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AIDS Weekly Plus
Findings from Northwestern University Broaden Understanding of HIV/AIDS
Staff Writer
May 13, 2013


2013 MAY 13 (NewsRx) -- By a News Reporter-Staff News Editor at AIDS Weekly -- Research findings on Immune System Diseases and Conditions are discussed in a new report. According to news reporting originating in Chicago, Illinois, by NewsRx journalists, research stated, "Activation of the CXC chemokine receptor 4 (CXCR4) in Cajal-Retzius cells by CXC chemokine ligand 12 (CXCL12) is important for controlling their excitability. CXCR4 is also a co-receptor for the glycoprotein 120 (gp120) of the envelope of the human immunodeficiency virus type 1 (HIV-1), and binding of gp120 to CXCR4 may produce pathological effects."

The news reporters obtained a quote from the research from Northwestern University, "In order to study CXCR4-dependent modulation of membrane excitability, we recorded in cell-attached configuration spontaneous action currents from hippocampal stratum lacunosum-moleculare Cajal-Retzius cells of the CXCR4-EGFP mouse. CXCL12 (50 nM) powerfully inhibited firing independently of synaptic transmission, suggesting that CXCR4 regulates an intrinsic conductance. This effect was prevented by conditioning slices with BAPTA-AM (200 M), and by blockers of the BK calcium-dependent potassium channels (TEA (1 mM), paxilline (10 M) and iberiotoxin (100 nM)). In contrast, exposure to gp120 (pico-to nanomolar range, alone or in combination with soluble cluster of differentiation 4 (CD4)), enhanced spontaneous firing frequency. This effect was prevented by the CXCR4 antagonist AMD3100 (1 M) and was absent in EGFP-negative stratum lacunosum-moleculare interneurons. Increased excitability was prevented by treating slices with BAPTA-AM or bumetanide, suggesting that gp120 activates a mechanism that is both calcium-and chloride-dependent."

According to the news reporters, the research concluded: "Our results demonstrate that CXCL12 and gp120 modulate the excitability of Cajal-Retzius cells in opposite directions. We propose that CXCL12 and gp120 either generate calcium responses of different strength or activate distinct pools of intracellular calcium, leading to agonist-specific responses, mediated by BK channels in the case of CXCL12, and by a chloride-dependent mechanism in the case of gp120."

For more information on this research see: The chemokine CXCL12 and the HIV-1 envelope protein gp120 regulate spontaneous activity of Cajal-Retzius cells in opposite directions. Journal of Physiology, 2012;590(Pt 13):3185-202. (Wiley-Blackwell - www.wiley.com/; Journal of Physiology - onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-7793)

Our news correspondents report that additional information may be obtained by contacting I. Marchionni, Northwestern University, Dept. of Physiology, Feinberg School of Medicine, 303 E Chicago Ave, Tarry Blg Rm 5-707, Chicago, IL 60611, United States (see also Immune System Diseases and Conditions).

Keywords for this news article include: Chicago, Illinois, HIV/AIDS, Peptides, Immunology, RNA Viruses, Retroviridae, United States, CXC Chemokines, HIV Infections, Chemokine CXCL12, Membrane Proteins, Biological Factors, Cytokine Receptors, Vertebrate Viruses, Chemokine Receptors, Chemotactic Factors, Primate Lentiviruses, Inflammation Mediators.

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