Ulva polysaccharide alleviates Parkinson's disease by regulating inflammation, oxidative damage, and gut microbiota

Current therapeutic options for Parkinson's disease (PD) are limited in efficacy and burdened with severe side-effects. Inflammation, intertwined with oxidative stress and influenced by gut microbiota-related changes making the gut-brain axis the main target of innovative therapies. This study reveals the multiple protective effects of polysaccharides extracted from Ulva lactuca (UPE) on PD models. In vitro, UPE was shown to have direct cytoprotective effects, including mitigating 1-methyl-4-phenylpyridinium-induced cell apoptosis, reducing reactive oxygen species levels, and maintaining mitochondrial membrane potential. In vivo, oral UPE significantly restored motor deficits and dopaminergic neuron loss caused by MPTP. These in vivo benefits were associated with the inhibition of oxidative stress and inflammation. Moreover, oral UPE inhibits the excessive activation of glial cells and the excessive production of pro-inflammatory factors and oxidative stress markers in serum. Furthermore, 16S rRNA analysis of gut microbiota revealed that UPE reshaped the gut microbiota of PD mice by increasing the abundance of norank_f_Murbaculaceae and decreasing the abundance of Desulfovibrio. Mechanically, the Nrf2/HO-1 and TLR4/NF-κB signaling pathways are involved in the anti-PD effect of UPE. In general, UPE offers new perspectives on PD treatment and demonstrates the potential of natural polysaccharides in treating neurodegenerative diseases.