Regulation of immunological and inflammatory functions by biotin

Genome sequencing enables diagnosis and treatment of SLC5A6 neuropathy

The sodium-dependent multivitamin transporter encoded by SLC5A6 is responsible for uptake of biotin, pantothenic acid, and α-lipoic acid. Thirteen individuals from eight families are reported with pathogenic biallelic SLC5A6 variants. Phenotype ranges from multisystem metabolic disorder to childhood-onset peripheral motor neuropathy. We report three additional affected individuals with biallelic SLC5A6 variants. In Family A, a male proband (AII:1) presenting in early childhood with gross motor regression, motor axonal neuropathy, recurrent cytopenia and infections, and failure to thrive was diagnosed at 12 years of age via genome sequencing (GS) with a paternal NM_021095.4:c.393+2T>C variant and a maternal c.1285A>G p.(Ser429Gly) variant. An uncle with recurrent cytopenia and peripheral neuropathy was subsequently found to have the same genotype. We also report an unrelated female with peripheral neuropathy homozygous for the c.1285A>G p.(Ser429Gly) recurrent variant identified in seven reported cases, including this study. RT-PCR studies on blood mRNA from AII:1 showed c.393+2T>C caused mis-splicing with all canonically spliced transcripts in AII:1 containing the c.1285A>G variant. SLC5A6 mRNA expression in AII:1 fibroblasts was ~50% of control levels, indicative of nonsense-mediated decay of mis-spliced transcripts. Biotin uptake studies on AII:1 fibroblasts, expressing the p.(Ser429Gly) variant, showed an ~90% reduction in uptake compared to controls. Targeted treatment of AII:1 with biotin, pantothenic acid, and lipoic acid resulted in clinical improvement. Health Economic analyses showed implementation of GS as an early investigation could have saved $ AUD 105,988 and shortened diagnostic odyssey and initiation of treatment by up to 7 years.

Deciphering the interplay of gut microbiota and metabolomics in retinal vein occlusion

This study aims to explore the link between retinal vein occlusion (RVO), a blinding ocular condition, and alterations in gut microbiota composition, to offer insights into the pathogenesis of RVO. Fecal samples from 25 RVO patients and 11 non-RVO individuals were analyzed using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS). Significant differences in the abundance of gut microbial species were noted between RVO and non-RVO groups. At the phylum level, the RVO group showed an elevation in the ratio of Firmicutes to Bacteroidetes. At the genus level, the RVO group showed higher abundance in Escherichia_Shigella (P < 0.05) and less abundance in Parabacteroides (P < 0.01) than the non-RVO group. Functional predictions indicated reduced folate synthesis, biotin metabolism, and oxidative phosphorylation, with an increase in butyric acid metabolism in the RVO group. LC-MS analysis showed significant differences in purine metabolism, ABC transporters, and naphthalene degradation pathways, especially purine metabolism. Pearson correlation analysis revealed significant associations between bacterial genera and fecal metabolites. Enrichment analysis highlighted connections between specific metabolites and bacterial genera. The findings showed that the dysregulation of gut microbiota was observed in RVO patients, suggesting the gut microbiota as a potential therapeutic target. Modulating the gut microbiota could be a novel strategy for managing RVO and improving patient outcomes. Furthermore, the study findings suggest the involvement of gut microbial dysbiosis in RVO development, underscoring the significance of understanding its pathogenesis for effective treatment development.

IMPORTANCE

Retinal vein occlusion (RVO) is a blinding ocular condition, and understanding its pathogenesis is crucial for developing effective treatments. This study demonstrates significant differences in gut microbiota composition between RVO patients and non-RVO individuals, implicating the involvement of gut microbial dysbiosis in RVO development. Functional predictions and metabolic profiling provide insights into the underlying mechanisms, highlighting potential pathways for therapeutic intervention. These findings suggest that modulating the gut microbiota might be a promising strategy for managing RVO and improving patient outcomes.

Arginine Biosynthesis Mediates Wulingzhi Extract Resistance to Busulfan-Induced Male Reproductive Toxicity

Busulfan, an indispensable medicine in cancer treatment, can cause serious reproductive system damage to males as a side effect of its otherwise excellent therapeutic results. Its widespread use has also caused its accumulation in the environment and subsequent ecotoxicology effects. As a Chinese medicine, Wulingzhi (WLZ) has the effects of promoting blood circulation and improving female reproductive function. However, the potential effects of WLZ in male reproduction and in counteracting busulfan-induced testis damage, as well as its probable mechanisms, are still ambiguous. In this study, busulfan was introduced in a mouse model to evaluate its production of the testicular damage. The components of different WLZ extracts were compared using an untargeted metabolome to select extracts with greater efficacy, which were further confirmed in vivo. Here, we demonstrate abnormal spermatogenesis and low sperm quality in busulfan-injured testes. The WLZ extracts showed a strong potential to rehabilitate the male reproductive system; this effect was more prominent in room-temperature extracts. Additionally, both water and ethanol WLZ extracts at room temperature alleviated various busulfan-induced adverse effects. In particular, WLZ recovered spermatogenesis, re-activated arginine biosynthesis, and alleviated the increased oxidative stress and inflammation in the testis, ultimately reversing the busulfan-induced testicular injury. Collectively, these results suggest a promising approach to protecting the male reproductive system from busulfan-induced adverse side effects, as well as those of other similar anti-cancer drugs.

Meta-analysis of shotgun sequencing of gut microbiota in Parkinson's disease

We aimed to identify gut microbial features in Parkinson's disease (PD) across countries by meta-analyzing our fecal shotgun sequencing dataset of 94 PD patients and 73 controls in Japan with five previously reported datasets from USA, Germany, China1, China2, and Taiwan. GC-MS and LC-MS/MS assays were established to quantify fecal short-chain fatty acids (SCFAs) and fecal polyamines, respectively. α-Diversity was increased in PD across six datasets. Taxonomic analysis showed that species Akkermansia muciniphila was increased in PD, while species Roseburia intestinalis and Faecalibacterium prausnitzii were decreased in PD. Pathway analysis showed that genes in the biosyntheses of riboflavin and biotin were markedly decreased in PD after adjusting for confounding factors. Five out of six categories in carbohydrate-active enzymes (CAZymes) were decreased in PD. Metabolomic analysis of our fecal samples revealed that fecal SCFAs and polyamines were significantly decreased in PD. Genes in the riboflavin and biotin biosyntheses were positively correlated with the fecal concentrations of SCFAs and polyamines. Bacteria that accounted for the decreased riboflavin biosynthesis in Japan, the USA, and Germany were different from those in China1, China2, and Taiwan. Similarly, different bacteria accounted for decreased biotin biosynthesis in the two country groups. We postulate that decreased SCFAs and polyamines reduce the intestinal mucus layer, which subsequently facilitates the formation of abnormal α-synuclein fibrils in the intestinal neural plexus in PD, and also cause neuroinflammation in PD.

Accurate determination of Biotinidase activity in serum by HPLC and its utilization as second tier test for the confirmation of initial positive newborn screening results

Diagnosis of Biotinidase deficiency (BTD) is extremely important to avoid several neurodevelopmental problems in early childhood. Colorimetric and fluorometric methods lack specificity and selectivity due to several interferences resulting in a high number of false positive results. We developed an HPLC method for BTD activity in serum with fluorescent detection. In colorimetric assays, biotinidase attacks the amide linkage of the artificial substrate biotinidyl-4-aminobenzoic acid (B-PABA) and releases p-aminobenzoic acid (PABA), which is converted to a purple dye by diazotization reaction. The newly developed method injects the reaction mixture directly into the HPLC column and quantifies using a six-point calibration curve without coupling and diazotization reaction. The method is linear over the 5-1000 μmol/L range. The detection and quantitation limits were 2.5 μmol/L and 5.0 μmol/L, respectively. When compared with colorimetric assay, the correlation coefficient (R2) was 0.9963. The within-assay and between-assay precision was <10.0% for four levels of quality control samples. No significant variation in BTD activity was detected due to hemolysis, icteric, and lipemic samples. The newly developed method eliminates the potential interference due to the presence of aromatic amines and significantly reduces the false positive results observed with the colorimetric method. It is simple, specific, sensitive, faster in sample preparation, and requires a small sample volume. The newly developed HPLC method was used in our laboratory as a secondary tier test for initial positive BTD samples from newborn screening programs. To our knowledge, no similar HPLC method has been reported to date.

HDAC-targeting epigenetic modulators for cancer immunotherapy

HDAC inhibitors, which can inhibit the activity of HDAC enzymes, have been extensively studied in tumor immunotherapy and have shown potential therapeutic effects in cancer immunotherapy. To date, numerous small molecule HDAC inhibitors have been identified, but many of them suffer from limited clinical efficacy and serious toxicity. Hence, HDAC inhibitor-based combination therapies, and other HDAC modulators (e.g. PROTAC degraders, dual-acting agents) have attracted great attention with significant advancements achieved in the past few years due to their superior efficacy compared to single-target HDAC inhibitors. In this review, we overviewed the recent progress on HDAC-based drug discovery with a focus on HDAC inhibitor-based drug combination therapy and other HDAC-targeting strategies (e.g. selective HDAC inhibitors, HDAC-based dual-target inhibitors, and PROTAC HDAC degraders) for cancer immunotherapy. In addition, we also summarized the reported co-crystal structures of HDAC inhibitors in complex with their target proteins and the binding interactions. Finally, the challenges and future directions for HDAC-based drug discovery in cancer immunotherapy are also discussed in detail.

Clinical Implications of Dietary Probiotic Supplement (Associated with L-Glutamine and Biotin) in Ulcerative Colitis Patients' Body Composition and Quality of Life

Patients with ulcerative colitis (UC) are reported to have changes in body structure, with negative impact on the course of disease. This study explored the effects of a standardized nutritional supplement containing five bacterial strains of at least five billion bacteria (Bifidobacterium infantis, Bifidobacterium animalis, Lactobacillus bulgaricus, Lactobacillus helveticus, and Enterococcus faecium), L-glutamine, and biotin on the body composition and quality of life of patients with UC. Ninety-three patients over 18 years of age with a confirmed diagnosis of UC, for whom body composition could be accurately determined, were included in this observational follow-up randomized study. These patients were split into two groups: UC-P (44 patients with dietary counselling and supplement with probiotics) and UC-NP (49 patients with dietary counselling, without supplement). Body composition was assessed using the multifrequency bioelectrical impedance device, and the quality of life related to UC was evaluated by applying the short inflammatory bowel disease questionnaire (SIBDQ). The results showed that the average value of muscular mass (MM) and sarcopenic index (SMI) significantly increased (p = 0.043, respectively, p = 0.001) and a large fraction (p = 0.001) of patients had their SMI levels normalized in the UC-P group compared with UC-NP group. The extracellular water to total body water ratio (ECW/TBW) also had significantly different mean values (p = 0.022), favoring the UC-P group. By testing the differences between the average values of body composition parameters before and after treatment, we obtained significant results in body mass index (BMI) (p = 0.046), fat free mass (FFM) (p < 0.001), and ECW/TBW ratio (p = 0.048). The SIBDQ total score increased significantly (p < 0.001) in the UC-P group and was more strongly associated with changes in body parameters. Supplementation with probiotics associated with L-glutamine and biotin can improve body composition parameters, which in turn implies an increase in the overall quality of life of patients with UC.

Biotin conjugates in targeted drug delivery: is it mediated by a biotin transporter, a yet to be identified receptor, or (an)other unknown mechanism(s)?

Conjugation of drugs with biotin is a widely studied strategy for targeted drug delivery. The structure-activity relationship (SAR) studies through H3-biotin competition experiments conclude with the presence of a free carboxylic acid being essential for its uptake via the sodium-dependent multivitamin transporter (SMVT, the major biotin transporter). However, biotin conjugation with a payload requires modification of the carboxylic acid to an amide or ester group. Then, there is the question as to how/whether the uptake of biotin conjugates goes through the SMVT. If not, then what is the mechanism? Herein, we present known uptake mechanisms of biotin and its applications reported in the literature. We also critically analyse possible uptake mechanism(s) of biotin conjugates to address the disconnect between the results from SMVT-based SAR and "biotin-facilitated" targeted drug delivery. We believe understanding the uptake mechanism of biotin conjugates is critical for their future applications and further development.

Novel SLC5A6 mutations lead to B lymphocyte maturation defects with metabolic abnormality rescuable by biotin replenishment

We characterized a family diagnosed with immunodeficiency disease presenting with low immunoglobulin levels and skin dyskeratosis. Exome sequencing revealed compound heterozygous missense variants in SLC5A6, the gene encoding a cellular sodium-dependent multivitamin transporter (SMVT) responsible for transporting vitamins, including biotin (vitamin B7). We showed that the biotin deficiency was caused by the SLC5A6 variants resulting in defective B cell differentiation and antibody deficiency. Altered cellular metabolic profiles, including aberrant mitochondrial respiration and reliance on glycolysis, may underlie the failure in plasma cell maturation. Replenishment of biotin improved plasma cell maturation and recovered the antibody producing activity in the patient and in a CRISPR-Cas9 gene-edited mouse model bearing a patient-specific SLC5A6 variant. Our results demonstrate the critical role of metabolic reprogramming in the maturation of plasma cells and nominate SLC5A6 as a causative gene for immunodeficiency that may be treated by biotin replenishment.

Elucidating the mechanisms underlying the anti-hyperlipidemic effects of Laportea bulbifera using integrated serum metabolomics and network pharmacology

Hyperlipidemia is a chronic metabolic disorder characterized by alterations in lipid metabolism as well as other pathways. Laportea bulbifera, an indigenous medicinal plant of Chinese herbal medicine, exhibits therapeutic effects on hyperlipidemia, but the mechanisms remain unclear. This study investigated the potential mechanisms underlying the anti-hyperlipidemic effects of L. bulbifera using an integrated strategy based on metabolomics and network pharmacology methods that were established to investigate the potential mechanism of anti-hyperlipidemia effect of L. bulbifera. First, the therapeutic effects of L. bulbifera on body weight reduction and biochemical indices were assessed. Next, 18 significant metabolites distinguishing the control and model groups were identified based on serum metabolomics and multivariate analyses. Then, a compound-target network was constructed by linking L. bulbifera and hyperlipidemia using network pharmacology. Three metabolic pathways involved in treating hyperlipidemia were identified. Finally, five crucial targets were selected by constructing a bionetwork starting from the compounds and ending in the metabolites. This study established an integrated strategy based on metabolomics coupled with network pharmacology and revealed the mechanism underlying the protective effects of L. bulbifera against hyperlipidemia for the first time.

Role of epigenetic modifications mediated by vitamins and trace elements in inflammatory bowel disease

Graphical abstract [Formula: see text] Numerous environmental factors frequently emerge as primary determinants of inflammatory bowel disease (IBD). Diet is a major component of environmental factors, and the consumption of vitamins (A, B, C and D) and trace elements (calcium, iron, zinc and selenium) exerts an impact on the progression of IBD through epigenetic modifications. Intake of vitamins A, B, C and D, as well as excessive amounts of iron and calcium, can modulate the condition of IBD by regulating the levels of DNA methylation, histone acetylation and miRNA. Zinc and selenium alleviate the progression of IBD by regulating the levels of promoter methylation or histone ubiquitination, respectively. Graphical Abstract was adapted from 'Epigenetic levels (layout)', by BioRender.com. Retrieved from https://app.biorender.com/biorender-templates.

A Bacillus subtilis Strain ZJ20 with AFB1 Detoxification Ability: A Comprehensive Analysis

As a class I carcinogen, aflatoxin can cause serious damage to various tissues and organs through oxidative stress injuries. The liver, as the target organ of AFB1, is the most seriously damaged. Biological methods are commonly used to degrade AFB1. In our study, the aflatoxin B1-degrading strain ZJ20 was screened from AFB1-contaminated feed and soil, and the degradation of AFB1 by ZJ20 was investigated. The whole genome of strain ZJ20 was analyzed, revealing the genomic complexity of strain ZJ20. The 16S rRNA analysis of strain ZJ20 showed 100% identity to Bacillus subtilis IAM 12118. Through whole gene functional annotation, it was determined that ZJ20 has high antioxidant activity and enzymatic activity; more than 100 CAZymes and 11 gene clusters are involved in the production of secondary metabolites with antimicrobial properties. In addition, B. subtilis ZJ20 was predicted to contain a cluster of genes encoding AFB1-degrading enzymes, including chitinase, laccase, lactonase, and manganese oxidase. The comprehensive analysis of B. subtilis provides a theoretical basis for the subsequent development of the biological functions of ZJ20 and the combinatorial enzyme degradation of AFB1.

Discovery of Novel d-(+)-Biotin-Conjugated Resorcinol Dibenzyl Ether-Based PD-L1 Inhibitors for Targeted Cancer Immunotherapy

In this work, we rationally designed, synthesized, and evaluated a series of novel d-(+)-biotin-conjugated PD-L1 inhibitors for targeted cancer therapy. Among them, SWS1 exhibited the highest anti-PD-1/PD-L1 activity with an IC50 of 1.8 nM. In addition, SWS1 dose-dependently promoted tumor cell death in a HepG2/Jurkat cell co-culture model. Importantly, SWS1 displayed high antitumor efficacy in a B16-F10 mouse model with tumor growth inhibition of 66.1%, which was better than that of P18 (44.3%). Furthermore, SWS1 exerted antitumor effects by increasing the number of tumor-infiltrating lymphocytes and reducing the expression of PD-L1 in tumor tissues. Moreover, tissue distribution studies revealed a substantial accumulation of SWS1 in tumors (404.1 ng/mL). Lastly, the safety profiles of SWS1 were better (e.g., less immune-mediated colitis) than those of P18, indicating the advantages of biotin-enabled tumor targeting capability. Taken together, our results suggest that these novel tumor-targeted PD-L1 inhibitors are worthy of further investigation as potential anticancer agents for targeted cancer immunotherapy.

Biotin Deficiency Induces Intestinal Dysbiosis Associated with an Inflammatory Bowel Disease-like Phenotype

Biotin is an essential vitamin and critical cofactor in several metabolic pathways, and its deficiency has been linked to several disorders including inflammatory bowel disease (IBD). We previously reported that biotin deficiency (BD) in mice, whether modeled through intestine-specific deletion of biotin transporter (SMVT-icKO) or through a biotin-deficient diet, resulted in intestinal inflammation consistent with an IBD-like phenotype. To assess whether the gut microbiome is associated with these BD-induced changes, we collected stool and intestinal samples from both of these mouse models and utilized them for 16S rRNA gene sequencing. We find that both diet-mediated and deletion-mediated BD result in the expansion of opportunistic microbes including Klebsiella, Enterobacter, and Helicobacter, at the expense of mucus-resident microbes including Akkermansia. Additionally, microbiome dysbiosis resulting from diet-mediated BD precedes the onset of the IBD-like phenotypic changes. Lastly, through the use of predictive metagenomics, we report that the resulting BD-linked microbiome perturbations exhibit increased biotin biosynthesis in addition to several other perturbed metabolic pathways. Altogether, these results demonstrate that biotin deficiency results in a specific microbiome composition, which may favor microbes capable of biotin synthesis and which may contribute to intestinal inflammation.

High Dose Pharmaceutical Grade Biotin (MD1003) Accelerates Differentiation of Murine and Grafted Human Oligodendrocyte Progenitor Cells In Vivo

Accumulating evidences suggest a strong correlation between metabolic changes and neurodegeneration in CNS demyelinating diseases such as multiple sclerosis (MS). Biotin, an essential cofactor for five carboxylases, is expressed by oligodendrocytes and involved in fatty acid synthesis and energy production. The metabolic effect of biotin or high-dose-biotin (MD1003) has been reported on rodent oligodendrocytes in vitro, and in neurodegenerative or demyelinating animal models. However, clinical studies, showed mild or no beneficial effect of MD1003 in amyotrophic lateral sclerosis (ALS) or MS. Here, we took advantage of a mouse model of myelin deficiency to study the effects of MD1003 on the behavior of murine and grafted human oligodendrocytes in vivo. We show that MD1003 increases the number and the differentiation potential of endogenous murine oligodendroglia over time. Moreover, the levels of MD1003 are increased in the plasma and brain of pups born to treated mothers, indicating that MD1003 can pass through the mother's milk. The histological analysis of the grafted animals shows that MD1003 increased proliferation and accelerates differentiation of human oligodendroglia, but without enhancing their myelination potential. These findings provide important insights into the role of MD1003 on murine and human oligodendrocyte maturation/myelination that may explain the mitigated outcome of ALS/MS clinical trials.

The effect of tuina on ulcerative colitis model mice analyzed by gut microbiota and proteomics

Tuina can effectively alleviate ulcerative colitis-related symptoms, but the mechanism of action is unknown. The purpose of this research is to explore potential pathways for the treatment of tuina through gut microbiota and proteomics techniques. Thirty-two male BALB/c mice were divided into four groups, the control, model, mesalazine, and tuina groups. The ulcerative colitis model was established by freely drinking a 3% dextran sulphate sodium solution for 7 days. The mesalazine group and the tuina group, respectively, received 7 days of mesalazine and tuina treatment. Subsequently, their body weights, feces properties, colon length, histomorphological changes, gut microbiota, and colon proteomics were determined. Body weights, disease activity index score, colon histological scores, and microbiota diversity were restored in the tuina group. At the phylum level, Firmicutes was increased and Bacteroidota decreased. At the family level, Lachnospiraceae increased and Prevotellaceae decreased. At the genus level, the Lachnospiraceae_NK4A136_group was increased. Proteomics detected 370 differentially expressed proteins regulated by tuina, enriched to a total of 304 pathways, including biotin metabolism, Notch signaling pathway, linoleic acid metabolism, and autophagy. Tuina can effectively improve the symptoms of weight loss, fecal properties, and colon inflammation in ulcerative colitis mice and restore the gut microbiota diversity, adjusting the relative abundance of microbiota. The therapeutic effects of tuina may be achieved by modulating the signaling pathways of biotin metabolism, Notch signaling pathway, linoleic acid metabolism, and autophagy.

Metagenomic study of the gut microbiota associated with cow milk consumption in Chinese peri-/postmenopausal women

Cow milk consumption (CMC) and alterations of gut bacterial composition are proposed to be closely related to human health and disease. Our research aims to investigate the changes in human gut microbial composition in Chinese peri-/postmenopausal women with different CMC habits. A total of 517 subjects were recruited and questionnaires about their CMC status were collected; 394 subjects were included in the final analyses. Fecal samples were used for studying gut bacterial composition. All the subjects were divided into a control group (n = 248) and a CMC group (n = 146) according to their CMC status. Non-parametric tests and LEfSe at different taxonomic levels were used to reveal differentially abundant taxa and functional categories across different CMC groups. Relative abundance (RA) of one phylum (p_Actinobacteria), three genera (g_Bifidobacterium, g_Anaerostipes, and g_Bacteroides), and 28 species diversified significantly across groups. Specifically, taxa g_Anaerostipes (p < 0.01), g_Bacteroides (p < 0.05), s_Anaerostipes_hadrus (p < 0.01), and s_Bifidobacterium_pseudocatenulatum (p < 0.01) were positively correlated with CMC levels, but p_Actinobacteria (p < 0.01) and g_Bifidobacterium (p < 0.01) were negatively associated with CMC levels. KEGG module analysis revealed 48 gut microbiome functional modules significantly (p < 0.05) associated with CMC, including Vibrio cholerae pathogenicity signature, cholera toxins (p = 9.52e-04), and cephamycin C biosynthesis module (p = 0.0057), among others. In conclusion, CMC was associated with changes in gut microbiome patterns including beta diversity and richness of some gut microbiota. The alterations of certain bacteria including g_Anaerostipes and s_Bifidobacterium_pseudocatenulatum in the CMC group should be important for human health. This study further supports the biological value of habitual cow milk consumption.

Changes in the Immunity, Histopathology, and Metabolism of Crayfish (Procambarus clarkii) in Response to Drought

Freshwater ecosystems are among the most threatened ecosystems on Earth. The freshwater biodiversity crisis has caused widespread global concern. Drought as one of the factors causing freshwater biodiversity is still poorly understood. Crayfish is often used in academic research as a biological indicator. In this study, flow cytometry, hematoxylin-eosin staining, and untargeted metabolomics were used to analyze the immune function, histopathology, and metabolism of crayfish under drought conditions. After drought exposure, the total hemocytes count (THC) was significantly decreased (from 8.9 × 105 mL−1 in the control group to 2.2 × 105 mL−1 at day 5). Phagocytosis decreased by 66% after 5 days of drought. The level of reactive oxygen species (ROS) in the hepatopancreas was upregulated. Moreover, histological disorder and metabolism changes in the hepatopancreas were obvious. These results indicate that drought suppresses immune function, disrupts the balance of oxidative and antioxidative systems, and induces tissue damage and metabolic changes in crayfish.

Antioxidant, anti-inflammatory and immunomodulatory roles of vitamins in COVID-19 therapy

oxidative stress is caused by an abundant generation of reactive oxygen species, associated to a diminished capacity of the endogenous systems of the organism to counteract them. Activation of pro-oxidative pathways and boosting of inflammatory cytokines are always encountered in viral infections, including SARS-CoV-2. So, the importance of counteracting cytokine storm in COVID-19 pathology is highly important, to hamper the immunogenic damage of the endothelium and alveolar membranes. Antioxidants prevent oxidative processes, by impeding radical species generation. It has been proved that vitamin intake lowers oxidative stress markers, alleviates cytokine storm and has a potential role in reducing disease severity, by lowering pro-inflammatory cytokines, hampering hyperinflammation and organ failure. For the approached compounds, direct antiviral roles are also discussed in this review, as these activities encompass secretion of antiviral peptides, modulation of angiotensin-converting enzyme 2 receptor expression and interaction with spike protein, inactivation of furin protease, or inhibition of pathogen replication by nucleic acid impairment induction. Vitamin administration results in beneficial effects. Nevertheless, timing, dosage and mutual influences of these micronutrients should be carefullly regarded.

Performance of a multi-compounds nutraceutical formulation in patients with symptomatic uncomplicated diverticular disease

BACKGROUND

Symptomatic uncomplicated diverticular disease (SUDD) is a recognized clinical condition characterized by abdominal pain and changes in bowel habits, attributed to diverticula but without macroscopic signs of diverticulitis. There is no consensus about the management of these patients. Enteroflegin®, an association of natural active ingredients, could be effective in the treatment of those patients.

METHODS

We conducted a retrospective observational study to evaluate the performances of Enteroflegin® in patients with SUDD. Patients were treated with Enteroflegin® 2 cp/day for 10 days per month for 6 months. Primary endpoint was the clinical remission rate, defined as the absence of any symptoms; secondary endpoints were the impact of the treatment on reduction of symptoms, on fecal calprotectin (FC) expression, and the prevention of acute diverticulitis.

RESULTS

Three hundred and fifty patients were retrospectively enrolled (183 males, median age 64 yrs, IQR 54-70). Enteroflegin® was effective in inducing remission in 9.34% and 17.64% of patients at 3 and 6 months respectively (p<0.001). Reduction of symptoms occurred in 92.3% and in 85.3% of patients at 3 and 6 months respectively (p<0.001), and symptoms' recurrence or worsening was recorded in only 1.71% of patients during the follow-up. FC expression dropped from 181,3 μg/g at baseline to 100,2 μg/g (p<0.001) and to 67,9 μg/g (p<0.001) at 3 and 6 months of follow-up respectively. No adverse event was recorded during the follow-up. Finally, acute diverticulitis occurred in just 2% of patients during the follow-up.

CONCLUSIONS

Enteroflegin® seems to be an effective nutraceutical compound in obtaining remission and symptom relief in SUDD patients. Further randomized, placebo-controlled clinical trials are needed to confirm these preliminary data.

Relevance of Biotin Deficiency in Patients with Inflammatory Bowel Disease and Utility of Serum 3 Hydroxyisovaleryl Carnitine as a Practical Everyday Marker

Background: Biotin, a water-soluble B vitamin, has demonstrable anti-inflammatory properties. A biotin-deficient diet induced a colitis-like phenotype in mice, alleviable by biotin substitution. Mice with dextran sulfate sodium (DSS)-induced colitis showed biotin deficiency and diminished levels of sodium-dependent multivitamin transporter, a protein involved in biotin absorption. Biotin substitution induced remission by reducing activation of NF-κB, a transcription factor involved in intestinal permeability and inflammatory bowel disease (IBD). We investigated for the first time a possible clinical role of biotin status in IBD. Methods: In a comparative, retrospective, cross-sectional study, serum samples of 138 patients with IBD (67 female; 72 Crohn’s disease (CD), 66 ulcerative colitis (UC)) aged 18–65 years and with a mean age (±SD) of 42.5 ± 14.3 years as well as 80 healthy blood donors (40 female; 40.0 ± 10.0 years; range 20–60 years) were analyzed. Inflammation was defined as hsCRP ≥5 mg/L, and to determine biotin status, serum 3-hydroxyisovaleryl carnitine (3HIVc) levels were measured by LC-MS/MS. Results: A total of 138 patients with IBD (67f; 72CD/66 UC; 42.5 ± 14.3 years) were enrolled: 83/138 had inflammation. Mean serum 3HIVc levels were significantly higher in IBD patients but unaffected by inflammation. Biotin deficiency (95th percentile of controls: >30 nmol/L 3HIVc) was significantly more common in IBD patients versus controls. Conclusion: High serum 3HIVc levels and biotin deficiency were associated with IBD but not inflammatory activity or disease type. Our findings suggest biotin may play a role as cause or effect in IBD pathogenesis. Routine assessment and supplementation of biotin may ameliorate IBD and support intestinal integrity.

Classroom microbiome, functional pathways and sick-building syndrome (SBS) in urban and rural schools - Potential roles of indoor microbial amino acids and vitamin metabolites

Sick building symptoms (SBS) are defined as non-specific symptoms related to indoor exposures, including mucosal symptoms in eye, nose, throat, and skin, and general symptoms as headache and tiredness. Indoor microbial composition is associated with SBS symptoms, but the impact of microbial functional genes and potential metabolic products has not been characterized. We conducted a shotgun microbial metagenomic sequencing for vacuum dust collected in urban and rural schools in Shanxi province, China. SBS symptoms in students were surveyed, and microbial taxa and functional pathways related to the symptoms were identified using a multi-level linear regression model. SBS symptoms were common in students, and the prevalence of ocular and throat symptoms, headache, and tiredness was higher in urban than in rural areas (p < 0.05). A significant higher microbial α-diversity was found in rural areas than in urban areas (Chao1, p = 0.001; ACE, p = 0.002). Also, significant variation in microbial taxonomic and functional composition (β-diversity) was observed between urban and rural areas (p < 0.005). Five potential risk Actinobacteria species were associated with SBS symptoms (p < 0.01); students in the classrooms with a higher abundance of an unclassified Geodermatophilaceae, Geodermatophilus, Fridmanniella luteola, Microlunatus phosphovorus and Mycetocola reported more nasal and throat symptoms and tiredness. Students with a higher abundance of an unclassified flavobacteriaceae reported fewer throat symptoms and tiredness. The abundance of microbial metabolic pathways related to the synthesis of B vitamins (biotin and folate), gamma-aminobutyric acid (GABA), short-chain fatty acids (SCFAs), and peptidoglycan and were protectively (negatively) associated with SBS symptoms (FDR < 0.05). The result is consistent with human microbiota studies, which reported that these microbial products are extensively involved in immunological processes and anti-inflammatory effects. This is the first study to report the functional potential of the indoor microbiome and the occurrence of SBS, providing new insights into the potential etiologic mechanisms in chronic inflammatory diseases.

Comparative analysis of the miRNA-mRNA regulation networks in turbot (Scophthalmus maximus L.) following Vibrio anguillarum infection

MicroRNAs could not only regulate posttranscriptional silencing of target genes in eukaryotic organisms, but also have positive effect on their target genes as well. These microRNAs have been reported to be involved in mucosal immune responses to pathogen infection in teleost. Therefore, we constructed the immune-related miRNA-mRNA networks in turbot intestine following Vibrio anguillarum infection. In our results, 1550 differentially expressed (DE) genes and 167 DE miRNAs were identified. 113 DE miRNAs targeting 89 DE mRNAs related to immune response were used to construct miRNA-mRNA interaction networks. Functional analysis showed that target genes were associated with synthesis and degradation of ketone bodies, mucin type O-Glycan biosynthesis, homologous recombination, biotin metabolism, and intestinal immune network for IgA production that were equivalent to the function of IgT and IgM in fish intestine. Finally, 10 DE miRNAs and 7 DE mRNAs were selected for validating the accuracy of high-throughput sequencing results by qRT-PCR. The results of this study will provide valuable information for the elucidation of the regulation mechanisms of miRNA-mRNA interactions involved in disease resistance in teleost mucosal immune system.

Atypical Brain MRI Findings in a Child With Delayed Diagnosis of Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) is the most common cause of autoimmune encephalitis in children with a wide spectrum of clinical presentation and MRI findings. A high index of suspicion is required to avoid a delay in treatment and long-term morbidity. We present a healthy two-year-old male who developed fever and viral prodrome symptoms that rapidly progressed to acute encephalopathy, status epilepticus, quadriparesis, and abnormal movements. Brain MRI showed symmetric involvement of bilateral insula, posterior part of basal ganglia, and thalami. The patient survived the acute phase with supportive therapy but ended up with a devastating neurologic sequela, including developmental delay, inability to communicate, dysphagia, quadriparesis, and cortical visual impairment. Anti-N-methyl-D-aspartate (anti-NMDA) immunoglobulin G (IgG) antibodies were negative in serum and cerebrospinal fluid (CSF). The patient underwent an extensive inflammatory, infectious, metabolic, and genetic workup, including a whole-exome sequence (WES) and mitochondrial panel, which was unremarkable. CSF studies were unremarkable. Repeated anti-NMDA IgG antibodies were positive in serum a year after the presentation. This presentation highlights the crucial role of early immunotherapy in suspected autoimmune encephalitis (AE) cases, even at a young age, to prevent devastating neurologic outcomes. Moreover, clinicians should not rely on antibody results to treat a suspected case of AE due to possible false-negative test results, and the majority of AE cases remain without known antibodies.

Association between Serum Biotin Levels and Cedar Pollinosis in Japanese Schoolchildren

Biotin is a water-soluble B complex vitamin and coenzyme of five types of carboxylase and plays crucial roles in fatty acid, glucose, and amino acid metabolism. Nutritional biotin deficiency and defective enzymes essential for biotin metabolism cause inflammatory diseases such as eczema-like dermatitis and Crohn's disease; however, little is known about the pathophysiological roles of biotin. This study investigated the relationship between biotin metabolism and human allergic sensitization and diseases by measuring serum levels of biotin, total immunoglobulin E (IgE) and allergen-specific IgEs in more than 400 Japanese schoolchildren aged 6 to 12. The prevalence of allergic diseases, and environmental and life-style factors were also examined by a questionnaire. Like total IgE, serum biotin levels of children showed a log-normal distribution. Meanwhile, Spearman's rank correlation analysis showed weak but significant positive associations between serum biotin levels and total IgE (rho=0.147, p=0.0029) as well as allergen-specific IgEs against egg whites (rho=0.215, p=0.00013), cedar pollen (rho=0.176, p=0.00036), and cat dander (rho=0.130, p=0.0085). Furthermore, mean serum biotin levels in children with cedar pollinosis, but not with other allergic diseases such as asthma and allergic rhinitis, were significantly higher than in those without (p=0.0015). These results suggest a correlation between serum biotin levels and the development of cedar pollinosis. Further prospective studies are needed to evaluate the causal relationship between biotin metabolism and cedar pollen sensitization and pollinosis development.

What We Know So Far about the Metabolite-Mediated Microbiota-Intestinal Immunity Dialogue and How to Hear the Sound of This Crosstalk

Trillions of microorganisms, termed the "microbiota", reside in the mammalian gastrointestinal tract, and collectively participate in regulating the host phenotype. It is now clear that the gut microbiota, metabolites, and intestinal immune function are correlated, and that alterations of the complex and dynamic host-microbiota interactions can have deep consequences for host health. However, the mechanisms by which the immune system regulates the microbiota and by which the microbiota shapes host immunity are still not fully understood. This article discusses the contribution of metabolites in the crosstalk between gut microbiota and immune cells. The identification of key metabolites having a causal effect on immune responses and of the mechanisms involved can contribute to a deeper insight into host-microorganism relationships. This will allow a better understanding of the correlation between dysbiosis, microbial-based dysmetabolism, and pathogenesis, thus creating opportunities to develop microbiota-based therapeutics to improve human health. In particular, we systematically review the role of soluble and membrane-bound microbial metabolites in modulating host immunity in the gut, and of immune cells-derived metabolites affecting the microbiota, while discussing evidence of the bidirectional impact of this crosstalk. Furthermore, we discuss the potential strategies to hear the sound of such metabolite-mediated crosstalk.

Biomedical Text Link Prediction for Drug Discovery: A Case Study with COVID-19

Link prediction in artificial intelligence is used to identify missing links or derive future relationships that can occur in complex networks. A link prediction model was developed using the complex heterogeneous biomedical knowledge graph, SemNet, to predict missing links in biomedical literature for drug discovery. A web application visualized knowledge graph embeddings and link prediction results using TransE, CompleX, and RotatE based methods. The link prediction model achieved up to 0.44 hits@10 on the entity prediction tasks. The recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as COVID-19, served as a case study to demonstrate the efficacy of link prediction modeling for drug discovery. The link prediction algorithm guided identification and ranking of repurposed drug candidates for SARS-CoV-2 primarily by text mining biomedical literature from previous coronaviruses, including SARS and middle east respiratory syndrome (MERS). Repurposed drugs included potential primary SARS-CoV-2 treatment, adjunctive therapies, or therapeutics to treat side effects. The link prediction accuracy for nodes ranked highly for SARS coronavirus was 0.875 as calculated by human in the loop validation on existing COVID-19 specific data sets. Drug classes predicted as highly ranked include anti-inflammatory, nucleoside analogs, protease inhibitors, antimalarials, envelope proteins, and glycoproteins. Examples of highly ranked predicted links to SARS-CoV-2: human leukocyte interferon, recombinant interferon-gamma, cyclosporine, antiviral therapy, zidovudine, chloroquine, vaccination, methotrexate, artemisinin, alkaloids, glycyrrhizic acid, quinine, flavonoids, amprenavir, suramin, complement system proteins, fluoroquinolones, bone marrow transplantation, albuterol, ciprofloxacin, quinolone antibacterial agents, and hydroxymethylglutaryl-CoA reductase inhibitors. Approximately 40% of identified drugs were not previously connected to SARS, such as edetic acid or biotin. In summary, link prediction can effectively suggest repurposed drugs for emergent diseases.

Effect of biotin supplementation on neuropathic pain induced by chronic constriction of the sciatic nerve in the rat

Background and purpose

Neuropathic pain is one of the most common types of chronic pain that is very difficult to treat. Numerous studies have shown the potential role of vitamins in relieving both hyperalgesia and allodynia. Based on the convincing evidence, this study was designed to evaluate the possible antinociceptive effect of biotin on neuropathic pain in rats.

Experimental approach

This study was performed on male Sprague Dawley rats weighing 200-300 g. Neuropathic pain was induced by tying the sciatic nerve. Chronic constriction injury (CCI) of the sciatic nerve resulted in hyperalgesia and allodynia. To measure the thermal hyperalgesia, the plantar test was used. Also to evaluate the cold and mechanical allodynia, acetone test and von Frey test were applied. Biotin (4, 8, and 16 mg/kg) was administered orally as two different treatment regimens, acute and chronic.

Findings/Results

Acute oral administration of biotin (4, 8, and 16 mg/kg p.o.) on the 7^th, 14^th, and 21^st postoperative days couldn't reduce pain sensitivity compared to the CCI group. However, following the oral administration of biotin (8 and 16 mg/kg p.o.) from the first day after the surgery until day 21, mechanical allodynia (P < 0.001) and heat hyperalgesia (P < 0.05) significantly relieved.

Conclusion and implications

Our results suggest that biotin can be considered as a potential therapeutic for the treatment of neuropathic pain, and supplementation with this vitamin could reduce the required doses of analgesic drugs. However, further studies are needed to confirm this hypothesis.

Nutritional Components in Western Diet Versus Mediterranean Diet at the Gut Microbiota-Immune System Interplay. Implications for Health and Disease

The most prevalent diseases of our time, non-communicable diseases (NCDs) (including obesity, type 2 diabetes, cardiovascular diseases and some types of cancer) are rising worldwide. All of them share the condition of an "inflammatory disorder", with impaired immune functions frequently caused or accompanied by alterations in gut microbiota. These multifactorial maladies also have in common malnutrition related to physiopathology. In this context, diet is the greatest modulator of immune system-microbiota crosstalk, and much interest, and new challenges, are arising in the area of precision nutrition as a way towards treatment and prevention. It is a fact that the westernized diet (WD) is partly responsible for the increased prevalence of NCDs, negatively affecting both gut microbiota and the immune system. Conversely, other nutritional approaches, such as Mediterranean diet (MD), positively influence immune system and gut microbiota, and is proposed not only as a potential tool in the clinical management of different disease conditions, but also for prevention and health promotion globally. Thus, the purpose of this review is to determine the regulatory role of nutritional components of WD and MD in the gut microbiota and immune system interplay, in order to understand, and create awareness of, the influence of diet over both key components.

Dietary supplements, vitamins and minerals as potential interventions against viruses: Perspectives for COVID-19

Abstract. The novel coronavirus (SARS-CoV-2) causing COVID-19 disease pandemic has infected millions of people and caused more than thousands of deaths in many countries across the world. The number of infected cases is increasing day by day. Unfortunately, we do not have a vaccine and specific treatment for it. Along with the protective measures, respiratory and/or circulatory supports and some antiviral and retroviral drugs have been used against SARS-CoV-2, but there are no more extensive studies proving their efficacy. In this study, the latest publications in the field have been reviewed, focusing on the modulatory effects on the immunity of some natural antiviral dietary supplements, vitamins and minerals. Findings suggest that several dietary supplements, including black seeds, garlic, ginger, cranberry, orange, omega-3 and -6 polyunsaturated fatty acids, vitamins (e.g., A, B vitamins, C, D, E), and minerals (e.g., Cu, Fe, Mg, Mn, Na, Se, Zn) have anti-viral effects. Many of them act against various species of respiratory viruses, including severe acute respiratory syndrome-related coronaviruses. Therefore, dietary supplements, including vitamins and minerals, probiotics as well as individual nutritional behaviour can be used as adjuvant therapy together with antiviral medicines in the management of COVID-19 disease.

B Vitamins and Their Role in Immune Regulation and Cancer

B group vitamins represent essential micronutrients for myriad metabolic and regulatory processes required for human health, serving as cofactors used by hundreds of enzymes that carry out essential functions such as energy metabolism, DNA and protein synthesis and other critical functions. B vitamins and their corresponding vitamers are universally essential for all cellular life forms, from bacteria to humans. Humans are unable to synthesize most B vitamins and are therefore dependent on their diet for these essential micronutrients. More recently, another source of B vitamins has been identified which is derived from portions of the 10¹³ bacterial cells inhabiting the gastrointestinal tract. Here we review the expanding literature examining the relationship between B vitamins and the immune system and diverse cancers. Evidence of B vitamin’s role in immune cell regulation has accumulated in recent years and may help to clarify the disparate findings of numerous studies attempting to link B vitamins to cancer development. Much work remains to be carried out to fully clarify these relationships as the complexity of B vitamins’ essential functions complicates an unequivocal assessment of their beneficial or detrimental effects in inflammation and cancers.

Micronutrients and bioactive compounds in the immunological pathways related to SARS-CoV-2 (adults and elderly)

The new coronavirus pandemic is affecting the entire world with more than 25 million confirmed cases in August 2020 according to the World Health Organization. It is known that the virus can affect several tissues and can progress to a respiratory failure in severe cases. To prevent the progression to this stage of the disease and minimize all the damage caused by coronavirus (SARS-CoV-2) the immune system must be in its integrity. A healthy nutritional status are fundamental to efficient immunological protection and consequently a good response to SARS-CoV-2. Micronutrients and bioactive compounds perform functions in immune cells that are extremely essential to stop SARS-CoV-2. Their adequate consumption is part of a non-pharmacological intervention to keep the immune system functioning. This review has as main objective to inform how micronutrients and bioactive compounds could act in the essential immunological pathways could stop SARS-CoV-2, focusing on the functions that have already established in the literature and transposing to this scenario.

Biotin Supplementation Ameliorates Murine Colitis by Preventing NF-κB Activation

BACKGROUND & AIMS

Biotin is a water-soluble vitamin that is indispensable for human health. Biotin deficiency can cause failure-to-thrive, immunodeficiency, alopecia, dermatitis, and conjunctivitis. We previously reported that biotin deficiency also can lead to severe colitis in mice, which is completely reversed with supplementation. Our aim in this study was to determine if high-dose biotin supplementation can provide a therapeutic benefit in a preclinical model for inflammatory bowel disease (IBD) and to identify the molecular mechanism by which this occurs.

METHODS

Mice were challenged with dextran sodium sulfate to induce colitis and were treated with 1 mmol/L biotin to induce or maintain remission. Clinical response was monitored by the Disease Activity Index and fecal calprotectin levels. The colon tissue was investigated for histology, length, as well as expression of inflammatory cytokines (interleukin 6, tumor necrosis factor-α, interleukin 1β), intestinal permeability, tight junctions (zonula occludens-1 and claudin-2), and the transcription factor nuclear factor-κB (NF-κB).

RESULTS

Biotin therapy led to delayed onset and severity of colitis as well as accelerated healing. There was improvement in the Disease Activity Index, fecal calprotectin levels, colon length, and histology. In addition, biotin-treated mice had reduced expression of inflammatory cytokines, reduced intestinal permeability, and reduced activation of NF-κB.

CONCLUSIONS

Oral supplementation with biotin provides benefit for maintenance and induction of remission in the dextran sodium sulfate preclinical model for IBD. Biotin does this by reducing the activation of NF-κB, which prevents the production of inflammatory cytokines and helps maintain the integrity of the intestinal barrier. Clinically, the NF-κB pathway is important in the development of IBD and this finding suggests that biotin may have therapeutic potential for patients with IBD.

Biotin: overview of the treatment of diseases of cutaneous appendages and of hyperseborrhea

One of the most common micronutrient deficiencies with cutaneous findings is the vitamin B, also known as biotin, deficiency. Biotin deficiency may be due to congenital lack of biotinidase, or acquired following some conditions that interfere with its absorption, such as inflammatory bowel disorders, a diet too rich in avidin, magnesium deficiency, smoking habit and treatment with broad-spectrum antibiotics, anticonvulsants and sulfonamides. This review highlights the role of biotin in the most common skin disorders such associated with biotin deficiency and an approach to their treatment. Biotin administration may improve the treatment of hair loss when deficiency is detected on the basis of a careful patient history, clinical examination and the determination of serum biotin levels. The use of biotin is rationale in seborrheic dermatitis as the vitamin intercepts the main metabolic pathways underlying the pathogenesis of the disease. Treatment with biotin could also be useful in comedonal acne characterized by a high rate of seborrhea, and may be helpful for acne treated with topical retinoids, contributing to the control of flaking and irritation. The tolerability of biotin is excellent and there is no risk of hypervitaminosis even in the case of high doses. It is important that administration is controlled by physicians and follows a medical diagnosis and prescription. Correct doses used in dermatological conditions are safe and are not at risk of interference with laboratory tests.

Tamoxifen-induced, intestinal-specific deletion of Slc5a6 in adult mice leads to spontaneous inflammation: involvement of NF-κB, NLRP3, and gut microbiota

The sodium-dependent multivitamin transporter (SMVT; SLC5A6) is involved in intestinal absorption of vitamin B7 (biotin). We have previously shown that mice with an embryonic intestinal-specific SMVT knockout (KO) develop biotin deficiency and severe spontaneous intestinal inflammation in addition to growth retardation, developmental delays, and death within the first 6-7 wk of life. The profound morbidity and mortality associated with the SMVT-KO has limited our ability to further characterize the intestinal inflammation and other sequelae of this deletion in adult mice with a mature gut microbiota. To overcome this limitation, we generated an intestine-specific, tamoxifen-inducible, conditional SMVT-KO (SMVT-icKO). Our results showed that adult SMVT-icKO mice have reduced body weight, biotin deficiency, shorter colonic length, and bloody diarrhea compared with age- and sex-matched control littermates. All SMVT-icKO mice also developed spontaneous intestinal inflammation associated with induction of calprotectin (S100a8/S100a9), proinflammatory cytokines (IL-1β, TNF-α, IFN-γ, and IL-6), and an increase in intestinal permeability. Additionally, the intestines of SMVT-icKO showed activation of the NF-κB pathway and the nucleotide-binding domain and leucine-rich repeat pyrin 3 domain (NLRP3) inflammasome. Notably, administration of broad-spectrum antibiotics reduced lethality and led to normalization of intestinal inflammation, proinflammatory cytokines, altered mucosal integrity, and reduced expression of the NLRP3 inflammasome. Overall, these findings support our conclusion that the biotin transport pathway plays an important role in the maintenance of intestinal homeostasis, and that NF-κB and the NLRP3 inflammasome, as well as gut microbiota, drive the development of intestinal inflammation when SMVT is absent.NEW & NOTEWORTHY This study demonstrates that deletion of the intestinal biotin uptake system in adult mice leads to the development of spontaneous gut inflammation and that luminal microbiota plays a role in its development.

Nutritional Modulation of Immune and Central Nervous System Homeostasis: The Role of Diet in Development of Neuroinflammation and Neurological Disease

The gut-microbiome-brain axis is now recognized as an essential part in the regulation of systemic metabolism and homeostasis. Accumulating evidence has demonstrated that dietary patterns can influence the development of metabolic alterations and inflammation through the effects of nutrients on a multitude of variables, including microbiome composition, release of microbial products, gastrointestinal signaling molecules, and neurotransmitters. These signaling molecules are, in turn, implicated in the regulation of the immune system, either promoting or inhibiting the production of pro-inflammatory cytokines and the expansion of specific leukocyte subpopulations, such as Th17 and Treg cells, which are relevant in the development of neuroinflammatory and neurodegenerative conditions. Metabolic diseases, like obesity and type 2 diabetes mellitus, are related to inadequate dietary patterns and promote variations in the aforementioned signaling pathways in patients with these conditions, which have been linked to alterations in neurological functions and mental health. Thus, maintenance of adequate dietary patterns should be an essential component of any strategy aiming to prevent neurological pathologies derived from systemic metabolic alterations. The present review summarizes current knowledge on the role of nutrition in the modulation of the immune system and its impact in the development of neuroinflammation and neurological disease.

Gastrointestinal Handling of Water-Soluble Vitamins

Nine compounds are classified as water-soluble vitamins, eight B vitamins and one vitamin C. The vitamins are mandatory for the function of numerous enzymes and lack of one or more of the vitamins may lead to severe medical conditions. All the vitamins are supplied by food in microgram to milligram quantities and in addition some of the vitamins are synthesized by the intestinal microbiota. In the gastrointestinal tract, the vitamins are liberated from binding proteins and for some of the vitamins modified prior to absorption. Due to their solubility in water, they all require specific carriers to be absorbed. Our current knowledge concerning each of the vitamins differs in depth and focus and is influenced by the prevalence of conditions and diseases related to lack of the individual vitamin. Because of that we have chosen to cover slightly different aspects for the individual vitamins. For each of the vitamins, we summarize the physiological role, the steps involved in the absorption, and the factors influencing the absorption. In addition, for some of the vitamins, the molecular base for absorption is described in details, while for others new aspects of relevance for human deficiency are included. © 2018 American Physiological Society. Compr Physiol 8:1291-1311, 2018.

Biotin and pantothenic acid oversupplementation to conditional SLC5A6 KO mice prevents the development of intestinal mucosal abnormalities and growth defects

Intestinal absorption of the water-soluble vitamins biotin and pantothenic acid is carrier mediated and involves the sodium-dependent multivitamin transporter (SMVT; product of the SLC5A6 gene). We recently observed that intestinal-specific (conditional) knockout of the mouse Slc5a6 gene (SMVT-cKO) is associated with growth retardation, the development of spontaneous and severe inflammation, abnormal histology in the large intestine, altered gut permeability, and early death. Our aim in this study was to examine the possibility that biotin and pantothenic acid oversupplementation (BPS) of the SMVT-cKO mice could reverse the above-described abnormalities. BPS was provided in the drinking water to mice before conception, to dams during pregnancy and lactation, and to the SMVT-cKO mice throughout their life. Our findings showed that such a regimen prevents early death, as well as normalizes the growth rate, intestinal integrity, pathology, and inflammation in SMVT-cKO mice. These findings provide clear evidence for a role for biotin and/or pantothenic acid in the maintenance of normal intestinal integrity and health.

Biotin Deficiency Induces Th1- and Th17-Mediated Proinflammatory Responses in Human CD4+ T Lymphocytes via Activation of the mTOR Signaling Pathway

Biotin (vitamin B7) is essential for human health because of its involvement, as a cofactor, in a variety of critical cellular metabolic reactions. Previous studies have shown that biotin deficiency enhances inflammation, and certain chronic inflammatory diseases are associated with biotin deficiency; however, the mechanisms that mediate the association between biotin status and inflammation are not well understood. In this study, we examined the effect of biotin deficiency on human CD4+ T cell responses to determine their role in biotin deficiency-associated inflammation. Our investigations revealed that anti-CD3/CD28-stimulated CD4+ T cells cultured in biotin-deficient medium secreted significantly enhanced levels of the proinflammatory cytokines IFN-γ, TNF, and IL-17. Expression of the transcription factors T-bet and RORγt was increased, whereas Foxp3 expression was decreased, in biotin-deficient CD4+ T cells. The percentage of T regulatory cells was also decreased under biotin-deficient condition. A similar increase in T-bet, RORγt, and proinflammatory cytokine levels, as well as a decrease in Foxp3, was observed in inguinal lymph nodes of mice fed a biotin-deficient diet relative to pair-fed controls. Furthermore, differentiation of CD4+ T cells toward Th1 and Th17 cells was also enhanced. In vitro and in vivo investigations indicated that the increased inflammatory response was due to enhanced activation of the mammalian target of rapamycin signaling pathway in biotin-deficient CD4+ T cells. In summary, these results demonstrate that biotin deficiency enhances the inflammatory responses in CD4+ T cells, which may contribute to inflammation associated with biotin deficiency.

Vitamins and Minerals in Inflammatory Bowel Disease

Indiscriminate use of multivitamin/mineral supplements in the general population may be misguided, but patients with chronic Inflammatory Bowel Diseases (IBD) should be monitored and compensated for nutritional deficiencies. Mechanistic links between vitamin/mineral deficiencies and IBD pathology has been found for some micronutrients and normalizing their levels is clinically beneficial. Others, like vitamin A, although instinctively desirable, produced disappointing results. Restoring normal levels of the selected micronutrients requires elevated doses to compensate for defects in absorptive or signaling mechanisms. This article describes some aspects of vitamin and mineral deficiencies in IBD, and summarizes pros and cons of supplementation.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Impact of Childhood Malnutrition on Host Defense and Infection

The global impact of childhood malnutrition is staggering. The synergism between malnutrition and infection contributes substantially to childhood morbidity and mortality. Anthropometric indicators of malnutrition are associated with the increased risk and severity of infections caused by many pathogens, including viruses, bacteria, protozoa, and helminths. Since childhood malnutrition commonly involves the inadequate intake of protein and calories, with superimposed micronutrient deficiencies, the causal factors involved in impaired host defense are usually not defined. This review focuses on literature related to impaired host defense and the risk of infection in primary childhood malnutrition. Particular attention is given to longitudinal and prospective cohort human studies and studies of experimental animal models that address causal, mechanistic relationships between malnutrition and host defense. Protein and micronutrient deficiencies impact the hematopoietic and lymphoid organs and compromise both innate and adaptive immune functions. Malnutrition-related changes in intestinal microbiota contribute to growth faltering and dysregulated inflammation and immune function. Although substantial progress has been made in understanding the malnutrition-infection synergism, critical gaps in our understanding remain. We highlight the need for mechanistic studies that can lead to targeted interventions to improve host defense and reduce the morbidity and mortality of infectious diseases in this vulnerable population.

Lipopolysaccharide inhibits colonic biotin uptake via interference with membrane expression of its transporter: a role for a casein kinase 2-mediated pathway

Biotin (vitamin B7), an essential micronutrient for normal cellular functions, is obtained from both dietary sources as well as gut microbiota. Absorption of biotin in both the small and large intestine is via a carrier-mediated process that involves the sodium-dependent multivitamin transporter (SMVT). Although different physiological and molecular aspects of intestinal biotin uptake have been delineated, nothing is known about the effect of LPS on the process. We addressed this issue using in vitro (human colonic epithelial NCM460 cells) and in vivo (mice) models of LPS exposure. Treating NCM460 cells with LPS was found to lead to a significant inhibition in carrier-mediated biotin uptake. Similarly, administration of LPS to mice led to a significant inhibition in biotin uptake by native colonic tissue. Although no changes in total cellular SMVT protein and mRNA levels were observed, LPS caused a decrease in the fraction of SMVT expressed at the cell surface. A role for casein kinase 2 (CK2) (whose activity was also inhibited by LPS) in mediating the endotoxin effects on biotin uptake and on membrane expression of SMVT was suggested by findings that specific inhibitors of CK2, as well as mutating the putative CK2 phosphorylation site (Thr⁷⁸Ala) in the SMVT protein, led to inhibition in biotin uptake and membrane expression of SMVT. This study shows for the first time that LPS inhibits colonic biotin uptake via decreasing membrane expression of its transporter and that these effects likely involve a CK2-mediated pathway.

Mutations in SLC5A6 associated with brain, immune, bone, and intestinal dysfunction in a young child

The human sodium-dependent multivitamin transporter (hSMVT) is a product of the SLC5A6 gene and mediates biotin, pantothenic acid, and lipoate uptake in a variety of cellular systems. We report here the identification of mutations R94X, a premature termination, and R123L, a dysfunctional amino acid change, both in exon 3 of the SLC5A6 gene in a child using whole genome-scanning. At 15 months of age, the child showed failure to thrive, microcephaly and brain changes on MRI, cerebral palsy and developmental delay, variable immunodeficiency, and severe gastro-esophageal reflux requiring a gastrostomy tube/fundoplication, osteoporosis, and pathologic bone fractures. After identification of the SLC5A6 mutations, he responded clinically to supplemental administration of excess biotin, pantothenic acid, and lipoate with improvement in clinical findings. Functionality of the two mutants was examined by ³H-biotin uptake assay following expression of the mutants in human-derived intestinal HuTu-80 and brain U87 cells. The results showed severe impairment in biotin uptake in cells expressing the mutants compared to those expressing wild-type hSMVT. Live cell confocal imaging of cells expressing the mutants showed the R94X mutant to be poorly tolerated and localized in the cytoplasm, while the R123L mutant was predominantly retained in the endoplasmic reticulum. This is the first reporting of mutations in the SLC5A6 gene in man, and suggests that this gene is important for brain development and a wide variety of clinical functions.

Role of the sodium-dependent multivitamin transporter (SMVT) in the maintenance of intestinal mucosal integrity

Utilizing a conditional (intestinal-specific) knockout (cKO) mouse model, we have recently shown that the sodium-dependent multivitamin transporter (SMVT) (SLC5A6) is the only biotin uptake system that operates in the gut and that its deletion leads to biotin deficiency. Unexpectedly, we also observed that all SMVT-cKO mice develop chronic active inflammation, especially in the cecum. Our aim here was to examine the role of SMVT in the maintenance of intestinal mucosal integrity [permeability and expression of tight junction (TJ) proteins]. Our results showed that knocking out the mouse intestinal SMVT is associated with a significant increase in gut permeability and with changes in the level of expression of TJ proteins. To determine whether these changes are related to the state of biotin deficiency that develops in SMVT-cKO mice, we induced (by dietary means) biotin deficiency in wild-type mice and examined its effect on the above-mentioned parameters. The results showed that dietary-induced biotin deficiency leads to a similar development of chronic active inflammation in the cecum with an increase in the level of expression of proinflammatory cytokines, as well as an increase in intestinal permeability and changes in the level of expression of TJ proteins. We also examined the effect of chronic biotin deficiency on permeability and expression of TJ proteins in confluent intestinal epithelial Caco-2 monolayers but observed no changes in these parameters. These results show that the intestinal SMVT plays an important role in the maintenance of normal mucosal integrity, most likely via its role in providing biotin to different cells of the gut mucosa.

Biotin deficiency enhances the inflammatory response of human dendritic cells

The water-soluble biotin (vitamin B7) is indispensable for normal human health. The vitamin acts as a cofactor for five carboxylases that are critical for fatty acid, glucose, and amino acid metabolism. Biotin deficiency is associated with various diseases, and mice deficient in this vitamin display enhanced inflammation. Previous studies have shown that biotin affects the functions of adaptive immune T and NK cells, but its effect(s) on innate immune cells is not known. Because of that and because vitamins such as vitamins A and D have a profound effect on dendritic cell (DC) function, we investigated the effect of biotin levels on the functions of human monocyte-derived DCs. Culture of DCs in a biotin-deficient medium (BDM) and subsequent activation with LPS resulted in enhanced secretion of the proinflammatory cytokines TNF-α, IL-12p40, IL-23, and IL-1β compared with LPS-activated DCs cultured in biotin-sufficient (control) and biotin-oversupplemented media. Furthermore, LPS-activated DCs cultured in BDM displayed a significantly higher induction of IFN-γ and IL-17 indicating Th1/Th17 bias in T cells compared with cells maintained in biotin control or biotin-oversupplemented media. Investigations into the mechanisms suggested that impaired activation of AMP kinase in DCs cultured in BDM may be responsible for the observed increase in inflammatory responses. In summary, these results demonstrate for the first time that biotin deficiency enhances the inflammatory responses of DCs. This may therefore be one of the mechanism(s) that mediates the observed inflammation that occurs in biotin deficiency.