Circulating small extracellular vesicles mediate vascular hyperpermeability in diabetes.

Aims/hypothesis: A hallmark chronic complication of type 2 diabetes mellitus is vascular hyperpermeability, which encompasses dysfunction of the cerebrovascular endothelium and the subsequent development of associated cognitive impairment. The present study tested the hypothesis that during type 2 diabetes circulating small extracellular vesicles (sEVs) exhibit phenotypic changes that facilitate pathogenic disruption of the vascular barrier.

Methods: sEVs isolated from the plasma of a mouse model of type 2 diabetes and from diabetic human individuals were characterised for their ability to disrupt the endothelial cell (EC) barrier.

Neuronal hypertrophy dampens neuronal intrinsic excitability and stress responsiveness during chronic stress.

Key Points: The hypothalamic-pituitary-adrenal (HPA) axis habituates to repeated stress exposure. We studied hypothalamic corticotropin-releasing hormone (CRH) neurons that form the apex of the HPA axis in a mouse model of stress habituation using repeated restraint. The intrinsic excitability of CRH neurons decreased after repeated stress in a time course that coincided with the development of HPA axis habituation.

Syntaxin-3 is dispensable for basal neurotransmission and synaptic plasticity in postsynaptic hippocampal CA1 neurons.

Recent evidence suggests that SNARE fusion machinery play critical roles in postsynaptic neurotransmitter receptor trafficking, which is essential for synaptic plasticity. However, the key SNAREs involved remain highly controversial; syntaxin-3 and syntaxin-4 are leading candidates for the syntaxin isoform underlying postsynaptic plasticity. In a previous study, we showed that pyramidal-neuron specific conditional knockout (cKO) of syntaxin-4 significantly reduces basal transmission, synaptic plasticity and impairs postsynaptic receptor trafficking.

Extracellular phosphorylation drives the formation of neuronal circuitry.

Until recently, the existence of extracellular kinase activity was questioned. Many proteins of the central nervous system are targeted, but it remains unknown whether, or how, extracellular phosphorylation influences brain development. Here we show that the tyrosine kinase vertebrate lonesome kinase (VLK), which is secreted by projecting retinal ganglion cells, phosphorylates the extracellular protein repulsive guidance molecule b (RGMb) in a dorsal-ventral descending gradient.

Expansion of CD25+CD4+ regulatory T cells by natural mature dendritic cells.

Because of the anergy of CD25+CD4+ regulatory T cells, it is unclear how the number of these regulatory T cells is sustained and expanded in normal physiologic circumstances. In the present study, we examined the effect of natural allogeneic mature dendritic cells (DCs) on the proliferation and function of CD25+CD4+ T cells. Our data showed that natural allogeneic mature DCs stimulated CD25+CD4+ T-cell growth vigorously, whereas immature DCs had little effect on the proliferation of CD25+CD4+ T cells.

Transplant long-surviving induced by CD40-CD40 ligand costimulation blockade is dependent on IFN-γ through its effect on CD4(+)CD25(+) regulatory T cells.

Background: IFN-γ was documented to be commonly associated with acute rejection. In the present study, we investigated the role of IFN-γ in the transplant long-surviving induced by blocking CD40-CD40 ligand (CD40-CD40L) costimulation and its mechanisms.

Methods: IFN-γ expression in cardiac allografts and spleens from syngeneic and allogeneic recipients with or without anti-CD40L monoclonal antibody (MR-1) treatment was examined by real-time RT-PCR.

CD40-CD40L costimulation blockade induced the tolerogenic dendritic cells in mouse cardiac transplant.

We aimed to investigate whether tolerogenic dendritic cells (DCs) were induced in the tolerant recipients with the blockade of CD40-CD40L costimulation. Mouse heterotopic heart transplantation was performed. DCs were sorted from rejected and tolerant recipients using magnetic-activated cell sorting.