The gut microbiota metabolite butyrate mitigates MPTP/MPP+ -induced Parkinson's disease by inhibiting the JAK2/STAT3 signaling pathway

Abstract

Butyrate (BU), a gut microbiota-derived metabolite, has been reported to play a neuroprotective role in Parkinson's disease (PD). However, the specific molecular mechanism of BU has not been fully interpreted. This work aimed to verify the protective effects of BU against MPTP/MPP⁺ -induced neurotoxicity and explore the mechanisms involved. The results showed that BU protected against MPTP-induced motor dysfunction and decreased tyrosine hydroxylase (TH) and dopamine transporter (DAT) levels. Additionally, BU pretreatment improved PC12 cell viability and reduced MPP⁺ -induced PC12 cell apoptosis. BU treatment also attenuated MPP⁺ -stimulated oxidative stress and inflammatory response in PC12 cells. Furthermore, BU inhibited MPTP/MPP⁺ -induced hyperactivation of the JAK2/STAT3 signaling in mice and PC12 cells. Besides, a JAK2 agonist, Coumermycin A1 (C-A1), substantially reversed BU-mediated inhibition on JAK2/STAT3 phosphorylation in MPP⁺ -challenged PC12 cells and abated BU-induced repression on MPP⁺ -triggered apoptosis, oxidative stress, and inflammatory response in PC12 cells. To sum up, BU might exert neuroprotective effects against MPP⁺ /MPTP-induced neurotoxicity by inactivating the JAK2/STAT3 signaling.

Keywords: JAK2/STAT3; Parkinson's disease; butyrate; gut microbiota metabolite.

FIGURE 1

BU relieves MPTP‐triggered motor dysfunction and dopaminergic neuronal death in mice. Mice were divided into Sham (n = 10), MPTP (n = 10), MPTP+BU (200 mg/kg; n = 10), and MPTP+BU (600 mg/kg; n = 10) groups. (A) Pole test performance. (B) Rotarod test performance. (C and D) Western blotting for TH and DAT protein levels in the striatum. *p < 0.05; **p < 0.01; ***p < 0.001.

FIGURE 2

BU mitigates MPP⁺‐induced apoptosis. PC12 cells were assigned into Control, MPP⁺, MPP⁺+BU (0.1 μM), MPP⁺+BU (1 μM), and MPP⁺+BU (10 μM) groups. (A) CCK‐8 assay for PC12 cell viability. (B) Flow cytometry for PC12 cell apoptosis. (C) Western blotting for Bax and Bcl‐2 protein levels. *p < 0.05; **p < 0.01; ***p < 0.001.

FIGURE 3

BU alleviates MPP⁺‐stimulated oxidative stress and inflammatory responses in PC12 cells. PC12 cells were assigned into Control, MPP⁺, MPP⁺+BU (0.1 μM), MPP⁺+BU (1 μM), and MPP⁺+BU (10 μM) groups. (A–D) ROS, SOD, GSH, and MDA levels. (E–G) TNF‐α, IL‐1β, and IL‐6 levels. *p < 0.05; **p < 0.01; ***p < 0.001.

FIGURE 4

BU inhibits MPTP/MPP⁺‐induced activation of JAK2/STAT3 signaling pathway. (A) p‐JAK2, JAK2, p‐STAT3, and STAT3 protein levels in brain tissues from Sham, MPTP, MPTP+BU (200 mg/kg), and MPTP+BU (600 mg/kg) groups (B) p‐JAK2, JAK2, p‐STAT3, and STAT3 protein levels in PC12 cells from Control, MPP⁺, MPP⁺+BU (0.1 μM), MPP⁺+BU (1 μM), and MPP⁺+BU (10 μM) groups. *p < 0.05; **p < 0.01; ***p < 0.001.

FIGURE 5

JAK2/STAT3 activation reverses BU‐mediated neuroprotective effects on MPP⁺‐challenged PC12 cells. PC12 cells were assigned into Control, MPP⁺, MPP⁺+BU (10 μM), and MPP⁺+BU (10 μM) + C‐A1 groups. (A) p‐JAK2, JAK2, p‐STAT3, and STAT3 protein levels. (B) PC12 cell viability. (C) PC12 cell apoptosis. (D) Bax and Bcl‐2 protein levels. (E–H) ROS, SOD, GSH, and MDA levels. (I–K) TNF‐α, IL‐1β, and IL‐6 levels. *p < 0.05; **p < 0.01; ***p < 0.001.