Doxycycline inhibits experimental cerebral malaria by reducing inflammatory immune reactions and tissue-degrading mediators

PLoS One. 2018 Feb 13;13(2):e0192717. doi: 10.1371/journal.pone.0192717. eCollection 2018.

Abstract

Malaria ranks among the most important infectious diseases worldwide and affects mostly people living in tropical countries. Mechanisms involved in disease progression are still not fully understood and specific treatments that might interfere with cerebral malaria (CM) are limited. Here we show that administration of doxycycline (DOX) prevented experimental CM (ECM) in Plasmodium berghei ANKA (PbA)-infected C57BL/6 wildtype (WT) mice in an IL-10-independent manner. DOX-treated mice showed an intact blood-brain barrier (BBB) and attenuated brain inflammation. Importantly, if WT mice were infected with a 20-fold increased parasite load, they could be still protected from ECM if they received DOX from day 4-6 post infection, despite similar parasitemia compared to control-infected mice that did not receive DOX and developed ECM. Infiltration of T cells and cytotoxic responses were reduced in brains of DOX-treated mice. Analysis of brain tissue by RNA-array revealed reduced expression of chemokines and tumour necrosis factor (TNF) in brains of DOX-treated mice. Furthermore, DOX-administration resulted in brains of the mice in reduced expression of matrix metalloproteinase 2 (MMP2) and granzyme B, which are both factors associated with ECM pathology. Systemic interferon gamma production was reduced and activated peripheral T cells accumulated in the spleen in DOX-treated mice. Our results suggest that DOX targeted inflammatory processes in the central nervous system (CNS) and prevented ECM by impaired brain access of effector T cells in addition to its anti-parasitic effect, thereby expanding the understanding of molecular events that underlie DOX-mediated therapeutic interventions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimalarials / pharmacology*
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / immunology
  • Chemokines / metabolism
  • Disease Models, Animal
  • Doxycycline / pharmacology*
  • Female
  • Inflammation / immunology
  • Inflammation / prevention & control
  • Inflammation Mediators / metabolism
  • Interleukin-10 / metabolism
  • Lymphocyte Activation / drug effects
  • Malaria, Cerebral / immunology
  • Malaria, Cerebral / parasitology
  • Malaria, Cerebral / prevention & control*
  • Matrix Metalloproteinase 2 / metabolism
  • Matrix Metalloproteinase 9 / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Parasitemia / immunology
  • Parasitemia / prevention & control
  • Plasmodium berghei / immunology
  • Plasmodium berghei / pathogenicity
  • Spleen / drug effects
  • Spleen / immunology
  • T-Lymphocyte Subsets / drug effects
  • T-Lymphocyte Subsets / immunology

Substances

  • Antimalarials
  • Chemokines
  • IL10 protein, mouse
  • Inflammation Mediators
  • Interleukin-10
  • Matrix Metalloproteinase 2
  • Mmp2 protein, mouse
  • Matrix Metalloproteinase 9
  • Mmp9 protein, mouse
  • Doxycycline

Grants and funding

This work was financially supported by intramural funding (BONFOR program) of the Medical Faculty of the Friedrich-Wilhelms University Bonn to SS, BS and JK (www.ukb.unibonn.de/bonfor/) and also by the German Centre for Infection Research (Deutsches Zentrum fuer Infektionsforschung, DZIF, www.dzif.de). Part of this work was supported by an intramural grant from Singapore’s Agency for Science, Technology and Research (A*STAR). BS and AH are members of the Bonn Excellence Cluster “Immunosensation” EXC1023.