Blood brain barrier (BBB) disruption occurs early enough to be within the thrombolytic time window, and this early ischemic BBB damage is closely associated with hemorrhagic transformation and thus emerging as a promising target for reducing the hemorrhagic complications of thrombolytic stroke therapy. However, the mechanisms underlying early ischemic BBB damage remain poorly understood. Here we investigated the early molecular events of ischemic BBB damage using in vitro oxygen-glucose deprivation (OGD) and in vivo rat middle cerebral artery occlusion (MCAO) models. Exposure of bEND3 monolayer to OGD for 2 h significantly increased its permeability to FITC-labeled dextran, and promoted the secretion of metalloproteinase-2 and 9 (MMP-2/9) and cytosolic translocation of caveolin-1 (Cav-1). This same OGD treatment also led to rapid degradation of tight junction protein occludin and dissociation of claudin-5 from the cytoskeleton, which contributed to OGD-induced endothelial barrier disruption. Using selective MMP-2/9 inhibitor SB-3CT or their neutralizing antibodies or Cav-1 siRNA, we found that MMP-2 was the major enzyme mediating OGD-induced occludin degradation, while Cav-1 was responsible for claudin-5 redistribution. The interaction between Cav-1 and claudin-5 was further confirmed by coimmunoprecipitation. Consistent with these in vitro findings, we observed fluorescence tracer extravasation, increased gelatinolytic activity and elevated interstitial MMP-2 levels in ischemic subcortical tissue after 2-h MCAO. Moreover, occludin protein loss and claudin-5 redistribution were detected in ischemic cerebromicrovessels. These data indicate that cerebral ischemia initiates two rapid parallel processes, MMP-2-mediated occludin degradation and Cav-1-mediated claudin-5 redistribution, to cause BBB disruption at early stroke stages relevant to acute thrombolysis.

The alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) typically engage in chemical bonding as classical main-group elements through their s andp valence orbitals, where is the principal quantum number. Here we report the isolation and spectroscopic characterization of eight-coordinate carbonyl complexes M(CO) (where M = Ca, Sr, or Ba) in a low-temperature neon matrix. Analysis of the electronic structure of these cubic -symmetric complexes reveals that the metal-carbon monoxide (CO) bonds arise mainly from [M(d)] → (CO) π backdonation, which explains the strong observed red shift of the C-O stretching frequencies. The corresponding radical cation complexes were also prepared in gas phase and characterized by mass-selected infrared photodissociation spectroscopy, confirming adherence to the 18-electron rule more conventionally associated with transition metal chemistry.

There are three major dendritic cell (DC) subsets in both humans and mice, that is, plasmacytoid DCs and two types of conventional DCs (cDCs), cDC1s and cDC2s. cDC2s are important for polarizing CD4 naive T cells into different subsets, including Th1, Th2, Th17, Th22, and regulatory T cells. In mice, cDC2s can be further divided into phenotypically and functionally distinct subgroups. However, subsets of human cDC2s have not been reported. In the present study, we showed that human blood CD1c cDCs (cDC2s) can be further separated into two subpopulations according to their CD5 expression status. Comparative transcriptome analyses showed that the CD5 DCs expressed higher levels of cDC2-specific genes, including IFN regulatory factor 4, which is essential for the cDC2 development and its migration to lymph nodes. In contrast, CD5 DCs preferentially expressed monocyte-related genes, including the lineage-specific transcription factor MAFB. Furthermore, compared with the CD5 subpopulation, the CD5 subpopulation showed stronger migration toward CCL21 and overrepresentation among migratory DCs in lymph nodes. Additionally, the CD5 DCs induced naive T cell proliferation more potently than did the CD5 DCs. Moreover, CD5 DCs induced higher levels of IL-10-, IL-22-, and IL-4-producing T cell formation, whereas CD5 DCs induced higher levels of IFN-γ-producing T cell formation. Thus, we show that human blood CD1c cDC2s encompass two subsets that differ significantly in phenotype, that is, gene expression and functions. We propose that these two subsets of human cDC2s could potentially play contrasting roles in immunity or tolerance.

Metabotropic glutamate receptor 2/3 (mGluR2/3) agonists were shown previously to nonselectively decrease both cocaine- and food-maintained responding in rats. mGluR2 positive allosteric modulators (PAMs) may represent improved therapeutic compounds because of their modulatory properties and higher selectivity for mGluR2. We investigated the effects of the selective, brain penetrant and systemically active mGluR2 PAM potassium 3′-([2-cyclopentyl-6-7-dimethyl-1-oxo-2,3-dihydro-1H-inden-5yloxy]methyl)biphenyl l-4-carboxylate (BINA) and the mGluR2/3 agonist LY379268 on intravenous cocaine self-administration and cocaine-seeking behavior in rats that had short (1 h, ShA) or long (6 h, LgA) access to cocaine. The effects of BINA on food responding and food-seeking behavior were also investigated. Finally, we examined the effects of BINA on brain reward function and cocaine-induced reward enhancement using the intracranial self-stimulation procedure. BINA decreased cocaine self-administration in both ShA and LgA rats, with no effect on food self-administration. Alternatively, LY379268 nonselectively decreased both cocaine and food self-administration. BINA decreased cue-induced reinstatement of cocaine seeking with no effect on food seeking. The cocaine-induced enhancement of brain reward function was blocked by BINA, although the highest doses of BINA decreased brain reward function when administered alone, suggesting additive, rather than interactive, effects of BINA and cocaine. In conclusion, BINA attenuated the reinforcing and counteracted the reward-enhancing effects of cocaine and decreased cue-induced cocaine-seeking behavior, without affecting behaviors motivated by food reinforcement. The higher selectivity of BINA compared with an mGluR2/3 agonist for drug- vs. food-motivated behaviors suggests a therapeutic role for mGluR2 PAMs for the treatment of cocaine addiction and possibly other drugs of abuse.