Blakely, Randy

The majority of research on drug addiction centers on dopamine (DA)- driven synaptic plasticities and how these changes ultimately lead to compulsive drug seeking. However, growing evidence supports a role of glial factors in various steps that lead to drug abuse and addiction. In this regard, significant evidence implicates glial glutamate (Glu) transporters (GLT-1) and cystine/Glu exchangers (xCT) in determining synaptic and extrasynaptic levels of Glu that support the acute and chronic actions of drugs of abuse. -lactam antibiotics have been found in rodent models to upregulate CNS GLT-1 and xCT and thereby contribute to reinstatement after chronic drug exposure and withdrawal.
Previously, the Blakely lab identified a glial expressing gene, swip-10, in Caenorhabditis elegans, whose deletion results in the hyperdominergic phenotype Swimming-Induced Paralysis (Swip), supported by Glu signalingdependent DA neuron hyperexcitability that ultimately drives oxidative stress and DA neuron degeneration. Both SWIP-10 and its putative mammalian ortholog MBLAC1 possess a highly conserved metallo -lactamase domain, and MBLAC1 has been found to bind the Glu modulating, b-lactam antibiotic ceftriaxone (Cef). Indeed, immunodepletion studies indicate that MBLAC1 may be the major highaffinity Cef-binding protein in the brain, leading to the hypothesis that MBLAC1 has a Glu modulatory role(s). Recently a functional role of MBLAC1 been proposed, involving activity as a 3’ exonuclease that processes polyA- mRNAs, including RNAs encoding cell replication-dependent histones. How this role, or others, may support the actions of MBLAC1 in the brain and the non-microbial actions of Cef to extracellular Glu homeostasis, is unclear. Recently, the Blakely lab generated Mblac1-/- mice as a tool to investigate these issues. The following work investigated the requirements of MBLAC1 in growth and the actions of Cef in mouse embryonic fibroblasts (MEFs) cultured from either Mblac1+/+ and Mblac1-/- mice. The presented data suggested that Mblac1-/- MEFs display attenuated growth and cell proliferation relative to Mblac1+/+ MEFs. For the first time, the in vitro protective actions of Cef against oxidative stress is shown to be dependent on MBLAC1. The following studies presented contribute to a definition of the role of MBLAC1 and as a Cef binding protein in native preparations, with findings that can drive models for the role of MBLAC1 in the CNS.

The blood brain barrier (BBB) is the brain’s defense mechanism in its maintenance of homeostasis. This network comprises an intricate, functional shield for the human brain, equipped with highly specialized cells like pericytes, astrocytic end-feet, endothelial and neuronal cells. This highly organized barrier maintains the brain’s structural integrity by revealing a discriminatory absorbency of molecules based on their molecular weight and ample fat solubility. In view of this impediment to the delivery of many prospective therapeutic agents from crossing the inviolate BBB, a myriad of innovative surgical and pharmacological interventions have been developed to bypass it, one of which is the BBBD protocol.