Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury

MD Zhang, G Tortoriello, B Hsueh… - Proceedings of the …, 2014 - National Acad Sciences
MD Zhang, G Tortoriello, B Hsueh, R Tomer, L Ye, N Mitsios, L Borgius, G Grant, O Kiehn…
Proceedings of the National Academy of Sciences, 2014National Acad Sciences
Neuronal calcium (Ca2+)-binding proteins 1 and 2 (NECAB1/2) are members of the
phylogenetically conserved EF-hand Ca2+-binding protein superfamily. To date, NECABs
have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we
describe the distribution, phenotype, and nerve injury-induced regulation of
NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs,
NECAB1/2 are expressed in around 70% of mainly small-and medium-sized neurons. Many …
Neuronal calcium (Ca2+)-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca2+-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca2+-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca2+-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord.
National Acad Sciences