Pretreatment with cathelicidin-BF ameliorates Pseudomonas aeruginosa pneumonia in mice by enhancing NETosis and the autophagy of recruited neutrophils and macrophages

Dysregulation of neutrophil in sepsis: recent insights and advances

Sepsis remains the leading cause of death in intensive care units. Despite newer antimicrobial and supportive therapies, specific treatments are still lacking. Neutrophils are pivotal components of the effector phase of the host immune defense against pathogens and play a crucial role in the control of infections under normal circumstances. In addition to its anti-infective effects, the dysregulation and overactivation of neutrophils may lead to severe inflammation or tissue damage and are potential mechanisms for poor prognosis in sepsis. This review focuses on recent advancements in the understanding of the functional status of neutrophils across various pathological stages of sepsis to explore the mechanisms by which neutrophils participate in sepsis progression and provide insights for the treatment of sepsis by targeting neutrophils.

Antimicrobial peptides: An alternative strategy to combat antimicrobial resistance

Antimicrobial peptides (AMPs) are a diverse group of naturally occurring molecules produced by eukaryotes and prokaryotes. They have an important role in innate immunity via their direct microbicidal properties or immunomodulatory activities against pathogens. With the widespread occurrence of antimicrobial resistance (AMR), AMPs are considered as viable alternatives for the treatment of multidrug-resistant microbes, inflammation, and, wound healing. The broad-spectrum antibacterial activity of AMPs is predominantly attributed to membrane disruption, leading to the formation of transmembrane pores and, eventually, cell lysis. However, mechanisms related to inhibition of cell wall synthesis, nucleic acid synthesis, protein synthesis, or enzymatic activity are also associated with these peptides. In this review, we discuss our current understanding, therapeutic uses and challenges associated with the clinical applications of AMPs.

Hyaluronan Scaffold Decorated with Bifunctional Peptide Promotes Wound Healing via Antibacterial and Anti-Inflammatory

The invasion of bacteria and inflammation impeded infected wounds heal. Here, a hyaluronan-based scaffold (HAG-g-C) was designed by cross-linking with gallic acid-modified gelatin to provide a protein microenvironment and decorated with cathelicidin-BF (CBF), a natural antimicrobial peptide, to remove bacterial infections and reverse the inflammatory environment. In vitro, HAG-g-C presented an antibacterial effect on Staphylococcus aureus and Escherichia coli. Meanwhile, it could drive the phenotypic switch of macrophage from M1 to M2 to accelerate tissue remodeling. In a mouse model of S. aureus-infected total skin defects, HAG-g-C inhibited the process of infection at the beginning of the wound and then regulated the M1 macrophage transformed to M2 phenotype on day 12. In addition, HAG-g-C induced collagen deposition, and reduced the expression of TNF-α, thereby significantly accelerating the reconstruction of infected wounds.

Antimicrobial peptides: Opportunities and challenges in overcoming resistance

Antibiotic resistance represents a global health threat, challenging the efficacy of traditional antimicrobial agents and necessitating innovative approaches to combat infectious diseases. Among these alternatives, antimicrobial peptides have emerged as promising candidates against resistant pathogens. Unlike traditional antibiotics with only one target, these peptides can use different mechanisms to destroy bacteria, with low toxicity to mammalian cells compared to many conventional antibiotics. Antimicrobial peptides (AMPs) have encouraging antibacterial properties and are currently employed in the clinical treatment of pathogen infection, cancer, wound healing, cosmetics, or biotechnology. This review summarizes the mechanisms of antimicrobial peptides against bacteria, discusses the mechanisms of drug resistance, the limitations and challenges of AMPs in peptide drug applications for combating drug-resistant bacterial infections, and strategies to enhance their capabilities.

A snake cathelicidin enhances transcription factor EB-mediated autophagy and alleviates ROS-induced pyroptosis after ischaemia-reperfusion injury of island skin flaps

BACKGROUND AND PURPOSE

Ischaemia-reperfusion (I/R) injury is a major contributor to skin flap necrosis, which presents a challenge in achieving satisfactory therapeutic outcomes. Previous studies showed that cathelicidin-BF (BF-30) protects tissues from I/R injury. In this investigation, BF-30 was synthesized and its role and mechanism in promoting survival of I/R-injured skin flaps explored.

EXPERIMENTAL APPROACH

Survival rate analysis and laser Doppler blood flow analysis were used to evaluate I/R-injured flap viability. Western blotting, immunofluorescence, TdT-mediated dUTP nick end labelling (TUNEL) and dihydroethidium were utilized to examine the levels of apoptosis, pyroptosis, oxidative stress, transcription factor EB (TFEB)-mediated autophagy and molecules related to the adenosine 5'-monophosphate-activated protein kinase (AMPK)-transient receptor potential mucolipin 1 (TRPML1)-calcineurin signalling pathway.

KEY RESULTS

The outcomes revealed that BF-30 enhanced I/R-injured island skin flap viability. Autophagy, oxidative stress, pyroptosis and apoptosis were related to the BF-30 capability to enhance I/R-injured flap survival. Improved autophagy flux and tolerance to oxidative stress promoted the inhibition of apoptosis and pyroptosis in vascular endothelial cells. Activation of TFEB increased autophagy and inhibited endothelial cell oxidative stress in I/R-injured flaps. A reduction in TFEB level led to a loss of the protective effect of BF-30, by reducing autophagy flux and increasing the accumulation of reactive oxygen species (ROS) in endothelial cells. Additionally, BF-30 modulated TFEB activity via the AMPK-TRPML1-calcineurin signalling pathway.

CONCLUSION AND IMPLICATIONS

BF-30 promotes I/R-injured skin flap survival by TFEB-mediated up-regulation of autophagy and inhibition of oxidative stress, which may have possible clinical applications.

Microenvironment responsive charge-switchable nanoparticles act on biofilm eradication and virulence inhibition for chronic lung infection treatment

Chronic pulmonary infection caused by Pseudomonas aeruginosa (P. aeruginosa) is a common lung disease with high mortality, posing severe threats to public health. Highly resistant biofilm and intrinsic resistance make P. aeruginosa hard to eradicate, while powerful virulence system of P. aeruginosa may give rise to the recurrence of infection and eventual failure of antibiotic therapy. To address these issues, infection-microenvironment responsive nanoparticles functioning on biofilm eradication and virulence inhibition were simply prepared by electrostatic complexation between dimethylmaleic anhydride (DA) modified negatively charged coating and epsilon-poly(l-lysine) derived cationic nanoparticles loaded with azithromycin (AZI) (DA-AZI NPs). Charge reversal responsive to acidic condition enabled DA-AZI NPs to successively penetrate through both mucus and biofilms, followed by targeting to P. aeruginosa and permeabilizing its outer/inner membrane. Then in situ released AZI, which was induced by the lipase-triggered NPs dissociation, could easily enter into bacteria to take effects. DA-AZI NPs exhibited enhanced eradication activity against P. aeruginosa biofilms with a decrease of >99.999% of bacterial colonies, as well as remarkable inhibitory effects on the production of virulence factors and bacteria re-adhesion & biofilm re-formation. In a chronic pulmonary infection model, nebulization of DA-AZI NPs into infected mice resulted in prolonged retention and increased accumulation of the NPs in the infected sites of the lungs. Moreover, they significantly reduced the burden of P. aeruginosa, effectively alleviating lung tissue damages and inflammation. Overall, the proposed DA-AZI NPs highlight an innovative strategy for treating chronic pulmonary infection.

The Contribution of Antimicrobial Peptides to Immune Cell Function: A Review of Recent Advances

The development of novel antimicrobial agents to replace antibiotics has become urgent due to the emergence of multidrug-resistant microorganisms. Antimicrobial peptides (AMPs), widely distributed in all kingdoms of life, present strong antimicrobial activity against a variety of bacteria, fungi, parasites, and viruses. The potential of AMPs as new alternatives to antibiotics has gradually attracted considerable interest. In addition, AMPs exhibit strong anticancer potential as well as anti-inflammatory and immunomodulatory activity. Many studies have provided evidence that AMPs can recruit and activate immune cells, controlling inflammation. This review highlights the scientific literature focusing on evidence for the anti-inflammatory mechanisms of different AMPs in immune cells, including macrophages, monocytes, lymphocytes, mast cells, dendritic cells, neutrophils, and eosinophils. A variety of immunomodulatory characteristics, including the abilities to activate and differentiate immune cells, change the content and expression of inflammatory mediators, and regulate specific cellular functions and inflammation-related signaling pathways, are summarized and discussed in detail. This comprehensive review contributes to a better understanding of the role of AMPs in the regulation of the immune system and provides a reference for the use of AMPs as novel anti-inflammatory drugs for the treatment of various inflammatory diseases.

Antimicrobial peptides for combating drug-resistant bacterial infections

The problem of drug resistance due to long-term use of antibiotics has been a concern for years. As this problem grows worse, infections caused by multiple bacteria are expanding rapidly and are extremely detrimental to human health. Antimicrobial peptides (AMPs) are a good alternative to current antimicrobials with potent antimicrobial activity and unique antimicrobial mechanisms, which have advantages over traditional antibiotics in fighting against drug-resistant bacterial infections. Currently, researchers have conducted clinical investigations on AMPs for drug-resistant bacterial infections while integrating new technologies in the development of AMPs, such as changing amino acid structure of AMPs and using different delivery methods for AMPs. This article introduces the basic properties of AMPs, deliberates the mechanism of drug resistance in bacteria and the therapeutic mechanism of AMPs. The current disadvantages and advances of AMPs in combating drug-resistant bacterial infections are also discussed. This article provides important insights into the research and clinical application of new AMPs for drug-resistant bacterial infections.

Past, Present, and Future of Naturally Occurring Antimicrobials Related to Snake Venoms

This review focuses on proteins and peptides with antimicrobial activity because these biopolymers can be useful in the fight against infectious diseases and to overcome the critical problem of microbial resistance to antibiotics. In fact, snakes show the highest diversification among reptiles, surviving in various environments; their innate immunity is similar to mammals and the response of their plasma to bacteria and fungi has been explored mainly in ecological studies. Snake venoms are a rich source of components that have a variety of biological functions. Among them are proteins like lectins, metalloproteinases, serine proteinases, L-amino acid oxidases, phospholipases type A₂, cysteine-rich secretory proteins, as well as many oligopeptides, such as waprins, cardiotoxins, cathelicidins, and β-defensins. In vitro, these biomolecules were shown to be active against bacteria, fungi, parasites, and viruses that are pathogenic to humans. Not only cathelicidins, but all other proteins and oligopeptides from snake venom have been proteolyzed to provide short antimicrobial peptides, or for use as templates for developing a variety of short unnatural sequences based on their structures. In addition to organizing and discussing an expressive amount of information, this review also describes new β-defensin sequences of Sistrurus miliarius that can lead to novel peptide-based antimicrobial agents, using a multidisciplinary approach that includes sequence phylogeny.

Pretreatment with 3-methyladenine ameliorated Pseudomonas aeruginosa-induced acute pneumonia by inhibiting cell death of neutrophils in a mouse infection model

Pseudomonas aeruginosa is one of the leading causes of nosocomial infections worldwide. Clinical isolates that are resistant to multiple antimicrobials make it intractable. The interactions between P. aeruginosa and host cell death have multiple effects on bacterial clearance and inflammation; however, the potential intervention effects remain to be defined. Herein, we demonstrated that intravenous administration of 3-methyladenine before, but not after, P. aeruginosa infection enhanced autophagy-independent survival, which was accompanied by a decrease in the bacterial load, alleviation of pathology and reduction in inflammatory cytokines, in an acute pneumonia mouse model. Interestingly, these beneficial effects were not dependent on neutrophil recruitment or phagocytosis, but on the enhanced killing capacity induced by inhibiting the cell death of 3-MA pretreated neutrophils. These findings demonstrate a novel protective role of 3-MA pretreatment in P. aeruginosa-induced acute pneumonia.

Autophagy-driven neutrophil extracellular traps: The dawn of sepsis

Sepsis is a systemic inflammatory syndrome caused by infection disorders. The core mechanism of sepsis is immune dysfunction. Neutrophils are the most abundant circulating white blood cells, which play a crucial role in mediating the innate immune response. Previous studies have shown that an effective way to treat sepsis is through the regulation of neutrophil functions. Autophagy, a highly conserved degradation process, is responsible for removing denatured proteins or damaged organelles within cells and protecting cells from external stimuli. It is a key homeostasis process that promotes neutrophil function and differentiation. Autophagy has been shown to be closely associated with inflammation and immunity. Neutrophils, the first line of innate immunity, migrate to inflammatory sites upon their activation. Neutrophil-mediated autophagy may participate in the clinical course of sepsis. In this review, we summarized and analyzed the latest research findings on the changes in neutrophil external traps during sepsis, the regulatory role of autophagy in neutrophil, and the potential application of autophagy-driven NETs in sepsis, so as to guide clinical treatment of sepsis.

Antimicrobial Peptides: A Potent Alternative to Antibiotics

Antimicrobial peptides constitute one of the most promising alternatives to antibiotics since they could be used to treat bacterial infections, especially those caused by multidrug-resistant pathogens. Many antimicrobial peptides, with various activity spectra and mechanisms of actions, have been described. This review focuses on their use against ESKAPE bacteria, especially in biofilm treatments, their synergistic activity, and their application as prophylactic agents. Limitations and challenges restricting therapeutic applications are highlighted, and solutions for each challenge are evaluated to analyze whether antimicrobial peptides could replace antibiotics in the near future.

P. aeruginosa Mediated Necroptosis in Mouse Tumor Cells Induces Long-Lasting Systemic Antitumor Immunity

Necroptosis is a form of programmed cell death (PCD) characterized by RIP3 mediated MLKL activation and increased membrane permeability via MLKL oligomerization. Tumor cell immunogenic cell death (ICD) has been considered to be essential for the anti-tumor response, which is associated with DC recruitment, activation, and maturation. In this study, we found that P. aeruginosa showed its potential to suppress tumor growth and enable long-lasting anti-tumor immunity in vivo. What's more, phosphorylation- RIP3 and MLKL activation induced by P. aeruginosa infection resulted in tumor cell necrotic cell death and HMGB1 production, indicating that P. aeruginosa can cause immunogenic cell death. The necrotic cell death can further drive a robust anti-tumor response via promoting tumor cell death, inhibiting tumor cell proliferation, and modulating systemic immune responses and local immune microenvironment in tumor. Moreover, dying tumor cells killed by P. aeruginosa can catalyze DC maturation, which enhanced the antigen-presenting ability of DC cells. These findings demonstrate that P. aeruginosa can induce immunogenic cell death and trigger a robust long-lasting anti-tumor response along with reshaping tumor microenvironment.

Streptococcus pneumoniae PepO promotes host anti-infection defense via autophagy in a Toll-like receptor 2/4 dependent manner

Macrophage is essential for host anti-bacterial defense by directly eliminating invading microbes and inducing a series of immune reactions. Here we identified a Streptococcus pneumoniae protein, PepO, as a TLR2/TLR4 bi-ligand. We found that PepO enhances macrophage unspecific phagocytosis and bactericidal activity, which is related to the induction of autophagy in macrophage, for the inhibition of autophagy significantly decreased the phagocytosis and bactericidal activity of PepO-treated macrophage. We confirmed that these effects of PepO are dependent on interacting with both TLR2 and TLR4. The tlr2 or tlr4 deficiency partially abolished the effect of PepO while tlr2/tlr4 deficiency abolished it completely. In vivo study demonstrated that PepO reduced the bacteria load in WT mice significantly, while the depletion of macrophage or tlr2/tlr4 deficiency abrogated the effect of PepO. Our findings suggested the therapeutic potential of PepO and provided experimental evidence for immunotherapy against infectious disease.

ARHGAP24 ameliorates inflammatory response through inactivating Rac1/Akt/NF-κB pathway in acute pneumonia model of rat

Background

ARHGAP24 might play a protective effect in the development of acute pneumonia, but the underlying mechanism remained a mystery. We aimed to investigate the effect of ARHGAP24 and explore the protective mechanism based on the acute pneumonia model of rats.

Methods

Western blotting analysis was conducted to measure the expression of ARHGAP24 in the rat model of bacillus pyocyaneus-induced acute pneumonia after 12, 24, 36, and 48 h modeling. In the acute pneumonia model of rat, lung histopathological change, lung edema, and levels of inflammatory cytokines in the broncho alveolar lavage fluid (BALF) were respectively measured to comprehensively evaluate the beneficial effect of overexpression of ARHGAP24 mediated by adenovirus. The western blotting analysis was conducted to evaluate Rac1/Akt/NF-κB pathway-related protein expression change with ARHGAP24 overexpression.

Results

We found that ARHGAP24 expression tended to be lower in the acute pneumonia model of the rat after bacillus pyocyaneus treated 12, 24, 36, and 48 h. High expression of ARHGAP24 and a substantial ARHGAP24 positive area was found in the western blotting analysis and immunohistochemical staining in rats transfected with ARHGAP24. In the meantime, overexpression of ARHGAP24 suppressed the development of acute pneumonia through alleviating lung histopathological deterioration, lung edema, and levels of inflammatory cytokines in the BALF of the lung. What is more critical, ARHGAP24 overexpression inhibits the activation of Rac1, Akt, and NF-κB.

Conclusions

Thus, we conclude that ARHGAP24 ameliorated the inflammatory response in the acute pneumonia model of the rat through inactivating the Rac1/Akt/NF-κB pathway.

Cathelicidin Host Defense Peptides and Inflammatory Signaling: Striking a Balance

Host-defense peptides (HDPs) are vital components of innate immunity in all vertebrates. While their antibacterial activity toward bacterial cells was the original focus for research, their ability to modulate immune and inflammatory processes has emerged as one of their major functions in the host and as a promising approach from which to develop novel therapeutics targeting inflammation and innate immunity. In this review, with particular emphasis on the cathelicidin family of peptides, the roles of natural HDPs are examined in managing immune activation, cellular recruitment, cytokine responses, and inflammation in response to infection, as well as their contribution(s) to various inflammatory disorders and autoimmune diseases. Furthermore, we discuss current efforts to develop synthetic HDPs as therapeutics aimed at restoring balance to immune responses that are dysregulated and contribute to disease pathologies.

Pulmonary Staphylococcus aureus infection regulates breast cancer cell metastasis via neutrophil extracellular traps (NETs) formation

The formation of neutrophil extracellular traps (NETs) was recently identified as one of the most important processes for the maintenance of host tissue homeostasis in bacterial infection. Meanwhile, pneumonia infection has a poor effect on cancer patients receiving immunotherapy. Whether pneumonia‐mediated NETs increase lung metastasis remains unclear. In this study, we identified a critical role for multidrug‐resistant Staphylococcus aureus infection‐induced NETs in the regulation of cancer cell metastasis. Notably, S. aureus triggered autophagy‐dependent NETs formation in vitro and in vivo and increased cancer cell metastasis. Targeting autophagy effectively regulated NETs formation, which contributed to the control of cancer metastasis in vivo. Moreover, the degradation of NETs by DNase I significantly suppresses metastasis in lung. Our work offers novel insight into the mechanisms of metastasis induced by bacterial pneumonia and provides a potential therapeutic strategy for pneumonia‐related metastasis.

Neutrophil Extracellular Traps (NETs) and Damage-Associated Molecular Patterns (DAMPs): Two Potential Targets for COVID-19 Treatment

COVID-19 is a pandemic disease caused by the new coronavirus SARS-CoV-2 that mostly affects the respiratory system. The consequent inflammation is not able to clear viruses. The persistent excessive inflammatory response can build up a clinical picture that is very difficult to manage and potentially fatal. Modulating the immune response plays a key role in fighting the disease. One of the main defence systems is the activation of neutrophils that release neutrophil extracellular traps (NETs) under the stimulus of autophagy. Various molecules can induce NETosis and autophagy; some potent activators are damage-associated molecular patterns (DAMPs) and, in particular, the high-mobility group box 1 (HMGB1). This molecule is released by damaged lung cells and can induce a robust innate immunity response. The increase in HMGB1 and NETosis could lead to sustained inflammation due to SARS-CoV-2 infection. Therefore, blocking these molecules might be useful in COVID-19 treatment and should be further studied in the context of targeted therapy.

Hitchhiking with Nature: Snake Venom Peptides to Fight Cancer and Superbugs

Abstract

For decades, natural products in general and snake venoms (SV) in particular have been a rich source of bioactive compounds for drug discovery, and they remain a promising substrate for therapeutic development. Currently, a handful of SV-based drugs for diagnosis and treatment of various cardiovascular disorders and blood abnormalities are on the market. Likewise, far more SV compounds and their mimetics are under investigation today for diverse therapeutic applications, including antibiotic-resistant bacteria and cancer. In this review, we analyze the state of the art regarding SV-derived compounds with therapeutic potential, focusing on the development of antimicrobial and anticancer drugs. Specifically, information about SV peptides experimentally validated or predicted to act as antimicrobial and anticancer peptides (AMPs and ACPs, respectively) has been collected and analyzed. Their principal activities both in vitro and in vivo, structures, mechanisms of action, and attempts at sequence optimization are discussed in order to highlight their potential as drug leads.

Key Contribution

This review describes the state of the art in snake venom-derived peptides and their therapeutic applications. This work reinforces the potential of snake venom components as therapeutic agents, particularly in the quest for new antimicrobial and anticancer drugs.

Autophagy-driven NETosis is a double-edged sword - Review

Autophagy is a cellular mechanism responsible for delivering protein aggregates or damaged organelles to lysosomes for degradation. It is also simultaneously a precise regulatory process, which is crucial for dealing with hunger, oxidative stress, and pathogen defense. Neutrophil Extracellular Traps (NETs), which form a part of a newly described bactericidal process, are reticular structures composed of a DNA backbone and multiple functional proteins, formed via a process known as NETosis. NETs exert their anti-infection activity by capturing pathogenic microorganisms, inhibiting their spread and inactivating virulence factors. However, NETs may also activate an immune response in non-infectious diseases, leading to tissue damage. Although the mechanism underlying this phenomenon is unclear, a large number of studies have suggested that autophagy may be involved. Autophagy-mediated NETs not only induce inflammation and tissue damage, but can also lead to cell senescence, malignant transformation, and cell death. Autophagy-dependent NETs also play a beneficial role in the hostwith respect to pathogen clearance and immune defense. Through careful review of the literature, we have found that the distinct roles of autophagy in NETosis may be dependent on the extent of autophagy and the specific manner in which it was induced. This article summarizes numerous recent studies, and reviews the role of autophagy-driven NETosis in various diseases, in the hope that this will lead to the development of more effective treatments.

Autophagy, an important therapeutic target for pulmonary fibrosis diseases

As an evolutionarily conserved intracellular degradation pathway, autophagy is essential to cellular homeostasis. Several studies have demonstrated that autophagy showed an important effect on some pulmonary fibrosis diseases, including idiopathic pulmonary fibrosis (IPF), cystic fibrosis lung disease, silicosis and smoking-induced pulmonary fibrosis. For example, autophagy mitigates the pathological progression of IPF by regulating the apoptosis of fibroblasts and the senescence of alveolar epithelial cells. In addition, autophagy ameliorates cystic fibrosis lung disease via rescuing transmembrane conductance regulators (CFTRs) to the plasma membrane. Furthermore, autophagy alleviates the silica-induced pulmonary fibrosis by decreasing apoptosis of alveolar epithelial cells in silicosis. However, excessive macrophage autophagy aggravates the pathogenesis of silicosis fibrosis by promoting the proliferation and migration of lung fibroblasts in silicosis. Autophagy is also involved in smoking-induced pulmonary fibrosis, coal workers' pneumoconiosis, ionizing radiation-mediated pulmonary fibrosis and heavy metal nanoparticle-mediated pulmonary fibrosis. In this review, the role and signalling mechanisms of autophagy in the progression of pulmonary fibrosis diseases have been systematically analysed. It has provided a new insight into the therapeutic potential associated with autophagy in pulmonary fibrosis diseases. In conclusion, the targeting of autophagy might prove to be a prospective avenue for the therapeutic intervention of pulmonary fibrosis diseases.

Potential role of the antimicrobial peptide Tachyplesin III against multidrug-resistant P. aeruginosa and A. baumannii coinfection in an animal model

Background

Tachyplesin III, an antimicrobial peptide (AMP), provides protection against multidrug-resistant (MDR) bacterial infections and shows cytotoxicity to mammalian cells. Mixed bacterial infections, of which P. aeruginosa plus A. baumannii is the most common and dangerous combination, are critical contributors to the morbidity and mortality of long-term in-hospital respiratory medicine patients. Therefore, the development of effective therapeutic approaches to mixed bacterial infections is urgently needed.

Methods and results

In this study, we demonstrated that compared with individual infections, mixed infections with MDR bacteria P. aeruginosa and A. baumannii cause more serious diseases, with increased pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and chemokines (MCP-1/MIP-2) and reduced mouse survival. In vitro treatment with Tachyplesin III enhanced phagocytosis in a mouse alveolar macrophage cell line (MH-S). Strikingly, in vivo, Tachyplesin III demonstrated a potential role against mixed-MDR bacterial coinfection. The bacterial burden in bronchoalveolar lavage fluid (BALF) was significantly reduced in the Tachyplesin III-treated group. In addition, a systemic reduction in pro-inflammatory cytokines and decreased lung injury occurred with Tachyplesin III therapy.

Conclusion

Therefore, our study demonstrated that Tachyplesin III represents a potential therapeutic treatment against mixed-MDR bacterial infection in vivo, which sheds light on the development of therapeutic strategies against mixed-MDR bacterial infections.