Human Neutrophil α-Defensins 1–3 Are Upregulated in the Microenvironment of Fibrotic Liver

Revisiting the potential of natural antimicrobial peptides against emerging respiratory viral disease: a review

This review assesses the antiviral capabilities of antimicrobial peptides (AMPs) against SARS-CoV-2 and other respiratory viruses, focussing on their therapeutic potential. AMPs, derived from natural sources, exhibit promising antiviral properties by disrupting viral membranes, inhibiting viral entry, and modulating host immune responses. Preclinical studies demonstrate that peptides such as defensins, cathelicidins, and lactoferrin can effectively reduce SARS-CoV-2 replication and inhibit viral spread. In addition, AMPs have shown potential in enhancing the host's antiviral immunity. Despite these promising outcomes, several challenges require assessments before transforming into clinical translation. Several issues related to peptide stability, cytotoxicity, and efficient delivery systems pose significant limitations to their therapeutic application. Recent advancements in peptide engineering, nanotechnology-based delivery systems, and peptide conjugation strategies have improved AMPs stability and bioavailability; however, further optimization is essential. Moreover, whilst AMPs are safe, their effects on host cells and tissues need a thorough investigation to minimise potential adverse reactions. This review concludes that whilst AMPs present a promising route for antiviral therapies, particularly in targeting SARS-CoV-2, extensive clinical trials and additional studies are required to overcome current limitations. Future research should focus on developing more stable, less toxic AMPs formulations with enhanced delivery mechanisms, aiming to integrate AMPs into viable therapeutic options for respiratory viral diseases, including COVID-19 and other emerging infections.

Untargeted blood serum proteomics identifies novel proteins related to neurological recovery after human spinal cord injury

BACKGROUND

The discovery of new prognostic biomarkers following spinal cord injury (SCI) is a rapidly growing field that could help uncover the underlying pathological mechanisms of SCI and aid in the development of new therapies. To date, this search has largely focused on the initial days after the lesion. However, during the subacute stage of SCI (weeks to months after the injury), there remains potential for sensorimotor recovery, and numerous secondary events develop in various organs. Additionally, the confounding effects of early interventions after the injury are less likely to interfere with the results.

METHODS

In this study, we conducted an untargeted proteomics analysis to identify biomarkers of recovery in blood serum samples during the subacute phase of SCI patients, comparing those with strong recovery to those with no recovery between 30 and 120 days. We analyzed the fraction of serum that is depleted of the most abundant proteins to unmask proteins that would otherwise go undetected. Linear models were used to identify peptides and proteins related to neurological recovery and we validated changes in some of these proteins using Enzyme-linked Immunosorbent Assay (ELISA).

RESULTS

Our findings reveal that differences in subacute recovery after SCI (from 30 to 120 days) are associated with an enrichment in proteins involved in inflammation, coagulation, and lipid metabolism. Technical validation using commercial ELISAs further confirms that high levels of SERPINE1 and ARHGAP35 are associated with strong neurological recovery, while high levels of CD300a and DEFA1 are associated with a lack of recovery.

CONCLUSIONS

Our study identifies new candidates for biomarkers of neurological recovery and for novel therapeutic targets after SCI.

Human Neutrophil Alpha-Defensins Promote NETosis and Liver Injury in Alcohol-Related Liver Cirrhosis: Potential Therapeutic Agents

Background: Neutrophils are thought to play a pivotal role in the pathogenesis of many inflammatory diseases, such as hepatitis, liver cirrhosis, etc. Activated human neutrophils release human neutrophil peptides (HNP1-3) or alpha-defensins that are antimicrobial peptides in azurophil granules. Furthermore, HNP1-3 build a scaffold of neutrophil extracellular traps (NETs) and promote the process of programmed cell death called NETosis. Our study aimed to investigate the role of alpha-defensins in the pathogenesis of alcohol-related liver cirrhosis (ALC). Methods: The concentrations of alpha-defensins in the plasma of 62 patients with ALC and 24 healthy subjects were measured by ELISA. The patients with ALC were prospectively recruited based on the severity of liver dysfunction according to the Child-Pugh and Model of End-Stage Liver Disease-Natrium (MELD-Na) scores, modified Maddrey's Discriminant Function (mDF), and the presence of ALC complications. Results: The concentrations of alpha-defensins in plasma were significantly higher in the ALC patients than in the controls. The plasma levels of HNP1-3 correlated with the MELD and mDF scores. ALC subgroups with MELD > 20 and mDF > 32 displayed significantly higher HNP1-3 concentrations. The plasma levels of HNP1-3 revealed a good predictive AUC for hepatic encephalopathy and ascites development (0.81 and 0.74, respectively) and for patient survival (0.87) in those over 40 years of age. Conclusion: These findings suggest that alpha-defensins play an important role in the assessment of ALC.