Oral administration of Pantoea agglomerans-derived lipopolysaccharide prevents metabolic dysfunction and Alzheimer's disease-related memory loss in senescence-accelerated prone 8 (SAMP8) mice fed a high-fat diet.

ABSTRACT: The pathogenesis of Alzheimer's disease (AD) remains unclear, but an imbalance between the production and clearance of amyloid-? (A?) peptides is known to play a critical role in AD progression. A promising preventative approach is to enhance the normal A? clearance activity of brain phagocytes such as microglia. In mice, the intraperitoneal injection of Toll-like receptor 4 agonist was shown to enhance A? clearance and exhibit a preventative effect on AD-related pathology. Our previous clinical study demonstrated that orally administered Pantoea agglomerans-derived lipopolysaccharide (LPSp) exhibited an LDL (low-density lipoprotein)-lowering effect in human volunteers with hyperlipidemia, a known risk factor for AD. In vitro studies have shown that LPSp treatment increases A? phagocytosis by microglial cells; however it is still unclear whether orally administered LPSp exhibits a preventive effect on AD progression. We show here that in senescence-accelerated prone 8 (SAMP8) mice fed a high-fat diet, oral administration of LPSp at 0.3 or 1 mg/kg body weight·day for 18 weeks significantly improved glucose metabolism and lipid profiles. The LPSp treatment also reduced pro-inflammatory cytokine expression and oxidative-burst activity in the peripheral blood. Moreover, LPSp significantly reduced brain A? burden and memory impairment as seen in the water maze test, although we could not confirm a significant enhancement of A? phagocytosis in microglia isolated from the brains after treatment. Taken together, our results show that LPSp holds promise as a preventative therapy for AD or AD-related diseases induced by impairment of metabolic functions.

SUBMITTER: Kobayashi Y 

PROVIDER: S-EPMC5983504 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature