Overt Increase of Oxidative Stress and DNA Damage in Murine and Human Colitis and Colitis-Associated Neoplasia

Pollutants, microbiota and immune system: frenemies within the gut

Pollution is a critical concern of modern society for its heterogeneous effects on human health, despite a widespread lack of awareness. Environmental pollutants promote several pathologies through different molecular mechanisms. Pollutants can affect the immune system and related pathways, perturbing its regulation and triggering pro-inflammatory responses. The exposure to several pollutants also leads to alterations in gut microbiota with a decreasing abundance of beneficial microbes, such as short-chain fatty acid-producing bacteria, and an overgrowth of pro-inflammatory species. The subsequent intestinal barrier dysfunction, together with oxidative stress and increased inflammatory responses, plays a role in the pathogenesis of gastrointestinal inflammatory diseases. Moreover, pollutants encourage the inflammation-dysplasia-carcinoma sequence through various mechanisms, such as oxidative stress, dysregulation of cellular signalling pathways, cell cycle impairment and genomic instability. In this narrative review, we will describe the interplay between pollutants, gut microbiota, and the immune system, focusing on their relationship with inflammatory bowel diseases and colorectal cancer. Understanding the biological mechanisms underlying the health-to-disease transition may allow the design of public health policies aimed at reducing the burden of disease related to pollutants.

The Role of Wheatgrass in Colorectal Cancer: A Review of the Current Evidence

The etiology of colon cancer is either genetic in nature or results from inflammatory bowel diseases such as ulcerative colitis and Crohn's disease; nevertheless, dietary habits play a crucial role in the disease. Wheatgrass is a dietary supplement that is rich in vitamins, minerals, and antioxidants which contribute to health promotion in cardiovascular diseases, liver disease, blood diseases, diabetes, and inflammatory bowel diseases, as well as in several types of cancers, such as oral squamous cell cancer, cervical cancer, and breast cancer. In colorectal cancer (CRC), the prospect that wheatgrass possesses anti-inflammatory, antioxidant, and anticancer properties, and its use as an adjunctive therapy, have been minimally investigated and evidence is still limited. In this review, we compiled the available evidence pertaining to wheatgrass and its likely impact on CRC, described the pathways of inflammation in which wheatgrass could possibly play a role, and identified future research needs on the subject.

Red/NIR-I-Fluorescence Carbon Dots Based on Rhein with Active Oxygen Scavenging and Colitis Targeting for UC Therapeutics

Ulcerative colitis (UC) is a chronic inflammatory disease with uncontrolled inflammation and demage to the intestinal barrier. Rhein, a bioactive compound in traditional Chinese medicine, has anti-inflammatory and intestinal repair effect. However, their clinical application is limited by their hydrophobicity and poor bioavailability. L-arginine, as a complement to NO, has synergistic and attenuating effects. In this paper, red/NIR-I fluorescent carbon dots based on rhein and doped with L-arginine (RA-CDs), which are synthesized by a hydrothermal process without any organic solvents, are reported. RA-CDs preserve a portion of the functional group of the active precursor, increase rhein solubility, and emit red/NIR-I light for biological imaging. In vitro experiments show that RA-CDs scavenge excessive reactive oxygen species (ROS), protect cells from oxidative stress, and enable the fluorescence imaging of inflamed colons. In a DSS-induced UC mouse model, both delayed and prophylactic treatment with RA-CDs via intraperitoneal and tail vein injections alleviate UC severity by reducing intestinal inflammation and restoring the intestinal barrier. This study highlights a novel strategy for treating and imaging UC with poorly soluble small-molecule drugs.

Inflammatory microenvironment in gastric premalignant lesions: implication and application

Gastric precancerous lesions (GPL) are a major health concern worldwide due to their potential to progress to gastric cancer (GC). Understanding the mechanism underlying the transformation from GPL to GC can provide a fresh insight for the early detection of GC. Although chronic inflammation is prevalent in the GPL, how the inflammatory microenvironment monitored the progression of GPL-to-GC are still elusive. Inflammation has been recognized as a key player in the progression of GPL. This review aims to provide an overview of the inflammatory microenvironment in GPL and its implications for disease progression and potential therapeutic applications. We discuss the involvement of inflammation in the progression of GPL, highlighting Helicobacter pylori (H. pylori) as a mediator for inflammatory microenvironment and a key driver to GC progression. We explore the role of immune cells in mediating the progression of GPL, and focus on the regulation of inflammatory molecules in this disease. Furthermore, we discuss the potential of targeting inflammatory pathways for GPL. There are currently no specific drugs for GPL treatment, but traditional Chinese Medicine (TCM) and natural antioxidants, known as antioxidant and anti-inflammatory properties, exhibit promising effects in suppressing or reversing the progression of GPL. Finally, the challenges and future perspectives in the field are proposed. Overall, this review highlights the central role of the inflammatory microenvironment in the progression of GPL, paving the way for innovative therapeutic approaches in the future.

Carcinogenic risk in the biliary epithelium of children with congenital biliary dilatation via the DNA damage repair pathway

PURPOSES

Congenital biliary dilatation (CBD) is a high-risk factor for biliary tract cancer (BTC). We previously reported the potential for carcinogenesis in the biliary epithelium of patients with CBD. In this study, we investigated potential carcinogenetic pathways, focusing on the DNA damage repair response, in children with CBD and compared the findings with those in adults.

METHODS

We enrolled 6 children with CBD and 10 adults with CBD without BTC who underwent extrahepatic bile duct resections, plus 4 control patients who underwent pancreaticoduodenectomy for non-biliary cancer. Levels of phosphorylated histone H2AX (γH2AX), MRE11, and Ku-70 in the biliary tract epithelium were evaluated by immunohistochemistry.

RESULTS

The levels of γH2AX, MRE11, and Ku-70 were significantly higher in the gallbladder epithelium and bile duct epithelium of both children and adults than in controls.

CONCLUSIONS

Children and adults with CBD might develop BTC via the DNA damage repair pathway, as evidenced by increased γH2AX, MRE11, and Ku-70 expression.

Colonic expression of glutathione S-transferase alpha 4 and 4-hydroxynonenal adducts is correlated with the pathology of murine colitis-associated cancer

Chronic inflammation-induced oxidative stress is an important driving force for developing colitis-associated cancer (CAC). 4-hydroxynonenal (4-HNE) is a highly reactive aldehyde derived from lipid peroxidation of ω-6 polyunsaturated fatty acids that contributes to colorectal carcinogenesis. Glutathione S-transferase alpha 4 (Gsta4) specifically conjugates glutathione to 4-HNE and thereby detoxifies 4-HNE. The correlation of these oxidative biomarkers with the pathological changes in CAC is, however, unclear. In this study, we investigated the expression of Gsta4 and 4-HNE adducts in azoxymethane/dextran sulfate sodium (AOM/DSS)-induced murine CAC, and analyzed the correlations of 4-HNE and Gsta4 with inflammatory cytokines and the pathological scores in the colon biopsies. Real-time quantitative PCR showed that expression of IL6, TNFα, and Gsta4 sequentially increased in colon tissues for mice treated with DSS for 1, 2, and 3 cycles, respectively. Moreover, immunohistochemical staining showed remarkably increased expression of 4-HNE adducts, Gsta4, TNFα, and IL6 in the colon biopsies after 3 cycles of DSS treatment. Correlation analysis demonstrated that 4-HNE adducts in the colon biopsies were positively correlated with Gsta4 expression. Additionally, the expression of Gsta4 and 4-HNE adducts were strongly correlated with the pathological changes of colon, as well as the expression of TNFα and IL6 in colon tissues. These results provide evidence for the association of oxidative biomarkers Gsta4 and 4-HNE with the pathological changes of CAC and may help developing novel histopathological biomarkers and prevention targets for CAC.

Inflammatory Bowel Disease and Colorectal Cancer: Epidemiology, Etiology, Surveillance, and Management

Patients with inflammatory bowel diseases (IBDs), such as ulcerative colitis and Crohn's disease, have an increased risk of developing colorectal cancer (CRC). Although advancements in endoscopic imaging techniques, integrated surveillance programs, and improved medical therapies have contributed to a decreased incidence of CRC in patients with IBD, the rate of CRC remains higher in patients with IBD than in individuals without chronic colitis. Patients with IBD-related CRCs exhibit a poorer prognosis than those with sporadic CRCs, owing to their aggressive histological characteristics and lower curative resection rate. In this review, we present an updated overview of the epidemiology, etiology, risk factors, surveillance strategies, treatment recommendations, and prognosis of IBD-related CRCs.

Update and latest advances in mechanisms and management of colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CAC) is defined as a specific cluster of colorectal cancers that develop as a result of prolonged colitis in patients with inflammatory bowel disease (IBD). Patients with IBD, including ulcerative colitis and Crohn's disease, are known to have an increased risk of developing CAC. Although the incidence of CAC has significantly decreased over the past few decades, individuals with CAC have increased mortality compared to individuals with sporadic colorectal cancer, and the incidence of CAC increases with duration. Chronic inflammation is generally recognized as a major contributor to the pathogenesis of CAC. CAC has been shown to progress from colitis to dysplasia and finally to carcinoma. Accumulating evidence suggests that multiple immune-mediated pathways, DNA damage pathways, and pathogens are involved in the pathogenesis of CAC. Over the past decade, there has been an increasing effort to develop clinical approaches that could help improve outcomes for CAC patients. Colonoscopic surveillance plays an important role in reducing the risk of advanced and interval cancers. It is generally recommended that CAC patients undergo endoscopic removal or colectomy. This review summarizes the current understanding of CAC, particularly its epidemiology, mechanisms, and management. It focuses on the mechanisms that contribute to the development of CAC, covering advances in genomics, immunology, and the microbiome; presents evidence for management strategies, including endoscopy and colectomy; and discusses new strategies to interfere with the process and development of CAC. These scientific findings will pave the way for the management of CAC in the near future.

Surgical Treatment in Ulcerative Colitis, Still Topical: A Narrative Review

In this paper, different studies were integrated to conclude the impact of ulcerative colitis (UC) on the patient's vital prognosis, specifically highlighting the association with colorectal cancer (CRC). These severe complications have led us to consider studying the role of preventive surgery in managing UC. This study reviewed total preventive colectomy in UC patients for preventing the onset of CRC, the role of surgery in UC management, and its potential as a definitive treatment for the condition. The study also emphasized the effectiveness of annual colonoscopic monitoring and preventive colectomy in reducing the incidence of colorectal cancer (CRC). It discussed the role of laparoscopic surgery in minimizing postoperative complications and highlighted that partial surgical resection of the colon can be a viable option, offering improved bowel function without increasing the risk of CRC-related mortality. Elective surgery has an important place in UC management by preventing the development of forms requiring emergency surgery. Although surgery can cure UC, it can lead to significant postoperative complications and adverse effects.

Inflammation-Driven Colorectal Cancer Associated with Colitis: From Pathogenesis to Changing Therapy

Patients affected by inflammatory bowel disease (IBD) have a two-fold higher risk of developing colorectal cancer (CRC) than the general population. IBD-related CRC follows a different genetic and molecular pathogenic pathway than sporadic CRC and can be considered a complication of chronic intestinal inflammation. Since inflammation is recognised as an independent risk factor for neoplastic progression, clinicians strive to modulate and control disease, often using potent therapy agents to achieve mucosal healing and decrease the risk of colorectal cancer in IBD patients. Improved therapeutic control of inflammation, combined with endoscopic advances and early detection of pre-cancerous lesions through surveillance programs, explains the lower incidence rate of IBD-related CRC. In addition, current research is increasingly focused on translating emerging and advanced knowledge in microbiome and metagenomics into personalised, early, and non-invasive CRC screening tools that guide organ-sparing therapy in IBD patients. This review aims to summarise the existing literature on IBD-associated CRC, focusing on new insights into the alteration of the intestinal barrier and the interactions with the gut microbiome as the initial promoter. In addition, the role of OMIC techniques for precision medicine and the impact of the available IBD therapeutic armamentarium on the evolution to CRC will be discussed.

Promoting Effect of L-Fucose on the Regeneration of Intestinal Stem Cells through AHR/IL-22 Pathway of Intestinal Lamina Propria Monocytes

The recovery of the intestinal epithelial barrier is the goal for curing various intestinal injurious diseases, especially IBD. However, there are limited therapeutics for restoring intestinal epithelial barrier function in IBD. The stemness of intestinal stem cells (ISCs) can differentiate into various mature intestinal epithelial cells, thus playing a key role in the rapid regeneration of the intestinal epithelium. IL-22 secreted by CD4⁺ T cells and ILC3 cells was reported to maintain the stemness of ISCs. Our previous study found that L-fucose significantly ameliorated DSS-induced colonic inflammation and intestinal epithelial injury. In this study, we discovered enhanced ISC regeneration and increased intestinal IL-22 secretion and its related transcription factor AHR in colitis mice after L-fucose treatment. Further studies showed that L-fucose promoted IL-22 release from CD4⁺ T cells and intestinal lamina propria monocytes (LPMCs) via activation of nuclear AHR. The coculture system of LPMCs and intestinal organoids demonstrated that L-fucose stimulated the proliferation of ISCs through an indirect manner of IL-22 from LPMCs via the IL-22R-p-STAT3 pathway, and restored TNF-α-induced organoid damage via IL-22-IL-22R signaling. These results revealed that L-fucose helped to heal the epithelial barrier by accelerating ISC proliferation, probably through the AHR/IL-22 pathway of LPMCs, which provides a novel therapy for IBD in the clinic.

Role of the E3 ubiquitin-ligase Hakai in intestinal inflammation and cancer bowel disease

The E3 ubiquitin-ligases are important for cellular protein homeostasis and their deregulation is implicated in cancer. The E3 ubiquitin-ligase Hakai is involved in tumour progression and metastasis, through the regulation of the tumour suppressor E-cadherin. Hakai is overexpressed in colon cancer, however, the implication in colitis-associated cancer is unknown. Here, we investigated the potential role of Hakai in intestinal inflammation and cancer bowel disease. Several mouse models of colitis and associated cancer were used to analyse Hakai expression by immunohistochemistry. We also analysed Hakai expression in patients with inflamed colon biopsies from ulcerative colitis and Crohn's disease. By Hakai interactome analysis, it was identified Fatty Acid Synthase (FASN) as a novel Hakai-interacting protein. Moreover, we show that Hakai induces FASN ubiquitination and degradation via lysosome, thus regulating FASN-mediated lipid accumulation. An inverse expression of FASN and Hakai was detected in inflammatory AOM/DSS mouse model. In conclusion, Hakai regulates FASN ubiquitination and degradation, resulting in the regulation of FASN-mediated lipid accumulation, which is associated to the development of inflammatory bowel disease. The interaction between Hakai and FASN may be an important mechanism for the homeostasis of intestinal barrier function and in the pathogenesis of this disease.

Ultrathin Hafnium Disulfide Atomic Crystals with ROS-Scavenging and Colon-Targeting Capabilities for Inflammatory Bowel Disease Treatment

The exciting success of NBTXR3 in the clinic has triggered a tumult of activities in the design and development of hafnium-based nanoparticles. However, due to the concerns of nondegradation and limited functions, the biomedical applications of Hf-based nanoparticles mainly focus on tumors. Herein, tannic acid capped hafnium disulfide (HfS₂@TA) nanosheets, a 2D atomic crystal of hafnium-based materials prepared by liquid-phase exfoliation, were explored as high-performance anti-inflammatory nanoagents for the targeted therapy of inflammatory bowel disease (IBD). Benefiting from the transformation of the S^2-/S⁶⁺ valence state and huge specific surface area, the obtained HfS₂@TA nanosheets were not only capable of effectively eliminating reactive oxygen species/reactive nitrogen species and downregulating pro-inflammatory factors but also could be excreted via kidney and hepatointestinal systems. Unexpectedly, HfS₂@TA maintained excellent targeting capability to an inflamed colon even in the harsh digestive tract environment, mainly attributed to the electrostatic interactions between negatively charged tannic acid and positively charged inflamed epithelium. Encouragingly, upon oral or intravenous administration, HfS₂@TA quickly inhibited inflammation and repaired the intestinal mucosa barrier in both dextran sodium sulfate and 2,4,6-trinitrobenzenesulfonic acid induced IBD models. This work demonstrated that ultrathin HfS₂@TA atomic crystals with enhanced colon accumulation were promising for the targeted therapy of IBD.

Inflammatory bowel disease induces inflammatory and pre-neoplastic changes in the prostate

BACKGROUND

Inflammatory bowel disease (IBD) has been implicated as a risk factor for prostate cancer, however, the mechanism of how IBD leads to prostate tumorigenesis is not known. Here, we investigated whether chronic intestinal inflammation leads to pro-inflammatory changes associated with tumorigenesis in the prostate.

METHODS

Using clinical samples of men with IBD who underwent prostatectomy, we analyzed whether prostate tumors had differences in lymphocyte infiltrate compared to non-IBD controls. In a mouse model of chemically-induced intestinal inflammation, we investigated whether chronic intestinal inflammation could be transferred to the wild-type mouse prostate. In addition, mouse prostates were evaluated for activation of pro-oncogenic signaling and genomic instability.

RESULTS

A higher proportion of men with IBD had T and B lymphocyte infiltration within prostate tumors. Mice with chronic colitis showed significant increases in prostatic CD45 + leukocyte infiltration and elevation of three pro-inflammatory cytokines-TIMP-1, CCL5, and CXCL1 and activation of AKT and NF-kB signaling pathways. Lastly, mice with chronic colitis had greater prostatic oxidative stress/DNA damage, and prostate epithelial cells had undergone cell cycle arrest.

CONCLUSIONS

These data suggest chronic intestinal inflammation is associated with an inflammatory-rich, pro-tumorigenic prostatic phenotype which may explain how gut inflammation fosters prostate cancer development in men with IBD.

Polysaccharides from Garlic Protect against Liver Injury in DSS-Induced Inflammatory Bowel Disease of Mice via Suppressing Pyroptosis and Oxidative Damage

Inflammatory bowel disease (IBD), a widespread intestinal disease threatening human health, is commonly accompanied by secondary liver injury (SLI). Pyroptosis and oxidative stress act as an important role underlying the pathophysiology of SLI, during which a large number of proinflammatory cytokines and oxidative intermediates can be produced, thereby causing the liver severely damaged. Suppression of pyroptosis and oxidative damage can be considered one of the critical strategies for SLI therapy. Garlic, a natural food with eatable and medicinal functions, is widely used in people's daily life. There is no study about the alleviation of garlic against IBD accompanied with SLI. This study is aimed at investigating the efficacy of the polysaccharides from garlic (PSG) in treating IBD and SLI, as well as its pharmacological mechanism. The results showed that PSG significantly alleviated dextran sulfate sodium-induced IBD determined by evaluating the bodyweight loss, disease activity index, colon length, and colonic pathological examination of mice. PSG significantly reduced the colonic inflammation by reversing the levels of myeloperoxidase, diamine oxidase activity, iNOS, and COX2 and strengthened the intestinal barrier by increasing the expressions of ZO1, occludin, and MUC2 of IBD mice. Furthermore, PSG strongly alleviated SLI determined by assessing the liver morphological change, liver index, levels of ALT and AST, and liver pathological change of mice. Mechanically, PSG reduced the high levels of LPS, IL-1β, IL18, NLRP3, gasdermin D, caspase 1, ASC, TLR4, MyD88, NF-κB, phospho-NF-κB, while it increased IL-10 in the livers of mice, indicating that PSG alleviated SLI by suppressing inflammation and pyroptosis. Additionally, PSG significantly inhibited the oxidative damage in the liver tissues of SLI mice by reducing the levels of ROS, MDA, Keap-1, 8-OHDG, and phospho-H2AX and increasing the levels of GPX4, SOD2, HO1, NQO1, and Nrf2. These findings suggested that the garlic polysaccharides could be used to treat IBD accompanied with SLI in humans.

Mechanism of Fructus Mume Pills Underlying Their Protective Effects in Rats with Acetic Acid-Inducedulcerative Colitis via the Regulation of Inflammatory Cytokines and the VEGF-PI3K/Akt-eNOS Signaling Pathway

Background

Fructus mume pills (FMPs) have been clinically proven to be effective for treating ulcerative colitis (UC). However, the therapeutic and protective mechanisms have not been fully studied.

Aim

We aimed to explore the mechanism of FMPs in an acetic acid (AA)-induced ulcerative colitis rat model.

Methods

The targets, GO terms, and KEGG pathways for the FMPs and UC were screened and constructed using network pharmacology. A possible mechanism was verified in a 4% AA-induced colitis rat model. Colitis activity and state were evaluated using the disease activity index, and colon ulceration and intestinal mucosal damage were determined by histopathological observation through HE, AB-PAS, and Masson pathological staining. The concentrations of TNF-α, IL-6, IL-8, IL-10, MPO, MMP9, CXCR1, eNOS, and VEGF were measured to evaluate vascular permeability effects.

Results

The network pharmacology results showed 108 active compounds, and 139 FMP-related targets were identified. Twenty-nine targets were identified for FMPs against UC, which included MMP9, MMP3, ESR1, PTGS1, PPARA, MPO, and NOS2. A total of 1,536 GO terms and 41 pathways were associated with FMP treatment of UC. The pharmacological evaluation showed that FMPs attenuated inflammation in AA-induced colitis by reducing the serum concentrations of TNF-α, IL-6, IL-8, and IL-10 and the colonic concentrations of MPO, MMP9, and CXCR1. FMPs ameliorated hyperpermeability by reducing the colonic VEGF and eNOS concentrations. FMPs also significantly decreased the VEGFA, VEGFR2, Src, and eNOS protein expressions in colon tissue through the VEGF-PI3K/Akt-eNOS signaling pathway.

Conclusion

These results suggest that FMPs control UC inflammation by regulating inflammatory cytokine concentrations. FMPs alleviate AA-induced UC by regulating microvascular permeability through the VEGF-PI3K/Akt-eNOS signaling pathway.

Colorectal Cancer in Inflammatory Bowel Disease: Mechanisms and Management

Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer (CRC), despite decreases in CRC incidence in recent years. Chronic inflammation is the driver of neoplastic progression, resulting in dysplastic precursor lesions that may arise in multiple areas of the colon through a process of field cancerization. Colitis-associated CRC shares many molecular similarities with sporadic CRC, and preclinical investigations have demonstrated a potential role for the microbiome in concert with the host immune system in the development of colitis-associated colorectal cancer (CAC). Some unique molecular differences occur in CAC, but their role in the pathogenesis and behavior of inflammation-associated cancers remains to be elucidated. Nonconventional types of dysplasia have been increasingly recognized, but their natural history is not well defined, and they have not been incorporated into surveillance algorithms. The concept of cumulative inflammatory burden highlights the importance of considering histologic inflammation over time as an important risk factor for CAC. Dysplasia is arguably the most important risk factor for developing CAC, and advances have been made in the endoscopic detection and removal of precancerous lesions, thereby deferring or avoiding surgical resection. Some of the agents used to treat IBD are chemopreventive. It is hoped that by gaining better control of the underlying inflammation with newer medications and better endoscopic detection and management, a more sophisticated appreciation of clinicopathologic risk factors, and growing awareness of the genetic, immunologic, and environmental causes of colitis- associated neoplasia, that colitis-associated colorectal neoplasia will become even more predictable and manageable in the coming years.

Detection of double-stranded DNA breaks and apoptosis induced by bleomycin in mouse intestine

The gastrointestinal tract is exposed to a myriad of mutagens, making the DNA damage response (DDR) essential to maintain intestinal homeostasis. In vivo models to study DDRs are necessary to understand the mechanisms of disease development caused by genetic disorders such as colorectal cancer. A double-stranded break (DSB) in DNA is the most toxic type of DNA damage; it can be induced by either X-rays or chemicals, including anticancer agents. If DSBs in DNA cannot be repaired, cells can die by apoptosis to be removed from tissues. Here, we show that the DDRs observed as the phosphorylation of H2AX (γH2AX) and caspase-3-dependent apoptosis-induction are under critical control in the intestine of C57BL mice that were injected intraperitoneally with bleomycin, a natural glycopeptide used clinically as an antitumor agent. We found a significant increase in γH2AX expression 2-6 hr post-treatment in mouse ileum, cecum, and colon tissues by Western blotting and immunostaining. Apoptotic cells were observed after 6-24 hr by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunofluorescence of active caspase-3. We observed that γH2AX expression and apoptotic cells were distributed in the lower part of the crypt. The experimental protocol described here is a simple procedure that can be used generally as an in vivo intestinal toxicity assay. Our experimental approach provides a useful method for examining the effects of various bioactive compounds on the DDR, which is essential for understanding intestinal homeostasis.

Bifidobacterium infantis Maintains Genome Stability in Ulcerative Colitis via Regulating Anaphase-Promoting Complex Subunit 7

Probiotics represents a promising intestinal microbiota-targeted therapeutic method for the treatment of ulcerative colitis (UC). Several lines of evidence implicate that Bifidobacterium infantis serves as a probiotic strain with proven efficacy in maintaining the remission of UC. However, the exact mechanisms underlying the beneficial effects of B. infantis on UC progression have yet to be elucidated. Herein, we provide evidence that B. infantis acts as a key predisposing factor for the maintenance of host genome stability. First, we showed that the fecal microbiota transplantation (FMT) of UC-derived feces contributes to more severely DNA damage in dextran sodium sulfate (DSS)-induced mice likely due to mucosa-associated microbiota alterations, as reflected by the rapid appearance of DNA double strand breaks (DSBs), a typical marker of genome instability. Genomic DNA damage analysis of colon tissues derived from healthy controls, patients with UC or dysplasia, and colitis associated cancer (CAC) patients, revealed an enhanced level of DSBs with aggravation in the degree of the intestinal mucosal lesions. To evaluate whether B. infantis modulates the host genome stability, we employed the DSS-induced colitis model and a TNFα-induced intestinal epithelial cell model. Following the administration of C57BL/6 mice with B. infantis via oral gavage, we found that the development of DSS-induced colitis in mice was significantly alleviated, in contrast to the colitis model group. Notably, B. infantis administration decreased DSB levels in both DSS-induced colitis and TNF-treated colonial cell model. Accordingly, our bioinformatic and functional studies demonstrated that B. infantis altered signal pathways involved in ubiquitin-mediated proteolysis, transcriptional misregulation in cancer, and the bacterial invasion of epithelial cells. Mechanistically, B. infantis upregulated anaphase-promoting complex subunit 7 (APC7), which was significantly suppressed in colitis condition, to activate the DNA repair pathway and alter the genome stability, while downregulation of APC7 abolished the efficiency of B. infantis treatment to induce a decrease in the level of DSBs in TNFα-induced colonial cells. Collectively, our results support that B. infantis orchestrates a molecular network involving in APC7 and genome stability, to control UC development at the clinical, biological, and mechanistic levels. Supplying B. infantis and targeting its associated pathway will yield valuable insight into the clinical management of UC patients.

Decreased IL-10 accelerates B-cell leukemia/lymphoma in a mouse model of pediatric lymphoid leukemia

B-cell deficiency and DNA damage in the bone marrow of Il10^−/− mice are associated with inflammation and mitigated by antibiotics.

In ETV6-RUNX1⁺Cdkn2a^−/− mice, low IL-10 accelerates the development of B-cell leukemia/lymphoma in a dose-dependent manner.

Exposures to a wide repertoire of common childhood infections and strong inflammatory responses to those infections are associated with the risk of pediatric B-cell acute lymphoblastic leukemia (B-ALL) in opposing directions. Neonatal inflammatory markers are also related to risk by unknown mechanism(s). Here, we demonstrate that interleukin-10 (IL-10) deficiency, which is associated with childhood B-ALL, indirectly impairs B lymphopoiesis and increases B-cell DNA damage in association with a module of 6 proinflammatory/myeloid-associated cytokines (IL-1α, IL-6, IL-12p40, IL-13, macrophage inflammatory protein-1β/CCL4, and granulocyte colony-stimulating factor). Importantly, antibiotics attenuated inflammation and B-cell defects in preleukemic Cdkn2a^−/−Il10^−/− mice. In an ETV6-RUNX1⁺ (E6R1⁺) Cdkn2a^−/− mouse model of B-ALL, decreased levels of IL-10 accelerated B-cell neoplasms in a dose-dependent manner and altered the mutational profile of these neoplasms. Our results illuminate a mechanism through which a low level of IL-10 can create a risk for leukemic transformation and support developing evidence that microbial dysbiosis contributes to pediatric B-ALL.

Curcumin Improves Epithelial Barrier Integrity of Caco-2 Monolayers by Inhibiting Endoplasmic Reticulum Stress and Subsequent Apoptosis

Curcumin is a natural polyphenol and is supposed to possess antioxidant, anti-inflammatory, anticancer, and antiapoptotic properties. Although some studies have reported the therapeutic effects of curcumin on ulcerative colitis (UC), the specific mechanism remains unclear. An in vitro coculture model of Caco-2 and differentiated THP-1 cells was established. After administration of curcumin (10 μM), Western blot analysis was performed to evaluate the protein levels of tight junction (TJ) proteins zonula occludens- (ZO-) 1 and claudin-1. Annexin V-APC/7-AAD assays and flow cytometry were conducted to assess Caco-2 cell apoptosis. The expression levels of oxidative stress and endoplasmic reticulum stress- (ERS-) related molecules were determined by Western blot analysis. Curcumin administration significantly upregulated ZO-1 and claudin-1 protein levels and reduced Caco-2 cell apoptosis. The protein levels of oxidative stress markers inducible nitric oxide synthase (iNOS) and γH2AX and ERS-induced apoptosis-related molecules C/EBP homologous protein (CHOP) and cleaved caspase-12 were significantly downregulated upon curcumin treatment. Furthermore, curcumin administration greatly blocked the protein kinase-like endoplasmic reticulum kinase- (PERK-) eukaryotic translation initiation factor 2α- (eIF2α-) activating transcription factor 4- (ATF4-) CHOP signaling pathway. Curcumin enhanced intestinal epithelial barrier integrity in the in vitro coculture model by upregulating TJ protein expressions and reducing intestinal epithelial cell apoptosis. The potential mechanisms may be suppression of ERS and subsequent apoptosis.

The Production and Function of Endogenous Interleukin-10 in Intestinal Epithelial Cells and Gut Homeostasis

The healthy gut is achieved and maintained through a balanced relationship between the mucosal immune system, microbial communities resident in the lumen, and the intestinal epithelium. The intestinal epithelium plays an exceptionally important role in harmonizing the interaction between the host immunity and the luminal residents, as this selectively permeable barrier separates but also allows interchange between the 2 environments. Interleukin (IL)-10 has been well established to play an important role in maintaining gut homeostasis by imparting diverse effects on a variety of cell types in this relationship. In the intestine, the source and the target of IL-10 include leukocytes and epithelial cells. Given that both the epithelium and IL-10 are essential players in supporting homeostasis, we discuss the relationship between these 2 factors, focusing on epithelial sources of IL-10 and the effects of IL-10 on the intestinal epithelium. Insight into this relationship reveals an important aspect of the innate immune function of intestinal epithelial cells.

PD-L1 upregulation is associated with activation of the DNA double-strand break repair pathway in patients with colitic cancer

Ulcerative colitis (UC) is a DNA damage-associated chronic inflammatory disease; the DNA double-strand break (DSB) repair pathway participates in UC-associated dysplasia/colitic cancer carcinogenesis. The DSB/interferon regulatory factor-1 (IRF-1) pathway can induce PD-L1 expression transcriptionally. However, the association of PD-L1/DSB/IRF-1 with sporadic colorectal cancer (SCRC), and UC-associated dysplasia/colitic cancer, remains elusive. Therefore, we investigated the significance of the PD-L1/DSB repair pathway using samples from 17 SCRC and 12 UC patients with rare UC-associated dysplasia/colitic cancer cases by immunohistochemical analysis. We compared PD-L1 expression between patients with SCRC and UC-associated dysplasia/colitic cancer and determined the association between PD-L1 and the CD8+ T-cell/DSB/IRF-1 axis in UC-associated dysplasia/colitic cancer. PD-L1 expression in UC and UC-associated dysplasia/colitic cancer was higher than in normal mucosa or SCRC, and in CD8-positive T lymphocytes in UC-associated dysplasia/colitic cancer than in SCRC. Moreover, PD-L1 upregulation was associated with γH2AX (DSB marker) and IRF-1 upregulation in UC-associated dysplasia/colitic cancer. IRF-1 upregulation was associated with γH2AX upregulation in UC-associated dysplasia/colitic cancer but not in SCRC. Multicolour immunofluorescence staining validated γH2AX/IRF-1/PD-L1 co-expression in colitic cancer tissue sections. Thus, immune cell-induced inflammation might activate the DSB/IRF-1 axis, potentially serving as the primary regulatory mechanism of PD-L1 expression in UC-associated carcinogenesis.

A Review of the Clinical Characteristics and Novel Molecular Subtypes of Endometrioid Ovarian Cancer

Ovarian cancer is one of the most common gynecologic cancers that has the highest mortality rate. Endometrioid ovarian cancer, a distinct subtype of epithelial ovarian cancer, is associated with endometriosis and Lynch syndrome, and is often accompanied by synchronous endometrial carcinoma. In recent years, dysbiosis of the microbiota within the female reproductive tract has been suggested to be involved in the pathogenesis of endometrial cancer and ovarian cancer, with some specific pathogens exhibiting oncogenic having been found to contribute to cancer development. It has been shown that dysregulation of the microenvironment and accumulation of mutations are stimulatory factors in the progression of endometrioid ovarian carcinoma. This would be a potential therapeutic target in the future. Simultaneously, multiple studies have demonstrated the role of four molecular subtypes of endometrioid ovarian cancer, which are of particular importance in the prediction of prognosis. This literature review aims to compile the potential mechanisms of endometrioid ovarian cancer, molecular characteristics, and molecular pathological types that could potentially play a role in the prediction of prognosis, and the novel therapeutic strategies, providing some guidance for the stratified management of ovarian cancer.

Model Complexity as Determining Factor for In Vitro Nanosafety Studies: Effects of Silver and Titanium Dioxide Nanomaterials in Intestinal Models

With the rising interest in the effects of orally ingested engineered nanomaterials (ENMs), much effort is undertaken to develop and advance intestinal in vitro models. The cytotoxic, proinflammatory, and DNA damaging properties of polyvinylpyrrolidone-capped silver (Ag-PVP) and titanium dioxide (TiO₂ , P25) ENM in four in vitro models of increasing complexity-from proliferating Caco-2 and HT29-MTX-E12 monocultures to long-term transwell triple cultures including THP-1 macrophages to reproduce the human intestine in healthy versus inflamed-like state-are studied. Results are compared against in vivo effects of the same ENM through intestinal tissue analysis from 28-day oral exposure studies in mice. Adverse responses are only observed in monocultures and suggest toxic potential for both ENM, typically showing stronger effects for Ag-PVP than for TiO₂ . By contrast, no adverse effects are observed in either the transwell cultures or the analyzed murine tissues. The data provide further support that monoculture models represent a cost and time efficient tool for early-phase hazard assessment. However, the observed similarities in morphology and ENM effects in murine intestinal tissue and the in vitro triple culture model suggest that advanced multifacetted research questions concerning oral ENM exposure are more adequately addressed by the more complex and time intensive models.

Amelioration of N,N'-dimethylhydrazine induced colon toxicity by epigallocatechin gallate in Wistar rats

Colon cancer is a life-threatening disease all over the world and is linked to constant oxidative stress and inflammation. Epigallocatechin gallate (EGCG), is a naturally occurring flavone possessing health benefiting pharmacological properties including antioxidant, anti-inflammatory and free radical scavenging properties. Our study investigates the role of EGCG on N,N'-dimethylhydrazine (DMH), a toxic environmental pollutant, induced colon toxicity. To investigate the effect of EGCG, Wistar rats were given EGCG for 7 days at the two doses of 10 and 20 mg/kg body weight and DMH was injected on the seventh day in all the group rats except the control. Our results indicate that DMH administration increased the oxidative stress (MDA) and depleted the glutathione and antioxidant enzyme activities (SOD, CAT, GR, GST and GPx) which was significantly ameliorated by EGCG treatment. Additionally DMH treatment upregulated inflammatory markers expression (NF-κB, COX-2 and IL-6) and enhanced mucosal damage in the colon. EGCG treatment significantly reduced inflammation and restored the normal histoarchitecture of the colon. We can conclude from the present study findings that EGCG protects the colon from DMH toxicity through its antioxidant and anti-inflammatory potential.

Paradoxical interaction between cancer and long-term postsepsis disorder: impairment of de novo carcinogenesis versus favoring the growth of established tumors

Background

Previous data have reported that the growth of established tumors may be facilitated by postsepsis disorder through changes in the microenvironment and immune dysfunction. However, the influence of postsepsis disorder in initial carcinogenesis remains elusive.

Methods

In the present work, the effect of postsepsis on inflammation-induced early carcinogenesis was evaluated in an experimental model of colitis-associated colorectal cancer (CAC). We also analyzed the frequency and role of intestinal T regulatory cells (Treg) in CAC carcinogenesis.

Results

The colitis grade and the tumor development rate were evaluated postmortem or in vivo through serial colonoscopies. Sepsis-surviving mice (SSM) presented with a lower colonic DNA damage, polyp incidence, reduced tumor load, and milder colitis than their sham-operated counterparts. Ablating Treg led to restoration of the ability to develop colitis and tumor polyps in the SSM, in a similar fashion to that in the sham-operated mice. On the other hand, the growth of subcutaneously inoculated MC38luc colorectal cancer cells or previously established chemical CAC tumors was increased in SSM.

Conclusion

Our results provide evidence that postsepsis disorder has a dual effect in cancer development, inhibiting inflammation-induced early carcinogenesis in a Treg-dependent manner, while increasing the growth of previously established tumors.

The food additive EDTA aggravates colitis and colon carcinogenesis in mouse models

Inflammatory bowel disease is a group of conditions with rising incidence caused by genetic and environmental factors including diet. The chelator ethylenediaminetetraacetate (EDTA) is widely used by the food and pharmaceutical industry among numerous other applications, leading to a considerable environmental exposure. Numerous safety studies in healthy animals have revealed no relevant toxicity by EDTA. Here we show that, in the presence of intestinal inflammation, EDTA is surprisingly capable of massively exacerbating inflammation and even inducing colorectal carcinogenesis at doses that are presumed to be safe. This toxicity is evident in two biologically different mouse models of inflammatory bowel disease, the AOM/DSS and the IL10^−/− model. The mechanism of this effect may be attributed to disruption of intercellular contacts as demonstrated by in vivo confocal endomicroscopy, electron microscopy and cell culture studies. Our findings add EDTA to the list of food additives that might be detrimental in the presence of intestinal inflammation, but the toxicity of which may have been missed by regulatory safety testing procedures that utilize only healthy models. We conclude that the current use of EDTA especially in food and pharmaceuticals should be reconsidered. Moreover, we suggest that intestinal inflammatory models should be implemented in the testing of food additives to account for the exposure of this primary organ to environmental and dietary stress.

Preventing Colitis-Associated Colon Cancer With Antioxidants: A Systematic Review

Inflammatory bowel disease (IBD) patients have an increased risk of developing colitis-associated colon cancer (CAC); however, the basis for inflammation-induced genetic damage requisite for neoplasia is unclear. Several studies have shown that IBD patients have signs of increased oxidative damage, which could be a result of genetic and environmental factors such as an excess in oxidant molecules released during chronic inflammation, mitochondrial dysfunction, a failure in antioxidant capacity, or oxidant promoting diets. It has been suggested that chronic oxidative environment in the intestine leads to the DNA lesions that precipitate colon carcinogenesis in IBD patients. Indeed, several preclinical and clinical studies show that different endogenous and exogenous antioxidant molecules are effective at reducing oxidation in the intestine. However, most clinical studies have focused on the short-term effects of antioxidants in IBD patients but not in CAC. This review article examines the role of oxidative DNA damage as a possible precipitating event in CAC in the context of chronic intestinal inflammation and the potential role of exogenous antioxidants to prevent these cancers.

A Novel PAK1-Notch1 Axis Regulates Crypt Homeostasis in Intestinal Inflammation

BACKGROUND & AIMS

p21-activated kinase-1 (PAK1) belongs to a family of serine-threonine kinases and contributes to cellular pathways such as nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Wingless-related integration site(Wnt)/β-catenin, all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to inflammatory bowel disease as well as colitis-associated cancer (CAC), and similarly was observed in interleukin (IL)10 knockout (KO) mice, a model of colitis and CAC. Here, we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL10 KO mice.

METHODS

IL10/PAK1 double-knockout (DKO) mice were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and periodic acid-Schiff. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480, and normal human colon epithelial cells 1CT.

RESULTS

When compared with IL10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyperproliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated up-regulation of the Notch1 target hairy and enhancer of split-1 and the stem cell receptor leucin-rich repeat-containing G-protein-coupled receptor 5 in DKO mice. Interestingly, the stem cell marker olfactomedin-4 was present in colonic tissue. Increased β-catenin messenger RNA and cytoplasmic accumulation indicated aberrant Wnt signaling. Co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation.

CONCLUSIONS

PAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1-Notch1 axis in intestinal pathophysiology of inflammatory bowel disease and CAC.

Crypt residing bacteria and proximal colonic carcinogenesis in a mouse model of Lynch syndrome

Colorectal cancer is a multifactorial disease involving inherited DNA mutations, environmental factors, gut inflammation and intestinal microbiota. Certain germline mutations within the DNA mismatch repair system are associated with Lynch syndrome tumors including right-sided colorectal cancer with mucinous phenotype and presence of an inflammatory infiltrate. Such tumors are more often associated with bacterial biofilms, which may contribute to disease onset and progression. Inflammatory bowel diseases are also associated with colorectal cancer and intestinal dysbiosis. Herein we addressed the question, whether inflammation can aggravate colorectal cancer development under mismatch repair deficiency. MSH2loxP/loxP Vill-cre mice were crossed into the IL-10-/- background to study the importance of inflammation and mucosal bacteria as a driver of tumorigenesis in a Lynch syndrome mouse model. An increase in large bowel tumorigenesis was found in double knockout mice both under conventional housing and under specific pathogen-free conditions. This increase was mostly due to the development of proximal tumors, a hotspot for tumorigenesis in Lynch syndrome, and was associated with a higher degree of inflammation. Additionally, bacterial invasion into the mucus of tumor crypts was observed in the proximal tumors. Inflammation shifted fecal and mucosal microbiota composition and was associated with enrichment in Escherichia-Shigella as well as Akkermansia, Bacteroides and Parabacteroides genera in fecal samples. Tumor-bearing double knockout mice showed a similar enrichment for Escherichia-Shigella and Parabacteroides. Lactobacilli, Lachnospiraceae and Muribaculaceae family members were depleted upon inflammation. In summary, chronic inflammation aggravates colonic tumorigenesis under mismatch repair deficiency and is associated with a shift in microbiota composition.

Targeting Gut Microbial Biofilms-A Key to Hinder Colon Carcinogenesis?

Colorectal cancer (CRC) is a global public health issue which poses a substantial humanistic and economic burden on patients, healthcare systems and society. In recent years, intestinal dysbiosis has been suggested to be involved in the pathogenesis of CRC, with specific pathogens exhibiting oncogenic potentials such as Fusobacterium nucleatum, Escherichia coli and enterotoxigenic Bacteroides fragilis having been found to contribute to CRC development. More recently, it has been shown that initiation of CRC development by these microorganisms requires the formation of biofilms. Gut microbial biofilm forms in the inner colonic mucus layer and is composed of polymicrobial communities. Biofilm results in the redistribution of colonic epithelial cell E-cadherin, increases permeability of the gut and causes a loss of function of the intestinal barrier, all of which enhance intestinal dysbiosis. This literature review aims to compile the various strategies that target these pathogenic biofilms and could potentially play a role in the prevention of CRC. We explore the potential use of natural products, silver nanoparticles, upconverting nanoparticles, thiosalicylate complexes, anti-rheumatic agent (Auranofin), probiotics and quorum-sensing inhibitors as strategies to hinder colon carcinogenesis via targeting colon-associated biofilms.

Limiting oxidative DNA damage reduces microbe-induced colitis-associated colorectal cancer

Inflammatory bowel disease patients have a greatly increased risk of developing colitis-associated colon cancer (CAC); however, the basis for inflammation-induced genetic damage requisite for neoplasia is unclear. Using three models of CAC, we find that sustained inflammation triggers 8-oxoguanine DNA lesions. Strikingly, antioxidants or iNOS inhibitors reduce 8-oxoguanine and polyps in CAC models. Because the mismatch repair (MMR) system repairs 8-oxoguanine and is frequently defective in colorectal cancer (CRC), we test whether 8-oxoguanine mediates oncogenesis in a Lynch syndrome (MMR-deficient) model. We show that microbiota generates an accumulation of 8-oxoguanine lesions in MMR-deficient colons. Accordingly, we find that 8-oxoguanine is elevated in neoplastic tissue of Lynch syndrome patients compared to matched untransformed tissue or non-Lynch syndrome neoplastic tissue. While antioxidants reduce 8-oxoguanine, they do not reduce CRC in Lynch syndrome models. Hence, microbe-induced oxidative/nitrosative DNA damage play causative roles in inflammatory CRC models, but not in Lynch syndrome models.

It is unclear how microbial-induced inflammation promotes neoplastic transformation in colitis-associated cancer (CAC). Here, the authors use models of CAC to show that inflammation induces 8-oxoguanine lesions in DNA, and that antioxidants can reduce these DNA lesions as well as CAC.

Nitro aspirin (NCX4040) induces apoptosis in PC3 metastatic prostate cancer cells via hydrogen peroxide (H2O2)-mediated oxidative stress

Non-steroidal anti-inflammatory drugs (NSAID) have shown promise as anticancer agents by inducing cell death apart from their antipyretic, anti-inflammatory and anti-thrombogenic effects. In our current study, we investigated the oxidative stress mediated cell death mechanism of a NSAID derivative NCX4040 (a nitric oxide (NO) releasing form of aspirin) in castration-resistant prostate cancer (CRPC) PC3 cell line. Our data revealed that NCX4040 is more potent than its parent compound aspirin or NO releasing compound DETA NONOate. NCX4040 significantly induced hydrogen peroxide formation with ensuing oxidative stress and mitochondrial depolarization resulting in lipid peroxidation, cell cycle arrest, inhibition of colony growth and induction of apoptosis in PC3 cells. Moreover, NCX4040 inhibited migration potential of PC3 cells by depolymerizing F-actin and promoting anoikis. Interestingly, elevated levels of NADPH oxidase 1 (NOX1), superoxide dismutase (SOD) 1 and 2 were observed upon NCX4040 treatment. However, down regulation of anti-apoptotic markers B-cell lymphoma 2 (Bcl2) and anti-oxidant thioredoxin reductase 1 (TXNRD1) expression were observed. In addition, NCX4040 down regulated cyclin D1 expression in PC3 cells further supporting the anticancer effect of NCX4040. Western blot analysis revealed that significant down regulation of key anti-apoptotic markers such as cellular inhibitor of apoptosis protein-1 (cIAP1), X-linked inhibitor of apoptosis (XIAP), survivin, and Cellular-Myc (c-Myc). On the other hand, NCX4040-treated cells showed upregulation of phosho histone H2AX (pH2AX), cleaved caspase3 and cleaved Poly [ADP-ribose] polymerase 1 (PARP1). Taken together, our data demonstrate that NCX4040 treatment enhances free radical formation which in turn induces oxidative stress leading to mitochondrial mediated cell death in metastatic PC3 cells.

AID, APOBEC3A and APOBEC3B efficiently deaminate deoxycytidines neighboring DNA damage induced by oxidation or alkylation

BACKGROUND

AID/APOBEC3 (A3) enzymes instigate genomic mutations that are involved in immunity and cancer. Although they can deaminate any deoxycytidine (dC) to deoxyuridine (dU), each family member has a signature preference determined by nucleotides surrounding the target dC. This WRC (W = A/T, R = A/G) and YC (Y = T/C) hotspot preference is established for AID and A3A/A3B, respectively. Base alkylation and oxidation are two of the most common types of DNA damage induced environmentally or by chemotherapy. Here we examined the activity of AID, A3A and A3B on dCs neighboring such damaged bases.

METHODS

Substrates were designed to contain target dCs either in normal WRC/YC hotspots, or in oxidized/alkylated DNA motifs. AID, A3A and A3B were purified and deamination kinetics of each were compared between substrates containing damaged vs. normal motifs.

RESULTS

All three enzymes efficiently deaminated dC when common damaged bases were present in the -2 or -1 positions. Strikingly, some damaged motifs supported comparable or higher catalytic efficiencies by AID, A3A and A3B than the WRC/YC motifs which are their most favored normal sequences. Based on the resolved interactions of AID, A3A and A3B with DNA, we modeled interactions with alkylated or oxidized bases. Corroborating the enzyme assay data, the surface regions that recognize normal bases are predicted to also interact robustly with oxidized and alkylated bases.

CONCLUSIONS

AID, A3A and A3B can efficiently recognize and deaminate dC whose neighbouring nucleotides are damaged.

GENERAL SIGNIFICANCE

Beyond AID/A3s initiating DNA damage, some forms of pre-existing damaged DNA can constitute favored targets of AID/A3s if encountered.

Anti-inflammatory activity of extensively hydrolyzed casein is mediated by granzyme B

OBJECTIVE

Nutritional factors such as extensively hydrolyzed casein (eHC) have been proposed to exert anti-inflammatory activity and affect clinical outcomes such as tolerance development in cow's milk allergy. Granzyme B (GrB) induces apoptosis in target cells and also controls the inflammatory response. Whether eHC could affect the activity of granzyme B and play a role in GrB-mediated inflammatory responses in vitro was unknown.

METHODS

The activity of GrB was measured using the substrate Ac-IEPD-pNA. Inflammatory responses were induced with GrB in HCT-8 and THP-1 cells, and pro-inflammatory cytokines were determined at the transcriptional and protein level.

RESULTS

GrB could induce the expression of IL-1β in HCT-8 cells, and IL-8 and MCP-1 in THP-1 cells, respectively. Interestingly, GrB acted synergistically on LPS-induced inflammation in HCT-8 cells and eHC reduced pro-inflammatory responses in both GrB and LPS-mediated inflammation. Further analyses revealed that eHC could inhibit the biological activities and cytotoxic activities of GrB and then could reduce GrB-mediated inflammatory response.

CONCLUSION

The results from the current study suggest that anti-inflammatory activity of extensively hydrolyzed casein is, to a certain extent, mediated through modulation of granzyme B activity and responses.

Nonenzymatic Serum Antioxidant Capacity in IBD and Its Association with the Severity of Bowel Inflammation and Corticosteroids Treatment

Background and objectives: Oxidative stress signalling plays a monumental role in inflammatory bowel disease (IBD). Reduction of oxidative stress might control inflammation, block tissue damage, and reverse natural history of IBD. We assessed the serum concentrations of free thiols (FT) and uric acid (SUA), together constituting a large part of nonenzymatic serum antioxidant capacity, as well as total antioxidant status (TAS) with reference to IBD phenotype, activity, co-occurrence of anemia, and treatment with azathioprine (AZA) and corticosteroids (CS). Additionally, we appraised the potential of uric acid, thiol stress, and TAS as mucosal healing (MH) markers in ulcerative colitis. Materials and methods: SUA, FT, and TAS were measured colorimetrically using, respectively, uricase, Ellman's and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods. Results: The study group consisted of 175 individuals: 57 controls, 71 ulcerative colitis (UC), and 47 Crohn's disease (CD) patients. When compared to controls, SUA levels were significantly lower in patients with CD, and FT and TAS levels were significantly lower in patients with CD and UC. In UC patients, SUA, FT, and TAS inversely correlated with the severity of bowel inflammation. As MH markers, SUA displayed better overall accuracy and higher specificity than FT. In active CD, FT, and SUA were significantly lower in patients with anemia. FT was significantly lower in patients treated with corticosteroids. Conclusions: IBD patients, regardless the disease phenotype, have systemic thiol stress, depleted total antioxidant capacity, and reduced concentrations of uric acid, reflecting, to various degrees, clinical and local disease activity as well as presence of anaemia, the most common extraintestinal manifestation of IBD. Evaluation of systemic total antioxidant status may be useful in noninvasive assessment of mucosal healing. Our findings on thiol stress provide an additional aspect on adverse effects of corticosteroids therapy.

Nonenzymatic Serum Antioxidant Capacity in IBD and Its Association with the Severity of Bowel Inflammation and Corticosteroids Treatment

Background and objectives: Oxidative stress signalling plays a monumental role in inflammatory bowel disease (IBD). Reduction of oxidative stress might control inflammation, block tissue damage, and reverse natural history of IBD. We assessed the serum concentrations of free thiols (FT) and uric acid (SUA), together constituting a large part of nonenzymatic serum antioxidant capacity, as well as total antioxidant status (TAS) with reference to IBD phenotype, activity, co-occurrence of anemia, and treatment with azathioprine (AZA) and corticosteroids (CS). Additionally, we appraised the potential of uric acid, thiol stress, and TAS as mucosal healing (MH) markers in ulcerative colitis. Materials and methods: SUA, FT, and TAS were measured colorimetrically using, respectively, uricase, Ellman’s and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods. Results: The study group consisted of 175 individuals: 57 controls, 71 ulcerative colitis (UC), and 47 Crohn’s disease (CD) patients. When compared to controls, SUA levels were significantly lower in patients with CD, and FT and TAS levels were significantly lower in patients with CD and UC. In UC patients, SUA, FT, and TAS inversely correlated with the severity of bowel inflammation. As MH markers, SUA displayed better overall accuracy and higher specificity than FT. In active CD, FT, and SUA were significantly lower in patients with anemia. FT was significantly lower in patients treated with corticosteroids. Conclusions: IBD patients, regardless the disease phenotype, have systemic thiol stress, depleted total antioxidant capacity, and reduced concentrations of uric acid, reflecting, to various degrees, clinical and local disease activity as well as presence of anaemia, the most common extraintestinal manifestation of IBD. Evaluation of systemic total antioxidant status may be useful in noninvasive assessment of mucosal healing. Our findings on thiol stress provide an additional aspect on adverse effects of corticosteroids therapy.

Mesalamine and azathioprine modulate junctional complexes and restore epithelial barrier function in intestinal inflammation

Disruption of mucosal structure and barrier function contribute to the pathogenesis of inflammatory bowel disease (IBD). Efficacy of therapy in IBD is based on endoscopic mucosal healing, which occurs by a dynamic interplay of epithelial cell regeneration, migration and differentiation. Both mesalamine (5-ASA) and azathioprine (AZTP) promote this process through mechanisms not clearly understood. We examined molecular pathways implicated in epithelial barrier function that were altered by 5-ASA and AZTP. Paracellular permeability induced by inflammatory mediators was mitigated by both compounds through restoration of cellular anchoring complexes. 5-ASA and AZTP induced rearrangement and membranous localization of junctional proteins and modulated genes involved in tight junctions. Intestinal organoids from wildtype-mice treated with TNF-α and IL-10- deficient-mice displayed impaired epithelial barrier with loss of membranous E-cadherin and reduced Desmoglein-2 expression. These effects were counteracted by 5-ASA and AZTP. Unlike AZTP that exhibited antiproliferative effects, 5-ASA promoted wound healing in colon epithelial cells. Both affected cellular senescence, cell cycle distribution and restricted cells in G1 or S phase without inducing apoptosis. This study provides mechanistic evidence that molecular actions of 5-ASA and AZTP on intestinal epithelia are fundamental in the resolution of barrier dysfunction.

Photoprotective Properties of Isothiocyanate and Nitrile Glucosinolate Derivatives From Meadowfoam (Limnanthes alba) Against UVB Irradiation in Human Skin Equivalent

Exposure to ultraviolet B (UVB) irradiation of the skin leads to numerous dermatological concerns including skin cancer and accelerated aging. Natural product glucosinolate derivatives, like sulforaphane, have been shown to exhibit chemopreventive and photoprotective properties. In this study, we examined meadowfoam (Limnanthes alba) glucosinolate derivatives, 3-methoxybenzyl isothiocyanate (MBITC) and 3-methoxyphenyl acetonitrile (MPACN), for their activity in protecting against the consequences of UV exposure. To that end, we have exposed human primary epidermal keratinocytes (HPEKs) and 3D human skin reconstructed in vitro (EpiDerm^TM FT-400) to UVB insult and investigated whether MBITC and MPACN treatment ameliorated the harmful effects of UVB damage. Activity was determined by the compounds’ efficacy in counteracting UVB-induced DNA damage, matrix-metalloproteinase (MMP) expression, and proliferation. We found that in monolayer cultures of HPEK, MBITC and MPACN did not protect against a UVB-induced loss in proliferation and MBITC itself inhibited cell proliferation. However, in human reconstructed skin-equivalents, MBITC and MPACN decrease epidermal cyclobutane pyrimidine dimers (CPDs) and significantly reduce total phosphorylated γH2A.X levels. Both MBITC and MPACN inhibit UVB-induced MMP-1 and MMP-3 expression indicating their role to prevent photoaging. Both compounds, and MPACN in particular, showed activity against UVB-induced proliferation as indicated by fewer epidermal PCNA+ cells and prevented UVB-induced hyperplasia as determined by a reduction in reconstructed skin epidermal thickness (ET). These data demonstrate that MBITC and MPACN exhibit promising anti-photocarcinogenic and anti-photoaging properties in the skin microenvironment and could be used for therapeutic interventions.