Bee venom phospholipase A2 is a lipolytic enzyme in bee venom that catalyzes hydrolysis of the sn-2 ester bond of membrane phospholipids to produce free fatty acid and lysophospholipids. Current evidence suggests that bee venom phospholipase A2 (bvPLA2) induces regulatory T cell expansion and attenuates several immune system-related diseases, including Alzheimer’s disease. The induction of Treg cells is directly mediated by binding to mannose receptors on dendritic cells. This interaction induces the PGE2-EP2 signaling pathway, which promotes Treg induction in CD4⁺ T cells. In this study, we investigated the effects of bvPLA2 treatment on the apoptotic signaling pathway in Treg populations. Flow cytometry was performed to identify early apoptotic cells. As a result, early apoptotic cells were dramatically decreased in bvPLA2-treated splenocytes, whereas rapamycin-treated cells showed levels of apoptotic cells similar to those of PBS-treated cells. Furthermore, bvPLA2 treatment increased expression of anti-apoptotic molecules including CTLA-4 and PD-1. The survival rate increased in bvPLA2-treated Tregs. Our findings indicate that bvPLA2-mediated modulation of apoptotic signaling is strongly associated with the Treg induction, which exhibits protective effects against various immune-related diseases. To our knowledge, this study is the first to demonstrate that bvPLA2 is the major bee venom (BV) compound capable of inducing Treg expansion through altering apoptotic signal.

Parkinson’s disease (PD) is a long-term neurodegenerative disease characterized by dopaminergic neuronal loss and the aggregation of alpha-synuclein (α-syn) in the brain. Cell therapy using regulatory T cells (Tregs) has therapeutic potential on PD progression in a mouse model; however, several challenges were associated with its applications. Here, we propose a strategy for α-syn specific Treg expansion (α-syn Treg). We presented α-syn to T cells via dendritic cells. This method increased the mobility of Tregs towards the site of abundant α-syn in vitro (p < 0.01; α-syn Tregs versus polyclonal Tregs (poly Tregs)) and in vivo. Consequently, α-syn Tregs showed noteworthy neuroprotective effects against motor function deficits (p < 0.05, p < 0.01; α-syn Tregs versus poly Tregs), dopaminergic neuronal loss (p < 0.001; α-syn Tregs versus poly Tregs), and α-syn accumulation (p < 0.05; α-syn Tregs versus poly Tregs) in MPTP-induced PD mice. Furthermore, the adoptive transfer of α-syn Tregs exerted immunosuppressive effects on activated microglia, especially pro-inflammatory microglia, in PD mice. Our findings suggest that α-syn presentation may provide a significant improvement in neuroprotective activities of Tregs and suggest the effective clinical application of Treg therapy in PD.

The aging global population is placing an increasing burden on healthcare systems, and the social impact of Alzheimer’s disease (AD) is on the rise. However, the availability of safe and effective treatments for AD remains limited. Adoptive Treg therapy has been explored for treating neurodegenerative diseases, including AD. To facilitate the clinical application of Treg therapy, we developed a Treg preparation protocol and highlighted the therapeutic effects of Tregs in 5xFAD mice. CD4⁺CD25⁺ Tregs, isolated after Aβ stimulation and expanded using a G-rex plate with a gas-permeable membrane, were adoptively transferred into 5xFAD mice. Behavioral analysis was conducted using Y-maze and passive avoidance tests. Additionally, we measured levels of Aβ, phosphorylated tau (pTAU), and nitric oxide synthase 2 (NOS2) in the hippocampus. Real-time RT-PCR was employed to assess the mRNA levels of pro- and anti-inflammatory markers. Our findings indicate that Aβ-specific Tregs not only improved cognitive function but also reduced Aβ and pTAU accumulation in the hippocampus of 5xFAD mice. They also inhibited microglial neuroinflammation. These effects were observed at doses as low as 1.5 × 10³ cells/head. Collectively, our results demonstrate that Aβ-specific Tregs can mitigate AD pathology in 5xFAD mice.

CX3CR1-transduced regulatory T cells (Tregs) have shown potential in reducing neuroinflammation by targeting microglial activation. Reactive microglia are implicated in neurological disorders, and CX3CR1-CX3CL1 signaling modulates microglial activity. The ability of CX3CR1-transduced Tregs to inhibit LPS-induced neuroinflammation was assessed in animal models. CX3CR1 Tregs were administered to LPS-induced and 3xTg Alzheimer’s mouse models, resulting in reduced proinflammatory marker expression in both the cortices and hippocampi. In the 3xTg Alzheimer’s model, neuroinflammation was significantly reduced, demonstrating the efficacy of CX3CR1 Tregs even in chronic neuroinflammatory conditions. These findings highlight the therapeutic potential of CX3CR1 Treg therapy in modulating microglial activity and offer promising treatment strategies for neurodegenerative diseases.

Background: Fine dust penetrates deep into the human alveoli, and the fine dust accumulated in the bronchus and lungs can directly trigger various respiratory diseases. PM014 (HL301) is the herbal extract derived from the herbal medicine Chung-Sang-Bo-Ha-Tang which is used for the treatment of lung diseases. Methods: To evaluate the effect of PM014 on the lung inflammation induced by fine dust, this study investigated inflammatory responses in the lung upon pm10 exposure by examining the infiltration of inflammatory cell profiles from bronchial alveolar lavage fluid (BALF), lung histology, and production of pro-inflammatory cytokines measured by RT-PCR and ELISA. Results: PM014-treated mice exhibited reduced lung tissue damage and inflammatory cell infiltration. Bronchoalveolar lavage fluid (BALF) analysis showed significant decrease in the population of total cells, macrophages, eosinophils, and neutrophils in PM014-treated mice. PM014 treatment downregulated the pro-inflammatory cytokine expressions including IL-1b, IL-8, IL-6, TNF-alpha, IL-21 and IL-17. ELISA analysis also showed reduced production of IL-1b, IL-6 and IL-17 in PM014-treated mice. Conclusion: PM014 suppressed the pm10-induced inflammatory response in mice. This study shows that PM014 is a possible therapeutic agent for lung inflammation induced by fine dust.

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.