Correlation of the Structure and Bioactivity of Recombinant Fungal Immunomodulatory Protein, Ling-Zhi-8 (LZ-8) Following Exposure to Denaturing Conditions

Quantitative detection of Ganodermati lucidum immunomodulatory protein-8 by a peptide-antigen-antibody sandwich ELISA

In order to rapidly determine the concentration of recombinant Ganoderma lucidum immunomodulatory protein-8 (rLZ-8) at a lower cost, a peptide-antigen-antibody sandwich ELISA method was developed based on a dodecapeptide LTPHKHHKHLHA with higher affinity for rLZ-8, which was identified from phage display after four rounds of screening. The binding mode between rLZ-8 and the peptide ligand was further simulated and revealed by molecular docking. Standard addition and repetitive testing were carried out to evaluate the accuracy, reproducibility and feasibility of the developed ELISA detection method. The method based on this peptide ligand was then successfully applied in the quantitative determination of rLZ-8 concentrations in fermentation broth. In summary, the peptide-antigen-antibody sandwich ELISA method developed here could be conveniently applied in the detection of rLZ-8 during fermentation and might provide new insights for the detection of other specific proteins.

PLGA nanoparticles containing Lingzhi extracts rescue corneal epithelial cells from oxidative damage

Oxidative stress-related ocular surface epithelial damage can be initiated by ambient oxygen, UV radiation, and chemical burns. The oxidative damage to cornea can lead to inflammation and even vision loss. Lingzhi (Ganoderma lucidum) is a Chinese herbal drug and has been shown to prevent chronic diseases in clinical practices and has been proven to possess anti-oxidative and anti-inflammatory properties. In the study, we prepared poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) as a sustained drug release system of Lingzhi (LZH) to improve bioavailability. The particle size of developed NPs containing LZH (LZH-NPs) was ~184 nm with narrow size distribution. The results of cellular uptake revealed that using NPs as a drug delivery system could significantly increases the intracellular retention time. The results of the cell viability and chemiluminescence assay revealed that 5 μg/ml of LZH-NPs might be the threshold concentration for cultivation of corneal epithelial cells. After treating LZH-NPs in oxidative damaged cells, the results showed that the inflammation-related gene expression and DNA fragmentation level were both significantly decreased. Post-treatment of LZH-NPs in damaged corneal epithelial cells could increase the cell survival rate. In the rabbit corneal alkali burn model, topical instillation of LZH-NPs could promote corneal wound healing and decrease the inflammation. These results suggest that LZH-NPs may have the potential to treat ocular surface diseases caused by oxidative stress.

Current Understanding of the Structure and Function of Fungal Immunomodulatory Proteins

Fungal immunomodulatory proteins (FIPs) are a group of proteins found in fungi, which are extensively studied for their immunomodulatory activity. Currently, more than 38 types of FIPs have been described. Based on their conserved structure and protein identity, FIPs can be classified into five subgroups: Fve-type FIPs (Pfam PF09259), Cerato-type FIPs (Pfam PF07249), PCP-like FIPs, TFP-like FIPs, and unclassified FIPs. Among the five subgroups, Fve-type FIPs are the most studied for their hemagglutinating, immunomodulating, and anti-cancer properties. In general, these small proteins consist of 110–125 amino acids, with a molecular weight of ~13 kDa. The other four subgroups are relatively less studied, but also show a noticeable influence on immune cells. In this review, we summarized the protein modifications, 3-dimensional structures and bioactivities of all types of FIPs. Moreover, structure-function relationship of FIPs has been discussed, including relationship between carbohydrate binding module and hemagglutination, correlation of oligomerization and cytokine induction, relevance of glycosylation and lymphocyte activation. This summary and discussion may help gain comprehensive understanding of FIPs' working mechanisms and scope future studies.

Identification of a Novel Anti-cancer Protein, FIP-bbo, from Botryobasidium botryosum and Protein Structure Analysis using Molecular Dynamic Simulation

Fungal immunoregulatory proteins (FIP) are effective small molecule proteins with broad-spectrum immunomodulatory and anti-cancer activities and can be potential agents for the development of clinical drugs and health food additives. In this study, a new member of FIP named FIP-bbo was obtained through Botryobasidium botryosum genome mining. FIP-bbo has the typical characteristics of FIP but is genetically distant from other FIPs. Recombinant FIP-bbo (rFIP-bbo) was produced in an optimized E. coli expression system, and the pure protein was isolated using a Ni-NTA column. Antineoplastic experiments suggested that FIP-bbo is similar to LZ-8 in inhibiting various cancer cells (Hela, Spac-1, and A549) at lower concentrations, but it is not as potent as LZ-8. The molecular mechanism by which FIP-bbo, FIP-fve, and LZ-8 are cytotoxic to cancer cells has been discussed based on molecular dynamics simulation. Point mutations that may improve the thermal stability of FIP-fve and FIP-bbo were predicted. These results not only present a new candidate protein for the development of anticancer adjuvants, but also provide an approach for designing FIPs with high anticancer activity.