Objective:To investigate the effects and underlying mechanisms of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/NF-κB signaling pathway in human kidney-2(HK-2) cells of hyperuricemic nephropathy.Methods:HK-2 cells were cultured in vitro and randomly divided into control group and experimental group. The experimental group was induced by high uric acid (720 μmol/L) immersion for 48 h to establish a cell model of hyperuricemic nephropathy in vitro and subsequently divided into hyperuricemic group, overexpressed protease activated receptor 2 (PAR2) and knockdown PAR2 group. The expressions of PAR2, PI3K, AKT, NF-κB mRNA were measured by real-time PCR. The expressions of PAR2, PI3K, AKT and NF-κB protein were measured by Western blotting. The expressions of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), pro-interleukin-1β (pro-IL-1β), interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) were detected by enzyme linked immunosorbent assay (ELISA). Results:(1) Compared with the control group, the expressions of PAR2, PI3K, AKT and NF-κB mRNA and protein in hyperuricemic group were significantly increased (all P<0.05), the expressions of TNF-α, MCP-1, IL-6, pro-IL-1β, IL-1β and TGF-β1 in the supernatant in hyperuricemic group were significantly increased (all P<0.01). (2) Compared with the hyperuricemic group, the expressions of PAR2, PI3K, AKT and NF-κB mRNA and protein in overexpressed PAR2 group were significantly increased (all P<0.05), the expressions of TNF-α, MCP-1, IL-6, IL-1β and TGF-β1 in the supernatant were significantly increased (all P<0.05). (3) Compared with the hyperuricemic group, the expression of PAR2, PI3K, AKT and NF-κB mRNA and protein in knockdown PAR2 group were significantly decreased (all P<0.05), the expressions of IL-6, pro-IL-1β, IL-1β and TGF-β1 in the supernatant were significantly decreased (all P<0.05). Conclusions:In the process of uric acid-induced HK-2 cell damage, uric acid significantly up-regulates the expression of PI3K/AKT/NF-κB signaling pathway by activating PAR2, leading to a marked increase in inflammatory damage. Knocking down PAR2 inhibits the expression of PI3K/AKT/NF-κB signaling pathway, which can effectively reduce the inflammatory damage of HK-2 cells.

Objective:To establish a mouse model of intra-jugular arteriovenous fistula (AVF) to screen differentially expressed genes in the process of intimal stenosis of AVF for investigating the abnormal expression signaling pathways and the mechanisms.Methods:Forty-six male C57BL/6 mice were randomly divided into AVF group ( n=23) and sham-operated group ( n=23). The AVF group underwent internal jugular arteriovenous fistuloplasty, and the sham-operated group separated the right external jugular vein and common carotid artery and then sutured the incision. The whole-genome sequences of mice with AVF stenosis were determined by transcriptomic reversible chain terminator and synthetic sequencing. The microarray data set was established, and the Benjamini & Hochberg method of gene microarray data analysis was applied to screen the differentially expressed genes. The differentially expressed genes were screened by R-language enrichment analysis. Then, gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) were performed. The subcellular localization of the differentially expressed genes was performed by BUSCA software. The protein network interaction of differentially expressed genes was analyzed by using STRING database and Cytoscape software. Results:In the AVF group, 21 mice were successfully modeled and 2 mice failed. Therefore, there were 21 mice in the AVF group and only 21 mice in the sham-operated group. This mouse internal jugular AVF model was innovated using the continuous-interrupted suture method, which improved the success rate of modeling this model. The differential gene sequencing analysis showed that there were 2 514 differentially expressed genes in the AVF process, including 1 323 up-regulated genes and 1 191 down-regulated genes. GO functional enrichment analysis showed that the differential genes were mainly enriched in metabolic process, activation, redox, mitochondria and so on. KEGG pathway enrichment analysis showed that the differential genes were enriched in metabolism, energy substance synthesis, diabetes, oxidative stress and so on. Statistical analysis of subcellular localization showed that the differences were mainly in mitochondrial proteins (24.24%), cytoplasmic proteins (17.51%), nuclear proteins (13.13%), cell membrane proteins (11.45%), and extracellular proteins (10.77%).Conclusions:Mitochondrial oxidative stress injury may be involved in the pathological damage process of endothelial proliferation stenosis in the AVF.

Objective:Clamping bilateral renal arteries with refined surgical methods to establish the rat renal ischemia-reperfusion injury (RIRI) model, and study the protective mechanism of ischemic preconditioning renal (IPC) tubular cell-derived exosomes in RIRI.Methods:25 female Sprague Dawley (SD) rats were divided into sham group, model group, inactivated group, normoxic group, IPC group. In the sham operation group, after bilateral renal arteries were dissociated, the back incision was disinfected and closed. The model group established RIRI model; RIRI models were established in inactivated group, normoxia group and IPC group, and then 200 μg of inactivated exosomes, normal exosomes and IPC exosomes were injected into the caudal vein 24 hours after operation. Serum creatinine (Scr) and urea nitrogen (BUN) levels were detected. The pathological changes of renal tissue were observed under light microscope. Transmission electron microscopy (TEM) was used to observe the shape and size of renal tubular exosomes. Nanoparticle tracking analysis (NTA)was used to detect the concentration and size of renal tubular exosomes.Results:Compared with the sham group, the Scr and BUN levels in the model group were significantly elevated ( P<0.01). Renal pathological changes in the model group showed damaged of the tubular structure, necrosis and shedding of tubular epithelial cells, and a large number of inflammatory cells accumulated in the renal interstitial tissue with varying degrees of edema. Compared with the inactivated group, the Scr and BUN levels significantly decreased in the normoxic group and IPC group ( P<0.01). Renal pathological changes in the normoxic group and IPC group showed that the renal tubular cell necrosis alleviated, inflammatory was reduced, the improved edema. Compared with the normoxic group, the Scr and BUN levels in the IPC group were further reduced ( P<0.01). Renal pathological changes in the IPC group showed that the inflammatory cells were significantly reduced, the cell edema was significantly improved, and the cell apoptosis was significantly reduced. Conclusions:Clamping bilateral renal arteries with refined surgical methods is the main and optimal way to build a rat model of RIRI. IPC tubular cell-derived exosomes have protective and repair effects on RIRI.

Activation of the heart normally begins in the sinoatrial node (SAN). Electrical impulses spontaneously released by SAN pacemaker cells (SANPCs) trigger the contraction of the heart. However, the cellular nature of SANPCs remains controversial. Here, we report that SANPCs exhibit glutamatergic neuron-like properties. By comparing the single-cell transcriptome of SANPCs with that of cells from primary visual cortex in mouse, we found that SANPCs co-clustered with cortical neurons. Tissue and cellular imaging confirmed that SANPCs contained key elements of glutamatergic neurotransmitter system, expressing genes encoding glutamate synthesis pathway (Gls), ionotropic and metabotropic glutamate receptors (Grina, Gria3, Grm1 and Grm5), and glutamate transporters (Slc17a7). SANPCs highly expressed cell markers of glutamatergic neurons (Snap25 and Slc17a7), whereas Gad1, a marker of GABAergic neurons, was negative. Functional studies revealed that inhibition of glutamate receptors or transporters reduced spontaneous pacing frequency of isolated SAN tissues and spontaneous Ca