Gram-negative bacteria and their lipopolysaccharides in Alzheimer’s disease: pathologic roles and therapeutic implications

Table 3 Gram-negative bacteria-derived products affect Alzheimer’s disease and other diseases

	Gram-negative bacteria-derived products	AD-related pathology					References
	Gram-negative bacteria-derived products	Aβ	Tau	Neuroinflammation	Cell death	BBB disruption	References
In Alzheimer’s disease	Gingipain	Production ↑	Hyperphosphorylation ↑ Aggregation ↑	Proinflammatory cytokines ↑	Pyroptosis ↑ Caspase-1 ↑		[59]
	Methylglyoxal (MG)	Production ↑	Hyperphosphorylation ↑		Oxidative stress↑ Apoptosis↑		[64, 85, 89]
	Hcp1					Endothelial cell disruption ↑	[55]
	Bacterial amyloid	Aggregation ↑					[82]
In other diseases	VacA			Proinflammatory cytokines ↑	Cell vacuolation ↑		[90, 91]
	Bacterial amino-acid			Systemic inflammation ↑			[10]
	Hcp1					Endothelial cell disruption ↑	[55]
	MMP8					Junctional protein degradation ↑	[92]
	Phosphorylcholine			Proinflammatory cytokine ↑			[93]
	Short chain fatty acid			Proinflammatory cytokine ↑ Gliosis ↑		Endothelial cell disruption ↑	[94,95,96]
	Tryptophan			Proinflammatory cytokine ↑ Gliosis ↑		Endothelial cell disruption ↑	[97]

AD Alzheimer’s disease, Aβ Amyloid-β, BBB blood–brain barrier, Hcp1 Heme carrier protein 1, MMP8 matrix meralloproteinase-8, ROS reactive oxygen species, VacA vacuolating cytotoxin

ISSN: 2047-9158