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Glutamate is the major excitatory neurotransmitter of the nervous system. We previously found that glutamate activates normal human T-cells, inducing their adhesion and chemotaxis, via its glutamate receptors of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype 3 (GluR3) expressed in these cells. Here, we discovered that human T-leukemia (Jurkat) and cutaneous sezary T-lymphoma (HuT-78) cells also express high levels of GluR3. Furthermore, glutamate (10 nM) elevates CD147/EMMPRIN, a cancer-associated matrix metalloproteinases (MMPs) inducer, promoting spread of many tumors. Glutamate-induced CD147 elevation in both cancerous and normal human T-cells was mimicked by AMPA (glutamate/AMPA-receptor agonist) and blocked by CNQX (glutamate/AMPA-receptor antagonist). Importantly, glutamate also increased gelatinase MMP-9 secretion by T-lymphoma. Finally, ex vivo pre-treatment of T-leukemia with glutamate enhanced their subsequent in vivo engraftment into chick embryo liver and chorioallantoic membrane. Together, these findings reveal that glutamate elevates cancer associated proteins and activity in T-cell cancers and by doing so may facilitate their growth and spread, especially to and within the nervous system. If so, glutamate receptors in T-cell malignancies should be blocked. [ABSTRACT FROM AUTHOR]

A family of monomodified bovine serum albumin (BSA) linked to methotrexate (MTX) through a variety of spacers was prepared. All analogues were found to be prodrugs having low MTX-inhibitory potencies toward dihydrofolate reductase in a cell-free system. The optimal conjugates regenerated their antiproliferative efficacies following entrance into cancerous glioma cell lines and were significantly superior to MTX in an insensitive glioma cell line. A BSA–MTX conjugate linked through a simple ethylene chain spacer, containing a single peptide bond located 8.7 Å distal to the protein back bone, and apart from the covalently linked MTX by about 12 Å, was most effective. The inclusion of an additional disulfide bond in the spacer neither enhanced nor reduced the killing potency of this analogue. Disrupting the native structure of the carrier protein in the conjugates significantly reduced their antiproliferative activity. In conclusion, we have engineered BSA–MTX prodrug analogues which undergo intracellular reactivation and facilitate antiproliferative activities following their entrance into glioma cells. [ABSTRACT FROM AUTHOR]

Introduction: Molecular responses in the brains of persons with mild cognitive impairment (MCI), the earliest transitional state between normal aging and early Alzheimer's disease (AD), are poorly understood., Methods: We examined AD-related neuropathology and transcriptome changes in the neocortex of individuals with MCI relative to controls and temporal responses to the mild hypoxia in mouse brains., Results: Subsets of vascular early response to hypoxia genes were upregulated in MCI prior to the buildup of AD neuropathology. Early activation of pro-angiogenic hypoxia-inducible factor signaling in response to mild hypoxia was detected in mouse brains similar to those that were altered in MCI. Protracted responses to hypoxia were characterized by activation of phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt)-the mammalian target of rapamycin (mTOR) pathways in brain microvessel isolates., Discussion: These findings suggest that cerebrovascular remodeling is an important antecedent to the development of dementia and a component of the homeostatic response to reduced oxygen tension in aging prior to the onset of AD., (© 2021 the Alzheimer's Association.)

Competing Interests: None

Accumulation and aggregation of the intrinsically disordered protein α-synuclein (α-Syn) into amyloid fibrils are hallmarks of a series of heterogeneous neurodegenerative disorders, known as synucleinopathies and most notably Parkinson's disease (PD). The crucial role of α-Syn aggregation in PD makes it an attractive target for the development of disease-modifying therapeutics that would inhibit α-Syn aggregation or disrupt its preformed fibrillar assemblies. To this end, we have designed and synthesized two naphthoquinone-dopamine-based hybrid small molecules, NQDA and Cl-NQDA, and demonstrated their ability to inhibit in vitro amyloid formation by α-Syn using ThT assay, CD, TEM, and Congo red birefringence. Moreover, these hybrid molecules efficiently disassembled preformed fibrils of α-Syn into nontoxic species, as evident from LUV leakage assay. NQDA and Cl-NQDA were found to have low cytotoxicity and they attenuated the toxicity induced by α-Syn towards SH-SY5Y neuroblastoma cells. NQDA was found to efficiently cross an in vitro human blood-brain barrier model. These naphthoquinone-dopamine based derivatives can be an attractive scaffold for therapeutic design towards PD., (© 2020 Wiley-VCH GmbH.)

Claudins are transmembrane proteins that form the backbone of the tight junctions (TJs) at the blood-brain barrier (BBB). TJs are cellular structures that physically obstruct the inter-endothelial space and restrict the paracellular diffusion of blood-borne substances from the peripheral circulation into the CNS. TJs are also dynamic structures that rapidly respond to external signals that produce changes in BBB permeability. We focus here on the biochemical and immunohistochemical properties of claudin-5 as expressed in three in vitro models of the BBB, and show that the contact co-culture of endothelial cells with glial cells significantly increases claudin-5 expression.

Numerous in-vitro models of the blood-brain barrier (BBB) have been developed in the hope to mimic as closely as possible the in-vivo BBB characteristics. Most models however display BBB tightness properties still very remote from those found in-vivo. We describe here the properties of an in-vitro BBB model in three configurations: primary porcine brain endothelial cells (PBEC) grown in a monoculture, or as a co-culture in close proximity to rat glial cells (contact), or with the latter at distance (non-contact). The BBB tightness as reflected by measurements of the permeability (Pe) to sucrose and of the transendothelial electrical resistance (TEER) showed that only the contact co-culture closely mimic the in-vivo BBB (Pe=0.1910(-6)+/-0.01 cm/s and TEER up to 1650 Omegacm2). While no changes in the expression pattern of three of the major tight junction proteins, claudin-5, occludin and ZO-1, were observed using immunohistochemistry, western blot analysis showed that the expression levels of claudin-5 and occludin increase when PBEC are cultured in contact with glial cells. In addition, we found, in the contact co-culture model, a reduced sensitivity of the TEER to vinblastine, a P-glycoprotein (Pgp) substrate that disrupts the cell cytoskeleton, indicating an improved functionality of the Pgp transporters in this configuration. We conclude that the close proximity of astrocytes is crucial to the development of a tight BBB.