Purine Metabolic Pathway Research Articles

Profiles of Sterigmatocystin and Its Metabolites during Traditional Chinese Rice Wine Processing.

Mycotoxin pollution is widespread in cereal, which greatly threatens food security and human health. In this study, the migration and transformation of sterigmatocystin (STG) mycotoxin during the contaminated rice wine processing was systematically assessed. QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) coupled with ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UPLC−MS/MS) method was firstly established for STG analysis in rice wine. It was found that high levels of rice leaven caused a significant reduction in STG in the fermented rice and wine, which was mainly due to the adsorption of yeast cells and Rhizopus biological degradation. However, compared with rice, the levels of STG in separated fermented wine was significantly decreased by 88.6%, possibly attributed to its high log Kow (3.81) and low water solubility (1.44 mg/L). The metabolites of STG (i.e., monohydroxy STG) were identified in rice wine fermentation for the first time. Moreover, STG disturbed the metabolic profile rice wine composition mainly by glycine, serine and threonine metabolism, alanine, aspartate and glutamate metabolism, purine metabolism pathway, particularly with regard to eight amino acids and sixteen lipids. This study elucidated the STG migration and transformation mechanism during the rice wine processing. The finding provided new analytical method for mycotoxin exposure and pollutant in food production, which may support agricultural production and food security.

Is there any biological insight (or respite) for insects exposed to plastics? Measuring the impact on an insects central carbon metabolism when exposed to a plastic feed substrate

Insects used to treat organic waste streams and produce valuable protein products are increasingly exposed to plastic contaminated source material assimilating plastic carbon into organic biomass, which is pervasive and hazardous to organisms. Our understanding of this increased insect-plastic interaction remains limited and needs urgent scientific attention if plastic biodegradation and production rates of quality protein are to be improved. Herein, we investigated the biochemical impact of various plastics using three insect models. Black Soldier Fly (BSF), Mealworm (MW), and Wax Moth (WM) larva were each exposed to a plastic substrate (PET, PE, PS, Expanded PE, PP, and PLA) as the primary carbon source for five days to explore any positive metabolic benefits in terms of insect performance and plastic degradation potential. Central carbon metabolism (CCM) metabolites were analyzed via a targeted tMRM liquid chromatography triple quadrupole mass spectrometry (LC-QqQ-MS) method. Unique expressed pathways were observed for each insect model. When reared on PET, BSF larvae were found to have an elevated pyrimidine metabolism, while the purine metabolism pathway was strongly expressed on other plastics. BSF also exhibited a downregulated Vitamin B6 metabolism across all plastics, indicating a likely gut-symbiont breakdown. The MW and WM model insects were metabolically more active on PLA and expanded foam plastics. Further, WM exhibited an elevation in Vitamin B6 metabolism. This data suggests a positive insect-specific interaction towards certain plastic types that warrants further investigation. It is anticipated that through deeper insight into the metabolic impact and benefits afforded from certain plastics, an insect biotransformation pipeline can be established that links fit-for-purpose insect models to individual plastic types that address our growing plastic waste issue.

Effect of the ethyl acetate extract of Sophora flavescens Aiton on diabetic retinopathy based on untargeted retinal metabolomics

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and a leading cause of vision impairment and blindness, which lacks effective diagnostic measures and therapeutic options. Sophora flavescens Aiton or “Kushen” is a traditional Chinese medicine used since ancient times, either alone or in combination, to clear heat, dampness, and tearing, and to treat ocular diseases and improve eyesight. Additionally, the flavonoids of Sophora flavescens Aiton extracted using ethyl acetate (EtOAc) (SFE) is effective in managing diabetes and diabetic vascular complications. In this study, we explored the pharmacodynamic effects and material basis of action of SFE on DR for the first time and elucidated the mechanism based on untargeted retinal metabolomics. Results from the pharmacodynamic studies showed that SFE could reduce blood glucose levels in rats, regulate serum lipopolysaccharide, tauroursodeoxycholic acid, and trimethylamine oxide levels, and significantly improve the structure of retina in rats with DR. Moreover, SFE could protect the blood-retinal barrier, reduce angiogenesis and capillary formation, and inhibit retinal nerve cell apoptosis. A total of 13 compounds were identified in the aqueous humor and retina, which were dihydroflavonoid, isoflavonoid, pterostane flavonoid, chalcone, and dihydroflavonol derivatives. In addition, 39 differential metabolites were screened based on retinal metabolomics data and 23 were found to be affected by SFE, indicating its anti-DR effect by regulating the synthetic metabolic pathways, including lactose, bile acid, glycerophospholipid, arginine, purine, and pyrimidine metabolism pathways. Collectively, our findings elucidated the effects, material basis, and treatment mechanism of SFE on DR systematically and could lay the foundation for promoting the clinical application of Sophora flavescens Aiton.

Metabolomics Based on Peripheral Blood Mononuclear Cells to Dissect the Mechanisms of Chaigui Granules for Treating Depression.

Chaigui granules were a traditional Chinese medicine (TCM) preparation with antidepressant effects derived from a famous antidepressant prescription. It was of great significance to clarify the antidepressant mechanism of Chaigui granules for the clinical application of this drug. In this study, a chronic unpredictable mild stress (CUMS) depression model was successfully established, and behavioral indicators were used to evaluate the antidepressant effect. Second, the CD4+, CD8+, and CD4+/CD8+ levels were detected in peripheral blood. Meanwhile, the amount of inflammatory cytokines was determined in serum. Correspondingly, LC/MS-based peripheral blood mononuclear cell (PBMC) metabolomics was used to investigate vital metabolic pathways participating in the antidepressive effects of Chaigui granules. Finally, bioinformatics technology was further employed to discover the potential antidepressant mechanism of Chaigui granules regulating the immune system. The results suggested that the administration of Chaigui granules significantly improved CUMS-induced depressive symptoms. Chaigui granules could improve immune function by regulating T lymphocyte subsets, increasing anti-inflammatory cytokine levels of IL-2 and IL-10, and reducing pro-inflammatory cytokine levels of TNF-α, IL-1β, and IL-6. In addition, metabolomics results of PBMCs showed that Chaigui granules improved 14 of the 25 potential biomarkers induced by CUMS. Metabolic pathway analyses indicated that purine metabolism was the critical metabolic pathway regulated by Chaigui granules. Furthermore, correlation analysis indicated that 13 key biomarkers were related to immune-related indicators. The metabolite–gene network of 13 key biomarkers was investigated by using bioinformatics. The investigation showed that 10 targets (5′-nucleotidase ecto; 5′-nucleotidase, cytosolic IB; 5′-nucleotidase, cytosolic II; etc.), mainly belong to the purine metabolism, might be potential targets for Chaigui granules to exert their antidepressant effects by improving immune function impairment. Together, our results suggested that Chaigui granules might exert antidepressant effects by improving immune function and regulating the purine metabolic pathway in PBMCs. This work used PBMCs metabolomics as an entry point to study the antidepressant mechanism of Chaigui granules, which provided a new way to elucidate the mechanism of a traditional Chinese medicine prescription.

Metabolomics combined with systematic pharmacology reveals the therapeutic effects of Salvia miltiorrhiza and Radix Pueraria lobata herb pair on type 2 diabetes rats

• DG is a famous TCM herb pair to treat T2DM. • DG makes changes of 12 biomarkers: alanine, n-butyrate, succinic acid, lactic acid, L-proline, valine, leucine, glutamate, glucose, isoleucine, α-ketoisovalerate, and hypoxanthine. • DG mainly functions through Purine Metabolism, Galactose Metabolism, and Arginine and Proline Metabolism pathways to treat T2DM. • DG adjust the mRNA levels of ADCY2, MAOB, AKR1B1, XDH, PDE3A, NOS2, and NOS3. Salvia miltiorrhiza and Radix Pueraria lobata herb pair is the core of the huoxuehuayu method to treat type 2 diabetes in Chinese. However, the mechanisms of this herb pair remain unclear. In this study, after fecal samples of rats were analyzed, 12 biomarkers and 15 pathways were identified by metabolomics. Then systematic pharmacology predicted 138 targets and 245 pathways. After combining these results with 3 overlapping pathways, a complete network was built. The 7 hub targets in it were verified by quantitative polymerase chain reaction (qPCR). Compared with the Model group, the mRNA level of ADCY2 (P＜0.05), MAOB, (P＜0.01), AKR1B1 (P＜0.05), XDH (P＜0.05), PDE3A (P＜0.05), and NOS2 (P＜0.01) were decreased, while the level of NOS3 (P＜0.05) was elevated after herb pair treatment. The results indicate treating effect of this herb pair is related to reducing oxidative stress, inflammation, and improving energy metabolism.

Analysis of the molecular mechanism of inosine monophosphate deposition in Jingyuan chicken muscles using a proteomic approach

Inosine monophosphate (IMP) is an indicator of meat taste, and the molecular mechanism underlying IMP deposition in muscle tissues is important to developing superior poultry breeds. The aim of this study was to identify the key proteins regulating IMP deposition in different muscle groups of 180-day-old Jingyuan chickens (Hen) using a proteomics-based approach. We identified 1,300 proteins in the muscle tissues of Jingyuan chickens, of which 322 were differentially expressed between the breast and leg muscles (129 proteins were highly expressed in breast muscles and 193 proteins were highly expressed in leg muscles). PGM1, PKM2, AK1, AMPD1, and PurH/ATIC were among the differentially expressed proteins (DEPs) involved in the purine metabolism pathway, of which purH was highly expressed in leg muscles, while the others were highly expressed in breast muscles. The proteomics screening results were verified by PRM, qPCR, and western blotting, showing consistency with the proteomics results. Our findings are not only significant in terms of protecting the Jingyuan chicken germplasm resources, but also provide the molecular basis for generating high-quality broiler chicken breeds.

Dynamic Alterations of the Gut Microbial Pyrimidine and Purine Metabolism in the Development of Liver Cirrhosis.

Background: Liver cirrhosis is the common end-stage of liver disease which lacks effective treatment, thus studies to determine prevention targets are an urgent need. The intestinal microbiota (IM) play important roles in modulating liver diseases which are mediated by microbial metabolites. Despite decades of growing microbial studies, whether IM contribute to the development of cirrhosis and the intimate metabolic link remain obscure. Here, we aimed to reveal the dynamic alterations of microbial composition and metabolic signatures in carbon tetrachloride (CCl4)-induced liver cirrhosis mice. Methods: CCl4-treated mice or normal control (NC) were sacrificed (n = 10 per group) after 5 and 15 weeks of intervention. The disease severity was confirmed by Masson’s trichrome or Sirius red staining. Metagenomics sequencing and fecal untargeted metabolomics were performed to evaluate the composition and metabolic function of IM in parallel with the development of cirrhosis. Results: The CCl4-treated mice presented liver fibrosis at 5 weeks and liver cirrhosis at 15 weeks indicated by collagen deposition and pseudo-lobule formation, respectively. Mice with liver cirrhosis showed distinct microbial composition from NC, even in the earlier fibrosis stage. Importantly, both of the liver fibrosis and cirrhosis mice were characterized with the depletion of Deltaproteobacteria (p < 0.05) and enrichment of Akkermansia (p < 0.05). Furthermore, fecal metabolomics revealed distinguished metabolomics profiles of mice with liver fibrosis and cirrhosis from the NC. Notably, pathway enrichment analysis pointed to remarkable disturbance of purine (p < 0.001 at 5 weeks, p = 0.034 at 15 weeks) and pyrimidine metabolic pathways (p = 0.005 at 5 weeks, p = 0.006 at 15 weeks) during the development of liver cirrhosis. Interestingly, the disorders of pyrimidine and purine metabolites like the known microbial metabolites thymidine and 2′-deoxyuridine had already occurred in liver fibrosis and continued in cirrhosis. Conclusion: These novel findings indicated the crucial role of IM-modulated pyrimidine and purine metabolites in the development of liver cirrhosis, which provides microbial targets for disease prevention.

Effects of Docosahexanoic Acid on Gut Microbiota and Fecal Metabolites in HIV-Infected Patients With Neurocognitive Impairment: A 6-Month Randomized, Double-Blind, Placebo-Controlled Trial.

Neurocognitive impairment (NCI) and gut microbiota dysbiosis are prevalent in patients with HIV infection. Docosahexanoic acid (DHA) supplementation may alleviate multiple neurocognitive diseases symptoms and plays important role in regulating gut microbiota. However, it is not known whether DHA algae oil supplements can alleviate neurocognitive impairment (NCI) and regulate gut microbiota and fecal metabolites. A randomized, double-blind, placebo-controlled trial was performed on 68 HIV-infected patients with NCI. Participants were randomized to receive a 3.15 g daily DHA algae oil supplement or placebo for 6 months. We collected blood and fecal samples from these patients before and after the trial. Mini mental state examination (MMSE) and neuropsychological tests (NP tests) were administered to assess the cognitive status of participants. The influence of DHA algae oil on the gut microbiota, fecal metabolomics, plasma proinflammatory, and oxidative stress factors was also investigated. There were no significant changes in NCI according to global diagnosis score (GDS) and MMSE score within the two groups, while patients receiving DHA had improvement in several blood lipids, pro-inflammatory and oxidative stress factors. The DHA supplement increased α-diversity indexes, increased abundances of Blautia, Bifidobacterium, Dorea, Lactobacillus, Faecalibacterium, Fusobacterium, and Agathobacter, and decreased abundances of Bacteroides and Prevotella_9. Furthermore, DHA supplement was correlated with improved fecal lipid metabolites as indicated by ceramides, bile acids, glycerophospholipids. In addition, the DHA supplement was associated with altered cholesterol metabolism and purine metabolism pathways. A daily supplement of DHA algae oil for 6 months has been shown to promote favorable transformations in gut microbiota, profiles of fecal metabolomic, and factors responsible for proinflammatory and oxidative stress, which might be beneficial for the prognosis of HIV-infected patients with NCI in the long-term.Clinical Trial Registrationhttps://clinicaltrials.gov/ct2/show/NCT04242004, identifier: NCT04242004.

Suppression of Thiol-Dependent Antioxidant System and Stress Response in Methicillin-Resistant Staphylococcus aureus by Docosanol: Explication Through Proteome Investigation

The present study was aimed to investigate the effect of docosanol on the protein expression profile of methicillin-resistant Staphylococcus aureus (MRSA). Thus, two-dimensional gel electrophoresis coupled with MALDI-TOF MS technique was utilized to identify the differentially regulated proteins in the presence of docosanol. A total of 947 protein spots were identified from the intracellular proteome of both control and docosanol treated samples among which 40 spots were differentially regulated with a fold change greater than 1.0. Prominently, the thiol-dependent antioxidant system and stress response proteins are downregulated in MRSA, which are critical for survival during oxidative stress. In particular, docosanol downregulated the expression of Tpx, AhpC, BshC, BrxA, and YceI with a fold change of 1.4 (p = 0.02), 1.4 (p = 0.01), 1.6 (p = 0.002), 4.9 (p = 0.02), and 1.4 (p = 0.02), respectively. In addition, docosanol reduced the expression of proteins involved in purine metabolic pathways, biofilm growth cycle, and virulence factor production. Altogether, these findings suggest that docosanol could efficiently target the antioxidant pathway by reducing the expression of bacillithiol and stress-associated proteins.

Genomic characteristics of a novel strain Lactiplantibacillus plantarum X7021 isolated from the brine of stinky tofu for the application in food fermentation

Lactiplantibacillus plantarum X7021 is a novel strain originated from the brine of stinky tofu. In order to investigate the application potential of the strain in food industry, the genomic characteristics as well as some metabolic features were studied using comparison genomics and transcriptional assay. The complete genome of X7021includes a 3,407,054 bp chromosome with 3259 protein coding sequences, and 6 plasmids. L. plantarum strains, WCFS1, JDM1, and ST-III were selected for comparative genomic analysis. Results revealed that X7021 is safe for the application in foods with less antibiotic resistance and virulence genes. The strain has 25 complete phosphotransferase system transporters and strong proteolytic system for its adaptability to various foodstuffs. The strain containes a complete purine metabolic pathway incorporating 4 permeases, resulting in the reductions of 38.9% guanine, 26.1% hypoxanthine and 70.2% xanthine during the soymilk fermentation. Soy isoflavone glycosides could be converted to corresponding aglycones by two β-glucosidases. The strain could grow in 700 mg/L nitrite and entirely degrade 100 mg/L nitrite during 24 h based on highly active nitrite transporter and nitrite reductase. Accordingly, the results suggest that L. plantarum X7021 is a prospect starter candidate for the fermentation of plant foodstuffs.

The influence of microbial bacterial proteins on metabolites in the chilled tan sheep meat

This study aims to investigate experimentally the influence of microbial bacterial proteins on microbial metabolites in the chilled storage of Tan Sheep meat based on the surface enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) and gas chromatography-time of flight-mass spectrometry (GC-TOF MS). The correlation analysis of differentially abundant proteins and differential metabolites detected simultaneously in different storage periods has been carried out by heatmap analysis. The results show that 30 differential expressed metabolites were statistically significant. These metabolites were identified as potential spoilage biomarkers. Among of them, 25 differential expressed metabolites can be matched to KEGG metabolic pathways. cyano-amino-acid pathway, pentose phosphate pathway, histidine pathway, purine metabolic pathways, lanine, aspartic acid and glutamate pathway were highly active. Therefore, the differentially abundant proteins contents of microbiology in metabolism can lead to differential effects on metabolic pathways.

Effects of cocoa on altered metabolite levels in purine metabolism pathways and urea cycle in Alzheimer's disease in C. elegans

Dietary interventions have gained much attention as alternative therapies in aging-associated diseases. Epidemiological studies suggest that polyphenols (PPs) play an important role in this regard. Cocoa is rich in PPs, greater in amount than in teas and red wine. This study aimed to characterize the age-associated and amyloid-β (Aβ)-induced changes in metabolism in C. elegans and the effects of cocoa supplementation. An untargeted Gas Chromatography-Mass Spectrometry (GC-MS) approach was used to determine the changes in endogenous metabolite levels in wild-type and a transgenic C. elegans strain expressing pan-neuronal Aβ (GRU102). Aging appeared to alter some amino acid levels in C. elegans. Cocoa supplementation reduced leucine and tyrosine levels in old age (day 12). GRU102 showed higher proline and asparagine relative to control worms at a young age (day 4) which may have a connection with cognitive deficits in Alzheimer's disease (AD). Cocoa reduced the elevated levels of these two amino acids to the levels in the control worms. The purine derivative, hypoxanthine was higher in GRU102 relative to the control worms at their middle age (day 8) where the elevated are known to contribute to memory deficits in AD. Cocoa supplementation reduced the elevated hypoxanthine to normal levels. Aβ expression showed alterations in the urea cycle in worms in their middle age as indicated by increased ornithine.

Transcriptomics integrated with metabolomics reveals the effect of Lycium barbarum polysaccharide on apoptosis in Nile tilapia (Oreochromis niloticus)

Lycium barbarum polysaccharide (LBP) is one of the main active ingredients in the fruit of L. barbarum L. It has been used as herbal medicine for thousands of years in China. In this study, Nile tilapia (Oreochromis niloticus) was taken as the research object. After feeding tilapia with 5 different doses of LBP (0 mg/kg, 500 mg/kg, 1000 mg/kg, 1500 mg/kg, 2000 mg/kg) for 55 d, it was found that LBP could promote the growth of tilapia, and this effect was the strongest at Group 1500 mg/kg. Apoptosis analysis in the liver and spleen showed that dietary supplementation with 1000 mg/kg LBP had the best protective effect on the spleen and liver in tilapia. Combined transcriptomics and metabolomics of the spleen in tilapia at Group 0 mg/kg and 1000 mg/kg showed that the differentially expressed genes (DEGs) such as NT5C2L1, pmm1, FasL and the differentially metabolites such as xanthine, dGMP, guanine and glutamate were mainly concentrated in signaling pathways such as Purine metabolism and FoxO signaling pathway. In conclusion, LBP regulates the metabolic waste levels of tilapia mainly through Purine metabolism and the FoxO signaling pathway, thereby inhibiting cell apoptosis, improving the utilization of nutrients, and promoting the growth of tilapia. This study not only provides a theoretical basis for the application of LBP in aquatic animals but also provides useful information for the healthy development of the aquaculture.

Identification of Metabolism-Related Genes Influencing Prognosis of Multiple Myeloma Patients.

Multiple myeloma (MM) is the second most commonly diagnosed hematological malignancy. Understanding the basic mechanisms of the metabolism in MM may lead to new therapies that benefit patients. We collected the gene expression profile data of GSE39754 and performed differential analysis. Furthermore, identify the candidate genes that affect the prognosis of the differentially expressed genes (DEGs) related to the metabolism. Enrichment analysis is used to identify the biological effects of candidate genes. Perform coexpression analysis on the verified DEGs. In addition, the candidate genes are used to cluster MM into different subtypes through consistent clustering. Use LASSO regression analysis to identify key genes, and use Cox regression analysis to evaluate the prognostic effects of key genes. Evaluation of immune cell infiltration in MM is by CIBERSORT. We identified 2821 DEGs, of which 348 genes were metabolic-related prognostic genes and were considered candidate genes. Enrichment analysis revealed that the candidate genes are mainly related to the proteasome, purine metabolism, and cysteine and methionine metabolism signaling pathways. According to the consensus clustering method, we identified the two subtypes of group 1 and group 2 that affect the prognosis of MM patients. Using the LASSO model, we have identified 10 key genes. The prognosis of the high-risk group identified by Cox regression analysis is worse than that of the low-risk group. Among them, PKLR has a greater impact on the prognosis of MM, and the prognosis of MM patients is poor when the expression is high. In addition, the level of immune cell infiltration in the high-risk group is higher than that in the low-risk group. In the summary, metabolism-related genes significantly affect the prognosis of MM patients through the metabolic process of MM patients. PKLR may be a prognostic risk factor for MM patients.

Transcriptome Analysis of Colletotrichum fructicola Infecting Camellia oleifera Indicates That Two Distinct Geographical Fungi Groups Have Different Destructive Proliferation Capacities Related to Purine Metabolism.

Anthracnose, caused by Colletotrichum spp., is a significant disease affecting oil tea (Camellia oleifera Abel.). Extensive molecular studies have demonstrated that Colletotrichum fructicola is the dominant pathogen of oil tea anthracnose in China. This study aims to investigate differences in molecular processes and regulatory genes at a late stage of infection of C. fructicola, to aid in understanding differences in pathogenic mechanisms of C. fructicola of different geographic populations. We compared the pathogenicity of C. fructicola from different populations (Wuzhishan, Hainan province, and Shaoyang, Hunan province) and gene expression of representative strains of the two populations before and after inoculation in oil tea using RNA sequencing. The results revealed that C. fructicola from Wuzhishan has a more vital ability to impact oil tea leaf tissue. Following infection with oil tea leaves, up-regulated genes in the strains from two geographic populations were associated with galactosidase activity, glutamine family amino acid metabolism, arginine, and proline metabolism. Additionally, up-regulated gene lists associated with infection by Wuzhishan strains were significantly enriched in purine metabolism pathways, while Shaoyang strains were not. These results indicate that more transcriptional and translational activity and the greater regulation of the purine metabolism pathway in the C. fructicola of the Wuzhishan strain might contribute to its stronger pathogenicity.

Whole genome analysis and specific PCR primer development for Vibrio coralliilyticus, combined with transcription and metabolome analysis of red spotting disease in the sea urchin, Strongylocentrotus intermedius

Vibrio coralliilyticus is a notorious pathogen that causes disease in coral. Recently, we identified a pathogenic strain of V. coralliilyticus, Rb102, from farmed sea urchins that had "red spotting disease". In this study, we performed whole genome sequencing for Rb102 and compared the sequence with ten common aquatic pathogens. A specific PCR detection method was then developed for V. coralliilyticus. In addition, disease–resistant sea urchins and those suffering from red spotting disease were sent for comparative analysis of the transcriptome and metabolome. The complete genome was found to be 5758,353 bp and contains two large chromosomes (Chr1 and Chr2) and one plasmid. The groEL gene was chosen for the design of specific PCR identification primers. Differential transcriptome analysis between diseased and disease resistant groups revealed that there are 1845 differentially expressed genes (DEGs), with the largest number enriched in the purine metabolic pathway. Significant differences were detected between the two groups in 91 cationic metabolites and 43 anionic metabolites. Deoxyinosine was the most significantly down–regulated metabolite and is found in the purine metabolic pathway. The results of this study provide an important reference and data foundation for further study of "red spotting disease" in sea urchin farms.

Decreased purine metabolite levels in cerebrospinal fluid of transgenic cerebral amyloid angiopathy rats

AbstractBackgroundCerebral amyloid angiopathy (CAA) is a major cause of intracerebral hemorrhages and contributes to cognitive decline. The currently applied modified Boston criteria fall short in detecting early‐stage disease and biomarkers to track disease progression are lacking. In the CAA Fluid Biomarker Evaluation (CAFE) study we aim to identify novel CAA‐specific biomarkers. We hypothesize that levels of metabolites in cerebrospinal fluid (CSF) are altered due to amyloid‐β deposits.MethodHigh‐resolution liquid chromatography quadrupole time‐of‐flight mass spectrometry was used to analyze metabolite levels in an untargeted fashion (Coene et al., 2018; Peters et al., 2020) in CSF derived from small‐vessel CAA transgenic (rTg‐DI) and wild‐type (WT) rats. Candidate features identified in a discovery study (n=8 WT; n=10 rTg; 6 months old) were validated in larger groups of rats including various ages (n=30 WT; n=29 rTg; 3‐6‐12 months old). Features were annotated based on accurate mass, specific retention time and semi‐quantitative intensity by comparison with reference standard compounds and online database matching.ResultOf the 48 significantly different features discovered in the pilot, 27 could be validated in the second study. Several features corresponded with reference compounds of metabolites involved in the purine metabolism pathway, which included guanosine, guanine, inosine, xanthine and hypoxanthine. All these levels were significantly decreased in all groups of the rTg rats compared to WT, some progressing with older age (Figure 1). An additional n=605 features were identified with significantly different levels between the various groups. Molecular formulas for other possible interesting features could be computed, whose metabolite identities are currently being confirmed by using standard compounds.ConclusionMetabolomics analyses of the CSF of transgenic rats shows promise in discovering novel potential biomarkers for CAA. Using a robust animal model allows us to study biomarkers along the trajectory of disease progression. Our results suggest a global down‐regulation of the purine pathway (Figure 2), a finding previously observed in early‐stage Alzheimer’s disease (Alonso‐Andrés et al., 2017).

The Impacts of Short-Term NMN Supplementation on Serum Metabolism, Fecal Microbiota, and Telomere Length in Pre-Aging Phase.

Aging is a natural process with concomitant changes in the gut microbiota and associate metabolomes. Beta-nicotinamide mononucleotide, an important NAD+ intermediate, has drawn increasing attention to retard the aging process. We probed the changes in the fecal microbiota and metabolomes of pre-aging male mice (C57BL/6, age: 16 months) following the oral short-term administration of nicotinamide mononucleotide (NMN). Considering the telomere length as a molecular gauge for aging, we measured this in the peripheral blood mononuclear cells (PBMC) of pre-aging mice and human volunteers (age: 45–60 years old). Notably, the NMN administration did not influence the body weight and feed intake significantly during the 40 days in pre-aging mice. Metabolomics suggested 266 upregulated and 58 downregulated serum metabolites. We identified 34 potential biomarkers linked with the nicotinamide, purine, and proline metabolism pathways. Nicotinamide mononucleotide significantly reduced the fecal bacterial diversity (p < 0.05) with the increased abundance of Helicobacter, Mucispirillum, and Faecalibacterium, and lowered Akkermansia abundance associated with nicotinamide metabolism. We propose that this reshaped microbiota considerably lowered the predicated functions of aging with improved immune and cofactors/vitamin metabolism. Most notably, the telomere length of PBMC was significantly elongated in the NMN-administered mice and humans. Taken together, these findings suggest that oral NMN supplementation in the pre-aging stage might be an effective strategy to retard aging. We recommend further studies to unravel the underlying molecular mechanisms and comprehensive clinical trials to validate the effects of NMN on aging.

Ribosome Profiling and RNA Sequencing Reveal Genome-Wide Cellular Translation and Transcription Regulation Under Osmotic Stress in Lactobacillus rhamnosus ATCC 53103.

To determine whether osmotic pressure affects the translation efficiency of Lactobacillus rhamnosus, the ribosome profiling assay was performed to analyze the changes in translation efficiency in L. rhamnosus ATCC 53103. Under osmotic stress, differentially expressed genes (DEGs) involved in fatty acid biosynthesis and metabolism, ribosome, and purine metabolism pathways were co-regulated with consistent expression direction at translation and transcription levels. DEGs involved in the biosynthesis of phenylalanine, tyrosine, and tryptophan, and the phosphotransferase system pathways also were co-regulated at translation and transcription levels, while they showed opposite expression direction at two levels. Moreover, DEGs involved in the two-component system, amino acid metabolism, and pyruvate metabolism pathways were only regulated at the transcription level. And DEGs involved in fructose and mannose metabolism were only regulated at the translation level. The translation efficiency of DEGs involved in the biosynthesis of amino acids was downregulated while in quorum sensing and PTS pathways was upregulated. In addition, the ribosome footprints accumulated in open reading frame regions resulted in impaired translation initiation and elongation under osmotic stress. In summary, L. rhamnosus ATCC 53103 could respond to osmotic stress by translation regulation and control the balance between survival and growth of cells by transcription and translation.

Hfq Regulates Efflux Pump Expression and Purine Metabolic Pathway to Increase Trimethoprim Resistance in Aeromonas veronii.

Aeromonas veronii (A. veronii) is a zoonotic pathogen. It causes clinically a variety of diseases such as dysentery, bacteremia, and meningitis, and brings huge losses to aquaculture. A. veronii has been documented as a multiple antibiotic resistant bacterium. Hfq (host factor for RNA bacteriophage Qβ replication) participates in the regulations of the virulence, adhesion, and nitrogen fixation, effecting on the growth, metabolism synthesis and stress resistance in bacteria. The deletion of hfq gene in A. veronii showed more sensitivity to trimethoprim, accompanying by the upregulations of purine metabolic genes and downregulations of efflux pump genes by transcriptomic data analysis. Coherently, the complementation of efflux pump-related genes acrA and acrB recovered the trimethoprim resistance in Δhfq. Besides, the accumulations of adenosine and guanosine were increased in Δhfq in metabonomic data. The strain Δhfq conferred more sensitive to trimethoprim after appending 1 mM guanosine to M9 medium, while wild type was not altered. These results demonstrated that Hfq mediated trimethoprim resistance by elevating efflux pump expression and degrading adenosine, and guanosine metabolites. Collectively, Hfq is a potential target to tackle trimethoprim resistance in A. veronii infection.