Downregulation of AANAT by c-Fos in tubular epithelial cells with membranous nephropathy

The involvement of endogenous melatonin in LPS-induced M1-like macrophages and its underlying synthesis mechanism regulated by IRF3

Melatonin (MLT) has been shown to induce polarization of macrophages towards M2-like phenotype and inhibit polarization of macrophages towards M1-like phenotype through exogenous administration, which affects the development of many macrophage polarization-related diseases, such as infectious diseases, cardiovascular diseases, bone diseases, and tumors. However, whether endogenous melatonin has similar influences on macrophage polarization as exogenous melatonin is still under investigation. This study revealed that the process of lipopolysaccharide (LPS) inducing macrophages to polarize towards M1-like phenotype was accompanied by an increase in endogenous MLT secretion. To explore the role of increased endogenous MLT in the polarization process of macrophages, whether similar to the function of exogenous MLT in inhibiting polarization of macrophages towards M1-like phenotype, we established LPS-induced MLT deficiency models in vitro to investigate the effects of endogenous MLT on the secretion of cytokines, co-stimulatory molecules, ROS, and phagocytic function in LPS-induced M1-like macrophages. Additionally, we aimed to elucidate the mechanism by which LPS affects the secretion of endogenous MLT by macrophages. Our results confirm that LPS induces transcription of Aanat through the TLR4/TRIF pathway, consequently facilitating the secretion of MLT by macrophages. In this way, IRF3 is the main transcription factor that regulates Aanat transcription. Endogenous MLT plays a role in inhibiting the polarization of macrophages towards M1 phenotype and delaying cell apoptosis during LPS-induced polarization towards M1 phenotype. This phenomenon may be a form of self-protection that occurs when macrophages engulf pathogens while avoiding oxidative stress and apoptosis caused by LPS. This conclusion clarifies the role of endogenous MLT in the clearance of pathogens by macrophages, providing a theoretical basis for understanding its role in innate immunity.

Molecular characterization of PANoptosis-related genes in chronic kidney disease

Chronic kidney disease (CKD) is characterized by fibrosis and inflammation in renal tissues. Several types of cell death have been implicated in CKD onset and progression. Unlike traditional forms of cell death, PANoptosis is characterized by the crosstalk among programmed cell death pathways. However, the interaction between PANoptosis and CKD remains unclear. Here, we used bioinformatics methods to identify differentially expressed genes and differentially expressed PANoptosis-related genes (DE-PRGs) using data from the GSE37171 dataset. Following this, we further performed gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and gene set enrichment analysis using the data. We adopted a combined approach to select hub genes, using the STRING database and CytoHubba plug-in, and we used the GSE66494 as a validation dataset. In addition, we constructed ceRNA, transcription factor (TF)-gene, and drug-gene networks using Cytoscape. Lastly, we conducted immunohistochemical analysis and western blotting to validate the hub genes. We identified 57 PANoptosis-associated genes as DE-PRGs. We screened nine hub genes from the 57 DE-PRGs. We identified two hub genes (FOS and PTGS2) using the GSE66494 database, Nephroseq, immunohistochemistry, and western blotting. A common miRNA (Hsa-miR-101-3p) and three TFs (CREB1, E2F1, and RELA) may play a crucial role in the onset and progression of PANoptosis-related CKD. In our analysis of the drug-gene network, we identified eight drugs targeting FOS and 52 drugs targeting PTGS2.

Development and application of an amplified luminescent proximity homogeneous assay-linked immunosorbent assay for the accurate quantification of kidney injury molecule-1

Background: Kidney injury molecule-1 (Kim-1), a specific marker of kidney injury, is usually not expressed in normal kidneys or at very low levels but is highly expressed in injured renal tubular epithelial cells until the damaged cells recover completely. Therefore, we aimed to develop an efficient and highly sensitive assay to accurately quantify Kim-1 levels in human serum and urine. Methods: In this study, a novel immunoassay was developed and named amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA). Anti-Kim-1 antibodies can be directly coupled to carboxyl-modified donor and acceptor beads for the rapid detection of Kim-1 by double-antibody sandwich method. Serum and urine samples for Kim-1 measurements were obtained from 129 patients with nephropathy and 17 healthy individuals. Results: The linear range of Kim-1 detected by AlphaLISA was 3.83-5000 pg/mL, the coefficients of variation of intra-assay and inter-assay batches were 3.36%-4.71% and 5.61%-11.84%, respectively, and the recovery rate was 92.31%-99.58%. No cross reactions with neutrophil gelatinase-associated lipocalin, liver-type fatty acid binding protein, and matrix metalloproteinase-3 were observed. A good correlation (R 2 = 0.9086) was found between the findings of Kim-1-TRFIA and Kim-AlphaLISA for the same set of samples. In clinical trials, both serum and urine Kim-1 levels were significantly higher in patients with nephropathy than in healthy individuals, especially in patients with acute kidney injury. Furthermore, serum Kim-1 was superior to urinary Kim-1 in distinguishing between patients with nephropathy and healthy individuals. Conclusion: The developed Kim-1-AlphaLISA is highly efficient, precise, and sensitive, and it is suitable for the rapid detection of patients with acute kidney injury.

Proteomic analysis of glomeruli, tubules and renal interstitium in idiopathic membranous nephropathy (IMN): A statistically observational study

Idiopathic membranous nephropathy (IMN) is a common type of primary glomerulonephritis, which pathogenesis are highly involved protein and immune regulation. Therefore, we investigated protein expression in different microregions of the IMN kidney tissue. We used laser capture microdissection and mass spectrometry to identify the proteins in the kidney tissue. Using MSstats software to identify the differently expressed protein (DEP). Gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis were used to predict and enrich the potential functions of the DEPs, and DEPs were compared to the Public data in the gene expression omnibus (GEO) database for screening biomarkers of IMN. Immune infiltration analysis was used to analyze the immune proportion in IMN. Three significantly up-regulated proteins were identified in the glomeruli of patients with IMN; 9 significantly up-regulated and 6 significantly down-regulated proteins were identified in the interstitium of patients with IMN. Gene ontology analysis showed that the DEPs in the glomerulus and interstitium were mostly enriched in "biological regulation, the immune system, and metabolic processes." Kyoto Encyclopedia of Genes and Genomes analysis showed that the DEPs in the glomerulus and interstitium were mostly enriched in the "immune system" and the "complement and coagulation cascades. " According to the public information of the GEO database, DEPs in our study, Coatomer subunit delta Archain 1, Laminin subunit alpha-5, and Galectin-1 were highly expressed in the IMN samples from the GEO database; in the immune infiltration analysis, the proportion of resting memory CD4 T cells and activated NK cells in IMN were significantly higher than in the normal group. This study confirmed that there were significant differences in protein expression in different micro-regions of patients with IMN, The protein Coatomer subunit delta Archain 1, Laminin subunit alpha 5, Galectin-1 are potential biomarkers of IMN, the memory T cells CD4 and NK cells, maybe involved in the immunologic mechanism in the development of IMN.

Identification of ferroptosis-related genes and pathways in diabetic kidney disease using bioinformatics analysis

Diabetic kidney disease (DKD) is a major public health issue because of its refractory nature. Ferroptosis is a newly coined programmed cell death characterized by the accumulation of lipid reactive oxygen species (ROS). However, the prognostic and diagnostic value of ferroptosis-related genes (FRGs) and their biological mechanisms in DKD remain elusive. The gene expression profiles GSE96804, GSE30566, GSE99339 and GSE30528 were obtained and analyzed. We constructed a reliable prognostic model for DKD consisting of eight FRGs (SKIL, RASA1, YTHDC2, SON, MRPL11, HSD17B14, DUSP1 and FOS). The receiver operating characteristic (ROC) curves showed that the ferroptosis-related model had predictive power with an area under the curve (AUC) of 0.818. Gene functional enrichment analysis showed significant differences between the DKD and normal groups, and ferroptosis played an important role in DKD. Consensus clustering analysis showed four different ferroptosis types, and the risk score of type four was significantly higher than that of other groups. Immune infiltration analysis indicated that the expression of macrophages M2 increased significantly, while that of neutrophils and mast cells activated decreased significantly in the high-risk group. Our study identified and validated the molecular mechanisms of ferroptosis in DKD. FRGs could serve as credible diagnostic biomarkers and therapeutic targets for DKD.