SHP-1 plays a crucial role in CD40 signaling reciprocity

• Published in: The Journal of immunology (1950) 2014-10, Vol.193 (7), p.3644-3653
• Main Authors: Khan, Tabish Hasan, Srivastava, Neetu, Srivastava, Ankita, Sareen, Archana, Mathur, Ram K, Chande, Ajit G, Musti, Krishnasastry V, Roy, Somenath, Mukhopadhyaya, Robin, Saha, Bhaskar
• Format: Article
• Language: English
• Subjects: Animals; CD40 Antigens - immunology; Enzyme Activation - immunology; Interleukin-10 - immunology; Intracellular Signaling Peptides and Proteins - immunology; Leishmania major; Leishmania major - immunology; Leishmaniasis, Cutaneous - immunology; Leishmaniasis, Cutaneous - pathology; Macrophages - immunology; Macrophages - pathology; MAP Kinase Signaling System - immunology; Mice; Mice, Inbred BALB C; Mitogen-Activated Protein Kinase 3 - immunology; Nitric Oxide Synthase Type II; p38 Mitogen-Activated Protein Kinases - immunology; Phosphorylation - immunology; Protein Tyrosine Phosphatase, Non-Receptor Type 6 - immunology; Protein-Tyrosine Kinases - immunology; Syk Kinase
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1400620

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.