Lin, Y.-E. | bioRxiv Science

bioRxiv2021

Gastrodia elata Blume prevents dopaminergic neuron degeneration via glial Nrf2 signaling in Lrrk2-G2019S Parkinson's disease models

The most frequent missense mutations in familial Parkinsons disease (PD) occur in the highly conserved LRRK2/PARK8 gene with G2019S mutation. We previously established a fly model of PD carrying the LRRK2-G2019S mutation that exhibited the parkinsonism-like phenotypes. An herbal medicine--Gastrodia elata Blume (GE), has been reported to have neuroprotective effects in toxin- induced PD models. However, the underpinning molecular mechanisms of GE beneficiary to G2019S- induced PD remain unclear. Here, we show that these G2019S flies treated with water extracts of GE (WGE) and its bioactive compounds, gastrodin and 4-HBA, displayed locomotion improvement and dopaminergic neuron protection. WGE suppressed the accumulation and hyperactivation of G2019S proteins in dopaminergic neurons, and activated the antioxidation and detoxification factor Nrf2 mostly in the astrocyte-like and ensheathing glia. Glial activation of Nrf2 antagonizes G2019S-induced Mad/Smad signaling. Moreover, we treated LRRK2-G2019S transgenic mice with WGE and found the locomotion declines, the loss of dopaminergic neurons, and the number of hyperactive microglia were restored. WGE also suppressed the hyperactivation of G2019S proteins and regulated the Smad2/3 pathways in the mice brains. We conclude that WGE prevents locomotion defects and the neuronal loss induced by G2019S mutation via glial Nrf2/Mad signaling, unveiling a potential therapeutic avenue for PD.

neuroscience↗

bioRxiv2021

Dietary Exposure to Antibiotic Residues Facilitates Metabolic Disorder by Altering the Gut Microbiota and Bile Acid Composition

Antibiotics used as growth promoters in livestock and animal husbandry can be detected in animal-derived food. Epidemiological studies have implicated that exposure to these antibiotic residues in food may be associated to childhood obesity. Herein, the effect of exposure to residual dose of tylosin--an antibiotic growth promoter--on host metabolism and gut microbiota was explored in vivo. Theoretical maximal daily intake (TMDI) doses of tylosin were found to facilitate high-fat diet-induced obesity, induce insulin resistance, and perturb the composition of gut microbiota in mice. The obesity-related phenotypes were transferrable to germ-free recipient mice, indicating that the effects of TMDI dose of tylosin on obesity and insulin resistance occurred mainly via alteration of the gut microbiota. Tylosin TMDI exposure restricted to early life, which is the critical period of gut microbiota development, altered the abundance of specific bacteria related to host metabolic homeostasis later in life. Moreover, early-life exposure to tylosin TMDI was sufficient to modify the ratio of primary to secondary bile acids, thereby inducing lasting metabolic consequences via the downstream FGF15 signaling pathway. Altogether, these findings demonstrate that exposure to very low dose of antibiotic residues, whether continuously or in early life, can exert long-lasting effects on host metabolism by altering gut microbiota and its metabolites. ImportanceEvidence has indicated that chronic exposure to antibiotic residues in food could contribute to obesity. However, few studies have investigated the effect of chronic exposure to very low-dose antibiotic residue in food (~1000-fold lower than the therapeutic dose) on gut microbiota and host metabolism. Our study demonstrates that even with limited exposure in early life, a residual dose of tylosin causes lasting metabolic disturbances through altering gut microbiota and its metabolites. Our findings reveal that the gut microbiota is susceptible to previously ignored environmental factors.

microbiology↗