Amino Acid Metabolic Pathways Research Articles

Therapeutic targets for hepatocellular carcinoma identified using proteomics and Mendelian randomization.

Hepatocellular carcinoma (HCC) emerges as a formidable malignancy marked by elevated morbidity and mortality rates, coupled with a dismal prognosis. The revelation of gene-protein associations has presented an avenue for the exploration of novel therapeutic targets. Pooling plasma proteomic data (seven published GWAS) and HCC data (DeCODE cohort), we applied MR to identify potential drug targets, which were further validated in the FinnGen cohort and UK Biobank. Subsequent colocalization and summary-data-based Mendelian randomization analyses were performed for potential associations of this set of proteins. In addition, enrichment information pathways were investigated in depth by KEGG pathway analysis, single-cell sequencing, PPI and DGIdb, ChEMBL, and DrugBank database analyses, specific cell types enriched for expression were identified, interacting proteins were identified, and finally, druggability was assessed. In summary, the levels of 10 proteins are linked to HCC risk. Elevated levels of TFPI2 as well as decreased levels of ALDH1A1, KRT18, ADAMTS13, TIMD4, SCLY, HRSP12, TNFAIP6, FTCD, and DDC are associated with increased HCC risk. Notably, HRSP12 show the strongest evidence. These genes are primarily expressed in specific cell types within the HCC TME. Moreover, intricate protein-protein interactions, involving key players like ALDH1A1 and RIDA, ALDH1A1 and DDC, and ALDH1A1 and KRT18, contribute significantly to the amino acid metabolism and dopaminergic neurogenesis pathway. Proteins such as ALDH1A1, KRT18, TFPI2, and DDC are promising targets for HCC therapy and broader cancer drug development. Targeting these proteins offers substantial potential in advancing HCC treatment strategies. This research delineates 10 protein biomarkers linked to HCC risk and offers novel perspectives on its etiology, as well as promising avenues for the screening of HCC protein markers and therapeutic agents.

LC-MS metabolomics uncovers potential biomarkers of semen cryo-injury in goats.

Semen cryopreservation acts a crucial role in enhancing breed improvement and conserving genetic resources. However, it often leads to decreased sperm activity and reduced pregnancy rates. Despite significant advancements in semen freezing techniques for goats, the precise factors and mechanisms causing cryo-injury remain unclear. In this study, we examined the motility characteristics of fresh semen versus frozen-thawed semen and investigated changes in the metabolite profiles of seminal plasma using liquid chromatograph-mass spectrometry (LC-MS). A total of 364 differentially expressed metabolites (DEMs) were identified between fresh and frozen-thawed semen samples. Among these, 185 metabolites were significantly up-regulated, while 179 were down-regulated (p<0.05). The majority of these DEMs belonged to lipids and lipid-like molecules, as well as organic acids and derivatives. The Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated that these DEMs were primarily involved in pathways related to amino acid synthesis and metabolism. Additionally, metabolite set enrichment analysis (MSEA) underscored the critical role of amino acid synthesis and metabolic pathways in semen cryopreservation. Specific metabolites such as alanine, proline, phenylalanine, tryptophan, tyrosine, adenosine, citric acid, flavin adenine dinucleotide (FAD), and choline emerged as potential biomarkers for sperm cryo-injury in goats. These findings provide valuable insights into enhancing the quality of semen cryopreservation in goats, contributing to improved breeding and genetic resource conservation efforts.

ApCarE4 and ApPOD3 participate in the adaptation of pea aphids to different alfalfa varieties

The adaptability of insects to hosts has long been a focal point in the study of insect-plant interactions. The pea aphid (Acythosiphon pisum), a significant pest of numerous leguminous crops, not only inflicts direct economic losses but also disseminates various plant viruses. To understand how pea aphids adapt to diverse alfalfa varieties. We analyzed the differentially expressed genes (DEGs) of pea aphids in distinct alfalfa varieties using transcriptome sequencing, and subsequently conducted functional validation of these genes. Comparative analysis between pea aphids feeding on susceptible and resistant strains revealed that DEGs in aphids feeding on resistant strains were primarily associated with transcriptional enrichment in the sugar, amino acid, protein, and lipid metabolism pathways. Fourteen DEGs related to adaptation of the pea aphid to alfalfa were chosen, including five carboxylesterases (CarE), four cytochrome P450s, three glutathione S-transferases, and two peroxidases (POD). RT-qPCR results indicated significant up-regulation of two carboxylesterase genes and two peroxidase genes after 24 h of feeding resistant alfalfa (Gannong 5, GN5) compared to the susceptible varieties (Hunter River, LRH), particularly highlighting the high expression levels of ApCarE4 and ApPOD3. Simultaneously, RNAi-induced knockdown of ApCarE4 and ApPOD3 led to a higher mortality of pea aphids in the alfalfa Hunter River. These results indicate that ApPOD3 and ApCarE4 are involved in the detoxification of metabolic functions in the adaptation of pea aphids to host switching. These findings contribute to the understanding of pea aphid adaptation to host plants and lay a foundation for further exploration of the physiological roles of carboxylesterase and peroxidase genes in pea aphids.

Comparative metabolomics reveals the mechanism for the high GA4 production in Gibberella fujikuroi CGMCC 17793

With unique advantages, gibberellin GA4 has broad application prospects. To explore the regulatory mechanism for the biosynthesis of GA4, we combined liquid chromatography-mass spectrometry (LC-MS)-based metabolomics with principal component analysis (principal component analysis, PCA) and partial least squares-discriminant analysis (PLS-DA) to screen and identify the differential metabolites between the GA4-producing strains S (industrial high-yield strain CGMCC 17793) and wild-type strain Y (NRRL 13620) of Gibberella fujikuroi fermented for the same time and the differential metabolites of strain S fermented for different time periods. KEGG and MBROLE 2.0 were used to analyze the metabolic pathways involving the differential metabolites. The results showed that compared with strain Y, strain S significantly upregulated and downregulated 107 and 66, 136 and 47, and 94 and 65 metabolites on days 3, 6, and 9, respectively. Compared with that on day 3 of fermentation, strain S upregulated 29 metabolites and downregulated 40 metabolites on day 6 and upregulated 52 metabolites and downregulated 67 metabolites on day 9. The differential metabolites between strain S and strain Y after fermentation for the same time were mainly enriched in amino acid metabolism, tricarboxylic acid (TCA) cycle, and terpenoid biosynthesis. The differential metabolites of strain S after fermentation for different time periods were mainly enriched in amino acid and sugar metabolism pathways. Pathway annotation results indicated that strain S increased the production of acetyl-CoA by promoting amino acid and sugar metabolism and TCA cycle, thereby enhancing the mevalonic acid pathway and increasing the content of isopentenyl pyrophosphate (IPP), a precursor for the synthesis of terpenoids, which ultimately led to increased GA4 production. This study explored the metabolic rules of Gibberella fujikuroi GA4, providing a theoretical basis for regulating Gibberella fujikuroi to improve GA4 production.

Elevated CO2 enhances growth and cyanide assimilation in nitrogen-deficient rice: A transcriptome and metabolomic perspective

Plants face multiple challenges from environmental pollutants and higher emissions of atmospheric CO2. Therefore, a hydroponic-based experiment was used to explore the combined effects of elevated [CO2] (700 ppm) and exogenous cyanide (CN−) (3.0 mg CN/L) on rice seedlings under nitrogen deficiency, utilizing metabonomic and transcriptomic analysis. Elevated [CO2] significantly improved the growth of CN−-treated rice seedlings compared to those with ambient [CO2] (350 ppm), and it also significantly affected CN− assimilation. Transcriptome analysis revealed distinct impacts on differentially expressed genes (DEGs) across treatments and tissues. KEGG analysis showed variability in DEGs enriched in amino acid (AA) and energy metabolism pathways due to elevated [CO2] and CN−. Metabonomic indicated that higher input of [CO2] and exogenous CN− more severely impacted energy metabolism elements than the individual species of AAs. Positive synergistic effects of elevated [CO2] and CN− were observed for glutamine and asparagine in shoots, and methionine in roots, wherein negative effects were noted for phenylalanine in shoots, and phenylalanine, valine, and alanine in roots. Meanwhile, positive effects on fumarate in shoots and α-ketoglutarate and succinate in roots were also found. Overall, elevated [CO2] enhanced growth in CN−-treated rice seedlings under nitrogen deficiency by altering AA and energy metabolism. This is the first attempt to provide new evidence of [CO2]-based gaseous fertilization as an energy-saving strategy for rice plants fed with biodegradable N-containing pollutants as a supporting N source under N deficient conditions.

Targeting Ferroptosis: Small-molecule Inducers as Novel Anticancer Agents.

Ferroptosis, a distinct form of regulated cell death characterized by iron-dependent lipid peroxidation and reactive oxygen species (ROS) accumulation, is increasingly recognized for its role in cancer development and as a potential therapeutic target. This review consolidates insights into the molecular mechanisms underpinning ferroptosis and evaluates the therapeutic potential of small-molecule inducers, such as erastin, RSL3, sulfasalazine, and sorafenib, which selectively trigger ferroptosis in cancer cells. It highlights the distinct morphological and molecular signatures of ferroptosis, its complex interplay with iron, lipid, and amino acid metabolic pathways, and the resultant implications for cancer treatment strategies. Strategic manipulation of the ferroptosis pathway offers a groundbreaking approach to cancer treatment, potentially circumventing the resistance that cancers develop against traditional apoptosis-inducing agents. Furthermore, it also emphasizes the necessity of refining these small molecules for clinical application and exploring their synergistic potential when combined with current therapies to augment overall treatment efficacy and improve patient outcomes. Ferroptosis thus emerges as a promising avenue in the realm of cancer therapy. Moving forward, research endeavors should focus on a more nuanced understanding of the interconnections between ferroptosis and other cell death modalities. Additionally, comprehensive evaluations of the long-term safety and therapeutic indices of the involved compounds are imperative. Such investigations are poised to herald a transformative shift in the paradigm of oncology, paving the way for innovative and targeted interventions.

Titanium exposure and gestational diabetes mellitus: associations and potential mediation by perturbation of amino acids in early pregnancy

BackgroundSeveral recent studies reported the potential adverse effects of titanium exposure on glucose homeostasis among the non-pregnant population, but the association of titanium exposure with gestational diabetes mellitus (GDM) is scarce.MethodsThe present study of 1,449 pregnant women was conducted within the Jiangsu Birth Cohort (JBC) study in China. Urine samples were collected in the early pregnancy, and urinary titanium concentration and non-targeted metabolomics were measured. Poisson regression estimated the association of titanium exposure in the early pregnancy with subsequent risk of GDM. Multiple linear regression screened for titanium-related urine metabolites. Mediation analyses assessed the mediating effects of candidate metabolites and pathways.ResultsAs parameterized in tertiles, titanium showed positive dose–response relationship with GDM risk (P for trend = 0.008), with women at the highest tertile of titanium exposure having 30% increased risk of GDM [relative risk (RR) = 1.30 (95% CI: 1.06, 1.61)] when compared to those exposure at the first tertile level. Meanwhile, we identified the titanium-related metabolites involved in four amino acid metabolic pathways. Notably, the perturbation of the aminoacyl-tRNA biosynthesis and alanine, aspartate and glutamate metabolism mediated 27.1% and 31.0%, respectively, of the relative effect of titanium exposure on GDM. Specifically, three titanium-related metabolites, choline, creatine and L-alanine, demonstrated predominant mediation effects on the association between titanium exposure and GDM risk.ConclusionsIn this prospective study, we uniquely identified a correlation between early pregnancy titanium exposure and increased GDM risk. We unveiled novel insights into how perturbations in amino acid metabolism may mediate the link between titanium exposure and GDM. Notably, choline, creatine, and L-alanine emerged as key mediators influencing this association. Our findings imply that elevated titanium exposure in early pregnancy can lead to amino acid dysmetabolism, thereby elevating GDM risk.Graphical

Electron-Transferring Flavoprotein and Its Dehydrogenase Required for Fungal Pathogenicity in Arthrobotrys oligospora.

Electron transfer flavoprotein (ETF) plays an important function in fatty acid beta oxidation and the amino acid metabolic pathway. It can provide pathogenicity to some opportunistic fungi via modulating cellular metabolite composition. Arthrobotrys oligospora is a typical invasion fungus to nematodes. Its ETF characterization is still unknown. Here, we showed that the mutations of A. oligospora ETF (Aoetfα and Aoetfβ) and its dehydrogenase (Aoetfdh) led to severe defects in mitochondrial integrity and blocked fatty acid metabolism. The pathogenicity-associated trap structures were completely suppressed when exposed to nematode-derived ascarosides and nutrition signals, including ammonia and urea. Compared to the wild-type strain, the nematode predatory activity was significantly reduced and delayed. But surprisingly, the rich nutrition could restore the massive trap and robust predatory activity in the mutant Aoetfβ beyond all induction cues. Moreover, the deletion of Aoetfβ has led to the accumulation of butyrate-like smell, which has a strong attraction to Caenorhabditis elegans nematodes. Ultimately, ETF and its dehydrogenase play a crucial role in nematode-trapping fungi, highlighting mitochondrial metabolite fluctuations that are connected to pathogenesis and further regulating the interactions between fungi and nematodes.

Detrimental effects of glyphosate on muscle metabolism in grass carp (Ctenopharyngodon idellus)

Glyphosate, a commonly used herbicide, has been associated with environmental pollution and potential health risks to aquatic organisms. This study investigated the effects of glyphosate on the muscle metabolism of grass carp (Ctenopharyngodon idellus) following exposure to environmentally relevant concentrations. Over a 14-day exposure period to varying glyphosate levels, significant disruptions were observed in antioxidant capacity and muscle health. These disruptions were evidenced by reductions in total antioxidant capacity (T-AOC), increases in malondialdehyde (MDA) levels, and decreases in activities of glutathione peroxidase (GSH-PX) and catalase (CAT). Furthermore, exposure to glyphosate resulted in a reduction of vitamin E content and an elevation of hormonal levels, suggesting the potential for endocrine disruption. Metabolomics analysis identified 605 distinct metabolites, with notable alterations in amino acid, carbohydrate, and nucleotide metabolism pathways. Specifically, arginine and glutathione metabolisms were severely impacted, with decreases in key amino acids such as glycine and glutathione at higher glyphosate concentrations. Nucleotide metabolism, particularly purine synthesis, was also significantly affected, with reduced levels of deoxyguanosine and other purine-related compounds. The study further investigated the origins of these differential metabolites using the MetOrigin platform, suggesting a potential involvement of the intestinal microbiota in the metabolic response to glyphosate. These findings highlight the multifaceted adverse effects of glyphosate on fish muscle, including oxidative stress and metabolic dysregulation, which may contribute to diminished muscle quality and health risks for aquatic organisms.

Gut Microbiome and Metabolome Alterations in Overweight or Obese Adult Population after Weight-Loss Bifidobacterium breve BBr60 Intervention: A Randomized Controlled Trial.

Probiotics, known for regulating gut microbiota, may aid those with overweight or obesity, but their mechanisms require more research. This study involved 75 overweight or obese young adults, randomly assigned to either a Bifidobacterium breve BBr60 (BBr60) group or a placebo group. Both groups received diet guidance and took either BBr60 (1 × 1010 CFU/day) or a placebo for 12 weeks. Researchers analyzed body composition, serum glucose, lipids, liver and kidney function, comprehensive metabolome, and intestinal homeostasis before and after the intervention. After 12 weeks, BBr60 significantly reduced weight and BMI compared to pretreatment levels and outperformed the placebo. The BBr60 group also showed improved blood biochemistry, with notably lower fasting blood glucose (FBG) levels than the placebo group (p < 0.05). Additionally, BBr60 influenced vital serum and fecal metabolites related to three amino acid metabolic pathways and regulated the bacteria Dialister, Klebsiella, and Bacteroides, which correlated strongly with serum metabolites. These findings indicate that BBr60 can safely and effectively regulate BMI, body weight, serum glucose, lipids, and liver function markers, which may involve BBr60's impact on key gut bacteria, which influence metabolites related to the valine, leucine, and isoleucine biosynthesis; glycine, serine, and threonine metabolism; and alanine, aspartate, and glutamate metabolism.

Transcriptomic profiling reveals the effect of amino acid metabolism on the production capacity of Volvariella volvacea during repeated subculture

Tissue separation is commonly employed for the purification and rejuvenation of edible mushroom species. However, repeated or continuous tissue separation can result in strain degradation. In this study, cultivation experiments were conducted in Volvariella volvacea V844 (T0). Tissue separation subculture was repeated 16 times to obtain the succession strains T1–T16. Of these, T4, T8, T12, and T16 were selected as experimental strains, and their production traits were evaluated. Additionally, transcriptome sequencing technology was used to analyze the transcription spectrum of these strains. The results showed that with the increase in subculture cycles, the colony diameter, mycelial growth rate, mycelial biomass, and biological efficiency of V. volvacea first increased and then decreased, and the growth cycle was gradually prolonged. Transcriptome sequencing revealed the presence of 1375, 1015, 651, and 1648 differentially expressed genes (DEGs) in T4, T8, T12, and T16, respectively, versus T0. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis demonstrated that these DEGs were mainly involved in amino acid metabolic pathways. Further annotation analysis revealed that in V. volvacea subculture strains, the number of DEGs involved in histidine metabolism (Ko00340) and arginine and proline metabolism (Ko00330) was the highest. Amino acid analysis demonstrated that the proline and arginine content first rose and then fell across successive subculture strains, whereas the histidine content first decreased and then increased. The results indicated that the change in the production capacity of V. volvacea during repeated subculture may be due to the altered expression of DEGs involved in amino acid metabolism, leading to changes in the amino acid content of V. volvacea and further affecting the accumulation of reactive oxygen species, free radical scavenging, energy acquisition, nutrient absorption, and redox balance. These changes could result in the rejuvenation (<8) of the V. volvacea strain or cause its degradation (>12). The results of this study provide a theoretical framework for studying the mechanisms of rejuvenation and degradation in V. volvacea and also offer insights valuable for studying the molecular functions of genes involved in the growth of V. volvacea and other edible fungi.

Branched-chain amino acids modulate the proteomic profile of Trypanosoma cruzi metacyclogenesis induced by proline.

Trypanosoma cruzi, the causative agent of Chagas disease, has a complex life cycle that involves triatomine insects as vectors and mammals as hosts. The differentiation of epimastigote forms into metacyclic trypomastigotes within the insect vector is crucial for the parasite's life cycle progression. Factors influencing this process, including temperature, pH, and nutritional stress, along with specific metabolite availability, play a pivotal role. Amino acids like proline, histidine, and glutamine support cell differentiation, while branched-chain amino acids (BCAAs) inhibit it. Interestingly, combining the pro-metacyclogenic amino acid proline with one of the anti-metacyclogenic BCAAs results in viable metacyclics with significantly reduced infectivity. To explore the characteristics of metacyclic parasites differentiated in the presence of BCAAs, proteomics analyses were conducted. Metacyclics obtained in triatomine artificial urine (TAU) supplemented with proline alone and in combination with leucine, isoleucine, or valine were compared. The analyses revealed differential regulation of 40 proteins in TAU-Pro-Leu, 131 in TAU-Pro-Ile, and 179 in TAU-Pro-Val, as compared to metacyclics from TAU-Pro. Among these, 22%, 11%, and 13% of the proteins were associated with metabolic processes, respectively. Notably, enzymes related to glycolysis and the tricarboxylic acid (TCA) cycle were reduced in metacyclics with Pro-BCAAs, while enzymes involved in amino acid and purine metabolic pathways were increased. Furthermore, metacyclics with Pro-Ile and Pro-Val exhibited elevated enzymes linked to lipid and redox metabolism. The results revealed five proteins that were increased and four that were decreased in common in the presence of Pro+BCAAs, indicating their possible participation in key processes related to metacyclogenesis. These findings suggest that the presence of BCAAs can reshape the metabolism of metacyclics, contributing to the observed reduction in infectivity in these parasites.

Early changes in the gut microbiome among HIV-infected Individuals in Uganda initiating daily TMP/SMX.

Daily cotrimoxazole (TMP/SXT) prophylaxis is part of the HIV treatment package for all new HIV-infected individuals in Uganda. Although this treatment has shown reduced morbidity and mortality in HIV, it remains controversial due to its contribution to developing antibiotic-resistant bacteria. Moreover, the effects of daily use of a broad-spectrum antibiotic on the gut microbiome remain unknown. To study the early effects, we analysed shotgun metagenome sequence data from stool samples of five newly HIV-infected individuals initiating TMP/SXT prophylaxis longitudinally for the first 30 days of treatment. Using shotgun metagenomics sequencing, we generated both taxonomic and functional profiles from each patient and compared gut microbial changes Pre-TMP/SXT and post-TMP/SXT on Day 5, Day 14, and Day 30. Daily TMP/SXT prophylaxis resulted in a shift characterised by an enrichment of Prevetollea and Ruminococcus genera members and the depletion of Lactococcus and Bacteroides genera members. Furthermore, these microbial shifts were associated with changes in the functional profile revealed by a differential abundance of pathways of amino acid metabolism, carbohydrate metabolism, and nucleotide biosynthesis linked to members of the Bacteroidaceae and Enterobacteriaceae families. TMP/SXT daily prophylaxis in HIV-infected individuals is associated with dramatic changes in microbial composition and functional profiles; however, other factors such as Age, Gender, HIV clinical stage, and ART regiment are at play. Further investigation is needed to examine the implication of these shifts on clinical management and outcomes among HIV patients.

6870 Cardiac Imaging And Metabolomics Studies Suggest Differential Risk And Protective Biomarkers For Cardiovascular Disease In Renoprotected, Long-Duration Type 1 Diabetes

Abstract Disclosure: M. Yu: None. S. Jangolla: None. N. Ziemniak: None. E. Viebranz: None. T. Chokshi: None. K. Park: None. I. Wu: None. H. Shah: None. G.L. King: None. Cardiovascular disease (CVD) is a major cause of mortality in people with Type 1 diabetes (T1D), especially in those with nephropathy (DN). However, in long-duration T1D, a substantial proportion of individuals without DN still exhibit excessive CVD risks. The Joslin 50-Year “Medalist” Study (n=1043), composed of people with T1D≥50 years, are ideal for studying CVD in a renoprotected T1D cohort, as only 13% have DN, and yet 40% have CVD, despite excellent control of lipids and blood pressure. Stratifying the Medalists by DN revealed that exercise was cardioprotective in the group with DN (OR 0.60, p=0.04); while age at T1D diagnosis (OR 1.03, p=0.01), HbA1c (OR 1.25, p=0.01), C-reactive protein (OR 1.14, p=0.01), and interleukin-6 (OR 1.13, p=0.01) all increased CVD risk in Medalists without DN. A subset of Medalists also underwent coronary artery calcification scans (CAC; n=153) and cardiac magnetic resonance imaging of left ventricular (LV) structure and function (CMR; n=111). The majority of these Medalists (97.8%) had detectable CAC&amp;gt;0; furthermore, the median CAC score of 1000 was higher at any cutoff compared to similar age-matched T1D and Type 2 diabetes (T2D) populations with higher DN prevalence. In contrast, mean CMR values in this Medalist subset were comparable to other cohorts. Continuous glucose monitoring (CGM) metrics for hyperglycemia (mean glucose, β=0.002, p=0.03; glucose management indicator, β=0.09, p=0.03; and time above range&amp;gt;180 mg/dL, β=0.003, p=0.02), but not glucose variability or hypoglycemia, were associated with LV remodeling in the Medalists, even after adjusting for eGFR. Likewise, plasma levels of advanced glycation end-products (AGEs) N-carboxyethyl-lysine (CEL), N-carboxymethyl-lysine (CML), and methylglyoxal-derived hydroimidazolone (MGH1) were associated with CAC (β=16.22, p=0.05; β=15.21, p=0.01; and β=10.18, p=0.01, respectively) and LV remodeling (β=0.001, p=0.09; β=0.001, p=0.05; and β=0.001, p=0.04, respectively) in the Medalists. The association of CEL with CVD replicated in a separate Medalist subset (n=311) with self-reported CVD data (OR 1.26, p=0.01). Plasma global metabolomics studies (n=140) revealed that amino acid activation pathways, with lower levels of branched chain amino acids, were associated with CAC (FDR=0.002); while amino acid metabolism pathways were associated with less favorable LV volumes (FDR=0.03). In this comprehensive study of aging T1D people with no substantial DN, hyperlipidemia, or hypertension, cardiac imaging and metabolomics studies suggest disproportionate advanced CAC, as compared to subclinical LV remodeling or dysfunction, and highlight the importance of targeting hyperglycemia for CVD risk reduction. Plasma metabolites associated with CVD in T1D are different from those in T2D, and may provide novel information on potential therapeutic targets for CVD in T1D. Presentation: 6/1/2024

Quercetin microgels alter gut metabolome and reverse oxidative damage invitro

Colonic delivery of quercetin using encapsulation techniques is an effective approach in maximizing quercetin efficacy against oxidative-stress related diseases such as inflammatory bowel disease. We hypothesized that colon-targeted delivery of quercetin with quercetin loaded alginate-chitosan microgels (ALQ) could alter colonic microbial metabolism regulating microbial metabolites production that may exert biological effects at the cellular level. To demonstrate this, ALQ were subjected to colonic fermentation using human fecal microbiota with empty microgels (AL) as control, and fermented fecal samples were collected at 0, 8, and 24 h. Short chain fatty acid analysis using gas chromatography showed that ALQ increased productions of acetic acid, while decreased isobutyric and isovaleric acid production. Semi-targeted metabolome scanning using Orbitrap mass spectrometer showed that the overall metabolome profile was remarkably different between AL and ALQ treatments at both 8 h and 24 h of fermentation. There were 9 metabolites at 8 h, and 54 metabolites at 24 h that were significantly regulated with more than 2-fold changes between AL and ALQ treatments. The metabolites included quercetin derived metabolites, amino acids and their derivatives, nucleotide derivatives, and organic acids. ALQ significantly modulated tyrosine metabolism, amino acids metabolic pathways, and the tricarboxylic acid cycle. These ALQ modulated metabolites in turn protected the Caco-2 cells from lipopolysaccharides induced injury, increased cellular antioxidant activities, and alleviated lipid oxidation induced by H2O2. Conclusively, ALQ could alter human fecal metabolome in vitro with significant shifts in key metabolites and exert antioxidant effects on cellular level, exhibiting potentials in colonic disease management.

Dietary supplementary with ellagic acid improves the intestinal barrier function and flora structure of broiler chicken challenged with E. coli K88

Ellagic acid (EA) contributes to the immunity and anti-oxidant function of body, whereas there are few reports about its effect on the intestinal health and growth performance of broiler chickens. Hence, the present study was arranged to investigate the effect of dietary supplementary with EA on the intestinal barrier function and flora structure of broiler chickens challenged with Escherichia coli K88 (E. coli K88). A total of 216 healthy 1-day-old, Ross 308 broilers with uniform weight were randomly assigned into three treatment groups, six replicates in each group and twelve birds in each replicate. Broilers in the control (CTR) group and E. coli K88 infected group (ETEC) were fed with the basic diet, and 200 mg/kg EA was supplemented into the diet of the E. coli K88 infected group treated with EA (EAETEC). The animal trial had lasted for 42 days, and the outcomes showed that the ADG and ADFI during the animal trial, the jejunal villi height (VH) and the ratio of VH to crypt depth (CD) tended to be decreased with E. coli K88 treated (P< 0.05). Additionally, the level of serum diamine oxidase (DAO) and intestinal malondialdehyde (MDA) were elevated, the activity of intestinal total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), the mRNA levels in jejunal claudin-1 and occludin were down-regulated with E. coli K88 treated as well as the transcription levels of ileal Mucin-2, aquaporin-3 (AQP-3) and Na+/H+ exchanger proteins-3 (NHE-3) (P< 0.05). In addition, E. coli K88 down-regulated the α-diversity index of cecal flora, the ratio of Bacteroidota to Firmicutes and the relative abundance of Barnesiella were up-regulated and it of Alistipes was descended with E. coli K88 treated (P< 0.05). Beyond that, the content of propionic acid in the cecal chyme was decreased and the amino acid metabolic pathways were inhibited with E. coli K88 challenged (P< 0.05). Additionally, there was a significant positive correlation between the relative abundance of Alistipes and the levels of butyric acid in the caecal chyme and the activity of GSH-Px in the intestine (P< 0.05). Interestingly, dietary supplementary with EA could reshape the intestinal flora structure and alleviate the above negative effects of E. coli K88 on broiler chickens. In conclusion, dietary supplementary with ellagic acid improved the intestinal barrier function and flora structure of broiler chickens challenged with E. coli K88.

Limosilactobacillus fermentum CGMCC 1.7434 and Debaryomyces hansenii GDMCC 2.149 synergize with ultrasound treatment to efficiently degrade nitrite in air-dried ducks

Nitrites in meat products are important food additives with coloring, antibacterial and antioxidant effects, but excessive intake of nitrites can pose health risks, including an increased risk of cancer due to the formation of carcinogenic nitrosamines. In the present study, Limosilactobacillus fermentum CGMCC 1.7434 was screened and the effects of it and Debaryomyces hansenii GDMCC 2.149 and their combination on nitrite degradation were investigated. It was found that the co-culture of L. fermentum CGMCC 1.7434 and D. hansenii GDMCC 2.149 significantly enhanced nitrite degradation (99.58%). The findings on salt and ethanol tolerance suggest suitability for application in meat fermentation processes. Scanning electron microscopy and additional data indicate that D. hansenii GDMCC 2.149 facilitates the growth, acid production, adhesion, secretion of AI-2 signaling molecules, and biofilm formation of L. fermentum CGMCC 1.7434. Metabolomics analysis suggests that these microorganisms reduce nitrite levels by converting NH3 derived from nitrite into L-glutamine, which is further transformed into N-nitroso compounds and their downstream derivatives through the ABC transporter pathway, the TCA cycle, and the amino acid metabolism pathway. Microbial community analyses showed that L. fermentum CGMCC 1.7434 and D. hansenii GDMCC 2.149 were successfully inoculated into air-dried ducks, becoming dominant strains and effectively inhibiting the growth of pathogenic bacteria. Furthermore, during the processing of air-dried duck, the combination of ultrasonic cavitation (250 W, 4 min, 30°C, 40 kHz) with the co-fermentation of L. fermentum CGMCC 1.7434 and D. hansenii GDMCC 2.149 effectively reduced nitrite content (84.55%) and TVB-N levels in the meat, without compromising color or TBARS values. This is crucial for understanding the mechanism of nitrite degradation by LAB in synergy with yeast and for the advancement of low-nitrite air-dried duck products.

Colonization profiles of gut microbiota in goat kids from neonatal to weaning period.

Understanding the colonization and change patterns of gut microbiota is pivotal for comprehending host health. As a newly cultured breed, the studies on the gut microbiota of Tianfu goats remain limited. This study aimed to address this gap by analyzing the microbial composition and colonization patterns of fecal samples collected from goat kids from birth to weaning. Fecal samples were collected on days 0, 7, 14, 21, 28, 35, 42, 49, 53, 55, 57, and 64, and the changes and colonization patterns of microorganisms were analyzed through high-throughput 16S rRNA sequencing. The results showed that the abundance of fecal microbiota in goat kids gradually increased over time, followed by a decrease after weaning and stabilization, with reduced individual differences. The colonization of fecal microorganisms mainly presented three different stages: days 0-14, days 21-49, and days 53-64. During the suckling period, the relative abundance of Proteobacteria (72.34%) was the highest, followed by Firmicutes (21.66%). From 21 days old, the microbiota in goat kids gradually to be diverse, with Lachnospiraceae and Ruminococcaceae being dominant. During post-weaning, Ruminococcaceae (30.98-33.34%) was becoming prominence which helpful for cellulose decomposition. LEfSe analyzed three important time points (d0 vs. d7, d7 vs. d14, d49 vs. d53, LDA score > 4 and p < 0.05), 53 microbial communities with stage differences were identified. Functional prediction using PICRUSt revealed that differential microbial communities are mainly related to carbohydrate and amino acid metabolism pathways. Overall, this study addresses the intricate relationship between ages, diets, and microbiota compositions in Tianfu goat kids, and also offering insights into microorganisms-host interactions.

Rewiring the nexus between urban traffic pollution-derived polycyclic aromatic hydrocarbon exposure and DNA injury via urinary metabolomics.

Urban road traffic environmental stress impacts outdoor population health, with oxidative damage serving as an early indicator of xenobiotic exposure. Polycyclic aromatic hydrocarbons (PAHs) as priority carcinogens pose significant public health burden, yet knowledge remains limited regarding the endogenous metabolic alternations associated with oxidative DNA injury. This cross-sectional study focused on the cohort consisting of 109 sanitation workers ("traffic exposure group") and 112 demographics-matched common residents ("controls") in South China. The goal was to elucidate the occurrence of internal exposure to nine hydroxyl PAHs, and the interrelations with oxidative DNA damage (indicated by 8-hydroxy-2'-deoxyguanosine, 8-OHdG) by linear mixed-effect regression model. T-test and orthogonal partial least squares discriminant analysis were used to determine differential metabolites in non-targeted metabolomics. Results revealed outdoor workers suffered from the heavier PAH exposure burden and exhibited a stronger dose-dependent correlation with 8-OHdG, evidenced by the higher regression coefficient (0.244, 95% CI: 0.154-0.334) than controls (0.203, 95% CI: 0.079-0.328). In total 42 differential endogenous metabolites witnessed significant expression under traffic emission scenario, mainly implicated in phenylalanine, tyrosine and tryptophan biosynthesis. The down-expressed uric acid was the unique metabolite that inversely correlated with the increased intake of ∑8PAH especially in cases. Partially attributed to the traffic-derived PAHs, the dysregulated amino acid, nicotinamide, purine, and steroid hormones metabolic pathways encompassing 11 metabolites were determined as underlying biomarkers in mediating DNA damage. Notably, our findings proposed uric acid may act as a potential antioxidant, as evidenced by the negative correlation with 8-OHdG. The study illustrates outcomes of metabolomics can collaboratively indicate DNA oxidative damage caused by PAHs linked to urban traffic exposure, which holds significant implications for future toxicological research.

Gut microbiota combined with serum metabolites to reveal the effect of Morchella esculenta polysaccharides on lipid metabolism disordered in high-fat diet mice

The ameliorating effects and mechanisms of Morchella esculenta polysaccharides (MEP-1) on lipid metabolism were investigated in high-fat diet (HFD) mice. The results showed that MEP-1 intervention significantly reduced serum TC, TG, LDL-C, and inflammatory factors (TNF-α, IL-1β and IL-6) in HFD mice in a dose-dependent manner, and high-dose (400 mg/kg/d) exhibited the most significant reductive effects. In addition, MEP-1 significantly recovered the gut microbiota disorders caused by HFD, especially decreasing the ratio of Firmicutes and Bacteroidetes (F/B) and increasing the dominant bacterial of Muribaculaceae_genus, Bacteroides, Alistipes and Enterococcus. Moreover, MEP-1 promoted the production of SCFAs and increased the expression levels of Occludin, Claudin and Muc2, also regulated lipid metabolism disorder and inflammation by inhibiting TLR4/MyD88/NF-κB via the gut-liver axis. In addition, serum metabolomic analysis revealed that l-phenylalanine, l-arginine and acetylcholine were significantly upregulated with MEP-1 intervention, and were negatively correlated with blood lipid level, in which l-arginine could activate NO/PPARα/CPT1A pathway to ameliorate lipid metabolism disorders. Such results demonstrated that gut microbiota, amino acid metabolic and insulin secretion pathways might be the important factors that mediated the regulation of MEP-1 in lipid metabolism. The results also provided new evidence and strategies for the application of MEP-1 as functional foods.