Interaction of the chemokine CXCL12 with its receptor CXCR4 promotes neuronal function and survival during embryonic development and throughout adulthood. Previous studies indicated that μ-opioid agonists specifically elevate neuronal levels of the protein ferritin heavy chain (FHC), which negatively regulates CXCR4 signaling and affects the neuroprotective function of the CXCL12/CXCR4 axis. Here, we determined that CXCL12/CXCR4 activity increased dendritic spine density, and also examined FHC expression and CXCR4 status in opiate abusers and patients with HIV-associated neurocognitive disorders (HAND), which is typically exacerbated by illicit drug use. Drug abusers and HIV patients with HAND had increased levels of FHC, which correlated with reduced CXCR4 activation, within cortical neurons. We confirmed these findings in a nonhuman primate model of SIV infection with morphine administration. Transfection of a CXCR4-expressing human cell line with an iron-deficient FHC mutant confirmed that increased FHC expression deregulated CXCR4 signaling and that this function of FHC was independent of iron binding. Furthermore, examination of morphine-treated rodents and isolated neurons expressing FHC shRNA revealed that FHC contributed to morphine-induced dendritic spine loss. Together, these data implicate FHC-dependent deregulation of CXCL12/CXCR4 as a contributing factor to cognitive dysfunction in neuroAIDS.

The chemokine CXCL12 and its receptor, CXCR4, regulate neuronal migration, differentiation, and survival. Alterations of CXCL12/CXCR4 signaling are implicated in different neuropathologies, including the neurological complications of HIV infection. Opiates are important co-factors for progression to neuroAIDS and can disrupt the CXCL12/CXCR4 axis in vitro and in vivo. This paper will review recently identified mechanisms of opiate-induced CXCR4 impairment in neurons and introduce results from pilot studies in human brain tissue, which highlight the role of the protein ferritin heavy chain in HIV neuropathology in patients with history of drug abuse. KeywordsCXCR4; CXCL12; opiates; ferritin heavy chain; neuroAIDS; NR2B 1: IntroductionHuman immunodeficiency virus (HIV) continues to profoundly impact public health within the United States and around the world. With over 50,000 new cases of HIV-1 infection reported annually in the United States alone, the prevalence of individuals diagnosed with HIV/AIDS is increasing steadily according to the most recent reports from the Centers for Disease Control and Prevention (CDC, 2009). The social impact of HIV/AIDS disproportionally affects males and overwhelmingly affects minorities, underscoring disparities in risk factors and public health access across the socioeconomic spectrum (CDC, 2009). One such risk factor, illicit opiate abuse through intravenous drug use (IVDU), increases the risk of HIV exposure but also accelerates disease progression and exacerbates neurological involvement (Hu et al., 2005, Khurdayan et al., 2004, Hauser et al., 2006. Given the success of combined antiretroviral therapy (cART) and efforts to broaden treatment to include medically underserved areas, the average life expectancy of HIV Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. (Harrison et al., 2010), revealing the neurological impact of chronic HIV infection on an aging population (Valcour et al., 2004) and highlighting the importance of identifying the molecular mechanisms essential to the ability of opiates to promote neurological dysfunction. NIH Public Access 2: HIV neuropathology and Drug abuseThe natural history of HIV infection, coupled with the typically poor central nervous system (CNS) penetration of cART, predispose individuals for CNS complications over time.Following an acute, systemic viremia HIV seeds numerous tissues in the body, including the CNS, allowing it to harbor itself in an immunologically privileged environment and replicate chronically (Ghafouri et al., 2006). The resulting infection within the CNS can remain as...

Summary Quantifying protein and RNA expression within specific cell populations in vivo is an essential step in unraveling the complex mechanisms of neurological disease. The challenges associated with studying human brain tissue is commonly compounded by variations in post-mortem interval, formalin fixation time, and tissue processing among others. The result is a sample population that is inherently heterogeneous, requiring a single protocol that is sensitive to low levels of antigen while minimizing background and non-specific staining. Here, we describe a single immunohistochemistry (IHC) protocol on formalin fixed paraffin embedded human cortex which can be adapted to 1) quantify the relative protein expression of the chemokine receptor, CXCR4, using multispectral image (MSI) or 2) isolate neuronal RNA through automated laser capture microdissection (LCM).

This chapter recounts how “Ganas” went from a brief conversation and makeshift practice to an established structure in which students could ground their education. It is still hard to pin down, however, for its only permanent ethos is to serve its members, mostly consisting of Latino migrant workers and successive generations of Bennington undergraduates, which means instead that it is reinvented on a yearly basis, at the very least. Of late, it has come to include a course on court interpretation, prompted by immediate need and informed by interactions with the National Center for State Courts, a task force of experts led by the Vermont Office of the Court Administrator, and The Consortium on Forced Migration, Displacement and Education. Its continued relevance is sadly all too obvious, although I can but hope that one day its services will no longer be required.