Low intensity pulsed ultrasound ameliorates Adriamycin-induced chronic renal injury by inhibiting ferroptosis.

OBJECTIVE: It is very important to develop a new therapeutic strategy to cope with the increasing morbidity and mortality of chronic kidney disease (CKD). As a kind of physical therapy, low intensity pulsed ultrasound (LIPUS) has remarkable anti-inflammatory and repair-promoting effects and is expected to become a new therapeutic method for CKD. This study aims to clarify the treatment effect of LIPUS on CKD-related renal inflammation and fibrosis, and to further explore the potential signal network of LIPUS treatment for ameliorating chronic renal injury. METHODS: A rat model simulating the progress of CKD was established by twice tail-vein injection of Adriamycin (ADR). Under anesthesia, bilateral kidneys of CKD rats were continuously stimulated by LIPUS for four weeks. The parameters of LIPUS were 1.0 MHz, 60 mW/cm2, 50% duty cycle and 20 min/d. RESULTS: LIPUS treatment effectively inhibited ADR-induced renal inflammation and fibrosis, and improved CKD-related to oxidative stress and ferroptosis. In addition, the therapeutic effect of LIPUS is closely related to the regulation of TGF-ß1/Smad and Nrf2/keap1/HO-1 signalling pathways. DISCUSSION: This study provides a new direction for further mechanism research and lays an important foundation for clinical trials.

[Effects of integrin on differentiation of mesenchymal stem cells].

Integrin is a family of transmembrane heterodimer receptor formed by α and ß two subunits, which transduces external signals into cells through reaction with extracellular matrix and is crucial to cell survival, migration, and differentiation. With the deep studies on multipotential differentiation of mesenchymal stem cells (MSCs), researchers found that the differentiation of MSCs depends on integrin related signaling pathways, including MAPK, Wnt and PI3K signaling pathways and so on. However, there are many factors affecting the expression and activation of integrin, such as nano morphology microenvironment, ascorbic acid, bone morphogenetic protein-2, fibronectin, cadherin, fluid shear stress and so on. In this review, we mainly discuss the integrin expression, the promoting effects of integrin on the differentiation of MSCs and their underlying mechanisms.

Effect of aspirin on high glucose-induced senescence of endothelial cells.

BACKGROUND: Endothelial cell senescence is accelerated under high glucose condition, which may contribute to the vascular complications in the diabetics. It has been proved that aspirin has multiple cytoprotective effects. This study aimed to investigate the effect of aspirin on high glucose-induced endothelial cell senescence and its possible mechanism. METHODS: Human umbilical venous endothelial cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with different treatments including the normal glucose (5.5 mmol/L), high glucose (33 mmol/L) and aspirin (0.01 - 1.00 mmol/L) with high glucose. And 300 micromol/L L-NAME was added to the culture medium when needed. After 48 hours, SA-beta-gal staining was used to evaluate the senescence. Total nitric oxide (NO) production and NO synthase (NOS) activity were measured using Griess reaction and molecular probes of 3-amino-4-aminomethyl-2', 7'-difluorescein, diacetate. The level of intracellular reactive oxygen species was monitored by flow cytometry using 2', 7'-dichlorofluorescein diacetate. Endothelial NOS (eNOS), caveolin-1 protein expressions and caveolin-1/eNOS interaction were analyzed by immunoblotting and immunoprecipitation respectively. Asymmetric dimethylarginine (ADMA) concentration was determined by high-performance liquid chromatography. RESULTS: Exposure to 33 mmol/L glucose for 48 hours significantly increased the number of SA-beta-gal positive cells. Co-incubation with aspirin markedly inhibited SA-beta-gal activity dose-dependently. Aspirin increased NOS activity with eNOS protein expression unchanged and increased NO levels and alleviated oxidative stress. Consistent with these findings, caveolin-1 expression, caveolin-1/eNOS interaction and ADMA accumulation were also decreased. All the inhibitory effects of aspirin on senescence were completely obliterated by L-NAME, the NOS inhibitor. CONCLUSION: The anti-senescent effects of aspirin are fulfilled by increasing NO production via the up-regulation of NOS activity and preventing caveolin-1 expression, caveolin-1/eNOS interaction and ADMA accumulation.

Apoptosis is involved in the senescence of endothelial cells induced by angiotensin II.

Vascular endothelial cells have a finite cell lifespan and eventually enter an irreversible growth arrest, cellular senescence. The functional changes associated with cellular senescence are thought to contribute to human aging and age-related cardiovascular disorders, e.g. atherosclerosis. In this study, induction of Angiotensin II (Ang II) promoted a growth arrest with phenotypic characteristics of cell senescence, such as enlarged cell shapes, increased senescence-associated beta-galactosidase (SA-beta-gal) positive staining cell, and depressed cell proliferation. Apoptotic changes were increased in senescent cells, with a small subset of the senescent cells showing aberrant morphology such as pronounced nuclear fragmentation or multiple micronuclei. The results suggest cell apoptosis is possibly an important factor in the process of pathologic and physiologic senescence of endothelial cells as well as vascular aging.