, thus improving intestinal barrier function, and potentially, clinical outcomes. In this review, we explore the potential therapeutic properties of curcumin on intestinal inflammatory diseases, including its antimicrobial and immunomodulatory properties, as well as its potential to alter the intestinal microbiome. Curcumin may play a significant role in intestinal inflammatory disease treatment in the future, particularly as an adjuvant therapy.

Pathophysiology of Necrotizing Enterocolitis: An Update

NEC is a devastating disease that, once present, is very difficult to treat. In the absence of an etiologic treatment, preventive measures are required. Advances in decoding the pathophysiology of NEC are being made but a more comprehensive understanding is needed for the targeting of preventative strategies. A better definition of the disease as well as diagnostic criteria are needed to be able to specifically label a disease as NEC. Multiple environmental factors combined with host susceptibility appear to contribute to enhanced risks for developing this disease. Several different proximal pathways are involved, all leading to a common undesired outcome: Intestinal necrosis. The most common form of this disease appears to involve inflammatory pathways that are closely meshed with the intestinal microbiota, where a dysbiosis may result in dysregulated inflammation. The organisms present in the intestinal tract prior to the onset of NEC along with their diversity and functional capabilities are just beginning to be understood. Fulfillment of postulates that support causality for particular microorganisms is needed if bacteriotherapies are to be intelligently applied for the prevention of NEC. Identification of molecular effector pathways that propagate inflammation, understanding of, even incipient role of genetic predisposition and of miRNAs may help solve the puzzle of this disease and may bring the researchers closer to finding a treatment. Despite recent progress, multiple limitations of the current animal models, difficulties related to studies in humans, along with the lack of a "clear" definition will continue to make it a very challenging disease to decipher.

Ginger (Zingiber officinale Roscoe) for the treatment and prevention of necrotizing enterocolitis

ETHNOPHARMACOLOGICAL RELEVANCE

Necrotizing enterocolitis (NEC) is the most important gastrointestinal emergency affecting especially preterm infants and causes severe morbidities and mortality. However, there is no cure. Oxidant stress, inflammation, apoptosis, as well as prematurity are believed to responsible in the pathogenesis of the disease. Ginger and its compounds have anti-inflammatory, antimicrobial, anti-oxidant properties and immunomodulatory, cytoprotective/regenerative actions.

AIM OF THE STUDY

This study aimed to evaluate the beneficial effects of ginger on the intestinal damage in an experimental rat model of NEC.

MATERIALS AND METHODS

Thirty newborn Wistar rats were divided into three groups: NEC, NEC + ginger and control in this experimental study. NEC was induced by injection of intraperitoneal lipopolysaccharide, feeding with enteral formula, hypoxia-hyperoxia and cold stress exposure. The pups in the NEC + ginger group were orally administered ginger at a dose of 1000 mg/kg/day. Proximal colon and ileum were excised. Histopathological, immunohistochemical (TUNEL for apoptosis, caspase 3 and 8) and biochemical assays including xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malonaldehyde (MDA) and myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α), interleukin1β (IL-1β), and interleukin 6 (IL-6) activity were evaluated.

RESULTS

Compared with the NEC group, the rat pups in the NEC + ginger group had better clinical disease scores and weight gain (p < 0.05). Macroscopic evaluation, Histopathologic and apoptosis assessment (TUNEL, caspase 3 and 8) releaved that severity of intestinal damage were significantly lower in the NEC + ginger group (p < 0.05). The levels of TNF-α, IL-1β and IL-6 in the ginger treated group were significantly decreased (P < 0.05). The GSH-Px and SOD levels of the ginger treated group were significantly preserved in the NEC + ginger group (p < 0.05). The tissue XO, MDA and MPO levels of the NEC + ginger group were significantly lower than those in the NEC group (P < 0.05).

CONCLUSION

Ginger therapy efficiently ameliorated the severity of intestinal damage in NEC and may be a promising treatment option.

Human Fetal-Derived Enterospheres Provide Insights on Intestinal Development and a Novel Model to Study Necrotizing Enterocolitis (NEC)

BACKGROUND & AIMS

Untreated necrotizing enterocolitis (NEC) can lead to massive inflammation resulting in intestinal necrosis with a high mortality rate in preterm infants. Limited access to human samples and relevant experimental models have hampered progress in NEC pathogenesis. Earlier evidence has suggested that bacterial colonization of an immature and developing intestine can lead to an abnormally high inflammatory response to bacterial bioproducts. The aim of our study was to use human fetal organoids to gain insights into NEC pathogenesis.

METHODS

RNA sequencing analysis was performed to compare patterns of gene expression in human fetal-derived enterospheres (FEnS) and adult-derived enterospheres (AEnS). Differentially expressed genes were analyzed using computational techniques for dimensional reduction, clustering, and gene set enrichment. Unsupervised cluster analysis, Gene Ontology, and gene pathway analysis were used to predict differences between gene expression of samples. Cell monolayers derived from FEnS and AEnS were evaluated for epithelium function and responsiveness to lipopolysaccharide and commensal bacteria.

RESULTS

Based on gene expression patterns, FEnS clustered according to their developmental age in 2 distinct groups: early and late FEnS, with the latter more closely resembling AEnS. Genes involved in maturation, gut barrier function, and innate immunity were responsible for these differences. FEnS-derived monolayers exposed to either lipopolysaccharide or commensal Escherichia coli showed that late FEnS activated gene expression of key inflammatory cytokines, whereas early FEnS monolayers did not, owing to decreased expression of nuclear factor-κB-associated machinery.

CONCLUSIONS

Our results provide insights into processes underlying human intestinal development and support the use of FEnS as a relevant human preclinical model for NEC. Accession number of repository for expression data: GSE101531.

Significance of dynamic evolution of TNF-α, IL-6 and intestinal fatty acid-binding protein levels in neonatal necrotizing enterocolitis

To study the significance of dynamic evolution of serum tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) and intestinal fatty acid-binding protein (I-FABP) levels in neonatal necrotizing enterocolitis (NEC). A total of 45 NEC child patients, 45 non-NEC child patients and 45 healthy newborns were enrolled. After the day age, weight, gestational week and delivery mode were matched, the serum TNF-α, IL-6 and I-FABP levels at 6, 24 and 72 h after admission were measured via ELISA method, and their correlations with prognosis were analyzed. The levels of serum TNF-α and IL-6 in NEC and non-NEC group reached the peak at 24 h and fell at 72 h; there were no differences in each time point between the two groups (P>0.05), but the levels of serum TNF-α and IL-6 were higher than those in the control group (P<0.05). The level of serum I-FABP in NEC and non-NEC group reached the peak at 6 h, and it fell at 72 h in NEC group and 24 h in non-NEC group; the level of I-FABP in each time point in NEC was significantly higher than that in non-NEC group, and the level was the lowest in healthy group; the differences were statistically significant (P<0.05). There were 40 cases of survival and 5 cases of death (11.1%) in NEC group, while there were 43 cases of survival and 2 cases of death (4.4%) in non-NEC group. There were no differences in serum TNF-α and IL-6 levels at different times between surviving child patients and dead child patients in NEC group (P>0.05), but the levels of serum I-FABP in surviving child patients at 6 h and 24 h were significantly lower than those in dead child patients (P<0.05), and there was no difference at 72 h (P>0.05). There were no differences in serum TNF-α, IL-6 and I-FABP levels at different times between surviving and dead child patients in non-NEC group (P>0.05). Serum I-FABP level and its dynamic evolution may be important indexes of early diagnosis and prognosis evaluation of NEC.

Hypoxia induced mitogenic factor (HIMF) triggers angiogenesis by increasing interleukin-18 production in myoblasts

Inflammatory myopathy is a rare autoimmune muscle disorder. Treatment typically focuses on skeletal muscle weakness or inflammation within muscle, as well as complications of respiratory failure secondary to respiratory muscle weakness. Impaired respiratory muscle function contributes to increased dyspnea and reduced exercise capacity in pulmonary hypertension (PH), a debilitating condition that has few treatment options. The initiation and progression of PH is associated with inflammation and inflammatory cell recruitment and it is established that hypoxia-induced mitogenic factor (HIMF, also known as resistin-like molecule α), activates macrophages in PH. However, the relationship between HIMF and inflammatory myoblasts remains unclear. This study investigated the signaling pathway involved in interleukin-18 (IL-18) expression and its relationship with HIMF in cultured myoblasts. We found that HIMF increased IL-18 production in myoblasts and that secreted IL-18 promoted tube formation of the endothelial progenitor cells. We used the mouse xenograft model and the chick chorioallantoic membrane assay to further explore the role of HIMF in inflammatory myoblasts and angiogenesis in vivo. Thus, our study focused on the mechanism by which HIMF mediates IL-18 expression in myoblasts through angiogenesis in vitro and in vivo. Our findings provide an insight into HIMF functioning in inflammatory myoblasts.

Inhibition of Endoplasmic Reticulum Stress Alleviates Lung Injury Induced by Brain Death

Brain death (BD) can induce inflammation and injury of organs. Endoplasmic reticulum (ER) stress is associated with a variety of diseases. However, little is known about how ER stress is implicated in brain death (BD)-induced lung injury. In this study, a stable BD rat model was constructed to investigate the role of ER stress on BD-induced lung injury. H&E staining demonstrated that BD can induce lung injury in rats. The results of Western blot and immunohistochemistry showed that apoptosis was observed in the lung tissues of BD rats. And the level of GRP78, p-PERK, p-eIF2α, CHOP, and Caspase-12 was highly expressed in BD rats compared with the control group. Inhibition of ER stress with salubrinal reduced the BD-induced lung inflammation. Moreover, BD-induced increase of NF-κB activity was lowered by inhibition of ER stress. These results suggested that inhibition of ER stress alleviates BD-induced lung inflammation by regulating NF-κB signaling pathway.

The symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis inhibits IL-1β-induced inflammation in human fetal enterocytes via toll receptors 2 and 4

Colonizing bacteria interacting with the immature, unlike the mature, human intestine favors inflammation over immune homeostasis. As a result, ten percent of premature infants under 1500 grams weight develop an inflammatory necrosis of the intestine after birth, e.g., necrotizing enterocolitis (NEC). NEC is a major health problem in this population causing extensive morbidity and mortality and an enormous expenditure of health care dollars. NEC can be prevented by giving preterm infants their mother’s expressed breast milk or ingesting selective probiotic organisms. Vaginally delivered, breast fed newborns develop health promoting bacteria (“pioneer” bacteria) which preferentially stimulate intestinal host defense and anti-inflammation. One such “pioneer” organism is Bacteroides fragilis with a polysaccharide (PSA) on its capsule. B. fragilis has been shown developmentally in intestinal lymphocytes and dendritic cells to produce a balanced T-helper cell (TH1/TH2) response and to reduce intestinal inflammation by activity through the TLR2 receptor stimulating IL-10 which inhibits IL-17 causing inflammation. No studies have been done on the role of B. fragilis PSA on fetal enterocytes and its increased inflammation. Accordingly, using human and mouse fetal intestinal models, we have shown that B. fragilis with PSA and PSA alone inhibits IL-1β-induced IL-8 inflammation in fetal and NEC intestine. We have also begun to define the mechanism for this unique inflammation noted in fetal intestine. We have shown that B. fragilis PSA anti-inflammation requires both the TLR2 and TLR4 receptor and is in part mediated by the AP1 transcription factor (TLR2) which is developmentally regulated. These observations may help to devise future preventative treatments of premature infants against NEC.

Anti-inflammatory effects of Bifidobacterium longum subsp infantis secretions on fetal human enterocytes are mediated by TLR-4 receptors

The therapeutic and preventive application of probiotics for necrotizing enterocolitis (NEC) has been supported by more and more experimental and clinical evidence in which Toll-like receptor 4 (TLR-4) exerts a significant role. In immune cells, probiotics not only regulate the expression of TLR-4 but also use the TLR-4 to modulate the immune response. Probiotics may also use the TLR-4 in immature enterocytes for anti-inflammation. Here we demonstrate that probiotic conditioned media (PCM) from Bifidobacterium longum supp infantis but not isolated organisms attenuates interleukin-6 (IL-6) induction in response to IL-1β by using TLR-4 in a human fetal small intestinal epithelial cell line (H4 cells), human fetal small intestinal xenografts, mouse fetal small intestinal organ culture tissues, and primary NEC enterocytes. Furthermore, we show that PCM, using TLR-4, downregulates the mRNA expression of interleukin-1 receptor-associated kinase 2 (IRAK-2), a common adapter protein shared by IL-1β and TLR-4 signaling. PCM also reduces the phosphorylation of the activator-protein 1 (AP-1) transcription factors c-Jun and c-Fos in response to IL-1β stimulation in a TLR-4-dependent manner. This study suggests that PCM may use TLR-4 through IRAK-2 and via AP-1 to prevent IL-1β-induced IL-6 induction in immature enterocytes. Based on these observations, the combined use of probiotics and anti-TLR-4 therapy to prevent NEC may not be a good strategy.