Analysis of splice variants of the human protein disulfide isomerase (P4HB) gene

Research Progress of Disulfide Bond Based Tumor Microenvironment Targeted Drug Delivery System

Cancer poses a significant threat to human life and health. Chemotherapy is currently one of the effective cancer treatments, but many chemotherapy drugs have cell toxicity, low solubility, poor stability, a narrow therapeutic window, and unfavorable pharmacokinetic properties. To solve the above problems, target drug delivery to tumor cells, and reduce the side effects of drugs, an anti-tumor drug delivery system based on tumor microenvironment has become a focus of research in recent years. The construction of a reduction-sensitive nanomedicine delivery system based on disulfide bonds has attracted much attention. Disulfide bonds have good reductive responsiveness and can effectively target the high glutathione (GSH) levels in the tumor environment, enabling precise drug delivery. To further enhance targeting and accelerate drug release, disulfide bonds are often combined with pH-responsive nanocarriers and highly expressed ligands in tumor cells to construct drug delivery systems. Disulfide bonds can connect drug molecules and polymer molecules in the drug delivery system, as well as between different drug molecules and carrier molecules. This article summarized the drug delivery systems (DDS) that researchers have constructed in recent years based on disulfide bond drug delivery systems targeting the tumor microenvironment, disulfide bond cleavage-triggering conditions, various drug loading strategies, and carrier design. In this review, we also discuss the controlled release mechanisms and effects of these DDS and further discuss the clinical applicability of delivery systems based on disulfide bonds and the challenges faced in clinical translation.

Construction of ceRNA regulatory networks for active pulmonary tuberculosis

Delayed diagnosis in patients with pulmonary tuberculosis (PTB) often leads to serious public health problems. High throughput sequencing was used to determine the expression levels of lncRNAs, mRNAs, and miRNAs in the lesions and adjacent health lung tissues of patients with PTB. Their differential expression profiles between the two groups were compared, and 146 DElncRs, 447 DEmRs, and 29 DEmiRs were obtained between lesions and adjacent health tissues in patients with PTB. Enrichment analysis for mRNAs showed that they were mainly involved in Th1, Th2, and Th17 cell differentiation. The lncRNAs, mRNAs with target relationship with miRNAs were predicted respectively, and correlation analysis was performed. The ceRNA regulatory network was obtained by comparing with the differentially expressed transcripts (DElncRs, DEmRs, DEmiRs), then 2 lncRNAs mediated ceRNA networks were established. The expression of genes within the network was verified by quantitative real-time PCR (qRT-PCR). Flow cytometric analysis revealed that the proportion of Th1 cells and Th17 cells was lower in PTB than in controls, while the proportion of Th2 cells increased. Our results provide rich transcriptome data for a deeper investigation of PTB. The ceRNA regulatory network we obtained may be instructive for the diagnosis and treatment of PTB.

The Effect of N6-Methyladenosine Regulators and m6A Reader YTHDC1-Mediated N6-Methyladenosine Modification Is Involved in Oxidative Stress in Human Aortic Dissection

Aortic dissection (AD) develops pathological changes in the separation of the true and false aortic lumen, with high lethality. m6A methylation and oxidative stress have also been shown to be involved in the onset of AD. Through bioinformatics methods, three differentially expressed m6A regulators (YTHDC1, YTHDC2, and RBM15) were excavated from the GSE52093 dataset in the Gene Expression Omnibus (GEO) database, and functional enrichment analysis of the differentially expressed genes (DEGs) regulated by m6A regulators was performed. Then, the genes with oxidative stress-related functions among these genes were found. The protein interaction network of the oxidative stress-related genes and the competing endogenous RNA- (ceRNA-) miRNA-mRNA network were constructed. Among them, DHCR24, P4HB, and PDGFRA, which have m6A differences in AD samples, were selected as key genes. We also performed immune infiltration analysis, as well as cell-gene correlation analysis, on samples from the dataset. The results showed that YTHDC1 was positively correlated with macrophage M1 and negatively correlated with macrophage M2. Finally, we extracted AD and healthy aorta RNA and protein from human tissues that were taken from AD patients and patients who received heart transplants, performed quantitative real-time PCR (qRT-PCR) on YTHDC2 and RBM15, and performed qRT-PCR and western blot (WB) detection on YTHDC1 to verify their differences in AD. The mRNA and protein levels of YTHDC1 were consistent with the results of bioinformatics analysis and were downregulated in AD. Immunofluorescence (IF) was used to colocalize YTHDC1 and endothelial cell marker CD31. After knocking down YTHDC1 in human umbilical vein endothelial cells (HUVECs), reactive oxygen species (ROS) levels had a tendency to increase and the expression of peroxide dismutase SOD2 was decreased. This study provides assistance in discovering the role of m6A regulator YTHDC1 in AD. In particular, m6A modification participates in oxidative stress and jointly affects AD.

Splice variants of protein disulfide isomerase - identification, distribution and functional characterization in the rat

BACKGROUND

Protein Disulfide Isomerase (PDI) enzyme is an emerging therapeutic target in oncology and hematology. Although PDI reductase activity has been studied with isolated fragments of the protein, natural structural variations affecting reductase activity have not been addressed.

METHODS

In this study, we discovered four coding splice variants of the Pdi pre-mRNA in rats. In vitro Michaelis constants and apparent maximum steady-state rate constants after purification and distribution in different rat tissues were determined.

RESULTS

The consensus sequence was found to be the most expressed splice variant while the second most expressed variant represents 15 to 35% of total Pdi mRNA. The third variant shows a quasi-null expression profile and the fourth was not quantifiable. The consensus sequence splice variant and the second splice variant are widely expressed (transcription level) in the liver and even more present in males. Measurements of the reductase activity of recombinant PDI indicate that the consensus sequence and third splice variant are fully active variants. The second most expressed variant, differing by a lack of signal peptide, was found active but less than the consensus sequence.

GENERAL SIGNIFICANCE

Our work emphasizes the importance of taking splice variants into account when studying PDI-like proteins to understand the full biological functionalities of PDI.

Catabolism of Hydroxyproline in Vertebrates: Physiology, Evolution, Genetic Diseases and New siRNA Approach for Treatment

Hydroxyproline is one of the most prevalent amino acids in animal proteins. It is not a genetically encoded amino acid, but, rather, it is produced by the post-translational modification of proline in collagen, and a few other proteins, by prolyl hydroxylase enzymes. Although this post-translational modification occurs in a limited number of proteins, its biological significance cannot be overestimated. Considering that hydroxyproline cannot be re-incorporated into pro-collagen during translation, it should be catabolized following protein degradation. A cascade of reactions leads to production of two deleterious intermediates: glyoxylate and hydrogen peroxide, which need to be immediately converted. As a result, the enzymes involved in hydroxyproline catabolism are located in specific compartments: mitochondria and peroxisomes. The particular distribution of catabolic enzymes in these compartments, in different species, depends on their dietary habits. Disturbances in hydroxyproline catabolism, due to genetic aberrations, may lead to a severe disease (primary hyperoxaluria), which often impairs kidney function. The basis of this condition is accumulation of glyoxylate and its conversion to oxalate. Since calcium oxalate is insoluble, children with this rare inherited disorder suffer from progressive kidney damage. This condition has been nearly incurable until recently, as significant advances in substrate reduction therapy using small interference RNA led to a breakthrough in primary hyperoxaluria type 1 treatment.