Adult hippocampal neurogenesis is to a large degree controlled at the level of cell survival, and a number of potential mediators of this effect have been postulated. Here, we investigated the small heat shock protein Hspb8, which, because of its pleiotropic prosurvival effects in other systems, was considered a particularly promising candidate factor. Hspb8 is, for example, found in plaques of Alzheimer disease but exerts neuroprotective effects. We found that expression of Hspb8 increased during differentiation in vitro and was particularly associated with later stages (48–96 h) of differentiation. Gain-of-function and loss-of-function experiments supported the hypothesis that Hspb8 regulates cell survival of new neurons in vitro . In the dentate gyrus of adult mice in vivo , lentiviral overexpression of Hspb8 doubled the surviving cells and concomitantly promoted differentiation and net neurogenesis without affecting precursor cell proliferation. We also discovered that the truncated form of the crystal...

Expression of appropriate neurotransmitters (NTs) is essential for development and function of neural circuits (Misgeld et al., 2002; Root et al., 2008). However, the NT expressed by a neuron is not immutable and fixed, but capable of change in response...

Human immunodeficiency virus 1 (HIV-1) infection may result in activation of peripheral monocytes followed by their infiltration into the CNS, where the release of proinflammatory mediators causes neurologic disease. Previously, we detected high levels of soluble CD40 ligand (CD40L) in CSF and plasma of HIV-infected patients with cognitive impairment. We now show that CD40, a receptor for CD40L, is highly expressed in brain endothelial cells of patients affected by HIV-1 encephalitis (HIVE), suggesting an important role for the CD40/CD40L dyad in regulating blood–brain barrier (BBB) functions. This concept was further supported by in vitro experiments. Exposure of primary human brain microvascular endothelial cells (BMVECs) to CD40L upregulated the expression of adhesion molecules intracellular adhesion molecule-1 and vascular cell adhesion molecule-1, which caused a fourfold increase in monocyte adhesion to BMVECs and stimulated migration across an in vitro BBB model. Investigations into the intracellular...

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) is a significant source of disability in the HIV-infected population. Even with stringent adherence to anti-retroviral therapy, >50% of patients living with HIV-1 will develop HAND ([Heaton et al., 2010][1]). Because suppression of viral replication alone is not enough to stop HAND progression, there is a need for an adjunctive neuroprotective therapy in this population. To this end, we have developed a small-molecule brain-penetrant inhibitor with activity against mixed-lineage kinase 3 (MLK3), named URMC-099. MLK3 activation is associated with many of the pathologic hallmarks of HAND ([Bodner et al., 2002][2], [2004][3]; [Sui et al., 2006][4]) and therefore represents a prime target for adjunctive therapy based on small-molecule kinase inhibition. Here we demonstrate the anti-inflammatory and neuroprotective effects of URMC-099 in multiple murine and rodent models of HAND. In vitro , URMC-099 treatment reduced inflammatory cyto...

Kinesin-6 Knockdown Affects Axons and Dendrites Shen Lin, Mei Liu, Olga I. Mozgova, Wenqian Yu, and Peter W. Baas (see pages [14033–14049][1]) Microtubules are essential for axonal and dendritic growth and for the establishment of neuronal polarity. Short tubulin polymers formed in the soma

Although pudendal nerve (PN) injury in the rat is an accepted animal model for studying stress urinary incontinence (SUI), the effect of acute PN injury on EUS function has not been examined in detail. In this study we evaluated the changes in urinary bladder function, EUS activity and leak point pressure (LPP) after acute PN transection in female Sprague-Dawley rats. Control cystometrograms (CMGs) and EUS electromyograms (EUS-EMGs) were conducted on rats (300-380 g, n=14) under urethane anesthesia and then unilateral pudendal nerve transection (UPNT) or bilateral pudendal nerve transection (BPNT) was performed. CMGs, EUS-EMGs and (LPP) tests were performed before and after the nerve transections. All animals exhibited micturition reflexes during control CMGs; however after UPNT and BPNT, voiding abnormalities were detected including a 25%-33% increase in volume threshold for initiating voiding, a three fold increase in residual volume and 20%-80% decreases in contraction amplitude, contraction duration, v...

RNA interference (RNAi), which allows selective gene silencing, has been proposed for functional genomic analysis and for the treatment of human disease. However, induction of RNAi in mammalian cells by expression of double-stranded RNA can activate innate antiviral response pathways that perturb off-target gene expression. The activation and functional consequences of these effects in neurons are unknown. We find that expression of subsets of short hairpin RNAs (shRNAs) in rat hippocampal pyramidal neurons can have off-target effects that reduce the complexity of dendritic arbors and trigger the loss of dendritic spines. Morphological changes are accompanied by electrophysiological perturbations in passive membrane properties and a decrease in the number and strength of excitatory and inhibitory synapses. These perturbations depend on the shRNA sequence and are independent of the identity of the targeted protein. Our results indicate that off-target effects of RNAi severely perturb neuronal structure and ...

HIV-1 infection of the nervous system causes various neurological diseases, and synaptic degeneration is likely a critical step in the neuropathogenesis. Our prior studies revealed a significant decrease of synaptic protein, specifically in the spinal dorsal horn of patients with HIV-1 in whom pain developed, suggesting a potential contribution of synaptic degeneration to the pathogenesis of HIV-associated pain. However, the mechanism by which HIV-1 causes the spinal synaptic degeneration is unclear. Here, we identified a critical role of microglia in the synaptic degeneration. In primary cortical cultures (day in vitro 14) and spinal cords of 3- to 5-month-old mice (both sexes), microglial ablation inhibited gp120-induced synapse decrease. Fractalkine (FKN), a microglia activation chemokine specifically expressed in neurons, was upregulated by gp120, and knockout of the FKN receptor CX3CR1, which is predominantly expressed in microglia, protected synapses from gp120-induced toxicity. These results indicat...

Efficient excitatory transmission depends on a family of transporters that use the Na+-electrochemical gradient to maintain low synaptic concentrations of glutamate. These transporters consume substantial energy in the spatially restricted space of fine astrocytic processes. GLT-1 (EAAT2) mediates the bulk of this activity in forebrain. To date, relatively few proteins have been identified that associate with GLT-1. In the present study, GLT-1 immunoaffinity isolates were prepared from rat cortex using three strategies and analyzed by liquid chromatography-coupled tandem mass spectrometry. In addition to known interacting proteins, the analysis identified glycolytic enzymes and outer mitochondrial proteins. Using double-label immunofluorescence, GLT-1 was shown to colocalize with the mitochondrial matrix protein, ubiquinol-cytochrome c reductase core protein 2 or the inner mitochondrial membrane protein, ADP/ATP translocase, in rat cortex. In biolistically transduced hippocampal slices, fluorescently tagge...

Chronic pain is increasingly recognized as an important comorbidity of HIV-infected patients, however, the exact molecular mechanisms of HIV-related pain are still elusive. CCAAT/enhancer binding proteins (C/EBPs) are expressed in various tissues, including the CNS. C/EBPβ, one of the C/EBPs, is involved in the progression of HIV/AIDS, but the exact role of C/EBPβ and its upstream factors are not clear in HIV pain state. Here, we used a neuropathic pain model of perineural HIV envelope glycoprotein gp120 application onto the rat sciatic nerve to test the role of phosphorylated C/EBPβ (pC/EBPβ) and its upstream pathway in the spinal cord dorsal horn (SCDH). HIV gp120 induced overexpression of pC/EBPβ in the ipsilateral SCDH compared with contralateral SCDH. Inhibition of C/EBPβ using siRNA against C/EBPβ reduced mechanical allodynia. HIV gp120 also increased TNFα, TNFRI, mitochondrial superoxide (mtO2·−), and pCREB in the ipsilateral SCDH. ChIP-qPCR assay showed that pCREB enrichment on the C/EBPβ gene prom...