Fucoidan enhances the anti-tumor effect of anti-PD-1 immunotherapy by regulating gut microbiota.

Currently, the clinical efficacy of anti-PD-1/PD-L1 monotherapy strategies against breast cancer is limited, and low response rates need to be improved. Gut microbiota plays a crucial role in the sensitization process of immunotherapy. As a natural dietary supplement, fucoidan has been reported to have immunomodulatory effects, while some studies have found that oral fucoidan may act as a potential prebiotic to modulate the gut microbiota. Therefore, this study investigated whether fucoidan could enhance the effects of anti-PD-1 monoclonal antibody antitumor immunotherapy by modulating gut microbiota and its metabolites. We found that the anti-tumor effect of the combination treatment was significantly enhanced, while fucoidan significantly improved the composition of the gut microbiota by increasing the number of potentially beneficial bacteria, such as Bifidobacterium, Faecalibaculum and Lactobacillus. Interference with the gut microbiota by antibiotics revealed impaired antitumor efficacy, confirming the necessity of gut microbiota in the antitumor effects of fucoidan in vivo. Metabolomics further revealed that fucoidan may have reversed the metabolic disturbances induced by the breast cancer model through tryptophan metabolism and glycerophospholipid metabolism pathways, with the most significant increase in the content of short-chain fatty acids, especially acetic and butyric acids. These modulations improved the function of effector T cells and suppressed Treg cell production. Thus, our findings suggest that fucoidan combined with the anti-PD-1 monoclonal antibody may be a novel strategy to sensitize breast cancer patients to anti-PD-1 monoclonal antibody immunotherapy. Meanwhile, the gut microbiota might serve as a new biomarker to predict the anti-PD-1 monoclonal antibody response to breast cancer immunotherapy.

The preventive effects of inulin, cellulose, and their mixture on colorectal cancer liver metastasis in mice by regulating gut microbiota.

Many studies have found that dietary fiber can protect against colorectal cancer (CRC). Survival in CRC patients is significantly reduced due to metastasis. However, little is known regarding the impact of dietary fiber on the CRC metastasis. In this study, we analyzed the effects of inulin, cellulose, and their mixture on CRC metastasis in a murine orthotopic transplantation model. BALB/C male mice were divided into the normal control (NC) (AIN-93 M diet), MOD (AIN-93 M diet), INU (10% w/w inulin), CEL (10% w/w cellulose), and MIX (5% w/w inulin + 5% w/w cellulose) groups. Dietary fiber intake inhibited the weights of the orthotopic tumors, liver weights, and liver metastasis area (p < 0.05) and improved the survival rate of tumor-bearing mice. Compared to the NC, the expression of ß-catenin and the epithelial marker E-cadherin were lower, and that of mesenchymal markers, such as N-cadherin, MMP-9, and VEGF, were higher in the MOD group. All inulin, cellulose, and their mixture restored the gut microbiota diversity, and they, respectively, increased the relative abundance of Bifidobacteriales, Lactobacillus, and Lachnospiraceae. Inulin restored the levels of acetic acid, propionic acid, isobutyric acid, and butyric acid. Spearman correlation analysis results showed that there was a positive correlation between five genera and six short-chain fatty acids (SCFAs) (adjusted p < 0.05). In conclusion, all inulin, cellulose, and their mixture have inhibitory effects on CRC metastasis, which may be achieved by the regulation of gut microbiota, the production of SCFAs, and the inhibition of the epithelial-to-mesenchymal transition process. Among the three dietary fiber intervention groups, the inhibitory effect of inulin is more significant.

Folic Acid Protects against Ethanol-Induced Hepatic Mitophagy Imbalance by ROS Scavenging and Attenuating the Elevated Hcy Levels.

Ample evidence indicates that ethanol-induced oxidative stress and mitochondrial dysfunction are central to the pathogenesis of alcoholic liver disease (ALD). As an adaptive quality control mechanism, mitophagy removes dysfunctional mitochondria to avert hepatic lesions in ALD. Folic acid exhibits potential radical scavenging properties and has been proven to ameliorate mitochondrial disorder in oxidative stress-related diseases. In this study, we aimed to uncover the mitophagy regulatory effects of folic acid in a 10w alcohol C57BL/6J mice feeding model (56% v/v) and L02 cells model cultured with ethanol (2.5% v/v). The results showed that folic acid alleviates ethanol-induced liver injury, decreasing oxidative stress and restoring liver enzyme. Furthermore, folic acid improved the mitochondrial function and inhibited ethanol-activated mitophagy through decreasing PINK1-Parkin and Drp1 expression, which inhibited the release of mitochondrial cytochrome C to the cytoplasm, preventing hepatocyte apoptosis. Intriguingly, folic acid attenuates the elevated hepatic homocysteine (Hcy) level. Additionally, the pretreatment of L02 cells with folic acid also ameliorated Hcy-induced oxidative damage, mitochondrial fission, and mitophagy. In summary, these results suggest that folic acid has beneficial effects in mitophagy remodeling by ROS scavenging and facilitating Hcy metabolism and could be developed as a potential therapeutic agent against ALD.

Tributyrin alleviates gut microbiota dysbiosis to repair intestinal damage in antibiotic-treated mice.

Tributyrin (TB) is a butyric acid precursor and has a key role in anti-inflammatory and intestinal barrier repair effects by slowly releasing butyric acid. However, its roles in gut microbiota disorder caused by antibiotics remain unclear. Herein, we established an intestinal microbiota disorder model using ceftriaxone sodium via gavage to investigate the effects of different TB doses for restoring gut microbiota and intestinal injury. First, we divided C57BL/6 male mice into two groups: control (NC, n = 8) and experimental (ABx, n = 24) groups, receiving gavage with 0.2 mL normal saline and 400 mg/mL ceftriaxone sodium solution for 7 d (twice a day and the intermediate interval was 6 h), respectively. Then, mice in the ABx group were randomly split into three groups: model (M, 0.2 mL normal saline), low TB group (TL, 0.3 g/kg BW), and high TB group (TH, 3 g/kg BW) for 11 d. We found that TB supplementation alleviated antibiotics-induced weight loss, diarrhea, and intestinal tissue damage. The 16S rRNA sequence analysis showed that TB intervention increased the α diversity of intestinal flora, increased potential short-chain fatty acids (SCFAs)-producing bacteria (such as Muribaculaceae and Bifidobacterium), and inhibited the relative abundance of potentially pathogenic bacteria (such as Bacteroidetes and Enterococcus) compared to the M group. TB supplementation reversed the reduction in SCFAs production in antibiotic-treated mice. Additionally, TB downregulated the levels of serum LPS and zonulin, TNF-α, IL-6, IL-1ß and NLRP3 inflammasome-related factors in intestinal tissue and upregulated tight junction proteins (such as ZO-1 and Occludin) and MUC2. Overall, the adjustment ability of low-dose TB to the above indexes was stronger than high-dose TB. In conclusion, TB can restore the dysbiosis of gut microbiota, increase SCFAs, suppress inflammation, and ameliorate antibiotic-induced intestinal damage, indicating that TB might be a potential gut microbiota modulator.

The Combination of Inositol Hexaphosphate and Inositol Inhibits Metastasis of Colorectal Cancer Cells by Upregulating Claudin 7.

Inositol hexaphosphate (IP6), a widely found natural bioactive substance in grains, effectively inhibits the progression of colorectal cancer (CRC) when used in combination with inositol (INS). We previously showed that supplementation of IP6 and INS upregulated the claudin 7 gene in orthotropic CRC xenografts in mice. The aim of this study was to elucidate the role of claudin 7 in the inhibition of CRC metastasis by IP6 and INS, and explore the underlying mechanisms. We found that IP6, INS and their combination inhibited the epithelial-mesenchymal transition (EMT) of colon cancer cell lines (SW480 and SW620), as indicated by upregulation of claudin 7 and E-cadherin, and downregulation of N-cadherin. The effect of IP6 and INS was stronger compared to either agent alone (combination index < 1). Furthermore, the silencing of the claudin 7 gene diminished the anti-metastatic effects of IP6 and INS on SW480 and SW620 cells. Consistent with in vitro findings, the combination of IP6 and INS suppressed CRC xenograft growth in a mouse model, which was neutralized by claudin 7. Taken together, the combination of IP6 and INS can inhibit CRC metastasis by blocking EMT of tumor cells through upregulation of claudin 7.

IP6 reduces colorectal cancer metastasis by mediating the interaction of gut microbiota with host genes.

Inositol hexaphosphate (IP6) is a phytochemical widely found in grains and legumes that plays an anti-cancer role. However, the mechanism underlying the inhibition of colorectal cancer metastasis by IP6 through host genes, gut microbiota, and their interactions remain elusive. In this study, 16S rRNA sequencing was used to study the effect of IP6 on gut microbiota in an orthotopic transplantation model of colorectal cancer mice. The transcriptome was used to study the changes of host genes in metastasis and the relationship with gut microbiota. The results showed that the gut microbiota composition of model mice was significantly different from that of normal mice. The beta diversity partly tended to return to the normal level after IP6 intervention. Especially, Lactobacillus helveticus and Lactococcus lactis were recovered after IP6-treated. Enrichment analysis showed that the enrichment score of the Cytokine-Cytokine receptor interaction signal pathway decreased after IP6 treatment compared to the model group. Further analysis of differentially expressed genes (DEGs) in this pathway showed that IP6 reduced the expression of the Tnfrsf1b gene related to the area of liver metastasis, and the Tnfrsf1b gene was negatively correlated with the relative abundance of Lactobacillus helveticus. Our results presented that host gene, microbiome and their interaction may serve as promising targets for the mechanism of IP6 intervention in colorectal cancer metastasis.

Folic acid intervention changes liver Foxp3 methylation and ameliorates the damage caused by Th17/Treg imbalance after long-term alcohol exposure.

Folic acid, as a key source of methyl donor in DNA methylation, has been proved to play a beneficial role in inflammation modulation, which is usually impaired in alcoholic liver disease (ALD). However, the role of folic acid in alcoholic liver inflammation and injury remain elusive. In this study, we sought to uncover the potential protective mechanism by which folic acid ameliorates alcoholic liver injury. 100 male C57BL/6J mice were randomly divided into 5 groups: normal saline group, folic acid control group (5 mg per kg BW), ethanol model group (56% v/v, 10 mL per kg BW), folic acid + ethanol group, and 5-Aza + ethanol group (0.1 mL per 20 g BW). Liquor (10 mL per kg BW) was orally administered 1 h after the folic acid treatment for 10 consecutive weeks. The results showed that folic acid-inhibited ethanol-induced serum TG, TC, and LDL elevation attenuated hepatic fat accumulation and maintained ALT at a normal level. 10 weeks of ethanol administration simultaneously upregulated the hepatic proportion of Th17 and Treg cells to different extents and broke the homeostasis of liver immunization. Folic acid limited ethanol-induced inflammatory injury by increasing the frequency of hepatic Treg cells. Importantly, this effect may be caused by decreased DNMT3a, which in turn downregulates the methylated levels of CPG2 and CPG3 in the Foxp3 promoter region, changing the abundance of Foxp3 expression and improving the Th17/Treg imbalance. In summary, our findings demonstrated that folic acid supplementation may relieve ethanol-induced Th17/Treg disbalance through altering Foxp3 promoter methylation patterns, suggesting that folic acid may be a feasible preventive strategy for ALD.

Considering Genetic Heterogeneity in the Association Analysis Finds Genes Associated With Nicotine Dependence.

While substantial progress has been made in finding genetic variants associated with nicotine dependence (ND), a large proportion of the genetic variants remain undiscovered. The current research focuses have shifted toward uncovering rare variants, gene-gene/gene-environment interactions, and structural variations predisposing to ND, the impact of genetic heterogeneity in ND has been nevertheless paid less attention. The study of genetic heterogeneity in ND not only could enhance the power of detecting genetic variants with heterogeneous effects in the population but also improve our understanding of genetic etiology of ND. As an initial step to understand genetic heterogeneity in ND, we applied a newly developed heterogeneity weighted U (HWU) method to 26 ND-related genes, investigating heterogeneous effects of these 26 genes in ND. We found no strong evidence of genetic heterogeneity in genes such as CHRNA5. However, results from our analysis suggest heterogeneous effects of CHRNA6 and CHRNB3 on nicotine dependence in males and females. Following the gene-based analysis, we further conduct a joint association analysis of two gene clusters, CHRNA5-CHRNA3-CHRNB4 and CHRNB3-CHRNA6. While both CHRNA5-CHRNA3-CHRNB4 and CHRNB3-CHRNA6 clusters are significantly associated with ND, there is a much stronger association of CHRNB3-CHRNA6 with ND when considering heterogeneous effects in gender (p-value = 2.11E-07).

Statistical Methods and Software for Substance Use and Dependence Genetic Research.

BACKGROUND: Substantial substance use disorders and related health conditions emerged dur-ing the mid-20th century and continue to represent a remarkable 21st century global burden of disease. This burden is largely driven by the substance-dependence process, which is a complex process and is influenced by both genetic and environmental factors. During the past few decades, a great deal of pro-gress has been made in identifying genetic variants associated with Substance Use and Dependence (SUD) through linkage, candidate gene association, genome-wide association and sequencing studies. METHODS: Various statistical methods and software have been employed in different types of SUD ge-netic studies, facilitating the identification of new SUD-related variants. CONCLUSION: In this article, we review statistical methods and software that are currently available for SUD genetic studies, and discuss their strengths and limitations.