Peptides 24 (2003) 1099–1107 Selective toxicity of engineered lentivirus lytic peptides in a CF airway cell model Shruti M. Phadke a,∗ , Kazi Islam b , Berthony Deslouches b , Sunil A. Kapoor c , Donna Beer Stolz d , Simon C. Watkins d , Ronald C. Montelaro b , Joseph M. Pilewski d,e , Timothy A. Mietzner b a Division of Pediatric Pulmonology, The Children’s Hospital of Pittsburgh, 3705 Fifth Avenue, Pittsburgh, PA 15213, USA b Department of Molecular Genetics and Biochemistry, Pittsburgh, PA, USA c The Pediatric Lung Center, Division of Pulmonology, Fairfax, VA 22031, USA d Department of Cell Biology and Physiology, Pittsburgh, PA, USA e Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA Received 6 June 2003; accepted 22 July 2003 Abstract Lentivirus lytic peptides (LLPs) are derived from HIV-1 and have antibacterial properties. LLP derivatives (eLLPs) were engineered for greater potency against Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA). Minimum bactericidal concentration (MBC) was determined in low and physiologic salt concentrations. MBC was decreased against SA and equivalent against PA in physiologic salt when compared to the parent compound LLP1. In a novel cystic fibrosis (CF) airway cell model, one derivative, WLSA5, reduced the number of adherent PA and only moderately affected CF cell viability. Overall, eLLPs are selectively toxic to bacteria and may be useful against CF airway infections. © 2003 Elsevier Inc. All rights reserved. Keywords: Antimicrobial peptide; Cystic fibrosis; Airway epithelial cells; Selective toxicity 1. Introduction Host derived antimicrobial peptides play an important role in controlling bacterial infections, such as those as- sociated with cystic fibrosis (CF) [24]. They are secreted by macrophages and epithelial cells and are found in bi- ologically active concentrations on mucosal surfaces, par- ticularly those continually exposed to infectious pathogens [25]. The identification of many structurally diverse host derived peptides suggests that these compounds have evolved to perform optimally in a given environment against commonly encountered microbial pathogens [11]. For example, many host derived antimicrobial peptides are inhibited in the presence of high NaCl concentra- Abbreviations: ASL, airway surface liquid; BCC, Burkholderia cepa- cia complex; CF, cystic fibrosis; cfu, colony forming units; DMEM, Dulbecco’s modified Eagle medium; HPC, human placental collagen; LLPs, lentiviral lytic peptides; LLP1, lentiviral lytic peptide-1; MBC, minimum bactericidal concentration; PB, potassium phosphate buffer; R te , transepithelial resistance; TSA, tryptic soy agar ∗ Corresponding author. Tel.: +1-412-648-5630; fax: +1-412-692-6645. E-mail address: shruti.phadke@chp.edu (S.M. Phadke). tions. Antimicrobial peptides, such as human -defensin-1, are thought to be inactivated in CF airway infection be- cause this peptide functions in the low ionic environment of the normal host’s airway surface fluid [9]. Previous work [3] suggests that host defenses can be augmented to control bacterial infection through the delivery of an- timicrobial peptides. These peptides can be host derived or synthetic compounds with broad-spectrum antimicrobial activity. The lentivirus lytic peptides (LLPs) represent a newly described sequence that is similar to the group of cationic, amphipathic peptides derived from an HIV-1 transmem- brane protein with antibacterial properties [4,14,20–23]. Among the many antimicrobial peptides currently described in the literature, the -helical LLPs are structurally simi- lar to the magainins [22] and LL37, or human cathelicidin [2]. In standard broth dilution assays [21], these peptides compared favorably on a molar basis with the potency of magainin-2 or LL37. The LLPs also demonstrated broad antimicrobial activity against gram positive and negative bacteria, including those highly resistant to conventional antibiotics. Based on these findings, we have proposed that 0196-9781/$ – see front matter © 2003 Elsevier Inc. All rights reserved. doi:10.1016/j.peptides.2003.07.001