FA-97, a New Synthetic Caffeic Acid Phenethyl Ester Derivative, Ameliorates DSS-Induced Colitis Against Oxidative Stress by Activating Nrf2/HO-1 Pathway

Sodium butyrate alleviates experimental autoimmune prostatitis by inhibiting oxidative stress and NLRP3 inflammasome activation via the Nrf2/HO-1 pathway

BACKGROUND

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) leads to severe discomfort in males and loss of sperm quality. Current therapeutic options have failed to achieve satisfactory results. Sodium butyrate (NaB) plays a beneficial role in reducing inflammation, increasing antioxidant capacities, and improving organ dysfunction; additionally NaB has good safety prospects and great potential for clinical application. The purpose of the current research was to study the effect of NaB on CP/CPPS and the underlying mechanisms using a mouse model of experimental autoimmune prostatitis (EAP) mice.

METHODS

The EAP mouse model was successfully established by subcutaneously injecting a mixture of prostate antigen and complete Freund's adjuvant. Then, EAP mice received daily intraperitoneal injections of NaB (100, 200, or 400 mg/kg/day) for 16 days, from Days 26 to 42. We then explored anti-inflammatory potential mechanisms of NaB by studying the effects of Nrf2 inhibitor ML385 and HO-1 inhibitor zinc protoporphyrin on prostate inflammation and pelvic pain using this model. On Day 42, hematoxylin-eosin staining and dihydroethidium staining were used to evaluate the histological changes and oxidative stress levels of prostate tissues. Chronic pelvic pain was assessed by applying Von Frey filaments to the lower abdomen. The levels of inflammation-related cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor were detected by enzyme-linked immunosorbent assay. The regulation of Nrf2/HO-1 signaling pathway and the expression of NLRP3 inflammasome-related protein in EAP mice were detected by western blot analysis assay.

RESULTS

Compared with the EAP group, chronic pain development, histological manifestations, and cytokine levels showed that NaB reduced the severity of EAP. NaB treatment could inhibit NLRP3 inflammasome activation. Mechanism studies showed that NaB intervention could alleviate oxidative stress in EAP mice through Nrf2/HO-1 signal pathway. Nrf2/HO-1 pathway inhibitors can inhibit NaB -mediated oxidative stress. The inhibitory effect of NaB on the activation of NLRP3 inflammasome and anti-inflammatory effect can also be blocked by Nrf2/HO-1 pathway.

CONCLUSIONS

NaB treatment can alleviates prostatic inflammation and pelvic pain associated with EAP by inhibiting oxidative stress and NLRP3 inflammasome activation via the Nrf2/HO-1 pathway. NaB has the potential as an effective agent in the treatment of EAP.

Therapeutic effects of genistein in experimentally induced ulcerative colitis in rats via affecting mitochondrial biogenesis

Ulcerative colitis (UC) is an inflammatory bowel disease that affects the mucosa of the colon, resulting in severe inflammation and ulcers. Genistein is a polyphenolic isoflavone present in several vegetables, such as soybeans and fava beans. Therefore, we conducted the following study to determine the therapeutic effects of genistein on UC in rats by influencing antioxidant activity and mitochondrial biogenesis and the subsequent effects on the apoptotic pathway. UC was induced in rats by single intracolonic administration of 2 ml of 4% acetic acid. Then, UC rats were treated with 25-mg/kg genistein. Colon samples were obtained to assess the gene and protein expression of nuclear factor erythroid 2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor-gamma coactivator (PGC-1), mitochondrial transcription factor A (TFAM), B-cell lymphoma 2 (BCL2), BCL2-associated X (BAX), caspase-3, caspase-8, and caspase-9. In addition, colon sections were stained with hematoxylin/eosin to investigate the cell structure. The microimages of UC rats revealed inflammatory cell infiltration, hemorrhage, and the destruction of intestinal glands, and these effects were improved by treatment with genistein. Finally, treatment with genistein significantly increased the expression of PGC-1, TFAM, Nrf2, HO-1, and BCL2 and reduced the expression of BAX, caspase-3, caspase-8, and caspase-9. In conclusion, genistein exerted therapeutic effects against UC in rats. This therapeutic activity involved enhancing antioxidant activity and increasing mitochondrial biogenesis, which reduced cell apoptosis.

Agaricus blazei Polysaccharide Alleviates DSS-Induced Colitis in Mice by Modulating Intestinal Barrier and Remodeling Metabolism

Ulcerative colitis (UC) is a chronic noninfectious intestinal disease that severely affects patients' quality of life. Agaricus blazei Murrill polysaccharide (ABP) is an effective active ingredient extracted from Agaricus blazei Murrill (ABM). It has good efficacy in inhibiting tumor cell growth, lowering blood pressure, and improving atherosclerosis. However, its effect on colitis is unclear. The aim of this study was to analyze the protective effects and potential mechanisms of ABP against dextran sulfate sodium (DSS)-induced acute colitis in mice. The results showed that dietary supplementation with ABP significantly alleviated DSS-induced colitis symptoms, inflammatory responses, and oxidative stress. Meanwhile, ABP intervention was able to maintain the integrity of the intestinal mechanical barrier by promoting the expression of ZO-1 and Occludin tight junction proteins and facilitating mucus secretion. Moreover, 16S rRNA sequencing results suggested that ABP intervention was able to alleviate DSS-induced gut microbiota disruption, and nontargeted metabolomics results indicated that ABP was able to remodel metabolism. In conclusion, these results demonstrate that dietary supplementation with ABP alleviated DSS-induced acute colitis by maintaining intestinal barrier integrity and remodeling metabolism. These results improve our understanding of ABP function and provide a theoretical basis for the use of dietary supplementation with ABP for the prevention of ulcerative colitis.

Role of extracted phytochemicals from Rosa sterilis S. D. Shi in DSS-induced colitis mice: potential amelioration of UC

Rosa sterilis S. D. Shi is a new variety of R. roxburghii Tratt and its fruits are rich in bioactive components, but its effects and mechanisms against intestinal inflammation are currently unknown. In this study, the main components of the ethanol extract of R. sterilis S. D. Shi fruits (RSE) were identified and its anti-inflammatory efficacy in DSS-induced mice was evaluated. A total of nine compounds were identified, including 1-O-E-cinnamoyl-(6-arabinosylglucose), ellagic acid-O-rhamnoside, (epi) catechin, niga-ichigoside F1, etc. The results demonstrated that RSE ameliorated DSS-induced inflammation in mouse colon tissues by increasing mucin expression, reducing the production of TNF-α, IL-1β, and IL-6, inhibiting the mRNA expression of COX-2 and iNOS, regulating the composition of gut microbiota through suppressing Escherichia-Shigella while increasing Akkermansia muciniphila, and promoting the production of SCFAs, especially acetic acid. Briefly, RSE showed outstanding potential for anti-inflammatory activity and is expected to be a promising dietary supplement for healthy individuals to prevent or relieve colitis and colitis-related diseases, which provided a new direction for functional food development.

Omentin-1 ameliorates experimental inflammatory bowel disease via Nrf2 activation and redox regulation

AIMS

Omentin-1 production is decreased in patients with IBD. However, the specific role of Omentin-1 in IBD has not been fully elucidated. This study aimed to investigate the expression and role of Omentin-1 in IBD and the potential mechanisms.

MAIN METHODS

We collected human serum and colon biopsy samples at the Wuhan Union Hospital. Omentin-1 recombinant protein was injected intraperitoneally in a DSS-induced experimental IBD mouse model. Omentin-1 levels were measured in IBD patients, colitis mice, and LPS-induced HT-29 cells. Omentin-1 and/or a Nrf2 specific inhibitor (ML385) were administered to DSS mice and LPS-induced HT-29 cells. The effects of Omentin-1 on inflammation, intestinal barrier function, Nrf2 pathway, oxidative stress, and NF-κB signaling were detected in vivo and in vitro.

KEY FINDINGS

Serum Omentin-1 levels were significantly reduced in UC and CD patients compared with controls (173.7 (IQR, 120.1-221.2) ng/ml, 80.8 (43.8-151.8) ng/ml, and 270.7 (220.7-306.5) ng/ml, respectively). The levels of Omentin-1 were also significantly lower in colitis mice and LPS-induced HT-29 cells. Omentin-1 treatment effectively ameliorated inflammation and impaired intestinal barrier, decreased ROS and MDA levels, and increased GSH and SOD production in the DSS-induced colitis mice and LPS-induced HT-29 cells. Mechanically, Omentin-1 repaired the intestinal barrier by activating Nrf2, then improving oxidative stress and inhibiting NF-κB signaling. Furthermore, the interaction between Omentin-1 and Nrf2 was identified.

SIGNIFICANCE

Omentin-1 activates the Nrf2 pathway to regulate redox balance, ultimately protecting intestinal barrier function and reducing intestinal inflammation. In general, Omentin-1 can be used as a promising therapeutic target for IBD.

Biological Activities of p-Hydroxycinnamic Acids in Maintaining Gut Barrier Integrity and Function

It is well established that p-Hydroxycinnamic acids (HCAs), including ferulic, caffeic, sinapic, and p-coumaric acids, possess a characteristic phenylpropanoid C6-C3 backbone and account for about one-third of the phenolic compounds in our diet. HCAs are typically associated with various plant cell wall components, including mono-, di-, and polysaccharides, sterols, polyamines, glycoproteins, and lignins. Interestingly, enzymes produced by intestinal microbes liberate HCAs from these associations. HCAs are completely absorbed in their free form upon ingestion and undergo specific reactions upon absorption in the small intestine or liver. The gut epithelium, composed of intestinal epithelial cells (IECs), acts as a physical barrier against harmful bacteria and a site for regulated interactions between bacteria and the gut lumen. Thus, maintaining the integrity of the epithelial barrier is essential for establishing a physiochemical environment conducive to homeostasis. This review summarizes the protective effects of HCAs on the intestinal barrier, achieved through four mechanisms: preserving tight junction proteins (TJPs), modulating pro-inflammatory cytokines, exerting antioxidant activity, and regulating the intestinal microbiota.

Network Pharmacology Study of Bioactive Components and Molecular Mechanisms of the Glycoside Fraction from Picrorhiza scrophulariiflora Against Experimental Colitis

Purpose

To explore the potential mechanism of glycosidic fraction of Picrorhiza scrophulariiflora Pennell (GPS) extract for the treatment of colitis using UPLC-QTOF-MS analysis, network pharmacology and experimental research.

Methods

The active components of GPS extract were identified by UPLC-QTOF-MS analysis and extracted their targets from the databases, which was used for network pharmacology analysis. Kyoto Encyclopedia of genes and genomes (KEGG) pathway analysis was performed to discover potential therapeutic mechanisms, and the network pharmacology results were then validated by in vivo and in vitro experiments.

Results

The results showed that GPS extract significantly alleviated the clinical signs of colitis, including body weight, disease activity index, colon shortening, and colon tissue damage, and inhibited the transcription and production of colonic IL-1β and IL-6 in DSS-induced colitis mice. In vitro, GPS extract also significantly suppressed nitric oxide (NO) production, iNOS expression, IL-1β and IL-6 transcription of LPS-activated RAW 264.7 cells. Network pharmacology integrated with experimental validation identified that GPS extract significantly suppressed Akt, p38, ERK, and JNK phosphorylation in vivo and in vitro, and luteolin, apocynin, caffeic acid, caffeic acid methyl ester, luteoloside, picroside II, aucubin, cinnamic acid, vanillic acid, and sweroside were the main components responsible for the anti-inflammatory effect of GPS. These findings demonstrate that the potential anti-inflammatory effect of GPS extract against colitis is achieved through suppressing PI3K/Akt and MAPK pathways, and that the abovementioned active components mainly exerted its anti-inflammatory effect.

Conclusion

The therapeutic effect of GPS extract on colitis is related to PI3K/Akt and MAPK pathways, which is a promising remedy for colitis therapy.

Geniposide ameliorates dextran sulfate sodium-induced ulcerative colitis via KEAP1-Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The dried fruit of Gardenia jasminoides Ellis (Zhizi in Chinese) is a traditional medicine used for thousands of years in China, Japan and Korea. Zhizi was recorded in Shennong Herbal, as a folk medicine, it reduces fever and treats gastrointestinal disturbance with antiphlogistic effects. Geniposide, an iridoid glycoside, is an important bioactive compound derived from Zhizi and possesses remarkable antioxidant and anti-inflammatory capacities. The pharmacological efficacy of Zhizi is highly related to the antioxidant and anti-inflammatory effects of geniposide.

AIM OF THE STUDY

Ulcerative colitis (UC) is a common chronic gastrointestinal disease as a global public health threat. Redox imbalance is an essential factor in the progression and recurrence of UC. This study aimed to explore the therapeutic effect of geniposide on colitis and uncover the underlying mechanisms of geniposide-mediated antioxidant and anti-inflammatory activities.

EXPERIMENTAL DESIGN

The study design involved investigating the novel mechanism by which geniposide ameliorates dextran sulfate sodium (DSS)-induced colitis in vivo and lipopolysaccharide (LPS)-challenged colonic epithelial cells in vitro.

MATERIALS AND METHODS

The protective effect of geniposide against colitis was evaluated by histopathologic observation and biochemical analysis of colonic tissues in DSS-induced colitis mice. The antioxidant and anti-inflammatory effects of geniposide were evaluated in both DSS-induced colitis mice and LPS-challenged colonic epithelial cells. Immunoprecipitation, drug affinity responsive target stability (DARTS), and molecular docking were performed to identify the potential therapeutic target of geniposide and the potential binding sites and patterns.

RESULTS

Geniposide ameliorated the symptoms of DSS-induced colitis and colonic barrier injury, inhibited pro-inflammatory cytokine expression, and suppressed activation of the NF-κB signaling in colonic tissues of DSS-challenged mice. Geniposide also ameliorated lipid peroxidation and restored redox homeostasis in DSS-treated colonic tissues. In addition, in vitro experiments also showed that geniposide exhibited significant anti-inflammatory and antioxidant activity, as evidenced by suppressed IκB-α and p65 phosphorylation and IκB-α degradation, and enhanced the phosphorylation and transcriptional activity of Nrf2 in LPS-treated Caco2 cells. ML385, a specific Nrf2 inhibitor, abolished the protective effect of geniposide against LPS-induced inflammation. Mechanistically, geniposide could bind to KEAP1, thereby disrupting the interaction between KEAP1 and Nrf2, preventing Nrf2 from degradation and activating the Nrf2/ARE signaling pathway, ultimately suppressing the onset of inflammation caused by redox imbalance.

CONCLUSIONS

Geniposide ameliorates colitis by activation of Nrf2/ARE signaling, while preventing colonic redox imbalance and inflammatory damage, indicating that geniposide can be considered as a promising lead compound for the treatment of colitis.

Sodium Butyrate Inhibits Oxidative Stress and NF-κB/NLRP3 Activation in Dextran Sulfate Sodium Salt-Induced Colitis in Mice with Involvement of the Nrf2 Signaling Pathway and Mitophagy

BACKGROUND

Sodium butyrate (NaB) is a short-chain fatty acid produced by intestinal microbial fermentation of dietary fiber, and has been shown to be effective in inhibiting ulcerative colitis (UC). However, how NaB regulates inflammation and oxidative stress in the pathogenesis of UC is not clear.

AIMS

The purpose of this study was to use a dextran sulfate sodium salt (DSS)-induced murine colitis model, and determine the effects of NaB and the related molecular mechanisms.

METHODS

Colitis model was induced in mice by administration of 2.5%(wt/vol) DSS. 0.1 M NaB in drinking water, or intraperitoneal injection of NaB (1 g/kg body weight) was given during the study period. In vivo imaging was performed to detect abdominal reactive oxygen species (ROS). Western blotting and RT-PCR were used to determine the levels of target signals.

RESULTS

The results showed that NaB decreases the severity of colitis as determined by an improved survival rate, colon length, spleen weight, disease activity index (DAI), and histopathological changes. NaB reduced oxidative stress as determined by a reduction in abdominal ROS chemiluminescence signaling, inhibition of the accumulation of myeloperoxidase and malondialdehyde, and restoration of glutathione activity. NaB activated the COX-2/Nrf2/HO-1 pathway by increasing the expressions of COX-2, Nrf2, and HO-1 proteins. NaB inhibited the phosphorylation of NF-κB and activation of NLRP3 inflammasomes, and reduced the secretion of corresponding inflammatory factors. Furthermore, NaB promoted the occurrence of mitophagy via activating the expression of Pink1/Parkin.

CONCLUSIONS

In conclusion, our results indicate that NaB improves colitis by inhibiting oxidative stress and NF-κB/NLRP3 activation, which may be via COX-2/Nrf2/HO-1 activation and mitophagy.

Sinigrin Attenuates the Dextran Sulfate Sodium-induced Colitis in Mice by Modulating the MAPK Pathway

Ulcerative colitis (UC) is an intestinal inflammatory disease characterised by the loss of intestinal crypts, edema, mucosal ulceration, and infiltration of inflammatory cells in the mucosa. The current study aimed to investigate the protective and therapeutic effects of sinigrin and underlying mechanisms in a dextran sulfate sodium (DSS)-induced mouse model of ulcerative colitis. DSS-induced colitis models were used to demonstrate sinigrin's therapeutic/protective action. Mice were orally administered with sinigrin (15 mg/kg or 30 mg/kg) for a period of 12 days in both prophylactic and therapeutic models. Animal weights, stool consistency, and bleeding parameters were measured throughout the experimental period. After the experimental period, colon lengths were measured, and colon tissues were harvested to determine the levels of oxidative stress-inducing factors (nitrates and MDA levels) and anti-oxidant components (GSH, SOD, and catalase). Furthermore, gene expression analysis, IL-17 levels, and inflammatory marker expressions were measured using RT-qPCR, ELISA, and immunohistochemical methods respectively. Furthermore, histopathological observations and elucidation of the mechanism of action were determined using H&E analysis and Western blot analysis. Sinigrin treatment (in both prophylactic and therapeutic models) significantly mitigated the DSS-induced body weight loss, attenuated the colon length shrinkage, and improved the disease index score (p < 0.001). Further results revealed that sinigrin's protective/therapeutic effect is associated with a significant attenuation of pro‑inflammatory cytokine production (p < 0.001), reversing the anti-oxidant enzyme levels (p < 0.001) and substantial improvement (2 folds) of the disruption of the colonic morphology in colon tissues compared to DSS control. Immunohistochemical analysis showed that sinigrin treatment remarkably reduced the DSS-induced myeloperoxidase, neutrophil elastase, and CD68 expression in colon tissues. Additionally, sinigrin successfully abrogated the DSS-induced IL-17 levels (p < 0.001) and improved the colonic barrier in colon tissues. Overall, these results demonstrated that sinigrin exerts protective and therapeutic effects on DSS‑induced colitis, by enhancing the anti-oxidant enzymes and suppressing the intestinal inflammatory cascade of markers by regulating the MAPK pathway.

Suppression of microRNA-222-3p ameliorates ulcerative colitis and colitis-associated colorectal cancer to protect against oxidative stress via targeting BRG1 to activate Nrf2/HO-1 signaling pathway

Oxidative stress is an important pathogenic factor in ulcerative colitis (UC) and colitis-associated colorectal cancer (CAC), further impairing the entire colon. Intestinal epithelial cells (IECs) are crucial components of innate immunity and play an important role in maintaining intestinal barrier function. Recent studies have indicated that microRNA-222-3p (miR-222-3p) is increased in colon of UC and colorectal cancer (CRC) patients, and miR-222-3p is a crucial regulator of oxidative stress. However, whether miR-222-3p influences IEC oxidative stress in UC and CAC remains unknown. This study investigated the effect of miR-222-3p on the regulation of IEC oxidative stress in UC and CAC. An in vitro inflammation model was established in NCM460 colonic cells, mouse UC and CAC models were established in vivo, and IECs were isolated. The biological role and mechanism of miR-222-3p-mediated oxidative stress in UC and CAC were determined. We demonstrated that miR-222-3p expression was notably increased in dextran sulfate sodium (DSS)-induced NCM460 cells and IECs from UC and CAC mice. In vitro, these results showed that the downregulation of miR-222-3p reduced oxidative stress, caspase-3 activity, IL-1β and TNF-α in DSS-induced NCM460 cells. We further identified BRG1 as the target gene of miR-222-3p, and downregulating miR-222-3p alleviated DSS-induced oxidative injury via promoting BRG1-mediated activation Nrf2/HO-1 signaling in NCM460 cells. The in vivo results demonstrated that inhibiting miR-222-3p in IECs significantly relieved oxidative stress and inflammation in the damaged colons of UC and CAC mice, as evidenced by decreases in ROS, MDA, IL-1β and TNF-α levels and increases in GSH-Px levels. Our study further demonstrated that inhibiting miR-222-3p in IECs attenuated oxidative damage by targeting BRG1 to activate the Nrf2/HO-1 signaling. In summary, inhibiting miR-222-3p in IECs attenuates oxidative stress by targeting BRG1 to activate the Nrf2/HO-1 signaling, thereby reducing colonic inflammation and tumorigenesis.

Fuc-S-A New Ultrasonic Degraded Sulfated α-l-Fucooligosaccharide-Alleviates DSS-Inflicted Colitis through Reshaping Gut Microbiota and Modulating Host-Microbe Tryptophan Metabolism

SCOPE

The dysbiosis of intestinal microecology plays an important pathogenic role in the development of inflammatory bowel disease.

METHODS AND RESULTS

A polysaccharide named Fuc-S, with a molecular weight of 156 kDa, was prepared by the ultrasonic degradation of fucoidan. Monosaccharide composition, FTIR, methylation, and NMR spectral analysis indicated that Fuc-S may have a backbone consisting of →3)-α-L-Fucp-(1→, →4)-α-L-Fucp-(1→ and →3, 4)-α-D-Glcp-(1→. Moreover, male C57BL/6 mice were fed three cycles of 1.8% dextran sulfate sodium (DSS) for 5 days and then water for 7 days to induce colitis. The longitudinal microbiome alterations were evaluated using 16S amplicon sequencing. In vivo assays showed that Fuc-S significantly improved clinical manifestations, colon shortening, colon injury, and colonic inflammatory cell infiltration associated with DSS-induced chronic colitis in mice. Further studies revealed that these beneficial effects were associated with the inhibition of Akt, p-38, ERK, and JNK phosphorylation in the colon tissues, regulating the structure and abundance of the gut microbiota, and modulating the host-microbe tryptophan metabolism of the mice with chronic colitis.

CONCLUSION

Our data confirmed the presence of glucose in the backbone of fucoidan and provided useful information that Fuc-S can be applied as an effective functional food and pharmaceutical candidate for IBD treatment.

The Alleviation of Dextran Sulfate Sodium (DSS)-Induced Colitis Correlate with the logP Values of Food-Derived Electrophilic Compounds

Food-derived electrophilic compounds (FECs) are small molecules with electrophilic groups with potential cytoprotective effects. This study investigated the differential effects of six prevalent FECs on colitis in dextran sodium sulfate (DSS)-induced mice and the underlying relationship with molecular characteristics. Fumaric acid (FMA), isoliquiritigenin (ISO), cinnamaldehyde (CA), ferulic acid (FA), sulforaphane (SFN), and chlorogenic acid (CGA) exhibited varying improvements in colitis on clinical signs, colonic histopathology, inflammatory and oxidative indicators, and Nrf2 pathway in a sequence of SFN, ISO > FA, CA > FMA, CGA. Representative molecular characteristics of the “penetration-affinity−covalent binding” procedure, logP value, Keap1 affinity energy, and electrophilic index of FECs were theoretically calculated, among which logP value revealed a strong correlation with colitis improvements, which was related to the expression of Nrf2 and its downstream proteins. Above all, SFN and ISO possessed high logP values and effectively improving DSS-induced colitis by activating the Keap1−Nrf2 pathway to alleviate oxidative stress and inflammatory responses.

Total terpenoids of Inula japonica activated the Nrf2 receptor to alleviate the inflammation and oxidative stress in LPS-induced acute lung injury

BACKGROUND

Acute lung injury (ALI) is a life-threatening lung disease and characterized by pulmonary edema and atelectasis. Inula japonica Thunb. is a commonly used traditional Chinese medicine for the treatment of lung diseases. However, the potential effect and mechanism of total terpenoids of I. japonica (TTIJ) on ALI remain obscure.

PURPOSE

This study focused on the protective effect of TTIJ on lipopolysaccharide (LPS)-induced ALI in mice and its potential mechanism.

STUDY DESIGN AND METHODS

A mouse model of ALI was established by intratracheal instillation of LPS to investigate the protective effect of TTIJ. RNA-seq and bioinformatics were then performed to reveal the underlying mechanism. Finally, western blot and real-time qPCR were used to verify the effects of TTIJ on the inflammation and oxidative stress.

RESULTS

TTIJ notably attenuated LPS-induced histopathological changes of lung. The RNA-seq result suggested that the protective effect of TTIJ on LPS-induced ALI were associated with the Toll-like receptor 4 (TLR4) and nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling pathways. Pretreatment with TTIJ significantly reduced the inflammation and oxidative stress via regulating levels of pro-inflammatory and anti-oxidative cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), superoxide dismutase (SOD), and glutathione (GSH), in LPS-induced ALI mice. TTIJ treatment could suppress the cyclooxygenase-2 (COX-2) expression level and the phosphorylation of p65, p38, ERK, and JNK through the inactivation of the MAPK/NF-κB signaling pathway in a TLR4-independent manner. Meanwhile, TTIJ treatment upregulated expression levels of proteins involved in the Nrf2 signaling pathway, such as heme oxygenase-1 (HO-1), NAD(P)H: quinoneoxidoreductase-1 (NQO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM), via activating the Nrf2 receptor, which was confirmed by the luciferase assay.

CONCLUSION

TTIJ could activate the Nrf2 receptor to alleviate the inflammatory response and oxidative stress in LPS-induced ALI mice, which suggested that TTIJ could serve as the potential agent in the treatment of ALI.

Curative effects of fucoidan on acetic acid induced ulcerative colitis in rats via modulating aryl hydrocarbon receptor and phosphodiesterase-4

Background

Ulcerative colitis (UC) is an inflammatory bowel disease. Fucoidan, sulfated polysaccharide of brown seaweed, demonstrates various pharmacological actions as anti-inflammatory, anti-tumor and anti-bacterial effects. Therefore, we opt to investigate the potential curative effects of fucoidan in experimentally induced UC in rats through modulating aryl hydrocarbon receptor (AhR), phosphodiesterase-4 (PDE4), nuclear factor erythroid 2-related factor 2 (Nrf2) and Heme Oxygenase-1 (HO-1).

Methods

UC was induced in rats using intracolonic 2 ml of 4% acetic acid. Some rats were treated with 150 mg/kg fucoidan. Samples of colon were used to investigate gene and protein expression of AhR, PDE4, Nrf2, HO-1 and cyclic adenosine monophosphate (cAMP). Sections of colon were stained with hematoxylin/eosin, Alcian blue or immune-stained with anti-PDE4 antibodies.

Results

Investigation of hematoxylin/eosin stained micro-images of UC rats revealed damaged intestinal glands, severe hemorrhage and inflammatory cell infiltration, while sections stained with Alcian Blue revealed damaged and almost absent intestinal glands. UC results in elevated gene and protein expression of PDE4 associated with reduced gene and protein expression of AhR, IL-22, cAMP, Nrf2 and HO-1. Finally, UC increased the oxidative stress and reduced antioxidant activity in colon tissues. All morphological changes as well as gene and protein expressions were ameliorated by fucoidan.

Conclusion

Fucoidan could treat UC induced in rats. It restored the normal weight and length of colon associated with morphological improvement as found by examining sections stained with hematoxylin/eosin and Alcian Blue. The curative effects could be explained by enhancing antioxidant activity, reducing the expression of PDE4 and increasing the expression of AhR, IL-22 and cAMP.

Therapeutic effects of sulforaphane in ulcerative colitis: effect on antioxidant activity, mitochondrial biogenesis and DNA polymerization

Objectives

Ulcerative colitis (UC), an inflammatory bowel disease, affects mucosal lining of colon leading to inflammation and ulcers. Sulforaphane is a natural compound obtained from cruciferous vegetables. We aimed to investigate potential therapeutic effects of sulforaphane in experimentally induced UC in rats through affection antioxidant activity, mitochondrial biogenesis and DNA polymerization.

Methods

UC was induced in rats via an intracolonic single administration of 2 ml of 4% acetic acid. UC rats were treated with 15 mg/kg sulforaphane. Samples of colon were used to investigate gene expression and protein levels of peroxisome proliferator-activated receptor-gamma coactivator (PGC-1), mitochondrial transcription factor A (TFAM), mammalian target of rapamycin (mTOR), cyclin D1, nuclear factor erythroid 2-related factor-2 (Nrf2), heme Oxygenase-1 (HO-1) and proliferating cell nuclear antigen (PCNA).

Results

UC showed dark distorted Goblet cell nucleus with disarranged mucus granules and no distinct brush border with atypical microvilli. All morphological changes were improved by treating with sulforaphane. Finally, treatment with sulforaphane significantly increased expression of PGC-1, TFAM, Nrf2 and HO-1 associated with reduction in expression of mTOR, cyclin D1 and PCNA.

Conclusion

Sulforaphane could cure UC in rats. The protective activity can be explained by enhancing antioxidant activity, elevating mitochondrial biogenesis and inhibiting DNA polymerization.

Gingerenone A Alleviates Ferroptosis in Secondary Liver Injury in Colitis Mice via Activating Nrf2-Gpx4 Signaling Pathway

Patients with ulcerative colitis (UC) have been found to be frequently associated with secondary liver injury (SLI). In this study, we investigated the protective effect of GA on dextran sodium sulfate (DSS)-induced SLI in mice and its mechanism. The SLI was established by adding 4% DSS in the drinking water of mice, and the effects of GA (5, 20 mg/kg, p.o., once a day for 7 days) in hepatic tissues were analyzed. HepG2 cells were induced by lipopolysaccharide (LPS) to detect the effect of GA on ferroptosis and the underlying mechanism. Pathological damage was determined by H&E. Liver parameters (AST and ALT), antioxidant enzyme activities (MDA and SOD), and the level of Fe²⁺ in the liver were detected by kits. Cytokine levels (TNF-α, IL-1β, and IL-6) and Gpx4 activity in the liver were detected by ELISA. Finally, the activation of nuclear factor erythroid 2-like 2 (Nrf2) was detected to explore the mechanism. The results indicated that GA significantly attenuated DSS-induced hepatic pathological damage, liver parameters, and cytokine levels and increased the antioxidant enzyme activities. Moreover, GA attenuated ferroptosis in DSS-induced liver injury and upregulated Gpx4 expression in DSS-induced mice. Mechanistic experiments revealed that GA activated Nrf2 in mice. Taken together, this study demonstrates that GA can alleviate ferroptosis in SLI in DSS-induced colitis mice, and its protective effects are associated with activating the Nrf2-Gpx4 signaling pathway.

Diphenyl Diselenide Alleviates Tert-Butyl Hydrogen Peroxide-Induced Oxidative Stress and Lipopolysaccharide-Induced Inflammation in Rat Glomerular Mesangial Cells

Hyperglycemia, oxidative stress, and inflammation play key roles in the onset and development of diabetic complications such as diabetic nephropathy (DN). Diphenyl diselenide (DPDS) is a stable and simple organic selenium compound with anti-hyperglycemic, anti-inflammatory, and anti-oxidative activities. Nevertheless, in vitro, the role and molecular mechanism of DPDS on DN remains unknown. Therefore, we investigated the effects of DPDS on tert-butyl hydrogen peroxide (t-BHP)-induced oxidative stress and lipopolysaccharide (LPS)-induced inflammation in rat glomerular mesangial (HBZY-1) cells and explored the underlying mechanisms. DPDS attenuated t-BHP-induced cytotoxicity, concurrent with decreased intracellular ROS and MDA contents and increased SOD activity and GSH content. Moreover, DPDS augmented the protein and mRNA expression of Nrf2, HO-1, NQO1, and GCLC in t-BHP-stimulated HBZY-1 cells. In addition, DPDS suppressed LPS-induced elevations of intracellular content and mRNA expression of interleukin (IL)-6, IL-1β and TNF-α. Furthermore, LPS-induced NFκB activation and high phosphorylation of JNK and ERK1/2 were markedly suppressed by DPDS in HBZY-1 cells. In summary, these data demonstrated that DPDS improves t-BHP-induced oxidative stress by activating the Nrf2/Keap1 pathway, and also improves LPS-induced inflammation via inhibition of the NFκB/MAPK pathways in HBZY-1 cells, suggesting that DPDS has the potential to be developed as a candidate for the prevention and treatment of DN.

Ambroxol, a mucolytic agent, boosts HO-1, suppresses NF-κB, and decreases the susceptibility of the inflamed rat colon to apoptosis: A new treatment option for treating ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology that increases the risk of developing colorectal cancer and imposes a lifelong healthcare burden on millions of patients worldwide. Current treatment strategies are associated with significant risks and have been shown to be fairly effective. Hence, discovering new therapies that have better efficacy and safety profiles than currently exploited therapeutic strategies is challenging. It has been well delineated that NF-κB/Nrf2 crosstalk is a chief player in the interplay between oxidative stress and inflammation. Ambroxol hydrochloride, a mucolytic agent, has shown antioxidant and anti-inflammatory activity in humans and animals and has not yet been examined for the management of UC. Therefore, our approach was to investigate whether ambroxol could be effective to combat UC using the common acetic acid rat model. Interestingly, a high dose of oral ambroxol (200 mg/kg/day) reasonably improved the microscopic and macroscopic features of the injured colon. This was linked to low disease activity and a reduction in the colonic weight/length ratio. In the context of that, ambroxol boosted Nrf2 activity and upregulated HO-1 and catalase to augment the antioxidant defense against oxidative damage. Besides, ambroxol inactivated NF-κB signaling and its consequent target pro-inflammatory mediators, IL-6 and TNF-α. In contrast, IL-10 is upregulated. Consistent with these results, myeloperoxidase activity is suppressed. Moreover, ambroxol decreased the susceptibility of the injured colon to apoptosis. To conclude, our findings highlight the potential application of ambroxol to modify the progression of UC by its anti-inflammatory, antioxidant, and antiapoptotic properties.

Inflammatory auto-immune diseases of the intestine and their management by natural bioactive compounds

Autoimmune diseases are caused by the overactivity of the immune system towards self-constituents. Risk factors of autoimmune diseases are multiple and include genetic, epigenetic, environmental, and psychological. Autoimmune chronic inflammatory bowel diseases, including celiac and inflammatory diseases (Crohn's disease and ulcerative colitis), constitute a significant health problem worldwide. Besides the complexity of the symptoms of these diseases, their treatments have only been palliative. Numerous investigations showed that natural phytochemicals could be promising strategies to fight against these autoimmune diseases. In this respect, plant-derived natural compounds such as flavonoids, phenolic acids, and terpenoids exhibited significant effects against three autoimmune diseases affecting the intestine, particularly bowel diseases. This review focuses on the role of natural compounds obtained from medicinal plants in modulating inflammatory auto-immune diseases of the intestine. It covers the most recent literature related to the effect of these natural compounds in the treatment and prevention of auto-immune diseases of the intestine.

Inhibiting Ferroptosis: A Novel Approach for Ulcerative Colitis Therapeutics

Ulcerative colitis (UC) is a recurrent and persistent nonspecific inflammatory bowel disease (IBD) that greatly affects human survival and social wealth. Despite the advances in the treatment of UC, there is still a high demand for novel therapeutic strategies for UC patients. Cell death is critical to the development and progression of UC. Understanding how intestinal cells die and how to prevent damage to intestinal cells is of great interest for the diagnosis and early treatment of UC. Ferroptosis, a novel form of regulated cell death (RCD) manifested by iron accumulation, lipid peroxidation, and excessive reactive oxygen species (ROS) production, has been shown to contribute to the development and progression of UC. Inhibitors of ferroptosis have been validated in models of UC. Here, we reviewed the mechanisms of initiation and control of ferroptosis and summarize the therapeutic activity of ferroptosis inhibitors in models of UC. We further discussed the possibility of inhibiting ferroptosis as a novel therapeutic target for UC. These findings revealed novel mechanisms to protect the colonic mucosa and highlighted the importance of ferroptosis in the disease process.

Dapagliflozin attenuates cholesterol overloading-induced injury in mice hepatocytes with type 2 diabetes mellitus (T2DM) via eliminating oxidative damages

Cholesterol overloading-induced damages on hepatocytes cause liver dysfunctions, which further damages cholesterol metabolism and results in visceral fat accumulation in patients with type 2 diabetes mellitus (T2DM). The sodium-glucose cotransporter 2 (SGLT2) inhibitor Dapagliflozin has been reported to regulate cholesterol levels in T2DM patients, but the underlying mechanisms have not been studied. In the present study, we initially established in vivo T2DM mice models, and our results showed that both free cholesterol (FC) and cholesteryl ester (CE) were accumulated, while the pro-proliferation associated genes were downregulated in T2DM mice liver tissues, which were reversed by Dapagliflozin co-treatment. Similarly, the mice primary hepatocytes were loaded with cholesterol to establish in vitro models, and we expectedly found that Dapagliflozin attenuated cholesterol-overloading induced cytotoxicity and cellular senescence in the hepatocytes. Then, we noticed that oxidative damages occurred in T2DM mice liver tissues and cholesterol treated hepatocytes, which could be suppressed by Dapagliflozin. Also, elimination of Reactive Oxygen Species (ROS) by N-acetyl-L-cysteine (NAC) recovered cellular functions of hepatocytes in vitro and in vivo. Furthermore, the potential underlying mechanisms were uncovered, and our data suggested that Dapagliflozin activated the anti-oxidant Nrf2/HO-1 pathway in mice hepatocytes, and silencing of Nrf2 abrogated the protective effects of Dapagliflozin on cholesterol-overloaded hepatocytes. Collectively, we concluded that Dapagliflozin recovered cholesterol metabolism functions in T2DM mice liver via activating the anti-oxidant Nrf2/HO-1 pathway, and our data supported that Dapagliflozin was a potential therapeutic drug to eliminate cholesterol-induced cytotoxicity during T2DM pathogenesis.

The Attenuation of Chronic Ulcerative Colitis by (R)-salbutamol in Repeated DSS-Induced Mice

Racemic salbutamol ((RS)-sal), which consist of the same amount of (R)-sal and (S)-sal, has been used for asthma and COPD due to its bronchodilation effect. However, the effect of (R)-sal on repeated dextran sulfate sodium (DSS)-induced chronic colitis has not yet been investigated. In this study evaluated the potential effect of (R)-, (S)-, and (RS)-sal in mice with repeated DSS-induced chronic colitis and investigated the underlying mechanisms. Here, we verified that chronic colitis was significantly attenuated by (R)-sal, which was evidenced by notably mitigated body weight loss, disease activity index (DAI), splenomegaly, colonic lengths shortening, and histopathological scores. (R)-sal treatment noticeably diminished the levels of inflammatory cytokines (such as TNF-α, IL-6, IL-1β, and IFN-γ). Notably, the efficacy of (R)-sal was better than that of (RS)-sal. Further research revealed that (R)-sal mitigated colonic CD4 leukocyte infiltration, decreased NF-κB signaling pathway activation, improved the Nrf-2/HO-1 signaling pathway, and increased the expression of ZO-1 and occludin. In addition, (R)-sal suppressed the levels of TGF-β1, α-SMA, and collagen in mice with chronic colitis. Furthermore, the 16S rDNA sequences analyzed of the intestinal microbiome revealed that (R)-sal could mitigate the intestinal microbiome structure and made it more similar to the control group, which mainly by relieving the relative abundance of pathogens (such as Bacteroides) and increasing the relative abundance of probiotics (such as Akkermansia). Therefore, (R)-sal ameliorates repeated DSS-induced chronic colitis in mice by improving inflammation, suppressing oxidative stress, mitigating intestinal barrier function, relieving intestinal fibrosis, and regulating the intestinal microbiome community. These results indicate that (R)-sal maybe a novel treatment alternative for chronic colitis.

Gut Microbiome and Organ Fibrosis

Fibrosis is a pathological process associated with most chronic inflammatory diseases. It is defined by an excessive deposition of extracellular matrix proteins and can affect nearly every tissue and organ system in the body. Fibroproliferative diseases, such as intestinal fibrosis, liver cirrhosis, progressive kidney disease and cardiovascular disease, often lead to severe organ damage and are a leading cause of morbidity and mortality worldwide, for which there are currently no effective therapies available. In the past decade, a growing body of evidence has highlighted the gut microbiome as a major player in the regulation of the innate and adaptive immune system, with severe implications in the pathogenesis of multiple immune-mediated disorders. Gut microbiota dysbiosis has been associated with the development and progression of fibrotic processes in various organs and is predicted to be a potential therapeutic target for fibrosis management. In this review we summarize the state of the art concerning the crosstalk between intestinal microbiota and organ fibrosis, address the relevance of diet in different fibrotic diseases and discuss gut microbiome-targeted therapeutic approaches that are current being explored.

Furin inhibits epithelial cell injury and alleviates experimental colitis by activating the Nrf2-Gpx4 signaling pathway

BACKGROUND AND AIM

Furin is a proprotein convertase reported to have protective effects in several autoimmune diseases. However, the role of furin in ulcerative colitis (UC) remains unclear. We aimed to clarify this role.

METHODS

Furin expression was measured in UC and dextran sulfate sodium (DSS)-induced colitis. Gain- and loss-of-function experiments were conducted to evaluate the effect of furin in UC using DSS-treated NCM460 cells. Several ferroptotic parameters, including cell viability, cell death rate, lipid reactive oxygen species level, mitochondrial membrane damage and glutathione peroxidase 4 (Gpx4) expression, were measured. Exogenous furin was used to treat the DSS-induced colitis in mice to confirm the results in vivo. Finally, the activation of nuclear factor erythroid 2-like 2 (Nrf2) was detected to explore the mechanism.

RESULTS

Furin expression was aberrant in UC. Furin overexpression attenuated DSS-induced ferroptosis-like injury and upregulated Gpx4 in NCM460 cells, whereas silencing furin had the opposite effects. Exogenous furin treatment alleviated DSS-induced colitis in mice by upregulating Gpx4. Mechanistic experiments revealed that furin activated Nrf2 both in vitro and in vivo.

CONCLUSIONS

Furin protects epithelial cells from DSS-induced ferroptosis-like cell injury and alleviates experimental colitis by activating the Nrf2-Gpx4 signaling pathway.

Role of inflammation and oxidative stress in tissue damage associated with cystic fibrosis: CAPE as a future therapeutic strategy

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, responsible for the synthesis of the CFTR protein, a chloride channel. The gene has approximately 2000 known mutations and all of them affect in some degree the protein function, which makes the pathophysiological manifestations to be multisystemic, mainly affecting the respiratory, gastrointestinal, endocrine, and reproductive tracts. Currently, the treatment of the disease is restricted to controlling symptoms and, more recently, a group of drugs that act directly on the defective protein, known as CFTR modulators, was developed. However, their high cost and difficult access mean that their use is still very restricted. It is important to search for safe and low-cost alternative therapies for CF and, in this context, natural compounds and, mainly, caffeic acid phenethyl ester (CAPE) appear as promising strategies to assist in the treatment of the disease. CAPE is a compound derived from propolis extracts that has antioxidant and anti-inflammatory activities, covering important aspects of the pathophysiology of CF, which points to the possible benefit of its use in the disease treatment. To date, no studies have effectively tested CAPE for CF and, therefore, we intend with this review to elucidate the role of inflammation and oxidative stress for tissue damage seen in CF, associating them with CAPE actions and its pharmacologically active derivatives. In this way, we offer a theoretical basis for conducting preclinical and clinical studies relating the use of this molecule to CF.

Dehydrocorydaline Protects Against Sepsis-Induced Myocardial Injury Through Modulating the TRAF6/NF-κB Pathway

We aim to investigate the effect and mechanism of dehydrocorydaline (Deh), an alkaloidal component isolated from Rhizoma corydalis, in the treatment of sepsis-mediated myocardial injury. Lipopolysaccharide (LPS) was taken to construct an in-vitro sepsis-myocardial injury models H9C2 cardiomyocytes. The in-vivo model of sepsis in C57BL/6 mice was induced by intraperitoneal injection of Escherichia coli (E. coli). The in-vitro and in-vivo models were treated with Deh in different concentrations, respectively. Hematoxylin-eosin (HE) staining, Masson staining, and immunohistochemistry (IHC) staining were taken to evaluate the histopathological changes of the heart. ELISA was applied to evaluate the levels of inflammatory factors, including IL-6, IL-1β, TNFα, IFNγ, and oxidized factors SOD, GSH-PX in the plasma or culture medium. Western blot was used to measure the expressions of Bax, Bcl2, Caspase3, iNOS, Nrf2, HO-1, TRAF6, NF-κB in heart tissues and cells. The viability of H9C2 cardiomyocytes was detected by the CCK8 method and BrdU assay. The ROS level in the H9C2 cardiomyocytes were determined using immunofluorescence. As a result, Deh treatment improved the survival of sepsis mice, reduced TUNEL-labeled apoptosis of cardiomyocytes. In vitro, Deh enhanced the viability of LPS-induced H9C2 cardiomyocytes and inhibited cell apoptosis. Additionally, Deh showed significant anti-inflammatory and anti-oxidative stress functions via decreasing IL-1β, IL-6, TNFα, and IFNγ levels, mitigating ROS level, up-regulating Nrf2/HO-1, SOD, and GSH-PX expressions dose-dependently. Mechanistically, Deh inhibited TRAF6 expression and the phosphorylation of NF-κB p65. The intervention with a specific inhibitor of TRAF6 (C25-140) or NF-κB inhibitor (BAY 11-7082) markedly repressed the protective effects mediated by Deh. In conclusion, Deh restrains sepsis-induced cardiomyocyte injury by inhibiting the TRAF6/NF-κB pathway.

Natural-Derived Polysaccharides From Plants, Mushrooms, and Seaweeds for the Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease impairing the gastrointestinal tract, and its incidence and prevalence have been increasing over time worldwide. IBD greatly reduces peoples' quality of life and results in several life-threatening complications, including polyp, toxic colonic dilatation, intestinal perforation, gastrointestinal bleeding, and cancerization. The current therapies for IBD mainly include drugs for noncritical patients and operation for critical patients. However, continuous use of these drugs causes serious side effects and increased drug resistance, and the demand of effective and affordable drugs with minimal side effects for IBD sufferers is urgent. Natural-derived polysaccharides are becoming a research hotspot for their therapeutic effects on IBD. This study focuses on the research progress of various natural polysaccharides from plants, seaweeds, and mushrooms for the treatment of IBD during recent 20 years. Regulation of oxidative stress, inflammatory status, gut microbiota, and immune system and protection of the intestinal epithelial barrier function are the underlying mechanisms for the natural-derived polysaccharides to treat IBD. The excellent efficacy and safety of polysaccharides make them promising candidates for IBD therapy.

Blockade of TLRs-triggered macrophage activation by caffeic acid exerted protective effects on experimental ulcerative colitis

Ulcerative colitis (UC) represents a relapsing and inflammatory bowel disease which is commonly linked with the communications between dysfunction of epithelium and mucosal immune responses. Though caffeic acid (CA) has numerous pharmacological capacities, whether CA demonstrates immunoregulation on the mucosal immune responses remains ill-defined. Herein, the present research demonstrated that CA could dramatically attenuate the mucosal inflammation, as evidenced by improving the disease severity, serum biochemical indexes, mucosal ulcerations, loss of epithelium and crypts, and secretion of inflammatory cytokines in the colonic homogenates and explants culture. Consistently, CA could interfere with the infiltration and function of mononuclear macrophages in the mucosa, MLNs, and spleens of UC. Furthermore, CA exerted direct suppressive effects on the activation of BMDMs upon the exposure of TLRs agonists in vitro. Taken together, CA could attenuate DSS-induced murine UC through interfering with the activation of macrophages, which might provide an alternative therapeutic option for UC.

PDE9 Inhibitor PF-04447943 Attenuates DSS-Induced Colitis by Suppressing Oxidative Stress, Inflammation, and Regulating T-Cell Polarization

Ulcerative colitis (UC) is a form of inflammatory bowel disease, which manifests as irritation or swelling and sores in the large intestine in a relapsing and remitting manner. In a dextran sulfate sodium sulfate (DSS)-induced UC model in female mice, we found that the levels of cyclic guanosine monophosphate (cGMP) are reduced, while the expression of phosphodiesterase 9A (PDE9A) is highest among all phosphodiesterase (PDEs). Since PDE9 has the highest affinity toward cGMP, we evaluated the selective PDE9 inhibitor PF-04447943 (PF) as a potential candidate for UC treatment. PF has been extensively studies in cognitive function and in sickle cell disease, but not in models for inflammatory bowel disease (IBD). Therefore, we used female C57BL/6 mice treated with 3% DSS alone or co-treated with PF or sulfasalazine (SASP) to study the body weight, colon length, histopathology, and measure superoxide dismutase (SOD), malondialdehyde (MDA), and cGMP level, as well as cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), interleukin-12/23 (IL-12/23), interleukin-10 (IL-10), and pathways including nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), and inflammasome activation. In addition, the number of dendritic cells (DC) and regulatory T cells (Treg cell) was assessed in the spleen, lymph node, and colon using flow cytometry. DSS reduced the number of goblet cells, decreased colon lengths and body weights, all of them were attenuated by PF treatment. It also suppressed the elevated level of inflammatory cytokines and increased level the anti-inflammatory cytokine, IL-10. PF treatment also reduced the DSS-induced inflammation by suppressing oxidative stress, NF-κB, STAT3, and inflammasome activation, by upregulating nuclear factor erythroid 2-related factor 2 (Nrf-2) and its downstream proteins via extracellular signal-regulated kinase (ERK) phosphorylation. Importantly, PF reversed imbalance in Treg/T helper 17 cells (Th17) cells ratio, possibly by regulating dendritic cells and Treg developmental process. In summary, this study shows the protective effect of a PDE9A inhibitor in ulcerative colitis by suppressing oxidative stress and inflammation as well as reversing the Treg/Th17 cells imbalance.

Heme Oxygenase-1 in Gastrointestinal Tract Health and Disease

Heme oxygenase 1 (HO-1) is the rate-limiting enzyme of heme oxidative degradation, generating carbon monoxide (CO), free iron, and biliverdin. HO-1, a stress inducible enzyme, is considered as an anti-oxidative and cytoprotective agent. As many studies suggest, HO-1 is highly expressed in the gastrointestinal tract where it is involved in the response to inflammatory processes, which may lead to several diseases such as pancreatitis, diabetes, fatty liver disease, inflammatory bowel disease, and cancer. In this review, we highlight the pivotal role of HO-1 and its downstream effectors in the development of disorders and their beneficial effects on the maintenance of the gastrointestinal tract health. We also examine clinical trials involving the therapeutic targets derived from HO-1 system for the most common diseases of the digestive system.

The Nrf2 in the pathophysiology of the intestine: Molecular mechanisms and therapeutic implications for inflammatory bowel diseases

Nrf2 (nuclear factor erythroid 2-related factor 2) is a stress-responsive transcription factor, associated with cellular homeostasis. Under normal conditions Nrf2 is kept in the cytoplasm by Kelch-like ECH-associated protein 1 (Keap1) which facilitates its degradation. Meanwhile, oxidative or electrophilic stress trigger Keap1 dissociation from the Nrf2/Keap1 complex and Nrf2 translocation to the nucleus where it induces the expression of numerous anti-oxidative and anti-inflammatory genes. The Nrf2/Keap1 axis plays a crucial role in the development of gastrointestinal (GI) tract and the maintenance of its proper functionality. This axis also seems to be a promising candidate for prevention of inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), as well as their severe complications such as intestinal fibrosis and colorectal cancer. This review focuses on the role of Nrf2/Keap1 in 1) the development and proper functionality of GI tract, 2) the pathophysiology of GI diseases and their long-term complications, 3) the effectiveness of currently used drugs and non-conventional treatments which influence Nrf2/Keap1 and are potentially effective in IBD treatment, as well as 4) the effect of gut microbiota on Nrf2/Keap1 pathway in IBD.