This study aims to investigate the mechanism of Qingrun Decoction in alleviating hepatic insulin resistance in type 2 diabetes mellitus(T2DM) rats through the reprogramming of amino acid metabolism. A T2DM rat model was established by inducing insulin resistance through a high-fat diet combined with intraperitoneal injection of streptozotocin. The model rats were randomly divided into five groups: model group, high-, medium-, and low-dose Qingrun Decoction groups, and metformin group. A normal control group was also established. The rats in the normal and model groups received 10 mL·kg~(-1) distilled water daily by gavage. The metformin group received 150 mg·kg~(-1) metformin suspension by gavage, and the Qingrun Decoction groups received 11.2, 5.6, and 2.8 g·kg~(-1) Qingrun Decoction by gavage for 8 weeks. Blood lipid levels were measured in different groups of rats. Pathological damage in rat liver tissue was assessed by hematoxylin-eosin(HE) staining and oil red O staining. Transcriptome sequencing and untargeted metabolomics were performed on rat liver and serum samples, integrated with bioinformatics analyses. Key metabolites(branched-chain amino acids, BCAAs), amino acid transporters, amino acid metabolites, critical enzymes for amino acid metabolism, resistin, adiponectin(ADPN), and mammalian target of rapamycin(mTOR) pathway-related molecules were quantified using quantitative real-time polymerase chain reaction(qRT-PCR), Western blot, and enzyme-linked immunosorbent assay(ELISA). The results showed that compared with the normal group, the model group had significantly increased serum levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), and resistin and significantly decreased ADPN levels. Hepatocytes in the model group exhibited loose arrangement, significant lipid accumulation, fatty degeneration, and pronounced inflammatory cell infiltration. In liver tissue, the mRNA transcriptional levels of solute carrier family 7 member 2(Slc7a2), solute carrier family 38 member 2(Slc38a2), solute carrier family 38 member 4(Slc38a4), and arginase(ARG) were significantly downregulated, while the mRNA transcriptional levels of solute carrier family 1 member 4(Slc1a4), solute carrier family 16 member 1(Slc16a1), and methionine adenosyltransferase(MAT) were upregulated. Furthermore, the mRNA transcription and protein expression levels of branched-chain α-keto acid dehydrogenase E1α(BCKDHA) and DEP domain-containing mTOR-interacting protein(DEPTOR) were downregulated, while mRNA transcription and protein expression levels of mTOR, as well as ribosomal protein S6 kinase 1(S6K1), were upregulated. The levels of BCAAs and S-adenosyl-L-methionine(SAM) were elevated. The serum level of 6-hydroxymelatonin was significantly reduced, while imidazole-4-one-5-propionic acid and N-(5-phospho-D-ribosyl)anthranilic acid levels were significantly increased. Compared with the model group, Qingrun Decoction significantly reduced blood lipid and resistin levels while increasing ADPN levels. Hepatocytes had improved morphology with reduced inflammatory cells, and fatty degeneration and lipid deposition were alleviated. Differentially expressed genes and differential metabolites were mainly enriched in amino acid metabolic pathways. The expression levels of Slc7a2, Slc38a2, Slc38a4, and ARG in the liver tissue were significantly upregulated, while Slc1a4, Slc16a1, and MAT expression levels were significantly downregulated. BCKDHA and DEPTOR expression levels were upregulated, while mTOR and S6K1 expression levels were downregulated. Additionally, the levels of BCAAs and SAM were significantly decreased. The serum level of 6-hydroxymelatonin was increased, while those of imidazole-4-one-5-propionic acid and N-(5-phospho-D-ribosyl)anthranilic acid were decreased. In summary, Qingrun Decoction may improve amino acid metabolism reprogramming, inhibit mTOR pathway activation, alleviate insulin resistance in the liver, and mitigate pathological damage of liver tissue in T2DM rats by downregulating hepatic BCAAs and SAM and regulating key enzymes involved in amino acid metabolism, such as BCKDHA, ARG, and MAT, as well as amino acid metabolites and transporters.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Insulin Resistance ; Diabetes Mellitus, Type 2/genetics* ; Male ; Liver/drug effects* ; Amino Acids/metabolism* ; Rats, Sprague-Dawley ; Humans ; Metabolic Reprogramming

PURPOSE: The secondary damage of spinal cord injury (SCI) starts from the collapse of the blood spinal cord barrier (BSCB) to chronic and devastating neurological deficits. Thereby, the retention of the integrity and permeability of BSCB is well-recognized as one of the major therapies to promote functional recovery after SCI. Previous studies have demonstrated that activation of hypoxia inducible factor-1α (HIF-1α) provides anti-apoptosis and neuroprotection in SCI. Endogenous HIF-1α, rapidly degraded by prolylhydroxylase, is insufficient for promoting functional recovery. Dimethyloxalylglycine (DMOG), a highly selective inhibitor of prolylhydroxylase, has been reported to have a positive effect on axon regeneration. However, the roles and underlying mechanisms of DMOG in BSCB restoration remain unclear. Herein, we aim to investigate pathological changes of BSCB restoration in rats with SCI treated by DOMG and evaluate the therapeutic effects of DMOG. METHODS: The work was performed from 2022 to 2023. In this study, Allen's impact model and human umbilical vein endothelial cells were employed to explore the mechanism of DMOG. In the phenotypic validation experiment, the rats were randomly divided into 3 groups: sham group, SCI group, and SCI + DMOG group (10 rats for each). Histological analysis via Nissl staining, Basso-Beattie-Bresnahan scale, and footprint analysis was used to evaluate the functional recovery after SCI. Western blotting, TUNEL assay, and immunofluorescence staining were employed to exhibit levels of tight junction and adhesion junction of BSCB, HIF-1α, cell apoptosis, and endoplasmic reticulum (ER) stress. The one-way ANOVA test was used for statistical analysis. The difference was considered statistically significant at p < 0.05. RESULTS: In this study, we observed the expression of HIF-1α reduced in the SCI model. DMOG treatment remarkably augmented HIF-1α level, alleviated endothelial cells apoptosis and disruption of BSCB, and enhanced functional recovery post-SCI. Besides, the administration of DMOG offset the activation of ER stress induced by SCI, but this phenomenon was blocked by tunicamycin (an ER stress activator). Finally, we disclosed that DMOG maintained the integrity and permeability of BSCB by inhibiting ER stress, and inhibition of HIF-1α erased the protection from DMOG. CONCLUSIONS Our findings illustrate that the administration of DMOG alleviates the devastation of BSCB and HIF-1α-induced inhibition of ER stress.
Spinal Cord Injuries/pathology* ; Animals ; Apoptosis/drug effects* ; Amino Acids, Dicarboxylic/therapeutic use* ; Recovery of Function/drug effects* ; Rats ; Rats, Sprague-Dawley ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Male ; Spinal Cord/blood supply*

OBJECTIVES: To investigate the impact of prenatal fear stress on placental amino acid transport and emotion and cognition development in offspring rats. METHODS: Thirty pregnant Wistar rats were randomized equally into control and fear stress (induced using an observational foot shock model) groups. In each group, placental and serum samples were collected from 6 dams on gestational day 20, and the remaining rats delivered naturally and the offspring rats were raised under the same conditions until 8 weeks of age. Emotional and cognitive outcomes of the offspring rats were assessed with behavioral tests, and placental structure was examined using HE staining. Bioinformatics analysis was used to identify differentially expressed placental transporter genes under fear stress. The expressions of system A and system L amino acid transporters, along with other specialized transporters, were detected using qRT-PCR and Western blotting. Fetal serum amino acid concentrations were determined by HPLC. The correlations between fetal amino acid levels and behavioral outcomes of the offspring rats were analyzed. RESULTS: The dams with fear stress showed reduced open-field activity and increased freezing behavior with significantly decreased placental weight, fetal weight, and fetal-to-placental ratio. Bioinformatics analysis revealed 28 differentially expressed transporter genes involved mainly in amino acid transport. In the fear stress group, fetal serum amino acid levels were significantly lowered and Slc38a1, Slc43a1, Slc43a2, Slc7a8, Slc6a6, Slc1a1 and Slc6a9 mRNA and protein expressions were all downregulated. The offspring rats in fear stress group exhibited decreased novel object preference and spontaneous alternation with reduced open arm exploration and increased immobility in emotional tests. Lower early-life amino acid levels was found to correlate with impaired adult cognition. CONCLUSIONS Prenatal fear stress in rats impairs placental amino acid transporter expression and reduces fetal serum amino acid levels, potentially contributing to long-term cognitive deficits in the offspring rats.
Animals ; Female ; Pregnancy ; Placenta/metabolism* ; Fear ; Rats ; Rats, Wistar ; Cognition ; Prenatal Exposure Delayed Effects ; Stress, Psychological ; Amino Acids/blood* ; Amino Acid Transport Systems/metabolism*

Amino acid metabolism plays a critical role in the progression and development of breast cancer. Cancer cells, including those in breast cancer, reprogram amino acid metabolism to meet the demands of rapid proliferation, survival, and immune evasion. This includes alterations in the uptake and utilization of amino acids, such as glutamine, serine, glycine, and arginine, which provide essential building blocks for biosynthesis, energy production, and redox homeostasis. Notably, the metabolic phenotypes of breast cancer cells vary across molecular subtypes and disease stages, emphasizing the need for patient stratification and personalized therapeutic strategies. Advances in multi-level diagnostics, including phenotyping and predictive tools, such as AI-based analysis and body fluid profiling, have highlighted the potential for tailoring treatments to individual metabolic profiles. Enzymes, such as glutaminase and serine hydroxymethyltransferase, often upregulated in breast cancer, represent promising therapeutic targets. Understanding the interplay between amino acid metabolism and breast cancer biology, alongside the integration of personalized medicine approaches, can uncover novel insights into tumor progression and guide the development of precision therapies. This review explores the metabolic pathways of amino acids in breast cancer, with a focus on their implications for personalized treatment strategies.
Humans ; Breast Neoplasms/therapy* ; Female ; Amino Acids/metabolism*

Myelin-forming oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) are essential for structural and functional homeostasis of nervous tissue. Albeit with certain similarities, the regulation of CNS and PNS myelination is executed differently. Recent advances highlight the coordinated regulation of oligodendrocyte myelination by amino-acid sensing and growth factor signaling pathways. In this review, we discuss novel insights into the understanding of differential regulation of oligodendrocyte and Schwann cell biology in CNS and PNS myelination, with particular focus on the roles of growth factor-stimulated RHEB-mTORC1 and GATOR2-mediated amino-acid sensing/signaling pathways. We also discuss recent progress on the metabolic regulation of oligodendrocytes and Schwann cells and the impact of their dysfunction on neuronal function and disease.
Amino Acids ; Myelin Sheath/metabolism* ; Schwann Cells/metabolism* ; Oligodendroglia/metabolism* ; Signal Transduction ; Intercellular Signaling Peptides and Proteins/metabolism*

Branched chain amino acids, as essential amino acids, can be used to synthesize nitrogen-containing compounds and also act as signal molecules to regulate substance metabolism. Studies have shown that the elevated level of branched chain amino acids is closely related to insulin resistance and type 2 diabetes. It can affect insulin signal transduction by activating mammalian target of rapamycin (mTOR) signal pathway, and regulate insulin resistance by damaging lipid metabolism and affecting mitochondrial function. In addition, abnormal catabolism of branched amino acids can lead to the accumulation of metabolic intermediates, such as branched chain α-keto acids, 3-hydroxyisobutyrate and β-aminoisobutyric acid. Branched chain α-keto acids and 3-hydroxyisobutyrate can induce insulin resistance by affecting insulin signaling pathway and damaging lipid metabolism. β-aminoisobutyric acid can improve insulin resistance by reducing lipid accumulation and inflammatory reaction and enhancing fatty acid oxidation. This paper systematically reviewed the regulatory effects and mechanisms of branched chain amino acids and their metabolic intermediates on insulin resistance, which will provide a new direction for the prevention and treatment of insulin resistance and type 2 diabetes.
Humans ; Amino Acids, Branched-Chain/metabolism* ; Insulin Resistance/physiology* ; Diabetes Mellitus, Type 2 ; Insulin/pharmacology* ; Keto Acids/metabolism*

Objective: To investigate the clinical significance of endothelin A receptor (ETAR) expression in high-grade serous ovarian carcinoma (HGSOC). To design ETAR carboxyl terminal (ETAR-C) amino acids derived polypeptide and to study the inhibitory effect on ovarian epithelial carcinoma cells in vitro. Methods: (1) A total of 126 patients who received surgical treatment and were diagnosed with HGSOC by postoperative pathological examination in Central Hospital of Xuzhou from January 1, 2007 to December 31, 2017 were selected. All patients had completed clinicopathological data and follow-up data. Cancer tissue samples were collected and ETAR mRNA expression in HGSOC tissues was detected by reverse transcript-PCR. The clinical significance was analyzed. (2) ETAR-C fusion polypeptide was designed based on the sequence of carboxyl terminal amino acids of ETAR, expressed and purified in vitro. The effects of ETAR-C fusion polypeptide on migration and invasion ability of ovarian cancer SKOV3 and CAOV3 cells were detected by scratch test and invasion test, respectively. The effect of ETAR-C fusion polypeptide on chemosensitivity of cisplatin-resistant ovarian cancer SKOV3/cDDP and CAOV3/cDDP cells was determined by methyl thiazolyl tetrazolium (MTT) colorimetric assay. The effect of ETAR-C fusion polypeptide on β-arrestin-1 expression in ovarian cancer SKOV3 and CAOV3 cells was detected by western blot. Results: (1) The relative expression level of ETAR mRNA in HGSOC tissues was 18.6±5.1. Patients with HGSOC were divided into high ETAR mRNA expression (n=76) and low ETAR mRNA expression (n=50) with 61.7% as cut-off value analyzed by X-Tile software. High expression of ETAR mRNA was significantly correlated with abdominal water volume, platinum drug resistance, and cancer antigen 125 (CA₁₂₅) value in HGSOC patients (all P<0.05), but was not related to the age of patients with HGSOC and the size of postoperative residual lesions (all P>0.05). The 5-year progression free survival rates were 18.4% and 28.0%, and the 5-year overall survival rates were 38.2% and 52.0% in HGSOC patients with high and low ETAR mRNA expression respectively, there were statistically significant differences (P=0.046, P=0.034). (2) The results of scratch test and invasion test showed that the scratch healing rate and cell invasion rate of SKOV3 or CAOV3 cells treated with endothelin-1 (ET-1) and ET-1+ETAR-C were respectively compared, and the differences were statistically significant (all P<0.05). MTT assay showed that the inhibition rates of ETAR-C fusion polypeptide treated in SKOV3/cDDP and CAOV3/cDDP cells were significantly higher than those of control cells after the addition of 4, 6, 8, 10, 12, and 24 μg/ml cisplatin (all P<0.05). Western blot analysis showed that the relative expression levels of β-arrestin-1 in SKOV3 or CAOV3 cells treated with ET-1 and ET-1+ETAR-C were 1.85±0.09 and 1.13±0.09 (SKOV3 cells), 2.14±0.15 and 1.66±0.12 (CAOV3 cells), respectively. The differences were statistically significant (all P<0.05). Conclusions: The prognosis of HGSOC patients with high expression of ETAR mRNA is significantly worse than those with low expression of ETAR mRNA. ETAR might be a new target for HGSOC treatment. The ETAR-C fusion polypeptide that interferes with the interaction of ETAR and β-arrestin-1 has good inhibitory effect on ovarian cancer cells in vitro, and might have clinical application potential.
Female ; Humans ; Amino Acids/therapeutic use* ; beta-Arrestins/therapeutic use* ; Cell Line, Tumor ; Cisplatin/pharmacology* ; Clinical Relevance ; Ovarian Neoplasms/pathology* ; Receptor, Endothelin A/therapeutic use* ; RNA, Messenger/metabolism*

Cyclodipeptide (CDP) composed of two amino acids is the simplest cyclic peptide. These two amino acids form a typical diketopiperazine (DKP) ring by linking each other with peptide bonds. This characteristic stable ring skeleton is the foundation of CDP to display extensive and excellent bioactivities, which is beneficial for CDPs' pharmaceutical research and development. The natural CDP products are well isolated from actinomycetes. These bacteria can synthesize DKP backbones with nonribosomal peptide synthetase (NRPS) or cyclodipeptide synthase (CDPS). Moreover, actinomycetes could produce a variety of CDPs through different enzymatic modification. The presence of these abundant and diversified catalysis indicates that actinomycetes are promising microbial resource for exploring CDPs. This review summarized the pathways for DKP backbones biosynthesis and their post-modification mechanism in actinomycetes. The aim of this review was to accelerate the genome mining of CDPs and their isolation, purification and structure identification, and to facilitate revealing the biosynthesis mechanism of novel CDPs as well as their synthetic biology design.
Actinobacteria/metabolism* ; Actinomyces/metabolism* ; Biological Products/metabolism* ; Bacteria/metabolism* ; Diketopiperazines/metabolism* ; Amino Acids

OBJECTIVE: To analyze the difference in the gene expression, amino acid and carnitine levels in the cervical secretions between the endometria of pre-receptive and receptive stages, with an aim to provide clues for identifying new molecular markers for endometrial receptivity. METHODS: Fifty nine infertile women treated at the Department of Reproductive Medicine of Linyi People's Hospital from January 6, 2020 to January 31, 2022 were selected as as the study subjects, which were matched with 3 pairs (6 cases) of infertile women preparing for embryo transfer based on factors such as age, body mass index, and length of infertility. Endometrial tissue samples were collected for gene transcription and expression analysis. Twenty five women who had become pregnant through assisted reproductive technology were selected as the control group, and 28 non-pregnant women receiving ovulation monitoring at the Outpatient Department were enrolled as the case group. Status of endometrial receptivity was determined by ultrasonography. In the former group, endometrial tissues were sampled for sequencing, and GO and KEGG database enrichment analysis of differentially expressed genes was carried out. In the latter group, cervical secretions were collected, and amino acid and carnitine levels were measured by mass spectrometry. Statistical analysis was carried out using rank sum test, t test and chi-square test with SPSS v25.0 software. RESULTS: No difference was found in the clinical data of the patients with regard to age, body mass index, infertility years, AMH, FSH, LH, E2, and type of infertility. Compared with the receptive endometrial tissues, there were 100 significantly up-regulated genes and 191 significantly down-regulated genes in the pre-receptive endometrial tissue, with the most significantly altered ones being HLA-DRB5 and MMP10. The biological processes, molecular functions and pathways enriched by more differentially expressed genes in GO and KEGG were mainly immune regulation, cell adhesion and tryptophan metabolism. Analysis of secretion metabolism also revealed a significant difference in the levels of amino acids and carnitine metabolites between the two groups (P < 0.05), in particular those of Alanine, Valine, 3-hydroxybutyrylcarnitine (C4OH) + malonylcarnitine (C3DC)/captoylcarnitine (C10). CONCLUSION A significant difference has been discovered in the levels of gene transcription and protein expression in the endometrial tissues from the pre-receptive and receptive stages. The levels of amino acids and carnitine, such as Alanine, Valine, 3-hydroxybutyryl carnitine (C4OH)+malonyl carnitine (C3DC)/caproyl carnitine (C10), may be associated with the receptive status of the endometrium, though this need to be verified with larger samples.
Pregnancy ; Humans ; Female ; Infertility, Female/genetics* ; Endometrium/metabolism* ; Amino Acids/metabolism* ; Gene Expression ; Carnitine ; Alanine/metabolism* ; Valine/metabolism*

The synthesis of fine chemicals using multi-enzyme cascade reactions is a recent hot research topic in the field of biocatalysis. The traditional chemical synthesis methods were replaced by constructing in vitro multi-enzyme cascades, then the green synthesis of a variety of bifunctional chemicals can be achieved. This article summarizes the construction strategies of different types of multi-enzyme cascade reactions and their characteristics. In addition, the general methods for recruiting enzymes used in cascade reactions, as well as the regeneration of coenzyme such as NAD(P)H or ATP and their application in multi-enzyme cascade reactions are summarized. Finally, we illustrate the application of multi-enzyme cascades in the synthesis of six bifunctional chemicals, including ω-amino fatty acids, alkyl lactams, α, ω-dicarboxylic acids, α, ω-diamines, α, ω-diols, and ω-amino alcohols.
Amino Acids ; Biocatalysis ; Amino Alcohols ; Coenzymes/metabolism* ; Diamines