Purification of novel polypeptides from bee pupae and their immunomodulatory activityin vivo andin vitro

Abstract

Edible insects have been proposed as an understudied food whose cultivation could be increased with global population growth. However, the bioactivators and bioactivities of bee pupae are poorly studied. In this paper, the active ingredients of bee pupa powder were analysed, and novel bee pupa polypeptides (BPP) were obtained through protein hydrolysis with alkaline protease. Two purified polypeptide components (BPP-21 and BPP-22) were isolated and purified on a diethylaminoethyl-sepharose fast flow column and a Sephadex G-25 column, and identified using size exclusion chromatography-high performance liquid chromatography and amino acid composition analyses. Due to its higher cell proliferation activity, BPP-22 was selected for further study of its immunomodulatory activity and mechanism in vivo and in vitro. The analysis of immunomodulatory activity showed that BPP-22 significantly increased the body weight growth rate, organ index, macrophage phagocytosis, delayed-type hypersensitivity reaction, cytokine level (interleukin (IL)-2 and interferon (IFN)-γ), immunoglobulin (Ig) levels (IgA, IgG, and IgM), and routine blood indexes in cyclophosphamide-treated immunosuppressed mice (P<0.01). Mechanistic research in RAW264.7 cells showed that BPP-22 might promote the secretion of cytokines (IL-2, tumour necrosis factor-α and IFN-γ) and the production of nitric oxide by increasing homologous mRNA expression and could exert immunomodulatory activity by increasing the phosphorylation of ERK and p38, and modulating the expression of intranuclear transcription factors (EIK-1, MEF-2 and CREB) in the MAPK signalling pathway. These findings are helpful for promoting the application of bee pupae as potential immunomodulatory agents and protein supplements.

Edible insects as a source of biopeptides and their role in immunonutrition

“…The cationic peptide fractions contained in the hydrolysate were able to inhibit LPS-induced inflammation in RAW 264.7 cells, although not exhibiting a dose-dependent behaviour in the range of the concentrations evaluated (0.5 to 3 µg mL −1 ). Similar to this, Chen et al 40 evaluated the potential of a bee pupa-derived peptide in RAW 264.7 cells, and according to the authors, this implied a promotion of IL-2, TNF-α and interferon gamma (IFN-γ) secretion, while also leading to the production of NO and increasing the phosphorylation of extracellular signal-regulated kinase (ERK) and p38, and modulating the expression of intranuclear transcription in the MAPK signalling pathway. In the context of the prevention of non-alcoholic fatty liver disease (NAFLD), the potential of Gryllus bimaculatus protein hydrolysates (obtained with Neutrase or Flavourzyme) in modulating hepatic lipid accumulation, inflammation, and endoplasmic reticulum stress in Hep G2 cells treated with palmitic acid was assessed.…”

“…Recently, Chen et al 40 hydrolysed bee pupae with alkaline protease and were able to purify two peptides, and one of them was used to assess its immunomodulatory activity in vivo . In this regard, cyclophosphamide-treated immunosuppressed mice were exposed to the peptide, and this led to a significant increase in body weight growth rate, organ index, macrophage phagocytosis, delayed-type hypersensitivity reaction, and cytokine levels (IL-2, IFN-γ, IgA, IgG, and IgM).…”

“…54 However, some of these studies concluded that no specific changes with biological relevance related to the consumption of insects could be defined. Table 2 summarizes the in vivo studies with animals, reporting the effect of insect protein and products thereof (not including studies with specific synthesized peptides 40,55 ) on modulation of the immune system.…”

Revisiting edible insects as sources of therapeutics and drug delivery systems for cancer therapy

“…It enhanced the production of antibodies IgA, IgE, IgM, IL-2, INF-γ and elevated the phagocytic activity of macrophages in an immunosuppressied mouse model. It is suggested that BPP-22 exerts its immunomodulatory effects by elevating the phosphorylation of ERK and p38 and modulating the MAPK signaling pathway (Chen et al, 2022).…”

“…Insect derived lectins show anti-cancer immunomodulatory activity through M1 macrophage mediated phagocytosis (Cao et al, 2012). The capacity of insect peptides to modify the immune response against cancer cells has been shown in several researches (Sun et al, 2014;Chen et al, 2022;Yang K. et al, 2023). It has been seen that, some insect peptide fragments interact with immune cells, including DC, natural killer (NK) cells, and T lymphocytes, among others, and enhance their activity.…”