Sea snake cathelicidin (Hc-cath) exerts a protective effect in mouse models of lung inflammation and infection

Abstract

We investigated the anti-inflammatory and antibacterial activities of Hc-cath, a cathelicidin peptide derived from the venom of the sea snake, Hydrophis cyanocyntus , using in vivo models of inflammation and infection. Hc-cath function was evaluated in in vitro , in vivo in the wax moth, Galleria mellonella , and in mouse models of intraperitoneal and respiratory Pseudomonas aeruginosa infection. Hc-Cath downregulated LPS-induced pro-inflammatory responses in macrophages and significantly improved the survival of P. aeruginosa infected G. mellonella over a 5-day period. We also demonstrated, for the first time, that Hc-cath can modulate inflammation in a mouse model of LPS-induced lung inflammation by significantly reducing the release of the pro-inflammatory cytokine and neutrophil chemoattractant, KC, resulting in reduced cellular infiltration into the lungs. Moreover, Hc-cath treatment significantly reduced the bacterial load and inflammation in mouse models of P. aeruginosa intraperitoneal and respiratory infection. The effect of Hc-cath in our studies highlights the potential to develop this peptide as a candidate for therapeutic development.

Cell-Penetrating Peptides Derived from Animal Venoms and Toxins

“…The antimicrobial activity ranges from multidrug-resistant clinical isolates to life-threatening viruses, as reported for cathelicidin-OH30 derived from the venom of the king cobra Ophiophagus hannah, as well as venom cathelicidin-BF30 and short derivatives from the banded krait Bungarus fasciatus venom [ 158 , 159 ]. The anti-inflammatory properties of venom cathelicidins have also been observed in in vitro and in vivo models of inflammation for cathelicidin-BF30 [ 160 ] and for CRAMPs from the venom of the blue-banded sea snake Hydrophis cyanocyntus, demonstrating the potent antimicrobial activity, associated with immunomodulatory effects of snake venom cathelicidins [ 161 , 162 ]. Short peptide fragments of snake venom cathelicidins have been prepared, displaying different levels of activity and efficacy against a range of microbes, including viruses [ 163 ], multidrug-resistant bacteria, pathogenic yeasts and biofilms [ 164 , 165 , 166 , 167 ].…”

The Impact of Lung Proteases on Snake-Derived Antimicrobial Peptides

“…THP-1 cells (human acute monocytic leukaemia cells) were purchased from the European Collection of Authentic Cell Culture (ECACC) and maintained at cell density of 2-9 × 10 5 cells/mL in Roswell Park Memorial Institute (RPMI) 1640 medium (Thermo Fisher Scientific, Loughborough, UK) supplemented with 10% heat-inactivated foetal bovine serum (FBS) (Thermo Fisher Scientific, Loughborough, UK) and 2 mM L-glutamine (Thermo Fisher Scientific, Loughborough, UK) in a humidified incubator with 5% CO 2 at 37 • C [22]. A previously described method of LPS-induced inflammation using THP-1 monocyte-derived macrophages was employed to assess the anti-inflammatory activity of the peptides [19]. THP-1 cells were seeded at a density of 2.5 × 10 5 cells/well in a 24-well plate (Thermo Fisher Scientific, Loughborough, UK) and differentiated to THP-1 monocytederived macrophages by culturing under standard cell culture conditions (37 • C/5% CO 2 ) in the presence of 160 nM phorbol 12-myristate 13-acetate (PMA) (Merck, Gillingham, UK) for 72 h. The cell supernatant was replaced with 1 mL of fresh media and incubated for a further 24 h prior to experimentation.…”

“…While Sn1 has been shown to inhibit the LPS-induced inflammatory response via direct LPS binding and via binding to the myeloid differentiation protein-2 (MD2) of the Toll-like receptor 4 (TLR4)-MD2 complex, an exact mechanism has not been established for SnE1 or SnV1 [14]. Furthermore, our group previously reported that Sn1 held therapeutic potential for infection due to antimicrobial and anti-inflammatory effects observed in vivo [19]. Thus, assessing the therapeutic potential of these snake-derived peptides in the context of inflammatory lung disease was of interest due to their antimicrobial and/or immunomodulatory properties.…”

The PDZ motif peptide of ZO-1 attenuates Pseudomonas aeruginosa LPS-induced airway inflammation

“…Pseudomonas aeruginosa is an ordinary gram-negative, encapsulated, rod-shaped bacterium that can induce severe diseases in humans. In particular, respiratory infection is representative of a major clinical problem globally and has major consequences for patients 1 . Respiratory infections are more lethal for patients with inflammatory conditions, such as asthma or COPD, therefore, studies examining the negative control mechanisms of P. aeruginosa -induced diseases are critical to the development of novel therapeutic medications.…”