Preserved Expression of Skin Neurotrophic Factors in Advanced Diabetic Neuropathy Does Not Lead to Neural Regeneration despite Pancreas and Kidney Transplantation

Table 2

List of examined neurotrophic factors and their receptors.

Abbrev.	Name	NCBI reference sequence	Potential role in nerve regeneration	Reference
BDNF	Brain-derived neurotrophic factor	NM_001709	Promotion of nerve cell growth and maturation	[14]
CNTF	Ciliary neurotrophic factor	NG_008776.1	Expressed in myelinating Schwann cells, nerve regeneration following injury	[10]
CNTFR	Ciliary neurotrophic factor receptor	NG_047044.1		[10, 15]
GALR1	Galanin receptor 1	NG_009223.1	Neuroprotection, neuroregeneration
GALR2	Galanin receptor 2		Neuroprotection, neuroregeneration; Expressed in Schwann cells, ensures the response to GDNF	[15, 16] (2002)
GFRA1	GDNF family receptor alpha 1	NG_050620.1
GFRA2	GDNF family receptor alpha 2	NG_029215.1	Expressed in Schwann cells, ensures the response to GDNF; Essential role in neuronal regeneration	[16–18, 19]
GFRA3	GDNF family receptor alpha 3	NG_046894.1
NGF	Nerve growth factor	NG_007944.1
NGFR	Nerve growth factor receptor	NC_000017.11	Essential role in neuronal regeneration	[19, 20]
NGFRAP	Nerve growth factor receptor associated protein 1	NM_0012826741	Essential role in neuronal regeneration	[19]
NRG1	Neuregulin 1	NG_012005.1	Family of gliotrophic factors that transduce signal through ErbB receptors and are necessary for Schwann cells growth, survival, and differentiation	[21]
NRG2	Neuregulin 2	NC_000005.10	Family of gliotrophic factors that transduce signal through ErbB receptors and are necessary for Schwann cells growth, survival, and differentiation; Increase of NT-3 appears to reflect the degree of skin denervation in diabetic neuropathy and may represent a compensatory mechanism	[10, 21]
NRG4	Neuregulin 4	NC_000015.10
NTF3	Neurotrophin 3	NG_050629.1
NTF4	Neurotrophin 4	NG_016289.1	Increase of NT-3 appears to reflect the degree of skin denervation in diabetic neuropathy and may represent a compensatory mechanism; Essential role in neuronal regeneration	[10, 21, 22]
NTRK1	Neurotrophic receptor tyrosine kinase 1	NG_007493.1
NTRK2	Neurotrophic receptor tyrosine kinase 2	NG_012201.2	Essential role in neuronal regeneration	[21, 22]
TGFA	Transforming growth factor alpha	NG_029975.1	Trophic factor in both central and peripheral neural tissues	[23]
NPY	Neuropeptide Y	NG_016148.1	Increased expression in patients with moderate sensory neuropathy	[24]
NPY1R	Neuropeptide Y receptor Y1	NC_000004.12	Potentially involved in neuronal precursor proliferation
MPZ	Myelin protein zero	NG_008055.1	Myelin-specific protein, Schwann cells can modulate this gene expression in response to diabetic-induced metabolic derangement	[25]
GFAP	Glial fibrillary acidic protein	NG_008401.1	Glial cell marker	[26]
FGF2	Fibroblast growth factor 2	NG_029067.1	Expressed by the Schwann cells of the peripheral nerves	[27]
FGFR1	Fibroblast growth factor receptor 1	NG_007729.1	Secreted by Schwann cells, essential for neuroregeneration	[16, 27, 28]
GDNF	Glial cell-derived neurotrophic factor	NG_011675.2	Rapidly responses to denervation produced by basal keratinocytes and Schwann cells
ERBB2	erb-b2 receptor tyrosine kinase 2	NG_007503.1	Neuregulin receptors, response to chronic denervation, expressed in Schwann cells (26 hoke)	[21, 29]
ERBB3	erb-b2 receptor tyrosine kinase 3	NG_011529.1	Neuregulin receptors, response to chronic denervation, expressed in Schwann cells	[21, 29]
ERBB4	erb-b2 receptor tyrosine kinase 4	NG_011805.1