Heterologous Expression of Biologically Active Porcine Lactoferrin in Pichia Pastoris Yeast

Anti-fungal peptides: an emerging category with enthralling therapeutic prospects in the treatment of candidiasis

Candida infections, particularly invasive candidiasis, pose a serious global health threat. Candida albicans is the most prevalent species causing candidiasis, and resistance to key antifungal drugs, such as azoles, echinocandins, polyenes, and fluoropyrimidines, has emerged. This growing multidrug resistance (MDR) complicates treatment options, highlighting the need for novel therapeutic approaches. Antifungal peptides (AFPs) are gaining recognition for their potential as new antifungal agents due to their diverse structures and functions. These natural or recombinant peptides can effectively target fungal virulence and viability, making them promising candidates for future antifungal development. This review examines infections caused by Candida species, the limitations of current antifungal treatments, and the therapeutic potential of AFPs. It emphasizes the importance of identifying novel AFP targets and their production for advancing treatment strategies. By discussing the therapeutic development of AFPs, the review aims to draw researchers' attention to this promising field. The integration of knowledge about AFPs could pave the way for novel antifungal agents with broad-spectrum activity, reduced toxicity, targeted action, and mechanisms that limit resistance in pathogenic fungi, offering significant advancements in antifungal therapeutics.

Antifungal Peptides as Therapeutic Agents

Fungi have been used since ancient times in food and beverage-making processes and, more recently, have been harnessed for the production of antibiotics and in processes of relevance to the bioeconomy. Moreover, they are starting to gain attention as a key component of the human microbiome. However, fungi are also responsible for human infections. The incidence of community-acquired and nosocomial fungal infections has increased considerably in recent decades. Antibiotic resistance development, the increasing number of immunodeficiency- and/or immunosuppression-related diseases and limited therapeutic options available are triggering the search for novel alternatives. These new antifungals should be less toxic for the host, with targeted or broader antimicrobial spectra (for diseases of known and unknown etiology, respectively) and modes of actions that limit the potential for the emergence of resistance among pathogenic fungi. Given these criteria, antimicrobial peptides with antifungal properties, i.e., antifungal peptides (AFPs), have emerged as powerful candidates due to their efficacy and high selectivity. In this review, we provide an overview of the bioactivity and classification of AFPs (natural and synthetic) as well as their mode of action and advantages over current antifungal drugs. Additionally, natural, heterologous and synthetic production of AFPs with a view to greater levels of exploitation is discussed. Finally, we evaluate the current and potential applications of these peptides, along with the future challenges relating to antifungal treatments.

Evaluation of therapeutic potential of recombinant buffalo lactoferrin N-lobe expressed in E. coli

Lactoferrin (Lf) is a multifunctional bi-lobate iron-binding glycoprotein belonging to transferrin family with a mass of approximately 80 kD. Being ubiquitously present in almost all biological secretions, it performs important biological functions. One of the earliest and very well-documented functions of Lf is the antibacterial effect against broad spectrum Gram-negative and Gram-positive bacteria. In this study, buffalo Lf N-lobe cDNA was amplified, cloned and expressed as a fusion protein in Escherichia coli cells using pQE30 expression vector. After post-induction confirmation of expressed protein by SDS-PAGE, purification of recombinant protein using Ni-NTA was attempted and the yield of recombinant buffalo N-lobe Lf was estimated to be 1 mg/ml. Antibacterial activity of recombinant buffalo Lf N-lobe was assessed on pathogenic E. coli and Staphylococcus aureus strains. Peptic digest of recombinant N-lobe buffalo Lf showed antibacterial activity comparable to commercially available bovine Lf. The successful expression and characterization of functional recombinant N-lobe of buffalo Lf expressed in E. coli opens new vistas for developing alternate therapeutics, particularly against the diseases caused by Gram-negative microbes such as septicemia and diarrhea in newborn calves and mastitis in dairy animals.

Lactoferrin as a natural regimen for selective decontamination of the digestive tract: recombinant porcine lactoferrin expressed in the milk of transgenic mice protects neonates from pathogenic challenge in the gastrointestinal tract

BACKGROUND

Nosocomial infection with antibiotic-resistant strains is a major threat to critical care medicine. Selective decontamination of the digestive tract (SDD) is one of the strategies used to reduce ventilator-associated pneumonia and sepsis in critically ill patients. In the present study, we performed pathogenic challenges of the digestive tract in a transgenic milk-fed animal model to test whether porcine lactoferrin (pLF) is an effective SDD regimen.

METHODS

Transgenic mice expressing recombinant pLF in their milk at a mean+/-SD concentration of 120+/-13.6 mg/L during the lactation stage fed normal CD-1 mice pups for 4 weeks. The pups were subsequently challenged with pathogenic Escherichia coli, Staphylococcus aureus, and Candida albicans.

RESULTS

Compared with the control groups fed wild-type (normal) milk, the groups fed pLF-enriched milk demonstrated statistically significant improvements in weight gain; lower bacterial numbers in intestinal fluid, blood, and liver; healthier microvilli in the small intestine; and alveoli in the lungs.

CONCLUSIONS

Our results showed that oral administration of pLF-enriched milk to mice led to broad-spectrum antimicrobial activity in the digestive tract and protected the mucosa of the small intestine from injury, implying that pLF can be used as an effective SDD regimen.

On the evolutionary significance and metal-binding characteristics of a monolobal transferrin from Ciona intestinalis

Transferrins are a family of proteins that bind and transport Fe(III). Modern transferrins are typically bilobal and are believed to have evolved from an ancient gene duplication of a monolobal form. A novel monolobal transferrin, nicatransferrin (nicaTf), was identified in the primitive ascidian species Ciona intestinalis that possesses the characteristic features of the proposed ancestral Tf protein. In this work, nicaTf was expressed in Pichia pastoris. Extensive solution studies were performed on nicaTf, including UV-vis, fluorescence, CD, EPR and NMR spectroscopies, and electrospray time-of-flight mass spectrometry. The expressed protein is nonglycosylated, unlike the protein isolated from the organism. This property does not affect its ability to bind Fe(III). However, Fe(III)-bound nicaTf displays important spectral differences from other Fe(III)-bound transferrins, which are likely the consequence of differences in metal coordination. Coordination differences could also account for the weaker affinity of nicaTf for Fe(III) (log K = 18.5) compared with bilobal human serum transferrin (HsTf) (log K = 22.5 and 21.4). The Fe-nicaTf complex is not labile, as indicated by slow metal removal kinetics by the high-affinity chelator tiron at pH 7.4. The protein alternatively binds up to one equivalent of Ti(IV) or V(V), which suggests that it may transport nonferric metals. These solution studies provide insight into the structure and function of the primitive monolobal transferrin of C. intestinalis for comparison with higher order bilobal transferrins. They suggest that a major advantage for the evolution of modern transferrins, dominantly of bilobal form, is stronger Fe(III) affinity because of cooperativity.

On the role of breastfeeding in health promotion and the prevention of allergic diseases

Based on animal models, we specify the major role of different bioactive milk components known to participate significantly in neonatal health promotion and in protection against a large number of infectious diseases and the development of allergies and asthma.