The glycine N-acyltransferases, GLYAT and GLYATL1, contribute to the detoxification of isovaleryl-CoA - an in-silico and in vitro validation

Downregulation of GLYAT correlates with tumour progression and poor prognosis in hepatocellular carcinoma

Glycine N-acyltransferase (GLYAT), known to influence glycine metabolism, has been implicated in the progression of various malignant tumours. However, its clinical relevance in hepatocellular carcinoma (HCC) remains unexplored. Here, GLYAT expression levels in HCC tissues were significantly reduced compared to normal liver tissues. Similarly, GLYAT expression levels in Huh 7, HepG2, PLC and SK-HEP1 were lower than those in LO2. Receiver operating characteristic curve analysis demonstrated that GLYAT exhibited good diagnostic performance for HCC. Kaplan-Meier analyses suggested that decreased GLYAT expression was correlated with poorer progress in HCC. Low GLYAT expression was significantly associated with gender and histologic grade. Multivariate Cox regression analysis identified low GLYAT expression and T stage as independent prognostic factors. Nomograms based on GLYAT mRNA expression and T stage showed good concordance with actual survival rates at 1, 2, 3 and 5 years. Moreover, GLYAT downregulation in the Huh 7 cell line enhanced cell proliferation, invasion and migration abilities, while GLYAT overexpression in the HepG2 cell line inhibited these abilities. HCC patients with low GLYAT expression exhibited a predisposition to immune escape and poor response to immunotherapy. This research revealed that GLYAT holds promise as both a prognostic biomarker and a potential therapeutic target in HCC.

GLYAT suppresses liver cancer and clear cell renal cell carcinoma progression by downregulating ROCK1 expression

Background

The liver and kidney are important metabolic organs in the body and common sites of tumor occurrence. Glycine-N-acyltransferase (GLYAT) is primarily expressed in the liver and kidney and downregulated in several tumors. But its specific functions and molecular mechanisms in liver cancer and clear cell renal cell carcinoma (ccRCC) have not yet been fully elucidated. The aim of this study was to explore the role and clinical significance of GLYAT in liver cancer and ccRCC.

Methods

This study used proteomics technology to identify differentially expressed proteins in liver cancer. Western blot and immunohistochemistry (IHC) were used to analyze the protein expression pattern of GLYAT. assays were performed in liver cancer and ccRCC cells. Xenograft models in nude mice were used to confirm the roles of GLYAT in liver cancer. Moreover, the downstream regulatory proteins of GLYAT were identified by proteomics.

Results

GLYAT was lowly expressed in liver cancer and ccRCC. Immunofluorescence staining indicated that GLYAT was mainly expressed in the cytoplasm, particularly the mitochondria. Kaplan-Meier curves showed that the low protein expression of GLYAT was correlated with a poor prognosis in liver cancer and ccRCC patients. Moreover, GLYAT expression was associated with several clinical parameters in liver cancer. Cell experiments showed that the overexpression of GLYAT inhibited cell proliferation and migration abilities; however, interfering GLYAT protein expression rescued these abilities in GLYAT overexpression (GLYAT-OE) cells. In vivo assays confirmed the tumor-suppressor function of GLYAT in liver cancer. Moreover, our research showed that GLYAT downregulated Rho-associated coiled-coil-containing protein kinase 1 (ROCK1).

Conclusions

Our study showed that GLYAT is lowly expressed in liver cancer and ccRCC, emphasizing its prognostic significance. It also showed that GLYAT inhibits the progression of liver cancer and ccRCC by downregulating ROCK1.

Pharmacokinetics of aspirin: evaluating shortcomings in the literature

INTRODUCTION

Aspirin is known for its therapeutic benefits in preventing strokes and relieving pain. However, it is toxic to some individuals, and the biological mechanisms causing toxicity are unknown. Limited literature is available on the role of glycine conjugation as the principal pathway in aspirin detoxification. Previous studies have quantified this two-step enzyme reaction as a singular enzymatic process. Consequently, the individual contributions of these enzymes to the kinetics remain unclear.

AREAS COVERED

This review summarized the available information on the pharmacokinetics and detoxification of aspirin by the glycine conjugation pathway. Literature searches were conducted using Google Scholar and the academic journal databases accessible through the North-West University Library. Furthermore, the factors affecting interindividual variation in aspirin metabolism and what is known regarding aspirin toxicity were discussed.

EXPERT OPINION

The greatest drawback in understanding the pharmacokinetics of aspirin is the limited information available on the substrate preference of the xenobiotic ligase (ACSM) responsible for activating salicylate to salicyl-CoA. Furthermore, previous pharmacokinetic studies did not consider the contribution of other substrates from the diet or genetic variants, to the detoxification rate of glycine conjugation. Impaired glycine conjugation might contribute to adverse health effects seen in Reye's syndrome and cancer.

Genes Selectively Expressed in Rat Organs

Background

Understanding organic functions at a molecular level is important for scientists to unveil the disease mechanism and to develop diagnostic or therapeutic methods.

Aims

The present study tried to find genes selectively expressed in 11 rat organs, including the adrenal gland, brain, colon, duodenum, heart, ileum, kidney, liver, lung, spleen, and stomach.

Materials and Methods

Three normal male Sprague-Dawley (SD) rats were anesthetized, their organs mentioned above were harvested, and RNA in the fresh organs was extracted. Purified RNA was reversely transcribed and sequenced using the Solexa high-throughput sequencing technique. The abundance of a gene was measured by the expected value of fragments per kilobase of transcript sequence per million base pairs sequenced (FPKM). Genes in organs with the highest expression level were sought out and compared with their median value in organs. If a gene in the highest expressed organ was significantly different (p < 0.05) from that in the medianly expressed organ, accompanied by q value < 0.05, and accounted for more than 70% of the total abundance, the gene was assumed as the selective gene in the organ.

Results & Discussion

The Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) pathways were enriched by the highest expressed genes. Based on the criterion, 1,406 selective genes were screened out, 1,283 of which were described in the gene bank and 123 of which were waiting to be described. KEGG and GO pathways in the organs were partly confirmed by the known understandings and a good portion of the pathways needed further investigation.

Conclusion

The novel selective genes and organic functional pathways are useful for scientists to unveil the mechanisms of the organs at the molecular level, and the selective genes' products are candidate disease markers for organs.

Enzymatic Strategies for the Biosynthesis of N-Acyl Amino Acid Amides

Amide bond-containing biomolecules are functionally significant and useful compounds with diverse applications. For example, N-acyl amino acids (NAAAs) are an important class of lipoamino acid amides with extensive use in food, cosmetic and pharmaceutical industries. Their conventional chemical synthesis involves the use of toxic chlorinating agents for carboxylic acid activation. Enzyme-catalyzed biotransformation for the green synthesis of these amides is therefore highly desirable. Here, we review a range of enzymes suitable for the synthesis of NAAA amides and their strategies adopted in carboxylic acid activation. Generally, ATP-dependent enzymes for NAAA biosynthesis are acyl-adenylating enzymes that couple the hydrolysis of phosphoanhydride bond in ATP with the formation of an acyl-adenylate intermediate. In contrast, ATP-independent enzymes involve hydrolases such as lipases or aminoacylases, which rely on the transient activation of the carboxylic acid. This occurs either through an acyl-enzyme intermediate or by favorable interactions with surrounding residues to anchor the acyl donor in a suitable orientation for the incoming amine nucleophile. Recently, the development of an alternative pathway involving ester-amide interconversion has unraveled another possible strategy for amide formation through esterification-aminolysis cascade reactions, potentially expanding the substrate scope for enzymes to catalyze the synthesis of a diverse range of NAAA amides.