A widespread single amino acid mutation in AcrA reduces tigecycline susceptibility in Klebsiella pneumoniae.

IMPORTANCE: Tigecycline, a glycecycline antibiotic with broad-spectrum activity against almost all Gram-positive and Gram-negative bacteria, is a highly concerned "last-resort" antibiotic. In addition to plasmid-hosted mobile tet(X) conferring high-level resistance to tigecycline, there are many reports suggesting increased expression of AcrAB-TolC efflux pump leads to tigecycline non-susceptibility. However, the role of mutations in AcrAB-TolC on tigecycline resistance has not been identified. This study reports a novel T188A mutation of the AcrA subunit of AcrAB-TolC complex in a clinical tigecycline-resistant Klebsiella pneumoniae strain and reveals the role of AcrA mutation on tigecycline resistance in K. pneumoniae. High prevalence of A188 type AcrA in hypervirulent multidrug-resistant K. pneumoniae indicates that mutations of the AcrAB-TolC complex may play a larger role in determining bacterial pathogenesis and antibiotic susceptibility than previously expected.

A novel Fc-enhanced humanized monoclonal antibody targeting B7-H3 suppresses the growth of ESCC.

Esophageal squamous cell carcinoma (ESCC) is a prevalent malignant tumor of the digestive tract with a low 5-year survival rate due to the lack of effective treatment methods. Although therapeutic monoclonal antibodies (mAbs) now play an important role in cancer therapy, effective targeted mAbs are still lacking for ESCC. B7-H3 is highly expressed in a variety of tumors and has emerged as a promising therapeutic target. Several mAbs against B7-H3 have advanced to clinical trials, but their development has not yet been pursued for ESCC. Here, we developed a humanized and Fc-engineered anti-B7H3 mAb 24F-Hu-mut2 and systematically evaluated its anti-tumor activity in vitro and in vivo. The 24F-Hu-mut2 was humanized and modified in Fc fragment to obtain stronger antibody-dependent cell-mediated cytotoxicity(ADCC) activity and nanomolar affinity. Furthermore, both of ESCC cell-derived xenograft (CDX) and patient-derived xenograft (PDX) mice models indicated that 24F-Hu-mut2 displayed potent in vivo anti-tumor activity. In addition, a computational docking model showed that the mAb bound to IgC1 and IgC2 domain of B7-H3, which is closer to the cell membrane. Consistently, our ELISA results verified the binding of 24F-Hu-WT and IgC1 and IgC2. Our results indicate that 24F-Hu-mut2 has significant anti-ESCC activity both in vitro and in vivo, and this monoclonal antibody may be a promising antibody against ESCC and other B7-H3 overexpressing tumors.

Apoptosis inhibition enhances induced pluripotent stem cell generation during T cell reprogramming.

The widespread adoption of chimeric antigen receptor (CAR)-T cell therapy has been hindered by its complex and costly manufacturing process. Induced pluripotent stem cells (iPSCs) have shown promise as a cellular immunotherapy alternative, due to their unlimited self-renewal potential in culture and capacity to differentiate into functional immune cell types. However, it is imperative to carefully select the original cell for iPSC seed preparation, as iPSCs have been found to retain the epigenetic imprint of the original somatic cells. Additionally, the efficiency of reprogramming terminal differentiated cells for immunotherapy must be addressed. Our research highlights the superiority of lymphocyte-origin cells over embryonic stem cells in functional immune cell differentiation. Furthermore, blocking Fas-FasL induced apoptosis in T cells significantly improves iPSC generation. Interestingly, transient Fas suppression in T cells does not alter the expression of Fas in the resulting iPSCs or affect their differentiation potential. This finding brings up new avenues in the field of cellular immunotherapy and provides a solution for creating high-quality and suitable iPSCs for lymphocyte differentiation for immunotherapy purposes.

Exposure to Fluoride From in Utero to Puberty Alters Gonadal Structure and Steroid Hormone Expression in Offspring Rats.

The reproductive toxicity of fluoride has been proven by a large number of studies. While the underlying mechanism of reproductive toxicity during pregnancy is still unclear. Hence, in this study, we investigated the effects of fluoride exposure on ovarian and testicular steroid hormone synthesis in young and adult rat offspring. We established a model of fluoride-exposed rat pups from in utero to puberty to explore the mechanisms of fluoride impacts on reproductive toxicity in the offspring. The results showed that NaF exposure did not affect the 3 weeks of age offspring. Whereas the body weight in both sexes significantly decreased, and the ovarian and testicular tissue structures were damaged at 11 weeks of age. In females, the total number of secondary follicles and mature follicles were significantly reduced after NaF exposure. Moreover, estradiol (E2) and follicle-stimulating hormone (FSH) levels in the females were significantly reduced in the 100 mg/L NaF exposure group. In males, the sperm viability and testosterone (T) were significantly decreased in the NaF exposure groups. Additionally, during steroidogenesis in ovaries and testes, fluoride remarkably decreased the expression levels of genes and proteins, including acute regulatory protein (StAR), 3ß-hydroxysteroid dehydrogenase (3ß-HSD), cytochrome P450 17a-hydroxylase (CYP17A1), and cholesterol side-chain cleavage enzyme (CYP11A1), while the mRNA levels of 17ß-hydroxysteroid dehydrogenase (17ß-HSD) decreased only in the testes. These results indicated that fluoride exposure disrupted the steroid hormone balance by changing several important steroidogenic-related genes associated with the development of the gonads, and damage the normal structure of the gonads in rat offspring.

Characterization of age-related immune features after autologous NK cell infusion: Protocol for an open-label and randomized controlled trial.

Background: Aging is usually accompanied by functional declines of the immune system, especially in T-cell responses. However, little is known about ways to alleviate this. Methods: Here, 37 middle-aged healthy participants were recruited, among which 32 were intravenously administrated with expanded NK cells and 5 with normal saline. Then, we monitored changes of peripheral senescent and exhausted T cells within 4 weeks after infusion by flow cytometry, as well as serum levels of senescence-associated secretory phenotype (SASP)-related factors. In vitro co-culture assays were performed to study NK-mediated cytotoxic activity against senescent or exhausted T cells. Functional and phenotypic alteration of NK cells before and after expansion was finally characterized. Results: After NK cell infusion, senescent CD28-, CD57+, CD28-CD57+, and CD28-KLRG1+ CD4+ and CD8+ T-cell populations decreased significantly, so did PD-1+ and TIM-3+ T cells. These changes were continuously observed for 4 weeks. Nevertheless, no significant changes were observed in the normal saline group. Moreover, SASP-related factors including IL-6, IL-8, IL-1α, IL-17, MIP-1α, MIP-1ß, and MMP1 were significantly decreased after NK cell infusion. Further co-culture assays showed that expanded NK cells specifically and dramatically eliminated senescent CD4+ T cells other than CD28+CD4+ T cells. They also showed improved cytotoxic activity, with different expression patterns of activating and inhibitory receptors including NKG2C, NKG2A, KLRG1, LAG3, CD57, and TIM3. Conclusion: Our findings imply that T-cell senescence and exhaustion is a reversible process in healthy individuals, and autologous NK cell administration can be introduced to alleviate the aging. Clinical Trial Registration: ClinicalTrials.gov, ChiCTR-OOh-17011878.

Clinical application of oscillometry in respiratory diseases: an impulse oscillometry registry.

Background: Respiratory oscillometry is a promising complement to the traditional pulmonary function tests for its simplicity. The usefulness of oscillometry in adult clinical practice has not been clarified. This study aimed to analyse the characteristics and diagnostic performance of oscillometry in respiratory diseases, and explore the cut-offs of oscillometric parameters for severity grading. Methods: In this multicentre registry of impulse oscillometry (IOS), IOS and spirometric data of healthy individuals and patients with respiratory diseases were collected and analysed. Linear mixed model analysis was performed to explore the effects of disease and forced expiratory volume in 1 s (FEV1) on oscillometric parameters. Results: The study included 567 healthy subjects, 781 asthmatic patients, 688 patients with chronic obstructive pulmonary disease (COPD), 109 patients with bronchiectasis, 40 patients with upper airway obstruction (UAO) and 274 patients with interstitial lung disease (ILD) in the analysis. Compared at the same FEV1 level, asthma, COPD, bronchiectasis, UAO and ILD displayed different oscillometric characteristics. The z-score of resistance at 5 Hz (R 5) was the best variable to identify respiratory diseases with a sensitivity of 62.4-66.7% and a specificity of 81.5-90.3%. With reference to the severity grading cut-offs of FEV1, R 5 z-scores of 2.5 and 4 were defined as the cut-off values of moderately and severely increased R 5. Conclusion: Respiratory oscillometry is more appropriate to be a tool of evaluating, rather than of diagnosing, respiratory diseases. A severity grading system of oscillometric parameters was developed to help the interpretation of oscillometry in clinical practice.

New Mutations in cls Lead to Daptomycin Resistance in a Clinical Vancomycin- and Daptomycin-Resistant Enterococcus faecium Strain.

Daptomycin (DAP), a last-resort antibiotic for treating Gram-positive bacterial infection, has been widely used in the treatment of vancomycin-resistant enterococci (VRE). Resistance to both daptomycin and vancomycin leads to difficulties in controlling infections of enterococci. A clinical multidrug-resistant Enterococcus faecium EF332 strain that shows resistance to both daptomycin and vancomycin was identified, for which resistance mechanisms were investigated in this work. Whole-genome sequencing and comparative genomic analysis were performed by third-generation PacBio sequencing, showing that E. faecium EF332 contains four plasmids, including a new multidrug-resistant pEF332-2 plasmid. Two vancomycin resistance-conferring gene clusters vanA and vanM were found on this plasmid, making it the second reported vancomycin-resistant plasmid containing both clusters. New mutations in chromosomal genes cls and gdpD that, respectively, encode cardiolipin synthase and glycerophosphoryl diester phosphodiesterase were identified. Their potential roles in leading to daptomycin resistance were further investigated. Through molecular cloning and phenotypic screening, two-dimensional thin-layer chromatography, fluorescence surface charge test, and analysis of cardiolipin distribution patterns, we found that mutations in cls decrease surface negative charges of the cell membrane (CM) and led to redistribution of lipids of CM. Both events contribute to the DAP resistance of E. faecium EF332. Mutation in gdpD leads to changes in CM phospholipid compositions, but cannot confer DAP resistance. Neither mutation could result in changes in cellular septa. Therefore, we conclude that the daptomycin resistance of E. faecium EF332 is conferred by new cls mutations. This work reports the genetic basis for vancomycin and daptomycin resistance of a multidrug-resistant E. faecium strain, with the finding of new mutations of cls that leads to daptomycin resistance.

Evaluation of culturable 'last-resort' antibiotic resistant pathogens in hospital wastewater and implications on the risks of nosocomial antimicrobial resistance prevalence.

Antimicrobial resistance has been recognized as an important emerging environmental pollutant. 'Last-resort' antibiotics including tigecycline, polymyxin E, daptomycin, vancomycin and linezolid are the 'last line of defence' for antibiotic resistant pathogen infections. Therefore, the presence of 'last-resort' antibiotic resistant pathogens in hospital environments and the nosocomial transmission of 'last-resort' antibiotic resistance poses a grave threat to the well-being of patients. In this work, the extent of resistance to 'last-resort' antibiotics in culturable pathogens in hospital wastewater was investigated. Resistance to 'last-resort' antibiotics were quantified for 1384 culturable Enterobacteriaceae, Enterococcus, Staphylococcus, and Pseudomonas strains. With these investigations, several significant findings were made: (1) a very high level of resistance to 'last-resort' antibiotics was found; (2) multiple resistance to antibiotics, including 'last-resort' antibiotics, was prevalent; (3) a high level of 'last-resort' antibiotic resistance phenotype-genotype inconsistency was found, suggesting knowledge gap for resistance mechanisms; 4) tet(X4)-containing tigecycline-resistant Gram-positive pathogens were found for the first time; 5) wastewater treatment processes are effective in preventing the release of 'last-resort' antibiotic resistant pathogens to the environment. This investigation reveals the severe situation on 'last-resort' resistance in the hospital environment, and implies high risk for nosocomial transmission of 'last-resort' antibiotic resistant pathogens.

STUB1 regulates antiviral RNAi through inducing ubiquitination and degradation of Dicer and AGO2 in mammals.

RNA interference (RNAi) is an intrinsic antiviral immune mechanism conserved in diverse eukaryotic organisms. However, the mechanism by which antiviral RNAi in mammals is regulated is poorly understood. In this study, we uncovered that the E3 ubiquitin ligase STIP1 homology and U-box-containing protein 1 (STUB1) was a new regulator of the RNAi machinery in mammals. We found that STUB1 interacted with and ubiquitinated AGO2, and targeted it for degradation in a chaperon-dependent manner. STUB1 promoted the formation of Lys48 (K48)-linked polyubiquitin chains on AGO2, and facilitated AGO2 degradation through ubiquitin-proteasome system. In addition to AGO2, STUB1 also induced the protein degradation of AGO1, AGO3 and AGO4. Further investigation revealed that STUB1 also regulated Dicer's ubiquitination via K48-linked polyubiquitin and induced the degradation of Dicer as well as its specialized form, termed antiviral Dicer (aviDicer) that expresses in mammalian stem cells. Moreover, we found that STUB1 deficiency up-regulated Dicer and AGO2, thereby enhancing the RNAi response and efficiently inhibiting viral replication in mammalian cells. Using the newborn mouse model of Enterovirus A71 (EV-A71), we confirmed that STUB1 deficiency enhanced the virus-derived siRNAs production and antiviral RNAi, which elicited a potent antiviral effect against EV-A71 infection in vivo. In summary, our findings uncovered that the E3 ubiquitin ligase STUB1 was a general regulator of the RNAi machinery by targeting Dicer, aviDicer and AGO1-4. Moreover, STUB1 regulated the RNAi response through mediating the abundance of Dicer and AGO2 during viral infection, thereby providing novel insights into the regulation of antiviral RNAi in mammals.

A comparison between exogenous carriers enhanced aerobic granulation under low organic loading in the aspect of sludge characteristics, extracellular polymeric substances and microbial communities.

In this study, polymeric ferric sulfate (PFS), aluminum sulfate (AS) and diatomite were added to enhance the aerobic granulation under low organic loading rate (OLR) of 0.6 kg·COD/(m3·d), and their effects of aerobic granule formation, extracellular polymeric substances (EPS) secretion and microbial community were investigated. The results showed that adding carriers could facilitated the growth of aerobic granules and improve the sludge settleability and biomass retention. Nutrient removal efficiencies were also enhanced. Compared with diatomite, adding PFS and AS resulted in more significant increase in EPS production, especially for the extracellular proteins. For microbial community, the dominated bacteria (Zoogloea, 18.47-23.95%) in the mature granular consortia were similar. Moreover, the introduction of PFS and diatomite contributed to the enrichment of Paracoccus, which was responsible for denitrification. Adding carriers potentially activated the functional genes related to metabolism and genetic information processing, and PFS had the most significant effects.

miR-223-3p targets FBXW7 to promote epithelial-mesenchymal transition and metastasis in breast cancer.

BACKGROUND: Breast cancer is the most common malignant tumor diagnosed in women. It is the second leading cause of cancer-related death among women in the world. Aberrant expression of microRNAs (miRNAs) have been identified to be involved in the development and progression of breast cancer. The aim of this study was to investigate the function of miR-223-3p in breast cancer progression and metastasis. METHODS: qRT-PCR was used to analyze the expression levels of miR-223-3p in breast cancer tissues and cell lines. Wound healing and Matrigel assays were used to examine cell motility and invasiveness. FBXW7 3'-UTR construct and luciferase reporter assays were performed for the target gene. RESULTS: miR-223-3p was overexpressed in breast cancer tissue and cell lines. A high level of miR-223-3p was associated with poor prognosis in breast cancer patients. In addition, overexpressed miR-223-3p promoted the migration and invasion of breast cancer cells in vitro and in vivo. Mechanistically, we found that tumor suppressor gene FBXW7 is a target of miR-223-3p. Luciferase activity reporter assay indicated miR-223-3p could directly bind with the 3'-UTR of FBXW7. miR-223-3p exhibited its oncogenic role partly by decreasing FBXW7 expression, and consequently promoted the invasion and metastasis of breast cancer cells. CONCLUSIONS: Our study revealed a physical and functional relationship among miR-223-3p and FBXW7. By negatively regulating FBXW7 expression, miR-223-3p exerts a tumor promotion role promoting cell invasion and metastasis in breast cancer.

Effect of exercise on microglial activation and transcriptome of hippocampus in fluorosis mice.

Fluorosis is a widespread endemic disease. Reports have shown that high fluoride causes the dysfunction of central nervous system (CNS) in animals. The neurotoxicity of fluoride may be related to the activation of microglia. Moreover, numerous studies have found that exercise facilitates the plasticity of structure and function in CNS, partly owing to the regulation of microglia activation. The present study was conducted to explore the effect of exercise on the microglial activation of hippocampus in fluorosis mice. One hundred adult female Institute of Cancer Research (ICR) mice were randomly divided into 4 groups: control group (group C, distilled water by gavage); exercise group (group E, distilled water by gavage and treadmill exercise); fluoride group [group F, 24 mg/kg sodium fluoride (NaF) by gavage]; fluoride plus exercise group (group F + E, 24 mg/kg NaF by gavage and treadmill exercise). After 8 weeks, hippocampal morphological structure, microglial activation and RNA transcriptome of mice in each group were evaluated by hematoxylin and eosin (HE) staining, Nissl staining, immunohistochemistry (IHC), quantitative real time PCR (QRT-PCR) and transcriptome sequencing. We discovered that the number of M1-type microglia in fluorosis-mice hippocampus was significantly increased when compared to group C; group F + E showed a decrease in the number of M1-type microglia with the comparison to group F. In addition, the hippocampal transcriptome analysis showed that 576 differential expression genes (DEG) were confirmed in group F, compared to group C, and 670 DEG were differently expressed in group F + E when compared to group F. Gene Ontology (GO) analysis showed that changed genes were implicated in regulation of transcription, DNA-templated, integral component of membrane and adenosine triphosphate (ATP) binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of 670 DEG was helpful to find neuroactive ligand-receptor interaction pathway. In conclusion, these results indicate that treadmill running inhibits the excessive activation of microglia in hippocampus of the fluoride-toxic mice, accompanied with the alteration of neuroactive ligand-receptor interaction pathway.

A Clinical Extensively-Drug Resistant (XDR) Escherichia coli and Role of Its ß-Lactamase Genes.

An extensively-drug resistant (XDR) Escherichia coli W60 was isolated from the urine sample of a patient. The genetic basis for its XDR phenotype was investigated, particularly the basis for its resistance toward ß-lactam/BLI (ß-Lactamase Inhibitor) combinations. Following determination of the XDR phenotype, third generation genomic sequencing was performed to identify genetic structures in E. coli W60. Further cloning analysis was performed to identify determinants of ß-lactam/BLI combination resistance. It was found that E. coli W60 is resistant to nearly all of the tested antibiotics including all commonly used ß-lactam/BLI combinations. Analysis of the genomic structures in E. coli W60 showed two novel transferable plasmids are responsible for the resistance phenotypes. Further genetic analysis showed bla NDM-5 leads to high resistance to ß-lactam/BLI combinations, which was enhanced by co-expressing ble MBL. pECW602 harbors a truncated bla TEM that is not functional due to the loss of the N-terminal signal peptide coding region. Research performed in this work leads to several significant conclusions: the XDR phenotype of E. coli W60 can be attributed to the presence of transferable multidrug resistance plasmids; NDM-5 confers high resistance to ß-lactam/BLI combinations; co-expression of ble MBL enhances resistance caused by NDM-5; the signal peptides of TEM type ß-lactamases are essential for their secretion and function. Findings of this work show the danger of transferable multidrug resistance plasmids and metallo-ß-lactamases, both of which should be given more attention in the analysis and treatment of multidrug resistant pathogens.

Fluoride exposure altered metabolomic profile in rat serum.

It is well known that serum is an ideal and potential choice to reflect the toxicity of fluoride. However, the effects of fluoride on serum metabolome have not been reported until now. In this study, the models of 3-week-old rats exposed fluoride by breast milk and 11-week-old rats exposed fluoride via breast milk and drinking water containing sodium fluoride (100 mg/L) were established. Using Ultra Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (UPLC-MS/MS), as compared with control group, 28 negative (NEG) and 52 positive (POS) metabolites were significantly up-regulated, meanwhile 30 NEG and 21 POS significantly down-regulated metabolites were found in serum of 3-week-old rats exposed to fluoride. For 11-week-old fluorosis rats, there were 119 NEG and 65 POS metabolites significantly increased, and 7 NEG, 5 POS metabolites were obviously decreased. Importantly, nicotinamide, adenosine, 1-Oleoyl-sn-glycero-3-phosphocholine (OGPC), and 1-Stearoyl-sn-glycerol 3-phosphocholine (SGPC) were shared by two models. The metabolites of urea cycle, such as urea and N2-Acetyl-l-ornithine, betaine as a methyl donor, were regarded to reflect the fluorosis degree. These metabolites could be the potential markers of fluorosis, contributing to the prevention and treatment of fluorosis.

Erinacerins, Novel Glioma Inhibitors from Hericium erinaceus, Induce Apoptosis of U87 Cells through Bax/Capase-2 Pathway.

BACKGROUND: Glioma is the most common tumor of the central nervous system. Hericium erinaceus, which has been reported to have a variety of pharmacological activities, is a widely used Traditional Chinese Medicine (TCM), and also a kind of delicious food accepted by the public. METHODS AND RESULTS: In this study, two new natural products, compounds 1 and 2, were isolated and identified from Hericium erinaceus. They were named erinacerin O and erinacerin P, respectively, after the structural identification, and their effects on human glioma cell line U87 were evaluated. Erinacerin P (2) exhibited obvious cytotoxicity on human glioma cell line U87. The IC50 value of 2 was 19.32µg/mL. The results showed that the apoptosis of U87 cells treated with 2 increased and the morphology of U87 cells altered significantly. Flow cytometry experiment showed that 2 could significantly increase the apoptosis rate of U87 cells and reduce DNA replication. Western blot results suggested the Bax/capase-3 pathway was involved in the U87 cell apoptosis induced by 2. CONCLUSION: Erinacerin O and Erinacerin P are novel compounds obtained from Hericium erinaceus and Erinacerin P could be a potential novel glioma inhibitor.

Anti-inflammatory effect of up-regulated microRNA-221-3p on coronary heart disease via suppressing NLRP3/ASC/pro-caspase-1 inflammasome pathway activation.

OBJECTIVE: As some evidence has demonstrated the role of microRNA-221 (miR-221) on coronary heart disease (CHD), the aim of the present study was to investigate the effect of miR-221-3p on CHD via regulating NLRP3/ASC/pro-caspase-1 inflammasome pathway. METHODS: Sixty CHD patients and 60 healthy controls were collected to detect the expression of miR-221-3p, NLRP3, ASC, pro-caspase-1 in peripheral blood and the contents of related factors in serum. The rats model of CHD was injected with miR-221-3p agomir or miR-221-3p antagomir to explore its functions in miR-221-3p, NLRP3, ASC and pro-caspase-1 expression, electrocardiogram data, cardiomyocytes apoptosis, myocardial injury, inflammatory reaction and oxidative stress of CHD rats. RESULTS: MiR-221-3p declined and NLRP3, ASC and pro-caspase-1 raised in CHD. Up-regulated miR-221-3p reduced the change value of J-point and T-wave, decreased NLRP3, ASC and pro-caspase-1 expression, suppressed apoptosis in cardiomyocytes, as well as suppressed myocardial injury, inflammatory reaction and oxidative stress in CHD rats. CONCLUSION: This study highlights that up-regulated miR-221-3p suppresses the overactivation of NLRP3/ASC/pro-caspase-1 inflammasome pathway and has an anti-inflammatory effect in CHD. Thus, miR-221-3p may serve as a potential target for the treatment of CHD.

Fecal microbiota transplantation improves metabolism and gut microbiome composition in db/db mice.

Fecal microbiota transplantation (FMT) has become an effective strategy to treat metabolic diseases, including type 2 diabetes mellitus (T2DM). We previously reported that the intestinal microbiome had significant difference between individuals with normal glucose tolerance and T2DM in Chinese Kazak ethnic group. In this study, we investigated the effects of transplanted fecal bacteria from Kazaks with normal glucose tolerance (KNGT) in db/db mice. The mice were treated with 0.2 mL of fecal bacteria solution from KNGT daily for 10 weeks. We showed that the fecal bacteria from KNGT successfully colonized in the intestinal tract of db/db mice detected on day 14. In the FMT-treated db/db mice, the levels of fasting blood glucose, postprandial glucose, total cholesterol, triglyceride, and low-density lipoprotein-cholesterol were significantly downregulated, whereas high-density lipoprotein-cholesterol levels were upregulated. In the FMT-treated db/db mice, Desulfovibrio and Clostridium coccoides levels in gut were significantly decreased, but the fecal levels of Akkermansia muciniphila and colon histone deacetylase-3 (HDAC3) protein expression were increased. At 8 weeks, both intestinal target bacteria and HDAC3 were correlated with glycolipid levels; Akkermansia muciniphila level was positively correlated with HDAC3 protein expression (r = +0.620, P = 0.037). Our results suggest that fecal bacteria from KNGT could potentially be used to treat diabetic patients.

Intestinal fungal dysbiosis in mice induced by fluoride.

To explore the effects of fluoride on intestinal fungi in mice, the internal transcriptional spacer (ITS) region in colon feces of mice exposed to 100 mg sodium fluoride (NaF)/L of distilled water for 60 days were sequenced. Results showed that, there were 305 operational taxonomic units (OTUs) unique to the control group, 154 OTUs to the fluoride group, and 295 OTUs were detected in both groups. There was no significant difference in relative species abundance between the two groups at phylum levels. Compared with control group, Ustilaginomycetes class, showed a significant change in fluoride group. At the genus level, Epicoccum, Penicillium, Microdochium, Plectosphaerella and Pluteus were significantly affected by fluoride exposure. Among them, there was a strong positive correlation between Penicillium and Pluteus (+0.43). Therefore, it showed that fluoride can influence the relative species abundance of intestinal fungi in mice, mainly at the genus levels. It can provide some new ideas about the harmful effects of fluorosis on intestinal fungal homeostasis.

Fluoride-Induced Alteration in the Diversity and Composition of Bacterial Microbiota in Mice Colon.

Fluoride, as an environmental toxin, causes damage to intestinal mucosa. It may promote pathogen infection by increasing the intestinal mucosa permeability. In this study, the colonic fecal samples from the control group (C group, 0 mg/L NaF for 60 days) and the fluoride group (F group, 100 mg/L NaF for 60 days) were subjected to high-throughput 16S rRNA sequencing to verify the effects of fluoride on the colonic flora of animals. Results revealed a total of 253 operative taxonomical units (OTUs) in two groups, and 22 unique OTUs occurred in the F group. Fluoride increased the microbiota diversity and species richness of the colon. Concretely, the abundance of the Tenericutes was increased at the level of the phyla in the F group. In addition, in the F group, significant differences at the genus level were observed in Faecalibaculum, Alloprevotella, [Eubacterium]_xylanophilum_group, Prevotellaceae_UCG-001, and Ruminiclostridium_9, compared to the C group. Among them, except for the reduction in Faecalibaculum, the other four bacteria were increased in the F group. In summary, the intestinal microbial composition of mice was reconstituted by the presence of fluoride, and the significantly changing bacteria may partly account for the pathogenesis of fluoride-induced intestinal dysfunction.

RIPK1 can mediate apoptosis in addition to necroptosis during embryonic development.

RIPK1 has emerged as a key effector in programmed necrosis or necroptosis. This function of RIPK1 is mediated by its protein serine/threonine kinase activity and through the downstream kinase RIPK3. Deletion of RIPK1 prevents embryonic lethality in mice lacking FADD, a signaling adaptor protein required for activation of Caspase 8 in extrinsic apoptotic pathways. This indicates that FADD-mediated apoptosis inhibits RIPK1-dependent necroptosis to ensure successful embryogenesis. However, the molecular mechanism for this critical regulation remains unclear. In the current study, a novel mouse model has been generated, by disrupting a potential caspase cleavage site at aspartic residue (D)324 in RIPK1. Interestingly, replacing D324 with alanine (A) in RIPK1 results in midgestation lethality, similar to the embryonic defect in FADD-/- mice but in stark contrast to the normal embryogenesis of RIPK1-/- null mutant mice. Surprisingly, disrupting the downstream RIPK3 alone is insufficient to rescue RIPK1D324A/D324A mice from embryonic lethality, unless FADD is deleted simultaneously. Further analyses reveal a paradoxical role for RIPK1 in promoting caspase activation and apoptosis in embryos, a novel mechanism previously unappreciated.