D-mannose alleviates intervertebral disc degeneration through glutamine metabolism.

BACKGROUND: Intervertebral disc degeneration (IVDD) is a multifaceted condition characterized by heterogeneity, wherein the balance between catabolism and anabolism in the extracellular matrix of nucleus pulposus (NP) cells plays a central role. Presently, the available treatments primarily focus on relieving symptoms associated with IVDD without offering an effective cure targeting its underlying pathophysiological processes. D-mannose (referred to as mannose) has demonstrated anti-catabolic properties in various diseases. Nevertheless, its therapeutic potential in IVDD has yet to be explored. METHODS: The study began with optimizing the mannose concentration for restoring NP cells. Transcriptomic analyses were employed to identify the mediators influenced by mannose, with the thioredoxin-interacting protein (Txnip) gene showing the most significant differences. Subsequently, small interfering RNA (siRNA) technology was used to demonstrate that Txnip is the key gene through which mannose exerts its effects. Techniques such as colocalization analysis, molecular docking, and overexpression assays further confirmed the direct regulatory relationship between mannose and TXNIP. To elucidate the mechanism of action of mannose, metabolomics techniques were employed to pinpoint glutamine as a core metabolite affected by mannose. Next, various methods, including integrated omics data and the Gene Expression Omnibus (GEO) database, were used to validate the one-way pathway through which TXNIP regulates glutamine. Finally, the therapeutic effect of mannose on IVDD was validated, elucidating the mechanistic role of TXNIP in glutamine metabolism in both intradiscal and orally treated rats. RESULTS: In both in vivo and in vitro experiments, it was discovered that mannose has potent efficacy in alleviating IVDD by inhibiting catabolism. From a mechanistic standpoint, it was shown that mannose exerts its anti-catabolic effects by directly targeting the transcription factor max-like protein X-interacting protein (MondoA), resulting in the upregulation of TXNIP. This upregulation, in turn, inhibits glutamine metabolism, ultimately accomplishing its anti-catabolic effects by suppressing the mitogen-activated protein kinase (MAPK) pathway. More importantly, in vivo experiments have further demonstrated that compared with intradiscal injections, oral administration of mannose at safe concentrations can achieve effective therapeutic outcomes. CONCLUSIONS: In summary, through integrated multiomics analysis, including both in vivo and in vitro experiments, this study demonstrated that mannose primarily exerts its anti-catabolic effects on IVDD through the TXNIP-glutamine axis. These findings provide strong evidence supporting the potential of the use of mannose in clinical applications for alleviating IVDD. Compared to existing clinically invasive or pain-relieving therapies for IVDD, the oral administration of mannose has characteristics that are more advantageous for clinical IVDD treatment.

d-Mannose for Prevention of Recurrent Urinary Tract Infection Among Women: A Randomized Clinical Trial.

Importance: Recurrent urinary tract infection (UTI) is a common debilitating condition in women, with limited prophylactic options. d-Mannose has shown promise in trials based in secondary care, but effectiveness in placebo-controlled studies and community settings has not been established. Objective: To determine whether d-mannose taken for 6 months reduces the proportion of women with recurrent UTI experiencing a medically attended UTI. Design, Setting, and Participants: This 2-group, double-blind randomized placebo-controlled trial took place across 99 primary care centers in the UK. Participants were recruited between March 28, 2019, and January 31, 2020, with 6 months of follow-up. Participants were female, 18 years or older, living in the community, and had evidence in their primary care record of consultations for at least 2 UTIs in the preceding 6 months or 3 UTIs in 12 months. Invitation to participate was made by their primary care center. A total of 7591 participants were approached, 830 responded, and 232 were ineligible or did not proceed to randomization. Statistical analysis was reported in December 2022. Intervention: Two grams daily of d-mannose powder or matched volume of placebo powder. Main Outcomes and Measures: The primary outcome measure was the proportion of women experiencing at least 1 further episode of clinically suspected UTI for which they contacted ambulatory care within 6 months of study entry. Secondary outcomes included symptom duration, antibiotic use, time to next medically attended UTI, number of suspected UTIs, and UTI-related hospital admissions. Results: Of 598 women eligible (mean [range] age, 58 [18-93] years), 303 were randomized to d-mannose (50.7%) and 295 to placebo (49.3%). Primary outcome data were available for 583 participants (97.5%). The proportion contacting ambulatory care with a clinically suspected UTI was 150 of 294 (51.0%) in the d-mannose group and 161 of 289 (55.7%) in the placebo group (risk difference, -5%; 95% CI, -13% to 3%; P = .26). Estimates were similar in per protocol analyses, imputation analyses, and preplanned subgroups. There were no statistically significant differences in any secondary outcome measures. Conclusions and Relevance: In this randomized clinical trial, daily d-mannose did not reduce the proportion of women with recurrent UTI in primary care who experienced a subsequent clinically suspected UTI. d-Mannose should not be recommended for prophylaxis in this patient group. Trial Registration: isrctn.org Identifier: ISRCTN13283516.

Integrated application of transcriptomics and metabolomics provides insight into the mechanism of Eimeria tenella resistance to maduramycin.

Avian coccidiosis, caused by Eimeria parasites, continues to devastate the poultry industry and results in significant economic losses. Ionophore coccidiostats, such as maduramycin and monensin, are widely used for prophylaxis of coccidiosis in poultry. Nevertheless, their efficacy has been challenged by widespread drug resistance. However, the underlying mechanisms have not been revealed. Understanding the targets and resistance mechanisms to anticoccidials is critical to combat this major parasitic disease. In the present study, maduramycin-resistant (MRR) and drug-sensitive (DS) sporozoites of Eimeria tenella were purified for transcriptomic and metabolomic analysis. The transcriptome analysis revealed 5016 differentially expressed genes (DEGs) in MRR compared to DS, and KEGG pathway enrichment analysis indicated that DEGs were involved in spliceosome, carbon metabolism, glycolysis, and biosynthesis of amino acids. In the untargeted metabolomics assay, 297 differentially expressed metabolites (DEMs) were identified in MRR compared to DS, and KEGG pathway enrichment analysis indicated that these DEMs were involved in 10 pathways, including fructose and mannose metabolism, cysteine and methionine metabolism, arginine and proline metabolism, and glutathione metabolism. Targeted metabolomic analysis revealed 14 DEMs in MRR compared to DS, and KEGG pathway analysis indicated that these DEMs were involved in 20 pathways, including fructose and mannose metabolism, glycolysis/gluconeogenesis, and carbon metabolism. Compared to DS, energy homeostasis and amino acid metabolism were differentially regulated in MRR. Our results provide gene and metabolite expression landscapes of E. tenella following maduramycin induction. This study is the first work involving integrated transcriptomic and metabolomic analyses to identify the key pathways to understand the molecular and metabolic mechanisms underlying drug resistance to polyether ionophores in coccidia.

Guanosine diphosphate-mannose suppresses homologous recombination repair and potentiates antitumor immunity in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor prognosis. TNBCs with high homologous recombination deficiency (HRD) scores benefit from DNA-damaging agents, including platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors, whereas those with low HRD scores still lack therapeutic options. Therefore, we sought to exploit metabolic alterations to induce HRD and sensitize DNA-damaging agents in TNBCs with low HRD scores. We systematically analyzed TNBC metabolomics and identified a metabolite, guanosine diphosphate (GDP)-mannose (GDP-M), that impeded homologous recombination repair (HRR). Mechanistically, the low expression of the upstream enzyme GDP-mannose-pyrophosphorylase-A (GMPPA) led to the endogenous up-regulation of GDP-M in TNBC. The accumulation of GDP-M in tumor cells further reduced the interaction between breast cancer susceptibility gene 2 (BRCA2) and ubiquitin-specific peptidase 21 (USP21), which promoted the ubiquitin-mediated degradation of BRCA2 to inhibit HRR. Therapeutically, we illustrated that the supplementation of GDP-M sensitized DNA-damaging agents to impair tumor growth in both in vitro (cancer cell line and patient-derived organoid) and in vivo (xenograft in immunodeficient mouse) models. Moreover, the combination of GDP-M with DNA-damaging agents activated STING-dependent antitumor immunity in immunocompetent syngeneic mouse models. Therefore, GDP-M supplementation combined with PARP inhibition augmented the efficacy of anti-PD-1 antibodies. Together, these findings suggest that GDP-M is a crucial HRD-related metabolite and propose a promising therapeutic strategy for TNBCs with low HRD scores using the combination of GDP-M, PARP inhibitors, and anti-PD-1 immunotherapy.

Mannose attenuates intestinal epithelial tight junction damage in experimental colitis mice by activating the AXIN-AMPK pathway.

Mannose is a unique natural sugar that can be found in a variety of fruits and vegetables. During the past decades, mannose has been reported to be effective in promoting immune tolerance and suppressing inflammatory diseases. Metabolic dysfunction and altered inflammation have clear implications for the development and progression of inflammatory diseases. Herein, we intended to reveal the molecular mechanism of mannose in protecting against intestinal epithelial damage in experimental colitis. We showed that mannose treatment significantly attenuated dextran sodium sulfate (DSS)-induced intestinal barrier damage. The AMPK pathway was responsible for the mannose-mediated protective effect in DSS-induced intestinal epithelial damage. Mechanistically, mannose promoted the axis inhibition protein (AXIN)-based AMPK activation, thereby preventing mitochondrial dysfunction and tight junction disruption in response to the DSS challenge. Cumulatively, the results indicate the use of mannose as a novel approach to treat IBD and other diseases involving tight junction dysfunction. The therapeutic effect of mannose is related to its regulatory function in AMPK pathway activation.

Cellular signaling in the hypoxic cancer microenvironment: Implications for drug resistance and therapeutic targeting.

The rewiring of cellular metabolism is a defining characteristic of cancer, as tumor cells adapt to acquire essential nutrients from a nutrient-poor environment to sustain their viability and biomass. While hypoxia has been identified as a major factor depriving cancer cells of nutrients, recent studies have revealed that cancer cells distant from supporting blood vessels also face nutrient limitations. To overcome this challenge, hypoxic cancer cells, which heavily rely on glucose as an energy source, employ alternative pathways such as glycogen metabolism and reductive carboxylation of glutamine to meet their energy requirements for survival. Our preliminary studies, alongside others in the field, have shown that under glucose-deficient conditions, hypoxic cells can utilize mannose and maltose as alternative energy sources. This review aims to comprehensively examine the hypoxic cancer microenvironment, its association with drug resistance, and potential therapeutic strategies for targeting this unique niche. Furthermore, we will critically evaluate the current literature on hypoxic cancer microenvironments and explore state-of-the-art techniques used to analyze alternate carbohydrates, specifically mannose and maltose, in complex biological fluids. We will also propose the most effective analytical methods for quantifying mannose and maltose in such biological samples. By gaining a deeper understanding of the hypoxic cancer cell microenvironment and its role in drug resistance, novel therapeutic approaches can be developed to exploit this knowledge.

D-mannose induces TFE3-dependent lysosomal degradation of EGFR and inhibits the progression of NSCLC.

In non-small cell lung cancer (NSCLC), the overexpression or abnormal activation of epidermal growth factor receptor (EGFR) is associated with tumor progression and drug resistance. EGFR tyrosine kinase inhibitors (TKIs) are currently the first-line treatment of NSCLC. However, patients inevitably acquired EGFR TKIs resistance mutations, which led to disease progression, so it is urgent to find new treatment. Here, we report that D-mannose up-regulates lysosomal activity by enhancing TFE3-mediated lysosomal biogenesis, thereby increasing the degradation of EGFR and significantly down-regulating its protein level. Therefore, D-mannose significantly inhibited the proliferation, migration and invasion of wild-type EGFR (WT-EGFR) and EGFR mutant cells (E746-A750 deletion, L858R and T790M mutations) in vitro. Oral administration of D-mannose strongly inhibited tumor growth in mice, showing similar effects with osimertinib. Taken together, these data suggest that D-mannose may represent a new strategy for clinical treatment of NSCLC.

Biological function, regulatory mechanism, and clinical application of mannose in cancer.

Studies examining the regulatory roles and clinical applications of monosaccharides other than glucose in cancer have been neglected. Mannose, a common type of monosaccharide found in human body fluids and tissues, primarily functions in protein glycosylation rather than carbohydrate metabolism. Recent research has demonstrated direct anticancer effects of mannose in vitro and in vivo. Simply supplementing cell culture medium or drinking water with mannose achieved these effects. Moreover, mannose enhances the effectiveness of current cancer treatments including chemotherapy, radiotherapy, targeted therapy, and immune therapy. Besides the advancements in basic research on the anticancer effects of mannose, recent studies have reported its application as a biomarker for cancer or in the delivery of anticancer drugs using mannose-modified drug delivery systems. This review discusses the progress made in understanding the regulatory roles of mannose in cancer progression, the mechanisms underlying its anticancer effects, and its current application in cancer diagnosis and treatment.

Empagliflozin improves insulin sensitivity in patients with recent acute coronary syndrome and newly detected dysglycaemia : Experiences from the randomized, controlled SOCOGAMI trial.

BACKGROUND: Empagliflozin reduces the risk of cardiovascular disease (CVD) in patients with type 2 diabetes (T2DM) and high cardiovascular risk via mechanisms which have not been fully explained. The mechanisms of such benefit have not been fully understood, and whether empagliflozin can be safely administered as first-line treatment in patients with CVD at the initial stages of glycaemic perturbations remains to be established. We investigated the effects of empagliflozin on insulin resistance, insulin sensitivity and ß-cell function indexes in patients with a recent acute coronary event and newly detected dysglycaemia, i.e., impaired glucose tolerance (IGT) or T2DM. METHODS: Forty-two patients (mean age 67.5 years, 19% females) with a recent myocardial infarction (n = 36) or unstable angina (n = 6) and newly detected dysglycaemia were randomized to either empagliflozin 25 mg daily (n = 20) or placebo (n = 22). Patients were investigated with stress-perfusion cardiac magnetic resonance imaging before randomization, 7 months after the start of study drug and 3 months following its cessation. Indexes of insulin resistance, sensitivity and ß-cell function were calculated based on glucose and insulin values from 2-hour oral glucose tolerance tests (OGTT) and fasting C-peptide. The differences in glucose, insulin, C-peptide, mannose levels and indexes between the two groups were computed by repeated measures ANOVA including an interaction term between the treatment allocation and the time of visit. RESULTS: After 7 months, empagliflozin significantly decreased glucose and insulin values during the OGTT, whereas C-peptide, mannose and HbA1c did not differ. Empagliflozin significantly improved insulin sensitivity indexes but did not impact insulin resistance and ß-cell function. After cessation of the drug, all indexes returned to initial levels. Insulin sensitivity indexes were inversely correlated with left ventricular mass at baseline. CONCLUSIONS: Empagliflozin improved insulin sensitivity indexes in patients with a recent coronary event and drug naïve dysglycaemia. These findings support the safe use of empagliflozin as first-line glucose-lowering treatment in patients at very high cardiovascular risk with newly diagnosed dysglycaemia. TRIAL REGISTRATION NUMBER: EudraCT number 2015-004571-73.

Literature Review of Ascorbic Acid, Cranberry, and D-mannose for Urinary Tract Infection Prophylaxis in Older People.

Background Urinary tract infections (UTIs) are the most prevalent infections in older patients with the potential for morbidity and mortality. Antibiotics are not generally recommended for UTI prophylaxis in this population. There is interest among the public and health providers to try over-the-counter products, such as cranberry, D-mannose, and vitamin C. The objective of this analysis was to review the literature for the efficacy and tolerability of these supplements in older individuals. Methods A literature review was conducted on PubMed using the search terms urinary tract infection or UTI, prevention/prophylaxis, cranberry, D-mannose, vitamin C/ascorbic acid. Few studies were conducted among older people; therefore, the authors included studies of all adults who had recurrent UTIs or were at increased risk of UTIs. Level (quality) of evidence were determined using the ACC/AHA Clinical Practice Guideline Recommendation Classification System. Results A total of 24 studies were included. This review captured all studies in previous reviews as well as recent publications. The authors determined that there were limited data for D-mannose and vitamin C, and randomized data for cranberry as defined by the classification system. Conclusions The three supplements reviewed appear not to be strongly supported by clinical data. For those who are interested in trying these products despite the lack of robust evidence for clinical efficacy, it may be helpful to know that the studies included in this review did not identify any clinically important signs of harm, to the extent that safety data were documented and reported.

d-mannose blocks the interaction between keratinocytes and Th17 cells to alleviate psoriasis by inhibiting HIF-1α/CCL20 in mice.

Psoriasis is an autoimmune chronic inflammatory skin disease with an unclear pathogenesis that is difficult to cure, causing serious physical and mental burdens for patients. Previous research showed that a mutually reinforcing vicious cycle caused by keratinocytes (KC) and a variety of immune cells plays an important role in psoriatic inflammation. d-Mannose, a widely distributed metabolite in the body, has been found to treat several metabolic diseases, but its impact on psoriasis remains unknown. Our study aims to investigate the effects of d-mannose on psoriasis and its specific mechanism. Here, we found that d-mannose alleviates psoriasis in mice both as oral and topical agents. Specifically, d-mannose down-regulated the expression of hypoxia-inducible factor 1A(HIF-1α) and inhibited the expression of chemokine CCL20 in keratinocytes, thereby inhibiting the local infiltration of Th17 cells and breaking the cycle of keratinocytes-Th17 cells. Overall, our study indicates that d-mannose alleviates cutaneous inflammation in psoriasis by inhibiting the HIF-1α/CCL20/Th17 cells axis, and d-mannose has the potential to be used as an oral and topical agent in the treatment of psoriasis.

A Randomized Controlled Trial Comparing a New D-Mannose-based Dietary Supplement to Placebo for the Treatment of Uncomplicated Escherichia coli Urinary Tract Infections.

BACKGROUND: The rise in antimicrobial resistance means that alternative approaches for the treatment and prevention of urinary tract infection (UTIs) are required. OBJECTIVE: To evaluate the safety and efficacy of a D-mannose-based dietary supplement (D-mannose, citric acid, prebiotic fibers, Astragalus, and dandelion; DAPAD complex) for the treatment of uncomplicated acute E. coli UTIs. DESIGN, SETTING, AND PARTICIPANTS: This was a single-center, randomized, double-blind, placebo-controlled trial conducted from April 2021 to October 2021 in Rajalakshmi Hospital and Research Centre (Bangalore, India). The participants were nonmenopausal women with an acute uncomplicated E. coli UTI. UTI was diagnosed according to the presence of at least one urinary symptom and bacteriuria (>100 000 CFU/ml). INTERVENTION: The DAPAD complex was administered twice a day for 5 d, with phenazopyridine and alkalizing agents as the standard of care (SOC). The control group received placebo with SOC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Subjective (clinical resolution/response) and objective (midstream bacteriuria) outcomes were evaluated at the end of therapy (day 6) and at day 35 of follow-up. Adverse events were recorded. Categorical variables were analyzed using χ2 and Fisher's exact tests; a p value <0.05 was considered significant. RESULTS AND LIMITATIONS: Seventy women were enrolled and equally randomized to the two groups. Clinical resolution was higher in the DAPAD group at 6 d (34.3% vs 0%; p < 0.0001) and 35 d from baseline (88.6% vs 20%, p < 0.0001). At day 35, no patients in the DAPAD group had moderate or severe symptoms, whereas 25.7% (nine/35) and 11.4% (four/35) of patients in the placebo group had moderate and severe symptoms, respectively. Bacteriological resolution was also higher in the DAPAD group at day 6 (85.7% vs 14.3%; p < 0.0001) and day 35 (100% vs 40%; p < 0.0001). Three mild adverse events (4.26%) unrelated to the investigated product were recorded, all of which were medically treated. CONCLUSIONS: The DAPAD complex dietary supplement is effective and safe for treatment of acute uncomplicated E. coli UTIs. PATIENT SUMMARY: Our results show that for nonmenopausal women with an uncomplicated Escherichia coli urinary tract infection, those treated with a dietary supplement (containing D-mannose, citric acid, prebiotic fibers, Astragalus, and dandelion) had a higher rate of clinical resolution or response than women who received a placebo.

Mannose metabolism normalizes gut homeostasis by blocking the TNF-α-mediated proinflammatory circuit.

Mannose is a naturally occurring sugar widely consumed in the daily diet; however, mechanistic insights into how mannose metabolism affects intestinal inflammation remain lacking. Herein, we reported that mannose supplementation ameliorated colitis development and promoted colitis recovery. Macrophage-secreted inflammatory cytokines, particularly TNF-α, induced pathological endoplasmic reticulum stress (ERS) in intestinal epithelial cells (IECs), which was prevented by mannose via normalization of protein N-glycosylation. By preserving epithelial integrity, mannose reduced the inflammatory activation of colonic macrophages. On the other hand, mannose directly suppressed macrophage TNF-α production translationally by reducing the glyceraldehyde 3-phosphate level, thus promoting GAPDH binding to TNF-α mRNA. Additionally, we found dysregulated mannose metabolism in the colonic mucosa of patients with inflammatory bowel disease. Finally, we revealed that activating PMM2 activity with epalrestat, a clinically approved drug for the treatment of diabetic neuropathy, elicited further sensitization to the therapeutic effect of mannose. Therefore, mannose metabolism prevents TNF-α-mediated pathogenic crosstalk between IECs and intestinal macrophages, thereby normalizing aberrant immunometabolism in the gut.

d-mannosuria levels measured 1 h after d-mannose intake can select out favorable responders: A pilot study.

BACKGROUND: d-mannose is used as preventive measure against recurrent urinary tract infections (RUTIs). We studied d-mannosuria after a challenge test to identify favorable responders that could be targeted for long-term preventive therapy. MATERIAL AND METHODS: Following institutional review board approval, women attending a specialized tertiary care center urology clinic with a history of RUTIs were invited to participate by providing a urine sample (baseline), followed by the intake of home-dose d-mannose, and a second urine sample 1 h later (post). Urine samples were processed according to a d-mannosuria assay technique reported previously by our group. d-mannose concentrations were normalized to urinary creatinine. RESULTS: From July 2020 to March 2021, 26 patients met study criteria. Thirteen had a lower or unchanged ratio of baseline to post d-mannose, whereas 13 were responders. Among 19 taking 2 g, 12 had a lower or unchanged trend and 7 were responders with >20% increase in the d-mannose/creatinine ratio. Comparison of urinary baseline d-mannose/creatinine ratios was significantly different between the responder (mean = 0.337 ± 0.158) and nonresponder (mean = 0.692 ± 0.444; p = 0.016) groups. Urinary post d-mannose/creatinine ratios did not significantly differ between the two groups (p = 0.46). d-mannose-naïve patients had few responders, and age and urinary creatinine did not affect the findings. CONCLUSION: This preliminary study on d-mannose challenge tests indicates a urine response if urinary d-mannose/creatinine ratio is low, which it was in some women with a history of RUTIs.

Dual Rifampicin and Isoniazid Mannose-Decorated Lipopolysaccharide Nanospheres for Macrophage- Targeted Lung Delivery.

BACKGROUND: Currently, the treatment protocols for tuberculosis (TB) have several challenges, such as inconsistent oral bioavailability, dose-related adverse effects, and off-target drug toxicity. METHODS: This research reports the design and characterization of rifampicin (RIF) and isoniazid (INH) loaded hybrid lipid-polysaccharide nanoparticles using the solvent injection method, and demonstrated the influence of conjugated mannosyl residue on macrophage targeting and intracellular drug delivery capacity. RESULTS: The nanospheres, herein called mannose-decorated lipopolysaccharide nanoparticles, were spherical in shape, exhibiting average sizes less than 120 nm (PDI<0.20) and positive zeta potentials. Drug encapsulation was greater than 50% for rifampicin and 60% for isoniazid. The pH-responsive drug release was sustained over a 48-hour period and preferentially released more rifampicin/isoniazid in a simulated acidic phagolysosomal environment (pH 4.8) than in a simulated physiological medium. TGA and FTIR analysis confirmed successful mannose-grafting on nanoparticle surface and optimal degree of mannosylation was achieved within 48-hour mannose-lipopolysaccharide reaction time. The mannosylated nanoparticles were biocompatible and demonstrated a significant improvement towards uptake by RAW 264.7 cells, producing higher intracellular RIF/INH accumulation when compared to the unmannosylated nanocarriers. CONCLUSION: Overall, the experimental results suggested that mannose-decorated lipopolysaccharide nanosystems hold promise towards safe and efficacious macrophage-targeted delivery of anti-TB therapeutics.

D-Mannose ameliorates DNCB-induced atopic dermatitis in mice and TNF-α-induced inflammation in human keratinocytes via mTOR/NF-κB pathway.

D-mannose is a C-2 epimer of glucose, widely distributed in nature. Atopic dermatitis (AD) is a chronic inflammatory disease characterized by repetitious itching. The present study aimed to explore the protective effect and the underlying mechanism of D-mannose against the development of atopic dermatitis. We tested the effect of D-mannose by establishing DNCB (2,4-dinitrochlorobenzene)-induced AD mice models in vivo and culturing keratinocytes (HaCaT and NHEK) in vitro. The skin lesion severity was evaluated by histochemical staining. Cytokine expression levels were measured by real-time PCR and ELISA assay. The expression of the mammalian target of rapamycin (mTOR)/ nuclear transcription factor κB (NF-κB)-signaling-related molecules were determined by western blotting. Here, we found that topical supplementation of D-mannose remarkably attenuated skin lesions and recovered skin barrier function in AD mice model induced by DNCB. Furthermore, in vivo and in vitro experiments indicated that D-mannose inhibited tumor necrosis factor-α (TNF-α)-mediated increased expression of inflammatory cytokines. D-mannose also markedly downregulated TNF-α-stimulated activation of mTOR/NF-κB signaling pathway that was crucial for regulating the inflammatory condition. However, these effects were abolished by treatment with inhibitors of mTOR or NF-κB in HaCaT and NHEK. As far as we know, this is the first study uncovering the effective role of D-mannose via skin topical application. We found that D-mannose plays a regulatory role on inflammatory keratinocytes, suggesting its therapeutic utilization as a potential drug against atopic dermatitis.

D-mannose for preventing and treating urinary tract infections.

BACKGROUND: Urinary tract infections (UTIs) are very common, affecting more than 7 million people worldwide. Whilst many people may only experience a single episode in their lifetime and are generally responsive to standard antibiotics, a significant proportion of adults and children (approximately 15% to 25%) are chronic symptomatic UTI sufferers. Certain population groups are at greater risk than others, such as immunosuppressed and people with chronic kidney disease. D-mannose is a sugar part of normal human metabolism found within most diets. The mechanism of action is to prevent bacterial adherence to the uroepithelial cells. The D-mannose-based inhibitors can block uropathogenic Escherichia coli adhesion and invasion of the uroepithelial cells. The bacteria are then understood to essentially be eliminated by urination. Early pilot studies on animals and humans have trialled concentrated forms of D-mannose (tablets or sachets) in doses ranging from 200 mg up to 2 to 3 g and found possible efficacy in reducing UTI symptoms or recurrence. Although the anti-adhesive effects of D-mannose have been well-established, only recently have we seen a small number of pilot studies and small clinical trials conducted. OBJECTIVES: To assess the benefits and harms of D-mannose for preventing and treating UTIs in adults and children. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies up to 22 February 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: We included RCTs measuring and reporting the effect of D-mannose, in any combination and any formulation, to prevent or treat UTIs in adults and children, females and males, in any setting (including perioperative). Authors independently assessed the retrieved titles and abstracts and, where necessary, the full text to determine which satisfied the inclusion criteria. DATA COLLECTION AND ANALYSIS: Data extraction was independently carried out by two authors using a standard data extraction form. Methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Data entry was carried out by one author and cross-checked by another author. The certainty of the evidence was assessed using the GRADE approach. MAIN RESULTS: We included seven RCTs (719 participants) in adult females and males who had either acute cystitis or a history of recurrent (at least two episodes in six months or three episodes in 12 months) UTIs (symptomatic or asymptomatic). Two were prevention studies, four were prevention and treatment studies (two perioperative and one in people with multiple sclerosis), and one was a treatment study. Time periods ranged from 15 days to six months. No two studies were comparable (by dose or treatments), and we could not undertake meta-analyses. Individual studies reported no clear evidence to determine whether D-mannose is more or less effective in preventing or treating UTIs. D-mannose (2 g) had uncertain effects on symptomatic and bacteriuria-confirmed UTIs when compared to no treatment (1 study, 205 participants; very low certainty evidence) and antibiotics (nitrofurantoin 50 mg) (1 study, 206 participants; very low certainty evidence). D-mannose, in combination with herbal supplements, had uncertain effects on symptomatic and bacteria-confirmed UTI and pain when compared to no treatment (1 study, 40 participants; very low certainty evidence). D-mannose 500 mg plus supplements (N-acetylcysteine and Morinda citrifolia fruit extract) had uncertain effects on symptomatic and bacteriuria-confirmed UTIs when compared to an antibiotic (prulifloxacin 400 mg) (1 study, 75 participants; very low certainty evidence). Adverse events were very few and poorly reported; none were serious (mostly diarrhoea and vaginal burning). Overall, the quality of the evidence is poor. Most studies were judged to have unclear or high risk of bias across most domains. Data was sparse and addressed very few outcomes. The GRADE evaluation was rated as very low certainty evidence due to very serious limitations in the study design or execution (high risk of bias across all studies) and sparse data (single study data and small sample sizes). AUTHORS' CONCLUSIONS: There is currently little to no evidence to support or refute the use of D-mannose to prevent or treat UTIs in all populations. This review highlights the severe lack of high-quality RCTs testing the efficacy of D-mannose for UTIs in any population. Despite UTIs being one of the most common adult infections (affecting 50% of women at least once in their lifetime) and the growing global antimicrobial resistance, we found very few studies that adequately test this alternative treatment. Future research in this field requires, in the first instance, a single adequately powered RCT comparing D-mannose with placebo.

The Interaction between DNMT1 and High-Mannose CD133 Maintains the Slow-Cycling State and Tumorigenic Potential of Glioma Stem Cell.

The quiescent/slow-cycling state preserves the self-renewal capacity of cancer stem cells (CSCs) and leads to the therapy resistance of CSCs. The mechanisms maintaining CSCs quiescence remain largely unknown. Here, it is demonstrated that lower expression of MAN1A1 in glioma stem cell (GSC) resulted in the formation of high-mannose type N-glycan on CD133. Furthermore, the high-mannose type N-glycan of CD133 is necessary for its interaction with DNMT1. Activation of p21 and p27 by the CD133-DNMT1 interaction maintains the slow-cycling state of GSC, and promotes chemotherapy resistance and tumorigenesis of GSCs. Elimination of the CD133-DNMT1 interaction by a cell-penetrating peptide or MAN1A1 overexpression inhibits the tumorigenesis of GSCs and increases the sensitivity of GSCs to temozolomide. Analysis of glioma samples reveals that the levels of high-mannose type N-glycan are correlated with glioma recurrence. Collectively, the high mannose CD133-DNMT1 interaction maintains the slow-cycling state and tumorigenic potential of GSC, providing a potential strategy to eliminate quiescent GSCs.

Synthesis, Renal Clearance, and Photothermal Therapy Based on the Self-Assembly of a Nanomedicine Consisting of Quaterrylene Bisimide and Glycocluster Conjugates.

Renal-clearable nanomedicines are considered the next generation of nanomedicines, and show potential application for future clinical translations. However, it is important to determine whether self-assembly can form large aggregates that accrue in tumors and then tailor the size of these assemblies to be excreted renally. In this paper, a renal-clearable nanomedicine based on quanterrylene bisimide-mannose conjugates (QDI-Man) was developed. QDI-Man showed a high renal clearance efficiency of 80.31 ± 2.85% in mice. We confirmed that the self-assembly of QDI-Man exhibited a dynamic adjustment process through the renal filtration thresholds, that is, "aggregation → self-regulating the aggregate size through the renal filtration thresholds → reaggregating into aggregates". Benefiting from the modification of mannose-based glycoclusters, QDI-Man showed selective photothermal therapy because of the mannose receptors overexpressed in breast cancer cells, and showed good photothermal therapy in mice. This paper developed a dynamic adjustment theory for effective renal clearance based on organic self-assembly.