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Glucagon-like peptide 1 (GLP-1) analogs are used to treat type 2 diabetes, and they can regulate insulin secretion, energy homeostasis, inflammation, and immune cell function. This study sought to determine whether the GLP-1 analog liraglutide exerts a beneficial action in an acute lung injury model of pneumonia-induced sepsis. Methods:Wild-type FVB/NJ mice (n = 114) were infected by intratracheal injection with Pseudomonas aeruginosaXen5 (4 × 104CFU/mouse) or an equal volume (50 μL) of saline (control) with or without a subcutaneous injection of liraglutide (2 mg/kg, 30 min after infection). Mice were killed 24 h after infection. Lung tissues and BALF were analyzed. In separate experiments, the dynamic growth of bacteria and animal mortality was monitored using in vivoimaging system within 48 h after infection. In addition, primary lung alveolar type II cells isolated from mice were used to study the mechanism of liraglutide action. Result:Liraglutide improved survival (P< 0.05), decreased bacterial loads in vivo, and reduced lung injury scores (P< 0.01) in septic mice. Liraglutide-treated mice showed decreased levels of inflammatory cells (P< 0.01) and proinflammatory cytokines (TNF-α and IL-6) (P< 0.01) in the lung compared with septic controls. Liraglutide significantly increased pulmonary surfactant proteins (SP-A and SP-B) expression/secretion (P< 0.01) and phospholipid secretion (P< 0.01) in vivo. Primary alveolar type II cells pretreated with liraglutide improved SP-A and SP-B expression after LPS exposure (P< 0.01). Conclusion:Liraglutide attenuates mortality and lung inflammation/injury in pneumonia-induced sepsis. The increased surfactant expression/secretion and anti-inflammatory effects of liraglutide represent potential mechanisms by GLP-1 agonists potentiate host defense and maintain alveolar respiratory function in acute lung injury.

ABSTRACTBackground:Deposition of various crystal and organic substances in the kidney can lead to kidney stone formation. Melatonin is an effective endogenous antioxidant that can prevent crystalluria and kidney damage due to crystal formation and aggregation. In this study, we investigated the mechanism by which melatonin inhibits endoplasmic reticulum (ER) stress and apoptosis.Methods:We treated HK-2 cells with oxalate to establish an in vitrokidney stone model, and treated these cells with different concentrations of melatonin (0, 5, 10, 20 μmol/L) and the AMP-activated protein kinase (AMPK) inhibitor Compound C. We measured levels of stress response markers including reactive oxygen species (ROS), lactate dehydrogenase (LDH), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and factors in the stress response pathway, such as ATF6, GRP78, DDIT3, PERK, p-PERK, IRE1, p-IRE1, XBP1s, AMPK, and p-AMPK, using real time-PCR, western blot, and immunofluorescence analyzes. We measured mitochondrial membrane potential and caspases-3 activity using the CCK8, enzyme-linked immunosorbent, and flow cytometry assays to assess HK-2 cell viability and apoptosis.Results:Melatonin improved the total antioxidant capacity (T-AOC) of the HK-2 cells, as evidenced by the dose-dependent reduction in apoptosis, ROS levels, and protein expression of ATF6, GRP78, DDIT3, p-PERK, p-IRE1, XBP1s, caspase-12, cleaved caspase-3 and cleaved caspase-9. Addition of the AMPK inhibitor, Compound C, partially reversed the protective effect of melatonin.Conclusion:Our study revealed that the protective effects of melatonin on oxalate-induced ER stress and apoptosis is partly dependent on AMPK activation in HK-2 cells. These findings provide insight into the prevention and treatment of kidney stones.

Ileal conduits are commonly used in bladder cancer treatment and in pediatric patients who require urinary diversion surgeries. We constructed a tissue-engineered conduit using bone marrow mesenchymal stem cells (BMSCs) and a bladder acellular matrix (BAM) and transplanted it into rabbits for urinary diversion to evaluate the feasibility of its clinical application. Rabbit BMSCs were isolated, expanded in vitro, and were then treated with a conditional medium for 3 weeks, allowing the BMSCs to transform into urothelium-like cells. These cells were seeded onto BAM and cultured for another week. The cell-matrix grafts were then sewn into a conduit approximately 4 cm in length and 1 cm in diameter and were implanted as conduits for urinary diversion in 12 male rabbits. Rabbits were sacrificed at 1, 2, and 4 week after operation. Histologic examinations were performed using hematoxylin and eosin staining and tissue structures were evaluated by using immunohistochemistry. BMSCs can transform into urothelium-like cells that express the urothelium-specific proteins uroplakin 1A (UPK1A), cytokeratin 7 (CK7), and cytokeratin 13 (CK13). These cells are able to generate epithelial coverage in the conduit lumen based on BAM. Immunohistochemistry showed positive staining with AE1/AE3, UPK1A, and tight junction protein 1 (ZO-1), indicating the presence of mature and functional epithelial cells on the lumen of the conduit. BMSCs may represent a new source cell for urinary tissue engineering, and it is feasible to construct a conduit with transformed BMSCs and BAM for urinary diversion in rabbits.