title: MAPK-directed phosphatases preferentially regulate pro- and anti-inflammatory cytokines in experimental visceral leishmaniasis: involvement of distinct protein kinase C isoforms.
abstract: The role of phosphatases in the impairment of MAPK signaling, which is directly responsible for Leishmania-induced macrophage dysfunction, is still poorly understood. Gene expression profiling revealed that Leishmania donovani infection markedly up-regulated the expression of three phosphatases: MKP1, MKP3, and PP2A. Inhibition of these phosphatases prior to infection points toward preferential induction of the Th2 response through deactivation of p38 by MKP1. On the other hand, MKP3 and PP2A might play significant roles in the inhibition of iNOS expression through deactivation of ERK1/2. Among various PKC isoforms, PKCzeta was associated with induction of MKP3 and PP2A in infected macrophages, whereas PKCepsilon was correlated with MKP1 induction. Inhibition of phosphatases in L. donovani-infected BALB/c mice shifted the cytokine balance in favor of the host by inducing TNF-alpha and iNOS expression. This was validated by cystatin, an immunomodulator and curing agent for experimental visceral leishmaniasis, which showed that inhibition of MKPs and PP2A activity may be necessary for a favorable T cell response and suppression of organ parasite burden. This study, for the first time, suggests the possibility of the involvement of MAPK-directed phosphatases in the establishment of L. donovani infection.
authors.affiliation: Infectious Diseases and Immunology Division, Indian Institute of Chemical Biology, Kolkata, India.
authors.forename: Susanta
authors.initials: S
authors.lastname: Kar
authors.forename: Anindita
authors.initials: A
authors.lastname: Ukil
authors.forename: Gunjan
authors.initials: G
authors.lastname: Sharma
authors.forename: Pijush K
authors.initials: PK
authors.lastname: Das
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015891:Cystatins / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis*; D054638:Dual Specificity Phosphatase 1 / Q000502:physiology*; D054642:Dual Specificity Phosphatase 6 / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D007527:Isoenzymes / Q000502:physiology*; D007898:Leishmaniasis, Visceral / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D052247:Nitric Oxide Synthase Type II / Q000235:genetics; D011493:Protein Kinase C / Q000502:physiology*; D054648:Protein Phosphatase 2 / Q000502:physiology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D015891:Cystatins; D016207:Cytokines; D007527:Isoenzymes; D052247:Nitric Oxide Synthase Type II; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D054648:Protein Phosphatase 2; D054638:Dual Specificity Phosphatase 1; D054642:Dual Specificity Phosphatase 6; C517020:Dusp1 protein, mouse; C517036:Dusp6 protein, mouse