Sulphur dioxide ameliorates colitis related pathophysiology and inflammation

Dynamics and metabolic effects of intestinal gases in healthy humans

Many living beings use exogenous and/or endogenous gases to attain evolutionary benefits. We make a comprehensive assessment of one of the major gaseous reservoirs in the human body, i.e., the bowel, providing extensive data that may serve as reference for future studies. We assess the intestinal gases in healthy humans, including their volume, composition, source and local distribution in proximal as well as distal gut. We analyse each one of the most abundant intestinal gases including nitrogen, oxygen, nitric oxide, carbon dioxide, methane, hydrogen, hydrogen sulfide, sulfur dioxide and cyanide. For every gas, we describe diffusive patterns, active trans-barrier transport dynamics, chemical properties, intra-/extra-intestinal metabolic effects mediated by intracellular, extracellular, paracrine and distant actions. Further, we highlight the local and systemic roles of gasotransmitters, i.e., signalling gaseous molecules that can freely diffuse through the intestinal cellular membranes. Yet, we provide testable hypotheses concerning the still unknown effects of some intestinal gases on the myenteric and submucosal neurons.

Multifaceted antineoplastic curative potency of novel water-soluble methylimidazole-based oxidovanadium (IV) complex against triple negative mammary carcinoma

A bunch of complexes harboring vanadium as metal centers have been reported to exhibit a wide array of antineoplastic properties that come under non‑platinum metallodrug series and emerge to offer alternative therapeutic strategies from the mechanistic behaviors of platinum-drugs. Though antineoplastic activities of vanado-complexes have been documented against several animal and xenografted human cancers, the definite mechanism of action is yet to unveil. In present study, a novel water soluble 1-methylimidazole substituted mononuclear dipicolinic acid based oxidovanadium (IV) complex (OVMI) has been evaluated for its antineoplastic properties in breast carcinoma both in vitro and in vivo. OVMI has been reported to generate cytotoxicity in human triple negative breast carcinoma cells, MDA-MB-231 as well as in mouse 4T1 cells by priming them for apoptosis. ROS-mediated, mitochondria-dependent as well as ER-stress-evoked apoptotic death seemed to be main operational hub guiding the cytotoxicity of OVMI in vitro. Moreover, OVMI has been noticed to elicit antimetastatic effect in vitro. Therapeutic application of OVMI has been extended on 4T1-based mammary tumor of female Balb/c mice, where it has been found to reduce tumor size, volume and restore general tissue architecture successfully to a great extent. Apart from that, OVMI has been documented to limit 4T1-based secondary pulmonary metastasis along with being non-toxic and biocompatible in vivo.

Recent advances in sulfur dioxide releasing nanoplatforms for cancer therapy

Sulfur dioxide (SO2), long considered to be a harmful atmospheric pollutant, has recently been posited as the fourth gasotransmitter, as it is produced endogenously in mammals and has important pathophysiological effects. The field of tumor therapy has witnessed a paradigm shift with the emergence of SO2-based gas therapy. This has been possible because SO2 is a potent glutathione consumer that can promote the production of reactive oxygen species, eventually leading to oxidative-stress-induced cancer cell death. Nevertheless, this therapeutic gas cannot be directly administrated in gaseous form. Thus, various nano formulations incorporating SO2 donors or prodrugs capable of storing and releasing SO2 have been developed in an attempt to achieve active/passive intratumoral accumulation and SO2 release in the tumor microenvironment. In this review article, the advances over the past decade in nanoplatforms incorporating sulfur SO2 prodrugs to provide controlled release of SO2 for cancer therapy are summarized. We first describe the synthesis of polypeptide SO2 prodrugs to overcome multiple drug resistance that was pioneered by our group, followed by other macromolecular SO2 prodrug structures that self-assemble into nanoparticles for tumor therapy. Second, we describe nanoplatforms composed of various small-molecule SO2 donors with endogenous or exogenous stimuli responsiveness, including thiol activated, acid-sensitive, and ultraviolet or near-infrared light-responsive SO2 donors, which have been used for tumor inhibition. Combinations of SO2 gas therapy with photodynamic therapy, chemotherapy, photothermal therapy, sonodynamic therapy, and nanocatalytic tumor therapy are also presented. Finally, we discuss the current limitations and challenges and the future outlook for SO2-based gas therapy. STATEMENT OF SIGNIFICANCE: Gas therapy is attracting increasing attention in the scientific community because it is a highly promising strategy against cancer owing to its inherent biosafety and avoidance of drug resistance. Sulfur dioxide (SO2) is recently found to be produced endogenously in mammals with important pathophysiological effects. This review summarizes recent advances in SO2 releasing nanosystems for cancer therapy, including polymeric prodrugs, endogenous or exogenous stimulus-activated SO2 donors delivered by nanoplatform and combination therapy strategies.

Steamed broccoli sprouts alleviate DSS-induced inflammation and retain gut microbial biogeography in mice

IMPORTANCE

Evaluating bacterial communities across different locations in the gut provides a greater insight than fecal samples alone and provides an additional metric by which to evaluate beneficial host-microbe interactions. Here, we show that 10% steamed broccoli sprouts in the diet protects mice from the negative effects of dextran sodium sulfate-induced colitis, that colitis erases biogeographic patterns of bacterial communities in the gut, and that the cecum is not likely to be a significant contributor to colonic bacteria of interest in the DSS mouse model of ulcerative colitis. Mice fed the broccoli sprout diet during colitis performed better than mice fed the control diet while receiving DSS. The identification of accessible dietary components and concentrations that help maintain and correct the gut microbiome may provide universal and equitable approaches to IBD prevention and recovery, and broccoli sprouts represent a promising strategy.

Steamed broccoli sprouts alleviate DSS-induced inflammation and retain gut microbial biogeography in mice

Inflammatory Bowel Diseases (IBD) are devastating conditions of the gastrointestinal tract with limited treatments, and dietary intervention may be effective, and affordable, for managing symptoms. Glucosinolate compounds are highly concentrated in broccoli sprouts, especially glucoraphanin, and can be metabolized by certain mammalian gut bacteria into anti inflammatory isothiocyanates, such as sulforaphane. Gut microbiota exhibit biogeographic patterns, but it is unknown if colitis alters these or whether the location of glucoraphanin metabolizing bacteria affects anti-inflammatory benefits. We fed specific pathogen free C57BL/6 mice either a control diet or a 10% steamed broccoli sprout diet, and gave a three-cycle regimen of 2.5% dextran sodium sulfate (DSS) in drinking water over a 34-day experiment to simulate chronic, relapsing ulcerative colitis. We monitored body weight, fecal characteristics, lipocalin, serum cytokines, and bacterial communities from the luminal and mucosa-associated populations in the jejunum, cecum, and colon. Mice fed the broccoli sprout diet with DSS treatment performed better than mice fed the control diet with DSS, including significantly more weight gain, lower Disease Activity Indexes, lower plasma lipocalin and proinflammatory cytokines, and higher bacterial richness in all gut locations. Bacterial communities were assorted by gut location, but were more homogenous across locations in the control diet + DSS mice. Importantly, our results showed that broccoli sprout feeding abrogated the effects of DSS on gut microbiota, as bacterial richness and biogeography were similar between mice receiving broccoli sprouts with and without DSS. Collectively, these results support the protective effect of steamed broccoli sprouts against dysbiosis and colitis induced by DSS.

Importance

Evaluating bacterial communities across different locations in the gut provides a greater insight than fecal samples alone, and provides an additional metric by which to evaluate beneficial host-microbe interactions. Here, we show that 10% steamed broccoli sprouts in the diet protects mice from the negative effects of dextran sodium sulfate induced colitis, that colitis erases biogeographical patterns of bacterial communities in the gut, and that the cecum is not likely to be a significant contributor to colonic bacteria of interest in the DSS mouse model of ulcerative colitis. Mice fed the broccoli sprout diet during colitis performed better than mice fed the control diet while receiving DSS. The identification of accessible dietary components and concentrations that help maintain and correct the gut microbiome may provide universal and equitable approaches to IBD prevention and recovery, and broccoli sprouts represent a promising strategy.

Sulfur content in foods and beverages and its role in human and animal metabolism: A scoping review of recent studies

Sulfur is a vital element that all living things require, being a component of proteins and other bio-organic substances. The various kinds and varieties of microbes in nature allow for the transformation of this element. It also should be emphasized that volatile sulfur compounds are typically present in food in trace amounts. Life cannot exist without sulfur, yet it also poses a potential health risk. The colon's sulfur metabolism, which is managed by eukaryotic cells, is much better understood than the S metabolism in gastrointestinal bacteria. Numerous additional microbial processes are anticipated to have an impact on the content and availability of sulfated compounds, as well as intestinal S metabolism. Hydrogen sulfide is the sulfur derivative that has attracted the most attention in relation to colonic health, but it is still unclear whether it is beneficial or harmful. Several lines of evidence suggest that sulfate-reducing bacteria or exogenous hydrogen sulfide may be the root cause of intestinal ailments, including inflammatory bowel diseases and colon cancer. Taurine serves a variety of biological and physiological purposes, including roles in inflammation and protection, additionally, low levels of taurine can be found in bodily fluids, and taurine is the primary sulfur component present in muscle tissue (serum and urine). The aim of this scoping review was to compile data from the most pertinent scientific works about S compounds' existence in food and their metabolic processes. The importance of S compounds in various food products and how these compounds can impact metabolic processes are both stressed in this paper.

Sulfur Dioxide: Endogenous Generation, Biological Effects, Detection, and Therapeutic Potential

Significance: Previously, sulfur dioxide (SO₂) was recognized as an air pollutant. However, it is found to be endogenously produced in mammalian tissues. As a new gasotransmitter, SO₂ is involved in regulating the structure and function of blood vessels, heart, lung, gastrointestinal tract, nervous system, etc.Recent Advances: Increasing evidence showed that endogenous SO₂ regulates cardiovascular physiological processes, such as blood pressure control, vasodilation, maintenance of the normal vascular structure, and cardiac negative inotropy. Under pathological conditions including hypertension, atherosclerosis, vascular calcification, aging endothelial dysfunction, myocardial injury, myocardial hypertrophy, diabetic myocardial fibrosis, sepsis-induced cardiac dysfunction, pulmonary hypertension, acute lung injury, colitis, epilepsy-related brain injury, depression and anxiety, and addictive drug reward memory consolidation, endogenous SO₂ protects against the pathological changes via different molecular mechanisms and the disturbed SO₂/aspartate aminotransferase pathway is likely involved in the mechanisms for the earlier mentioned pathologic processes. Critical Issues: A comprehensive understanding of the biological effects of endogenous SO₂ is extremely important for the development of novel SO₂ therapy. In this review, we summarized the biological effects, mechanism of action, SO₂ detection methods, and its related prodrugs. Future Directions: Further studies should be conducted to understand the effects of endogenous SO₂ in various physiological and pathophysiological processes and clarify its underlying mechanisms. More efficient and accurate SO₂ detection methods, as well as specific and effective SO₂-releasing systems should be designed for the treatment and prevention of clinical related diseases. The translation from SO₂ basic medical research to its clinical application is also worthy of further study. Antioxid. Redox Signal. 36, 256-274.

Regulation of Endoplasmic Reticulum Stress-Autophagy: A Potential Therapeutic Target for Ulcerative Colitis

Ulcerative colitis (UC) is a chronic nonspecific inflammation that mainly affects the mucosa and submucosa of the rectum and colon. Numerous studies have shown that endoplasmic reticulum stress (ERS)-induced autophagy plays a vital role in the pathogenesis of UC. ERS is the imbalance of internal balance caused by misfolded or unfolded proteins accumulated in the endoplasmic reticulum (ER).Excessive ERS triggers the unfolded protein response (UPR), an increase in inositol-requiring enzyme 1, and a Ca²⁺ overload, which activates the autophagy pathway. Autophagy is an evolutionarily conserved method of cellular self-degradation. Dysregulated autophagy causes inflammation, disruption of the intestinal barrier, and imbalance of intestinal homeostasis, therefore increasing the risk of colonic diseases. This review summarizes the pathogenesis of ERS, UPR, and ERS-related autophagy in UC, providing potential new targets and more effective treatment options for UC.

Exogenous SO2 donor treatment impairs reconsolidation of drug reward memory in mice

Substance-related and addictive disorders (SRADs) are characterized by compulsive drug use and recurrent relapse. The persistence of pathological drug-related memories indisputably contributes to a high propensity to relapse. Hence, strategies to disrupt reconsolidation of drug reward memory are currently being pursued as potential anti-relapse interventions. Sulfur dioxide (SO2), acting as a potential gaseous molecule, endogenously derives from sulfur amino acid and can exert significant neural regulatory effects. However, the role of SO2 in reconsolidation of drug memory has not been determined. In the present study, we used morphine- or cocaine-induced conditioned place preference (CPP) mouse models with retrieval to investigate the effects of exogenous SO2 donor treatment on reconsolidation of drug reward memory. We found that administration of SO2 donor immediately after the retrieval impaired the expression of morphine or cocaine CPP. Furthermore, the exogenous SO2 donor treatment 6 h post-retrieval or in the absence of retrieval had no effect on drug reward memory and the expression of CPP. SO2 itself did not produce aversive effects nor did it acutely block morphine CPP. Our results indicate that exogenous SO2 impairs reconsolidation of drug reward memory rather than inhibits the expression of drug reward memory. As such, SO2 holds potential for the treatment and prevention of SRADs and should be studied further.

Inflammasome Regulation: Therapeutic Potential for Inflammatory Bowel Disease

Inflammasomes are multiprotein complexes formed to regulate the maturation of pro-inflammatory caspases, in response to intracellular or extracellular stimulants. Accumulating studies showed that the inflammasomes are implicated in the pathogenesis of inflammatory bowel disease (IBD), although their activation is not a decisive factor for the development of IBD. Inflammasomes and related cytokines play an important role in the maintenance of gut immune homeostasis, while its overactivation might induce excess immune responses and consequently cause tissue damage in the gut. Emerging studies provide evidence that some genetic abnormalities might induce enhanced NLRP3 inflammasome activation and cause colitis. In these cases, the colonic inflammation can be ameliorated by blocking NLRP3 activation or its downstream cytokine IL-1β. A number of natural products were shown to play a role in preventing colon inflammation in various experimental colitis models. On the other hand, lack of inflammasome function also causes intestinal abnormalities. Thus, an appropriate regulation of inflammasomes might be a promising therapeutic strategy for IBD intervention. This review aims at summarizing the main findings in these studies and provide an outline for further studies that might contribute to our understanding of the role of inflammasomes in the pathogenesis and therapeutic treatment of IBD.

The Role of Autophagy in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory disease, including ulcerative colitis (UC) and Crohn’s disease (CD). The abnormality of inflammatory and immune responses in the intestine contributes to the pathogenesis and progression of IBD. Autophagy is a vital catabolic process in cells. Recent studies report that autophagy is highly involved in various kinds of diseases, especially inflammation-related diseases, such as IBD. In this review, the biological characteristics of autophagy and its role in IBD will be described and discussed based on recent literature. In addition, several therapies for IBD through modulating the inflammasome and intestinal microbiota taking advantage of autophagy regulation will be introduced. We aim to bring new insight in the exploration of mechanisms for IBD and development of novel therapeutic strategies against IBD.

Protective Effect of Methane-Rich Saline on Acetic Acid-Induced Ulcerative Colitis via Blocking the TLR4/NF-κB/MAPK Pathway and Promoting IL-10/JAK1/STAT3-Mediated Anti-inflammatory Response

Ulcerative colitis (UC) is an inflammation-related disease involved in uncontrolled inflammation and oxidative stress and is characterized by high recurrence and relapse risk. As a rising star in gas medicine, methane owns the properties of anti-inflammation, antioxidation, and antiapoptosis. Based on the possible mechanism, we aimed to investigate the effect of methane on UC. Methane-rich saline (MRS) was introduced here, and UC was induced by acetic acid. All the C57BL/6 mice were allocated into groups as follows: control group, colitis model group, colitis treated with salazosulfapyridine (SASP) group, and colitis treated with MRS (1 or 10 ml/kg) groups. Tissue damage, the degree of inflammation, oxidative stress, and apoptosis were evaluated in the study, as well as the TLR4/NF-κB/MAPK and IL-10/JAK1/STAT3 signaling pathways for further exploration of the potential mechanism. The results showed that MRS (1) alleviated tissue damage caused by acetic acid, (2) controlled acetic acid-induced inflammation, (3) inhibited acetic acid-caused oxidative stress, (4) reduced colonic cell apoptosis due to acetic acid, (5) suppressed the TLR-4/NF-κB/MAPK signaling pathway, and (6) activated IL-10/JAK1/STAT3 anti-inflammatory response to improve the injury induced by acetic acid. We conclude that MRS has a protective effect on acetic acid-induced ulcerative colitis in mice via blocking the TLR4/NF-κB/MAPK signaling pathway and promoting the IL-10/JAK1/STAT3-mediated anti-inflammatory response.