Intracellular localization of polymyxins in human alveolar epithelial cells.

Background: Current inhaled polymyxin therapy is empirical and often large doses are administered, which can lead to pulmonary adverse effects. There is a dearth of information on the mechanisms of polymyxin-induced lung toxicity and their intracellular localization in lung epithelial cells.

Objectives: To investigate the intracellular localization of polymyxins in human lung epithelial A549 cells.

Deoxyribonuclease 1 reduces pathogenic effects of cigarette smoke exposure in the lung.

Our aim was to investigate if deoxyribonuclease (DNase) 1 is a potential therapeutic agent to reduce pathogenic effects of cigarette smoke exposure in the lung. Cigarette smoke causes protease imbalance with excess production of proteases, which is a key process in the pathogenesis of emphysema. The mechanisms responsible for this effect are not well-defined.

Nontypeable Haemophilus influenzae induces sustained lung oxidative stress and protease expression.

Nontypeable Haemophilus influenzae (NTHi) is a prevalent bacterium found in a variety of chronic respiratory diseases. The role of this bacterium in the pathogenesis of lung inflammation is not well defined. In this study we examined the effect of NTHi on two important lung inflammatory processes 1), oxidative stress and 2), protease expression.

The directed differentiation of human iPS cells into kidney podocytes.

The loss of glomerular podocytes is a key event in the progression of chronic kidney disease resulting in proteinuria and declining function. Podocytes are slow cycling cells that are considered terminally differentiated. Here we provide the first report of the directed differentiation of induced pluripotent stem (iPS) cells to generate kidney cells with podocyte features.

The functions of Mediator in Candida albicans support a role in shaping species-specific gene expression.

The Mediator complex is an essential co-regulator of RNA polymerase II that is conserved throughout eukaryotes. Here we present the first study of Mediator in the pathogenic fungus Candida albicans. We focused on the Middle domain subunit Med31, the Head domain subunit Med20, and Srb9/Med13 from the Kinase domain.

Stress-induced synthesis of phosphatidylinositol 3-phosphate in mycobacteria.

Phosphoinositides play key roles in regulating membrane dynamics and intracellular signaling in eukaryotic cells. However, comparable lipid-based signaling pathways have not been identified in bacteria. Here we show that Mycobacterium smegmatis and other Actinomycetes bacteria can synthesize the phosphoinositide, phosphatidylinositol 3-phosphate (PI3P).

A high-resolution solution structure of a trypanosomatid FYVE domain.

FYVE domain proteins play key roles in regulating membrane traffic in eukaryotic cells. The FYVE domain displays a remarkable specificity for the head group of the target lipid, phosphatidylinositol 3-phosphate (PtdIns[3]P). We have identified five putative FYVE domain proteins in the genome of the protozoan parasite Leishmania major, three of which are predicted to contain a functional PtdIns(3)P-binding site.

Serum amyloid P colocalizes with apolipoproteins in human atheroma: functional implications.

Serum amyloid P (SAP) is a common component of human amyloid deposits and has been identified in atherosclerotic lesions. We investigated the extent of the colocalization of SAP with apolipoprotein A-I (apoA-I), apoB, apoC-II, and apoE in human coronary arteries and explored potential roles for SAP in these regions, specifically the effect of SAP on the rate of formation and macrophage recognition of amyloid fibrils composed of apoC-II. Analysis of 42 human arterial sections by immunohistochemistry and double label fluorescence microscopy demonstrated that SAP and apoA-I, apoB, apoC-II, and apoE were increased significantly in atherosclerotic lesions compared with nonatherosclerotic segments.

SMP-1, a member of a new family of small myristoylated proteins in kinetoplastid parasites, is targeted to the flagellum membrane in Leishmania.

The mechanisms by which proteins are targeted to the membrane of eukaryotic flagella and cilia are largely uncharacterized. We have identified a new family of small myristoylated proteins (SMPs) that are present in Leishmania spp and related trypanosomatid parasites. One of these proteins, termed SMP-1, is targeted to the Leishmania flagellum.

Evidence that intracellular beta1-2 mannan is a virulence factor in Leishmania parasites.

The protozoan parasite Leishmania mexicana proliferates within macrophage phagolysosomes in the mammalian host. In this study we provide evidence that a novel class of intracellular beta1-2 mannan oligosaccharides is important for parasite survival in host macrophages. Mannan (degree of polymerization 4-40) is expressed at low levels in non-pathogenic promastigote stages but constitutes 80 and 90% of the cellular carbohydrate in the two developmental stages that infect macrophages, non-dividing promastigotes, and lesion-derived amastigotes, respectively.

The small GTPase Rab22 interacts with EEA1 and controls endosomal membrane trafficking.

Rab22a is a small GTPase that is expressed ubiquitously in mammalian tissues and displays the highest sequence homology to Rab5. In BHK-21 cells, overexpression of the wild-type Rab22a caused formation of abnormally large vacuole-like structures containing the early-endosomal antigen EEA1 but not Rab11, a marker of recycling endosomes or the late-endosomal/lysosomal markers LAMP-1 and lyso-bis-phosphatidic acid. In HeLa cells, overexpressed Rab22a was found on smaller EEA1-positive endosomes, but a portion of the protein was also found in the Golgi complex.