LGALS4 and Alzheimer disease: Several Drosophila models have been established in order to clarify the underlying mechanisms for AD, including elav-Gal4;UAS-BACE/UAS-APP model, elav-Gal4;UAS-Aβ42 model and GMR-Aβ42 model, which facilitates the research on the contribution of microbiota to AD pathogenesis.