Membrane Dynamics Regulated by Cytoskeleton in Plant Immunity.

The plasma membrane (PM), which is composed of a lipid layer implanted with proteins, has diverse functions in plant responses to environmental triggers. The heterogenous dynamics of lipids and proteins in the plasma membrane play important roles in regulating cellular activities with an intricate pathway that orchestrates reception, signal transduction and appropriate response in the plant immune system. In the process of the plasma membrane participating in defense responses, the cytoskeletal elements have important functions in a variety of ways, including regulation of protein and lipid dynamics as well as vesicle trafficking. In this review, we summarized how the plasma membrane contributed to plant immunity and focused on the dynamic process of cytoskeleton regulation of endocytosis and exocytosis and propose future research directions.

Using Drosophila Nephrocytes to Understand the Formation and Maintenance of the Podocyte Slit Diaphragm.

The podocyte slit diaphragm (SD) is an essential component of the glomerular filtration barrier and its disruption is a common cause of proteinuria and many types of kidney disease. Therefore, better understanding of the pathways and proteins that play key roles in SD formation and maintenance has been of great interest. Podocyte and SD biology have been mainly studied using mouse and other vertebrate models. However, vertebrates are limited by inherent properties and technically challenging in vivo access to the podocytes. Drosophila is a relatively new alternative model system but it has already made great strides. Past the initial obvious differences, mammalian podocytes and fly nephrocytes are remarkably similar at the genetic, molecular and functional levels. This review discusses SD formation and maintenance, and their dependence on cell polarity, the cytoskeleton, and endo- and exocytosis, as learned from studies in fly nephrocytes and mammalian podocytes. In addition, it reflects on the remaining gaps in our knowledge, the physiological implications for glomerular diseases and how we can leverage the advantages Drosophila has to offer to further our understanding.

The effect of pH and ligand density on the endocytosis and exocytosis process of FcBP decorated PEG-PCL micelles on Caco-2 cells / 药学学报

The difference in pH between apical and basolateral side of intestinal epithelial and pH dependence character of the combination of FcRn (neonatal Fc receptor) and ligand might improve the delivery of hydrophobic drugs by facilitating the transcytosis of nanocarriers. Here we designed FcBP (IgG Fc domain-binding peptides) decorated coumarin 6 (C6) loaded poly(ethyl ethylene phosphate)-co-poly(ε-caprolactone) (PEG-PCL) micelles with different ligand densities to study the effect of pH and ligand density on the endocytosis and exocytosis process of micelles on human colon adenanocaricinoma cell lines (Caco-2). Active micelles with different ligand densities and passive micelles were prepared using the thin-film hydration method. The size of the micelles was characterized by dynamic light scattering analysis and the morphology was observed by transmission electron microscope. The endocytosis and exocytosis of the micelles at pH 7.4 and pH 6.0, as well as the effect of FcRn on the endocytosis, were investigated by flow cytometry. The results showed that the size of micelles was about 30 nm, which was not affected by FcBP decoration. We found that pH and ligand density could both influence the endocytosis. The uptake of active micelles was higher at pH 6.0 than at pH 7.4, and an optimal ligand density of endocytosis was appeared in both pH environment. Then we proved that FcBP decorated micelles could be endocytosed at pH 6.0 and exocytosed at pH 7.4, and the exocytosis process was also related to ligand density. Micelles with 10% ligand density had the largest exocytosis, showing the potentiality to deliver drugs through the intestinal epithelial. In addition, the competitive inhibition experiments illustrated that the interaction between FcRn and FcBP were essential to endocytosis. The results will enhance the understanding on the FcBP decorated PEG-PCL micelles for transmemberane drug delivery.