Sulfur-Element containing metabolic pathways in human health and crosstalk with the microbiome

Reduced Sulfur Diet Reshapes the Microbiome and Metabolome in Mild-Moderate Ulcerative Colitis

This pilot study investigated the effects of a reduced sulfur (RS) diet on the gut microbiome composition and fecal metabolome in individuals with remitted or active ulcerative colitis (UC). Thirteen participants maintained their habitual diet (control), while nine followed an RS diet for eight weeks (Wk8). Stool and plasma samples were collected at the baseline and Wk8. The sulfur intake decreased in the RS group (-28 g/1000 kcal) versus the control group (-1.7 g/1000 kcal; p < 0.001). The RS group exhibited a significant decrease in lipopolysaccharide-binding protein (-5280 ng/mL), while these levels increased in the control group (620 ng/mL; p < 0.05). The microbiome analysis showed an increased alpha diversity at Wk8 (p < 0.01), suggesting a microbial shift with a RS intake. The metabolic alterations indicated enhanced nitrogen disposal (increased uric acid, methyluric acid, N-acetyl-L-glutamate) and a higher energy demand (elevated ubiquinol and glucose-pyruvate). The RS diet increased beneficial microbes Collinsella stercoris, Asaccharobacter celatus, and Alistipes finegoldii, while decreasing pathobionts Eggerthella lenta and Romboutsia ilealis. Methyluric acid correlated positively with C. stercoris (β = 0.70) and negatively with E. lenta (β = -0.77) suggesting these microbes utilized this metabolite and influenced the microbiome composition. In conclusion, a RS diet promoted microbial diversity, metabolic adaptations, and reduced inflammation, highlighting its potential as a novel strategy for UC management.

Specific Bacterial Taxa and Their Metabolite, DHPS, May Be Linked to Gut Dyshomeostasis in Patients with Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis

Background: Neurodegenerative diseases (NDDs) are multifactorial disorders frequently associated with gut dysbiosis, oxidative stress, and inflammation; however, the pathophysiological mechanisms remain poorly understood. Methods: Using untargeted mass spectrometry-based metabolomics and 16S sequencing of human stool, we investigated bacterial and metabolic dyshomeostasis in the gut microbiome associated with early disease stages across three NDDs-amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD)-and healthy controls (HC). Results: We discovered a previously unrecognized link between a microbial-derived metabolite with an unknown role in human physiology, 2,3-dihydroxypropane-1-sulfonate (DHPS), and gut dysbiosis in NDDs. DHPS was downregulated in AD, ALS, and PD, while bacteria involved in DHPS metabolism, Eubacterium and Desulfovibrio, were increased in all disease cohorts. Additionally, select taxa within the Clostridia class had strong negative correlations to DHPS, suggesting a potential role in DHPS metabolism. A catabolic product of DHPS is hydrogen sulfide, and when in excess, it is known to promote inflammation, oxidative stress, mitochondrial damage, and gut dysbiosis, known hallmarks of NDDs. Conclusions: These findings suggest that cryptic sulfur metabolism via DHPS is a potential missing link in our current understanding of gut dysbiosis associated with NDD onset and progression. As this was a hypothesis generating study, more work is needed to elucidate the role of DHPS in gut dysbiosis and neurodegenerative diseases.

Supersulfide donors and their therapeutic targets in inflammatory diseases

Inflammation is one defense mechanism of the body that has multiple origins, ranging from physical agents to infectious agents including viruses and bacteria. The resolution of inflammation has emerged as a critical endogenous process that protects host tissues from prolonged or excessive inflammation, which can become chronic. Failure of the inflammation resolution is a key pathological mechanism that drives the progression of numerous inflammatory diseases. Owing to the various side effects of currently available drugs to control inflammation, novel therapeutic agents that can prevent or suppress inflammation are needed. Supersulfides are highly reactive and biologically potent molecules that function as antioxidants, redox regulators, and modulators of cell signaling. The catenation state of individual sulfur atoms endows supersulfides with unique biological activities. Great strides have recently been made in achieving a molecular understanding of these sulfur species, which participate in various physiological and pathological pathways. This review mainly focuses on the anti-inflammatory effects of supersulfides. The review starts with an overview of supersulfide biology and highlights the roles of supersulfides in both immune and inflammatory responses. The various donors used to generate supersulfides are assessed as research tools and potential therapeutic agents. Deeper understanding of the molecular and cellular bases of supersulfide-driven biology can help guide the development of innovative therapeutic strategies to prevent and treat diseases associated with various immune and inflammatory responses.

Quantitative study on reducing arsenic concentration in rice by sulfur fertilizer based on meta-analysis

Arsenic (As), a toxic metalloid, is absorbed by rice and subsequently enters the human body through the food chain. Sulfur (S) possesses the capacity to reduce As accumulation in rice tissues and has been widely researched for its contributions to enhancing soil quality. However, a clear quantitative consensus regarding the impact of S application on As bioaccumulation and bioavailability has yet to be established. To gain a more nuanced understanding of the interaction between S and As, a comprehensive analysis was conducted on 318 data sets extracted from 23 articles. Both meta-regression and subgroup analyses were employed to investigate the effect of diverse variables on As accumulation in rice. The results indicated that S had a significant dose-dependent effect on reducing As accumulation in rice. The exogenous S significantly reduced the As concentration in rice by 8.95% and the optimal S/As ratio for inhibiting As accumulation was 1-20. Apart from sulfate S, the incorporation of elemental S, persulfate, thiosulfate, and gypsum has been demonstrated to significantly reduce As accumulation in rice. The exogenous S resulted in a significant reduction in TFroot to shoot content in rice, indicating that S application may impede the physiological process of As transfer from soil to the shoot of rice. Consequently, the exogenous S can effectively mitigate the As accumulation in rice, thereby offering a novel approach to reduce the As content in rice and minimize its detrimental impact on human health.

Metabolic Reprogramming in Gut Microbiota Exposed to Polystyrene Microplastics

Background: Microplastics (MPs) are small plastic fragments with diameters less than 5 mm in size and are prevalent in everyday essentials and consumables. Large global plastic production has now led to a flooding of MPs in our natural environment. Due to their detrimental impacts on the planet's ecosystems and potentially our health, MPs have emerged as a significant public health concern. In this pilot study, we hypothesize that MPs exposure will negatively affect gut microbiota composition and function, in which metabolic reprogramming plays an important role. Methods: Using in vitro experiments, three bacterial strains (Escherichia coli MG1655, Nissle 1917, and Lactobacillus rhamnosus) were selected to investigate the impacts of MPs exposure. The bacterial strains were individually cultured in an anaerobic chamber and exposed to 1 µm polystyrene MPs at various concentrations (0, 10, 20, 50, 100, and 500 µg/mL) in the culture medium. Results: MPs exposure reduced the growth of all three bacterial strains in a dose-dependent manner. Liquid chromatography mass spectrometry (LC-MS)-based untargeted metabolomics revealed significant differences in multiple metabolic pathways, such as sulfur metabolism and amino sugar and nucleotide sugar metabolism. In addition, we extracted gut microbiota from C57BL/6 mice, and 16S rRNA sequencing results showed a significant upregulation of Lactobacillales and a significant reduction in Erysipelotrichales due to MPs exposure. Furthermore, targeted and untargeted metabolomics corroborated the in vitro results and revealed alterations in microbial tryptophan metabolism and energy producing pathways, such as glycolysis/gluconeogenesis and the pentose phosphate pathway. Conclusions: These findings provide evidence that MPs exposure causes comprehensive changes to healthy gut microbiota, which may also provide insights into the mechanistic effects of MPs exposure in humans.

Discovery of a Gut Bacterial Pathway for Ergothioneine Catabolism

Ergothioneine is a diet-derived micronutrient for humans. However, enzymes involved in the catabolism of ergothioneine in human gut bacteria have not yet been identified. Herein, we characterize a sulfidogenic pathway for gut bacterial catabolism of this micronutrient, which involves an unprecedented reductive desulfurization reaction catalyzed by members of the xanthine oxidoreductase family (XOR), a class of molybdenum-containing flavoproteins. Notably, this is the first C-S bond cleavage reaction known to be catalyzed by XORs. Evidence for operation of this pathway was gained through in vitro reconstruction using heterologously produced enzymes derived from the human gut bacterium Blautia producta ATCC 27340. This catabolic activity enables B. producta ATCC 27340 to use ergothioneine as an alternative electron acceptor source. Homologues of the pathway enzymes are shown to be present not only in human gut bacteria but also in many environmental bacteria, suggesting the wide distribution of this catabolic strategy. In relation to the sulfur-containing metabolite, this discovery provides significant insight into biogeochemical sulfur cycling in diverse anoxic habitats beyond the human gut and, moreover, the design of new approaches for controlling intestinal hydrogen sulfide (H2S) production.

Cellular targets of cytotoxic copper phenanthroline complexes: a multimodal imaging quantitative approach in single PC3 cells

Metal complexes are emerging as promising alternatives to traditional platinum-based cancer treatments, offering reduced side effects. However, understanding their cellular uptake and distribution and quantifying their presence at the single cell level remains challenging. Advanced imaging techniques, including transmission electron microscopy, synchrotron radiation X-ray fluorescence, and energetic ion beam-based nuclear microscopy (scanning transmission ion microscopy, particle-induced X-ray emission, elastic backscattering spectrometry), allow detailed high-resolution visualization of structure and morphology, high sensitivity for elemental detection with quantification within single cells, and the construction of 3D models of metal distribution, positioning them as powerful tools for assessing the cellular uptake and compartmentalization of complexes. Three Cu(II) complexes [Cu(phen)2(H2O)](NO3)2 (1), [Cu(Me2phen)2(NO3)]NO3 (2) and [Cu(amphen)2(H2O)](NO3)2 (3), (phen = 1,10-phenanthroline, Me2phen = 4,7-dimethyl-1,10-phen, amphen = 5-amino-phen) were investigated for Cu uptake and distribution in PC3 prostate cancer cells. All complexes show significant Cu uptake regardless of media concentration. Cu concentrations in the cytoplasm and nucleus are similar between treatments. Complexes 1 and 3 concentrate Cu in the nuclear region and show a vesicle-like pattern around the nucleus, while 2 shows a dispersed cytoplasmic pattern with large vesicles. The 3D models confirm that Cu is not retained at the plasma membrane, with complex 1 targeting the nucleus and 2 remaining in the cytoplasm. These results highlight the importance of quantifying metal distribution and correlating it with structural changes to understand the relevance of the ligand in the mechanisms of cellular uptake and targeting, crucial for the development of effective metal-based cancer therapies.

Mechanistic Intimate Insights into the Role of Hydrogen Sulfide in Alzheimer's Disease: A Recent Systematic Review

In the rapidly evolving field of Alzheimer's Disease (AD) research, the intricate role of Hydrogen Sulfide (H2S) has garnered critical attention for its diverse involvement in both pathological substrates and prospective therapeutic paradigms. While conventional pathophysiological models of AD have primarily emphasized the significance of amyloid-beta (Aβ) deposition and tau protein hyperphosphorylation, this targeted systematic review meticulously aggregates and rigorously appraises seminal contributions from the past year elucidating the complex mechanisms of H2S in AD pathogenesis. Current scholarly literature accentuates H2S's dual role, delineating its regulatory functions in critical cellular processes-such as neurotransmission, inflammation, and oxidative stress homeostasis-while concurrently highlighting its disruptive impact on quintessential AD biomarkers. Moreover, this review illuminates the nuanced mechanistic intimate interactions of H2S in cerebrovascular and cardiovascular pathology associated with AD, thereby exploring avant-garde therapeutic modalities, including sulfurous mineral water inhalations and mud therapy. By emphasizing the potential for therapeutic modulation of H2S via both donors and inhibitors, this review accentuates the imperative for future research endeavors to deepen our understanding, thereby potentially advancing novel diagnostic and therapeutic strategies in AD.