title: SHP-1 plays a crucial role in CD40 signaling reciprocity.
abstract: CD40 plays dual immunoregulatory roles in Leishmania major infection and tumor regression. The functional duality emerges from CD40-induced reciprocal p38MAPK and ERK-1/2 phosphorylations. Because phosphotyrosine-based signaling in hematopoietic cells is regulated by the phosphotyrosine phosphatase SHP-1, which is not implied in CD40 signaling, we examined whether SHP-1 played any roles in CD40-induced reciprocal signaling and anti-leishmanial function. We observed that a weaker CD40 stimulation increased SHP-1 activation. ERK-1/2 inhibition or p38MAPK overexpression inhibited CD40-induced SHP-1 activation. An ultra-low-dose, CD40-induced p38MAPK phosphorylation was enhanced by SHP-1 inhibition but reduced by SHP-1 overexpression. A reverse profile was observed with ERK-1/2 phosphorylation. SHP-1 inhibition reduced syk phosphorylation but increased lyn phosphorylation; syk inhibition reduced but lyn inhibition enhanced CD40-induced SHP-1 phosphorylation. Corroborating these findings, in L. major-infected macrophages, CD40-induced SHP-1 phosphorylation increased and SHP-1 inhibition enhanced CD40-induced p38MAPK activation and inducible NO synthase expression. IL-10 enhanced SHP-1 phosphorylation and CD40-induced ERK-1/2 phosphorylation but reduced the CD40-induced p38MAPK phosphorylation, whereas anti-IL-10 Ab exhibited reverse effects on these CD40-induced functions, identifying IL-10 as a crucial element in the SHP-1-MAPK feedback system. Lentivirally overexpressed SHP-1 rendered resistant C57BL/6 mice susceptible to the infection. Lentivirally expressed SHP-1 short hairpin RNA enhanced the CD40-induced L. major parasite killing in susceptible BALB/c mice. Thus, we establish an SHP-1-centered feedback system wherein SHP-1 modulates CD40-induced p38MAPK activation threshold and reciprocal ERK-1/2 activation, establishing itself as a critical regulator of CD40 signaling reciprocity and mechanistically re-emphasizing its role as a potential target against the diseases where CD40 is involved.
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Tabish Hasan
authors.initials: TH
authors.lastname: Khan
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Neetu
authors.initials: N
authors.lastname: Srivastava
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Ankita
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Archana
authors.initials: A
authors.lastname: Sareen
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Ram K
authors.initials: RK
authors.lastname: Mathur
authors.affiliation: Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai 410 210, India; and.
authors.forename: Ajit G
authors.initials: AG
authors.lastname: Chande
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India;
authors.forename: Krishnasastry V
authors.initials: KV
authors.lastname: Musti
authors.affiliation: Vidyasagar University, Midnapore 721 102, India.
authors.forename: Somenath
authors.initials: S
authors.lastname: Roy
authors.affiliation: Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai 410 210, India; and.
authors.forename: Robin
authors.initials: R
authors.lastname: Mukhopadhyaya
authors.affiliation: National Centre for Cell Science, Ganeshkhind, Pune 411 007, India; sahab@nccs.res.in.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Saha
mesh_terms: D000818:Animals; D019013:CD40 Antigens / Q000276:immunology*; D004789:Enzyme Activation / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000276:immunology; D018320:Leishmania major / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D048052:Mitogen-Activated Protein Kinase 3 / Q000276:immunology; D052247:Nitric Oxide Synthase Type II; D010766:Phosphorylation / Q000276:immunology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000276:immunology*; D011505:Protein-Tyrosine Kinases / Q000276:immunology; D000072377:Syk Kinase; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology
chemical_list: D019013:CD40 Antigens; C556062:IL10 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D016753:Interleukin-10; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509248:Ptpn6 protein, mouse