Oral delivery of staphylococcal nuclease ameliorates DSS induced ulcerative colitis in mice via degrading intestinal neutrophil extracellular traps

Neutrophil extracellular traps induce barrier dysfunction in DSS-induced ulcerative colitis via the cGAS-STING pathway

Peptidyl arginine deiminase 4 (PAD4)-mediated neutrophil extracellular traps (NETs) play a crucial role in the pathogenesis of ulcerative colitis (UC). The cGAS-STING intracellular DNA-sensing pathway has been recognized as a pivotal mediator of inflammation. This study aimed to explore how NETs contribute to intestinal inflammation and barrier dysfunction in UC, focusing on the cGAS-STING pathway. We observed a significant increase of STING expression in UC mouse colons, which was mitigated by blocking NET formation through PAD4 genetic knockout. Moreover, NETs were discovered to activate the cGAS-STING pathway in MC38 cells in a dose and time-dependent manner, leading to the secretion of inflammatory cytokines and impaired barrier function. Additionally, STING deficiency ameliorated the clinical colitis index, intestinal inflammation, and barrier dysfunction. These findings underscore the involvement of cGAS-STING in regulating NET-mediated intestinal inflammation, suggesting its potential as a novel therapeutic target for UC.

Advances in carbohydrate-based nanoparticles for targeted therapy of inflammatory bowel diseases: A review

The incidence of inflammatory bowel disease (IBD), a chronic gastrointestinal disorder, is rapidly increasing worldwide. Unfortunately, the current therapies for IBD are often hindered by premature drug release and undesirable side effects. With the advancement of nanotechnology, the innovative targeted nanotherapeutics are explored to ensure the accurate delivery of drugs to specific sites in the colon, thereby reducing side effects and improving the efficacy of oral administration. The emphasis of this review is to summarize the potential pathogenesis of IBD and highlight recent breakthroughs in carbohydrate-based nanoparticles for IBD treatment, including their construction, release mechanism, potential targeting ability, and their therapeutic efficacy. Specifically, we summarize the latest knowledge regarding environmental-responsive nano-systems and active targeted nanoparticles. The environmental-responsive drug delivery systems crafted with carbohydrates or other biological macromolecules like chitosan and sodium alginate, exhibit a remarkable capacity to enhance the accumulation of therapeutic drugs in the inflamed regions of the digestive tract. Active targeting strategies improve the specificity and accuracy of oral drug delivery to the colon by modifying carbohydrates such as hyaluronic acid and mannose onto nanocarriers. Finally, we discuss the challenges and provide insight into the future perspectives of colon-targeted delivery systems for IBD treatment.

Effects of the N-Butanol Extract of Pulsatilla Decoction on Neutrophils in a Mouse Model of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory disease, the incidence of which is increasing worldwide. However, the etiology and pathogenesis of UC remains unclear. The n-butanol extract of Pulsatilla decoction (BEPD), a traditional Chinese medicine, has been shown to be effective in treating UC. This study aimed to explore the molecular mechanism underlying the effects of BEPD on UC, in particular its effects on neutrophil extracellular trap (NET) formation by neutrophils. High-performance liquid chromatography was used to determine the principal compounds of BEPD. UC was induced in mice using dextran sodium sulfate, and mice were treated with 20, 40, or 80 mg/kg BEPD daily for seven days. Colonic inflammation was determined by assessing the disease activity index, histopathology, colonic mucosal damage index, colonic mucosal permeability, and pro- and anti-inflammatory cytokine levels. The infiltration and activation status of neutrophils in the colon were determined by analyzing the levels of chemokine (C-X-C motif) ligand (CXCL) 1 and CXCL2, reactive oxygen species, Ly6G, and numerous NET proteins. The findings suggest that BEPD improved the disease activity index, histopathology, and colonic mucosal damage index scores of mice with UC, and restored colonic mucosal permeability compared with untreated mice. The expression levels of the pro-inflammatory cytokines interleukin-1β, interleukin-6, and tumor necrosis factor-α in colon tissues were significantly decreased, while the expression levels of anti-inflammatory cytokines in colon tissues were significantly increased, exceeding those of control mice. In addition, BEPD reduced the expression of the neutrophil chemokines CXCL1 and CXCL2 in the colon tissue of mice with UC, reduced neutrophil infiltration, reduced reactive oxygen species levels, and significantly reduced the expression of NET proteins. BEPD also significantly reduced NET formation. The results of this study suggest that BEPD exerts therapeutic effects in a murine model of UC by inhibiting neutrophil infiltration and activation in the colon, as well as by inhibiting the expression of key proteins involved in NET formation and reducing NET formation, thereby alleviating local tissue damage and disease manifestations.

The emerging role of neutrophil extracellular traps in ulcerative colitis

Ulcerative colitis (UC) is characterized by chronic non-recessive inflammation of the intestinal mucosa involving both innate and adaptive immune responses. Currently, new targeted therapies are urgently needed for UC, and neutrophil extracellular traps (NETs) are new therapeutic options. NETs are DNA-based networks released from neutrophils into the extracellular space after stimulation, in which a variety of granule proteins, proteolytic enzymes, antibacterial peptides, histones, and other network structures are embedded. With the deepening of the studies on NETs, their regulatory role in the development of autoimmune and autoinflammatory diseases has received extensive attention in recent years. Increasing evidence indicates that excess NETs exacerbate the inflammatory response in UC, disrupting the structure and function of the intestinal mucosal barrier and increasing the risk of thrombosis. Although NETs are usually assigned a deleterious role in promoting the pathological process of UC, they also appear to have a protective role in some models. Despite such progress, comprehensive reviews describing the therapeutic promise of NETs in UC remain limited. In this review, we discuss the latest evidence for the formation and degradation of NETs, focusing on their double-edged role in UC. Finally, the potential implications of NETs as therapeutic targets for UC will be discussed. This review aims to provide novel insights into the pathogenesis and therapeutic options for UC.

Bioinspired and bioderived nanomedicine for inflammatory bowel disease

Due to its chronic nature and complex pathophysiology, inflammatory bowel disease (IBD) poses significant challenges for treatment. The long-term therapies for patients, often diagnosed between the ages of 20 and 40, call for innovative strategies to target inflammation, minimize systemic drug exposure, and improve patients' therapeutic outcomes. Among the plethora of strategies currently pursued, bioinspired and bioderived nano-based formulations have garnered interest for their safety and versatility in the management of IBD. Bioinspired nanomedicine can host and deliver not only small drug molecules but also biotherapeutics, be made gastroresistant and mucoadhesive or mucopenetrating and, for these reasons, are largely investigated for oral administration, while surprisingly less for rectal delivery, recommended first-line treatment approach for several IBD patients. The use of bioderived nanocarriers, mostly extracellular vesicles (EVs), endowed with unique homing abilities, is still in its infancy with respect to the arsenal of nanomedicine under investigation for IBD treatment. An emerging source of EVs suited for oral administration is ingesta, that is, plants or milk, thanks to their remarkable ability to resist the harsh environment of the upper gastrointestinal tract. Inspired by the unparalleled properties of natural biomaterials, sophisticated avenues for enhancing therapeutic efficacy and advancing precision medicine approaches in IBD care are taking shape, although bottlenecks arising either from the complexity of the nanomedicine designed or from the lack of a clear regulatory pathway still hinder a smooth and efficient translation to the clinics. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Targeting programmed cell death in inflammatory bowel disease through natural products: New insights from molecular mechanisms to targeted therapies

Inflammatory bowel disease (IBD) is an autoimmune disorder primarily characterized by intestinal inflammation and recurrent ulceration, leading to a compromised intestinal barrier and inflammatory infiltration. This disorder's pathogenesis is mainly attributed to extensive damage or death of intestinal epithelial cells, along with abnormal activation or impaired death regulation of immune cells and the release of various inflammatory factors, which contribute to the inflammatory environment in the intestines. Thus, maintaining intestinal homeostasis hinges on balancing the survival and functionality of various cell types. Programmed cell death (PCD) pathways, including apoptosis, pyroptosis, autophagy, ferroptosis, necroptosis, and neutrophil extracellular traps, are integral in the pathogenesis of IBD by mediating the death of intestinal epithelial and immune cells. Natural products derived from plants, fruits, and vegetables have shown potential in regulating PCD, offering preventive and therapeutic avenues for IBD. This article reviews the role of natural products in IBD treatment by focusing on targeting PCD pathways, opening new avenues for clinical IBD management.

Neutrophil extracellular trap induction through peptidylarginine deiminase 4 activity is involved in 2,4,6-trinitrobenzenesulfonic acid-induced colitis

Neutrophil extracellular traps (NETs) are induced in the innate immune response against infectious agents and are also implicated in the pathogenesis of various cancers and autoimmune diseases. Peptidylarginine deiminase 4 (PAD4), an enzyme that converts arginine to citrulline, is also involved in NET formation. In this study, we investigated the pathogenic effect of PAD4 on NETs in inflammatory bowel disease using a trinitrobenzene sulfonic acid (TNBS)-induced murine colitis model. PAD4-deficient (PAD4KO) mice were generated by CRISPR-Cas9-mediated genomic editing. NETs were triggered in peritoneal neutrophils obtained from wild-type mice by A23187 (a calcium ionophore), but these responses were completely abolished in the PAD4KO mice. Experimental colitis was induced in wild-type and PAD4KO mice via an intrarectal injection of TNBS. TNBS injection resulted in body weight loss, extensive colonic erosion, and ulceration in wildtype mice. However, these responses were significantly attenuated following the administration of Cl-amidine (an inhibitor of pan-PADs) and DNase I (an inhibitor of NET formation), in combination with PAD4KO in mice. TNBS-induced increases in myeloperoxidase activity, inflammatory cytokine expression, and NET formation in the colon were significantly reduced following the administration of Cl-amidine, DNase I injection, and PAD4KO. These findings suggest that NET formation contributes to the pathogenesis of TNBS-induced colitis via PAD4. Thus, PAD4 is a promising target for the treatment of inflammatory bowel disease.

Extraction, purification, structural characterization and pharmacological activities of polysaccharides from sea buckthorn (Hippophae rhamnoides L.): A review

ETHNOPHARMACOLOGICAL RELEVANCE

Sea buckthorn (Hippophae rhamnoides L.) is an edible fruit with a long history in China as a medicinal plant. The fruits of H. rhamnoides are rich in a variety of nutrients and pharmacological active compounds. As one of the most important active ingredients in sea buckthorn, polysaccharides have attracted the attention of researchers due to their antioxidant, anti-fatigue, and liver protective qualities.

AIM OF THE REVIEW

This review summarizes recent studies on extraction, purification, structural characterization and pharmacological activities of polysaccharides from sea buckthorn. In addition, the relationship between the structure and the activities of sea buckthorn polysaccharides (SBPS) were discussed. This review would provide important research bases and up-to-date information for the future in-depth development and application of sea buckthorn polysaccharides in the field of pharmaceuticals and functional foods.

MATERIALS AND METHODS

By inputting the search term "Sea buckthorn polysaccharides", relevant research information was obtained from databases such as Web of Science, Google Scholar, PubMed, China Knowledge Network (CNKI), China Master Theses Full-text Database, and China Doctoral Dissertations Full-text Database.

RESULTS

The main extraction methods of SBPS include hot water extraction (HWE), ultrasonic assisted extraction (UAE), microwave-assisted extraction (MAE), flash extraction (FE), and ethanol extraction. More than 20 polysaccharides have been isolated from sea buckthorn fruits. The chemical structures of sea buckthorn polysaccharides obtained by different extraction, isolation, and purification methods are diverse. Polysaccharides from sea buckthorn display a variety of pharmacological properties, including antioxidant, anti-fatigue, liver protection, anti-obesity, regulation of intestinal flora, immunoregulation, anti-tumor, anti-inflammatory, and hypoglycemic activities.

CONCLUSIONS

Sea buckthorn has a long medicinal history and characteristics of an ethnic medicine and food. Polysaccharides are one of the main active components of sea buckthorn, and they have received increasing attention from researchers. Sea buckthorn polysaccharides have remarkable pharmacological activities, health benefits, and broad application prospects. In addition, further exploration of the chemical structure of SBPS, in-depth study of their pharmacological activities, identification of their material basis, characterization of disease resistance mechanisms, and potential health functions are still directions of future research. With the accumulation of research on the extraction and purification processes, chemical structure, pharmacological effects, molecular mechanisms, and structure-activity relationships, sea buckthorn polysaccharides derived from natural resources will ultimately make significant contributions to human health.

Neutrophil Extracellular Traps in Tumors and Potential Use of Traditional Herbal Medicine Formulations for Its Regulation

Neutrophil extracellular traps (NETs) are extracellular fibers composed of deoxyribonucleic acid (DNA) and decorated proteins produced by neutrophils. Recently, NETs have been associated with the development of many diseases, including tumors. Herein, we reviewed the correlation between NETs and tumors. In addition, we detailed active compounds from traditional herbal medicine formulations that inhibit NETs, related nanodrug delivery systems, and antibodies that serve as "guiding moieties" to ensure targeted delivery to NETs. Furthermore, we discussed the strategies used by pathogenic microorganisms to evade NETs.

Ca2+- and Zn2+-dependent nucleases co-participate in nuclear DNA degradation during programmed cell death in secretory cavity development in Citrus fruits

Calcium (Ca2+)- and zinc Zn2+-dependent nucleases play pivotal roles in plant nuclear DNA degradation in programmed cell death (PCD). However, the mechanisms by which these two nucleases co-participate in PCD-associated nuclear DNA degradation remain unclear. Here, the spatiotemporal expression patterns of two nucleases (CrCAN and CrENDO1) were analyzed qualitatively and quantitatively during PCD in secretory cavity formation in Citrus reticulata 'Chachi' fruits. Results show that the middle and late initial cell stages and lumen-forming stages are key stages for nuclear degradation during the secretory cavity development. CAN and ENDO1 exhibited potent in vitro DNA degradation activity at pH 8.0 and pH 5.5, respectively. Quantitative real-time reverse-transcription polymerase chain reaction, in situ hybridization assays, the subcellular localization of Ca2+ and Zn2+, and immunocytochemical localization showed that CrCAN was activated at the middle and late initial cell stages, while CrENDO1 was activated at the late initial cell and lumen-forming stages. Furthermore, we used immunocytochemical double-labelling to simultaneously locate CrCAN and CrENDO1. The DNA degradation activity of the two nucleases was verified by simulating the change of intracellular pH in vitro. Our results also showed that CrCAN and CrENDO1 worked respectively and co-participated in nuclear DNA degradation during PCD of secretory cavity cells. In conclusion, we propose the model for the synergistic effect of Ca2+- and Zn2+-dependent nucleases (CrCAN and CrENDO1) in co-participating in nuclear DNA degradation during secretory cavity cell PCD in Citrus fruits. Our findings provide direct experimental evidence for exploring different ion-dependent nucleases involved in nuclear degradation during plant PCD.

Recent advances on emerging nanomaterials for diagnosis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disorder that affects the entire gastrointestinal tract and is associated with an increased risk of colorectal cancer. Mainstream clinical testing methods are time-consuming, painful for patients, and insufficiently sensitive to detect early symptoms. Currently, there is no definitive cure for IBD, and frequent doses of medications with potentially severe side effects may affect patient response. In recent years, nanomaterials have demonstrated considerable potential for IBD management due to their diverse structures, composition, and physical and chemical properties. In this review, we provide an overview of the advances in nanomaterial-based diagnosis and treatment of IBD in recent five years. Multi-functional bio-nano platforms, including contrast agents, near-infrared (NIR) fluorescent probes, and bioactive substance detection agents have been developed for IBD diagnosis. Based on a series of pathogenic characteristics of IBD, the therapeutic strategies of antioxidant, anti-inflammatory, and intestinal microbiome regulation of IBD based on nanomaterials are systematically introduced. Finally, the future challenges and prospects in this field are presented to facilitate the development of diagnosis and treatment of IBD.

Role and Therapeutic Targeting Strategies of Neutrophil Extracellular Traps in Inflammation

Neutrophil extracellular traps (NETs) are large DNA reticular structures secreted by neutrophils and decorated with histones and antimicrobial proteins. As a key mechanism for neutrophils to resist microbial invasion, NETs play an important role in the killing of microorganisms (bacteria, fungi, and viruses). Although NETs are mostly known for mediating microbial killing, increasing evidence suggests that excessive NETs induced by stimulation of physical and chemical components, microorganisms, and pathological factors can exacerbate inflammation and organ damage. This review summarizes the induction and role of NETs in inflammation and focuses on the strategies of inhibiting NETosis and the mechanisms involved in pathogen evasion of NETs. Furthermore, herbal medicine inhibitors and nanodelivery strategies improve the efficiency of inhibition of excessive levels of NETs.

Alginate-based drug carrier systems to target inflammatory bowel disease: A review

Inflammatory bowel disease (IBD) is an inflammatory disorder that affects the gastrointestinal tract. IBD has become an increasingly common condition in both developed and developing nations over the last few decades, owing to a variety of factors like a rising population and diets packed with processed and junk foods. While the root pathophysiology of IBD is unknown, treatments are focused on medications aimed to mitigate symptoms. Alginate (AG), a marine-derived polysaccharide, is extensively studied for its biocompatibility, pH sensitivity, and crosslinking nature. This polymer is thoroughly researched in drug delivery systems for IBD treatment, as it is naturally available, non-toxic, cost effective, and can be easily and safely cross-linked with other polymers to form an interconnected network, which helps in controlling the release of drugs over an extended period. There are various types of drug delivery systems developed from AG to deliver therapeutic agents; among them, nanotechnology-based systems and hydrogels are popular due to their ability to facilitate targeted drug delivery, reduce dosage, and increase the therapeutic efficiency. AG-based carrier systems are not only used for the sustained release of drug, but also used in the delivery of siRNA, interleukins, and stem cells for site directed drug delivery and tissue regenerating ability respectively. This review is focussed on pathogenesis and currently studied medications for IBD, AG-based drug delivery systems and their properties for the alleviation of IBD. Moreover, future challenges are also be discoursed to improve the research of AG in the field of biopharmaceuticals and drug delivery.

Socs3 expression in myeloid cells modulates the pathogenesis of dextran sulfate sodium (DSS)-induced colitis

Introduction

Myeloid cells play a critical role in the pathogenesis of Inflammatory Bowel Diseases (IBDs), including Ulcerative Colitis (UC) and Crohn's Disease (CD). Dysregulation of the JAK/STAT pathway is associated with many pathological conditions, including IBD. Suppressors Of Cytokine Signaling (SOCS) are a family of proteins that negatively regulate the JAK/STAT pathway. Our previous studies identified that mice lacking Socs3 in myeloid cells developed a hyper-activated phenotype of macrophages and neutrophils in a pre-clinical model of Multiple Sclerosis.

Methods

To better understand the function of myeloid cell Socs3 in the pathogenesis of colitis, mice with Socs3 deletion in myeloid cells (Socs3 ^ΔLysM) were utilized in a DSS-induced colitis model.

Results

Our results indicate that Socs3 deficiency in myeloid cells leads to more severe colitis induced by DSS, which correlates with increased infiltration of monocytes and neutrophils in the colon and increased numbers of monocytes and neutrophils in the spleen. Furthermore, our results demonstrate that the expression of genes related to the pathogenesis and diagnosis of colitis such as Il1β, Lcn2, S100a8 and S100a9 were specifically enhanced in Socs3-deficient neutrophils localized to the colon and spleen. Conversely, there were no observable differences in gene expression in Ly6C⁺ monocytes. Depletion of neutrophils using a neutralizing antibody to Ly6G significantly improved the disease severity of DSS-induced colitis in Socs3-deficient mice.

Discussion

Thus, our results suggest that deficiency of Socs3 in myeloid cells exacerbates DSS-induced colitis and that Socs3 prevents overt activation of the immune system in IBD. This study may provide novel therapeutic strategies to IBD patients with hyperactivated neutrophils.

Mucoadhesive Nanoparticles Enhance the Therapeutic Effect of Dexamethasone on Experimental Ulcerative Colitis by the Local Administration as an Enema

Background

As the first-line drug to treat ulcerative colitis (UC), long-term use of glucocorticoids (GCs) produces severe toxic and side effects. Local administration as enema can increase the local GCs concentrations and reduce systemic exposure to high oral doses by directly delivering GCs to the inflammation site in the distal colorectum. However, UC patients are often accompanied by diarrhea, leading to the short colonic residence time of GCs and failure to exert their function fully.

Purpose

A kind of mucoadhesive nanoparticles (NPs) loading different dexamethasone derivatives (DDs) were developed, which could attach to the positively charged inflammatory colonic mucosa through electrostatic adsorption after administered by enema, thereby improving the local concentration and achieving effective targeted therapy for UC.

Methods

Two DDs, dexamethasone hemisuccinate and dexamethasone phosphate, were synthesized. In NPs preparation, The core PEI-DDs NPs were built by the electrostatic adsorption of DDs and the cationic polymer polyethyleneimine (PEI). Then, the natural polyanionic polysaccharide sodium alginate (SA) was electronically coated around NPs to construct the final SA-PEI-DDs NPs, followed by the in vitro stability and release tests, in vitro and in vivo colonic mucosal adhesion tests. In the in vivo anti-UC test, the experimental colitis mice were induced by 2,4,6-trinitrobenzenesulfonic acid. The body weight and disease activity index changes were measured, and the myeloperoxidase activity, pro-inflammatory cytokines concentration, and hematoxylin and eosin staining were also investigated to evaluate the therapeutic effect of NPs.

Results

The structures of two DDs were demonstrated by ¹H-NMR and MS. Both NPs were negatively charged and achieved high loading efficiency of DDs, while their particle sizes were significantly different. NPs showed good stability and sustained release properties in the simulated colonic environment. Moreover, the negative charge on the of NPs surface made them easier to adhere to the positively charged inflammatory colonic mucosa, thereby enhancing the enrichment and retention of DDS in the colitis site. Furthermore, the NPs exhibited better therapeutic effects than free Dex on the experimental colitis mice induced by TNBS through the enema rectal.

Conclusion

These results indicated the mucoadhesive NPs as a kind of novel nano-enema showed great potential to achieve efficient treatment on UC.

Pathophysiology of Inflammatory Bowel Disease: Innate Immune System

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation with no exact known cause. Intestinal innate immunity is enacted by neutrophils, monocytes, macrophages, and dendritic cells (DCs), and innate lymphoid cells and NK cells, characterized by their capacity to produce a rapid and nonspecific reaction as a first-line response. Innate immune cells (IIC) defend against pathogens and excessive entry of intestinal microorganisms, while preserving immune tolerance to resident intestinal microbiota. Changes to this equilibrium are linked to intestinal inflammation in the gut and IBD. IICs mediate host defense responses, inflammation, and tissue healing by producing cytokines and chemokines, activating the complement cascade and phagocytosis, or presenting antigens to activate the adaptive immune response. IICs exert important functions that promote or ameliorate the cellular and molecular mechanisms that underlie and sustain IBD. A comprehensive understanding of the mechanisms underlying these clinical manifestations will be important for developing therapies targeting the innate immune system in IBD patients. This review examines the complex roles of and interactions among IICs, and their interactions with other immune and non-immune cells in homeostasis and pathological conditions.

The role of protein arginine deiminase 4-dependent neutrophil extracellular traps formation in ulcerative colitis

Background

Neutrophil extracellular traps (NETs) play an important role in the development and progression of ulcerative colitis (UC). Peptidyl arginine deiminase 4 (PAD4) is essential for the formation of NETs via catalyzing histone citrullination. This study mainly to explore the role of PAD4-mediated NETs in intestinal inflammation of dextran sulfate sodium (DSS)-induced UC.

Methods

Acute and chronic colitis mouse models were established by supplementing DSS in drinking water. Colon tissues from colitis mice were analyzed for the level of PAD4 expression, citrullinated histone H3(Cit-H3), intestinal histopathology, and inflammatory cytokines secretion. Serum samples were tested for systemic neutrophil activation biomarkers. Colitis mice administered with Cl-amidine, a PAD4 inhibitor, and PAD4 knockout mice were investigated to detect NETs formation, intestinal inflammation, and barrier function.

Result

We found the formation of NETs significantly increased in DSS-induced colitis mice and was correlated with disease markers. Blocking NETs formation by Cl-amidine or PAD4 genetic knockout could alleviate clinical colitis index, intestinal inflammation, and barrier dysfunction.

Conclusion

This study provided a research basis for the role of PAD4-mediated NETs formation in the pathogenesis of UC and suggested that inhibition of PAD4 activity and the formation of NETs may be helpful for the prevention and treatment of UC.

Triclocarban evoked neutrophil extracellular trap formation in common carp (Cyprinus carpio L.) by modulating SIRT3-mediated ROS crosstalk with ERK1/2/p38 signaling

Triclocarban (TCC), an antimicrobial ingredient in personal care products, is associated with immunosuppression and physiological dysfunctions of aquatic organisms. The aim of this study was to investigate whether TCC can induce common carp NETosis (neutrophil death by neutrophil extracellular trap (NET) release) and then to attempt to identify the potential molecular mechanisms. Herein, scanning electron microscopy and flow cytometric assays showed that revealed that TCC triggers DNA-containing web-like structures and increases extracellular DNA content. In the proteomic analysis, we observed that NET-related proteins, extracellular regulated protein kinase (Mapk1, Mapk14, Jak2) and apoptotic protein (caspase3) were significantly increased, and defender against cell death 1 (Dad1) was significantly decreased after TCC treatments. Meanwhile, we confirmed that TCC stress can trigger NETosis in common carp by activating the reactive oxygen species (ROS)/ERK1/2/p38 signaling. We think that the upregulated NDUFS1 expression is closely related to oxidative stress induced by TCC. Importantly, we discovered that SIRT3 expression was significantly decreased in the process of TCC-induced NETs. Importantly, pretreatment with the SIRT3 agonist honokiol (HKL) effectively suppressed TCC-induced NET release. In contrast, the SIRT3 antagonist 3-TYP escalated TCC-induced NET formation. Mechanistically, SIRT3 degradation serves as a potential mediator for regulating oxidative stress crosstalk between ERK1/2/p38 signals in the process of TCC-induced NET formation. These findings unveil new insights into the TCC-evoked health risk of fish and other aquatic organisms and suggest that SIRT3 is a potential pharmacological intervention target to alleviate TCC-induced common carp NETosis.

The emerging role of neutrophilic extracellular traps in intestinal disease

Neutrophil extracellular traps (NETs) are extracellular reticular fibrillar structures composed of DNA, histones, granulins and cytoplasmic proteins that are delivered externally by neutrophils in response to stimulation with various types of microorganisms, cytokines and host molecules, etc. NET formation has been extensively demonstrated to trap, immobilize, inactivate and kill invading microorganisms and acts as a form of innate response against pathogenic invasion. However, NETs are a double-edged sword. In the event of imbalance between NET formation and clearance, excessive NETs not only directly inflict tissue lesions, but also recruit pro-inflammatory cells or proteins that promote the release of inflammatory factors and magnify the inflammatory response further, driving the progression of many human diseases. The deleterious effects of excessive release of NETs on gut diseases are particularly crucial as NETs are more likely to be disrupted by neutrophils infiltrating the intestinal epithelium during intestinal disorders, leading to intestinal injury, and in addition, NETs and their relevant molecules are capable of directly triggering the death of intestinal epithelial cells. Within this context, a large number of NETs have been reported in several intestinal diseases, including intestinal infections, inflammatory bowel disease, intestinal ischemia–reperfusion injury, sepsis, necrotizing enterocolitis, and colorectal cancer. Therefore, the formation of NET would have to be strictly monitored to prevent their mediated tissue damage. In this review, we summarize the latest knowledge on the formation mechanisms of NETs and their pathophysiological roles in a variety of intestinal diseases, with the aim of providing an essential directional guidance and theoretical basis for clinical interventions in the exploration of mechanisms underlying NETs and targeted therapies.

Interactions between Nanoparticles and Intestine

The use of nanoparticles (NPs) has surely grown in recent years due to their versatility, with a spectrum of applications that range from nanomedicine to the food industry. Recent research focuses on the development of NPs for the oral administration route rather than the intravenous one, placing the interactions between NPs and the intestine at the centre of the attention. This allows the NPs functionalization to exploit the different characteristics of the digestive tract, such as the different pH, the intestinal mucus layer, or the intestinal absorption capacity. On the other hand, these same characteristics can represent a problem for their complexity, also considering the potential interactions with the food matrix or the microbiota. This review intends to give a comprehensive look into three main branches of NPs delivery through the oral route: the functionalization of NPs drug carriers for systemic targets, with the case of insulin carriers as an example; NPs for the delivery of drugs locally active in the intestine, for the treatment of inflammatory bowel diseases and colon cancer; finally, the potential concerns and side effects of the accidental and uncontrolled exposure to NPs employed as food additives, with focus on E171 (titanium dioxide) and E174 (silver NPs).

Inhibition of PAD4-mediated NET formation by cl-amidine prevents diabetes development in nonobese diabetic mice

Many evidences indicated that neutrophil extracellular traps (NETs) play pathogenic roles in type 1 diabetes (T1D). Peptidylarginine deiminases 4 (PAD4) has been proved to be indispensable for generation of NETs. In the current study, we investigated whether oral administration of cl-amidine, an effective inhibitor of PAD4, protects non-obese diabetic (NOD) mice from T1D development. Female NOD mice were orally administrated with cl-amidine (5 μg/g body weight) from the age of 8 weeks up to 16 weeks. It showed that cl-amidine inhibit NET formation in vitro and in vivo. The onset of T1D was delayed nearly 8 weeks and the incidence of disease was significantly decreased in cl-amidine treated mice compared with the control group. Moreover, cl-amidine decreased the serum levels of anti-citrullinated peptide antibody (ACPA) and anti-neutrophil cytoplasmic antibodies (ANCA) in NOD mice. Also, it decreased generation of T1D autoantibodies such as glutamic acid decarboxylase antibody (GADA), tyrosine phosphatase-related islet antigen-2 antibody (IA2A) and zinc transporter 8 antibody (ZnT8A), which were strongly correlated with the reduced serum PAD4 and MPO-DNA levels. Furthermore, cl-amidine administration inhibited pancreatic inflammation and increased frequency of regulatory T cells in pancreatic lymph nodes (PLNs). In addition, cl-amidine improved gut barrier dysfunction and decreased the serum level of lipopolysaccharide (LPS), which was positively correlated with the NETs markers (PAD4 and MPO-DNA) and T1D autoantibody IA2A. In conclusion, our data showed that orally delivery of cl-amidine effectively prevent T1D development and suggested inhibition of PAD4-dependent NET formation as a potential way of clinical treatment in T1D.

Neutrophils in chronic inflammatory diseases

Chronic inflammation is a component of many disease conditions that affect a large group of individuals worldwide. Chronic inflammation is characterized by persistent, low-grade inflammation and is increased in the aging population. Neutrophils are normally the first responders to acute inflammation and contribute to the resolution of inflammation. However, in chronic inflammation, the role of neutrophils is less well understood and has been described as either beneficial or detrimental, causing tissue damage and enhancing the immune response. Emerging evidence suggests that neutrophils are important players in several chronic diseases, such as atherosclerosis, diabetes mellitus, nonalcoholic fatty liver disease and autoimmune disorders. This review will highlight the interaction of neutrophils with other cells in the context of chronic inflammation, the contribution of neutrophils to selected chronic inflammatory diseases, and possible future therapeutic strategies.