Table 2.

Cell types that can be converted to induced neurons.

Source Cells	Species	Transcription Factors	Media Additives	Induced cells	Efficiency (%)	Time (days)	Ref.
Astrocyte	Mouse	Neurog2; Ascl1 and/or Dlx2	B27, BDNF, 10% CO2, no change medium	Glutamatergic neurons; GABAergic neurons	85.4; 33.7	26; 22	[36], [37]
Astrocyte; NG2 cells	Mouse; Human	NeuroD1	In vivo; EGF, FGF2	Glutamatergic neurons; Glutamatergic & GABAergic neurons	In vivo; human 90	7	[38]
Astrocyte	Mouse (adult)	Sox2	In vivo, BDNF, Noggin, histone deacetylase inhibitor	Neuroblasts (iANBs)	In vivo N/A	21	[41]
Astrocyte	Mouse	Brn4	None	Neuron	2.5–3.5	20	[40]
Astrocyte	Mouse	Ascl1	In vivo	Neuron	76.8± 6.4	10–21	[39]
Astrocyte	Mouse	Sox2	In vivo, valproic acid	Neuroblasts neuron	6–7	4 weeks	[42]
Astrocyte	Rat	None	Defined medium: 5C	Tuj+ neuronal like cells	22–40	16	[64]
Astrocyte	Mouse	None	VPA, CHIR99021, Repsox	Neuronal cells	20–30	12–18	[65]
Glioma	Rat	None	Taxol	Neuron, astrocyte, oligodendrocytes	20	48 h	[66]
NG2 glia	Mouse	Sox2	In vivo	Neuron	13.9 ± 3.5	12	[43]
NG2 glia	Mouse	Ascl1, Lmx1a, Nurr1	In vivo	Neuron	20.8 ±5.9; 6.8 ±2.9	4–12 weeks	[44]
Muller glia cells	Mouse	P53 (RNAi)	None	Retinal neuronal cell	80	5–10	[45]
Germ cell	C.	LIN-53 RNAi, other TFs	In vivo	Neuron	60 of 200 (30%)	6 hrs	[59]
	elegans
Hepatocyte	Mouse	Ascl1, Brn2, Myt1l	N3 medium	Neuron	Postnatal: 6; Adult: 2.7	13	[46]
Cochlear non-sensory epithelial cells	Mouse	Ascl1/ NeuroD1	None	Neurons	43±7; 91±2	7	[48]
CD133+ cord blood cells	Human	Sox2,	None	Neuron	25–80	15–30	[49]
		c-Myc
Myoblasts	Mouse	REST-VP16	None	Neuronal phenotype	N/A	20	[55], [56]
Pericyte	Human	Ascl1, Sox2	5% O2	Neurons	48	28–35	[57], [58]
Human urine cells	Human	Ascl1, Brn2, NeuroD, c-Myc, Myt1l	None	Neurons	1.55 ±0.01	14	[62]

iANBs, induced adult neuroblasts; iNPCs, induced neural precursor cells.