The complexing of cationic copolymer MPC30-DEA70 with TGF-ß1 antisense oligodeoxynucleotide and transfection into cardiomyocytes in vitro.

Although gene therapy is an attractive option for the treatment of cardiovascular diseases, the ideal gene delivery systems are still under investigation and must meet the following criteria: safety, adequate gene transfer efficiency, and stable expression of the transgene for a duration appropriate for treating the disease. In this study, we developed a cationic phosphorylcholine-containing diblock copolymer, namely MPC30-DEA70, as carrier systems to deliver a chemically synthesized transforming growth factor-beta 1(TGF-ß1) antisense oligonucleotide (AS-ODN) into cardiomyocytes (CMs) to observe the cell transfection efficiency of MPC30-DEA70 and the inhibition effect on the expression of TGF-ß1. MPC30-DEA70/TGF-ß1 AS-ODN complexes were formed through complexation between copolymer MPC30-DEA70 (N) and AS-ODN (P) at different N/P ratios and were characterized by DNA electrophoresis. Notably, the cytotoxicity and cell growth inhibition assay showed that the MPC30-DEA70 had low cytotoxicity to CMs within the effective transfection dosage range (<20 µL/mL). CLSM/TEM images displayed that most of the AS-ODN molecules engulfed by cells were located around the cell nuclei, and a few entered into the cell nuclei without harming the organelles in the cell. Transfection studies from CMs indicated a steady increase of transfection efficiency with increasing N/P ratios. The expression levels of TGF-ß1 mRNA and protein in CMs were significantly inhibited at high N/P ratios. This study shows that MPC30-DEA70 can function as an effective transgenic vector into CMs and that TGF-ß1 AS-ODN delivered by MPC30-DEA70 can silence the expression of the TGF-ß1 gene efficiently and specifically and thereafter antagonize TGF-ß1-mediated biological function in cardiomyocytes.

FERONIA receptor kinase-regulated reactive oxygen species mediate self-incompatibility in Brassica rapa.

Most plants in the Brassicaceae evolve self-incompatibility (SI) to avoid inbreeding and generate hybrid vigor. Self-pollen is recognized by the S-haplotype-specific interaction of the pollen ligand S-locus protein 11 (SP11) (also known as S-locus cysteine-rich protein [SCR]) and its stigma-specific S-locus receptor kinase (SRK). However, mechanistically much remains unknown about the signaling events that culminate in self-pollen rejection. Here, we show that self-pollen triggers high levels of reactive oxygen species (ROS) in stigma papilla cells to mediate SI in heading Chinese cabbage (Brassica rapa L. ssp. pekinensis). We found that stigmatic ROS increased after self-pollination but decreased after compatible(CP)- pollination. Reducing stigmatic ROS by scavengers or suppressing the expression of respiratory burst oxidase homologs (Rbohs), which encode plant NADPH oxidases that produce ROS, both broke down SI. On the other hand, increasing the level of ROS inhibited the germination and penetration of compatible pollen on the stigma, mimicking an incompatible response. Furthermore, suppressing a B. rapa FERONIA (FER) receptor kinase homolog or Rac/Rop guanosine triphosphatase (GTPase) signaling effectively reduced stigmatic ROS and interfered with SI. Our results suggest that FER-Rac/Rop signaling-regulated, NADPH oxidase-produced ROS is an essential SI response leading to self-pollen rejection.

BDNF mechanisms in late LTP formation: A synthesis and breakdown.

Unraveling the molecular mechanisms governing long-term synaptic plasticity is a key to understanding how the brain stores information in neural circuits and adapts to a changing environment. Brain-derived neurotrophic factor (BDNF) has emerged as a regulator of stable, late phase long-term potentiation (L-LTP) at excitatory glutamatergic synapses in the adult brain. However, the mechanisms by which BDNF triggers L-LTP are controversial. Here, we distill and discuss the latest advances along three main lines: 1) TrkB receptor-coupled translational control underlying dendritic protein synthesis and L-LTP, 2) Mechanisms for BDNF-induced rescue of L-LTP when protein synthesis is blocked, and 3) BDNF-TrkB regulation of actin cytoskeletal dynamics in dendritic spines. Finally, we explore the inter-relationships between BDNF-regulated mechanisms, how these mechanisms contribute to different forms of L-LTP in the hippocampus and dentate gyrus, and outline outstanding issues for future research. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.