TABLE 1.

Involvement of adenosine metabolism enzymes, transporters and receptors in HD.

Enzyme/transporter/receptor	Treatment	Model	Expression/activity	Effect	References
ADA		HEK 293T cells expressing HTT with 54 repeats	Increased activity		Toczek et al. (2018)
Ectonucleoside triphosphate diphosphohydrolase, CD73, ectosolic ADA		HEK 293T cells expressing HTT with 54 repeats	Decreased activity		Toczek et al. (2018)
ADA, CD39, CD73		R 6/2 mouse	No change in expression		Kao et al. (2017)
ADK		R 6/2 mouse	Increased expression		Kao et al. (2017)
ADK		Hdh150Q mouse	No change in expression		Kao et al. (2017)
AMPK		Human,Mouse striatal neurons	Increased expression		Ju et al. (2011)
AMPK	Metformin	R 6/2 mouse		Increased survival	Ma et al. (2007)
AMPK	Metformin	Immortalized striatal cells		Increased survival	Jin et al. (2016)
ENT1		zQ175, R6/2 and Hdh150Q	Increased expression		Guitart et al. (2016)
					Kao et al. (2017)
ENT1	Inhibitor, knockout	R 6/2 mouse		Increased survival, increased motor function	Kao et al. (2017)
ENT2		R6/2 and Hdh150Q mouse	Increased expression		Kao et al. (2017)
A2AR		Human, rat and mouse models	Decreased expression		Lee and Chern (2014)
A2AR		zQ175 mouse	Decreased expression		Guitart et al. (2016)
A2AR		Tg51 rat	No change in expression		Guitart et al. (2016)
A2AR	Agonist	R 6/2 mouse		Decreased motor deficits	Chou et al. (2005)
A2AR	Knockout	R 6/2 mouse		Increased cognitive function	Li et al. (2015)
AR	Caffeine (non selective antagonist)	Human		Decreased disease onset	Simonin et al. (2013)
ARAR gene polymorphisms		Human		Decreased disease onset	Dhaenens et al. (2009); Taherzadeh-Fard et al. (2010)
A1AR		Human	Decreased in symptomatic, increased in presymptomatic		Matusch et al. (2014)
A1AR	Agonist	Rat, 3-nitropropionic acid infusion		Attenuation motor deficit	Blum et al. (2002)
A1AR	Antagonist	R 6/2 mouse	Decreased binding, increased functionality		Ferrante et al. (2014)