Antiviral activity of cathelicidin 5, a peptide from Alligator sinensis, against WSSV in caridean shrimp Exopalaemon modestus

A non-Bactericidal Cathelicidin with Antioxidant Properties Ameliorates UVB-Induced Mouse Skin Photoaging via Intracellular ROS Scavenging and Keap1/Nrf2 Pathway Activation

Cathelicidins, a category of critical host defense molecules in vertebrates, have been extensively studied for their bactericidal functions, but little is known about their non-bactericidal properties. Herein, a novel cathelicidin peptide (Atonp2) was identified from the plateau frog Nanorana ventripunctata. It did not exhibit bactericidal activity but showed significant therapeutic effects in chronic UVB radiation-induced mouse skin photoaging through inhibiting thickening, pyroptosis and inflammation in the epidermis, while inhibiting cellular senescence, collagen fibre breakage and type Ⅰ collagen reduction in the dermis. Further studies indicated that Atonp2 effectively scavenged UVB-induced intracellular ROS via tyrosines at positions 9 and 10, while activating the Keap1/Nrf2 pathway to protect epidermal keratinocytes against UVB radiation, which in turn indirectly reversed the senescence and collagen degradation of dermal fibroblasts, thereby ameliorating UVB-induced skin photoaging. As such, this study identified a non-bactericidal cathelicidin peptide with potent antioxidant functions, highlighting its potential to treat and prevent skin photoaging.

Evaluation of potential antiviral activities of antimicrobial peptides in fish mucus

BACKGROUND

Fish skin mucus contains innate immune factors and acts as the first line of physical or chemical defense against pathogens.

OBJECTIVE

The primary aim of this study was to determine the antiviral activity of sea bream (SBr), rainbow trout (RT), and sea bass (SBa) fish skin mucus against herpes simplex virus (HSV)-1. In addition, it was aimed to associate possible antiviral activity with antimicrobial peptides (AMPs) such as cathelicidin, hepcidin, galectin 2, and C10ORF99, whose levels were determined in the mucus.

METHODS

The antiviral activity and oxidative/antioxidant status of mucus against HSV-1 virus was evaluated. In addition, AMPs, SOD, and CAT activities, and immunoglobulin M levels were also analyzed in mucus of fish.

RESULTS

Antiviral activity mucus of SBr, RT, and SBa against HSV-1 were determined as 2-4, 2-5, and 2-2, respectively. The higher antiviral activity of SBr and RT mucus compared to the mucus of SBa can be associated with higher AMP levels in them.

CONCLUSION

The skin mucus of SBr and RT may be nutritional supplement, adjuvant, and a new agent that can potentiate the effects of antimicrobial/antiviral agents.

Immunostimulants for shrimp aquaculture: paving pathway towards shrimp sustainability

At present, food security is a matter of debate of global magnitude and fulfilling the feeding requirement of > 8 billion human populations by 2030 is one of the major concerns of the globe. Aquaculture plays a significant role to meet the global food requirement. Shrimp species such as Litopenaeus vannamei, Penaeus monodon, and Macrobrachium rosenbergii are among the most popular food commodities worldwide. As per Global Outlook for Aquaculture Leadership survey, disease outbreaks have been a matter of concern from the past many decades regarding the shrimp aquaculture production. Among the past disease outbreaks, white spot disease caused by the white spot syndrome virus is considered to be one of the most devastating ones that caused colossal losses to the shrimp industry. Since the virus is highly contagious, it spreads gregariously among the shrimp population; hence, practicing proper sanitization practices is crucial in order to have disease-free shrimps. Additionally, in order to control the disease, antibiotics were used that further leads to bioaccumulation and biomagnification of antibiotics in several food webs. The bioaccumulation of the toxic residues in the food webs further adversely affected human too. Recently, immunostimulants/antivirals were used as an alternative to antibiotics. They were found to enhance the immune system of shrimps in eco-friendly manner. In context to this, the present paper presents a critical review on the immunostimulants available from plants, animals, and chemicals against WSSV in shrimps. Looking into this scenario, maintaining proper sanitation procedures in conjunction with the employment of immunostimulants may be a viable approach for preserving shrimp aquaculture across the globe.

Novel Alligator Cathelicidin As-CATH8 Demonstrates Anti-Infective Activity against Clinically Relevant and Crocodylian Bacterial Pathogens

Host defense peptides (HDPs) represent an alternative way to address the emergence of antibiotic resistance. Crocodylians are interesting species for the study of these molecules because of their potent immune system, which confers high resistance to infection. Profile hidden Markov models were used to screen the genomes of four crocodylian species for encoded cathelicidins and eighteen novel sequences were identified. Synthetic cathelicidins showed broad spectrum antimicrobial and antibiofilm activity against several clinically important antibiotic-resistant bacteria. In particular, the As-CATH8 cathelicidin showed potent in vitro activity profiles similar to the last-resort antibiotics vancomycin and polymyxin B. In addition, As-CATH8 demonstrated rapid killing of planktonic and biofilm cells, which correlated with its ability to cause cytoplasmic membrane depolarization and permeabilization as well as binding to DNA. As-CATH8 displayed greater antibiofilm activity than the human cathelicidin LL-37 against methicillin-resistant Staphylococcus aureus in a human organoid model of biofilm skin infection. Furthermore, As-CATH8 demonstrated strong antibacterial effects in a murine abscess model of high-density bacterial infections against clinical isolates of S. aureus and Acinetobacter baumannii, two of the most common bacterial species causing skin infections globally. Overall, this work expands the repertoire of cathelicidin peptides known in crocodylians, including one with considerable therapeutic promise for treating common skin infections.

Cathelicidin-NV from Nanorana ventripunctata effectively protects HaCaT cells, ameliorating ultraviolet B-induced skin photoaging

Cathelicidins are diverse effector molecules in the vertebrate immune system and are related to immune regulation, inflammatory response, wound healing, and blood vessel formation. However, little is known about their free radical scavenging ability, especially in vivo. In this study, a cathelicidin molecule (cathelicidin-NV, ARGKKECKDDRCRLLMKRGSFSYV) previously identified from the spot-bellied plateau frog (Nanorana ventripunctata) (Anura, Dicroglossidae, Dicroglossinae) by us was shown to alleviate ultraviolet B (UVB)-induced skin photoaging in mice. Cathelicidin-NV effectively suppressed cytotoxicity, DNA fragmentation, apoptosis and reduced the protein expression levels of JNK, c-Jun, and MMP-1, which are involved in the regulation of collagen degradation in HaCaT cells induced by UVB irradiation. Furthermore, cathelicidin-NV also scavenged UVB-induced intracellular reactive oxygen species (ROS). Taken together, cathelicidin-NV directly scavenged excessive intracellular ROS to protect HaCaT cells, and subsequently alleviated UVB-induced skin photoaging. This study extends reports on the antioxidant function of the cathelicidin family. In addition, the properties of cathelicidin-NV make it an excellent candidate for the prevention and treatment of UV-induced skin photoaging.