5-aminovalanoic acid (5AVA) can be used as the precursor of new plastics nylon 5 and nylon 56, and is a promising platform compound for the synthesis of polyimides. At present, the biosynthesis of 5-aminovalanoic acid generally is of low yield, complex synthesis process and high cost, which hampers large-scale industrial production. In order to achieve efficient biosynthesis of 5AVA, we developed a new pathway mediated by 2-keto-6-aminohexanoate. By combinatory expression of L-lysine α-oxidase from Scomber japonicus, α-ketoacid decarcarboxylase from Lactococcus lactis and aldehyde dehydrogenase from Escherichia coli, the synthesis of 5AVA from L-lysine in Escherichia coli was achieved. Under the initial conditions of glucose concentration of 55 g/L and lysine hydrochloride of 40 g/L, the final consumption of 158 g/L glucose and 144 g/L lysine hydrochloride, feeding batch fermentation to produce 57.52 g/L of 5AVA, and the molar yield is 0.62 mol/mol. The new 5AVA biosynthetic pathway does not require ethanol and H₂O₂, and achieved a higher production efficiency as compared to the previously reported Bio-Chem hybrid pathway mediated by 2-keto-6-aminohexanoate.
Nylons ; Lysine/metabolism* ; Hydrogen Peroxide/metabolism* ; Metabolic Engineering ; Plastics/metabolism* ; Fermentation ; Escherichia coli/metabolism* ; Aminocaproates/metabolism*

Histone lysine methyltransferases (HKMTs) deposit methyl groups onto lysine residues on histones and play important roles in regulating chromatin structure and gene expression. The structures and functions of HKMTs have been extensively investigated in recent decades, significantly advancing our understanding of the dynamic regulation of histone methylation. Here, we review the recent progress in structural studies of representative HKMTs in complex with nucleosomes (H3K4, H3K27, H3K36, H3K79, and H4K20 methyltransferases), with emphasis on the molecular mechanisms of nucleosome recognition and trans-histone crosstalk by these HKMTs. These structural studies inform HKMTs' roles in tumorigenesis and provide the foundations for developing new therapeutic approaches targeting HKMTs in cancers.
Nucleosomes ; Histones/metabolism* ; Histone-Lysine N-Methyltransferase/metabolism* ; Lysine/metabolism* ; Methyltransferases/metabolism* ; Methylation

Objective: To investigate the effect of ubiquitin mutation at position 331 of tumor necrosis factor receptor related factor 6 (TRAF6) on the biological characteristics of colorectal cancer cells and its mechanism. Methods: lentivirus wild type (pCDH-3×FLAG-TRAF6) and mutation (pCDH-3×FLAG-TRAF6-331mut) of TRAF6 gene expression plasmid with green fluorescent protein tag were used to infect colorectal cancer cells SW480 and HCT116, respectively. The infection was observed by fluorescence microscope, and the expressions of TRAF6 and TRAF6-331mut in cells was detected by western blot. Cell counting kit-8 (CCK-8) and plate cloning test were used to detect the proliferation ability of colorectal cancer cells in TRAF6 group and TRAF6-331mut group, cell scratch test to detect cell migration, Transwell chamber test to detect cell migration and invasion, immunoprecipitation to detect the ubiquitination of TRAF6 and TRAF6-331mut with ubiquitinof lysine binding sites K48 and K63. Western blot was used to detect the effects of TRAF6 and TRAF6-331mut over expression on the nuclear factor kappa-B (NF-κB) and mitogen activated protein kinase mitogen-activated protein kinase (MAPK)/activating protein-1(AP-1) signal pathway. Results: The successful infection of colorectal cancer cells was observed under fluorescence microscope. Western blot detection showed that TRAF6 and TRAF6-331mut were successfully expressed in colorectal cancer cells. The results of CCK-8 assay showed that on the fourth day, the absorbance values of HCT116 and SW480 cells in TRAF6-331mut group were 1.89±0.39 and 1.88±0.24 respectively, which were lower than those in TRAF6 group (2.09±0.12 and 2.17±0.45, P=0.036 and P=0.011, respectively). The results of plate colony formation assay showed that the number of clones of HCT116 and SW480 cells in TRAF6-331mut group was 120±14 and 85±14 respectively, which was lower than those in TRAF6 group (190±21 and 125±13, P=0.001 and P=0.002, respectively). The results of cell scratch test showed that after 48 hours, the percentage of wound healing distance of HCT116 and SW480 cells in TRAF6-331mut group was (31±12)% and (33±14)%, respectively, which was lower than those in TRAF6 group [(43±13)% and (43±7)%, P=0.005 and 0.009, respectively]. The results of Transwell migration assay showed that the migration numbers of HCT116 and SW480 cells in TRAF6-331mut group were significantly lower than those in TRAF6 group (P<0.001 and P<0.002, respectively). The results of Transwell invasion assay showed that the number of membrane penetration of HCT116 and SW480 cells in TRAF6-331mut group was significantly lower than those in TRAF6 group (P=0.008 and P=0.009, respectively). The results of immunoprecipitation detection showed that the ubiquitin protein of K48 chain pulled by TRAF6-331mut was lower than that of wild type TRAF6 in 293T cells co-transfected with K48 (0.57±0.19), and the ubiquitin protein of K63 chain pulled down by TRAF6-331mut in 293T cells co-transfected with K63 was lower than that of wild type TRAF6 (0.89±0.08, P<0.001). Western blot assay showed that the protein expression levels of NF-κB, p-NF-κB and p-AP-1 in TRAF6-331mut-HCT116 cells were 0.63±0.08, 0.42±0.08 and 0.60±0.07 respectively, which were lower than those in TRAF6-HCT116 cells (P=0.002, P<0.001 and P<0.001, respectively). The expression level of AP-1 protein in TRAF6-HCT116 cells was 0.89±0.06, compared with that in TRAF6-HCT116 cells. The difference was not statistically significant (P>0.05). The protein expression levels of NF-κB, p-NF-κB and p-AP-1 in TRAF6-331mut-SW480 cells were 0.50±0.06, 0.51±0.04, 0.48±0.02, respectively, which were lower than those in TRAF6-SW480 cells (all P<0.001). There was no significant difference in AP-1 protein expression between TRAF6-331mut-SW480 cells and TRAF6-SW480 cells. Conclusion: The ubiquitin site mutation of TRAF6 gene at 331 may prevent the binding of TRAF6 and ubiquitin lysine sites K48 and K63, and then affect the expressions of proteins related to downstream NF-κB and MAPK/AP-1 signal pathways, and inhibit the proliferation, migration and invasion of colorectal cancer cells.
Humans ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Colorectal Neoplasms/pathology* ; Lysine/metabolism* ; NF-kappa B/metabolism* ; TNF Receptor-Associated Factor 6/metabolism* ; Transcription Factor AP-1/metabolism* ; Ubiquitin/metabolism*

The occurence and development of tumors is a complicated process, which not only depends on the mutation or deletion of genes, but also is affected by epigenetic regulation. Accumulating evidences have shown that epigenetic modifications play fundamental roles in transcriptional regulation, heterochromatin formation, X chromosome inactivation, DNA damage response and tumor development. SET domain containing lysine methyltransferase 7 (SETD7) was initially identified as an important lysine methyltransferase, which methylated histone and non-histone proteins. These modifications play fundamental roles. Once this modification disorders, it can directly lead to cell abnormalities and cause many diseases. Studies have shown that SETD7 is related to the occurence and development of various tumors, but the methylation sites of SETD7 and its regulatory mechanism have not been fully elucidated. This article summarizes the research progress of the role of SETD7 on histone and non-histone methylation modification in tumors and the molecular mechanism, in order to provide new therapeutic targets for tumor pathogenesis and diagnosis.
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Humans ; Epigenesis, Genetic ; Histone-Lysine N-Methyltransferase/metabolism* ; Lysine/metabolism* ; Lung Neoplasms/genetics* ; Histones/metabolism*

Carcinoma-associated fibroblasts (CAFs) are the main cellular components of the tumor microenvironment and promote cancer progression by modifying the extracellular matrix (ECM). The tumor-associated ECM is characterized by collagen crosslinking catalyzed by lysyl oxidase (LOX). Small extracellular vesicles (sEVs) mediate cell-cell communication. However, the interactions between sEVs and the ECM remain unclear. Here, we demonstrated that sEVs released from oral squamous cell carcinoma (OSCC)-derived CAFs induce collagen crosslinking, thereby promoting epithelial-mesenchymal transition (EMT). CAF sEVs preferably bound to the ECM rather than being taken up by fibroblasts and induced collagen crosslinking, and a LOX inhibitor or blocking antibody suppressed this effect. Active LOX (αLOX), but not the LOX precursor, was enriched in CAF sEVs and interacted with periostin, fibronectin, and bone morphogenetic protein-1 on the surface of sEVs. CAF sEV-associated integrin α2β1 mediated the binding of CAF sEVs to collagen I, and blocking integrin α2β1 inhibited collagen crosslinking by interfering with CAF sEV binding to collagen I. CAF sEV-induced collagen crosslinking promoted the EMT of OSCC through FAK/paxillin/YAP pathway. Taken together, these findings reveal a novel role of CAF sEVs in tumor ECM remodeling, suggesting a critical mechanism for CAF-induced EMT of cancer cells.
Humans ; Paxillin/metabolism* ; Protein-Lysine 6-Oxidase/metabolism* ; Carcinoma, Squamous Cell/pathology* ; Epithelial-Mesenchymal Transition ; Integrin alpha2beta1/metabolism* ; Mouth Neoplasms/pathology* ; Collagen/metabolism* ; Fibroblasts ; Extracellular Vesicles/metabolism* ; Cell Line, Tumor ; Tumor Microenvironment

OBJECTIVE: To investigate the effect of hyperoxia on intestinal metabolomics in mice. METHODS: Sixteen 8-week-old male C57BL/6 mice were randomly divided into hyperoxia group and control group, with 8 mice in each group. The hyperoxia group was exposed to 80% oxygen for 14 days. Mice were anesthetized and euthanized, and cecal contents were collected for untargeted metabolomics analysis by liquid chromatography-mass spectrometry (LC-MS) combined detection. Orthogonal partial least square discriminant analysis (OPLS-DA), volcano plot analysis, heat map analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the effects of hyperoxia on metabolism. RESULTS: (1) OPLS-DA analysis showed that R²Y was 0.967 and Q² was 0.796, indicating that the model was reliable. (2) Volcano plot and heat map analysis showed significant statistical differences in the expression levels of metabolites between the two groups, with 541 up-regulated metabolites, 64 down-regulated metabolites, and 907 no differences, while the elevated 5-hydroxy-L-lysine was the most significant differential metabolite induced by high oxygen. (3) KEGG pathway enrichment analysis showed that porphyrin and chlorophyll metabolism (P = 0.005), lysine degradation (P = 0.047), and aromatic compound degradation (P = 0.024) were the targets affected by hyperoxia. (4) Differential analysis of metabolic products through KEGG enrichment pathway showed that hyperoxia had a significant impact on the metabolism of porphyrin and chlorophyll, lysine, and aromatic compounds such as benzene and o-cresol. CONCLUSIONS Hyperoxia significantly induces intestinal metabolic disorders. Hyperoxia enhances the metabolism of porphyrins and chlorophyll, inhibits the degradation of lysine, and delays the degradation of aromatic compounds such as benzene and o-cresol.
Mice ; Male ; Animals ; Lysine ; Hyperoxia ; Benzene ; Mice, Inbred C57BL ; Metabolic Diseases ; Oxygen ; Chlorophyll ; Porphyrins ; Biomarkers/metabolism*

Traumatic brain injury (TBI) contributes to the key causative elements of neurological deficits. However, no effective therapeutics have been developed yet. In our previous work, extracellular vesicles (EVs) secreted by stem cells from human exfoliated deciduous teeth (SHED) offered new insights as potential strategies for functional recovery of TBI. The current study aims to elucidate the mechanism of action, providing novel therapeutic targets for future clinical interventions. With the miRNA array performed and Real-time PCR validated, we revealed the crucial function of miR-330-5p transferred by SHED-derived EVs (SHED-EVs) in regulating microglia, the critical immune modulator in central nervous system. MiR-330-5p targeted Ehmt2 and mediated the transcription of CXCL14 to promote M2 microglia polarization and inhibit M1 polarization. Identified in our in vivo data, SHED-EVs and their effector miR-330-5p alleviated the secretion of inflammatory cytokines and resumed the motor functional recovery of TBI rats. In summary, by transferring miR-330-5p, SHED-EVs favored anti-inflammatory microglia polarization through Ehmt2 mediated CXCL14 transcription in treating traumatic brain injury.
Animals ; Brain Injuries, Traumatic/therapy* ; Chemokines, CXC/metabolism* ; Extracellular Vesicles/metabolism* ; Histocompatibility Antigens/metabolism* ; Histone-Lysine N-Methyltransferase/metabolism* ; Humans ; MicroRNAs/metabolism* ; Microglia/metabolism* ; Rats ; Stem Cells/metabolism*

Lysine specific demethylase 1 (LSD1), a transcriptional corepressor or coactivator that serves as a demethylase of histone 3 lysine 4 and 9, has become a potential therapeutic target for cancer therapy. LSD1 mediates many cellular signaling pathways and regulates cancer cell proliferation, invasion, migration, and differentiation. Recent research has focused on the exploration of its pharmacological inhibitors. Natural products are a major source of compounds with abundant scaffold diversity and structural complexity, which have made a major contribution to drug discovery, particularly anticancer agents. In this review, we briefly highlight recent advances in natural LSD1 inhibitors over the past decade. We present a comprehensive review on their discovery and identification process, natural plant sources, chemical structures, anticancer effects, and structure-activity relationships, and finally provide our perspective on the development of novel natural LSD1 inhibitors for cancer therapy.
Antineoplastic Agents/therapeutic use* ; Enzyme Inhibitors/therapeutic use* ; Histone Demethylases/metabolism* ; Humans ; Lysine/therapeutic use* ; Neoplasms/drug therapy*

OBJECTIVES: Our previous study has verified that high level of SET and MYND domain-containing protein 2 (SMYD2) plays an important role in acquiring aggressive ability for liver cancer cells in hepatocellular carcinoma. MiR-200b as a tumor suppressor gene involves in a variety of cancers. This study aims to investigate the correlation between miR-200b and SMYD2 in hepatocellular carcinoma and the underlying mechanism. METHODS: Firstly, the levels of SMYD2 and miR-200b in hepatocellular carcinoma tissues and matched adjacent non-tumor liver tissues were tested with real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Secondly, we evaluated the interaction between miR-200b and SMYD2 using dual-luciferase reporter assay. Thirdly, we elucidated the effect of miR-200b on SMYD2 and its downstream targets p53/CyclinE1. Finally, we silenced SMYD2 in hepatocellular carcinoma cell lines to investigate its effect on tumor proliferation and cell cycle progression, and further confirmed the correlation among SMYD2 and p53/CyclinE1. RESULTS: Compared with the matched adjacent non-tumor liver tissues, miR-200b was obviously decreased, and SMYD2 was significantly increased in hepatocellular carcinoma (both P<0.05). Spearman's rank correlation revealed that miR-200b expression was negatively correlated with SMYD2 (P<0.01). Computer algorithm and dual-luciferase reporter assay revealed that miR-200b directly targeted and suppressed SMYD2 in HEK 293T cells. The down-regulated miR-200b expression promoted hepatoma cell proliferation (P<0.05) and increased SMYD2 expression(P<0.01), while the up-regulated expression of miR-200b had an opposite effect. The knockdown of SMYD2 suppressed the proliferation of MHCC-97L cells (P<0.01), down-regulated CyclinE1, and up-regulated p53 expression (both P<0.05). CONCLUSIONS MiR-200b is involved in hepatocellular carcinoma progression via targeting SMYD2 and regulating SMYD2/p53/CyclinE1 signaling pathway and may be used as a potential target for hepatocellular carcinoma treatment.
Humans ; Carcinoma, Hepatocellular/pathology* ; Tumor Suppressor Protein p53/metabolism* ; MicroRNAs/metabolism* ; Cell Line, Tumor ; Signal Transduction ; Liver Neoplasms/pathology* ; Cell Proliferation/genetics* ; Histone-Lysine N-Methyltransferase/metabolism*

Objective To obtain the proteome and acetylome profiles of livers in mice during normal aging.Methods We applied tandem mass tag labeling and liquid chromatography tandem mass spectrometry and achieved proteome and acetylome data in C57BL/6J male mice aged 2 and 18 months under physiological conditions.Results A total of 4712 proteins were quantified by proteome profiling,and 4818 acetylated sites in 1367 proteins by acetylome profiling.The proteome and acetylome revealed moderate differences in the livers of young and old mice.There were 195 differentially expressed proteins in the proteome and 113 differentially expressed acetylated sites corresponding to 76 proteins in the acetylome.Functional enrichment analysis for the proteome showed that aging-associated upregulated proteins were mainly involved in fatty acid metabolism,epoxygenase P450 pathway,drug catabolic process,organic hydroxy compound metabolic process,and arachidonic acid metabolic process,while the downregulated proteins were related to regulation of gene silencing,nucleosome assembly,protein heterotetramerization,response to interferon,protein-DNA complex assembly and other processes.For the acetylome,the proteins with aging-associated upregulated acetylated sites mainly participated in cofactor metabolism,small molecule catabolic process,ribose phosphate metabolic process,ribonucleotide metabolic process,and purine-containing compound metabolic process,while the proteins with downregulated acetylated sites were associated with sulfur compound metabolic process,response to unfolded protein,and amino acid metabolic process.Conclusion We profiled the proteome and acetylome of livers in mice during normal aging and generated datasets for further research on aging.
Acetylation ; Aging ; Animals ; Liver ; Lysine/metabolism* ; Male ; Mice ; Mice, Inbred C57BL ; Proteome/metabolism*