The Responsiveness of Bee Venom Phospholipase A2 on Regulatory T Cells Correlates with the CD11c+CD206+Population in Human Peripheral Blood Mononuclear Cells

Bee venom phospholipase A2 (bvPLA2) has been reported to have therapeutic effects such as neuroprotection, anti-inflammation, anti-nociception, anti-cancer properties, caused by increasing regulatory T cells (Tregs). The mechanism of Tregs modulation by bvPLA2 has been demonstrated by binding with the mannose receptor, CD206 in experimental models of several diseases. However, it remains unknown whether this mechanism can also be applied in human blood. In this study, we collected peripheral blood samples from healthy donors and analyzed the percentages of monocyte-derived dendritic cells with CD206 (CD206⁺ DCs) before expansion, the proportion of Tregs, and the subpopulations after expansion treated with bvPLA2 or PBS using flow cytometry and the correlations among them. The percentage of Tregs tended to be higher in the bvPLA2 group than in the control group. There were significant positive correlations between the CD206 population in hPBMC and the proportions of Tregs treated with bvPLA2, especially in the Treg fold change comparing the increase ratio of Tregs in bvPLA2 and in PBS. These findings indicate that bvPLA2 increased the proportion of Tregs in healthy human peripheral blood and the number of CD206⁺ DCs could be a predictor of the bvPLA2 response of different individuals.

Comparison of Administration Routes on the Protective Effects of Bee Venom Phospholipase A2 in a Mouse Model of Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide. Progressive loss of dopaminergic neurons in the substantia nigra (SN) and their synaptic terminal connections in the striatum are main characterizations of PD. Although many efforts have been made to develop therapeutics, no treatment has been proven effective. We previously demonstrated that bvPLA2 can protect dopaminergic neurons by modulating neuroinflammatory responses in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD. The cellular basis for the neuroprotective response of bvPLA2 was the induction of CD4⁺CD25⁺ regulatory T cells (Tregs), a population known to suppress immune activation and maintain homeostasis and tolerance to self-antigen. The aim of the present study was to investigate the effects of different routes of bvPLA2 administration in a PD mouse model. Neurobehavioral assessment revealed progressive deterioration in locomotor functions of the MPTP group compared with the control group. However, such functions were improved following subcutaneous (s.c.) bvPLA2 administration. The results showed that the s.c. route of bvPLA2 administration contributed to the induction of Treg cells and the reduction of Th1 and Th17 populations, demonstrating that the neuroprotective effects were associated with reduced tyrosine hydroxylase (TH)-positive dopaminergic neurons and microglia. These results suggested that the s.c. bvPLA2 injection could be beneficial for treating aspects of PD.

Bee Venom Phospholipase A2 Alleviate House Dust Mite-Induced Atopic Dermatitis-Like Skin Lesions by the CD206 Mannose Receptor

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by highly pruritic, erythematous, and eczematous skin plaques. We previously reported that phospholipase A2 (PLA2) derived from bee venom alleviates AD-like skin lesions induced by 2,4-dinitrochlorobenzene (DNCB) and house dust mite extract (Dermatophagoides farinae extract, DFE) in a murine model. However, the underlying mechanisms of PLA2 action in actopic dermatitis remain unclear. In this study, we showed that PLA2 treatment inhibited epidermal thickness, serum immunoglobulin E (IgE) and cytokine levels, macrophage and mast cell infiltration in the ear of an AD model induced by DFE and DNCB. In contrast, these effects were abrogated in CD206 mannose receptor-deficient mice exposed to DFE and DNCB in the ear. These data suggest that bvPLA2 alleviates atopic skin inflammation via interaction with CD206.