Table 1:

Tissue specific expression and physiological/cellular function of FFA4.

Tissue	Cell type or cell line	Physiological or cellular function	Reference
Intestinal	L-cells	Secretion of GLP-1	[6]
	L-cells	Inhibition of GLP-2 secretion	[20]
	K-cells	Secretion of GIP	[7], [25, 27]
	Murine STC1, GLUTag	Secretion of GLP-1	[26]
	HCT116, HT-29, Caco-2 human colon epithelial cancer cells	Increase cytosolic Ca+2 Increase phosphorylation of ERK1/2	[31]
Gastric	Ghrelin secreting	Inhibition of ghrelin secretion	[33–35]
Tongue	Circumvallate papillae epithelia	Fat sensing, GLP-1 secretion	[40–42]
	Type II taste cells	Taste perception	[40–42]
Adipose	SQ, PR, Mes, Epi fat 3T3-L1 cells	Adipocyte differentiation, GLUT4 translocation, glucose uptake VEGF-A induced angiogenesis	[45–47], [52]
	M2 and M1 macrophages,	Anti-inflammatory effects, insulin sensitization	[49–51]
Macrophages	M2 and M1 macrophages, murine Raw264.7 cells, human THP-1 cells	Anti-inflammatory effects, reduced inflammasome assembly and activity, insulin sensitization	[49], [53–55]
Pancreatic Islets	Islet cells	Protection from lipotoxicity	[56]
	Human and mouse α-cells	Glucagon synthesis and secretion Downstream hepatic glucagon sensitivity	[18], [57]
	Mouse delta-cells	Inhibition of somatostatin secretion	[18]
	Murine αTC1–6 cells		[58]
Skeletal Muscle	Rat and murine gastrocnemius and soleus skeletal muscle	Reduced inflammation, improved insulin sensitivity	[51], [59]
	Rat L6 and murine C2C12 myoblasts	GLUT4 translocation and increased glucose uptake	[60]
Liver	Murine macrophage-like Kupffer cells	Reduced inflammation	[62]
	Human hepatocytes, hepatic stem/progenitor cells, and hepatic Kupffer cells	Reduced inflammation, macrophage polarization	[63]
	Rat liver WB-F344 cells	Cell migration	[66]
Bone	Osteoclasts	Reduced inflammation, inhibition of osteoclast development and bone resorption	[70–72]
	Murine ST2 and MC3T3-E1 preosteoblasts		[70]