The immunosuppressant Protosappanin A diminished recipient T cell migration into allograft via inhibition of IP-10 in rat heart transplant

PLoS One. 2014 May 5;9(5):e96138. doi: 10.1371/journal.pone.0096138. eCollection 2014.

Abstract

The immunosuppressant Protosappanin A (PrA), isolated from the medicinal herb, promotes cardiac allograft survival, diminishes inflammatory cell infiltration, and inhibits interferon γ-induced protein 10 kDa (IP-10) mRNA expression in rats cardiac grafts. Binding of the chemokine IP-10 to its cognate receptor, CXCR3, plays crucial roles in allograft immunity, especially by mediating the recruitment of effector T cells to allografted tissues. In this study, we attempted to determine whether PrA-mediated inhibition of IP-10 contributes to the effect of reduced T cell infiltration into cardiac allograft within a rat model. Administration of PrA (25 mg/kg daily) via oral gavage following heart transplantation significantly reduced the increase of IP-10 mRNA level in allograft and prevented IP-10 secretion by peripheral blood mononuclear cells (PBMC) isolated from recipient rats seven days posttransplantation. Furthermore, in vitro experiments demonstrated that PrA addition to control PBMC prevented IP-10 secretion. Chemotactic migration assays were utilized to evaluate recipient T cell migration towards PBMC supernatant. PrA administration impaired PBMC supernatant-induced T cell migration. Additional in vitro experiments revealed that PrA slightly reduced naïve T cell migration towards chemokines. The presence of IP-10 in PBMC supernatant prevented PrA from reducing T cell migration in PrA-treated recipients. Neither CXCR3 chemokine ligand Mig nor non-CXCR3 chemokine ligand SDF-1 had any effect on T cell migration in PrA-treated recipients. The addition of anti-CXCR3 antibody restored PrA-mediated inhibition of T cell migration. Immunofluorescence microscopy showed that IP-10 was expressed mainly in CD68 positive infiltrating monocytes. Furthermore, PrA consistently reduced CXCR3+T cell infiltration into cardiac allografts. The reduced intensity of CXCR3 staining in PrA-treated allografts contributed to the previously depressed naïve T cell migrating activity induced by PrA. Collectively, these data indicate that PrA inhibition of IP-10 activity reduced recipient T cell migration and infiltration of cardiac allografts, thus partially explaining the immunosuppressive effect of PrA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allografts
  • Animals
  • Antigens, CD / immunology
  • Antigens, Differentiation, Myelomonocytic / immunology
  • Cell Movement / drug effects*
  • Cell Movement / immunology
  • Chemokine CXCL10 / immunology*
  • Heart Transplantation*
  • Immunosuppressive Agents / pharmacology*
  • Phenols / pharmacology*
  • Rats
  • Rats, Inbred Lew
  • Receptors, CXCR3 / immunology
  • T-Lymphocytes / immunology*

Substances

  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD68 protein, rat
  • Chemokine CXCL10
  • Cxcl10 protein, rat
  • Cxcr3 protein, rat
  • Immunosuppressive Agents
  • Phenols
  • Receptors, CXCR3
  • protosappanin A

Grants and funding

Project was supported by The Foundation of Heilongjiang Educational Committee (12531286), National Nature Science Foundation of China (81200180), New Teachers' Fund for Doctor Stations, Ministry of Education (20122307120021), Science and technology talent Foundation of Harbin (RC2008QN003003), the Heilongjiang Province Nature Foundation of Great Subject (ZJY03-7), Foundation for New Century Excellent Talents in Heilongjiang Province (1154-NCET-009), Post-doctoral Foundation of China (2011M501065), and Key Laboratory of Myocardial Ischemia Mechanism and Treatment (Harbin Medical University), Ministry of Education (KF201211). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.