bafilomycin-a1 and Herpes-Simplex

Viral double-stranded RNA (dsRNA) and its synthetic analog poly (I:C) are recognized via multiple pathways and induce the expression of genes related to inflammation. In the present study, we demonstrate that poly (I:C) specifically induced the expression of matrix metallo-proteinase-9 (MMP-9) in HaCaT keratinocytes. Studies using specific pharmacological inhibitors revealed the involvement of NF-κB, p38 MAPK, and PI-3K signal transduction pathways in poly (I:C)-induced MMP-9 gene expression. MMP-9 gene induction was sensitive toward treatment with the macrolide antibiotic bafilomycin A1, a vacuolar H(+)-ATPase inhibitor, and with the lysosomotropic agent chloroquine. However, cycloheximide treatment only partially blocked poly (I:C)-induced MMP-9 gene expression. Although HaCaT keratinocytes produce a number of cytokines and chemokines in response to poly (I:C), stimulation experiments revealed that exclusively TNFα strongly promoted MMP-9 gene expression. During the antiviral response MMP-9 expression may be of importance for the tissue injury phase.

Topics: Cell Line, Transformed; Herpes Simplex; Herpesvirus 1, Human; Humans; Keratinocytes; Macrolides; Matrix Metalloproteinase 9; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Poly I-C; RNA, Double-Stranded; Signal Transduction; Skin; Tumor Necrosis Factor-alpha; Up-Regulation; Vacuolar Proton-Translocating ATPases

The neurotropic virus, herpes simplex type 1 (HSV-1), inhibits the excitability of peripheral mammalian neurons, but the molecular mechanism of this effect has not been identified. Here, we use voltage-clamp measurement of ionic currents and an antibody against sodium channels to show that loss of excitability results from the selective, precipitous, and complete internalization of voltage-activated sodium channel proteins from the plasma membrane of neurons dissociated from rat dorsal root ganglion. The internalization process requires viral protein synthesis but not viral encapsulation, and does not alter the density of voltage-activated calcium or potassium channels. However, internalization is blocked completely when viruses lack the neurovirulence factor, infected cell protein 34.5, or when endocytosis is inhibited with bafilomycin A(1) or chloroquine. Although it has been recognized for many years that viruses cause cell pathology by interfering with signal transduction pathways, this is the first example of viral pathology resulting from selective internalization of an integral membrane protein. In studying the HSV-induced redistribution of sodium channels, we have uncovered a previously unknown pathway for the rapid and dynamic control of excitability in sensory neurons by internalization of sodium channels.

Topics: Action Potentials; Animals; Anti-Bacterial Agents; Antimalarials; Chloroquine; Endocytosis; Enzyme Inhibitors; Female; Ganglia, Spinal; Herpes Simplex; Herpesvirus 1, Human; Humans; Immunoenzyme Techniques; Macrolides; Male; Neurons; Proton-Translocating ATPases; Rats; Rats, Sprague-Dawley; Sodium Channels; Viral Proteins; Virus Activation