Endosomal regulation of contact inhibition through the AMOT:YAP pathway.

Contact-mediated inhibition of cell proliferation is an essential part of organ growth control; the transcription coactivator Yes-associated protein (YAP) plays a pivotal role in this process. In addition to phosphorylation-dependent regulation of YAP, the integral membrane protein angiomotin (AMOT) and AMOT family members control YAP through direct binding. Here we report that regulation of YAP activity occurs at the endosomal membrane through a dynamic interaction of AMOT with an endosomal integral membrane protein, endotubin (EDTB).

Regulation of tight junction assembly and epithelial polarity by a resident protein of apical endosomes.

The establishment of tight junctions and cell polarity is an essential process in all epithelia. Endotubin is an integral membrane protein found in apical endosomes of developing epithelia when tight junctions and epithelial polarity first arise. We found that the disruption of endotubin function in cells in culture by siRNA or overexpression of the C-terminal cytoplasmic domain of endotubin causes defects in organization and function of tight junctions.

Prevention of LPS-induced acute lung injury in mice by mesenchymal stem cells overexpressing angiopoietin 1.

Background: The acute respiratory distress syndrome (ARDS), a clinical complication of severe acute lung injury (ALI) in humans, is a leading cause of morbidity and mortality in critically ill patients. ALI is characterized by disruption of the lung alveolar-capillary membrane barrier and resultant pulmonary edema associated with a proteinaceous alveolar exudate. Current specific treatment strategies for ALI/ARDS are lacking.

Cell-based angiopoietin-1 gene therapy for acute lung injury.

Rationale: The acute respiratory distress syndrome is a significant cause of morbidity and mortality in critically ill patients. Angiopoietin-1 (Ang-1), a ligand for the endothelial Tie2 receptor, is an endothelial survival and vascular stabilization factor that reduces endothelial permeability and inhibits leukocyte-endothelium interactions.

Objectives: We hypothesized that Ang-1 counteracts vascular inflammation and pulmonary vascular leak in experimental acute lung injury.

Regulation of endothelin-1 by angiopoietin-1: implications for inflammation.

Endothelin-1 (ET-1) is increasingly recognized as a proinflammatory mediator in various diseases, such as atherosclerosis and acute respiratory distress syndrome (ARDS). Angiopoietin-1 (Ang-1), a ligand of the endothelial receptor Tie2, inhibits endothelial apoptosis, reduces vascular leakage, and suppresses the induction of inflammatory markers, indicating that it has diverse vasoprotective, anti-inflammatory actions. Thus, we examined the effects of Ang-1 on ET-1 production in vitro and in vivo and investigated cell-based gene transfer of Ang-1 in a rat model of lipopolysaccharide (LPS)-induced ARDS.

Chronic lower extremity ischemia: a human model of ischemic tolerance.

Background: Ischemic preconditioning (IPC) has been found in animals to have a protective effect against future ischemic injury to muscle tissue. Such injury is unavoidable during some surgical procedures. To determine whether chronic ischemia in the lower extremities would imitate IPC and reduce ischemic injury during vascular surgery, we designed a controlled clinical study.

Remote liver injury is attenuated by adenovirus-mediated gene transfer of heme oxygenase-1 during the systemic inflammatory response syndrome.

Objectives: Adenovirus-mediated gene therapy is being investigated with increasing success for future treatment of autoimmune diseases. However, the use of adenoviruses is still limited by inflammatory and immune responses in the target organ. Previous work by the authors' laboratory established that the adenovirus encoding inducible heme oxygenase (Ad-HO-1) does not elicit the acute hepatic inflammation normally caused by adenoviruses, inviting further investigation in models of severe inflammation.

Endogenous heme oxygenase induction is a critical mechanism attenuating apoptosis and restoring microvascular perfusion following limb ischemia/reperfusion.

Background: A protective role for endogenous heme oxygenase (HO) in the initiation of remote liver injury after limb ischemia/reperfusion has been established. This study expands on our previous work by investigating the role of endogenous HO on hepatocellular injury, hepatocyte death (necrotic and apoptotic), and microvascular perfusion at protracted post-reperfusion times.

Methods: Remote liver injury was studied after 1 hour of bilateral hind limb ischemia and 3, 6, or 24 hours of reperfusion in male C57BL6 mice.

Limitations of ischemic tolerance in oxidative skeletal muscle: perfusion vs tissue protection.

Objectives: This study determined if ischemic tolerance occurs in oxidative skeletal muscle following a severe ischemia/reperfusion (I/R) insult and if such protection involves the induction of nitric oxide synthase (NOS).

Methods: The soleus muscle of male Wistar rats (250-350 g) was preconditioned (PC + I/R) using five cycles of ischemia (10 min) and reperfusion (10 min) or had no PC (I/R) and 24 h later 2 h no-flow ischemia was induced. Calcium dependent (cNOS) and independent (iNOS) NOS activities were determined from PC (n = 5), or sham (n = 5) and the role of iNOS was tested by application of aminoguanidine (AMG) (100 microM; n = 4) to the muscle bath.

Inhibition of haem oxygenase activity increases leukocyte accumulation in the liver following limb ischaemia-reperfusion in mice.

The role of haem oxygenase (HO) in the hepatic accumulation of leukocytes in mice during the initiation of remote organ injury following normotensive limb ischaemia-reperfusion (I-R) was investigated. Remote organ injury was initiated by 1 h bilateral hindlimb ischaemia followed by either 1 or 1.5 h reperfusion (I-R) in male C57BL/6 mice.

The role of endogenous heme oxygenase in the initiation of liver injury following limb ischemia/reperfusion.

Background/aims: Heme oxygenase (HO) derived liver protection was tested in mice following 1 h bilateral hindlimb ischemia and either 1.5 or 3 h reperfusion.

Methods: Groups consisted of limb ischemia/reperfusion (I/R), sham (no I/R), I/R+chromium mesoporphyrin (I/R+CrMP;40 micromol/kg, i.