Heterologous Expression of the Pathogen-Specific LIC11711 Gene in the Saprophyte <i>L. biflexa</i> Increases Bacterial Binding to Laminin and Plasminogen

• Main Authors: Leandro Toshio Kochi, Luis Guilherme Virgílio Fernandes, Ana Lucia Tabet Oller Nascimento
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Pathogens
• Subjects: <i>Leptospira</i>; leptospirosis; virulence
• Online Access: https://www.mdpi.com/2076-0817/9/8/599

Leptospirosis is a febrile disease and the etiological agents are pathogenic bacteria of the genus <i>Leptospira</i>. The leptospiral virulence mechanisms are not fully understood and the application of genetic tools is still limited, despite advances in molecular biology techniques. The leptospiral recombinant protein LIC11711 has shown interaction with several host components, indicating a potential function in virulence. This study describes a system for heterologous expression of the <i>L. interrogans</i> gene <i>lic11711</i> using the saprophyte <i>L. biflexa</i> serovar Patoc as a surrogate, aiming to investigate its possible activity in bacterial virulence. Heterologous expression of LIC11711 was performed using the pMaOri vector under regulation of the <i>lipL32</i> promoter. The protein was found mainly on the leptospiral outer surface, confirming its location. The <i>lipL32</i> promoter enhanced the expression of LIC11711 in <i>L. biflexa</i> compared to the pathogenic strain, indicating that this strategy may be used to overexpress low-copy proteins. The presence of LIC11711 enhanced the capacity of <i>L. biflexa</i> to adhere to laminin (Lam) and plasminogen (Plg)/plasmin (Pla) in vitro, suggesting the involvement of this protein in bacterial pathogenesis. We show for the first time that the expression of LIC11711 protein of <i>L. interrogans</i> confers a virulence-associated phenotype on <i>L. biflexa</i>, pointing out possible mechanisms used by pathogenic leptospires.