Table 2.

Summary of novel targets of age-related skeletal muscle atrophy (2009-2019)

Classification	Molecular Targets	Atrophy-related Mediated Targets	Age-related Atrophy Year Identification	Reference(s)
Proteostasis	TSC	Fox03, mTORC1	2014	[39]
	dkk3	Fox03-p-catenin, WNT signaling	2018	[56]
	ATF4	4E-BP1?	2015	[46]
	FGF21	FoxOs	2017	[57]
	p110α PI3K	mTORCl	2019	[43]
Immune System	TWEAK-Fn14	NF-κB	2014	[79]
	IL-15	NF-κB, IL-15Ra, TNF-R1	2009	[81]
	IL-10*	Unknown	2016	[181]
Denervation-Induced Atrophy	Sarcoglycan α	LRP4, MuSK	2018	[96]
	LRP4	MuSK	2014	[93]
	Agrin	LRP4	2012	[94]
Redox Homeostasis	GPx7	OGA	2019	[122]

^*denotes target with no evidence from muscle weight data.

Abbreviations: ATF4, activating transcription factor 4; dkk3, dickkopf 3; FoxO, forkhead family of transcription factors; FGF21, fibroblast growth factor 21; GPx7, non-selenocysteine-containing phospholipid hydroperoxide glutathione peroxidase; IL, interleukin; mTORC1, mammalian target of rapamycin complex 1; LRP4, low-density lipoprotein receptor-related protein 4; MuSK, muscle-specific kinase; NF-κB, necrosis factor kappa-light-chain-enhancer of activated B cells; OGA, o-GlcNAcylation; TNF-R1, tumor necrosis factor receptor 1; TWEAK, TNF-related weak inducer of apoptosis; WNT, wingless-INT.