title: Lung endothelial cell apoptosis during ischemic acute kidney injury.
abstract: Kidney ischemia-reperfusion injury (IRI) activates cellular and soluble mediators that drive lung inflammatory cascades, tumor necrosis factor receptor 1 (TNFR1)-mediated programmed cell death, and microvascular barrier dysfunction, leading to acute lung injury. We hypothesized that lung microvascular endothelial cells (ECs), with their integral role in maintaining the lung-semipermeable barrier, were key cellular targets of TNFR1-mediated apoptosis during ischemic AKI. Male C57/BL6 mice and Sprague-Dawley rats underwent 60 min of bilateral renal pedicle occlusion (IRI) or sham laparotomy (sham) and were killed at 4 or 24 h. Colocalization with TUNEL, DAPI, and CD34 was performed to identify EC-specific apoptosis. Mouse ECs (CD45/CD31) isolated with novel tissue digestion techniques and magnetic microbead sorting underwent quantitative real-time polymerase chain reaction SuperArray analysis with 84 apoptosis-related genes. In parallel, rat lung microvascular ECs grown to confluence were treated with serum from rats obtained following sham or kidney IRI. Rat lung microvascular ECs treated +/- etanercept, a TNF-α/TNFR1 signaling inhibitor, underwent custom real-time polymerase chain reaction analysis for proapoptotic and TNF superfamily transcriptional events, and apoptosis was identified with caspase 3 and poly(ADP-ribose) polymerase activity assays. In vivo, TUNEL-positive cells colocalized with CD34 in whole-lung tissue and isolated lung ECs demonstrated a proapoptotic transcriptome during ischemic AKI. In vitro, ischemic AKI incited proapoptotic (FasL, Dapk1, Bcl10) and TNF superfamily (TNFR1, TNFR2, TNF-α) gene activation and increased caspase 3 and poly(ADP-ribose) polymerase activity at 24 h versus sham. Compared with vehicle, treatment of rat lung microvascular ECs with etanercept inhibited proinflammatory gene activation (E-selectin, intercellular adhesion molecule 1, interleukin 6, RhoB) and apoptosis during ischemic AKI. Ischemic AKI drives distinct proinflammatory and proapoptotic changes in the pulmonary EC transcriptome with TNFR1-dependent caspase activation and programmed cell death. Further investigation of potential EC mechanisms of kidney-lung crosstalk during AKI may identify potential therapeutic targets for this deadly disease.
authors: Department of Surgery, The Methodist Hospital and Research Institute, Houston, TX 77030, USA.
authors: Laura E
authors: LE
authors: White
authors: Yan
authors: Y
authors: Cui
authors: Carolyn M Feltes
authors: CM
authors: Shelak
authors: Mihaela L
authors: ML
authors: Lie
authors: Heitham T
authors: HT
authors: Hassoun
mesh_terms: D058186:Acute Kidney Injury / Q000503:physiopathology*; D055371:Acute Lung Injury / Q000235:genetics / Q000503:physiopathology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology*; D000068800:Etanercept; D007074:Immunoglobulin G / Q000494:pharmacology; D008168:Lung / Q000098:blood supply; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D055806:Microvessels / Q000502:physiology; D011014:Pneumonia / Q000235:genetics / Q000503:physiopathology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000502:physiology; D015427:Reperfusion Injury / Q000235:genetics / Q000503:physiopathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D000068800:Etanercept