%0 Journal Article
%T RNase 7 Contributes to the Cutaneous Defense against Enterococcus faecium
%A Bente K£¿ten
%A Maren Simanski
%A Regine Gl£¿ser
%A Rainer Podschun
%A Jens-Michael Schr£¿der
%A J¨¹rgen Harder
%J PLOS ONE
%D 2009
%I Public Library of Science (PLoS)
%R 10.1371/journal.pone.0006424
%X Background Human skin is able to mount a fast response against invading microorganisms by the release of antimicrobial proteins such as the ribonuclease RNase 7. Because RNase 7 exhibits high activity against Enterococcus faecium the aim of this study was to further explore the role of RNase 7 in the cutaneous innate defense system against E. faecium. Methodology/Principal Findings Absolute quantification using real-time PCR and ELISA revealed that primary keratinocytes expressed high levels of RNase 7. Immunohistochemistry showed RNase 7 expression in all epidermal layers of the skin with an intensification in the upper more differentiated layers. Furthermore, RNase 7 was secreted by keratinocytes in vitro and in vivo in a site-dependent way. RNase 7 was still active against E. faecium at low pH (5.5) or high NaCl (150 mM) concentration and the bactericidal activity of RNase 7 against E. faecium required no ribonuclease activity as shown by recombinant RNase 7 lacking enzymatic activity. To further explore the role of RNase 7 in cutaneous defense against E. faecium, we investigated whether RNase 7 contributes to the E. faecium killing activity of skin extracts derived from stratum corneum. Treatment of the skin extract with an RNase 7 specific antibody, which neutralizes the antimicrobial activity of RNase 7, diminished its E. faecium killing activity. Conclusions/Significance Our data indicate that RNase 7 contributes to the E. faecium-killing activity of skin extracts and suggest an important role for RNase 7 in the protection of human skin against E. faecium colonization.
%U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006424